wEPA
United States
Environmental Protection
Agency
DEVELOPMENT DOCUMENT FOR PROPOSED
EFFLUENT GUIDELINES AND STANDARDS FOR
THE CONSTRUCTION & DEVELOPMENT
CATEGORY
NOVEMBER 21, 2008
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U.S. Environmental Protection Agency
Office of Water (4303T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
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Disclaimer
Neither the United States government nor any of its employees, contractors, subcontractors, or
other employees makes any warranty, expressed or implied, or assumes any legal liability or
responsibility for any third party's use of, or the results of such use of, any information,
apparatus, product, or process discussed in this report, or represents that its use by such a third
party would not infringe on privately owned rights. References to proprietary technologies are
not intended to be an endorsement by the U.S. Environmental Protection Agency.
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Contents
1. OVERVIEW 1-1
1.1. INTRODUCTION 1-1
1.2. SUMMARY AND SCOPE OF PROPOSAL 1-2
2. BACKGROUND 2-1
2.1. LEGAL AUTHORITY 2-1
2.2. CLEAN WATER ACT 2-1
2.2.1. BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY
AVAILABLE 2-1
2.2.2. BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY 2-2
2.2.3. BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE.... 2-2
2.2.4. NEW SOURCE PERFORMANCE STANDARDS 2-3
2.2.5. PRETREATMENT STANDARDS FOR EXISTING SOURCES AND
PRETREATMENT STANDARDS FOR NEW SOURCES 2-3
2.2.6. EFFLUENT GUIDELINES SCHEDULE AND PREVIOUS ACTIONS
RELATED TO CONSTRUCTION AND DEVELOPMENT 2-3
2.2.7. NPDES PHASE I AND II STORMWATER RULES 2-5
2.3. POLLUTION PREVENTION ACT OF 1990 2-6
2.4. STATE REGULATIONS 2-7
3. DATA COLLECTION 3-1
3.1. INTRODUCTION 3-1
3.2. LITERATURE SEARCH 3-1
3.3. DATA AND INFORMATION PROVIDED IN RESPONSE TO THE 2002
REGULATORY ACTION 3-1
3.4. COMPILATION OF STATE CONTROL STRATEGIES, CRITERIA, AND
STANDARDS 3-1
3.5. OTHER DATA SOURCES 3-2
3.5.1. LAND USE DATA 3-2
3.5.2. NPDES PERMIT NOTICE OF INTENT DATA 3-12
3.5.3. CLIMATIC/RAINFALL DATA 3-12
3.5.4. SOILS DATA 3-22
3.5.5. VENDOR DATA FOR ACTIVE TREATMENT SYSTEMS 3-23
3.5.6. RAINFALL AND RUNOFF EROSIVITY FACTOR 3-23
3.5.7. HYDROLOGIC SOIL GROUPS 3-24
3.6. REFERENCES 3-31
4. INDUSTRY PROFILE 4-1
4.1. INTRODUCTION 4-1
4.2. INDUSTRY PRACTICES AND TRENDS 4-6
4.2.1. OVERVIEW OF CONSTRUCTION LAND-DISTURBING ACTIVITIES 4-6
4.2.2. CONSTRUCTION SITE SIZE CATEGORIES AND ESTIMATES OF
AMOUNT OF DISTURBED LAND 4-9
4.3. REFERENCES 4-26
5. SELECTION OF POLLUTANTS FOR REGULATION 5-1
5.1. INTRODUCTION 5-1
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5.2. POLLUTANTS ASSOCIATED WITH CONSTRUCTION AND LAND
DEVELOPMENT STORMWATER RUNOFF 5-1
5.2.1. SEDIMENT 5-1
5.2.2. METALS 5-3
5.2.3. PAHs, AND OIL AND GREASE 5-3
5.2.4. PATHOGENS 5-4
5.3. SELECTION OF POLLUTANTS FOR REGULATION 5-4
5.4. REFERENCES 5-5
6. LIMITATIONS AND STANDARDS: DATA SELECTION AND CALCULATION 6-1
6.1. INTRODUCTION 6-1
6.2. TURBIDITY 6-1
6.3. OVERVIEW OF DATA REVIEW AND CRITERIA 6-2
6.4. DATA SELECTED AS BASIS FOR PROPOSED LIMITATIONS 6-4
6.4.1. DATA SOURCES 6-4
6.4.2. SUMMARY OF DATA SUBMITTED FOR REVIEW 6-11
6.4.3. DATA REVIEW AND EXCLUSIONS 6-13
6.5. DATA AVERAGING PRIOR TO LIMITATION CALCULATIONS 6-15
6.5.1. DAILY VALUES FOR EACH TREATMENT SYSTEM 6-16
6.5.2. MULTIPLE TREATMENT SYSTEMS 6-17
6.5.3. FIELD DUPLICATES 6-17
6.6. LIMITATIONS 6-18
6.6.1. STATISTICALPERCENTILE BASIS FOR LIMITATIONS 6-18
6.6.2. LONG-TERM AVERAGE 6-18
6.6.3. VARIABILITY FACTOR 6-20
6.6.4. CALCULATION OF THE PROPOSED LIMITATION 6-22
6.6.5. ENGINEERING REVIEW 6-22
6.6.6. IMPORTANCE OF COMMENTS 6-25
6.6.7. MONITORING CONSIDERATIONS 6-26
6.6.8. COMPLIANCE 6-27
6.7. SUMMARY OF STEPS USED TO DERIVE THE PROPOSED
LIMITATIONS 6-29
6.8. REFERENCES 6-30
7. TECHNOLOGY ASSESSMENT 7-1
7.1. REVIEW OF HISTORICAL APPROACHES TO EROSION AND
SEDIMENT CONTROL 7-1
7.2. CONTROL TECHNIQUES 7-3
7.2.1. EROSION CONTROL AND PREVENTION 7-3
7.2.2. WATER HANDLING PRACTICES 7-27
7.2.3. SEDIMENT TRAPPING DEVICES 7-45
7.2.4. OTHER CONTROL PRACTICES 7-67
7.2.5. ADVANCED TREATMENT AND CONTROL TECHNOLOGIES 7-86
7.3. REFERENCES 7-97
8. REGULATORY DEVELOPMENT AND RATIONALE 8-1
8.1. DEVELOPMENT OF REGULATORY OPTIONS 8-1
8.2. OPTIONS CONTAINED IN THE PROPOSAL 8-1
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8.2.1. OPTION 1 - COMBINATION OF BEST MANAGEMENT PRACTICE
(BMP) STANDARDS AND SEDIMENT BASIN SIZING 8-1
8.2.2. OPTION 2 - COMBINATION OF BMP STANDARDS FOR ALL SITES
AND TURBIDITY STANDARD FOR SELECTED SITES 8-1
8.2.3. OPTION 3 - COMBINATION OF BMP STANDARDS FOR ALL SITES
AND TURBIDITY STANDARD FOR ALL SITES 10+ ACRES 8-2
8.3. OTHER OPTIONS EVALUATED 8-2
8.3.1. SITE SIZE 8-2
8.3.2. ANNUAL PRECIPITATION 8-2
8.3.3. SOIL PARAMETERS 8-2
8.4. BCT COST-REASONABLENESS ASSESSMENT 8-3
8.4.1. BACGKROUND ON THE BCT COST TEST 8-4
8.4.2. CALCULATION OF THE BCT COST TEST 8-4
8.5. REFERENCES 8-6
9. ESTIMATING INCREMENTAL COSTS FOR THE PROPOSED REGULATION 9-1
9.1. OVERVIEW 9-1
9.2. ANALYSIS OF STATE EQUIVALENCY 9-2
9.3. DEVELOPMENT OF MODEL CONSTRUCTION SITES AND SELECTION
OF INDICATOR CITIES 9-3
9.3.1. MODEL CONSTRUCTION SITES 9-3
9.3.2. ESTIMATION OF RAINFALL DEPTHS AND RUNOFF VOLUMES 9-4
9.3.3. ESTIMATION OF SEDIMENT BASIN VOLUMES AND ATS
TREATMENT VOLUMES 9-5
9.4. ESTIMATION OF COSTS 9-13
9.4.1. COMPONENTS OF COST 9-13
9.4.2. BASELINE AND INCREMENTAL COSTS 9-16
9.4.3. SOURCES AND STANDARDIZATION OF COST DATA 9-17
9.4.4. C&D COST SPREADSHEET MODEL 9-17
9.4.5. ESTIMATION OF COSTS FOR SEDIMENT TRAPS AND BASINS 9-18
9.4.6. ACTIVE TREATMENT SYSTEMS 9-19
9.4.7. SUMMARY OF OPTION COSTS 9-29
9.5. REFERENCES 9-54
10. ESTIMATING POLLUTANT LOAD REDUCTIONS 10-1
10.1. OVERVIEW OF APPROACH 10-1
10.2. ANALYSIS OF SOIL CHARACTERISTICS BY REGION 10-1
10.3. ESTIMATION OF SOIL EROSION RATES 10-4
10.4. ESTIMATION OF SEDIMENT REMOVAL EFFICIENCIES 10-11
10.5. CALCULATION OF NATIONAL LOADINGS AND REMOVALS BY
REGULATORY OPTION 10-22
10.6. REFERENCES 10-34
11. NON-WATER QUALITY ENVIRONMENTAL IMP ACTS 11-1
11.1. ENERGY REQUIREMENTS 11-1
11.1.1. ENERGY REQUIREMENTS ATTRIBUTABLE TO THE REGULATORY
OPTIONS 11-1
11.1.2. TREATMENT CHEMICAL PRODUCTION 11-2
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11.1.3. COMPARISON OF OPTION ENERGY REQUIREMENTS TO
CONSTRUCTION INDUSTRY 11-3
11.2. AIR EMISSIONS IMP ACTS 11-4
11.3. SOLID WASTE GENERATION 11-5
11.4. REFERENCES 11-5
APPENDIX A: Summary of State Construction and Development Requirements A-l
APPENDIX B: Literature Search Annotated Bibliography B-l
APPENDIX C: Analysis of Construction Industry Trends Using Notice of Intent Records C-l
APPENDIX D: Precipitation Data Representative of Maj or U. S. Metropolitan Areas D-1
APPEND IX E: Determination of Development Rates in U.S. Watersheds E-l
APPENDIX F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S.
Metropolitan Areas F-l
APPENDIX G: Turbidity Report Tables G-l
APPENDIX H: Lognormal Distribution Used for Site-Specific, Long-Term Averages and
Variability Factors H-l
APPENDIX I: Alternative Statistical Methods 1-1
Figures
Figure 3-1. NLCD 1992/2001 Land Cover Change Product near Seattle, Washington 3-3
Figure 3-2. EPA Region 1: Percent urban change 1992-2001 by ERF1_2 Watershed 3-6
Figure 3-3. EPA Region 2: Percent urban change 1992-2001 by ERF1_2 Watershed 3-6
Figure 3-4. EPA Region 3: Percent urban change 1992-2001 by ERF1_2 Watershed 3-7
Figure 3-5. EPA Region 4: Percent urban change 1992-2001 by ERF1_2 Watershed 3-7
Figure 3-6. EPA Region 5: Percent urban change 1992-2001 by ERF1_2 Watershed 3-8
Figure 3-7. EPA Region 6: Percent urban change 1992-2001 by ERF1_2 Watershed 3-8
Figure 3-8. EPA Region 7: Percent urban change 1992-2001 by ERF1_2 Watershed 3-9
Figure 3-9. EPA Region 8: Percent urban change 1992-2001 by ERF1_2 Watershed 3-9
Figure 3-10. EPA Region 9: Percent urban change 1992-2001 by ERF1_2 Watershed 3-10
Figure 3-11. EPA Region 10: Percent urban change 1992-2001 by ERF 1_2 Watershed 3-10
Figure 3-12. Average Annual Precipitation in the CONUS from PRISM 3-17
Figure 3-13. Surface Soil Layer Percent Clay Content 3-23
Figure 3-14. Annual R-Factor Values for CONUS 3-25
Figure 4-1. Areas of the CONUS Required to Meet Turbidity Limit 4-18
Figure 4-2. Alaska's Mean Annual Precipitation 1961 to 1990 4-19
Figure 4-3. Hawaii's Mean Annual Precipitation 1971 to 2000 4-20
Figure 7-1. General ATS Batch Operating Mode 7-88
Figure 7-2. Flow-through ATS Operating Mode 7-88
Figure 9-1. CSQA Settling Velocity Criteria for Sizing Sediment Basins 9-11
Figure 10-1. CSQA Settling Velocity Criteria for Sizing Sediment Basins 10-14
Figure 10-2. Indicator City Soil Particle Size Distributions 10-18
IV
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Figure 10-3. Illustration of Sediment Removal Efficiency for Baseline and Regulatory
Options 10-19
Tables
Table 3-1. State and National Estimates of Urban Land fromNLCD 3-4
Table 3-2. EPA Region Indicator Cities 3-13
Table 3-3. Rainfall Summary Data for Indicator Cities 3-15
Table 3-4. Percent of Developed Acres In-Scope for Various Annual Precipitation
Amounts 3-18
Table 3-5. Developed Acres In-Scope for Various Annual Precipitation Amounts 3-20
Table 3-6. Percent Developed Acres In-Scope for Various Annual R-Factor Values 3-26
Table 3-7. Developed Acres In-Scope for Various Annual R-F actor Values 3-28
Table 3-8. Hydrologic Soil Groups by State 3-30
Table 4-1. 2007 NAICS Subsectors, Industry Groups, and Industries Performing
Construction Activities that Might Disturb Land 4-3
Table 4-2. 1987 SIC Industry Groups Performing Construction Activities that Might
Disturb Land 4-5
Table 4-3. Summary of NOI Data 4-10
Table 4-4. NOI Derived Construction Site Size Distribution 4-11
Table 4-5. Estimated Number of Model Construction Projects Developed Annually 4-13
Table 4-6. Estimated Annually Developed Acreage Represented by Model Construction
Projects 4-15
Table 4-7. Annual State Developed Acres in Various Percent Clay Fractions 4-21
Table 4-8. State Total Acres in Various Percent Clay Fractions 4-23
Table 4-9. Acres Subject to Proposed Regulation 4-25
Table 5-1. Studies of Uncontrolled Soil Erosion as TSS from Construction Sites 5-3
Table 6-1. Data Sources and Site Identification 6-4
Table 6-2. Summary of Reported Turbidity Measurements (NTU) in Effluent 6-12
Table 6-3. Summary of Reported Turbidity Measurements (NTU) in Influent 6-13
Table 6-4. Summary of Reported Turbidity Measurements (NTU) in Effluent (After All
Reviews) 6-15
Table 6-5. Summary of Daily Values of Turbidity (NTU) in Effluent 6-16
Table 6-6. System-Specific Long-Term Averages Used in Limitation Calculations 6-19
Table 6-7. Summary Statistics Used to Evaluate Long-Term Average 6-20
Table 6-8. System-Specific Variability Factors Used in Limitation Calculations 6-21
Table 6-9. TSS Variability Factors in Recent Regulations 6-22
Table 6-10. Daily Values Greater Than Daily Maximum Limitation 6-25
Table 7-1. Scheduling Considerations for Construction Activities 7-5
Table 7-2. Conditions Where Vegetative Streambank Stabilization Is Acceptable 7-8
Table 7-3. Maximum Permissible Velocities for Individual Site Conditions for Grass
Swales 7-10
Table 7-4. Typical Mulching Materials and Application Rates 7-18
Table 7-5. Measured Reductions in Soil Loss for Different Mulch Treatments 7-18
Table 7-6. Cubic Yards of Topsoil Required for Application to Various Depths 7-26
Table 7-7. Grassed Swale Pollutant Removal Efficiency Data 7-33
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Table 7-8. Average Annual Operation and Maintenance Costs for a Grass Swale 7-34
Table 7-9. Recommended Pipe/Tubing Sizes for Slope Drains 7-37
Table 7-10. Slope Drain Characteristics 7-39
Table 7-11. Maximum Slope Lengths for SiltFences 7-47
Table 7-12. Typical Requirements for SiltFence Fabric 7-49
Table 7-13. Slope Lengths for Super SiltFences 7-53
Table 7-14. Minimum Requirements for Super SiltFence Geotextile Class F Fabric 7-53
Table 7-15. Maximum Land Slope and Distances above a Straw Bale Dike 7-55
Table 7-16. Weir Length for Sediment Traps 7-58
Table 7-17. Range of Measured Pollutant Removal for Sediment Detention Basins 7-59
Table 7-18. Common Concerns Associated with Sediment Traps 7-60
Table 7-19. Common Concerns Associated with Sediment Basins 7-66
Table 7-20. Riprap Sizes and Thicknesses 7-70
Table 7-21. Application Rates for Spray-On Adhesives 7-81
Table 7-22. Turbidity Reduction Values from PAM 7-85
Table 7-23. ATS Operating Modes 7-87
Table 7-24. ATS State Requirements/Recommendations 7-90
Table 7-25. Summary of Preliminary Vendor Costs 7-91
Table 7-26. Summary of Advanced Treatment System Case Studies 7-92
Table 7-27. Examples of Some Commonly Available Coagulants 7-93
Table 7-28. Chitosan Acetate Study Results 7-94
Table 7-29. DADMAC Acetate Study Results 7-95
Table 7-30. PAM Study Results 7-95
Table 7-31. Aluminum-based Coagulant Study Results 7-96
Table 8-1. Percent of Developed Acres Required to Meet Turbidity Limits for Various Clay
Contents 8-3
Table 8-2. POTW Cost Test Results 8-5
Table 8-3. Cost and Pollutant Removals for the Proposed BPT 8-6
Table 8-4. Industry Cost-Effectiveness Test Results 8-6
Table 9-1. Estimated Total Annual Costs of Regulatory Options for the C&D Industry 9-2
Table 9-2. Model Project Cost Assumptions 9-4
Table 9-3. State Runoff Coefficients for 2-Year, 24-Hour Storm Events 9-6
Table 9-4. State Runoff Coefficients for 10-Year, 6-Hour Storm Events 9-8
Table 9-5. Sediment Basin Sizes for States 9-12
Table 9-6. Model Project Treatment Volumes (million gallons) 9-14
Table 9-7. C&D Cost Spreadsheet Model Worksheets 9-17
Table 9-8. Sediment Basin Construction Cost Data 9-19
Table 9-9. ATS Costs for Large Residential Model Projects 9-20
Table 9-10. ATS Costs for Medium Residential Model Projects 9-21
Table 9-11. ATS Costs for Large Nonresidential Projects 9-22
Table 9-12. ATS Costs for Medium Nonresidential Projects 9-24
Table 9-13. ATS Costs for Large Transportation Projects 9-25
Table 9-14. ATS Costs for Medium Transportation Projects 9-26
Table 9-15. Developed Acres with R-Factor > 50 and Clay Content > 10% 9-28
Table 9-16. Acres and Model Projects In-Scope for Turbidity Limit of Option 2 9-30
Table 9-17. Acres Required to Install Larger Sediment Basins Under Option 2 9-32
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Table 9-18. Model Projects Required to Install Larger Sediment Basins Under Option 2 9-34
Table 9-19a. Option 1 Costs by Model Project Type and State ($2008); Transportation 9-36
Table 9-19b. Option 1 Costs by Model Project Type and State ($2008); Residential 9-38
Table 9-19c. Option 1 Costs by Model Project Type and State ($2008); Nonresidential 9-40
Table 9-20. Option 2 Costs for Sites Required to Meet Turbidity Standard ($2008) 9-42
Table 9-2la. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008);
Transportation 9-44
Table 9-21b. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008);
Residential 9-46
Table 9-2Ic. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008);
Nonresidential 9-48
Table 9-22. Option 2 Total Costs ($2008) 9-50
Table 9-23. OptionS Total Costs ($2008) 9-52
Table 10-1. Summary of STATSGO Evaluation of Indicator City Locations 10-2
Table 10-2. Indicator City Surface Soil Characterization 10-2
Table 10-3. Summary of STATSGO Soil Data Extraction for Indicator Cities 10-3
Table 10-4. Slope Ranges from STATSGO and Computed Regional Slope Ranges for
Estimating Soil Erosion Yield 10-4
Table 10-5. Data Sources and Data Processing to Obtain RUSLE Factors 10-5
Table 10-6a. Estimated Soil Eroded from Large Transportation, Medium Transportation
and Small Transportation Model Construction Proj ects (Tons Per Acre) 10-6
Table 10-6b. Estimated Soil Eroded from Large and Medium Residential Model
Construction Projects (Tons Per Acre) 10-6
Table 10-6c. Estimated Soil Eroded from Large and Medium Nonresidential Model
Construct on Proj ects (Tons Per Acre) 10-7
Table 10-6d. Estimated Soil Eroded from Small Nonresidential and Small Residential
Model Construction Proj ects (Tons Per Acre) 10-7
Table 10-7. Estimated Range of Average Annual Construction Site Yield for Model
Construction Proj ects 10-8
Table 10-8. Allocation of States/Commonwealths/Territories to Representative Indicator
City 10-9
Table 10-9. Estimated Annual Construction Site Soil Erosion by State without Any
Controls (Tons of Sediment) 10-10
Table 10-10. Critical Particle Sizes Removed Under Baseline Conditions 10-14
Table 10-11. Critical Particle Sizes Removed Under Option 1 10-15
Table 10-12. Percent of Eroded Construction Site Sediment Released from Sediment
Basins 10-21
Table 10-13. Estimated Annual State Baseline Construction Site Discharged Loads 10-23
Table 10-13a. Estimated Annual Option 1 Construction Site Discharged Loads 10-25
Table 10-13b. Estimated Annual Option 2 Construction Site Discharged Loads 10-26
Table 10-13c. Estimated Annual Option 3 Construction Site Discharged Loads 10-27
Table 10-14a. Estimated Annual Option 1 Construction Site Eroded Sediment Captured 10-29
Table 10-14b. Estimated Annual Option 2 Construction Site Eroded Sediment Captured 10-30
Table 10-14c. Estimated Annual Option 3 Construction Site Eroded Sediment Captured 10-31
Table 10-15. Reductions in Estimated National Construction Site Discharged Material from
Baseline Discharge Levels (Million Tons of TSS per Year) for Regulatory Options. 10-33
Vll
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Table 11-1. Estimated Energy Consumption by Regulatory Option 11-1
Table 11-2. Maximum Chitosan Acetate Required under EPA Options 11-2
Table 11-3. US Acrylamide / PAM Demand* 11-3
Table 11-4. 2002 Energy Use in NAICS Category 23 11-3
Table 11-5. Estimated Incremental Energy Usage by Regulatory Option 11-4
Table 11-6. Estimated Incremental Air Emissions by Regulatory Option (Pounds/Year) 11-5
Vlll
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Section 1: Overview
1. OVERVIEW
1.1. INTRODUCTION
This document presents technical information to support the U.S. Environmental Protection
Agency's (EPA's) decision and compliments the Agency' s Economic Analysis for Proposed
Effluent Guidelines and Standards for the Construction and Development Category (EPA-821-
R-08-008), and the Environmental Impact and Benefits Assessment for Proposed Effluent
Guidelines and Standards for the Construction and Development Category (EPA-821-R-08-
009).
A summary of the information contained in the sections of this document is as follows:
Section 2 presents a summary of the legal authority for effluent guidelines and the
existing EPA storm water program.
Section 3 summarizes the data collection activities and the analytical tools and
processes followed to support the final action.
Section 4 summarizes the characteristics of the construction and development
industry, including major indicators of industry size and annual construction activity.
Section 5 presents a description of pollutants in stormwater runoff known to be the
most prevalent and of greatest concern to the environment. It also presents the
selection of pollutants for the proposed regulation.
Section 6 presents the method and data used to establish limitations and standards.
Section 7 presents information and data on erosion and sediment control (ESC)
strategies used by the construction and development industry, including applicability,
costs, and efficiencies of various technologies.
Section 8 presents a description of the regulatory options EPA considered for
developing the proposal.
Section 9 presents a description of the approach EPA used for developing model
construction sites and selecting indicator cities used in analyzing stormwater BMP
costs and pollutant loading reductions under baseline conditions as well as under the
regulatory options proposed.
Section 10 summarizes the approach EPA used to estimate the pollutant loads and
load reductions for the regulatory options EPA considered.
Section 11 summarizes the non-water quality environmental impacts, including the
energy requirements, air emissions impacts, and solid waste generation of each
proposed regulatory option.
Page 1-1
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Section 1: Overview
1.2. SUMMARY AND SCOPE OF PROPOSAL
EPA is proposing to establish effluent limitations guidelines (ELGs) and new source
performance standards (NSPS) for stormwater discharges from the construction and development
industry. These guidelines and standards would require discharges from certain construction sites
to meet a numeric turbidity limit. The guidelines and standards would also require all
construction sites currently required to obtain a National Pollutant Discharge Elimination System
(NPDES) permit to implement a variety of best management practices (BMPs) designed to limit
erosion and control sediment discharges from construction sites. EPA evaluated three options in
developing the proposed rule. These options are described below:
Option 1 would establish minimum sizing criteria for sediment basins used at
construction sites with 10 or more disturbed acres draining to one location. Under this
option, permittees would be required to install sediment basins that provide either
3,600 cubic feet per acre of runoff storage, or be designed to store runoff from the
local 2-year, 24-hour storm event. This option also includes requirement for
implementing a variety of ESCs on all construction sites that are required to obtain a
permit.
Option 2 contains the same requirements as Option 1. In addition, construction sites
of 30 or more acres would be required to meet a numeric turbidity limit in stormwater
discharges from the site. The numeric turbidity standard would be applicable to
stormwater discharges for all storm events up to the local 2-year, 24-hour event. The
turbidity standard would apply only to construction sites in areas where the rainfall
runoff erosivity factor (R-factor) as defined in the Revised Universal Soil Loss
Equation (RUSLE) is greater than or equal to 50 and if the soils on the site contain 10
percent or more by mass of soil particles smaller than 2 microns in diameter.
Option 3 contains the same requirements as Option 1. Option 3 also requires all sites
with 10 or more acres of disturbed land to meet a numeric turbidity standard. The
turbidity standard would apply to all sites, regardless of soil types or R-factor. The
turbidity standard would apply to all stormwater discharges for all storm events up to
the local 2-year, 24-hour event.
EPA estimates that Option 1 would cost approximately $132 million dollars per year, reduce
sediment discharges from construction sites by approximately 670 million pounds per year, and
result in benefits of $11 million per year. EPA estimates that Option 2 would cost approximately
$1.9 billion dollars per year, reduce sediment discharges from construction sites by
approximately 26 billion pounds per year, and result in benefits of $196 million per year. EPA
estimates that Option 3 would cost approximately $3.8 billion dollars per year, reduce sediment
discharges from construction sites by approximately 50 billion pounds per year, and result in
benefits of $322 million per year.
Page 1-2
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Section 2: Background
2. BACKGROUND
2.1. LEGAL AUTHORITY
The U.S. Environmental Protection Agency (EPA) is proposing Effluent Limitation Guidelines
for discharges associated with construction and development activities under the authority of
Parts 301, 304, 306, 308, 402, and 501 of the Clean Water Act (CWA) (the Federal Water
Pollution Control Act), 33 United States Code (U.S.C.) 1311, 1314, 1316, 1318, 1342, and 1361.
This section describes EPA's legal authority for issuing the regulation, existing state regulations,
and other federal regulations associated with construction and development activities.
2.2. CLEAN WATER ACT
Congress adopted the CWA to "restore and maintain the chemical, physical, and biological
integrity of the nation's waters" (section 101(a), 33 U.S.C. 1251(a)). To achieve this goal, the
CWA prohibits the discharge of pollutants into navigable waters except in compliance with the
statute. CWA Part 402 requires point source discharges to obtain a permit under the National
Pollutant Discharge Elimination System (NPDES). These permits are issued by EPA regional
offices or authorized state agencies.
Following enactment of the Federal Water Pollution Control Amendments of 1972 (Pub.L. 92-
500, October 18, 1972), EPA and the states issued NPDES permits to thousands of dischargers,
both industrial (e.g. manufacturing, energy and mining facilities) and municipal (sewage
treatment plants). As required under Title III of the Act, EPA promulgated effluent limitation
guidelines and standards for many industrial categories, and these requirements are incorporated
into the permits.
The Water Quality Act of 1987 (Pub.L. 100-4, February 4, 1987) amended the CWA. The
NPDES program was expanded by defining municipal and industrial stormwater discharges as
point sources. Industrial stormwater dischargers, municipal separate storm sewer systems (MS4s)
and other stormwater dischargers designated by EPA must obtain NPDES permits pursuant to
section 402(p) (33 U.S.C. 1342(p)).
2.2.1. BEST PRACTICABLE CONTROL TECHNOLOGY CURRENTLY AVAILABLE
In guidelines for a point source category, EPA may define Best Practicable Control Technology
(BPT) effluent limits for conventional, toxic, and nonconventional pollutants. In specifying BPT,
EPA looks at a number of factors. EPA first considers the cost of achieving effluent reductions in
relation to the effluent reduction benefits. The Agency also considers the age of the equipment
and facilities, the processes employed and any required process changes, engineering aspects of
the control technologies, non-water quality environmental impacts (including energy
requirements), and such other factors as the Agency deems appropriate (CWA section
304(b)(l)(B)). Traditionally, EPA establishes BPT effluent limitations on the basis of the
average of the best performance of facilities within the category of various ages, sizes, processes
or other common characteristics. Where existing performance is uniformly inadequate, EPA may
require higher levels of control than currently in place in a category if the Agency determines
Page 2-1
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Section 2: Background
that the technology can be practically applied. See A Legislative History of the Federal Water
Pollution Control Act Amendments of 1972, U.S. Senate Committee of Public Works, Serial No.
93-1, January 1973, p. 1468.
In addition, the Act requires a cost-reasonableness assessment for BPT limitations. In
determining the BPT limits, EPA considers the total cost of treatment technologies in relation to
the effluent reduction benefits achieved. This inquiry does not limit EPA's broad discretion to
adopt BPT limitations that are achievable with available technology unless the required
additional reductions are "wholly out of proportion to the costs of achieving such marginal level
of reduction." See Legislative History, op. cit, p. 170. Moreover, the inquiry does not require the
Agency to quantify benefits in monetary terms. See, for example, American Iron and Steel
Institute v. EPA, 526 F. 2d 1027 (3rd Cir., 1975).
In balancing costs against the benefits of effluent reduction, EPA considers the volume and
nature of expected discharges after application of BPT, the general environmental effects of
pollutants, and the cost and economic impacts of the required level of pollution control. In past
effluent limitation guidelines and standards, BPT cost-reasonableness removal figures have
ranged from $0.21 to $33.71 per pound removed in year 2000 dollars. In developing guidelines,
the Act does not require consideration of water quality problems attributable to particular point
sources, or water quality improvements in particular bodies of water. See Weyerhaeuser
Company v. Costle, 590 F. 2d 1011 (D.C. Cir. 1978).
2.2.2. BEST CONVENTIONAL POLLUTANT CONTROL TECHNOLOGY
The 1977 amendments to the CWA required EPA to identify effluent reduction levels for
conventional pollutants associated with Best Conventional Pollutant Control Technology (BCT)
for discharges from existing point sources. BCT is not an additional limitation but replaces Best
Available Technology Economically Achievable (BAT) for control of conventional pollutants. In
addition to other factors specified in section 304(b)(4)(B), the CWA requires that EPA establish
BCT limitations after consideration of a two-part cost-reasonableness test. EPA explained its
methodology for developing BCT limitations in July 1986 (51 Federal Register [FR] 24974).
Section 304(a)(4) designates the following as conventional pollutants: biochemical oxygen
demand (BOD5), total suspended solids (TSS), fecal coliform, pH, and any additional pollutants
defined by the Administrator as conventional. The Administrator designated oil and grease as an
additional conventional pollutant on July 30, 1979 (44 FR 44501). A primary pollutant of
concern at construction sites, sediment, is commonly measured as TSS.
2.2.3. BEST AVAILABLE TECHNOLOGY ECONOMICALLY ACHIEVABLE
In general, BAT effluent guidelines (CWA section 304(b)(2)) represent the best existing
economically achievable performance of direct discharging plants in the subcategory or category.
The factors considered in assessing BAT include the cost of achieving BAT effluent reductions,
the age of equipment and facilities involved, the processes employed, engineering aspects of the
control technology, potential process changes, non-water quality environmental impacts
(including energy requirements), and such factors as the Administrator deems appropriate. The
Agency retains considerable discretion in assigning the weight to be accorded to these factors.
Page 2-2
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Section 2: Background
An additional statutory factor considered in setting BAT is economic achievability. Generally,
EPA determines the economic achievability on the basis of the total cost to the subcategory and
the overall effect of the rule on the industry's financial health. The Agency may base BAT
limitations on effluent reductions attainable through changes in a facility's processes and
operations. As with BPT, where existing performance is uniformly inadequate, EPA may base
BAT on technology transferred from a different subcategory or from another category. In
addition, the Agency may base BAT on manufacturing process changes or internal controls, even
when such technologies are not common industry practice.
2.2.4. NEW SOURCE PERFORMANCE STANDARDS
New Source Performance Standards (NSPS) reflect effluent reductions that are achievable on the
basis of the best available demonstrated control technology. New facilities have the opportunity
to install the best and most efficient production processes and wastewater treatment technologies.
As a result, NSPS should represent the greatest degree of effluent reduction attainable through
the application of the best available demonstrated control technology for all pollutants (i.e.,
conventional, nonconventional, and priority pollutants). In establishing NSPS, CWA Part 306
directs EPA to take into consideration the cost of achieving the effluent reduction and any non-
water quality environmental impacts and energy requirements.
2.2.5. PRETREATMENT STANDARDS FOR EXISTING SOURCES AND
PRETREATMENT STANDARDS FOR NEW SOURCES
The CWA also defines standards for indirect discharges, i.e., discharges into publicly owned
treatment works (POTWs). Such standards are Pretreatment Standards for Existing Sources
(PSES) and Pretreatment Standards for New Sources (PSNS) under section 307(b).
2.2.6. EFFLUENT GUIDELINES SCHEDULE AND PREVIOUS ACTIONS RELATED
TO CONSTRUCTION AND DEVELOPMENT
CWA section 304(m) requires EPA to publish a plan every 2 years that consists of three
elements. First, under section 304(m)(l)(A), EPA is required to establish a schedule for the
annual review and revision of existing effluent guidelines in accordance with section 304(b).
Section 304(b) applies to ELGs for direct dischargers and requires EPA to revise such
regulations as appropriate. Second, under section 304(m)(l)(B), EPA must identify categories of
sources discharging toxic or nonconventional pollutants for which EPA has not published BAT
ELGs under section 304(b)(2) or NSPS under Part 306. Finally, under section 304(m)(l)(C),
EPA must establish a schedule for the promulgation of BAT and NSPS for the categories
identified under subparagraph (B) not later than 3 years after being identified in the 304(m) plan.
Section 304(m) does not apply to pretreatment standards for indirect dischargers, which EPA
promulgates pursuant to CWA sections 307(b) and 307(c).
On October 30, 1989, Natural Resources Defense Council, Inc. (NRDC), and Public Citizen,
Inc., filed an action against EPA in which they alleged, among other things, that EPA had failed
to comply with section 304(m). Plaintiffs and EPA agreed to a settlement of that action in a
consent decree entered on January 31, 1992 (Natural Resources Defense Council et al v.
Whitman, D.D.C. Civil Action No. 89-2980). The consent decree, which has been modified
Page 2-3
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Section 2: Background
several times, established a schedule by which EPA is to propose and take final action for 11
point source categories identified by name in the decree and for eight other point source
categories identified only as new or revised rules, numbered 5 through 12. EPA selected the
Construction and Development (C&D) category as the subject for new or revised rule #10. The
decree, as modified, calls for the Administrator to sign a proposed ELG for the C&D category no
later than May 15, 2002, and to take final action on that proposal no later than March 31, 2004.
A settlement agreement between the parties, signed on June 28, 2000, requires that EPA develop
regulatory options applicable to discharges from construction, development, and redevelopment
covering site sizes included in the Phase I and Phase IINPDES stormwater rules (i.e., 1 acre or
greater). EPA is required to develop options including numeric effluent limitations for
sedimentation and turbidity; control of construction site pollutants other than sedimentation and
turbidity (e.g., discarded building materials, concrete truck washout, trash); best management
practices (BMPs) for controlling post-construction runoff; BMPs for construction sites; and
requirements to design stormwater controls to maintain pre-development runoff conditions where
practicable.
On June 24, 2002, EPA published a proposed rule for the C&D category that contained several
options for the control of stormwater discharges from construction sites, including effluent
limitations guidelines (ELGs) and NSPS. (67 FR 42644; June 24, 2002). In a final action on
April 26, 2004, EPA determined that national ELGs would not be the most effective way to
control discharges from construction sites, and instead chose to rely on the range of existing
programs, regulations, and initiatives that already existed at the federal, state, and local level.
(69 FR 22472).
The June 28, 2000, settlement agreement also required EPA to issue guidance to MS4s and other
permittees on maintenance of post-construction BMPs identified in the proposed ELGs. Because
EPA's proposal or final action did not contain requirements for post-construction BMPs, this
guidance was considered no longer necessary and therefore was not fully developed. However, a
draft of the maintenance guidance that was prepared while EPA was considering including
options for post-construction BMPs is contained in the public docket.
On October 6, 2004, NRDC and Waterkeeper Alliance, as well as the States of New York and
Connecticut filed a motion against EPA alleging that EPA failed to promulgate ELGs and NSPS
as required by the Clean Water Act. On December 1, 2006, the district courtin Natural
Resources Defense Council, et al. v. U.S. Environmental Protection Agency, et al, 437
F.Supp.2d 1137, 1139 (C.D. Cal.2006)held that CWA section 304(m), read together with
CWA section 304(b), imposes on EPA a mandatory duty to promulgate ELGs and NSPS for
industrial point source categories named in a CWA section 304(m) plan. EPA argued during this
litigation that the Agency is required only by statute to publish a biennial schedule listing
potential industries to regulate and that EPA is not compelled to actually promulgate regulations
for those industries identified in the plan. The court found that merely publishing a schedule is
not reasonable and that EPA has a mandatory duty to promulgate effluent guidelines for
categories of industry listed in the biennial effluent guidelines plan. The court also found that the
review and comment process serves to elicit response to the content of ELGs, not to the
advisability of promulgating them at all. The court ordered EPA to publish proposed regulations
in the FR by December 1, 2008, and to promulgate ELGs and NSPS for the C&D category as
soon as practicable, but no later than December 1, 2009.
Page 2-4
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Section 2: Background
2.2.7. NPDES PHASE I AND II STORMWATER RULES
As authorized by the CWA, the NPDES permit program was established to control water
pollution by regulating point sources that discharge pollutants into waters of the United States.
Stormwater runoff from construction activities can have a significant impact on water quality.
The NPDES Stormwater program requires operators of construction sites to apply for either a
general permit or an individual permit under the NPDES Phase I and II Stormwater rules. Phase I
of EPA's Stormwater program was promulgated in 1990 under the CWA and addresses, among
other discharges, discharges from construction activities disturbing 5 acres or more of land.
Phase II of the NPDES Stormwater program, promulgated in 1999, expands the Phase I Rule by
addressing Stormwater discharges from small construction sites disturbing between 1 and 5 acres.
In addition, operators of small construction sites are also required to develop and implement a
Stormwater pollution prevention plan (SWPPP), which includes implementation of the
appropriate ESC BMPs. The BMP selection and design are at the discretion of permittees (in
conformance with applicable state or local requirements). Moreover, construction activities
disturbing less than 1 acre are also included in Phase II of the NPDES Stormwater program if
they are part of a larger, common plan of development or sale with a planned disturbance of
equal to or greater than 1 acre and less than 5 acres, or if they are designated by the NPDES
permitting authority.
Most states are authorized to implement the Stormwater NPDES permitting program. However,
EPA remains the permitting authority in a few states, territories, and on most Indian country
lands. For construction (and other land disturbing activities) in areas where EPA is the permitting
authority, operators must meet the requirements of the EPA Construction General Permit (CGP).
The current CGP became effective on June 30, 2008 (as modified effective September 29, 2008)
and expires on June 30, 2010. This permit contains substantially the same terms and conditions
as the 2003 CGP. In response to comments on the proposal, EPA has reorganized the content of
the 2003 permit to better clarify existing requirements. The 2008 CGP applies only to new
discharges. Construction site operators with permit coverage under the 2003 CGP may continue
to operate under the terms of conditions of that permit and need not file a new Notice of Intent
for coverage under the 2008 CGP. Permit coverage is now available for eligible construction
activities in New Hampshire, Oklahoma, Texas, Puerto Rico, federal facilities, and Indian
country lands in Colorado and Montana.
The 2003 permit expanded coverage from the 1998 CGP that provided coverage for large
construction sites (i.e., those disturbing greater than 5 acres) to include both small and large
construction activities (i.e., any project disturbing greater than 1 acre). Small construction
activity was added to the 2003 CGP in response to the promulgation of the NPDES Phase II
Rule.
A major provision required by the CGP is preparation of a SWPPP. The SWPPP focuses on two
major requirements: (1) Providing a site description that identifies sources of pollution to
Stormwater discharges associated with industrial activity on site; and (2) identifying and
implementing appropriate measures to reduce pollutants in Stormwater discharges to ensure
compliance with the terms and conditions of the permit. All SWPPPs must be developed in
accordance with sound engineering practices and must be developed specific to the site. For
Page 2-5
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Section 2: Background
coverage under the permit, the SWPPP must be prepared before commencement of construction
and then updated as appropriate. Commencement of construction activities is defined as the
initial disturbance of soils associated with clearing, grading, or excavating activities or other
construction-related activities (e.g., stockpiling of fill material).
The permit also clarifies that once a definable area of the site has been finally stabilized, no
further SWPPP requirements apply to that portion of the site as long as the SWPPP has been
updated accordingly to identify that portion of the site as complete. The SWPPP must be
implemented as written from commencement of construction activity until final stabilization is
complete. Stabilization practices include seeding of temporary vegetation, seeding of permanent
vegetation, mulching, geotextiles, sod stabilization, vegetative buffer strips, preservation of trees
and mature vegetative buffer strips, and other appropriate measures. For a detailed description of
all permit requirements and conditions, see the CGP.
2.3. POLLUTION PREVENTION ACT OF 1990
The Pollution Prevention Act of 1990 (PPA) (42 U.S.C. 13101 et seq., Pub. L. 101-508,
November 5, 1990) makes pollution prevention the national policy of the United States. The PPA
identifies an environmental management hierarchy in which pollution "should be prevented or
reduced whenever feasible; pollution that cannot be prevented should be recycled in an
environmentally safe manner, whenever feasible; pollution that cannot be prevented or recycled
should be treated in an environmentally safe manner whenever feasible; and disposal or release
into the environment should be employed only as a last resort..." (42 U.S.C. 13103). In short,
preventing pollution before it is created is preferable to trying to manage, treat, or dispose of it
after it is created. According to the PPA, source reduction reduces the generation and release of
hazardous substances, pollutants, wastes, contaminants, or residuals at the source, usually within
a process. The term source reduction "...includes equipment or technology modifications,
process or procedure modifications, reformulation or redesign of products, substitution of raw
materials, and improvements in housekeeping, maintenance, training, or inventory control. The
term 'source reduction' does not include any practice which alters the physical, chemical, or
biological characteristics or the volume of a hazardous substance, pollutant, or contaminant
through a process or activity which itself is not integral to or necessary for the production of a
product or the providing of a service." In effect, source reduction means reducing the amount of
a pollutant that enters a waste stream or that is otherwise released into the environment before
out-of-process recycling, treatment, or disposal.
Although the PPA does not explicitly address stormwater discharges or discharges from
construction sites, the principles of the PPA are implicit in many of the practices used to reduce
pollutant discharges from construction sites. These include controls that minimize the potential
for erosion such as proper phasing of construction, retention of on-site vegetation and
stabilization of disturbed areas as soon as practicable. These controls and practices are described
in Section 7 of this document.
Page 2-6
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Section 2: Background
2.4. STATE REGULATIONS
States and municipalities have been regulating discharges of runoff from the construction and
land development industry to varying degrees for some time. A compilation of state CGPs and
regulations was prepared to help establish the baseline for national and regional levels of control.
Data were collected by reviewing state CGPs, Web sites, summary references, and state erosion
and sediment control and/or stormwater management guidance manuals. The state regulatory
data are discussed in Sections 3.4 and 9.2 of this document, and the complete data sheets are
included in Appendix A.
Page 2-7
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Section 3: Data Collection
3. DATA COLLECTION
3.1. INTRODUCTION
As part of the regulatory efforts to develop the proposed Construction and Development (C&D)
regulations in 2002 and the related final action in 2004, the U.S. Environmental Protection
Agency (EPA) gathered and evaluated an extensive amount of technical and economic data from
various sources. EPA used much of the data collected for the previous rulemaking effort in
support of this effort. EPA also collected additional data and information to support the technical
analyses used in developing this proposal. This section summarizes EPA's data collection
efforts.
3.2. LITERATURE SEARCH
A literature search was performed to obtain additional information on various erosion and
sediment control (ESC) technologies that pertain to the C&D industry. Journal articles and
professional conference proceedings were reviewed to collect recent data and information related
to ESC design and installation criteria, performance, and related costs. Appendix B provides
annotated bibliographies for the journal articles and professional conference proceedings that
EPA reviewed for possible use in developing this proposal.
3.3. DATA AND INFORMATION PROVIDED IN RESPONSE TO THE 2002
REGULATORY ACTION
In response to the previous rulemaking efforts for the C&D industry, EPA received numerous
public comments on most aspects of the 2002 proposed rule. EPA considered these comments in
developing this proposal.
3.4. COMPILATION OF STATE CONTROL STRATEGIES, CRITERIA, AND
STANDARDS
EPA compiled and evaluated existing state program information for the control of construction
site stormwater. The data were collected by reviewing state construction general permits (CGPs),
Web sites, summary references, state regulations, and ESC design and guidance manuals. A
summary of criteria and standards for construction site stormwater ESC that are implemented by
states is presented in Appendix A. More information on this analysis is in Section 9.2, Analysis
of State Equivalency. Appendix A also includes updated state information that EPA obtained in
early 2007, state-level data sheets and information originally presented in Section 7 and
Appendix D of the 2004 Development Document for Final Action for Effluent Guidelines and
Standards for the Construction and Development Category (EPA-821-B-04-001), and
information originally presented in Appendix A of the June 2002 Development Document for
Proposed Effluent Guidelines and Standards for the Construction and Development Category
(EPA-821-R-02-007).
Page 3-1
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Section 3: Data Collection
3.5. OTHER DATA SOURCES
3.5.1. LAND USE DATA
EPA accessed a number of sources of land cover information at a national scale for use in
estimating the potential number of acres subject to C&D activities.
3.5.1.1. National Land Cover Dataset
The National Land Cover Database (NLCD) provides a national source of data on land cover
change. The Multi-Resolution Land Characteristics Consortium (MRLC) has produced the
NLCD data sets that created a 30-meter resolution land cover data layer over the conterminous
United States (CONUS) from Landsat Thematic Mapper satellite imagery. NLCD data are
publicly available for the years 1992 and 2001 (see http://www.epa.gov/mrlc/ and
http://www.mrlc.gov/).
Because of new developments in mapping methodology, new sources of input data, and changes
in the mapping legend for the 2001 NLCD confound direct comparison between NLCD 2001 and
the 1992 NLCD (MRLC 1992 and 2001), the U.S. Geological Survey (USGS) prepared and
released the NLCD 1992/2001 Retrofit Land Cover Change Product. The NLCD 1992/2001
Retrofit Land Cover Change Product was developed to offer more accurate direct change
analysis between the two products.
The NLCD 1992/2001 Retrofit Land Cover Change Product uses a specially developed
methodology to provide land cover change information at the Anderson Level I classification
scale, relying on decision tree classification of Landsat imagery from 1992 and 2001. While
NLCD 1992 reported on developed land in the categories of low residential intensity, high
residential intensity, commercial/industrial/transportation, and urban/recreational grasses, NLCD
2001 reported categories of developed low, medium, high, and open space. To compare change
between the two data sets, the developed categories were merged into one overall urban class.
Unchanged pixels between the two dates are coded with the NLCD 2001 Anderson Level I class
code, while changed pixels are labeled with afrom-to land cover change value. Modified
Anderson Level 1 Classifications include the following:
Open water
Urban
Barren
Forest
Grassland/Shrub
Agriculture
Wetlands Ice/Snow
The NLCD 1992/2001 Retrofit Land Cover Change Product was intended to provide a current,
consistent, and seamless data set for the United States at medium spatial resolution for Anderson
Level 1 classes. This land cover change map and all documents pertaining to it are considered
provisional until a formal accuracy assessment can be conducted.
Page 3-2
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Section 3: Data Collection
EPA used the NLCD to estimate the annual number of acres of land converted to urban land uses
in the United States during the period between 1992 and 2001. This estimate serves as a
surrogate measure of the acres of construction activities subject to national effluent guidelines
regulations, because no national database of the number and size of construction activities exists.
Figure 3-1 illustrates an example of the Reach File Version 1.0 (RFl)-level analysis of the
NLCD data.
Legend
&
| | RF1 watershed
1992-2001 Change Data
| Change to Urban
NLCD Class
Modified Anderson
| | Agriculture
| | Barren
~^\ Forest
I | Grassland/Shrub
| | Ice/Snow
] Urban
~l Wetlands
Figure 3-1. NLCD 1992/2001 Land Cover Change Product near Seattle, Washington.
Table 3-1 summarizes the national- and state-level estimates obtained from the NLCD analysis.
Figures 3-2 through 3-11 graphically present the results of the NLCD land use change analysis at
the RF1 level. Results are presented as percent urban change between 1992 and 2001. (See DCN
43097 in the Administrative Record for an index of the NLCD-related analyses conducted for the
proposed rule.)
Page 3-3
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Section 3: Data Collection
Table 3-1. State and National Estimates of Urban Land from NLCD
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
1992
Urban
acres
2,066,843
2001
Urban
acres
2,197,370
% State
that is
developed
(1992)
6.4%
% State
that is
developed
(2001)
6.8%
Annual rate of
development, 1992-
2001
(acres)
14,503
NO DATA
1,285,258
1,836,496
6,278,143
1,609,387
727,078
113,052
4,526,626
3,026,921
1,407,907
1,912,867
6,524,934
1,751,860
736,131
120,552
4,869,204
3,320,243
1.8%
5.5%
6.2%
2.4%
23.4%
9.4%
13.0%
8.2%
2.0%
5.8%
6.5%
2.6%
23.6%
10.0%
14.0%
9.0%
13,628
8,486
27,421
15,830
1,006
833
38,064
32,591
NO DATA
847,520
4,014,480
2,238,170
2,527,225
2,463,194
1,740,669
1,788,423
653,697
698,386
1,174,234
3,746,569
2,648,001
1,721,138
2,845,661
1,187,901
1,699,570
572,706
426,786
1,124,705
799,207
2,682,301
2,816,229
1,667,029
3,549,025
2,387,508
1,552,824
3,006,384
173,764
1,487,194
1,315,111
2,189,700
8,229,892
898,587
4,198,994
2,349,522
2,618,075
2,666,039
1,830,453
1,904,013
694,157
757,203
1,204,116
3,949,025
2,731,981
1,827,846
2,967,610
1,246,005
1,754,268
646,109
442,861
1,163,128
841,237
2,751,793
2,984,873
1,725,866
3,705,609
2,538,082
1,618,391
3,150,410
177,161
1,632,717
1,389,905
2,307,498
8,781,625
1.6%
11.3%
9.9%
7.1%
4.7%
6.8%
6.6%
3.3%
11.3%
23.9%
10.3%
5.2%
5.7%
6.5%
1.3%
3.5%
0.8%
7.5%
23.7%
1.0%
8.9%
9.1%
3.9%
13.6%
5.4%
2.5%
10.4%
27.0%
7.7%
2.7%
8.3%
5.0%
1.7%
11.8%
10.4%
7.4%
5.1%
7.2%
7.0%
3.5%
12.2%
24.5%
10.9%
5.4%
6.1%
6.8%
1.4%
3.6%
0.9%
7.7%
24.5%
1.1%
9.1%
9.6%
4.0%
14.2%
5.7%
2.6%
10.9%
27.5%
8.5%
2.9%
8.8%
5.3%
5,674
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
6,456
6,078
8,156
1,786
4,269
4,670
7,721
18,738
6,537
17,398
16,730
7,285
16,003
377
16,169
8,310
13,089
61,304
Page 3-4
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Section 3: Data Collection
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of
Columbia
Nation
1992
Urban
acres
758,031
304,570
1,818,500
2,286,574
1,016,805
2,345,956
491,168
26,381
96,492,992
2001
Urban
acres
833,531
309,695
1,954,814
2,401,699
1,048,419
2,414,075
516,758
26,973
101,802,191
% State
that is
developed
(1992)
1.4%
5.4%
7.2%
5.4%
6.7%
6.7%
0.8%
82.8%
% State
that is
developed
(2001)
1.6%
5.5%
7.7%
5.7%
6.9%
6.9%
0.8%
83.8%
Annual rate of
development, 1992-
2001
(acres)
8,389
569
15,146
12,792
3,513
7,569
2,843
66
589,911
Page 3-5
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Section 3: Data Collection
Developed from 1992-2001
Figure 3-2. EPA Region 1: Percent urban change 1992-2001 by ERF1_2 Watershed.
% Developed from 1992-2001
Figure 3-3. EPA Region 2: Percent urban change 1992-2001 by ERF1_2 Watershed.
Page 3-6
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Section 3: Data Collection
% Developed from 1992-2001
0,01% -0.1%
0 11% -0.5%
0.51% -2%
> 2%
] Miles
Figure 3-4. EPA Region 3: Percent urban change 1992-2001 by ERF1_2 Watershed.
% Developed from 1992-2001
=0.01%
0.01%-0.1%
0.11%-0.5%
0.51%-2%
> 2% 22°
Figure 3-5. EPA Region 4: Percent urban change 1992-2001 by ERF 12 Watershed.
Page 3-7
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Section 3: Data Collection
'h Developed from 1992-2001
0.01%-0.1%
0.11%-0.5%
0.51%-2%
I = 2%
] Miles
Figure 3-6. EPA Region 5: Percent urban change 1992-2001 by ERF1_2 Watershed.
% Developed from 1992-2001
0.01% -0.1%
0.11% -0.5%
0.51% - 2%
> 2%
Figure 3-7. EPA Region 6: Percent urban change 1992-2001 by ERF 12 Watershed.
Page 3-8
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Section 3: Data Collection
% Developed from 1992-2001
0.01%-0.1%
0.11%-0.5%
0.51%-2%
> 2%
H Miles
Figure 3-8. EPA Region 7: Percent urban change 1992-2001 by ERF1_2 Watershed.
% Developed from 1992-2001
Figure 3-9. EPA Region 8: Percent urban change 1992-2001 by ERF 12 Watershed.
Page 3-9
-------
Section 3: Data Collection
% Developed from 1992-2001
0.01% -0.1%
0.11% -0.5%
0.51% -2%
^B > 2%
Figure 3-10. EPA Region 9: Percent urban change 1992-2001 by ERF1 2 Watershed.
% Developed from 1992-2001
Figure 3-11. EPA Region 10: Percent urban change 1992-2001 by ERF 12 Watershed.
Estimates of the amount of construction activity occurring in each state based on NLCD data
were used as a basis for calculating state-level compliance costs. NLCD data was also used to
estimate the amount of construction activity occurring in each of the watersheds in the United
States on the basis of the EPA RF1 cataloging system (discussed below). RF1-level data (along
with other data sources) were used to estimate the quantity of construction activities and the
associated pollutant loads occurring in each RF1 and to link these loads to stream reaches for
Page 3-10
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Section 3: Data Collection
modeling of water quality improvements and benefits estimates. Because NLCD data does not
exist for Alaska, Hawaii, or the U.S. territories, EPA's analysis does not consider costs or
pollutant loading reductions for these areas. Detailed definitions and discussion of the NLCD
1992/2001 Retrofit Product is presented in Appendix E. DCN 43097 in the Administrative
Record provides an index to the NLCD-related analyses conducted for the proposed rule.
3.5.1.2. River Reach File Data
An option for summarizing national land cover change in drainage area units is to use EPA's
RF1 for the CONUS. RF1 is a vector database of approximately 700,000 miles of streams and
open waters in the CONUS. EPA and states use it extensively, and the U.S. Fish and Wildlife
Service and the National Weather Service (NWS) have used it for many years. EPA prepared
RF1 in 1982 from National Oceanic and Atmospheric Administration (NOAA) aeronautical
charts having a scale of 1:500,000. These charts provided the best nationwide hydrographic
coverage available on a single scale at that time. They include all hydrography shown on USGS
maps having a scale of 1:250,000 with extensive additions, corrections, and improvements in
detail made by NOAA from aerial photography and satellite imagery. In the 1980s, EPA used
RF1 for performing water quality modeling on whole river basins for all the hydrologic regions
in the CONUS. In this role, it was used to provide national assessments and overviews of water
quality and to provide the foundation for a nationwide, stratified, sampling frame for performing
statistical summaries of modeled and measured water quality on all surface waters of the
CONUS.
A consistent, national scale watershed data set was prepared to enhance the RF1 hydrology data
set. This watershed data set, the Enhanced River Reach File 1.2 (ERF1), was designed to be a
digital database of river reaches capable of supporting regional and national water-quality and
river-flow modeling and transport investigations in the water-resources community. ERF1 has
been used at the USGS to support interpretations of stream water-quality monitoring network
data. In these analyses, the reach network has been used to determine flow pathways between the
sources of point and nonpoint pollutants and downstream water-quality monitoring locations in
support of predictive water-quality models of stream nutrient transport.
The Enhanced River Reach File 2.0 (ERF1_2) expands on ERF1 and includes the incremental
and total drainage area founded on the 1-kilometer (km) elevation data for North America (Nolan
2002). Previous estimates of the water time-of-travel were recomputed for reaches with water
quality monitoring sites that included two reaches. The mean flow and velocity estimates for
these split reaches are based on previous estimation methods (Alexander et al. 1999) and are
unchanged in ERF1_2. Drainage area calculations provide data used to estimate the contribution
of a given nutrient to the outflow. ERF1 2 contains 67,171 watersheds with a minimum size of
0 0
247 acres (1 square km [km ]) and an average size of 30,182 acres (122 km ).
EPA used the ERF1_2 as the foundation for summarizing land cover change and in drainage area
units (or watersheds) and for SPARROW (Spatially Referenced Regressions [of nutrient
transport] on Watershed) modeling. Within the context of a geographic information system
(GIS), SPARROW estimates the proportion of watersheds in the CONUS with outflow
concentrations of several nutrients, including total nitrogen and total phosphorus, (Smith et al.
Page 3-11
-------
Section 3: Data Collection
1997). EPA modified SPARROW to model changes in sediment flux in the RF1 network to
evaluate potential benefits of regulatory options.
3.5.2. NPDES PERMIT NOTICE OF INTENT DATA
EPA used CGP Notice of Intent (NOT) records to characterize construction activity by project
type and project size for subsequent analysis of costs and pollutant loading reductions. Using
NOT data, EPA broadly characterized the construction industry into three land use types
(residential construction, nonresidential construction, and road/highway construction). EPA has
NOT data for approximately 138,000 permit applications, containing data from 38 states for
construction activities occurring primarily between the mid-1990s and 2006. Depending on the
state, the number of NOT records available ranged from fewer than 10 to more than 10,000. The
data are available either from a database of permits processed directly by EPA (referred to as the
EPA_NOI database) or per-state databases obtained independently. In general, the NOT records
are sufficiently similar to allow pooling of all sources regardless of whether EPA or an
individual state is the permit processing entity. While the NOT data are useful for characterizing
construction activities into different project types and different project sizes, EPA did not find
the NOT data useful as a national data set to estimate the amount of construction occurring. This
is because the NOT data obtained by EPA is not national in coverage. EPA's analysis of the NOT
data can be found in Appendix C, Analysis of Construction Industry Trends using Notice of
Intent Records. The NOI permit characterization data is DCN 43093 and the NOI Model Site
Assessment is DCN 43094 in the Administrative Record.
3.5.3. CLIMATIC/RAINFALL DATA
3.5.3.1. NOAA National Weather Service Precipitation Frequency Data Server
Variations in rainfall depth and intensity are important factors in determining erosion rates,
sediment discharges, pollutant load reductions, and control technology costs for construction
sites. For the pollutant loading analysis, EPA used a case study approach based on 11 indicator
cities. EPA selected representative areas in each of the 10 EPA Regions to be used as a point
estimate for the entire region. EPA generally selected the urban area within each region with the
greatest rate of development, on the basis of EPA's analysis of land use change from the NLCD
analysis. EPA selected one metropolitan area in each of the 10 EPA Regions, with the exception
of Region 10. In Region 10, EPA selected two indicator cities because the two areas with the
greatest rate of development (Boise City, Idaho, and Seattle, Washington) have very different
rainfall patterns. For each of these 11 indicator cities, EPA obtained detailed rainfall data and
rainfall summaries. EPA also obtained detailed soils data for each of these 11 areas. The 11
indicator cities are identified in Table 3-2.
EPA's costing analysis used state-specific rainfall estimates for determining stormwater runoff
rates and volumes and for determining sediment basins and treatment system sizing. EPA
identified one major city within each state to serve as an indicator for the entire state. EPA
obtained rainfall summary data for each of these cities for using as a basis for determining
expected runoff rates and rainfall volumes for costing of technologies.
Page 3-12
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Section 3: Data Collection
Table 3-2. EPA Region Indicator Cities
EPA Region
1
2
3
4
5
6
7
8
9
10
Indicator city
Manchester, NH
Albany, NY
Washington, DC, VA, and MD
Atlanta, GA
Chicago, IL IN
Dallas, Fort Worth, and Arlington, TX
Kansas City, MO and KS
Denver and Aurora, CO
Las Vegas, NV
Boise City, ID, and Seattle, WA
Precipitation data was gathered and analyzed using the NOAA NWS Precipitation Frequency
Data Server (PFDS). The Hydrometeorological Design Studies Center (FfDSC) within the Office
of Hydrologic Development of the NWS is in an ongoing process of updating its precipitation
frequency estimates, which are available in NOAA Atlas 14 format. At the time of this writing,
only a portion of the United States had been updated into this format (NWS 2008). Atlas 14
supercedes precipitation frequency estimates contained in previous NWS publications. The
updates are based on more recent and extended data sets, currently accepted statistical
approaches, and improved spatial interpolation and mapping techniques. A complete list of NWS
publications is at http://www.nws.noaa.gov/ohd/hdsc/currentpf.htm.
NOAA Atlas 14 contains precipitation frequency estimates with associated confidence limits for
the United States for 5-minute through 60-day durations at average recurrence intervals of 1-year
through 1,000-year. The estimates are based on the analysis of annual maximum series and then
converted to partial duration series results. The Atlas 14 rainfall data results used in this study
are shown in Attachment D to Appendix D.
For the states not currently updated by NOAA Atlas 14, the rainfall-frequency values for
selected durations were estimated using a series of maps presented in the older NWS
publications. The data for the remainder of the Western United States were estimated by using
NOAA Atlas 2, Precipitation Frequency Atlas of the Western United States (NOAA 1973),
which are generalized maps presented for 6- and 24-hour point precipitation for the return
periods of 2, 5, 10, 25, 50, and 100 years. Atlas 2 is published in separate volumes for each of the
states. Similarly, the maps presented in the corresponding Technical Paper were used for the
remainder of the Eastern United States and Hawaii. (Alaska was not included in this study
because EPA lacked sufficient data on the annual amount of construction activities in Alaska).
Precipitation frequency results not generated by Atlas 2 or Technical Paper maps are presented in
Attachment E to Appendix D. The rainfall depths were estimated by identifying the target city on
the Atlas 2 or Technical Paper map and linearly approximating the rainfall value. For example, if
a city fell between a depth of 4.5 and 5 inches and the city was approximately 20 percent of the
map distance from the 5-inch line, a rainfall depth of 4.9 inches was estimated. Note that the
maps provided data for depth only. Intensity estimates were calculated by dividing the duration
Page 3-13
-------
Section 3: Data Collection
(e.g., 6- or 24-hour) by the depth. Additionally, Atlas 2 depths were converted from tenths of an
inch to inches.
To analyze the percent of total construction site runoff captured and treated for various
regulatory options, EPA obtained hourly precipitation data for each indicator city. EPA obtained
30 years of hourly rainfall data from Earthlnfo Version 2.31 (www.earthinfo.com). Earthlnfo
provides National Climatic Data Center (NCDC) meteorological data in an easy-to-use format
from which precipitation data can be extracted. From the 7,000 NCDC gages available, EPA
generally used data collected at an airport in or adjacent to each indicator city. In general, EPA
analyzed data for the period between the mid-1970s and mid-2000s.
Table 3-3 summarizes the state-specific rainfall data EPA used in its analyses. It is important to
note that EPA's analysis does not distinguish between precipitation that falls as rain from
precipitation that falls as snow or ice.
3.5.3.2. Parameter Elevation Regressions on Independent Slopes Model (PRISM)
Although EPA is not proposing an option that contains an annual precipitation cutoff, EPA did
evaluate several scenarios that included annual precipitation as applicability criteria for the
turbidity option. EPA's analyses of rainfall-based scenarios required an estimate of the total
annual precipitation for each RF1 watershed. PRISM is a climate mapping system that was used
to estimate the annual acres that would be exempt from the regulatory scenarios given various
rainfall cut-offs. For each RF1 watershed, the average annual rainfall amount was obtained from
the 1-km resolution United States Average Monthly or Annual Precipitation (1971-2000)
PRISM Group raster data coverage (PRISM Group 2006). RF1 watershed boundaries were used
to summarize the PRISM Group average annual rainfall values, and each RF1 was assigned a
value by spatially averaging contributing raster data. Using PRISM GIS layers of average annual
precipitation along with RF1-level estimates of annual acres of new construction, EPA was able
to estimate acres that would be in-scope for regulations given various average annual
precipitation cutoffs. Figure 3-12 shows average annual precipitation for the CONUS from the
PRISM data. Table 3-4 summarizes percent of new development that would be subject to
regulation for various annual precipitation cutoffs. Table 3-5 summarizes these results as acres of
new development Additional information on the PRISM data is in Appendix D.
Page 3-14
-------
Table 3-3. Rainfall Summary Data for Indicator Cities
as
era
re
in
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
City
Montgomery
Phoenix
Little Rock
Sacramento
Denver
Hartford
Dover
Tallahassee
Atlanta
Honolulu
Boise
Chicago
Indianapolis
Des Moines
Kansas City
Frankfort
Baton Rouge
Augusta
Baltimore
Boston
Lansing
St. Paul
Jackson
Kansas City
Helena
Lincoln
Las Vegas
Manchester
Hightstown
Average
annual
precipitation
(inches)
49
8
48
18
13
44
43
62
51
18
11
33
40
32
37
45
59
42
42
42
30
29
52
37
12
28
4
40
47
2-year, 24-
hour storm
depth
(inches)
4.50
1.40
4.10
2.00
2.00
3.10
3.26
4.75
3.70
4.25
1.20
2.85
2.95
3.25
3.50
3.00
5.25
2.80
3.16
3.10
2.40
2.75
4.45
3.45
1.30
3.00
1.00
2.80
3.31
10-year, 24-
hour storm
depth
(inches)
6.5
2.14
6.05
3
3
4.8
5.08
7.4
5.5
7.8
1.8
4.29
4.13
4.7
5.2
4.34
8.2
4.25
4.85
4.5
3.6
4.2
6.7
5.3
2.1
4.8
1.62
4.3
5.07
25-year, 24-
hour storm
depth
(inches)
7.6
2.59
7
3.5
3.8
5.5
6.36
8.5
6.5
8.9
2.2
5.25
4.83
5.5
6.1
5.23
9.1
4.9
6.08
5.5
4.2
4.7
7.8
6
2.4
5.4
1.96
5
6.3
10-year, 6
hour storm
depth
(inches)
4.60
1.57
4.35
1.70
2.30
3.25
3.44
5.25
4.20
4.80
1.20
3.30
3.12
3.54
3.90
3.09
5.75
2.90
3.32
3.30
2.70
3.10
4.70
3.85
1.10
3.52
1.29
3.20
3.55
-------
as
era
re
O\
State
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
City
Santa Fe
Albany
Charlotte
Bismarck
Columbus
Oklahoma City
Salem
Philadelphia
Providence
Columbia
Pierre
Nashville
Fort Worth
Salt Lake City
Montpelier
Arlington
Seattle
Charleston
Madison
Cheyenne
San Juan
Washington
Average
annual
precipitation
(inches)
15
37
43
16
38
33
41
42
45
45
16
46
33
15
34
40
35
43
31
15
51
42
2-year, 24-
hour storm
depth
(inches)
1.54
2.90
3.34
1.90
2.62
3.70
2.50
3.23
3.20
3.62
2.25
3.37
3.90
1.40
2.40
3.11
2.00
2.56
2.80
1.60
4.26
3.16
10-year, 24-
hour storm
depth
(inches)
2.22
4
4.86
3.25
3.73
5.8
3.5
4.8
4.8
5.28
3.5
4.7
6.3
1.9
3.7
4.78
3
3.55
4.1
2.4
6.76
4.85
25-year, 24-
hour storm
depth
(inches)
2.62
5.9
5.76
3.75
4.44
6.9
4
5.85
5.7
6.39
4.1
5.53
7.4
2.21
4.25
5.98
3.4
4.16
4.75
2.8
8.29
6.07
10-year, 6
hour storm
depth
(inches)
1.77
3.10
3.54
2.50
2.80
4.25
2.90
3.38
3.40
3.85
2.75
3.31
4.55
1.27
2.70
3.29
1.40
2.56
3.15
1.90
4.42
3.32
-------
Section 3: Data Collection
Avg Annual Precip (in)
Figure 3-12. Average Annual Precipitation in the CONUS from PRISM.
Page 3-17
-------
Table 3-4. Percent of Developed Acres In-Scope for Various Annual Precipitation Amounts
Annual precipitation (in inches) =»
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
5
10
15
20
25
30
35
40
45
50
NOT ANALYZED
100.0%
96.8%
100.0%
98.9%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
43.7%
100.0%
83.9%
93.9%
100.0%
100.0%
100.0%
100.0%
100.0%
13.1%
100.0%
56.9%
62.4%
100.0%
100.0%
100.0%
100.0%
100.0%
5.2%
100.0%
32.0%
8.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.4%
100.0%
11.0%
1.7%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
100.0%
8.0%
0.9%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
100.0%
6.8%
0.5%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
100.0%
5.8%
0.2%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
97.4%
4.1%
0.0%
100.0%
45.5%
100.0%
100.0%
99.4%
0.0%
64.6%
3.0%
0.0%
60.3%
0.0%
99.5%
71.3%
NOT ANALYZED
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
93.7%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
99.8%
29.5%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
38.9%
17.3%
100.0%
100.0%
100.0%
90.4%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
99.9%
100.0%
100.0%
13.7%
9.7%
100.0%
100.0%
100.0%
72.7%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
88.3%
100.0%
100.0%
5.6%
6.0%
100.0%
100.0%
91.0%
58.9%
100.0%
100.0%
100.0%
100.0%
100.0%
96.3%
46.6%
100.0%
100.0%
2.4%
1.8%
97.8%
100.0%
41.0%
39.2%
100.0%
100.0%
100.0%
100.0%
100.0%
15.6%
0.0%
100.0%
99.9%
1.3%
0.6%
12.2%
51.4%
0.0%
10.4%
100.0%
100.0%
85.7%
97.8%
100.0%
0.0%
0.0%
100.0%
71.2%
0.9%
0.3%
4.0%
13.2%
0.0%
0.3%
85.3%
100.0%
42.0%
25.0%
96.9%
0.0%
0.0%
100.0%
11.9%
0.5%
0.0%
0.0%
0.0%
0.0%
0.0%
29.5%
100.0%
2.4%
0.3%
1.2%
0.0%
0.0%
100.0%
0.1%
0.0%
.
o
s
-------
Annual precipitation (in inches) =»
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Nation
5
100.0%
97.1%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
99.8%
10
100.0%
25.8%
100.0%
100.0%
87.2%
100.0%
100.0%
100.0%
100.0%
100.0%
96.9%
100.0%
100.0%
100.0%
100.0%
100.0%
99.3%
94.7%
100.0%
100.0%
80.0%
100.0%
100.0%
75.9%
100.0%
95.9%
15
99.7%
9.5%
100.0%
100.0%
28.3%
100.0%
100.0%
96.9%
100.0%
100.0%
71.3%
100.0%
100.0%
100.0%
100.0%
100.0%
97.4%
63.4%
100.0%
100.0%
72.2%
100.0%
100.0%
34.7%
100.0%
89.7%
20
71.9%
2.1%
100.0%
100.0%
3.4%
100.0%
100.0%
10.0%
100.0%
90.8%
63.9%
100.0%
100.0%
100.0%
55.1%
100.0%
88.8%
38.4%
100.0%
100.0%
68.6%
100.0%
100.0%
7.8%
100.0%
82.2%
25
47.1%
0.2%
100.0%
100.0%
0.6%
100.0%
100.0%
0.0%
100.0%
87.1%
57.2%
100.0%
100.0%
100.0%
7.8%
100.0%
79.0%
12.3%
100.0%
100.0%
66.1%
100.0%
100.0%
3.1%
100.0%
77.2%
30
23.1%
0.0%
100.0%
100.0%
0.1%
100.0%
100.0%
0.0%
100.0%
72.6%
55.7%
100.0%
100.0%
100.0%
0.0%
100.0%
70.8%
2.9%
100.0%
100.0%
65.1%
100.0%
99.2%
1.7%
100.0%
73.6%
35
0.0%
0.0%
100.0%
100.0%
0.0%
93.0%
100.0%
0.0%
98.0%
55.6%
51.3%
99.9%
100.0%
100.0%
0.0%
100.0%
55.8%
0.4%
99.6%
100.0%
62.5%
100.0%
3.0%
1.0%
100.0%
64.2%
40
0.0%
0.0%
97.6%
100.0%
0.0%
67.1%
99.7%
0.0%
34.5%
31.6%
50.0%
85.9%
100.0%
100.0%
0.0%
100.0%
32.4%
0.1%
77.4%
93.3%
57.1%
78.5%
0.0%
0.2%
100.0%
50.7%
45
0.0%
0.0%
66.1%
86.5%
0.0%
28.2%
97.6%
0.0%
0.1%
11.5%
41.5%
36.8%
100.0%
100.0%
0.0%
97.8%
25.1%
0.0%
45.2%
41.4%
43.3%
37.6%
0.0%
0.1%
0.0%
39.7%
50
0.0%
0.0%
3.7%
13.9%
0.0%
7.9%
20.4%
0.0%
0.0%
7.1%
35.1%
3.7%
10.0%
37.0%
0.0%
91.6%
12.6%
0.0%
24.4%
4.0%
32.4%
9.5%
0.0%
0.0%
0.0%
25.5%
.
o
s
-------
Table 3-5. Developed Acres In-Scope for Various Annual Precipitation Amounts
Annual precipitation (in inches) =»
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
5
10
15
20
25
30
35
40
45
50
NOT ANALYZED
14,503
13,191
8,486
27,125
15,830
1,006
833
38,064
32,591
14,503
5,960
8,486
22,998
14,858
1,006
833
38,064
32,591
14,503
1,783
8,486
15,595
9,879
1,006
833
38,064
32,591
14,503
713
8,486
8,777
1,267
1,006
833
38,064
32,591
14,503
59
8,486
3,013
271
1,006
833
38,064
32,591
14,503
6
8,486
2,196
141
1,006
833
38,064
32,591
14,503
2
8,486
1,870
80
1,006
833
38,064
32,591
14,503
8,486
1,596
37
1,006
833
38,064
32,591
14,503
8,262
1,133
4
1,006
379
38,064
32,591
14,420
5,481
826
606
37,860
23,232
NOT ANALYZED
5,674
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
6,456
5,315
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
6,441
1,675
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
2,514
983
20,502
12,372
10,094
20,378
9,976
12,843
4,496
6,535
3,320
22,495
9,325
11,856
13,550
884
549
20,502
12,372
10,094
16,388
9,976
12,843
4,496
6,535
3,320
22,495
8,241
11,856
13,550
362
339
20,502
12,372
9,183
13,271
9,976
12,843
4,496
6,535
3,320
21,652
4,353
11,856
13,550
154
105
20,060
12,372
4,142
8,832
9,976
12,843
4,496
6,535
3,320
3,511
11,856
13,533
83
34
2,505
6,355
2,354
9,976
12,843
3,854
6,389
3,320
11,856
9,643
58
19
823
1,634
56
8,513
12,843
1,888
1,631
3,219
11,856
1,613
35
2
2,943
12,843
108
18
41
11,856
12
3
.
o
s
-------
Annual precipitation (in inches) =»
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Nation
5
6,078
7,916
1,786
4,269
4,670
7,721
18,738
6,537
17,398
16,730
7,285
16,003
377
16,169
8,310
13,089
61,304
8,389
569
15,146
12,792
3,513
7,569
2,843
66
588,934
10
6,078
2,100
1,786
4,269
4,072
7,721
18,738
6,537
17,398
16,730
7,059
16,003
377
16,169
8,310
13,089
60,865
7,943
569
15,146
10,239
3,513
7,569
2,158
66
565,469
15
6,060
779
1,786
4,269
1,321
7,721
18,738
6,333
17,398
16,730
5,191
16,003
377
16,169
8,308
13,089
59,721
5,317
569
15,146
9,234
3,513
7,569
988
66
529,230
20
4,371
168
1,786
4,269
158
7,721
18,738
654
17,398
15,190
4,656
16,003
377
16,169
4,577
13,089
54,455
3,219
569
15,146
8,778
3,513
7,569
221
66
484,709
25
2,861
16
1,786
4,269
30
7,721
18,738
17,398
14,580
4,164
16,003
377
16,169
650
13,089
48,440
1,034
569
15,146
8,453
3,513
7,569
88
66
455,135
30
1,405
3
1,786
4,269
4
7,721
18,738
17,398
12,146
4,060
16,003
377
16,169
13,089
43,421
244
569
15,146
8,327
3,513
7,510
48
66
434,241
35
1
2
1,786
4,269
7,180
18,738
17,059
9,309
3,738
15,994
377
16,169
13,089
34,231
31
567
15,146
7,994
3,513
231
29
66
378,617
40
1,744
4,269
5,179
18,687
5,997
5,282
3,645
13,745
377
16,169
13,089
19,850
9
440
14,133
7,301
2,758
5
66
299,046
45
1,180
3,691
2,174
18,283
21
1,916
3,021
5,888
377
16,169
12,799
15,409
257
6,268
5,533
1,321
3
234,379
50
66
592
612
3,828
1,191
2,558
589
38
5,980
11,995
7,717
139
599
4,146
335
-
150,635
.
o
s
-------
Section 3: Data Collection
3.5.4. SOILS DATA
The variation in soil types found in the United States is a significant factor in estimating
sediment discharges, pollutant load reductions, and stormwater pollution prevention costs for
construction sites. EPA used two discrete soils data sets in support of its analysis. For the loading
analysis, EPA used a case study approach using the 11 indicator cities described above. For this
analysis, EPA used soil coverage data provided in the State Soil Geographic Database
(STATSGO) (Wolock 1997 and USDA 2007). STATSGO component and layer tables were
accessed through the Pennsylvania State University's active archive
(http://www.soilinfo.psu.edu/index.cgi?soil_data&index.html).
The data available in STATSGO are valuable to EPA because they provide enough detail to
evaluate broad trends in soil distribution but are still generalized sufficiently to permit analysis of
many acres. It is EPA's expectation that evaluating soil over large geographic areas (the sum of
which is much larger than the approximate 600,000 acres developed annually) will produce a
representative sample sufficient for analyzing loads expected to occur for the C&D industry.
The geographic limits of the STATSGO soil coverage evaluated were determined by
superimposing indicator city urban area boundariesfrom the U.S. Census Bureau's 2000
Urbanized Areas Cartographic Boundary Files (U.S. Census Bureau 2000)on intersecting RF1
watersheds. The resulting list of RF1 watersheds intersecting the rapidly developing indicator
city urban areas was used to spatially identify underlying STATSGO soil coverage Map Unit
Identifiers (MUIDs). Last, soil data associated with the surface soil layer within the selected
MUIDs were extracted from STATSGO to produce the suite of data evaluated for each indicator
city.
The soil data extracted from STATSGO and used in the loading analysis included the highest
and lowest reported land slopes, the erosivity ("K") factor used in the Revised Universal Soil
Loss Equation (RUSLE), the soil hydrologic group, and soil texture characteristics (i.e., the
percent of soil passing through various sieve sizes). Additional information on this analysis is in
Section 10.2.
For the costing analysis and for determining acres within each state that would be subject to the
proposed regulation for various soil percent clay contents, EPA used a national GIS data layer on
soil characteristics (see http://www.soilinfo.psu.edu/index.cgi7soil data&conus). Using this data
set, along with RF1-level estimates of the amount of construction activity occurring, EPA
determined the amount of developed acres annually that would be subject to the turbidity
standard for various soil clay contents (where clay is defined as being particles smaller than 2
microns in diameter) at the RF1 and state level. EPA used only the surface soil layer as a basis
for this analysis. Figure 3-13 illustrates surface soil percent clay content for each RF1 within the
CONUS and presents the geographic basis for determining areas in-scope for the regulatory
options evaluated. Additional information on soils data used for the costing analysis is in Section
9.
Page 3-22
-------
Section 3: Data Collection
RF1 Watershed
% Clay (Layer 1)
10-10
I | 10.1 - 15
I [15.1-20
I 120.1 -25
I 125.1 -100
Figure 3-13. Surface Soil Layer Percent Clay Content.
3.5.5. VENDOR DATA FOR ACTIVE TREATMENT SYSTEMS
EPA compiled and evaluated information from vendors on treatment technologies that could be
used in setting numeric standard discharge limits for stormwater runoff from construction sites.
EPA conducted an Internet-based search and placed telephone calls to several vendors to gather
data on available treatment technologies, costs, and performance (see Document Control
Numbers 43000 through 43011 and Document Control Number 43081 in the administrative
record for vendor-specific information and fact sheets). EPA also received unsolicited e-mails
with data from vendors.
3.5.6. RAINFALL AND RUNOFF EROSIVITY FACTOR
EPA used a GIS data layer for the RUSLE R-factor to determine acres in-scope for various
annual R-factor values. The R-factor (USDA 1997) is an indicator of rainfall energy and
intensity and varies seasonally across the United States. EPA uses this data for determining
whether small construction sites can qualify for the Low Erosivity Waiver (LEW) contained in
the NPDES Phase II stormwater regulations. EPA has an online tool that can be used to
determine if sites qualify for the LEW (see
http://cfpub.epa.gov/npdes/stormwater/lew/lewcalculator.cfm). By combining the R-factor data
with the RF1 data on acres of new development, EPA was able to determine acres in-scope for
various annual R-factor values. Figure 3-14 shows annual R-factor values for the CONUS and
Page 3-23
-------
Section 3: Data Collection
Tables 3-6 and 3-7 show percent and quantity of developed acres that would be in-scope for
various annual R-factor values.
3.5.7. HYDROLOGIC SOIL GROUPS
EPA used the STATSGO GIS data layer to determine the percent of each hydrologic soil group
by state. Hydrologic soil groups were used to estimate runoff coefficients for an indicator city
within each state. Table 3-8 shows the percent of each hydrologic soil group by state.
Page 3-24
-------
era
n
w
N>
C/l
] Miles
Figure 3-14. Annual R-Factor Values for CONUS.
-------
Table 3-6. Percent Developed Acres In-Scope for Various Annual R-Factor Values
R-Factor =»
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
<10
<20
<30
<40
<50
<60
<70
<80
<90
<100
NOT ANALYZED
100.0%
98.7%
100.0%
97.6%
82.5%
100.0%
100.0%
100.0%
100.0%
100.0%
77.6%
100.0%
70.8%
76.0%
100.0%
100.0%
100.0%
100.0%
100.0%
44.6%
100.0%
58.3%
62.7%
100.0%
100.0%
100.0%
100.0%
100.0%
14.4%
100.0%
40.7%
24.0%
100.0%
100.0%
100.0%
100.0%
100.0%
10.8%
100.0%
15.9%
18.9%
100.0%
100.0%
100.0%
100.0%
100.0%
4.9%
100.0%
11.2%
4.8%
100.0%
100.0%
100.0%
100.0%
100.0%
3.8%
100.0%
8.9%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.5%
100.0%
5.9%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.1%
100.0%
4.4%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.1%
100.0%
3.4%
0.0%
100.0%
100.0%
100.0%
100.0%
NOT ANALYZED
8.4%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
76.7%
100.0%
1.0%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
28.9%
100.0%
0.0%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
7.1%
99.9%
0.0%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
98.8%
0.0%
0.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
88.7%
0.0%
0.0%
100.0%
100.0%
100.0%
99.9%
100.0%
100.0%
94.7%
100.0%
100.0%
100.0%
100.0%
100.0%
100.0%
0.0%
79.3%
0.0%
0.0%
100.0%
100.0%
100.0%
97.7%
100.0%
100.0%
85.8%
100.0%
100.0%
99.6%
93.2%
100.0%
100.0%
0.0%
74.2%
0.0%
0.0%
100.0%
100.0%
100.0%
96.2%
100.0%
100.0%
63.4%
100.0%
100.0%
71.5%
80.4%
100.0%
100.0%
0.0%
70.9%
0.0%
0.0%
100.0%
100.0%
100.0%
94.2%
100.0%
100.0%
29.9%
100.0%
100.0%
40.9%
54.9%
100.0%
100.0%
0.0%
64.8%
0.0%
0.0%
100.0%
100.0%
100.0%
89.4%
100.0%
100.0%
0.9%
100.0%
100.0%
13.3%
49.0%
100.0%
100.0%
0.0%
56.6%
0.0%
-------
era
re
R-Factor =»
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
<10
100.0%
100.0%
78.2%
100.0%
100.0%
100.0%
100.0%
100.0%
82.9%
100.0%
100.0%
100.0%
100.0%
100.0%
98.8%
37.9%
100.0%
100.0%
70.7%
100.0%
100.0%
42.9%
100.0%
94.6%
<20
100.0%
100.0%
63.4%
100.0%
100.0%
100.0%
100.0%
100.0%
54.5%
100.0%
100.0%
100.0%
100.0%
100.0%
98.5%
0.0%
100.0%
100.0%
62.3%
100.0%
100.0%
33.7%
100.0%
90.8%
<30
100.0%
100.0%
29.6%
100.0%
100.0%
95.6%
100.0%
100.0%
52.0%
100.0%
100.0%
100.0%
99.1%
100.0%
98.5%
0.0%
100.0%
100.0%
61.6%
100.0%
100.0%
5.9%
100.0%
88.3%
<40
100.0%
100.0%
9.0%
100.0%
100.0%
90.9%
100.0%
100.0%
50.8%
100.0%
100.0%
100.0%
96.8%
100.0%
98.0%
0.0%
100.0%
100.0%
60.0%
100.0%
100.0%
1.0%
100.0%
85.3%
<50
100.0%
100.0%
3.2%
100.0%
100.0%
68.9%
100.0%
100.0%
48.4%
100.0%
100.0%
100.0%
93.2%
100.0%
97.8%
0.0%
100.0%
100.0%
43.0%
100.0%
100.0%
0.0%
100.0%
83.0%
<60
100.0%
100.0%
0.1%
99.7%
100.0%
25.7%
100.0%
100.0%
42.5%
100.0%
100.0%
100.0%
85.3%
100.0%
96.6%
0.0%
100.0%
100.0%
34.3%
100.0%
100.0%
0.0%
100.0%
81.1%
<70
100.0%
100.0%
0.0%
92.3%
100.0%
7.3%
100.0%
98.9%
31.6%
100.0%
100.0%
100.0%
57.9%
100.0%
95.3%
0.0%
100.0%
100.0%
27.6%
100.0%
100.0%
0.0%
100.0%
79.4%
<80
97.7%
100.0%
0.0%
53.4%
100.0%
0.0%
100.0%
97.1%
25.5%
100.0%
100.0%
100.0%
32.2%
100.0%
94.2%
0.0%
55.5%
100.0%
20.6%
100.0%
99.9%
0.0%
100.0%
76.2%
<90
88.1%
100.0%
0.0%
37.2%
100.0%
0.0%
100.0%
96.7%
22.9%
97.7%
100.0%
100.0%
16.9%
100.0%
91.9%
0.0%
28.6%
100.0%
13.2%
100.0%
84.7%
0.0%
100.0%
73.0%
<100
37.3%
100.0%
0.0%
26.1%
100.0%
0.0%
91.8%
92.0%
20.1%
90.7%
100.0%
100.0%
10.5%
100.0%
89.7%
0.0%
6.7%
100.0%
10.8%
100.0%
76.2%
0.0%
100.0%
69.9%
-------
Table 3-7. Developed Acres In-Scope for Various Annual R-Factor Values
R-Factor =»
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
<10
14,503
13,456
8,486
26,771
13,055
1,006
833
38,064
32,591
0
474
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
4,952
6,078
81
1,786
<20
14,503
10,571
8,486
19,406
12,036
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
1,864
6,078
0
1,786
<30
14,503
6,078
8,486
15,981
9,926
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
459
6,070
0
1,786
<40
14,503
1,962
8,486
11,155
3,796
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
0
6,006
0
1,786
<50
14,503
1,475
8,486
4,368
2,984
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
0
5,390
0
1,786
<60
14,503
672
8,486
3,071
761
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,520
9,976
12,843
4,255
6,535
3,320
22,495
9,331
11,856
13,550
0
4,821
0
1,786
<70
14,503
515
8,486
2,427
8
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
22,013
9,976
12,843
3,855
6,535
3,320
22,403
8,697
11,856
13,550
0
4,508
0
1,786
<80
14,503
72
8,486
1,612
0
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
21,673
9,976
12,843
2,852
6,535
3,320
16,091
7,498
11,856
13,550
0
4,310
0
1,744
<90
14,503
15
8,486
1,215
0
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
21,227
9,976
12,843
1,345
6,535
3,320
9,189
5,123
11,856
13,550
0
3,937
0
1,573
<100
14,503
15
8,486
943
0
1,006
833
38,064
32,591
0
0
20,502
12,372
10,094
20,147
9,976
12,843
40
6,535
3,319
2,999
4,569
11,856
13,550
0
3,439
0
667
>100
0
13,613
0
26,478
15,830
0
0
0
0
0
5,674
0
0
0
2,391
0
0
4,456
0
1
19,496
4,762
0
0
6,456
2,639
8,156
1,119
-------
R-Factor =»
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
National Total
% of Total
<10
4,269
3,650
7,721
18,738
6,537
17,398
16,730
6,041
16,003
377
16,169
8,310
13,089
60,550
3,176
569
15,146
9,045
3,513
7,569
1,220
0
66
557,879
95%
<20
4,269
2,961
7,721
18,738
6,537
17,398
16,730
3,968
16,003
377
16,169
8,310
13,089
60,390
0
569
15,146
7,967
3,513
7,569
959
0
66
535,462
91%
<30
4,269
1,383
7,721
18,738
6,251
17,398
16,730
3,791
16,003
377
16,169
8,239
13,089
60,384
0
569
15,146
7,880
3,513
7,569
169
0
66
520,950
88%
<40
4,269
422
7,721
18,738
5,944
17,398
16,730
3,700
16,003
377
16,169
8,040
13,089
60,102
0
569
15,146
7,679
3,513
7,569
28
0
66
503,076
85%
<50
4,269
149
7,721
18,738
4,504
17,398
16,730
3,522
16,003
377
16,169
7,742
13,089
59,943
0
569
15,146
5,494
3,513
7,569
1
0
66
489,744
83%
<60
4,269
3
7,700
18,738
1,682
17,398
16,727
3,095
16,003
377
16,169
7,088
13,089
59,232
0
569
15,146
4,381
3,513
7,569
0
0
66
478,595
81%
<70
4,269
0
7,124
18,738
477
17,398
16,540
2,299
16,003
377
16,169
4,815
13,089
58,416
0
569
15,146
3,534
3,513
7,569
0
0
66
468,389
79%
<80
4,269
0
4,124
18,738
0
17,398
16,242
1,858
16,003
377
16,169
2,678
13,089
57,742
0
316
15,146
2,634
3,513
7,560
0
0
66
449,748
76%
<90
4,269
0
2,873
18,738
0
17,398
16,172
1,668
15,638
377
16,169
1,403
13,089
56,326
0
163
15,146
1,683
3,513
6,409
0
0
66
430,576
73%
<100
4,269
0
2,012
18,738
0
15,975
15,384
1,465
14,508
377
16,169
872
13,089
54,971
0
38
15,146
1,382
3,513
5,770
0
0
66
412,348
70%
>100
0
4,670
5,709
0
6,537
1,423
1,346
5,820
1,495
0
0
7,438
0
6,333
8,389
531
0
11,410
0
1,799
2,843
0
0
177,563
30%
era
re
-------
Table 3-8. Hydrologic Soil Groups by State
era
re
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Hydrologic Soil Group
A
8.7%
4.7%
0.6%
10.9%
7.2%
9.1%
20.8%
18.1%
6.6%
4.4%
1.4%
3.5%
0.9%
3.8%
0.1%
1.7%
7.7%
10.0%
23.9%
29.0%
8.3%
2.3%
1.0%
2.9%
B
41.2%
38.6%
28.3%
32.2%
46.7%
41.1%
30.9%
6.3%
53.1%
46.8%
44.5%
32.6%
66.0%
58.0%
42.7%
14.4%
12.9%
38.6%
16.6%
28.7%
37.4%
32.3%
40.1%
39.5%
C
28.8%
17.2%
35.9%
18.4%
24.6%
35.9%
13.4%
8.6%
16.9%
23.1%
27.0%
41.8%
11.6%
19.5%
44.9%
28.9%
43.9%
26.4%
34.4%
12.9%
15.4%
38.6%
39.8%
27.2%
D
21.3%
39.5%
35.1%
38.5%
21.4%
13.9%
34.9%
67.0%
23.5%
25.7%
27.1%
22.1%
21.5%
18.7%
12.3%
55.1%
35.5%
25.0%
25.2%
29.4%
38.9%
26.9%
19.0%
30.4%
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Hydrologic Soil Group
A
31.9%
5.6%
17.1%
12.5%
5.6%
9.6%
7.9%
4.7%
0.6%
6.8%
5.2%
6.0%
15.3%
11.9%
2.9%
0.1%
5.1%
5.3%
4.9%
1.7%
6.6%
7.3%
14.4%
4.5%
B
53.6%
26.4%
24.8%
32.8%
41.9%
18.5%
48.8%
56.1%
16.8%
44.5%
32.1%
28.4%
35.7%
41.8%
45.2%
53.6%
27.2%
36.2%
18.0%
53.7%
53.4%
21.5%
46.8%
40.5%
C
3.0%
17.7%
41.4%
25.1%
16.5%
51.1%
16.5%
16.6%
54.6%
22.3%
37.1%
54.2%
32.4%
19.5%
11.5%
30.4%
24.5%
16.2%
54.3%
32.3%
24.2%
54.2%
18.1%
19.5%
D
11.5%
50.3%
16.6%
29.6%
36.0%
20.7%
26.8%
22.6%
28.0%
26.4%
25.6%
11.5%
16.5%
26.8%
40.4%
15.9%
43.2%
42.3%
22.8%
12.3%
15.8%
17.0%
20.7%
35.5%
-------
Section 3: Data Collection
3.6. REFERENCES
Alexander, R.B., J.W. Brakebill, R.E. Brew, and R.A. Smith. 1999. Enhanced River Reach File
1.2 (ERF1) (Online database). U.S. Department of the Interior, U.S. Geological Survey,
Reston, VA. .
MRLC (Multi-Resolution Land Characteristics Consortium). 1992 and 2001. National Land
Cover Database. U.S. Department of the Interior, U.S. Geological Survey, Land Cover
Institute, . Updated March 21, 2008.
Nolan, J.V., J.W. Brakebill, R.B. Alexander, and G.E. Schwarz. 2002. Enhanced River Reach
File 2.0 (ERF1_2) (Online database). U.S. Department of the Interior, U.S. Geological
Survey, Reston, VA.
Accessed or Updated?
NOAA (National Oceanic and Atmospheric Administration). 1973. Precipitation Frequency
Atlas of the Western United States. Vols. 1-3, 5, 9-11. U.S. Department of Commerce,
National Weather Service. Silver Spring, MD. Precipitation Frequency Data Server (PFDS).
. Updated October 29, 2008.
NWS (National Weather Service). 2008. Precipitation Frequency Data Server. National Oceanic
and Atmospheric Administration, National Weather Service, Office of Hydrologic
Development, Silver Spring, MD. .Updated March 4,
2008.
PRISM Group. 2006. United States Average Monthly or Annual Precipitation (1971-2000).
Oregon State University, Corvallis, OR. . Accessed March
2008.
Smith, R.A., G.E. Schwarz, and R.B. Alexander. 1997. Regional interpretation of water-quality
monitoring data. Water Resources Research 33(12):2781-2798.
U.S. Census Bureau. 2000. 2000 Urbanized Areas Cartographic Boundary Files. U.S. Census
Bureau, Washington, DC. . Accessed
January 2008.
USD A (U.S. Department of Agriculture). 2008. Watershed Boundary Dataset. U.S. Department
of Agriculture, National Resources Conservation Service, Washington, DC.
. Updated March 5, 2008.
USDA (U.S. Department of Agriculture). 2007. U.S. General Soil Map (STATSGO) (Database).
U.S. Department of Agriculture, Natural Resources Conservation Service, Washington, DC.
. Updated July 11, 2007.
USDA (U.S. Department of Agriculture). 1997. Predicting Soil Erosion by Water: A Guide to
Conservation Planning with the Revised Universal Soil Loss Equation (RUSLE), Agriculture
Handbook Number 703. U.S. Department of Agriculture, Agricultural Research Service.
January, 1997.
Page 3-31
-------
Section 3: Data Collection
USEPA (U.S. Environmental Protection Agency). 1982. Reach File Version 1.0 (RF1). U.S.
Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds,
Washington, DC. . Accessed January 2008.
USGS (U.S. Geological Survey). 2008. The SPARROW Surface Water-Quality Model: Theory,
Application and User Documentation, U.S. Geological Survey Techniques and Methods,
Book 6, Section B, Chapter 3. U.S. Geological Survey, Reston, VA.
Wolock, D.M. 1997. STATSGO soil characteristics for the conterminous United States: U.S.
Geological Survey Open-File Report 97-656. U.S. Geological Survey, Reston, VA.
. Accessed December 2007.
Page 3-32
-------
Section 4: Industry Profile
4. INDUSTRY PROFILE
4.1. INTRODUCTION
The construction industry is divided into three major subsectors: general building contractors,
heavy construction contractors, and special trade contractors. General contractors build
residential, industrial, commercial, and other buildings. Heavy construction contractors build
sewers, roads, highways, bridges, and tunnels. Special trade contractors typically provide
carpentry, painting, plumbing, and electrical services.
Because the proposed effluent guidelines are being developed to address water quality issues,
this document focuses on the construction subsectors most closely associated with land-
disturbing activities. General contractors and heavy construction establishments are by definition
the most likely to conduct activities that could affect water resources. Note, however, that for
individual projects, responsibility for land-disturbing activities and potential effects on water
quality might not be obvious because general contractors often subcontract all or some of the
actual construction work. Hence, the following subsections describe the subsector categories
most likely to be responsible for land-disturbing activities at the national level.
The construction and development (C&D) industry is classified in the 2007 North American
Industry Classification System (NAICS) under Sector 23, Construction (U.S. Census Bureau
2008a). NAICS is the system used for classifying industry establishments by type of economic
activity, which replaced the U.S. Standard Industrial Classification (SIC) system.
The construction sector comprises establishments primarily engaged in constructing buildings or
engineering projects (e.g., highways and utility systems). Establishments primarily engaged in
preparing sites for new construction and establishments primarily engaged in subdividing land
for sale as building sites also are included in this sector (U.S. Census Bureau 2008a).
Construction work done may include new work, additions, alterations, or maintenance and
repairs. Activities of these establishments generally are managed at a fixed place of business, but
they usually perform construction activities at multiple project sites. Establishments identified as
construction-management firms are also included in the sector. The construction sector is divided
into three types of activities or subsectors as described below (from U.S. Census Bureau 2008a):
Subsector 236 - Construction of Buildings
This subsector comprises establishments of the general contractor type and operative
builders involved in the construction of buildings. The work performed may include
new work, additions, alterations, or maintenance and repairs. The on-site assembly of
precut, panelized, and prefabricated buildings and construction of temporary
buildings are included in this subsector. Part or all of the production work for which
the establishments in this subsector have responsibility may be subcontracted to other
construction establishmentsusually specialty trade contractors. Establishments in
this subsector are classified based on the types of buildings they construct. This
classification reflects variations in the requirements of the underlying production
processes.
Page 4-1
-------
Section 4: Industry Profile
Subsector 237 - Heavy and Civil Engineering Construction
This subsector comprises establishments whose primary activity is the construction of
entire engineering projects (e.g., highways and dams), and specialty trade contractors,
whose primary activity is the production of a specific component for such projects.
Specialty trade contractors in Heavy and Civil Engineering Construction generally are
performing activities that are specific to heavy and civil engineering construction
projects and are not normally performed on buildings. The work performed may
include new work, additions, alterations, or maintenance and repairs.
Specialty trade activities are classified in this subsector if the skills and equipment
present are specific to heavy or civil engineering construction projects. For example,
specialized equipment is needed to paint lines on highways. This equipment is not
normally used in building applications so the activity is classified in this subsector.
Traffic signal installation, while specific to highways, uses much of the same skills
and equipment that are needed for electrical work in building projects and is therefore
classified in Subsector 238, Specialty Trade Contractors. Establishments in this
subsector are classified based on the types of structures that they construct. This
classification reflects variations in the requirements of the underlying production
processes.
Subsector 238 - Special Trade Contractors
This subsector comprises establishments whose primary activity is performing
specific activities (e.g., pouring concrete, site preparation, plumbing, painting, and
electrical work) involved in building construction or other activities that are similar
for all types of construction, but that are not responsible for the entire project. The
work performed may include new work, additions, alterations, maintenance, and
repairs. The production work performed by establishments in this subsector is usually
subcontracted from establishments of the general contractor type or operative
builders, but especially in remodeling and repair construction, work also may be done
directly for the owner of the property. Specialty trade contractors usually perform
most of their work at the construction site, although they may have shops where they
perform prefabrication and other work. Establishments primarily engaged in
preparing sites for new construction are also included in this subsector. There are
substantial differences in types of equipment, work force skills, and other inputs
required by specialty trade contractors. Establishments in this subsector are classified
based on the underlying production function for the specialty trade in which they
specialize.
Table 4-1 provides a list of the 3-digit subsectors, 4-digit industry groups and 5-digitNAICS
industries in the construction sector.
Page 4-2
-------
Section 4: Industry Profile
Table 4-1. 2007 NAICS Subsectors, Industry Groups, and Industries Performing
Construction Activities that Might Disturb Land
2007 NAICS Sector 23 - Construction
236
2361
23611
236115
236116
236117
236118
2362
23621
236210
23622
236220
237
2371
23711
237110
23712
237120
23713
237130
2372
23721
237210
2373
23731
237310
2379
23799
237990
238
2381
23811
238110
23812
238120
23813
238130
23814
238140
23815
238150
Construction of Buildings
Residential Building Construction
Residential Building Construction
New Single-Family Housing Construction
New Multifamily Housing Construction
New Housing Operative Builders
Residential Remodelers
Nonresidential Building Construction
Industrial Building Construction
Industrial Building Construction
Commercial and Institutional Building Construction
Commercial and Institutional Building Construction
Heavy and Civil Engineering Construction
Utility System Construction
Water and Sewer Line and Related Structures Construction
Water and Sewer Line and Related Structures Construction
Oil and Gas Pipeline and Related Structures Construction
Oil and Gas Pipeline and Related Structures Construction
Power and Communication Line and Related Structures Construction
Power and Communication Line and Related Structures Construction
Land Subdivision
Land Subdivision
Land Subdivision
Highway, Street, and Bridge Construction
Highway, Street, and Bridge Construction
Highway, Street, and Bridge Construction
Other Heavy and Civil Engineering Construction
Other Heavy and Civil Engineering Construction
Other Heavy and Civil Engineering Construction
Specialty Trade Contractors
Foundation, Structure, and Building Exterior Contractors
Poured Concrete Foundation and Structure Contractors
Poured Concrete Foundation and Structure Contractors
Structural Steel and Precast Concrete Contractors
Structural Steel and Precast Concrete Contractors
Framing Contractors
Framing Contractors
Masonry Contractors
Masonry Contractors
Glass and Glazing Contractors
Glass and Glazing Contractors
Page 4-3
-------
Section 4: Industry Profile
2007 NAICS Sector 23 - Construction
23816
238160
23817
238170
23819
238190
2382
23821
238210
23822
238220
23829
238290
2383
23831
238310
23832
238320
23833
238330
23834
238340
23835
238350
23839
238390
2389
23891
238910
23899
238990
Roofing Contractors
Roofing Contractors
Siding Contractors
Siding Contractors
Other Foundation, Structure, and Building Exterior Contractors
Other Foundation, Structure, and Building Exterior Contractors
Building Equipment Contractors
Electrical Contractors and Other Wiring Installation Contractors
Electrical Contractors and Other Wiring Installation Contractors
Plumbing, Heating, and Air-Conditioning Contractors
Plumbing, Heating, and Air-Conditioning Contractors
Other Building Equipment Contractors
Other Building Equipment Contractors
Building Finishing Contractors
Drywall and Insulation Contractors
Drywall and Insulation Contractors
Painting and Wall Covering Contractors
Painting and Wall Covering Contractors
Flooring Contractors
Flooring Contractors
Tile and Terrazzo Contractors
Tile and Terrazzo Contractors
Finish Carpentry Contractors
Finish Carpentry Contractors
Other Building Finishing Contractors
Other Building Finishing Contractors
Other Specialty Trade Contractors
Site Preparation Contractors
Site Preparation Contractors
All Other Specialty Trade Contractors
All Other Specialty Trade Contractors
Source: U.S. Census Bureau 2008a
Before NAICS was created, C&D industries were classified using the SIC system. Any data
collected before January 1997 might still be classified under that system. SIC classifications are
relevant to the effluent guidelines, because certain U.S. Census Bureau data for the construction
industry were collected until 1994 and therefore classified under the SIC system rather than the
NAICS. Under the SIC system, industries that might perform land-disturbing activities were
classified under Division C-Construction, and Division H-Finance, Insurance, and Real Estate.
These divisions include the following SIC major groups (from U.S. Census Bureau 2008b):
SIC Major Group 15-Building Construction General Contractors and Operative
Builders
This group includes general contractors and operative builders primarily engaged in
the construction of residential, farm, commercial, or other buildings. General building
contractors who combine a special trade with their contracting are also included.
Page 4-4
-------
Section 4: Industry Profile
SIC Major Group 16-Heavy Construction Other Than Building Construction
Contractors
This group includes general contractors primarily engaged in heavy construction
other than building construction, such as highways and streets, bridges, sewers,
railroads, irrigation projects, flood control projects, and marine construction, as well
as special trade contractors primarily engaged in activities of a type clearly
specialized in such heavy construction and not normally performed on buildings or
building-related projects.
SIC Major Group 17-Construction Special Trade Contractors
This group includes special trade contractors who undertake activities of a type that
are specialized either in building construction or in both building and non-building
projects.
SIC Major Group 65-Real Estate
This group includes real estate operators and the owners and lessors of real property,
as well as buyers, sellers, developers, agents, and brokers.
Major groups 15 and 16 are further defined by the type of construction performed. Table 4-2
provides a list of the more specific industry groups and industries that might perform land-
disturbing activities.
The focus of the proposed rule is on construction activities carried out by firms covered by
NAICS codes 233 and 234 or SIC codes 15 and 16. (As discussed in Section V in the preamble
of the proposed rule, Special Trade Contractors, NAICS 238 or SIC 17, are typically
subcontractors and not identified as National Pollutant Discharge Elimination System (NPDES)
permittees.) Furthermore, the residential, nonresidential, and heavy construction subsectors
receive the greatest emphasis because they account for the vast majority of construction projects
and are responsible for most of the land disturbance in the United States.
Table 4-2. 1987 SIC Industry Groups Performing Construction Activities that Might
Disturb Land
SIC Major Group 15
Industry Group 152: General Building Contractors - Residential
1521
1522
General Contractors - Single-family Houses
General Contractors - Residential Buildings, Other Than Single-family
Industry Group 153: Operative Builders
1531
Operative Builders
Industry Group 154: General Building Contractors - Nonresidential
1541
1542
General Contractors - Industrial Buildings and Warehouses
General Contractors - Nonresidential Buildings, Other Than Industrial
Page 4-5
-------
Section 4: Industry Profile
SIC Major Group 16
Industry Group 161: Highway and Street Construction, Except Elevated Highways
1611
Highway and Street Construction, Except Elevated Highways
Industry Group 162: Heavy Construction, Except Highway and Street
1622
1623
1629
Bridge, Tunnel, and Elevated Highway Construction
Water, Sewer, Pipeline, and Communications and Power Line
Heavy Construction Not Elsewhere Classified
SIC Major Group 17
Industry Group 179: Miscellaneous Special Trade Contractors
1771
1794
Concrete Work
Excavation Work
SIC Major Group 65
Industry Group 655: Land Subdividers and Developers
6552
Land Subdividers and Developers, Except Cemeteries
Source: U.S. Census Bureau 2008b
4.2. INDUSTRY PRACTICES AND TRENDS
This section first provides a description of the types of C&D activities that result in the
disturbance of land and are responsible for the potential discharge of pollutants of concern to
surface waters. Then national estimates of the amount of disturbed acreage are provided.
Additional information including detailed descriptions of industry size and revenues is in the
document Economic Analysis for Proposed Effluent Guidelines and Standards for the
Construction and Development Category (EPA-821-R-08-008).
4.2.1. OVERVIEW OF CONSTRUCTION LAND-DISTURBING ACTIVITIES
Constructing a building or facility involves a variety of activities, including the use of equipment
that alters the site's environmental conditions. These changes include vegetation and top soil
removal, regrading, and drainage pattern alteration. The following provides a brief description of
typical land-disturbing activities at construction sites and the types of equipment employed.
4.2.1.1. Construction Site Preparation
Construction activities generally begin with the planning and engineering of the site and site
preparation. During this stage, mobile offices, which are usually housed in trailers, are
established on the construction site. The construction company uses these temporary structures to
handle vital activities such as preparing and submitting applicable permits, hiring employees and
subcontractors, and ensuring that proper environmental requirements are met. The entire
construction yard is delineated with erosion and sediment controls installed and security
measures established. The latter includes installing fences and signs to warn against trespassing
and to mark dangerous areas. After the site is secured, equipment is brought to the site (and is
stored there throughout the construction period).
Page 4-6
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Section 4: Industry Profile
4.2.1.2. Clearing, Excavating, and Grading
Construction on any size parcel of land almost always calls for a remodeling of the earth (Lynch
and Hack 1984). Therefore, actual site construction begins with site clearing and grading.
Organic materialin particular, rootscannot support the weight of buildings and must be
removed from the top layer of ground. (Some developers stockpile the organic material for use
during the landscaping phase of construction rather than paying for it to be hauled from the site.)
Construction contractors must ensure that earthwork activities meet local, state, and federal
regulations for soil and erosion control, runoff, and other environmental controls. The size of the
site, extent of water present, soil types, topography, and weather determine the kinds of
equipment used in site clearing and grading (Peurifoy and Oberlender 1989). Material that will
not be used on the site must be hauled away by tractor-pulled wagons, dump trucks, or
articulated trucks (Peurifoy and Oberlender 1989).
Equipment used for lifting excavated and cleared materials include aerial-work platforms,
forwarders, cranes, rough-terrain forklifts, and truck-mounted cranes. In addition, track loaders
are used for digging and dumping earth (Caterpillar 2000; Construction Equipment On-Line
2000; Lynch and Hack 1984; Peurifoy and Oberlender 1989).
Excavation and grading are performed by several different types of machines. These tasks can
also be done by hand, but this is generally more expensive (Lynch and Hack 1984). When
grading a site, builders typically ensure that new grades are as close to the original as possible, to
avoid erosion and storm water runoff (Lynch and Hack 1984). Proper grading also ensures a flat
surface for development and drains water away from constructed buildings.
Excavation and grading equipment includes backhoes, bulldozers (including the versatile tracked
bulldozer), loaders, directional drilling rigs, hydraulic excavators, motor graders, scrapers, skid-
steer loaders, soil stabilizers, tool carriers, trenchers, wheel loaders, and pipeliners. Equipment
selection depends on functions to be performed and specific site conditions (Caterpillar 2000;
Construction Equipment On-Line 2000; Lynch and Hack 1984; Peurifoy and Oberlender 1989).
Therefore, multiple types of equipment are used throughout the clearing and grading process.
Self-transporting trenching machines, wheel-type trenching machines, and ladder-type trenching
machines are also used during site excavation. Self-transporting trenching machines are used to
create shallow trenches, such as for underground wire and cables. This type of machine has a
bulldozer blade attached to the front, is highly maneuverable, and can be used to dig narrow,
shallow trenches. Wheel-type trenching machines also dig narrow trenches, most often for water
mains and gas and oil pipelines. Ladder-type trenching machines are used to dig deep trenches,
such as for sewer pipes. These machines might have a boom mounted at the rear. Along the
boom are cutter teeth and buckets that are attached to chains. As the machine moves, it digs dirt
and moves it to the sides of the newly formed trench (Peurifoy and Oberlender 1989).
Power shovels can also be used for excavating soils. They are used on all classes of earth that
have not been loosened. For solid rock, prior loosening is required. As materials are excavated,
they are immediately loaded onto trucks or tractor-pulled wagons and hauled from the site
(Peurifoy and Oberlender 1989). Hydraulic excavators, with either a front or a back shovel, are
also used to dig into the earth and to load a hauling vehicle. There are several categories of
Page 4-7
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Section 4: Industry Profile
hydraulic excavators, including backhoes, back shovels, hoes, and pull shovels. Hydraulic
excavators are one of the most widely used types of excavating equipment because of their ease
of use and their ability to remove the earth that caves as it is moved. They are effective
excavating machines, and they are easy to use in terms of loading some a hauling vehicle
(Peurifoy and Oberlender 1989).
Draglines, used to dig ditches or build levees, can transport soil within casting limits, thus
eliminating the need for hauling equipment (Peurifoy and Oberlender 1989). Draglines have a
bucket that hangs from a cable. The bucket is brought through the dirt and toward the operator
(Lynch and Hack 1984). Draglines can be used on both wet and dry ground and can dig earth out
of pits that contain water (Peurifoy and Oberlender 1989). They are most useful for making large
cuts and channels below the level of the machine as well as for making valleys, mounds, slopes,
and banks (Lynch and Hack 1984). Draglines have a lower output than power shovels and do not
excavate rock as well as power shovels (Peurifoy and Oberlender 1989).
Draglines can be converted to clamshells by replacing the dragline bucket with a clamshell
bucket. A clamshell is typically used for handling sand, gravel, crushed stone, sandy loam, and
other loose materials; it is not efficient in handling compacted earth, clay, or other dense
materials. A clamshell is lowered into a material, and the bucket closes on the material. It is then
raised over a hauling vehicle and the materials are deposited (Peurifoy and Oberlender 1989).
Scrapers, either self-powered or drawn by tractors, dig and compact materials by taking up earth
from its underside with toothed scoops and loading it into hauling vehicles. Scrapers are useful in
removing earth and weak or broken rock and for excavating hills and rock faces. Some scrapers
are designed for long hauls; others with good traction are used on steep slopes (Lynch and Hack
1984).
A crawler tractor, which pulls a rubber-tired self-loading scraper, is often used for short-haul
distances. The crawler tractor uses a drawbar pull to load the scraper. It has good traction and
can operate on muddy roads. It is, however, a slower vehicle and thus is more appropriate for
shorter hauls.
heel-type tractor-pulled scrapers, which come in two- and four-wheel drive tractors, are used for
longer hauling distances. Unlike the crawler tractor-pulled scrapers, the wheel-type tractor-pulled
scrapers do not maintain good traction. Under such conditions, a helper tractor, such as a
bulldozer, might be used (Peurifoy and Oberlender 1989).
All these machines shape and compact the earth, a crucial site preparation step. In addition,
earthwork activities might require that fill be brought in. In such cases, the fill must be spread in
uniform, thick layers and compacted to a specified density with an optimum moisture content.
Graders and bulldozers are the most common earth-spreading machines. Machines that compact
include tractor-pulled sheep's foot rollers, smooth-wheel rollers, pneumatic rollers, and vibrating
rollers, among other equipment (Peurifoy and Oberlender 1989). Rollers and scarifiers are used
either to compact or to break up the ground (Lynch and Hack 1984).
To remove rock, it must first be loosened and broken upusually through drilling or blasting.
Drilling equipment includes jackhammers, wagon drills, drifters, churn rills, and rotary drills;
Page 4-8
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Section 4: Industry Profile
each is designed to work on a specific size and type of rock. Dynamite and other explosives are
used to loosen rock (Peurifoy and Oberlender 1989).
After the materials have been excavated and removed and the ground cleared and graded, the site
is ready for construction.
4.2.2. CONSTRUCTION SITE SIZE CATEGORIES AND ESTIMATES OF AMOUNT
OF DISTURBED LAND
The regulatory options evaluated apply to construction sites of all types (i.e., residential,
commercial, and industrial). Because the costs for erosion and sediment control are largely
driven by site size, the U.S. Environmental Protection Agency (EPA) must estimate the
distribution of construction sites by size category, land use type, and geographic region to
estimate the total cost of the options. In addition, estimating distribution of sites by type allows
EPA to estimate the cost to each construction sector.
4.2.2.1. National Estimates of New Development
EPA used the National Land Cover Dataset (NLCD) to estimate the amount of new developed
land occurring annually in the conterminous United States (CONUS) between 1992 and 2001
(see Table 3-1 and Appendix E). EPA's comparison of the 1992 and 2001 NLCD resulted in an
estimated annual rate of development of approximately 590,000 acres per year. By overlaying
GIS layers of states and watersheds with the NLCD data, EPA was able to estimate the annual
number of acres of new development at both the state and watershed level (for state-level annual
estimates of new development, see Table 4-6). EPA used the Reach File Version 1.0 (RF1)
stream reach network and associated watershed boundaries for the watershed-level estimates.
EPA estimated annual development rates for approximately 44,000 RF1 watersheds where a net
increase in urban land cover was identified. Approximately 7,800 additional RF1 watersheds
showed either no change or a minor decrease in urban land uses between 1992 and 2001. RF1
watersheds and stream reaches are employed by the USGS SPARROW water quality model
the model EPA has selected to assess potential environmental benefits of additional regulation of
the industry (USGS 2008). The EVA Environmental Impact and Benefits Assessment for
Proposed Effluent Guidelines and Standards for the Construction and Development Category
(EPA-821-R-08-008) provides additional details and results of the water quality assessment
performed by EPA.
Because NLCD data does not exist for Alaska, Hawaii, and the U.S. territories, EPA's analysis
does not include cost, pollutant loading reduction, or environmental benefits estimates for these
areas. However, the amount of development in these areas is expected to be low compared to the
rest of the United States; therefore, any errors in EPA's estimates are expected to be minor.
EPA broadly characterized the acreage constructed annually into various future land uses and
construction project sizes. This characterization provides a basis for developing and then using
mathematical models that represent broad sectors of the industry to estimate compliance costs
and pollutant loading reductions. EPA divided NOIs into three groups according to site size:
small (< 10 acres), medium (10 to 30 acres), and large (> 30 acres) and three major land-use
Page 4-9
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Section 4: Industry Profile
types (residential, non-residential, and transportation). EPA determined the median project size
for each of these nine groupings.
Following are the nine construction site model projects that EPA used to represent the industry:
Large Residential - median size 33 acres
Large Nonresidential - median size 51 acres
Large Transportation - median size 79 acres
Medium Residential - median size 16.7 acres
Medium Non-Residential - median size 15 acres
Medium Transportation - median size 16 acres
Small Residential - median size 3 acres
Small Nonresidential - median size 2.6 acres
Small Transportation - median size 3 acres
These model projects were identified after reviewing more than 30,000 Notices of Intent (NOIs)
submitted by permittees in 38 states (see Appendix C, Analysis of Construction Industry Trends
using Notice of Intent Records). The NOI records, which serve as the basis for EPA's sector
analysis were individually characterized on the basis of land use, and each of the NOI records
used provided site construction acreage information.
Individually, the site project models each represent large fractions of the construction projects
developed annually, and cover the major project types in the C&D industry. Table 4-3
summarizes the breakdown by number and percentage of reviewed NOI permits represented by
each sector model, and the quantity and percent of constructed acreage represented by each
sector model.
Table 4-3. Summary of NOI Data
Small Transportation Projects
Small Residential Projects
Small Nonresidential Projects
Medium Transportation Projects
Medium Residential Projects
Medium Nonresidential Projects
Large Transportation Projects
Large Residential Projects
Large Nonresidential Projects
TOTALS
Number of
NOIs
1,261
8,322
12,915
395
4,236
3,232
407
2,130
1,353
34,251
Percent of
NOIs
3.7%
24.3%
37.7%
1.2%
12.4%
9.4%
1.2%
6.2%
4.0%
Acres in each
NOI category
4,496
32,139
43,141
6,884
74,322
54,182
44,060
178,803
149,931
587,958
Percent of total
NOI acres
0.8%
5.5%
7.3%
1.2%
12.6%
9.2%
7.5%
30.4%
25.5%
Page 4-10
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Section 4: Industry Profile
As detailed in section 3.5.3, EPA has elected to use 11 indicator cities as a means to estimate
construction site erosion rates and removals due to regulatory options. EPA used the nine model
projects along with state-specific data on rainfall quantities and development rates to estimate
costs of regulatory options.
EPA found that a small percentage of the total site acreage, according to the NOT data reviewed,
was from other land use subcategories, including railroads, mines, water projects, parks, airports,
and farms. Collectively, these six subcategories contain about 10 percent of the total site acreage
found within the pool of NOT records. EPA did not elect to develop model projects for these
additional project types. Because EPA's analysis considered all the approximately 590,000 acres
estimated to be developed annually, EPA assumes that the influence of these six subcategories is
captured in the analysis of the other, more common, land use types.
4.2.2.2. Distribution of Developed Acreage by Project Size
EPA's assessment of NOT records provides a basis for estimating a construction site size
distribution. As detailed in Appendix C, Analysis of Construction Industry Trends using Notice
of Intent Records, EPA evaluated a pool of NOI records for which site size information is
available. In its analysis, EPA used only NOI records that EPA was able to characterize as being
either residential, nonresidential, or transportation related. Table 4-4 summarizes the results of
EPA's NOI analysis.
Table 4-4. NOI Derived Construction Site Size Distribution
Site size (acres)
Percent of Site Acreage Above
0
100.0
5
93.6
10
86.4
15
79.9
20
73.8
25
68.7
30
64.2
35
60.6
40
57.6
Information in Table 4-4 provides a basis for EPA's consideration of options that include
specific site size cutoffs. For example, if an option were to apply only to sites of 10 or more
acres, 86.4 percent of construction site acreage will be affected under the option requirements.
4.2.2.3. Distribution of Developed Acreage by Climate
As a part of its analysis, EPA evaluated the average annual rainfall depths across the contiguous
states using the 1-km resolution United States Average Monthly or Annual Precipitation (1971-
2000) PRISM Group raster data coverage (PRISM Group 2006). Generally, the larger the annual
rainfall, the larger the construction site runoff volume and annual soil erosion will be. In
addition, construction sites with high annual rainfall amounts also generally have larger amounts
of runoff. This tends to increase the size of any controls designed to treat construction site runoff.
Some of the regulatory options EPA considered incorporated an annual precipitation cutoff, such
that only construction sites in areas with annual precipitation amounts above a threshold would
be required to meet specific regulatory requirements. By overlaying the PRISM data coverage
with the RF1-level estimates of annual development, EPA was able to estimate the percent and
quantity of annual construction that would be affected given various annual precipitation cutoffs
(see Tables 3-4 and 3-5).
Page 4-11
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Section 4: Industry Profile
4.2.2.4. State-Level Estimation of Developed Acreage and Sites
Table 3-1 indicates the per-state estimated total number of acres developed on the basis of EPA's
assessment of land cover changes between 1992 and 2001. To estimate the number of model
projects within each state, EPA first applied the distribution of the percent of acres by model
projects by category contained in Table 4-3 to each state's estimate of annual developed acres.
Then, EPA divided the acres in each category by the median model project size and rounded
results to whole numbers to estimate the number of model projects in each category. These
results are shown in Table 4-5.
Table 4-6 indicates the total annually constructed acreage represented by the nine model projects
and the acreage allocated to each state. Rounding the number of model projects to whole
numbers results in a slight difference between the total national modeled acreage and the
estimated total acreage produced by comparing NLCD data sets. As shown in Table 3-1, the
NLCD comparison identified an annual development rate of 589,911 acres. The construction site
model projects presented in Table 4-6 represents a total acreage of 589,916 acres.
The number of construction site model projects assigned to each state provides the basis for
EPA's analysis of pollutant loading reductions and compliance cost estimates for the regulatory
options.
4.2.2.5. Soil Texture Analysis
EPA evaluated options that incorporate applicability criteria tied to soil clay content. Clay
particles in the proposal are defined as those particles that are smaller than 2 microns in
diameter. To determine acres in-scope given various percent clay contents, EPA evaluated a
national soils data layer (see section 3.5.4) in combination with RF1-level estimates of the
amount of construction activity occurring annually. Table 4-7 indicates the annual quantity of
developed acres that would be in-scope for various clay contents. Table 4-8 indicates total state
acreage in-scope for various clay contents. The state and national totals in Table 4-7 do not
exactly match the totals contained in Tables 3-1 and 4-6 because of incomplete GIS coverage,
but the difference is minor (less than 1 percent).
4.2.2.6. Rainfall and Runoff Factor Analysis
EPA evaluated options that incorporate applicability provisions that are tied to the rainfall and
runoff factor (or R-factor) contained in the Revised Universal Soil Loss Equation (RUSLE) (see
section 3.5.6). To evaluate the influence of setting applicability criteria at various annual R-
factor thresholds and to estimate the acres of new construction that would be in-scope given
various annual R-factor thresholds, EPA overlaid GIS layers of annual R-factors with the RF1-
level estimates of annual developed acres from the NLCD analysis. Tables 3-6 and 3-7
summarize developed acres that would be in-scope in each state given annual R-factor values
from 10 to 100. Figure 3-15 shows annual R-factor values for the CONUS.
Page 4-12
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Table 4-5. Estimated Number of Model Construction Projects Developed Annually
as
era
re
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
Residential
Small
265
249
155
500
289
18
15
694
595
~
103
374
226
184
411
182
234
82
119
60
410
170
216
247
118
111
149
Medium
110
103
64
208
120
8
6
288
247
~
43
155
94
76
171
76
97
34
49
25
170
71
90
103
49
46
62
Large
134
126
78
253
146
9
8
351
300
~
52
189
114
93
208
92
118
41
60
31
207
86
109
125
59
56
75
Nonresidential
Small
409
385
240
774
447
28
23
1,074
920
~
160
578
349
285
636
282
362
127
185
94
635
263
335
382
182
172
230
Medium
89
84
52
168
97
6
5
234
200
~
35
126
76
62
138
61
79
28
40
20
138
57
73
83
40
37
50
Large
73
68
42
137
79
5
4
190
163
~
28
103
62
50
113
50
64
22
33
17
112
47
59
68
32
30
41
Transportation
Small
37
35
22
70
40
3
2
97
83
~
14
52
32
26
57
25
33
11
17
8
57
24
30
35
16
15
21
Medium
11
10
6
20
12
1
1
28
24
~
4
15
9
7
16
7
9
3
5
2
16
7
9
10
5
4
6
Large
14
13
8
26
15
1
1
36
31
~
5
19
12
10
21
9
12
4
6
3
21
9
11
13
6
6
8
Totals
1,142
1,073
667
2,156
1,245
79
65
2,992
2,563
~
444
1,611
974
793
1,771
784
1,008
352
514
260
1,766
734
932
1,066
507
477
642
-------
as
era
re
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Nation
Residential
Small
33
78
85
141
342
119
317
305
133
292
7
295
151
239
1,118
153
10
276
233
64
138
52
1
10,758
Medium
14
32
35
58
142
49
132
127
55
121
3
122
63
99
464
63
4
115
97
27
57
21
-
4,465
Large
16
39
43
71
173
60
160
154
67
147
3
149
77
121
565
77
5
140
118
32
70
26
1
5,434
Nonresidential
Small
50
120
132
218
529
185
491
472
206
452
11
456
235
369
1,730
237
16
427
361
99
213
80
2
16,648
Medium
11
26
29
47
115
40
107
103
45
98
2
99
51
80
377
52
3
93
79
22
46
17
-
3,620
Large
9
21
23
39
94
33
87
84
36
80
2
81
42
65
307
42
3
76
64
18
38
14
-
2,950
Transportation
Small
5
11
12
20
48
17
44
43
19
41
1
41
21
33
156
21
1
39
33
9
19
7
-
1,503
Medium
1
3
3
6
14
5
13
12
5
12
-
12
6
10
45
6
-
11
9
3
6
2
-
431
Large
2
4
4
7
18
6
17
16
7
15
-
15
8
12
58
8
1
14
12
3
7
3
-
557
Totals
141
334
366
607
1,475
514
1,368
1,316
573
1,258
29
1,270
654
1,028
4,820
659
43
1,191
1,006
277
594
222
4
46,366
-------
Table 4-6. Estimated Annually Developed Acreage Represented by Model Construction Projects
as
era
re
in
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
Residential
Small
793
745
464
1,499
865
55
46
2,081
1,782
0
310
1,121
676
552
1,232
545
702
246
357
181
1,230
510
648
741
353
332
446
Medium
1,833
1,723
1,073
3,466
2,001
127
105
4,812
4,120
0
717
2,592
1,564
1,276
2,849
1,261
1,623
568
826
420
2,844
1,180
1,499
1,713
816
768
1,031
Large
4,410
4,144
2,581
8,339
4,814
306
253
11,576
9,911
0
1,726
6,235
3,763
3,070
6,854
3,034
3,906
1,367
1,987
1,010
6,841
2,838
3,606
4,121
1,963
1,848
2,480
Nonresidential
Small
1,064
1,000
623
2,012
1,162
74
61
2,793
2,391
0
416
1,504
908
741
1,654
732
942
330
480
244
1,651
685
870
994
474
446
598
Medium
1,336
1,256
782
2,527
1,459
93
77
3,508
3,003
0
523
1,889
1,140
930
2,077
919
1,184
414
602
306
2,073
860
1,093
1,249
595
560
752
Large
3,698
3,475
2,164
6,993
4,037
257
213
9,707
8,311
0
1,447
5,228
3,155
2,574
5,747
2,544
3,275
1,146
1,667
847
5,736
2,379
3,023
3,455
1,646
1,550
2,080
Transportation
Small
111
104
65
210
121
8
6
291
249
0
43
157
95
77
172
76
98
34
50
25
172
71
91
104
49
46
62
Medium
170
160
99
321
185
12
10
446
382
0
66
240
145
118
264
117
150
53
77
39
263
109
139
159
76
71
95
Large
1,087
1,021
636
2,055
1,186
75
62
2,852
2,442
0
425
1,536
927
756
1,689
748
962
337
490
249
1,686
699
888
1,015
484
455
611
Totals
14,502
13,628
8,487
27,422
15,830
1,007
833
38,066
32,591
0
5,673
20,502
12,373
10,094
22,538
9,976
12,842
4,495
6,536
3,321
22,496
9,331
11,857
13,551
6,456
6,076
8,155
-------
as
era
re
O\
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
Nation
Residential
98
233
255
422
1,024
357
951
915
398
875
21
884
454
715
3,351
459
31
828
699
192
414
155
0
4
32,247
226
540
590
976
2,369
826
2,199
2,115
921
2,023
48
2,044
1,050
1,654
7,749
1,060
72
1,915
1,617
444
957
359
0
8
74,569
543
1,298
1,420
2,348
5,698
1,988
5,291
5,088
2,215
4,867
115
4,917
2,527
3,980
18,643
2,551
173
4,606
3,890
1,068
2,302
865
0
20
179,396
Nonresidential
131
313
343
567
1,375
480
1,277
1,228
535
1,174
28
1,186
610
960
4,498
616
42
1,111
939
258
555
209
0
5
43,289
165
393
430
712
1,727
602
1,603
1,542
671
1,475
35
1,490
766
1,206
5,649
773
52
1,396
1,179
324
697
262
0
6
54,362
455
1,089
1,191
1,969
4,778
1,667
4,437
4,266
1,858
4,081
96
4,123
2,119
3,338
15,633
2,139
145
3,862
3,262
896
1,930
725
0
17
150,430
Transportation
14
33
36
59
143
50
133
128
56
122
3
124
64
100
469
64
4
116
98
27
58
22
0
1
4,511
21
50
55
90
219
77
204
196
85
187
4
189
97
153
718
98
7
177
150
41
89
33
0
1
6,907
134
320
350
579
1,404
490
1,304
1,254
546
1,199
28
1,212
623
981
4,594
629
43
1,135
959
263
567
213
0
5
44,205
1,787
4,269
4,670
7,722
18,737
6,537
17,399
16,732
7,285
16,003
378
16,169
8,310
13,087
61,304
8,389
569
15,146
12,793
3,513
7,569
2,843
0
67
589,916
-------
Section 4: Industry Profile
4.2.2.7. Estimates of Number of Sites and Acreage Covered by Regulatory Options
EPA evaluated several regulatory options that included combinations of site size, R-factor and
percent clay content. To estimate acres affected by various combinations of R-factors and clay
contents, EPA combined the national clay data layer along with the R-factor data layer and RF1-
level estimates of amount of development using GIS. Using the distribution of construction sites
by size, EPA was able to estimate the acres that would be subject to various components of the
proposed regulation. EPA estimates that under Option 1, approximately 120,700 acres per year,
or approximately 20 percent of annual constructed acres, would be required to install larger
sediment basins. Under Option 2, approximately 234,000 acres per year, or approximately 40
percent of annual construction acreage, would be required to meet the turbidity standard. In
addition, approximately 64,000 acres, or 11 percent of annual construction acreage, would be
required to install larger sediment basins under Option 2. Under Option 3, approximately
509,000 acres, or 86 percent of annual construction acreage, would be required to meet a
turbidity limit. Under all three options, all areas of the country would be required to meet the
best management practice requirements contained in the proposed rule. Table 4-9 summarizes
the acres subject to the proposed option. Figure 4-1 generally shows areas of the country that
would be required to meet the turbidity limit under Option 2. In this figure, areas in white are in
areas with an annual R-factor of less than 50 or with less than 10 percent by mass of clay
particles in the surface soil layer, while those areas in blue are in areas with an annual R-factor of
50 or greater and with 10 percent or more by mass of clay particles in the surface soil layer.
Therefore, only areas in the blue-colored area would be considered in-scope for the turbidity
limit.
Under Option 2, EPA would allow use of average annual precipitation of 20 or more inches
instead of an R-factor of 50 or more as an applicability provision for the turbidity limit for areas
of the country, such as Alaska, Hawaii and the U.S territories, where annual R-factor maps are
not readily available or permittees have not calculated R-factors from available precipitation
data. Figure 4-2 shows mean annual precipitation for Alaska for the period 1961 to 1990
(Western Regional Climate Center 2008) and Figure 4-3 shows mean annual precipitation for
Hawaii for the period 1971-2000 (PRISM Group 2006). These figures provide an illustration of
the areas of Alaska and Hawaii that would likely be subject to the turbidity standard. EPA
expects that permitting authorities would develop detailed applicability information to address
these cases.
Page 4-17
-------
s*
era
oo
Clay>=10%&
R factor >= 50
Figure 4-1. Areas of the CONUS Required to Meet Turbidity Limit.
.
§
-------
Mean Annual Precipitation, Alaska - Yukon
era
re
4-
601-800
801-1000
1001-1500
1501-2000
2001 -SOOO
3001 -6000
5001 -7000
7001 - 1 SOOO
No Data
Precipitation (mm)
0-200
201-250
251-SOO
S01-350
351-400
401-450
451-500
501-600
Spatial Climate Analysis Service
Feb.2000
Figure 4-2. Alaska's Mean Annual Precipitation 1961 to 1990.
-------
Section 4: Industry Profile
Mean Annual Precipitation
Inches
10-20
20-30
30-40
40-50
50-60
60-70
70-80
80-90
90-100
100-110
110-120
120 - 130
HI 130-140
I 140-150
150-160
^H 130-170
| |170-180
(ZZl 180-190
| |190-200
IZZl 200-210
BH 210 - 220
HH 220 - 230
^H 230 - 250
i | 250-270
270 - 300
300 - 330
Figure 4-3. Hawaii's Mean Annual Precipitation 1971 to 2000.
Page 4-20
-------
Table 4-7. Annual State Developed Acres in Various Percent Clay Fractions
era
re
Percent clay =»
Alabama
Arkansas
Arizona
California
Colorado
Connecticut
Delaware
Florida
Georgia
Iowa
Idaho
Illinois
Indiana
Kansas
Kentucky
Louisiana
Massachusetts
Maryland
Maine
Michigan
Minnesota
Missouri
Mississippi
Montana
North Carolina
North Dakota
Nebraska
New Hampshire
New Jersey
New Mexico
Nevada
0-5
71
0
2
926
5
30
12
32,536
3,217
1
12
19
1
2
2
472
131
257
26
6,692
588
100
1
5
857
0
383
3
437
30
10
5-10
3,755
100
255
4,722
785
563
665
5,472
7,857
2
298
44
1,286
1,729
46
1,962
2,892
788
1,443
8,836
2,557
86
1,112
65
3,430
76
1,669
1,425
1,894
1,266
509
10-15
6,822
6,581
2,911
7,077
3,125
440
274
270
5,956
944
4,466
2,425
2,123
5,496
5,186
6,195
225
4,007
3,124
4,405
2,744
7,069
8,840
706
8,264
785
1,610
379
1,776
1,750
6,576
15-20
2,905
736
7,657
5,413
6,652
0
~
75
15,402
1,301
847
15,344
8,519
4,126
2,822
1,599
102
1,519
167
2,474
1,896
2,908
802
2,428
6,468
5,136
609
~
162
1,433
887
20-25
600
418
2,737
4,434
3,556
~
~
~
292
4,990
63
2,478
426
6,002
757
882
~
7
~
76
859
3,060
344
1,425
~
466
227
~
~
144
66
25-30
129
254
110
1,989
1,108
~
~
~
11
2,275
7
183
5
2,543
841
752
~
~
~
352
528
288
238
857
~
34
1,232
~
~
69
120
>30
233
412
16
3,324
756
~
~
1
9
607
0
55
120
2,706
349
1,228
~
~
~
128
230
41
552
1,105
~
137
435
~
~
16
~
State total
14,515
8,500
13,688
27,884
15,988
1,033
951
38,355
32,744
10,122
5,692
20,548
12,480
22,605
10,002
13,089
3,350
6,578
4,760
22,963
9,402
13,550
11,891
6,592
19,019
6,634
6,166
1,807
4,270
4,709
8,168
-------
era
re
Percent clay =»
New York
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Virginia
Vermont
Washington
Wisconsin
West Virginia
Wyoming
Total
% in Fraction
Cumulative % in Fraction
0-5
229
24
28
144
29
1
2,859
1
0
553
16
267
1
65
413
4
2
51,465
9%
9%
5-10
1,566
241
982
1,232
55
212
8,054
111
87
6,130
518
1,513
18
2,471
2,571
35
126
83,510
14%
23%
10-15
5,233
9,256
8,455
2,359
14,432
147
4,846
870
7,392
11,371
977
8,869
500
8,307
2,804
2,126
1,065
201,562
34%
57%
15-20
599
5,831
4,168
2,224
1,662
~
690
3,180
4,799
6,815
6,381
3,575
26
1,714
1,419
852
912
145,239
24%
81%
20-25
129
1,685
1,571
611
6
~
18
1,988
731
5,140
431
564
11
249
319
342
622
48,726
8%
89%
25-30
39
68
1,200
603
~
~
5
1,014
104
5,511
87
292
11
3
9
63
122
23,055
4%
93%
>30
72
364
351
157
~
~
~
1,169
5
26,495
1
85
12
2
73
97
16
41,358
7%
100%
State total
7,868
17,467
16,756
7,331
16,184
360
16,471
8,332
13,119
62,016
8,411
15,165
578
12,810
7,608
3,519
2,865
594,916
-------
Table 4-8. State Total Acres in Various Percent Clay Fractions
Percent clay =»
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Montana
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
0-5
44,937
885,828
1,830
3,505,825
42,749
74,760
26,313
29,124,995
2,958,921
751,490
61,620
24,463
5,668
452
5,785
2,015,854
131,101
243,055
250,591
9,249,589
3,003,300
16,722
142,808
189,402
10,746,079
92,851
11,454
763,239
599,173
782,650
1,680,960
5-10
8,612,982
6,781,085
403,679
22,822,008
3,606,090
2,171,833
1,069,896
6,042,465
17,289,276
3,141,449
269,530
1,359,624
7,088
1,878,414
298,726
3,725,177
5,853,138
896,490
3,375,615
13,508,820
13,953,272
1,756,196
144,416
1,052,152
10,046,830
2,751,452
3,646,834
1,846,632
5,675,590
5,977,736
10,585,082
10-15
14,810,271
20,614,063
22,983,199
25,404,458
20,549,986
985,313
389,888
509,706
6,560,210
19,795,382
9,029,876
8,403,777
3,527,356
18,649,413
16,345,138
10,956,136
11,127,920
3,588,173
620,678
10,529,585
11,887,104
19,112,105
21,433,697
7,658,539
13,436,477
29,807,706
2,228,159
1,832,592
27,465,625
21,932,781
12,503,521
15-20
6,529,033
22,498,143
3,844,556
20,513,830
25,296,937
3,280
0
89,408
10,407,774
9,657,471
21,141,590
11,818,540
5,280,593
12,485,930
5,230,883
3,204,582
657,736
1,515,076
899,897
3,802,660
6,077,935
2,450,885
10,447,732
21,751,812
5,738,791
21,299,211
0
396,973
26,636,781
1,826,277
7,162,561
20-25
1,319,622
7,030,190
1,786,895
12,023,014
7,898,678
0
0
0
481,850
715,242
4,453,414
1,533,023
14,788,510
8,582,328
1,598,583
2,285,703
0
11,715
0
369,817
7,697,705
1,504,726
8,850,695
15,766,710
2,831,434
575,110
0
0
5,013,372
434,682
0
25-30
599,129
2,566,592
1,334,068
4,655,984
1,476,849
0
0
0
16,073
229,160
1,024,672
20,757
8,361,470
5,521,984
1,109,831
1,714,877
0
0
0
241,167
8,495,431
1,185,805
3,234,132
9,132,519
2,662,836
1,029,917
0
0
977,014
92,257
0
>30
1,119,922
915,525
3,736,017
5,754,918
481,462
0
0
1,070
17,562
247
443,025
136,634
4,141,341
5,613,986
1,338,907
5,520,495
0
0
0
106,602
2,135,487
4,651,669
545,735
13,649,439
3,213,610
0
0
0
172,628
201,067
0
State total
33,035,896
61,291,426
34,090,245
94,680,037
59,352,750
3,235,185
1,486,097
35,767,644
37,731,666
34,290,441
36,423,727
23,296,817
36,112,024
52,732,506
25,927,854
29,422,824
17,769,896
6,254,510
5,146,781
37,808,240
53,250,235
30,678,107
44,799,216
69,200,572
48,676,057
55,556,248
5,886,447
4,839,437
66,540,183
31,247,451
31,932,125
-------
era
re
Percent clay =»
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Dakota
South Carolina
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
National Total
% in Fraction
Cumulative % in Fraction
0-5
9,884
56,072
153,668
1,000,415
49,553
8,896
66,163
2,359,317
5,436
4,112,583
1,669,341
28,177
309,737
133,870
4,632
1,563,705
216,567
79,182,479
4%
4%
5-10
460,300
77,429
3,075,911
3,374,635
127,959
481,255
1,120,777
8,242,264
225,022
13,675,458
3,497,268
88,705
2,849,990
4,848,745
59,519
10,757,100
1,843,581
215,355,492
12%
17%
10-15
4,893,923
10,126,108
21,586,652
13,164,763
21,815,603
165,637
4,613,557
7,844,711
16,800,299
24,105,815
10,975,155
5,364,034
14,290,883
28,176,918
9,098,514
20,200,136
18,811,672
626,713,220
35%
52%
15-20
31,733,223
9,627,074
11,715,655
19,536,164
7,164,585
0
14,995,151
1,272,505
8,221,207
26,935,881
31,000,753
225,983
7,107,094
5,946,099
3,819,661
2,879,574
11,951,494
462,798,983
26%
78%
20-25
4,732,932
4,177,715
4,671,183
5,076,785
41,514
0
8,102,514
42,255
1,336,166
22,802,414
1,224,730
51,958
635,585
658,862
1,858,659
509,664
7,249,557
170,725,511
10%
88%
25-30
944,669
640,084
2,698,674
2,887,108
0
0
5,118,772
7,997
359,117
19,726,369
179,410
139,816
220,665
3,244
134,493
96,522
1,481,565
90,321,028
5%
93%
>30
1,298,372
2,103,301
889,610
613,757
0
0
12,966,793
0
154,223
54,209,368
17,068
213,365
61,282
20,016
552,333
174,993
856,661
128,028,486
7%
100%
State total
44,073,304
26,807,782
44,791,352
45,653,628
29,199,215
655,788
46,983,728
19,769,048
27,101,470
165,567,887
48,563,724
6,112,037
25,475,236
39,787,754
15,527,811
36,181,693
42,411,096
1,773,125,199
-------
Table 4-9. Acres Subject to Proposed Regulation
era
re
in
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Option 1
Option 2
Turbidity
limit
Basins
Option 3
No Data
12,598
~
~
13,682
~
~
~
28,168
6,726
898
5,314
2,557
1,809
234
117
201
13,653
5,872
~
~
11,873
~
~
~
14,515
12,598
11,792
7,292
23,701
13,682
871
738
32,881
28,168
No Data
~
~
10,725
~
~
~
~
~
~
~
~
~
~
~
5,551
~
12,905
7,039
6,408
13,218
6,296
6,609
2,010
3,455
201
4,599
3,935
6,810
8,502
~
~
~
3,686
~
~
~
~
~
~
~
~
~
~
~
5,551
4,846
17,708
10,725
8,719
19,482
8,592
11,054
3,826
5,635
2,876
19,365
8,098
10,216
11,744
5,551
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Totals
Option 1
5,239
~
~
3,646
~
~
16,244
~
15,076
~
~
~
281
~
~
~
~
~
509
~
~
~
6,538
2,446
~
120,701
Option 2
Turbidity
limit
-
~
201
1,262
84
3,818
9,250
2,791
10,862
9,998
~
10,115
84
3,422
4,800
8,222
34,111
~
397
8,502
2,791
2,160
2,875
~
~
233,836
Basins
-
~
~
2,384
~
~
6,994
~
4,213
~
~
~
197
~
~
~
~
~
112
~
~
~
3,664
2,446
~
64,305
Option 3
5,239
7,079
1,560
3,646
3,975
6,654
16,244
5,635
15,076
14,486
6,273
13,797
281
13,946
7,227
11,268
53,002
7,242
509
13,092
11,054
3,040
6,538
2,446
33
509,497
-------
Section 4: Industry Profile
4.3. REFERENCES
Caterpillar. 2000. Caterpillar, Inc., Peoria, IL. .
Construction Equipment On-line. 2000. Reed Business Information, Oak Brook, IL,
Peurifoy, Robert L., and Garold D. Oberlender. 1989. Estimating Construction Costs. 4th ed.
McGraw Hill Book Company, New York.
PRISM Group. 2006. United States Average Monthly or Annual Precipitation (1971-2000).
Oregon State University, . Accessed March 2008.
PRISM Group. 2006. Mean Annual Precipitation for Hawaii (1971-2000). Oregon State
University.
. Accessed November 6, 2008.
U.S. Census Bureau. 2008a. North American Industry Classification System (NAICS) 2007. U.S.
Department of Commerce, U.S. Census Bureau, Washington, DC.
. Updated March 28, 2008; accessed April
15,2008.
U.S. Census Bureau. 2008b. North American Industry Classification System (NAICS) 2007. U.S.
Department of Commerce, U.S. Census Bureau, Washington, DC.
. Accessed
November 7, 2008.
USGS (U.S. Geological Survey). 2008. The SPARROW Surface Water-Quality Model: Theory,
Application and User Documentation. U.S. Geological Survey Techniques and Methods,
Book 6, Section B, Chapter 3. U.S. Geological Survey, Reston, VA.
Western Regional Climate Center. 2008. Mean Annual Precipitation, Alaska-Yukon. Spatial
Climate Analysis Service . Accessed November 6,
2008.
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Section 5: Selection of Pollutants for Regulation
5. SELECTION OF POLLUTANTS FOR REGULATION
5.1. INTRODUCTION
Construction and development (C&D) activities can generate a broad range of environmental
impacts by introducing new sources of contamination and by altering the physical characteristics
of the affected land area. In particular, these activities can result in both short- and long-term
adverse impacts on surface water quality in streams, rivers, and lakes in the affected watershed
by increasing the loads of various pollutants in receiving waterbodies, including sediments,
metals, organic compounds, pathogens, and nutrients. Ground water also can be adversely
affected through diminished recharge capacity. Other potential impacts include the physical
alteration of existing streams and rivers due to the excessive flow and velocity of stormwater
runoff.
Construction activities typically involve excavating and clearing existing vegetation. During the
construction period, the affected land is usually stripped and the soil compacted, leading to the
potential for increased stormwater runoff and high rates of erosion. If the denuded and exposed
areas contain hazardous contaminants or pollutants (either naturally occurring or from previous
land uses) they can be carried at increased rates to surrounding waterbodies by stormwater
runoff. Although the denuded construction site is only a temporary state (usually lasting less than
6 months), the landscape is permanently altered even after the land has been restored by
replanting vegetation.
Pollutants associated with C&D stormwater discharges can adversely affect the environment in a
number of ways. Potential effects include impairment of water quality, destruction of aquatic life
habitats, and enlargement of floodplains. The Environmental Impact andBenefits Assessment for
Proposed Effluent Guidelines and Standards for the Construction and Development Category
(EPA-821-R-08-009) discusses the potential affects of C&D stormwater runoff on the
environment. The discussion in the remainder of this section focuses on those pollutants
generated at a site during active construction.
5.2. POLLUTANTS ASSOCIATED WITH CONSTRUCTION AND LAND
DEVELOPMENT STORMWATER RUNOFF
There are a number of pollutants associated with C&D stormwater runoff. The description of
pollutants in this subsection does not represent the complete suite of contaminants that can be
found in the runoff, but focuses instead on those that are known to be the most prevalent and of
greatest concern to the environment. These pollutants include sediment, metals, polycyclic
aromatic hydrocarbons (PAHs), oil and grease, and pathogens.
5.2.1. SEDIMENT
Sediment is an important and ubiquitous constituent in urban stormwater runoff. Surface runoff
and raindrops detach soil from the land surface, resulting in sediment transport into streams and
rivers. Sediment and turbidity can affect habitat, water quality, temperature, pollutant transport,
and can cause sedimentation in downstream receiving waters. The effects of excess sediment in
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Section 5: Selection of Pollutants for Regulation
the water include direct physical effects such as reducing visibility and light in the water column,
physical abrasion of plant surfaces, clogging gill openings, and entombing of eggs and fry in
redds. Effects can also be indirect, as in changes to the chemical composition (e.g., pH, hardness)
of the water, light penetration or turbidity, and/or temperature profile, which in turn affect
primary productivity with repercussions in terms offish behavior, and overall community
profiles and trophic structure.
Sediment level measurement can be divided into several distinct subgroups:
Total suspended solids (TSS) are a dry weight measure of the suspended particulate
material in water. The measurement of TSS in urban stormwater allows for estimation
of sediment transport, which can have significant effects locally and in downstream
receiving waters. TSS is typically measured in milligrams per liter (mg/L).
Turbidity is a function of the suspended solids and is a measure of the ability of light
to penetrate the water. Turbidity readings are somewhat dependent on particle size,
shape, and color. Turbidity is typically measured in Nephelometric Turbidity Units
(NTUs). Turbidity can exhibit control over biological functions, such as the ability of
submerged aquatic vegetation to receive light.
Total dissolved solids are a measure of the dissolved constituents in water and are a
primary indication of the purity of drinking water.
Settleable solids, expressed as milliliters per liter (mL/L), are a measure of the solids
that will settle to the bottom of a cone-shaped container (called an Imhoff cone) in a
60-minute period. Settleable solids are primarily a measure of particles that can be
removed by sedimentation.
Suspended Sediment Concentration (SSC) is a measure similar to TSS; however,
there are differences in the two analytical methods. SSC is determined by measuring
the dry weight of all sediment from a known volume of sample. TSS is measured by
filtering a subsample and measuring the weight of the dried solids. SSC and TSS
values from the same sample can vary greatly, especially as the fraction of sand-sized
particles in a sample increases. This is due primarily to the subsampling procedure
involved in TSS calculations where typically a pipette is used to withdraw a
subsample from the sample container. This procedure might not capture a
representative fraction of larger particles in the subsample. The U.S. Geological
Survey (USGS) has analyzed differences attributable to the two methods and
determined that SSC is a more appropriate measure of the mass of solids in natural-
water samples (Gray et al. 2000). This may also apply to stormwater discharges,
especially if a significant fraction of sand-sized particles are present.
Erosion from construction sites can be a significant source of sediment pollution to nearby
streams. A number of studies have shown high concentrations of TSS in uncontrolled runoff
from construction sites, and results from these studies are summarized in Table 5-1. One study,
conducted in 1986, calculated that construction sites are responsible for an estimated export of
80 million tons of sediment into receiving waters each year (Goldman et al. 1986). On a unit area
basis, construction sites can export sediment at 20 to 1,000 times the rate of other land uses
(Schueler 1997).
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Section 5: Selection of Pollutants for Regulation
Table 5-1. Studies of Uncontrolled Soil Erosion as TSS from Construction Sites
Site
Seattle, Washington
SR204
Mercer Island
RT1
RT2
SB1
SB2
SB4
Pennsylvania Test Basin
Georgia Model
Maryland Model
Uncontrolled Construction Site
Runoff (MD)
Austin, Texas
Hamilton County, Ohio
Mean TSS (mg/L)
Mean Inflow TSS
Concentration
(mg/L)
17,500
3,502
1,087
359
4,623
625
415
2,670
9,700
1,500-4,500
1,000-5,000
4,200
600
2,950
3,681
Source
Horner, Guerdy, and Kortenhoff 1990
Horner, Guerdy, and Kortenhoff 1990
Horner, Guerdy, and Kortenhoff 1990
Schueler and Lugbill 1990
Schueler and Lugbill 1990
Schueler and Lugbill 1990
Schueler and Lugbill 1990
Schueler and Lugbill 1990
Jarrett 1996
Sturm and Kirby 1991
Barfield and Clar 1985
York and Herb 1978
Dartiguenave, ECLille, and Maidment 1997
Islam, Taphorn, and Utrata-Halcomb 1998
N/A
N/A - Not Applicable
5.2.2. METALS
Many toxic metals can be found in urban stormwater, although typically only metals such as
zinc, copper, lead, cadmium, and chromium have been identified in the literature as being of
primary concern because of their prevalence in urban stormwater runoff and their potential for
environmental harm. These metals are generated by motor vehicle exhaust, weathering of
buildings, burning fossil fuels, atmospheric deposition, and other common urban activities.
Metals can bioaccumulate in stream environments, resulting in plant growth inhibition and
adverse health effects on bottom-dwelling organisms (Masterson and Bannerman 1994).
Generally the concentrations found in urban stormwater are not high enough for acute toxicity
(Field and Pitt 1990). Rather, it is the cumulative effect of the concentration of these metals over
time and the buildup in the sediment and animal tissue that are of greater concern.
Construction sites are not thought to be important sources of metals contamination. Runoff from
such sites could have high metals contents if the soil is already contaminated. Construction
activities alone do not usually result in metals contamination, although there is little data
available on this subject.
5.2.3. PAHs, AND OIL AND GREASE
Petroleum-based substances such as oil and grease and PAHs are found frequently in urban
stormwater runoff. Many constituents of PAHs and oil and grease, such as pyrene and
benzo[b]fluoranthene, are carcinogens and toxic to downstream biota (Menzie-Cura &
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Section 5: Selection of Pollutants for Regulation
Associates 1995). Oil and grease and PAHs normally travel attached to sediment and organic
carbon. Downstream accumulation of these pollutants in the sediments of receiving waters such
as streams, lakes, and estuaries is of concern.
Construction activities during site development are not believed to be major contributors of these
contaminants to stormwater runoff. Improper operation and maintenance of construction
equipment at construction sites, as well as poor housekeeping practices (e.g., improper storage of
oil and gasoline products and construction materials), could lead to leakage or spillage of
products that contain hydrocarbons.
5.2.4. PATHOGENS
Microbes are commonly found in urban stormwater. Although not all microbes are harmful,
several species such as the pathogens Cryptosporidium and Giardia can directly cause diseases
in humans. The presence of bacteria such as fecal coliform bacteria, fecal streptococci, and
Escherichia coli (i.e., E. coli) indicates a potential health risk. High levels of these bacteria can
result in beach closings, restrictions on shellfish harvest, and increased treatment for drinking
water to decrease the risk of human health problems.
Construction site activities are not believed to be major contributors to pathogen contamination
of surface waters. The only potential known source of pathogens from construction sites are
portable septic tanks used by construction workers. These systems, however, are typically self-
contained, although leaks or spills could result in releases.
5.3. SELECTION OF POLLUTANTS FOR REGULATION
When determining which pollutants to consider for regulation, the U.S. Environmental
Protection Agency (EPA) applied the following priorities for discharges from the C&D industry:
Focus on pollutants directly attributable to the industry, using indicator pollutants
where necessary
Focus on pollutants most commonly encountered under most settings, (i.e., not to
preconstruction site contamination issues or accidental discharges)
Focus on pollutants that are most manageable given the current suite of available
technologies
Focus on pollutants that can be addressed under the authority of effluent guidelines
In support of the 2002 and 2004 regulatory efforts, EPA conducted an extensive evaluation of the
literature to identify pollutants present in stormwater discharges from C&D sites. While the
literature contains extensive information on pollutants present in stormwater discharges from
urban areas, there were little data available on pollutants present in stormwater discharges from
construction sites during the active phase of construction other than for sediment, TSS, and
turbidity. This is not surprising, because construction site stormwater management is primarily
concerned with controlling solids from exposed soil areas. There is the potential for other
pollutants to be discharged from construction sites depending on factors such as prior land uses.
For example, if the prior land use was agriculture, there is the potential for discharge of
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Section 5: Selection of Pollutants for Regulation
pollutants such as nutrients and pesticides. Likewise, areas of redevelopment that occur on sites
where previous land uses included industry could discharge pollutants such as organics and
metals. In addition, pollutants such as metals and nutrients can be present in native site soils, and
could be discharged from construction sites. Also, high pH can result from stormwater being
exposed to freshly placed concrete. However, EPA was not able to identify sufficient data in the
literature to warrant development of controls specific to pollutants other than sediment, TSS, and
turbidity in stormwater discharges from active construction sites. Although EPA identified other
pollutants of concern for this industry, EPA did not develop regulatory options specifically
targeted at controlling each of these individual pollutants.
Instead, EPA chose to develop regulatory options using an indicator pollutant, turbidity. While
turbidity might not correlate well with TSS, design of management systems for controlling
turbidity will likely result in control of other pollutants such as TSS, nutrients, and metals that
are present in the solid-phase (attached to sediments). In addition, turbidity, unlike TSS, can be
measured with relative ease in the field using hand-held turbidity meters or automated in-line
turbidity meters. An in-line turbidity meter, coupled with a data logger, can offer real-time data
on turbidity levels in stormwater discharges.
Particles that contribute to turbidity can be of such a fine grain that they will not be removed by
the mechanisms whereby most best management practices operate, mainly settling and filtration.
Hence, EPA's proposal rule focuses on active treatment of stormwater runoff using polymers to
remove turbidity, as well as TSS and other pollutants. Section 7.1.6 discusses active treatment
systems designed to reduce and/or remove these fine colloidal particles.
5.4. REFERENCES
Barfield B.J., and M. Clar. 1985. Development of New Design Criteria for Sediment Traps and
Basins. Prepared for the Maryland Resource Administration. Annapolis, MD.
Dartiguenave, C.M., I. ECLille, and D.R. Maidment. 1997. Water Quality Master Planning for
Austin. CRWR Online Report. 97-6.
Goldman, S.J., K. Jackson, and T.A. Bursztynsky. 1986. Erosion and Sediment Control
Handbook. McGraw-Hill, New York.
Gray, J.R., D. Glysson, L.M. Turcios, and G.E. Schwarz. 2000. Comparability of Suspended-
Sediment Concentration and Total Suspended Solids Data. Water-Resources Investigation
Report 00-4191. U.S. Geological Survey, Reston, VA.
Field. R., and R.E. Pitt. 1990. Urban Storm-Induced Discharge Impacts: U.S. Environmental
Protection Agency Research Program Review. Water Science and Technology 22(10/11): 1-7.
Horner, R.R., J. Guedry, and M.H. Kortenhoff. 1990. Improving the Cost Effectiveness of
Highway Construction Site Erosion and Pollution Control. Washington State Transportation
Center and the Federal Highway Administration. Seattle, WA.
Islam, M.M., D. Taphorn, andH. Utrata-Halcomb. 1998. Current Performance of Sediment
Basins & Sediment Yield Measurement of Construction Sites in Unincorporated Hamilton
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Section 5: Selection of Pollutants for Regulation
County, Ohio. Prepared for Hamilton County Soil and Water Conservation District,
Cincinnati, OH.
Jarrett, A. 1996. Sediment Basin Evaluation and Design Improvements. Prepared for Orange
County Board of Commissioners by Pennsylvania State University, State College, PA.
Masterson, J.P., and R.T. Bannerman. 1994. Impacts of Stormwater Runoff on Urban Streams in
Milwaukee County, Wisconsin. In Proceedings of American Water Resources Association.,
National Symposium on Water Quality, Nov. 6-10, 1994, Chicago, IL. pp. 123-133.
Menzie-Cura & Associates. 1995. Measurements and Loadings ofPolycyclic Aromatic
Hydrocarbons (PAH) in Stormwater, Combined Sewer Overflow. MBP-95-06. Massachusetts
Bay Program, MA.
Schueler, T. 1997. Impact of Suspended and Deposited Sediment. Article 14 in The Practice of
Watershed Protection, eds. T.R. Schueler and H.K. Holland, pp. 64-65. Center for Watershed
Protection. Ellicott City, MD.
Schueler, T., and J. Lugbill. 1990. Performance of Current Sediment Control Measures at
Maryland Construction Sites. Metropolitan Washington Council of Governments,
Washington, DC.
Sturm, T.W., and R.E. Kirby. 1991. Sediment Reduction in Urban Stormwater Runoff from
Construction Sites. Georgia Institute of Technology. Atlanta, GA.
York T.H., and WJ. Herb. 1978. Effects of Urbanization andStreamflow on Sediment Transport
in the Rock Creek andAnacostia River Basins. Montgomery County, MD, 1972-1974. U.S.
Geological Survey Professional Paper No. 1003.
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Section 6: Limitations and Standards: Data Selection and Calculation
6. LIMITATIONS AND STANDARDS: DATA SELECTION AND
CALCULATION
6.1. INTRODUCTION
This section describes the data selection and statistical methodology used by the
U.S. Environmental Protection Agency (EPA) in calculating the proposed limitations for the
Construction and Development (C&D) point source category. As described in this section, the
proposed effluent limitations and standards are based on long-term average effluent values and
variability factors that account for variation in treatment performance within a particular
treatment technology over time. For simplicity, the following discussion refers only to effluent
limitations guidelines; however, the discussion also applies to new source standards.
EPA is proposing a daily maximum limitation for turbidity, and Section 6.2 briefly describes the
pollutant parameter. Section 6.3 provides an overview of EPA's criteria typically used to select
data sets for limitations presented in final rules (final limitations). Section 6.4 describes the
available discharge data and applies the criteria to select data as the basis of the proposed
limitation. Section 6.5 presents procedures for averaging data to obtain daily values used in the
limitations calculations. Section 6.6 provides an overview of the limitations, percentile basis,
calculations, monitoring, and compliance related to the limitations. Section 6.7 summarizes the
steps used to calculate the limitations. Section 6.8 provides references.
EPA also is considering a limitation on pH. Such a limitation would not be developed using the
statistical methodology described below. Instead, EPA typically establishes a range of acceptable
values from 6 to 9 standard units to protect against extreme acidity or alkalinity.
6.2. TURBIDITY
As described in Section 5, there are a number of pollutants associated with discharges from C&D
sites. EPA is proposing effluent limitations for turbidity, which is generally accepted as a good
measure of the presence of those pollutants and the quality of the stormwater being discharged
from the C&D site. Turbidity is an expression of the optical property that causes light to be
scattered and absorbed rather than transmitted with no change in direction or flux level through
the sample caused by suspended and colloidal matter such as clay, silt, finely divided organic
and inorganic matter, and plankton and other microscopic organisms. See Title 40 of the Code of
Federal Regulations (CFR) 136.3. The more total particulates in the water, the murkier it
becomes and the higher the turbidity measurement.
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Section 6: Limitations and Standards: Data Selection and Calculation
Turbidity is measured in nephelometric turbidity units (NTU). The instrument used for
measuring it is called nephelometer or turbidimeter, which measures the intensity of light
scattered at 90 degrees as a beam of light passes through a water sample. For turbidity, the
current CFR Part 1361 approved methods are based on nephelometric equipment: EPA Method
180.1 Rev 2.0 (USEPA 1993); Standard Methods (18th, 19th, 20th, and 21st editions) 2130 B;
ASTM D1889-94 (ASTM 1993); and USGS 1-3860-85 (USGS 1989). Nephelometers are
relatively unaffected by small differences in design parameters, and therefore, are specified as
the standard instrument for measuring low turbidities. Turbidimeters of nonstandard design, such
as forward-scattering devices, might be more sensitive than nephelometers to the presence of
larger particles but have not been generally approved by EPA for wastewater monitoring.
Regardless of the measuring equipment used, turbidity should be determined as soon as possible
after the sample is collected, because sample preservation is not practical. If storage is required,
refrigerate or cool to 4 degrees Celcius (°C) to minimize microbiological decomposition of
solids. For best results, measure turbidity without altering the original sample conditions such as
temperature or pH. Gently agitate all samples before examination to ensure a representative
measurement.
A turbidity measurement may be used to provide an estimation of the total suspended solids
(TSS) concentration. Engineering references (e.g., American Society of Civil Engineers (ASCE)
and American Water Works Association (AWWA) 2005) cite conversion factors for turbidity to
TSS values.
6.3. OVERVIEW OF DATA REVIEW AND CRITERIA
As described in Section 6.4, EPA qualitatively reviewed all the data before selecting a (large)
subset to calculate the proposed limitations. For the final rule, in addition to reviewing the data
used as the basis for the proposed limitations, EPA also will review data provided by
commenters and other sources. As part of this review for the final C&D limitations, EPA intends
to reevaluate its exclusions and inclusions of data and seek additional information about the sites
used as a basis for the proposed limitations. EPA also intends to apply following criteria in
determining if the proposal data and any additional data are appropriate to use as the basis for the
final rule. EPA has used these or similar criteria in developing limitations and standards for other
industries.
One criterion requires that the influents and effluents from the treatment components represent
typical wastewater from the industry, with no incompatible wastewater from other sources (e.g.,
sanitary wastes). Application of this criterion results in EPA selecting only those facilities or
sites where the commingled wastewaters did not result in substantial dilution, more concentrated
wastewaters, or wastewaters with different types of pollutants than those generated by C&D
wastewater. As part of this criterion, EPA also will consider whether to include concentration
data for wastewaters that were recycled for further treatment. For example, some sites may be
required to meet stringent water quality limits. If the treatment system does not meet some
1 EPA publishes laboratory analytical methods that are used by industries and municipalities to analyze the
chemical, physical, and biological components of wastewater and other environmental samples that are required by
regulations under the authority of the Clean Water Act. All these methods are published as regulations in the Code
of Federal Regulations (CFR) at Title 40 Part 136.
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Section 6: Limitations and Standards: Data Selection and Calculation
predetermined value, the treated waters can be recycled through the treatment system one or
more additional times to remove more solids before eventual discharge. As the basis for the
proposed limitation, EPA has excluded data reported to be during recycling periods. EPA does
not consider additional treatment necessary to comply with the national limitation, and thus, the
data would not be appropriate to use as a basis for the limitation. (However, if a site is subject to
local limits or other requirements, then it may be required to perform additional treatment to
meet those other requirements.)
A second criterion ensures that the pollutants were present in the influent at sufficient
concentrations to evaluate treatment effectiveness. To evaluate whether the data meet this
criterion, EPA might consider using a long-term average test for sites where EPA possesses
paired influent and effluent data. EPA has used such comparisons in developing regulations for
other industries (e.g., iron and steel point source category). The test looks at the influent
concentrations to ensure that a pollutant is present at sufficient concentration to evaluate
treatment effectiveness. If a pollutant fails the test (i.e., was not present at a treatable
concentration), EPA excludes the data for that pollutant at that facility from its long-term
average and variability calculations. Because the retention time of the treatment system is
relatively short, in developing the final rule, EPA also might consider excluding an effluent
concentration that corresponds to an influent concentration reported as zero NTU. By applying
the long-term average test and/or verifying that influent includes measureable solid content, EPA
would ensure that its limitations resulted from treatment and not simply the absence of turbidity
in the wastestream. If industry supplies EPA with effluent data but not the corresponding influent
data, EPA might choose to use the effluent data, if it is confident that turbidity would have been
present at high concentrations at the site. This approach would satisfy EPA's objective of
including as much data from as many sites as possible in its calculations.
A third criterion generally requires that the site demonstrate good operation of the model
treatment technology. EPA generally determines whether a site meets this criterion on the basis
of personal visits, discussions with site management, or comparison to the performance of
treatment systems at other sites. EPA often contacts sites to determine whether data submitted
were representative of normal operating conditions for the facility and equipment. As a result of
this review, EPA typically eliminates facilities that experience repeated operating problems with
their treatment systems. EPA also excludes data if the measurements have substantially greater
values or more variability than data from other sites. Section 6.6.6 describes a potential
application of this criterion.
A fourth criterion typically requires that the data cannot represent periods of treatment upsets or
shut-down periods. This criterion sometimes results in the exclusion of periods when the site first
starts operating the equipment (start-up). As result of this criterion, EPA could exclude certain
time periods and other outliers in the data from an otherwise well-operated site.
EPA has not included the size of the site as a criterion, because the site size and water flow
determine the size of the treatment system, rather than its performance.
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Section 6: Limitations and Standards: Data Selection and Calculation
6.4. DATA SELECTED AS BASIS FOR PROPOSED LIMITATIONS
The proposed long-term averages, variability factors, and limitations are based on data provided
by three sources. The following sections describe the data sources, summarize the data submitted
by the three sources, and present the results of EPA's data review.
6.4.1. DATA SOURCES
EPA evaluated more than 6,600 turbidity measurements in determining the basis for the
proposed limitation. The data were from 19 treatment systems at 17 sites in three states. The data
were provided by two vendors (Clear Creek Systems, Inc., and Cascade EcoSolutions) and a
state environmental agency (Oregon Department of Environmental Quality [ODEQ]). Table 6-1
identifies the data sources, the site name or location, and the abbreviations used to identify the
sites throughout Section 6 and the data listings in Appendix G. For two sites, 4 and WLCPO,
each with two treatment systems, the abbreviation is appended with ,5757 or SYS2 to distinguish
between the systems.
Table 6-1. Data Sources and Site Identification
Source
Clear Creek Systems, Inc.
Cascade EcoSolutions
Oregon Department of
Environmental Quality
Site name or location
California, Oregon, and Washington
Beacon Hill Reservoir Burying Project
Brightwater Waste Water Treatment Plant
WSDOT SR-522 Road Improvement Project (Elliot Road)
Lakeside
Seatac Airport
Sound Transit Central Link Light Rail
West Linn Corporate Park
Hoodview Estates
Abbreviation
2
3
4
6
8
11
BZR08
SC05
SC08
BHRBP
BWWTP
ELLRD
LSIDE
SEAAIR
STCLLR
WLCPO
HEO
6.4.1.1. Clear Creek Systems, Inc.
Clear Creek Systems, Inc., is a vendor that designs, installs, and monitors treatment systems for
stormwater and construction runoff. The vendor provided influent and effluent measurements
from nine sites in three western states: California, Oregon, and Washington. The influent
measurements were taken from the stormwater running off the construction site before being
treated. The effluent measurements are from the stormwater treated with EPA's model
technology. (Gannon 2008a, 2008b, 2008c, 2008d). The vendor did not provide any additional
information about the sites (e.g., exact location, site size, typical rainfall). It identified the sites as
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Section 6: Limitations and Standards: Data Selection and Calculation
2, 3, 4, 6, 8, 11, BZR08, SC05, and SC08. Site 4 had two treatment systems and EPA analyzed
the data separately for each system as explained in Section 6.5.2.
6.4.1.2. Cascade EcoSolutions
A second vendor, Cascade EcoSolutions, provided data for six sites in Washington State. The
vendor provides the chitosan-based flocculants used by service providers to treat turbid
stormwater.
For three sites, the vendor provided turbidity measurements via a ChitoVan Performance Review
Data Set (Cascade EcoSolutions 2008) without specific details about the treatment and sites. It
identifies the three sites as Beacon Hill Reservoir Burying Project, Brightwater Waste Water
Treatment Plant, and Sound Transit Central Link Light Rail. All three are in the Seattle,
Washington, area.
For the other three sites, the vendor provides detailed information about the treatment and sites in
an engineering report (Minton 2006). The vendor provided a separate Engineering Report Data
file (Cascade EcoSolutions 2008) corresponding to the three sites described in the report. The
specifications with regard to effluent quality for the three sites are to "achieve performance goals
of a minimum of 95% reduction of NTU turbidity, a maximum discharge of 10 NTU turbidity,
and a discharge pH within a range of 6.5-8.5. If these values are exceeded at any time the
responsible site operating personnel shall immediately take appropriate corrective actions"
(Minton 2006 page 26). When the data did not meet the specifications, they were automatically
recycled. Pages 9 to 11 of the report describes the treatment system in more detail:
Chitosan-Enhanced Sand Filtration is a stand-alone treatment technology for
stormwater from construction sites. Chitosan acetate coagulates fine suspended
sediments, producing larger particles, enhancing their retention by the treatment
system. . . .
Stormwater is initially retained in a holding basin, which serves two functions. It
provides pretreatment by one and possible two modes. The common pretreatment
mode is simple gravity settling of sediment entering with the untreated
stormwater.
System components
The second pretreatment mode is the addition of chitosan acetate as the
stormwater enters the basin. This is done only if the incoming stormwater is
extremely turbid, in excess of 600 NTU and if all source control measures have
been found incapable of reducing the turbidity below that value. The second
function is to equalize the flow rate. Moderating the incoming flow allows the
CESF-FT to operate at an essentially constant flow rate.
The filters are periodically backwashed automatically to remove filtered sediment
from each pod to maintain the hydraulic capacity of the sand. This feature allows
the treatment system to operate on a continuous flow-through basis. As shown in
Figure 1 [not reproduced in this document], the system typically has four filter
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Section 6: Limitations and Standards: Data Selection and Calculation
pods. The system is equipped with automated sensors for turbidity and pH. If the
discharge requirements are not met for either, the treated stormwater is recycled
to the holding basin, to receive treatment again. Chitosan acetate is added
immediately before the filters.
The CESF-FT consists of these components.
Stormwater holding basin(s): Alternatively called the detention/pretreatment
basin, these may be either temporary or an element of the permanent drainage
system (i.e., detention basin), and may be either ponds or mobile storage tanks.
Pretreatment: Axiomatic to the treatment system is good site erosion control.
The objective is to keep the turbidity of the untreated stormwater less than 600
NTU. When the turbidity of the stormwater entering the holding basin exceeds
this value, chitosan acetate is added as the stormwater enters the basin or a
pretreatment tank that follows the basin. The latter has been the more common
practice. The pretreated water then enters the basin or tank where the coagulated
sediment settles.
Influent pump: Stormwater is pumped from the holding basin to the filter units.
Liqui-Floc injection system: Consists of the following: precision, variable output
metering pump, feed and suction tubing, Liqui-Floc product storage container.
Discharge piping or structure: Site and flow rate specific.
Sand filtration units: Various sizes and capacities are shown in Table 1 (NSS,
2004b). The sand size specification (NSS, 2004b) is presented in Table 2,
consistent with Ecology (2003b, 2004) requirements. The filters are operated in
the range of 5 to 10 GPM/ft2 of media. Eighteen (18) inches of sand is used.
Backwash system: The sand filters are periodically backwashed to retain their
hydraulic capacity. The frequency of backwashing is controlled by a timing
mechanism, causing backwashing to occur on a regulator schedule. The control
system also contains a default value for pressure loss through the filter. If the
default value is reached before the preset time has passed, backwashing occurs.
This commonly indicates a need to inspection and possibly maintenance of the
filters.
Backwash holding tank: The dirty backwash water does not directly enter the
holding basin. Rather, it first enters either a small cell located in the holding basin
(separated from the remainder of the basin by a silt curtain) or a separate tank.
This keeps most of the filtered sediment from entering the larger basin.
Influent and effluent turbidity and pH monitoring units: These meters
continuously sample the influent and effluent, and directly control the recycle
valve. Data are stored.
Page 6-6
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Section 6: Limitations and Standards: Data Selection and Calculation
Recycle system: If either the effluent turbidity or pH meter indicates that the
quality of the effluent has strayed outside the specified discharge requirements, a
value automatically shifts to recycle the stormwater back to the holding basin.
Action is then taken to redress the cause.
The report also provides a detailed description of the three sites:
Lakeside Housing Development ("LSIDE")
The project was located immediately east of NE 65th and 188th Lane NE. in
Redmond. Stormwater from the site normally drains east to a natural wetland,
then to Evans Creek. However, because of the sensitive nature of Evans Creek, all
treated stormwater generated during the construction period was pumped to the
SR 202 stormwater drainage system, which discharges directly to Lake
Sammamish. The CESF-FT facility at the Lakeside Housing Project did not
require pretreatment
All stormwater runoff from disturbed portions of the site was directed, via open
channels and storm drains, to the stormwater holding basin, which has a capacity
of approximately 1 million gallons. Treated water from the CESF-FT facility was
directed to two treated water holding tanks so that the water could be tested prior
to discharge.
Chitosan (1% solution of chitosan acetate) was injected into a 6-inch pipe about
50-feet upstream of the sand filter at 0.3 to 0.8 milligrams per liter (mg/L),
varying with the turbidity of the water. The dose rate of chitosan was calibrated
by timing the uptake of chitosan (through the metering pump) from a graduated
cylinder and noting the flow rate of water from the sand filter. (Page 13 Cascade
EcoSolutions 2008)
SeaTac International Airport Third Runway ("SEAAIR"):
Over 14 million cubic yards of fill dirt are being brought to the west side of Sea-
Tac International Airport to form the foundation for the new runway, distributed
on 150 acres. There are seven individual CESF-FT units placed at four separate
locations, each with holding basins. Their combined capacity is 3,500 GPM.
Stormwater can be pumped between ponds to maximize the use of the total
capacity of the units. Discharge is to Miller Creek.
Stormwater runoff commonly enters the holding basins at a turbidity level above
1,000 NTU, sometimes as high as 3,000 NTU. The Conditional Use Designation
document (Ecology, 2004) limits the chitosan acetate dose rate to 1 mg/L. The
contractor was able to keep the dosage within 1 mg/L, despite the high turbidity,
by splitting usage between pretreatment and treatment before the filters. At this
site, pretreatment occurred in a pretreatment tank immediately following the
holding basin, not in the holding basin. (Page 14 Cascade EcoSolutions 2008)
The recycle volume for Unit 4 at the SeaTac Airport site ranged from 17 to 27%
during the first three months of operation (December 2004 through February
Page 6-7
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Section 6: Limitations and Standards: Data Selection and Calculation
2005). The startup of the Airport site was complex because of the number of
systems involved, the short time frame within which the systems had to be
installed, and the occurrence of an extreme storm event that nearly exceeded the
total capacity of the treatment systems. The most serious mechanical problem was
due to the internal corrosion of the chitosan storage tanks, which caused small
pieces of corrosion debris to clog the chitosan metering pumps stopping the flow
of the treatment agent. When the chitosan stopped flowing the treatment failed
and the systems went into recycle mode while operators dismantled and cleaned
the metering pumps. This problem was repeated frequently until the chitosan
storage tanks were replaced with non-corrosive tanks. Once this problem was
corrected the systems ran as designed and no further problems were encountered.
(Pages 30-31 Cascade EcoSolutions 2008)
WSDOT SR-522 Road Improvement Project (Elliot Road, "ELLRD"):
The Washington Department of Transportation (WSDOT) is widening SR-522
between the Echo Lake Road and a bridge across the Snohomish River. The
project site is about 125 acres: Discharge is to the Snohomish River. . . . Two 500
GPM units were deployed, one each at the Echo Lake interchange and at Elliott
Readjust south of the bridge over the Snohomish River.
Turbidity levels of incoming stormwater varied significantly, less than 60 NTU to
greater than 1,400 NTU. High turbidities were due to the frequent blasting of
shale on the project site. Therefore, chitosan acetate was added to the high-
turbidity stormwater immediately prior to the holding basin. It was effective,
typically reducing the turbidity in the basin to less than 60 NTU. Ecology (2003b,
2004) limits the dose rate to 1 mg/L. A variance was requested for this site,
allowing an aggregate dosage of 3 mg/L, but with 1 mg/L remaining as the
immediate dosage before the filters. In practice, about 2.5 mg/L was used in
pretreatment when required, added as the runoff entered the basin, and 0.5 mg/L
was used immediately prior to the sand filters.
Disturbance of the sedimentary shale rock created a high pH (as high as 9.6) in
dewatered groundwater and stormwater. Liquid carbon dioxide was added at the
pretreatment station to control pH as it entered the basin. Another adverse
condition was extensive algal blooms occurring in the basin. The atypical growth
of algae increased the pH of the stored stormwater, necessitating the placement of
carbon dioxide as dry ice in the basin. The algae growth was the result of a
combination of low turbidity (with pretreatment), sunlight penetration, and
elevated phosphorus concentrations. The latter was believed due blasting
explosives. The treatment system removed the algae from the water without
damage to the filters. (Pages 16-17 Cascade EcoSolutions 2008)
The SR522 site reflected what may be the most extreme site conditions that the
CESF-FT system will experience. Difficulties were faced throughout the
treatment period, not just during startup.
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Section 6: Limitations and Standards: Data Selection and Calculation
The pH varied from 6.5 to 9.5 based due to the nature of site work and algal
production in the holding basin.
The turbidity varied rapidly from nearly clean to above several thousands
NTU.
The volume of water occasionally exceeded the system's capacity, particularly
when the turbidity was very high. Pretreatment became a critical factor.
The considerably higher recycle times on the WSDOT SR522 project reflect the
fact that this difficult site required times where the system was intentionally put
into recycle while dosing with chitosan in an effort to reduce the turbidity of the
holding basin before treatment. Because of the nature of the project (linear
highway project) there were times when the turbidity rose to thousands of NTU
without warning. During these times the only way to reduce the turbidity was to
recycle the water while adding chitosan.
The Consultant noted during the field visit that while there is a flow meter on the
discharge line, the data are not recorded. There is therefore no direct record that
recycle occurs each time the discharge limits are not met. Rather, it is presumed
that it occurs based on the records of the turbidity and pH, measured immediately
in the discharge of the filter system, and the activation of the alarm system. The
above calculations were made through the examination of the record on turbidity
and pH. Where either or both parameters were outside the discharge
specifications, it was presumed that recycle occurred. Since recycle occurs
automatically, it can only be presumed that the recycle valve functioned
satisfactorily in all instances. For this reason, the Consultant has recommended
that the discharge flow be recorded (Page 31 Cascade EcoSolutions 2008).
Additional information about SeaTac and ELLRD:2
If a pH or turbidity excursion causes the system cause to go into recycle, the
operator measures the parameters to determine which is out of compliance. If the
pH is too low, the system is kept in recycle while food-grade sodium bicarbonate
is added. If the holding pond is large, this may require shutting down the system,
and mixing water in the pond with pumps until the desired pH is achieved. The
system is restarted in recycle mode. Once the pH is within acceptable limits the
system is put back on line. If the pH is too high, dry ice is hand broadcast into the
holding pond until the pH is acceptable. If high pH continues (e.g. extensive
concrete pouring), an automated liquid carbon dioxide injection system may be
installed. This system reads the incoming and outgoing pH, and automatically
adjusts the rate of carbon dioxide injection. Such a system was installed for a
period of time on the WSDOT SR522 project due to the high pH caused by the
disturbance of alkaline sedimentary shale material by construction.
" Page 23 notes that turbidity and pH were not monitored continuously at the Lakeside site.
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Section 6: Limitations and Standards: Data Selection and Calculation
If the turbidity exceeds the preset limits, one of three adjustments are made:
increasing the chitosan dose in a pretreatment settling tank, reducing the flow rate
of the system to allow more settling time, or more extensive treatment. If, for
example, the holding pond suddenly experiences a significant increase in turbidity
due to site work or heavy precipitation, the common adjustment is to continue in
the recycle mode while additional chitosan is added to the stormwater as it enters
the basin. If this approach is not adequate due to extreme turbidity the system is
shut down, pumps recirculate the entire holding pond contents while adding
chitosan to reduce the turbidity to levels consistent with filtration (<500 NTU). If
this approach is necessary, Department of Ecology and the project contractor are
contacted. A plan is developed consistent with Ecology's regulations and project
needs. Typically a quantity of additional chitosan is estimated based on jar
testing; that quantity is added while recirculating (mixing) the holding pond with
pumps. Once the turbidity has been reduced to acceptable levels the system is
restarted in the recycle mode until it has been determined that the effluent
turbidity limits can be met. Once this occurs the system is put back on line.
Normally, the holding pond is tested for residual chitosan to ensure there is no
excess chitosan present. The actions are documented in a report, summarizing the
cause of the problem and the methods used to bring the system back into
compliance. (Page 21 Cascade EcoSolutions 2008).
6.4.1.3. Oregon Department of Environmental Quality
ODEQ was the source for two other sites: the West Linn Corporate Park and Hoodview Estates.
Both are in Oregon. The West Linn Corporate Park has two treatment systems, and EPA
analyzed the data separately for each system as explained in Section 6.5.2. The ODEQ Web site
(lurries no date) describes each site:
West Linn Corporate Park ("WLCPO"):
Approximately 24.0 acres of land on slope with minimal overburden on bedrock
drained to the Blankenship Road roadside ditch. This ditch then drained into a 48"
diameter pipe drain that discharged the storm water into the 1-205 roadside
drainage ditch at the end of 13th Street, where it terminated in a cul-de-sac next to
the 1-205 freeway. Sandbags in the end of the 48" diameter pipe prevented the
turbid storm water from discharging into the roadside ditch. Two pumps in
parallel picked up the storm water and delivered it to the first Frac tank for the
addition and mixing of the flocculant. Sumalchlor 50, manufactured by Summit
Research Labs, was the flocculant selected due to its relative ability to be pH
insensitive and showed rapid settling in lab tests. Sumalchlor-50 is an inorganic
coagulant with a short residence life in the water being treated and the aluminum
compounds will quickly hydrolyze to form inert aluminum hydroxide...
A 1 year, 24 hour storm with a total rainfall of 1" was the design storm event for
this system. A review of PDX rainfall data for March through June, 1992-1996,
found that of the 610 days in these months, only twice was there more than 1" of
rainfall in 24 hours. This storm generated a peak-anticipated flow of 1.28 cfs (575
gallons per minute) at the outfall of the 48" pipe. Utilization of the 48" pipe as a
Page 6-10
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Section 6: Limitations and Standards: Data Selection and Calculation
detention pipe allowed the peak pumping requirements to be approximately 300
gpm without overflowing the sandbags.
The first Frac tank was the place where coagulation and flocculation took place.
The prescribed amount of the flocculant was injected and mixed the water for a
set time in a 17,000-gallon Frac tank. This system was controlled by input volume
and had the capacity to mix and treat approximately 500 gpm.
Pumps were used to evacuate the mixed storm water and distribute it to the
settling tanks. The extraction system at 450 gpm was designed to exceed the input
capability.
Two baffled 17,000-gallon Frac tanks, which received the water from the mixing
tank were used for settling. These tanks allowed soil particles to settle and clean
water to discharge via gravity from a four-inch outlet, located approximately four
and one-half feet above the bottom of the tank. The discharge was piped into the
adjoining stream. Discharge sampling was conducted at this point.
Hoodview Estates ("HEO"):
In 2000, another similar system was installed on the Hoodview Estates [emphasis
added] site off SW Salamo Road in West Linn. This system used only a single
tank for adding and mixing the flocculant. The underground water quality
detention tank was used for upstream detention and a pond was used for settling
after the tank. The discharge from the pond was to a stream, which discharged
into Tanner Creek.
6.4.2. SUMMARY OF DATA SUBMITTED FOR REVIEW
Table 6-2 provides a summary of the reported turbidity measurements in effluent from the 19
systems at the 17 sites. EPA received more than 6,600 measurements of turbidity, and they are
provided in Listing 1 of Appendix G. (DCN 45054 provides the data in an electronic spreadsheet
file.)
As a first step in developing a database for further review, EPA excluded data points that
appeared to be typographical errors or reported in an unusual format. These values were not
included in any summaries or listings in this technical development document. The vendor has
resolved most of the discrepancies (Gannon 2008d), and EPA will incorporate his corrections
during its data review for the final limitations. In particular, EPA excluded the following:
Typographical errors:
o Site 4 (System #2): ".3.4" (1/9/2005)
o Site 11: ".6.87" (12/29/2004). (According to the vendor, the value should be
6.87.)
Page 6-11
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Section 6: Limitations and Standards: Data Selection and Calculation
Data with unusual formats were excluded. This format resulted in some cells in the
spreadsheet having more than one measurement. The vendor states that EPA should
use the first number and delete the one after the slash:
o Site 2: ".88/6.5" (1/6-7/2005), "1.76/6" (1/8/2005).
o Site 11: 104 effluent measurements specified as two numbers separated by a
slash, such as "1.52/.86". These types of measurements were most prevalent on
the following dates: 1/21/2005, 2/17/2005, and 2/19/2005 through 3/3/2005.
EPA then examined the remaining reported values. As shown in the summary in Table 6-2, there
were 6,537 measurements ranging from a reported value of zero (at several systems) to 1,936
NTU (at Site 2). The arithmetic averages at each system ranged from 0.46 (SC05) to 21.38 NTU
(HEO).
Table 6-2. Summary of Reported Turbidity Measurements (NTU) in Effluent
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
ALL
Number of
measurements
1,067
106
87
82
66
99
411
493
104
38
2,081
3
714
30
124
813
203
9
7
6,537
Arithmetic
average
4.85
1.93
2.05
2.92
4.72
12.15
4.09
1.17
1.87
1.11
6.90
21.38
3.07
0.46
1.19
3.62
0.66
19.48
14.66
4.58
Standard
deviation
60.29
3.45
4.28
6.26
9.24
13.21
6.94
1.53
0.81
1.07
13.13
6.44
0.98
0.34
1.26
8.24
0.71
12.22
10.08
25.88
Minimum
0.2
0
0.08
0.17
0.1
0.37
0
0
0
0.21
0.13
13.95
0.76
0.03
0.033
0.37
0
4.9
1
0
Median
1.62
0.96
0.69
0.94
1.96
8.44
1.36
0.6
1.9
0.83
3.42
25
3.17
0.34
0.71
1.32
0.5
19.5
19.87
1.93
Maximum
1,936
26
23
40
46.5
71.6
38.7
9.2
6
6.5
164.06
25.2
5.18
1.85
7.3
93.66
5.7
36.1
24.5
1,936
In addition to the effluent measurements, Listing 1 in Appendix G provides influent
measurements for reference and comparison purposes. Also, as explained in Section 6.3, EPA
might consider the influent concentrations for each system in selecting data sets for the final rule.
The influent values are measurements of the stormwater running before treatment. By comparing
the influent and effluent values, EPA can evaluate the effectiveness of that treatment system. In
creating a summary of the listing in Table 6-3, EPA incorporated the following changes:
Influent measurements of "1000+" (Sites 6 and SC08) and "over 1000" (Site 8) were
set equal to 1,000.
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Section 6: Limitations and Standards: Data Selection and Calculation
An influent measurement of "44.6.5" (Site 4) was set equal to 44.6.
Influent measurements of "90-10" (Site 4 on 1/17/2005) and "246/306" (Site BZR08
on 1/25/2008) were excluded.
Influent measurements reported as zero NTU were excluded. For the final rule, EPA
also might consider excluding the effluent values associated with zero NTU
concentrations in the influent.
Influent values of 99.9 NTU were left unchanged, but they indicate a maximum reading on the
turbidity meter, and thus, the concentrations are likely to have been greater than 100 NTU.
Table 6-3. Summary of Reported Turbidity Measurements (NTU) in Influent
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
ALL
Number of
measurements
24
37
22
22
12
15
65
490
104
7
1,730
3
714
6
62
335
196
9
9
3,862
Arithmetic
average
2,720.9
130.0
409.4
409.4
549.4
586.2
159.9
50.0
113.6
330.4
42.1
604.0
253.1
255.5
767.8
104.7
66.0
194.5
194.5
131.7
Standard
deviation
1,329.7
109.8
269.0
269.0
234.4
326.8
147.8
71.0
57.4
94.6
37.5
121.7
139.3
51.9
201.0
30.7
46.6
131.2
131.2
276.3
Minimum
853
6.6
10.2
10.2
209
204
1.08
0.3
2.7
149
1.82
466
44
210
234
24.51
4.7
78.1
78.1
0.3
Median
2,124
99.9
452.5
452.5
516.5
473
142
32.9
135.3
348
33.2
650
223.5
230.5
742
107.14
57.3
136.1
136.1
63.6
Maximum
4,816
381
985
985
1,000
1,000
1,020
709.9
284
420
182.77
696
917
331
1,536
201.44
293.9
472
472
4,816
6.4.3. DATA REVIEW AND EXCLUSIONS
This section describes EPA's review of the data, identifies data issues, and explains the rationale
for excluding certain data points from the limitations calculations. EPA focused its review on the
performance and operating conditions of the treatment systems. By applying the criteria
described in Section 6.3, EPA excluded values from eight systems that may not represent typical
wastewater from the industry, did not demonstrate good operation of the technology, or were the
result of upsets (criteria 1, 3 and 4).
Page 6-13
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Section 6: Limitations and Standards: Data Selection and Calculation
EPA considers recycled wastewater to differ from typical influents from this industry (criterion
1). As a consequence, EPA excluded effluent data reported to be during recycle modes:
350 effluent measurements from Site ELLRD. These types of measurements were
most prevalent on the following dates: 5/20/2005, 5/21/2005, and 5/23/2005 through
5/27/2005.
62 effluent measurements from Site SEAAIR. These types of measurements were most
prevalent on the following dates: 4/1/2005 and 4/16/2005.
For the final rule, EPA will reevaluate its assumption for values reported as zero. If the values
indicate measurements below detection, EPA may use one of the alternative statistical methods
described in Appendix I to model the mixture of detected and non-detected measurements. For
the proposal, EPA considered zero values to be associated with shutdown periods (criterion 4),
and thus, excluded:
Four zero values from Site 3 on 1/1/2005. The next lowest measurement at this site
was 0.04 NTU on 1/3/2005.
One zero value from Site 11 on 2/17/2005. The next lowest measurement at this site
was 0.21 NTU on 1/22/2005.
85 zero values from Site BHRBP. The next lowest measurement at this site was 0.2
NTU.
Seven zero values from Site BWWTP. The next lowest measurement at this site was
0.6 NTU on 3/2/2007.
22 zero values from Site STCLLR. The next lowest measurement at this site was 0.1
NTU.
EPA considers extreme values to be associated with treatment upset (criterion 4) or less than
optimal treatment (criterion 3), and thus excluded three values from Site 2:
1,936 NTU on 11/9/2004. EPA retained the other five measurements reported on this
day that all had values less than 17 NTU.
355 NTU on 1/29-30/2005. EPA retained the other six measurements reported for this
time period that all had values less than 4 NTU.
87 NTU on 4/1/2005 that was the only measurement reported for the day. It was over
three times higher than the next highest measurement (26.4 NTU on 11/8/2004) at the
site.
In calculating the proposed limitations, EPA retained the following data measurements that
appeared to be questionable. EPA intends to reevaluate their inclusions and/or correct the values
before calculating the final limitations:
Site 2: Several entries on 3/23/2005 are single integers and "5" is repeated seven
times. Other measurements for this site generally were reported with one or more
decimal places, not integer values. (According to the vendor, the values are in error.
Page 6-14
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Section 6: Limitations and Standards: Data Selection and Calculation
Because the dataset also include the corrected values, EPA will exclude the integer
values during its data review for the final rule.)
Site SC08: The value on 2/13/2008 appears as "0.033" (The vendor confirmed that
the correct value is "0.33" NTU.)
Table 6-4 summarizes the data after EPA's review and exclusions. These data were used as the
basis of the proposed limitations, the other tables in Section 6, and Listing 2 in Appendix G.
(DCN 45054 provides the data in an electronic spreadsheet file.) From the original set of more
than 6,600 measurements, EPA retained 6,003 measurements after incorporating the data
exclusions described in this section and Section 6.4.2. The 6,003 data values range from 0.033
(Site SC08) to 71.6 (Site 8). The arithmetic average is 2.87.
Table 6-4. Summary of Reported Turbidity Measurements (NTU) in Effluent
(After All Reviews)
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
ALL
Number of
measurements
1,064
102
87
82
66
99
410
408
97
38
1,731
3
714
30
124
751
181
9
7
6,003
Arithmetic
average
2.63
2.00
2.05
2.92
4.72
12.15
4.10
1.42
2.00
1.11
3.26
21.38
3.07
0.46
1.19
1.76
0.74
19.48
14.66
2.87
Standard
deviation
3.15
3.50
4.28
6.26
9.24
13.21
6.94
1.58
0.66
1.07
2.41
6.44
0.98
0.34
1.26
1.67
0.71
12.22
10.08
3.93
Minimum
0.2
0.04
0.08
0.17
0.1
0.37
0.21
0.2
0.6
0.21
0.13
13.95
0.76
0.03
0.033
0.37
0.1
4.90
1
0.033
Median
1.61
1
0.69
0.94
1.96
8.44
1.36
0.8
1.9
0.83
2.78
25
3.17
0.34
0.71
1.24
0.6
19.5
19.87
1.8
Maximum
26.4
26
23
40
46.5
71.6
38.7
9.2
6
6.5
9.99
25.2
5.18
1.85
7.3
9.49
5.7
36.1
24.5
71.6
6.5. DATA AVERAGING PRIOR TO LIMITATION CALCULATIONS
The proposed limitations for turbidity, as presented in today's notice, are provided as the
maximum daily discharge limitation. Definitions provided in 40 CFR 122.2 state that the
"maximum daily discharge limitation" is the "highest allowable daily discharge'' "Daily
discharge" is defined as the 'discharge of a pollutant' measured during a calendar day or any 24-
hour period that reasonably represents the calendar day for purposes of sampling.
Page 6-15
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Section 6: Limitations and Standards: Data Selection and Calculation
The data sources sometimes provided more than one measurement for a single day from a
treatment system. To obtain data that are appropriate for calculating limitations, EPA generally
averages the data to obtain a single value for each day at the treatment system. This section
describes EPA's conventions for using multiple measurements at each treatment (Section 6.5.1),
from multiple systems at a single site (Section 6.5.2), and field duplicates (Section 6.5.3).
6.5.1. DAILY VALUES FOR EACH TREATMENT SYSTEM
To be consistent with the daily discharge definition, EPA arithmetically averaged all
measurements (i.e., 6,003 from Table 6-4) recorded for each uniquely reported time period (e.g.,
12/21/2004, 12/21-22/2004) from each treatment system before calculating the proposed
limitations. EPA refers to this averaged value as the daily value. When the date was reported as a
range of consecutive dates (e.g., 12/21-22/2004), EPA assumed that the data had been reported
for a single 24-hour period and calculated a single daily value for the range. In this example, the
site would have two daily values for an overlapping period: one value for 12/21/2004 and
another for 12/21-22/2004. EPA might modify this approach for the final rule so that no values
are associated with overlapping time periods.
Listing 2 of Appendix G identified the 466 daily values obtained from arithmetically averaging
the 6,003 values summarized in Table 6-4. Table 6-5 provides a summary of the daily values.
From the 19 treatment systems at the 17 sites, EPA observed a minimum daily value of 0.08
(Site 4, system #1) to a maximum of 38.75 NTU (Site 8).
Table 6-5. Summary of Daily Values of Turbidity (NTU) in Effluent
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
ALL
Number of
daily values
131
21
19
19
18
18
42
23
8
9
19
3
75
6
13
9
17
9
7
466
Arithmetic
average
2.77
1.75
2.80
4.03
4.00
12.24
3.74
1.52
2.05
1.26
3.37
21.38
3.02
0.42
1.25
1.73
0.88
19.48
14.66
3.70
Standard
deviation
2.80
1.96
5.39
7.56
7.19
12.67
4.52
1.37
0.89
0.50
1.02
6.44
0.79
0.13
0.74
0.67
0.59
12.22
10.08
5.72
Minimum
0.35
0.45
0.08
0.46
0.38
0.40
0.55
0.33
0.90
0.57
1.76
13.95
1.16
0.30
0.65
0.52
0.42
4.90
1.00
0.08
Median
1.91
1.00
0.77
1.23
2.29
7.87
2.14
1.13
1.94
1.10
3.24
25.00
3.10
0.41
1.08
1.83
0.64
19.50
19.87
2.07
Maximum
15.78
7.63
23.00
33.20
32.25
38.75
23.21
6.28
3.97
2.21
5.23
25.20
4.82
0.61
3.34
2.51
2.17
36.10
24.50
38.75
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Section 6: Limitations and Standards: Data Selection and Calculation
6.5.2. MULTIPLE TREATMENT SYSTEMS
While the other sites had data for a single treatment system, Site 4 and Site WLCPO each had
two different treatment systems (or lines). In calculating the proposed limitations, EPA analyzed
the data from each treatment system separately. This is consistent with EPA's practice for other
industrial categories. As a consequence of EPA's review of the data for the final rule, EPA might
continue to consider each treatment system separately, or might determine that the measurements
at the two treatment systems should be averaged for each day to produce one value for each site.
For the final rule, EPA also intends to consider the vendor's recommendation of selecting the
maximum value from the reported measurements for the multiple lines during the same time
period (Gannon 2008d). One consideration will be the impact on variability estimates. For
example, it is possible that selecting the maximum value would decrease the variability estimates
such that they might not represent typical operations.
For sites with flow values corresponding to the individual measurements, EPA also might
consider flow-weighting the two treatment systems in calculating the daily average to give more
weight to the larger system to better represent the site conditions.
The following example calculates a flow-weighted value for Day 1 at Site X with two treatment
systems. The data are as follows:
Day
1
1
Treatment
system (i)
1
2
Concentration
(NTU)
10
0.1
Flow
(gpm)
1
100
The flow-weighted value for Day 1 is then calculated as follows:
Day 1 Value =
^concentration x flow
tf _ (W NTU x I gpm) + (O.I NTU x WO gpm)
1 gpm + WO gpm
= 0.198 NTU
The resulting flow-weighted daily value is equal to 0.198 NTU. If EPA instead had selected the
maximum value, the daily value of 10 NTU would have been selected from the stream with a
relatively small portion of the site's discharges. Alternatively, if EPA had selected an arithmetic
average without regard to the disparity in flows, the daily value would have been 5.05 NTU, a
turbidity level that is 50 times greater than the vast majority of the site's discharge. In contrast,
the flow-weighted value might better portray the overall discharge from the site by accounting
for the relative impact of each stormwater stream.
6.5.3. FIELD DUPLICATES
Although the measurements used for the proposed limitations did not include any field
duplicates, EPA realizes that industry may provide such measurements for EPA's consideration
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Section 6: Limitations and Standards: Data Selection and Calculation
for the final rule. Field duplicates are two samples collected for the same sampling point at
approximately the same time, flagged as duplicates for a single sample point, and measured
separately. Because the analytical data from each duplicate pair characterize the same conditions
at that time at a single sampling point, EPA typically averages the data to obtain one data value
for those conditions.
6.6. LIMITATIONS
The proposed limitations for turbidity, as presented in today's notice, are provided as the
maximum daily discharge limitation. This section describes the statistical percentile basis of the
limitation (Section 6.6.1), the concepts and calculations for the long-term average and the
variability factor (Sections 6.6.2 and 6.6.3), calculation for the limitation (Section 6.6.4),
engineering review of the results (Section 6.6.5), importance of comments in determining the
value of the final limitation (Section 6.6.6), monitoring considerations (Section 6.6.7), and
compliance with the final limitations (Section 6.5.8).
6.6.1. STATISTICAL PERCENTILE BASIS FOR LIMITATIONS
The daily maximum limitation is an estimate of the 99th percentile of the distribution of the daily
measurements. EPA calculates the daily maximum limitation on the basis of a percentile chosen
with the intention, on one hand, to accommodate reasonably anticipated variability within the
control of the site and, on the other hand, to reflect a level of performance consistent with the
Clean Water Act requirement that these effluent limitations be based on well-operated and
maintained facilities. The percentile for the daily maximum limitation is estimated using the
product of the long-term average and the variability factor. For the proposed rule, EPA estimated
the long-term average and variability factor using a statistical model based on the lognormal
distribution as described in Appendix H. (Appendix I describes other distributions and models
that EPA might consider for the final regulations.) EPA estimates the percentile for the daily
maximum limitation using the product of the long-term average and the variability factor.
6.6.2. LONG-TERM AVERAGE
In the first of two steps in estimating the different types of limitations, EPA determines an
average performance level (the long-term average) that a site with well-designed and operated
model technologies (which reflect the appropriate level of control) is capable of achieving. This
long-term average is calculated from the data from the sites using the model technology. The
proposed long-term average of 2.77 NTU is the median value of 19 long-term averages collected
from the 19 treatment systems at 17 sites. The long-term averages ranged from a minimum of
0.43 NTU (Site SC05) to a maximum of 21.86 NTU (Site HEO). The median is the midpoint of
the 19 values, and thus, nine of the system-specific averages are above the proposed long-term
average and nine are below, as shown in Table 6-6. EPA expects that all sites subject to the
limitations will design and operate their treatment systems to achieve the long-term average
performance level on a consistent basis because sites with well-designed and operated model
technologies have demonstrated that this can be done.
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Section 6: Limitations and Standards: Data Selection and Calculation
Table 6-6. System-Specific Long-Term Averages Used in Limitation Calculations
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
Median
Long-term average
(NTU)
2.77
1.65
2.54
3.44
3.58
17.93
3.59
1.50
2.07
1.27
3.39
21.86
3.04
0.43
1.25
1.80
0.87
20.94
19.99
2.77
Rank (smallest = 1)
10 (Median)
6
9
13
14
16
15
5
8
4
12
19
11
1
3
7
2
18
17
In its evaluation of the long-term average, EPA also considered a separate data submission with
the average, minimum, and maximum values observed at 17 sites (see Clear Creek Systems, Inc.,
2008 data files Data from Some Sites 2005-06 Season and Chitosan Treatment Results 2005
DCN 43003). Clear Creek Systems provided these summary data (summary data set) in addition
to a data set with individual measurements described in Section 6.4.1.1. From the available
information, EPA was not able to tell if any sites were reported in both data sets. Although some
sites have the same identifiers, the summary statistics (e.g., average) are not the same. The
summary data set identifies the sites by number: 1,2, ..., 11, with what appears to be two sets of
1,2, ..., 6. Because the two sets appear to differ, Table 6-7 distinguishes between them by
assigning different identifiers, A, B, ..., F, to the second set. As shown in Table 6-7, the values
in the summary data set ranged from a minimum of 0.02 NTU (Site 9) to a maximum of 84 NTU
(Site F). The averages reported for each site ranged from 1.5 NTU (Site C) to 12.15 NTU (Site
8). Ten sites had larger average values than the long-term average basis for the limitation.
Because most sites had maximum values indicating extreme discharges, which do not reflect
proper operation of the model technology, EPA expects that the averages without the extreme
discharges would be much closer in value to the long-term average basis for the limitation.
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Section 6: Limitations and Standards: Data Selection and Calculation
Table 6-7. Summary Statistics Used to Evaluate Long-Term Average
Site
1
2
3
4
5
6
7
8
9
10
11
A
B
C
D
E
F
Reported summary statistics
(NTU)
Average
1.9
4.85
1.93
2.49
3.14
4.72
5.45
12.15
2.01
4.5
4.09
2.5
2.8
1.5
4.8
5.4
2.5
Minimum
0.1
0.2
0.04
0.08
0.89
0.1
0.08
0.37
0.02
0.13
0.21
0.2
0.1
0.4
0.4
0.2
0.1
Maximum
26
26.4
26
40
16.9
46.5
56.4
71.6
68
59.5
38.7
37
72.2
51.4
20
41
84
6.6.3. VARIABILITY FACTOR
EPA acknowledges that variability around the long-term average results from normal operations.
This variability means that occasionally sites can discharge at a level that is greater than the
long-term average. This variability also means that sites can occasionally discharge at a level that
is considerably lower than the long-term average. Consequently, in the second step of developing
a limitation, EPA determines an allowance for the variation in pollutant concentrations when
processed through well-designed and operated treatment systems. This allowance for variance
incorporates all components of variability including process and wastewater generation, sample
collection, shipping, storage, and analytical variability. This allowance is incorporated into the
limitations through the use of the variability factors, which are calculated from the data from the
sites using the model technology. The proposed variability factor of 4.58 is the arithmetic
average (or mean) of 19 variability factors collected from the 17 sites also used as the basis of
the proposed long-term average. Table 6-8 provides the 19 system-specific variability factors.
The variability factors ranged from a minimum of 1.96 (Site LSIDE) to a maximum of 10.85
(Site 8), and were calculated as shown in Appendix H.
Page 6-20
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Section 6: Limitations and Standards: Data Selection and Calculation
Table 6-8. System-Specific Variability Factors Used in Limitation Calculations
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
Mean
Daily Variability
Factor (VF^
5.39
4.41
9.09
7.36
6.15
10.85
5.48
4.28
2.43
2.36
2.04
2.08
1.96
1.97
2.66
2.89
3.06
4.54
7.97
4.58
In its evaluation of the proposed daily variability factor, EPA examined TSS limitations
promulgated during the past 10 years, because it has not recently promulgated limitations for
turbidity. Experts generally consider turbidity and TSS to be related and adequately controlled by
many different types of treatment systems. Each regulation used data from well-operated and
controlled treatment processes in determining the variability of TSS. As shown in Table 6-9, the
values for the variability factors are relatively close in value, ranging from 2.9 to 5.4, with an
arithmetic average of 4.1. Because the C&D technology is a relatively simple one, EPA
concluded that the relatively large value of 4.58 for the proposed variability factor still ensures a
level of control that EPA considers possible for a simple technology.
Page 6-21
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Section 6: Limitations and Standards: Data Selection and Calculation
Table 6-9. TSS Variability Factors in Recent Regulations
Category
Centralized Waste
Treatment (USEPA 2000)
Waste Combustors (USEPA
1999b)
Iron and Steel (USEPA
2002)
Landfills (USEPA 1999a)
Pulp, Paper, and
Paperboard, Cluster Rule
(USEPA 1997)
Transportation Equipment
Cleaning (Science
Applications International
Corporation. 2000)
Subcategory
Organics
Oils
Metals
Commercial Hazardous Waste
Combustor
Coke By-Products
Other
1) Hazardous and
2) Non-Hazardous*
bleached papergrade kraft and soda
Barge/Chemical & Petroleum
Food Direct
Option
4
9
3
4
BAT1
DRI BPT
FORGING
1
2
Value
4.8
2.9
3.2
3.6
4.2
4.6
3.5
4.4
4.4
3.11
4.7
5.4
The variability factors for both subcategories were based on the same data.
6.6.4. CALCULATION OF THE PROPOSED LIMITATION
EPA calculated the value of the daily maximum limitation (13 NTU) using the product of the
proposed long-term average (2.77 NTU) and daily variability factor (4.58):
Daily Maximum Limitation =
Long-Term Average x Variability Factor
(2.77 NTU) x (4.58)
13 NTU
EPA rounded the value of the limitation to two significant digits (i.e., 13 NTU). EPA generally
uses a rounding procedure where values of five and above are rounded up and values of four and
below are rounded down. For example, a value of 12.7 would be rounded to 13, while a value of
12.4 would be rounded to 12.
As a consequence of using the long-term average and variability factor as the basis of the
limitation, sites that are designed and operated to achieve long-term average levels should be
capable of compliance with the limitations, which incorporate variability, at all times.
6.6.5. ENGINEERING REVIEW
In conjunction with the statistical methods, EPA performs an engineering review to verify that
the limitations are reasonable based on the design and expected operation of the control
Page 6-22
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Section 6: Limitations and Standards: Data Selection and Calculation
technologies and the site conditions. For the final rule, EPA will perform a more in-depth
examination of the range of performance by the data sets used to calculate the limitations. Data
from some sites demonstrate the best available technology. Data from other sites could
demonstrate the same technology but not the best demonstrated design and operating conditions
for that technology. For these sites, EPA will evaluate the degree to which the site can upgrade
its design, operating, and maintenance conditions to meet the limitations. If such upgrades are
not possible, EPA will modify the limitations to reflect the lowest levels that the technologies
can reasonably be expected to achieve. EPA recognizes that, as a result of the proposed
limitation, some dischargers might need to improve treatment systems, erosion and sediment
controls, and/or treatment system operations to consistently meet the effluent limitation. EPA
determined that this consequence is consistent with the Clean Water Act statutory framework,
which requires that discharge limitations reflect the best available technology.
To evaluate the value of the proposed limitation, EPA compared the value of the proposed
limitation to the daily values used to calculate the limitation. In most instances where the effluent
turbidity was higher than the proposed turbidity limit, the data indicated sudden jumps in
turbidity levels, which suggested that the treatment system was not being operated properly. EPA
evaluated the performance at each system:
Ten of the 19 systems (Sites 3, SC05, SC08, BZR08, BHRBP, BWWTP, ELLRD,
LSIDE, SEAAIR, and STCLLR) had all the daily values less than the proposed
limitation. This is consistent with what is expected from the 99th percentile basis of
the statistical methodology.
Site 2 had 3 of 131 (or two percent) daily values greater than the proposed limitation,
which is consistent with what is expected from the 99th percentile basis of the
statistical methodology. In addition, all three values (15.78, 13.21, and 13.04 NTU)
occurred during the same week in 2004 (11/5/2004, 11/8/2004, and 11/9/2004). Two
of the three are extremely close in value to the proposed limitation. Because the three
values are close in time and at the start of the reported monitoring dates, it is possible
that they reflect start-up conditions rather than normal operating conditions. EPA also
notes that on one of the three days (11/9/2004), the site had the highest effluent
reading of 1936 NTU reported by any site at any time. EPA will reconsider their
inclusion as the basis for the final limitation.
At Site 4, both systems had only one value in 19 (or 5 percent) greater than the
proposed limitation, which also is consistent with what is expected from the 99th
percentile basis of the statistical methodology. However, both large values (23 NTU
and 33.2 NTU) occurred on the same date (2/8/2005) and were an order of magnitude
greater than any other daily value. Because the values substantially differ from the
others, EPA does not consider the values to be representative of normal operations at
the site and will consider their exclusion from final limitation calculations.
Site 6 also had only one value, 32.25 NTU, in 18 (or 6 percent) greater than the
proposed limitation, which is consistent with what is expected from the 99th percentile
basis of the statistical methodology. However, this value also is an order of
magnitude greater than the other daily values and occurred on a holiday (1/1/2005).
Because its value substantially differs from the others, EPA also does not consider
Page 6-23
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Section 6: Limitations and Standards: Data Selection and Calculation
this value to reflect normal operations at the site and will consider its exclusion from
final limitation calculations.
Site 8 had 6 of 18 values greater than the proposed limitation, the majority of which
occurred in the week of 1/11/2005 to 1/15/2005. The values exceeding the proposed
limitation ranged from 14.17 to 38.75 NTU, with the majority of values being greater
than 20 NTU. EPA might exclude the data as the basis of the final limitation because
it does not appear to represent a well-operated and controlled treatment system (see
criterion 3 in Section 6.3). Its turbidity concentrations, on average, are an order of
magnitude greater than most other sites with same treatment system. In addition, it
has a system-specific variability factor (10.85) that is more than twice the value
(4.58) used as the basis of the limitation and is the most variable discharge observed
at any site.
Site 11 had 3 of 42 values greater than the proposed limitation. The three values
(14.06, 15.12, and 23.21 NTU) occurred during the first week of the reported
monitoring. It is possible that the system was experiencing fluctuations due to start-up
operations. The remaining values range from 0.55 to 7.66 NTU. EPA generally does
not consider start-up operations to represent normal operations, and thus, might
exclude the data from final limitation calculations.
All three of the values for Site HEO (25.2, 25, and 13.95 NTU) were greater than the
proposed limitation. For the final rule, EPA will consider whether the data represent a
well-operated system.
At site WLCPO, system 1 had five of nine values and system 2 had four of seven
values greater than the proposed limitation. The values that exceeded the proposed
limitation from system 1 ranged from 19.5 to 36.1 NTU. The values from system 2
ranged from 19.87 to 24.5 NTU. For the final rule, EPA will consider whether the
data represent a well-operated system.
Table 6-10 provides a summary of this comparison. As a result of this comparison for the
proposed limitation and engineering review of the data, EPA concluded that the statistical
distributional assumptions appear to be appropriate for these data.
Page 6-24
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Section 6: Limitations and Standards: Data Selection and Calculation
Table 6-10. Daily Values Greater Than Daily Maximum Limitation
Site/System
2
3
4 SYS1
4 SYS2
6
8
11
BHRBP
BWWTP
BZR08
ELLRD
HEO
LSIDE
SC05
SC08
SEAAIR
STCLLR
WLCPO SYS1
WLCPO SYS2
Total
Number of
daily values
131
21
19
19
18
18
42
23
8
9
19
3
75
6
13
9
17
9
7
466
Daily values greater than daily maximum
limitation of 13 NTU
Number of values
3
0
1
1
1
6
3
0
0
0
0
3
0
0
0
0
0
5
4
27
Percent of total number
2.3%
0.0%
5.3%
5.3%
5.6%
33.3%
7.1%
0.0%
0.0%
0.0%
0.0%
100.0%
0.0%
0.0%
0.0%
0.0%
0.0%
55.6%
57.1%
5.8%
6.6.6. IMPORTANCE OF COMMENTS
Because of the importance of comments to EPA's decisions for the final rule, EPA has provided
its data in the proposed rulemaking record and explained its criteria for reviewing data. Because
its review process could result in changes to the proposed regulation, EPA encourages sites to
provide comments and data even if the operators consider the regulatory requirements in the
proposed rule to be reasonable. It is possible, as a consequence of new data, that EPA would
revise its approach and/or calculate different values for the performance limitations and
standards without additional opportunity for comment. Courts have upheld this practice. In
Marathon Oil v EPA, 564 F.2d 1253, 1272 (9th Cir. 1977), the Court determined that
Petitioners, in case 75-3795, also note that the Administrator's decision ignores
the recommendation of the EPA's Draft Development Document that the standard
be set at 57/85 mg/1. An agency, however, is clearly free to reject an early
conclusion after further study and reflection. All that is important is, as developed
above, that the final permit standards in this case are supported by substantial
Page 6-25
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Section 6: Limitations and Standards: Data Selection and Calculation
evidence. Cf. Console v. FMC, 383 U.S. 607, 620, 86 S.Ct. 1018, 16 L.Ed.2d 131
(1966).
More recently, in American Coke and Coal Chemicals Institute v. Environmental Protection
Agency, 452 F.3d 930, 940 (D.C. Cir. 2006). The Court determined that
Similarly, EPA's decision in the final rule to use the three additional episodes
expanded the scope of the relevant database, but in light of EPA's statement in the
Proposed Development Document that it might reconsider its exclusion of these
other datasets, this possibility was noticed and made available for possible
comment.. .Although the final limitation is more stringent than had been initially
proposed, the limitation is calculated according to the announced procedure and
thus is not "surprisingly distant" from the limitation presaged in the NOPR...
In the data review for the final rule, EPA plans to conduct a thorough review of the data used for
the proposal and any additional data available to it. In evaluating the data to determine if they
should be used as the basis of the final limitation, EPA intends to apply the criteria described in
Section 6.3. As a consequence of applying the criteria, EPA might include or exclude data in a
different manner than the proposal. For example, Table 6-6 indicates that 4 systems (8, HEO,
WLCPO_SYS1, and WLCPO_SYS2) have long-term averages an order of magnitude greater
than the other 15 systems. In addition, Table 6-8 indicates that Site 8 has the most variable
discharges of the 19 systems. By applying its criterion (#3) that the site must demonstrate good
operation of the model treatment technology, EPA might determine that the four sites do not
provide this demonstration, and thus, should be excluded as the basis of the final limitation.
Assuming that EPA makes no other changes (which is unlikely), the final limitation would have
a value of 8.5 NTU instead of the proposed value of 13 NTU. Rather than tacitly agreeing to the
proposed limitation, if an operator agrees that the proposed limitation of 13 NTU is reasonable
but has concerns about meeting a more stringent limitation; the operator might wish to provide
comments and data that support a limitation of 13 NTU.
6.6.7. MONITORING CONSIDERATIONS
Effluent guidelines act as a primary mechanism to control the discharge of pollutants to waters of
the United States. Once finalized, the proposed C&D regulations would be applied to C&D sites
through incorporation in individual National Pollutant Discharge Elimination System (NPDES)
permits or a general permit issued by EPA or authorized states or tribes under section 402 of the
Clean Water Act. In complying with the final rule, the number of measurements required each
day would be determined by the permit authority. While the actual monitoring requirements will
be determined by the permitting authority, in developing the proposed limitation, the Agency has
assumed that sites will report one value for every day that the discharge occurs to be consistent
with permit definitions provided in 40 CFR 122.2 that define the "maximum daily discharge
limitation" as the "highest allowable 'daily discharge.'"
EPA recognizes that some sites regularly monitor multiple times throughout the day to ensure
that the treatment system is operating properly. In addition, because turbidity can be measured
real-time, it is possible to use an automated turbidity meter in conjunction with a data logger to
obtain data during the entire period of discharge. While EPA agrees that such monitoring is
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Section 6: Limitations and Standards: Data Selection and Calculation
appropriate, EPA would, however, discourage the practice of allowing the number of monitoring
samples to vary arbitrarily merely to allow a site to achieve a desired average concentration, i.e.,
a value below the limitation that day. EPA expects that enforcement authorities would prefer, or
even require, monitoring samples at some regular, predetermined frequency. As explained
below, if a site has difficulty complying with the limitation on an ongoing basis, the site should
improve its equipment, operations, and/or maintenance.
In similar situations when it has assumed daily monitoring for other industries, EPA typically has
statistically evaluated the data for possible autocorrelation. When data are said to be positively
autocorrelated, it means that measurements taken at specific time intervals (such as 1 day or 2
days apart) are related. For example, positive autocorrelation would be present in the data if the
final effluent concentration of turbidity was relatively high one day and was likely to remain at
similar high values the next and possibly succeeding days. To evaluate autocorrelation,
generally, the statistical analysis requires at least a 50-day period with measurements from every
day during the period.3 It is sometimes possible to estimate autocorrelation from datasets with
gaps between measurements. Consequently, in developing the final limitations, EPA might
consider whether available statistical strategies for missing data provide reasonable results for
autocorrelation in the C&D effluent datasets. In EPA's experience, autocorrelation generally
tends to have only a slight effect on the estimate of the long-term average and the daily
variability factor, and thus, the maximum daily limitation. (Autocorrelation tends to affect
monthly average limitations more noticeably.)
6.6.8. COMPLIANCE
EPA promulgates limitations that sites are capable of complying with at all times by properly
operating and maintaining their processes and treatment technologies. However, the issue of
exceedances or excursions (values that exceed the limitations) is often raised. Comments often
suggest that EPA include a provision that a facility is in compliance with permit limitations if its
discharge does not exceed the specified limitations, with the exception that the discharge may
exceed the monthly average limitations 1 month out of 20 and the daily average limitations 1 day
out of 100. This issue was, in fact, raised in other rules, including EPA's final Organic
Chemicals, Plastics, and Synthetic Fibers (OCPSF) rulemaking. EPA's general approach in that
case for developing limitations based on percentiles was the same as this rule and was upheld in
Chemical Manufacturers Association v. U.S. Environmental Protection Agency, 870 F.2d 177,
230 (5th Cir. 1989). The Court determined the following:
EPA reasonably concluded that the data points exceeding the 99th and 95th
percentiles represent either quality-control problems or upsets because there can
be no other explanation for these isolated and extremely high discharges. If these
data points result from quality-control problems, the exceedances they represent
are within the control of the plant. If, however, the data points represent
exceedances beyond the control of the industry, the upset defense is available.
3 Box and Jenkins (1976), a classic textbook on time series analyses, states that "It is normally supposed that
successive values of the time series under consideration ... are available for analysis. If possible, at least 50 and
preferably 100 observations should be used." (page 18)
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More recently, this issue was raised in EPA's Phase I rule for the pulp and paper industry. In that
rulemaking, EPA used the same general approach for developing limitations based on percentiles
that it had used for the OCPSF rulemaking and for the proposed CAAP rule. This approach for
the monthly average limitation was upheld in National Wildlife Federation et al. v.
Environmental Protection Agency, 286 F.3d 554, 573 (D.C. Cir. 2002). The Court determined
that:
EPA's approach to developing monthly limitations was reasonable. It established
limitations based on percentiles achieved by facilities using well-operated and
controlled processes and treatment systems. It is therefore reasonable for EPA to
conclude that measurements above the limitations are due to either upset
conditions or deficiencies in process and treatment system maintenance and
operation. EPA has included an affirmative defense that is available to mills that
exceed limitations due to an unforeseen event. EPA reasonably concluded that
other exceedances would be the result of design or operational deficiencies. EPA
rejected Industry Petitioners' claim that facilities are expected to operate
processes and treatment systems so as to violate the limitations at some pre-set
rate. EPA explained that the statistical methodology was used as a framework to
establish the limitations based on percentiles. These limitations were never
intended to have the rigid probabilistic interpretation that Industry Petitioners
have adopted. Therefore, we reject Industry Petitioners' challenge to the effluent
limitations.
As that Court recognized, EPA's allowance for reasonably anticipated variability in its effluent
limitations, coupled with the availability of the upset defense, reasonably accommodates
acceptable excursions. Any further excursion allowances would go beyond the reasonable
accommodation of variability and would jeopardize the effective control of pollutant discharges
on a consistent basis and/or bog down administrative and enforcement proceedings in detailed
fact-finding exercises, contrary to congressional intent. See, for example, Rep. No. 92-414, 92d
Congress, 2d Sess. 64, reprinted in^4 Legislative History of the Water Pollution Control Act
Amendments of 1972 (at 1482); Legislative History of the Clean Water Act of 1977 (at 464-65).
More recently, for EPA's rule for the iron and steel industry, EPA's selection of percentiles was
upheld in American Coke and Coal Chemicals Institute v. Environmental Protection Agency,
452 F.3d 930, 945 (D.C. Cir. 2006). The Court determined that
The court will not second-guess EPA's expertise with regard to what the
maximum effluent limits represent. See Nat'l Wildlife, 286 F.3d at 571-73. As
EPA explains in the Final Development Document, the daily and monthly average
effluent limitations are not promulgated with the expectation that a plant will
operate with an eye toward barely achieving the limitations. Final Development
Document at § 14.6.2. Should a plant do so, it could be expected to exceed these
limits frequently because of the foreseeable variation in treatment effectiveness.
Rather, the effluent limitations are promulgated with the expectation that plants
will be operated with an eye towards achieving the equivalent of the LTA for the
BAT-1 model technology. Id. However, even operated with the goal of achieving
the BAT-1 LTA, a plant's actual results will vary. EPA's maximum daily
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Section 6: Limitations and Standards: Data Selection and Calculation
limitations are designed to be forgiving enough to cover the operations of a well-
operated model facility 99% of the time, while its maximum monthly average
limitations are designed to be forgiving enough to accommodate the operations of
a well-operated model facility 95% of the time. See id. EPA's choice of percentile
distribution represented by its maximum effluent limitation under the CWA
represents an expert policy judgment that is not arbitrary or capricious.
EPA expects that sites will comply with promulgated limitations at all times. If the exceedance is
caused by an upset condition, the site would have an affirmative defense to an enforcement
action if the requirements of 40 CFR 122.41(n) are met. If the exceedance is caused by a design
or operational deficiency, EPA has determined that the site's performance does not represent the
appropriate level of control (best available technology for existing sources; best available
demonstrated technology for new sources). For promulgated limitations and standards, EPA has
determined that such exceedances can be controlled by diligent process and wastewater treatment
system operational practices such as frequent inspection and repair of equipment, use of backup
systems, and operator training and performance evaluations.
6.7. SUMMARY OF STEPS USED TO DERIVE THE PROPOSED LIMITATIONS
This section summarizes the steps used to derive the proposed limitations for turbidity:
Step 1 EPA calculated daily averages from the individual measurements for each treatment
system.
Step 2 EPA calculated the system-specific long-term averages and daily variability factors for
each of the 19 systems that had the model technology.
Step 3 EPA calculated the long-term average of 2.77 NTU as the median of the site long-term
averages. (See Table 6-6.) EPA expects that all sites subject to the limitations will
design and operate their treatment systems to achieve the long-term average
performance level on a consistent basis.
Step 4 EPA calculated the variability factor of 4.58 as the mean of the system-specific
variability factors. (See Table 6-8) If a site operates its treatment system to meet the
relevant long-term average, EPA expects the site to be able to meet the limitations. The
variability factor assures that normal fluctuations in a site's treatment are accounted for
in the limitation. By accounting for these reasonable excursions above the long-term
average, EPA's use of variability factors results in limitations that are generally well
above the actual long-term averages.
Step 5 EPA calculated the daily maximum limitation of 13 NTU using the product of the long-
term average (2.77 NTU) and the daily variability factor (4.58).
Step 6 EPA compared the daily maximum limitations to the site daily values used to develop
the proposed limitations. (See Table 6-10.) EPA usually performs this comparison to
determine whether it used appropriate distributional assumptions for the data used to
develop the limitations. This comparison considers whether the curves EPA used
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Section 6: Limitations and Standards: Data Selection and Calculation
provide a reasonable^ to the actual effluent data or if there was an engineering or
process reason for an unusual discharge. Although the fact that the Agency performs
such an analysis before promulgating limitations might give the impression that EPA
expects occasional exceedances of the limitations, this conclusion is incorrect. EPA
promulgates limitations that facilities are capable of complying with at all times by
properly operating and maintaining their treatment technologies. After performing an
engineering evaluation of the larger values, EPA concluded that the proposed limitation
was reasonable.
6.8. REFERENCES
American Public Health Association, American Water Works Association, and Water
Environment Federation. 1992, 1995, 1998, 2005. Standard Methods for the Examination of
Water and Wastewater. Method 2130B. 18th, 19th, 20th and 21st ed. Washington, DC.
ASCE (American Society of Civil Engineers and AWWA (American Water Works Association).
2005. Water Treatment Plant Design, 4th ed, McGraw-Hill, New York.
ASTM International. 1993. Annual Book ofASTM Standards. Volume 11.01 Water (1), Standard
D1889-94A. ASTM, PA, .
Box, G., and G. Jenkins. 1976. Time Series Analysis forecasting and control. Revised Edition.
Holden-Day, Inc., CA.
Cascade EcoSolutions. 2008. Personal communications transmitting information and files on
February 14, April 27, April 30, May 8, and May 13, 2008. Data sets included Engineering
Report Data and ChitoVan Performance Review Data Set (DCN 43002).
Clear Creek Systems, Inc. 2008. Personal communications transmitting files and other
information. Data files included Data from Some Sites 2005-06 Season and Chitosan
Treatment Results 2005. (DCN 43003)
Gannon, J. 2008a. E-mail to Samantha Lewis, USEPA. April 27, 2008. Performance Data 1.
(DCN 45000).
Gannon, J. 2008b. E-mail to Samantha Lewis, USEPA. April 30, 2008. Performance Data 2.
(DCN 45000).
Gannon, J. 2008c. E-mail to Paul Hanson, Jesse Pritts, et al. May 9, 2008. Performance Data 3.
(DCN 45000).
Gannon, J. 2008d. E-mail to Samantha Lewis, USEPA. May 13, 2008. Performance Data 4
(DCN 45000).
Jurries, D. No date. Flocculation of Construction Site Runoff in Oregon. Oregon Department of
Environmental Quality. DCN 43010.3.
. Accessed October 24,
2008.
Minton, G. 2006. Technical Engineering Evaluation Report (TEER) for the Chitosan-Enhanced
Sand Filtration Technology for Low-Through Operations. Prepared by Minton, Resource
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Planning Associates, for Natural Site Solutions, LLC. (DCN 43002 with supporting data file
at DCN 43002: Engineering Report Data.xls.)
Science Applications International Corporation. 2000. Statistical Support Document for Effluent
Limitations Guidelines and Standards for the Transportation Equipment Cleaning Category.
(DCN 45053).
USEPA (U.S. Environmental Protection Agency). 1993. Methods for the Determination of
Inorganic Substances in Environmental Samples. Method 180.1, Rev. 2.0. EPA/600/R-
93/100. . Accessed November
2008.
USEPA (U.S. Environmental Protection Agency). 1997. Statistical Support Document for the
Pulp and Paper Industry: SubpartB. (DCN 45050)
USEPA (U.S. Environmental Protection Agency). 1999a. Statistical Support Document for
Effluent Limitations Guidelines and Standards for the Landfills Category. EPA-821-B-99-
007. (DCN 45052)
USEPA (U.S. Environmental Protection Agency). 1999b. Statistical Support Document for Final
Effluent Limitations Guidelines and Standards for Commercial Hazardous Waste
Combustors. Volume I, Volume II. EPA 821-B-99-010. (DCN 45051)
USEPA (U.S. Environmental Protection Agency). 2000. Development Document for Effluent
Limitations Guidelines and Standards for the Centralized Waste Treatment Point Source
Category. Volume I, Volume II. EPA 440/1-87/009.
.
USEPA (U.S. Environmental Protection Agency). 2002. Development Document for Effluent
Limitations Guidelines and Standards for the Iron and Steel Manufacturing Point Source
Category. EPA-821 -R-02-004. .
USGS (U.S. Geological Survey). 1989. Methods for the Determination of Inorganic Substances
in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the United
States Geological Survey National Water Quality Laboratory, Eds. Marvin J. Fishman and
Linda C. Friedman. Book 5, Chapter Al. 1-3860-85.
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7. TECHNOLOGY ASSESSMENT
This technology assessment is intended to determine the amount and quality of data available to
describe the performance of currently used site runoff control practices, the ability of each
practice to effectively control impacts due to runoff, and the design criteria or standards currently
used to size each practice to ensure effective control of runoff.
7.1. REVIEW OF HISTORICAL APPROACHES TO EROSION AND SEDIMENT
CONTROL
Most early sediment control was related to agriculture and was installed as a way to maintain our
natural resource base. On-site control was the primary emphasis, attempting to prevent erosion
rather than trap sediment. Strategies were developed to minimize exposure of bare soil to the
erosive power of rainfall and runoff, using aboveground cover management, residue
management, strip cropping, and terracing to limit the length of overland flow. Impacts to
receiving streams and downstream areas had not yet been identified as an issue. In the 1960s
concern began to be expressed about the quantities of sediment in streams and reservoirs, and
sediment was first identified as a pollutant. Initially, the major focus of sediment control was on
the surface mining industry with the passage of the Clean Water Act and then the Surface
Mining, Reclamation, and Control Act (SMRCA) (PL 95-87). The first approach taken to
sediment control was a design standard, requiring a sediment detention basin with a 24-hour
detention time; total suspended solids (TSS) standards of 35 milligrams per liter (mg/L) average
and 70 mg/L peak were also promulgated but were not typically enforced. The U.S.
Environmental Protection Agency (EPA) later evaluated the TSS standard and moved to a
settleable solids standard of 0.5 mL/L, based on a modeling effort that showed that it was not
possible to trap fine sediments, but that a 0.5 mL/L settleable solids standard could be met with a
reasonably sized sediment basin (Ettinger and Lichty 1979).
In the late 1960s and early 1970s, sediment in streams and waterways originating from urban
construction sites became an issue, which was then addressed in the Clean Water Act. EPA
developed a list of best management practices (BMPs) and standards for their construction
(USEPA 1971). In general, these standards were adopted from those of other agencies and were
not based on studies related to urban runoff.
In 1987 the Clean Water Act was amended to include stormwater discharges from urban areas.
The Phase I National Pollutant Discharge Elimination System (NPDES) stormwater regulations
were published in 1990, requiring all municipalities with Municipal Separate Storm Sewer
Systems (MS4) serving populations greater than 100,000, construction sites 5 acres and larger,
and certain industrial sites to obtain a permit. The permit required the development of a
stormwater pollution prevention plan (SWPPP) that typically included a stormwater and
sediment control plan. In 1999 the Phase II NPDES stormwater regulations were published,
extending permit coverage to construction sites of 1 acre or larger and municipalities with
populations greater than 50,000 (or populations greater than 10,000 where population density is
more than 1,000 people per square mile). The regulations allow use of general permits in lieu of
individual site or facility permits. The degree of oversight of construction varies widely among
the states.
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In the past two decades, increased concern at the local level has been focused on sediment
pollution of streams and waterways, particularly originating from construction, while less
concern has been focused on the effects of increased construction on stormwater and chemical
production. Much of this government concern originated from the Phase I and Phase IINPDES
stormwater regulations. A number of states and their local agencies have developed standards
and BMPs for sediment control, most of which do not have a scientific basis but were adopted
from other agencies. Some states, however, did conduct studies that gave their standards some
scientific basis. For example, Maryland evaluated its BMP standards in the 1980s by using
modeling techniques, and the state changed its sediment basin standards to account for the
effects of surface area on the trapping efficiency in sediment ponds. On the basis of typical soils
in the region and modeling studies, the state adopted a surface area to peak discharge ratio of
0.01 cubic feet per second (cfs) per acre as a criterion (Barfield and Clar 1985; McBurnie et al.
1990). Maryland was thus the first state to use a design criterion that was related to the overflow
rate. Other states also used some of Maryland's results (Smolen et al. 1988).
Recent efforts have moved closer to an effluent standard approach. South Carolina conducted a
detailed analysis and published regulations that required a trapping efficiency or settleable solids
standard (SCDHEC 1995). In addition, results from a detailed model were used to develop
simplified design aids (Hayes and Barfield 1995; Holbrook et al. 1998). Some municipalities are
following suit to develop scientifically based standards of their own. For example, in 1998
Louisville, Kentucky (Hayes et al. 2001) developed standards and design aids for stormwater and
sediment control, following the example of South Carolina.
There are no examples in which an integrated approach to stormwater and sediment control has
been used on construction sites. The closest analog is the Cumulative Hydrologic Impact
Analysis (CHIA) required in surface mining by the SMRCA. SMRCA requires each applicant
for a surface mining permit to conduct a hydrologic impact analysis. Subsequently, the
regulatory authority is required to conduct a CHIA for the entire watershed. Note that although a
CHIA is required, it is seldom undertaken on a scale that is useful.
Many of the advances in sediment control have been based on the capability to predict, a priori,
the ability of a given design to meet a standard. For example, when the settleable solids standard
was developed for surface mining, most regulatory authorities adopted it with the requirement
that permit applicants would demonstrate through the use of widely accepted computer models
that the proposed design would meet the settleable solids standard.
Most of the early work in modeling sediment production stemmed from efforts in the 1950s to
develop a soil loss equation that would apply to the entire nation and allow evaluation of
alternative erosion control practices. This led to the relationship known as the Universal Soil
Loss Equation (USLE) (Wischmeier and Smith 1965) and its subsequent derivative, the Revised
USLE (RUSLE) (Renard et al. 1994). These efforts focus on erosion control; thus, the
relationships do not predict sediment yield. A flurry of efforts in the late 1970s and early 1980s
lead to the development of sediment yield relationships such as the Modified USLE (MUSLE)
(Williams, No Date), the CREAMS model (Knisel 1980), SEDCAD (Warner et al. 1999), and
SEDIMOT II (Wilson et al. 1982) and its derivatives. The MUSLE and CREAMS models did
not include methods to evaluate the impact of sediment trapping structures, but SEDIMOT II
contained relationships developed at the University of Kentucky to predict the impact of
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reservoirs (Ward et al. 1977; Wilson and Barfield 1984), check dams (Hirschi 1981), and
vegetative filter strips (Hayes et al. 1984). The MUSLE, SEDCAD and SEDIMOT II models
were based on single storms, while the CREAMS model was based on continuous simulation
modeling. Details on these models can be found in Haan et al. (1994).
More recently, modeling has improved, resulting in several new relationships. The WEPP
watershed model is one example of a continuous simulation approach. It includes computational
procedures for a wide variety of sediment control structures (Lindley et al. 1998). Another
example of a single storm-based model is SEDIMOT III (Barfield et al. 1996), which modifies
the earlier SEDIMOT II model to include channel erosion routines and a wide variety of
sediment control techniques. A significant drawback in the SEDIMOT III and WEPP models is
that they do not have a good technique for predicting the impact of filter fence, which is the most
common technique used today for sediment control. The authors of SEDCAD have attempted to
provide algorithms to represent (silt) filter fence removals, although work remains before global
acceptance in the literature.
Concerns for changes in geomorphology resulting from flow alterations have resulted in several
modeling approaches. Early efforts were focused on what is known as the regime theory, in
which changes in channel property are linked, qualitatively, to changes in flow. Examples
include models of Lane (1955) and Schumm (1977). In addition, some statistically based models
were developed, but they are not universally applicable (Blench 1970; Simons and Albertson
1960). More recently, models have been developed using physically based concepts to predict
changes in geomorphology as related to changes in flow. The models of Chang (1988) are good
examples. It is possible to predict, to a limited extent, the change in channel properties as
affected by changes in flow.
The impact of changes in flow and geomorphology on habitat is one major area in which
information is lacking. Although this deficiency can be addressed qualitatively, it is not possible
to predict quantitatively how a given change in geomorphology will affect habitat. Additional
information is needed to develop a strategy on the basis of the integrated assessment approach.
7.2. CONTROL TECHNIQUES
The following section presents a discussion of the commonly used erosion and sediment control
practices. Information on applicability, design and installation criteria, maintenance
considerations and effectiveness are presented, when available. This section does not discuss
proprietary and vendor-supplied BMPs, many of which are variations of conventional BMPs
such as sediment barriers, filters, and erosion control and prevention practices.
7.2.1. EROSION CONTROL AND PREVENTION
7.2.1.1. Planning, Staging, Scheduling
General Description
A construction sequence schedule is a specified work schedule that coordinates the timing of
land-disturbing activities and the installation of erosion and sediment control measures. The goal
of a construction sequence schedule is to reduce on-site erosion and off-site sedimentation by
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performing land-disturbing activities and installing erosion and sediment control practices in
accordance with a planned schedule (Smolen et al. 1988).
Construction site phasing involves disturbing only part of a site at a time to prevent erosion from
dormant parts (Claytor 1997). Grading activities and construction are completed and soils are
effectively stabilized on one part of the site before grading and construction begin at another
part. This differs from the more traditional practice of construction site sequencing, in which
construction occurs at only one part of the site at the time, but site grading and other site-
disturbing activities typically occur simultaneously, leaving portions of the disturbed site
vulnerable to erosion. Construction site phasing must be incorporated into the overall site plan
early on. Elements to consider when phasing construction activities include the following
(Claytor 1997):
Managing runoff separately in each phase
Determining whether water and sewer connections and extensions can be
accommodated
Determining the fate of already completed downhill phases
Providing separate construction and residential accesses to prevent conflicts between
residents living in completed stages of the site and construction equipment working
on later stages (USEPA 2000)
Applicability
Construction sequencing can be used to plan earthwork and erosion and sediment control
activities at sites where land disturbances might affect water quality in a receiving waterbody.
Design and Installation Criteria
Construction sequencing schedules should, at a minimum, include the following (NCDNR 1988;
MDE 1994):
The erosion and sediment control practices that are to be installed
The principal development activities
The measures that should be installed before other activities are started
The compatibility with the general contract construction schedule Table 7-1
summarizes other important scheduling considerations in addition to those listed
above
Effectiveness
Construction sequencing can be an effective tool for erosion and sediment control because it
ensures that management practices are installed where necessary and when appropriate. A
comparison of sediment loss from a typical development and from a comparable phased project
showed a 42 percent reduction in sediment export in the phased project (Claytor 1997).
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Table 7-1. Scheduling Considerations for Construction Activities
Construction activity
Construction survey stakeout
Pre-construction meeting between
owner, contractor, and regulatory
agency
Construction access entrance to
site, construction routes, areas
designated for equipment parking
Clearing and grading required for
the installation of controls
Sediment traps and barriers
basin traps, silt fences, outlet
protection
Runoff control diversions,
perimeter dikes, water bars, outlet
protection
Runoff conveyance system
stabilize streambanks, storm
drains, channels, inlet and outlet
protection, slope drains
Land clearing and grading site
preparation (cutting, filling, and
grading; sediment traps; barriers;
diversions; drains; surface
roughening)
Surface stabilization temporary
and permanent seeding, mulching,
sodding, riprap
Building construction buildings,
utilities, paving
Landscaping and final
stabilization adding topsoil,
trees, and shrubs; permanent
seeding; mulching; sodding; riprap
Schedule consideration
Before initiating any construction activity a construction survey
stakeout should be conducted. The stakeout should identify the
limits of disturbance and location of control structures, especially
perimeter controls.
This meeting should take place before any construction activity
begins at the site. The survey stakeout is reviewed, especially the
limits of disturbance and location of controls.
This is the first land-disturbing activity. As soon as construction
takes place, any bare areas should be stabilized with gravel and
temporary vegetation.
In conjunction with the construction access, the clearing and
grading required for the installation of erosion and sediment
controls should take place.
After the construction site has been accessed, principal basins
should be installed, with the addition of more traps and barriers as
needed during grading.
Install key practices after the installation of principal sediment
traps and before land grading. Additional runoff control measures
can be installed during grading.
If necessary, stabilize streambanks as soon as possible, and install
the principal runoff conveyance system with runoff control
measures. The remainder of the systems can be installed after
grading.
Implement major clearing and grading after installing principal
sediment and key runoff control measures, and install additional
control measures as grading continues. Clear borrow and disposal
areas as needed and mark trees and buffer areas for preservation.
Immediately apply temporary or permanent stabilizing measures to
any disturbed areas where work has been either completed or
delayed.
During construction, install any erosion and sediment control
measures that are needed.
This is the last construction phase. Stabilize all open areas,
including borrow and spoil areas, and remove and stabilize all
temporary control measures.
Limitations
Weather and other unpredictable variables can affect construction sequence schedules. The
proposed schedule and a protocol for making changes resulting from unforeseen problems should
be plainly stated in an applicable erosion and sediment control plan.
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Maintenance
The construction sequence should be followed throughout the project, and the written erosion
and sediment control plan should be modified before any changes in construction activities are
executed. The plan can be updated if a site inspection indicates the need for additional erosion
and sediment control as determined by contractors, engineers, or developers.
Cost
Construction sequencing is a low-cost BMP because it requires a limited amount of a
contractor's time to provide a written plan for coordinating construction activities and
management practices. Additional time might be needed to update the sequencing plan if the
current plan is not providing sufficient erosion and sediment control.
Although little research has been done to assess the costs of phasing versus conventional
construction costs, it is known that it will be possible to implement successful phasing for a
larger project (Claytor 1997).
7.2.1.2. Vegetative Stabilization
Vegetation can be used during construction to stabilize and protect soil exposed to the erosive
forces of water, as well as post-construction to provide a filtration mechanism for stormwater
pollutants. The following discussion refers to vegetative stabilization as a construction BMP that
stabilizes and protects soil from erosion.
General Description
Vegetative stabilization measures employ plant material to protect soil exposed to the erosive
forces of water and wind. Selected vegetation can reduce erosion by more than 90 percent
(Fifield 1999). Natural plant communities that are adapted to the site provide a self-maintaining
cover that is less expensive than structural alternatives. Plants provide erosion protection to
vulnerable surfaces by the following (Heyer, No Date):
Protecting soil surface from the impact of raindrops
Holding soil particles in place
Maintaining the soil's capacity to absorb water
Using living root systems to hold soil in place, increasing overall bank stability
Directing flow velocity away from the streambank
Acting as a buffer against abrasive transported materials
Causing sediment deposition, which reduces sediment load and reestablishes the
streambank
The designer should be aware of and respond to local conditions that could influence the
development of vegetative stabilization measures. As with any planting design, climate,
maintenance practices, the availability of plant material (including native species), and many
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other factors will influence such considerations as plant or seed mix selection, installation
methods, and project scheduling.
Slope Stabilization. On slopes, the goal of vegetative stabilization is not only to reduce surface
erosion, but also to prevent slope failure. Vegetation should provide dense coverage to protect
soils from the direct impact of precipitation and help intercept runoff. A variety of plants should
be used to provide root systems that are distributed throughout all levels of the soil, increasing
slope shear strength and giving plants a greater ability to remove soil moisture. Uniform mats of
shallow rooting plants should be avoided because, while such plants might increase runoff
infiltration, they cannot remove soil moisture beyond the surface level, leaving slopes potentially
saturated and prone to slippage. Shallow, interlocking root systems could also increase the size
of a soil slippage by holding together and pulling down a larger area of slope after a small
section has given way. Large trees that have become unstable can also pull down slopes and
should be removed. Using plants with low water requirements can reduce the potential for soil
saturation from irrigation.
Swale Stabilization. On swales, the goal of vegetative stabilization is to prevent erosion within
the swale, where runoff is concentrated and flows at higher velocities. If natural stream channels
are involved, vegetation with deep root systems should be preserved, or if absent, planted above
the channel to help maintain the channel banks. More information is provided in the subsequent
section dealing with grass-lined swales.
Surface Stabilization. On large, flat areas, the goal of vegetative stabilization is to reduce the
loss of surface soil from sheet erosion. Vegetation should provide complete coverage to reduce
the force of precipitation, which can shift soil particles to seal openings in the soil, reducing
infiltration and increasing runoff. Vegetation should also provide many stem penetrations to slow
runoff and increase infiltration. Deep rooting plants are less critical for erosion control in flat
areas than on slopes because soils are not subject to the same forces that can cause slippage on a
slope. However, trees and shrubs can increase infiltration, lessening the buildup of runoff, and
transpire large volumes of water, reducing soil saturation.
In areas susceptible to wind erosion, the goal of vegetative stabilization is to establish direct
protection of the soil. Vegetation should provide dense and continuous surface cover. Binding
the soil deeply is generally not a requirement. The ideal vegetation for this purpose is grass,
which forms a mat of protection. In areas where the vegetation is developed, the grass generally
has high maintenance requirements. In less developed, open areas, unmown grass, including
perennial native species, can be used to provide protection. Trees and shrubs also can provide
protection from the wind.
Shoreline Stabilization. In lakes and ponds, the goal of vegetative stabilization is to prevent
erosion of the shoreline. Wetland plants anchor the bottom of the lake or pond adjacent to the
shore and help dissipate the erosive energy of waves. An important consideration in planting
along shorelines is the need to establish favorable conditions for plant establishment and growth.
These include the proper grading of side slopes and the control of upland erosion to prevent the
buildup of silt and associated pollutants in the water. Designers should maintain awareness of
regulatory requirements that might influence vegetation projects in a wetland environment
(USAF 1998).
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Vegetation used for shoreline stabilization work should be native material selected because of
strength, resiliency, vigor, and ability to withstand periodic inundation. Woody vegetation with
short, dense, flexible tops and large root systems works well. Other important factors include
rapid initial growth, ability to reproduce, and resistance to disease and insects.
According to Heyer (No Date), most streambank stabilization plantings have used various
willows, including black willow (Salix nigra), sandbar willow (S. interior), meadow willow (S.
petiolaris), heartleaf willow (S. rigida), and Ward willow (S. caroliniand). The size used
depends on the severity of the erosion and the type of bank to be stabilized.
Most tree revetment projects used either eastern red cedar (Juniperus virginiand) or hardwoods
such as northern pin oak (Quercus ellipsoidalis). Important suggestions include the following:
Choose trees with many limbs and branches to trap as much sediment as possible.
Select decay-resistant trees.
Use recently cut treesdead trees are more brittle and likely to break apart.
The tree size-diameter of the tree crown should be about two-thirds of the height of
the eroding bank.
Cut off any trunk without limbs.
Place the tree revetments overlapping, butt end pointing upstream.
Begin and end revetments at stable points along the bank.
Choose an anchoring system according to the bank material to be stabilized and the
weight of the object to be anchored.
Vegetative measures for streambank stabilization offer an alternative to structural measures and
are becoming well known as bioengineering techniques for streambanks. Using vegetative
material for streambank stabilization could be the first step in the reestablishment of the riparian
forest, which is essential for long-term stability of the streamside and floodplain areas. Each site
must be evaluated separately as to the feasibility of using natural material (Heyer, No Date).
Vegetative streambank stabilization, with the goal of protecting streambanks from the erosive
forces of flowing water, is generally applicable where bankfull flow velocity does not exceed 6
ft/sec and soils are erosion resistant (Smolen 1988). Table 7-2 includes general guidelines for
maximum allowable velocities in streams to be protected by vegetation.
Table 7-2. Conditions Where Vegetative Streambank Stabilization Is Acceptable
Frequency of bankfull
flow
> 4 times/yr
1 to 4 times/yr
< 1 time/yr
Maximum allowable velocity for
highly credible soil
4 ft/sec
5 ft/sec
6 ft/sec
Maximum allowable velocity for
erosion-resistant soil
5 ft/sec
6 ft/sec
6 ft/sec
Source: Smolen 1988
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Temporary Vegetative Stabilization. Temporary vegetative cover such as rapidly growing
annuals and legumes can be used to establish a temporary vegetative cover. Such covers are
recommended for areas that (Fifield 1999)
Will not be brought to final grade within 30 days or are likely to be redisturbed
Require seeding of cut and fill slopes under construction
Require stabilization of soil storage areas and stockpiles
Require stabilization of temporary dikes, dams, and sediment containment systems
Require development of cover or nursery crops to assist with establishing perennial
grasses
Examples of temporary vegetation include wheat, oats, barley, millet, and sudan grass.
Temporary seeding might not be effective in arid or semi-arid regions where seasonal lack of
moisture prevents germination. It might be necessary to use a mixture of warm and cool season
grasses to ensure germination. Mulching and geotextiles can be used to help provide temporary
stabilization with vegetation, particularly in situations where establishing cover could be
difficult.
Permanent Vegetative Stabilization. Permanent vegetative cover such as a perennial grass or a
legume cover can be used to establish a permanent vegetative cover. Permanent vegetation is
recommended for the following (Fifield 1999):
Final graded or cleared areas where permanent vegetative cover is needed to stabilize
the soil
Slopes designated to be treated with erosion control blankets
Grass-lined channels or waterways designed to be protected with channel liners
The following subsections discuss the various types or means of providing vegetative
stabilization
Grass-lined Channels
General Description
Grass-lined channels, or swales, convey stormwater runoff through a stable conduit. Vegetation
lining the channel reduces the flow velocity of concentrated runoff. Grassed channels are usually
not designed to control peak runoff loads by themselves and are often used in combination with
other BMPs such as subsurface drains and riprap stabilization.
Applicability
Grassed channels should be used in areas where erosion-resistant conveyances are needed, such
as in areas with highly erodible soils and slopes of less than 5 percent. They should be installed
only where space is available for a relatively large cross-section. Grassed channels have a limited
ability to control runoff from large storms and should not be used in areas where velocity
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exceeds 5 feet per second unless they are on erosion-resistant soils with dense groundcover at the
soil surface.
Design and Installation Criteria
Because of their ease of construction and low cost, vegetation-lined waterways are frequently
used for diversion and collection ditches. The U.S. Department of Agriculture's (USDA's) Soil
Conservation Service's (SCS) Engineering Field Manual (1979) recommends the maximum
permissible velocities for individual site conditions shown in Table 7-3.
Table 7-3. Maximum Permissible Velocities for Individual Site Conditions for Grass Swales
Site location
Areas where only a sparse cover can be established or
maintained because of shale, soils, or climate
If the vegetation is to be established by seeding
Areas where a dense, vigorous sod is obtained quickly or
where the runoff can diverted out of the waterway while the
vegetation is being established
Velocity
3.00ft/sec(0.91m/sec)
3. 00 to 4. 00 ft/sec (0.91 to
4. 00 to 5. 00 ft/sec (1.22 to
1 .22 m/sec)
1.52 m/sec)
Source: USD A 1979
Grassed waterways typically begin eroding in the invert of the channel if the velocity exceeds the
sheer strength of the vegetation soil interface. Once the erosion process has started, it will
continue until an erosion-resistant layer is encountered. If erosion of a channel bottom is
occurring, rock or stone should be placed in the eroded area or the design should be changed
(UNEP 1994).
Grassed waterways on construction land must be able to carry peak runoff events from snowmelt
and rainstorms (in some areas limited to up to 1 cubic meter of water per second). The size of the
waterway depends on the size of the area to be drained. A typical grassed waterway cross-section
is parabolic with a nearly flat-bottom, a bottom width of 3 m, and channel depth of at least 30
cm. Side slopes usually rise about 1 m for every 10m horizontal distance but could be as steep as
aim rise for every 2 m of horizontal distance. The waterway should follow the natural drainage
path if possible (Vanderwel and Abday 1998). The design should be site-specific and be derived
using well-established procedures.
Lined channels are a means of carrying water to lower elevations along steep parts of a
waterway. Those portions of the waterway are precisely shaped and carefully lined with heavy-
duty erosion control matting (a geotextile product). The lining is covered with a layer of soil and
seeded to grass. The resulting channel is highly resistant to erosion. Lined channels are
appropriate for waterways that only carry water occasionally and have slopes of up to 10 percent.
Companies that sell geotextile products provide detailed information on installation of their
products (Vanderwel and Abday 1998). The design should be site-specific and be derived using
well-established procedures. No standard procedure is available for evaluating the effectiveness
of geotextile liners for pollutant removal.
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Grass-lined channels should be sited in accordance with the natural drainage system and should
not cross ridges. The channel design should not have sharp curves or significant changes in
slope. The channel should not receive direct sedimentation from disturbed areas and should be
sited only on the perimeter of a construction site to convey relatively clean stormwater runoff.
They should be separated from disturbed areas by a vegetated buffer or other BMP to reduce
sediment loads.
Although exact design criteria should be based on local conditions, basic design
recommendations for grassed channels include the following:
Construction and vegetation of the channel should occur before grading and paving
activities begin.
Design velocities should be less than 5 ft/sec.
Geotextiles can be used to stabilize vegetation until it is fully established.
Covering the bare soil with sod or geotextiles can provide reinforced stormwater
conveyance immediately.
Triangular-shaped channels should be used with low velocities and small quantities of
runoff; parabolic grass channels are used for larger flows and where space is
available; trapezoidal channels are used with large flows of low velocity (low
gradient).
Outlet stabilization structures might be needed if the runoff volume or velocity has
the potential to exceed the capacity of the receiving area.
Channels should be designed to convey runoff from a 10-year storm without erosion.
The sides of the channel should be sloped less than 3:1, with V-shaped channels
along roads sloped 6:1 or less for safety.
All trees, bushes, stumps, and other debris should be removed during construction.
Effectiveness
Grass-lined channels can effectively transport stormwater from construction areas if they are
designed for expected flow volumes and velocities and if they do not receive sediment directly
from disturbed areas. The primary function is to carry the flow at a higher velocity without
eroding or overtopping the channel.
Limitations
Grassed channels, if improperly installed, can alter the natural flow of surface water and have
adverse impacts on downstream waters. Additionally, if the design capacity is exceeded by a
large storm event, the vegetation might not be sufficient to prevent erosion and the channel might
be destroyed. Clogging with sediment and debris reduces the effectiveness of grass-lined
channels for stormwater conveyance.
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Maintenance
Maintenance requirements for grass channels are relatively minimal. During the vegetation
establishment period, the channels should be inspected after every rainfall. Other maintenance
activities that should be carried out after vegetation is established are mowing, litter removal, and
spot vegetation replacement. The most important objective in the maintenance of grassed
channels is the maintaining of a dense and vigorous growth of turf. Periodic cleaning of
vegetation and soil buildup in curb cuts is required so that water flow into the channel is
unobstructed. During the growing season, channel grass should be cut no shorter than the level of
design flow, and the cuttings should be removed promptly.
Cost
Costs of grassed channels range according to depth, with a 1.5-foot-deep, 10-foot-wide grassed
channel estimated to cost between $6,395 and $17,075 per trench, while a 3-foot-deep, 21-foot-
wide grassed channel is estimated at $12,909 to $33,404 per trench (SWRPC 1991).
As an alternative cost approximation, grassed channel construction costs can be developed using
unit cost values. Shallow trenching (1 to 4 feet deep) with a backhoe in areas not requiring
dewatering can be performed for $4 to $5 per cubic yard of removed material (R.S. Means
2000). Assuming no disposal costs (i.e., excavated material is placed on either side of the
trench), only the cost of fine grading, soil treatment, and grassing (approximately $2 per square
yard of earth surface area) should be added to the trenching cost to approximate the total
construction cost. Site-specific hydrologic analysis of the construction site is necessary to
estimate the channel conveyance requirement; however, it is not unusual to have flows on the
order of 2 to 4 cfs per acre served. For channel velocities between 1 and 3 feet per second, the
resulting range in the channel cross-section area can be as low as 0.67 square foot per acre
drained to as high as 4 square feet per acre. If the average channel flow depth is 1 foot, the low
estimate for grassed channel installation is $0.27 per square foot of channel bottom per acre
served per foot of channel length. The high estimate is $1.63 per square foot of channel bottom
per acre served per foot of channel length.
Seeding
General Description
Permanent seeding is used to control runoff and erosion on disturbed areas by establishing
perennial vegetative cover from seed. It is used to reduce erosion, decrease sediment yields from
disturbed areas, and provide permanent stabilization. This practice is both economical and
adaptable to different site conditions, and it allows selection of the most appropriate plant
materials. Seeding is a BMP that is particularly susceptible to local conditions such as the
climatic conditions, physical and chemical characteristics of the soil, topography, and time of
year.
Applicability
Permanent seeding is well suited in areas where permanent, long-lived vegetative cover is the
most practical or most effective method of stabilizing the soil. Permanent seeding can be used on
roughly graded areas that will not be regraded for at least a year. Vegetation controls erosion by
protecting bare soil surfaces from displacement by raindrop impacts and by reducing the velocity
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and quantity of overland flow. The advantages of seeding over other means of establishing plants
include lower initial costs and labor inputs.
Design and Installation Criteria
Areas to be stabilized with permanent vegetation must be seeded or planted 1 to 4 months after
the final grade is achieved unless temporary stabilization measures are in place. Successful plant
establishment can be maximized with proper planning; consideration of soil characteristics;
selection of plant materials that are suitable for the site; adequate seedbed preparation, liming,
and fertilization; timely planting; and regular maintenance. Climate, soils, and topography are
major factors that dictate the suitability of plants for a particular site. The soil on a disturbed site
might require amendments to provide sufficient nutrients for seed germination and seedling
growth. The surface soil must be loose enough for water infiltration and root penetration. Soil pH
should be between 6.0 and 6.5 and can be increased with liming if soils are too acidic. Seeds can
be protected with mulch to retain moisture, regulate soil temperatures, and prevent erosion
during seedling establishment.
Seedbed preparation is critical in established vegetation. Spraying seeds on a scraped slope will
generally not provide satisfactory results. Typical seedbed preparation will begin with a soil test
to determine the amount of lime or fertilizer that should be added. In addition, tillage should be
performed that will break up clods so that seed contact can be established. When the seed is
applied, it should be covered and lightly compacted. Natural or synthetic mulch is recommended
to provide surface stabilization until the vegetation is established. In addition to providing
surface stabilization, the mulch will also retard evaporation and encourage rapid growth. A
suitable tack to hold the mulch might be necessary if the mulch is not otherwise anchored. Mulch
as an erosion control practice is covered in a subsequent sub-section.
Depending on the amount of use permanently seeded areas receive, they can be considered high-
or low-maintenance areas. High-maintenance areas are mowed frequently, limed and fertilized
regularly, and either (1) receive intense use (for example, athletic fields) or (2) require
maintenance to an aesthetic standard (for example, home lawns). Grasses used for high-
maintenance areas are long-lived perennials that form a tight sod and are fine-leaved. High-
maintenance vegetative cover is used for homes, industrial parks, schools, churches, and
recreational areas.
Low-maintenance areas are mowed infrequently or not at all and do not receive lime or fertilizer
on a regular basis. Plants must be able to persist with minimal maintenance over long periods of
time. Grass and legume mixtures are favored for these sites because legumes fix nitrogen from
the atmosphere. Sites suitable for low-maintenance vegetation include steep slopes, streambanks
or channel banks, some commercial properties, and utility turf areas such as road banks.
Effectiveness
Seeding that results in a successful stand of grass has been shown to remove between 50 and 100
percent of TSS from stormwater runoff, with an average removal of 90 percent (USEPA 1993).
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Limitations
The effectiveness of permanent seeding can be limited because of the high erosion potential
during establishment, the need to reseed areas that fail to establish, limited seeding times
depending on the season, and the need for stable soil temperature and soil moisture content
during germination and early growth. Permanent seeding does not immediately stabilize soils
temporary erosion and sediment control measures should be in place to prevent off-site transport
of pollutants from disturbed areas. Use of mulches or geotextiles or both could improve the
likelihood of successfully establishing vegetation.
Maintenance
Grasses should emerge within 4 to 28 days and legumes within 5 to 28 days after seeding. A
successful stand should exhibit the following:
Vigorous dark green or bluish green seedlingsnot yellow
Uniform density, with nurse plants, legumes, and grasses well intermixed
Green leavesperennials remaining throughout the summer, at least at the plant
bases
Seeded areas should be inspected for failure, and necessary repairs and reseeding should be made
as soon as possible. If a stand has inadequate cover, the choice of plant materials and quantities
of lime and fertilizer should be reevaluated. Depending on the condition of the stand, areas can
be repaired by overseeding or reseeding after complete seedbed preparation. If the timing is bad,
an annual grass seed can be overseeded to temporarily thicken the stand until a suitable time for
seeding perennials. Consider seeding temporary, annual species if the season is not appropriate
for permanent seeding. If vegetation fails to grow, the soil should be tested to determine whether
low pH or nutrient imbalances are responsible. Local NRCS or county extension agents can also
be contacted for seeding and soil testing recommendations.
On a typical disturbed site, full plant establishment usually requires refertilization in the second
growing season. Soil tests should be used to determine whether more fertilizer needs to be added.
Do not fertilize cool season grasses in late May through July. Grass that looks yellow might be
nitrogen deficient. Nitrogen fertilizer should not be used if the stand contains more than 20
percent legumes.
Cost
Seeding costs range from $200 to $1,000 per acre and average $400 per acre. Maintenance costs
range from 15 to 25 percent of initial costs and average 20 percent (USEPA 1993). R.S. Means
(2000) indicates the cost of mechanical seeding to be approximately $900 per acre and
demonstrates that the coverage cost varies with the seed type, seeding approach and scale (total
acreage to be seeded). For example, hydro or water-based seeding for grass is estimated to be
$700 per acre, but seeding offield grass species is only $540 per acre (Costs include materials,
labor, and equipment, with profit and overhead). If surface preparation is required, the
installation costs increase. R.S. Means suggests the cost of fine grading, soil treatment, and
grassing is approximately $2 per square yard.
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Sodding
General Description
Sodding is a permanent erosion control practice that involves laying a continuous cover of grass
sod on exposed soils. In addition to stabilizing soils, sodding can reduce the velocity of
stormwater runoff. Sodding can provide immediate vegetative cover for critical areas and
stabilize areas that cannot be vegetated by seed. It can also stabilize channels or swales that
convey concentrated flows and reduce flow velocities. While sodding is not as dependent as
seeding on local conditions, it does depend on soil and climatic conditions to be successful.
Watering immediately after installation and occasionally until establishment is generally
beneficial.
Applicability
Sodding is appropriate for any graded or cleared area that might erode, requiring immediate
vegetative cover. Locations particularly well suited to sod stabilization are the following:
Waterways and channels carrying intermittent flow
Areas around drop inlets that require stabilization
Residential or commercial lawns and golf courses where prompt use and aesthetics
are important
Steeply sloped areas
Design and Installation Criteria
Sodding eliminates the need for seeding and mulching and produces more reliable results with
less maintenance. Sod can be laid during times of the year when seeded grasses can fail. The sod
must be watered frequently within the first few weeks of installation. Some seedbed preparation
is recommended, including smoothing to provide contact between the sod and the soil surface
and soil testing to determine liming and fertilizer application rates. Because sod provides
instantaneous cover, mulches are not typically recommended, but anchoring might be
appropriate on steep slopes.
The type of sod selected should be composed of plants adapted to site conditions. Sod
composition should reflect environmental conditions as well as the function of the area where the
sod will be laid. The sod should be of known genetic origin and be free of noxious weeds,
diseases, and insects. The sod should be machine cut at a uniform soil thickness of 15 to 25 mm
at the time of establishment (this does not include top growth or thatch). Soil preparation and
addition of lime and fertilizer could be neededsoils should be tested to determine whether
amendments are needed. Sod should be laid in strips perpendicular to the direction of water flow
and staggered in a brick-like pattern. The corners and middle of each strip should be stapled
firmly. Jute or plastic netting can be pegged over the sod for further protection against washout
during establishment.
Areas to be sodded should be cleared of trash, debris, roots, branches, stones, and clods larger
than 2 inches in diameter. Sod should be harvested, delivered, and installed within a period of 36
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hours. Sod not transplanted within this period should be inspected and approved before its
installation.
Limitations
Compared to seed, sod is more expensive and more difficult to obtain, transport, and store. Care
must be taken to prepare the soil and provide adequate moisture before, during, and after
installation to ensure successful establishment. If sod is laid on poorly prepared soil or unsuitable
surface, the grass will die quickly because it is unable to root. Sod that is not adequately irrigated
after installation can cause root dieback because grass does not root rapidly and is subject to
drying.
Effectiveness
Sod has been shown to remove between 98 and 99 percent of TSS in runoff (USEPA 1993). It is
therefore a highly effective management practice for erosion and sediment control.
Maintenance
Watering is very important to maintain adequate moisture in the root zone and to prevent
dormancy, especially within the first few weeks of installation, until it is fully rooted. Mowing
should not result in the removal of more than one-third of the shoot. Grass height should be
maintained to be 2-3 inches long. After the first growing season, sod might require fertilization
or liming.
Permanent, fine turf areas require yearly fertilization. Warm-season grass should be fertilized in
late spring to early summer, and cool-season grass in late winter and again in early fall.
Cost
Average installation costs of sod average $0.20 per square foot and range from $0.10 to $1.10
per square foot; maintenance costs are approximately 5 percent of installation costs (USEPA
1993). R.S. Means (2000) indicates the sodding ranges between $250 and $750 per 1,000 square
feet for 1-inch deep bluegrass sod on level ground, depending on the size of the area treated (unit
costs value are for orders over 8,000 square feet and less than 1000 square feet, respectively).
Bent grass sod values range between $350 and $500 per 1,000 square feet; again the lower value
is more likely for most construction sites because it is for large area applications. (Costs include
materials, labor, and equipment, with profit and overhead).
Mulching
General Description
Mulching is a temporary erosion control practice in which materials such as grass, hay, wood
chips, wood fibers, straw, or gravel are placed on exposed or recently planted soil surfaces.
Mulching is highly recommended as a stabilization method and is most effective when anchored
in place until vegetation is well established. In addition to stabilizing soils, mulching can reduce
the velocity of stormwater runoff. When used in combination with seeding or planting, mulching
can aid plant growth by holding seeds, fertilizers, and topsoil in place; by preventing birds from
eating seeds; by retaining moisture; and by insulating plant roots against extreme temperatures.
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Mulch mattings are materials such as jute or other wood fibers that are formed into sheets and
are more stable than loose mulch. They can also be easily unrolled during the installation process
and are particularly useful in steeper areas or in channels. Netting can be used to stabilize soils
while plants are growing, although netting does not retain moisture or insulate against extreme
temperatures. Mulch binders consist of asphalt or synthetic materials that are sometimes used
instead of netting to bind loose mulches, but these have been found to have limited usefulness.
Applicability
Mulching is often used in areas where temporary seeding cannot be used because of
environmental constraints. Mulching can provide immediate, effective, and inexpensive erosion
control. On steep slopes and critical areas such as waterways, mulch matting is used with netting
or anchoring to hold it in place. Mulches can be used on seeded and planted areas where slopes
are steeper than 2:1 or where sensitive seedlings require insulation from extreme temperatures.
Design and Installation Criteria
When possible, organic mulches should be used for erosion control and plant material
establishment. Suggested materials include loose straw, netting, wood cellulose, or agricultural
silage. All materials should be free of seed, and loose hay or straw should be anchored by
applying tackifier, stapling netting over the top, or crimping with a mulch crimping tool.
Materials that are heavy enough to stay in place do not need anchoring (for example, gravel).
Steepness of the slope will also affect the extent of anchoring the mulch. Other examples include
hydraulic mulch products with 100 percent post-consumer paper content, yard trimming
composts, and wood mulch from recycled stumps and tree parts. Inorganic mulches such as pea
gravel or crushed granite can be used in unvegetated areas.
Mulches might or might not require a binder, netting, or tacking. All straw and loose materials
must have a binder to hold them in place. Mulch materials that float away during storms can clog
drainage ways and lead to flooding. The extent of binding depends on the type of mulch applied.
Effective use of netting and matting material requires firm, continuous contact between the
materials and the soil. If there is no contact, the material will not hold the soil and erosion will
occur underneath the material. Grading is not necessary before mulching.
There must be adequate coverage, or erosion, washout, and poor plant establishment will result.
If an appropriate tacking agent is not applied or if it is applied in an insufficient amount, mulch
will not withstand wind and runoff. The channel grade and liner must be appropriate for the
amount of runoff or the channel bottom will erode. Also, hydromulch should be applied in
spring, summer, or fall to prevent deterioration of the mulch before plants can become
established. Table 7-4 presents guidelines for installing mulches, but local conditions could
warrant additional requirements.
Effectiveness
Mulching effectiveness varies with the type of mulch used and local conditions such as rainfall
and runoff amounts. Percent soil loss reduction for different mulches ranges from 53 to 99.8
percent and associated water velocity reductions range from 24 to 78 percent (Harding 1990).
Table 7-5 shows soil loss and water velocity reductions for different mulch treatments.
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Table 7-4. Typical Mulching Materials and Application Rates
Material
Rate per
acre
Requirements
Notes
Organic mulches
Straw
Wood fiber or
wood cellulose
Wood chips
Bark
1-2 tons
0.5-1 ton
5-6 tons
35yd3
Dry, unchopped, unweathered;
avoid weeds.
Air dry. Add fertilizer N, 12
Ib/ton.
Air dry, shredded or
hammermilled, or chips.
Spread by hand or machine; must
be tacked or tied down.
Use with hydroseeder; can be
used to tack straw. Do not use in
hot, dry weather.
Apply with blower, chip handler,
or by hand. Not for fine turf
areas.
Apply with mulch blower, chip
handler, or by hand. Do not use
asphalt tack.
Nets and mats
Jute net
Excelsior (wood
fiber) mat
Fiberglass roving
Cover area
Cover area
0.5-1 ton
Heavy, uniform; woven of single
jute yarn. Used with organic
mulch.
Continuous fibers of drawn glass
bound together with a non-toxic
agent.
Withstands water flow.
Apply with compressed air
ejector. Tack with emulsified
asphalt at a rate of 25-35
gal/1,000 ft2 .
Table 7-5. Measured Reductions in Soil Loss for Different Mulch Treatments
Mulch characteristics
100% wheat straw/top net
100% wheat straw/two nets
70% wheat straw/30% coconut fiber
70% wheat straw/30% coconut fiber
100% coconut fiber
Nylon monofilament/two nets
Nylon monofilament/rigid/bonded
Vinyl monofilament/flexible/bonded
Curled wood fibers/top net
Curled wood fibers/two nets
Antiwash netting (jute)
Interwoven paper and thread
Uncrimped wheat straw-2,242 kg/ha
Uncrimped wheat straw-4,484 kg/ha
Soil loss reduction
(%)
97.5%
98.6%
98.7%
99.5%
98.4%
99.8%
53.0%
89.6%
90.4%
93.5%
91.8%
93.0%
84.0%
89.3%
Water velocity reduction (%)
relative to bare soil
73%
56%
71%
78%
77%
74%
24%
32%
47%
59%
59%
53%
45%
59%
Source: Harding 1990, as cited in USEPA 1993
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Limitations
Mulching, matting, and netting might delay seed germination because the cover changes soil
surface temperatures. The mulches themselves are subject to erosion and could be washed away
in a large storm if not sufficiently anchored with netting or tacking. Maintenance is necessary to
ensure that mulches provide effective erosion control.
Maintenance
Mulches must be anchored to resist wind displacement. Netting should be removed when
protection is no longer needed and disposed of in a landfill or composted. Mulched areas should
be inspected frequently to identify areas where mulch has loosened or been removed, especially
after rain storms. Such areas should be reseeded (if necessary) and the mulch cover replaced
immediately. Mulch binders should be applied at rates recommended by the manufacturer. If
washout, breakage, or erosion occurs, surfaces should be repaired, reseeded, and remulched, and
new netting should be installed. Inspections should be continued until vegetation is firmly
established.
Cost
The costs of seed and mulch average $1,500 per acre and range from $800 to $3,500 per acre
(USEPA 1993). R.S. Means (2000) estimates the cost of power mulching to be $22.50 per 1,000
square feet, for large volume applications. In addition, hydro- and mechanical seeding are
approximately $700 to $900 per acre. Coverage cost varies with the seed type, seeding approach,
and scale (total acreage to be seeded). For example, hydro or water-based seeding for grass is
estimated to cost $700 per acre, but seeding offield grass species is only $540 per acre. (Costs
include materials, labor, and equipment, with profit and overhead.) If surface preparation is
required, the installation costs increase. R.S. Means (2000) suggests the cost of fine grading, soil
treatment, and grassing is approximately $2 per square yard of earth surface area.
Vegetated Buffer Strips
General Description
Vegetated buffers are areas of either natural or established vegetation that are maintained to
protect the water quality of neighboring areas. Buffer zones reduce the velocity of stormwater
runoff, provide an area for the runoff to permeate the soil, allow ground water recharge, and act
as filters to catch sediment. The reduction in velocity also helps to prevent soil erosion.
Applicability
Vegetated buffers can be used in any area that is able to support vegetation, but they are most
effective and beneficial on floodplains, near wetlands, along streambanks, and on steep, unstable
slopes. They are also effective in separating land use areas that are not compatible and in
protecting wetlands or waterbodies by displacing activities that could be sources of nonpoint
source pollution.
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Design and Installation Criteria
To establish an effective vegetative buffer, the following guidelines should be followed:
Soils should not be compacted.
Slopes should be less than 5 percent.
Buffer widths should be determined after careful consideration of slope, vegetation,
soils, depth to impermeable layers, runoff sediment characteristics, type and quantity
of storm water pollutants, and annual rainfall.
Buffer widths should increase as slope increases.
Zones of vegetation (native vegetation in particular), including grasses, deciduous and
evergreen shrubs, and understory and overstory trees, should be intermixed.
In areas where flows are concentrated and velocities are high, buffer zones should be
combined with other structural or nonstructural BMPs as a pretreatment.
Vegetated strips have been studied extensively, with emphasis placed on their effectiveness in
removing sediment and other pollutants. Vegetated strips are most appropriate at sites where
sediment loads are relatively low, because high sediment loads will cause large quantities of
deposition along the leading edge of the vegetation. This deposition will cause the flow to divert
around the vegetation in a concentrated flow pattern, which will cause short-circuiting and
greatly reduce removal efficiency. Variability in vegetation density and uniformity often causes
similar problems. Removal efficiency depends on a combination of slope, length, and width of
the filter; density of the vegetation; sediment characteristics, hydraulics of the flow; and
infiltration. The interaction of these variables is complex and prevents the process from being
reduced to a simple relationship except on a local basis. For site-specific local conditions,
methods have been developed that allow trapping to be related to strip length and slope.
Effectiveness
Considerable data have been collected on the effectiveness of buffer strips for specific
conditions. Numerous factors such as infiltration rate, flow depth, slope, dimensions of the
buffer, density and type of vegetation, sediment size, and sediment density impact removal rates.
Recent studies show that even short vegetative buffers can trap high percentages of sediment and
certain chemicals. A significant concern is whether flow is allowed to concentrate, which will
greatly reduce the travel time through the buffer and prevent the removal of pollutants.
Several researchers have measured greater than 90 percent reductions in sediment and nitrate
concentrations; buffer/filter strips do a reasonably good job of removing phosphorus attached to
sediment, but are relatively ineffective in removing dissolved phosphorus (Gillman 1994).
However, because the hydraulics of flow through buffer strips are not well defined and can vary
considerably by site conditions, it is difficult to consistently estimate the effectiveness of buffer
strips.
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Limitations
Vegetated buffers require plant growth before they can be effective, and land must be available
on which to plant the vegetation. If land costs are very high, buffer zones might not be cost-
effective. Although vegetated buffers help to protect water quality, they usually do not
effectively mitigate concentrated stormwater flows to neighboring or downstream wetlands.
Maintenance
Keeping the vegetation in vegetated buffers healthy requires routine maintenance, which
(depending on species, soil types, and climatic conditions) can include weed and pest control,
mowing, fertilizing, liming, irrigating, and pruning. Inspection and maintenance are most
important when buffer areas are first installed. Once established, vegetated buffers do not require
much maintenance beyond the routine procedures listed earlier and periodic inspections of the
areas, especially after any heavy rainfall and at least once a year. Inspections should focus on
encroachment, gully erosion, density of vegetation, evidence of concentrated flows through the
areas, and any damage from foot or vehicular traffic. If there are more than 6 inches of sediment
in one place, it should be removed.
Cost
Conceptual cost estimates for grassed buffer strips can be made on the basis of square footage
using unit cost values. R.S. Means (2000) estimates the cost of fine grading, soil treatment, and
grassing to be $2 per square yard. This cost estimate is based on application of traditional lawn
seed. The cost for field seed is lower than lawn seed, reducing the coverage price. Where gently
sloping areas just need to be grassed with acceptable species, the cost can be as low as $0.38 per
square yard.
7.2.1.3. Non-Vegetative Stabilization
Non-vegetative practices can also be used during construction to stabilize and protect soil
exposed to the erosive forces of water, as well as post-construction to provide a filtration
mechanism for stormwater pollutants. Non-vegetative stabilization techniques operate on the
same principles as vegetative stabilization, however these practices use a variety of synthetic on
natural materials (such as coconut fiber) to stabilize exposed soils. Non-vegetative practices are
particularly useful as temporary stabilization measures until vegetative practices have had a
chance to become established. The following discussion refers to non-vegetative stabilization as
a construction BMP that stabilizes and protects soil from erosion. There are a variety of
proprietary and vendor-supplied materials in this category, which are not discussed in detail.
Geotextiles
General Description
Geotextiles are porous fabrics also known as filter fabrics, road rugs, synthetic fabrics,
construction fabrics, or simply fabrics. Geotextiles are manufactured by weaving or bonding
fibers made from synthetic materials such as polypropylene, polyester, polyethylene, nylon,
polyvinyl chloride, glass, and various mixtures of these materials. As a synthetic construction
material, geotextiles are used for a variety of purposes such as separators, reinforcement,
filtration and drainage, and erosion control (USEPA 1992). Some geotextiles are made of
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biodegradable materials such as mulch matting and netting. Mulch mattings are jute or other
wood fibers that have been formed into sheets and are more stable than normal mulch. Netting is
typically made from jute, wood fiber, plastic, paper, or cotton and can be used to hold the
mulching and matting to the ground. Netting can also be used alone to stabilize soils while the
plants are growing; however, it does not retain moisture or temperature well.
Geotextiles can aid in plant growth by holding seeds, fertilizers, and topsoil in place. Fabrics are
relatively inexpensive for certain applicationsa wide variety of geotextiles exist to match the
specific needs of the site.
Applicability
Geotextiles can be used for erosion control by using it alone. Geotextiles can be used as matting,
which is used to stabilize the flow of channels or swales or to protect seedlings on recently
planted slopes until they become established. Matting can be used on tidal or streambanks where
moving water is likely to wash out new plantings. They can also be used to protect exposed soils
immediately and temporarily, such as when active piles of soil are left overnight.
Geotextiles are also used as separators. An example of such a use is geotextile as a separator
between riprap and soil. This sandwiching prevents the soil from being eroded from beneath the
riprap and maintaining the riprap's base.
Design and Installation Criteria
Many types of geotextiles are available. Therefore, the selected fabric should match its purpose.
State or local requirements, design procedures, and any other applicable requirements should be
considered. In the field, important concerns include regular inspections to determine whether
cracks, tears, or breaches are present in the fabric and to identify when repairs should be made.
Effective netting and matting require firm, continuous contact between the materials and the soil.
If there is no contact, the material will not hold the soil and erosion will occur underneath the
material.
Effectiveness
A geotextile's effectiveness depends on the strength of the fabric and proper installation. For
example, when protecting a cut slope with a geotextile, it is important to properly anchor the
fabric using appropriate length and spacing of wire staples. This will ensure that it will not be
undermined by a storm event.
Limitations
Geotextiles (primarily synthetic types) have the potential disadvantage of being sensitive to light
and must be protected before installation. Some geotextiles might promote increased runoff and
can blow away if not firmly anchored. Depending on the type of material used, geotextiles might
need to be disposed of in a landfill, making them less desirable than vegetative stabilization. If
the fabric is not properly selected, designed, or installed, the effectiveness can be reduced
drastically.
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Maintenance
Regular inspections should be made to determine whether cracks, tears, or breaches have formed
in the fabricit should be repaired or replaced immediately. It is necessary to maintain contact
between the ground and the geotextile at all times.
Cost
Costs for geotextiles range from $0.50 to $10.00 per square yard depending on the type chosen
(SWRPC 1991). Geosynthetic turf reinforcement mattings (TRMs) are widely used for
immediate erosion protection and long-term vegetative reinforcement, usually for steeply sloped
areas or areas exposed to runoff flows. The Erosion Control Technology Council (a geotextile
industry support association) estimates TRMs cost approximately $7.00 per square yard
(installed) for channel protection (Lancaster et al. 2002). Channel protection is one of the most
demanding of installations (much more demanding than general coverage of denuded area).
Honningford (2002) estimated the cost to install a simple soil blanket (or rolled erosion control
product), seed, and fertilizer to be $1.00 per square yard.
Erosion Control Matting
General Description
Erosion control mats can be either organic or made from a synthetic material. A wide variety of
products exist to match the specific needs of the site. Organic mats are made from such materials
as wood fiber, jute net, and coconut coir fiber. Unlike organic matter, synthetic mats are
constructed from non-biodegradable materials and remain in place for many years. These organic
mats are classified as TRMs and Erosion Control and Revegetation Mats (ECRMs) (USDOT
1995).
Erosion control matting aids in plant growth by holding seeds, fertilizers, and topsoil in place.
Matting can be used to stabilize the flow of channels or swales or to protect seedlings on recently
planted slopes until they become established. Matting can be used on tidal or streambanks where
moving water is likely to wash out new plantings. It can also be used to protect exposed soils
immediately and temporarily, such as when active piles of soil are left overnight.
Applicability
Mulch mattings, netting, and filter fabrics are particularly useful in steep areas and drainage
swales where loose seed is vulnerable to being washed away or failing to survive dry soil (UNEP
1994). Erosion control mats can also be used to separate riprap and soil. This results in a
sandwiching effect, maintaining the riprap's base and preventing the soil beneath from being
eroded.
Design and Installation Criteria
Matting is especially recommended for steep slopes and channels (UNEP 1994). Many types of
erosion control mats are available. Therefore, the selected product should match its purpose.
Effective netting and matting require firm, continuous contact between the materials and the soil.
If there is no contact, the material will not hold the soil, and erosion will occur underneath the
material.
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Wood fiber or curled wood mat consists of curled wood with fibers, 80 percent of which are 150
mm or longer, with a consistent thickness and even distribution of fiber over the entire mat. The
top side of the mat is covered with a biodegradable plastic mesh. The mat is placed in the
channel or on the slope parallel to the direction of flow and secured with staples and check slots.
This is applied immediately after seeding operations (USDOT 1995).
Jute net consists of jute yarn, approximately 5 mm in diameter, woven into a net with openings
that are approximately 10 by 20 mm (or 0.40 to 0.79 inches). The jute net is loosely laid in the
channel parallel to the direction of flow. The net is secured with staples and check slots at
intervals along the channel. Placement of the jute net is done immediately after seeding
operations (USDOT 1995).
Coconut blankets are constructed of biodegradable coconut fibers that resist decay for 5 to 10
years to provide long, temporary erosion control protection. The materials are often encased in
ultraviolet stabilized nets and sometimes have a composite, polypropylene structure to provide
permanent turf reinforcement. These materials are best used for waterway stabilization and
slopes that require longer periods to stabilize (USDOT 1995).
Within the synthetic mat category are TRMs and ECRMs. TRMs are three-dimensional polymer
nettings or monofilaments formed into a mat. They have sufficient thickness (> 13 mm or 0.5
inch) and void space (> 90 percent) to allow for soil filling and retention. The mat acts as a
traditional mat to protect the seed and increase germination. As the turf establishes, the mat
remains in place as part of the root structure. This gives the established turf a higher strength and
resistance to erosion (USDOT 1995).
ECRMs are composed of continuous monofilaments bound by heat fusion or stitched between
nettings. They are thinner than TRMs and do not have the void space to allow for filling of soil.
They act as permanent mulch and allow vegetation to grow through the mat (USDOT 1995).
Effectiveness
The effectiveness of erosion control matting depends on the strength of the material and proper
installation. For example, when protecting a cut slope with an erosion control mat, it is important
to anchor the mat properly. This will ensure that it will not be undermined by a storm event.
While erosion control blankets can be effective, their performance varies. Some general trends
are that organic materials tend to be the most effective (Harding 1990) and that thicker materials
are typically superior (Fifield 1999), but there are exceptions to both of these trends. Information
about product testing of blankets is generally lacking. One notable exception is the Texas
Department of Transportation, which publishes the findings of their testing program in the form
of a list of acceptable and unacceptable materials for specific uses.
Limitations
Erosion control mats (primarily synthetic types) are sensitive to light and for this reason must be
protected before installation. Some erosion control mats might cause an increase in runoff or
blow away if not firmly anchored. Erosion control mats might need to be properly disposed of in
a landfill, depending on the type of material. Effectiveness could be reduced if the fabric is not
properly selected, designed, or installed.
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Maintenance
Regular inspections are necessary to determine whether cracks, tears or breaches have formed in
the fabric. Contact between the ground and erosion control mat should be maintained at all times
and trapped sediment removed after each storm event.
Cost
Costs for erosion control mats range from $0.50 to $10.00 per square yard depending on the type
chosen (SWRPC 1991). Geosynthetic TRMs are widely used for immediate erosion protection
and long-term vegetative reinforcement, usually for steeply sloped areas or areas exposed to
runoff flows. The Erosion Control Technology Council (a geotextile industry support
association) estimates that TRMs cost approximately $7.00 per square yard (installed) for
channel protection (ECTC 2002a). Channel protection is one of the most demanding of
installations (much more demanding than general coverage of denuded area). The ECTC
estimates the cost to install a simple soil blanket (or rolled erosion control product), seed, and
fertilizer to be $1.00 per square yard (ECTC 2002b).
Topsoiling
General Description
Topsoiling is the placement of a surface layer of soil enriched in organic matter over a prepared
subsoil to provide a suitable soil medium for vegetative growth on areas with poor moisture, low
nutrient levels, undesirable pH, and/or the presence of other materials that would inhibit the
establishment of vegetation. Advantages of topsoil include its high organic matter content and
friable consistency and its water-holding capacity and nutrient content. The texture and friability
of topsoil are usually more conducive to seedling emergence and root growth. In addition to
being a better growth medium, topsoil is often less erodible than subsoils, and the coarser texture
of topsoil increases infiltration capacity and reduces runoff. During construction, topsoil is often
removed from the project area and stockpiled. It is replaced on areas to be grassed or landscaped
during the final stages of the project.
Applicability
Conditions where topsoiling applies include the following:
Where a sufficient supply of quality topsoil is available
Where the subsoil or areas of existing surface soil present the following problems:
o The structure, pH, or nutrient balance of the available soil cannot be amended by
reasonable means to provide an adequate growth medium for the desired
vegetation
o The soil is too shallow to provide adequate rooting depth or will not supply
necessary moisture and nutrients for growth of desired vegetation
o The soil contains substances toxic to the desired vegetation
Where high quality turf or ornamental plants are desired
Where slopes are 2:1 or flatter
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Design and Installation Criteria
The topsoil should be uniformly distributed over the subsoil to a minimum compacted depth of
50 mm (2 inches) on slopes steeper than 3:1 and 100 mm (4 inches) on flatter slopes.
Thicknesses of 100 to 150 mm are preferred for vegetation establishment via seeding. The
topsoil should not be placed while in a frozen or muddy condition or when the subsoil is
excessively wet, frozen, or in a condition that is detrimental to proper grading or seedbed
preparation. The final surface should be prepared so that any irregularities are corrected and
depressions and water pockets do not form. If the topsoil has been treated with soil sterilants, it
should not be placed until the toxic substances have dissipated (USDOT 1995). Table 7-6
summarizes the cubic yards of topsoil required for application to various depths.
Table 7-6. Cubic Yards of Topsoil Required for
Application to Various Depths
Depth
(inches)
1
2
3
4
5
6
Per 1,000 Sq Ft
3.1
6.2
9.3
12.4
15.5
18.6
Per acre
134
268
403
536
670
804
Source: Smolenetal. 1988.
On slopes and areas that will not be mowed, the surface could be left rough after spreading
topsoil. A disk can be used to promote bonding at the interface between the topsoil and subsoil
(Smolenetal. 1988).
Effectiveness
No information is available describing the effectiveness of applying topsoil as a BMP.
Limitations
Limitations of applying topsoil can include the following:
Topsoil spread when conditions are too wet, resulting in severe compaction
Topsoil mixed with too much unsuitable subsoil material, resulting in poor vegetation
establishment
Topsoil contaminated with soil sterilants or chemicals, resulting in poor or no
vegetation establishment
Topsoil not adequately incorporated or bonded with the subsoil, resulting in poor
vegetation establishment and soil slippage on sloping areas
Topsoiled areas not protected, resulting in excessive erosion
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Maintenance
Newly topsoiled areas should be inspected frequently until the vegetation is established. Eroded
or damaged areas should be repaired and revegetated.
Cost
Topsoiling costs are a function of the price of topsoil, the hauling distance, and the method of
application. R.S. Means (2000) reports unit cost values of $3 and $4 per square yard, for 4 and 6
inches of topsoil cover, respectively. This price is for furnishing and placing of topsoil, and
includes materials, labor, and equipment, with profit and overhead.
7.2.2. WATER HANDLING PRACTICES
7.2.2.1. Earth Dike
General Description
An earth dike is a temporary or permanent ridge of soil designed to channel water to a desired
location. Dikes are used to divert the flow of runoff by constructing a ridge of soil that intercepts
and directs the runoff to the desired outlet or alternative management practice, such as a pond.
This practice serves to reduce the length of a slope for erosion control and protect downslope
areas. An earth dike can be used to prevent runoff from going over the top of a cut and eroding
the slope, directing runoff away from a construction site or building; to divert clean water from a
disturbed area; or to reduce a large drainage area into a more manageable size. Dikes should be
stabilized with vegetation after construction (NAHB, No Date).
Applicability
Earth dikes are applicable to all areas; the size of the dike is correlated to the size of the drainage
area (NAHB, No Date).
Design and Installation Criteria
The location of dikes should take into consideration outlet conditions, existing land use,
topography, length of slope, soils, and development plans. The capacity of earth dikes and
diversions should be suitable for the area that is being protected, including adequate freeboard, or
extra depth that is added as a safety margin. For homes, schools, and industrial buildings, the
recommended design frequency storm is 50 years and the freeboard is 0.5 feet (NAHB, No
Date).
Earth dikes can be employed as a perimeter control. For small sites, a compacted 2-foot-tall dike
is usually suitable, if hydroseeded. Larger dikes will actually divert runoff to another portion of
the site, usually to a downstream sediment trap or basin. Therefore, the designer should ensure
that they have the capacity for the 10-year storm event and that the channel created behind the
dike is properly stabilized to prevent erosion (Brown and Schueler 1997). In addition, the
downstream structure must be sized to handle the flow from the dike. Dikes should be designed
using standard hydrologic and hydraulic calculations and certified by a professional hydrologist
or engineer. Diversion dikes should be installed before the majority of the soil-disturbing
activity. As soon as the dike form is completed, it should be machine compacted, fertilized, and
either seeded and mulched or sodded. Excavated materials should be properly stockpiled for
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future use or disposed of properly. Dikes should have an outlet that functions with a minimum of
erosion. Depending on site conditions and outlet structures, the runoff directed by dikes might
need to be conveyed to a sediment-trapping device, such as a sediment basin or detention pond.
As grades increase over 4 percent, geotextile material or sod could be required to control erosion.
Slopes greater than 8 percent could require riprap. Dikes can be removed when stabilization of
the drainage area and outlet are complete (NAHB, No Date). Dike design criteria must
incorporate site-specific conditions, as dimensions depend on expected flows, soil types, and
climatic conditions. All of these inputs vary tremendously over different sections of the country.
Effectiveness
No information has been found on the effectiveness of earth dikes used as BMPs, although
terraces often have sediment removal rates of up to 90 percent.
Limitations
An erosion-resistant lining in the channel might be needed to prevent erosion in the channel
caused by excessive grade. In addition, the channel should be deepened and the grade realigned
if there is overtopping caused by sediment in the channel where the grade decreases or reverses.
If overtopping occurs at low points in the ridge where the diversion crosses the shallow draw, the
ridge should be reconstructed with a positive grade toward the outlet at all points. Finally, if
there is erosion at the outlet, an outlet stabilization structure should be installed; if sedimentation
occurs at the diversion outlet, a temporary sediment trap should be installed.
Maintenance
An earth dike should be inspected for signs of erosion after every major rain event. Any repairs
and/or revegetation should be completed promptly (NAHB, No Date). The following actions can
be taken to properly maintain an earth dike:
Remove debris and sediment from the channel immediately after the storm event.
Repair the dike to its original height.
Check outlets and make necessary repairs to prevent gully formation.
Clean out sediment traps when they are 50 percent full.
Once the work area has been stabilized, remove the diversion ridge, fill and compact
the channel to blend with the surrounding area, and remove sediment traps, disposing
of unstable sediment in a designated area.
Cost
The cost of an earth dike depends on the design and materials used. Small dikes can cost
approximately $2.00 per linear foot, while larger dikes can cost approximately $2.00 per cubic
yard. Earth dikes can cost approximately $4.50 per linear foot (NAHB, No Date).
An alternative means to estimate conceptual costs for earthen dikes is to use unit cost values and
a rough estimate of the quantities needed. Shallow trenching (1 to 4 feet deep) with a backhoe in
areas not requiring dewatering can be performed for $4 to $5 per cubic yard of removed material
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(R.S. Means 2000). On the basis of this value, $2 per linear foot provides for 11 square feet of
flow area and $4.50 per linear foot provides for 24 square feet of flow area. This suggests that
the size of the dike is required before specifying a cost, which requires a site-specific hydrologic
evaluation. On the basis of standards for Virginia, most small drainage areas (made up of 5 acres
or less) require 18-inch tall diversion dikes with a 4.5-foot base. Assuming the excavation
volume equals the volume of the dike, the resulting excavation volume is approximately 7 cubic
feet per linear foot, which (conservatively) equates to $1.03 to $1.30 per linear foot for
construction costs.
If the earthen dikes are to be permanent, additional costs are incurred to vegetate the dike. R.S.
Means (2000) estimates the cost of fine grading, soil treatment, and grassing is approximately $2
per square yard of earth surface area. This adds approximately $6 per linear foot of dike. Where
gently sloping areas just need to be grassed with acceptable species, the cost can be as low as
$0.38 per square yard.
7.2.2.2. Temporary Swale
General Description
The term swale (grassed channel, dry swale, wet swale, biofilter) refers to a series of vegetated,
open channel management practices designed specifically to treat and attenuate stormwater
runoff for a specified water quality volume. As stormwater runoff flows through these channels,
it is treated by filtering through the vegetation in the channel, filtering through a subsoil matrix,
and/or infiltrating into the underlying soils. Variations of the grassed swale include the grassed
channel, dry swale, and wet swale. The specific design features and methods of treatment differ
in each of these designs, but all are improvements on the traditional drainage ditch and
incorporate modified geometry and other features for use of the swale as a treatment and
conveyance practice.
Applicability
Grassed swales can be applied in most situations with some restrictions and are very well suited
for treating highway or residential road runoff because they are linear practices. Perimeter
dikes/swales should be limited to a drainage area of no more than 0.8 hectare and usually work
best on gently sloping terrain. Perimeter dikes might not work well on moderate slopes, and they
should never be established on slopes exceeding 20 percent (UNEP 1994).
Regional Applicability. Grassed swales can be applied in most regions of the country. In arid
and semi-arid climates, however, the value of these practices needs to be weighed against the
water needed to irrigate them.
Ultra-Urban Areas. Ultra-urban areas are densely developed urban areas in which little
pervious surface exists. Grassed swales are generally not well suited to ultra-urban areas because
they require a relatively large area of pervious surface.
Stormwater Hot Spots. Stormwater hot spots are areas where land use or activities generate
highly contaminated runoff, with concentrations of pollutants in excess of those commonly
found in stormwater. A typical example is a gas station or convenience store. With the exception
of the dry swale design, hot spot runoff should not be directed toward grassed channels. These
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practices either infiltrate stormwater or intersect the ground water, making use of the practices
for hot spot runoff a threat to ground water quality.
Stormwater Retrofit. A stormwater retrofit is a stormwater management practice (usually
structural), put into place after development has occurred, to improve water quality, protect
downstream channels, reduce flooding, or meet other specific objectives. One retrofit
opportunity using grassed swales modifies existing drainage ditches. Ditches have traditionally
been designed to convey stormwater away from roads as quickly as possible. In some cases, it
might be possible to incorporate features to enhance pollutant removal or infiltration such as
check dams (for example, small dams along the ditch that trap sediment, slow runoff, and reduce
the longitudinal slope). Because grassed swales cannot treat a large area, using this practice to
retrofit an entire watershed would be expensive because of the number of practices needed to
manage runoff from a significant amount of the watershed's land area.
Cold Water (Trout) Streams. Grassed channels are a good treatment option in watersheds that
drain to cold water streams. These practices do not retain water for a long period of time and
often induce infiltration. As a result, standing water will not typically be subjected to warming
by the sun in these practices.
Design and Installation Criteria
Temporary swales should be designed using standard hydrologic and hydraulic calculations.
Designs should be certified by a professional hydrologist, engineer, or other appropriate
professional.
Perimeter dikes/swales should be established before any major soil-disturbing activity takes
place. Dikes should be compacted with construction equipment to the design height plus 10
percent to allow for settlement. If they are to remain in place for longer than 10 days, they should
be stabilized using vegetation, filter fabric, or other material. Diverted water should be directed
to a sediment trap or other sediment treatment area (UNEP 1994).
In addition to the broad applicability concerns described above, designers need to consider
conditions at the site level. In addition, they need to incorporate design features to improve the
longevity and performance of the practice while minimizing the maintenance burden.
Siting Considerations
In addition to considering the restrictions and adaptations of grassed swales to different regions
and land uses, designers must ensure that this management practice is feasible at the site in
question. Depending on the design option, grassed channels can be highly restricted practices
based on site characteristics.
Drainage Area. Grassed swales generally should treat small drainage areas of less than 5 acres.
If the practices are used to treat larger areas, the flows and volumes through the swale become
too large to achieve stormwater treatment through infiltration and filtration.
Slope. Grassed swales should be used on sites with relatively flat slopes (less than 4 percent).
Runoff velocities within the channel become too high on steeper slopes. This can cause erosion
and does not allow for infiltration or filtration in the swale.
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Soils /Topography. Grassed swales can be used on most soils, with some restrictions on the
most impermeable soils. In the dry swale, a fabricated soil bed replaces on-site soils to ensure
that runoff is filtered as it travels through the soils of the swale.
Ground Water. The depth to ground water depends on the type of swale used. In the dry swale
and grassed channel options, designers should separate the bottom of the swale from the ground
water by at least 2 feet to prevent a moist swale bottom or contamination of ground water. In the
wet swale option, treatment is enhanced by a wet pool, which is maintained by intersecting the
water table.
Design Considerations
Although the grass swale has different design variations, including the grassed channel, dry
swale, and wet swale, some design considerations are common to all three. One similarity is their
cross-sectional geometry. Swales should generally have a trapezoidal or parabolic cross-section
with relatively flat side slopes (flatter than 3:1). Designing the channel with flat side slopes
maximizes the wetted perimeter, which is the length along the edge of the swale's cross-section
where runoff flowing through the swale is in contact with the vegetated sides and bottom of the
swale. Increasing the wetted perimeter slows runoff velocities and provides more contact with
vegetation to encourage filtering and infiltration. Another advantage to flat side slopes is that
runoff entering the grassed swale from the side receives some pretreatment along the side slope.
The flat bottom of all three should be between 2 and 8 feet wide. The minimum width ensures an
adequate filtering surface for water quality treatment, and the maximum width prevents braiding
(the formation of small channels within the swale bottom).
Another similarity among all three designs is the type of pretreatment needed. A small forebay
should be used at the inflow area of the swale to trap incoming sediments. A pea gravel
diaphragm (a small trench filled with river run gravel) should be used to pretreat runoff entering
along the sides of the swale.
Two other features designed to enhance the treatment ability of grassed swales are a flat
longitudinal slope (generally between 1 and 2 percent) and a dense vegetative cover in the
channel. The flat slope helps to reduce the velocity of flow in the channel. Dense vegetation also
helps reduce velocities, protect the channel from erosion, and act as a filter to treat stormwater
runoff. During construction, it is important to stabilize the channel before the turf has been
established, either with a temporary grass cover or with the use of natural or synthetic erosion
control products.
In addition to treating runoff for water quality, grassed swales need to convey larger storms
safely. Typical designs allow the runoff from the 2-year storm to flow through the swale without
causing erosion. Swales should also have the capacity to pass larger storms (typically a 10-year
storm) safely.
The length of the swale necessary to infiltrate runoff can be calculated by using a mass balance
of runoff and infiltration for a triangular-shaped cross-sectional area.
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Design Variations
The following discussion identifies three different variations of open channel practices, including
the grassed channel, the dry swale, and the wet swale.
Grassed Channel. (Discussed in more length in subsection 7.5.1.2.1) Of the three grassed swale
designs, grassed channels are the most similar to a conventional drainage ditch, with the major
differences being flatter side slopes and longitudinal slopes and a slower design velocity for
water quality treatment of small storm events. Of all the grassed swale options, grassed channels
are the least expensive, but they also provide the least reliable pollutant removal performance.
The best application of a grassed channel is as pretreatment to other stormwater treatment
practices.
One major difference between the grassed channel and most of the other structural practices is
the method used to size the practice. Most water quality practices for stormwater management
are sized by volume. This method sets the volume available in the practice equal to the water
quality volume, or the volume of water to be treated in the practice. The grassed channel, on the
other hand, is a flow rate-based design. On the basis of the peak flow from the water quality
storm (this varies from region to region but a typical value is the 1-inch storm), the channel
should be designed so that runoff takes, on average, 10 minutes to flow from the top to the
bottom of the channel. A procedure for this design can be found in Design of Storm Water
Filtering Systems (CWP 1996).
Dry Swales. Dry swales are similar in design to bioretention areas. These practices incorporate a
fabricated soil bed into their design. The existing soil is replaced with a sand/soil mix that meets
minimum permeability requirements. An underdrain system is used under the soil bed. This
system is a gravel layer that encases a perforated pipe. Stormwater treated in the soil bed flows
through the bottom into the underdrain, which conveys this treated stormwater to the storm drain
system. Dry swales are a relatively new design, but studies of swales with a native soil similar to
the man-made soil bed of dry swales suggest high pollutant removal rates.
Wet Swales. Wet swales intersect the ground water and behave similarly to a linear wetland cell.
This design variation incorporates a shallow permanent pool and wetland vegetation to provide
stormwater treatment. This design also has potentially high pollutant removal. One disadvantage
of the wet swale is that its use in residential or commercial settings is unpopular because the
shallow standing water in the swale is sometimes viewed as a potential nuisance by property
owners.
Regional Variations
Cold Climates. In cold or snowy climates, swales can serve a dual purpose by acting as both a
snow storage/treatment practice and a stormwater management practice. This dual purpose is
particularly relevant when swales are used to treat road runoff. If used for this purpose, swales
should incorporate salt-tolerant vegetation, such as creeping bentgrass.
Arid Climates. In arid or semi-arid climates, swales should be designed with drought-tolerant
vegetation, such as buffalo grass. As pointed out in the Applicability discussion, the value of
vegetated practices for water quality needs to be weighed against the cost of water needed to
maintain them in arid and semi-arid regions.
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Section 7: Technology Assessment
Effectiveness
Swales act to control peak discharges in two ways. First, the grass reduces runoff velocity,
depending on the length and slope of the swale. Second, a portion of the stormwater runoff
volume passes through the swale and infiltrates into the soil. Table 7-7 summarizes grassed
swale pollutant removal efficiencies.
Table 7-7. Grassed Swale Pollutant Removal Efficiency Data
Study
Goldberg 1993
Seattle Metro and
Washington Department of
Ecology 1992
Seattle Metro and
Washington Department of
Ecology 1992
Wangetal. 1981
Dormanetal. 1989
Harper 1988
Kercher, Landon, and
Massarelli 1983
Harper 1988
Koon 1995
Yousefetal. 1985
Yousefetal. 1985
Welborn and Veenhuis
1987
Yu, Barnes, and Gerde
1993
Dormanetal. 1989
Pitt and McLean 1986
Oakland 1983
Dormanetal. 1989
Grassed swale removal efficiencies
TSS
67.8
60
83
80
98
87
99
81
67
~
~
0
68
65
0
33
-85
TP
4.5
45
29
~
18
83
99
17
39
8
-19.5
-25
60
41
~
-25
12
TN
~
~
~
84
99
40
~
13
8
-25
~
~
0
~
~
NO3
31.4
-25
-25
~
45
80
99
52
9
11
2
-25
~
11
~
~
-100
Metals
42-62
2-16
46-73
70-80
37-81
88-90
99
37-69
-35 to 6
14-29
41-90
0
74
14-55
0
20-58
14-88
Bacteria
-100
-25
-25
~
~
~
~
~
~
~
~
~
~
~
0
0
~
Type
Grassed channel
Grassed channel
Grassed channel
Dry swale
Dry swale
Dry swale
Dry swale
Wet swale
Wet swale
Drainage channel
Drainage channel
Drainage channel
Drainage channel
Drainage channel
Drainage channel
Drainage channel
Drainage channel
Limitations
Common problems associated with swales include excessive erosion along unlined channels
(usually because of excessive grade), erosion or sedimentation at the outlet point, or overtopping
of the dike at low points (UNEP 1994).
Additional limitations of the grass swale include the following:
Grassed swales cannot treat a very large drainage area.
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Section 7: Technology Assessment
Swales do not appear to be effective at reducing bacteria.
Wet swales can become a nuisance because of mosquito breeding.
If designed improperly (for example, improper slope), grassed channels will have
very little pollutant removal.
A thick vegetative cover is needed for these practices to function properly.
Maintenance
As with any BMP, swales must be maintained to continue to effectively remove pollutants.
Maintenance can include occasional mowing, fertilizing, and liming. In addition, any areas that
become damaged by erosion should be immediately repaired and replanted. The swales should
be protected from concentrated flows and be checked periodically for downstream obstructions.
Cost
To produce a conceptual cost approximation, grassed channel construction costs can be
developed using unit cost values. Shallow trenching (1 to 4 feet deep) with a backhoe in areas
not requiring dewatering can be performed for $4 to $5 per cubic yard of removed material (R.S.
Means 2000). Assuming no disposal costs (i.e., excavated material is placed on either side of the
trench), only the cost of fine grading, soil treatment, and grassing (approximately $2 per square
yard) should be added to the trenching cost to approximate the total construction cost. Site-
specific hydrologic analysis of the construction site is necessary to estimate the channel
conveyance requirement and the desired retention time in the swale. It is not unusual to have
flows on the order of 2 to 4 cfs per acre served.
For a design channel velocity of 1 foot per second, the resulting range in the channel cross-
section area can be as low as 2 but as high as 4 square feet per acre drained. If the average
channel flow depth is 1 foot, then the low estimate for grassed channel installation is $0.74 per
square foot of channel bottom per acre served per foot of channel length. The high estimate is
$1.48 per square foot of channel bottom per acre served per foot of channel length.
Table 7-8 summarizes additional costs of grass swales.
Table 7-8. Average Annual Operation and Maintenance Costs for a Grass Swale
Component
Mowing
General grass care
Debris/litter
removal
Reseeding/
fertilization
Estimated
unit cost
($)
0.89/100 m2
8. 8/100 m2
0.5 1/m2
0.35/m2
$ for swale size:
0.5m deep 0.3m
bottom width
3m top width
145.0
162.98
93.0
5.9
$ for swale size:
1m deep 1m
bottom width 7m
top width
241.0
274.0
93.0
10.37
Comments
Mow 2-3 times per year
Grass maintenance area is
(top width + 3 m) x length
Area revegetated is 1% of
maintenance area per year
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Section 7: Technology Assessment
Component
Inspection and
general
administration
TOTAL
Estimated
unit cost
($)
0.74/m2
$ for swale size:
0.5m deep 0.3m
bottom width
3m top width
231.0
638.0
$ for swale size:
1m deep 1m
bottom width 7m
top width
231.0
850.0
Comments
Inspection once per year
Source: Ellis 1998.
7.2.2.3. Temporary Storm Drain Diversion
General Description
A temporary storm drain diversion is a pipe that reroutes an existing drainage system to
discharge flow into a sediment trap or basin. This practice reduces the amount of sediment-laden
runoff from construction sites that enters waterbodies without treatment. Temporary storm drain
diversions can be used when a permanent stormwater drainage system has not yet been installed.
It should be recognized that diversion channels can also be installed but are not considered in the
following discussion.
Applicability
A temporary storm drain diversion should be used to temporarily redirect discharge to a
permanent outfall and should remain in place until the area draining to the storm sewer is no
longer disturbed. Temporary storm drain diversions can also be combined with other structures
and used as a sediment-trapping device when the completion of a permanent outfall has been
delayed; alternatively, a sediment trap can be placed below a permanent outfall to remove
sediment before the final flow discharge.
Design and Installation Criteria
Because the diversion is only temporary, the layout of piping and the overall impact of the
diversion's installation on post-construction drainage patterns must be considered. Once
construction is completed, the temporary diversion should be moved to restore the original
system. The following activities should be done at this time:
The storm drain should be flushed before the sediment trap is removed.
The outfall should be stabilized.
Graded areas should be restored.
State or local requirements should be checked for more detailed requirements and an
appropriate professional should certify that the design meets local hydrologic and
hydraulic requirements.
Effectiveness
If installed properly to capture the bulk of runoff from a construction site, temporary storm drain
diversions can be effective in reducing the discharge of sediment-laden, untreated water to
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Section 7: Technology Assessment
waterbodies. When used in combination with other erosion and sediment control practices such
as minimized clearing or vegetative and chemical stabilization, the level of pollution from a
construction site can be substantially reduced or eliminated.
Limitations
Installation of a temporary storm drain diversion can result in the disturbance of existing storm
drainage patterns. Care must be taken to ensure that the original system is properly restored once
the temporary system is removed. The most common source of problems is excessive velocity at
the outlet. Installation of an outlet stabilization structure is typically required and can be
constructed of riprap, reinforced concrete, geotextile linings, or a combination.
Maintenance
Once installed, temporary storm drain diversions require very little maintenance. Frequent
inspection and maintenance of temporary storm drain systems, especially after large storms,
should ensure that pipe clogging does not occur and that runoff from the site is being
successfully diverted. After removal of the temporary diversion, the permanent storm drain
system should be carefully inspected to ensure that drainage patterns have not been altered by the
temporary system.
Cost
Depending on the size of the construction site, a temporary storm drain diversion can be costly.
Costs include those associated with materials needed to construct the diversion and sediment trap
or basin (mainly piping, concrete, and gravel), and also labor costs for installation and removal
of the system, all of which could involve excavation, re-grading, and inspections. On the basis of
the variety of conditions that can affect storm drain diversion designs, typical costs per
installation are not presented here. However, site-specific cost estimates can be produced using
unit cost values along with site-specific quantity estimates. R.S. Means (2000) indicates a range
of pipe costs for surface placement, between $5.00 per linear foot for 4-inch diameter PVC
piping, and $9.20 per linear foot for 10-inch diameter PVC piping. On construction sites,
temporary inlets and outlets are usually formed by small rock-lined depressions. Assuming 4
cubic yards of crushed rock (1.5-inch mean diameter) per opening, an inlet and outlet combine to
add approximately $200 per pipe installation, based on $25 per cubic yard of stone (R.S. Means
2000).
7.2.2.4. Pipe Slope Drain
General Description
Pipe slope drains are used to reduce the risk of erosion on slopes by discharging runoff to
stabilized areas. Consisting of a metal or plastic flexible pipe if temporary, or pipes or paved
chutes if permanent, these drains carry surface runoff from the top to the bottom of a slope that
has already been damaged by erosion or is at high risk for erosion. These drains are also used to
drain saturated slopes that have the potential for soil slides.
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Section 7: Technology Assessment
Applicability
Temporary slope drains can be used on most disturbed slopes to eliminate gully erosion
problems resulting from concentrated flows discharged at a diversion outlet. Slope drains should
be used as a temporary measure for as long as the drainage area remains disturbed. They will
need to be moved once construction is complete and a permanent storm drainage system is
established. Appropriate restoration measures will then need to be taken, such as adjusting
grades and flushing sediment from the pipe before it is removed (UNEP 1994).
Design and Installation Criteria
Pipe slope drains can be placed directly on the ground or buried under the surface. The inlet
should be at the top of the slope and should be fitted with an apron, attached with a watertight
connection. Filter cloth should be placed under the inlet to prevent erosion. Flexible pipes, which
are positioned on top of the ground, should be securely anchored with grommets placed 10 feet
on center. The outlet at the bottom of the slope should also be stabilized with riprap. The riprap
should be placed along the bottom of a swale that leads to a sediment-trapping structure or
another stabilized structure.
Slope drain pipe sizes are based on drainage area and the size of the design storm. Pipes should
be connected to a diversion ridge at the top of the slope by covering it with compacted fill
material where it passes through the ridge. Discharge from a slope drain should be to a sediment
trap, sediment basin, or other stabilized outlet (UNEP 1994).
Pipe slope drains should be installed perpendicular to the contour down the slope, and the design
should be able to handle the peak runoff for the 10-year storm. Recommendations of slope drain
diameter are summarized in Table 7-9 (NAFffi, No Date).
Recently graded slopes that do not have permanent drainage measures installed should have a
temporary slope drain and a temporary diversion installed. A temporary slope drain used in
conjunction with a diversion conveys stormwater flows and reduces erosion until permanent
drainage structures are installed.
The following are design recommendations for temporary slope drains:
The drain should consist of heavy-duty material manufactured for the purpose and
have grommets for anchoring at a spacing of 10 feet or less.
Minimum slope drain diameters should be observed for varying drainage areas.
Table 7-9. Recommended Pipe/Tubing Sizes for Slope Drains
Maximum drainage
area
(acres)
0-0.5
0.5
0.75
1.0
1.5
Pipe/tubing
diameter1
(inches)
12
18
Pipe/tubing diameter2
(inches)
12
18
Pipe/tubing
diameter3
(inches)
8
10
12
Individually designed
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Section 7: Technology Assessment
Maximum drainage
area
(acres)
2.5
3.5
5.0
Pipe/tubing
diameter1
(inches)
21
24
30
Pipe/tubing diameter2
(inches)
24
Pipe/tubing
diameter3
(inches)
1 UNEP 1994.
2USDOT1995.
3IDNR 1992.
The entrance to the pipe should consist of a standard flare end section of corrugated
metal. The corrugated metal pipe should have watertight joints at the ends. The rest of
the pipe is typically corrugated plastic or flexible tubing, although for flatter, shorter
slopes, a polyethylene-lined channel is sometimes used.
The height of the diversion at the pipe should be the diameter of the pipe plus 0.5
foot.
The outlet should be placed at a reinforced or erosion-resistant location.
Temporary slope drains should be designed to adequately convey runoff for a desired frequency
storm, typically either 2 years or 10 years depending on local regulations. Both the size and the
spacing can be determined on the basis of the contributing drainage area. Drains are spaced at
intervals corresponding to the specified drainage areas. For larger drainage areas and critical
locations, the drains should be sized on an individual basis (USDOT 1995).
Slope drains should be constructed in conjunction with diversion berms such that the berms are
not overtopped. At the pipe inlet, the top of the berm should be a minimum of 300 mm (11.81
inches) higher than the top of the pipe. The entrance should be constructed of a standard flared
end section or a Tee section if designed properly. The entrance should be placed in a sump that is
depressed 150 mm (5.90 inches) (USDOT 1995).
The outlet of the slope drain must be protected with a riprap apron. If the slope drain is draining
a disturbed area and sufficient right-of-way is available, the drain could empty into a sediment
trap (USDOT 1995). Table 7-10 summarizes slope drain characteristics.
Effectiveness
There is no information on the effectiveness of pipe slope drains.
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Table 7-10. Slope Drain Characteristics
Capacity
Material
Inlet section
Connection to ridge at top
of slope
Outlet
2-year frequency, 24-hour-duration storm event
Strong, flexible pipe, such as heavy duty, nonperforated, corrugated
plastic
Standard T or L flared-end section with metal toe plate
Compacted fill over pipe with minimum dimensions, 1.5-foot depth, 4-
foot top width, and 6 inches higher than ridge
Pipe extends beyond toe of slope and discharges into a sediment trap or
basin unless contributing drainage area is stable
Source: IDNR 1992.
Limitations
The area drained by a temporary slope drain should not exceed 5 acres. Physical obstructions
substantially reduce the effectiveness of the drain. A common slope drain problem is overtopping
of the inlet due to an undersized or blocked pipe, or erosion at the outlet point due to insufficient
protection (UNEP 1994). Other concerns are failures from overtopping because of inadequate
pipe inlet capacity and reduced diversion channel capacity and ridge height.
WashoutA washout along a pipe due to seepage and piping can be caused by
inadequate compaction, insufficient fill, or installation that might be too close to the
edge of the slope.
Overtopping caused by undersized or blocked pipeThe drainage area might be too
large.
Overtopping caused by improper grade of channel and ridgeA positive grade
should be maintained.
Overtopping caused by poor entrance conditions and trash buildup at the pipe inlet
Deepen and widen the channel at the pipe entrance and frequently inspect and clear
the inlet.
Erosion at outletThe pipe should be extended to a stable grade or an outlet
stabilization structure is needed.
Displacement or separation of pipeThe pipe should be tied down and the joints
secured.
Maintenance
Pipe slope drains must be inspected after each significant runoff event for evidence of erosion
and uncontrolled runoff. Any repairs to the drain should be made immediately. Significant
amounts of sediment trapped at the outfall should also be removed in a timely manner and
disposed of properly (NAHB, No Date).
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The following actions should be taken to properly maintain a pipe slope drain (TDNR 1992):
Inspect slope drains and supporting diversions once a week and after every storm
event.
Check the inlet for sediment or trash accumulation; clear and restore to proper
entrance condition.
Check the fill over the pipe for settlement, cracking, or piping holes; repair
immediately.
Check for holes where the pipe emerges from the dike; repair immediately.
Check the conduit for evidence of leaks or inadequate anchoring; repair immediately.
Check the outlet for erosion or sedimentation; clean and repair, or extend if
necessary.
Once slopes have been stabilized, remove the temporary diversions and slope drains,
and stabilize all disturbed areas.
Cost
The cost of pipe slope drains and their installation varies with the design and materials used.
Site-specific cost estimates can be produced using unit cost values with site-specific quantity
estimates.
R.S. Means (2000) indicates a range of pipe costs for surface placement between $5.00 per linear
foot for 4-inch diameter PVC piping, and $9.20 per linear foot for 10-inch diameter PVC piping.
On construction sites, temporary inlets and outlets are usually formed by small rock-lined
depressions. Assuming 4 cubic yards of crushed rock (1.5-inch mean diameter) per opening, an
inlet and outlet together add approximately $200 per pipe installation, based on $25 per cubic
yard of stone (R.S. Means 2000).
7.2.2.5. Stone Check Dam
General Description
A check dam is a small temporary barrier constructed across a drainage channel or swale to
reduce the velocity of the flow. By reducing the flow velocity, the erosion potential is reduced,
detention times are lengthened, and more sediments are able to settle out of the water column.
Check dams can be constructed of stone, gabions, treated lumber, or logs (NAHB, No Date).
Check dams are inexpensive and easy to install. They can be used permanently to settle
sediment, reduce the velocity of runoff, and provide aeration. However, the use of check dams in
a channel should not be a substitute for the use of other sediment-trapping and erosion control
measures. As with most other temporary structures, check dams are most effective when used in
combination with other stormwater and erosion and sediment control measures.
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Applicability
Check dams are commonly used (1) in channels that are degrading but where permanent
stabilization is impractical because of their short period of usefulness and (2) in eroding channels
where construction delays or weather conditions prevent timely installation of erosion-resistant
linings (IDNR 1992).
Check dams are also useful in steeply sloped swales, in small channels, in swales where adequate
vegetative protection cannot be established, or in swales or channels that will be used for a short
period of time where it is not practical to line the channel or implement other flow control
practices (USEPA 1993). In addition, check dams are appropriate where temporary seeding has
been recently implemented but has not had time to fully develop and take root. The contributing
drainage area should range from 2 to 10 acres. Check dams should be used only in small open
channels that will not be overtopped by flow once the dams are built and should not be built in
stream channels, either intermittent or perennial (UNEP 1994).
Design and Installation Criteria
Check dams can be constructed from a number of different materials. Most commonly, they are
made of rock, logs, sandbags, or straw bales. Rock or stone is often preferred because of its cost-
effectiveness and longevity. Logs and straw bales will decay with time and are not recommended
because they can cause waterway blockage if they fail. When using rock or stone, the material
diameter should be 2 to 15 inches. The stones should be extended 18 inches beyond the banks,
and the side slopes should be 2:1 or flatter. Lining the upstream side of the dam with a foot of 1-
to 2-inch gravel can improve the efficiency of the dam (NAHB, No Date). Logs should have a
diameter of 6 to 8 inches. Regardless of the material used, careful construction of a check dam is
necessary to ensure its effectiveness.
The distance between rock check dams will vary depending on the slope of the ditch, with closer
spacing when the slope is steeper. The size of stone used in the check dam should also vary with
the expected design velocity and discharge. As velocity and discharge increase, the rock size
should also increase. For most rock check dams, 3 inches to 12 inches is a suitable stone size. To
improve the sediment-trapping efficiency of check dams, a filter stone can be applied to the
upstream face. A well-graded coarse aggregate that is less than 1 inch in size can be used as a
filter stone.
All check dams should have a maximum height of 3 feet. The center of the dam should be at
least 6 inches lower than the edges. This design creates a weir effect that helps to channel flows
away from the banks and prevent further erosion. Additional stability can be achieved by
implanting the dam material approximately 6 inches into the sides and bottom of the channel
(VDCR 1995).
When installing more than one check dam in a channel, outlet stabilization measures should be
installed below the final dam in the series. Because this area is likely to be vulnerable to further
erosion, riprap or some other stabilization measure is highly recommended.
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Effectiveness
Field experience has shown that rock check dams are more effective than silt fences or straw
bales to stabilize wet-weather ditches (VDCR 1995). Straw bales have been shown to have very
low trapping efficiencies and should not be used for check dams. For long channels, check dams
are most effective when used in a series, creating multiple barriers to sediment-laden runoff.
Limitations
Check dams should not be used in perennial streams unless approved by an appropriate
regulatory agency (USEPA 1992; VDCR 1995). Because the primary function of check dams is
to slow runoff in a channel, they should not be used as a stand-alone substitute for other
sediment-trapping devices. Also, leaves have been shown to be a significant problem, as they
clog check dams; therefore, increased inspection and maintenance might be necessary in the fall.
Common problems with check dams include channel bypass and severe erosion when
overtopped and ineffectiveness due to accumulated sediment and debris. When designing check
dams, the fact that they will reduce the capacity of a channel to transmit stormwater runoff and
thus will need to be sized appropriately should be taken into account (UNEP 1994). The check
dam could also kill grass linings in the channel if the water level remains high after it rains or if
there is significant sedimentation. In addition, a check dam might reduce the hydraulic capacity
of the channel and create turbulence, which erodes the channel banks (NAHB, No Date).
Maintenance
Check dams should be inspected periodically to ensure that they have not been repositioned as a
result of stormwater flow. In addition, the center of a check dam should always be lower than its
edges. Additional stone might have to be added to maintain the correct height. Sediment should
not be allowed to accumulate to more than half the original dam height. Any required
maintenance should be performed immediately. When check dams are removed, care must be
taken to remove all dam materials to ensure proper flow within the channel. The channel should
subsequently be seeded for stabilization (NAHB, No Date).
Cost
The cost of check dams varies according to the material used for construction and the width of
the channel to be dammed. In general, it is estimated that check dams constructed of rock cost
about $100 per dam (USEPA 1992). Brown and Schueler (1997) estimated that a rock check dam
would cost approximately $62 per installation, including the cost for filter fabric bedding. Other
materials, such as logs and sandbags, might be a less expensive alternative, but they could
require higher maintenance costs.
7.2.2.6. Lined Waterways
General Description
Lined channels convey stormwater runoff through a stable conduit. Vegetation lining the channel
reduces the flow velocity of concentrated runoff. Lined channels usually are not designed to
control peak runoff loads by themselves and are often used in combination with other BMPs
such as subsurface drains and riprap stabilization. Where moderately steep slopes require
drainage, lined channels can include excavated depressions or check dams to enhance runoff
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storage, decrease flow rates, and enhance pollutant removal. Peak discharges can be reduced
through temporary detention in the channel. Pollutants can be removed from stormwater by
filtration through vegetation, by deposition, or in some cases by infiltration of soluble nutrients
into the soil. The degree of pollutant removal in a channel depends on the residence time of the
water in the channel and the amount of contact with vegetation and the soil surface, but pollutant
removal is not generally the major design criterion.
Often construction increases the velocity and volume of runoff, which causes erosion in newly
constructed or existing urban runoff conveyance channels. If the runoff during or after
construction will cause erosion in a channel, the channel should be lined or flow control practices
instituted. The first choice of lining should be grass or sod because this reduces runoff velocity
and provides water quality benefits through filtration and infiltration. If the velocity in the
channel would erode the grass or sod, one can use riprap, concrete, or gabions (USEPA 2000).
Geotextile materials can be used in conjunction with either grass or riprap linings to provide
additional protection at the soil-lining interface.
Applicability
Lined channels typically are used in residential developments, along highway medians, or as an
alternative to curb and gutter systems. Grass-lined channels should be used to convey runoff only
where slopes are 5 percent or less. These channels require periodic mowing, occasional spot-
seeding, and weed control to ensure adequate grass cover (UNEP 1994).
Lined channels should be used in areas where erosion-resistant conveyances are needed, such as
in areas with highly erodible soils and slopes of less than 5 percent. They should be installed
only where space is available for a relatively large cross-section. Grassed channels have a limited
ability to control runoff from large storms and should be used with the recommended allowable
velocities for the specific soil types and vegetative cover.
Design and Installation Criteria
The design of a lined waterway requires proper determination of the channel dimensions. It must
ensure that (1) the velocity of the flowing water will not wash out the waterway and that (2) the
capacity of the waterway is sufficient to carry the surface flow from the watershed without
overtopping.
Vegetation-Lined Channels. Grass-lined channels have been previously discussed in detail and
are only summarized in this section. The allowable velocity of water in the waterway depends
upon the type, condition, and density of the vegetation, as well as the erosive characteristics of
the soil. Uniformity of vegetative cover is important because the stability of the most sparsely
covered area determines the stability of the channel. Grasses are a better vegetative cover than
legumes because grasses resist water velocity more effectively.
Vegetative-lined channels can have triangular, parabolic, or trapezoidal cross-sections. Side
slopes should not exceed 3:1 to facilitate the establishment, maintenance, and mowing of
vegetation. A dense cover of hardy, erosion-resistant grass should be established as soon as
possible following grading. This might necessitate the use of straw mulch and the installation of
protective netting until the grass becomes established. If the intent is to create opportunities for
runoff to infiltrate into the soil, the channel gradient should be kept near zero, the channel bottom
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must be well above the seasonal water table, and the underlying soils should be relatively
permeable (generally, with an infiltration rate greater than 2 centimeters [0.78 inches] per hour).
Rock-Lined Channels. Riprap-lined channels can be installed on somewhat steeper slopes than
grass-lined channels. They require a foundation of filter fabric or gravel under the riprap.
Generally, side slopes should not exceed 2:1, and riprap thickness should be 1.5 times the
maximum stone diameter. Riprap should form a dense, uniform, well-graded mass (UNEP 1994).
Lined channels should be sited in accordance with the natural drainage system and should not
cross ridges. The channel design should not have sharp curves or significant changes in slope.
Channels should not receive direct sedimentation from disturbed areas and should be established
only on the perimeter of a construction site to convey relatively clean stormwater runoff. They
should also be separated from disturbed areas by a vegetated buffer or other BMP to reduce
sediment loads.
Basic design recommendations for lined channels include the following:
Construction and vegetation of the channel should occur before grading and paving
activities begin.
Design velocities should be less than 5 feet per second.
Geotextiles can be used to stabilize vegetation until it is fully established.
Covering the bare soil with sod or geotextiles can provide reinforced stormwater
conveyance immediately.
Triangular-shaped channels should be used with low velocities and small quantities of
runoff; parabolic grass channels are used for larger flows and where space is
available; trapezoidal channels are used with large flows of low velocity (low slope).
Outlet stabilization structures might be needed if the runoff volume or velocity has
the potential to exceed the capacity of the receiving area.
Channels should be designed to convey runoff from a 10-year storm without erosion.
The sides of the channel should be sloped less than 3:1, with V-shaped channels
along roads sloped 6:1 or less for safety.
All trees, bushes, stumps, and other debris should be removed during construction.
Effectiveness
Lined channels can effectively transport stormwater from construction areas if they are designed
for expected flow volumes and velocities and if they do not receive sediment directly from
disturbed areas.
Limitations
Lined channels, if improperly installed, can alter the natural flow of surface water and have
adverse impacts on downstream waters. Additionally, if the design capacity is exceeded by a
large storm event, the vegetation might not be sufficient to prevent erosion and the channel might
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be destroyed. Clogging with sediment and debris reduces the effectiveness of grass-lined
channels for storm water conveyance.
Common problems in lined channels include erosion of the channel before vegetation is fully
established and gullying or head cutting in the channel if the grade is too steep. In addition, trees
and brush tend to invade lined channels, causing maintenance problems.
Riprap-lined channels can be designed to safely convey greater runoff volumes on steeper slopes.
However, they should generally be avoided on slopes exceeding 10 percent because stone
displacement, erosion of the foundation, or channel overflow and erosion resulting from a
channel that is too small can occur. Thus, channels established on slopes greater than 10 percent
will usually require protection with rock gabions, concrete, or other highly stable and protective
surfaces (UNEP 1994).
Maintenance
Maintenance requirements for lined channels are relatively minimal. During the vegetation
establishment period, the channels should be inspected after every rainfall. Other maintenance
activities that should be carried out after vegetation is established are mowing, litter removal, and
spot vegetation repair. The most important objective in the maintenance of lined channels is
maintaining a dense and vigorous growth of turf. Periodic cleaning of vegetation and soil buildup
in curb cuts is required so that water flow into the channel is unobstructed. During the growing
season, channel grass should be cut no shorter than the level of design flow, and the cuttings
should be removed promptly.
Cost
Costs of grassed channels range according to depth, with a 1.5-foot-deep, 10-foot-wide grassed
channel estimated at $6,395 to $17,075 per trench, while a 3-foot-deep, 21-foot-wide grassed
channel is estimated at $12,909 to $33,404 per trench (SWRPC 1991).
EPA also refers readers to the discussion of costs for grass-lined channels, which contains many
of the design and cost elements required for installing lined waterways. Designers have a range
of options for lining new channels. Geosynthetic TRMs can be used for immediate erosion
protection in channels exposed to runoff flows. The Erosion Control Technology Council (a
geotextile industry support association) suggests TRMs cost approximately $7.00 per square yard
(installed) for channel protection (ECTC 2002a). R.S. Means indicates machine-placed riprap
costs of approximately $40 per cubic yard. The riprap maximum size is typically between 6 and
12 inches, depending on the channel design velocity. A cubic yard of riprap will cover between
36 and 18 square feet of channel bed for these riprap sizes (assuming depth of riprap is 1.5 times
the maximum size). These estimates suggest that riprap lining will be between $10 and $20 per
square foot of channel (costs include materials, labor, and equipment, with overhead and profit).
7.2.3. SEDIMENT TRAPPING DEVICES
The devices listed under this group of BMPs trap sediment primarily through impounding water
and allowing for settling to occur (Haan et al. 1994). Silt fence, super silt fence, straw bale dikes,
sediment traps, and sediment basins all control flow through a porous flow control system such
as filter fabric or straw bales or they use a dam to impound water with a pipe, open channel, or
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rock fill outlet. The filtering capacity of silt fence (filter fabric) contributes only a small amount
of trapping, but serves to make the fence less porous and hence increases ponding. For steady-
state flows, the trapping that occurs behind the flow control device can be shown to be directly
proportional to the surface area and indirectly proportional to flow through the system (Haan et
al. 1994). The ratio of the surface area to flow is known as the overflow rate, and trapping in
such systems is predicted by the ratio of overflow rate to particle settling velocity. Although
flows in nature are inherently non-steady-state and more complex than steady-state systems,
studies have shown that the best predictor of trapping in such systems is still the ratio of settling
velocity to overflow rate (Hayes et al. 1984). In the case of non-steady-state, the overflow rate is
best defined by the ratio of peak discharge to surface area (Hayes et al. 1984; McBurnie et al.
1990).
The amount of trapping in these structures depends on the size of the structure, flow rates into
the system, hydraulics of the flow control system, the size distribution of the sediment flowing
into the structure, and the chemistry of the sediment-water system (Haan et al. 1994). Trapping
can be enhanced by chemical treatment of flows into the structure, but the impacts have not been
widely defined for varying mineralogy and chemistry of the sediment-water system (Haan et al.
1994; Tapp and Barfield 1986). Recent studies have been conducted on the application of
polyacrylamides (PAM) to disturbed areas for enhancing settling (Benik et al. 1998; Masters et
al. 2000; Roa-Espinosa et al. 2000), but results have not been definitive. No known studies have
evaluated the effects of PAM application to disturbed areas on settling in sediment trapping
devices.
Sediment flowing into sediment trapping devices is composed of primary particles and
aggregated particles. Aggregates are formed when clays, silts, and sands are cemented together
to form larger particles that have settling velocities far greater than those of any individual
particles alone, although the degree of aggregation depends on the amount of cementing material
present (typically clays and organic matter). Because the aggregates have higher settling
velocities than primary particles, the degree of aggregation that is present has a large effect on
the trapping that occurs. Procedures are available to measure the combined size distribution of
aggregate and primary particle size distribution (Barfield et al. 1979; Haan et al. 1994).
Procedures are also available to predict particle size distributions of aggregates and primary
particles (Foster et al. 1985).
In the absence of chemical treatment, the sediment that can be captured in sediment trapping
devices is typically the larger settleable solids. To trap the smaller size clay particles, structures
with surface areas larger than the construction site itself would have to be built in many cases
(Barfield 2000). Chemical treatment can be used to reduce the size captured, but it has not been
adopted on a wide scale because of the cost and complexity of the operation (Tapp et al. 1981).
Sediment trapping devices also provide some stormwater detention by virtue of detaining flows
long enough to allow sediment to settle out and be deposited. However, to operate as a
stormwater detention structure, the design should include adequate volume for detention.
Virtually all the available information on sediment trapping structures, both theoretical and
experimental, is on impacts to receiving waters and not downstream effects. In a very limited
analysis, Barfield (2000) combined the SEDIMOT II computer model together with the
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FLUVIAL model to theoretically evaluate the effect of sediment trapping structures on
downstream geomorphology in a Puerto Rican watershed.
7.2.3.1. Silt Fence
General Description
Silt fences are used as temporary sediment barriers consisting of filter fabric anchored across and
supported by posts. Their purpose is to retain sediment from small disturbed areas by reducing
the velocity of sediment-laden runoff and promoting sediment deposition (Smolen et al. 1988).
Silt fences capture sediment by ponding water and allowing for deposition, not by filtration. Silt
fence fabric first screens silt and sand from runoff, resulting in clogging of the lower part of the
fence. The pooling water allows sediments to settle out of the runoff. Silt fences work best in
conjunction with temporary basins, traps, or diversions.
Applicability
Silt fences are generally placed at the toe of fills, along the edge of waterways, and along the site
perimeter. The fences should not be used in drainage areas with concentrated and high flows, in
large drainage areas, or in ditches and swales where concentrated flow is present.
The drainage area for the fence should be selected on the basis of design storms and local
hydrologic conditions so that the silt fence is not expected to overtop. A typical design calls for
no greater than one-quarter acre of drainage area per 100 feet offence, but this is highly variable
depending on climate. The fence should be stable enough to withstand runoff from a 10-year
peak storm. Table 7-11 lists the maximum slope length specified by the U.S. Department of
Transportation (USDOT). These slope lengths should be based on sediment load and flow rates.
This would mean that the values given below should be adjusted for climatic conditions instead
of one size fits all to ensure maximum effectiveness.
Table 7-11. Maximum Slope Lengths for Silt Fences
Slope
(%)
<2
5
10
20
25
30
35
40
45
50
18-inch (460 mm) fence
250 ft (75 m)
100 ft (30m)
50 ft (15m)
25 ft (8 m)
20 m (6 ft)
15 ft (5m)
15 ft (5m)
15 ft (5m)
10 ft (3m)
10 ft (3m)
30-inch (760 mm) fence
500 ft (150m)
250 ft (75 m)
150 ft (45m)
70 ft (21m)
55 ft (17m)
45 ft (14m)
40 ft (12m)
35 ft (10m)
30 ft (9 m)
25 ft (8 m)
Source: USDOT 1995.
Typical standards and specifications call for the silt fence to be on fairly level ground and follow
the land contour, although it is recognized that a slight slope can occur along the fence in spite of
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the best installation practices. Runoff can move down the contour until a weak spot occurs in the
buried toe and undercuts the fence. Alternatively, flow might move to a low spot where it
accumulates and causes an overtopping. In either case, trapping by the silt fence is essentially
zero, and flows will then have been concentrated, causing downslope erosion.
Design and Installation Criteria
Design criteria are of two types:
Hydrologic design for a required trapping of sediment and flow rate to pass the design
storm
Selection of appropriate installation criteria such that the silt fence will perform as
designed
Hydrologic Design
The fence should be designed to pass the design storm without causing damage while trapping
the required amount of sediment. It is necessary to use either a database or some type of model to
develop the appropriate hydrologic design. Efforts to model the sediment trapping that occurs
through the use of a silt fence have resulted in models that predict the settling in the ponded area
upstream from the fence (Barfield et al. 1996; Lindley et al. 1998). The results from model
simulations show that trapping depends primarily on the surface area of the impounded water
and the flow rate through the filter. The models use a clear water flow rate, typically specified by
the manufacturer, to predict discharge. However, numerous studies have shown that sediment
laden flows cause clogging of the geotextiles used to construct the fence, depending on the
opening size and size of the sediment (Britton et al. 2001; Wyant 1980; Barrett et al. 1995;
Fisher and Jarret 1984). Thus, results from model studies to date are suspect and need to be
modified to account for the effects of clogging on flow rate. Barfield et al., (2001) developed a
model of flow rate using conditional probability concepts, but the results have not been
experimentally verified.
Design aids have been developed for silt fence, using simulations from the SEDEVIOT III model
(Hayes and Barfield 1995). In the model, predictions are made about trapping efficiency using the
ratio of settling velocity for the dis of the eroded sediment, divided by the ratio of discharge to
ponded surface area.4 The design aids yield conservative estimates as compared to the SEDEVIOT
III model, but the database used for generating the design aid is based on the assumption that
clogging does not affect flow rates. The discussion above shows that assumption to be erroneous.
SEDCAD takes the approach of using a slurry flow rate, not a clean water flow rate, when it
simulates fence effectiveness, reporting slurry rates ranging between 0.1 and 15 gpm/sq. ft. On
the basis of this discussion, one can conclude that it is difficult to predict with accuracy the
trapping efficiency of silt fence under a given set of conditions. In addition, the quality of
installation and maintenance are important to the long-term performance of the fence. The best
available estimate of sediment trapping obtained from modeling of hydrologic events should be
applied with care in any site design problem.
4 d15:15 percent by weight of suspended solids are smaller than those that are trapped by this device; similarly dso
indicates that 50 percent by weight of suspended solids are smaller than those trapped
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Installation Criteria
General installation criteria for the silt fence should incorporate the following factors:
The fabric must have sufficient strength to counter forces created by contained water
and sediment (Sprague 1999).
The posts must have sufficient strength to counter the forces transferred to them by
the fabric (Sprague 1999).
The fabric must be installed to ensure that the loads are all adequately transferred
through the fabric to the posts or the ground without overstressing (Sprague 1999).
The fence must be designed on the basis of site-specific hydrologic and soil
conditions such that it will not overtop during design events.
The fence must be installed (anchored) with a buried toe of sufficient depth so that it
does not become detached from the soil surface.
In general, the fence requires a metal wire backing to provide sufficient strength to
prevent failure from the weight of trapped sediment and to prevent the toe of the
fabric from being removed from the ground.
Maximum drainage area behind the fence should be determined on the basis of the
local rainfall and the infiltration characteristics of the soil and cover.
Silt fence material is typically synthetic filter fabric or a pervious sheet of polypropylene, nylon,
polyester, or polyethylene yarn. The fabric should have ultraviolet ray inhibitors and stabilizers
to provide for a minimum useful construction life of 6 months or the duration of construction,
whichever is greater. The height of the fence fabric should not exceed 3 feet. If standard strength
filter fabric is used, it should be reinforced with a wire fence, extending down into the trench that
buries the toe. The wire should be of sufficient strength to support the weight of the deposited
sediment and water. In general, a minimum 14 gauge and a maximum mesh spacing of 6 inches
is called for (Smolen et al. 1988). Typical requirements for the silt fence physical properties, as
specified in selected local BMP standards and specifications, are presented in Table 7-12.
Table 7-12. Typical Requirements for Silt Fence Fabric
Physical property
Filtering Efficiency
Tensile Strength
at 20% (maximum)
Elongation
Slurry Flow Rate
Water Flow Rate
UV Resistance
Requirements
Woven fabric
85%
Standard Strength 30 pound/linear inch
Extra Strength 50 pound/linear inch
0.3 gallon/square feet/minute
15 gallons/square feet/minute
70%
Non-woven fabric
85%
Standard Strength 50 pound/linear inch
Extra Strength 70 pound/linear inch
4.5 gallons/square feet/minute
220 gallon/square feet/minute
85%
Source: NCDNR 1988; IDNR 1992.
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It should be pointed out that these numbers, particularly the flow rates, can vary widely
depending on the local soil condition because of possible clogging of the filter material.
Material for the posts used to anchor the filter fabric can be constructed of either wood or steel.
Wooden stakes should be buried at a depth sufficient to keep the fence, when loaded with
sediment and water, from falling over. The depth of burial should depend on post diameter and
soil strength characteristics when saturated. Many standards and specifications set a minimum
post length of 5 feet with 4-inch diameter for posts composed of softwood (e.g., pine) and 2-inch
diameter for posts composed of hardwood (e.g., oak) (Smolen et al. 1988). Steel posts should
also be designed on the basis of local wet soil strength characteristics. Some standards and
specifications for these posts set a minimum weight of 1.33 pounds per linear feet with a
minimum length of 4 feet. Steel posts should also have projections to adhere filter fabric to the
post (Smolen et al. 1988).
A silt fence should be erected continuously from a single roll of fabric to eliminate unwanted
gaps in the fence. If a continuous roll of fabric is not available, the fabric should overlap from
both directions only at posts with a minimum overlap of 6 inches and be rolled together with a
special flexible rod to keep the ends from separating. Fence posts should be spaced at a distance
on the basis of wet soil strength characteristics and post size and strength; generally, the posts are
spaced approximately 4 to 6 feet apart. If standard strength fabric is used in combination with
wire mesh, the spacing can be larger. Typically, standards and specifications call for the posts to
be no more than 10 feet apart. If extra-strength fabric is used without wire mesh reinforcement,
some standards call for the support posts to be spaced no more than 6 feet apart (VDCR 1995).
Again, this spacing should depend on wet soil strength characteristics and post size.
A silt fence must provide sufficient storage capacity or be stabilized over flow outlets such that
the storage volume of water will not overtop the fence. The return period event (size of the
rainfall event managed) used for design is typically a prerogative of the regulatory agency. For
temporary fences, a 2-year storm event is typically used as a design standard. Fences that will be
in place for 6 months or longer are commonly designed for a 10-year storm event (Sprague
1999). The space behind the fence used for impoundment volume must be sufficient to
adequately contain the sediment that will be deposited. Each storm will deposit sediment behind
the fence, and after a period of time, the amount of sediment accumulated will render the fence
useless. Frequency offence management is a function of its sizing (i.e. whether the fence was
installed for a 2-year or a 10-year storm event) (Sprague 1999) and the amount of erosion that
occurs in the area draining to the fence.
Effectiveness
The performance of silt fences has not been well defined. Laboratory studies using carefully
controlled conditions have shown trapping efficiencies in the range of 40 to 100 percent,
depending on the type of fabric, overflow rate, and detention time (Barrett et al. 1995; Wyant
1980; Wishowski et al. 1998). Field studies have been limited and quite inadequate; however, the
results show that field-trapping efficiencies are very low. In fact, Barrett et al. (1995) obtained a
value of zero percent trapping averaged over several samples with a standard error of 26 percent.
Barrett et al. (1995) cite the following reasons for the field tests not showing the expected
results:
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Inadequate fabric splices
Sustained failure to correct fence damage resulting from overtopping
Large holes in the fabric
Under-runs due to inadequate toe-ins
Silt fence damaged and partially covered by the temporary placement of stockpiles of
materials
Silt fences are effective at removing large particle sediment, primarily aggregates, sands, and
larger silts. Sediment is removed through impounding of water to slow velocity. It is argued that
the silt fence will not contribute to a reduction in small particle sediment and is not effective
against other pollutants (WYDEQ 1999). EPA (1993) reports the following effectiveness ranges
for silt fences constructed of filter fabric: average TSS removal of 70 percent, sand removal of
80 to 90 percent, silt-loam removal of 50 to 80 percent, and silt-clay-loam removal of 0 to 20
percent. However, the EPA numbers from the Nationwide Urban Runoff Program should not be
considered to apply to every location. The actual trapping will vary widely for a given design
because of differences in hydrologic regimes and soil types.
The advantages of using silt fences include minimal labor requirement for installation, low cost,
high efficiency in removing sediment, durability, and sometimes reuse (Sprague 1999). Silt
fences are the most readily available and cost-effective control options where options like
diversion are not possible. Silt fences are also a popular choice because contractors have used
them extensively and their familiarity makes silt fence use more likely for future construction
activities. The visibility of a silt fence is also an advantage (i.e., the fence is advertising the use
of erosion and sediment control practices). In addition, the silt fence visibility makes site
inspection easier for contractors and government inspectors (CWP 1996).
Limitations
Silt fences should not be installed along areas where rocks or other hard surfaces will prevent
uniform anchoring offence posts and entrenching of the filter fabric because an insufficient
anchor will greatly reduce their effectiveness and might create runoff channels. In addition, open
areas where wind velocity is high could present a maintenance challenge, as high winds might
accelerate deterioration of the filter fabric (Smolen et al. 1988). When the pores of the silt fence
fabric become clogged with sediment, pools of water are likely to form uphill of the fence. Siting
and design of the silt fence should account for this problem, and care should be taken to avoid
unnecessary diversion of stormwater from these pools which might cause further erosion
damage. Silt fences can act as a diversion if placed slightly off-contour and can control shallow,
uniform flows from small, disturbed areas and deliver sediment-laden water to deposition areas.
Silt fences will sag or collapse if a site is too large, if too much sediment accumulates, if the
approach slope is too steep, or if the fence was not adequately supported. If the fence bottom is
not properly installed or the flow velocity is too fast, fence undercuts or blowouts can occur
because of excess runoff. Erosion around the end of the fence can occur if the fence ends do not
extend upslope to prevent flow around the fence (IDNR 1992).
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Maintenance
Site operators should inspect silt fences after each rainfall event to ensure they are intact and that
there are no gaps at the fence-ground interface or tears along the length of the fence. If gaps or
tears are found, they should be repaired or the fabric should be replaced immediately.
Accumulated sediments should be removed from the fence base when the sediment reaches one-
third to halfway up the height of the fence. Sediment removal should occur more frequently if
accumulated sediment is creating a noticeable strain on the fabric, and there is the possibility that
the fence could fail from a sudden storm event.
Cost
There is a wide range of data on installation costs for silt fences. EPA estimates these costs at
approximately $6.00 per linear foot (USEPA 1992) while Southeastern Wisconsin Regional
Planning Commission (SWRPC) estimates unit costs between $2.30 and $4.50 per linear foot
(SWRPC 1991). Silt fences have an annual maintenance cost that is 100 percent of installation
cost (Brown and Schueler 1997). These values are significantly greater than that reported by R.S.
Means (2000), which indicates a 3-foot-tall silt fence installation cost between $0.68 and $0.92
per linear foot (for favorable and challenging installations). It should be noted that the R.S.
Means value covers just a single installation, without the expected costs of maintenance (e.g.,
removal of collected sediment). In addition, the type of silt fence fabric employed will also affect
the total installation costs.
7.2.3.2. Super Silt Fence
General Description
Super silt fence is a modification of a standard silt fence. The two central differences between
the standard silt fence and the super silt fence is that the super silt fence has toe that is buried
more deeply and the backing material is chain link fence held in place by steel postsa concept
that originated in Maryland. The Maryland super silt fence requires a Geotextile Class F fabric
over a chain link fence to intercept sediment-laden runoff from small drainage areas. The super
silt fence provides a barrier that can collect and hold debris and soil more effectively than a
standard silt fence, preventing material from entering critical areas. It is best used where the
installation of a dike would destroy sensitive areas, woods, and wetlands.
Applicability
Super silt fences can be used in the same conditions as a silt fence. Fences should follow the
contour of the land. Table 7-13 lists the distance a super silt fence should be from a slope to
ensure maximum effectiveness (MDE 1994).
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Table 7-13. Slope Lengths for Super Silt Fences
Slope
(%)
0-10
10-20
20-33
33-50
50+
Slope length
Minimum
Unlimited
200 feet
100 feet
100 feet
50 feet
Maximum
Unlimited
1,500 feet
1,000 feet
500 feet
250 feet
Design and Installation Criteria
As with the standard silt fence, design criteria are of two types, hydrologic design for a required
trapping of sediment and flow rate to pass the design storm and selection of appropriate
installation criteria such that the silt fence will perform as designed.
Hydrologic Design
Hydrologic design criteria are the same as the criteria for the standard silt fence.
Installation Criteria
The criteria used for the Maryland super silt fence indicate the following, although they have not
been tested with field data:
The fence should be placed as close to the contour as possible, with no section of the
silt fence exceeding a grade of 5 percent for a distance of more than 50 feet.
Fabric should be no more than 42 inches in height and should be held in place with a
6-foot chain link fence.
Fabric should be attached to the steel pole using wire ties or staples. Fabric should be
securely fastened to the chain link fence with ties spaced every 24 inches at the top
and midsection.
Fabric should be embedded into the ground at a minimum of 8 inches.
Edges of fabric should overlap by 6 inches.
Table 7-14 describes the physical properties of Geotextile class F fabric (MDE 1994).
Table 7-14. Minimum Requirements for
Super Silt Fence Geotextile Class F Fabric
Physical properties
Tension Strength
Tensile Modulus
Flow Rate
Filtering Efficiency
Requirements
50 pounds/inch
20 pounds/inch
0.3 gallon/ft2/minute
75%
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Effectiveness
Performance data have not been collected for super silt fences. The fences have been proposed
for locations within a sensitive watershed, or where site conditions prohibit the use of a standard
silt fence. However, until performance data are collected under field conditions, effectiveness is
speculative.
Limitations
Super silt fences are not as likely to fail structurally as are standard silt fences, but they are more
expensive than standard silt fences.
Maintenance
Maintenance requirements for super silt fences are generally the same as for standard silt fences.
Cost
The cost of the super silt fence is more than the standard silt fence because of deeper burial at the
toe and the cost of chain linked fencing. R.S. Means (2000) indicates a rental price of $10 to $11
per linear foot of chain linked fence for periods up to 1 year. Overall, rental is expected for most
construction site installation because rental rates are approximately half the price of permanent
chain link fencing.
7.2.3.3. Straw Bale Dike
General Description
The straw bale dike is a temporary measure used to trap sediment from small, sloping disturbed
areas. It is constructed of straw bales (not hay bales) wedged tightly together and placed along
the contour downslope of disturbed areas. The bales are placed in a shallow excavation, and the
upslope side is sealed with soil. Stakes are driven through the bales into the soil to help hold the
bales in place. The dike works by impounding water, which allows sediment to settle out in the
upslope area (Haan et al. 1994). Straw bale dikes are recommended for short duration application
and are usually effective for less than 3 months because of rapid decomposition (USDOT 1995).
Applicability
Straw bale dikes are generally placed at the toe of fills to provide for a broad shallow sediment
pool. The dikes should not be used in drainage areas with concentrated and high flows, in large
drainage areas, or in ditches and swales. The location of the straw bale dike should be fairly
level, at least 10 feet from the toe, and should follow the land contour. Table 7-15 lists the
distance a straw bale dike should be placed from a slope to ensure maximum effectiveness.
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Table 7-15. Maximum Land Slope and
Distances above a Straw Bale Dike
Land slope
(%)
Less than 2%
2%-5%
5%-10%
10%-20%
More than 20%
Maximum distance
above dam
(ft)
100
75
50
25
15
Source: USDOT 1995.
Design and Implementation Criteria
Hydrologic Design
Hydrologic design dictates the structure necessary to withstand a storm without causing damage
while trapping the required amount of sediment. Either a database or some type of model is
needed to find the appropriate design. Efforts to model the sediment trapping that occurs in straw
bale dikes have resulted in models that predict the settling in the ponded area upstream from the
dike (Barfield et al. 1996; Lindley et al. 1998). The results from model simulations show that
trapping depends primarily on the surface area of the impounded water and flow rate through the
filter. The models use a clear water slurry flow rate to predict discharge. It is anticipated, on the
basis of visual observations, that sediment will clog the straw bale barrier, reducing the slurry
flow rate. Thus, results from model studies to date are suspect and need to be modified to
account for the effect of clogging on flow rate.
Installation Criteria
The USDOT's BMP Manual and the Indiana BMP Manual call for bales to be
Anchored by driving two 36-inch long (minimum) steel rebars or 2 x 2-inch
hardwood stakes through each bale
Sized according to the standard bale size of 14 inches x 18 inches x 35 inches
Placed in an excavated trench at least 4 inches deep, a bale's width, and long enough
that the end bales are somewhat upslope of the sediment pool
Abutted tightly against each other
Sized so that impounded water depth should not exceed 1.5 feet
The USDOT BMP Manual does not require that straw bale dikes be designed; however, the
Indiana Manual limits the drainage area to one-quarter acre per 100 feet of dam and the total
drainage area draining to a straw bale dike to 2 acres.
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Effectiveness
The information on performance of straw bale dikes is very limited. In laboratory studies of bales
at varying orientations, Kouwen (1990) found that trapping efficiencies ranged from 60 to 100
percent. While field data on trapping have not been collected, bales deteriorate rapidly and need
to be replaced frequently. Because of these problems, the use of straw bale dikes as a perimeter
control is not recommended, except in special circumstances. Only 27 percent of erosion and
sediment control experts rated the straw bale dike as an effective erosion and sediment control
practice, although its use was still allowed in half of the communities surveyed (Brown and
Caraco 1997).
Limitations
Straw bale dikes should not be used as a diversion, in streams, in channels, or in areas with
concentrated flow. The bales are not recommended for paved areas because of the inability to
anchor the bales (IDNR 1992).
Care must be taken to ensure that the bales are not installed in an area where there is a
concentrated flow of runoff, in a drainage area that is too large, or on an excessive slope (IDNR
1992). Under these conditions, erosion around the end of the bales, overtopping and undercutting
of the bales, and bale collapsing and dislodging are likely to occur. Overtopping will also occur
if the storage capacity is underestimated and where provisions are not made for safe bypass of
storm flow (IDNR 1992). Undercutting will occur if the bales are not entrenched at least 4 inches
and backfilled with compacted soil or were not abutted or chinked properly. Straw bale dikes are
likely to collapse or dislodge if the bales are not adequately staked, or if too much sediment is
allowed to accumulate before cleanout (IDNR 1992).
Maintenance
For the straw bale dike to be most effective, it is important to replace deteriorated bales when
appropriate.
Cost
The cost of straw bale dikes is relatively low, making their use attractive. R.S. Means (2000)
indicates a staked straw bale unit cost of $2.61 per linear foot (Costs include materials, labor, and
equipment, with profit and overhead).
7.2.3.4. Sediment Trap
General Description
A sediment trap is a temporary control device used to intercept sediment-laden runoff and to trap
sediment to prevent or reduce off-site sedimentation. It is normally a more temporary type of
structure than a sediment pond and is constructed to control sediment on the construction area
during a selected phase of the construction operation. A sediment trap can be formed by
excavation and/or embankments constructed at designated locations accessible for cleanout. The
outlet for a sediment trap is typically a porous rock fill structure, which serves to detain the flow,
but a pipe structure can also be used. A temporary sediment trap can placed be in a drainageway,
at a storm drain inlet, or at other points of discharge from a disturbed area. They can be
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constructed independently or in conjunction with diversions and can be used in most drainage
situations to prevent excessive siltation of pipe structures (USEPA 1992).
Applicability
Sediment traps can simplify the stormwater control plan design process by trapping sediment at
specific spots at a construction site (USEPA 1992). They should be installed as early in the
construction process as possible and are primarily effective as a short-term solution to trapping
sediment from construction sites (WYDEQ 1999). Natural drainage patterns should be noted,
and sites where runoff from potential erosion can be directed into the traps should be selected.
Traps are most effective when capturing runoff from areas where 2 to 5 acres drain to one
location. Sediment traps should not be located in areas where their failure resulting from excess
runoff can lead to further erosive damage of the landscape. Alternative diversion pathways
should be designed to accommodate these potential overflows. Traps should be accessible for
clean-out and located so that they do not interfere with construction activity. In addition, the
traps are easily adaptable to most conditions.
Design and Implementation Criteria
Hydrologic Design
A sediment trap should be designed to maximize surface area and sediment settling. This will
increase the effectiveness of the trap and decrease the likeliness of backup during and after
periods of high runoff intensity. The design of a trap includes determining the storage volume,
surface area, dimensions of spillway or outlet, and elevations of embankment (USDOT 1995).
Sediment traps should be designed to meet a 2-year, 24-hour storm event, but the selection of a
return period varies among regulatory agencies (IDNR 1992).
Storage volume is created by a combination of excavation of land and construction of an
embankment to detain runoff (USDOT 1995). Trap storage volume and length of spillway are
determined as a function of the runoff volume and rate for the design storm. These parameters
will vary depending on return period rainfall and watershed hydrologic characteristics. Some
standards specify a storage volume per acre disturbed. For example, Smolen et al. (1988)
specified that approximate storage capacity of each trap should be at least 67 cubic yards per acre
disturbed draining into the trap, but more recent guidelines suggest 134 cubic yards per acre of
drainage area (VDCR 2001). Any national standard, however, should be based on runoff volume
and peak discharge to be generally applicable. Local regulations can translate this into applicable
volume and area standards.
A more important criterion than storage volume relates to sediment trapping. If a trapping
efficiency is specified, as in the case of South Carolina (SCDHEC 1995), it is necessary to
design for trapping efficiency. If a TSS or settleable solids effluent criterion is adopted
(SCDHEC 1995), settleable solids must be estimated. In both cases, a national standard should
address how to estimate trapping efficiency or settleable solids. Efforts to model the sediment
trapping that occurs in sediment traps have resulted in models that predict the settling in the
ponded area (Barfield et al. 1996; Lindley et al. 1998). The results from model simulations show
that trapping depends primarily on surface area of the impounded water and flow rate through
the rock fill outlet. In fact, the ratio of peak outflow rate to surface area is the best simple
predictor of trapping. The models use a modification of the Herrera and Felton (1991)
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relationship developed by Haan et al. (1994) to predict discharge rates. The predicted flow rates
do not take into account clogging that can occur in rock fill. No models or procedures are
available to estimate this clogging or its effect on flow criteria.
Design aids have also been developed for sediment traps, using simulations from the SEDEVICT
III (Barfield et al. 2001; Hayes et al. 2001). In the model, predictions are made of trapping
efficiency using the ratio of settling velocity for the dis of the eroded sediment, divided by the
ratio of discharge to ponded surface area. The design aid yields conservative estimates, but the
database used for generating the design aid is based on the assumption that flow rates are not
affected by clogging. This latter assumption is not likely to be a critical issue but should be
addressed in future research.
Installation Specifications
USDOT standards call for the embankment to be constructed of compacted earth, at a maximum
height of 5 feet (1.5 meters), a width of 4 to 5 feet (1.2 meters), and side slopes of 2:lor flatter.
These values might change as a result of local criteria and with changing soil characteristics.
Temporary vegetation should be applied to the embankment.
Two types of outlet structures are typically used for sediment traps, a rock outlet and a pipe
outlet. Spillways of large stones or aggregate are the most common type of outlet designed for
sediment traps. The crest of the spillway should be constructed 1 foot below the top of the
embankment and the spillway depth 1.5 feet below the top of the embankment. Weir length of
the spillway is determined on the basis of the contributing drainage area (Table 7-17) (USDOT
1995). The outlet apron should be a minimum of 5 feet long, and situated on level ground with a
filter fabric foundation to ensure exit velocity of drainage to receiving stream is nonerosive
(IDNR 1992).
The length of the rock outlet should be determined on the basis of peak discharge required and
rock characteristics, typically rock diameter. Flow rate calculations can be made with the
relationship of Herrera and Felton (1991) as modified by Haan et al. (1994). Alternatively, the
USDOT has specified the weir length for a given drainage area as shown in Table 7-16.
However, the values should be adjusted for each climatologic area to account for local
hydrologic and return period rainfall.
Table 7-16. Weir Length for Sediment Traps
Contributing drainage area
1
2
3
4
5
Weir length (ft)
4
5
6
10
12
Source: USDOT 1995.
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The pipe outlet, constructed of corrugated metal or PVC pipe riser, is an alternative to the rock
outlet. Pipe diameter is based on the peak discharge rate required. To obtain appropriate
freeboard, the top of pipe should be placed 1.5 feet below embankment elevation. Perforated
pipe is sometimes used. USDOT suggests perforations of 1-inch (25 mm) diameter holes or 0.5 x
6 inch (13 x 15 mm) slits in the upper two-thirds of the pipe; however, the discharge should be
calculated for this pipe specification to ensure that it matches the required peak discharge.
The pipe should be placed vertically and horizontally above wet storage elevation (USDOT
1995). Riprap should be used as an outlet protection and placed at the outlet of the barrel to
prevent scour from occurring (USDOT 1995). A stable channel should be provided to convey
discharge to the receiving channel (USDOT 1995).
Effectiveness
If it is assumed that the flow can be accurately controlled by the rock fill outlet, sediment traps
should operate as effectively as sediment basins, with trapping efficiencies reduced as a result of
smaller surface areas. The NURP study (USEPA 1993), Stahre and Urbonas (1990), and Haan, et
al., (1994), report that sediment basins effectively trapped sediment and chemicals as shown in
Table 7-17.
Table 7-17. Range of Measured Pollutant
Removal for Sediment Detention Basins
Item
Total suspended solids (TSS)
Total phosphorus (TP)
Nitrogen
Organic matter
Lead
Zinc
Hydrocarbons
Bacteria
Removable percentage
50°/c^70%
10%-20%
10°/c^20%
20%-40%
75°/c^90%
30%-60%
50°/c^70%
50%-90%
Source: Stahre and Urbonas 1990.
Information on the actual effectiveness of sediment traps is limited. The discussion should start
first with the flow hydraulics of the rock fill outlet typically employed as a principal spillway for
sediment traps. Procedures for estimating flow through rock fill have been developed by Herra
and Felton (1991) to estimate flow as a function of average rock diameter, standard deviation of
rock size, and flow length. If these parameters could be controlled in an actual situation, the flow
could be accurately predicted. However, given that standard construction practices consist of
end-dumping the rock fill in place, one would expect little correlation between design and
construction and the actual discharge and trapping efficiency would be expected to be
dramatically different from the design. This analysis does not mean that sediment traps are
ineffective, but that a given design could not be guaranteed to meet the effluent criteria, even
though the predictions indicate compliance. Sediment trapping efficiency is a function of surface
area and inflow rate (Smolen et al. 1988). Those traps that provide pools with large length-to-
width ratios have a greater chance of success.
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Sediment traps remove larger-sized sediment, primarily sized from silt to sands, by slowing
water velocity and allowing for sediment settling in ponded water (Haan et al. 1994). Although
sediment traps allow for settling of eroded soils, because of their short detention periods for
stormwater they typically do not remove fine particles such as silts and clays without chemical
treatment. Sediment settling ability is related to the square of the particle size; halving particle
sizes quadruples the time needed to achieve settlement (WYDEQ 1999). To increase overall
effectiveness, traps should be constructed in smaller areas with low slopes. Sediment traps are
typically designed to remove only sediment from surface water, but some non-sediment
pollutants are trapped as well (Haan et al. 1994).
Limitations
Common concerns associated with sediment traps are included in Table 7-18.
Table 7-18. Common Concerns Associated with Sediment Traps
Common concern
Inadequate spillway size
Omission or improper installation of geotextile
fabric
Low point in embankment caused by
inadequate compaction and settling
Stone outlet apron does not extend to stable
grade
Stone size too small or backslope too steep
Inadequate vegetative protection
Inadequate storage capacity
Contact slope between stone spillway and earth
embankment too steep
Outlet pipe installed in vertical side of trench
Corrugated tubing used as outlet pipe
Result
Results in overtopping of the dam and possible
failure of the structure
Results in piping under the sides or bottom of the
stone and outlet section
Results in overtopping and possible failure
Results in erosion below the dam
Results in stone displacement
Results in erosion of embankment
Results in a less than adequate settling time (can
also be caused by an insufficient amount of
sediment being removed from the basin
Results in piping failure
Results in piping failure of embankment
Results in crushed pipe and inadequate outlet
capacity
Source: IDNR 1992.
Maintenance
The primary maintenance consideration for temporary sediment traps is the removal of
accumulated sediment from the basin, which must be done periodically to ensure the continued
effectiveness of the sediment trap. Sediments should be removed when the basin reaches
approximately 50 percent sediment capacity.
A sediment trap should be inspected after each rainfall event to ensure that the trap is draining
properly. Inspectors should also check the structure for damage from erosion or piping. The
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depth of the spillway should be checked and maintained at a minimum of 1.5 feet below the low
point of the trap embankment.
Cost
The cost of installing temporary sediment traps ranges from $0.20 to $2.00 per cubic foot of
storage (about $1,100 per acre of drainage). EPA estimated the following costs for sediment
traps, which vary as a function of the volume of storage: $513 for 1,800 cubic yards, $1,670 for
3,600 cubic yards, and $2,660 for 5,400 cubic yards (USEPA 1993). Evaluation of a series of
more recent data sources (USEPA 2003) indicated that sediment traps have an average cost of
$0.30 per cubic foot of storage. In addition, it has been reported that a sediment trap has an
annual maintenance cost of 20 percent of installation cost (Brown and Schueler 1997).
7.2.3.5. Sediment Basin
General Description
A sediment basin is a stormwater detention structure formed by constructing a dam across a
drainageway or excavating a storage volume at other suitable locations and using it to intercept
sediment-laden runoff. Sediment basins are generally larger and more effective in retaining
sediment than temporary sediment traps and typically remain active throughout the construction
period. Jurisdictions that require post-development flow to be less than or equal to
predevelopment flow during construction could employ the designed detention facilities as a
temporary sediment basin during construction.
When sediment basins are designed properly, they can control sediment pollution through the
following functions (Faircloth 1999):
Sediment-laden runoff is caught to form an impoundment of water and create
conditions where sediment will settle to the bottom of the basin.
Treated runoff is released with less sediment concentration than when it entered the
basin.
Storage is provided for accumulated sediment, and resuspension by subsequent
storms is limited.
Applicability
Sediment basins should be located at a convenient concentration point for sediment-laden flows
(NCDNR 1988). Ideal sites are areas where natural topography allows a pond to be formed by
constructing a dam across a natural swale; such sites are preferred to those that require
excavation (Smolen et al. 1988).
Sediment basins are also applicable in drainage areas where it is anticipated that other erosion
controls, such as sediment traps, will not be sufficient to prevent off-site transport of sediment.
Choosing to construct a sediment basin with either an earthen embankment or a stone/rock dam
will depend on the materials available, location of the basin, and desired capacity for stormwater
runoff and settling of sediments.
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Rock dams are suitable where earthen embankments would be difficult to construct or where
riprap is readily available. Rock structures are also desirable where the top of the dam structure
is to be used as an emergency overflow outlet. These riprap dams are best for drainage areas of
less than 50 acres. Earthen damming structures are appropriate where failure of the dam will not
result in substantial damage or loss of property or life. If properly constructed, sediment basins
with earthen dams can handle stormwater runoff from drainage basins as large as 100 acres.
Design and Implementation Criteria
Hydrologic Design
A sediment basin can be constructed by excavation or by erecting an earthen embankment across
a low area or drainage swale. Sediment basins can be designed to drain completely during dry
periods, or they can be constructed so that a shallow, permanent pool of water remains between
storm events. Depending on the size of the basin constructed, the basin might be subject to
additional regulation, particularly state and federal regulations related to dam safety.
Sediment basins can be used for any size watershed, but USDOT recommends a drainage area
range of 5 to 100 acres (USDOT 1995). Components of a sediment basin that must be considered
in the hydrologic design include the following (Haan et al. 1994):
A sediment storage volume sized to contain the sediment trapped during the life of
the structure or between cleanouts
A permanent pool volume (if included) above the sediment storage to protect trapped
sediment and prevent resuspension as well as providing a first flush of discharge that
has been subjected to an extended detention period
A detention volume that contains storm runoff for a period sufficient to trap the
necessary quantity of suspended solids
A principal spillway that can be a drop-inlet pipe and barrel, a trickle tube, or other
type of controlled release structure
An emergency spillway that is designed to handle excessive runoff from the rarer
events and prevent overtopping
The following recommended procedures for conducting the hydrologic design are summarized
from Haan et al. (1994).
Sediment Storage Volume. This volume should be sufficient to store the sediment trapped
during the life of the structure or between cleanouts. Sediment storage volume can be calculated
on the basis of sediment yield using relationships such as the RUSLE with an appropriate
delivery ratio (Renard et al. 1994) or a computer model such as SEDIMOT III (Barfield et al.
1996) or SEDCAD (Warner et al. 1999). Many design specifications, however, base the
sediment storage volume on a volume per acre disturbed. For example, Pennsylvania specifies a
sediment storage volume of 1,000 cubic feet per acre drained (see DCN 43050, Pennsylvania
Erosion and Sediment Pollution Control Program Manual). This volume is highly site-specific,
depending on rainfall distributions, soil types, and construction techniques.
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Permanent Pool Volume. Providing a first flush of discharge that has been subjected to an
extended detention period can help to minimize degradation of water quality and justify some
permanent pool. The recommended capacity of the permanent pool varies with the regulatory
agency. USDOT, for example, recommends 67 cubic yards per acre (126 m3/ha) (USDOT 1995).
This standard has been adopted by many states as well. If an effluent criterion such as allowable
peak TSS or peak settleable solids is used, the final design of both permanent pool and detention
volume should be selected only after using a computer model to predict the expected peak
effluent concentrations.
Detention Volume. Storm runoff must be contained for a period of time sufficient to trap the
necessary quantity of suspended solids. Because inflow is occurring simultaneously with outflow,
the detention time for each plug of flow is different and should be considered individually. The
size of the detention volume, as stated above, should also be developed in concert with determining
the size of the permanent pool volume as well as the size of the principal spillway. When effluent
TSS and settleable solids criteria are used, the size of the detention volume and permanent pool
volume should be determined through a computer model calculation of expected effluent
concentrations for a given design. The return period used to size the detention volume depends on
the regulatory agency, but a return period of 10 years is typical for sediment basins that eventually
become stormwater detention ponds (i.e., are used to limit future flooding due to stormwater).
EPA's review of state construction site regulations found the majority of states specify detention
volume in terms of cubic feet per acre that drains to the sediment basin. State design values range
between 1,800 and 5,400 cubic feet per acre, with 3,600 cubic feet per acre or expected runoff
from the local 2-year, 24-hour storm event as the typical value.
Principal Spillway. The principal spillway is a hydraulic outlet structure sized to provide the
appropriate outflow rate to meet the effluent or trapping efficiency criteria. The principal
spillway should have a dewatering device that slowly releases water contained in the detention
storage over an extended period of time and at a rate determined to trap the required amount of
sediment and/or provide for the appropriate effluent concentration in the design storm. The more
common outlet structures are the drop-inlet structure and the trickle tube. Sizing of the principal
spillway should follow standard design procedures with respect to hydrology and sediment
considerations, but sizing the structure to simply pass the design storm is inappropriate and will
not result in meeting an effluent or trapping efficiency standard. The size to be used in a given
structure should be determined on the basis of the effluent or trapping efficiency standard being
targeted and site-specific hydrologic and soil conditions. Appropriate design will require the use
of a computer model such as SEDIMOT III (Barfield et al. 1996) or design aids such as those
developed for South Carolina (Hayes and Barfield 1995). In general, the design is developed to
maximize surface area, which will minimize peak discharge. Because failure of the dam could
result in downstream damage, the design should be done and certified by a licensed engineer
with expertise in hydrologic computation.
It has been proposed that a surface skimmer made of PVC, aluminum, or stainless steel and
designed to prevent trash from clogging can also be used to replace conventional principal
spillways. The skimmer puts the basin drain just below the water surface, allowing for a constant
head rather than variable head from the bottom. It is proposed that the skimmer allows water to
be released from the top of the basin, which would be the cleanest water, and that the skimmer
properly regulates the filling and draining of the basin (Faircloth 1999). The skimmer floats on
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the surface of the basin and rises as water in the basin rises during a storm. After the storm, the
skimmer slowly releases water from the basin. As the basin drains, the skimmer settles to the
bottom, draining the entire pool except for a pool directly under the skimmer. The skimmer can
be attached directly to an outlet pipe that drains through the dam or can be attached to an outlet
pipe through a riser. A single hole placed just above the sediment cleanout level can also dewater
the basin slowly.
Emergency Spillway. Because overtopping of the dam can cause failure and downstream damage,
an emergency spillway is necessary to handle excessive runoff from the larger, less frequent events
and prevent overtopping. The design storm for the emergency spillway will depend on the hazard
classification of the sediment basin. Typical return periods vary between 25 and 100 years, with 25
years recommended by USDOT. Sizing of the emergency spillway is typically accomplished to
simply transmit the rare event without eroding the base of the spillway. Procedures for making the
hydrologic and hydraulic computations are summarized in Haan et al. (1994). Again, because
failure of the dam could result in downstream damage, the design should be done and certified by a
licensed engineer with expertise in hydrologic computation.
Installation Criteria
The embankment for permanent sediment basins should be designed using standard geotechnical
construction techniques. The fill is typically constructed of earthen fill material placed and
compacted in continuous layers over the entire length of the fill. USDOT recommends 6- to 8-
inch layers (USDOT 1995). The embankment should be stabilized with vegetation after
construction of the basin. A cutoff trench should be excavated along the centerline of the dam to
prevent excessive seepage beneath the dam and be sized using standard geotechnical
computations. USDOT recommends that a minimum depth of the cutoff trench should be
approximately 2 feet (600 mm), the height should be to the riser crest elevation, the minimum
bottom width should be 4 feet (1.2 m) or wide enough for compaction equipment, and slopes
should be no steeper than 1:1.
Sediment basins can also be constructed with rock dams in a design that is similar to a sediment
basin with an earthen embankment. It is important to remember that rock fill is highly
heterogeneous and that flow rates calculated with any available procedure are not likely to match
those that will actually occur. Because sediment trapping is inversely proportional to flow rate,
the trapping efficiency will be affected significantly. No data are available to determine the
variability of rock fill in actual installations so that confidence intervals can be placed on
predicted flow rates. Such data should be collected and the confidence intervals calculated before
recommending the use of rock dams as outlets on any structures other than sediment traps.
Effectiveness
The effectiveness of a sediment basin depends primarily on the sediment particle size and the
ratio of basin surface area to inflow rate (Smolen et al. 1988; Haan et al. 1994). Basins with a
large surface area-to-volume ratio will be most effective. Studies by Barfield and Clar (1985)
showed that a surface area-to-peak discharge ratio of 0.01 acre per cubic foot would trap more
than 75 percent of the sediment coming from the Coastal Plain and Piedmont regions in
Maryland. This efficiency might vary for other regions of the country and should not be used as a
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national standard. Studies by Hayes et al. (1984) and Stevens et al. (2001), however, show that
similar relationships can be developed for other locations.
Laboratory data collected on pilot-scale facilities are available on the trapping efficiency of
sediment basins, effluent concentrations, dead storage and flow patterns, and the effects of
chemical flocculants on sediment trapping (Tapp et al. 1981; Wilson and Barfield 1984; Griffin
et al. 1985; Jarrett 1999; Ward et al. 1977, 1979). In general, the laboratory studies show that
pilot-scale ponds can be expected to trap 70 to 90 percent of sediment, depending on the
sediment characteristics, pond volume, and flow rate. The trapping efficiency and effluent
concentration are, in general, related to the overflow rate and can be reasonably well predicted
using a plug flow model (Ward et al. 1977, 1979) and a Continuously Stirred Tank Reactor
(CSTR) model (Wilson et al. 1982; Wilson et al. 1984). Extensive field-scale data are available
on long-term trapping efficiency in stormwater detention basins in which the annual trapping
efficiency is related to the annual capacity inflow ratio of the basin. These structures are not
representative of those used for sediment ponds but would be representative of those used for
regional detention. A more limited database is available on single storm sediment trapping in the
larger structures (Ward, et al. 1979) and on a field laboratory structure at Pennsylvania State
University (Jarret et al. 1999).
For maximum trap efficiency, Smolen et al. (1988) recommend the following:
Allow the largest surface area possible, maximize the length-to-width ratio of the
basin to prevent short circuiting, and ensure use of the entire design settling area.
Locate inlets for the basin at the maximum distance from the principal spillway
outlet.
Allow the maximum reasonable time to detain water before dewatering the basin.
Reduce the inflow rate into the basin and divert all sediment-free runoff.
Jarett (1999) has shown that the smaller the depth of the basin, the more sediment is discharged.
A 0.15-meter-deep (0.49-foot-deep) basin lost twice as much sediment as a 0.46-meter-deep
(1.5-foot-deep) basin. Jarrett also found that the performance of a sediment basin will increase
with the use of a skimmer in the principal spillway. The sediment discharged was 1.8 times
greater with only a perforated riser than with a skimmer in the principal spillway. In addition,
increasing the dewatering time, which will allow for more sediment deposition, decreases the
sediment loss from the basin (Jarett 1999).
Limitations
Neither a sediment basin with an earthen embankment nor a rock dam should be used in areas of
continuously running water (live streams). The use of sediment basins is not intended for areas
where failure of the earthen or rock dam will result in loss of life, damage to homes or other
buildings, or interference with the use of public roads or utilities.
Because sediment basins are usually temporary structures, they are often designed poorly and
rarely receive adequate attention and maintenance. As a result, these basins will not achieve the
function for which they were designed, especially when conventional outlets cannot properly
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meter outflow to create an impoundment, thus allowing rapid release of sediment-laden water
from the bottom of the basin to escape (Faircloth 1999).
Common concerns associated with sediment basins are included in Table 7-19.
Table 7-19. Common Concerns Associated with Sediment Basins
Common concern
Improper compaction, omission of anti-seep
collar, leaking pipe joints, or use of unsuitable soil
Inadequate vegetation or improper grading and
sloping
Inadequate compaction or use of unsuitable soil
Steep side slopes
Inadequate outlet protection
Basin not located properly for access
Sediment not properly removed
Lack of anti -flotation
Principal and emergency spillway on design plans
Gravel clogging the dewatering system
Principal spillway too small
Result
Results in piping failure along conduit
Results in erosion of spillway or embankment
slopes
Results in slumping or settling of embankment
Results in bank failure due to slumping
Results in erosion and caving below principal
spillway
Results in difficult, ineffective, and costly
maintenance
Results in inadequate storage capacity and
potential re suspension
Results in the riser and barrel being blocked
with debris
Results in improper disposal of accumulated
sediment
Results in safety or health hazard from pond
water
Results in frequent operation of emergency
spillway and increased erosion potential
Source: IDNR 1992.
Maintenance
Routine inspection and maintenance of sediment basins is essential to their continued
effectiveness. Basins should be inspected after each storm event to ensure proper drainage from
the collection pool and determine the need for structural repairs. Erosion from the earthen
embankment or stones moved from rock dams should be repaired or replaced immediately.
Sediment basins must be located in an area that is easily accessible to maintenance crews for
removal of accumulated sediment. Sediment should be removed from the basin when its storage
capacity has reached approximately 50 percent. Trash and debris from around dewatering
devices should be removed promptly after rainfall events.
Cost
If constructing a sediment basin with less than 50,000 cubic feet of storage space, the cost of
installing the basin ranges from $0.20 to $1.30 per cubic foot of storage (approximately $1,100
per acre of drainage) with an average cost of approximately $0.60 per cubic foot of storage
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(USEPA 1993). If constructing a sediment basin with more than 50,000 cubic feet of storage
space, the cost of installing the basin ranges from $0.10 to $0.40 per cubic foot of storage
(approximately $550 per acre of drainage) with an average cost of approximately $0.30 per cubic
foot of storage (USEPA 1993). A review of state highway project bids and county bonding
estimates conducted in 2003 confirmed this value of $0.30 per cubic foot (USEPA 2003). Annual
maintenance costs are 25 percent of installation costs (Brown and Schueler 1997).
R.S. Means (2000) suggests the cost to remove the eroded sediment collected in a small basin
during construction is approximately $4 per cubic yard (this value includes a 100 percent
surcharge for wet excavation). Disposal of material on-site will result in an additional cost that
can be computed only from site-specific conditions. The cheapest management of dredged
material is application to land areas adjacent to the basin followed with application of a
vegetative cover.
7.2.4. OTHER CONTROL PRACTICES
7.2.4.1. Stone Outlet Structure
Description
A stone outlet structure is a temporary stone dike installed in conjunction with and as a part of an
earth dike. The purpose of the stone outlet structure is to impound sediment-laden runoff,
provide a protected outlet for an earth dike, provide for diffusion of concentrated flow, and allow
the area behind the dike to dewater slowly. The stone outlet structure can extend across the end
of the channel behind the dike or be placed in the dike itself. In some cases, more than one stone
outlet structure can be placed in a dike.
Applicability
Stone outlet structures apply to any point of discharge where there is a need to discharge runoff
at a protected outlet or to diffuse concentrated flow for the duration of the period of construction.
The drainage area to this practice is typically limited to one-half acre or less to prevent excessive
flow rates. The stone outlet structure should be located so as to discharge onto an already
stabilized area or into a stable watercourse. Stabilization should consist of complete vegetative
cover and paving that are sufficiently established to be erosion resistant.
Design and Installation Criteria
Design criteria are of two types, hydrologic design for a required trapping of sediment and/or
flow rate to pass the design storm; and selection of appropriate installation criteria such that the
stone outlet will perform as designed.
Hydrologic Design
The hydrologic design should be based on the design storm and standard hydraulic calculations.
It should include the following considerations:
Design rainfall and design storm. The design storm should be specified by the
regulatory authority. Typically a return period of 2 to 5 years is used. Runoff rates
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should be calculated with standard hydrologic procedures as allowed by the
regulatory authority.
Drainage area. The drainage area to this structure is typically limited to less than half
an acre to ensure that the flow rates are not excessive.
Length of crest and height of stone fill. The crest length and height of stone fill
should be of sufficient size to transmit the design storm without overtopping. The
volume of water stored behind the dike can be estimated, but would require routing
the storm flow in the design storm. Flow through the stone outlet can be calculated
using the relationships of Herrera and Felton (1991) as modified by Haan et al.
(1994). The height of the fill should be small enough to prevent excessive flow
velocities through the stone fill and prevent undercutting.
Outlet stabilization. The discharge from the stone outlet should be stabilized with
vegetated waterways or riprap until the flow reaches a stable channel. Design of the
stabilized outlet should follow procedures presented earlier.
Installation Criteria Specifications
A stone outlet structure should conform to the following specifications:
The outlet should be composed of 2- to 3-inch stone or recycled concrete, but clean
gravel can be used if stone is not available.
The crest of the stone dike should be at least 6 inches lower than the lowest elevation
of the top of the earth dike and should be level.
The stone outlet structure should be embedded into the soil a minimum of 4 inches.
The minimum length of the crest of the stone outlet structure should be 6 feet.
The baffle board should extend 1 foot into the dike and 4 inches into the ground and
be staked in place.
The drainage area to this structure should be less than half an acre.
7.2.4.2. Rock Outlet Protection
Description
Rock outlet structures are rocks that are placed at the outfall of channels or culverts to reduce the
velocity of flow in the receiving channel to nonerosive rates.
Applicability
This practice applies where discharge velocities and energies at the outlets of culverts are
sufficient to erode the next downstream reach and is applicable to outlets of all types such as
sediment basins, stormwater management ponds, and road culverts.
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Design and Installation Criteria
Hydrologic Design
Hydrologic design consists primarily of selecting the design runoff rate and sizing outlet
protection. Standard hydrologic calculations should be used with an appropriate return period
storm for the outlet being protected (typical return periods range from 2 to 10 years).
The process for sizing outlet protection involves selecting the type and geometry of the outlet
protection and the size of the rock lining. The outlet protection could consist of a plunge pool
(scour hole), an apron-type arrangement, or an energy dissipation basin (Haan et al. 1994). The
design of each differs. Plunge pools are typically used for outlet pipes that are elevated above the
water surface. Aprons are used for other types of outlets. Plunge pool geometry is based on the
flow rate, pipe size and slope, tailwater depth, and size of the riprap lining (Haan et al. 1994).
Apron dimensions are determined by the ratio of the tailwater depth to pipe diameter (Haan et al.
1994). Energy dissipation basins are used as an alternative to the plunge pool. Dimensions are a
function of the brink depth in the pipe at the design flow, pipe diameter, and size of riprap (Haan
et al. 1994). The size of the rock lining is a function of the discharge, pipe size, tailwater depth,
and geometry selected. Details on sizing the rock are given in Haan et al. (1994).
The design method presented here applies to the sizing of rock riprap and gabions to protect a
downstream area. It does not apply to rock lining of channels or streams. The design of rock
outlet protection depends entirely on the location. Pipe outlets at the top of cuts or on slopes
steeper than 10 percent cannot be protected by rock aprons or riprap sections due to
reconcentration of flows and high velocities encountered after the flow leaves the apron.
Installation Criteria
The following criteria should be considered:
Bottom grade: The outlet protection apron should be constructed with zero slope
along its length. There should be no obstruction at the end of the apron. The elevation
of the downstream end of the apron should be equal to the elevation of the receiving
channel or adjacent ground.
Alignment: The outer protection apron should be located so that there are no beds in
the horizontal alignment.
Materials: The outlet protection can be accomplished using rock riprap or gabions.
Riprap should be composed of a well-graded mixture of stone sized so that 50 percent
of the pieces, by weight, should be larger than the size determined using charts. The
minimum dso size to be used should be 9 inches. A well-graded mixture is defined as
a mixture composed primarily of larger stone sizes but with a sufficient mixture of
other sizes to fill the smaller voids between the stones. The diameter of the largest
stone in such a mixture should be 2 times the size selected in Table 7-20 (MDE
1994).
Thickness: Riprap specification values are summarized in Table 7-20.
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Table 7-20. Riprap Sizes and Thicknesses
Class I
Class II
Class III
D50
(inches)
9.5
16
23
DIOO
(inches)
15
24
34
Thickness
(inches)
19
32
46
Source: USDOT 1995
Stone Quality: Stone for riprap should consist of field stone or rough-hewn quarry
stone. The stone should be hard and angular and of a quality that will not disintegrate
on exposure to water or weathering. The specific gravity of the individual stones
should be at least 2.5. Recycled concrete equivalent can be used, provided it has a
density of at least 150 pounds per cubic foot and does not have any exposed steel or
reinforcing bars.
Filters: A layer of material placed between the riprap and the underlying soil surface
can prevent soil movement into and through the riprap to prevent piping, reduce uplift
pressure, and collect water. Riprap should have a filter placed under it in all cases. A
filter can be of two general forms: a gravel layer or a geotextile.
Gabions: Gabion baskets can be used as rock outlet protection, provided they are
made of hexagonal triple twist mesh with heavily galvanized steel wire. The
maximum lined dimension of the mesh opening should not exceed 4.5 inches. The
area of the mesh opening should not exceed 10 square inches. Gabions should be
fabricated in such a manner that the sides, ends, and lid can be assembled at the
construction site into a rectangular basket of the specified sizes.
Gabions should be of a single unit construction and should be installed according to
the manufacturer's specifications. Foundation conditions should be the same as for
placing rock riprap. Geotextiles should be placed under all gabions, and gabions must
be keyed in to prevent undermining of the main gabion structure.
The subgrade for the filter, riprap, or gabion should be prepared to the required lines
and grades. Any fill required in the subgrade should be compacted to a density of
approximately that of the surrounding undisturbed material.
The rock or gravel should conform to the specified grading limits when installed in
the riprap or filter, respectively.
Geotextiles should be protected from punching, cutting, or tearing. Any damage other
than occasional small holes should be repaired by placing another piece of geotextile
fabric over the damaged part or by completely replacing the geotextile fabric. All
overlaps, whether for repairs or for joining two pieces of geotextile fabric, should be a
minimum of 1 foot in length.
Stone for the riprap or gabion outlets can be placed by equipment. They should be
constructed to the full course thickness in one operation and in such a manner as to
avoid displacement of underlying materials. Care should be taken to ensure that the
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stone is not placed so that rolling would cause segregation of stone by size, i.e., the
stone for riprap or gabion outlets should be delivered and placed in a manner that will
ensure that it is reasonably homogeneous, with smaller stones filling the voids
between larger stones. Riprap must be placed so as to prevent damage to the filter
blanket or geotextile fabric. Hand placement will be required to the extent necessary
to prevent damage to the permanent works.
Stone should be placed so that it blends in with the existing ground and the depth to
the stone surface is sufficient to transmit the flow without spilling over onto the
unprotected surface.
Effectiveness
There is no information on the effectiveness of rock outlet structures.
Limitations
Common problems with rock outlet structures include the following:
If the foundation is not excavated deeply or wide enough, the flow cross-section
could be restricted, resulting in erosion around the apron and scour holes at the outlet.
Also, the riprap apron should be placed on a suitable foundation to prevent
downstream erosion.
If the riprap that is installed is smaller than specified, rock displacement might result;
selectively grouting over the rock materials could stabilize the installation.
If the riprap is not extended enough to reach a stable section of the channel,
downstream erosion could result.
If a filter is not installed under the riprap, stone displacement and erosion of the
foundation might result.
Maintenance
Once a riprap outlet has been installed, the maintenance needs are very low. It should be
inspected after high flows to see if scour has occurred beneath the riprap, if flows have occurred
outside the boundaries of the riprap and caused scour, or if any stones have been dislodged.
Repairs should be made immediately.
Cost
R.S. Means (2000) indicates machine-placed riprap costs of approximately $40 per cubic yard.
For a riprap maximum size between 15 and 24 inches, a cubic yard of riprap will cover between
13.5 and 17 square feet at channel bed (assuming depth of riprap as given in Table 5-22). This
suggests that riprap lining will be between $21 and $27 per square foot of outlet (includes
materials, labor, and equipment, with overhead and profit). R.S. Means (2000) provides a cost
range for gabions ($2.80 to $9 per square foot of coverage) for stone fill depths of 6 to 36 inches,
respectively. These costs include all costs of materials, labor, and installation.
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7.2.4.3. Sump Pit
Description
A sump pit is a temporary pit from which pumping is conducted to remove excess water while
minimizing sedimentation. The purpose of the sump pit is to filter water being pumped to reduce
sedimentation to receiving streams.
Applicability
Sump pits are constructed when water collects and must be pumped away during excavating,
cofferdam dewatering, maintenance or removal of sediment traps and basins, or other uses as
applicable, such as for concrete wash out.
Design and Installation Criteria
Hydrologic Design
The only hydrologic calculation is determining the expected flow rate and volume to be handled.
This should follow standard hydrologic computational procedures based on design rainfall,
surface and soil conditions, and the size of the pump.
Installation Criteria and Specifications
The number of sump pits and their locations should be determined by the designer and included
on the plans. Contractors can relocate sump pits to optimize use, but discharge location changes
should be coordinated with inspectors.
A perforated, vertical standpipe should be wrapped with 1/2-inch hardware cloth and geotextiles
and then placed in the center of an excavated pit, which is then backfilled with filter material
ranging from clean gravel to stone. Water is then pumped from the center of the standpipe to a
suitable discharge area such as into a sediment trap, sediment basin, or stabilized area.
A sump pit should conform to the following specifications:
Pit dimensions are variable, with the minimum diameter being twice the diameter of
the standpipe.
The standpipe should be constructed by perforating a 12- to 36-inch diameter pipe,
then wrapping it with 1/2-inch hardware cloth and geotextiles. The perforations
should be 1/2-inch slits or 1-inch diameter holes placed 6 inches on center.
The standpipe should extend 12 to 18 inches above the lip of the pit or riser crest
elevation (basin dewatering), and filter material should extend 3 inches minimum
above the anticipated standing water level.
Effectiveness
There is no information on the effectiveness of the sump pit.
Limitations
The sump pit must be properly maintained and pumped regularly to avoid clogging.
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Maintenance
To maintain, sump pits must be removed and reconstructed when water can no longer be pumped
out of the standpipe.
Cost
R.S. Means (2000) provides information appropriate for assessing a wide range of dewatering
scenarios (i.e., different sump sizes, dewatering durations, and discharge conditions). In general,
installing earthen sump pits are listed as costing approximately $1.50 per cubic foot of sump
volume. Piping to and away from the sump ranges from $30 to $60 per linear foot. Pump rentals
and operation range between $150 and $500 per day of pumping, depending on the rate of
dewatering. All costs include materials, labor, and equipment, with overhead and profit.
7.2.4.4. Sediment Tank
Description
A sediment tank is a compartmented container through which sediment-laden water is pumped to
trap and retain sediment before pumping the water to drainageways, adjoining properties, and
rights-of-way below the sediment tank site.
Applicability
A sediment tank should be used on sites where excavations are deep and space is limited, such as
urban construction, where direct discharge of sediment-laden water to streams and storm
drainage systems should be avoided.
Design and Installation Criteria
The location of sediment tanks should facilitate easy cleanout and disposal of the trapped
sediment to minimize interference with construction activities and pedestrian traffic. The tank
size should be determined according to the storage volume of the sediment tank, with 1 cubic
foot of storage for each gallon per minute of pump discharge capacity.
Effectiveness
There is no information on the effectiveness of sediment tanks.
Limitations
The sediment tank does not provide any natural infiltration; thus, the trapped sediment and
stormwater must be disposed of properly.
Maintenance
To facilitate maintenance of sediment tanks, they need to be located with easy access for regular
pump out. The rate at which a tank is pumped depends on site-specific considerations such as
rainfall and sediment loads to the system. Regular inspections will help to determine pump out
frequency and prevent overloading and failure of the system.
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Cost
There is no information on the cost of sediment tanks.
7.2.4.5. Stabilized Construction Entrance
Description
The purpose of stabilizing entrances to a construction site is to minimize the amount of sediment
leaving the area as mud attached to tires. Installing a pad of gravel over filter cloth where
construction traffic leaves a site can help stabilize a construction entrance. As a vehicle drives
over the gravel pad, mud and other sediments are removed from the vehicle's wheels (sometimes
by washing) and off-site transport of sediment is reduced. The gravel pad also reduces erosion
and rutting on the soil beneath the stabilization structure. The fabric reduces the amount of
rutting caused by vehicle tires by spreading the vehicle's weight over a larger soil area than just
the tire width. The filter fabric also separates the gravel from the soil below, preventing the
gravel from being ground into the soil.
Applicability
Stabilized construction entrances typically are installed at locations where construction traffic
leaves or enters an existing paved road. However, the applicability of site entrance stabilization
should be extended to any roadway or entrance where vehicles will access or leave the site.
From a public relations point of view, stabilizing construction site entrances can be a worthwhile
exercise. If the site entrance is the most publicly noticeable part of a construction site, stabilized
entrances can improve the appearance to passersby and improve public perception of the
construction project by reducing the amount of mud tracked onto adjacent streets.
Design and Installation Considerations
Hydrologic Design
Not applicable.
Installation Criteria and Specifications
All entrances to a site should be stabilized before construction begins and further disturbance of
the site area occurs. The stabilized site entrances should be long enough and wide enough so that
the largest construction vehicle that will enter the site will fit in the entrance with room to spare.
If many vehicles are expected to use an entrance in any one day, the site entrance should be wide
enough for the passage of two vehicles at the same time with room on either side of each vehicle.
For optimum effectiveness, a rock construction entrance should be at least 50 feet long and at
least 10 to 12 feet wide (USEPA 1992). If a site entrance leads to a paved road, the end of
entrance should be flared (made wider as in the shape of a funnel) so that long vehicles do not go
off the stabilized area when turning onto or off of the paved roadway.
If a construction site entrance crosses a stream, swale, roadside channel, or other depression, a
bridge or culvert should be provided to prevent erosion from unprotected banks.
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Stone and gravel used to stabilize the construction site entrance should be large enough so that
nothing is carried off-site with vehicle traffic. In addition, sharp-edged stone should be avoided
to reduce the possibility of puncturing vehicle tires. Stone or gravel should be installed at a depth
of at least 6 inches for the entire length and width of the stabilized construction entrance.
Effectiveness
Stabilizing construction entrances to prevent sediment transport off-site is effective only if all
entrances to the site are stabilized and maintained. Also, stabilizing construction site entrances
might not be very effective unless a wash rack is installed and routinely used (Corish 1995),
although this can be problematic for sites with multiple entrances that have high vehicle traffic.
Limitations
Although stabilizing a construction entrance is a good way to help reduce the amount of
sediment leaving a site, some sediment can still be deposited from vehicle tires onto paved
surfaces. To further reduce the chance that these sediments will pollute stormwater runoff,
sweeping of the paved area adjacent to the stabilized entrance is recommended.
For sites using wash stations, a reliable water source to wash vehicles before leaving the site
might not be initially available. In such a case, water might have to be trucked to the site at an
additional cost. Discharge from the wash station should be directed to an appropriate sediment
control structure.
Maintenance
Stabilization of site entrances should be maintained until the remainder of the construction site
has been fully stabilized. Stone and gravel might need to be periodically added to each stabilized
construction site entrance to maintain its effectiveness. Soil that is tracked off-site should be
swept up immediately and disposed of properly.
For sites with wash racks at each site entrance, sediment traps will have to be constructed and
maintained for the life of the project. Maintenance will entail the periodic removal of sediment
from the traps to ensure their continued effectiveness.
Cost
Without a wash rack, construction site entrance stabilization costs range from $1,000 to $4,000.
On average, the initial construction cost is approximately $2,000 per entrance. When
maintenance costs are included, the average total annual cost for a 2-year period is
approximately $1,500. If a wash rack is included in the construction site entrance stabilization,
the initial construction costs range from $1,000 to $5,000, with an average initial cost of $3,000
per entrance. Total annual cost, including maintenance for an estimated 2-year life span, is
approximately $2,200 per year (USEPA 1993).
7.2.4.6. Land Grading
Description
Land grading involves reshaping the ground surface to planned grades as determined by an
engineering survey, evaluation, and layout. Land grading provides more suitable topography for
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buildings, facilities, and other land uses and helps to control surface runoff, soil erosion, and
sedimentation both during and after construction.
Applicability
Land grading is applicable to sites with steep topography or easily erodible soils because it
stabilizes slopes and decreases runoff velocity. Grading activities should maintain existing
drainage patterns as much as possible.
Design and Installation Criteria
Before grading activities begin, decisions should be made regarding the steepness of cut-and-fill
slopes and how the slopes will be protected from runoff, stabilized, and maintained. A grading
plan should be prepared that establishes which areas of the site will be graded, how drainage
patterns will be directed, and how runoff velocities will affect receiving waters. The grading plan
also includes information regarding when earthwork will start and stop, establishes the degree
and length of finished slopes, and dictates where and how excess material will be disposed of (or
where borrow materials will be obtained if needed). Berms, diversions, and other stormwater
practices that require excavation and filling should also be incorporated into the grading plan.
One low-impact development technique that can be incorporated into a grading plan is site
fingerprinting. This involves clearing and grading only those areas necessary for building
activities and equipment traffic. Adhering to strict limits of clearing and grading helps to
maintain undisturbed temporary or permanent buffer zones in the grading operation and provides
a low-cost sediment control measure that will help reduce runoff and off-site sedimentation. The
lowest elevation of the site should remain undisturbed to provide a protected stormwater outlet
before storm drains or other construction outlets are installed.
Effectiveness
Land grading is an effective means of reducing steep slopes and stabilizing highly erodible soils
when implemented with stormwater management and erosion and sediment control practices in
mind. Land grading is not effective when drainage patterns are altered or when vegetated areas
on the perimeter of the site are destroyed.
Limitations
Construction sites are routinely graded to prepare a site for buildings and other structures.
Improper grading practices that disrupt natural stormwater patterns can lead to poor drainage,
high runoff velocities, and increased peak flows during storm events. Clearing and grading of the
entire site without vegetated buffers promotes off-site transport of sediments and other
pollutants. Grading plans should be designed with erosion and sediment control and stormwater
management goals in mind; grading crews should be carefully supervised to ensure that the plan
is implemented as intended.
Maintenance
All graded areas and supporting erosion and sediment control practices should be periodically
checked, especially after heavy rainfalls. All sediment should be promptly removed from
diversions or other stormwater conveyances. If washouts or breaks occur, they should be
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repaired immediately. Prompt maintenance of small-scale eroded areas is essential to prevent
these areas from becoming significant gullies.
Cost
Land grading is practiced at virtually all construction sitesadditional site planning to
incorporate stormwater and erosion and sediment controls in grading plans can require several
hours of planning by a certified engineer or landscape architect. Extra time might be required to
excavate diversions and construct berms, and fill materials might be needed to build up low-
lying areas or fill depressions.
Where grading is performed to manage on-site stormwater, R.S. Means (2000) suggests the cost
of fine grading, soil treatment, and grassing to be approximately $2 per square yard of earth
surface area. Shallow excavation/trenching (1 to 4 feet deep) with a backhoe in areas not
requiring dewatering can be performed for $4 to $5 per cubic yard of removed material. Larger
scale grading requires a site-specific assessment of an alternative grading apparatus and a
detailed fill/excavation material balance to retain as much soil on site as possible.
7.2.4.7. Temporary Access Waterway Crossing
Description
A temporary stream crossing is a structure erected to provide a safe and stable way for
construction vehicle traffic to cross a running watercourse. The primary purpose of such a
structure is to provide streambank stabilization, to reduce the risk of damaging the streambed or
channel, and to reduce the risk of sediment loading from construction traffic. A temporary stream
crossing could be a bridge, culvert, or ford.
Applicability
Temporary stream crossings are applicable wherever heavy construction equipment must be
moved from one side of a stream channel to the other or where lighter construction vehicles will
cross the stream a number of times during the construction period. In either case, an appropriate
method for ensuring the stability of the streambanks and preventing large-scale erosion is
necessary.
A bridge or culvert is the best choice for most temporary stream crossings. If properly designed,
each can support heavy loads, and materials used to construct most bridges and culverts can be
salvaged after they are removed. Fords are appropriate in steep areas subject to flash flooding,
where normal flow is shallow or intermittent across a wide channel. Fords should be used only
where stream crossings are expected to be infrequent.
Design and Installation Criteria
Because of the potential for stream degradation, flooding, and safety hazards, stream crossings
should be avoided on a construction site whenever possible. Consideration should be given to
alternative site access routes before arrangements are made to erect a temporary stream crossing.
If it is determined that a stream crossing is necessary, an area where the potential for erosion is
low should be selected. The stream crossing structure should be installed during a dry period if
possible to reduce sediment transport into the stream.
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If needed, over-stream bridges are generally the preferred temporary stream crossing structure.
The expected load and frequency of the stream crossing, however, will govern the selection of a
bridge as the correct choice for a temporary stream crossing. These types of temporary bridges
usually cause minimal disturbance to a stream's banks and cause the least obstruction to stream
flow and fish migration. They should be constructed only under the supervision and approval of
a qualified engineer.
As general guidelines for constructing temporary bridges, clearing and excavation of the stream
shores and bed should be kept to a minimum. Sufficient clearance should be provided for
floating objects to pass under the bridge. Abutments should be parallel to the stream and be
placed on stable banks. If the stream is less than 8 feet wide at the point where a crossing is
needed, no additional in-stream supports should be used. If the crossing is to extend across a
channel wider than 8 feet (as measured from the top of one bank to the other), the bridge should
be designed with one in-water support for each 8 feet of stream width.
A temporary bridge should be anchored by steel cable or chain on one side only to a stable
structure on shore. Examples of anchoring structures include trees with a large diameter, large
boulders, and steel anchors. By anchoring the bridge on one side only, there is a decreased risk of
causing a downstream blockage or flow diversion if a bridge is washed out.
When constructing a culvert, filter cloth should be used to cover the streambed and streambanks
to reduce settlement and improve the stability of the culvert structure. The filter cloth should
extend a minimum of 6 inches and a maximum of 1 foot beyond the end of the culvert and
bedding material. The culvert piping should not exceed 40 feet in length and should be of
sufficient diameter to allow for complete passage of flow during peak flow periods. The culvert
pipes should be covered with a minimum of 1 foot of aggregate. If multiple culverts are used, at
least 1 foot of aggregate should separate the pipes.
Fords should be constructed of stabilizing material such as large rocks.
Effectiveness
Both temporary bridges and culverts provide an adequate path for construction traffic crossing a
stream or watercourse.
Limitations
Bridges can be considered the greatest safety hazard of all temporary stream crossing structures
if not properly designed and constructed. Bridges can also prove to be more costly in terms of
repair costs and lost construction time if they wash out or collapse (Smolen et al. 1988).
The construction and removal of culverts are usually very disturbing to the surrounding area, and
erosion and downstream movement of sediments are often great. Culverts can also create
obstructions to flow in a stream and inhibit fish migration. Depending on their size, culverts can
be blocked by large debris and are therefore vulnerable to frequent blockage and washout.
If given a choice between building a bridge or a culvert as a temporary stream crossing, a bridge
is preferred because of the relative minimal disturbance to streambanks and the opportunity for
unimpeded flow through the channel. The approaches to fords often have high erosion potential.
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In addition, excavation of the streambed and approach to lay riprap or other stabilization material
causes major stream disturbance. Mud and other debris are transported directly into the stream
unless the crossing is used only during periods of low flow.
Maintenance
Temporary stream crossings should be inspected at least once a week and after all significant
rainfall events. If any structural damage is reported to a bridge or culvert, construction traffic
should be excluded until appropriate repairs are made. Streambank erosion should be repaired
immediately.
Fords should be inspected closely after major storm events to ensure that stabilization materials
remain in place. If the material has moved downstream during periods of peak flow, the lost
material should be replaced immediately.
Cost
In general, temporary bridges are more expensive to design and construct than culverts. Bridges
are also associated with higher maintenance and repair costs should they fail. Temporary
bridging costs vary as a function of the width of the bridge span and the amount of time the
bridge is installed. If the bridging is permanent, a mean cost of $50 per square foot for an 8-foot
wide steel arch bridge (no foundation costs included) can be used for conceptual cost estimation
(R.S. Means 2000). If rental bridging is employed, rates are probably on the order of 20 to 50
percent of the bridge (permanent) cost but will vary according to the rental duration and
mobilization distance.
7.2.4.8. Dust Control
General Description
Dust control measures are practices that help reduce ground surface and air movement of dust
from disturbed soil surfaces. Construction sites are good candidates for dust control measures
because land disturbance from clearing and excavation generates a large amount of soil
disturbance and open space for wind to pick up dust particles. To illustrate this point, research at
construction sites has established an average dust emission rate of 1.2 tons/acre/month for active
construction (WDEC 1992). These airborne particles pose a dual threat to the environment and
human health. First, dust can be carried off-site, thereby increasing soil loss from the
construction area and increasing the likelihood of sedimentation and water pollution. Second,
blowing dust particles can contribute to respiratory health problems and create an inhospitable
work environment.
Applicability
Dust control measures are applicable to any construction site where dust is created and there is
the potential for air and water pollution from dust traveling across the landscape or through the
air. Dust control measures are particularly important in arid or semiarid regions where soil can
become extremely dry and vulnerable to transport by high winds.
Also, dust control measures should be implemented on all construction sites where there will be
major soil disturbances or heavy construction activity, such as clearing, excavation, demolition,
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or excessive vehicle traffic. Earthmoving activities are the major source of dust from
construction sites, but traffic and general disturbances can also be major contributors (WDEC
1992).
The specific dust control measures implemented at a site will depend on the topography, land
cover, soil characteristics and amount of rainfall at the site.
Design and Installation Criteria
When designing a dust control plan for a site, the amount of soil exposed will dictate the quantity
of dust generation and transport. Therefore, construction sequencing and disturbing small areas
at one time can greatly reduce problematic dust from a site. If land must be disturbed, additional
temporary stabilization measures should be considered before disturbance.
A number of methods can be used to control dust from a site. The following is a brief list of
control measures and their design criteria. Not all control measures will be applicable to a given
site. The owner, operator, and contractors responsible for dust control should determine which
practices accommodate their needs on the basis of specific site and weather conditions.
Sprinkling/Irrigation: Sprinkling the ground surface with water until it is moist is an effective
dust control method for haul roads and other traffic routes (Smolen et al. 1988). This practice can
be applied to almost any site.
Vegetative Cover: In areas not expected to handle vehicle traffic, vegetative stabilization of
disturbed soil is often desirable. Vegetative cover provides protection to surface soils and slows
wind velocity at the ground surface, thus reducing the potential for dust to become airborne.
Mulch: Mulching can be a quick and effective means of dust control for a recently disturbed
area (Smolen et al. 1988).
Wind Breaks: Wind breaks are barriers (either natural or constructed) that reduce wind velocity
and therefore reduce the possibility of carrying suspended particles. Wind breaks can be trees or
shrubs left in place during site clearing or constructed barriers such as a wind fence, snow fence,
tarp curtain, hay bale, crate wall, or sediment wall (USEPA 1992).
Tillage: Deep tillage in large open areas brings soil clods to the surface where they rest on top of
dust, preventing it from becoming airborne.
Stone: Stone can be an effective dust deterrent for construction roads and entrances.
Spray-on Chemical Soil Treatments (palliatives): Examples of chemical adhesives include
anionic asphalt emulsion, latex emulsion, resin-water emulsions, and calcium chloride. Chemical
palliatives should be used only on mineral soils. When considering chemical application to
suppress dust, consideration should be taken as to whether the chemical is biodegradable or
water-soluble and what effect its application could have on the surrounding environment,
including waterbodies and wildlife.
Table 7-21 shows application rates for some common spray-on adhesives as recommended by
Smolen et al. (1988).
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Table 7-21. Application Rates for Spray-On Adhesives
Spray on adhesive
Anionic Asphalt Emulsion
Latex Emulsion
Resin in Water
Water dilution
7:1
12.5:1
4:1
Type of nozzle
Coarse spray
Fine spray
Fine spray
Application
(gal/acre)
1,200
235
300
Source: Smolenetal. 1988.
Effectiveness
Sprinkling/Irrigation: Not available.
Vegetative Cover: Not available.
Mulch: Mulch can reduce wind erosion by up to 80 percent.
Wind Breaks/Barriers: For each foot of vertical height, an 8- to 10-foot deposition zone develops
on the leeward side of the barrier. The barrier density and spacing will change its effectiveness at
capturing windborne sediment.
Tillage: Roughening the soil can reduce soil losses by approximately 80 percent.
Stone: The sizes of the stone can affect the amount of erosion that will take place. In areas of
high wind, small stones are not as effective as 20-cm stones.
Spray-on Chemical Soil Treatments (palliatives): Effectiveness of polymer stabilization methods
ranges from 70 to 90 percent.
Limitations
In areas where evaporation rates are high, water application to exposed soils could require near
constant attention. If water is applied in excess, runoff can result from the site and possibly
create conditions where vehicles can track mud onto public roads.
Chemical applications should be used sparingly and only on mineral soils (not high organic
content soils) because their misuse can create additional surface water pollution from runoff or
can contaminate ground water if infiltrated. Chemical applications can also present a health risk
if excessive amounts are used.
Maintenance
Because dust controls are dependent on specific site conditions including the weather, inspection
and maintenance are unique for each site. Generally, however, dust control measures involving
application of either water or chemicals require more monitoring than structural or vegetative
controls to remain effective. If structural controls are used, they should be inspected for
deterioration regularly to ensure that they are still achieving their intended purpose.
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Cost
Chemical dust control measures can vary widely in cost depending on specific needs of the site
and level of dust control desired. One manufacturer of a chloride product estimated a cost of
$1,089 per acre for application to road surfaces but cautioned that cost estimates without a
specific site evaluation can be inaccurate.
7.2.4.9. Storm Drain Inlet Protection
Description
Storm drain inlet protection measures are controls that help prevent soil and debris from on-site
erosion from entering storm drain inlets. Typically, these measures are temporary controls that
are implemented before large-scale disturbance of the surrounding site. These controls are
advantageous because their implementation allows storm drains to be used during even the early
stages of construction activities. The early use of storm drains during project development
significantly reduces the occurrence of future erosion problems (Smolen et al. 1988).
Three temporary control measures to protect storm drain drop inlets are as follows:
Excavation around the perimeter of the drop inlet
Fabric barriers around inlet entrances
Block and gravel protection
Excavation around a storm drain inlet creates a settling pool to remove sediments. Weep holes
protected by gravel are used to drain the shallow pool of water that accumulates around the inlet.
A filter fabric barrier erected around an inlet can create an effective shield to sediment while
allowing water to flow into the storm drain. This type of barrier can slow runoff velocity while
catching soil and other debris at the drain inlet. Block and gravel inlet protection uses standard
concrete blocks and gravel to form a barrier to sediments while permitting water runoff through
select blocks that are laid sideways. In addition to these materials, limited temporary stormwater
drop inlet protection can also be achieved with the use of straw bales or sandbags to create
barriers to sediment.
For permanent storm drain drop inlet protection after the surrounding area has been stabilized,
sod can be installed as a barrier to slow stormwater entry to storm drain inlets and capture
sediments from erosion. This final inlet protection measure can be used as an aesthetically
pleasing way to slow stormwater velocity near drop inlet entrances and remove sediments and
other pollutants from runoff.
A new technology that uses an insert trap into the inlet itself has been developed (Adams et al.
2000). This technique showed good results on initial tests, trapping more than 50 percent of the
incoming sediment in flows typical of those into urban storm drains. This technique is being
further developed with a pending patent application.
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Applicability
All temporary controls should have a drainage area no greater than 1 acre of drainage area per
inlet. It is also important for temporary controls to be constructed before disturbing the
surrounding landscape. Excavated drop inlet protection and block and gravel inlet protection are
applicable to areas of high flow where overflow is anticipated into the storm drain. Fabric
barriers are recommended for smaller, relatively flat drainage areas (slopes less than 5 percent
leading to the storm drain).
Temporary drop inlet control measures are often used in combination with each other and with
other stormwater control techniques.
Design and Installation Considerations
Hydrologic Design
Hydrologic computations are not necessary with present technologies. A specified limitation of 1
drainage acre per inlet limits flow rates, dependent on local rainfall and runoff considerations.
Installation Criteria and Specifications
The following criteria should be followed until future research establishes better techniques:
With the exception of sod drop inlet protection, these controls should be installed
before any soil disturbance in the drainage area.
Excavation around drop inlets should be dug a minimum of 1 foot deep (2 feet
maximum) with a minimum excavated volume of 35 cubic yards per acre disturbed.
Side slopes leading to the inlet should be no steeper than 2:1. The shape of the
excavated area should be designed such that the dimensions fit the area from which
stormwater is anticipated to drain. For example, the longest side of an excavated area
should be along the side of the inlet expected to drain the largest area.
Fabric inlet protection is essentially a filter fence placed around the inlet. The fabric
should not be used as a stand-alone sediment control measures. To increase inlet
protection effectiveness, these practices should be used in combination with other
measures, such as small impoundments or sediment traps (USEPA 1992). Temporary
storm drain inlet protection is not intended for use in drainage areas larger than 1
acre. Generally, stormwater inlet protection measures are practical for relatively low
sediment and low volume flows.
Frequent maintenance of storm drain controls is necessary to prevent clogging. If
sediment and other debris clog the water intake, drop intake control measures can
actually cause erosion in unprotected areas.
Maintenance
All temporary control measures must be checked after each storm event. To maintain the
sediment capacity of the shallow settling pools created from these techniques, accumulated
sediment should be removed from the area around the drop inlet (i.e., from the excavated area,
around the fabric barrier, or around the block structure) when the sediment storage is reduced by
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approximately 50 percent. Additional debris should be removed from the shallow pools
periodically.
Weep holes in excavated areas around inlets can become clogged and prevent water from
draining from the shallow pools that form. Should this happen, unclogging the water intake can
be difficult and costly.
Cost
The cost of implementing storm drain drop inlet protection measures will vary depending on the
control measure chosen. Generally, initial installation costs range from $50 to $150 per inlet,
with an average cost of $100 (USEPA 1993). Maintenance costs can be high (annually, up to 100
percent of the initial construction cost) because of frequent inspection and repair needs. The
SWRPC has estimated that the cost of installation of inlet protection devices ranges from $106 to
$154 per inlet (SWRPC 1991).
7.2.4.10. Polyacrylamide (PAM)
General Description
The term polyacrylamide (PAM) is a generic term that refers to a broad class of compounds.
There are hundreds of specific PAM formulations, and all have unique properties that depend on
polymer chain length and number and kinds of functional group substitutions along the chain.
PAMs are classified according to their molecular weight and ionic charge and are available in
solid, granular, liquid, or emulsion forms.
The effectiveness of PAMs to prevent or reduce erosion is due to its affinity for soil particles,
largely via coulombic and Van der Waals attraction. These surface attractions enhance particle
cohesion, stabilizing soil structure against shear-induced detachment and transport in runoff. In a
soil application, PAM aggregates soil particles, increasing pore space and infiltration capacity
and resulting in reduced runoff. These larger particle aggregates are less susceptible to raindrop
and scour erosion, thus reducing the potential to mobilize sediments.
Applicability
Because of ease in application, PAM is well suited as a short-term erosion prevention BMP,
especially for areas with limited access or steep slopes that hinder personnel from applying other
cover materials. PAM can be used to augment other cover practice BMPs, though it can be
effective when applied alone. Thus, the ease of application, low maintenance, and relatively low
cost associated with PAM make it a practical solution to soil stabilization during construction.
Application Criteria
PAM can be applied to soil through either a dry granular powder or a liquid spray form. Optimal
application rates to prevent erosion on construction sites are generally less than 1 kg/ha
(approximately 1 Ib/ac) (Tobiason et al. 2000). However, the concentration required can vary for
specific soil properties and construction phases. WDOT (2002) suggests a dosage of 60 mg/L for
roadway erosion and sediment control. This is higher than the rate recommended by the
University of Nebraska for an agricultural application (10 parts per million). To put this into
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context, one half pound of PAM in 1,000 gallons of water results in a PAM concentration of 60
mg/L, which treats 1 acre of exposed soil according to WDOT recommendations.
Effectiveness
A study performed in Dane County, Wisconsin, analyzed 15-meter-square plots for runoff and
sediment yield on a construction site. The study concluded that when a solution of PAM-mix
with mulch/seeding was applied to dry soil and compared with the control (no PAM-mix
application to dry soil), an average reduction of 93 percent in sediment yield was found. The
lowest performance (average reduction in sediment yield of 77 percent) occurred when PAM-
mix in solution was applied to moist soil. The application of dry PAM-mix to dry soil reduced
sediment by 83 percent and decreased runoff by 16 percent when compared to the control. The
results show that regardless of the application method, PAM-mix was effective in reducing
sediment yield in the test plots (Roa-Espinosa et al. 2000).
A second study performed in Washington analyzed the runoff from three different construction
sites: an erosion control test facility, a highway construction site, and an airport runway. Table 7-
22 summarizes the 225 samples analyzed by Tobiason et al. (2000).
Table 7-22. Turbidity Reduction Values from PAM
Maximum
Median
Minimum
Volume
(m3)
350
285
133
Turbidity reduction
(%)
99.97
97.6
46
Limitations
PAMs are most commonly produced as dry granules. They completely dissolve and remain
dissolved if mixed properly. If added too quickly or if not stirred vigorously, the granules rapidly
form nondissolvable gels on contact with water or collect in low turbulence areas as syrupy
concentrations that dissolve slowly in an uncontrolled pattern over a period of hours or days
(Sojka and Lentz. 1994). In addition, when spilled on hard surfaces, PAM solutions are
extremely slippery and hazardous to foot and vehicle traffic. PAM dust is highly hygroscopic
and, if inhaled, could impair breathing. Certain neutral and cationic PAMs at very high exposure
levels produce irritation in humans and are somewhat toxic to certain aquatic organisms;
therefore, PAM should be used in strict compliance with state and federal label requirements.
Cost
The cost of PAM ranges from $1.25 per pound to $5.00 per pound (Entry et al. 1999). The cost
of PAM application depends on the system employed. PAM can be used in a centralized
treatment system (e.g., at a sedimentation basin) to treat larger areas, or dispersed in granular or
liquid form. In Tobiason et al. (2000), the startup costs for the batch treatment system amounted
to $90,000. Monthly expenses averaged $18,000 for operations and maintenance and $13,000 for
materials and equipment. The total costs for this phase totaled about $245,000, less than 1
percent of total construction costs. If dispersed through irrigation systems (for agriculture), the
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seasonal cost of PAM treatment is $9 to $15 per acre (Kay-Shoemake et al. 2000), where a
season probably requires between 5 and 10 applications.
For construction sites, it is more likely that PAM would be applied as an additive to the
hydroseed mix and applied when final grade is established and cover vegetation is installed.
There are numerous suppliers who provide PAM as a low-cost additive for hydroseeding,
suggesting PAM application costs can be incorporated into that of hydroseeding ($540 to $700
per acre depending on which seed is applied). An additional cost would be incurred to sample
site soils to customize the dosage and delivery mechanisms for individual sites. In addition,
reapplication of PAM in granular or liquid form to areas with rill development (poor vegetation
cover) would require additional funds. Where reapplication of granular PAM is used, R.S. Means
(2000) suggests a cost of approximately $5 per 1,000 square feet for spreading soil admixtures
by hand.
7.2.5. ADVANCED TREATMENT AND CONTROL TECHNOLOGIES
7.2.5.1. Active Treatment Systems (ATS) Technologies
EPA researched technologies available for treating construction stormwater runoff, with the
specific goal of identifying technologies that could reliably meet an effluent turbidity limit. EPA
primarily identified active treatment systems (ATS) that use coagulation/flocculation and
filtration for treating stormwater runoff from active construction sites as the most reliable
technology. Technologies used at construction sites to control suspended sediment and turbidity
in stormwater runoff from discharging typically include erosion control, storage/containment,
gravitational settling, chemical treatment (i.e., coagulation/flocculation), and filter media. For an
ATS to be effective, many (if not all) of the above mentioned treatment technologies need to be
incorporated into an ATS before treated effluent discharge. This section provides an ATS
process description and costs and discusses applicability, demonstration status, and limitations.
Treatment chemical addition and filtration are separately discussed in detail in subsequent
sections.
ATS Process Description and Costs
EPA assumed that the key components of an ATS would include the following:
On-site storage by using a combination of sediment basins, tanks or other
impoundments
Chemical addition (see Section 7.2.5.2 )
Mix tank/clarification tank
Media filtration (see Section 7.2.5.3)
Instrumentation (e.g., monitoring of influent and effluent)
The ATS capital costs include purchased (or leased) equipment cost, including ancillary
equipment (e.g., piping, valves, and controllers), delivery cost, and installation/construction cost
(including labor and site work). The ATS annual (operation and maintenance) costs include
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treatment chemicals, operating labor and material, maintenance labor and material, energy, waste
disposal, monitoring, and rented equipment.
The ATS are typically equipped with automated instrumentation to monitor water quality, flow
rate, and dosage control for both influent and effluent flows. Following the
coagulation/flocculation process, the densified floe is settled out via gravitational settling,
skimming, or media filtration (e.g., sand, gravel, bag filters).
EPA determined that some vendors offer gel socks containing treatment chemical, often for
pretreatment of stormwater runoff. For example, the StormKlear Gel-Floe is a fabric sock
containing a flake form of chitosan that slowly dissolves as the influent stormwater flows over it.
The gel sock is typically anchored within the influent pipe of the ATS.
An ATS can be in either a batch or flow-through design, as described in Table 7-23. The ATS
design depends upon factors including: existing structures (e.g., detention basins, storm sewer
systems, sump areas), influent turbidity, flow rate, and space limitations. Clear Creek Systems,
Inc., in a comment letter to the California State Water Resources Control Board (Gannon 2007)
regarding the draft construction general permit, stated that "Batch treatment is a relatively
outdated and inefficient method of operations."
Table 7-23. ATS Operating Modes
Operation mode
Batch (Pump-Treat-Hold-Test
Release)
Flow-through or continuous
treatment
Description
Stormwater runoff is collected, stored or contained in a basin or tank
until treatment is complete before discharging.
Involves pumping stormwater runoff from a collection, storage or
containment basin, treating the water, and directly discharging.
Source: ATS Industry Task Force 2007.
Figure 7-1 presents a general ATS batch operating mode process diagram. The batch treatment
process incorporates a period of time for treatment in a settling, mixing, and/or holding tank(s)
before discharge. This is different from the continuous flow or flow-through treatment process in
which treatment and discharge occurs continuously. Figure 7-2 shows an ATS using continuous
mode.
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Shut-off valve
Instrumentation (e.g.,
\ pH, turbidity, flow
meter, etc.)
STORM WATER RUNOFF
COLLECTION/SETTLING
[Sediment Basin (if
available), Sump Area,
Piping, etc ]
Settling, Mixing and
Holding Tank (multiple
tanks in series or parallel if
applicable)
Chemical
coagulant/flocculant
metering pump
Figure 7-1. General ATS Batch Operating Mode
Effli
/ /
'uent Line /
-^T \
RECEIVING WATERS
; i
Shown without Instrumentation (e.g., /
optional media pH, turbidity, etc.)
filtration
SITE STORM WATER RUNOFF
Effluent Diversion
STORM WATER RUNOFF \
DETENTION STRUCTURE
Backwash Return
instrumentation (e.g
pH, turbidity, flow
meter, etc.)
STORM WATER
DETENTION STRUCTURE
Chemical
coagulant/flocculant
metering pump
Media Filtration
(e.g., bag,
cartridge, sand
filters)
Shut-off valve
Effluent Line /
T
RECEIVING WATERS
Instrumentation (e.g.,
pH, turbidity, flow
meter, etc.)
Figure 7-2. Flow-through ATS Operating Mode
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ATS Applicability
The ATS is well suited as a method of runoff control when traditional BMPs are not capable of
meeting numeric standards. ATS provides quick and efficient removal of fine-grained,
suspended sediment or colloidal particles and can be custom tailored for site-specific
requirements. Gravitational settling of fine or colloidal soil particles can have limited
effectiveness and might not be completed in a timely manner. Therefore, ATS could be
necessary to enhance small particulate solids removal and minimize project timelines and costs.
The ATS can minimize potential adverse environmental impacts to receiving water through
automated water quality measurements. ATS generally produces very low turbidity values (often
< 10 nephelometric turbidity units [NTU]) in the effluent discharge.
The vendors contacted by EPA stated that ATS were typically meeting discharge standards of 10
NTU or less. Therefore, ATS would work well for a low NTU standard. Vendors reported little
cost savings in designing an ATS for higher, less stringent, NTU limits (e.g., 50, 100, 150, 200,
250 NTU).
Demonstration Status
EPA determined from information obtained from vendor calls that ATS using chemical treatment
with polymer coagulation/flocculation was prevalent in the industry. The majority of the vendors
contacted are using the polymer chitosan in conjunction with gravitational settling and filtration
for the treatment of stormwater runoff. EPA did not obtain information on how many of these
systems are batch or flow-through treatment systems. The polymer Diallydimethyl-ammonium
chloride (DADMAC) was also used frequently by vendors. Following the chemical treatment,
media filtration is commonly used. Sand filters in combination with small micron (e.g., 0.5)
parti culate filters appeared to be the media of choice by many of the vendors for removing the
floe material and polishing. However, bag and cartridge filters are also being used either as a
stand-alone treatment or in combination with the sand filters for treatment purposes. Many of the
treatment technologies used are very site-specific according to the water quality (i.e., turbidity,
chemical composition) and footprint available.
The vendors contacted have implemented ATS primarily in the northwest (California, Oregon,
and Washington). Washington State's Department of Ecology (WDEC) has a new technology
evaluation program in which vendors complete a Chemical Technology Assessment Protocol -
Ecology (CTAPE) for new and emerging technologies. Following a performance evaluation,
vendors may receive a conditional use designation (CUD) or a general use level designation
(GULD) for a particular chemical treatment technology. For construction sites, WDEC has
approved conditional use or general use designations for Chitosan-enhanced sand filtration using
StormKlear Liquifloc, FlocClear, and Chitovan chemical treatments. Table 7-24 shows
known or draft state ATS requirements or recommendations at the time of this writing.
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Table 7-24. ATS State Requirements/Recommendations
State
ATS requirements and/or recommendations
California
(draft permit)
This draft NPDES construction general permit provides specific requirements for
dischargers who choose to use an ATS.
ATS shall be designed to capture and treat a volume equivalent to the runoff from a 10-
year, 24-hour storm event in a 72-hour period with a runoff coefficient of 1.0. ATS shall
include residual tests certified by a California State laboratory. Effluent toxicity testing
and instrumentation must be utilized.
Numeric standards:
All discharges - pH lower 6.0 to upper 9.0
All other than ATS - 1000 NTU
For ATS discharges - 10 NTU (daily flow-weighted average) and 20 NTU any single
sample (notes that soil particles smaller than 20 microns (i.e., finer than medium silt) do
not settle easily using conventional methods).
Basin sizing
At a minimum, be designed for an 80% reduction of suspended soil particles having a
diameter of 20 microns or larger. Minimum of 3,600 ft3/acre or 2-year 24-hour storm
(perforated riser sized to discharge the runoff volume over a 24 to 72-hour period).
Referenced California Storm Water BMP Handbook Construction, Sediment Basin SE-2,
January 2004.
Oregon
Mr. Dennis lurries with the Oregon Department of Environmental Quality (DEQ) stated
that ATS is not required; however, for sites with difficulty reaching water quality
standards, it is recommended that a chitosan-enhanced sand filtration treatment be
implemented.
Water Quality Requirements
If discharging to a 303(d) listed waterbody or a waterbody with a TMDL for sediment
and turbidity, sampling for turbidity is required to meet a 160 NTU benchmark. If unable
to meet benchmark then an Action Plan utilizing a BMP such as water treatment utilizing
electro-coagulation, chemical flocculation or filtration shall be implemented.
Washington
BMP C250 Construction Storm Water Chemical Treatment states that formal written
approval from the Department of Ecology is required for the use of chemical treatment
regardless of site size. Through the use of the Washington CTAPE, new technology
evaluation program, the following have been accepted with use designations:
Construction Site Treatment Technologies
Chitosan-Enhanced Sand Filtration Using StormKlear LiquiFloc (GULD)
Chitosan-Enhanced Sand Filtration Using FlocClear(GULD and CUD)
Chitosan Enhanced Sand Filtration Using ChitoVan (CULD and GULD)
Water Tectonics Electrocoagulation Subtractive Technology (CUD)
GULD - General Use Level Designation
CUD - Conditional Use Designation
Water Quality Requirements
Sites that disturb more than 1 acre are required to sample for turbidity. Turbidity
benchmark of 25 NTU or for 25 to 250 NTU implement BMPs and revise SWPPP. >250
NTU no more than 5 NTU over background if less than 50 NTU, or no more than 10%
over background if background is 50 NTU or greater.
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ATS Limitations
Treatment chemicals must have the proper dose and contact time to avoid potential toxicity in
effluent discharges. Many of the polymers used in ATS precipitate only in a designated pH range
(e.g., 6.5 to 8.5).
ATS Costs
EPA obtained ATS costs (i.e., chitosan-enhanced sand filtration) from three vendors. The ATS
costs associated with the treatment of active construction site stormwater runoff, as provided by
vendors, is included in Table 7-25. For estimating compliance costs for the regulation, EPA used
a value of $0.02 per gallon treated. EPA also added costs for providing storage for impounding
runoff from the 2-year/24-hour storm event as an approximation of the additional costs for
storage that might be required on-site. The costs associated with ATS vary by site-specific
factors such as turbidity, available footprint area for basins and/or equipment, effluent discharge
requirements, etc. In addition to the data provided by vendors, EPA obtained cost data on
specific projects incorporating ATS from several reports. Table 7-26 summarizes ATS costs for a
number of case studies reflecting varying site sizes and different system configurations.
Table 7-25. Summary of Preliminary Vendor Costs
Cost type
Total Cost
Total Cost
Labor
Chemical
Equipment
Rental
(18 month rental)
Large Site
Small Site
Large/Small
Large Site
Small Site
All Sites
10-acre Site
50-acre Site
100-acre Site
Cost
(2008 dollars)
$0.005/gal
$0.01/gal
$0.01-0.03/gal
$l,250/Mgal
$5,000/Mgal
$l,000-$8,000/Mgal
$130,000
$250,000
$500,000
Source
StormKlear
Clear Water
Clear Creek
For additional details on ATS and on ATS costing, see DCNs 43000 through 43011 and
Section 9.
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Table 7-26. Summary of Advanced Treatment System Case Studies
Project
City of Redmond
City of Redmond
(2 sites)
Confidential
Builder Project #1
Confidential
Builder Project #2
Type of ATS*
CESF
Electrocoagulation
CESF
DADMAC
Approximate
treated volume
1 million
gallons
6.2 million
gallons
~ 100 million
gallons
~ 15 million
gallons
Project
duration
(months)
2.5
Unknown
Unknown
Project size
(acres)
32
8 and 23
acres
>500
~ 300 acres
Cost per
gallon
$10.22 per
thousand
gallons
$5.83 and
$8.00 per
thousand
gallons
$16.00 per
thousand
gallons
$36.00 per
thousand
gallons
*CESF = Chitosan-Enhanced Sand Filtration, DADMAC = Diallyldimethyl Ammonium Chloride
7.2.5.2. ATS Coagulation/Flocculation
The effective design of an ATS relies heavily on an analysis of site conditions (e.g., land use,
soils, toxins, water chemistry, flowrate, receiving water chemistry). Coagulants and flocculants
function as the primary treatment process used in ATS. Treatment chemical addition to influent
stormwater runoff is to destabilize the suspended particles by various mechanisms, aggregating
into larger particles that are easier to remove through settling or filtering. Coagulation is the
reduction of the net electrical repulsive forces at particle surfaces by adding coagulating
chemicals, whereas flocculation is the agglomeration of the destabilized particles by chemical
joining and bridging.
The coagulants/flocculants are typically added to the influent via an injection pump in a metered
dose just upstream of the clarifier tank or basin. The treatment chemicals are allowed to mix to
maximize the formation of a dense floe. Proper dosing of the treatment chemicals is critical to
minimize toxicity, maximize system efficiency, and ensure proper effluent water quality. The
optimum dose is very site-specific (e.g., varying with changing types of soils, flow rate) and
should be based on a series of jar tests.
Water treatment chemicals are predominately water soluble and classified as cationic (positively
charged), anionic (negatively charged), nonionic (neutral), or amphoteric (changeable depending
on the pH of water). Table 7-27 lists common coagulants, regulatory status, and available
residual tests. Several of these common coagulants and toxicity information is discussed below.
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Section 7: Technology Assessment
Table 7-27. Examples of Some Commonly Available Coagulants
Coagulant
Description
Regulatory status
Approved dosage (or
dosage where no
toxic effects are
observed)
Residual test
available1
Method detection
limit of residual
Chitosan
Chitosan
acetate
based
cationic
biopolymer
Approved
in
Washington
N/A
Presence/
absence
O.lmg/L
presence/
absence
PAC
Poly-
aluminu
m
chloride
N/A
N/A
DADMAC
Diallyl-
dimethyl-
ammonium
chloride
N/A
N/A
PAM
Poly-
acrylamide
Approved in
Florida, New
Hampshire
Florida has no
limit
New
Hampshire has
limit of !/2 of
NOEC2 or
IC253
PASS
Poly-
aluminum
chloride
Silica/sulfate
modified
N/A
N/A
Alum
Aluminum
sulfate
Approved in
Florida
No limit
Presence/absence and quantitative
<0.5 mg/L presence/absence
0.5 mg/L quantitative
1 Residual tests can be presence/absence tests or quantitative tests. A presence/absence test verifies that a chemical is
or is not present at or above a method detection limit; it does not quantify (with a numerical value) how much is
present above the method detection limit. A quantitative test yields the concentration of the chemical at or above the
method detection limit; it t typically yields a concentration in mg/L.
Source: ATS Industry Task Force 2007.
2 NOEC: No Observed Effect Concentration. Highest concentration of effluent where the effect (e.g., reproduction) is
not significantly different from the control.
3IC25: 25 Percent Inhibition Concentration. Concentration causing a 25 percent reduction in the effect.
N/A - Not Available
Chitosan acetate
This polymer is widely used at active construction sites in ATS for stormwater runoff.
Specifically, Washington, Oregon, and California have had numerous projects using this
polymer. It is an approved, general-use-level designated polymer for treating construction site
runoff in Washington State. Chitosan is derived from chitin, the major component of crustacean
shells and is a cationic polyelecrolyte. It is a very plentiful natural polymer with supply
stemming from shellfish wastes. Chitosan is able to coagulate/flocculate non-polar hydrocarbons
(e.g., oil), suspended sediment, and to chelate heavy metals (Nichols 1997).
Table 7-28 presents information from several studies regarding toxicity of chitosan acetate to
aquatic organisms, chemical hazard information, and filter pass-through results.
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Section 7: Technology Assessment
Table 7-28. Chitosan Acetate Study Results
Vendor/source
MacPherson 2006a (references
Nautilus Environmental,
Redmond, Washington 2004)
Bullock et al. 2000
ProTech GCS 2004
MacPherson 2006b
Blandford 2006
Ray 2001
Mirsky (Boise State
University) 2007
Results
Toxicitv. Chitosan acetate (1% solution) was reported to have an LC50 for
Daphnia pulex of 1,370 mg/L, 642 mg/L for fathead minnow, and 168 mg/L
for rainbow trout in clean water and 452 mg/L in 500 NTU water.
Toxicitv. The toxicitv of chitosan has generally been considered to be non-
toxic; however, Chitosan when dissolved in acetic acid and added to a
culture system at 1.0 parts per million (ppm) to remove organic solids was
found to have acute toxicity to rainbow trout, related to gill lesions and the
severity was dose dependent.
Toxicitv. ProTech GCS in conjunction with GE Betz conducted research on
the polymer chitosan (1% solution). The test was conducted using > 1000
NTU water from a Sacramento, CA project site. Survival rates for daphnia
magna, rainbow trout, and fathead minnow were 100 percent at a dose of
1,100 ppm and 2,200 ppm.
Toxicitv/Filter pass-through. Chitosan is trapped in the sand filter and not
released into the receiving water.
Filter pass-through. A study evaluating the retention of chitosan acetate in a
mixed media filter (anthracite, sand, and garnet) was conducted by GE Betz.
The results upon a side-by-side comparison for Klaraid PC 1 192
(DADMAC) with chitosan acetate demonstrated that both products pass
through a standard mixed media filter without any retention within the layers
of the filter.
Hazard. This polymer is listed as Resource Conservation and Recovery Act
(RCRA) hazardous due to the acidity (at a pH of about 4).
Hazard. Chitosan acetate (1% solution) has a pH of 3.9 to 4.0 and is reported
to be mildly irritating to the eyes.
Residual Tests. The Natural Site Solutions (NSS) 2004 Residual Chitosan
Test (RCT) field test procedure showed that blank samples could not be
distinguished visually from samples containing chitosan acetate. These test
results indicate that the NSS 2004 RCT cannot be employed by field
technicians to determine the presence or absence of chitosan in treatment
system effluent.
Diallydimethyl-ammonium chloride (DADMAC)
This polymer is also used in ATS for treating construction site stormwater runoff. DADMAC is
considered to be water soluble over a wide pH range. It has a high affinity for suspended
sediment but can have the ability to pass through treatment media to the receiving water
(MacPherson 2006a).
Table 7-29 presents information from several studies regarding toxicity of DADMAC to aquatic
organics, and filter pass-through results.
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Section 7: Technology Assessment
Table 7-29. DADMAC Acetate Study Results
Vendor/source
Macpherson 2006a
Macpherson 2006a
ProTech GCS, Inc., in
conjunction with GE Betz
Results
Toxicity. Tramfloc, Inc. reports daphnia magna, 48-hour LC50 of 0.23
mg/L for the Tramfloc Polydadmac 552, 553 and 557 products; however,
aquatic toxicity is reduced by factors of 10 to 100 times in the presence
of 5 to 10 mg/L organics found in most surface waters.
Filter pass-through. High affinity for suspended sediment but might have
the ability to pass through treatment media to the receiving water
Toxicity. Demonstrated that, on a dose/response basis, DADMAC
reduced >1000 NTU water to 2 NTU at a dose of 25 ppm. In addition,
aquatic toxicity testing revealed a 95%, 100%, and 100% survival rate
for daphnia magna, rainbow trout, and fathead minnow, respectively.
The ProTech and GE study reported that the polymer DADMAC was the
most economical for its removal of suspended sediment and disposal
costs.
Polyacrylamide (PAM)
PAM are a broad class of compounds that include cationic (positively charged) and anionic
(negatively charged) polyacylamides. PAM are water soluble over a wide pH range and exhibit a
high affinity for suspended sediment.
Table 7-30 presents information from several studies regarding toxicity of PAM to aquatic
organics and hazard information.
Table 7-30. PAM Study Results
Vendor/source
(see Section 7.2.4.10)
MacPherson 2006a
Results
Toxicity. At very high doses irritation in humans and a toxicity to certain
aquatic organisms can be observed; however, in general PAMs are
considered to be non-toxic to aquatic organisms.
Hazard. PAM in the solid state has highly hygroscopic dust and, if
inhaled, could impair breathing.
Toxicity. Anionic PAM's are not expected to be toxic to aquatic life at
normal dose rates (LC50 for most aquatic species is greater than 100
mg/L).
PAMs have been approved for use in Florida and New Hampshire (ATS Industry Task Force
2007). In California, Washington, Michigan, and Oregon, cationic PAM cannot be used for
construction site soil stabilization practices (MacPherson 2006a).
Aluminum-Based Coagulants
The aluminum-based coagulants do not appear to be as widely used in ATS at construction sites
for stormwater runoff. Table 7-31 presents aluminum toxicity on aquatic organisms. Note that
Page 7-95
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Section 7: Technology Assessment
aluminum floe will be in various aluminum complexes, which can become aqueous aluminum
dependent on time and site-specific physical and environmental conditions (e.g., pH,
temperature, hardness and alkalinity, release of trapped sediment).
Table 7-31. Aluminum-based Coagulant Study Results
Vendor/source
MacPherson 2006a
Sutherland 1999 (references
Oughton 1992)
ProTech GCS, Inc., in
conjunction with GE Betz
MacPherson 2006a
Results
Toxicitv. Specifically, studies with juvenile striped bass indicate that
this species is extremely sensitive to several forms of aqueous
aluminum (referenced Driscoll et al. 1980; Palawski et al. 1985;
Skogheim and Rosseland 1986; Rosselan et al. 1992).
Toxicitv. An in situ study (Hall et al. 1985) with larval striped bass
found 90 to 99% mortality in river water with 0.48 to 4. 1 mg/L
aluminum and pH levels between 6.0 and 6.8
Toxicitv. Klauda et al., (1989) supported the theory that monomeric
aluminum (mAl), the inorganic fraction, was potentially the most toxic
to early life stages of migratory fish.
Toxicitv. Polymers created from aluminum and water collect on gills
and limit respiration.
Toxicitv. ProTech GCS and GE Betz conducted a study using the
coagulant/flocculant Aluminum Chlorhydroxide and found that at
optimum dose (75 ppm) survival rates for Daphnia Magna, rainbow
trout, and Fathead minnow were 95%, 100%, and 95%, respectively.
At two times the optimum dose (150 ppm) results were similar,
showing no increased toxicity.
Hazard. These aluminum-based water treatment agents also pose a risk
to human eyes and skin if not properly handled.
7.2.5.3. ATS Filtration
Filtration is a final treatment step in ATS designed to remove residual, low concentrations of
target pollutants before discharge. Multimedia filtration (mixed-media filtration) is one of the
oldest and most widely applied types of filtration for the removal of suspended solids from
aqueous liquid streams. This form of filtration uses a bed of granular particles as the filter
medium. Granular media filters are used to remove suspended solids from construction
stormwater after chemical addition creates a floe to filter. The bed can consist of one type of
medium (e.g., sand) of the same particle size, or multiple particle sizes. Different types of media
(e.g., sand and gravel, sand and anthracite) with differing densities and different particle sizes
compose the bed of a multimedia filter. Multimedia filters can be more efficient but more
expensive and complex than single-media filters. For this reason, sand filters are most commonly
used in construction ATS. The filter bed is contained within a basin or tank and is supported by
an underdrain system, which allows the filtered liquid to be drawn off while retaining the filter
medium in place. As suspended particle-laden water passes through the bed of the filter medium,
particles are trapped on top of and within the bed. Once the pressure drop across the filter is large
enough to impede flow, the filter is backwashed and the backwash water is typically re-
circulated to the influent flow.
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Section 7: Technology Assessment
Vendors are also marketing bag and cartridge filters that can be used as a final filtration step.
Bag filters are available in a range of pore sizes, and cartridge filters are available with various
media types. These filters can be used as a final polishing step before discharge.
7.2.5.4. Other Emerging Treatment Technologies
While EPA's analysis was based primarily on chitosan-enhanced filtration, there are several
other advanced technologies available to treat construction site stormwater runoff. Work in
recent years has focused on a number of passive, PAM-based systems to enhance pollutant
removal in sediment basins. PAM, available mfloc logs, has also seen increased placement in
conveyance channels. As water flows through the channel, PAM dissolves and the turbulence in
the channel aids in the flocculation process. Floes can then settle out in sediment control devices,
such as check dams, sediment traps or basins. In addition, electrocoagulation has been
successfully used on a number of construction sites to meet turbidity limits. At least one vendor
is also using a tube settler coupled with polymer addition before filtration to aid in sediment
removal. Other recent advancements include using a skimmer to enhance sediment removal in
sediment basins, and using porous baffles in sediment basins to reduce turbulence and increase
removal efficiencies. North Carolina now requires skimmers on all sediment basins, and the
North Carolina Department of Transportation has developed draft standards for the use of porous
baffles in sediment basins (See DCNs 43083 and 43045, NCDOT draft baffles standards and
North Carolina Erosion and Sediment Control Planning and Design Manual with requirements
for skimmers). McLaughlin demonstrated the ability to meet a 50-NTU limit at a research site in
North Carolina by adding PAM to a basin equipped with baffles and a surface skimmer (see
DCN 43082, The Potential for Substantial Improvements in Sediment and Turbidity Control).
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Stahre, P., and B. Urbonas. 1990. Stormwater Detention for Drainage, Water Quality, andCSO
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of Water shed Protection. Center for Watershed Protection, Ellicott City, MD. 2000.
.
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Section 8: Regulatory Development and Rationale
8. REGULATORY DEVELOPMENT AND RATIONALE
In this section, the methodology used by U.S. Environmental Protection Agency (EPA) to
develop regulatory options for the construction and development (C&D) industry is described.
This section discusses the regulatory options evaluated for the proposed rule. The costs of
regulatory options are discussed in Section 9 of this document. A description of the estimated
pollutant reductions expected for each regulatory option is presented in Section 10. The C&D
industry financial analyses can be found in the EPA's Economic Analysis of Proposed Effluent
Guidelines and Standards for the Construction and Development Category (EPA-821-R-08-
008). This section also includes discussion of EPA's Best Conventional Pollutant Control
Technology (BCT) cost-reasonableness analysis.
8.1. DEVELOPMENT OF REGULATORY OPTIONS
EPA considered a series of regulatory options. These options were designed to control the
discharge of sediment, stormwater and other pollutants from sites when construction is taking
place. EPA considered a range of options that incorporate varying levels of control strategies.
The following discussion presents various options that EPA considered.
8.2. OPTIONS CONTAINED IN THE PROPOSAL
8.2.1. OPTION 1 - COMBINATION OF BEST MANAGEMENT PRACTICE (BMP)
STANDARDS AND SEDIMENT BASIN SIZING
Option 1 would establish minimum sizing criteria for sediment basins used at construction sites
with 10 or more disturbed acres draining to one location. Under this option, permittees would be
required to install sediment basins that provide either 3,600 cubic feet per acre of runoff storage,
or be designed to store runoff from the local 2-year, 24-hour storm event. This option also
includes requirements for implementing a variety or erosion and sediment controls on all
construction sites that are required to obtain a permit.
8.2.2. OPTION 2 - COMBINATION OF BMP STANDARDS FOR ALL SITES AND
TURBIDITY STANDARD FOR SELECTED SITES
Option 2 contains the same requirements as Option 1. In addition, construction sites of 30 or
more acres would be required to meet a numeric turbidity limit in stormwater discharges from
the site. This requirement would apply if the construction site is in an area where the rainfall
runoff erosivity factor (R factor) as defined in the Revised Universal Soil Loss Equation
(RUSLE) is greater than or equal to 50 and if the soils present on the construction site contain 10
percent or more by mass of soil particles smaller than 2 microns in diameter.
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Section 8: Regulatory Development and Rationale
8.2.3. OPTION 3 - COMBINATION OF BMP STANDARDS FOR ALL SITES AND
TURBIDITY STANDARD FOR ALL SITES 10+ ACRES
Option 3 contains the same requirements as Option 1. Option 3 also requires all sites with 10 or
more acres of disturbed land to meet a numeric turbidity standard, regardless of the R-factor or
soil types.
8.3. OTHER OPTIONS EVALUATED
In addition to the three options discussed in the proposal, EPA considered a number of other
options. The various option parameters that EPA considered are as follows.
8.3.1. SITE SIZE
EPA's proposed option requires turbidity limits only on sites 30 acres or larger. EPA also
considered other site size cutoffs, such as 10 acres, 20 acres, and 40 acres.
8.3.2. ANNUAL PRECIPITATION
EPA considered annual precipitation as a potential applicability provision for the turbidity
standard. EPA evaluated annual precipitation cutoffs of 10, 20, 30, and 40 inches per year. EPA
considered annual precipitation as an applicability provision based on the assumption that
construction sites in arid areas should not need to install active treatment systems to meet a
turbidity limit when the likelihood of appreciable precipitation is very small. Because of the
expense of equipment rental, it might be costly for construction sites in arid areas to have the
equipment on-site to be prepared for storm events, and the likely pollutant removals in these
areas would be very small. EPA chose not to base the applicability provision on annual
precipitation, but instead based it on the RUSLE R-factor. The R-factor takes into consideration
both rainfall energy and intensity.
8.3.3. SOIL PARAMETERS
EPA considered soil properties as a potential applicability provision. Soil is a complex mixture
of a variety of minerals and organic materials composed of a range particle sizes, ranging from
large boulders and cobbles, to sand-sized particles to very small clay and silt-sized particles.
There are a number of soil classification systems in existence, but according to ASTM, sand-
sized particles range from 75 microns to 4.75 millimeters, while silts range from 5 microns to 75
microns, and clays range from 1 micron to 5 microns in diameter. Particles smaller than 1 micron
in diameter are referred to as colloids. The U.S. Department of Agriculture (USD A) uses a
different classification system. USD A, in data published in soil surveys, characterizes clay
particles as being smaller than 2 microns, silt particles as being between 2 microns and 50
microns, and sand as being between 50 microns and 2 millimeters. Generally, large particles
such as sands and coarse and medium silts in stormwater runoff from construction sites are easily
removed by conventional BMPs such as silt fence and sediment basins and traps. This is because
these particles settle very easily in a short amount of time, on the order of a few seconds to a few
hours. However, very small particles, such as fine silts and clays, generally will not settle in a
sediment basin. Detention times on the order of weeks or even years might be required for many
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Section 8: Regulatory Development and Rationale
of these particles to settle. To remove these small particles, some sort of chemical addition or
filtration is usually needed. Because soils containing predominately larger-diameter particles
would be expected to be treated to a high degree in conventional BMPs such as sediment basins,
EPA evaluated clay content (using USDA's classification, which defines clay as the percentage
by mass of particles smaller than 2 microns) as a factor in determining applicability of a numeric
turbidity limit. The logic of this approach is to make the turbidity limit apply only on sites that
have the highest likelihood of discharging significant quantities of fine-grained particles. EPA
evaluated a range of clay contents as potential applicability provisions. Sites with less than the
specified amount of clay particles would not be required to meet the turbidity standard. Table 8-1
illustrates the percentage of national developed acres that would be required to meet the turbidity
standard given various percent clay content cutoffs. State level estimates are in Table 4-6 and 4-
7. These results are based on evaluation of geographic information system soil data for the
conterminous United States from the Earth System Science Center (2006) at Pennsylvania State
University (http://www.soilinfo.psu.edu/index.cgi7index.html) (see Figure 3-13) combined with
RF1-level estimates of the annual amount of construction occurring (see Appendix E). To
develop these estimates, EPA evaluated only the surface soil layer of this data set.
Table 8-1. Percent of Developed Acres Required to Meet Turbidity
Limits for Various Clay Contents
Soil percent clay content
>5%
> 10%
> 15%
> 20%
> 25%
> 30%
Percent of developed
acres covered
91%
77%
43%
19%
11%
7%
8.4. BCT COST-REASONABLENESS ASSESSMENT
This section presents a summary of the BCT methodology and the results of the two-part cost-
reasonableness test. In considering whether to propose BCT limits more stringent than the
requirements being proposed for Best Practicable Control Technology (BPT), EPA considered
whether technologies are available that would achieve greater removals of conventional
pollutants than the proposed BPT effluent limitations guidelines. EPA also considered whether
those technologies are cost-reasonable according to the BCT cost test, which compares the
incremental removals and costs associated with BCT limitations to benchmarks associated with
BPT and publicly owned treatment works (POTWs).
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Section 8: Regulatory Development and Rationale
8.4.1. BACKGROUND ON THE BCT COST TEST
In 1977 Congress amended the Clean Water Act to include section 304(b)(4)(B). This provision
specifies that, among other factors, the assessment of BCT effluent limitations must include
consideration of
. . .the reasonableness of the relationship between the costs of attaining a
reduction in effluents and the effluent reduction benefits derived, and the
comparison of the cost and level of reduction of such pollutants from the
discharge of publicly owned treatment works to the cost and level of reduction of
such pollutants from a class or category of industrial sources. . .
Accordingly, EPA developed the BCT methodology to determine whether it is cost-reasonable
for an industry category or subcategory to control conventional pollutants at a level more
stringent than would be achieved by BPT effluent limitations.
The BCT methodology was originally published on August 29, 1979, along with the
promulgation of BCT effluent limitations guidelines for a number of industry sectors (44 Federal
Register [FR] 50732). The crux of the methodology was a comparison of the costs of removing
conventional pollutants for an average-sized POTW. The Fourth Circuit of the U.S. Court of
Appeals remanded the BCT regulation and directed EPA to develop an industry cost test in
addition to the POTW test. EPA subsequently proposed a revised BCT methodology in 1982 that
addressed the industry cost test (47 FR 49176; October 29, 1982). In 1984 EPA again addressed
the BCT methodology and proposed to base the POTW benchmark on model plant costs (49 FR
37046; September 20, 1984). The final BCT methodology was published in 1986, maintaining
the basic approach of the 1982 proposed BCT methodology and adopting the use of the new
model POTW data (51 FR 24974; July 9, 1986). These guidelines state that the BCT cost
analysis "...answers the question of whether it is 'cost reasonable' for industry to control
conventional pollutants at a level more stringent than BPT effluent limitations already require."
See 51 FR at 24974. Conventional pollutants are biochemical oxygen demand (BOD), total
suspended solids (TSS), oil and grease, fecal coliform, and pH.
The final BCT methodology incorporates two cost tests to establish cost reasonableness: the
POTW test and the industry cost-effectiveness test. Each of these tests is compared with
established benchmarks, the derivation of which is described in detail in the 1986 FR notice. The
BCT cost methodology is described in more detail in the following section.
8.4.2. CALCULATION OF THE BCT COST TEST
POTW Test
The first part of the BCT cost test is the POTW test. The POTW test compares the cost per
pound of conventional pollutants removed by industrial dischargers in upgrading from BPT to
BCT candidate technologies, to the cost per pound of removing conventional pollutants in
upgrading POTWs from secondary treatment to advanced secondary treatment.
To pass the POTW test, the cost per pound of conventional pollutant discharges removed in
upgrading from BPT to the candidate BCT must be less than the POTW benchmark. The POTW
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Section 8: Regulatory Development and Rationale
benchmark presented in the 1986 Federal Register notice is $0.25 per pound (in 1976 dollars) for
industries in which the cost per pound of pollutant reduction is based on long-term performance
data. EPA used cost index data from RS Means Historical Cost Indices to update this POTW
benchmark to 2008$ according to the following equation:
Index for 2008
x Cost in 1976$=Costin 2008$
Index for 1976
173.0
46.9
: $0.25 = $0.92
Using estimated reductions for TSS, EPA then calculated the incremental costs per pound of
conventional pollutant removed ($/lb) for each candidate BCT technology option. If any
candidate technology option passes the first part of the BCT cost test (i.e., is less than the
inflation-adjusted value of $0.92 in 2008 dollars), the technology is further evaluated in the
second part of the test (R.S. Means 2008). EPA used only TSS pollutant reductions for the cost
test calculations, because of the limited data available. However, EPA expects that discharges of
oil and grease and fecal coliform would be minimal from construction sites. EPA also expects
that BOD, where present, would be removed along with TSS. Because all options pass both parts
of the BCT cost test, it is not necessary to develop estimates for reductions for the other
conventional pollutants. The results of the POTW test are presented in Table 8-2.
Table 8-2. POTW Cost Test Results
BCT
option
1
2
3
Total annual costs and
conventional pollutant
removals
Cost
(million $)
(2008$)
132
1,891
3,798
Pollutant
removals
(million Ibs)
670
26,426
50,412
Incremental costs and conventional
pollutant removals, relative to the
proposed BPTa
Cost
(million $)
(2008$)
0
1,759
3,666
Pollutant
removals
(million Ibs)
0
25,756
49,742
Cost per
pound
($/lb)
0
0.068
0.074
POTW
cost test
result
(< $0.92/lb)
Pass
Pass
Pass
a Option 1 is equal to the proposed BPT effluent limitations. Therefore, all incremental values are calculated relative
to Option 1.
Industry Cost-Effectiveness Test
The second part of the BCT cost test is the industry cost-effectiveness test, which computes the
ratio of two incremental costs. The first of these incremental costs is the cost per pound of
conventional pollutants removed in upgrading from BPT to the BCT candidate technology. This
value serves as the numerator of the ratio. The second incremental cost, which serves as the
denominator of the ratio, is the cost per pound of conventional pollutants removed by BPT
relative to no treatment (i.e., this value compares raw wasteload to pollutant load after
application of BPT). This ratio is compared to an industry cost benchmark, which is based on
POTW cost and pollutant removal data. The industry cost benchmark is also a ratio of two
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Section 8: Regulatory Development and Rationale
incremental costs: the cost per pound to upgrade a POTW from secondary treatment to advanced
secondary treatment, divided by the cost per pound to initially achieve secondary treatment. If
the industry cost-effectiveness test is lower than the industry cost benchmark of 1.29 (i.e., the
normalized cost increase must be less than 29 percent), the candidate BCT technology passes this
part of the cost test. The calculation and results of the industry cost-effectiveness test are
presented in Tables 8-3 and 8-4. Because both Options 2 and 3 fail the second part of the BCT
cost test, BCT is set equal to BPT, which is Option 1.
Table 8-3. Cost and Pollutant Removals for the Proposed BPT
Baseline
Option 1 Incremental
Total BPT
Total annual costs
(million $)
(2008$)
1,019
132
1,152
Conventional pollutant
removals
(million Ibs)
74,460
670
75,131
BPT cost per pound
($/lb)
0.015
Table 8-4. Industry Cost-Effectiveness Test Results
BCT option
1
2
3
Incremental cost per pound to
upgrade from BPT to BCT
($/lb)
0
0.068
0.074
Calculated
ratio
0
4.46
4.81
Industry cost-effectiveness
test result
(< 1.29)
Pass
Fail
Fail
8.5. REFERENCES
R.S. Means. 2008. Building Construction Cost Data. 66th ed. R.S. Means, Co., Kingston, MA.
Earth System Science Center. 2006. Pennsylvania State University, College of Earth and Mineral
Sciences, Earth System Science Center, State College, PA.
. Accessed April 2008.
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Section 9: Estimating Incremental Costs for the Proposed Regulation
9. ESTIMATING INCREMENTAL COSTS FOR THE PROPOSED
REGULATION
9.1. OVERVIEW
This section presents the approach that the U.S. Environmental Protection Agency (EPA) used
for estimating the incremental costs associated with the regulatory options considered for the
Construction and Development (C&D) industry. This section also includes discussion on the
selection and development of cost model inputs; components of cost; and the methodology for
estimating costs, including an overview of the C&D Cost Spreadsheet Model. The economic
analyses conducted for the industry are described in the document Economic Analysis for Final
Action for Effluent Guidelines and Standards for the Construction and Development Category
(EPA-821-R-08-008).
EPA's first step in estimating national costs for each proposed option was developing an array of
model construction sites (i.e., small, medium and large transportation; small, medium and large
residential; small, medium and large nonresidential) that reasonably represent common
construction site features, and factors related to state regulations, topography, and hydrology.
EPA developed per-site costs for each model construction site using national average unit costs
for control technologies. For discussion on the development of model construction sites, see
Section 9.3.1.
To scale the model construction site costs to the state and national level, EPA estimated the
number of projects in each state for each land-use category by determining the area in each state
for each land-use category and dividing by the land-use category model site area. EPA
determined the area for each land-use category from Notice of Intent (NOT) data and developed
state-specific estimates by incorporating data on new construction acreage developed annually,
obtained from the National Land Cover Dataset (NLCD) (For a discussion of development rates,
see Section 9.3.2).
When developing state-specific costs for the regulatory options, EPA considered current state
requirements (for discussion of state requirements, see Section 9.2) and evaluated incremental
costs above these existing requirements. A more detailed description of baseline and incremental
costs is included in Section 9.4.
The most significant input parameter in estimating the size and cost of treatment equipment for
model construction sites is the volume of rainfall requiring treatment. EPA estimated the amount
of stormwater runoff requiring treatment using both the drainage area of the model site, state-
specific rainfall estimates, and runoff coefficients to estimate the volume of rainfall converted to
runoff and requiring subsequent treatment. For a discussion of rainfall data and runoff coefficient
development, see Section 9.3.2.
National level costs were calculated by summing the contiguous state costs, and costs for the
District of Columbia. Costs for Alaska and Hawaii, as well as the U.S. territories were not
estimated because EPA lacked data on the annual amount of new construction acreage in these
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Section 9: Estimating Incremental Costs for the Proposed Regulation
areas. However, assuming a small amount of construction occurs in these areas, EPA expects
that these values would be low in comparison to the national costs.
The total costs of the options considered are presented in Table 9-1.
Table 9-1. Estimated Total Annual Costs of Regulatory Options
for the C&D Industry
Regulatory option
Option 1
Option 2
Option 3
Annual cost
(millions 2008 dollars)
$132
$1,891
$3,797
9.2. ANALYSIS OF STATE EQUIVALENCY
EPA analyzed state requirements to evaluate costs from this proposed rulemaking that are in
excess of costs from current state requirements. EPA did not conduct a survey of states or
municipalities to determine baseline requirements because of Paperwork Reduction Act
requirements. EPA collected and evaluated state erosion and sediment control and stormwater
permits and regulations, as well as erosion and sediment control and stormwater BMP design and
guidance manuals, from searching state Web sites. EPA specifically compiled sediment basin
requirements, soil stabilization requirements, and numeric standards for all 50 states and the
District of Columbia from these sources.
EPA performed similar analyses of state requirements as part of the 2002 and 2004 regulatory
efforts for the C&D industry. The results of the previous EPA analyses are provided in the
respective technical development documents (TDDs) supporting the 2002 proposed rule and
2004 final action (hereinafter referred to as the 2002 TDD and 2004 TDD, respectively). In 2007
EPA performed another search to update the state requirements for erosion and sediment
controls.
EPA organized all the state requirements information by its source documentation (i.e., EPA's
2007 state literature search, the 2004 TDD, and the 2002 TDD). EPA developed a revised
summary of state requirements, including sediment basin storage volume, sediment basin design
parameters, numeric standards, and soil stabilization requirements. For EPA's summary of
requirements by state, and the source documentation, see Appendix A.
Where information was not available from EPA's 2007 state literature search, EPA defaulted to
previously documented state regulation inputs/assumptions, including (in order of preference):
(1) information contained in the March 2004 Development Document for Final Action for
Effluent Guidelines and Standards for the Construction and Development Category (EPA-821-
B-04-001), and (2) information contained in the June 2002 Development Document for Proposed
Effluent Guidelines and Standards for the Construction and Development Category (EPA-821-
R-02-007). In several instances, when it was unclear how a specific state requirement was
implemented, EPA used best professional judgment to estimate the state requirement. For
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Section 9: Estimating Incremental Costs for the Proposed Regulation
example, where a state program specified the use of a sediment basin but did not specify a
sediment basin size (or other design standards that could be used to estimate sediment basin
size), it was assumed that the basin size requirement was 1,800 cubic feet per acre (cf/acre).
9.3. DEVELOPMENT OF MODEL CONSTRUCTION SITES AND SELECTION OF
INDICATOR CITIES
9.3.1. MODEL CONSTRUCTION SITES
As discussed in Section 4.2.2, EPA developed nine model projects from an analysis of NOT data.
The six sectors or construction site model projects that EPA used to represent the industry
follow:
Large Residential - median size 33 acres
Large Nonresidential - median size 51 acres
Large Transportation - median size 79 acres
Medium Residential - median size 16.7 acres
Medium Nonresidential - median size 15 acres
Medium Transportation - median size 16 acres
Small Residential - median size 3 acres
Small Nonresidential - median size 2.6 acres
Small Transportation - median size 3 acres
EPA based its costing on both the size of sediment basins needed, the annual volume of runoff
being treated, and assumptions regarding the extent of site area disturbed and the duration of land
disturbance. Table 9-2 presents a summary of EPA's model project cost assumptions.
EPA assumed for costing purposes that only 90 percent of each construction site would be
denuded and producing stormwater runoff that would require treatment. This assumption is to
account for portions of the site that do not drain to a centralized location, such as sheet flow
through a silt fence on the project perimeter. In addition, this assumption concerning the
percentage of the site that is disturbed is an attempt to account for the changing nature of
construction activities on a site over time. For example, during initial clearing and grading
activities, nearly 100 percent of the construction site could be disturbed. However, this condition
might exist for only a few weeks. Once roads, parking lots (in nonresidential projects) and
building structures are installed and soils on the site are stabilized, it is likely that stormwater
runoff from these stabilized portions of the site would be separated from stormwater from
disturbed areas of the site and diverted around sediment basins and temporary treatment systems.
Also, for many projects, it is likely that some portion of the site would not be disturbed, such as
areas maintained as green/open space, forest preservation areas, and vegetated stream buffers.
Therefore, assuming that 100 percent of the site is disturbed for the entire portion of the project
would likely result in overestimation of costs of regulatory options. A 90 percent assumption,
while still somewhat conservative, allows for an upper-bound estimate of area disturbed.
EPA assumed that all projects would be disturbed, on average, for a period of 9 months. EPA
believes that 9 months is a somewhat conservative assumption of the amount of time that these
Page 9-3
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
projects would be disturbing land. Specifically, on most smaller projects, earth-disturbing
activities and soil stabilization would likely be completed in a period of a few months.
EPA notes that these assumptions, while useful for modeling, likely vary considerably among
actual construction projects. However, because EPA lacks data on the typical duration of
disturbed soils at construction projects and the duration that treatment would need to be in place,
this modeling approach provides a reasonable, if somewhat conservative, means of estimating
runoff volumes requiring treatment and incremental compliance costs of the proposed regulation.
Table 9-2. Model Project Cost Assumptions
Project description
Large Residential
Large Nonresidential
Large Transportation
Medium Residential
Medium Nonresidential
Medium Transportation
Small Residential
Small Nonresidential
Small Transportation
Median site size
(acres)
33
51
79
16.7
15
16
3
2.6
3
% of site disturbed
90%
90%
90%
90%
90%
90%
90%
90%
90%
Duration of disturbance
(months)
9
9
9
9
9
9
9
9
9
9.3.2. ESTIMATION OF RAINFALL DEPTHS AND RUNOFF VOLUMES
To calculate sediment basin sizing under various regulatory scenarios and to determine runoff
volumes for costing treatment systems, EPA evaluated several references to determine rainfall
depths for a series of design storm return periods for one indicator city in each state (for a
discussion of this analysis, see section 3.5.3 and Appendix D). The storm depths for each
indicator city were used as point estimates for rainfall depths in each respective state. Using
these storm depths, EPA estimated runoff coefficients for each state using the process described
in TR-55 (USDA 1986). EPA estimated a runoff curve number using the Soil Conservation
Service runoff curve number equation:
Q =
where
Q = runoff (in)
P = rainfall (in)
S = potential maximum retention after runoff begins (in)
Ia = initial abstraction (in) = 0.2S
Page 9-4
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
(P-0.2S)2
(P + 0.8S)
CN
Using the values contained in TR-55 for Curve Numbers for Developing Urban Areas in Table
9-3, (from TR-55, Table 2-2a), along with the 2-year, 24-hour storm depths in Table 3-3, EPA
calculated runoff coefficients for the four hydrologic soils groups in each state for the 2-year, 24-
hour storm event. Using data on the prevalence of soils by hydrologic soil groups obtained from
STATSGO for each state (see Table 3-8), EPA then calculated a weighted runoff coefficient for
each state for the 2-year, 24-hour storm event. These results are summarized in Table 9-3 and
were used to determine the required sediment basins size for capturing runoff from the 2-year,
24-hour storm event in each state. EPA also calculated the weighted runoff coefficient for the 10-
year, 6-hour storm, which was used to estimate volumes for various alternative sediment basin
sizing requirements based on removing a specified particle size fraction. These results are
presented in Table 9-4. The rainfall analysis data is DCN 43095 and the STATSGO soils data
evaluation is DCN 43096 in the Administrative record.
9.3.3. ESTIMATION OF SEDIMENT BASIN VOLUMES AND ATS TREATMENT
VOLUMES
The runoff coefficient values, coupled with state precipitation estimates, allowed EPA to
determine sediment basin sizing for each of the model sites for various design scenarios (such as
calculating runoff from the 2-year, 24-hour storm)
For estimating average annual runoff volumes for each model site in each state, EPA multiplied
the average annual precipitation in each state by the site size and a runoff coefficient of 0.4. This
value of 0.4 was chosen as a reasonable estimate of the percent of average rainfall that would be
converted to runoff. EPA acknowledges that this approach likely overestimates runoff volumes
(and hence, volumes requiring treatment and associated treatment costs) since many smaller
storm events would not produce any, or very little, runoff. This approach also does not account
for precipitation that falls as snow. It also assumes that the entire disturbed area is in a "newly
graded areas" state, as defined by TR-55, for the entire duration of the project. In reality, site
areas during various states of the construction project would be in various states, ranging from
bare soil, to temporarily stabilized with mulch, to vegetated. As a result, curve numbers could be
much lower and associated runoff volumes could be much lower. However, this approach does
allow for a reasonable, albeit conservative, estimate of treatment volumes for determining
compliance costs. EPA multiplied the average annual runoff volumes for each model project by
0.75 to account for the assumption that each project would require treatment for 9 months, and
hence would be treating 75 percent of the average annual runoff volume. This analysis does not
account for seasonal variations in rainfall - EPA assumed that precipitation would be evenly
distributed over the year.
Page 9-5
-------
Table 9-3. State Runoff Coefficients for 2-Year, 24-Hour Storm Events
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
2-year,
24-hour
storm
depth
(inches)
4.50
1.40
4.10
2.00
2.00
3.10
3.26
4.75
3.70
1.20
2.85
2.95
3.25
3.50
3.00
5.25
2.80
3.16
3.10
2.40
2.75
4.45
3.45
1.30
3.00
1.00
2.80
Runoff
coefficient
for A soils
0.49
0.12
0.46
0.22
0.22
0.37
0.38
0.51
0.43
0.08
0.34
0.35
0.38
0.41
0.36
0.54
0.33
0.37
0.37
0.28
0.33
0.49
0.40
0.10
0.36
0.05
0.33
Runoff
coefficient
for B soils
0.67
0.31
0.64
0.42
0.42
0.56
0.58
0.68
0.62
0.25
0.54
0.55
0.58
0.60
0.55
0.70
0.53
0.57
0.56
0.48
0.53
0.66
0.60
0.28
0.55
0.20
0.53
Runoff
coefficient
for C soils
0.78
0.47
0.76
0.58
0.58
0.70
0.71
0.79
0.74
0.42
0.68
0.69
0.71
0.73
0.69
0.80
0.67
0.70
0.70
0.63
0.67
0.78
0.72
0.45
0.69
0.36
0.67
Runoff
coefficient
for D soils
0.85
0.61
0.83
0.70
0.70
0.79
0.80
0.86
0.82
0.56
0.77
0.78
0.80
0.81
0.78
0.87
0.77
0.79
0.79
0.74
0.77
0.85
0.81
0.58
0.78
0.50
0.77
%A
soils
8.7%
4.7%
0.6%
10.9%
7.2%
9.1%
20.8%
18.1%
6.6%
4.4%
1.4%
3.5%
0.9%
3.8%
0.1%
1.7%
7.7%
10.0%
23.9%
29.0%
8.3%
2.3%
1.0%
2.9%
31.9%
5.6%
17.1%
%B
soils
41.2%
38.6%
28.3%
32.2%
46.7%
41.1%
30.9%
6.3%
53.1%
46.8%
44.5%
32.6%
66.0%
58.0%
42.7%
14.4%
12.9%
38.6%
16.6%
28.7%
37.4%
32.3%
40.1%
39.5%
53.6%
26.4%
24.8%
%C
soils
28.8%
17.2%
35.9%
18.4%
24.6%
35.9%
13.4%
8.6%
16.9%
23.1%
27.0%
41.8%
11.6%
19.5%
44.9%
28.9%
43.9%
26.4%
34.4%
12.9%
15.4%
38.6%
39.8%
27.2%
3.0%
17.7%
41.4%
%D
soils
21.3%
39.5%
35.1%
38.5%
21.4%
13.9%
34.9%
67.0%
23.5%
25.7%
27.1%
22.1%
21.5%
18.7%
12.3%
55.1%
35.5%
25.0%
25.2%
29.4%
38.9%
26.9%
19.0%
30.4%
11.5%
50.3%
16.6%
Weighted
runoff
coefficient 2-
year, 24-hour
storm
0.72
0.44
0.75
0.54
0.51
0.63
0.63
0.78
0.67
0.36
0.64
0.65
0.64
0.66
0.64
0.82
0.66
0.64
0.62
0.52
0.63
0.75
0.68
0.41
0.52
0.37
0.60
-------
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of
Columbia
2-year,
24-hour
storm
depth
(inches)
3.31
1.54
2.90
3.34
1.90
2.62
3.70
2.50
3.23
3.20
3.62
2.25
3.37
3.90
1.40
2.40
3.11
2.00
2.56
2.80
1.60
3.16
Runoff
coefficient
for A soils
0.39
0.15
0.35
0.39
0.21
0.31
0.43
0.30
0.38
0.38
0.42
0.26
0.40
0.44
0.12
0.28
0.37
0.22
0.30
0.33
0.16
0.37
Runoff
coefficient
for B soils
0.58
0.34
0.54
0.59
0.41
0.51
0.62
0.50
0.58
0.57
0.61
0.46
0.59
0.63
0.31
0.48
0.56
0.42
0.50
0.53
0.35
0.57
Runoff
coefficient
for C soils
0.71
0.50
0.68
0.72
0.57
0.66
0.74
0.64
0.71
0.71
0.73
0.62
0.72
0.75
0.47
0.63
0.70
0.58
0.65
0.67
0.51
0.70
Runoff
coefficient
for D soils
0.80
0.63
0.78
0.80
0.69
0.76
0.82
0.75
0.80
0.79
0.82
0.73
0.80
0.83
0.61
0.74
0.79
0.70
0.75
0.77
0.64
0.79
%A
soils
12.5%
5.6%
9.6%
7.9%
4.7%
0.6%
6.8%
5.2%
6.0%
15.3%
11.9%
2.9%
0.1%
5.1%
5.3%
4.9%
1.7%
6.6%
7.3%
14.4%
4.5%
10.0%
%B
soils
32.8%
41.9%
18.5%
48.8%
56.1%
16.8%
44.5%
32.1%
28.4%
35.7%
41.8%
45.2%
53.6%
27.2%
36.2%
18.0%
53.7%
53.4%
21.5%
46.8%
40.5%
38.6%
%C
soils
25.1%
16.5%
51.1%
16.5%
16.6%
54.6%
22.3%
37.1%
54.2%
32.4%
19.5%
11.5%
30.4%
24.5%
16.2%
54.3%
32.3%
24.2%
54.2%
18.1%
19.5%
26.4%
%D
soils
29.6%
36.0%
20.7%
26.8%
22.6%
28.0%
26.4%
25.6%
11.5%
16.5%
26.8%
40.4%
15.9%
43.2%
42.3%
22.8%
12.3%
15.8%
17.0%
20.7%
35.5%
25.0%
Weighted
runoff
coefficient 2-
year, 24-hour
storm
0.66
0.46
0.64
0.65
0.49
0.66
0.68
0.61
0.66
0.62
0.67
0.58
0.66
0.73
0.45
0.61
0.63
0.49
0.61
0.58
0.48
0.64
era
re
-------
Table 9-4. State Runoff Coefficients for 10-Year, 6-Hour Storm Events
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
10-year,
6-hour
storm
depth
(inches)
4.60
1.57
4.35
1.70
2.30
3.25
3.44
5.25
4.20
4.80
1.20
3.30
3.12
3.54
3.90
3.09
5.75
2.90
3.32
3.30
2.70
3.10
4.70
3.85
1.10
3.52
1.29
Runoff
coefficient
for A soils
0.50
0.15
0.48
0.17
0.27
0.38
0.40
0.54
0.47
0.51
0.08
0.39
0.37
0.41
0.44
0.37
0.57
0.35
0.39
0.39
0.32
0.37
0.51
0.44
0.07
0.41
0.10
Runoff
coefficient
for B soils
0.67
0.34
0.66
0.37
0.47
0.58
0.59
0.70
0.65
0.68
0.25
0.58
0.57
0.60
0.63
0.56
0.73
0.54
0.58
0.58
0.52
0.56
0.68
0.63
0.23
0.60
0.28
Runoff
coefficient
for C soils
0.78
0.51
0.77
0.53
0.62
0.71
0.72
0.80
0.76
0.79
0.42
0.71
0.70
0.73
0.75
0.70
0.82
0.68
0.71
0.71
0.66
0.70
0.79
0.75
0.39
0.73
0.44
Runoff
coefficient
for D soils
0.85
0.64
0.84
0.66
0.73
0.80
0.81
0.87
0.84
0.86
0.56
0.80
0.79
0.81
0.83
0.79
0.88
0.78
0.80
0.80
0.76
0.79
0.85
0.83
0.53
0.81
0.58
%A
soils
8.7%
4.7%
0.6%
10.9%
7.2%
9.1%
20.8%
18.1%
6.6%
0.0%
4.4%
1.4%
3.5%
0.9%
3.8%
0.1%
1.7%
7.7%
10.0%
23.9%
29.0%
8.3%
2.3%
1.0%
2.9%
31.9%
5.6%
%B
soils
41.2%
38.6%
28.3%
32.2%
46.7%
41.1%
30.9%
6.3%
53.1%
0.0%
46.8%
44.5%
32.6%
66.0%
58.0%
42.7%
14.4%
12.9%
38.6%
16.6%
28.7%
37.4%
32.3%
40.1%
39.5%
53.6%
26.4%
%C
soils
28.8%
17.2%
35.9%
18.4%
24.6%
35.9%
13.4%
8.6%
16.9%
0.0%
23.1%
27.0%
41.8%
11.6%
19.5%
44.9%
28.9%
43.9%
26.4%
34.4%
12.9%
15.4%
38.6%
39.8%
27.2%
3.0%
17.7%
%D
soils
21.3%
39.5%
35.1%
38.5%
21.4%
13.9%
34.9%
67.0%
23.5%
0.0%
25.7%
27.1%
22.1%
21.5%
18.7%
12.3%
55.1%
35.5%
25.0%
25.2%
29.4%
38.9%
26.9%
19.0%
30.4%
11.5%
50.3%
Weighted
runoff
coefficient 10-
year, 6-hour
storm
0.73
0.48
0.76
0.49
0.55
0.64
0.65
0.79
0.70
0.00
0.36
0.67
0.66
0.66
0.68
0.65
0.83
0.67
0.65
0.64
0.55
0.66
0.76
0.71
0.36
0.57
0.45
-------
era
re
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of
Columbia
10-year,
6-hour
storm
depth
(inches)
3.20
3.55
1.77
3.10
3.54
2.50
2.80
4.25
2.90
3.38
3.40
3.85
2.75
3.31
4.55
1.27
2.70
3.29
1.40
2.56
3.15
1.90
Runoff
coefficient
for A soils
0.38
0.41
0.19
0.37
0.41
0.30
0.33
0.47
0.35
0.40
0.40
0.44
0.33
0.39
0.49
0.10
0.32
0.39
0.12
0.30
0.37
0.21
Runoff
coefficient
for B soils
0.57
0.60
0.38
0.56
0.60
0.50
0.53
0.65
0.54
0.59
0.59
0.63
0.53
0.58
0.67
0.27
0.52
0.58
0.31
0.50
0.57
0.41
Runoff
coefficient
for C soils
0.71
0.73
0.55
0.70
0.73
0.64
0.67
0.77
0.68
0.72
0.72
0.75
0.67
0.71
0.78
0.44
0.66
0.71
0.47
0.65
0.70
0.57
Runoff
coefficient
for D soils
0.79
0.81
0.67
0.79
0.81
0.75
0.77
0.84
0.78
0.80
0.81
0.83
0.77
0.80
0.85
0.58
0.76
0.80
0.61
0.75
0.79
0.69
%A
soils
17.1%
12.5%
5.6%
9.6%
7.9%
4.7%
0.6%
6.8%
5.2%
6.0%
15.3%
11.9%
2.9%
0.1%
5.1%
5.3%
4.9%
1.7%
6.6%
7.3%
14.4%
4.5%
%B
soils
24.8%
32.8%
41.9%
18.5%
48.8%
56.1%
16.8%
44.5%
32.1%
28.4%
35.7%
41.8%
45.2%
53.6%
27.2%
36.2%
18.0%
53.7%
53.4%
21.5%
46.8%
40.5%
%C
soils
41.4%
25.1%
16.5%
51.1%
16.5%
16.6%
54.6%
22.3%
37.1%
54.2%
32.4%
19.5%
11.5%
30.4%
24.5%
16.2%
54.3%
32.3%
24.2%
54.2%
18.1%
19.5%
%D
soils
16.6%
29.6%
36.0%
20.7%
26.8%
22.6%
28.0%
26.4%
25.6%
11.5%
16.5%
26.8%
40.4%
15.9%
43.2%
42.3%
22.8%
12.3%
15.8%
17.0%
20.7%
35.5%
Weighted
runoff
coefficient 10-
year, 6-hour
storm
0.63
0.67
0.50
0.66
0.66
0.57
0.67
0.72
0.64
0.67
0.64
0.68
0.63
0.66
0.77
0.42
0.64
0.65
0.38
0.61
0.61
0.53
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
For each state, EPA calculated sediment basin sizes on the basis of the following sizing criteria:
3,600 cubic feet per acre (cf/acre)
Runoff from the 2-year, 24-hour storm
Removal of a design particle size
The 3,600 cf/acre criteria is a requirement in the EPA Construction General Permit for
construction sites with a common drainage area of 10 or more disturbed acres. Calculation of
required basin size is simply based on the size of the disturbed area of the site draining to the
basin.
To determine the size for a basin designed to capture runoff from the 2-year, 24-hour storm, EPA
calculated the runoff coefficient for one indicator city in each state for the 2-year, 24-hour storm
event (see Table 9-5). By multiplying these runoff coefficients by the associated 2-year, 24-hour
storm depth and the site size, EPA calculated the basin size required in each state for each model
project.
For the design particle size standard, EPA used an approach outlined in the California
Stormwater Quality Association's (CSQA's) Stormwater BMP Handbook: Construction
(http://www.cabmphandbooks.com/Construction.asp) (CSQA 2003) to calculate sediment basin
sizes required to remove particles of 10, 15 and 20 microns. EPA based these calculations on the
average 10-year, 6-hour storm event intensity. The intensity (in inches per hour) was determined
by dividing the 10-year, 6-hour storm depth (see Table 3-3) by the storm duration (6 hours).
The approach contained in the CSQA handbook is based on the settling velocity of particles as
determined by Stokes' Law, which states that the settling velocity (Vc) is a function of the
density of the particle (ps) and the fluid (pf), the acceleration due to gravity (g\ the diameter of
the particle (d) and the dynamic viscosity of the fluid (ju).
g(ps-pf)d2
18//
Stokes' Law is generally valid for Reynolds numbers less than 1 (quiescent conditions) and for
spherical particles.
Once the settling velocity of the design particle size is determined (called the terminal settling
velocity), sediment basins can be sized so that all particles with a settling velocity equal to or
greater than the terminal velocity can be removed. This is accomplished by calculating the
surface area (^4) of the basin for a specified flow rate (Q) using the following equation:
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Section 9: Estimating Incremental Costs for the Proposed Regulation
The approach in the CSQA handbook uses a site-specific soil grain size determined using a wet
sieve analysis for determining the terminal settling velocity, and the design flowrate is based on
the 10 year, 6-hour rainfall event. The option described in this handbook is illustrated in Figure
9-1.
Sediment basin(s) shall be designed using the standard equation:
As=1.2Q/Vs
Where:
As = Minimum surface area for trapping soil particles of a certain size
Vs = Settling velocity of the design particle size chosen
Q = CIA
Where
Q = Discharge rate measured in cubic feet per second
C = Runoff coefficient
I = Precipitation intensity for the 10-year, 6-hour rain event in inches per hour
A = Area draining into the sediment basin in acres
The design particle size shall be the smallest soil grain size determined by wet sieve analysis, or
the fine silt sized (0.01 mm [or 0.0004 in.]) particle, and the Vs used shall be 100 percent of the
calculated settling velocity.
Figure 9-1. CSQA Settling Velocity Criteria for Sizing Sediment Basins
Using the CSQA approach, EPA calculated sediment basin sizes required to remove 100 percent
of particles larger than 10, 15, and 20 microns in each state based on the 10-year, 6-hour storm
intensity. EPA used a particle density of 2,650 kg/m3, and the density and viscosity of water at
20 degrees Celsius (°C) (pf =998.2 kg/m3, \i = 0.001 N-S/m3). Values for C were taken from
Table 9-4.
Table 9-5 presents estimates of sediment basin sizing used for each state for the options
considered. This table also contains the basin size EPA used for baseline calculations. For Option
1, EPA evaluated sediment basin sizes of 3,600 cf/acre.
Table 9-6 summarizes the treatment volumes for each state for each of the nine model projects.
For the active treatment system (ATS) options, EPA also calculated storage requirements for
runoff from the 2-year, 24-hour storm. Where this value was greater than the sediment basin
sizing requirements under a given state's baseline sediment basin sizing, EPA calculated
additional costs to provide the incremental storage volume for the 2-year, 24-hour storm over
baseline.
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Section 9: Estimating Incremental Costs for the Proposed Regulation
Table 9-5. Sediment Basin Sizes for States
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Baseline sediment
basin size
(cf/acre)
1,800
3,600
3,600
3,660
1,800
3,600
3,600
3,600
1,800
12,868
3,600
6,494
1,800
3,600
3,600
3,600
3,600
3,600
3,600
7,307
3,600
6,172
3,600
3,600
1,800
1,800
3,600
6,333
1,800
3,600
3,600
1,800
3,600
1,800
9,296
3,600
5,000
1,800
13,168
3,600
8,196
9,969
3,600
1,800
2-year, 24-hour runoff
sediment basin size
(cf/acre)
11,798
2,254
11,179
3,898
3,685
7,043
7,487
13,371
9,019
~
1,585
6,591
6,968
7,536
8,337
7,004
15,638
6,744
7,353
6,977
4,530
6,247
12,147
8,574
1,948
5,680
1,350
6,064
7,886
2,570
6,776
7,884
3,361
6,261
9,184
5,495
7,754
7,239
8,756
4,745
8,095
10,403
2,284
5,345
20-micron
basin size
(cf/acre)
3,382
709
3,326
929
1,188
2,071
2,216
4,145
2,871
~
445
2,141
2,067
2,302
2,605
2,023
4,804
1,959
2,167
2,083
1,429
1,975
3,598
2,684
462
1,869
488
1,944
2,372
828
2,032
2,344
1,240
1,877
2,959
1,788
2,276
2,157
2,612
1,626
2,230
3,404
581
1,687
15-micron
basin size
(cf/acre)
6,013
1,260
5,914
1,652
2,113
3,681
3,939
7,368
5,104
~
790
3,805
3,674
4,093
4,632
3,597
8,540
3,483
3,852
3,703
2,541
3,511
6,397
4,771
822
3,323
868
3,456
4,217
1,473
3,612
4,167
2,205
3,336
5,260
3,178
4,046
3,835
4,643
2,891
3,964
6,051
1,033
2,998
10-micron
basin size
(cf/acre)
13,530
2,836
13,306
3,717
4,754
8,283
8,863
16,579
11,485
~
1,778
8,562
8,267
9,208
10,422
8,094
19,215
7,836
8,667
8,332
5,717
7,901
14,393
10,734
1,849
7,476
1,953
7,775
9,489
3,313
8,126
9,375
4,962
7,507
11,835
7,151
9,103
8,628
10,447
6,506
8,920
13,615
2,324
6,746
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Section 9: Estimating Incremental Costs for the Proposed Regulation
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
Baseline sediment
basin size
(cf/acre)
3,600
3,600
3,600
2,770
1,800
1,800
7,503
2-year, 24-hour runoff
sediment basin size
(cf/acre)
7,141
3,575
5,679
5,884
2,770
~
7,353
20-micron
basin size
(cf/acre)
2,119
702
1,593
1,857
923
~
2,167
15-micron
basin size
(cf/acre)
3,767
1,248
2,832
3,301
1,640
~
3,852
10-micron
basin size
(cf/acre)
8,475
2,808
6,371
7,426
3,690
~
8,667
9.4. ESTIMATION OF COSTS
EPA estimated costs for the three options using two costing elements: sediment basins costs and
treatment costs. The components of the estimated costs are discussed below.
9.4.1. COMPONENTS OF COST
The components of the capital and annual costs and the terminology used in developing these
costs are presented below. Section 7 discusses costs of individual BMPs not directly used to
estimate compliance costs for the proposed regulations.
9.4.1.1. Capital Costs
The capital costs consist of two major components: direct capital costs and indirect capital costs.
The direct capital costs include the following:
Purchased equipment cost, including ancillary equipment (e.g., piping, valves,
controllers);
Delivery cost; and
Installation/construction cost (including labor and site work).
Indirect capital costs consist of engineering, contingency, contractor fees, and the like. These
costs together with the direct capital costs form the total capital investment. Indirect costs are
often estimated as a percentage of the total direct capital cost.
Page 9-13
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Table 9-6. Model Project Treatment Volumes (million gallons)
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New
Hampshire
New Jersey
New Mexico
Small
Residential
1.077
0.170
1.046
0.404
0.292
0.976
0.945
1.362
1.117
0.402
0.249
0.726
0.872
0.696
0.806
0.989
1.291
0.915
0.929
0.932
0.665
0.632
1.153
0.807
0.259
0.622
0.084
0.884
1.033
0.340
Nonresidential
0.935
0.148
0.908
0.351
0.254
0.847
0.820
1.182
0.969
0.349
0.216
0.630
0.756
0.604
0.699
0.858
1.120
0.794
0.806
0.808
0.577
0.548
1.000
0.700
0.225
0.540
0.073
0.767
0.896
0.295
Transportation
1.079
0.170
1.047
0.405
0.293
0.977
0.946
1.364
1.119
0.402
0.249
0.727
0.873
0.696
0.807
0.990
1.293
0.916
0.930
0.933
0.666
0.632
1.154
0.808
0.259
0.623
0.084
0.885
1.034
0.340
Medium
Residential
6.004
0.948
5.830
2.252
1.629
5.438
5.267
7.592
6.226
2.239
1.388
4.046
4.859
3.877
4.491
5.511
7.196
5.101
5.177
5.192
3.708
3.521
6.425
4.497
1.442
3.467
0.468
4.925
5.754
1.892
Nonresidential
5.393
0.851
5.237
2.023
1.463
4.884
4.731
6.819
5.593
2.011
1.246
3.634
4.364
3.482
4.034
4.950
6.463
4.582
4.650
4.663
3.330
3.162
5.771
4.039
1.295
3.114
0.420
4.424
5.168
1.700
Transportation
5.752
0.908
5.586
2.157
1.561
5.210
5.046
7.274
5.965
2.145
1.330
3.876
4.655
3.714
4.303
5.280
6.894
4.887
4.960
4.974
3.552
3.373
6.156
4.308
1.382
3.321
0.448
4.719
5.513
1.813
Large
Residential
11.864
1.872
11.520
4.450
3.220
10.745
10.408
15.003
12.304
4.425
2.742
7.994
9.601
7.660
8.875
10.890
14.219
10.080
10.230
10.259
7.326
6.957
12.696
8.886
2.850
6.850
0.924
9.732
11.370
3.739
Nonresidential
18.335
2.894
17.804
6.877
4.976
16.606
16.086
23.186
19.015
6.838
4.238
12.355
14.838
11.838
13.716
16.830
21.975
15.579
15.809
15.855
11.322
10.752
19.621
13.733
4.404
10.587
1.428
15.041
17.571
5.779
Transportation
28.366
4.477
27.544
10.639
7.698
25.691
24.885
35.870
29.417
10.579
6.556
19.113
22.955
18.315
21.220
26.037
33.996
24.101
24.458
24.528
17.516
16.633
30.355
21.245
6.814
16.378
2.209
23.269
27.184
8.941
-------
era
re
in
New York
North
Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South
Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
Small
Residential
0.811
0.949
0.353
0.830
0.721
0.895
0.914
0.983
0.999
0.354
1.013
0.715
0.320
0.747
0.887
0.775
0.941
0.691
0.324
1.115
0.917
Nonresidential
0.704
0.823
0.307
0.720
0.625
0.776
0.793
0.853
0.866
0.307
0.879
0.620
0.277
0.648
0.769
0.672
0.816
0.600
0.281
0.968
0.796
Transportation
0.812
0.950
0.354
0.831
0.722
0.896
0.915
0.984
1.000
0.354
1.014
0.715
0.320
0.748
0.887
0.776
0.942
0.692
0.324
1.116
0.918
Medium
Residential
4.519
5.288
1.969
4.626
4.018
4.985
5.095
5.478
5.565
1.971
5.645
3.982
1.782
4.163
4.940
4.317
5.243
3.853
1.804
6.215
5.110
Nonresidential
4.059
4.749
1.769
4.156
3.609
4.478
4.576
4.920
4.998
1.770
5.071
3.576
1.601
3.739
4.437
3.878
4.709
3.461
1.620
5.582
4.590
Transportation
4.329
5.066
1.887
4.433
3.849
4.777
4.881
5.248
5.331
1.888
5.409
3.815
1.708
3.989
4.733
4.136
5.023
3.692
1.728
5.954
4.896
Large
Residential
8.929
10.449
3.892
9.142
7.939
9.852
10.068
10.824
10.996
3.894
11.155
7.868
3.522
8.226
9.762
8.531
10.360
7.614
3.565
12.280
10.098
Nonresidential
13.800
16.148
6.015
14.129
12.269
15.225
15.560
16.729
16.994
6.018
17.240
12.160
5.443
12.714
15.087
13.184
16.011
11.767
5.509
18.979
15.606
Transportation
21.350
24.982
9.305
21.858
18.981
23.554
24.072
25.880
26.291
9.310
26.671
18.812
8.421
19.669
23.341
20.396
24.770
18.204
8.523
29.361
24.144
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Section 9: Estimating Incremental Costs for the Proposed Regulation
9.4.1.2. Annual Costs
As with capital costs, the annual costs have both a direct and an indirect component, and include
the following:
Raw material costs - chemicals and other materials used in the treatment processes
(e.g., chitosan, polymers);
Operating labor and material costs - the labor and materials directly associated with
operation of the process equipment;
Maintenance labor and material costs - the labor and materials required for repair and
routine maintenance of the equipment;
Rental equipment costs;
Energy costs - calculated on the basis of total energy requirements; and
Waste disposal - recurring waste disposal costs (e.g., filtration media replacement).
Indirect annual costs include monitoring, taxes, insurance, and amortization. Monitoring is the
periodic analysis of wastewater effluent samples to ensure that discharge limitations are being
met.
9.4.1.3. Total Project Cost
EPA calculated total project cost from the C&D Cost Spreadsheet Model. The Agency assumed
a duration of 9 months for each model project.
9.4.2. BASELINE AND INCREMENTAL COSTS
EPA estimated the costs for the current sediment basins at each model site (baseline) on the basis
of the state requirements analysis. The C&D Cost Spreadsheet Model uses baseline costs to
determine the incremental costs attributable to each regulatory option.
EPA calculated incremental costs as the difference between baseline and post-compliance costs,
using the following equation:
Total CoStSlncremental = Total CoStSQption - Total CoStSBaseline
For example, if a state specified a design basin size of 3,600 cf/acre (baseline) and an EPA
Option specified 3,600 cf/acre (Option 1), the incremental cost for Option 1 in that state would
be zero. If the option cost exceeds the baseline cost, only the cost exceeding the baseline cost is
incremental. If the baseline cost exceeds the option cost, there is no incremental cost.
Page 9-16
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Section 9: Estimating Incremental Costs for the Proposed Regulation
9.4.3. SOURCES AND STANDARDIZATION OF COST DATA
EPA used literature values for sediment basin costs and vendor data for the chemical-enhanced
filtration numeric standard costs (see Sections 3.2 and 3.5.5).
Capital and annual cost data were standardized to 2008 dollars on the basis of the Engineering
News-Record (ENR) Construction Cost Index (CCI). The sediment basin cost reference used by
EPA was based on a study completed in 1989. The ENR CCI in 1989 was 4,615 and the value in
February of 2008 was 8,084. EPA adjusted sediment basin costs obtained in 1989 dollars to 2008
dollars by increasing costs by 57 percent (8084/4615 = 1.57). Vendor data was obtained early in
the year 2008 so no standardization was necessary to arrive at year 2008 costs.
9.4.4. C&D COST SPREADSHEET MODEL
EPA developed a cost spreadsheet model to estimate compliance costs for the C&D technology
options, taking into account existing sediment basin requirements specified by states. Table 9-7
presents descriptions for each individual worksheet included in the C&D Cost Spreadsheet
Model.
Table 9-7. C&D Cost Spreadsheet Model Worksheets
Worksheet
NLCD Data
Project Distribution
State Projects
Option Parameters
Cost Inputs
Settling Velocity defaults
Baseline Calcs
Key Equations
Small Residential
Medium Residential
Large Residential
Large Residential
Small Nonresidential
Medium Nonresidential
Large Nonresidential
Description
National Land Cover Data (NLCD). Shows acres developed and changes in
developed acres by state. An Annual Rate of Development, NLCD 1992 -
2001 (acres) is calculated and used in the "State Projects" worksheet to
estimate acres by model site by state.
Presents the median site size in acres for each model project and the
distribution of projects by project type, based on an analysis of NOI data.
Number of acres/projects by model site by state.
Contains key input parameters for costing options (i.e., baseline and option
sediment basin sizes, as well as annual precipitation data, which is the basis
for calculating runoff volumes for the turbidity standard options).
Cost assumptions for sediment basin costs.
Presents constants and non-state-specific settling velocity calculations.
Calculations for alternate sediment basin baseline calculations (California,
New York, Washington, and Wisconsin). Updates the alternate baseline
calculations in the Option Parameters worksheet - Sediment Basin Sizing
(alternate cf/acre) column.
Provides key equations and defines variables (Rational Equation, Stokes'
Law, and Cost Indices).
For each model project site type, presents baseline and option costs, as well
as option costs incremental to baseline.
Page 9-17
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Section 9: Estimating Incremental Costs for the Proposed Regulation
Worksheet
Small Transportation
Medium Transportation
Large Transportation
Final Option 1
Final Option 2
Final Option 3
Size Cutoffs
Clay Content
R Cutoffs
Runoff Coefficients
Design Storms
HSG
Summary
Description
Summarizes incremental costs by option.
Presents data on distribution of projects by project sizes as a basis for
determining acres in-scope for site size cutoffs greater than 10 acres
Presents percent of acres in various percent clay content fractions based on
national soils GIS data
Presents estimates of the % of acres within various R-factor categories and
the number of projects subject to Option 2 requirements.
Contains calculations for determining state-specific curve numbers
Presents data on various design storms for indicator cities
Presents state hydrologic soil group estimates based on national soils GIS
data.
Presents summaries of state and national costs by option.
9.4.5. ESTIMATION OF COSTS FOR SEDIMENT TRAPS AND BASINS
Descriptions of sediment traps and basins, including design criteria, performance, and costs, are
described in detail in Sections 7.2.3. This section describes EPA's rationale in selecting costs for
sediment basins and traps.
9.4.5.1. Sediment Basin and Trap Cost Similarities
Sediment basins and traps are generally similar in design but have several significant differences.
Sediment basins are usually viewed as a final attempt to treat stormwater runoff before
discharging and are also often modified near the end of the construction period to serve as post-
construction stormwater runoff controls. Sediment basins are typically used for larger drainage
areas than sediment traps. Sediment basins usually are larger in size and use a semi-permanent
outlet structure (e.g., perforated riser pipe). Sediment traps on the other hand, are typically small,
temporary structures used for detaining sediment-laden runoff from smaller drainage areas. Note
that EPA used the terminology sediment trap for sites smaller than 10 acres and sediment basin
for sites larger than 10 acres (EPA's smallest modeled project sizes are approximately 3 acres).
Because none of EPA's options contain requirements for sites smaller than 10 acres to install
sediment traps of any particular size, EPA did not estimate any incremental compliance costs for
sites smaller than 10 acres.
9.4.5.2. Temporary Sediment Basin Construction Costs
EPA 1993 referenced the Southeastern Wisconsin Regional Planning Commission's 1991 Costs
of Urban Nonpoint Source Water Pollution Control Measures (SWRPC 1991) for estimating
costs of temporary sediment basins. Costs include site preparation (e.g., grading, excavation,
place and compact fill), site development (e.g., riprap, temporary basin inlet and outlet
Page 9-18
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Section 9: Estimating Incremental Costs for the Proposed Regulation
structures), and contingencies. Temporary basins are a generally less expensive option as
compared to permanent basins (e.g., SWRPC assumed temporary basin inlet and outlet costs to
be one-half of permanent detention basin inlet and outlet costs). Table 9-8 summarizes the cost
data EPA used for estimating sediment basin costs. EPA used the average value of $0.30 per
cubic foot of storage for calculating incremental costs for sediment basins and for storage
volumes required for ATS. EPA adjusted all sediment basin costs from 1989 dollars to 2008
dollars.
Table 9-8. Sediment Basin Construction Cost Data
Cost data source
USEPA (1993), original reference
is SWRPC (1991). Numerous
sources reference this data. Many
of these sources adjusted USEPA
(1993) to other basis years.
Cost
$0.10 to $0.40 per cubic foot
of storage, average of $0.30.
Basin size range
of validity
12,000 ft3 to
195,000 ft3
SWRPC (1991)
Basis year
1989
9.4.5.3. Sediment Basin Annual Operation and Maintenance (O&M) Costs
EPA 1993 estimates annual O&M costs for temporary sediment basins (associated with runoff
from active construction sites) as 25 percent of construction costs. EPA used this value to
estimate annual O&M costs for sediment basins.
9.4.6. ACTIVE TREATMENT SYSTEMS
EPA obtained ATS costs from three vendors. Two of the vendors (Clear Water and Storm Klear)
provided cost data on a dollars per gallon basis, which included consideration of all associated
costs (equipment rental, treatment chemicals, labor, and O&M). A third vendor, Clear Creek,
provided base equipment rental costs as well as a cost per gallon for treatment chemicals and a
cost per gallon for labor. EPA also collected several references that contained example project
information. Vendors stated that ATS typically cost between $0.01 and $0.03 per gallon treated,
and the case studies in the literature generally confirmed these values.
EPA elected to use a value of $0.02 per gallon to estimate ATS costs. For each of the model
construction sites in each state, EPA estimated annual volumes of runoff by multiplying average
annual precipitation by the runoff coefficient calculated for each state (see Table 9-7). By
applying the ATS cost of $0.02 per gallon, EPA estimated the costs of employing ATS for each
of the nine model projects in each state.
EPA recognizes that the use of ATSs will require storage and pretreatment of captured
stormwater runoff from a site; therefore, in evaluating ATS costs, EPA assumed that storage
would be required on-site for pretreatment and for temporary storage before treatment. Options 2
and 3 require treating all runoff produced by the 2-year, 24-hour storm. EPA determined the
amount of storage necessary to hold runoff from the 2-year, 24-hour storm for each model site in
each state. By comparing to existing state sediment basin requirements, EPA was able to
determine any additional storage volumes in each state needed to provide the required 2-yer, 24-
Page 9-19
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
hour storage under Options 2 and 3. EPA used the sediment basin cost information in Table 9-8
to estimate storage costs for Options 2 and 3. EPA updated storage costs to year 2008 dollars.
Tables 9-9 through 9-14 summarize the ATS costs per project for each of the six model projects
in each state. These tables also include incremental costs for storage (adjusted to year 2008
dollars). EPA did not estimate ATS costs for the three small model projects, because none of
EPA's options would require these sites to meet a numeric turbidity limit.
Table 9-9. ATS Costs for Large Residential Model Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
ATS cost
$237,281
$37,447
$230,406
$88,991
$64,391
$214,903
$208,168
$300,057
$246,073
$88,497
$54,843
$159,885
$192,023
$153,203
$177,507
$217,800
$284,379
$201,606
$204,593
$205,177
$146,526
$139,139
$253,919
$177,716
$56,995
$137,003
$18,477
$194,647
$227,393
$74,788
$178,589
$208,974
$77,836
$182,843
$158,777
$197,031
Storage volume
over baseline
(cubic feet)
329,934
~
250,107
5,981
62,205
113,619
128,271
322,443
238,227
~
~
170,544
129,888
156,321
112,332
397,254
103,752
123,849
30,690
~
282,051
164,142
4,884
128,040
~
~
200,838
~
104,808
200,772
~
147,213
~
62,535
Storage cost
$217,003
$164,499
$3,934
$40,913
$74,729
$84,366
$212,076
$156,685
~
~
~
$112,169
$85,429
$102,815
$73,882
$261,280
$68,239
$81,457
~
$20,185
~
$185,509
$107,959
$3,212
$84,214
~
$132,094
$68,934
$132,051
~
$96,824
~
$41,130
Total cost per
project
$454,283
$37,447
$394,905
$92,925
$105,305
$289,632
$292,533
$512,133
$402,758
$88,497
$54,843
$159,885
$304,192
$238,633
$280,321
$291,683
$545,659
$269,845
$286,051
$205,177
$166,711
$139,139
$439,428
$285,675
$60,207
$221,217
$18,477
$194,647
$359,487
$74,788
$247,523
$341,025
$77,836
$279,667
$158,777
$238,161
Page 9-20
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$201,361
$216,489
$219,921
$77,879
$223,102
$157,362
$70,438
$164,530
$195,247
$170,615
$207,204
$152,275
$71,298
$245,605
$201,966
Storage volume
over baseline
(cubic feet)
90,882
179,487
~
37,785
~
~
~
116,985
116,853
~
68,607
109,230
32,010
~
~
Storage cost
$59,774
$118,051
~
$24,852
~
~
~
$76,943
$76,856
~
$45,124
$71,842
$21,053
~
~
Total cost per
project
$261,135
$334,540
$219,921
$102,731
$223,102
$157,362
$70,438
$241,473
$272,103
$170,615
$252,328
$224,117
$92,351
$245,605
$201,966
Table 9-10. ATS Costs for Medium Residential Model Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
ATS cost
$120,078
$18,950
$116,599
$45,035
$32,586
$108,754
$105,345
$151,847
$124,528
$44,785
$27,754
$80,911
$97,175
$77,530
$89,829
$110,220
$143,913
$102,025
$103,537
$103,832
$74,151
$70,413
$128,498
$89,935
Storage volume
over baseline
(cubic feet)
166,967
~
126,569
3,027
31,480
57,498
64,913
163,176
120,557
~
~
86,306
65,731
79,108
56,847
201,035
52,505
62,675
15,531
~
142,735
83,066
Storage cost
$109,816
~
$83,247
$1,991
$20,705
$37,817
$42,694
$107,323
$79,292
~
~
~
$56,764
$43,232
$52,030
$37,389
$132,223
$34,533
$41,222
~
$10,215
~
$93,879
$54,634
Total cost per
project
$229,895
$18,950
$199,846
$47,026
$53,290
$146,571
$148,040
$259,170
$203,820
$44,785
$27,754
$80,911
$153,940
$120,763
$141,860
$147,609
$276,136
$136,558
$144,759
$103,832
$84,366
$70,413
$222,377
$144,569
Page 9-21
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$28,843
$69,332
$9,351
$98,503
$115,074
$37,847
$90,377
$105,753
$39,390
$92,529
$80,351
$99,710
$101,901
$109,556
$111,293
$39,412
$112,903
$79,635
$35,646
$83,262
$98,807
$86,341
$104,858
$77,060
$36,081
$124,291
$102,207
Storage volume
over baseline
(cubic feet)
2,472
64,796
~
101,636
~
53,039
101,603
~
74,499
~
31,647
45,992
90,831
~
19,122
~
~
~
59,202
59,135
~
34,719
55,277
16,199
~
~
Storage cost
$1,626
$42,617
~
~
$66,848
~
$34,885
$66,826
~
$48,999
~
$20,814
$30,249
$59,741
~
$12,576
~
~
~
$38,938
$38,894
~
$22,835
$36,357
$10,654
~
~
Total cost per
project
$30,469
$111,949
$9,351
$98,503
$181,922
$37,847
$125,262
$172,579
$39,390
$141,528
$80,351
$120,524
$132,150
$169,297
$111,293
$51,988
$112,903
$79,635
$35,646
$122,200
$137,701
$86,341
$127,693
$113,417
$46,735
$124,291
$102,207
Table 9-11. ATS Costs for Large Nonresidential Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
ATS cost
$366,707
$57,872
$356,082
$137,532
$99,514
$332,122
$321,714
$463,724
$380,294
$136,768
$84,757
Storage volume
over baseline
(cubic feet)
509,898
386,529
9,244
96,135
175,593
198,237
498,321
368,169
~
Storage cost
$335,368
~
$254,226
$6,080
$63,229
$115,490
$130,383
$327,753
$242,150
~
~
Total cost per
project
$702,074
$57,872
$610,308
$143,612
$162,743
$447,612
$452,097
$791,478
$622,445
$136,768
$84,757
Page 9-22
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$247,095
$296,763
$236,769
$274,328
$336,600
$439,494
$311,572
$316,190
$317,091
$226,449
$215,034
$392,420
$274,653
$88,084
$211,731
$28,556
$300,817
$351,425
$115,582
$276,002
$322,960
$120,292
$282,575
$245,383
$304,503
$311,194
$334,573
$339,877
$120,359
$344,795
$243,196
$108,858
$254,273
$301,745
$263,677
$320,224
$235,334
$110,187
$379,572
$312,129
Storage volume
over baseline
(cubic feet)
~
263,568
200,736
241,587
173,604
613,938
160,344
191,403
~
47,430
~
435,897
253,674
7,548
197,880
~
310,386
161,976
310,284
227,511
96,645
140,454
277,389
~
58,395
~
180,795
180,591
106,029
168,810
49,470
~
~
Storage cost
~
$173,353
$132,027
$158,895
$114,182
$403,796
$105,461
$125,889
~
$31,195
~
$286,696
$166,845
$4,964
$130,149
~
$204,146
~
$106,534
$204,078
~
$149,637
~
$63,565
$92,379
$182,443
~
$38,407
~
~
~
$118,912
$118,777
~
$69,737
$111,029
$32,537
~
~
Total cost per
project
$247,095
$470,116
$368,796
$433,224
$450,782
$843,291
$417,033
$442,079
$317,091
$257,644
$215,034
$679,116
$441,498
$93,048
$341,880
$28,556
$300,817
$555,570
$115,582
$382,536
$527,038
$120,292
$432,212
$245,383
$368,068
$403,572
$517,016
$339,877
$158,766
$344,795
$243,196
$108,858
$373,185
$420,523
$263,677
$389,961
$346,363
$142,724
$379,572
$312,129
Page 9-23
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Table 9-12. ATS Costs for Medium Nonresidential Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
ATS cost
$107,855
$17,021
$104,730
$40,451
$29,269
$97,683
$94,622
$136,390
$111,851
$40,226
$24,928
$72,675
$87,283
$69,638
$80,685
$99,000
$129,263
$91,639
$92,997
$93,262
$66,603
$63,245
$115,418
$80,780
$25,907
$62,274
$8,399
$88,476
$103,360
$33,995
$81,177
$94,988
$35,380
$83,110
$72,171
$89,560
$91,528
$98,404
$99,964
$35,400
$101,410
$71,528
$32,017
$74,786
Storage volume
over baseline
(cubic feet)
149,970
113,685
2,719
28,275
51,645
58,305
146,565
108,285
~
~
77,520
59,040
71,055
51,060
180,570
47,160
56,295
13,950
128,205
74,610
2,220
58,200
~
91,290
47,640
91,260
~
66,915
28,425
41,310
81,585
~
17,175
~
~
53,175
Storage cost
$98,638
~
$74,772
$1,788
$18,597
$33,968
$38,348
$96,398
$71,221
~
~
~
$50,986
$38,831
$46,734
$33,583
$118,764
$31,018
$37,026
~
$9,175
~
$84,322
$49,072
$1,460
$38,279
~
~
$60,043
~
$31,334
$60,023
~
$44,011
~
$18,696
$27,170
$53,660
~
$11,296
~
~
~
$34,974
Total cost per
project
$206,492
$17,021
$179,502
$42,239
$47,866
$131,651
$132,970
$232,788
$183,072
$40,226
$24,928
$72,675
$138,269
$108,469
$127,419
$132,583
$248,027
$122,657
$130,023
$93,262
$75,778
$63,245
$199,740
$129,852
$27,367
$100,553
$8,399
$88,476
$163,403
$33,995
$112,511
$155,011
$35,380
$127,121
$72,171
$108,255
$118,698
$152,064
$99,964
$46,696
$101,410
$71,528
$32,017
$109,760
Page 9-24
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$88,749
$77,552
$94,184
$69,216
$32,408
$111,639
$91,803
Storage volume
over baseline
(cubic feet)
53,115
31,185
49,650
14,550
~
~
Storage cost
$34,935
~
$20,511
$32,656
$9,570
~
~
Total cost per
project
$123,683
$77,552
$114,694
$101,871
$41,978
$111,639
$91,803
Table 9-13. ATS Costs for Large Transportation Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
ATS cost
$567,317
$89,531
$550,880
$212,770
$153,954
$513,813
$497,710
$717,409
$588,338
$211,589
$131,124
$382,270
$459,110
$366,295
$424,402
$520,740
$679,924
$482,021
$489,164
$490,559
$350,330
$332,670
$607,097
$424,904
$136,270
$327,561
$44,178
$465,382
$543,675
$178,812
$426,991
Storage volume
over baseline
(cubic feet)
788,842
~
597,983
14,301
148,727
271,653
306,684
770,932
569,579
~
~
~
407,755
310,550
373,749
268,576
949,798
248,062
296,112
~
73,377
~
674,358
392,449
11,677
306,132
~
~
480,185
~
250,586
Storage cost
$518,833
$393,302
$9,406
$97,820
$178,670
$201,711
$507,054
$374,621
~
$268,187
$204,254
$245,821
$176,646
$624,697
$163,154
$194,757
~
$48,261
$443,536
$258,119
$7,680
$201,348
$315,825
$164,814
Total cost per
project
$1,086,150
$89,531
$944,183
$222,176
$251,774
$692,483
$699,421
$1,224,462
$962,958
$211,589
$131,124
$382,270
$727,296
$570,549
$670,223
$697,387
$1,304,620
$645,174
$683,922
$490,559
$398,591
$332,670
$1,050,633
$683,023
$143,951
$528,909
$44,178
$465,382
$859,500
$178,812
$591,806
Page 9-25
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$499,638
$186,098
$437,160
$379,622
$471,084
$481,435
$517,605
$525,810
$186,202
$533,418
$376,238
$168,410
$393,376
$466,818
$407,925
$495,405
$364,076
$170,466
$587,220
$482,882
Storage volume
over baseline
(cubic feet)
480,028
~
351,973
~
149,516
217,291
429,137
~
90,341
~
~
~
279,701
279,385
~
164,033
261,159
76,533
~
~
Storage cost
$315,721
$231,498
$98,339
$142,915
$282,250
~
$59,418
~
~
$183,963
$183,756
~
$107,887
$171,768
$50,337
~
Total cost per
project
$815,359
$186,098
$668,658
$379,622
$569,422
$624,350
$799,855
$525,810
$245,621
$533,418
$376,238
$168,410
$577,339
$650,573
$407,925
$603,292
$535,844
$220,803
$587,220
$482,882
Table 9-14. ATS Costs for Medium Transportation Projects
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
ATS cost
$115,045
$18,156
$111,712
$43,147
$31,220
$104,195
$100,930
$145,482
$119,308
$42,908
$26,590
$77,520
$93,102
$74,280
$86,064
$105,600
$137,881
$97,748
$99,197
$99,480
Storage volume
over baseline
(cubic feet)
159,968
~
121,264
2,900
30,160
55,088
62,192
156,336
115,504
~
~
~
82,688
62,976
75,792
54,464
192,608
50,304
60,048
~
Storage cost
$105,213
~
$79,757
$1,907
$19,837
$36,232
$40,905
$102,825
$75,969
~
~
$54,385
$41,420
$49,850
$35,822
$126,681
$33,086
$39,494
~
Total cost per
project
$220,259
$18,156
$191,469
$45,055
$51,057
$140,427
$141,834
$248,307
$195,277
$42,908
$26,590
$77,520
$147,487
$115,701
$135,913
$141,422
$264,562
$130,834
$138,691
$99,480
Page 9-26
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
ATS cost
$71,043
$67,462
$123,112
$86,166
$27,634
$66,426
$8,959
$94,374
$110,251
$36,261
$86,589
$101,321
$37,739
$88,651
$76,983
$95,530
$97,629
$104,964
$106,628
$37,760
$108,171
$76,297
$34,152
$79,772
$94,665
$82,722
$100,462
$73,830
$34,569
$119,081
$97,923
Storage volume
over baseline
(cubic feet)
14,880
136,752
79,584
2,368
62,080
~
97,376
~
50,816
97,344
~
71,376
~
30,320
44,064
87,024
18,320
~
~
56,720
56,656
~
33,264
52,960
15,520
~
Storage cost
$9,787
$89,944
$52,344
$1,557
$40,831
~
$64,046
~
$33,422
$64,025
~
$46,945
~
$19,942
$28,982
$57,237
$12,049
~
~
$37,306
$37,264
~
$21,878
$34,833
$10,208
~
Total cost per
project
$80,830
$67,462
$213,056
$138,509
$29,192
$107,256
$8,959
$94,374
$174,297
$36,261
$120,011
$165,345
$37,739
$135,596
$76,983
$115,472
$126,611
$162,201
$106,628
$49,809
$108,171
$76,297
$34,152
$117,078
$131,929
$82,722
$122,341
$108,663
$44,776
$119,081
$97,923
Option 2 establishes a turbidity limit for construction sites larger than 30 acres that have an R-
factor > 50 and if the soils contain > 10 percent clay particles, by mass. To determine acres in-
scope for this option, EPA first determined the acres within each state that were located in areas
with an R-factor > 50 and with soils that contain > 10 percent clay particles. EPA calculated
these estimates by combining the soils data, R-factor data and RF1-level estimates of
development using GIS. Table 9-15 shows the state-level and national estimates of the percent of
each state's developed acres that fall into various combinations of R-factor and % clay content.
Based on the distribution of model projects by size (see Table 4-3), EPA determined the percent
of developed acres that would be in projects less than 30 acres (36.6 percent) and the acres that
would be in projects equal to or greater than 30 acres (63.4 percent). By multiplying the number
of acres in the R > 50 and > 10 percent clay content column in Table 9-15 by the quantity of
Page 9-27
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
developed acres for projects larger and smaller than 30 acres, EPA was able to determine the
quantity of developed acres in each state that would be subject to the Option 2 turbidity standard.
These results are shown in Table 9-16. The remainder of each state's developed acres in sites >
10 acres would be required to install larger sediment basins, if existing state requirements were
not equivalent.
To determine costs for Option 2, EPA divided acres in-scope for the turbidity limit into the three
large project categories (residential, nonresidential and transportation) according to the fraction
of acres in each category, on the basis of the NOT data. EPA then divided acres in each state by
the median project size of the three categories to determine the number of model projects
affected. Results were rounded to whole numbers to determine the number of model projects.
Table 9-16 presents the number of model projects in-scope for the turbidity requirement of
Option 2. Tables 9-17 and 9-18 present estimates of acres and model projects required to install
larger sediment basins under Option 2. By multiplying the number of model projects in each
state by the total cost for each project to implement ATS and provide storage for runoff from the
2-year, 24-hour storm, total ATS costs for Option 2 were estimated. For sites > 10 acres that are
not required to meet the turbidity limit, incremental costs to install 3,600 cf/acre sediment basins
were estimated if not already required by current state requirements.
Table 9-15. Developed Acres with R-Factor > 50 and Clay Content > 10%
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
% Acres with
only R < 50
0%
87%
0%
65%
77%
0%
0%
0%
0%
95%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
99%
% Acres
with only
< 10% clay
26%
0%
1%
2%
2%
57%
71%
99%
34%
0%
0%
10%
0%
8%
0%
19%
31%
16%
90%
68%
33%
9%
1%
0%
% Acres with
both R < 50 and
< 10% clay
0%
2%
0%
19%
3%
0%
0%
0%
0%
5%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
0%
1%
% Acres with
R > 50 and >
10% clay
74%
11%
99%
15%
18%
43%
29%
1%
66%
0%
100%
90%
100%
92%
100%
81%
69%
84%
10%
32%
67%
91%
99%
0%
Acres with
R > 50 and
> 10% clay
10,681
1,470
8,386
3,980
2,828
428
240
344
21,569
~
20,438
11,097
10,091
20,812
9,928
10,455
3,108
5,497
324
7,283
6,210
10,746
13,365
~
Page 9-28
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Nation
% Acres with
only R < 50
4%
94%
0%
0%
70%
0%
0%
31%
0%
0%
34%
0%
0%
0%
7%
0%
1%
94%
0%
0%
46%
0%
0%
96%
15%
% Acres
with only
< 10% clay
26%
0%
79%
55%
0%
23%
23%
1%
2%
6%
1%
1%
59%
66%
1%
1%
10%
0%
3%
12%
9%
1%
39%
0%
21%
% Acres with
both R < 50 and
< 10% clay
7%
6%
0%
0%
27%
0%
0%
1%
0%
0%
17%
0%
0%
0%
0%
0%
1%
6%
0%
0%
11%
0%
0%
4%
2%
% Acres with
R > 50 and >
10% clay
63%
0%
21%
45%
2%
77%
77%
68%
98%
94%
47%
99%
41%
34%
92%
99%
88%
0%
97%
88%
34%
99%
61%
0%
63%
Acres with
R > 50 and
> 10% clay
3,817
~
375
1,938
111
5,960
14,514
4,467
17,135
15,722
3,454
15,920
154
5,456
7,631
13,001
53,785
~
551
13,368
4,410
3,474
4,600
~
368,763
9.4.7. SUMMARY OF OPTION COSTS
The following tables present the compliance costs estimates for each of the regulatory options.
For Option 2, the costs per model project vary by whether a specific project is required to meet
the turbidity requirement. Note that for all options, no incremental costs are assumed for sites
smaller than 10 acres. Table 9-19 presents the costs for Option 1. Table 9-20 presents the costs
for the segment of the industry required to meet the turbidity standard, Table 9-21 presents the
costs for the segment of the industry required to install only larger sediment basins, and Table 9-
22 presents the total costs for Option 2. Table 9-23 presents the costs for Option 3. All costs are
presented in year 2008 dollars.
Page 9-29
-------
Table 9-16. Acres and Model Projects In-Scope for Turbidity Limit of Option 2
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
Acres
Large
residential
Large
nonresidential
Large
transportation
Total
acres
Model projects
Large
residential
Large
nonresidential
Large
transportation
Total
projects
Not Analyzed
~
462
2,541
1,221
858
132
66
99
6,567
~
357
2,142
1,020
714
102
51
102
5,508
~
79
631
316
237
~
~
~
1,578
~
898
5,314
2,557
1,809
234
117
201
13,653
~
14
77
37
26
4
2
3
199
~
7
42
20
14
2
1
2
108
~
1
8
4
3
~
~
~
20
~
22
127
61
43
6
3
5
327
Not Analyzed
~
6,204
3,366
3,069
6,336
3,036
3,168
957
1,683
99
2,211
1,881
3,267
4,059
~
1,155
~
99
~
5,202
2,805
2,550
5,304
2,550
2,652
816
1,377
102
1,836
1,581
2,754
3,417
~
969
~
102
~
1,499
868
789
1,578
710
789
237
395
~
552
473
789
1,026
~
316
~
~
~
12,905
7,039
6,408
13,218
6,296
6,609
2,010
3,455
201
4,599
3,935
6,810
8,502
~
2,440
~
201
~
188
102
93
192
92
96
29
51
3
67
57
99
123
35
~
3
~
102
55
50
104
50
52
16
27
2
36
31
54
67
~
19
~
2
~
19
11
10
20
9
10
3
5
~
7
6
10
13
~
4
~
~
~
309
168
153
316
151
158
48
83
5
110
94
163
203
~
58
~
5
i
-------
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
Nation
Acres
Large
residential
594
33
1,815
4,422
1,353
5,214
4,785
1,056
4,851
33
1,650
2,310
3,960
16,368
~
165
4,059
1,353
1,056
1,386
~
Large
nonresidential
510
51
1,530
3,723
1,122
4,386
4,029
867
4,080
51
1,377
1,938
3,315
13,719
~
153
3,417
1,122
867
1,173
~
Large
transportation
158
~
473
1,105
316
1,262
1,184
237
1,184
~
395
552
947
4,024
~
79
1,026
316
237
316
~
Total
acres
1,262
84
3,818
9,250
2,791
10,862
9,998
2,160
10,115
84
3,422
4,800
8,222
34,111
~
397
8,502
2,791
2,160
2,875
~
Model projects
Large
residential
18
1
55
134
41
158
145
32
147
1
50
70
120
496
~
5
123
41
32
42
~
Large
nonresidential
10
1
30
73
22
86
79
17
80
1
27
38
65
269
~
3
67
22
17
23
~
Large
transportation
2
~
6
14
4
16
15
3
15
~
5
7
12
51
~
1
13
4
3
4
~
Total
projects
30
2
91
221
67
260
239
52
242
2
82
115
197
816
~
9
203
67
52
69
~
Not Analyzed
Not Analyzed
112,233
94,146
27,457
233,836
3,401
1,846
348
5,595
era
re
-------
Table 9-17. Acres Required to Install Larger Sediment Basins Under Option 2
era
re
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
Large
residential
Medium
residential
Large
nonresidential
Medium
nonresidential
Large
transportation
Medium
transportation
Total
acres
Not Analyzed
1,188
~
~
~
3,960
~
~
~
3,333
1,837
~
~
~
2,004
~
~
~
4,125
1,020
~
~
~
3,315
~
~
~
2,805
1,335
~
~
~
1,455
~
~
~
3,000
316
~
~
~
947
~
~
~
868
176
~
~
~
192
~
~
~
384
5,872
~
~
~
11,873
~
~
~
14,515
Not Analyzed
~
~
396
~
~
~
~
~
~
~
~
~
~
~
1,947
693
~
~
693
~
~
1,570
~
~
~
~
~
~
~
~
~
~
~
818
768
~
~
534
~
~
357
~
~
~
~
~
~
~
~
~
~
~
1,632
561
~
~
561
~
~
1,140
~
~
~
~
~
~
~
~
~
~
~
600
555
~
~
390
~
~
79
~
~
~
~
~
~
~
~
~
~
~
473
158
~
~
158
~
~
144
~
~
~
~
~
~
~
~
~
~
~
80
64
~
~
48
~
~
3,686
~
~
~
~
~
~
~
~
~
~
~
5,551
2,799
~
~
2,384
-------
era
re
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
Totals
Large
residential
~
~
1,287
66
~
~
~
66
~
~
~
~
~
~
~
~
924
858
Medium
residential
~
~
2,371
2,204
~
~
~
50
~
~
~
~
~
67
~
~
~
952
351
Large
nonresidential
~
~
1,071
~
51
~
~
~
51
~
~
~
~
~
~
~
~
~
765
714
Medium
nonresidential
~
~
1,725
~
1,605
~
~
~
30
~
~
~
~
~
45
~
~
~
690
255
Large
transportation
~
~
316
~
79
~
~
~
-
~
~
~
~
~
~
~
~
237
237
Medium
transportation
~
~
224
~
208
~
~
~
-
~
~
~
~
~
~
~
~
~
96
32
Total
acres
~
~
6,994
~
4,213
~
~
~
197
~
~
~
~
~
112
~
~
~
3,664
2,446
Not Analyzed
Not Analyzed
15,411
17,652
12,903
12,825
3,866
1,648
64,305
-------
Table 9-18. Model Projects Required to Install Larger Sediment Basins Under Option 2
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
Large
residential
Medium
residential
Large
nonresidential
Medium
nonresidential
Large
transportation
Medium
transportation
Total
projects
Not Analyzed
36
~
~
120
~
~
~
101
110
~
~
~
120
~
~
~
247
20
~
~
65
~
~
~
55
89
~
~
97
~
~
~
200
4
~
~
12
~
~
~
11
11
~
~
12
~
~
~
24
270
-
-
-
426
~
~
~
638
Not Analyzed
~
~
12
~
~
~
~
~
~
~
~
~
~
59
21
~
~
21
~
~
94
~
~
~
~
~
~
~
~
~
~
~
49
46
~
~
32
~
~
7
~
~
~
~
~
~
~
~
~
~
32
11
~
~
11
~
~
76
~
~
~
~
~
~
~
~
~
~
40
37
~
~
26
~
~
1
~
~
~
~
~
~
~
~
~
~
6
2
~
~
2
~
~
9
~
~
~
~
~
~
~
~
~
~
5
4
~
~
3
~
~
199
~
~
~
~
~
~
~
~
~
~
~
191
121
~
~
95
i
-------
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
Totals
Large
residential
~
~
39
~
2
~
~
~
2
~
~
~
~
~
~
~
~
28
26
Medium
residential
~
~
142
132
~
~
~
3
~
~
~
~
~
4
~
~
~
57
21
Large
nonresidential
~
~
21
1
~
~
~
1
~
~
~
~
~
-
~
~
~
15
14
Medium
nonresidential
~
~
115
107
~
~
~
2
~
~
~
~
~
3
~
~
~
46
17
Large
transportation
~
~
4
1
~
~
~
~
~
~
~
~
~
-
~
~
~
3
3
Medium
transportation
~
~
14
13
~
~
~
~
~
~
~
~
~
-
~
~
~
6
2
Total
projects
~
~
335
~
256
~
~
~
8
~
~
~
~
~
7
~
~
~
155
83
Not Analyzed
Not Analyzed
467
1,057
253
855
49
103
2,784
era
re
in
-------
Table 9-19a. Option 1 Costs by Model Project Type and State ($2008); Transportation
as
era
re
o\
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Medium transportation
#
Projects
Cost per
project ($)
Total cost
($)
Large transportation
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
TRANSPORTATION
#
Projects
Total costs ($)
Not Analyzed
11
0
0
0
12
0
0
0
24
$18,942
~
~
~
$18,942
~
~
~
$18,942
$208,364
~
~
~
$227,306
~
~
~
$454,613
14
0
0
0
15
0
0
0
31
$93,409
~
~
~
$93,409
~
~
~
$93,409
$1,307,722
~
~
~
$1,401,130
~
~
~
$2,895,669
25
0
0
0
27
0
0
0
55
$1,516,086
~
~
~
$1,628,437
~
~
~
$3,350,282
Not Analyzed
0
0
9
0
0
0
0
0
0
0
0
0
0
0
~
~
$18,942
~
~
~
~
~
~
~
~
~
~
~
~
~
$170,480
~
~
~
~
~
~
~
~
~
~
~
0
0
12
0
0
0
0
0
0
0
0
0
0
0
~
~
$93,409
~
~
~
~
~
~
~
~
~
~
~
~
~
$1,120,904
~
~
~
~
~
~
~
~
~
~
~
0
0
21
0
0
0
0
0
0
0
0
0
0
0
~
~
$1,291,384
~
~
~
~
~
~
~
~
~
~
~
-------
as
era
re
State
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Transportation
Medium transportation
#
Projects
5
4
0
0
3
0
0
14
0
13
0
0
0
0
0
0
0
0
0
0
0
0
0
6
2
0
103
Cost per
project ($)
$1,557
$18,942
~
~
$18,942
~
~
$18,942
~
$18,942
~
~
~
~
~
~
~
~
~
~
~
~
~
$10,797
$10,208
~
Total cost
($)
$7,787
$75,769
~
~
$56,827
~
~
$265,191
~
$246,249
~
~
~
~
~
~
~
~
~
~
~
~
~
$64,782
$20,415
~
$1,797,783
Large transportation
#
Projects
6
6
0
0
4
0
0
18
0
17
0
0
0
0
0
0
0
0
0
1
0
0
0
7
3
0
134
Cost per
project ($)
$7,680
$93,409
~
~
$93,409
~
~
$93,409
~
$93,409
~
~
~
~
~
~
~
~
~
$93,409
~
~
~
$53,243
$50,337
~
Total cost ($)
$46,082
$560,452
~
~
$373,635
~
~
$1,681,356
~
$1,587,948
~
~
~
~
~
~
~
~
~
$93,409
~
~
~
$372,701
$151,011
~
$11,592,019
TOTALS
TRANSPORTATION
#
Projects
11
10
0
0
7
0
0
32
0
30
0
0
0
0
0
0
0
0
0
1
0
0
0
13
5
0
237
Total costs ($)
$53,869
$636,221
~
~
$430,461
~
~
$1,946,547
~
$1,834,196
~
~
~
~
~
~
~
~
~
$93,409
~
~
~
$437,483
$171,426
~
$13,389,801
-------
Table 9-19b. Option 1 Costs by Model Project Type and State ($2008); Residential
as
era
re
00
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Medium residential
#
Projects
Cost per
project ($)
Total cost
($)
Large residential
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
RESIDENTIAL
#
Projects
Total costs ($)
Not Analyzed
110
0
0
0
120
0
0
0
247
$19,771
~
~
~
$19,771
~
~
~
$19,771
$2,174,801
~
~
~
$2,372,510
~
~
~
$4,883,416
134
0
0
0
146
0
0
0
300
$39,068
~
~
~
$39,068
~
~
~
$39,068
$5,235,149
~
~
~
$5,703,968
~
~
~
$11,720,482
244
0
0
0
266
0
0
0
547
$7,409,949
~
~
~
$8,076,478
~
~
~
$16,603,898
Not Analyzed
0
0
94
0
0
0
0
0
0
0
0
0
0
0
49
~
~
$19,771
~
~
~
~
~
~
~
~
~
~
~
$1,626
~
~
$1,858,466
~
~
~
~
~
~
~
~
~
~
~
$79,655
0
0
114
0
0
0
0
0
0
0
0
0
0
0
59
~
~
$39,068
~
~
~
~
~
~
~
~
~
~
~
$3,212
~
~
$4,453,783
~
~
~
~
~
~
~
~
~
~
~
$189,525
0
0
208
0
0
0
0
0
0
0
0
0
0
0
108
~
~
$6,312,249
~
~
~
~
~
~
~
~
~
~
~
$269,179
-------
as
era
re
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Residential
Medium residential
#
Projects
46
0
0
32
0
0
142
0
132
0
0
0
3
0
0
0
0
0
4
0
0
0
57
21
0
1,057
Cost per
project ($)
$19,771
~
~
$19,771
~
~
$19,771
~
$19,771
~
~
~
$19,771
~
~
~
~
~
$19,771
~
~
~
$11,269
$10,654
~
Total cost
($)
$909,462
~
~
$632,669
~
~
$2,807,470
~
$2,609,761
~
~
~
$59,313
~
~
~
~
~
$79,084
~
~
~
$642,357
$223,741
~
$19,332,703
Large residential
#
Projects
56
0
0
39
0
0
173
0
160
0
0
0
3
0
0
0
0
0
5
0
0
0
70
26
0
1,285
Cost per
project ($)
$39,068
~
~
$39,068
~
~
$39,068
~
$39,068
~
~
~
$39,068
~
~
~
~
~
$39,068
~
~
~
$22,269
$21,053
~
Total cost ($)
$2,187,823
~
~
$1,523,663
~
~
$6,758,811
~
$6,250,924
~
~
~
$117,205
~
~
~
~
~
$195,341
~
~
~
$1,558,824
$547,390
~
$46,442,889
TOTALS
RESIDENTIAL
#
Projects
102
0
0
71
0
0
315
0
292
0
0
0
6
0
0
0
0
0
9
0
0
0
127
47
0
2,342
Total costs ($)
$3,097,285
~
~
$2,156,332
~
~
$9,566,281
~
$8,860,685
~
~
~
$176,518
~
~
~
~
~
$274,425
~
~
~
$2,201,181
$771,131
~
$65,775,592
-------
Table 9-19c. Option 1 Costs by Model Project Type and State ($2008); Nonresidential
as
era
re
4-
O
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Medium nonresidential
#
Projects
Cost per
Project ($)
Total cost
($)
Large nonresidential
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
NONRESIDENTIAL
#
Projects
Total costs ($)
Not Analyzed
89
0
0
0
97
0
0
0
200
$17,758
~
~
~
$17,758
~
~
~
$17,758
$1,580,489
~
~
~
$1,722,556
~
~
~
$3,551,661
73
0
0
0
79
0
0
0
163
$60,378
~
~
~
$60,378
~
~
~
$60,378
$4,407,612
~
~
~
$4,769,881
~
~
~
$9,841,654
162
0
0
0
176
0
0
0
363
$5,988,101
~
~
~
$6,492,437
~
~
~
$13,393,315
Not Analyzed
0
0
76
0
0
0
0
0
0
0
0
0
0
0
40
~
~
$17,758
~
~
~
~
~
~
~
~
~
~
~
$1,460
~
~
$1,349,631
~
~
~
~
~
~
~
~
~
~
~
$58,405
0
0
62
0
0
0
0
0
0
0
0
0
0
0
32
~
~
$60,378
~
~
~
~
~
~
~
~
~
~
~
$4,964
~
~
$3,743,451
~
~
~
~
~
~
~
~
~
~
~
$158,862
0
0
138
0
0
0
0
0
0
0
0
0
0
0
72
~
~
$5,093,082
~
~
~
~
~
~
~
~
~
~
~
$217,267
-------
as
era
re
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Nonresidential
Medium nonresidential
#
Projects
37
0
0
26
0
0
115
0
107
0
0
0
2
0
0
0
0
0
3
0
0
0
46
17
0
855
Cost per
Project ($)
$17,758
~
~
$17,758
~
~
$17,758
~
$17,758
~
~
~
$17,758
~
~
~
~
~
$17,758
~
~
~
$10,122
$9,570
~
Total cost
($)
$657,057
~
~
$461,716
~
~
$2,042,205
~
$1,900,139
~
~
~
$35,517
~
~
~
~
~
$53,275
~
~
~
$465,623
$162,686
~
$14,040,960
Large nonresidential
#
Projects
30
0
0
21
0
0
94
0
87
0
0
0
2
0
0
0
0
0
3
0
0
0
38
14
0
698
Cost per
project ($)
$60,378
~
~
$60,378
~
~
$60,378
~
$60,378
~
~
~
$60,378
~
~
~
~
~
$60,378
~
~
~
$34,416
$32,537
~
Total cost ($)
$1,811,347
~
~
$1,267,943
~
~
$5,675,555
~
$5,252,907
~
~
~
$120,756
~
~
~
~
~
$181,135
~
~
~
$1,307,793
$455,520
~
$38,994,416
TOTALS
NONRESIDENTIAL
#
Projects
67
0
0
47
0
0
209
0
194
0
0
0
4
0
0
0
0
0
6
0
0
0
84
31
0
1,554
Total costs ($)
$2,468,405
~
~
$1,729,659
~
~
$7,717,760
~
$7,153,046
~
~
~
$156,273
~
~
~
~
~
$234,410
~
~
~
$1,773,416
$618,206
~
$53,035,376
-------
Table 9-20. Option 2 Costs for Sites Required to Meet Turbidity Standard ($2008)
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New
Transportation
#
Projects
10
1
8
4
3
0
0
0
20
0
0
19
11
10
20
9
10
3
5
0
7
6
10
13
0
4
0
0
Cost per
project ($)
$1,086,150
$89,531
$944,183
$222,176
$251,774
$692,483
$699,421
$1,224,462
$962,958
$211,589
$131,124
$382,270
$727,296
$570,549
$670,223
$697,387
$1,304,620
$645,174
$683,922
$490,559
$398,591
$332,670
$1,050,633
$683,023
$143,951
$528,909
$44,178
$465,382
Total cost ($)
$10,861,500
$89,531
$7,553,461
$888,705
$755,321
~
~
$19,259,168
~
$7,263,130
$8,000,261
$5,705,488
$13,404,452
$6,276,480
$13,046,203
$1,935,523
$3,419,608
~
$2,790,135
$1,996,017
$10,506,327
$8,879,300
$2,115,634
-
Large residential
#
Projects
98
14
77
37
26
4
2
3
199
0
0
188
102
93
192
92
96
29
51
3
67
57
99
123
0
35
0
3
Cost per
project ($)
$454,283
$37,447
$394,905
$92,925
$105,305
$289,632
$292,533
$512,133
$402,758
$88,497
$54,843
$159,885
$304,192
$238,633
$280,321
$291,683
$545,659
$269,845
$286,051
$205,177
$166,711
$139,139
$439,428
$285,675
$60,207
$221,217
$18,477
$194,647
Total cost ($)
$44,519,762
$524,252
$30,407,705
$3,438,242
$2,737,918
$1,158,526
$585,067
$1,536,398
$80,148,893
~
$30,058,340
$31,027,629
$22,192,831
$53,821,677
$26,834,802
$52,383,233
$7,825,500
$14,588,593
$615,530
$11,169,632
$7,930,944
$43,503,385
$35,138,029
$7,742,578
$583,940
Large nonresidential
#
Projects
53
7
42
20
14
2
1
2
108
0
0
102
55
50
104
50
52
16
27
2
36
31
54
67
0
19
0
2
Cost per
project ($)
$702,074
$57,872
$610,308
$143,612
$162,743
$447,612
$452,097
$791,478
$622,445
$136,768
$84,757
$247,095
$470,116
$368,796
$433,224
$450,782
$843,291
$417,033
$442,079
$317,091
$257,644
$215,034
$679,116
$441,498
$93,048
$341,880
$28,556
$300,817
Total cost ($)
$37,209,931
$405,104
$25,632,942
$2,872,241
$2,278,407
$895,225
$452,097
$1,582,955
$67,224,015
~
$25,203,656
$25,856,358
$18,439,791
$45,055,267
$22,539,112
$43,851,115
$6,672,527
$11,936,121
$634,182
$9,275,190
$6,666,040
$36,672,275
$29,580,351
$6,495,722
$601,635
TOTALS
#
Projects
161
22
127
61
43
6
3
5
327
0
0
309
168
153
316
151
158
48
83
5
110
94
163
203
0
58
0
5
Total costs ($)
$92,591,194
$1,018,887
$63,594,107
$7,199,188
$5,771,645
$2,053,751
$1,037,164
$3,119,353
$166,632,076
~
$62,525,126
$64,884,248
$46,338,110
$112,281,395
$55,650,394
$109,280,551
$16,433,550
$29,944,322
$1,249,713
$23,234,957
$16,593,001
$90,681,988
$73,597,680
$16,353,934
$1,185,575
-------
State
Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
National
Totals
Transportation
#
Projects
2
0
6
14
4
16
15
3
15
0
5
7
12
51
0
1
13
4
3
4
0
0
0
348
Cost per
project ($)
$859,500
$178,812
$591,806
$815,359
$186,098
$668,658
$379,622
$569,422
$624,350
$799,855
$525,810
$245,621
$533,418
$376,238
$168,410
$577,339
$650,573
$407,925
$603,292
$535,844
$220,803
$587,220
$482,882
Total cost ($)
$1,719,000
~
$3,550,834
$11,415,025
$744,392
$10,698,529
$5,694,323
$1,708,267
$9,365,254
~
$2,629,051
$1,719,346
$6,401,013
$19,188,136
~
$577,339
$8,457,453
$1,631,698
$1,809,877
$2,143,375
~
~
$214,199,156
Large residential
#
Projects
18
1
55
134
41
158
145
32
147
1
50
70
120
496
0
5
123
41
32
42
0
0
0
3,401
Cost per
project ($)
$359,487
$74,788
$247,523
$341,025
$77,836
$279,667
$158,777
$238,161
$261,135
$334,540
$219,921
$102,731
$223,102
$157,362
$70,438
$241,473
$272,103
$170,615
$252,328
$224,117
$92,351
$245,605
$201,966
Total cost ($)
$6,470,760
$74,788
$13,613,779
$45,697,303
$3,191,263
$44,187,367
$23,022,673
$7,621,165
$38,386,861
$334,540
$10,996,029
$7,191,179
$26,772,296
$78,051,495
~
$1,207,363
$33,468,658
$6,995,208
$8,074,483
$9,412,922
~
~
$875,243,539
Large nonresidential
#
Projects
10
1
30
73
22
86
79
17
80
1
27
38
65
269
0
3
67
22
17
23
0
0
0
1,846
Cost per
project ($)
$555,570
$115,582
$382,536
$527,038
$120,292
$432,212
$245,383
$368,068
$403,572
$517,016
$339,877
$158,766
$344,795
$243,196
$108,858
$373,185
$420,523
$263,677
$389,961
$346,363
$142,724
$379,572
$312,129
Total cost ($)
$5,555,703
$115,582
$11,476,078
$38,473,781
$2,646,414
$37,170,271
$19,385,235
$6,257,150
$32,285,795
$517,016
$9,176,686
$6,033,119
$22,411,657
$65,419,627
~
$1,119,555
$28,175,020
$5,800,904
$6,629,334
$7,966,347
~
~
$734,647,534
TOTALS
#
Projects
30
2
91
221
67
260
239
52
242
2
82
115
197
816
0
9
203
67
52
69
0
0
0
5,595
Total costs ($)
$13,745,464
$190,370
$28,640,690
$95,586,109
$6,582,069
$92,056,167
$48,102,231
$15,586,582
$80,037,910
$851,556
$22,801,766
$14,943,644
$55,584,966
$162,659,258
~
$2,904,257
$70,101,131
$14,427,810
$16,513,694
$19,522,645
~
~
$1,824,090,229
-------
Table 9-21a. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008); Transportation
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Medium transportation
# Projects
Cost per
project ($)
Total cost
($)
Large transportation
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
TRANSPORTATION
# Projects
Total costs ($)
Not Analyzed
11
0
0
0
12
0
0
0
24
$18,942
~
~
~
$18,942
~
~
~
$18,942
$208,364
~
~
~
$227,306
~
~
~
$454,613
4
0
0
0
12
0
0
0
11
$93,409
~
~
~
$93,409
~
~
~
$93,409
$373,635
~
~
~
$1,120,904
~
~
~
$1,027,496
15
0
0
0
24
0
0
0
35
$581,999
~
~
~
$1,348,211
~
~
~
$1,482,108
Not Analyzed
0
0
9
0
0
0
0
0
0
0
0
0
0
0
~
~
$18,942
~
~
~
~
~
~
~
~
~
~
~
~
~
$170,480
~
~
~
~
~
~
~
~
~
~
~
0
0
1
0
0
0
0
0
0
0
0
0
0
0
~
~
$93,409
~
~
~
~
~
~
~
~
~
~
~
~
~
$93,409
~
~
~
~
~
~
~
~
~
~
~
0
0
10
0
0
0
0
0
0
0
0
0
0
0
~
~
$263,888
~
~
~
~
~
~
~
~
~
~
~
o
s
-------
State
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Transportation
Medium transportation
# Projects
5
4
0
0
3
0
0
14
0
13
0
0
0
0
0
0
0
0
0
0
0
0
0
6
2
0
103
Cost per
project ($)
$1,557
$18,942
~
~
$18,942
~
~
$18,942
~
$18,942
~
~
~
~
~
~
~
~
~
~
~
~
~
$10,797
$10,208
~
Total cost
($)
$7,787
$75,769
~
~
$56,827
~
~
$265,191
~
$246,249
~
~
~
~
~
~
~
~
~
~
~
~
~
$64,782
$20,415
~
$1,797,783
Large transportation
#
Projects
6
2
0
0
2
0
0
4
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
3
3
0
49
Cost per
project ($)
$7,680
$93,409
~
~
$93,409
~
~
$93,409
~
$93,409
~
~
~
~
~
~
~
~
~
~
~
~
~
$53,243
$50,337
~
Total cost ($)
$46,082
$186,817
~
~
$186,817
~
~
$373,635
~
$93,409
~
~
~
~
~
~
~
~
~
~
~
~
~
$159,729
$151,011
~
$3,812,943
TOTALS
TRANSPORTATION
# Projects
11
6
0
0
5
0
0
18
0
14
0
0
0
0
0
0
0
0
0
0
0
0
0
9
5
0
152
Total costs ($)
$53,869
$262,586
~
~
$243,644
~
~
$638,825
~
$339,657
~
~
~
~
~
~
~
~
~
~
~
~
~
$224,511
$171,426
~
$5,610,725
o
s
-------
Table 9-21b. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008); Residential
as
era
re
4-
O\
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Medium residential
#
Projects
Cost per
project ($)
Total cost
($)
Large residential
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
RESIDENTIAL
#
Projects
Total costs ($)
Not Analyzed
110
0
0
0
120
0
0
0
247
$19,771
~
~
~
$19,771
~
~
~
$19,771
$2,174,801
~
~
~
$2,372,510
~
~
~
$4,883,416
36
0
0
0
120
0
0
0
101
$39,068
~
~
~
$39,068
~
~
~
$39,068
$1,406,458
~
~
~
$4,688,193
~
~
~
$3,945,896
146
0
0
0
240
0
0
0
348
$3,581,258
~
~
~
$7,060,703
~
~
~
$8,829,312
Not Analyzed
0
0
94
0
0
0
0
0
0
0
0
0
0
0
49
~
~
$19,771
~
~
~
~
~
~
~
~
~
~
~
$1,626
~
~
$1,858,466
~
~
~
~
~
~
~
~
~
~
~
$79,655
0
0
12
0
0
0
0
0
0
0
0
0
0
0
59
~
~
$39,068
~
~
~
~
~
~
~
~
~
~
~
$3,212
~
~
$468,819
~
~
~
~
~
~
~
~
~
~
~
$189,525
0
0
106
0
0
0
0
0
0
0
0
0
0
0
108
~
~
$2,327,285
~
~
~
~
~
~
~
~
~
~
~
$269,179
-------
as
era
re
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Residential
Medium residential
#
Projects
46
0
0
32
0
0
142
0
132
0
0
0
3
0
0
0
0
0
4
0
0
0
57
21
0
1,057
Cost per
project ($)
$19,771
~
~
$19,771
~
~
$19,771
~
$19,771
~
~
~
$19,771
~
~
~
~
~
$19,771
~
~
~
$11,269
$10,654
~
Total cost
($)
$909,462
~
~
$632,669
~
~
$2,807,470
~
$2,609,761
~
~
~
$59,313
~
~
~
~
~
$79,084
~
~
~
$642,357
$223,741
~
$19,332,703
Large residential
#
Projects
21
0
0
21
0
0
39
0
2
0
0
0
2
0
0
0
0
0
0
0
0
0
28
26
0
467
Cost per
project ($)
$39,068
~
~
$39,068
~
~
$39,068
~
$39,068
~
~
~
$39,068
~
~
~
~
~
~
~
~
~
$22,269
$21,053
~
Total cost ($)
$820,434
~
~
$820,434
~
~
$1,523,663
~
$78,137
~
~
~
$78,137
~
~
~
~
~
~
~
~
~
$623,530
$547,390
~
$15,190,613
TOTALS
RESIDENTIAL
#
Projects
67
0
0
53
0
0
181
0
134
0
0
0
5
0
0
0
0
0
4
0
0
0
85
47
0
1,524
Total costs ($)
$1,729,896
~
~
$1,453,103
~
~
$4,331,133
~
$2,687,897
~
~
~
$137,449
~
~
~
~
~
$79,084
~
~
~
$1,265,887
$771,131
~
$34,523,317
-------
Table 9-21c. Option 2 Costs for Projects Installing Larger Sediment Basins ($2008); Nonresidential
as
era
re
4-
00
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Medium nonresidential
#
Projects
Cost per
project ($)
Total cost
($)
Large nonresidential
#
Projects
Cost per
project ($)
Total cost ($)
TOTALS
NONRESIDENTIAL
#
Projects
Total costs ($)
Not Analyzed
89
0
0
0
97
0
0
0
200
$17,758
~
~
~
$17,758
~
~
~
$17,758
$1,580,489
~
~
~
$1,722,556
~
~
~
$3,551,661
20
0
0
0
65
0
0
0
55
$60,378
~
~
~
$60,378
~
~
~
$60,378
$1,207,565
~
~
~
$3,924,586
~
~
~
$3,320,803
109
0
0
0
162
0
0
0
255
$2,788,054
~
~
~
$5,647,142
~
~
~
$6,872,465
Not Analyzed
0
0
76
0
0
0
0
0
0
0
0
0
0
0
40
~
~
$17,758
~
~
~
~
~
~
~
~
~
~
~
$1,460
~
~
$1,349,631
~
~
~
~
~
~
~
~
~
~
~
$58,405
0
0
7
0
0
0
0
0
0
0
0
0
0
0
32
~
~
$60,378
~
~
~
~
~
~
~
~
~
~
~
$4,964
~
~
$422,648
~
~
~
~
~
~
~
~
~
~
~
$158,862
0
0
83
0
0
0
0
0
0
0
0
0
0
0
72
~
~
$1,772,279
~
~
~
~
~
~
~
~
~
~
~
$217,267
-------
as
era
re
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
Total Nonresidential
Medium nonresidential
#
Projects
37
0
0
26
0
0
115
0
107
0
0
0
2
0
0
0
0
0
3
0
0
0
46
17
0
855
Cost per
project ($)
$17,758
~
~
$17,758
~
~
$17,758
~
$17,758
~
~
~
$17,758
~
~
~
~
~
$17,758
~
~
~
$10,122
$9,570
~
Total cost
($)
$657,057
~
~
$461,716
~
~
$2,042,205
~
$1,900,139
~
~
~
$35,517
~
~
~
~
~
$53,275
~
~
~
$465,623
$162,686
~
$14,040,960
Large nonresidential
#
Projects
11
0
0
11
0
0
21
0
1
0
0
0
1
0
0
0
0
0
0
0
0
0
15
14
0
253
Cost per
project ($)
$60,378
~
~
$60,378
~
~
$60,378
~
$60,378
~
~
~
$60,378
~
~
~
~
~
~
~
~
~
$34,416
$32,537
~
Total cost ($)
$664,161
~
~
$664,161
~
~
$1,267,943
~
$60,378
~
~
~
$60,378
~
~
~
~
~
~
~
~
~
$516,234
$455,520
~
$12,723,239
TOTALS
NONRESIDENTIAL
#
Projects
48
0
0
37
0
0
136
0
108
0
0
0
3
0
0
0
0
0
3
0
0
0
61
31
0
1,108
Total costs ($)
$1,321,218
~
~
$1,125,877
~
~
$3,310,148
~
$1,960,517
~
~
~
$95,895
~
~
~
~
~
$53,275
~
~
~
$981,857
$618,206
~
$26,764,199
-------
Table 9-22. Option 2 Total Costs ($2008)
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Transportation
#
Projects
Total cost ($)
Residential
#
Projects
Total cost ($)
Nonresidential
#
Projects
Total cost ($)
TOTALS
#
Projects
Total costs ($)
Not Analyzed
25
1
8
4
27
0
0
0
55
$11,443,499
$89,531
$7,553,461
$888,705
$2,103,531
~
~
~
$20,741,276
244
14
77
37
266
4
2
3
547
$48,101,021
$524,252
$30,407,705
$3,438,242
$9,798,620
$1,158,526
$585,067
$1,536,398
$88,978,205
162
7
42
20
176
2
1
2
363
$39,997,985
$405,104
$25,632,942
$2,872,241
$7,925,548
$895,225
$452,097
$1,582,955
$74,096,479
431
22
127
61
469
6
3
5
965
$99,542,505
$1,018,887
$63,594,107
$7,199,188
$19,827,700
$2,053,751
$1,037,164
$3,119,353
$183,815,960
Not Analyzed
0
19
21
10
20
9
10
3
5
0
7
6
10
13
11
~
$7,263,130
$8,264,150
$5,705,488
$13,404,452
$6,276,480
$13,046,203
$1,935,523
$3,419,608
~
$2,790,135
$1,996,017
$10,506,327
$8,879,300
$53,869
0
188
208
93
192
92
96
29
51
3
67
57
99
123
108
~
$30,058,340
$33,354,914
$22,192,831
$53,821,677
$26,834,802
$52,383,233
$7,825,500
$14,588,593
$615,530
$11,169,632
$7,930,944
$43,503,385
$35,138,029
$269,179
0
102
138
50
104
50
52
16
27
2
36
31
54
67
72
~
$25,203,656
$27,628,637
$18,439,791
$45,055,267
$22,539,112
$43,851,115
$6,672,527
$11,936,121
$634,182
$9,275,190
$6,666,040
$36,672,275
$29,580,351
$217,267
0
309
367
153
316
151
158
48
83
5
110
94
163
203
191
~
$62,525,126
$69,247,701
$46,338,110
$112,281,395
$55,650,394
$109,280,551
$16,433,550
$29,944,322
$1,249,713
$23,234,957
$16,593,001
$90,681,988
$73,597,680
$540,315
-------
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Totals
Transportation
#
Projects
10
0
0
7
0
6
32
4
30
15
3
15
0
5
7
12
51
0
1
13
4
3
13
5
0
500
Total cost ($)
$2,378,221
~
~
$1,962,644
~
$3,550,834
$12,053,851
$744,392
$11,038,187
$5,694,323
$1,708,267
$9,365,254
~
$2,629,051
$1,719,346
$6,401,013
$19,188,136
~
$577,339
$8,457,453
$1,631,698
$1,809,877
$2,367,887
$171,426
~
219,809,881
Residential
#
Projects
102
0
3
71
1
55
315
41
292
145
32
147
6
50
70
120
496
0
9
123
41
32
127
47
0
4,925
Total cost ($)
$9,472,474
~
$583,940
$7,923,863
$74,788
$13,613,779
$50,028,436
$3,191,263
$46,875,264
$23,022,673
$7,621,165
$38,386,861
$471,989
$10,996,029
$7,191,179
$26,772,296
$78,051,495
~
$1,286,447
$33,468,658
$6,995,208
$8,074,483
$10,678,809
$771,131
~
$909,766,855
Nonresidential
#
Projects
67
0
2
47
1
30
209
22
194
79
17
80
4
27
38
65
269
0
6
67
22
17
84
31
0
2,954
Total cost ($)
$7,816,940
~
$601,635
$6,681,580
$115,582
$11,476,078
$41,783,929
$2,646,414
$39,130,788
$19,385,235
$6,257,150
$32,285,795
$612,911
$9,176,686
$6,033,119
$22,411,657
$65,419,627
~
$1,172,830
$28,175,020
$5,800,904
$6,629,334
$8,948,204
$618,206
~
$761,411,733
TOTALS
#
Projects
179
0
5
125
2
91
556
67
516
239
52
242
10
82
115
197
816
0
16
203
67
52
224
83
0
8,379
Total costs ($)
$19,667,634
~
$1,185,575
$16,568,087
$190,370
$28,640,690
$103,866,215
$6,582,069
$97,044,238
$48,102,231
$15,586,582
$80,037,910
$1,084,900
$22,801,766
$14,943,644
$55,584,966
$162,659,258
~
$3,036,615
$70,101,131
$14,427,810
$16,513,694
$21,994,900
$1,560,763
~
$1,890,988,470
-------
Table 9-23. Option 3 Total Costs ($2008)
State
Alaska
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Transportation
#
Projects
Total cost ($)
Residential
#
Projects
Total cost ($)
Nonresidential
#
Projects
Total cost ($)
TOTALS
#
Projects
Total costs ($)
Not Analyzed
25
23
14
46
27
2
2
64
55
$17,628,945
$1,345,467
$8,702,276
$6,677,679
$4,389,284
$832,910
$841,255
$51,033,234
$34,538,351
244
229
142
461
266
17
14
639
547
$86,162,397
$6,670,144
$43,592,754
$33,291,528
$21,769,316
$3,779,253
$3,228,505
$254,399,523
$171,171,039
162
152
94
305
176
11
9
424
363
$69,629,239
$5,365,074
$34,967,066
$26,770,977
$17,499,697
$3,027,966
$2,473,237
$204,853,025
$138,072,854
431
404
250
812
469
30
25
1127
965
$173,420,580
$13,380,685
$87,262,096
$66,740,185
$43,658,297
$7,640,129
$6,542,996
$510,285,782
$343,782,244
Not Analyzed
9
34
21
17
37
16
21
7
11
5
37
16
20
23
11
$761,981
$8,425,928
$10,054,943
$6,515,393
$16,249,287
$7,266,433
$18,036,499
$2,973,199
$4,796,986
$1,670,636
$9,663,677
$3,466,257
$13,474,464
$10,264,391
$1,009,661
95
344
208
169
379
168
215
75
109
56
377
157
199
228
108
$4,045,231
$42,759,490
$49,148,281
$31,370,785
$82,564,796
$38,053,093
$91,172,950
$15,706,604
$24,256,244
$8,956,273
$48,851,355
$16,965,305
$67,911,621
$50,599,974
$5,045,205
63
229
138
112
251
111
143
50
73
37
250
104
132
151
72
$3,245,690
$34,607,789
$39,655,633
$25,164,891
$66,538,067
$30,626,676
$73,564,710
$12,609,113
$19,789,517
$7,255,794
$39,313,469
$13,711,552
$54,648,881
$40,799,589
$4,072,216
167
607
367
298
667
295
379
132
193
98
664
277
351
402
191
$8,052,902
$85,793,207
$98,858,857
$63,051,069
$165,352,151
$75,946,202
$182,774,160
$31,288,916
$48,842,747
$17,882,702
$97,828,501
$34,143,113
$136,034,966
$101,663,954
$10,127,083
-------
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Totals
Transportation
#
Projects
10
14
3
7
7
13
32
11
30
28
12
27
0
27
14
22
103
14
1
25
21
6
13
5
0
988
Total cost ($)
$3,602,478
$407,172
$1,025,139
$3,960,890
$824,031
$4,862,707
$16,991,295
$1,305,281
$13,129,936
$6,997,738
$4,563,317
$10,884,586
~
$9,166,690
$2,263,821
$7,482,722
$25,255,152
$1,552,194
$577,339
$10,559,242
$5,639,595
$2,176,899
$4,402,884
$751,962
~
$379,002,205
Residential
#
Projects
102
137
30
71
78
129
315
109
292
281
122
268
6
271
140
220
1029
140
9
255
215
59
127
47
2
9,899
Total cost ($)
$17,537,778
$1,965,536
$4,493,388
$19,841,487
$4,540,554
$24,839,333
$83,503,502
$6,600,231
$63,428,448
$34,656,220
$22,585,641
$54,377,034
$1,511,512
$46,345,930
$11,185,553
$38,172,832
$125,859,943
$7,669,400
$1,696,162
$53,929,973
$28,507,669
$11,522,196
$22,152,966
$3,382,569
$201,966
$1,891,979,488
Nonresidential
#
Projects
67
91
20
47
52
86
209
73
194
187
81
178
4
180
93
145
684
94
6
169
143
40
84
31
0
6,570
Total cost ($)
$13,976,862
$1,590,727
$3,680,590
$15,915,456
$3,644,228
$20,206,898
$67,367,869
$5,384,815
$51,204,463
$28,045,802
$18,121,919
$43,918,177
$1,338,160
$37,426,485
$9,049,679
$30,524,474
$101,627,167
$6,236,950
$1,448,836
$43,462,256
$23,001,980
$9,542,571
$17,847,878
$2,711,764
~
$1,525,538,727
TOTALS
#
Projects
179
242
53
125
137
228
556
193
516
496
215
473
10
478
247
387
1816
248
16
449
379
105
224
83
2
17,457
Total costs ($)
$35,117,118
$3,963,436
$9,199,117
$39,717,833
$9,008,812
$49,908,938
$167,862,666
$13,290,327
$127,762,847
$69,699,760
$45,270,877
$109,179,796
$2,849,672
$92,939,104
$22,499,052
$76,180,028
$252,742,262
$15,458,544
$3,722,337
$107,951,471
$57,149,245
$23,241,666
$44,403,728
$6,846,295
$201,966
$3,796,520,420
-------
Section 9: Estimating Incremental Costs for the Proposed Regulation
9.5. REFERENCES
CSQA (California Stormwater Quality Association). 2003. Stormwater BMP Handbook:
Construction. California Stormwater Quality Association, Menlo Park, CA.
.
SWRPC (Southeastern Wisconsin Regional Planning Commission). 1991. Costs of Urban
Nonpoint Source Water Pollution Control Measures. Technical Report No. 31. Southeastern
Wisconsin Regional Planning Commission, Waukesha, WI.
USDA (U.S. Department of Agriculture). 1986. Urban Hydrology for Small Watersheds.
Technical Release 55 (TR55). U.S. Department of Agriculture, Washington, DC.
USEPA (U.S. Environmental Protection Agency). 1993. Guidance Specifying Management
Measures for Sources of Nonpoint Pollution in Coastal Waters. EPA-840-B-92-002. U.S.
Environmental Protection Agency, Office of Water, Washington, DC.
Page 9-54
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Section 11: Estimating Pollutant Load Reductions
10. ESTIMATING POLLUTANT LOAD REDUCTIONS
10.1. OVERVIEW OF APPROACH
The U.S. Environmental Protection Agency (EPA) based its analysis of construction and
development (C&D) site pollutant loads on 1 year's worth of construction acreage and assumes
the average construction duration as either 9 months or 12 months, depending on the model
project.5 Any controls/technologies evaluated by EPA are assumed to be employed for the entire
construction period for purposes of estimating load reductions.
In general, reductions in pollutant loads are derived on the basis of a critical size particle, or the
smallest particle that reasonably is expected to be captured by a control/technology at a site. The
percentage of eroded material captured is determined on the basis of the fraction of eroded soil
larger than the critical particle. Any C&D site soils eroded that are smaller than the critical
particle size are discharged from the site.
EPA used regional estimates of per-acre eroded soil (based on 11 indicator cities) with state-
specific levels of controls to estimate per-state pollutant discharges. The sum of individual state
discharges provides the national total estimate of pollutant discharges under current (baseline)
conditions and under the options considered. The load allocation spreadsheet is DCN 43091 and
the spreadsheet estimating construction site loads is DCN 43092 in the Administrative Record.
10.2. ANALYSIS OF SOIL CHARACTERISTICS BY REGION
EPA used estimates of soil characteristics for a number of indicator cities to characterize broader
soil types across the nation. This case-study approach, while limited in its coverage, does provide
sufficient information for EPA to generally estimate pollutant generation and load reductions
nationwide. EPA expects to collect additional data to better characterize soil characteristics
across the United States to update the model to operate at a Reach File Version 1.0 (RFl)-level
scale. However, this analysis was not complete at the time of proposal.
As discussed in Section 3.5.4, EPA used U.S. Department of Agriculture's (USDA's) STATSGO
soil database to help evaluate the question of how much and what size soil is originating from
C&D sites. As shown in Table 10-1, EPA used STATSGO to inventory soils present on between
0.5 million and 5 million acres in the area surrounding each indicator city. The intent was to
identify soil types and soil characteristics in each city's developing fringe. Nationally, 2,175
STATSGO statistical units were individually evaluated, in combination providing soil data for
20 million acres. The soils at each indicator city were represented by between 74 and 501
STASTSGO statistical units. The STATSGO soil data evaluation is DCN 43096 in the
Administrative Record.
5 Note that EPA's cost analysis assumed a 9-month project duration. Because of an oversight, the load analysis
assumed a 9-month duration for some projects and a 12-month duration for other projects.
Page 10-1
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-1. Summary of STATSGO Evaluation of Indicator City Locations
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Grand Total
Total acreage extracted from
STATSGO representing the
indicator city
720,741
5,311,422
465,617
2,676,561
3,054,633
1,344,782
1,924,721
858,166
484,354
814,413
2,580,084
20,235,494
Number of STATSGO
statistical units evaluated
239
130
93
501
161
151
268
100
101
74
357
2,175
Table 10-2 indicates the dominant or common soil texture classes/surface covers reported by
STATSGO for the area evaluated surrounding each indicator city. As expected, the dominant soil
classes vary among the cities.
Table 10-2. Indicator City Surface Soil Characterization
Indicator
city
Albany, NY-
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City,
KS
Las Vegas,
NV
Manchester,
NH
Seattle, WA
Washington,
DC
Percent of land area for the common soil texture classes 1>2
C
0.0%
0.0%
0.0%
0.0%
44.6%
1.7%
0.0%
0.0%
0.0%
0.0%
0.0%
CL
0.0%
8.6%
0.0%
1.1%
15.3%
22.7%
3.0%
2.5%
0.0%
0.0%
0.5%
L
3.4%
6.1%
40.2%
8.7%
3.2%
19.8%
0.6%
2.5%
0.0%
22.0%
14.7%
LS
9.2%
0.0%
5.1%
4.5%
3.3%
6.2%
0.4%
3.7%
17.7%
2.2%
3.1%
RO
0.7%
0.0%
1.2%
0.0%
0.0%
2.1%
1.5%
0.5%
2.7%
0.6%
0.8%
S
0.0%
0.0%
0.0%
1.1%
0.0%
0.0%
0.0%
0.0%
0.1%
0.4%
0.0%
SCL
0.0%
27.4%
0.0%
0.0%
0.0%
0.0%
0.0%
0.3%
0.0%
0.0%
0.0%
SIC
0.0%
0.0%
0.0%
1.0%
11.4%
0.0%
3.3%
0.0%
0.0%
0.0%
2.4%
SICL
6.7%
0.0%
0.9%
21.1%
2.2%
0.1%
33.8%
0.5%
0.0%
1.3%
11.0%
SIL
74.4%
0.4%
24.7%
60.2%
0.2%
0.2%
52.4%
1.9%
0.2%
20.7%
47.0%
SL
5.6%
57.5%
27.9%
2.3%
19.9%
47.2%
5.1%
88.1%
79.3%
52.8%
20.3%
1 USDA STATSGO Definitions: C = Clay, CL = Clay loam, L = Loam, LS
Sand, SCL = Sandy Clay Loam, SIC = Silty Clay, SICL = Silly Clay Loam,
2 Infrequent/less common soil classes are included in computed percentages.
= Loamy Sand, RO Rock Outcrop, S =
SIL = Silt Loam, SL = Sandy Loam.
Page 10-2
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-3 presents a summary of key STATSGO soil data for each indicator city. The data
shown are spatially averaged, such that soil parameter values representing larger areas have a
greater influence than values representing smaller areas. Some of the Table 10-3 data serve as a
basis for developing hybrid soil particle size distributions for each indicator city (for more
detailed information, see Appendix F - Evaluating Soil Nature and Soil Erosion Representative
of Major U.S. Metropolitan Areas). The indicator city-specific hybrid soil particle size
distribution is the distribution obtained if all soil texture classes surrounding each indicator city
(as shown in Table 10-2) are homogenized into a single composite soil. As a result, it represents
the collective array of particle sizes, proportional to their presence at each indicator city.
Table 10-3. Summary of STATSGO Soil Data Extraction for Indicator Cities
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Average
clay
percentag
e
17%
19%
17%
24%
38%
19%
27%
12%
6%
10%
16%
Average
silt
percentage
43%
26%
41%
57%
35%
25%
66%
16%
33%
31%
39%
Average
sand
percentag
e
40%
55%
43%
20%
27%
56%
7%
72%
61%
59%
45%
Average
RUSLE
K1
0.37
0.26
0.34
0.31
0.33
0.27
0.33
0.31
0.23
0.29
0.33
Average
percent passing
#200 sieve (sub-
75 microns)2
60%
45%
57%
80%
73%
44%
93%
28%
39%
41%
55%
Average
percent passing
#40 sieve (sub-
300 microns)2
75%
77%
76%
92%
89%
63%
96%
47%
62%
58%
74%
1 The Revised Universal Soil Loss Equation (RUSLE) K is a soil credibility factor that represents both susceptibility
of soil to erosion and the rate of runoff. Generally, soils high in clay and coarse textured tend to have low K values.
Soils having a high silt content are the most erodible of all soils and tend to have higher K values
2 Percent Passing values are equal to the percent of the total soil sample (by weight) that is smaller than the opening
of the sieve. As a result it is possible to estimate the fraction of a soil sample that is larger or smaller based on the
sieve used by the soil laboratory to process the soil sample.
STATSGO reports some soil parameters only in terms of a low and a high value, or the range
observed when more detailed data sources were compiled. For example, for each of the 239
statistical units for Albany, STATSGO provides the lowest-reported and highest-reported values
for some soils parameters. Where STATSGO provides a range of values, EPA generally used the
average of the high and low values in subsequent computations (e.g., the average values
provided in Table 10-3).
As discussed in Section 10.3, EPA used the Revised Universal Soil Loss Equation (RUSLE) to
estimate annual soil yield from construction sites. The ^factor (soil erosivity) is an important
parameter in RUSLE, and STATSGO provides location-specific values in its dataset. Table 10-3
indicates the spatially averaged K computed for each of the indicator cities.
Page 10-3
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-4 indicates spatially averaged lowest-reported and highest-reported slope data, and
presents slope values EPA computed from the STATSGO data. The lowest-reported and highest-
reported slopes indicate the extremes, but not the more common conditions likely to occur in a
given area. Therefore, EPA computed three slopes values from the STATSGO datavalues that
reflect regional slope tendencies but offer a more central estimate of the slopes expected to occur
at construction sites.
Table 10-4. Slope Ranges from STATSGO and Computed Regional Slope Ranges for
Estimating Soil Erosion Yield
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
STATSGO reported
(percent)
Average of
lowest reported
slopes
4.72%
7.55%
7.71%
2.39%
1.17%
3.38%
4.26%
5.60%
3.24%
10.89%
6.59%
Average of
highest
reported slopes
12.06%
15.18%
18.71%
6.25%
5.62%
17.83%
8.87%
16.98%
9.59%
25.76%
14.74%
Computed slopes
(percent)
Low end
6.55%
9.46%
10.46%
3.35%
2.28%
6.99%
5.41%
8.45%
4.83%
14.60%
8.63%
Average
8.39%
11.37%
13.21%
4.32%
3.40%
10.61%
6.57%
11.29%
6.42%
18.32%
10.67%
High end
10.22%
13.28%
15.96%
5.28%
4.51%
14.22%
7.72%
14.14%
8.00%
22.04%
12.71%
For its analysis, EPA used the average of the lowest-reported and highest-reported slope values
for each indicator city to produce an average estimate of soil slope/erosion. A low-end estimate
of soil erosion was computed on the basis of the value halfway between the lowest-reported
slope value and the computed average slope value. A high-end estimate of soil erosion was
computed on the basis of the value halfway between the highest-reported slope value and the
computed average slope value.
For most of its analysis of the C&D industry, EPA used the computed average slope value for
each region to obtain a central estimate. The computed low-end and high-end slope values
provide an indication of how natural and geographic variation may affect any results.
10.3. ESTIMATION OF SOIL EROSION RATES
Table 10-5 summarizes the data sources EPA used to obtain indicator city-specific RUSLE
factors customized to the nine construction model projects described in Section 9.3.1. Further
details of EPA's RUSLE application are provided in Appendix F - Evaluating Soil Nature and
Soil Erosion Representative of Major U.S. Metropolitan Areas.
Page 10-4
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-5. Data Sources and Data Processing to Obtain RUSLE Factors
RUSLE
term
C
P
K
R
LS
Definition
Cover-
management
Factor
Support Practice
Factor
Soil Erodibility
Factor
Rainfall-Runoff
Erosivity Factor
Slope Length
Factor
Source of information
SEDCAD 4 Documentation1
SEDCAD 4 Documentation1
STATSGO2
RUSLE2 Database3
Length factor obtained
through assessment of model
project geometry; regional
slope ranges obtained from
STATSGO2
Processing for model project erosion
estimation
Globally set to a value of 1 .0 across all
indicator cities and model projects. This
value is for a denuded soil surface.
Globally set to a value of 0.9 across all
indicator cities and model projects. This
value represents a. Roughed and Irregularly
Tracked soil surface.
Spatially averaged value determined from
soils data for each indicator city.
Value provided for indicator city used the R
reported for the specific city. If not available,
then the R reported for an adjacent county
was used.
Length and regional slope values were
combined to determine LS value, on the basis
of the assumption of a high ratio of rill -to-
interrill erosion.
1 SEDCAD 4 Documentation (Warner et al. 1999)
2 STATSGO Soil Data Coverage
3 RUSLE 2 ARS Version Jan 19 2005, Program Database
Tables 10-6a through 10-6d provide EPA's estimates of erosion rates (low-end, average, and
high-end) for the 11 indicator cities. Note that the per acre erosion rates are the same for large
transportation, medium transportation and small transportation model projects. This occurs
because the overland flow length selected for modeling are the same across these models (200
feet). Matching overland flow length is the reason why the per acre yield estimates match for
small residential and small nonresidential model projects. Each of the model projects predict a
different amount of eroded soil discharge at their outlet points, even if they have the same yield
per acre rate. This occurs because the median site size differs between the nine model
construction projects.
Page 10-5
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-6a. Estimated Soil Eroded from Large Transportation, Medium Transportation
and Small Transportation Model Construction Projects (Tons Per Acre)
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Low-end estimate
47.05
159.12
5.09
28.80
34.77
10.70
73.38
6.32
21.18
82.42
96.50
Average estimate
62.03
211.69
7.20
37.97
53.15
18.59
90.99
9.78
29.04
112.12
133.58
High-end estimate
82.98
265.75
9.38
47.46
72.45
29.58
109.07
13.55
37.19
142.41
173.39
Table 10-6b. Estimated Soil Eroded from Large and Medium Residential Model
Construction Projects (Tons Per Acre)
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Low-end estimate
65.72
229.69
7.41
37.88
44.19
15.04
100.76
9.04
28.79
123.69
138.15
Average estimate
89.58
310.64
10.71
51.10
70.00
27.11
127.13
14.34
40.48
171.70
194.91
High-end estimate
120.62
395.42
14.19
65.03
97.97
42.79
154.60
20.28
52.88
221.73
256.99
Page 10-6
-------
Section 11: Estimating Pollutant Load Reductions
Table 10-6c. Estimated Soil Eroded from Large and Medium Nonresidential Model
Construction Projects (Tons Per Acre)
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Low-end estimate
73.79
260.88
8.45
41.66
48.03
16.92
112.47
10.23
32.02
142.39
156.46
Average estimate
100.24
354.85
12.30
56.64
77.02
30.90
142.76
16.37
45.43
199.06
222.21
High-end estimate
137.33
453.87
16.39
72.54
108.64
49.21
174.49
23.32
59.75
258.54
294.57
Table 10-6d. Estimated Soil Eroded from Small Nonresidential and Small Residential
Model Construction Projects (Tons Per Acre)
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Low-end estimate
53.75
184.20
5.91
32.12
38.26
12.26
83.27
7.29
23.94
96.90
111.34
Average estimate
71.50
246.67
8.44
42.75
59.32
21.60
103.97
11.39
33.15
132.89
155.30
High-end estimate
96.33
311.38
11.07
53.81
81.68
33.57
125.57
15.92
42.79
169.91
202.85
When RUSLE is applied to an agricultural situation, and/or where the slope length is long, it is
expected that some eroded soil particles will deposit as they move along the flow path. Such is
the case where water flow moves eroded particles along a crop row cut into a farm field's
topographic contour. The rough bottom and flat slope at the base of the row provides opportunity
for the recapture of eroded soil particles. The ratio of soil discharged to eroded (moved) soil is
referred to as the delivery ratio.
For C&D sites, EPA elected to assume a delivery ratio of 1 (i.e., 100 percent of the eroded soil
particles would be transported to sediment controls). For construction sites this is justified in part
by the tendency to install efficient flow systems (e.g., drainage channels and conduits) that are
Page 10-7
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Section 11: Estimating Pollutant Load Reductions
designed to convey flow efficiently to sediment controls and off of the site. This convention
helps ensure the construction site work schedule is affected as little as possible by precipitation.
EPA acknowledges that many types of construction site controls, (e.g., silt fences and check
dams) do capture some sand and silt-sized and larger soil particles when they are properly placed
and maintained within the flow path. Therefore, a delivery ratio of 1 would tend to overestimate
the quantity of these larger particles reaching sediment basins. However, because EPA's model
estimates removals on the basis of a specific particle size, removal of these larger particles are
accounted for in EPA's baseline analysis of existing industry practices. However, fine silt and
clay-sized particles are less likely to be removed by conventional erosion and sediment controls.
Therefore, EPA is assuming a delivery ratio of 1 is appropriate.
Table 10-7 shows the range of average yield per acre in terms of clay, silt, and sand fractions
across all model construction projects; values that are based on the average slope for each
indicator city. In general, the larger the particle size, the easier it is to remove with controls that
employ settling (e.g., sediment basins). Where clays and silts dominate, technologies that either
provide extended duration settling or provide assisted settling or filtration (i.e., active treatment
systems) are likely required to obtain high percentages of removal.
Table 10-7. Estimated Range of Average Annual Construction Site Yield for Model
Construction Projects
Indicator city
Albany, NY
Atlanta, GA
Boise, ID
Chicago, IL
Dallas, TX
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
Seattle, WA
Washington, DC
Tons of clay per
acre per year
13-23
50-86
1-3
10-17
18-41
3-9
30-47
1-3
2-4
14-26
25-47
Tons of silt per
acre per year
32-59
68-118
3-7
24-41
17-38
4-12
74-115
2-4
11-20
44-80
61-115
Tons of sand per
acre per year
30-55
143-250
4-7
8-15
13-29
9-28
8-12
7-17
20-36
84-153
70-133
Tons of all soil
particles per
acre per year
74-137
261-454
8-16
42-73
48-109
17-49
112-174
10-23
32-60
142-259
156-295
Table 10-7 also shows the influence of climate on construction site soil yield. In general, the
dryer the climate, the lower the soil yields. Climates like Denver, Colorado, and Las Vegas,
Nevada, are expected to produce order-of-magnitude lower levels of estimated construction site
yield than wetter climates like Atlanta, Georgia.
EPA used the estimates of construction site soil erosion for the 11 indicator cities as point
estimates for surrounding states. Table 10-8 lists the states/commonwealths represented by each
Page 10-8
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Section 11: Estimating Pollutant Load Reductions
of the indicator cities. This analysis does not include consideration of construction activities in
Hawaii and Alaska and does not evaluate any of the U.S. territories.
Table 10-8. Allocation of States/Commonwealths/Territories to Representative Indicator City
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
Indicator city
Atlanta, GA
Las Vegas, NV
Dallas, TX
Las Vegas, NV
Denver, CO
Manchester, NH
Washington, DC
Atlanta, GA
Atlanta, GA
Boise, Id
Chicago, IL
Chicago, IL
Kansas City, KS
Kansas City, KS
Atlanta, GA
Dallas, TX
Manchester, NH
Washington, DC
Manchester, NH
Chicago, IL
Chicago, IL
Atlanta, GA
Kansas City, KS
Denver, CO
Kansas City, KS
Las Vegas, NV
Manchester, NH
State
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Alaska
Hawaii
Puerto Rico
Virgin Islands
Pacific Islands
District of Columbia
Indicator city
Albany, NY
Dallas, TX
Albany, NY
Atlanta, GA
Denver, CO
Chicago, IL
Dallas, TX
Seattle, WA
Washington, DC
Manchester, NH
Atlanta, GA
Denver, CO
Atlanta, GA
Dallas, TX
Denver, CO
Manchester, NH
Washington, DC
Seattle, WA
Washington, DC
Chicago, IL
Denver, CO
Not analyzed
Not analyzed
Not analyzed
Not analyzed
Not analyzed
Washington, DC
Table 10-9 indicates EPA's range of state-specific erosion estimates. The values shown are for
the amount of sediment/soil eroded over the course of construction, before any controls are
implemented. For each state, EPA assumed commercial sites were under construction for 9
months, and transportation and residential model projects were under construction for 12 months.
EPA notes that these values are not consistent with the cost analysis. EPA intends to address this
discrepancy in the analysis in support of the final rule. Table 10-9 values are based on land
development rates for each state (see Section 4.2.2). The per-state values provided are based on
combining the estimated erosion for the nine representative model construction projects in
proportion to their representation of the total constructed acreage (see Section 4.2.2.2).
Page 10-9
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Section 11: Estimating Pollutant Load Reductions
Table 10-9. Estimated Annual Construction Site Soil Erosion by State without Any
Controls (Tons of Sediment)
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Low-end estimate
2,677,452
99,137
303,376
199,374
191,931
23,745
91,860
7,035,985
6,022,396
~
33,728
627,225
378,926
819,781
1,829,978
1,847,692
459,149
104,136
727,199
76,955
687,714
284,889
2,190,787
1,101,274
77,954
493,180
59,257
41,888
227,188
167,391
408,187
3,465,838
79,201
532,390
597,718
725,168
1,779,085
9,039
2,988,373
100,709
2,415,493
Average estimate
3,619,612
157,191
479,765
316,126
345,612
33,360
129,560
9,511,807
8,141,561
~
48,724
845,292
510,661
1,033,744
2,307,564
2,497,868
726,111
146,325
1,025,409
108,130
926,819
383,947
2,961,684
1,388,667
140,382
621,909
93,957
58,853
306,017
264,698
549,837
4,685,375
142,609
717,501
945,275
1,006,263
2,508,754
12,702
4,039,899
181,338
3,265,502
High-end estimate
4,605,936
222,253
670,144
446,975
545,180
43,542
170,785
12,103,674
10,360,053
~
64,535
1,075,040
649,450
1,256,578
2,804,944
3,178,521
1,014,247
191,011
1,351,442
141,149
1,178,733
488,313
3,768,715
1,687,968
221,455
755,976
132,846
76,822
416,467
369,718
748,307
5,962,067
224,947
912,531
1,320,405
1,299,055
3,306,533
16,582
5,140,703
286,039
4,155,365
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Section 11: Estimating Pollutant Load Reductions
State
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Low-end estimate
2,190,671
101,623
13,563
1,686,403
1,273,027
392,908
231,875
34,525
2,881
47,910,224
Average estimate
3,464,421
182,987
19,049
2,378,049
1,766,496
554,024
312,486
62,167
4,071
65,930,155
High-end estimate
4,839,209
288,642
24,858
3,134,251
2,280,503
730,170
397,414
98,060
5,374
85,163,488
10.4. ESTIMATION OF SEDIMENT REMOVAL EFFICIENCIES
When estimating sediment removal efficiencies, EPA considered several factors:
The limits of the technology/controls
Minimum design sizing requirements that affect the volume of construction site
runoff treated, and the degree of treatment provided
The percentage of total construction acreage managed with a technology/control
EPA considered all these factors to estimate state-specific removal efficiencies for current or
baseline controls, and for the regulatory options considered. EPA's proposed option is
specifically designed to remove fine silts and clay-sized particles that, once mobilized, typically
cannot be effectively managed using conventional BMPs that rely on settling. On the basis of
soil characteristics at 11 indicator cities, clays and silts combine to make up between 28 and 93
percent of eroded soil from construction sites.
Estimating the performance of the variety of erosion and sediment controls likely to be employed
at construction sites, given the array of site conditions, site geometries, soil types and rainfall
conditions nationally is an extremely complicated undertaking. Models do exist (such as
SEDCAD and SEDIMOT III) that can be used to estimate, for a given set of site conditions and
for a given storm event, the sediment generation, sediment transport and sediment removals
through BMPs. However, a significant amount of data regarding site conditions, watershed
parameters and design features of various control structures is needed. Given the range of
possible conditions nationally, EPA determined that basing a national loading reductions
estimate on an input parameter-intensive model such as SEDCAD was not feasible for this
analysis. Therefore, EPA developed a relatively straightforward approach to estimate loading
reductions estimates for the regulatory options considered. In summary, EPA's technology
analysis makes the following assumptions to obtain per-state and national reductions:
Pollutant removals are estimated for TSS only, although reductions in other
construction site pollutants associated with sediment, such as nutrients and metals,
will likely occur through the application of control technologies.
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Section 11: Estimating Pollutant Load Reductions
Construction denudes 90 percent of the total site acreage; the remaining portion of the
site is undisturbed.
The entire disturbed area remains disturbed for the duration of the project. (Note that
this likely results in an overestimation of both costs and loads, since projects are
expected to stabilize portions of the site once construction activities have temporarily
or permanently ceased.)
100 percent of construction site runoff is discharged at a single point for sites larger
than 5 acres and 100 percent of eroded material will be transported to sediment basins
for sites larger than 5 acres.
All construction site runoff is processed through sediment basins (i.e., no bypass)
unless specifically noted in the technology application description.
Any proposed technology or design minimums are uniformly applied to residential,
nonresidential, and transportation construction projects unless the technology would
not be required because of site size, R-factor, or soil clay content applicability
provisions.
No adjustments are made to account for poor installation and/or poor maintenance of
controls.
The duration of construction site activities is assumed to be 1 year for residential and
transportation projects and 9 months for commercial projects.6
Technologies/controls are assumed to operate for the entire duration of construction.
The following summarizes EPA's approach to estimating the removal efficiency of individual
sediment basin designs:
Removal of sediment is based on a critical particle size (i.e., the particle that will
settle in a sediment basin for a given storm size)
100 percent of the soil particles larger than the critical particle would be captured, and
100 percent of soil particles smaller than the critical particle are released
The average storm intensity for the 10-year, 6-hour storm event (one selected for each
state) is the basis for estimating the critical particle size for each sediment basin design
The average annual removal efficiency for all events is equal to the removal
efficiency computed given the average intensity for the 10-year, 6-hour event
6 EPA's costing analysis assumed a 9-month duration for small transportation projects. Because of an oversight, the
loadings methodology did not incorporate these assumptions. As a result, the loading estimates for the small
transportation model projects are overestimates, because they are based on a 12-month duration. However, because
these projects comprise only a small amount of national developed acres, the error in the national loadings estimates
are small (less than 1 percent). EPA intends to correct this oversight for the analysis in support of the final rule.
Page 10-12
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Section 11: Estimating Pollutant Load Reductions
EPA determined the critical particle size for one indicator city in each state using Stokes' Law
and the approach contained in the January 2003 California Stormwater Quality Association's
(CSQA's) California Stormwater Best Management Practices Handbook - Construction
(http://www.cabmphandbooks.com/Construction.asp) for designing sediment basins. The CSQA
handbook provides a process for relating a design flow rate, a critical particle size, and the
sediment basin volume.
The CSQA standard is based on the settling velocity of particles as determined by Stokes' Law,
which states that the settling velocity (Fc) is a function of the density of the particle (ps) and the
fluid (/>/), the acceleration due to gravity (g), the diameter of the particle (d) and the dynamic
viscosity of the fluid (ju).
18//
Stokes' Law is generally valid for Reynolds numbers less than 1 (quiescent conditions) and for
spherical particles.
After the settling velocity of the design particle size is determined (called the terminal settling
velocity), sediment basins can be sized so that all particles with a settling velocity equal to or
greater than the terminal velocity can be removed. This is accomplished by calculating the
surface area (^4) of the basin for a specified flow rate (Q) using the following equation:
Vc
The calculation is based on the terminal settling velocity for a design particle size, and the design
flowrate is based on the 10-year, 6-hour rainfall event. The option described in the CSQA
manual is illustrated in Figure 10-1.
Using this methodology, EPA calculated the critical particle size that would be removed in one
indicator city in each state on the basis of the rainfall intensity for the 10-year, 6-hour storm
event. Basin volumes were based on the current requirements for sediment basin sizing contained
in each state's general permit. EPA used a particle density of 2,650 kg/m3, a fluid density of
1,000 kg/m3, a dynamic viscosity of 0.001 kg/m-s, and a sediment basin depth of 6 feet for all
calculations. The runoff coefficient used in each state was the runoff coefficient calculated for
the 10-year, 6-hour storm event (see Table 9-4). Table 10-10 summarizes the critical particle size
removed in each state for the 10-year, 6-hour storm event under current state baseline conditions.
Table 10-11 summarizes the critical particle size removed in each state for the 10-year, 6-hour
event given the sediment basin sizing criteria contained in Option 1 (smaller than the 2-year, 24-
hour storm runoff or 3,600 cubic feet per acre [cf/acre]). As mentioned above, EPA assumed that
the critical particle size removed for all storm events under baseline conditions and under Option
1 is equal to the critical particle size removed for the 10-year, 6-hour storm event any particles
smaller than the critical particle size would pass through the sediment basin and be discharged.
Page 10-13
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Section 11: Estimating Pollutant Load Reductions
Sediment basin(s) shall be designed using the standard equation:
A,= \.2QIV,
where:
As = Minimum surface area for trapping soil particles of a certain size
Vs = Settling velocity of the design particle size chosen
Q = CIA
where
Q = Discharge rate measured in cubic feet per second
C = Runoff coefficient
/ = Precipitation intensity for the 10-year, 6-hour rain event in inches per hour
A = Area draining into the sediment basin in acres
Figure 10-1. CSQA Settling Velocity Criteria for Sizing Sediment Basins
Table 10-10. Critical Particle Sizes Removed Under Baseline Conditions.
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Indicator city
Montgomery
Phoenix
Little Rock
Sacramento
Denver
Hartford
Dover
Tallahassee
Atlanta
Honolulu
Boise
Chicago
Indianapolis
Des Moines
Kansas City
Frankfort
Baton Rouge
Augusta
Baltimore
Boston
Lansing
St. Paul
Jackson
Baseline
sediment basin
volume
(cf/acre)
1,800
3,600
3,600
3,660
1,800
3,600
3,600
3,600
1,800
12,868
3,600
6,494
1,800
3,600
3,600
3,600
3,600
3,600
3,600
7,307
3,600
6,172
3,600
10-year, 6-
hour storm
depth (inches)
4.60
1.57
4.35
1.70
2.30
3.25
3.44
5.25
4.20
4.80
1.20
3.30
3.12
3.54
3.90
3.09
5.75
2.90
3.32
3.30
2.70
3.10
4.70
10-year, 6-
hour storm
intensity
(in/hr)
0.77
0.26
0.73
0.28
0.38
0.54
0.57
0.88
0.70
0.80
0.20
0.55
0.52
0.59
0.65
0.52
0.96
0.48
0.55
0.55
0.45
0.52
0.78
Critical
particle size
removed
(microns)
27.5
9.2
19.4
9.5
16.9
15.3
15.9
21.7
25.8
10.7
7.0
11.7
21.7
16.3
17.4
15.1
23.3
14.8
15.7
11.1
13.0
11.5
20.1
Page 10-14
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Section 11: Estimating Pollutant Load Reductions
State
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of
Columbia
Indicator city
Kansas City
Helena
Lincoln
Las Vegas
Manchester
Hightstown
Santa Fe
Albany
Charlotte
Bismarck
Columbus
Oklahoma City
Salem
Philadelphia
Providence
Columbia
Pierre
Nashville
Fort Worth
Salt Lake City
Montpelier
Arlington
Seattle
Charleston
Madison
Cheyenne
San Juan
District of
Columbia
Baseline
sediment basin
volume
(cf/acre)
3,600
1,800
1,800
3,600
6,333
1,800
3,600
3,600
1,800
3,600
1,800
9,296
3,600
5,000
1,800
13,168
3,600
8,196
9,969
3,600
1,800
3,600
3,600
3,600
2,770
1,800
1,800
7,503
10-year, 6-
hour storm
depth (inches)
3.85
1.10
3.52
1.29
3.20
3.55
1.77
3.10
3.54
2.50
2.80
4.25
2.90
3.38
3.40
3.85
2.75
3.31
4.55
1.27
2.70
3.29
1.40
2.56
3.15
1.90
4.42
3.32
10-year, 6-
hour storm
intensity
(in/hr)
0.64
0.18
0.59
0.22
0.53
0.59
0.30
0.52
0.59
0.42
0.47
0.71
0.48
0.56
0.57
0.64
0.46
0.55
0.76
0.21
0.45
0.55
0.23
0.43
0.53
0.32
0.74
0.55
Critical
particle size
removed
(microns)
17.6
9.5
21.3
8.1
11.7
23.3
10.0
15.2
23.1
12.7
20.7
11.6
14.5
13.6
22.2
9.1
14.1
10.5
11.7
7.8
19.8
15.5
7.8
13.3
17.5
15.1
27.0
11.0
Table 10-11. Critical Particle Sizes Removed Under Option 1
State
Alabama
Arizona
Arkansas
California
Colorado
3,600 cubic feet per
acre Basin (microns)
19.4
9.2
19.4
9.7
12.0
2-year, 24-hour
Runoff Basin
(microns)
10.7
11.7
11.0
9.3
11.8
Page 10-15
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Section 11: Estimating Pollutant Load Reductions
State
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
3,600 cubic feet per
acre Basin (microns)
15.3
15.9
21.7
18.3
20.2
7.0
15.9
15.3
16.3
17.4
15.1
23.3
14.8
15.7
15.4
13.0
15.2
20.1
17.6
6.7
15.0
8.1
15.1
16.4
10.0
15.2
16.3
12.7
14.6
18.5
14.5
16.0
15.7
17.2
14.1
15.7
19.8
7.8
14.0
15.5
7.8
13.3
2-year, 24-hour
Runoff Basin
(microns)
11.0
11.0
11.3
11.5
10.7
10.6
11.7
11.0
11.2
11.4
10.8
11.2
10.8
11.0
11.1
11.6
11.5
11.0
11.4
9.1
12.0
13.2
11.7
11.1
11.9
11.1
11.0
13.1
11.1
11.6
11.8
10.9
11.1
11.0
12.2
10.5
11.7
9.7
11.5
11.0
7.8
10.6
Page 10-16
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Section 11: Estimating Pollutant Load Reductions
State
Wisconsin
Wyoming
Puerto Rico
District of Columbia
3,600 cubic feet per
acre Basin (microns)
14.8
10.7
19.1
15.7
2-year, 24-hour
Runoff Basin
(microns)
11.5
12.1
10.8
11.0
To translate the critical particle size removed into loading reduction estimates for the regulatory
options, EPA estimated the proportion of each state's sediment load that would be above and
below the critical particle size on the basis of the hybrid particle size distributions developed
from the soils data collected for each of the 11 indicator cities described in Section 10.3. As
described in Appendix G, EPA used data from STATSGO to determine the percent of sand, silt
and clay present in the surface soils in the area surrounding each indicator city. Using an
approach described by Skaggs et al. (2001), EPA developed particle size distributions from the
STATSGO data. Figure 10-2 illustrates the particle size distributions developed from the
STATSGO data for each of the 11 indicator cities. By comparing the critical particle size
removed for a given sediment basin criteria with the particle size distribution for the given
indicator city, EPA was able to estimate the percentage of soil by mass that would be larger and
smaller than the critical particle size. For example, Figure 10-3 illustrates the incremental
removal for Georgia when increasing sediment basin size from a baseline of 1,800 cf/acre to
either 3,600 cf/acre or runoff from the 2-year/24-hour storm. Under baseline conditions,
approximately 35.4 percent of the soil particles are less than 25.8 microns, which is the critical
particle size for a 1,800 cf/acre basin. For a 3,600 cf/acre basin, the critical particle size removed
is 18.3 microns. Approximately 33.3 percent of the soil particles are smaller than 18.3 microns.
So, when moving from a baseline basin to a 3,600 cf/acre basin, approximately 2.1 percent of the
soil mass would be removed. The critical particle size for a 2-year/24-hour runoff basin is 11.5
microns, which corresponds to approximately 30.9 percent finer. This corresponds to 4.5 percent
of the soil mass being removed over baseline conditions.
Page 10-17
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Section 11: Estimating Pollutant Load Reductions
100
10 100
Particle Size (microns)
1000
-Albany, NY - Atlanta, Ga ABoise, Id --Chicago, I. SK Dallas, Tx
-Kansas City, Ks B Las Vegas, Nv Manchester, NH « Seattle, Wa Wash. DC
-Denver, Co
Figure 10-2. Indicator City Soil Particle Size Distributions.
Page 10-18
-------
Section 11: Estimating Pollutant Load Reductions
inn
an
sn
70.
Rn
i_
-------
Section 11: Estimating Pollutant Load Reductions
EPA also acknowledges that by using the average intensity for the 10-year, 6-hour event to
estimate removal rates, it is potentially underestimating the average annual removal rates for
smaller-intensity storms. It is very probable that all rainfall events during the construction period
will be less intense than the 10-year, 6-hour design event, and many rainfall events will be
completely retained within sediment basins and traps. By using a relatively large storm event
intensity as the basis for estimating removal efficiency for all storm events, the loadings analysis
tends to over-predict the amount of discharged sediment under baseline conditions and under the
regulatory options that rely on sediment basins for most storm events, given average annual
precipitation values. However, this approach likely underestimates sediment discharged for
larger and higher-intensity storm events. The loading analysis also does not account for flows
from large storm events that would overtop the basin and exit via the emergency spillway. There
is also the potential for large variability in baseline loadings estimates, since EPA is using
RUSLE and these calculations are based on average annual conditions. In addition, EPA's
assumptions regarding the percentage of the site that is disturbed and the duration of exposed
soils are important factors in estimating sediment generation (and, incidentally, compliance
costs). Also, by using the parent soil particles size distribution instead of the eroded soil particle
size distribution, EPA is ignoring any differences between soil present on the site and soil that
would actually be eroded and transported. Also, EPA's analysis of soil data looks only at the
surface soil layer. So, any difference between surface soils and soils actually disturbed and
exposed on the site would introduce error. In total, EPA expects that, on average, this approach
provides a reasonable method of estimating removal rates in sediment basins. In actuality, a
number of factors such as basin geometry, water temperature, inlet and outlet configuration,
particle size distribution of eroded sediments, the degree to which the basin has been dewatered,
and the quantity of sediment accumulation present in the basin will affect actual basin
performance. However, modeling all these parameters in detail is not feasible.
To estimate removals for sites implementing turbidity controls under Options 2 and 3, EPA
assumed that, because of the high level of sediment removal attributable to active treatment
systems (ATS), that discharges from ATS would remove essentially all of the sediment
contained in the stormwater runoff from sites implementing turbidity controls for all storm
events up to the 2-year, 24-hour storm event. EPA acknowledges that this results in an
overestimate of the actual removals for sites implementing turbidity controls under Options 2
and 3 because some sediment will still be present in the discharge. However, this approach is
expected to provide a reasonable estimation of the removals attributable to these options. To
estimate removals for individual model projects for Options 2 and 3, EPA estimated the acres
and number of model sites (accounting for the site size, R-factor and clay content applicability
provisions of Option 2) expected to be subject to turbidity controls under these options. By
estimating the percentage of sediment mass below the baseline critical particle size (reflecting
the quantity not removed by baseline sediment basins) and multiplying these state-level estimates
by the per-acre sediment generation for the associated indicator city and the site size estimates
for the model project, EPA was able to estimate the total sediment load removed by these
options. For sites under Option 2 that are not required to meet the turbidity limit but are required
to install larger sediment basins, removals were calculated using the same approach as Option 1.
Table 10-12 indicates the percentage of eroded soil estimated to be released from sediment
basins, which are sized to different design levels. The baseline condition indicates the quantity of
sediment that is estimated to occur for current state design requirements. For some states,
Page 10-20
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Section 11: Estimating Pollutant Load Reductions
baseline releases will match releases estimated for other design standards. For example, Arizona
requires designs based on 3,600 cf/acre, and so Table 10-12 indicates the same percent release in
the second and third columns. Oklahoma requires designs to manage the 2-year, 24-hour event
runoff under baseline conditions, so Table 10-12 indicates the same release in the second and
fourth columns.
Table 10-12. Percent of Eroded Construction Site Sediment Released from Sediment Basins
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Percent of sediment release
Baseline
35.86
18.70
63.74
19.09
34.67
28.08
43.05
34.17
35.37
41.00
67.98
71.65
89.54
89.69
32.31
64.77
27.68
42.91
26.34
68.89
67.90
33.80
89.67
32.42
90.32
18.09
26.51
52.12
60.01
49.52
34.73
33.24
3,600 cu. ft.
per acre
33.74
18.70
63.74
19.11
33.12
28.08
43.05
34.17
33.32
41.00
69.71
69.58
89.54
89.69
32.31
64.77
27.68
42.91
28.12
68.89
69.48
33.80
89.67
31.02
89.50
18.09
27.93
50.06
60.01
49.52
32.77
33.24
Treating 2-yr,
24-hr runoff
30.71
19.40
60.75
19.02
32.98
26.30
40.80
30.89
30.95
43.25
67.98
67.72
88.61
88.63
30.73
60.83
26.27
40.79
26.34
67.90
67.90
30.79
88.64
32.34
88.70
19.60
26.51
47.80
60.96
47.80
30.79
33.27
Capture 10 microns
(diameter) or
greater
30.40
19.09
60.29
19.09
32.45
25.91
40.33
30.40
30.40
42.93
67.22
67.22
88.35
88.35
30.40
60.29
25.91
40.33
25.91
67.22
67.22
30.40
88.35
32.45
88.35
19.09
25.91
47.29
60.29
47.29
30.40
32.45
Capture 20 microns
(diameter) or greater
33.87
21.18
64.12
21.18
35.58
29.49
44.40
33.87
33.87
47.09
71.30
71.30
90.03
90.03
33.87
64.12
29.49
44.40
29.49
71.30
71.30
33.87
90.03
35.58
90.03
21.18
29.49
51.24
64.12
51.24
33.87
35.58
Page 10-21
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Section 11: Estimating Pollutant Load Reductions
State
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of
Columbia
Percent of sediment release
Baseline
71.17
60.96
30.52
42.02
30.17
29.96
33.65
30.62
61.00
31.42
29.16
42.86
28.63
41.89
70.32
33.92
40.79
3,600 cu. ft.
per acre
69.12
63.58
30.52
42.98
28.23
33.07
33.65
32.60
63.83
31.42
27.32
42.86
28.63
41.89
69.55
32.43
42.91
Treating 2-yr,
24-hr runoff
67.75
60.96
29.60
40.78
26.33
30.80
33.11
30.62
61.00
32.49
26.47
40.81
28.49
40.65
67.89
33.05
40.79
Capture 10 microns
(diameter) or
greater
67.22
60.29
29.02
40.33
25.91
30.40
32.45
30.40
60.29
32.45
25.91
40.33
29.02
40.33
67.22
32.45
40.33
Capture 20 microns
(diameter) or greater
71.30
64.12
32.28
44.40
29.49
33.87
35.58
33.87
64.12
35.58
29.49
44.40
32.28
44.40
71.30
35.58
44.40
10.5. CALCULATION OF NATIONAL LOADINGS AND REMOVALS BY
REGULATORY OPTION
To estimate pollutant removals under the regulatory options, EPA compared the baseline
removal estimates with the removal estimates attributable to the specific technology or sizing
criteria. Whenever an existing state baseline requirement was more stringent than a regulatory
option, EPA assumed the state would retain its current requirement (i.e., there would be no
backsliding by states). States with less stringent requirements would upgrade their requirements
to meet the new national regulatory standard.
EPA computed its national estimates of construction site pollutant removals and discharged loads
by doing the following:
Estimating the per-state tonnage of eroded soil for each of the nine model
construction sites (large and small residential, nonresidential, and transportation
projects)
Computing option-specific per-state removals using the more effective of either
baseline controls or the proposed technology/sizing criteria (i.e.; if baseline sizing
was more stringent than the option, the removals for baseline were used)
Page 10-22
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Section 11: Estimating Pollutant Load Reductions
Estimating the per-state construction acreage managed under each regulatory option
after site-size and soil-based applicability criteria were applied (i.e., separating
acreage managed at baseline from that managed with new requirements)
Multiplying the per-state acreage by the appropriate estimated removal rate to first
compute the tons captured and then the tons discharged for baseline conditions and
each regulatory option
Summing baseline and regulatory option-specific per-state values to produce total
national estimates of tons discharged under baseline conditions and incremental
removals and tons discharged for each regulatory option
Table 10-13 provides EPA's estimates for baseline conditions. Note, the low-end and high-end
estimates reflect the influence of construction site land slope (see Table 10-4). EPA analyzed a
range of slopes specific to eleven indicator cities (each of which represents a series of states) to
evaluate the influence of regional variations in site conditions into the assessment of regulatory
options.
Table 10-13. Estimated Annual State Baseline Construction Site Discharged Loads
Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Tons of total suspended solids (TSS) discharged per year
Low-end estimate
960,240
18,539
193,385
38,055
66,549
6,668
39,544
2,403,934
2,130,195
13,829
426,382
271,507
734,051
1,641,291
597,047
297,384
28,822
312,014
20,269
473,775
193,442
740,394
987,488
25,274
Average estimate
1,298,136
29,396
305,823
60,339
119,835
9,368
55,772
3,249,830
2,879,769
19,977
574,622
365,897
925,638
2,069,633
807,139
470,292
40,499
439,965
28,481
638,498
260,704
1,000,925
1,245,187
45,515
High-end estimate
1,651,871
41,563
427,180
85,315
189,031
12,227
73,519
4,135,374
3,664,477
26,460
730,803
465,342
1,125,169
2,515,730
1,027,079
656,914
52,867
579,853
37,178
812,044
331,569
1,273,668
1,513,564
71,801
Page 10-23
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Section 11: Estimating Pollutant Load Reductions
Region
7
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
3
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) discharged per year
Low-end estimate
445,418
10,719
11,105
118,417
100,448
202,130
1,203,557
26,325
378,914
364,364
221,339
747,537
2,727
895,454
33,884
739,655
1,336,326
31,933
3,955
722,808
364,481
164,573
163,061
11,712
1,175
20,922,096
Average estimate
561,679
16,996
15,603
159,506
158,840
272,274
1,627,056
47,400
510,663
576,232
307,137
1,054,130
3,833
1,210,539
61,013
999,939
2,113,323
57,500
5,554
1,019,253
505,767
232,058
219,749
21,088
1,661
28,700,030
High-end estimate
682,762
24,030
20,367
217,075
221,861
370,554
2,070,404
74,767
649,470
804,908
396,504
1,389,341
5,003
1,540,390
96,240
1,272,427
2,951,954
90,701
7,247
1,343,368
652,932
305,839
279,472
33,264
2,192
37,003,670
Comparison of baseline loads (Table 10-12) with values of sediment generation in the absence of
controls (Table 10-9) indicates the per-state and national removal rates for current baseline
requirements. Overall, EPA estimates that current state baseline controls result in a national
reduction of approximately 56 percent of the construction-site eroded soil load.
Table 10-13 presents EPA's estimate of total national TSS releases from construction sites under
three options developed for the proposed rule. Table 10-14 provides EPA's per-state estimates
for the tons of eroded sediment that would be captured for each of the options. Three estimates
are provided for each of the options; estimates reflecting the influence of land slope (i.e., low-
end, average, and high-end slopes).
Page 10-24
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Section 11: Estimating Pollutant Load Reductions
Table 10-13a. Estimated Annual Option 1 Construction Site Discharged Loads
Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
910,336
18,539
193,385
38,055
63,935
6,668
39,544
2,403,934
2,021,762
13,829
426,382
264,667
734,051
1,641,291
597,047
297,384
28,822
312,014
20,269
473,775
193,442
740,394
987,488
25,220
441,892
10,719
11,105
114,297
100,448
202,130
1,143,920
26,325
369,366
364,364
221,339
747,537
2,574
895,454
33,884
739,655
Average estimate
1,230,580
29,396
305,823
60,339
115,115
9,368
55,772
3,249,830
2,732,984
19,977
574,622
356,662
925,638
2,069,633
807,139
470,292
40,499
439,965
28,481
638,498
260,704
1,000,925
1,245,187
45,417
557,227
16,996
15,603
153,946
158,840
272,274
1,546,328
47,400
497,770
576,232
307,137
1,054,130
3,616
1,210,539
61,013
999,939
High-end estimate
1,565,810
41,563
427,180
85,315
181,570
12,227
73,519
4,135,374
3,477,485
26,460
730,803
453,579
1,125,169
2,515,730
1,027,079
656,914
52,867
579,853
37,178
812,044
331,569
1,273,668
1,513,564
71,645
677,344
24,030
20,367
209,498
221,861
370,554
1,967,563
74,767
633,047
804,908
396,504
1,389,341
4,721
1,540,390
96,240
1,272,427
Page 10-25
-------
Section 11: Estimating Pollutant Load Reductions
Region
6
8
1
3
lOb
3
5
8
3
State
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
1,336,326
31,933
3,735
722,808
364,481
164,573
161,493
11,448
1,175
20,675,215
Average estimate
2,113,323
57,500
5,245
1,019,253
505,767
232,058
217,631
20,613
1,661
28,364,884
High-end estimate
2,951,954
90,701
6,843
1,343,368
652,932
305,839
276,775
32,512
2,192
36,574,844
Tons of TSS discharged annually after reductions due to current state required construction site controls.
Table 10-13b. Estimated Annual Option 2 Construction Site Discharged Loads
Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
475,718
17,234
69,908
34,450
56,532
4,816
32,087
2,389,759
1,154,208
13,829
150,812
111,336
256,726
655,301
208,809
140,904
15,872
140,723
18,982
374,347
110,008
302,068
353,800
25,220
261,604
Average estimate
642,241
27,321
109,960
54,611
101,743
6,761
45,239
3,230,641
1,558,587
19,977
202,536
149,631
322,866
824,538
281,586
222,080
22,263
198,057
26,668
504,244
148,043
407,567
444,984
45,417
329,553
High-end estimate
816,311
38,625
153,008
77,202
160,432
8,819
59,617
4,110,929
1,981,401
26,460
256,870
189,884
391,586
1,000,455
357,568
309,465
29,023
260,627
34,808
641,042
188,067
517,779
539,732
71,645
400,258
Page 10-26
-------
Section 11: Estimating Pollutant Load Reductions
Region
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
3
State
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
10,719
9,590
80,640
98,910
100,534
569,177
14,603
134,411
143,079
152,594
262,172
1,896
698,055
13,600
259,677
578,523
31,933
1,385
306,259
282,135
58,231
97,924
11,448
650
11,293,197
Average estimate
16,996
13,469
108,528
156,401
135,173
768,311
26,229
180,515
225,213
211,588
368,637
2,662
943,325
24,377
350,189
911,270
57,500
1,938
430,958
391,315
81,880
131,801
20,613
915
15,486,916
High-end estimate
24,030
17,577
147,600
218,447
183,694
976,440
41,302
228,948
313,538
272,992
484,715
3,473
1,199,984
38,330
444,690
1,269,302
90,701
2,522
567,018
504,985
107,665
167,454
32,512
1,204
19,960,737
Tons of TSS discharged annually after reductions due to current state required construction site controls.
Table 10-13c. Estimated Annual Option 3 Construction Site Discharged Loads
Region
4
9
6
9
8
1
3
4
4
lOa
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
116,014
2,253
25,217
4,627
8,151
815
4,745
290,328
257,369
1,661
Average estimate
155,311
3,517
39,071
7,224
14,357
1,128
6,616
388,670
344,547
2,369
High-end estimate
196,001
4,914
53,777
10,092
22,295
1,456
8,639
490,497
434,814
3,106
Page 10-27
-------
Section 11: Estimating Pollutant Load Reductions
Region
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
3
State
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) discharged per year1
Low-end estimate
54,335
34,563
91,377
204,147
71,996
38,650
3,610
37,930
2,529
60,435
24,703
89,460
122,752
3,108
55,490
1,305
1,384
14,496
13,036
24,970
145,235
3,236
48,272
47,423
26,169
90,853
340
108,136
4,153
89,290
173,786
3,918
466
87,599
42,992
19,844
20,715
1,431
335
2,575,647
Average estimate
72,269
45,970
114,061
254,825
96,383
59,884
4,997
52,886
3,500
80,382
32,856
119,763
153,223
5,475
69,266
2,038
1,915
19,274
20,197
33,199
194,430
5,700
64,204
73,476
35,873
126,679
470
144,764
7,316
119,535
269,262
6,901
646
122,142
58,935
27,670
27,553
2,520
468
3,493,716
High-end estimate
90,947
57,851
137,466
307,118
121,635
82,423
6,447
69,056
4,517
101,157
41,347
151,140
184,665
8,503
83,481
2,847
2,471
25,958
27,799
44,712
245,368
8,851
80,798
101,131
45,851
165,411
607
182,691
11,361
150,852
370,609
10,716
833
159,486
75,330
36,130
34,674
3,914
611
4,462,352
Tons of TSS discharged annually after reductions because of current state required construction site controls.
Page 10-28
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Section 11: Estimating Pollutant Load Reductions
Table 10-14a. Estimated Annual Option 1 Construction Site Eroded Sediment Captured
Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
1,767,117
80,598
109,990
161,319
127,996
17,077
52,316
4,632,051
4,000,634
19,899
200,843
114,259
85,730
188,687
1,250,645
161,764
75,314
415,185
56,685
213,939
91,446
1,450,393
113,786
52,734
51,288
48,538
30,783
112,891
66,943
206,057
2,321,918
52,876
163,024
233,354
503,829
1,031,548
6,465
2,092,920
66,824
1,675,837
Average estimate
2,389,031
127,795
173,941
255,786
230,497
23,992
73,787
6,261,977
5,408,576
28,746
270,670
153,999
108,105
237,931
1,690,729
255,819
105,826
585,444
79,649
288,321
123,243
1,960,759
143,480
94,965
64,682
76,961
43,250
152,071
105,858
277,564
3,139,047
95,209
219,732
369,043
699,126
1,454,625
9,086
2,829,360
120,325
2,265,563
High-end estimate
3,040,126
180,691
242,964
361,660
363,610
31,315
97,266
7,968,300
6,882,568
38,075
344,237
195,871
131,409
289,215
2,151,442
357,333
138,144
771,589
103,971
366,688
156,744
2,495,047
174,404
149,810
78,632
108,816
56,455
206,969
147,858
377,753
3,994,503
150,179
279,483
515,497
902,551
1,917,192
11,862
3,600,313
189,798
2,882,938
Page 10-29
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Section 11: Estimating Pollutant Load Reductions
Region
6
8
1
3
lOb
3
5
8
3
State
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
854,345
69,690
9,829
963,596
908,546
228,334
70,383
23,077
1,706
27,235,009
Average estimate
1,351,098
125,487
13,805
1,358,796
1,260,729
321,966
94,855
41,554
2,410
37,565,271
High-end estimate
1,887,255
197,942
18,015
1,790,883
1,627,570
424,331
120,639
65,548
3,182
48,588,644
Tons of TSS captured annually because of management technologies.
Table 10-14b. Estimated Annual Option 2 Construction Site Eroded Sediment Captured
Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
2,201,734
81,903
233,468
164,924
135,399
18,929
59,773
4,646,226
4,868,188
19,899
476,413
267,590
563,055
1,174,677
1,638,883
318,245
88,264
586,476
57,973
313,367
174,881
1,888,719
747,474
52,734
231,576
Average estimate
2,977,371
129,869
369,805
261,514
243,869
26,599
84,320
6,281,166
6,582,973
28,746
642,756
361,030
710,878
1,483,026
2,216,282
504,031
124,062
827,351
81,462
422,574
235,904
2,554,117
943,683
94,965
292,355
High-end estimate
3,789,625
183,628
517,137
369,772
384,748
34,723
111,169
7,992,745
8,378,653
38,075
818,170
459,566
864,992
1,804,489
2,820,953
704,782
161,988
1,090,815
106,341
537,690
300,245
3,250,937
1,148,236
149,810
355,718
Page 10-30
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Section 11: Estimating Pollutant Load Reductions
Region
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
3
State
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
48,538
32,298
146,548
68,481
307,652
2,896,661
64,598
397,979
454,639
572,575
1,516,913
7,143
2,290,318
87,109
2,155,815
1,612,148
69,690
12,178
1,380,144
990,892
334,676
133,951
23,077
2,231
36,617,027
Average estimate
76,961
45,384
197,489
108,297
414,665
3,917,064
116,380
536,986
720,062
794,675
2,140,118
10,040
3,096,574
156,961
2,915,312
2,553,152
125,487
17,111
1,947,091
1,375,181
472,144
180,686
41,554
3,156
50,443,239
High-end estimate
108,816
59,245
268,867
151,272
564,613
4,985,627
183,644
683,583
1,006,867
1,026,062
2,821,818
13,110
3,940,720
247,709
3,710,675
3,569,907
197,942
22,335
2,567,233
1,775,518
622,505
229,960
65,548
4,171
65,202,751
Tons of TSS captured annually due to management technologies.
Table 10-14c. Estimated Annual Option 3 Construction Site Eroded Sediment Captured
Region
4
9
6
9
8
1
3
4
4
lOa
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
2,561,438
96,884
278,158
194,747
183,780
22,930
87,115
6,745,657
5,765,027
32,068
Average estimate
3,464,301
153,673
440,694
308,902
331,255
32,231
122,943
9,123,137
7,797,013
46,354
High-end estimate
4,409,936
217,340
616,367
436,883
522,885
42,086
162,146
11,613,177
9,925,239
61,429
Page 10-31
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Section 11: Estimating Pollutant Load Reductions
Region
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
9
1
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
3
State
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
District of Columbia
National Total
Tons of total suspended solids (TSS) captured per year1
Low-end estimate
572,889
344,364
728,404
1,625,831
1,775,696
420,498
100,526
689,269
74,426
627,279
260,186
2,101,327
978,523
74,845
437,690
57,952
40,504
212,692
154,355
383,217
3,320,603
75,965
484,118
550,296
699,000
1,688,232
8,699
2,880,238
96,556
2,326,203
2,016,886
97,706
13,097
1,598,804
1,230,034
373,063
211,160
33,095
2,546
45,334,577
Average estimate
773,023
464,691
919,683
2,052,739
2,401,485
666,227
141,328
972,522
104,629
846,437
351,091
2,841,921
1,235,443
134,907
552,643
91,919
56,938
286,743
244,501
516,638
4,490,945
136,909
653,297
871,799
970,390
2,382,075
12,232
3,895,134
174,022
3,145,967
3,195,160
176,086
18,404
2,255,907
1,707,560
526,354
284,934
59,647
3,603
62,436,439
High-end estimate
984,093
591,600
1,119,112
2,497,826
3,056,886
931,824
184,564
1,282,386
136,632
1,077,576
446,966
3,617,575
1,503,303
212,952
672,495
130,000
74,351
390,509
341,920
703,595
5,716,699
216,096
831,733
1,219,275
1,253,203
3,141,122
15,976
4,958,012
274,678
4,004,513
4,468,600
277,926
24,024
2,974,765
2,205,173
694,041
362,740
94,147
4,764
80,701,136
Tons of TSS captured annually due to management technologies.
Page 10-32
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Section 11: Estimating Pollutant Load Reductions
Table 10-15 provides the reductions in eroded sediment discharged from the nation's
construction sites based on a comparison of baseline and option controls.
Table 10-15. Reductions in Estimated National Construction Site Discharged Material
from Baseline Discharge Levels (Million Tons of TSS per Year) for Regulatory Options
Option 1
Option 2
Option 3
Option 1
Option 2
Option 3
Low-end estimate
Average estimate
High-end estimate
Load reduction (million tons TSS)
0.25
9.63
18.35
0.34
13.21
25.21
0.43
17.04
32.54
Percent load reduction
1.2%
46.0%
87.7%
1.2%
46.0%
87.8%
1.2%
46.1%
87.9%
EPA's evaluation of Option 1 estimates that it would reduce baseline C&D TSS discharges by
approximately 1 percent. It should be noted that many of the states currently requiring 1,800
cf/acre basins either have relatively low levels of construction rates, and/or have conditions that
are less likely to produce erosion (low rainfall and low erosive soils).
Option 2 produces an approximately 46 percent reduction in TSS, relative to baseline loads. This
reduction occurs because ATS is estimated to be required on approximately 40 percent of
developed acres nationwide to meet the turbidity limit. In addition, under Option 2,
approximately 11 percent of developed acres are required to install larger sediment basins.
As expected, the C&D discharge loads for Option 3 are the lowest of the options considered.
Option 3 requires a turbidity limit for all sites larger than 10 acres, regardless of location or soil
nature. This is estimated to affect approximately 86 percent of developed acres nationwide.
Because ATS is assumed to remove 100 percent of TSS on the acres applied, the load values
shown in Table 10-13c are the baseline loads associated with all C&D sites smaller than 10 acres
in size. Option 3 is expected to reduce baseline construction site TSS loads by approximately 88
percent.
As described in Section 3.5.1, EPA used the River Reach File as the foundation for summarizing
land cover change in drainage area units (or watersheds). EPA allocated the expected TSS loads
under baseline conditions and under each regulatory option evaluated to individual RFls which
served as the basis for input to the U.S.Geological Survey SPARROW model to determine the
extent of potential water quality improvements attributable to each of the regulatory options
being considered by EPA for the proposed rule. Loads were allocated to RFls on the basis of the
amount of development occurring within each RF1, with consideration of RF1 percent clay
content and R-factors. Loads were distributed to a total of 43,885 RFls. The Environmental
Impact and Benefits Assessment for Proposed Effluent Guidelines and Standards for the
Page 10-33
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Section 11: Estimating Pollutant Load Reductions
Construction and Development Category (EPA-821-R-08-009 discusses the results of the
SPARROW modeling and the potential benefits of the regulatory options).
10.6. REFERENCES
Warner, R.C., P.J. Schwab and DJ. Marshall. 1999. SEDCAD 4 for Windows 95 & NT - Design
Manual and User's Guide. Civil Software Design. Ames, IA. August 1999.
CSQA 2003. (California Stormwater Quality Association). California Stormwater Best
Management Practices - Construction Handbook. California Stormwater Quality
Association, Menlo Park, CA.
Skaggs, T.H., L. M. Arya, P. J. Shouse, and B. P. Mohanty. 2001. Estimating Particle-Size
Distribution from Limited Soil Texture Data. Published in Soil Sci. Soc. Am. J. 65. Pp. 1038-
1044.
USD A 2005. Revised Universal Soil Loss Equation, Version 2 (RUSLE2). USD A Agricultural
Research Service Program Database.
Page 10-34
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Section 11: Non-Water Quality Environmental Impacts
11. NON-WATER QUALITY ENVIRONMENTAL IMPACTS
Sections 304(b) and 306(b) of the Clean Water Act require the U.S. Environmental Protection
Agency (EPA) to consider non-water quality environmental impacts (including energy
requirements) associated with effluent limitations guidelines and standards. In accordance with
these requirements, EPA has considered the potential impacts of the proposed regulation on
energy consumption, solid waste generation, and air emissions. The estimates of these impacts
for the construction and development (C&D) industry are summarized in Sections 11.1, 11.2,
and 11.3.
11.1. ENERGY REQUIREMENTS
EPA considered the additional energy requirements attributable to the regulatory options
(Section 11.1.1) and the production of treatment chemicals (Section 11.1.2), and compared the
option energy requirements with the energy requirements of the C&D industry (Section 11.1.3).
11.1.1. ENERGY REQUIREMENTS ATTRIBUTABLE TO THE REGULATORY
OPTIONS
EPA estimates that additional energy requirements attributable to the regulatory options being
considered are the result of the operation of pumps and generators (diesel) that would be needed
as part of the regulatory options that require use of advanced treatment technologies (Options 2
and 3). Table 11-1 presents estimates of energy usage by regulatory option considered under this
proposal.
Table 11-1. Estimated Energy Consumption by Regulatory Option
Option
2
3
Incremental energy consumption required
22 million gallons of diesel fuel
45 million gallons of diesel fuel
Under Option 1, no significant additional energy requirements would be expected. Option 1
involves installing larger sediment basins and installing a range of best management practices.
These requirements are not expected to result in a significant increase in energy requirements.
Additional excavation would be required in some states to install larger basins; however, EPA
has not quantified energy requirements for construction equipment because equipment used
would be highly site-specific. As described further in Sections 7.1.5.3.4 and 7.1.5.3.5, sediment
traps and basins are designed such that all stormwater runoff flows through the basins by gravity.
Because gravity flow is assumed, no additional energy would be required for sediment basin
operations.
Options 2 and 3 involve the use of advanced treatment systems, including coagulation and
flocculation followed by filtration, which require additional energy usage. EPA assumed that
diesel powered generators and pumps would be used to operate active treatment systems (ATS).
For a 500-gallon-per-minute (GPM) system, fuel consumption is approximately 10 gallons per
hour (Rain for Rent 2008). EPA estimates that under Option 2, total stormwater treatment
Page 11-1
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Section 11: Non-Water Quality Environmental Impacts
volumes would be about 65.6 billion gallons per year, while under Option 3, the total treatment
volumes would be approximately 135.5 billion gallons per year. At 500 GPM, total system run
time (not counting recirculation) for Option 2 would be approximately 2.2 million hours, while
under Option 3, the total system run time would be approximately 4.5 million hours. Therefore,
diesel fuel consumption under Option 2 would be approximately 22 million gallons, while under
Option 3, consumption would be approximately 45 million gallons. As with Option 1, some
additional excavation would be required under Option 2 and 3 to install larger sediment basins
and storage for ATS; however, EPA has not quantified energy requirements because equipment
usage would be highly site-specific.
11.1.2. TREATMENT CHEMICAL PRODUCTION
EPA considered the availability and additional energy consumption from treatment chemicals.
Section 11.1.2.1 describes chitosan, the basis for EPA's Best Available Technology
Economically Achievable (BAT) option, and Section 11.1.2.2 describes polyacrylamides.
11.1.2.1. Chitosan
Chitosan is derived from chitin, the major component of crustacean shells and is a cationic
polyelecrolyte. Chitosan (poly-D-glucosamine) is one of the most common polymers found in
nature (USEPA 2003). Chitin is the second most abundant natural fiber after cellulose and is
similar to cellulose in many respects (Hennen 1996). Global Industry Analysts, Inc., estimates
that the global chitin market will exceed 51.4 thousand metric tons (113 million pounds) by 2012
(Global Industry Analysts, Inc. 2008). The United States could produce approximately 30
percent of the worldwide shellfish harvest each year (Hennen 1996). Therefore, EPA estimates
that the U.S. chitin market could approach 34 million pounds by 2012.
Minton (2006) reported an average chitosan acetate dose rate of 2 milligrams per liter (mg/L).
Minton (2006) noted that the Washington State Department of Ecology specifies a maximum
dosage of 1 mg/L, but that variances are granted for turbidities greater than 600 nephelometric
turbidity units (NTU). Minton (2006) reported chitosan acetate dosages as high as 3 mg/L. Table
11-2 presents the amount of chitosan acetate required from applying a 2 mg/L chitosan acetate
dosage to the stormwater volumes requiring treatment from Section 11.1.1.
Table 11-2. Maximum Chitosan Acetate Required under EPA Options
Option
2
3
Stormwater treated
(billions of gallons)
65.6
135.5
Chitosan acetate required
(millions of pounds)
1.1
2.3
The amount of chitosan acetate in Table 11-2 represents a fraction of the total chitin market. In
addition, EPA expects the amount of chitosan would be less than the amount presented in Table
11-2 because many construction sites would use other treatment chemical alternatives, including
polyacrylamide, described in Section 11.1.2.2.
Page 11-2
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Section 11: Non-Water Quality Environmental Impacts
Because chitosan is manufactured from crustacean shells, additional energy consumption from
chitosan production and usage is expected to be minimal.
11.1.2.2. Polyacrylamide (PAM)
Polyacrylamides (PAM) are a broad class of compounds that include cationic (positively
charged) and anionic (negatively charged) PAM. PAM are water soluble over a wide pH range
and exhibit a high affinity for suspended sediment. PAM are derived from acrylamide, of which
94 percent is used as PAM (ICIS Chemical Business 2008). U.S. demand for PAM is presented
in Table 11-3.
Table 11-3. US Acrylamide / PAM Demand*
Year
2007
20 11 (projected)
Acrylamide demand
(million Ibs)
253
290
PAM demand
(million Ibs)
238
273
* U.S. demand equals production plus imports less exports
Source: ICIS Chemical Business 2008
Polymers such as PAM are produced from petroleum, so additional PAM consumption to treat
construction site stormwater runoff would result in increased petroleum consumption. However,
consumption on construction sites is not expected to significantly increase demand for
acrylamide.
11.1.3. COMPARISON OF OPTION ENERGY REQUIREMENTS TO
CONSTRUCTION INDUSTRY
Table 11-4 presents an estimate for construction industry fuel consumption based on the 2002
census.
Table 11-4. 2002 Energy Use in NAICS Category 23
Census Category
Gasoline and diesel fuel
NAICS category 23
$10,953,670,000a
2002 unit cost
$1.32/gallonb
NAICS category 23 Energy Use
(millions of gallons)
8,300
a U.S. Census Bureau 2002.
b Energy Information Administration 2002.
Table 11-5 presents estimates of energy usage by regulatory option considered under this
proposal, compared to the total annual diesel and gasoline consumption in NAICS Category 23
(Construction).
Page 11-3
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Section 11: Non-Water Quality Environmental Impacts
Table 11-5. Estimated Incremental Energy Usage by Regulatory Option
Option
Option 2
Option 3
Option diesel consumption
(millions of gallons)
22
45
Fraction of NAICS category 23 Energy
(gallons)
0.003
0.005
Options 2 and 3 correspond to approximately 0.3 and 0.5 percent of the NAICS 23 construction
category fuel consumption, respectively. EPA does not expect any adverse impacts to occur as a
result of the small incremental energy requirements for the proposed regulation.
11.2. AIR EMISSIONS IMPACTS
The Agency believes that none of the regulatory options for this rule would generate significant
air emissions.
According to the Construction Industry Compliance Assistance Compliance Summary Tool
(http://www.cicacenter.org/cs.cfm) there are no federal Clean Air Act (CAA) requirements that
apply to the C&D industry. CAA requirements are implemented primarily by states through their
State Implementation Plans (SIPs). Following are examples of construction-related emissions
that might require a state permit under an SIP:
Nitrogen oxides (NOx) and fine particulates from construction equipment diesel
engines
Dust from vehicle traffic, from loading and unloading of construction materials at
transfer points, and from conveyor systems transporting building materials
Visible stack emissions from off-road equipment
Volatile organic compounds (VOCs) from paint and cleaning solvents
To the extent that usage of heavy construction equipments would be expected to increase from
installing larger sediment basins, or portable generators or diesel powered pumps are used to
power ATS, there would be an increase in fine particulate matter, VOCs, and NOx, and other
pollutants, as well as increased CO2 emissions, as estimated below.
EPA estimated air emissions on the basis of emission factors from diesel generators, the primary
source of construction site air emissions. A 135-kilowatt generator (210 horsepower [hp])
generator would consume approximately 10 gallons of diesel per hour (Diesel Supply and
Service, no date). EPA multiplied the total system run time presented in Section 11.1 by the
emission factors from a 210-hp diesel generator (interpolated from 2008 generator set emission
factors (Ibs/hr) from the California South Coast Air Quality Management District (SC AQMD
2008)). Table 11-6 presents the estimated incremental air emissions by regulatory option.
Page 11-4
-------
Section 11: Non-Water Quality Environmental Impacts
Table 11-6. Estimated Incremental Air Emissions by Regulatory Option (Pounds/Year)
Option
Option 2
Option 3
Reactive
organic
gases
(ROG)
393,303
839,558
Carbon
monoxide
(CO)
1,408,976
2,549,305
Nitrogen
oxides
(NOx)
4,087,478
10,298,884
Sulfuric
oxides
(SOx)
4,169
10,800
Particulate
matter
(PM)
156,025
314,837
Carbon
dioxide
(CO2)
370,542,245
959,885,201
Methane
(CH4)
35,487
75,752
Because construction air emissions are primarily from fuel combustion, EPA estimates that the
increase in air emissions relative to the construction industry air emissions would be similar to
the estimates for the fraction of construction industry fuel consumption (i.e., Options 2 and 3
correspond to approximately 0.3 and 0.5 percent of the NAICS 23 construction category).
11.3. SOLID WASTE GENERATION
Solid waste generated at C&D sites include treatment residuals generated as part of coagulation
and flocculation from active treatment systems. These can include spent cartridge or bag filters,
or filter media (usually sand). EPA did not quantify solid waste generated from spent cartridge or
bag filters, because it is not clear whether permittees would require cartridge or bag filters as a
final finishing step after ATS. Sediment removed from sediment basins and ATS, including
sediment containing polymers, can generally be used as fill material on the construction site.
Therefore, EPA expects that solid waste generation would be minimal.
11.4. REFERENCES
Diesel Service and Supply, Inc. No date. Approximate Fuel Consumption Chart.
. Accessed November 14, 2008. DCN 43090.
Energy Information Administration. 2002. Average 2002 dieselfuel cost. U.S. On-Highway
Diesel Fuel Prices, . Release Date April
21,2008. DCN 43088.
Global Industry Analysts, Inc. 2008. PRWeb Press Release Newswire. Global ChitinMarket to
Exceed 51.4 Thousand Metric Tons by 2012. DCN 43084.
Hennen, WJ. 1996. Chitosan. Woodland Publishing, Utah. DCN 43085.
ICIS Chemical Business. 2008. Chemical profile: acrylamide.
. Accessed November 6,
2008. DCN 43086
Minton, G.R. 2006. Technical Engineering Evaluation Report (TEER) for the Chitosan-
Enhanced Sand Filtration Technology for Flow-through Operations. Developed by Natural
Site Solutions, LLC, prepared by Resource Planning Associates. DCN 43002.
SC AQMB (South Coast Air Quality Management District). 2008. Off-road Mobile Source
Emission Factors. California South Coast Air Quality Management District, CA.
Page 11-5
-------
Section 11: Non-Water Quality Environmental Impacts
Accessed May 22, 2008. DCN
43089.
Rain for Rent. 2008. Chitosan-Enhanced Sand Filtration Example Quote #1 and #2 (March
2008). DCN 43007.
U.S. Census Bureau. 2002. Economic Census Construction Industry General Summary 2002.
Issued October 2005. U.S. Census Bureau, Washington, DC. DCN 43079.
USEPA (U.S. Environmental Protection Agency). 2003. Chitosan: Poly-D-glucosamine
(128930) Fact Sheet.
.
Accessed November 14, 2008. DCN 43087.
Page 11-6
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Appendix A
Summary of State Construction and Development Requirements
-------
-------
APPENDIX A: SUMMARY OF STATE CONSTRUCTION AND DEVELOPMENT REQUIREMENTS
State requirements SUMMARY
State
Alabama
Alaska
Arizona
Arkansas
Sediment basin
storage volume
(ft3/acre drained)
1,800 (EPA 2007)
3,600 (2004 TDD
Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
(1) 8-hour detention time for sites > 5 acres
(EPA 2007) (2) 67 cy/acre (1,809 ft3) -
(Alabama Handbook for Erosion Control,
Sediment Control and Stormwater
Management on Construction Sites and Urban
Areas June 2003, Revised 1-06)
The EPA 2007 literature referenced the CGP
and noted a sediment basin volume of 1,800
ft3/acre plus 1.5 ft for sediment accumulation
- generally designed to remove medium silt
(62 microns) particles.
Sizing based on a 2-year, 24-hour event (EPA
2007)
Temporary or permanent sediment basins
shall be based on either the smaller of 3,600
ft3/acre, or a size based on the runoff volume
of a 10-year, 24-hour storm event (EPA
2007).
Sediment basin notes/references
The 2004 TDD Section 7 notes: a sediment basin
storage volume of 3,600 ft3/acre drained, and
sediment basin requirements for drainage areas >
10 acres.
The 2004 TDD Section 7 notes sediment basin
requirements for drainage areas > 10 acres. 2002
water quality standards specify that all stormwater
treatment devices shall be designed based on the
2-year, 6-hour rain event (assume runoff), and the
Best Management Practice (BMP) must also be
capable of removing particles greater than 20-
microns during such an event.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2004 TDD Section 7 notes sediment basin
requirements for drainage areas > 10 acres.
Numeric standard
Statewide standard varies with
background, < 50 Nephelometric
Turbidity Units (NTUs) above
background. The EPA literature noted
"None." The 2002 TDD Appendix A
notes: Turbidity <50 NTU. Turbidity
limits as set forth by the Alabama
Department of Environmental
Management are 50 NTUs above
background for any Alabama waterbody
with a Fish and Wildlife classification
(Alabama Department of Environmental
Management 2001). PG Environmental
(PG) determined that the Alabama
Department of Environmental
Management- Water Division Water
Quality Program (2006) states in its
specific water quality criteria Section
335-6- 10-. 09 that there shall be no
turbidity other than natural origin and
that in no case shall turbidity exceed 50
NTUs above background.
The 2002 TDD Appendix A notes total
suspended solids (TSS) > 20 microns.
The EPA 2007 literature notes "None."
None (EPA 2007)
PG estimated post-construction standard
only. A goal of 80 percent removal of
TSS from these flows (e.g., stormwater
detention structures-including wet
ponds), which exceed predevelopment
levels should be used in designing and
installing, where practicable (EPA 2007;
state literature).
Soil stabilization
13 days (EPA 2007)
14 days. Reference to the
CGP (EPA 2007)
14 days (EPA 2007)
14 days (EPA 2007)
-------
>
State requirements SUMMARY
State
California
Colorado
Connecticut
Sediment basin
storage volume
(ft3/acre drained)
3,600 (EPA 2007;
2004 TDD Section 7)
1,800 general/3,600
transportation
3,600 (EPA 2007)
Sediment basin (design parameters)
Other design standards include a settling
velocity approach, where the precipitation
intensity for a 10-year, 6-hour rain event is
used (EPA 2007).
N/A
The EPA 2007 literature notes basin sizing of
3,600 ftVacre.
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
requirements for drainage areas > 10 acres.
The 2004 TDD Section 7 notes sediment basin
requirements of 1,800 ft3/acre drained. The EPA
2007 literature notes sediment basin sizing of
3,600 ftVacre for Colorado Department of
Transportation (CDOT).
The 2004 TDD Section 7 notes a sediment basin
storage volume of 1,800 ftVacre drained. The
EPA, 2007 literature noted that sediment basins
required for sites greater than 2 acres.
Numeric standard
California's draft CGP includes
turbidity effluent levels of 1,000 NTU.
If Active Treatment Systems are used,
the daily flow- weighted average is 10
NTU and the maximum for any single
sample is 20 NTU.
None (EPA 2007)
PG estimated no numeric standard for
active construction sites based on
review of state literature. The EPA 2007
literature notes 80% TSS. The 2004
Connecticut Stormwater Quality
Manual, Chapter 6 states, The State of
Connecticut has adopted the 80 percent
TSS removal goal based on EPA
guidance and its widespread use as a
target water quality performance
standard. The 2004 Connecticut
Construction General Permit for
Stormwater discharges noted that the 80
percent TSS removal was for post-
construction. The 2002 TDD Appendix
A notes an 80 percent TSS reduction.
Soil stabilization
Not specified (EPA 2007
and 2002 TDD Appendix
A). 2004 TDD confirmed
that CA has no
stabilization standard
within 14 days.
14 days. PERMIT NO.
COR10*##F
(http ://www.epa. gov/regio
n8/water/stormwater/dow
nloads/Cof con.pdf states
14 days. There is no
stabilization standard
within 14 days per 2004
TDD. Douglas County
requires that disturbed
areas be drill seeded and
crimp mulched, or
permanently landscaped,
within 30 days from the
start of land disturbance
activities or within 7 days
of the substantial
completion of grading and
topsoiling operations,
whichever duration is
shorter (EPA 2007).
3 days. Where
construction activities
have permanently ceased
or have temporarily been
suspended for more than 7
days, or when final grades
are reached in any portion
of the site stabilization
practices shall be
implemented within 3
days. Areas that will
remain disturbed but
inactive for at least 30
days shall receive
temporary seeding. Areas
that will remain disturbed
beyond the planting
-------
State requirements SUMMARY
State
Delaware
Florida
Florida, DEP,
Northern
District (only
applies in NW
Florida)
Florida, South
Florida Water
Management
District
(General,
Standard
General,
Noticed
General and
Individual
Permits)
Florida,
Southwest
Florida Water
Management
District
Florida, St.
Johns River
Water
Management
District
Sediment basin
storage volume
(ft3/acre drained)
3,600 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
N/A
N/A
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
Numeric standard
PG estimated no numeric standard. The
EPA 2007 literature states "None." The
2002 TDD Appendix A notes an 80
percent TSS reduction; however, PG
determined from state literature that this
was a post-construction standard.
PG estimated no statewide numeric
standard. The EPA 2007 literature states
"None." The 2002 TDD Appendix A
notes some standards for specific
regions, but no statewide requirements.
The 2002 TDD Appendix A notes an 80
percent TSS reduction.
The 2002 TDD Appendix A notes a
turbidity less than 29 NTU.
Soil stabilization
season, shall receive long-
term, nonvegetative
stabilization sufficient to
protect the site through the
winter (EPA 2007).
14 days (EPA 2007)
7 days (EPA 2007)
-------
>
State requirements SUMMARY
State
Florida,
Suwannee
River Water
Management
District
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Sediment basin
storage volume
(ft3/acre drained)
1,800 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007)
3,600 (EPA 2007;
2004 TDD Section 7)
3,600 (2002 TDD
Appendix A)
1,800 (2004 TDD
Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
Basin sizing for a 2-year, 24-hour storm event
for drainage areas > 10 acres (EPA 2007).
Basin sizing for a 2-year, 24-hour storm event
for drainage areas > 10 acres (EPA 2007).
No sizing criteria in permit (EPA 2007). The
2002 TDD Appendix A notes 3,600 ftVacre.
No sizing criteria in permit (EPA 2007). The
2004 TDD Section 7 states that for a state
program that did not note a sediment basin
size, EPA assumed based on best professional
judgement (BPJ) that the baseline size was
1,800 fYVacre.
The 2002 permit states that a sediment basin
shall be installed for drainage area more than
10 acres disturbed. (Flows from upland areas
that are undisturbed may be diverted around
Sediment basin notes/references
The 2002 TDD Appendix A notes water runoff
from 25-year, 24-hour storm event shall be treated
for water quality management. PG assumed the
25-year storm event is for the emergency spillway
per the 2004 TDD ("Typical return periods vary
between 25 and 100 years, with 25 years
recommended by the USDOT").
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2002 Illinois Urban Manual states that the
basin requirements shall be based on a 2-year, 24-
hour storm or 134 cubic yards/acre (i.e., 3,600
ft3/acre) whichever is greater (EPA 2007).
General NPDES Permit No. ILR10 5/30/2003
notes that "The management practices, controls
and other provisions contained in the stormwater
pollution prevention plan must be at least as
protective as the requirements contained in
Illinois Environmental Protection Agency's
Illinois Urban Manual, 2002."
Sediment basin requirements exist for some areas
in State (EPA 2007).
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes: The 2006
Iowa Construction Site Erosion Control Manual
Numeric standard
The 2002 TDD Appendix A notes an 80
percent TSS reduction.
Statewide standard varies with
background. Cannot increase turbidity
by more than 25 NTU in warm waters
and 10 NTU in cold water trout streams.
Allowable turbidity in effluent varies
based on site size and receiving stream
drainage area (EPA 2007). The 2002
TDD Appendix A notes turbidity < 10
to 25 NTUs.
No numeric requirements for
stormwater pollutant removal have been
established at the state level, but
regional and municipal regulations are
in place (EPA 2007).
None. None listed in EPA 2007 or 2002
TDD Appendix A.
None (EPA 2007)
Only in certain parts of Indiana (e.g., 80
percent of TSS removal in Marion
County). (EPA 2007).
PG estimated no numeric standard. The
EPA 2007 literature states "None." The
2002 TDD Appendix A notes an 80
percent TSS reduction; however, PG
Soil stabilization
14 days (EPA 2007)
30 days (EPA 2007)
14 days (EPA 2007)
14 days (unless covered
with snow or construction
will resume within 2 1
days) (EPA 2007).
15 days (EPA 2007)
14 days (unless covered
with snow or construction
will resume within 2 1
days) (EPA 2007).
-------
State requirementsSUMMARY
State
Sediment basin
storage volume
(ft3/acre drained)
Sediment basin (design parameters)
Sediment basinnotes/references
Numeric standard
Soil stabilization
the basin) (EPA 2007).
states that the size of the sediment basin, is as
measured from the bottom of the basin to the
principal spillway and should provide at least
3,600 ft3 of storage per acre of drainage. This
provides storage equal to 1 inch of runoff per
acre. Likewise, 1,800 ft3 amounts to 1/2 inch of
sediment storage per acre. The basin should be
cleaned when the volume of sediment reaches 900
ft3/acre. At this time, the cleanout shall be
performed to restore the original design capacity
of the basin. At no time should the sediment level
be permitted to build higher than 1 foot below the
principal outlet.
could not confirm that this standard was
for active construction sites.
>
Kansas
3,600 (EPA 2007;
2004 TDD Section 7)
Kansas 1/30/07 CGP Definitions and
Acronyms pages states, "Sediment Basin
Design Criteria requires sedimentation
structures that receive runoff from 10 acres or
more of disturbed area to provide at least
3,600 ft3 of storage per acre of area drained
into the sediment basin. KDHE may approve
alternate storage volumes if significant
portions of undisturbed area drain to the
sediment basin."
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes that the 2007
permit requires a storage capacity of 3,600 ft3/acre
and the Sediment Basin Design Criteria in the
permit states, "rational method or other equivalent
runoff calculations based on storage of a 2.6 inch
rainfall event with a minimum runoff coefficient
of 0.77 for disturbed acreage and appropriate
runoff coefficients for undisturbed acreage must
be provided to determine the revised storage
volume requirement." The field guide for
Missouri and Kansas says that for drainage areas
of 20 acres or less, the sediment storage shall be
1,800 ftVacre with a detention time of at least 24
hours (EPA 2007).
None (EPA 2007)
Not specified; however, it
states, "time should be
minimized" (EPA 2007).
Kentucky
3,600 (EPA 2007;
2004 TDD Section 7)
The 2002 permit requires a basin sizing of
3,600 ft3/acre for drainage locations >10 acres
(EPA 2007). The EPA 2007 literature notes in
the 2007 Draft Kentucky BMP Manual
requires basin sizing of 3,600 ft3/acre, not to
exceed 10 acre-feet for areas 5 to 120 acres
with the goal to provide a detention time of 24
to 48 hours and 80 percent TSS reduction for
the 10-year, 24-hour storm.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
PG noted that there was only numeric
standard requirements for Jefferson
County and no statewide standard. 80%
TSS removal only for Jefferson (EPA
2007). The 2002 Appendix A notes a
goal of 80 percent TSS reduction
(compared to pre-construction levels). A
goal of 80 percent removal of TSS from
flows that exceed predevelopment levels
(2002 General KPDES Permit for
Stormwater Point Source Discharges,
Construction Activity, page IV-2).
14 days (unless covered
with snow or construction
will resume within 21
days) (EPA 2007).
Louisiana
3,600 (EPA 2007;
2004 TDD Section 7)
For 10 or more disturbed acres, either the
smaller of 3,600 ft3/acre or a 2-year, 24-hour
storm. This does not apply to flows from off-
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. For drainage locations serving less than 10
Not directly applicable. There are
standards for permitted support
activities related to a construction site
14 days (EPA 2007)
-------
>
State requirements SUMMARY
State
Maine
Maryland
Massachusetts
Michigan
Sediment basin
storage volume
(ft3/acre drained)
3,600 (2004 TDD
Section 7)
3,600 (EPA 2007)
3,600 (2004 TDD
Section 7)
3,600 (2004 TDD
Section 7; 2002 TDD
Appendix A)
Sediment basin (design parameters)
site areas and flows from on-site areas that are
either undisturbed of have undergone final
stabilization where such flows are diverted
around the sediment basin (EPA 2007).
No sizing criteria in permit (EPA 2007).
N/A
Basin size based on the runoff volume of a 2-
year, 24-hour storm event (2002 TDD
Appendix A).
N/A
Sediment basin notes/references
acres, smaller sediment basins and/or sediment
traps should be used. At a minimum, silt fences,
vegetative buffer strips, or equivalent sediment
controls are required for all downslope boundaries
of the construction area unless a sediment basin
providing storage for a calculated volume of
runoff from a 2-year, 24-hour storm or 3,600 ft3 of
storage per acre drained is provided (EPA 2007).
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature states in the 2003
Erosion and Sediment Control BMPs Manual that
the capacity of the sediment basin shall be equal
to the stormwater volume to be detained plus the
volume of sediment expected to be trapped.
Periodic removal of sediment will be necessary to
maintain basin's capacity. Temporary basins
having drainage areas of 5 acres or less and a total
embankment height of 5 feet or less may be
designed with less conservative criteria. Any
excavated pond with a drainage area in excess of
5 acres, or spring flow in excess of 100 gallons
per minute must be designed in accordance with
embankment pond criteria. Excavated ponds must
be designed to be drained within a 10-day period.
EPA 2007 (minimum of 3,600 ft3/acre).
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. In the EPA 2007 literature, it is noted that
EPA issues permit.
The 2002 TDD Appendix A notes sites > 10 acres
require an on-site temporary sediment basin. The
2004 TDD Section 7 also notes sediment basin
Numeric standard
(cement and concrete facilities, hot mix
asphalt/asphaltic concrete facilities,
stockpiles of sand and gravel, and non-
process area stormwater from cement,
concrete, and asphalt facilities). They
establish monthly monitoring
requirements and discharge limitations
for flow (parameters - TSS, TOC, Oil &
Grease, and allowable ranges of pH)
(EPA 2007).
None (EPA 2007). The 2002 TDD
Appendix A states: 40 to 80 percent
TSS reduction. PG could not verify
2002 TDD Appendix A, and assumed
no numeric standard.
PG estimated no numeric standard.
None (EPA 2007). The 2002 TDD
Appendix A states an 80 percent TSS
reduction based on the average annual
TSS loading from all storm events less
than or equal to the 2-year/24-hour
storm; however, PG could not confirm
for active construction sites.
PG estimated no numeric standard.
None (EPA 2007). The 2002 TDD
Appendix A notes an 80 percent TSS
reduction; however, PG could not
confirm for active construction sites.
None (EPA 2007).
Soil stabilization
14 days. Operators must
stabilize with mulch, or
other non-erodible cover,
any exposed soils that will
not be worked for more
than 7 days. Must stabilize
areas within 75 feet of a
wetland or waterbody
within 48 hours of the
initial disturbance of the
soil or before any storm
event, whichever comes
first (EPA 2007).
14 days (7 days for steep
slopes) (EPA 2007).
14 days. In the EPA 2007
literature it is noted as 14
days with a CGP
reference.
1 5 calendar days after
final grading or the final
earth change has been
-------
State requirementsSUMMARY
State
Sediment basin
storage volume
(ft3/acre drained)
Sediment basin (design parameters)
Sediment basinnotes/references
Numeric standard
Soil stabilization
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes that the 1998
Guidebook for Best Management Practices for
Michigan Watersheds provides sediment basin
design recommendations (see longer write-up for
details) (EPA 2007). The 1998 Guidebook for
Best Management Practices for Michigan
Watersheds provides sediment basin design
recommendations. A straightforward method
requires a storage volume that is equal to 1/2 inch
of runoff from the contributing watershed. (For
residential areas, 1/2 inch of runoff would be
about a 1-year rainfall event in Michigan). For the
high percentage of particulate pollutant removal,
the detention basin should be designed so that it
will take at least 24 hours to drain the entire
volume stored. (For more information, see chapter
3 of the guidebook).
completed (EPA 2007).
>
Minnesota
3,600 (EPA 2007;
2004 TDD Section 7)
For 10 or more disturbed acres; (1) The basins
must provide storage below the outlet pipe for
a calculated volume of runoff from a 2-year,
24-hour storm from each acre drained to the
basin, except that in no case shall the basin
provide less than 1,800 ft3 of storage below
the outlet pipe from each acre drained to the
basin, (2) Where no such calculation has been
performed, a temporary (or permanent)
sediment basin providing 3,600 ft3 of storage
below the outlet pipe per acre drained to the
basin shall be provided where attainable until
final stabilization of the site (EPA 2007).
The 2004 TDD Section 7 also noted sediment
basin drainage requirements for drainage areas >
10 acres.
None; however, where an alternative,
innovative treatment system is proposed
and demonstrated by calculation, design
or other independent methods to achieve
80 percent TSS removal a 2-year
monitoring plan to sample runoff from
the proposed method must be submitted
(EPA 2007).
Steeper than 3:1, 7 days,
10:1 to 3:1, 14 days,
flatter than 10:1, 21 days
(EPA 2007)
Mississippi
3,600 (EPA 2007;
2004 TDD Section 7)
The Planning and Design Manual states that
the maximum allowable drainage area into the
basin shall be 25 acres. The design capacity of
the basin must be at least 67 yd3/acre (1809
ft3/acre). The capacity of the basin may be
estimated by 40% x Height x Surface Area.
The basin spillway shall be designed to
handle peak flow from a 10-year, 24-hour
storm event. If a principal spillway is used in
conjunction with an emergency spillway, the
principal spillway shall have a minimum
capacity of 0.2 cfs per acre of drainage area
when the water surface is at the crest of the
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
None (EPA 2007).
7 days. Within 7 days
when a disturbed area will
be left undisturbed for 30
days or more (EPA 2007).
-------
State requirementsSUMMARY
State
Sediment basin
storage volume
(ft3/acre drained)
Sediment basin (design parameters)
Sediment basinnotes/references
Numeric standard
Soil stabilization
emergency spillway. The embankment of the
sediment basin shall be temporarily seeded
within 15 days after its completion. The basin
should be designed according the following
data sheet (see more detailed summaries in
the manual) (EPA 2007).
Missouri
3,600 (EPA 2007)
>
oo
The 2007 permit states that basins are needed
for 10 acres or more, with a basin sizing at
least 3,600 ft3/acre. In valuable water resource
areas, the sediment basin needs to contain 1/2
inch of sediment from the drainage and
withstand the 2-year, 24-hour storm (EPA
2007). PG noted that the 2007 permit 2-year,
24-hour storm event was not a statewide
requirement (applies to valuable water
resource areas).
The 2004 TDD Section 7 notes a sediment basin
storage volume of 1,800 ftVacre drained. The
EPA 2007 literature notes that in the 1995 Erosion
and Sediment Manual the contributing area is
recommended to be 20 acres or less and sized to
store a minimum of 1,800 ft3 per disturbed acre
with a detention of at least 24 hours. The site
should be vegetated and stabilized immediately
after construction.
The 2002 TDD Appendix A notes that
settleable solids less than 2.5 ml/L per
hour for normal land disturbance, and
0.5 ml/L per hour for land disturbance
within sensitive areas. The EPA 2007
literature notes that per the Missouri
State Operating Permit General Permit
MO-R109000 3/8/2002: Construction
site discharges shall not violate Missouri
Code of State Regulations General
Water Quality Standards 10 CSR 20
7.031(3) or exceed a maximum
settleable solids concentration of 2.5
ml/L per hour for each stormwater
outfall. If the disturbed area is near a
Valuable Resources Water settleable
solids may not exceed 0.5 ml/L per
hour.
14 days; however, if the
slope of the area is greater
than 3:1 (3 feet horizontal
to 1 foot vertical) or if the
slope is greater than 3
percent and greater than
150 feet in length, then
interim stabilization
within 7 days of ceasing
operations on that part of
the site is required (EPA
2007).
Montana
1,800 (2004 TDD
Section 7)
No sizing criteria in permit (EPA 2007). The
2004 TDD Section 7 states that for a state
program that did not note a sediment basin
size, EPA assumed based on BPJ that the
baseline size was 1,800 ft3/acre. The 2002
TDD Appendix A notes a basin size based on
the runoff volume of a 2-year, 24-hour storm
event. PG could not verify the 2-year, 24-hour
storm event.
In the EPA literature, it notes in the Erosion and
Sediment Control Manual stating that desilting
basins are appropriate for areas of disturbed soil
between 5 acres and 10 acres in size. Desilting
basins shall be designed to have a capacity
equivalent to 100 m3 (1500 ft3) of storage (as
measured from the top of the basin to the principal
outlet,) per hectare (acre) of contributory area.
This design is less than that required to capture
0.01 mm (0.0004 in) particle size, but larger than
that required to capture particles 0.02 mm (0.0008
in) or larger. The depth must be no less than 1 m
(3 ft) nor greater than 1.5 m (5 ft). Basins shall be
designed to drain within 72 hours following storm
events.
The EPA 2007 literature notes that
BMPs must minimize or prevent
"significant sediment" (as defined in
Part VI of the General Permit p. 28)
from leaving the construction site.
Significant sediment means sediment,
solids, or other wastes discharged from
construction site, or a facility or activity
regulated under the General Permit
which exceeds 1.0 cubic foot in volume
in any area of 100 square feet that may
enter state surface water or a drainage
that leads directly to state surface water.
Not specified (EPA 2007).
2002 TDD Appendix A
confirmed no stabilization
within 14 days.
Nebraska
1,800 (2004 TDD
Section 7)
No sizing criteria in permit (EPA 2007). The
EPA 2007 literature also noted that sediment
basins required for 5 acres or more in size.
Where slopes are equal to or steeper than 3:1,
sediment basins may be required for smaller
None (EPA 2007).
14 days (Permit
NER110000)
-------
>
State requirements SUMMARY
State
Nevada
New
Hampshire
New Jersey
New Mexico
Sediment basin
storage volume
(ft3/acre drained)
3,600 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
1,800 (2004 TDD
Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
drainage areas. The 2004 TDD Section 7
states that for a state program that did not note
a sediment basin size, EPA assumed based on
BPJ that the baseline size was 1,800 ftVacre.
The EPA 2007 literature notes in the 2002
permit states that basin requirements for
drainage areas > 10 acres shall provided
storage of 3,600 ft3/acre or for a 2-year, 24-
hour storm event for each disturbed acre. For
a drainage location that serves 10 or more
acres disturbed at one time and where a
temporary sediment basin or equivalent
controls is not attainable, smaller sediment
basins and/or sediment traps should be used.
The EPA 2007 literature references the CGP
which specifies 3,600 ft3/acre or 2-year, 24-
hour runoff event.
The 2004 TDD Section 7 states that for a state
program that did not note a sediment basin
size, EPA assumed based on BPJ that the
baseline size was 1,800 ftVacre.
EPA Region 6 issues permit the 2003
general permit states that for 10 or more
disturbed acres at one time, a temporary (or
permanent) sediment basin providing at least
3,600 ft3/acre drained shall be provided until
final stabilization of the site. For drainage
locations which serve 10 or more disturbed
acres at one time and where a temporary
sediment basin or equivalent controls is not
attainable, smaller sediment basins and/or
sediment traps should be used. For drainage
locations serving less than 10 acres, smaller
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes to see design
specifications from the Department of
Conservation and Natural Resources (DCNR) and
1994 BMP manual.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes that EPA's
CGP applies, and to see the design specifications
from the 1992 Erosion and Sediment Control
Handbook.
New Jersey Erosion and Sediment Control and
Stormwater Management Requirements state that
Sediment Control Tanks shall be sized
accordingly: 1 ft3 of storage for each gallon per
minute of pump discharge capacity. Tanks may be
connected in series to increase effectiveness (EPA
2007).
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes that EPA
Region 6 issues permit.
Numeric standard
None (EPA 2007).
PG estimated no numeric standard. The
standard referenced is not relevant to
stormwater, only for excavation
dewatering. The EPA 2007 literature
states, must treat any uncontaminated
excavation dewatering discharges to
remove TSS and turbidity. TSS must
meet monthly average and maximum
daily TSS limitations of 50 mg/L and
100 mg/L, respectively.
None, standards are for post-
construction (EPA 2007).
None (EPA 2007).
Soil stabilization
14 days (EPA 2007).
14 days (EPA 2007).
Not specified (EPA 2007).
2002 TDD Appendix A
confirmed no stabilization
within 14 days.
14 days (EPA 2007).
-------
State requirements SUMMARY
State
New York
North
Carolina
North Dakota
Sediment basin
storage volume
(ft3/acre drained)
3,600 (2004 TDD
Section 7). For
alternate size
standards, see New
York's Standards and
Specifications for
Erosion and Sediment
Control (August
2005).
1,800 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007)
Sediment basin (design parameters)
sediment basins and/or sediment traps should
be used. At a minimum, silt fences, vegetative
buffer strips, or equivalent sediment controls
are required for all down slope boundaries
(and for those side slope boundaries deemed
appropriate as dictated by individual site
conditions) of the construction area unless a
sediment basin providing storage for a
calculated volume of runoff from a 2-year,
24-hour storm or 3,600 ft3 of storage per acre
drained is provided.
The New York August 2005 Standards and
Specification for Sediment and Erosion
Control states that the minimum sediment
storage volume of the basin, as measured
from the bottom of the basin to the elevation
of the crest of the principal spillway shall be
at least 3,600 ft3/acre draining to the basin.
This 3,600 ft3 is equivalent to one inch of
sediment per acre of drainage area. The entire
drainage area is used for this computation,
rather than the disturbed area above, to
maximize trapping efficiency. The length to
width ratio shall be greater than 2:1, where
length is the distance between the inlet and
outlet. A wedge shape shall be used with the
inlet at the narrow end.
The 2006 Erosion and Sediment Control
Planning and Design Manual states that the
sediment storage volume of the basin, as
measured to the elevation of the crest of the
principal spillway, is at least 1,800 ft3/acre for
the disturbed area draining into the basin
(1,800 ft3 is equivalent to a 1/2 inch of
sediment per acre of basin drainage area) for a
maximum of 100 acres. See more details on
basin design provided in manual (EPA 2007).
The 2004 permit states that (for 10 or more
acres) the basins shall be sized to provide
3,600 ft3 of storage below the outlet pipe per
acre drained to the basin. Alterative designs
may be used which provide storage below the
outlet for a calculated volume of runoff from
a 2-year, 24-hour storm and provides not less
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The EPA 2007 literature notes to see details
in New York's Standards and Specifications for
Erosion and Sediment Control (August 2005).
The EPA 2007 literature notes a sediment basin
storage volume of 1,800 ftVacre drained.
The 2004 TDD Section 7 notes a sediment basin
storage volume of 1,800 ft3/acre drained.
Numeric standard
None (EPA 2007).
None. None listed in EPA 2007 or 2002
TDD Appendix A.
None (EPA 2007).
Soil stabilization
7 days (Permit No. GP-0-
08-001)
None specified. 2002
TDD Appendix A
confirms no stabilization
within 14 days. 20 acres
of total disturbance at any
given time for areas
discharging to high
quality waters (2002 TDD
Appendix A).
Not specified (EPA 2007).
2002 TDD Appendix A
confirmed no stabilization
within 14 days.
-------
State requirementsSUMMARY
State
Sediment basin
storage volume
(ft3/acre drained)
Sediment basin (design parameters)
Sediment basinnotes/references
Numeric standard
Soil stabilization
than 1,800 ft of storage below the outlet pipe
from each acre drained to the basin. (EPA
2007).
Ohio
1,800 (EPA 2007;
2004 TDD Section 7)
N/A
The 2006 Rainwater and Land Development
Manual states that for areas less than 100 acres,
the volume of the dewatering zone shall be a
minimum of 1,800 ftVacre of drainage (66.7
yd3/acre) (EPA 2007).
None (EPA 2007).
7 days, or 2 days if near
stream (EPA 2007).
Oklahoma
3,600 (EPA 2007;
2004 TDD Section 7)
The EPA 2007 literature notes that the 2002
general permit states that for 10 or more acres
drained the basin shall provide storage for a
2-year, 24-hour storm event or 3,600 ft3 of
storage per acre. The 2002 TDD Appendix A
notes 3,600 ftVacre.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
None (EPA 2007).
14 days (EPA 2007).
Oregon
3,600 (EPA 2007)
N/A
Per the Oregon Erosion and Sediment Control
Manual (April 2005), basin size shall be 3,600
ft3/acre and be designed by a professional
engineer. The 2004 TDD Section 7 notes a
sediment basin storage volume of 1,800 ft3/acre
drained.
If discharging to a 303(d) listed
waterbody or a waterbody with a TMDL
for sediment and turbidity, sampling for
turbidity is required to meet a 160 NTU
benchmark. If unable to meet
benchmark, an Action Plan using a
BMP such as water treatment using
electro-coagulation, chemical
flocculation or filtration shall be
implemented. (OR CGP)
1 day (PG assumed). The
EPA 2007 literature notes
apply temporary or
permanent soil
stabilization measures
immediately on all
disturbed areas as grading
progresses.
Pennsylvania
5,000 (EPA 2007)
The EPA 2007 literature notes that the 2005
permit states that (1) A sediment storage zone
of 1,000 ft3 per disturbed acre within the
watershed of the basin is required; (2) A
dewatering zone of 5,000 ft3 for each acre
tributary to the basin is to be provided.
Reductions in the dewatering zone are
allowed unless the basins is in a HQ or EV
watershed, however the minimum required
dewatering zone is at least 3,600 ft3/acre.
(3,600 to 6,000 ft3/acre + 1,800 ft3/acre =
4,800 to 6,000 ft3/acre, assumed 5,000
ft3/acre). The 2002 TDD Appendix A notes a
5-year runoff event for water quality
treatment.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres. The 2002 TDD Appendix A states that
basins volumes should drain no quicker than 4
days and no longer than 7 days.
None (EPA 2007).
Not specified (EPA 2007).
2002 TDD Appendix A
confirmed no stabilization
within 14 days.
Rhode Island
1,800 (2004 TDD
Section 7)
The 2004 TDD Section 7 states that for a state
program that did not note a sediment basin
size, EPA assumed based on BPJ that the
baseline size was 1,800 ft3/acre. The EPA
The Stormwater Design and Installation Standards
Manual and the Soil Erosion and Sediment
Control Handbook were not reviewed.
PG estimated no numeric standard.
None (EPA 2007). The 2002 TDD
Appendix A notes 80 to 90 percent TSS
reduction; however, PG could not
14 days (EPA 2007).
-------
State requirements SUMMARY
State
South
Carolina
South Dakota
Tennessee
Texas
Sediment basin
storage volume
(ft3/acre drained)
3,600 (EPA 2007;
2004 TDD Section 7)
3 600 (EPA 2007'
2004 TDD Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
2007 literature notes no sizing criteria in
permit. The 2002 TDD Appendix A notes a
10-year runoff event for water quality
treatment.
The EPA 2007 literature notes basin sizing
requirements for 10 or more acres provide
storage for a 10-year, 24-hour storm event or
at least 3,600 ft3/acre. (10-year, 24-hour Soil
Conservation Service (SCS) Type II, or Type
III (coastal zone) storm event). The 2002
TDD Appendix A notes 3,600 ft3/acre.
The 2002 TDD Appendix A notes a 5-year
runoff event for water quality treatment. (PG
could not find reference for this).
The EPA 2007 literature notes that the 2005
permit states to design for a 2-year, 24-hour
storm for 10 or more acres. Also, the 2002
Erosion and Sediment Control Handbook
states that the total storage volume of the
basin at the spillway should be at least 134
cubic yards (3,618 ft3) per acre of drainage
area. The volume of the permanent pool must
be at least 67 cubic yards (1,809 ft3) per acre
of drainage area and the volume of dry
storage must be at least an additional 67 cubic
yards (1,809 ft3) per acre of drainage area.
The emergency spillway should be able to
handle a 2-year or 5-year, 24-hour storm
event. The outlets for the basin should pass
the peak runoff expected from the
contributing drainage area for a 25-year, 24-
hour storm.
The EPA 2007 literature notes that the 2003
Permit states that sediment basins are required
where feasible for common drainage locations
that serve an area with 10 or more acres
disturbed at one time. The temporary (or
permanent) sediment basin should provide
storage for a calculated volume of runoff from
a 2-year, 24-hour storm from each disturbed
acre drained. Where rainfall data is not
available or a calculation cannot be
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
Numeric standard
confirm for active construction runoff.
PG estimated no numeric standard. The
EPA 2007 literature notes 80 percent of
TSS removal for drainage areas > 5
acres. The 2002 TDD Appendix A notes
80 percent TSS reduction; however, PG
could not confirm for active
construction runoff.
None (EPA 2007).
None (EPA 2007).
None, except for concrete batch plants
(EPA 2007)
Soil stabilization
14 d A
possible (ASAP), but no
later than 14 days (EPA
9007^
ZUU / ).
14 days (EPA 2007).
1 5 days, Pre-construction
vegetative ground cover
y '
more than 10 days before
grading or earth moving
unless the area is seeded
and/or mulched or other
temporary cover is
installed. Construction
must be phased for
projects in which over 50
acres of soil will be
disturbed No more than
disturbance is allowed at
any time during the
construction project (EPA
2007).
14 days (EPA 2007)
-------
State requirements SUMMARY
State
Utah
Vermont
Virginia
Sediment basin
storage volume
(ft3/acre drained)
3,600 (EPA 2007;
2004 TDD Section 7)
1,800 (2004 TDD
Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
performed, a sediment basin providing 3,600
ft3 of storage per acre drained is required
where attainable until final stabilization of the
site. The 2002 TDD Appendix A notes 3,600
ftVacre.
The EPA 2007 literature notes that the 2002
permit says for 10 or more acres basin storage
shall provide for a 10-year, 24-hour storm
event, or 3,600 ftVacre. Permit No.:
UTRIOOOOO (10/31/200) states "...sediment
basin that provides storage for a 10-year, 24-
hour storm event, a calculated volume of
runoff for disturbed acres drained, or
equivalent control measures, until final
stabilization of the site. Where calculations
are not performed, a sediment basin providing
3,600 ft3 of storage per acre drained (a 1 inch
storm event)"
The EPA 2007 literature notes basin sizing of
3,600 ft3/acre for moderate risk only, and no
sizing criteria in permit. The 2004 TDD
Section 7 states that for a state program that
did not note a sediment basin size, EPA
assumed based on BPJ that the baseline size
was 1,800 ftVacre.
The EPA 2007 literature notes that the
Virginia Erosion and Sediment Control
regulations state that sediment traps and
sediment basins shall be designed and
constructed based on the total drainage area to
be served by the trap or basin. Surface runoff
from disturbed areas that is comprised of flow
from drainage areas greater than or equal to
three acres shall be controlled by a sediment
basin. The minimum storage capacity of a
sediment basin shall be 134 cubic yards per
acre (3,618 ft3) of drainage area. The outfall
system shall, at a minimum, maintain the
structural integrity of the basin during a 25-
year, 24-hour duration storm event. Runoff
coefficients used in runoff calculations shall
correspond to a bare earth condition or those
conditions expected to exist while the
sediment basin is used. The 2002 TDD
Sediment basin notes/references
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
EPA 2007 literature found no sizing criteria and
found 3,600 ft3/acre for moderate risk only;
therefore, assumed 1,800 per BPJ from 2004 TDD
Section 7.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
Numeric standard
None (EPA 2007).
Vermont's CGP issued February, 2008
contains a numeric action level of 25
NTU for moderate-risk sites.
None (EPA 2007)
Soil stabilization
14 days (EPA 2007).
2 1 days, for low or
moderate risk activities
only (EPA 2007).
7 days (EPA 2007)
-------
State requirements SUMMARY
State
Washington
Washington,
Small Parcel
West Virginia
Wisconsin
Sediment basin
storage volume
(ft3/acre drained)
3,600 (eastern WA
only). For alternate
size standards, see
WABMPC241.
3,600 (EPA 2007;
2004 TDD Section 7)
1,800 (2004 TDD
Section 7). For
alternate size
standards, see WI
DNR Conservation
Practice Standard
1064.
Sediment basin (design parameters)
Appendix A notes that sediment basins
required for sites of 10 acres or more (except
those with final stabilization); for sites less
than 10 acres, same units required but only for
sideslope and downslope boundaries of
construction sites.
The 2002 TDD Appendix A notes a 24-
hour/6-month storm for water quality
treatment. 2-year (or 10-year peak if
warranted) OR Rational Method See Eastern
Washington BMP C241
(http://www.ecy.wa.gOV/pubs/0410076/7.pdf).
Western Washington has the same storm
events but does not specifically mention 3,600
ftVacre.
The 2002 TDD Appendix A notes a 24-
hour/6-month storm for water quality
treatment.
The EPA 2007 literature notes that the 2002
permit states sediment basins and traps will be
installed with 3,600 ft3 of storage, measured
from the bottom elevation of the structure to
the top of the riser or weir, per acre of
drainage and will have draw down times of 48
to 72 hours. The 2002 TDD Appendix A
notes runoff from a 2-year storm required for
water quality treatment (PG could not confirm
with state literature).
The EPA 2007 literature notes in the
Technical Standards document that basins
shall be used for greater than 5 to 100 acres.
The sizing criteria for determining treatment
surface area of a sediment basin are based on
the soil texture and peak outflow during the 1-
year, 24-hour design storm. The overflow
Sediment basin notes/references
The EPA 2007 literature notes basin requirements
are different for western and eastern parts of
State see manuals. The 2004 TDD Section 7
notes a sediment basin storage volume of 1,800
ft3/acre drained.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
Numeric standard
Statewide standard varies with
background. PG noted that the WAC
173-201 A-030 has been replaced with
the WAC 173-201A-200 Freshwater
designated uses and criteria (updated
2006). Table 200 (1) (e) contains
updated aquatic life turbidity criteria.
The EPA 2007 literature states that the
Water Quality Standards for Surface
Waters of the State of Washington
WAC 173-201A-030 (1) (vi) states that
turbidity shall not exceed 5 NTU over
background turbidity when the
background turbidity is 50 NTU or less,
or has more than a 10 percent increase
in turbidity when the background
turbidity is more than 50 NTU.
None (EPA 2007).
The EPA 2007 literature notes that the
current standard in Wisconsin (NR
151.11pg409) requires construction
sites to implement erosion and sediment
controls to reduce to the maximum
extent practicable 80 percent of the
sediment load carried in runoff on an
Soil stabilization
Both the EPA literature
and the 2002 TDD
Appendix A note that
stabilization varies by
time of year and location
instate. West of the
Cascade Mountains Crest:
During the dry season
(May 1-Sept. 30): 7 days;
during the wet season
(October 1-April 30): 2
days.
7 days (EPA 2007).
Not specified (EPA 2007).
2002 TDD Appendix A
confirmed no stabilization
within 14 days.
-------
State requirements SUMMARY
State
Wyoming
Puerto Rico
District of
Columbia
Sediment basin
storage volume
(ft3/acre drained)
1,800 (2004 TDD
Section 7)
3,600 (EPA 2007;
2004 TDD Section 7)
Sediment basin (design parameters)
spillway should be designed to carry the peak
rate of runoff expected from a 10-year, 24-
hour design storm. The 2004 TDD Section 7
states that for a state program that did not note
a sediment basin size, EPA assumed based on
BPJ that the baseline size was 1,800 ft3/acre.
The EPA 2007 literature notes No sizing
criteria in the permit, and the 1999 Urban
Best Management Practice (BMP) manual
says use basins for 5 to 100 acres. The 2004
TDD Section 7 states that for a state program
that did not note a sediment basin size, EPA
assumed based on BPJ that the baseline size
was 1,800 fVVacre.
Basin sizing for 2-year, 24-hour storm (EPA
2007).
Sediment basin notes/references
1,800 ftVacre based on 2004 TDD Section 7.
The 2004 TDD Section 7 notes sediment basin
drainage requirements for drainage areas > 10
acres.
Numeric standard
annual basis, compared to a baseline of
no sediment or erosion controls.
Standard varies with background. The
EPA 2007 literature notes that for cold
water fisheries and drinking water
supplies turbidity level increases must
be less than 10 NTUs; for warm water
/nongame fisheries turbidity level
increases must be less than 15 NTUs.
However, an exception shall apply to
the North Platte River from Guernsey
Dam to the Nebraska line during the
annual "silt run" from Guernsey Dam.
The 2002 TDD Appendix A notes
turbidity levels must be less than 10 to
15 NTUs
None (EPA 2007)
Soil stabilization
28 days, temporary
stabilization (such as
cover crop plantings,
mulching or erosion
controls blankets, surface
roughening, etc.) for
exposed soil areas where
activities have
permanently or
temporarily ceased should
be installed whenever
practicable in areas where
expected for 28 days or
more (EPA 2007).
14 days (EPA 2007)
-------
State requirements: Environmental Protection Agency (EPA) 2007
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Sediment basin general
requirements
Basin sizing of 1,800 ftVacre.
Basin sizing of 1,800 ftVacre
plus 1.5 ft for sediment
accumulation generally
designed to remove medium silt
(62 microns) particles.
Basin sizing of 3,600 ft3/acre or
2-year, 24-hour.
Basin sizing of 3,600 ft3/acre or
10-year, 24-hour.
Several standards exist,
including a basin sizing of 3,600
ftVacre as well as a settling
velocity approach
Colorado Department of
Transportation (CDOT) specifies
3,600 ftVacre sediment basin
sizing.
Sediment basins notes/other
requirements
8-hour detention time for sites greater
than 5 acres.
Construction General Permit (CGP)
Colorado requires preparation of a
stormwater pollution prevention plan
(SWPPP) but does not specify
specific sizing for BMPs. No
statewide erosion and sediment
control manual exists Extensive
requirements exist at the local level.
Specifically, Douglas County requires
that disturbed areas be drill seeded,
crimped and mulched, or permanently
landscaped within 30 days from the
start of land disturbance activities or
within 7 days of the substantial
Soil stabilization
Notes/other requirements
CGP
Not specified
Douglas County requires that
disturbed areas be drill seeded
and crimp mulched, or
permanently landscaped,
within 30 days from the start
of land disturbance activities
or within 7 days of the
substantial completion of
grading and topsoiling
operations, whichever
duration is shorter.
Days
13
14
14
see
notes
Numeric standard
No
No
No
80 percent removal of TSS
from flows exceeding
predevelopment levels, where
practicable.
California's draft CGP
includes turbidity effluent
levels of 1,000 NTU. If Active
Treatment Systems are used,
the daily flow-weighted
average is 10 NTU and the
maximum for any single
sample is 20 NTU.
No
Water quality
requirements
There are no standards,
but the manual
recommends that
detention basins provide
1/2 inch of runoff storage
and that discharge be at
the 2-year
predevelopment rate to
minimize downstream
erosion.
None
None
None
85 percent of storm
events from specific
development categories
must be infiltrated or
treated per the Standard
Urban Stormwater
Mitigation Plan
(SUSMP).
None
Other notes
-------
State requirements: Environmental Protection Agency (EPA) 2007
State
Connecticut
Delaware
Florida
Florida, DEP,
Northern
District (only
applies in NW
Florida)
Florida, South
Florida Water
Management
Sediment basin general
requirements
Basin sizing of 3,600 ft3/acre.
Basin sizing of 3,600 ft3/acre.
Basin sizing of 3,600 ft3/acre.
Sediment basins notes/other
requirements
completion of grading and topsoiling
operations, whichever duration is
shorter.
Required for sites greater than 2
acres.
Soil stabilization
Notes/other requirements
Where construction activities
have permanently ceased or
have temporarily been
suspended for more than 7
days, or when final grades are
reached in any portion of the
site, stabilization practices
shall be implemented within
three days. Areas that will
remain disturbed but inactive
for at least 30 days shall
receive temporary seeding.
Areas that will remain
disturbed beyond the planting
season, shall receive long-
term, nonvegetative
stabilization sufficient to
protect the site through the
winter.
Days
3
14
7
Numeric standard
80%TSS [A goal of 80
percent removal of TSS - 2004
Connecticut Stormwater
Quality Manual, Chapter 6.]
No
No
Water quality
requirements
[Requires treatment of] 1
inch, which equals 90
percent of average annual
runoff.
[Recommended treatment
volume for] 2 inches of
rainfall, up to 1 inch of
runoff. Goal is to remove
80 percent of the annual
TSS load, classified as a
post construction
standard.
Requirements vary by
region. Generally, it
appears that 0.5 inch to 1
inch of runoff is a
recommended treatment
volume.
Other notes
-------
State requirements: Environmental Protection Agency (EPA) 2007
State
District
(General,
Standard
General,
Noticed
General and
Individual
Permits)
Florida,
Southwest
Florida Water
Management
District
Florida, St.
Johns River
Water
Management
District
Florida,
Suwannee
River Water
Management
District
Georgia
Hawaii
Sediment basin general
requirements
Basin sizing of 1,800 ft3/acre.
Basin sizing of 3,600 ft3/acre or
2-year, 24-hour for drainage
areas > 10 or more acres.
Sediment basins notes/other
requirements
Soil stabilization
Notes/other requirements
Days
14
30
Numeric standard
Receiving water turbidity
standard cannot increase
turbidity by more than 25
NTU in warm waters and 10
NTU in cold water trout
streams. Allowable turbidity in
effluent varies based on site
size and receiving stream
drainage area.
Water quality
requirements
Requires treatment of 85
percent of annual runoff,
which equates to 1.2-inch
storm event depth.
Reduce the average
annual TSS loadings by
80 percent based on the
average annual TSS
loadings from all storms
less than or equal to the
2-year, 24-hour storm.
Reduce the post-
development loadings of
TSS so that the average
annual TSS loadings are
no greater than
Other notes
New development
standards apply to
sites that create
5,000 square feet
of impervious area
or disturb 5,00 or
more square feet
The Hawaii
Department of
Health's Clean
Water Branch
(CWB) is
responsible for
administrating the
state's stormwater
management plan.
No numeric
requirements for
stormwater
-------
State requirements: Environmental Protection Agency (EPA) 2007
State
Sediment basin general
requirements
Sediment basins notes/other
requirements
Soil stabilization
Notes/other requirements
Days
Numeric standard
Water quality
requirements
predevelopment loadings.
To the extent practicable,
maintain post-
development peak runoff
rate and average volume
at levels that are similar
to predevelopment levels.
For design purposes,
post-development peak
runoff rate and average
volume should be based
on the 2-year/24-hour
storm.
Other notes
pollutant removal
have been
established at the
state level, but
regional and
municipal
regulations are in
place. For
example, the city
and county of
Honolulu has
developed a
stormwater
management plan
and BMP manual
for controlling
stormwater within
the limits of the
city and the
county. The
counties of Hawaii,
Maui, Kauai, and
the city and county
of Honolulu are
responsible for
planning and
zoning in urban
districts. They
have additional
responsibilities that
include state-
mandated county
regulatory
programs dealing
with erosion
control, urban
design, and other
areas. The Hawaii
Coastal Nonpoint
Pollution Program
Management Plan,
Part III and
Hawaii's
Implementation
Plan for Polluted
Runoff Control
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o
State requirements: Environmental Protection Agency (EPA) 2007
State
Idaho
Illinois
Indiana
Sediment basin general
requirements
Basin sizing of 3,600 ft3/acre or
2-year, 24-hour for drainage
areas > 10 or more acres.
No sizing criteria in permit.
No sizing criteria in permit.
Basin sizing of 3,600 ft3/acre.
The 2002 permit states that a
sediment basin shall be installed
for drainage area more than 10
acres disturbed. (Flows from
upland areas that are undisturbed
may be diverted around the
basin).
Sediment basins notes/other
requirements
The 2002 Illinois Urban Manual
states that the basin requirements
shall be based on a 2-year, 24-hour
storm or 134 cubic yards/acre (i.e.,
3,600 ft3/acre) whichever is greater.
Exist for some areas in the state.
The 2006 Iowa Construction Site
Erosion Control Manual states that
the size of the sediment basin, is as
measured from the bottom of the
basin to the principal spillway and
should provide at least 3,600 ft3 of
storage per acre of drainage. This
provides storage equal to 1 inch of
runoff per acre. Likewise, 1,800 ft3
amounts to 1/2 inch of sediment
storage per acre. The basin should be
cleaned when the volume of sediment
reaches 900 ftVacre. At this time, the
cleanout shall be performed to restore
the original design capacity of the
basin. At no time should the sediment
level be permitted to build higher
than 1 ft below the principal outlet.
Soil stabilization
Notes/other requirements
Stabilization within 14 days
(unless covered with snow or
construction will resume
within 2 1 days).
Stabilization within 14 days
(unless covered with snow or
construction will resume
within 2 1 days).
Days
14
14
15
14
Numeric standard
No
Not applicable. Only in certain
parts of Indiana (e.g., 80
percent of TSS removal in
Marion County) (EPA 2007).
No
Water quality
requirements
Other notes
contain
descriptions of
management
measures for urban
areas to address
runoff. These are
the requirements
described in this
summary.
EPA issues permits
in Idaho because
the state has not
been delesated
authority to issue
NPDES
construction
permits.
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>
State requirements: Environmental Protection Agency (EPA) 2007
State
Kansas
Kentucky
Louisiana
Sediment basin general
requirements
The 2007 permit requires a
storage capacity of 3,600 ft3/acre
and the Sediment Basin Design
Criteria in the permit states,
"rational method or other
equivalent runoff calculations
based on storage of a 2.6-inch
rainfall event with a minimum
runoff coefficient of 0.77 for
disturbed acreage and
appropriate runoff coefficients
for undisturbed acreage must be
provided to determine the
revised storage volume
requirement."
The 2002 permit requires a basin
sizing of 3,600 ft3/acre for
drainage locations >10 acres.
For 10 or more disturbed acres
either the smaller of 3,600
ft3/acre or a 2-year, 24-hour
storm. This does not apply to
flows from off-site areas and
flows from on-site areas that are
either undisturbed of have
undergone final stabilization
where such flows are diverted
around the sediment basin. For
drainage locations serving less
than 10 acres, smaller sediment
basins and/or sediment traps
should be used. At a minimum,
silt fences, vegetative buffer
strips, or equivalent sediment
controls are required for all
downslope boundaries of the
construction area unless a
sediment basin providing storage
for a calculated volume of runoff
from a 2-year, 24-hour storm or
Sediment basins notes/other
requirements
The field guide for Missouri and
Kansas says that for drainage areas of
20 acres or less, the sediment storage
shall be 1,800 ft3/acre with a
detention time of at least 24 hours.
The 2007 Draft Kentucky BMP
Manual requires basin sizing of 3,600
ft3/acre, not to exceed 10 acre-feet for
areas 5 to 120 acres. The goal is to
reduce TSS by 80 percent for the 10-
year, 24-hour storm, or provide a
detention time of 24 to 48 hours for
the 10-year, 24-hour storm.
Soil stabilization
Notes/other requirements
None specified; state that
"time should be minimized."
Stabilization within 14 days
(unless covered with snow or
construction will resume
within 2 1 days).
Days
N/A
14
14
Numeric standard
No
80% TSS (EPA 2007). A goal
of 80 percent removal of TSS
from flows that exceed
predevelopment levels (2002
General KPDES Permit for
Stormwater Point Source
Discharges, Construction
Activity, page IV-2)
There are standards for
permitted support activities
related to a construction site
("cement and concrete
facilities hot mix
asphalt/asphaltic concrete
facilities, stockpiles of sand
and gravel, and non-process
area stormwater from cement,
concrete, and asphalt
facilities). They establish
monthly monitoring
requirements and discharge
limitations for flow
(parameters: TSS, TOC, Oil &
Grease, and allowable ranges
ofpH).
Water quality
requirements
Other notes
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State requirements: Environmental Protection Agency (EPA) 2007
State
Maine
Maryland
Massachusetts
Sediment basin general
requirements
3,600 ft3 of storage per acre
drained is provided.
No sizing criteria in permit.
EPA issues permit.
Sediment basins notes/other
requirements
The 2003 Erosion and Sediment
Control BMPs Manual states that the
capacity of the sediment basin shall
be equal to the stormwater volume to
be detained plus the volume of
sediment expected to be trapped.
Periodic removal of sediment will be
necessary to maintain basin's
capacity. Temporary basins having
drainage areas of 5 acres or less and a
total embankment height of 5 feet or
less may be designed with less
conservative criteria. Any excavated
pond with a drainage area in excess
of 5 acres, or spring flow in excess of
100 gallons per minute must be
designed in accordance with
embankment pond criteria. Excavated
ponds must be designed to be drained
within a 10-day period.
The 1994 Erosion and Sediment
Control requirements states that the
minimum storage volume for
sediment basins is 3,600 ft3/acre of
contributing drainage area, equally
divided between wet storage and dry
storage. The specified drawdown
time from the crest of the basin to the
permanent pool level is 10 hours
(minimum). The state standards do
not specify minimum site sizes where
sediment basins are required, but it is
assumed based on the sediment trap
applicability criteria that sediment
basins are required for contributing
drainage areas of 10 or more acres.
The 2003 Erosion and Sediment
Control guidelines says the drainage
area for the sediment basin should be
no more than 100 acres with a life
span of 3 years unless it is designed
as a permanent structure. The
Soil stabilization
Notes/other requirements
Operators must stabilize with
mulch, or other non-erodible
cover, any exposed soils that
will not be worked for more
than 7 days. They must
stabilize areas within 75 feet
of a wetland or waterbody
within 48 hours of the initial
disturbance of the soil or
before any storm event,
whichever comes first. They
are also required to remove
any temporary control
measures, such as silt fences,
within 30 days after
permanent stabilization is
attained
Stabilization is 14 days (7
days for steep slopes).
CGP reference.
Days
14
14
14
Numeric standard
No
No
No
Water quality
requirements
Other notes
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oo
State requirements: Environmental Protection Agency (EPA) 2007
State
Michigan
Minnesota
Sediment basin general
requirements
For 10 or more disturbed acres;
(1) The basins must provide
storage below the outlet pipe for
a calculated volume of runoff
from a 2-year, 24-hour storm
from each acre drained to the
basin, except that in no case
shall the basin provide less than
1,800 ft3 of storage below the
outlet pipe from each acre
drained to the basin, (2) Where
Sediment basins notes/other
requirements
sediment basin should have a
minimum volume based on 1/2 inch
of storage for each acre of drainage
area. This volume equates to 1,800 ft3
of storage or 67 cubic yards for each
acre of drainage area. The sediment
basin should have a total spill way
capacity for a 10-year peak flow with
a 1-foot freeboard. Freeboard is the
difference between the design flow
elevation in the emergency spillway
and the top elevation of the
embankment.
1998 Guidebook for Best
Management Practices for Michigan
Watersheds provides sediment basin
design recommendations (see longer
write-up for details). The 1998
Guidebook for Best Management
Practices for Michigan Watersheds
provides sediment basin design
recommendations. A straightforward
method requires a storage volume
that is equal to one-half inch of runoff
from the contributing watershed. (For
residential areas, 1/2 inch of runoff
would be about a 1-year rainfall event
in Michigan). For the high percentage
of particulate pollutant removal, the
detention basin should be designed so
that it will take at least 24 hours to
drain the entire volume stored. (For
more information, see chapter 3 of
the guidebook.)
Soil stabilization
Notes/other requirements
Stabilization within 15
calendar days after final
grading or the final earth
change has been completed.
Steeper than 3:1, 7 days, 10:1
to 3:1, 14 days, flatter than
10:1,21 days
Days
15
7, 14 or
21 (see
notes)
Numeric standard
No
No - Where an alternative,
innovative treatment system is
proposed and demonstrated by
calculation, design or other
independent methods to
achieve 80 percent TSS
removal a 2-year monitoring
plan to sample runoff from the
proposed method must be
Water quality
requirements
Other notes
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State requirements: Environmental Protection Agency (EPA) 2007
State
Mississippi
Missouri
Sediment basin general
requirements
no such calculation has been
performed, a temporary (or
permanent) sediment basin
providing 3,600 ft3 of storage
below the outlet pipe per acre
drained to the basin shall be
provided where attainable until
final stabilization of the site.
The 2005 general permit states
that for 10 or more acres
disturbed at one time, a
temporary (or permanent)
sediment basin providing at least
3,600 ftVacre drained shall be
provided until final stabilization
of the site.
The 2007 permit states that
basins are needed for 10 acres or
more, with a basin sizing at least
3,600 ftVacre. In valuable water
resource areas the sediment
basin needs to contain 1/2 inch
of sediment from the drainage
and withstand the 2-year, 24-
hour storm. The basin spillway
or embankment requires
stabilization to minimize
potential for erosion.
Sediment basins notes/other
requirements
The Planning and Design Manual
states that the maximum allowable
drainage area into the basin shall be
25 acres. The design capacity of the
basin must be at least 67 yd3/acre
(1809 fVVacre). The capacity of the
basin may be estimated by 40% x
Height x Surface Area. The basin
spillway shall be designed to handle
peak flow from a 10-year, 24-hour
storm event. If a principal spillway is
used in conjunction with an
emergency spillway, the principal
spillway shall have a minimum
capacity of 0.2 cfs per acre of
drainage area when the water surface
is at the crest of the emergency
spillway. The embankment of the
sediment basin shall be temporarily
seeded within 15 days after its
completion. The basin should be
designed according the following data
sheet (see more detailed summaries in
the manual).
The 1995 Erosion and Sediment
Manual says the contributing area is
recommended to be 20 acres or less
and sized to store a minimum of
1,800 ft3 per disturbed acre with a
detention of at least 24 hours. The site
should be vegetated and stabilized
immediately after construction.
Soil stabilization
Notes/other requirements
Within 7 calendar days when
a disturbed area will be left
undisturbed for 30 days or
more.
Stabilization at 14 days;
however if the slope of the
area is greater than 3: 1 (3 feet
horizontal to 1 foot vertical)
or if the slope is greater than 3
percent and greater than 150
feet in length, then interim
stabilization within 7 days of
ceasing operations on that part
of the site is required.
Days
7
7 or 14
(see
notes)
Numeric standard
No
Per the Ivlissoun State
Operating Permit General
Permit MO-R109000
3/8/2002: Construction site
discharges shall not violate
Missouri Code of State
Regulations General Water
Quality Standards 10 CSR 20
7.031(3) or exceed a
maximum settleable solids
concentration of 2.5 ml/L per
hour for each stormwater
outfall. If the disturbed area is
Water quality
requirements
Other notes
Different general
permits exist for
large and small ( 1
to < 5 acres).
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State requirements: Environmental Protection Agency (EPA) 2007
State
Montana
Nebraska
eva a
Sediment basin general
requirements
No sizing criteria in permit.
Sediment basins required for 5
acres or more in size. Where
slopes are equal to or steeper
than 3:1, sediment basins may be
required for smaller drainage
areas.
The 2002 permit states that basin
requirements for drainage areas
> 10 acres shall provided storage
of 3,600 ftVacre or for a 2-year,
24-hour storm event for each
disturbed acre. For a drainage
Sediment basins notes/other
requirements
The Erosion and Sediment Control
Manual states that desilting basins are
appropriate for areas of disturbed soil
between 5 acres and 10 acres in size.
Desilting basins shall be designed to
have a capacity equivalent to 100 m3
(1500 ft3) of storage (as measured
from the top of the basin to the
principal outlet,) per hectare (acre) of
contributory area. This design is less
than that required to capture 0.01 mm
(0.0004 in) particle size, but larger
than that required to capture particles
0.02 mm (0.0008 in) or larger. The
depth must be no less than 1 m (3 ft)
nor greater than 1.5 m (5 ft). Basins
shall be designed to drain within 72
hours following storm events.
None
See design specifications from the
Department of Conservation and
Natural Resources (DCNR) and 1994
BMP manual.
Soil stabilization
Notes/other requirements
Temporary or permanent
seeding shall be established as
soon as possible after grading
and clearing activities are
completed, and during interim
periods on areas that are not
being actively worked.
Whenever exposed soils are
not to be graded for 30 days
or more, temporary or
permanent seeding needs to be
initiated, unless other
stabilization methods are used
or such need can be justified
as unnecessary due to
mitigating conditions present
at the site.
Days
N/A
30 (see
notes)
14
Numeric standard
near a Valuable Resources
Water, settleable solids may
not exceed 0. 5 ml/L per hour.
BMPs must minimize or
prevent significant sediment
(as defined in Part VI of the
General Permit p. 28) from
leaving the construction site.
Significant sediment means
sediment, solids, or other
wastes discharged from
construction site, or a facility
or activity regulated under the
General Permit that exceeds
1.0 cubic foot in volume in
any area of 100 square feet
that may enter state surface
water or a drainage that leads
directly to state surface water.
No
No
Water quality
requirements
Other notes
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State requirements: Environmental Protection Agency (EPA) 2007
State
New
Hampshire
New Jersey
Sediment basin general
requirements
location which serves ten or
more acres disturbed at one time
and where a temporary sediment
basin or equivalent controls is
not attainable, smaller sediment
basins and/or sediment traps
should be used.
EPA's CGP applies.
Sediment basins notes/other
requirements
See the design specifications from the
1992 Erosion and Sediment Control
Handbook.
New Jersey Erosion and Sediment
Control and Stormwater Management
Requirements state that Sediment
Control Tanks shall be sized
accordingly: 1 cubic foot of storage
for each gallon per minute of pump
discharge capacity. Tanks may be
connected in series to increase
effectiveness.
Soil stabilization
Notes/other requirements
None
Days
14
N/A
Numeric standard
Yes, see monitoring. Must
treat any uncontaminated
excavation dewatering
discharges to remove TSS and
turbidity. Must sample at a
location before mixing with
stormwater at least once per
week during weeks when
discharges occur. TSS must
meet monthly average and
maximum daily TSS
limitations of 50 mg/L and
100 mg/L, respectively.
Records of any sampling and
analysis must be maintained
and kept with the SWPPP for
at least 3 years after final site
stabilization. Applicable only
to certain size sites.
A major development project
that creates at least 0.25 acres
of new or additional
impervious surface must
include stormwater
management measures that
reduce the average annual TSS
load in the development site's
post-construction runoff by 80
percent. In addition, these
stormwater management
measures must reduce the
average annual nutrient load in
the post-construction runoff by
the maximum extent feasible.
For various BMPs for more
detailed TSS and nutrient
removal rates, see Chapter 4 of
the New Jersey Stormwater
Water quality
requirements
Other notes
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State requirements: Environmental Protection Agency (EPA) 2007
State
New Mexico
New York
North Carolina
Sediment basin general
requirements
EPA Region 6 issues permit
the 2003 general permit states
that for 10 or more disturbed
acres at one time, a temporary
(or permanent) sediment basin
providing at least 3,600 ft3/acre
drained shall be provided until
final stabilization of the site. For
drainage locations which serve
10 or more disturbed acres at
one time and where a temporary
sediment basin or equivalent
controls is not attainable, smaller
sediment basins and/or sediment
traps should be used. For
drainage locations serving less
than 10 acres, smaller sediment
basins and/or sediment traps
should be used. At a minimum,
silt fences, vegetative buffer
strips, or equivalent sediment
controls are required for all
down slope boundaries (and for
those side slope boundaries
deemed appropriate as dictated
by individual site conditions) of
the construction area unless a
sediment basin providing storage
for a calculated volume of runoff
from a 2-year, 24-hour storm or
3,600 ft3 of storage per acre
drained is provided.
Sediment basins notes/other
requirements
See details in New York's Standards
and Specifications for Erosion and
Sediment Control (August 2005).
The 2006 Erosion and Sediment
Control Planning and Design Manual
states that the sediment storage
volume of the basin, as measured to
the elevation of the crest of the
principal spillway, is at least 1,800
ft3/acre for the disturbed area draining
Soil stabilization
Notes/other requirements
Days
14
14
N/A
Numeric standard
Best Management Practices
Manual.
No
No
Water quality
requirements
Other notes
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to
oo
State requirements: Environmental Protection Agency (EPA) 2007
State
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Sediment basin general
requirements
The 2004 permit states that (for
10 or more acres) the basins
shall be sized to provide 3,600
ft3 of storage below the outlet
pipe per acre drained to the
basin. Alterative designs may be
used which provide storage
below the outlet for a calculated
volume of runoff from a 2-year,
24-hour storm and provides not
less than 1,800 ft3 of storage
below the outlet pipe from each
acre drained to the basin.
The 2003 permit states that a
sediment settling pond shall be
sized to provide at least 67 cubic
yards of storage per acre or 1 809
ft3/acre.
The 2002 general permit states
that for 10 or more acres drained
the basin shall provide storage
for a 2-year, 24-hour storm event
or 3,600 ft3 of storage per acre.
The 2005 permit states that (1) A
sediment storage zone of 1,000
ft3 per disturbed acre within the
watershed of the basin is
required; (2) A dewatering zone
of 5,000 ft3 for each acre
tributary to the basin is to be
provided. Reductions in the
dewatering zone are allowed
unless the basins is in a HQ or
Sediment basins notes/other
requirements
into the basin (1,800 ft3 is equivalent
to a 1/2 inch of sediment per acre of
basin drainage area) for a maximum
of 100 acres. See more details on
basin design provided in manual.
The 2006 Rainwater and Land
Development Manual states that for
areas less than 100 acres, the volume
of the dewatering zone shall be a
minimum of 1,800 ft3/acre of
drainage (66.7 yd3/acre).
Basin sizing of 3,600 ft3/acre.
Soil stabilization
Notes/other requirements
None
Stabilization in 7 days, or 2
days if near stream.
Apply temporary or
permanent soil stabilization
measures immediately on all
disturbed areas as grading
progresses.
None
Days
N/A
2 or 7
(see
notes)
14
1 (see
notes)
N/A
Numeric standard
No
No
No
No
No
Water quality
requirements
Other notes
Additional
requirements for
special waters.
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VO
State requirements: Environmental Protection Agency (EPA) 2007
State
Rhode Island
South Carolina
South Dakota
Tennessee
Sediment basin general
requirements
EV watershed, however the
minimum required dewatering
zone is at least 3,600 ftVacre.
No sizing criteria in permit.
Basin sizing requirements for 10
or more acres provide storage for
a 10-year, 24-hour storm event
or at least 3,600 fVVacre (10-year
24-hour Soil Conservation
Service (SCS) Type II, or Type
III (coastal zone) storm event).
Basin sizing of 3,600 ft3/acre.
The 2005 permit states to design
for a 2-year, 24-hour storm for
'
Sediment basins notes/other
requirements
The Stormwater Design and
Installation Standards Manual and the
Soil Erosion and Sediment Control
Handbook were not reviewed.
The 2002 Erosion and Sediment
Control Handbook states that the total
storage volume of the basin at the
spillway should be at least 134 cubic
yards (3,618 ft3) per acre of drainage
area. The volume of the permanent
pool must be at least 67 cubic yards
(1,809 ft3) per acre of drainage area
and the volume of dry storage must
be at least an additional 67 cubic
yards (1,809 ft3) per acre of drainage
area. The emergency spillway should
be able to handle a 2-year or 5-year,
24-hour storm event. The outlets for
the basin should pass the peak runoff
expected from the contributing
drainage area for a 25-year, 24-hour
storm.
Soil stabilization
Notes/other requirements
As soon as possible, but no
later than 14 days.
Preconstruction vegetative
ground cover shall not be
destroyed, removed or
disturbed more than 10 days
before grading or earth
moving unless the area is
seeded and/or mulched or
other temporary cover is
installed. Construction must
be phased for projects in
which more than 50 acres of
soil will be disturbed. No
more than 50 acres of active
soil disturbance is allowed at
any time during the
construction project.
Days
14
14
14
15
Numeric standard
No
80 percent of TSS removal for
drainage areas > 5 acres.
No
No
Water quality
requirements
Other notes
There are
additional SWPPP
requirements for
discharges into
impaired or high-
quality waters.
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State requirements: Environmental Protection Agency (EPA) 2007
State
Texas
Utah
Vermont
Virginia
Sediment basin general
requirements
The 2003 Permit states that
sediment basins are required
where feasible for common
drainage locations that serve an
area with 10 or more acres
disturbed at one time. The
temporary (or permanent)
sediment basin should provide
storage for a calculated volume
of runoff from a 2-year, 24-hour
storm from each disturbed acre
drained. Where rainfall data is
not available or a calculation
cannot be performed, a sediment
basin providing 3,600 ft3 of
storage per acre drained is
required where attainable until
final stabilization of the site.
The 2002 permit says for 10 or
more acres basin storage shall
provide for a 10-year, 24-hour
storm event, or 3,600 ft3/acre.
No sizing criteria in permit.
For common drainage locations
that serve an area with 3 or more
acres disturbed at one time, a
temporary (or permanent)
sediment basin providing 3,618
ft3 of storage per acre drained, or
equivalent control measures,
shall be provided where
attainable until final stabilization
of the site.
Sediment basins notes/other
requirements
Basin sizing of 3,600 ft3/acre for
moderate risk only.
The Virginia Erosion and Sediment
Control regulations state that
sediment traps and sediment basins
shall be designed and constructed
based on the total drainage area to be
served by the trap or basin. The
minimum storage capacity of a
sediment trap shall be 134 cubic
yards per acre of drainage area (3,618
ft3) and the trap shall only control
drainage areas less than 3 acres.
Surface runoff from disturbed areas
that is composed of flow from
drainage areas greater than or equal to
three acres shall be controlled by a
sediment basin. The minimum
storage capacity of a sediment basin
shall be 134 cubic yards per acre of
drainage area. The outfall system
shall, at a minimum, maintain the
Soil stabilization
Notes/other requirements
For low or moderate risk
activities only.
Days
14
14
21 (see
notes)
7
Numeric standard
For Concrete Batch plants
only.
No
No
No
Water quality
requirements
Other notes
Additional
requirements for
different locations
in Texas.
-------
>
State requirements: Environmental Protection Agency (EPA) 2007
State
Washington
Washington,
Small Parcel
West Virginia
Wisconsin
Sediment basin general
requirements
The 2002 permit states that
sediment basins and traps will be
installed with 3,600 ft3 of
storage, measured from the
bottom elevation of the structure
to the top of the riser or weir, per
acre of drainage and will have
draw down times of 48 to 72
hours. For locations on a site that
have a drainage area of 5 acres
or less, a sediment trap which
provides a storage volume equal
to 3,600 ft3/acre of drainage area
shall be installed. Half of the
volume of the trap will be in a
permanent pool and half will be
dry storage.
Sediment basins notes/other
requirements
structural integrity of the basin during
a 25-year, 24-hour duration storm
event. Runoff coefficients used in
runoff calculations shall correspond
to a bare earth condition or those
conditions expected to exist while the
sediment basin is used.
Basin requirements are different for
western and eastern parts of state
see manuals.
The Technical Standards document
states that basins shall be used for
greater than 5 to 100 acres. The sizing
criteria for determining treatment
surface area of a sediment basin are
based on the soil texture and peak
Soil stabilization
Notes/other requirements
Varies by time of year and
location in state. West of the
Cascade Mountains Crest:
During the dry season (May
1-Sept. 30): 7 days; during
the wet season (October 1
April 30): 2 days.
Not specified.
Days
2 or 7
(see
notes)
7
N/A
Numeric standard
The Water Quality Standards
for Surface Waters of the State
of Washington W AC 173-
201A-030 (1) (vi) states that
turbidity shall not exceed 5
NTU over background
turbidity when the background
turbidity is 50 NTU or less, or
has more than a 10 percent
increase in turbidity when the
background turbidity is more
than 50 NTU.
No
The current standard in
Wisconsin (NR 151.11 pg
409) requires construction
sites to implement erosion and
sediment controls to reduce to
the maximum extent
Water quality
requirements
Other notes
-------
to
State requirements: Environmental Protection Agency (EPA) 2007
State
Wyoming
Puerto Rico
District of
Columbia
Sediment basin general
requirements
No sizing criteria in permit.
Basin sizing for 2-year, 24-hour
storm or 3,600 ft3/acre.
Sediment basins notes/other
requirements
outflow during the 1-year, 24-hour
design storm. The overflow spillway
should be designed to carry the peak
rate of runoff expected from a 10-
year, 24-hour design storm.
The 1999 Urban Best Management
Practice (BMP) manual says use
basins for 5 to 100 acres.
Sediment basin requirements for
drainage areas of 10 or more acres.
Soil stabilization
Notes/other requirements
Temporary stabilization (such
as cover crop plantings,
mulching or erosion controls
blankets, surface roughening,
etc.) for exposed soil areas
where activities have
permanently or temporarily
ceased should be installed
whenever practicable in areas
where further work is not
expected for 28 days or more.
Days
28 (see
notes)
14
Numeric standard
practicable 80 percent of the
sediment load carried in runoff
on an annual basis, compared
to a baseline of no sediment or
erosion controls.
Wyoming water quality
regulations (Section 23, Page
1-20) require that discharge of
substances attributable to or
influenced by the activities of
man shall not be present in
quantities which would result
in a turbidity increase for cold
water fisheries and drinking
water supplies (classes 1,
2AB, 2A, and 2B), shall not
result in a turbidity increase of
more than ten (10)
nephelometric turbidity units
(NTUs). In all warm water or
nongame fisheries (classes 1,
2AB, 2B and 2C), the
discharge of substances
attributable to or influenced by
the activities of man shall not
be present in quantities which
would result in a turbidity
increase of more than 1 5
NTUs. An exception to shall
apply to the North Platte River
from Guernsey Dam to the
Nebraska line during the
annual silt run from Guernsey
Dam.
No
Water quality
requirements
For parking lots, city
streets, and high-speed
roads, the runoff depth to
be treated for post-
development land use is
0.5 inch. For rooftops,
sidewalks, pedestrian
plaza areas, the runoff
depth is 0.3 inch
Other notes
There are two
general permits
one for small and
one for large.
-------
State requirements: 2004 Technical Development Document (TDD) Section 7
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Florida , DEP, Northern District
(only applies in NW Florida)
Florida, South Florida Water
Management District (General,
Standard General, Noticed General
and Individual Permits)
Florida, Southwest Florida Water
Management District
Florida, St. Johns River Water
Management District
Florida, Suwannee River Water
Management District
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Sediment basin storage volumes
(ft3/acre drained)
3,600
3,600
3,600
3,600
3,600
1,800
1,800
3,600
3,600
1,800
1,800
3,600
1,800
1,800
3,600
3,600
Sediment basin requirements for
drainage areas >_10 acres
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
No
No
Yes
No
No
Yes
Yes
Seeding requirements 14 days post-
construction
No
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
-------
State requirements: 2004 Technical Development Document (TDD) Section 7
State
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Sediment basin storage volumes
(ft3/acre drained)
3,600
3,600
3,600
1,800
3,600
3,600
3,600
3,600
1,800
1,800
1,800
3,600
3,600
1,800
3,600
3,600
3,600
1,800
1,800
3,600
1,800
3,600
1,800
3,600
3,600
3,600
3,600
Sediment basin requirements for
drainage areas >_10 acres
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
No
No
No
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Seeding requirements 14 days post-
construction
Yes
No
Yes
No
Yes
No
No
No
No
No
No
Yes
Yes
No
Yes
Yes
No
No
Yes
Yes
No
No
No
Yes
Yes
Yes
Yes
-------
State requirements: 2004 Technical Development Document (TDD) Section 7
State
Utah
Vermont
Virginia
Washington
Washington, Small Parcel
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
Sediment basin storage volumes
(ft3/acre drained)
3,600
1,800
3,600
1,800
3,600
1,800
1,800
3,600
Sediment basin requirements for
drainage areas >_10 acres
Yes
No
Yes
No
Yes
No
No
Yes
Seeding requirements 14 days post-
construction
Yes
No
Yes
No
Yes
No
No
Yes
-------
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Numeric standard or
pollutant reduction
requirements
Turbidity < 50 NTU.
Total Suspended Solids
greater than 20 microns.
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
2 year/6 hour
10 year/24 hour
2 year/24 hour
Maximum allowed
denuded acreage or
soil stabilization
requirement
Notes
An inspector must be qualified personnel provided
by the discharger.
Developers must submit erosion and sediment
control plan and SWPPP before filing a notice of
intent. Sites greater than or equal to 10 acres must
implement a temporary or permanent sediment
basin. Sites less than 10 acres must implement
sediment traps and silt fences.
Inspections will be performed before anticipated
storm events, during extended storm events, and
after storm events, and at least once each 24-hour
period during extended storm events to identify
BMP effectiveness and implement repairs or design
changes as soon as feasible depending on field
conditions. A discharger is also responsible for
inspecting and cleaning all public and private roads
for sediment. Construction activities that fall under
the jurisdiction of the California Department of
Transportation (CALTRANS) have separate a
permit and regulations.
Stormwater management plan must be submitted to
state for a 10-day review, as well as be retained on
site. PG determined: A certification verifying that
the Stormwater Management Plan (SWMP) is
complete must be submitted to state 10 days before
beginning construction activities, as well as being
retained on site during construction activities. The
SWMP shall be prepared in accordance with good
-------
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Connecticut
Delaware
Florida
Florida , DEP, Northern
District (only applies in
NW Florida)
Florida, South Florida
Water Management
District (General,
Standard General, Noticed
General and Individual
Permits)
Florida, Southwest
Florida Water
Management District
Florida, St. Johns River
Water Management
District
Florida, Suwannee River
Water Management
District
Georgia
Hawaii
Numeric standard or
pollutant reduction
requirements
80 percent TSS reduction.
80 percent TSS reduction.
80 percent TSS reduction.
Turbidity less than 29
NTU.
80 percent TSS reduction.
Turbidity less than 10 to
25 NTUs.
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
0.5 inch
0.5 inch
1 inch
0.5 inch
1 inch
25 year/24 hour
Maximum allowed
denuded acreage or
soil stabilization
requirement
Notes
engineering, hydrologic and pollution control
practices.
*> 100 acres, 1 inch rainfall; < 100 acres, 0.5 inch
rainfall
Turbidity < 25 NTUs for waters supporting warm
water fisheries, or <10 NTUs for waters classified as
trout waters.
Construction shall be phased for large projects; one
phase must be stabilized before another can begin.
A 50-day maximum from removal of pre-
construction conditions to temporary stabilization.
-------
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Numeric standard or
pollutant reduction
requirements
80 percent TSS reduction.
Goal of 80 percent TSS
reduction (compared to
pre-construction levels).
40 to 80 percent TSS
reduction
80 percent TSS reduction
based on the average
annual TSS loading from
all storm events less than
or equal to the 2-year/24-
hour storm.
80 percent TSS reduction
Settleable Solids < 0.5 to
2.5 ml/L per hour.
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
3,600 ft3/acre
2 year
2 year/24 hour
2 year/24 hour
3,600 ft3/acre
0.5 inch
2 year/24 hour
Maximum allowed
denuded acreage or
soil stabilization
requirement
Notes
Sites greater than 10 acres require an on-site
temporary sediment basin.
Settleable solids less than 2.5 ml/L per hour for
normal land disturbance, and 0.5 ml/L per hour for
land disturbance within sensitive areas.
Dischargers must submit with the state application
form a stormwater erosion control plan (SWECP)
that resembles EPA's construction site SWPPP.
Permit coverage begins only when Montana
-------
VO
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Numeric standard or
pollutant reduction
requirements
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
0.5 inch
Maximum allowed
denuded acreage or
soil stabilization
requirement
20 acres of total
disturbance at any
given time for areas
discharging to high-
quality waters.
Notes
Department of Environmental Quality reviews and
approves the SWECP. Inspections must also be
conducted everyday during prolonged precipitation
or snowmelt periods. A registered Professional
Engineer must prepare the SWESCP if the site is
greater than 20 acres. Also regulate down to 1 acre
if the construction site is within 100 feet of a surface
waterbody. Montana has a sediment and erosion
control guidance manual that lists standard use
BMPs. If other BMPs are used, they need to be
submitted with SWECP to the state for approval.
For slopes steeper than 3 : 1 and greater than 5
vertical feet, surface roughening is required. Filter
fences should be used on drainage areas >1 acre;
sediment traps should be used only on drainage
areas > 3 acres; and temporary sediment ponds
should be used only on drainage areas > 10 acres.
-------
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Numeric standard or
pollutant reduction
requirements
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
Maximum allowed
denuded acreage or
soil stabilization
requirement
Notes
Oklahoma
3,600 ft3/acre
A vegetated buffer zone of at least 100 feet must be
retained or successfully established between the area
disturbed during construction and all perennial or
intermittent streams on or adjacent to the
construction site. A vegetated buffer zone at least 50
feet wide must be retained or established between
the area disturbed during construction and all
ephemeral streams or drainages. Treatment volume
is the lesser of 3,600 ft3 or the runoff volume of a 2-
year, 24-hour storm.
Oregon
If the site is greater than 20 acres, an erosion and
sediment control plan must be prepared by a
Professional Engineer, or Registered Landscape
Architect, or Certified Professional in Erosion and
Sediment Control, and the plan must be submitted
90 days before construction begins. All permittees
must submit an Oregon Land Use Compatibility
Statement if they do not already have one on file
with Oregon Department of Environmental Quality.
Pennsylvania
5 year
Basins volumes should drain no quicker than 4 days
and no longer than 7 days.
Rhode Island
80 to 90 percent TSS
reduction.
10 year
South Carolina
80 percent TSS reduction.
3,600 ft7acre
Sediment trapping efficiency is a performance-
based requirement for any BMPs. The major
requirements for stormwater control plans are
application, location map, type and location of
BMPs, construction sequencing, location of
disturbed areas, property line and waters of the state,
standard notes, grassing specifications. The
minimum required volume for water quality
management is 3,600 ft3 for a disturbed area of more
-------
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Numeric standard or
pollutant reduction
requirements
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
Maximum allowed
denuded acreage or
soil stabilization
requirement
Notes
than 10 acres. If there is not a sediment basin of
3,600 ft3 and the drainage area is less than 10 acres,
sediment traps, silt fences, or equivalent measures
are needed for sideslope and downslope boundaries
for the construction area. However, the first 0.5 inch
rainfall runoff in a 24-hour period is applicable to
the coastal counties only.
South Dakota
5 year
Tennessee
The permittee shall maintain records of all
inspection and maintenance.
Texas
3,600 ff/acre
>
Utah
1 inch or 24-hour storm
event
Where sites have been finally or temporarily
stabilized, or when runoff is unlikely because of
winter conditions or during seasonal arid periods in
arid areas and semiarid areas inspections shall be
conducted at least once every 30 days. Runoff
volume from a 10-year, 24-hour storm event for 10
or more disturbed acres shall be evaluated for water
quality. For areas less than 10 acres or where
calculations for the volume of runoff for disturbed
acres is not performed, a sediment basin providing
3,600 ft3 of storage per acre drained or equivalent
control measures shall be provided. (1) Where the
initiation of stabilization measures by the 14th day
after construction activity has temporary or
permanently ceased is precluded by snow cover or
frozen ground conditions, stabilization measures
shall be initiated as soon as possible. (2) In arid
areas, semiarid areas, and areas experiencing
droughts where the initiation stabilization measures
by the 14th day after construction activity has
temporarily or permanently ceased is precluded by
-------
to
State Requirements: 2002 Technical Development Document (TDD) Appendix A
State
Vermont
Virginia
Washington, Large Parcel
Washington, Small Parcel
West Virginia
Wisconsin
Wyoming
Puerto Rico
District of Columbia
Numeric standard or
pollutant reduction
requirements
Turbidity less than 10 to
15 NTUs.
Minimum depth of
runoff or storm return
frequency to treat for
water quality
management (per acre)
3,600 ft3/acre
24 hour/6 month
24 hour/6 month
2 year
Maximum allowed
denuded acreage or
soil stabilization
requirement
2 days between
October 1 and April
30 (i.e., the wet
season); 7 days
between May 1 to
September 30 (dry
season)
2 days between
October 1 and April
30 (i.e., the wet
season); 7 days
between May 1 to
September 30 (dry
season)
Notes
seasonal arid conditions, stabilization measures shall
be initiated as soon as practicable.
Sediment basins required for sites of 10 acres or
more (except those with final stabilization); for sites
less than 10 acres, the same units are required but
only for sideslope and downslope boundaries of
construction sites.
-------
Appendix B
Literature Search Annotated Bibliography
-------
-------
Appendix B: Literature Search Annotated Bibliography
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Comments:
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Peter T. Weiss,1 John S. Gulliver,2 and Andrew J. Erickson3
2007
Cost and Pollutant Removal of Storm-Water Treatment Practices
1 Valparaiso University
2'3 University of Minnesota
Journal of Water Resources Planning and Management
Volume 133, Issue 3, pp. 218-2229 (May/June 2007)
Six storm-water best management practices (BMPs) for treating urban rainwater
runoff were evaluated for cost and effectiveness in removing suspended
sediments and total phosphorus. Construction and annual operating and
maintenance (O and M) cost data were collected and analyzed for dry extended
detention basins, wet basins, sand filters, constructed wetlands, bioretention
filters, and infiltration trenches using literature that reported on existing storm-
water BMP sites across the United States. After statistical analysis on historical
values of inflation and bond yields, the annual O and M costs were converted to
a present worth based on a 20-year life and added to the construction cost. The
total present cost of each storm-water BMP with the 67% confidence interval
was reported as a function of water quality design volume, again with a 67%
confidence interval. Finally, the mass of TSS and total phosphorus removed
over the 20-year life was estimated as a function of the water quality volume.
For the six storm-water BMPs investigated, results show that, ignoring land
costs, constructed wetlands have been the least expensive to construct and
maintain if appropriate land is available. However, since wetlands typically
require more land area to be effective, land acquisition costs may result in
wetlands being significantly more expensive than other storm-water BMPs that
require less area. The results can be used by planners and designers to estimate
both the total cost of installing a storm-water BMP and the corresponding total
suspended solids and total phosphorus removal
Summarizes recent cost work and presents best fit curves and 67 percent
confidence intervals as ranges. The presentation of total capital costs assumes
construction costs plus the present worth of 20 years of operating and
maintenance costs. Paper was reviewed as part of EPA's review of costs for
permanent sedimentation ponds and sand filters.
It also summarizes removal efficiencies for TSS and Phosphorus by BMP.
P. Kaini, K. Artita, and J. W. Nicklow
2007
Evaluating Optimal Detention Pond Locations at a Watershed Scale
Department of Civil and Environmental Engineering, Southern Illinois
University
World Environmental and Water Resources Congress 2007
Structural BMPs like stormwater basins (detention and retention basins),
wetlands, filter strips and grassland swales are extensively used as stormwater
runoff controls. BMPs are often designed for peak flow reduction or pollution
B-l
-------
Appendix B: Literature Search Annotated Bibliography
control or can be considered for dual purpose in that they provide both water
quality and quantity benefits by relying upon storage allocation and key
mechanisms of setting filtration, sorption, biodegradation and
evapotranspiration. In spite of previous studies, there exists neither a
methodology nor a generalized model for selecting, placing, and sizing BMP
combinations that cost-effectively promotes achievement of treatment goals at
larger spatial scales. This paper presents part of an ongoing research effort to
develop a new, comprehensive decision support tool for watershed-scale BMP
design. The current model is designed to identify detention pond sizes that best
achieve target peak flow reduction criteria. It is developed by coupling the
U.S. Department of Agriculture's (USDA) Soil and Water Assessment Tool
(SWAT) and a genetic algorithm. The model is applied to Silver Creek
watershed, a subbasin of the larger Lower Kaskaskia watershed in Illinois. The
results show that detention ponds can be designed at a holistic, watershed scale
to more effectively achieve peak flow reduction goals. Future work will focus
on expansion of the model, which will also be disseminated through outreach
workshops in portions of Illinois and surrounding states.
Comments: Basin-wide design does not yet appear to be a viable option. The paper notes,
"Despite these efforts [previous studies], there exists neither a methodology
nor a generalized model for selecting, placing, and sizing BMP combinations
that cost effectively promote achievement of treatment goals at the watershed
scale. This paper presents ongoing research to develop a new, comprehensive
decision support tool for watershed-scale BMP design."
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Fu-hsiung Lai, Jenny Zhen, John Riverson, and Leslie Shoemaker
2006
SUSTAINAn Evaluation and Cost-Optimization Tool for Placement of
BMPs
Tetra Tech, Fairfax, VA
World Environmental and Water Resources Congress 2006
To assist stormwater management professionals in planning for best
management practices (BMPs) implementation, the U.S. Environmental
Protection Agency (USEPA) is developing a decision-support system for
placement of BMPs at strategic locations in urban watersheds. This tool will
help develop, evaluate, select, and place BMP options based on cost and
effectiveness. The system was formerly called the Integrated Stormwater
Management Decision Support Framework (ISMDSF), but will be tentatively
called the System for Urban Stormwater Treatment and Analysis INtegration
(SUSTAIN). SUSTAIN, a generic public domain framework, will provide a
means for objective analysis of management alternatives among multiple
interacting and competing factors. The desired outcome from the system
application is a thorough, practical, and informative assessment considering
economic, environmental, and engineering factors. SUSTAIN has seven key
components: framework manager, ArcGIS interface, watershed model, BMP
B-2
-------
Appendix B: Literature Search Annotated Bibliography
model, optimization model, post-processor, and Microsoft Access database.
They are integrated under a common ArcGIS platform. SUSTAIN supports
evaluation of BMP placement at multiple scales from a few city blocks to
large watersheds.
Comments: Basin-wide design does not yet appear to be a viable option. EPA is
developing a decision-support system for placement of BMPs at strategic
locations in urban watersheds. This tool will help develop, evaluate, select,
and place BMP options on the basis of cost and effectiveness.
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Comments:
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Yuan Cheng, Ph.D., P.E.
2006
Extended Analysis for Sediment Pond Design
Benatec Associates, Inc.
World Environmental and Water Resources Congress 2006
An example of extended analysis for sediment pond design is presented. The
sediment pond is designed to trap the suspended sediment carried by surface
runoff from a construction site. Extended analysis can show dynamic changes
of the velocity field in a pond as well as suspended sediment distribution from
the pond inlet to the outlet. Results from the analysis can be used by designers
to adjust pond size and shape for more effective reduction of sediment
discharge that varies with time at the pond outlet.
Presents site-specific two-dimensional finite analysis approach for designing
pond shape and size.
Michael E. Barrett
2003
Performance, Cost, and Maintenance Requirements of Austin Sand
Filters
Center for Research in Water Resources, University of Texas, Austin, TX
Journal of Water Resources Planning and Management
Volume 129, Issue 3, pp. 234-242 (May/June 2003)
Five Austin-style sand filters were constructed by the California Department
of Transportation (Caltrans) as retrofit projects for maintenance yards and
park-and-ride facilities in the Los Angeles and San Diego metropolitan areas.
Each of these filter systems included storm-water monitoring equipment for
collection of flow weighted composite samples. In addition, detailed records
were compiled of the design elements, construction costs, and type and
amount of maintenance required at each of the sites. The construction costs
were relatively high because of the retrofit nature of the project and the
integration of the Caltrans storm-drain system with those of the adjoining
metropolitan areas, which eliminated any opportunities for economies of scale.
An analysis of performance using linear-regression techniques indicated that
for sediment and almost all particle associated constituents, effluent
concentration was independent of influent concentration. For instance, the
-------
Appendix B: Literature Search Annotated Bibliography
average suspended solids concentration in treated runoff was 7.8±1.2 mg/L (at
the 90% confidence level) regardless of observed influent concentration. The
constant effluent quality produced for the particulate constituents indicates that
the calculation of a percent reduction is more indicative of the influent
concentration rather than the performance of the filter itself. Rejuvenation of
the filter bed was required at three sites after 3 years of operation when the
solids loading to the system was between 5 and 7.5 kg/m2 of filter area.
However, the clogging may have been accelerated by problems with the
pumps that resulted in standing water on the filter for extended periods. Other
maintenance activities consisted mainly of inspections, pump repair, and
activities to reduce mosquito breeding. The main impediment to widespread
implementation is the initial construction cost; however, modifications of the
filter configuration and media may reduce these costs and increase
effectiveness, thereby making the technology more attractive.
Comments: Warrants further review if EPA evaluates use of sand filtration in meeting
numerical standards. The article notes that it is difficult to determine the
validity of the 1993 construction costs ("Guidance specifying management
measures for sources of nonpoint pollution in coastal waters"). Note that the
any use of the costs and removals from this study would need to consider that
the site selection in this study was limited to relatively small, impervious
watersheds. "The most important consideration was the extent to which runoff
from unstabilized areas would be able to enter the filter. The biggest threat to
the long-term successful operation of any filter is the introduction of excessive
amounts of sediment that cause premature clogging of the filter media. For this
reason, site selection was limited to relatively small, impervious watersheds
(park-and-ride areas and maintenance stations)."
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
R. M. Hozalski, A. Erickson, and J. S. Gulliver
2007
A New Approach for Assessing the Performance of Stormwater Best
Management Practices
University of Minnesota, Department of Civil Engineering
Proceedings of the World Environmental and Water Resources Congress
2007
One approach for improving the quality of Stormwater runoff before it enters
the receiving water is to install Stormwater BMPs. Stormwater BMPs include a
wide range of systems (rain gardens, ponds, wetlands, underground
proprietary sediment removal devices, etc.) used to reduce Stormwater runoff
quantity or improve Stormwater quality, or both. No standard methodology for
assessment of Stormwater BMPs is available. Therefore, we propose a tiered
approach to Stormwater BMP assessment that is termed the "Four levels of
assessment" (Table 1), that are numbered in order of increasing difficulty
and cost. Developers of an assessment program should consider each of four
levels of assessment in order, and consider advancing to next level only when
requirements of the assessment program have not been satisfied. All
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Appendix B: Literature Search Annotated Bibliography
stormwater BMP assessment programs should include regularly scheduled (at
least annual) visual inspections (level 1). In addition to visual inspections,
capacity testing (level 2) and/or simulated runoff testing (level 3), if
warranted, should be included in stormwater BMP assessment programs at
regular intervals to determine the performance of a BMP immediately after
installation and to determine how performance of a stormwater BMP is
changing with respect to time, changes in the watershed, or both. If the goals
of the assessment program cannot be met by capacity testing or simulated
runoff testing, or these techniques are not feasible, then monitoring (level 4)
should be implemented as part of the assessment program.
Comments: Describes performance assessment of BMPs through visual inspections,
capacity testing, simulated runoff testing, and/or monitoring.
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Comments:
J. M. Hathaway, W.F. Hunt, R.A. Smith, and K.L. Bass
2007
Innovative Stormwater Treatment Practices in the Neuse and Tar-
Pamlico Basins
North Carolina State University, Biological and Agricultural Engineering
Department
Proceedings of the World Environmental and Water Resources Congress
2007
Urbanization within North Carolina's watersheds and the need for proactive
mitigation led to the establishment of the North Carolina Ecosystem
Enhancement Program (EEP) in July 2003. The EEP is responsible for the
majority of mitigation efforts throughout the state. These efforts include the
restoration, enhancement, and preservation of streams and wetlands, as well as
the creation of stormwater best management practices (BMPs) for the purpose
of maintaining and improving water quality and riparian habitats across the
state.
This project involves a partnership between EEP and the Biological and
Agricultural Engineering Department (B AE) at North Carolina State
University for the purpose of locating, designing, and monitoring stormwater
BMPs. In addition, local governments and the North Carolina Cooperative
Extension Service assist in project site selection and development.
Two large river basins in North Carolina, Neuse and Tar-Pamlico, have
historic, significant degradation to water quality partially due to urbanization
and agricultural practices. Primary pollutants within these basins include
nitrogen and phosphorous. To change the trend of degradation, the State of
North Carolina enacted regulations for nitrogen and phosphorous removal
specifically for these basins. These regulations provided for the funding of the
EEP Nutrient Reduction Program by authorizing impact fees.
Provides "an example of how academic institutions and state governments can
work together to develop programs to identify design, and build retrofit
stormwater BMPs."
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Appendix B: Literature Search Annotated Bibliography
Author(s):
Date:
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Organization:
Source:
Abstract:
Kelly A. Collins, William F. Hunt, and Jon M. Hathaway
2007
Evaluation of Various Types of Permeable Pavements with Respect to
Water Quality Improvement and Flood Control
North Carolina State University, Biological and Agricultural Engineering
Department
Proceedings of the World Environmental and Water Resources Congress
2007
In many U.S. states, different permeable pavement types are considered to
have the same capabilities in reducing runoff, and they are not credited with
improving water quality. To test various permeable pavement designs, a
parking lot consisting of four different types of permeable pavements and
standard asphalt was constructed in Kinston, NC. The permeable pavement
sections consist of pervious concrete (PC), permeable interlocking concrete
pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, and
concrete grid pavers (CGP), each covering a 1200 sq. ft. area with a 10 in.
gravel storage layer. The purpose of this study is to evaluate and compare the
effects of each pavement type on water quality and runoff reduction. Site
analyses on every rainfall event began in March, 2006, and will continue
through March, 2007. Preliminary results indicate significant (p<0.05) peak
flow and volume reductions from all permeable pavements. Additionally, there
has been little to no runoff observed from any of the pervious sections.
Pollutant removal performance by the pavements has widely varied. As a
result of this study, it is expected that the state of North Carolina will make a
judgment on how much pollutant removal credit permeable pavement types
should receive. Also, this study may be used to determine whether or not
stormwater credit should vary based on pavement type.
Comments: Evaluates parking lot runoff from various permeable pavement designs.
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Ben Urbonas,1 and Jim Wulliman2
2007
Stormwater Runoff Control Using Full Spectrum Detention
1 Urban Drainage and Flood Control District, Denver, CO
2 Muller Engineering Company, Lakewood, CO
Proceedings of the World Environmental and Water Resources Congress
2007
The goal of controlling peak flow rates at individual sites to pre-developed
levels can be met using detention basins for design storms from 2- to 100-year
return periods. However control of peak storm runoff flows along receiving
streams by multiple detention basins operating simultaneously within larger
urban catchments are much more difficult to achieve. The latter topic was
studied in the past by several investigators, but the findings were very limited
in scope and were focused primarily on larger runoff events such as the 10-
year to 100-year flows. At the same time, there is evidence that stream
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Appendix B: Literature Search Annotated Bibliography
geometry, water quality and aquatic habitat are impacted significantly whether
this type of detention is used, or not, as areas urbanize. The profound
hydrologic and geomorphic changes caused by urbanization require more
robust control of the frequently occurring, smaller, runoff events. In response
to this, different approaches toward designing stormwater detention were
investigated and modeled by the authors. This testing was first done using
design storm protocols employed by the Urban Drainage & Flood Control
District for the Denver area of Colorado and then followed up using the
USEPA SWMM 5.0 model calibrated to 15-years of recorded 5-minute
rainfall (5 gages) and runoff (2 gages) data for a 3.1 square mile watershed.
This paper presents the findings most applicable for the Denver region and
other locations having similar precipitation patterns; however, the underlying
principles used to develop this concept can be used to develop design
protocols for other hydrologic regions of the USA and other countries.
Comments: Describes a watershed-wide approach for minimizing the excess urban runoff
volume (difference between urban and pre-development), including smaller
rain events such as the 2-year storm.
Author(s):
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Dianna M. Hogan1'2 and Mark Walbridge3
2007
Best Management Practices for Nutrient and Sediment Retention in
Urban Stormwater Runoff
Department of Environmental Science and Policy, George Mason University,
Fairfax, VA
2Eastern Geographic Science Center, U.S. Geological Survey, Reston, VA
3Department of Biology, West Virginia University, Morgantown, WV
Journal of Environmental Quality
Stormwater management infrastructure is utilized in urban areas to alleviate
flooding caused by decreased landscape permeability from increased
impervious surface cover (ISC) construction. In this study, we examined two
types of stormwater detention basins, SDB-BMPs (stormwater detention
basin-best management practice), and SDB-FCs (stormwater detention basin-
flood control). Both are constructed to retain peak stormwater flows for flood
mitigation. However, the SDB-BMPs are also designed using basin
topography and wetland vegetation to provide water quality improvement
(nutrient and sediment removal and retention). The objective of this study was
to compare SDB (both SDB-BMP and SDB-FC) surface soil P concentrations,
P saturation, and Fe chemistry with natural riparian wetlands (RWs), using
sites in Fairfax County, Virginia as a model system.
Study compares nutrient and sediment retention in urban stormwater runoff for
stormwater detention basin BMPs and stormwater detention basin flood
control.
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Appendix B: Literature Search Annotated Bibliography
Author(s):
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Comments:
Arvind Narayanan and Robert Pitt
2006
Cost of Urban Stormwater Control Practices
University of Alabama
This report is a consolidated and summary of information obtained from the
following major reports on costs of Stormwater controls, plus additional
specialized references:
Costs of Urban Nonpoint Source Water Pollution Control Measures
prepared by Southeastern Wisconsin Regional Planning Commission
1991
Costs of Urban Stormwater Control by Heaney, Sample, and Wright for
USEPA 2002
BMP Retrofit Pilot Program prepared by CALTRANS 2001
This research presents a method to determine the costs of several types of
Stormwater control practices including the costs of conventional drainage
system. Several published literature sources were reviewed that contained
costs of control practices. Standard unit cost data used in developing the
conventional conveyance drainage system costs were obtained from RS
Means. The cost data were transformed into equations and utilized to develop
the cost module for the Source Loading and Management Model
WinSLAMM). An Excel spreadsheet model was also developed to estimate
the costs of conventional Stormwater drainage systems based on the published
unit cost data. In an example, the costs estimated by the spreadsheet model
were compared to the costs associated with the Stormwater control practices as
estimated by WinSLAMM for a 250-acre industrial site in Huntsville, AL. The
costs of site biofiltration, large-scale grass swales, and a wet detention pond
were compared to the costs for the conventional drainage system. The cost
information available from published literature sources and other references
were in the form of tables and equations. The cost information gathered
provided regional cost estimates for the control practices for a specific year.
Cost indices published by the Engineering News Record were used to estimate
the present costs from historical cost information and at locations where cost
information is unavailable. These cost indices, from 1978 to 2005, were
incorporated into WinSLAMM and the spreadsheet model. Based on the cost
data obtained form Southeastern Wisconsin Regional Planning Commission
(1991), the component(s) that affected the control practice cost the most were
also analyzed
References previously used documents for sedimentation basins (1976 EPA,
Cost Estimating ManualCombined Sewer Overflow Storage and Treatment,
referenced in subsequent EPA documents (1993 and 1999)) and detention
ponds (Young et al. 1996, the out-of-date 1986 equations referenced in
Schueler 2000).
Sand filter information references CALTRANS 2004, which was included in
EPA's review of sand filters.
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Appendix B: Literature Search Annotated Bibliography
Author(s):
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Author(s):
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Comments:
Dennis Jurrie, P.E.
Unknown
Flocculation of Construction Site Runoff in Oregon
Sisul Engineering
Unknown
Describes flocculation for treating stormwater runoff from construction sites.
Includes sampling results for Sumalchlor 50 (a Polyaluminum Chloride) at a
corporate park construction site in Oregon. Provides a cost to treat and
flocculate stormwater runoff of $0.08 per gallon of water treated. Warrants
additional review as part of the evaluation of numerical standards.
Eric Woodhouse and Tiffany Leop
2007
Temporary Slope Protection: Cost Versus Effectiveness
Landscape Development, Inc.
StormCon 2007
Landscape Development, Inc., conducted a study in Santa Clarita, CA. Eight
products and applications were tested on 1000 square foot, 2:1 slope panels
during the heavy rain season of 2004-2005. The rains in this area accumulated
to over 40 inches between October and May. The products and applications
tested include straw blanket, blown straw with organic binder-tackifier,
straw/coco blanket, coconut blanket, jute netting, wood fiber mulch and
organic binder, a preblended stabilized fiber matrix (SFM) with two stabilizer
components (a tackifier and cross link binder), and another stabilized fiber
matrix (SFM) with one stabilizing component consisting of wood fiber mulch
with polyacrylimide stabilizer. Four soil loss samples were taken over the
course of the study. The weight of the soil lost was accumulated and used in
comparing the performance of the varying products and applications. The
blanket products performed better, overall, for retaining the soil on the slope
face when compared for amount of soil lost per inch of rainfall. The cost
comparison for all the products and applications showed comparable pricing
when extended over the duration of the product/application's effective lifeline.
Cost comparisons for the various applications in regards to lifespan and price
per square foot are presented in this paper.
Provides a comparison of soil loss, price per square foot, and lifespan for
various erosion controls (straw blanket, blown straw with organic binder-
tackifier, straw/coco blanket, coconut blanket, jute netting, wood fiber mulch
and organic binder, a preblended stabilized fiber matrix (SFM) with two
stabilizer components (a tackifier and cross link binder), and another stabilized
fiber matrix (SFM) with one stabilizing component consisting of wood fiber
mulch with polyacrylimide stabilizer). The study notes, "It can be seen that
cost is directly correlated with the lifespan of the application as well as the
effectiveness in minimizing soil loss." The article might be useful for
inclusion in the updated technical development document.
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Appendix B: Literature Search Annotated Bibliography
Author(s):
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Organization:
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Comments:
Author(s):
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Organization:
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David Wachal
2007
BMP Selection for Land Disturbance: A Methodology Based on
Efficiency, Cost, and Site Management Goals
City of Dention, Texas
StormCon 2007
This paper presents a methodology for developing a BMP selection tool for
disturbed hillslopes based on BMP efficiency, BMP implementation costs, and
site management goals. To demonstrate how the methodology was developed
and applied, a case study focusing on Natural Gas Exploration and Production
(NGE&P) sites is presented. Version 2 of the Revised Universal Soil Loss
Equation (RUSLE2) was used to evaluate sediment yields for several
combinations of BMPs, slopes, and soil types, and based on the modeling
results, BMP efficiency values were computed for each possible combination.
Efficiency values for the various slope and soil combinations revealed that
both slope and soil type influences the effectiveness of the BMPs. The
efficiency values were incorporated into a selection tool that also included
estimated BMP implementation costs. While this paper focuses on NGE&P
sites, the methodology presented is easily adaptable to other types of disturbed
site conditions.
Project evaluated BMP efficiencies and costs for BMPs (seeding, mulching,
erosion blanket, silt fence, and vegetated filter strip) and BMP combinations
for disturbed hillsides in Natural Gas Exploration and Production. The method
uses RUSLE2 (for possible combinations of three soil types and three slope
profiles) as an erosion prediction tool. The methodology then uses the Best
Management Practices Assessment Tool (BMPSAT) to evaluate efficiencies
and costs on the basis of soil and slope combinations. The article states that
BMPSAT is an Excel spreadsheet that could be modified for additional
evaluations of BMPs or site characteristics and that the flexibility of RUSLE2
allows BMPSAT to be easily customized for complex or simple slopes,
specific site characteristics, and to include additional BMPs.
Costs for the BMPs included in the analysis are from EPA-842-B-02-003
(National management measures to control nonpoint source pollution from
urban areas - draft). The modeling methodology could be of interest for soil
modeling.
Autumn DeWoody
2007
Cost-Effectiveness of Stormwater Infiltration BMPs in Los Angeles
County
University of California, Riverside
StormCon 2007
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Appendix B: Literature Search Annotated Bibliography
Abstract: Current stormwater regulations require infiltration and/or treatment of the
runoff generated by a minimum rain depth or flow rate at new developments
or redevelopments above a threshold size, but most existing facilities in Los
Angeles are not required to mitigate their onsite runoff. Available information
on stormwater infiltration BMP costs is often vague or inadequate and
outdated, and there is little data on urban Southern California BMP costs. This
research aims to provide clarity to decision makers on parcel-level strategies
that comply with stormwater regulations and boost groundwater supply. It
focuses on the retrofit of existing nonresidential parcels with stormwater
infiltration BMPs. The research begins with five cost/benefit case studies, then
follows with a BMP cost analysis using local area BMP data, and then
presents a cost-benefit analysis of parcel-level infiltration across a wide
variety of land uses, parcel sizes, and infiltration rates.
Comments: On the basis of a Los Angeles and San Gabriel Rivers Watershed Council
study evaluating the potential to retrofit typical urban neighborhoods to
promote infiltration, this paper evaluates the costs and benefits of retrofits to
determine whether the benefit of increased groundwater recharge justified the
expense of a BMP system. The cost/benefit analysis uses the actual capital
costs for the retrofit sites; the source costs were not presented.
Author(s):
Date:
Title:
Organization:
Source:
Abstract:
Jason Ziemer
2007
Complying with NPDES Phase II Requirements on a Major Highway
Construction Project with the Implementation of an Emerging BMP
Clear Water Compliance Services, Inc.
StormCon 2007
The Washington State Department of Transportation (WSDOT) and their
general contractors began a $126.3M construction project along 3.5 miles of
State Route (SR) 18 in Maple Valley, Washington in September, 2003. The
project included 15 new bridges, over 40 retaining walls and required more
than 850,000 cubic yards of earth moving. Initial stormwater engineering and
planning focused primarily on post construction stormwater considerations
included drainage improvements, construction of 14 stormwater storage and
treatment ponds, and the enhancement of 49 acres of wetlands. Planning for
construction-phase stormwater focused almost entirely on implementation and
maintenance of BMPs and was absent of specific considerations for meeting
water quality standards. This lack of planning eventual caused serious
problems and project delays. During the spring of 2004, WSDOT discovered
the general contractor had filled a wetland with woody debris without a
permit. Immediate action was taken by WSDOT, the U.S. Army Corps of
Engineers and the Washington State Department of Ecology (Ecology). This
paper presents the aggressive implementation of BMPs, including the use of
erosion control practices that had to be taken in order for the project to be in
compliance. Issues of turbidity were also discussed.
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Appendix B: Literature Search Annotated Bibliography
Comments: Example of a highway project in Washington State using a Chitosan-enhanced
sand filtration system to meet state requirement of <= 5 NTU above
background. Project specifications required treating 700 gpm with a
continuous effluent turbidity of less than 10 NTU. Article reports nearly
40,000 turbidity data points show an average turbidity of 236 NTU, 42.4 NTU
after pretreatment, and 1.04 NTU average discharge. The average cost per
gallon treated for the project was $0.017 per gallon. Warrants additional
review as part of the evaluation of numerical standards.
Author(s):
Date:
Title:
Organization:
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Abstract:
Comments:
Neil Myers and Ted Blahnik
2007
The Development Paradigm Shift: A Case Study
Williams Creek Consulting
StormCon 2007
This paper presents a case study from Williams Creek Consulting, a firm
specializing in LID and sustainable natural system designs for construction
stormwater management. Due to increased regulatory acceptance,
development companies are now utilizing more sustainable and lower impact
development solutions to provide for regulatory compliance, improve
marketability, increase profit and improve overall quality of life for the
community. A prime example of acceptance for sustainable sites engineering
for natural resource and stormwater management solutions is at a 1,700 acre
mixed-use development in the Midwest. This site is among the national
developer's first attempt at utilizing the more sustainable, lower impact
systems on a large scale and challenged the traditional design and construction
delivery methods within the Midwest. As the site begins to be developed,
significant cost savings are being realized during construction. BMPs planned
for this project included constructed wetlands, vegetated swales, bioretention
and rain gardens, wetland fringe along ponds, linear dry landscaped basins,
and more.
Might be useful for benefits analysis. Case study provides detailed cost
savings from low-impact development (vegetated swale, bioretention and rain
gardens, wetland fringe pond, and dry landscaped basins), reducing costs for
reinforced concrete storm pipes, storm structures, and site fill.
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Appendix B: Literature Search Annotated Bibliography
Author(s): Jamie Weist and Don Alexander
Date: 2007
Title: Saving Time and Money on Construction-Site SWPPPs
Organization: Woolpert, Inc.
Source: StormCon 2007
Abstract: Designed for contractors who must comply with federal, state, and local
stormwater, erosion, and sediment control regulations, this presentation shows
how to reduce the likelihood of fines due to noncompliance. A methodology
and automated process have been developed to help prepare stormwater
pollution prevention plans and comply with permit requirements, particularly
for contractors who are dealing with multiple construction sites.
Comments: The full text of the article is not available.
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Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Appendix C
Analysis of Construction Industry Trends Using
Notice of Intent Records
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Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
To estimate costs to different sectors of the industry and to projects of different sizes, U.S.
Environmental Protection Agency (EPA) developed a series of model projects that could serve as
the basis for developing mathematical models. A key source of information that EPA used in this
analysis is Construction Permit Notice of Intent (NOT) records, which EPA and state permitting
authorities collect. EPA collected NOT data for approximately 138,000 permits, containing data
from 38 states for construction activities occurring primarily between the mid-1990s and 2006.
Depending on the state, the number of NOT records available ranged from fewer than 10 to more
than 10,000. The data are available either from a database of permits processed directly by EPA
(referred to as the EPA_NOI database) or per-state databases obtained independently. In general,
the NOT records are sufficiently similar to allow pooling of all sources regardless of whether
EPA or an individual state is the permit processing entity.
In general, the data fields of greatest interest within an NOT record for EPA's analysis are the
following:
National Pollutant Discharge Elimination System (NPDES) Permit or State-specific
Identification Number
Name/Title of Proj ect or Facility
Acres Affected and/or Disturbed
Location of Project (e.g., latitude/longitude and/or street address)
Date of Project (e.g., date of permit award, start of construction)
Permitted Name and Contact Information
Not all NOI records collected contain the full array of data. Frequently, data fields are not filled
in completely for any single NOI record. In addition, some states do not appear to collect or
provide all the desired data fields in the files EPA collected. Also, in general, the more recent
records are more complete than older records, and more current years contain more permit
records for any given state. Overall, approximately half the NOI records collected covering all
locations and all years have the type and quality of data that support analyses of interest to EPA.
For this analysis, EPA chose to characterize the industry into three major project types. EPA
further subdivided these projects into three size categories, yielding a total of six model projects.
Small projects are defined as those smaller than 10 acres in size, medium projects are 10 or more
acres but less than 30 acres, while large projects are 20 or more acres in size. Table C-l presents
the matrix of model project types.
Table C-l. Model Site Matrix
Ultimate land use
Residential
Nonresidential
Transportation/linear projects
Size category
Small, medium and large
Small, medium and large
Small, medium and large
Examples
Single and multifamily subdivisions
Institutional, commercial, and industrial sites
Roadway, pipelines
For each of the six model projects, EPA analyzed the NOI records to determine the percentage of
total constructed acreage that each model project comprises and the he median site size in each
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Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
category. EPA also analyzed the NOT records to determine if any other major project types
existed.
The starting point for the analysis was identifying project type (i.e., future land use) on the basis
of key words found in project name data fields. The broad categories and their subcategories
identified according to a preliminary review of the NOT records were as follows:
Residential - single and multifamily dwellings
Nonresidential - commercial, industrial, institutional, places of worship, and schools
Infrastructure - transportation, rail, mining, airport, water projects
Farm - farm including poultry and dairy operation, and agriculture projects
As a first step, a suite of key words were identified for each of the subcategories, as a way of
placing projects in one of the four broad categories. For example, the project title "Smith
Condos" contains a key word, "Condos" which suggests the project is residential in nature.
"John's Dairy Farm" contains the key word combination of "Dairy Farm," which suggests an
agricultural project.
The search algorithm looked for occurrence of a single word from a list of key words and for key
word combinations. Through an iterative process, word combinations were created from actual
project names to help minimize identification errors. For example, identifying agricultural
projects based only on the word "Farm" generated errors because the name of many residential
projects contain the word, e.g., Farm Acres subdivision or Farm Estates. So, a review of
agriculture projects was performed to create phrases like "Poultry Unit" and "Turf Farm" to help
identify all apparent agriculture projects. Attachment A provides a list of key words and key
word combinations.
Once the type of construction project was known, other data fields within an NOT record (e.g.,
acreage disturbed) became much more useful. For the most part, follow-on analysis of NOT
record data was limited to totaling data fields within categories of land use, and performing
limited statistical analysis using industry standard software (i.e., Microsoft Excel).
As the identification of construction project type (i.e., future land use) involved searching
through thousands of data records using customized computer code, conducting quality control
(QC) checks of the search results was warranted. This check attempted to verify that the
computerized process was sufficiently robust to permit EPA's use of the results.
EPA's approach to use of the NOT information was to favor the highest quality information.
Because the original data set is large (approximately 138,000 NOIs were used for this analysis),
a subset contains sufficient data to perform a statistically defensible analysis. Various efforts are
appropriate to manage potential and actual shortcomings within the NOT data records. The results
of the current analysis (discussed below) are based on specific quality control activities
performed before analysis of NOT records. The activities are as follows:
C-2
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Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Management of Missing data
Where an NOT data record did not provide numeric information, it was not included in any
statistical summaries performed, i.e., if the field containing constructed acreage was blank it was
excluded from the analysis, not interpreted as "0" acres.
Unusual Data
Various checks were made to identify unusual data. For example, NOT records with very large
acreage (larger than 1,500 acres) were screened to verify the project type would require
extensive land area. If not, they were removed from the analysis. Another example is records
with unexpected dates (e.g., June 2nd, 1890) were not used in any assessment related to
construction duration or period.
Repetitive Records
An effort was made to identify and remove repeating records. Multiple listings of a single
construction site are in the NOT records, judging from project name, project location, and
construction site size information. The frequency of repeating records varies from state to state,
with some states reporting a project multiple times. There is some suggestion that multiple
listings relate to multiphase projects. While they represented a relatively small portion of the
total NOT data set, repeating records were reduced to a single record (one that seemed most
inclusive), where they could be identified.
Multiple Construction Subcategory Identifications
Hence, whenever a project title could be interpreted as falling into multiple categories (e.g.,
residential and commercial) it was removed from the analysis. For the results below, an NOT
record was not used, even if its project name was more strongly associated with one of two
subcategories, e.g., the project title contained two words generally associated with residential
projects and only one word generally associated with commercial project. The focus of the
analysis was to limit the degree of interpretation performed to a practical minimum.
Overall, approximately 4 percent of NOT records contain key words or key phrases that fall
within multiple categories.
Assessment of Automated Construction Subcategory Identifications
Internal checks were performed to identify the accuracy of automated keyword searches (using
computer code) as compared to key word interpretation performed by humans. The intent was to
provide information on the percent of projects where the computer code misinterpreted the
nature of construction activity.
If the automated (i.e., computer) characterization was correct most of the time, it is reasonable to
use the conclusions drawn from the results. If the computer characterization was substantially
wrong or biased, EPA could require alternative means to identify the nature individual NOIs,
perhaps including individually assessing tens of thousands of records manually.
Regarding the automated key word search, three conditions were assessed:
The computer code and human interpretation agree on a construction project
name/nature
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Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
The computer code misinterpreted the project nature, as judged by a review
performed by humans
The project nature is ambiguous, although it was assigned to a category on the basis
of the computer code key word search (i.e., human interpretation of the project
name/nature revealed that no clear conclusion could be drawn)
To characterize the performance of the automated key word search, NOT records were first
grouped into the broad categories (residential, nonresidential, infrastructure, and farm). Any
project not singularly assigned by the automated keyword search was excluded. Within each
broad category, identified projects were first randomized in order, mingling all projects
regardless of location, period of operation, and size. Next, the first 200 projects (at a minimum)
in each category were individually reviewed and characterized by a person. A judgment was
made as to whether the automated keyword search correctly characterized the individual
construction project.
Overall, the automated characterization was judged to be incorrect approximately 2 percent of
the time. In addition, approximately 4 percent of projects characterized through the automated
process were later judged by a person to be ambiguous. Projects judged to be ambiguous were
not necessarily incorrectly characterized; they might or might not be found to be correctly
characterized if additional data were made available at a later date.
In summary, it appears that the automated keyword search provides reasonably high accuracy
regarding its assessment of the future land use when broad categories of land use are used. Given
the relative high accuracy of the key word search, EPA elected to use the results of the
automated (computer) identification characterization of construction site type without correction.
Results of Assessment of NOI data records
Approximately 138,000 NOIs are available in files collected by EPA, and 61,500 records can be
placed in a single land use category with an approximate 95 percent accuracy on the basis of a
key word search. [Accuracy is based on a comparison between human interpretation of the
project title and computer-code interpretation of project title.] In addition to the 61,500 NOIs
assigned to a single land use category, an additional 2,500 NOIs can be placed in more than one
land use category according to the key word search and were not used in subsequent evaluations.
Only 41,000 categorized NOIs (of the 61,500) were from sources that provided construction
acreage information for a portion of their NOIs; the remainder is from state files without site size
data.
Identification and Processing of Relatively Infrequent Land Use Types
Approximately 3,000 of the 34,000 NOIs which listed project acreage were found to be from
small subcategories on the basis of the total acreage represented across all NOIs. The relatively
infrequent future land use subcategories are the following:
Railroad
Mine
Water projects
C-4
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Park
Airport
Farm
Collectively, these six subcategories contain about 10 percent of the total site acreage found
within the pool of NOT records. In terms of summarizing the results of the NOT assessment
herein, these subcategories are not prioritized because of their small individual contribution.
Creating individual construction sites models of these six subcategories would likely not alter the
national results significantly. EPA assumed that the influence of the six infrequent subcategories
is sufficiently represented in models of other, more common, land use types. In the case of the
Transportation/Linear category, a linear transportation model was used to represent the acreage
developed as railroad, water projects (e.g., pipelines) and airports. In terms of the acreage listed
in the NOI data pool, transportation alone makes up about 9 percent of the total, or about equal to
the collective acreage found in the other linear land uses.
Summarizing Future Land Use by Broad Land Use Categories
Across the suite of the land use categories analyzed, actual acreage was available for only 34,000
NOIs. This acreage was summed nationally for the most common land uses, and then the percent
contribution by each category was computed. The results are summarized in Table C-2. Note, in
the absence of railroad, water projects, and airports (neglected for their small individual
contribution), the original infrastructure group is left containing only transportation projects.
In summary, it appears that the land use models for residential, nonresidential, and transportation
(linear) projects can account for the majority of land use found within the NOI pool of data. In
addition, it appears appropriate to subdivide the broad land use categories into large and small
projects, with the division being at the 10-acre site size. While small projects make a small
contribution to the total acreage, they represent a large fraction of the total number of projects
permitted.
Inclusion of Small Sites
The Phase INPDES stormwater regulations, promulgated in 1990, required construction sites of
5 or more acres in size to obtain a permit. The Phase II NPDES regulations, promulgated in
1999, extended regulation to sites of 1 or more acre. So as not to skew the national distribution, a
simple assessment was performed to determine if the smallest sites (defined as being below 5
acres in size) were excluded from the pool of EPA's NOI data. A state-by-state review was
performed to determine the first year when sub-5 acre sites are found in the NOI records. Table
C-3 indicates the per-state summary of the results for sub-5 acre sites. Overall, between 95 and
100 percent of EPA's pool of NOI data originates after sub-5 acre sites are included in the NOI
records (typically starting in Year 2003). Table C-3 summarizes the results of this assessment.
C-5
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
able C-2. National Summary of NOI Assessment by Common Land Use Category and Site Size
Small Transportation Projects
Small Residential Projects
Small Non-residential Projects
Medium Transportation Projects
Medium Residential Projects
Medium Non-residential Projects
Large Transportation Projects
Large Residential Projects
Large Non-residential Projects
TOTALS
Number of
NOIs
1,261
8,322
12,915
395
4,236
3,232
407
2,130
1,353
34,251
Percent of
NOIs
3.7%
24.3%
37.7%
1.2%
12.4%
9.4%
1.2%
6.2%
4.0%
Acres in
Each NOI
Category
4,496
32,139
43,141
6,884
74,322
54,182
44,060
178,803
149,931
587,958
Percent of
Total NOI
Acres
0.8%
5.5%
7.3%
1.2%
12.6%
9.2%
7.5%
30.4%
25.5%
Median
Site Size
(acres)
3.0
3.0
2.6
16.0
16.7
15.0
78.9
33.0
51.0
* Note, approximately 2 percent of projects are believed to be incorrectly categorized, and up to 4 percent of
categorized projects are of an uncertain nature.
Table C-3. Evaluation of Sub-5 Acre Sites with NOI Records
State
AK
AL
AR
AZ
CA
CO
CT
DC
FL
GA
IA
ID
IL
KS
LA
MA
MI
Number in
EPA's NOI
population*
1,195
1
~
484
44
184
5
138
10
~
3
2,130
~
4
6
2,590
12
Year when sub-5 acre NOIs
appear in EPA's database
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
No data provided
Sub-5 acre NOIs starting in 2003
Sub-5 acre NOIs starting in 2003
Sub-5 acre NOIs starting in 1999
Data too limited to evaluate
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
No data provided
Data too limited to evaluate
Sub-5 acre NOIs starting in 2003
No data provided
Data too limited to evaluate
Data too limited to evaluate
Sub-5 acre NOIs starting in 2002
Data too limited to evaluate
Number of
independently
submitted
population**
13,276
320
13,591
20,751
~
~
~
20,395
21,912
~
8,747
~
1,441
~
~
Year when sub-5 acre NOIs
appear in individual databases
No acreage provided
No acreage provided
Sub-5 acre NOIs starting in 2002;
Post-2002 constitutes 98% of data
Sub-5 acre NOIs starting in 2001;
Post-2001 constitutes 95% of data
No acreage provided
No date fields provided, but 44% of
data is for sub-5 acre sites
Sub-5 acre NOIs starting in 2000;
Post-2000 constitutes 99% of data
No acreage provided
C-6
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
State
MN
MS
MT
ND
NE
NH
NM
NV
NY
OH
OK
OR
SD
TN
TX
UT
VT
WA
WI
WV
WY
Number in
EPA's NOI
population*
58
5
72
6
12
1,874
3,590
11
1
~
233
7
11
~
386
2
7
104
36
~
5
Year when sub-5 acre NOIs
appear in EPA's database
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
Data too limited to evaluate
Sub-5 acre NOIs starting in 2002
Sub-5 acre NOIs starting in 2001
Data too limited to evaluate
Data too limited to evaluate
No data provided
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
Data too limited to evaluate
No data provided
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
Data too limited to evaluate
Sub-5 acre NOIs starting in 2003
Data too limited to evaluate
No data provided
Data too limited to evaluate
Number of
independently
submitted
population**
~
1,624
~
~
~
~
~
~
~
9,181
~
~
1,381
8,815
~
~
~
1,800
~
1,219
~
Year when sub-5 acre NOIs
appear in individual databases
No acreage provided
Sub-5 acre NOIs starting in 2003;
Post-2003 constitutes 99% of data
Sub-5 acre NOIs starting in 2002;
Post-2002 constitutes 96% of data
Sub-5 acre NOIs starting in 1996;
Post- 1996 constitutes 100% of data
No acreage provided
Sub-5 acre NOIs starting in 2002;
Post-2002 constitutes 100% of data
* NOI permits processed directly by EPA
** Within databases obtained from individual states
Evaluation of Transportation Projects
Table C-4 contains additional data related to transportation projects listed within the pool of NOI
data. Tetra Tech combined all NOI records that appeared to be transportation related, and
attempted to obtain additional insight into the actual activity covered by the permit.
C-7
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Table C-4. Detailed Evaluation of Transportation-Related NOIs
Subcategory
Unassigned
Bridge
Hwy
Interchange
Office*
Road, Lane, Avenue
State Road
Total
Average
site
acreage
23.60
5.87
26.66
52.20
32.74
12.82
63.28
26.87
Total
acreage in
subcategory
15,502
980
9,384
261
3,798
5,835
19,680
55,440
Number
of NOIs
657
167
352
5
116
455
311
2063
Median
site size
3.00
6.00
4.79
23.00
Percentage
of listed
acreage
28.0%
1.8%
16.9%
0.5%
6.9%
10.5%
35.5%
Percentage
of assigned
NOIs
31.8%
8.1%
17.1%
0.2%
5.6%
22.1%
15.1%
* Some projects are identified only by reference to a DOT office location
As expected, a fraction of the transportation NOIs could not be characterized in terms of the type
of activity (approximately 28 percent). An example of this would be an NOI that lists only a
DOT contract number in the project name field. The remaining (assignable) projects were
divided into groups on the basis of a detailed key word search of the project title. Linear
roadway-related projects were found to be the dominant project type. Because linear
transportation projects collectively represent about 63 percent of all transportation project
acreage (State Roads, Road, Lane, Avenue, Highway) it seems reasonable for EPA to consider a
road project as its linear-type construction site model.
The NOI permit characterization is DCN 43093 and the NOI model site assessment is DCN
43094 in the Administrative Record.
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Attachment A: Key Word List
Subcategories of construction activities were developed on the basis of a review of NOT records.
The subcategories of interest and the broader categories that contain them are as follows:
Residential - single and multifamily dwellings
Nonresidential - commercial, industrial, institutional, places of worship, and schools
Infrastructure - transportation, rail, mine, airport, water projects
Farm - farm including poultry and dairy operation, and agriculture projects
The tables below indicate the relationship between key words and subcategories. Note that in
some cases a space preceded or followed the key word, but only the unique key words are
presented in the tables.
Farm Key Words
Chicken Farm
Dairy Farm
Egg Farm
Family Farm
Farms Dairy
Farms Hatchery
Fish Farm
Goat Farm
Grass Farm
Horse Farm
Pork Farm
Poultry
Poultry Farm
Sod Farm
Tree Farm
Turf Farm
C-9
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Residential Key Words
Acres
Addition
Apartment
Apt
Assisted Living
Commons
Condo
Condominium
Condos
Cottages
Development
Dvlpmnt
Dwelling
Estate
Heights
Home
Housing
Landing
Manor
Mobile Home
Residence
Residential
Retreat
RV Park
RV Resort
Senior Housing
Single Family
Square
Sub
Sub Division
Subdivision
Tenant
The Bluffs
The Hills
The Meadow
The Orchards
The Reserve
The Ridge
Towers
Town Home
Towne Crossing
Townhomes
Townhouse
Village
Villas
C-10
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Nonresidential commercial/industrial
84 Lumber
Administration Bid
Administration Building
Arena
Auto
Automotive
Autozone
Baking
Bank
Bbq
Beverage
Business
Business Park
Cafe
Cannery
Car Wash
Carwash
Casino
Century 21
Chiropractic
Citgo
Cleaners
Clinic
Clubhouse
College
Com Bldg
Commerce Center
Commercial
Convenience
Convenience Station
Corporate Headquarters
Costco
Country Club
Courthouse
Credit Services
Credit Union
Ctry Club
CVS
Dairy
Day Care
Daycare
Dealership
Dental
Department Store
Dept Store
Distribution Center
Dollar General
Energy
Equipment
Exxon
Family Dollar
Fedex
Filene's
Fire Station
Food Shops
Fuel Center
Furniture
Gas Station
Golf
Hardware
Healthcare
Home Depot
Hotel
Industrial
Industrial Park
Inn
Kohls
Kohl's
Lodge
Lowes
Lowe's
Mall
Manufacturing
Market
Market Place
Marketplace
Mart
Maverik
McDonalds
Medical
Medical Center
Medical Cntr
Millwork
Mini Storage
Ministorage
Motel
Municipal Building
Nursery
Office Addition
Office Bid
Office Building
Office Complex
Office Development
Package
Packaging
Parking
Pharmacy
Plaza
Plumbing
Power
Printing
Public Storage
Recyclers
Resort
Restaurant
Retail
Retail Shops
Roadhouse
Rodeo Arena
Sam's Club
Sandwich Shop
Sawmill
Self Storage
Service Station
Services Center
Shop
Shopping
Shopping Center
Sonic
Staples
Starbucks
Steakhouse
Stop & Shop
Stop And Shop
Storage
Store
Subway
Subway Sandwich
Supermarket
Tech. Center
Technology Center
Terminal
Theater
Town Hall
Townhall
Trading Post
Transport
Travel Center
Village Center
Walgreen
Walmart
Wal-Mart
Warehouse
Yacht Club
Yard
Ymca
C-ll
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Nonresidential other subcategories
Places of Worship
Church
Chapel
Congregation
Diocese
Jehovah
Of God
Sanctuary
School
Academy
Athletic Field
Ball Field
Ballfield
Baseball
Campus
Childrens Center
Dugout
Education
Elem
Elementary
Football
Kindergarten
Library
Practice Facility
Sch
School
Soccer
Sports Track
Stadium
Track & Field
Institutional
Armory
Booster Station
City Hall
Community Services
Correction
Dam
Facility
Federal Center
Garage
Gas Line
Gas Plant
Harbor
Hospital
Jail
Landfill
Library
Lift Station
Maintenance
Pipe
Plant
Pint
Police
Port Authority
Power
Power Line
Powerline
Public Infrastructure
Public Library
Utility
Visitors Center
C-12
-------
Appendix C: Analysis of Construction Industry Trends Using Notice of Intent Records
Infrastructure
Airport
Airpark
Airport
Hanger
Ramp
Runway
Spaceport
Tarmac
Taxilane
Taxiway
Water Projects
Lateral
Main
Pipeline
Potw
Sewer
Sewerage
Swr
Trunkline
Waste Water
Wastewater
water line
Water Main
Water Pollution
Water System
waterlines
Watermain
Wpc
Wwtf
Wwtp
Transportation
Bridge
Bridge Recon
Bypass
Dot
Freeway
Highway
Highway Department
Hwy
Hwy Department
Intersection
Overpass
Rd Realignment
Road Improvement
Road Realignment
Road Reconstruction
Road Relocation
Roadway Impr
Route
St Realignment
Street Improve
Street Realignment
Tollway
Transit
Transportation
Railroad
Railroad
Rail Road
Mine
Aggregates
Borrow
Coal
Gravel
Mine
Mining
Pit
Reclamation
Sand & Gravel
C-13
-------
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Appendix D
Precipitation Data Representative of Major
U.S. Metropolitan Areas
-------
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
OVERVIEW
The U.S. Environmental Protection Agency (EPA) used precipitation data to estimate costs and
pollutant load reductions for regulatory options. EPA developed a series of regional pollutant
load models using data from 11 indicator cities for the loadings analysis. These indicator cities
are shown in Table D-l. For the costing analysis, EPA used rainfall data for one indicator city in
each state. EPA used the same 11 indicator cities for the states described in Table D-l. For the
remaining states, a major urban area was chosen as the indicator; which in most cases was the
capital city. Precipitation data was acquired for each city using the National Oceanic and
Atmospheric Administration (NOAA) National Weather Service (NWS) Precipitation Frequency
Data Server (PFDS). The Hydrometeorological Design Studies Center (FtDSC) within the Office
of Hydrologic Development of the NWS is in an ongoing process of updating its precipitation
frequency estimates, which are available in NOAA Atlas 14 format. At the time of this writing,
only a portion of the United States had been updated into this format. Atlas 14 supercedes
precipitation frequency estimates contained in previous NWS publications. The updates are
based on more recent and extended data sets, currently accepted statistical approaches, and
improved spatial interpolation and mapping techniques. A complete list of NWS publications is
listed in Table D-2. The rainfall analysis data is DCN 43095 and an index of spatial data analyses
conducted for the proposed rule is DCN 43097 the Administrative Record.
Table D-l. EPA Region Indicators
EPA Region
1
2
3
4
5
6
7
8
9
10
Indicator city
Manchester, NH
Albany, NY
Washington, DC, VA, and MD
Atlanta, GA
Chicago, IL IN
Dallas, Fort Worth, and Arlington, TX
Kansas City, MO and KS
Denver and Aurora, CO
Las Vegas, NV
Boise City, ID, and Seattle, WA
D-l
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Table D-2. Current NWS Precipitation Frequency Publications
Location
Arizona, Nevada, New Mexico, Utah, and
Southeast California
Remainder of the Western United States
Delaware; Illinois; Indiana; Kentucky;
Maryland; New Jersey; North Carolina;
Ohio; Pennsylvania; South Carolina;
Tennessee; Virginia; West Virginia; and
Washington, DC
Remainder of the Eastern United States
Hawaii
Alaska
Puerto Rico
5 min-60 min
NOAA Atlas 14
(2003)
Arkell &
Richards (1986)
Frederick &
Miller (1979)
NOAA Atlas 14,
Volume 2 (June
2004)
Tech. Memo 35
(1977)
Tech. Paper 43
(1962)
Tech. Paper 47
(1963)
NOAA Atlas 14,
Volume 3
1 hr-24 hr
NOAA Atlas 14
(2003)
NOAA Atlas 2
(1973)
NOAA Atlas 14,
Volume 2
(June 2004)
Tech. Paper 40
(1961)
Tech. Paper 43
(1962)
Tech. Paper 47
(1963)
NOAA Atlas 14,
Volume 3
2 day-10 day
NOAA Atlas 14
(2003)
Tech. Paper 49
(1964)
NOAA Atlas 14,
Volume 2
(June 2004)
Tech. Paper 49
(1964)
Tech. Paper
51(1965)
Tech. Paper 52
(1965)
NOAA Atlas 14,
Volume 3
NOAA Atlas 14 contains precipitation frequency estimates with associated confidence limits for
the United States for 5-minute through 60-day durations at average recurrence intervals of 1 year
through 1,000 year. The estimates are based on the analysis of annual maximum series and then
converted to partial duration series results. Figure D-l shows an example of the Atlas 14
interface.
D-2
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
weather.gov *
OAA's National
Hydrometeorological Desi
Precipitation Frequency Data Se
PFDS Home Page
Documentation
CIS data Maps Help
VIRGINIA
Reset
1. DATA DESCRIPTION:
Time series type: Partial duration
2. SELECT LOCATION:
Select site from list:
Select observing site
Submit site
Enter location:
Latitude (decimal degrees): |jat_
Longitude (decimal degrees):
Ion
Submit location
Click on map to select location information:
Latitude: 138.653
Longitude: |-75.194
Elevation (feet): fl3~
Figure D-l. Example of PFDS Atlas 14 - Virginia.
The Atlas 14 interface allows the user to choose from various data parameters, such as data type
(precipitation depth or precipitation intensity); units (English or Metric); time series type (partial
duration or annual maximum); and the weather station location. The rainfall data results used in
EPA's analysis are shown in Table D-3.
For the states not currently updated by NOAA Atlas 14, the rainfall-frequency values for
selected durations were estimated using a series of maps presented in the older NWS
publications. The current modeling effort focused on the 2-year 24-hour, 10-year 24-hour, 25-
year 24-hour, and 10-year 6-hour precipitation data. Therefore, the data for the remainder of the
Western United States were estimated by using NOAA Atlas 2, Precipitation Frequency Atlas of
the Western United States (1973), which are generalized maps presented for 6- and 24-hour point
precipitation for the return periods of 2, 5, 10, 25, 50, and 100 years. Atlas 2 is published in
separate volumes for each of the states. Similarly, the maps presented in the corresponding
Technical Paper were used for the remainder of the Eastern United States and Hawaii. (Alaska
was not included in this analysis because EPA lacked sufficient data on the annual amount of
construction activity occurring in Alaska). Examples of an Atlas 2 map and a map from a
Technical Paper are shown in Figures D-6 and D-7, respectively.
Precipitation frequency results not generated by Atlas 14 for the remaining states (i.e., using
Atlas 2 or Technical Paper maps) are presented in Table D-4. The rainfall depths in Table D-4
were estimated by identifying the target city on the Atlas 2 or Technical Paper map and linearly
D-3
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
approximating the rainfall value. For example, if a city fell between a depth of 4.5 and 5 inches
and the city was approximately 20 percent of the map distance from the 5-inch line, a rainfall
depth of 4.9 inches was estimated. Note that the maps provided data for depth only. Intensity
estimates were calculated by dividing the duration (e.g., 6- or 24-hour) by the depth.
Additionally, Atlas 2 depths were converted from tenths of an inch to inches.
The above data were used in modeling state basin size requirements. New York and Wisconsin
specified alternate basin size storm events (10-year, 24-hours and 1-year, 24-hours, respectively).
Therefore, a depth of 4.4 inches for a 10-year 24-hour event in Albany, New York, and a depth
of 2.5 inches for a 1-year 24-hour event in Madison, Wisconsin were also estimated.
For use in estimating the annual volume of runoff produced, the PRISM Group analysis and
mapping services, developed by the Oregon State University, was used to obtain annual
precipitation data for all indicator cities and gauge locations. The PRISM data sets were
developed through projects funded partly by the U.S. Department of Agriculture (USD A)
Natural Resources Conservation Service, USD A Forest Service, NOAA Office of Global
Programs, and others. PRISM Group is responsible for nearly all major climate mapping efforts
at the federal level in the United States. Some examples of recent and current projects include the
following:
Climate Atlas of the United States, for the National Climatic Data Center
Precipitation and temperature maps for all 50 U.S. states and possessions, for USDA
Natural Resources Conservation Service
103 years of monthly temperature and precipitation maps for the lower 48 states, for
NASA/NOAA Office of Global Programs
The PRISM Model is a knowledge-based system that uses point measurements of precipitation,
temperature, and other climate elements to produce continuous, digital coverages. Figure D-2
provides an example of the PRISM Data Explorer interface.
D-4
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
ARNTNG: This application is for analyzing
leseries for single grid-point data ONLY. If
ou wish to retrieve larger regions, please use the
Igridded data which is available for FTP from
here. Any abuse of this system such as writing of
robots and programs that automatically query
many gridcetls IS PROHIBITED and wffl result
in denial of access.
Please contact us if you need assistance.
Click map to set gridceH coordinates
Use the MapServer Identify ' tool to query visible map layers.
Gridcell Time-Series Analysis
LocatbitjLonj
LaJ
Paratneterl| Precipitation _^J
Montk| Annual jj
Start Yean
Stop Year
Units:
*" English
Valid period
1895toMar-08
rsi
Query Refresh
Precipitation (in.)
DO DO-6-0.8 Q2.4-2.8 6-8
<0.1 DO.8-1.2 D2.8-3.2 B8-12
0.1-0.2 D1.2-1.G D3.2H.O D 12-16
DO.2-0.4 ni.6-2.0 B4-5 D 16-20
DO.-1-0.6 Q2.0-2.4 B5-6 D 20+
idit (C) 1005. Sbatial C limateftnalysife Servi
Show PRISM background | J a n
Figure D-2. Example of PRISM Interface.
The PRISM interface allows users to choose from various parameters such as months (January
through December, all months, and annual); start and stop years (1895 to current); and units
(English or Metric). The PRISM-required inputs are latitude and longitude points for all indicator
cities and gauge locations. Results were compiled of annual precipitation totals for the years of
1895 to 2007 from which a determination was made for the annual average for each indicator
city in each state (presented in Table D-5). The latitude and longitude point inputs for the PRISM
Gridcell analysis were obtained from NOAA Atlas 14 weather station locations [e.g., Phoenix
WSFO AP, AZ (02-6481)] where possible. For the states not currently updated by NOAA Atlas
14, the U.S. Geological Survey (USGS) Geographic Names Information System (GNIS) was
used to obtain latitude and longitude points.
D-5
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Figure D-3 provides an example of the USGS interface.
Geographic Names Information System (GNIS)
Query Form For The And Its Territories
Feature Name' uo
F-3atur£ Class: | Peculate-} Place *\ Definitions
Ele.atlor.-: j TJ |
* Feet f Meters
1025 545 features in the GUIS
Advanced Search
Search Antarctica
Search FIPS55 Dam
Search GSAOPMPala
Important Links
Click for in query
Click Frequently Ashed Questions (F&Gsi lab for important information.
"Elevations are from the Mll^oaj E^vefego Peigse-t
U.S. Board on Geographic Names
Stepping Intomnatlon
Figure D-3. Example of USGS GNIS Interface.
The indicator city and the state were input into this interface and then Populated Place under the
Feature Class field was selected for obtaining the latitude and longitude points. Once Send Query
is selected, the results are displayed in a table format as shown in the Figure D-4 example. The
user can then click the desired Feature Name in the list for a Detailed Report as shown in the
example in Figure D-5.
Click the feature name lor details and to access mao services
Click any column nai
^|__^_
! Montgomery
i Montgomery East
1 Hontuomerv Hill
1 Hontoomerv Lates
i north Montgomery
i The Brick Store
netcsorttf
165344
142708
1 3*636
1700463
142758
ie list ascending t
Populated Place
Populated Place
Populate
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
r=sti,r=IC: 1653*4
Hsn's Montgomery
Class: Populated Place
Csscfic-lisr: Capital of State of Alabama.
Colleete-d 'during: Phase I data compilation (1976-1881}, primarily from U.S. Geological Survey
Citaticn: 1:24.QOO-scale topographic maps joH:25K. Puerto Rico 1:2QK|, various edition dates, and from U.S.
B-oard on Gec-graphic Names files.
Epty Date: Q4-Sep-19SQ
Eiatir
*
Census Cod* Class Code GSACode OPM Code
£1330 C1
on Geographic Decisions
Feature Name Decision Year Authority Decision Type
Mcntscnre.-*/ 1S21 Biaro Dedsisn
Sequence County Cod-e State Cod* Counibf
1 Mcrtgc-r*.-/ 131 AlacaTa 01 US
Coordinates (One point per USGS topographic map containing the feature, NAD83)
Sequence LatitudejDEC} Longitud*lDEC( LatitudejDMS) Longitude(DMS> Map Nam*
222eeS'3f2 -S£.2S'39-£3'9 221200 K OS£1SOO',-V McntgcT:*.-yScijt
222-32-^714 .8S.2S23019 221203 K 08ei730vV M = it3C-reryf<=rtri
Figure D-5. Example of USGS GNIS Query Detail Report.
The Sequence 1 latitude (DEC) and longitude (DEC) data coordinates from the USGS GNIS
query results were used for use in the PRISM model for each indicator city.
D-7
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Table D-3. NOAA Atlas 14 Precipitation Frequency Results
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: ILLINOIS
Station: CHICAGO OHARE WSO ARP
Lon(dd): -87.9142
Lat(dd): 41.9861
Elev(feet): 66
Date/time: Thu Jan 31 08:44:02 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
Precipitation
2
5
10
25
50
100
200
500
1000
5-min
0.39
0.46
0.54
0.61
0.7
0.78
0.85
0.93
1.04
1.13
Intensity
5.47
6.48
7.36
8.45
9.36
10.24
11.18
12.46
0
10-
min
0.6
0.71
0.84
0.95
1.08
1.18
1.28
1.39
1.53
1.64
15-
min
0.73
0.87
1.03
1.17
1.33
1.46
1.59
1.73
1.9
2.05
30-
min
0.97
1.17
1.41
1.62
1.88
2.09
2.3
2.52
2.82
3.08
60-
min
1.19
1.43
1.77
2.06
2.44
2.76
3.08
3.43
3.9
4.32
120-
min
1.39
1.68
2.1
2.47
2.94
3.35
3.77
4.2
4.81
5.33
3-hr
1.49
1.8
2.27
2.68
3.21
3.67
4.13
4.63
5.31
5.91
,, 12-
6-hr ,
hr
1.78 2.05
2.15 2.47
2.75 3.13
3.3 3.74
4.05 4.57
4.73 5.32
5.46 6.11
6.26 6.98
7.42 8.24
8.47 9.38
24-hr
2.34
2.85
3.64
4.29
5.25
6.07
6.96
7.93
9.38
10.62
2-
day
2.7
3.26
4.11
4.81
5.83
6.68
7.6
8.61
10.08
11.32
4-
day
3.08
3.7
4.55
5.26
6.28
7.13
8.05
9.04
10.56
11.86
7-
day
3.58
4.27
5.16
5.88
6.9
7.73
8.61
9.54
10.92
12.19
10-
day
4.05
4.81
5.77
6.57
7.69
8.61
9.59
10.63
12.12
13.38
20-
day
5.53
6.54
7.71
8.63
9.88
10.85
11.85
12.86
14.25
15.34
30-
day
6.88
8.1
9.41
10.39
11.65
12.6
13.52
14.44
15.61
16.49
45- 60-
day day
8.64 10.42
10.15 12.22
11.61 13.94
12.68 15.2
14 16.78
14.98 17.93
15.9 19.01
16.77 20.03
17.87 21.3
18.66 22.21
Estimates (in/hr)
4.27
5.03
5.68
6.46
7.09
7.7
8.35
9.16
0
3.48
4.12
4.66
5.32
5.85
6.38
6.92
7.62
0
2.33
2.82
3.24
3.75
4.18
4.61
5.05
5.64
0
1.43
1.77
2.06
2.44
2.76
3.08
3.43
3.9
0
0.84
1.05
1.23
1.47
1.68
1.88
2.1
2.4
0
0.6
0.76
0.89
1.07
1.22
1.38
1.54
1.77
0
0.36 0.21
0.46 0.26
0.55 0.31
0.68 0.38
0.79 0.44
0.91 0.51
1.04 0.58
1.24 0.68
0 0
0.12
0.15
0.18
0.22
0.25
0.29
0.33
0.39
0
0.07
0.09
0.1
0.12
0.14
0.16
0.18
0.21
0
0.04
0.05
0.05
0.07
0.07
0.08
0.09
0.11
0
0.03
0.03
0.03
0.04
0.05
0.05
0.06
0.07
0
0.02
0.02
0.03
0.03
0.04
0.04
0.04
0
0
0.01
0.02
0.02
0.02
0.02
0.02
0.03
0
0
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0 0
0 0
Date/time: Thu Jan 31 08:47:43 EST 2008
D-8
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: NEW MEXICO
Station: SANTA FE
Lon(dd): 105.9
Lat(dd): 35.6833
Elev(feet): 7582
Date/time: Thu Jan 31 10:56:42 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
Precipitation
2
5
10
25
50
100
200
500
1000
5-min
0.2
0.26
0.34
0.41
0.5
0.56
0.64
0.71
0.81
0.89
Intensity
3.1
4.13
4.91
5.96
6.76
7.64
8.51
9.7
0
10-
min
0.3
0.39
0.52
0.62
0.76
0.86
0.97
1.08
1.23
1.35
15-
min
0.38
0.49
0.65
0.77
0.94
1.06
1.2
1.34
1.52
1.67
30-
min
0.51
0.66
0.87
1.04
1.26
1.43
1.62
1.8
2.05
2.25
60-
min
0.63
0.81
1.08
1.28
1.56
1.77
2
2.23
2.54
2.79
120-
min
0.76
0.97
1.28
1.52
1.84
2.1
2.38
2.67
3.07
3.38
3-hr 6-hr 1,2"
hr
0.82 0.96 1.09
1.04 1.2 1.37
1.34 1.52 1.71
1.59 1.77 1.98
1.93 2.13 2.36
2.19 2.4 2.64
2.47 2.68 2.94
2.77 2.98 3.23
3.18 3.38 3.63
3.51 3.7 3.95
24-
hr
1.24
1.54
1.92
2.22
2.62
2.93
3.26
3.58
4.02
4.35
2-
day
1.4
1.75
2.16
2.5
2.94
3.29
3.64
3.99
4.46
4.83
4-
day
1.62
2.02
2.5
2.88
3.39
3.78
4.18
4.58
5.12
5.54
7-
day
1.92
2.39
2.94
3.36
3.92
4.36
4.79
5.22
5.79
6.21
10-
day
2.18
2.71
3.34
3.84
4.5
5
5.51
6.02
6.69
7.21
20-
day
2.91
3.62
4.41
5.01
5.78
6.36
6.91
7.45
8.14
8.64
30-
day
3.56
4.42
5.35
6.04
6.92
7.55
8.17
8.75
9.47
9.99
45-
day
4.46
5.53
6.62
7.41
8.39
9.07
9.72
10.31
11.04
11.54
60-
day
5.16
6.41
7.68
8.59
9.7
10.48
11.21
11.88
12.69
13.25
Estimates (in/hr)
2.36
3.14
3.73
4.54
5.15
5.81
6.47
7.38
0
1.95
2.6
3.08
3.75
4.25
4.81
5.35
6.1
0
1.31
1.75
2.08
2.52
2.86
3.24
3.6
4.11
0
0.81
1.08
1.28
1.56
1.77
2
2.23
2.54
0
0.48
0.64
0.76
0.92
1.05
1.19
1.34
1.54
0
0.35 0.2 0.11
0.45 0.25 0.14
0.53 0.3 0.16
0.64 0.36 0.2
0.73 0.4 0.22
0.82 0.45 0.24
0.92 0.5 0.27
1.06 0.56 0.3
000
0.06
0.08
0.09
0.11
0.12
0.14
0.15
0.17
0
0.04
0.05
0.05
0.06
0.07
0.08
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.04
0.05
0.05
0
0.01
0.02
0.02
0.02
0.03
0.03
0.03
0.03
0
0.01
0.01
0.02
0.02
0.02
0.02
0.03
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0
0
Date/time: Thu Jan 31 10:57:41 EST 2008
D-9
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: ARIZONA
Station: PHOENIX WSFO AP
Lon(dd): -111.99
Lat(dd): 33.4431
Elev(feet): 1148
Date/time: Thu Jan 31 11:18:08 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
Precipitation
2
5
10
25
50
100
200
500
1000
5-min
0.17
0.23
0.31
0.38
0.46
0.53
0.6
0.67
0.76
0.83
Intensity
2.74
3.76
4.52
5.56
6.37
7.19
8.03
9.14
0
10-
min
0.27
0.35
0.48
0.57
0.7
0.81
0.91
1.02
1.16
1.27
15-
min
0.33
0.43
0.59
0.71
0.87
1
1.13
1.26
1.44
1.57
30-
min
0.44
0.58
0.79
0.96
1.18
1.35
1.52
1.7
1.94
2.12
60-
min
0.55
0.72
0.98
1.19
1.46
1.67
1.88
2.1
2.4
2.62
120-
min
0.63
0.81
1.09
1.31
1.6
1.83
2.07
2.3
2.62
2.87
3-hr 6-hr 1,2"
hr
0.67 0.81 0.91
0.86 1.03 1.16
1.14 1.33 1.48
1.36 1.57 1.73
1.67 1.9 2.06
1.92 2.16 2.32
2.18 2.43 2.59
2.45 2.7 2.85
2.83 3.08 3.22
3.13 3.37 3.5
24-
hr
1.1
1.4
1.81
2.14
2.59
2.95
3.33
3.71
4.24
4.66
2-
day
1.21
1.55
2.03
2.42
2.96
3.38
3.83
4.31
4.96
5.49
4-
day
1.32
1.68
2.21
2.64
3.25
3.73
4.26
4.81
5.59
6.22
7-
day
1.45
1.85
2.43
2.9
3.57
4.1
4.67
5.26
6.11
6.79
10-
day
1.58
2.02
2.65
3.16
3.88
4.45
5.05
5.69
6.57
7.29
20-
day
1.93
2.48
3.26
3.86
4.65
5.26
5.88
6.51
7.35
8
30-
day
2.25
2.89
3.8
4.49
5.42
6.12
6.85
7.58
8.56
9.31
45-
day
2.61
3.35
4.41
5.19
6.21
6.97
7.74
8.49
9.49
10.23
60-
day
2.89
3.72
4.88
5.72
6.82
7.62
8.42
9.2
10.21
10.96
Estimates (in/hr)
2.08
2.86
3.44
4.23
4.85
5.47
6.11
6.96
0
1.72
2.36
2.85
3.5
4.01
4.52
5.05
5.75
0
1.16
1.59
1.92
2.35
2.7
3.04
3.4
3.87
0
0.72
0.98
1.19
1.46
1.67
1.88
2.1
2.4
0
0.4
0.55
0.66
0.8
0.92
1.03
1.15
1.31
0
0.29 0.17 0.1
0.38 0.22 0.12
0.45 0.26 0.14
0.56 0.32 0.17
0.64 0.36 0.19
0.73 0.41 0.21
0.82 0.45 0.24
0.94 0.51 0.27
000
0.06
0.08
0.09
0.11
0.12
0.14
0.15
0.18
0
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0
0.02
0.02
0.03
0.03
0.04
0.04
0.05
0.06
0
0.01
0.01
0.02
0.02
0.02
0.03
0.03
0.04
0
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
0
0.01
0.01
0.01
0.01
0.01
0.01
0
0
0
0
0
0.01
0.01
0.01
0.01
0
0
0
0
0
0
0.01
0.01
0.01
0
0
Date/time: Thu Jan 31 11:19:49 EST 2008
D-10
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: UTAH
Station: SALT LAKE CITY NWSFO
Lon(dd): -111.955
Lat(dd): 40.7725
Elev(feet): 4235
Date/time: Thu Jan 31 14:22:26 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
Precipitation
Freq (yr)
2
5
10
25
50
100
200
500
1000
5-min
0.12
0.15
0.21
0.26
0.34
0.42
0.52
0.63
0.82
0.99
Intensity
5-min
1.81
2.48
3.08
4.12
5.09
6.22
7.57
9.79
0
Date/time: Thu Jan 3 1
10-
min
0.18
0.23
0.32
0.39
0.52
0.65
0.79
0.96
1.24
1.5
15-
min
0.23
0.29
0.39
0.48
0.65
0.8
0.98
1.19
1.54
1.86
30-
min
0.3
0.39
0.53
0.65
0.87
1.08
1.32
1.6
2.07
2.51
60-
min
0.38
0.48
0.65
0.81
1.08
1.33
1.63
1.99
2.57
3.11
120-
min
0.5
0.61
0.8
0.97
1.25
1.51
1.83
2.2
2.81
3.37
. , , , 12- 24-
3-hr 6-hr , ,
hr hr
0.58 0.75 0.94 1.14
0.71 0.92 1.14 1.4
0.89 1.1 1.37 1.67
1.05 1.27 1.57 1.9
1.31 1.53 1.88 2.21
1.55 1.75 2.13 2.45
1.84 2 2.41 2.69
2.21 2.28 2.7 2.95
2.82 2.88 3.14 3.29
3.38 3.44 3.5 3.54
2-
day
1.29
1.58
1.89
2.15
2.49
2.76
3.03
3.3
3.66
3.94
4-
day
1.5
1.84
2.2
2.51
2.94
3.27
3.61
3.96
4.43
4.8
7-
day
1.74
2.13
2.55
2.9
3.38
3.75
4.13
4.51
5.03
5.42
10-
day
1.96
2.4
2.86
3.23
3.72
4.08
4.44
4.8
5.26
5.6
20-
day
2.56
3.15
3.73
4.17
4.74
5.15
5.54
5.92
6.38
6.71
30-
day
3.1
3.8
4.47
4.99
5.65
6.13
6.59
7.02
7.57
7.96
45-
day
3.84
4.7
5.51
6.15
6.97
7.56
8.13
8.67
9.35
9.82
60-
day
4.56
5.59
6.55
7.3
8.24
8.92
9.57
10.18
10.93
11.46
Estimates (in/hr)
10-
min
1.38
1.89
2.35
3.13
3.87
4.73
5.77
7.45
0
15-
min
1.14
1.56
1.94
2.59
3.2
3.91
4.76
6.16
0
14:23:39 EST
30-
min
0.77
1.05
1.31
1.74
2.15
2.63
3.21
4.15
0
2008
60-
min
0.48
0.65
0.81
1.08
1.33
1.63
1.99
2.57
0
120-
min
0.31
0.4
0.48
0.63
0.76
0.91
1.1
1.41
0
_ , , , 12- 24-
3-hr 6-hr . .
hr hr
0.24 0.15 0.09 0.06
0.3 0.18 0.11 0.07
0.35 0.21 0.13 0.08
0.44 0.26 0.16 0.09
0.52 0.29 0.18 0.1
0.61 0.33 0.2 0.11
0.74 0.38 0.22 0.12
0.94 0.48 0.26 0.14
0000
2-
day
0.03
0.04
0.04
0.05
0.06
0.06
0.07
0.08
0
4-
day
0.02
0.02
0.03
0.03
0.03
0.04
0.04
0.05
0
7-
day
0.01
0.02
0.02
0.02
0.02
0.02
0.03
0.03
0
10-
day
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
0
20-
day
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
30-
day
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
45-
day
0
0.01
0.01
0.01
0.01
0.01
0.01
0
0
60-
day
0
0
0.01
0.01
0.01
0.01
0.01
0
0
D-ll
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: NEVADA
Station: LAS VEGAS WSO AIRPORT
Lon(dd): -115.167
Lat(dd): 36.0833
Elev(feet): 2152
Date/time: Thu Jan 31 14:25:16 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
Precipitation
Freq (yr)
2
5
10
25
50
100
200
500
1000
5-min
0.12
0.15
0.22
0.27
0.35
0.41
0.48
0.56
0.67
0.77
Intensity
5-min
1.82
2.59
3.24
4.16
4.91
5.78
6.7
8.08
0
Date/time: Thu Jan 3 1
10-
min
0.17
0.23
0.33
0.41
0.53
0.62
0.73
0.85
1.02
1.17
15-
min
0.22
0.29
0.41
0.51
0.66
0.77
0.91
1.05
1.27
1.45
30-
min
0.29
0.39
0.55
0.69
0.88
1.04
1.23
1.42
1.71
1.96
60-
min
0.36
0.48
0.68
0.85
1.09
1.29
1.52
1.76
2.12
2.42
120-
min
0.45
0.59
0.82
1
1.26
1.48
1.72
1.98
2.36
2.67
3-hr 6-hr 1,2"
hr
0.5 0.61 0.7
0.65 0.79 0.92
0.89 1.07 1.25
1.07 1.29 1.48
1.34 1.58 1.8
1.54 1.82 2.03
1.77 2.07 2.27
2.01 2.33 2.5
2.39 2.69 2.83
2.69 3 3.07
24-
hr
0.77
1
1.37
1.62
1.96
2.2
2.46
2.7
3.03
3.27
2-
day
0.8
1.05
1.42
1.68
2.02
2.27
2.51
2.75
3.05
3.28
4-
day
0.88
1.16
1.58
1.87
2.24
2.52
2.78
3.04
3.38
3.63
7-
day
0.96
1.27
1.73
2.04
2.43
2.71
2.97
3.22
3.55
3.79
10-
day
1.04
1.37
1.86
2.19
2.59
2.88
3.15
3.4
3.73
3.97
20-
day
1.18
1.58
2.18
2.58
3.07
3.42
3.76
4.09
4.49
4.77
30-
day
1.34
1.8
2.54
3.05
3.69
4.16
4.61
5.05
5.61
6.01
45-
day
1.46
1.97
2.83
3.42
4.19
4.76
5.33
5.89
6.6
7.13
60-
day
1.61
2.19
3.2
3.91
4.84
5.55
6.26
6.97
7.91
8.61
Estimates (in/hr)
10-
min
1.39
1.97
2.47
3.17
3.74
4.4
5.1
6.14
0
14:33
15-
min
1.15
1.63
2.04
2.62
3.09
3.64
4.22
5.08
0
:29EST
30-
min
0.77
1.1
1.37
1.76
2.08
2.45
2.84
3.42
0
2008
60-
min
0.48
0.68
0.85
1.09
1.29
1.52
1.76
2.12
0
120-
min
0.29
0.41
0.5
0.63
0.74
0.86
0.99
1.18
0
3-hr 6-hr \2~
hr
0.22 0.13 0.08
0.3 0.18 0.1
0.36 0.22 0.12
0.45 0.26 0.15
0.51 0.3 0.17
0.59 0.35 0.19
0.67 0.39 0.21
0.8 0.45 0.23
000
24-
hr
0.04
0.06
0.07
0.08
0.09
0.1
0.11
0.13
0
2-
day
0.02
0.03
0.04
0.04
0.05
0.05
0.06
0.06
0
4-
day
0.01
0.02
0.02
0.02
0.03
0.03
0.03
0.04
0
7-
day
0.01
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
10-
day
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0
0
20-
day
0
0
0.01
0.01
0.01
0.01
0.01
0
0
30-
day
0
0
0
0.01
0.01
0.01
0.01
0
0
45-
day
0
0
0
0
0
0
0.01
0
0
60-
day
0
0
0
0
0
0
0
0
0
D-12
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: INDIANA
Station: INDIANAPOLIS WSFO AP
Lon(dd): -86.2789
Lat(dd): 39.7317
Elev(feet): 780
Date/time: Thu Jan 31 14:35:02 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.38
0.46
0.55
0.62
0.71
0.78
0.85
0.93
1.02
1.1
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.48
6.56
7.42
8.51
9.38
10.22
11.1
12.29
0
10-
min
0.6
0.71
0.85
0.95
1.08
1.19
1.28
1.38
1.5
1.6
15-
min
0.73
0.87
1.04
1.17
1.34
1.47
1.59
1.72
1.88
2
30-
min
0.97
1.17
1.43
1.63
1.89
2.1
2.3
2.51
2.78
2.99
60-
min
1.18
1.43
1.79
2.07
2.46
2.76
3.08
3.4
3.85
4.2
120-
min
1.39
1.68
2.11
2.45
2.94
3.33
3.75
4.19
4.81
5.31
3-hr 6-hr 1,2"
hr
1.47 1.74 2.07
1.78 2.11 2.49
2.24 2.67 3.1
2.61 3.12 3.6
3.14 3.77 4.29
3.58 4.31 4.86
4.05 4.89 5.46
4.55 5.51 6.08
5.26 6.41 6.97
5.84 7.15 7.68
24-
hr
2.46
2.95
3.62
4.13
4.83
5.38
5.94
6.5
7.27
7.86
2-
day
2.87
3.43
4.19
4.76
5.54
6.15
6.76
7.39
8.22
8.86
4-
day
3.26
3.89
4.69
5.31
6.15
6.81
7.47
8.13
9.02
9.71
7-
day
3.85
4.58
5.49
6.22
7.2
7.98
8.76
9.56
10.63
11.46
10-
day
4.39
5.21
6.23
7.03
8.12
8.98
9.84
10.72
11.89
12.8
20-
day
5.99
7.09
8.36
9.35
10.65
11.66
12.66
13.65
14.95
15.94
30-
day
7.39
8.71
10.13
11.22
12.65
13.74
14.81
15.85
17.2
18.21
45- 60-
day day
9.35 11.2
10.97 13.12
12.64 15.02
13.92 16.49
15.56 18.36
16.79 19.75
17.97 21.09
19.1 22.37
20.54 23.98
21.59 25.15
Estimates (in/hr)
4.28
5.1
5.72
6.51
7.11
7.7
8.29
9.03
0
3.49
4.18
4.69
5.36
5.87
6.38
6.87
7.51
0
2.33
2.86
3.26
3.79
4.19
4.6
5.01
5.57
0
1.43
1.79
2.07
2.46
2.76
3.08
3.4
3.85
0
0.84
1.05
1.23
1.47
1.67
1.88
2.1
2.41
0
0.59 0.35 0.21
0.75 0.45 0.26
0.87 0.52 0.3
1.05 0.63 0.36
1.19 0.72 0.4
1.35 0.82 0.45
1.51 0.92 0.5
1.75 1.07 0.58
000
0.12
0.15
0.17
0.2
0.22
0.25
0.27
0.3
0
0.07
0.09
0.1
0.12
0.13
0.14
0.15
0.17
0
0.04
0.05
0.06
0.06
0.07
0.08
0.08
0.09
0
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0.06
0
0.02
0.03
0.03
0.03
0.04
0.04
0.04
0
0
0.01
0.02
0.02
0.02
0.02
0.03
0.03
0
0
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0.02 0.01
0.02 0.02
0 0
0 0
Date/time: Thu Jan 31 14:36:24 EST 2008
D-13
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: OHIO
Station: COLUMBUS WSO AIRPORT
Lon(dd): -82.8808
Lat(dd): 39.9914
Elev(feet): 820
Date/time: Thu Jan 31 13:06:58 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.35
0.42
0.5
0.57
0.65
0.71
0.78
0.84
0.93
0.99
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.05
6.05
6.83
7.82
8.58
9.34
10.1
11.12
0
10-
min
0.55
0.66
0.78
0.88
1
1.08
1.17
1.26
1.36
1.44
15-
min
0.67
0.8
0.96
1.08
1.23
1.34
1.46
1.56
1.7
1.8
30-
min
0.89
1.07
1.32
1.5
1.74
1.92
2.1
2.28
2.52
2.7
60-
min
1.09
1.32
1.65
1.91
2.25
2.53
2.81
3.1
3.48
3.79
120-
min
1.27
1.54
1.93
2.24
2.67
3.02
3.39
3.77
4.3
4.73
3-hr 6-hr 1,2"
hr
1.35 1.61 1.89
1.63 1.94 2.26
2.04 2.41 2.8
2.37 2.8 3.25
2.84 3.36 3.9
3.21 3.83 4.44
3.61 4.33 5.03
4.03 4.86 5.65
4.62 5.62 6.55
5.09 6.25 7.29
24-
hr
2.19
2.62
3.23
3.73
4.44
5.03
5.64
6.3
7.23
7.98
2-
day
2.53
3.03
3.7
4.25
5.03
5.66
6.33
7.02
8
8.78
4-
day
2.9
3.45
4.19
4.79
5.62
6.29
6.98
7.7
8.68
9.46
7-
day
3.48
4.14
5.01
5.7
6.68
7.46
8.27
9.11
10.28
11.2
10-
day
3.97
4.71
5.63
6.37
7.38
8.18
8.99
9.83
10.96
11.85
20-
day
5.52
6.51
7.65
8.54
9.71
10.62
11.51
12.4
13.56
14.41
30-
day
6.92
8.14
9.45
10.44
11.72
12.69
13.61
14.5
15.63
16.45
45- 60-
day day
8.81 10.64
10.35 12.46
11.88 14.21
13.04 15.52
14.49 17.17
15.55 18.38
16.55 19.5
17.5 20.57
18.67 21.87
19.5 22.78
Estimates (in/hr)
3.94
4.7
5.27
5.98
6.51
7.03
7.54
8.18
0
3.21
3.85
4.32
4.92
5.37
5.82
6.25
6.8
0
2.15
2.63
3
3.48
3.84
4.2
4.56
5.04
0
1.32
1.65
1.91
2.25
2.53
2.81
3.1
3.48
0
0.77
0.96
1.12
1.34
1.51
1.69
1.88
2.15
0
0.54 0.32 0.19
0.68 0.4 0.23
0.79 0.47 0.27
0.94 0.56 0.32
1.07 0.64 0.37
1.2 0.72 0.42
1.34 0.81 0.47
1.54 0.94 0.54
000
0.11
0.13
0.16
0.19
0.21
0.24
0.26
0.3
0
0.06
0.08
0.09
0.1
0.12
0.13
0.15
0.17
0
0.04
0.04
0.05
0.06
0.07
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0
0.02
0.02
0.03
0.03
0.03
0.04
0.04
0.05
0
0.01
0.02
0.02
0.02
0.02
0.02
0.03
0
0
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0.02 0.01
0 0
0 0
Date/time: Thu Jan 31 13:07:44 EST 2008
D-14
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: PENNSYLVANIA
Station: PHILADELPHIA WSO AP
Lon(dd): -75.2311
Lat(dd): 39.8683
Elev(feet): 6
Date/time: Thu Jan 31 14:50:28 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.35
0.41
0.49
0.54
0.6
0.64
0.68
0.72
0.76
0.79
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
4.97
5.83
6.43
7.18
7.68
8.17
8.59
9.08
0
10-
min
0.56
0.66
0.78
0.86
0.95
1.02
1.08
1.14
1.2
1.24
15-
min
0.69
0.83
0.98
1.08
1.21
1.29
1.37
1.43
1.51
1.56
30-
min
0.95
1.15
1.4
1.57
1.79
1.94
2.09
2.23
2.4
2.52
60-
min
1.19
1.44
1.79
2.05
2.38
2.63
2.88
3.13
3.44
3.68
120-
min
1.43
1.73
2.17
2.49
2.93
3.26
3.6
3.93
4.38
4.72
3-hr 6-hr
1.56 1.93
1.89 2.33
2.37 2.91
2.73 3.38
3.22 4.03
3.61 4.56
4.01 5.11
4.4 5.69
4.94 6.51
5.36 7.16
12-
hr
2.34
2.82
3.54
4.13
5.01
5.75
6.55
7.42
8.68
9.73
24-
hr
2.68
3.23
4.08
4.8
5.85
6.74
7.7
8.76
10.3
11.6
2-
day
3.07
3.71
4.7
5.51
6.68
7.66
8.71
9.85
11.48
12.84
4-
day
3.44
4.15
5.22
6.1
7.36
8.4
9.52
10.72
12.45
13.87
7- 10-
day day
3.98 4.46
4.78 5.34
5.94 6.54
6.89 7.5
8.27 8.87
9.42 9.97
10.64 11.12
11.95 12.32
13.82 14.05
15.36 15.48
20-
day
6.01
7.13
8.53
9.63
11.14
12.32
13.52
14.74
16.38
17.64
30-
day
7.49
8.83
10.34
11.51
13.07
14.26
15.44
16.61
18.13
19.26
45- 60-
day day
9.49 11.32
11.15 13.27
12.86 15.18
14.15 16.59
15.79 18.37
17.02 19.67
18.18 20.88
19.29 22.01
20.67 23.39
21.66 24.36
Estimates (in/hr)
3.97
4.67
5.15
5.72
6.11
6.49
6.81
7.19
0
3.32
3.94
4.34
4.83
5.16
5.47
5.73
6.03
0
2.3
2.8
3.14
3.58
3.89
4.19
4.46
4.8
0
1.44
1.79
2.05
2.38
2.63
2.88
3.13
3.44
0
0.87
1.08
1.25
1.46
1.63
1.8
1.97
2.19
0
0.63 0.39
0.79 0.49
0.91 0.56
1.07 0.67
1.2 0.76
1.33 0.85
1.47 0.95
1.65 1.09
0 0
0.23
0.29
0.34
0.42
0.48
0.54
0.62
0.72
0
0.13
0.17
0.2
0.24
0.28
0.32
0.36
0.43
0
0.08
0.1
0.11
0.14
0.16
0.18
0.21
0.24
0
0.04
0.05
0.06
0.08
0.09
0.1
0.11
0.13
0
0.03 0.02
0.04 0.03
0.04 0.03
0.05 0.04
0.06 0.04
0.06 0.05
0.07 0.05
0.08 0
0 0
0.01
0.02
0.02
0.02
0.03
0.03
0.03
0
0
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0.02 0.01
0.02 0.02
0 0
0 0
Date/time: Thu Jan 31 14:51:05 EST 2008
D-15
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: KENTUCKY
Station: FRANKFORT LOCK 4
Lon(dd): -84.8817
Lat(dd): 38.235
Elev(feet): 600
Date/time: Thu Jan 31 14:52:10 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.38
0.45
0.52
0.59
0.67
0.73
0.79
0.85
0.94
1
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.35
6.29
7.06
8.02
8.77
9.49
10.21
11.23
0
10-
min
0.59
0.7
0.82
0.91
1.03
1.11
1.2
1.28
1.38
1.46
15-
min
0.72
0.86
1.01
1.12
1.27
1.38
1.49
1.59
1.73
1.83
30-
min
0.96
1.15
1.38
1.57
1.8
1.98
2.16
2.34
2.58
2.76
60-
min
1.17
1.41
1.74
2
2.35
2.62
2.9
3.19
3.59
3.9
120-
min
1.37
1.65
2.04
2.36
2.8
3.15
3.53
3.92
4.47
4.92
3-hr 6-hr 1,2"
hr
1.47 1.8 2.12
1.77 2.16 2.54
2.19 2.67 3.13
2.54 3.09 3.62
3.03 3.7 4.32
3.43 4.2 4.89
3.86 4.74 5.5
4.31 5.31 6.16
4.96 6.14 7.09
5.49 6.82 7.86
24-hr
2.51
O
3.73
4.34
5.23
5.98
6.79
7.67
8.95
10.01
2-
day
2.96
3.55
4.38
5.06
6.04
6.84
7.69
8.6
9.89
10.95
4-
day
3.34
4
4.89
5.62
6.63
7.44
8.29
9.17
10.39
11.35
7-
day
3.98
4.73
5.76
6.61
7.82
8.82
9.88
11
12.59
13.87
10-
day
4.48
5.34
6.48
7.42
8.76
9.86
11
12.22
13.92
15.29
20-
day
6.17
7.31
8.7
9.81
11.31
12.49
13.69
14.9
16.53
17.79
30-
day
7.7
9.08
10.64
11.85
13.46
14.69
15.9
17.1
18.66
19.82
45- 60-
day day
9.75 11.59
11.45 13.59
13.17 15.5
14.46 16.93
16.07 18.71
17.24 20.01
18.35 21.2
19.38 22.31
20.64 23.65
21.53 24.59
Estimates (in/hr)
4.19
4.91
5.47
6.16
6.68
7.18
7.67
8.3
0
3.42
4.02
4.5
5.08
5.52
5.95
6.38
6.93
0
2.3
2.77
3.14
3.61
3.97
4.33
4.68
5.16
0
1.41
1.74
2
2.35
2.62
2.9
3.19
3.59
0
0.82
1.02
1.18
1.4
1.58
1.76
1.96
2.24
0
0.59 0.36 0.21
0.73 0.45 0.26
0.84 0.52 0.3
1.01 0.62 0.36
1.14 0.7 0.41
1.28 0.79 0.46
1.44 0.89 0.51
1.65 1.03 0.59
000
0.13
0.16
0.18
0.22
0.25
0.28
0.32
0.37
0
0.07
0.09
0.11
0.13
0.14
0.16
0.18
0.21
0
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.11
0
0.03
0.03
0.04
0.05
0.05
0.06
0.07
0.07
0
0.02
0.03
0.03
0.04
0.04
0.05
0.05
0
0
0.02
0.02
0.02
0.02
0.03
0.03
0.03
0
0
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0.02 0.01
0.02 0.02
0 0
0 0
Date/time: Thu Jan 31 14:52:44 EST 2008
D-16
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: WEST VIRGINIA
Station: CHARLESTON WSFO AP
Lon(dd): -81.5914
Lat(dd): 38.3794
Elev(feet): 744
Date/time: Thu Jan 31 14:53:54 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.34
0.4
0.48
0.54
0.62
0.67
0.72
0.78
0.84
0.89
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
4.82
5.78
6.49
7.39
8.08
8.7
9.34
10.13
0
10- 15-
min min
0.53 0.65
0.63 0.77
0.75 0.92
0.83 1.03
0.94 1.17
1.02 1.26
1.09 1.36
1.16 1.44
1.24 1.55
1.3 1.62
30-
min
0.85
1.03
1.26
1.43
1.65
1.8
1.96
2.11
2.29
2.43
60-
min
1.04
1.26
1.58
1.81
2.13
2.38
2.62
2.86
3.17
3.42
120-
min
1.21
1.46
1.82
2.1
2.48
2.78
3.08
3.38
3.8
4.12
3-hr 6-hr
1.27 1.5
1.53 1.8
1.91 2.22
2.2 2.56
2.61 3.03
2.93 3.41
3.26 3.81
3.59 4.22
4.05 4.78
4.41 5.23
12-
hr
1.77
2.11
2.58
2.96
3.5
3.95
4.41
4.89
5.57
6.11
24-
hr
2.16
2.56
3.1
3.55
4.16
4.65
5.17
5.7
6.44
7.02
2-
day
2.58
3.06
3.66
4.15
4.82
5.35
5.89
6.45
7.21
7.79
4-
day
2.99
3.54
4.21
4.73
5.44
5.98
6.53
7.08
7.8
8.36
7-
day
3.6
4.25
4.97
5.54
6.27
6.82
7.37
7.9
8.58
9.08
10-
day
4.15
4.89
5.67
6.27
7.03
7.61
8.15
8.68
9.34
9.83
20-
day
5.8
6.79
7.77
8.5
9.42
10.09
10.71
11.3
12.02
12.52
30-
day
7.3
8.53
9.63
10.46
11.48
12.22
12.9
13.52
14.26
14.77
45- 60-
day day
9.32 11.24
10.85 13.04
12.13 14.46
13.08 15.51
14.23 16.76
15.05 17.64
15.78 18.42
16.44 19.11
17.22 19.91
17.74 20.45
Estimates (in/hr)
3.77 3.07
4.49 3.68
5.01 4.11
5.66 4.66
6.12 5.05
6.55 5.42
6.97 5.78
7.45 6.19
0 0
2.06
2.52
2.85
3.29
3.61
3.92
4.21
4.59
0
1.26
1.58
1.81
2.13
2.38
2.62
2.86
3.17
0
0.73
0.91
1.05
1.24
1.39
1.54
1.69
1.9
0
0.51 0.3
0.64 0.37
0.73 0.43
0.87 0.51
0.98 0.57
1.08 0.64
1.2 0.7
1.35 0.8
0 0
0.18
0.21
0.25
0.29
0.33
0.37
0.41
0.46
0
0.11
0.13
0.15
0.17
0.19
0.22
0.24
0.27
0
0.06
0.08
0.09
0.1
0.11
0.12
0.13
0.15
0
0.04
0.04
0.05
0.06
0.06
0.07
0.07
0.08
0
0.03
0.03
0.03
0.04
0.04
0.04
0.05
0.05
0
0.02
0.02
0.03
0.03
0.03
0.03
0.04
0
0
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0
0
0.01
0.01
0.01
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0 0
0 0
Date/time: Thu Jan 31 14:54:26 EST 2008
D-17
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: VIRGINIA
Station: WASHINGTON REAGAN AP
Lon(dd): -77.0342
Lat(dd): 38.865
Elev(feet): 22
Date/time: TueFeb 5 10:31:30 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.36
0.43
0.51
0.57
0.64
0.7
0.75
0.81
0.87
0.93
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.11
6.08
6.79
7.7
8.36
9.04
9.67
10.49
0
10-
min
0.57
0.68
0.81
0.91
1.02
1.11
1.2
1.28
1.38
1.46
15-
min
0.71
0.86
1.03
1.15
1.3
1.41
1.51
1.61
1.74
1.83
30-
min
0.97
1.18
1.46
1.66
1.92
2.12
2.31
2.51
2.77
2.97
60-
min
1.21
1.49
1.87
2.16
2.56
2.87
3.19
3.52
3.97
4.33
120-
min
1.41
1.71
2.17
2.52
3.02
3.43
3.85
4.3
4.93
5.44
3-hr
1.5
1.83
2.32
2.71
3.26
3.72
4.21
4.72
5.45
6.06
6-hr
1.84
2.23
2.81
3.29
4
4.61
5.26
5.97
7.01
7.89
12-hr
2.22
2.67
3.4
4.02
4.97
5.8
6.72
7.75
9.32
10.67
24-hr
2.57
3.11
4
4.78
5.98
7.04
8.24
9.61
11.71
13.55
2-
day
2.99
3.62
4.64
5.51
6.83
7.98
9.25
10.68
12.83
14.68
4-
day
3.33
4.02
5.14
6.1
7.55
8.8
10.2
11.75
14.08
16.08
7-
day
3.85
4.64
5.86
6.91
8.48
9.83
11.32
12.96
15.42
17.51
10-
day
4.41
5.29
6.61
7.71
9.31
10.65
12.11
13.67
15.98
17.89
20- 30- 45- 60-
day day day day
5.95 7.32 9.19 10.94
7.07 8.66 10.84 12.86
8.55 10.3 12.67 14.86
9.74 11.62 14.08 16.37
11.41 13.43 15.93 18.32
12.76 14.88 17.35 19.77
14.16 16.36 18.73 21.16
15.61 17.88 20.09 22.48
17.63 19.94 21.84 24.16
19.22 21.55 23.14 25.37
Estimates (in/hr)
4.09
4.87
5.43
6.13
6.67
7.18
7.66
8.29
0
3.43
4.11
4.58
5.18
5.62
6.05
6.45
6.96
0
2.37
2.92
3.32
3.84
4.24
4.63
5.02
5.54
0
1.49
1.87
2.16
2.56
2.87
3.19
3.52
3.97
0
0.86
1.08
1.26
1.51
1.71
1.93
2.15
2.46
0
0.61
0.77
0.9
1.09
1.24
1.4
1.57
1.82
0
0.37
0.47
0.55
0.67
0.77
0.88
1
1.17
0
0.22
0.28
0.33
0.41
0.48
0.56
0.64
0.77
0
0.13
0.17
0.2
0.25
0.29
0.34
0.4
0.49
0
0.08
0.1
0.11
0.14
0.17
0.19
0.22
0.27
0
0.04
0.05
0.06
0.08
0.09
0.11
0.12
0.15
0
0.03
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.05
0.06
0
0
0.01 0.01 0.01 0.01
0.02 0.01 0.01 0.01
0.02 0.02 0.01 0.01
0.02 0.02 0.01 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.02
0000
0000
Date/time: TueFeb 5 10:32:29 EST 2008
D-18
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: MARYLAND
Station: BALTIMORE WSO ARPT
Lon(dd): -76.6839
Lat(dd): 39.1722
Elev(feet): 147
Date/time: Thu Jan 31 14:47:48 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.34
0.41
0.49
0.55
0.62
0.67
0.72
0.77
0.83
0.88
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
4.93
5.87
6.55
7.4
8.04
8.66
9.25
10
0
10-
min
0.55
0.66
0.78
0.87
0.98
1.07
1.15
1.22
1.32
1.39
15-
min
0.69
0.83
0.99
1.1
1.25
1.35
1.45
1.54
1.66
1.74
30-
min
0.94
1.14
1.41
1.6
1.85
2.03
2.22
2.4
2.64
2.82
60-
min
1.17
1.43
1.8
2.08
2.46
2.76
3.06
3.37
3.79
4.11
120-
min
1.4
1.7
2.16
2.51
3
3.4
3.82
4.25
4.87
5.37
3-hr
1.51
1.83
2.33
2.71
3.27
3.72
4.2
4.71
5.45
6.04
6-hr
1.86
2.25
2.84
3.32
4.04
4.66
5.32
6.04
7.09
7.98
12-hr
2.25
2.72
3.46
4.09
5.06
5.91
6.86
7.92
9.53
10.93
24-hr
2.61
3.16
4.06
4.85
6.08
7.16
8.38
9.76
11.89
13.76
2-
day
3.03
3.66
4.7
5.59
6.92
8.09
9.39
10.84
13.02
14.9
4-
day
3.35
4.05
5.18
6.15
7.61
8.87
10.27
11.84
14.19
16.2
7-
day
3.89
4.68
5.92
6.98
8.56
9.92
11.42
13.08
15.55
17.66
10-
day
4.43
5.33
6.65
7.75
9.36
10.71
12.16
13.73
16.01
17.93
20- 30- 45- 60-
day day day day
5.99 7.39 9.31 11.09
7.12 8.75 10.98 13.05
8.61 10.4 12.83 15.07
9.81 11.73 14.26 16.61
11.5 13.57 16.14 18.58
12.86 15.04 17.56 20.05
14.26 16.53 18.96 21.45
15.73 18.05 20.33 22.79
17.76 20.14 22.11 24.49
19.36 21.75 23.43 25.71
Estimates (in/hr)
3.94
4.7
5.24
5.9
6.4
6.88
7.33
7.9
0
3.3
3.96
4.42
4.99
5.4
5.8
6.17
6.63
0
2.28
2.82
3.2
3.69
4.07
4.44
4.8
5.28
0
1.43
1.8
2.08
2.46
2.76
3.06
3.37
3.79
0
0.85
1.08
1.25
1.5
1.7
1.91
2.13
2.44
0
0.61
0.78
0.9
1.09
1.24
1.4
1.57
1.81
0
0.38
0.47
0.55
0.68
0.78
0.89
1.01
1.18
0
0.23
0.29
0.34
0.42
0.49
0.57
0.66
0.79
0
0.13
0.17
0.2
0.25
0.3
0.35
0.41
0.5
0
0.08
0.1
0.12
0.14
0.17
0.2
0.23
0.27
0
0.04
0.05
0.06
0.08
0.09
0.11
0.12
0.15
0
0.03
0.04
0.04
0.05
0.06
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.05
0.06
0
0
0.01 0.01 0.01 0.01
0.02 0.01 0.01 0.01
0.02 0.02 0.01 0.01
0.02 0.02 0.01 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.01
0.03 0.03 0.02 0.02
0000
0000
Date/time: Thu Jan 31 14:48:21 EST 2008
D-19
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: DELAWARE
Station: DOVER
Lon(dd): -75.5167
Lat(dd): 39.2583
Elev(feet): 0
Date/time: Thu Jan 31 14:45:28 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.35
0.42
0.49
0.55
0.62
0.67
0.72
0.77
0.82
0.87
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.02
5.87
6.59
7.4
8.04
8.65
9.19
9.85
0
10-
min
0.56
0.67
0.78
0.88
0.98
1.07
1.15
1.21
1.3
1.37
15-
min
0.7
0.84
0.99
1.11
1.25
1.35
1.45
1.53
1.64
1.72
30-
min
0.96
1.16
1.41
1.61
1.85
2.04
2.22
2.38
2.6
2.78
60-
min
1.2
1.46
1.8
2.09
2.46
2.76
3.05
3.35
3.73
4.05
120-
min
1.46
1.76
2.2
2.57
3.05
3.44
3.84
4.25
4.79
5.25
3-hr
1.58
1.92
2.39
2.81
3.35
3.81
4.27
4.76
5.42
5.98
6-hr
1.95
2.35
2.92
3.44
4.14
4.75
5.39
6.08
7.04
7.88
12-hr
2.36
2.83
3.54
4.21
5.15
6
6.91
7.92
9.38
10.71
24-hr
2.68
3.26
4.24
5.08
6.36
7.49
8.75
10.19
12.37
14.27
2-
day
3.09
3.76
4.89
5.85
7.32
8.59
10.01
11.62
14.04
16.15
4-
day
3.42
4.16
5.35
6.37
7.88
9.18
10.62
12.23
14.63
16.69
7-
day
3.98
4.8
6.08
7.17
8.77
10.14
11.64
13.29
15.74
17.81
10-
day
4.48
5.38
6.71
7.8
9.38
10.71
12.12
13.73
16.12
18.17
20- 30- 45- 60-
day day day day
6.05 7.49 9.51 11.39
7.2 8.87 11.22 13.41
8.71 10.57 13.14 15.51
9.93 11.91 14.61 17.08
11.63 13.75 16.54 19.07
13 15.2 18.01 20.54
14.43 16.67 19.44 21.93
15.9 18.18 20.84 23.26
17.96 20.2 22.65 24.93
19.6 21.78 24 26.12
Estimates (in/hr)
4.01
4.7
5.26
5.9
6.4
6.87
7.28
7.79
0
3.36
3.96
4.44
4.99
5.4
5.79
6.13
6.54
0
2.32
2.82
3.22
3.69
4.07
4.43
4.77
5.2
0
1.46
1.8
2.09
2.46
2.76
3.05
3.35
3.73
0
0.88
1.1
1.29
1.52
1.72
1.92
2.12
2.4
0
0.64
0.8
0.93
1.11
1.27
1.42
1.58
1.8
0
0.39
0.49
0.57
0.69
0.79
0.9
1.02
1.18
0
0.23
0.29
0.35
0.43
0.5
0.57
0.66
0.78
0
0.14
0.18
0.21
0.27
0.31
0.36
0.42
0.52
0
0.08
0.1
0.12
0.15
0.18
0.21
0.24
0.29
0
0.04
0.06
0.07
0.08
0.1
0.11
0.13
0.15
0
0.03
0.04
0.04
0.05
0.06
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.05
0.06
0.06
0
0.01 0.01 0.01 0.01
0.02 0.01 0.01 0.01
0.02 0.02 0.01 0.01
0.02 0.02 0.02 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.02
0.03 0.03 0.02 0.02
0000
0000
Date/time: Thu Jan 31 14:46:04 EST 2008
D-20
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: NEW JERSEY
Station: HIGHTSTOWN2W
Lon(dd): -74.5642
Lat(dd): 40.265
Elev(feet): 98
Date/time: Thu Jan 31 14:43:06 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.34
0.41
0.48
0.54
0.61
0.66
0.71
0.75
0.81
0.86
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
4.86
5.77
6.44
7.27
7.87
8.47
9.04
9.74
0
10-
min
0.54
0.65
0.77
0.86
0.96
1.04
1.12
1.19
1.28
1.35
15-
min
0.68
0.81
0.97
1.09
1.22
1.32
1.42
1.51
1.62
1.69
30-
min
0.93
1.12
1.38
1.57
1.81
1.99
2.17
2.35
2.57
2.74
60-
min
1.16
1.41
1.77
2.05
2.41
2.7
2.99
3.29
3.69
4
120-
min
1.41
1.72
2.18
2.54
3.03
3.42
3.83
4.25
4.84
5.31
3-hr
1.55
1.89
2.41
2.8
3.36
3.82
4.3
4.79
5.49
6.05
6-hr
1.97
2.39
3.03
3.55
4.3
4.93
5.6
6.33
7.38
8.26
12-hr
2.39
2.89
3.68
4.36
5.37
6.24
7.2
8.26
9.86
11.22
24-hr
2.73
3.31
4.26
5.07
6.3
7.37
8.57
9.9
11.93
13.69
2-
day
3.16
3.84
4.94
5.87
7.25
8.44
9.75
11.2
13.38
15.24
4-
day
3.55
4.3
5.46
6.44
7.86
9.06
10.37
11.79
13.88
15.65
7-
day
4.16
5
6.26
7.31
8.83
10.12
11.5
12.99
15.18
17
10-
day
4.73
5.67
6.99
8.06
9.6
10.87
12.21
13.63
15.66
17.39
20- 30- 45- 60-
day day day day
6.4 7.96 10.16 12.18
7.61 9.41 11.96 14.3
9.13 11.09 13.88 16.41
10.35 12.39 15.34 17.98
12.02 14.14 17.22 19.97
13.34 15.49 18.63 21.42
14.69 16.83 19.99 22.79
16.07 18.17 21.31 24.08
17.96 19.94 22.98 25.68
19.43 21.28 24.22 26.83
Estimates (in/hr)
3.89
4.62
5.15
5.79
6.27
6.73
7.16
7.7
0
3.26
3.9
4.34
4.89
5.29
5.67
6.02
6.46
0
2.25
2.77
3.15
3.62
3.98
4.34
4.69
5.14
0
1.41
1.77
2.05
2.41
2.7
2.99
3.29
3.69
0
0.86
1.09
1.27
1.51
1.71
1.92
2.13
2.42
0
0.63
0.8
0.93
1.12
1.27
1.43
1.6
1.83
0
0.4
0.51
0.59
0.72
0.82
0.94
1.06
1.23
0
0.24
0.31
0.36
0.45
0.52
0.6
0.69
0.82
0
0.14
0.18
0.21
0.26
0.31
0.36
0.41
0.5
0
0.08
0.1
0.12
0.15
0.18
0.2
0.23
0.28
0
0.04
0.06
0.07
0.08
0.09
0.11
0.12
0.14
0
0.03
0.04
0.04
0.05
0.06
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.05
0.05
0.06
0
0
0.02 0.01 0.01 0.01
0.02 0.02 0.01 0.01
0.02 0.02 0.01 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.02
0.03 0.03 0.02 0.02
0000
0000
Date/time: Thu Jan 31 14:43:54 EST 2008
D-21
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: TENNESSEE
Station: NASHVILLE WSO AIRPORT
Lon(dd): -86.6764
Lat(dd): 36.1253
Elev(feet): 498
Date/time: Thu Jan 31 14:41:00 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.38
0.45
0.51
0.57
0.64
0.69
0.74
0.78
0.84
0.89
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.35
6.17
6.82
7.63
8.24
8.83
9.41
10.12
0
10-
min
0.61
0.71
0.82
0.91
1.01
1.09
1.17
1.24
1.33
1.4
15-
min
0.76
0.9
1.04
1.15
1.28
1.39
1.48
1.57
1.68
1.75
30-
min
1.04
1.24
1.48
1.67
1.9
2.09
2.27
2.44
2.67
2.84
60-
min
1.3
1.55
1.9
2.17
2.54
2.83
3.12
3.42
3.83
4.15
120-
min
1.54
1.83
2.23
2.54
2.97
3.31
3.67
4.03
4.52
4.91
3-hr 6-hr
1.67 2
1.99 2.38
2.41 2.88
2.76 3.31
3.23 3.9
3.61 4.38
4.01 4.88
4.41 5.41
4.97 6.15
5.41 6.73
12-
hr
2.37
2.82
3.42
3.92
4.62
5.19
5.79
6.41
7.28
7.96
24-
hr
2.83
3.37
4.11
4.7
5.53
6.2
6.89
7.61
8.6
9.37
2-
day
3.37
4.03
4.92
5.65
6.69
7.53
8.41
9.34
10.63
11.65
4-
day
3.76
4.48
5.45
6.23
7.29
8.15
9.04
9.94
11.17
12.14
7-
day
4.56
5.44
6.62
7.58
8.93
10.01
11.15
12.34
13.99
15.31
10-
day
5.24
6.24
7.51
8.53
9.91
11.01
12.13
13.26
14.8
15.99
20-
day
7.08
8.39
9.9
11.05
12.56
13.7
14.82
15.91
17.31
18.35
30- 45- 60-
day day day
8.72 10.86 13.07
10.28 12.76 15.34
11.99 14.69 17.56
13.3 16.16 19.2
15.02 18.05 21.25
16.32 19.46 22.76
17.6 20.81 24.16
18.85 22.11 25.46
20.46 23.75 27.05
21.66 24.93 28.17
Estimates (in/hr)
4.28
4.94
5.45
6.08
6.56
7.02
7.46
8
0
3.59
4.16
4.6
5.14
5.54
5.92
6.27
6.71
0
2.48
2.96
3.33
3.81
4.17
4.53
4.88
5.34
0
1.55
1.9
2.17
2.54
2.83
3.12
3.42
3.83
0
0.91
1.11
1.27
1.48
1.66
1.83
2.01
2.26
0
0.66 0.4
0.8 0.48
0.92 0.55
1.08 0.65
1.2 0.73
1.33 0.82
1.47 0.9
1.66 1.03
0 0
0.23
0.28
0.33
0.38
0.43
0.48
0.53
0.6
0
0.14
0.17
0.2
0.23
0.26
0.29
0.32
0.36
0
0.08
0.1
0.12
0.14
0.16
0.18
0.19
0.22
0
0.05
0.06
0.06
0.08
0.08
0.09
0.1
0.12
0
0.03
0.04
0.05
0.05
0.06
0.07
0.07
0.08
0
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0
0
0.02
0.02
0.02
0.03
0.03
0.03
0.03
0
0
0.01 0.01 0.01
0.02 0.01 0.01
0.02 0.01 0.01
0.02 0.02 0.01
0.02 0.02 0.02
0.02 0.02 0.02
0.03 0.02 0.02
000
000
Date/time: Thu Jan 31 14:41:55 EST 2008
D-22
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: NORTH CAROLINA
Station: CHARLOTTE WSO ARPT
Lon(dd): -80.9542
Lat(dd): 35.2225
Elev(feet): 728
Date/time: Thu Jan 31 14:38:42 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.4
0.47
0.55
0.6
0.67
0.71
0.75
0.79
0.83
0.86
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.64
6.55
7.22
7.99
8.53
9.02
9.44
9.94
0
10-
min
0.63
0.75
0.88
0.96
1.06
1.13
1.19
1.25
1.31
1.35
15-
min
0.79
0.94
1.11
1.22
1.35
1.43
1.51
1.57
1.65
1.69
30-
min
1.09
1.3
1.57
1.77
1.99
2.16
2.31
2.45
2.62
2.74
60-
min
1.35
1.64
2.02
2.3
2.65
2.93
3.19
3.44
3.76
4
120-
min
1.57
1.9
2.36
2.71
3.16
3.51
3.85
4.19
4.64
4.97
3-hr 6-hr 1,2"
hr
1.68 2.03 2.41
2.02 2.45 2.91
2.52 3.06 3.64
2.91 3.54 4.23
3.44 4.19 5.04
3.85 4.7 5.69
4.27 5.23 6.36
4.7 5.77 7.06
5.29 6.52 8.04
5.75 7.11 8.82
24-
hr
2.77
3.34
4.19
4.86
5.76
6.48
7.22
7.97
9
9.8
2-
day
3.24
3.9
4.86
5.62
6.64
7.45
8.27
9.11
10.26
11.15
4-
day
3.63
4.36
5.37
6.18
7.28
8.15
9.04
9.95
11.2
12.16
7-
day
4.17
4.97
6.04
6.9
8.08
9.01
9.97
10.95
12.28
13.31
10-
day
4.78
5.69
6.83
7.73
8.94
9.89
10.85
11.82
13.12
14.13
20-
day
6.41
7.57
8.93
10.01
11.46
12.59
13.73
14.89
16.44
17.64
30-
day
7.92
9.31
10.82
11.99
13.53
14.72
15.9
17.07
18.62
19.8
45- 60-
day day
9.96 11.84
11.66 13.82
13.31 15.61
14.59 16.99
16.24 18.77
17.5 20.11
18.71 21.4
19.89 22.65
21.43 24.27
22.59 25.49
Estimates (in/hr)
4.51
5.25
5.78
6.37
6.8
7.16
7.49
7.86
0
3.78
4.43
4.87
5.38
5.74
6.04
6.3
6.59
0
2.61
3.14
3.53
3.99
4.32
4.62
4.9
5.25
0
1.64
2.02
2.3
2.65
2.93
3.19
3.44
3.76
0
0.95
1.18
1.35
1.58
1.75
1.93
2.1
2.32
0
0.67 0.41 0.24
0.84 0.51 0.3
0.97 0.59 0.35
1.14 0.7 0.42
1.28 0.79 0.47
1.42 0.87 0.53
1.57 0.96 0.59
1.76 1.09 0.67
000
0.14
0.17
0.2
0.24
0.27
0.3
0.33
0.38
0
0.08
0.1
0.12
0.14
0.16
0.17
0.19
0.21
0
0.05
0.06
0.06
0.08
0.08
0.09
0.1
0.12
0
0.03
0.04
0.04
0.05
0.05
0.06
0.07
0.07
0
0.02
0.03
0.03
0.04
0.04
0.05
0.05
0
0
0.02
0.02
0.02
0.02
0.03
0.03
0.03
0
0
0.01
0.02
0.02
0.02
0.02
0.02
0.02
0
0
0.01 0.01
0.01 0.01
0.01 0.01
0.02 0.01
0.02 0.01
0.02 0.01
0.02 0.02
0 0
0 0
Date/time: Thu Jan 31 14:39:36 EST 2008
D-23
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: SOUTH CAROLINA
Station: COLUMBIA WSFO AP
Lon(dd): -81.1219
Lat(dd): 33.9456
Elev(feet): 209
Date/time: Thu Jan 31 13:53:59 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.46
0.53
0.61
0.68
0.76
0.83
0.89
0.95
1.03
1.09
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
6.35
7.27
8.14
9.12
9.91
10.68
11.41
12.32
0
10-
min
0.73
0.85
0.97
1.08
1.21
1.32
1.41
1.51
1.62
1.72
15-
min
0.91
1.06
1.23
1.37
1.53
1.67
1.79
1.9
2.04
2.16
30-
min
1.25
1.47
1.75
1.99
2.27
2.51
2.74
2.96
3.25
3.5
60-
min
1.55
1.84
2.24
2.59
3.03
3.4
3.77
4.15
4.67
5.11
120-
min
1.79
2.14
2.61
3.05
3.62
4.11
4.62
5.16
5.91
6.56
3-hr
1.89
2.25
2.77
3.25
3.91
4.49
5.1
5.76
6.71
7.55
6-hr
2.24
2.67
3.27
3.85
4.64
5.35
6.1
6.92
8.09
9.14
12-hr
2.61
3.12
3.84
4.54
5.51
6.39
7.33
8.36
9.87
11.23
24-hr
3.02
3.62
4.52
5.28
6.39
7.33
8.35
9.46
11.1
12.47
2-
day
3.55
4.25
5.28
6.13
7.35
8.37
9.47
10.66
12.35
13.75
4-
day
4.02
4.82
5.93
6.84
8.13
9.19
10.31
11.5
13.21
14.59
7-
day
4.68
5.57
6.79
7.79
9.2
10.36
11.58
12.87
14.73
16.25
10-
day
5.32
6.31
7.61
8.68
10.18
11.39
12.66
13.99
15.89
17.43
20- 30- 45- 60-
day day day day
7.17 8.84 10.98 13.14
8.47 10.41 12.88 15.41
10.02 12.15 14.83 17.57
11.25 13.51 16.34 19.21
12.93 15.32 18.32 21.27
14.25 16.7 19.8 22.79
15.59 18.06 21.24 24.22
16.96 19.41 22.64 25.56
18.8 21.2 24.46 27.22
20.23 22.54 25.8 28.4
Estimates (in/hr)
5.08
5.83
6.5
7.27
7.9
8.48
9.05
9.74
0
4.25
4.91
5.48
6.14
6.66
7.15
7.61
8.18
0
2.94
3.49
3.97
4.55
5.02
5.48
5.92
6.51
0
1.84
2.24
2.59
3.03
3.4
3.77
4.15
4.67
0
1.07
1.3
1.52
1.81
2.06
2.31
2.58
2.95
0
0.75
0.92
1.08
1.3
1.49
1.7
1.92
2.23
0
0.45
0.55
0.64
0.78
0.89
1.02
1.16
1.35
0
0.26
0.32
0.38
0.46
0.53
0.61
0.69
0.82
0
0.15
0.19
0.22
0.27
0.31
0.35
0.39
0.46
0
0.09
0.11
0.13
0.15
0.17
0.2
0.22
0.26
0
0.05
0.06
0.07
0.08
0.1
0.11
0.12
0.14
0
0.03
0.04
0.05
0.05
0.06
0.07
0.08
0.09
0
0.03
0.03
0.04
0.04
0.05
0.05
0.06
0
0
0.02 0.01 0.01 0.01
0.02 0.02 0.01 0.01
0.02 0.02 0.02 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.02
0.03 0.03 0.02 0.02
0.04 0.03 0.02 0.02
0000
0000
Date/time: Thu Jan 31 13:54:39 EST 2008
D-24
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: PUERTO RICO
Station: SAN JUAN WSFO
Lon(dd): -66
Lat(dd): 18.4333
Elev(feet): 6
Date/time: Tue Feb 5 09:38:04 EST 2008
Freq (yr)
1
2
5
10
25
50
100
200
500
1000
5-min
0.37
0.46
0.52
0.55
0.6
0.63
0.66
0.69
0.72
0.74
Precipitation Intensity
2
5
10
25
50
100
200
500
1000
5.51
6.18
6.65
7.2
7.6
7.93
8.26
8.64
0
10-
min
0.51
0.63
0.7
0.76
0.82
0.86
0.9
0.94
0.98
1.01
15-
min
0.66
0.81
0.9
0.97
1.05
1.11
1.16
1.21
1.26
1.3
30-
min
1.05
1.29
1.45
1.56
1.69
1.78
1.86
1.93
2.02
2.09
60-
min
1.56
1.91
2.15
2.31
2.5
2.64
2.76
2.87
3
3.1
120-
min
1.87
2.34
2.7
2.94
3.24
3.45
3.64
3.83
4.06
4.22
3-hr
2
2.51
2.95
3.25
3.61
3.88
4.13
4.37
4.68
4.9
6-hr
2.48
3.15
3.89
4.42
5.08
5.58
6.06
6.54
7.17
7.64
12-hr
2.8
3.62
4.7
5.54
6.68
7.58
8.49
9.44
10.73
11.74
24-hr
3.27
4.26
5.66
6.76
8.29
9.5
10.75
12.04
13.83
15.24
2-
day
4
5.21
6.9
8.26
10.13
11.63
13.17
14.79
17.03
18.8
4-
day
4.44
5.75
7.61
9.11
11.2
12.88
14.6
16.42
18.96
20.97
7-
day
5.12
6.59
8.56
10.14
12.33
14.08
15.88
17.75
20.35
22.4
10-
day
5.75
7.35
9.32
10.9
13.05
14.76
16.5
18.28
20.73
22.65
20- 30- 45- 60-
day day day day
7.86 9.93 12.31 14.92
9.92 12.45 15.38 18.51
12.13 14.86 18.14 21.49
13.89 16.74 20.34 23.87
16.24 19.19 23.2 26.97
18.07 21.07 25.38 29.34
19.91 22.91 27.53 31.64
21.78 24.78 29.72 33.98
24.27 27.21 32.6 37.03
26.17 29.06 34.77 39.34
Estimates (in/hr)
3.77
4.22
4.54
4.93
5.19
5.42
5.64
5.9
0
3.22
3.62
3.89
4.21
4.44
4.64
4.83
5.05
0
2.58
2.89
3.11
3.37
3.56
3.72
3.86
4.04
0
1.91
2.15
2.31
2.5
2.64
2.76
2.87
3
0
1.17
1.35
1.47
1.62
1.72
1.82
1.91
2.03
0
0.84
0.98
1.08
1.2
1.29
1.37
1.45
1.56
0
0.53
0.65
0.74
0.85
0.93
1.01
1.09
1.2
0
0.3
0.39
0.46
0.55
0.63
0.71
0.78
0.89
0
0.18
0.24
0.28
0.35
0.4
0.45
0.5
0.58
0
0.11
0.14
0.17
0.21
0.24
0.27
0.31
0.35
0
0.06
0.08
0.09
0.12
0.13
0.15
0.17
0.2
0
0.04
0.05
0.06
0.07
0.08
0.09
0.11
0.12
0
0.03
0.04
0.05
0.05
0.06
0.07
0.08
0
0
0.02 0.02 0.01 0.01
0.03 0.02 0.02 0.01
0.03 0.02 0.02 0.02
0.03 0.03 0.02 0.02
0.04 0.03 0.02 0.02
0.04 0.03 0.03 0.02
0.05 0.03 0.03 0.02
0000
0000
Date/time: Tue Feb 5 09:39:39 EST 2008
D-25
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Precipitation frequency estimates (depth/inches)
Point Estimates
Data series: Partial duration maxima
State: DISTRICT OF COLUMBIA
Station: NATIONAL ARBORETUM WASHINGTON DC
Lon (dd):-76.97
Lat(dd): 38.9133
Elev(feet): 78
Date/time: Tue Feb 5 09:44:27 EST 2008
Freq (yr) 5-min
1 0.35
2 0.42
5 0.5
10 0.56
25 0.63
50 0.69
100 0.74
200 0.8
500 0.86
1000 0.91
Precipitation Intensity
2 5.05
5 6.01
10 6.72
25 7.61
50 8.27
100 8.92
200 9.54
500 10.33
1000 0
10-
min
0.56
0.67
0.8
0.9
1.01
1.1
1.18
1.26
1.36
1.44
15-
min
0.7
0.85
1.01
1.13
1.28
1.39
1.49
1.59
1.72
1.8
30-
min
0.96
1.17
1.44
1.64
1.9
2.09
2.29
2.48
2.73
2.92
60-
min
1.2
1.47
1.85
2.14
2.52
2.83
3.15
3.47
3.92
4.26
120-
min
1.41
1.71
2.17
2.52
3.02
3.42
3.84
4.28
4.91
5.42
3-hr
1.51
1.83
2.33
2.72
3.27
3.73
4.22
4.73
5.47
6.07
6-hr
1.85
2.25
2.84
3.32
4.04
4.65
5.32
6.03
7.09
7.98
12-hr
2.25
2.71
3.44
4.08
5.04
5.89
6.83
7.87
9.47
10.86
24-hr
2.61
3.16
4.06
4.85
6.07
7.15
8.37
9.76
11.9
13.78
2-
day
3.03
3.67
4.7
5.59
6.93
8.09
9.39
10.84
13.03
14.91
4-
day
3.37
4.07
5.2
6.18
7.64
8.91
10.32
11.9
14.26
16.3
7-
day
3.91
4.7
5.94
7.01
8.6
9.96
11.48
13.15
15.65
17.79
10-
day
4.46
5.35
6.68
7.8
9.42
10.78
12.25
13.84
16.16
18.1
20-
day
6.02
7.16
8.65
9.86
11.55
12.92
14.33
15.8
17.85
19.47
30- 45- 60-
day day day
7.42 9.32 11.09
8.77 10.99 13.04
10.43 12.84 15.07
11.77 14.27 16.6
13.62 16.15 18.58
15.09 17.58 20.05
16.59 18.99 21.46
18.12 20.37 22.81
20.23 22.16 24.52
21.87 23.48 25.76
Estimates (in/hr)
4.04
4.81
5.37
6.06
6.58
7.09
7.56
8.17
0
3.38
4.06
4.53
5.12
5.56
5.97
6.36
6.86
0
2.34
2.88
3.28
3.79
4.18
4.57
4.95
5.46
0
1.47
1.85
2.14
2.52
2.83
3.15
3.47
3.92
0
0.86
1.08
1.26
1.51
1.71
1.92
2.14
2.46
0
0.61
0.77
0.9
1.09
1.24
1.4
1.58
1.82
0
0.37
0.47
0.55
0.68
0.78
0.89
1.01
1.18
0
0.23
0.29
0.34
0.42
0.49
0.57
0.65
0.79
0
0.13
0.17
0.2
0.25
0.3
0.35
0.41
0.5
0
0.08
0.1
0.12
0.14
0.17
0.2
0.23
0.27
0
0.04
0.05
0.06
0.08
0.09
0.11
0.12
0.15
0
0.03
0.04
0.04
0.05
0.06
0.07
0.08
0.09
0
0.02
0.03
0.03
0.04
0.04
0.05
0.06
0
0
0.01
0.02
0.02
0.02
0.03
0.03
0.03
0
0
0.01 0.01 0.01
0.01 0.01 0.01
0.02 0.01 0.01
0.02 0.01 0.01
0.02 0.02 0.01
0.02 0.02 0.01
0.03 0.02 0.02
000
000
Date/time: Tue Feb 5 09:45:19 EST 2008
D-26
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
ATLAS 2. Volum* 1
Notional QcrtriK ainl Atino-ipherlt Adminnli
Nation*! Wenlhep Service, Of lie* of Hydroloi)
Prtpatcd lur U.S D«pwlnwnt of Africulturi,
Soil COOMnMon Scfvle», EntfnMriiu D.VISMSI
ISOPLUVIALS OF 2-YR 24-HR PRECIPITATION
IN TENTHS OF AN INCH
Figure D-6. NOAA Atlas 2 - Montana - Isopluvials of 2-year, 24-hour precipitation in tenths of an inch.
D-27
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
10-YEAR 6-HOUR RAINFALL (INCHES)
Figure D-7. Technical Paper No. 40 Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and Return
Periods from 1 to 100 Years - 10-Year, 6-Hour Rainfall (inches).
D-28
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Table D-4. Atlas 2 and Technical Paper Map Results
State
Alabama
Arkansas
California
Colorado
Connecticut
Florida
Georgia
Hawaii
Idaho
Iowa
Kansas
Louisiana
Maine
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
New Hampshire
New York
North Dakota
Oklahoma
Oregon
Rhode Island
South Dakota
Texas
Indicator city
Montgomery
Little Rock
Sacramento
Denver
Hartford
Tallahassee
Atlanta
Honolulu
Boise
Des Moines
Kansas City
Baton Rouge
Augusta
Boston
Lansing
St. Paul
Jackson
Kansas City
Helena
Lincoln
Manchester
Albany
Bismarck
Oklahoma City
Salem
Providence
Pierre
Fort Worth
2-year, 24-hour storm
Depth
(inches)
4.50
4.10
2.00
2.00
3.10
4.75
3.70
4.75
1.20
3.25
3.50
5.25
2.80
3.10
2.40
2.75
4.45
3.45
1.30
3.00
2.80
2.90
1.90
3.70
2.50
3.20
2.25
3.90
Intensity
(inches/hr)
0.19
0.17
0.08
0.08
0.13
0.20
0.15
0.20
0.05
0.14
0.15
0.22
0.12
0.13
0.10
0.11
0.19
0.14
0.05
0.13
0.12
0.12
0.08
0.15
0.10
0.13
0.09
0.16
10-year, 24-hour storm
Depth
(inches)
6.5
6.05
o
J
3
4.8
7.4
5.5
7.8
1.8
4.7
5.2
8.2
4.25
4.5
3.6
4.2
6.7
5.3
2.1
4.8
4.3
4
3.25
5.8
3.5
4.8
3.5
6.3
Intensity
(inches/hr)
0.27
0.25
0.13
0.13
0.2
0.31
0.23
0.33
0.08
0.2
0.22
0.34
0.18
0.19
0.15
0.18
0.28
0.22
0.09
0.2
0.18
0.17
0.14
0.24
0.15
0.2
0.15
0.26
25-year, 24-hour storm
Depth
(inches)
7.6
7
3.5
3.8
5.5
8.5
6.5
8.9
2.2
5.5
6.1
9.1
4.9
5.5
4.2
4.7
7.8
6
2.4
5.4
5
5.9
3.75
6.9
4
5.7
4.1
7.4
Intensity
(inches/hr)
0.32
0.29
0.15
0.16
0.23
0.35
0.27
0.37
0.09
0.23
0.25
0.38
0.2
0.23
0.18
0.2
0.33
0.25
0.1
0.23
0.21
0.25
0.16
0.29
0.17
0.24
0.17
0.31
10-year, 6 hour storm
Depth
(inches)
4.60
4.35
1.70
2.30
3.25
5.25
4.20
4.80
1.20
3.54
3.90
5.75
2.90
3.30
2.70
3.10
4.70
3.85
1.10
3.52
3.20
3.10
2.50
4.25
2.90
3.40
2.75
4.55
Intensity
(inches/hr)
0.77
0.73
0.28
0.38
0.54
0.88
0.70
0.80
0.20
0.59
0.65
0.96
0.48
0.55
0.45
0.52
0.78
0.64
0.18
0.59
0.53
0.52
0.42
0.71
0.48
0.57
0.46
0.76
D-29
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
State
Vermont
Washington
Wisconsin
Wyoming
Indicator city
Montpelier
Seattle
Madison
Cheyenne
2-year, 24-hour storm
Depth
(inches)
2.40
2.00
2.80
1.60
Intensity
(inches/hr)
0.10
0.08
0.12
0.07
10-year, 24-hour storm
Depth
(inches)
3.7
3
4.1
2.4
Intensity
(inches/hr)
0.15
0.13
0.17
0.1
25-year, 24-hour storm
Depth
(inches)
4.25
3.4
4.75
2.8
Intensity
(inches/hr)
0.18
0.14
0.2
0.12
10-year, 6 hour storm
Depth
(inches)
2.70
1.40
3.15
1.90
Intensity
(inches/hr)
0.45
0.23
0.53
0.32
D-30
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Sources: PRISM, Oregon State University, http://mole.nacse.org/prism/nn/index.phtml; PRISM
data sets were developed through projects funded partly by the USD A Natural Resources
Conservation Service, USDA Forest Service, NOAA Office of Global Programs, and others.
Class/Location and Latitude/Longitude Sources: USGS Geographic Names Information
System (GNIS) http://geonames.usgs.gov/pls/gnispublic/, and National Oceanic and
Atmospheric Administration (NOAA) National Weather Service (NWS) Precipitation Frequency
Data Server (PFDS) Atlas 14 http://hdsc.nws.noaa.gov/hdsc/pfds/.
PRISM Data Variables:
Parameter: Annual Precipitation
Start year: 1895
Stop year: 2007
Units: inches
Table D-5. Average Annual Precipitation Data (1895 to 2007)
Indicator city, state
Montgomery, Alabama
Phoenix, Arizona
Little Rock, Arkansas
Sacramento, California
Denver, Colorado
Hartford, Connecticut
Dover, Delaware
Tallahassee, Florida
Atlanta, Georgia
Boise, Idaho
Chicago, Illinois
Indianapolis, Indiana
Des Moines, Iowa
Kansas City, Kansas
Frankfort, Kentucky
Baton Rouge, Louisiana
Augusta, Maine
Baltimore, Maryland
Boston, Massachusetts
Lansing, Michigan
Saint Paul, Minnesota
lackson, Mississippi
Helena, Montana
USGS class location
(e.g., Populated Place)
OR
NOAA NWS Precipitation Frequency
Data Server Atlas 14 site location (e.g.,
WSO ARP)
Montgomery Populated Place (165344)
Phoenix WSFO AP, AZ (02-6481)
Little Rock Populated Place (83350)
Sacramento Populated Place (1659564)
Denver Populated Place (201738)
Hartford Populated Place (213160)
Dover, Delaware (07-2730)
Tallahassee Populated Place (308416)
Atlanta Populated Place (351615)
Boise Populated Place (400590)
Chicago O'Hare WSO ARP, IL (1 1-1549)
Indianapolis WSFO AP, IN (12-4259)
Des Moines Populated Place (465961)
Kansas City Populated Place (478635)
Frankfort Lock 4, KY (15-3028)
Baton Rouge Populated Place (1629914)
Augusta Populated Place (581636)
Baltimore WSO AP, MD (18-0465)
Boston Populated Place (617565)
Lansing Populated Place (1625035)
Saint Paul Populated Place (66285 1)
lackson Populated Place (71 1543)
Helena Populated Place (8021 16)
Latitude
(Northing)
32.3668
33.443
34.7464
38.5815
39.7391
41.7637
39.2583
30.4382
33.7489
43.6135
41.986
39.7317
41.6005
39.1141
38.235
30.4507
44.3106
39.1722
42.3584
42.7325
44.9444
32.2987
46.5927
Longitude
(Westing)
-86.2999
-111.99
-92.2895
-121.494
-104.984
-72.685
-75.516
-84.2807
-84.3879
-116.203
-87.9142
-86.2789
-93.6091
-94.6274
-84.8817
-91.1545
-69.7794
-76.6839
-71.0597
-84.5555
-93.0932
-90.1848
-112.036
Average
precipitation
(inches)
49.04
7.74
47.62
18.39
13.31
44.41
43.02
62.01
50.86
11.33
33.04
39.69
31.66
36.69
45.01
58.77
41.67
42.28
42.40
30.28
28.76
52.48
11.78
D-31
-------
Appendix D: Precipitation Data Representative of Major U.S. Metropolitan Areas
Indicator city, state
Lincoln, Nebraska
Las Vegas, Nevada
Manchester, New
Hampshire
Hightstown, New Jersey
Santa Fe, New Mexico
Albany, New York
Charlotte, North Carolina
Bismarck, North Dakota
Columbus, Ohio
Oklahoma City, Oklahoma
Salem, Oregon
Philadelphia, Pennsylvania
Providence, Rhode Island
Columbia, South Carolina
Pierre, South Dakota
Nashville, Tennessee
Fort Worth, Texas
Salt Lake City, Utah
Montpelier, Vermont
Arlington, Virginia
Seattle, Washington
Charleston, West Virginia
Madison, Wisconsin
Cheyenne, Wyoming
District of Columbia
USGS class location
(e.g., Populated Place)
OR
NOAA NWS Precipitation Frequency
Data Server Atlas 14 site location (e.g.,
WSO ARP)
Lincoln Populated Place (837279)
Las Vegas WSO Airport, NV (26-4436)
Manchester Populated Place (868243)
Hightstown 2 W, NJ (28-395 1)
Santa Fe, NM (29-8072)
Albany Populated Place (977310)
Charlotte WSO ARPT, NC (3 1-1690)
Bismarck Populated Place (1035849)
Columbus WSO Airport, OH (33-1786)
Oklahoma City Populated Place
(1102140)
Salem Populated Place (1 167861)
Philadelphia WSO AP, PA (36-6889)
Providence Populated Place (1219851)
Columbia WSFO AP, SC (38-1939)
Pierre Populated Place (1266887)
Nashville WSO Airport, TN (40-6402)
Fort Worth Populated Place (1380947)
Salt Lake City NWSFO, UT (42-7598)
Montpelier Populated Place (1461834)
Washington Reagan AP (44-8906)
Seattle Populated Place (1512650)
Charleston WSFO AP, WV (46-1570)
Madison Populated Place (1581834)
Cheyenne Populated Place (1609077)
National Arboretum DC (18-6350)
Latitude
(Northing)
40.8
36.0833
42.9956
40.265
35.6833
42.6525
35.2225
46.8083
39.9914
35.4675
44.9428
39.8683
41.8239
33.9456
44.3683
36.1253
32.7254
40.7725
44.26
38.865
47.6062
38.3794
43.073
41.1399
38.9133
Longitude
(Westing)
-96.6669
-115.166
-71.4547
-74.5642
-105.9
-73.7562
-80.9542
-100.783
-82.8808
-97.5164
-123.035
-75.2311
-71.4128
-81.1219
-100.35
-86.6764
-97.3208
-111.955
-72.5753
-77.0342
-122.332
-81.5914
-89.4012
-104.82
-76.97
Average
precipitation
(inches)
28.31
3.82
40.23
47.00
15.46
36.91
43.19
16.09
37.79
32.81
40.72
41.62
44.74
45.45
16.10
46.11
32.52
14.56
34.00
40.35
35.26
42.82
31.47
14.74
41.74
D-32
-------
Appendix E
Determination of Development Rates in U.S. Watersheds
-------
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
Land Use Data Sources
There are multiple sources of land cover change information at a national scale. The U.S.
Environmental Protection Agency (EPA) initially reviewed the U.S. Department of Agriculture
(USDA) National Resources Inventory (NRI). The NRI is a publicly available data set that tracks
temporal changes in major land covers within the United States using a sampling method. NRI
data is available for the entire United States on an 8-digit hydrologic unit basis (hydrologic units1
or HUCs) for the years 1982, 1987, 1992, and 1997. Data from these years are comparable and
can be used for analyzing land cover change at several broad scales. Data from NRI are also
available for the years 2001, 2002, and 2003, though not on an HUC basis. Data from these years
are available only at the major river basin level, and are not directly comparable to data from
earlier years because of changes in statistical and sampling methodologies.
The U.S. Geological Survey (USGS) National Land Cover Dataset (NLCD) provides another
national source of data on land cover change. The Multi-Resolution Land Characteristics
Consortium (MRLC) has produced the NLCD data sets that are based on classification of 30-
meter pixel resolution Landsat ETM+ (TM) satellite imagery. NLCD data is publicly available
for the years 1992 and 2001.2 Because new developments in mapping methodology, new
sources of input data, and changes in the mapping legend for the 2001 National Land Cover
Database (NLCD 2001) confound direct comparison between NLCD 2001 and the 1992 National
Land Cover Dataset (NLCD 1992), USGS prepared and recently released the NLCD 1992/2001
Retrofit Land Cover Change Product. The NLCD 1992/2001 Retrofit Land Cover Change
Product was developed to offer more accurate direct change analysis between the two products.
The NLCD 1992/2001 Retrofit Land Cover Change Product uses a specially developed
methodology to provide land cover change information at the Anderson Level I classification
scale,3 relying on decision tree classification of Landsat imagery from 1992 and 2001. While
NLCD 1992 reported on developed land in the categories of low-intensity residential, high-
intensity residential, commercial/industrial/transportation, and urban/recreational grasses, NLCD
2001 reported categories of developed low, medium, high, and open space. To compare change
between the two data sets, the developed categories were merged into one overall urban class.
Unchanged pixels between the two dates are coded with the NLCD 2001 Anderson Level I class
code, while changed pixels are labeled with afrom-to land cover change value. Modified
Anderson Level I Classifications include the following:
Open water
Urban
Barren
Forest
Grassland/Shrub
Agriculture
Wetlands Ice/Snow
1 For definitions of hydrologic units, see http://water.usgs.gov/GIS/huc.html.
2 To obtain data and for further descriptions of NLCD products, see http://www.mrlc.gov/index.asp.
3 See http://landcover.usgs.gov/pdf/anderson.pdf
E-l
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
The NLCD 1992/2001 Retrofit Land Cover Change Product was intended to provide a current,
consistent, and seamless data set for the United States at medium spatial resolution for Anderson
Level I classes. This land cover change map and all documents pertaining to it are considered
provisional until a formal accuracy assessment can be conducted. Detailed definitions and
discussion of the NLCD 1992/2001 Retrofit Land Cover Change Product will be provided in an
upcoming paper.4
Watershed Boundary Data Sources
HUC boundaries encompass surface water drainage to an outlet and are useful units for
summarization of land cover change information. HUCs through four levels were created in the
1970s as the USGS developed a hierarchical HUC that divides the country into 21 regions, 222
subregions, 352 accounting units, and 2,149 cataloging units on the basis of surface hydrologic
features. The 8-digit HUC, or cataloging unit (now referred to as a basin)., is approximately
448,000 acres. By the 1990s, geographic information system (GIS) tools facilitated the mapping
of digital HUC boundaries and the Natural Resources Conservation Service started to delineate
HUCs to the 5th and 6th level by using GIS to meet 1:24,000 National Map Accuracy Standards.
With increased interest from other federal, state, and local entities, this initiative became an
interagency effort to create the Watershed Boundary Dataset (WBD) as a hydrologically correct,
seamless, and consistent national GIS database. The new levels are called watershed (5th level,
10-digit) and subwatershed (6th level, 12-digit). The watershed level is typically 40,000 to
250,000 acres, and the subwatershed level is typically 10,000 to 40,000 acres. An estimated
22,000 watersheds and 160,000 subwatersheds will be mapped to the 5th and 6th level when the
data set is complete.
The WBD provides publicly available spatial data for watershed boundaries at various scales
within the United States. Attachment A shows the status of the WBD for the nation as of April
28, 2008. EPA is working to certify 10- and 12-digit HUC boundaries for the remainder of the
country. Because the WBD is not complete, and because the water quality model used by EPA
(SPARROW) does not operate on HUC boundaries, EPA chose not to characterize land use
change on a HUC basis.
Another option for summarizing national land cover change in drainage area units is to use a
coarser USGS data set than the WBD. A consistent, national scale watershed data set was
prepared to match the Reach File Version 1.0 (RF1) hydrology data set, a vector database used
extensively by EPA and states to model approximately 700,000 miles of streams and open waters
in the conterminous United States. This watershed data set, the Enhanced River Reach File 1.2
(ERF1_2), was designed to be a digital database of river reaches capable of supporting regional
and national water-quality and river-flow modeling.5 The ERF1_2 coverage extends the earlier
drainage area founded on the 1-kilometer data for North America.6 ERF1_2 contains 67,171
watersheds with a minimum size of 247 acres (1 km2) and an average size of 30,182 acres (122
4 Coan, M, Fry, I, Homer, C., Meyer D. K., Larson, C., and J. Wickham. In Progress. Completion of the National
Land Cover Database 1992/2001 Change Product.
5 Further information on ERF1_2 watersheds is at http://water.usgs.gov/GIS/metadata/usgswrd/XML/erfl_2.xml.
6 Verdin, K.L., and S.K. Jenson. 1996. Development of continental scale digital elevation models and extraction of
hydrographic features. In Proceedings of the Third International Conference/Workshop on Integrating GIS and
Environmental Modeling. CD-ROM. Santa Fe, NM.
E-2
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Appendix E: Determination of Development Rates in U.S. Watersheds
km2). (See DCN 43097 in the Administrative Record for an index of the spatial data analyses
conducted for the proposed rule.
Analysis
EPA prepared spreadsheets summarizing the amount of acreage changing from undeveloped land
to developed land within each state and ERF1_2 watershed of the United States by aggregating
land cover change estimates from the NLCD 1992/2001 Retrofit Land Cover Change Product on
an ERF1_2 level. Figure 1 shows an example of the Retrofit Land Cover Change Product near an
urban area.
0 65 130 Miles
Legend ~T~
] RF1 watershed
1992-2001 Change Data
| Change to Urban
NLCD Class
Modified Anderson
^J Agriculture
I I Barren
~^\ Forest
^ Grassland/Shrub
^j Ice/Snow
~^\ Open Water
| | Urban
I I Wetlands
Figure E-l. NLCD 1992/2001 Retrofit Land Cover Change
Product near Seattle, Washington.
Attachment B provides processing notes for the NLCD 1992/2001 Retrofit data analysis run by
EPA. This data was combined with EPA Region boundaries by spatially joining the National
Atlas State coverage7 attributed with EPA Region borders and the ERF1_2 watersheds. EPA
Regional boundaries were thus joined to ERF1_2 watershed so that developed areas within each
region could be identified. Representative urban areas describing the fastest developing and
greatest land area developing between 1992 and 2001 in a watershed are shown in Table E-l and
Figure E-2.
7 http://www.nationalatlas.gov/mld/statesp.html
E-:
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
Table E-l. Fastest Developing Watersheds by
Representative Urban Area per EPA Region
EPA Region
1
2
3
4
5
6
7
8
9
10
Indicator cities
Manchester, NH
Albany, NY
Washington, DC, VA, MD
Atlanta, GA
Chicago, IL IN
Dallas, Fort Worth, and Arlington, TX
Kansas City, MO and KS
Denver and Aurora, CO
Las Vegas, NV
Boise City, ID
Seattle, WA
Manchester,
Boise City,
ID
10
jjA/ashmgtp'n,
DC-VA^MD
Chicago,
IL--IN
Denver-
Aurora. CO
Kansas City.
MO--KS *
Las Vegas,
NV
Atlanta, GA
*
Dallas-Fort Worth-
Arlington, TX
Figure E-2. Urban Areas Selected for Each EPA Region.
After representative urban area watersheds were targeted, the ERF1_2 watershed summarizations
were also aggregated by state. When summarizing by state, an approach was needed to apportion
partial watersheds (those crossing state boundaries) into state aggregations. Allocation of
developed acreage within ERF1_2 watersheds overlapping state boundaries was done using a
basic area-weighting approach.
Table E-2 shows a national overview of developed acreage according to data source. Attachment
C presents state level results for developed acreage change in each ERF1_2 watershed.
E-4
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
Table E-2. National Change in Developed Acreage (1992-2001)
Source
NLCD RETROFIT
State aggregated NLCD RETROFIT
ERF 1 2 watersheds
NLCD (original)
NRI
1992
(million acres)
96.8
96.5
40.3
87
2001
(million acres)
102.1
101.8
101.3
106.3
Attachment A. Status of Watershed Boundary Data Set
NATURAL RESOURCES CONSERVATION SERVICE
WATERSHED BOUNDARY DATASET (WBD) STATUS
Status as of April 28, 2008
I I Not Started
I | in Progress
ending Certification
I [Certified*
certiirea oil 11 aatewde baste
(intrastale) until cross state (interstate)
u.iiit
E-5
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Appendix E: Determination of Development Rates in U.S. Watersheds
Attachment B. NLCD 1992-2001 Land-cover Change Estimates Processing Notes
J. Wickham and T. Wade (EPA/ORD/NERL/ESD/LEB)
02/08/2008
Grabbed erf file from water.usgs.gov/gis site
61,215 watersheds in erfl_2ws_lg (61215 records in vat)
1186 single pixel watersheds
67,172 polygons in vector version
Frequency of vector version returns 61215 unique values of grid_code
Projected into albers
67171 polygons in albers version
61214 unique grid-codes
5957 multi-part polygons
WS is used throughout as an acronym for watershed; WS is also equivalent to grid-code.
US was split into 8 regions to estimate changes (nwl, nw2, nel, ne2, swl, sw2, sel, se2)
changes were compiled into master file using
$llcclass = <>lcclass + $llcclass where $1 = masterfile and <> = the
regional files the equation sums watersheds that were split across regions. Areas were summed
then converted to percentages. The attribute labeled area was used to convert to percentages.
47 watersheds split across regions.
8562 9124 14264 14776 14857 15006 15324 16331 18374 23999 24000 24242 25213 25230
26327 26371 28767 30796 30816 31089 31378 33206 35283 36052 38432 38460 38550 38598
39269 39841 41670 41698 41758 42307 42309 42697 42712 42817 42831 43718 58938 58994
5900280951 81729
8 WS outside US
grid-code 95005 completely outside US (in CA west of ME)
grid-code 32171 completely outside US (in CA Nrth of MT)
others 31486 31534, 31535, 35239,35276, 42648
These WS have a -1 for LA01 and LA92 (explained below).
82 watersheds (grid-codes) in water; no land change estimates
1671 1762 1917 1918 4439 4440 4454 4455 10527 11764 11765 11766 11973 12181 12384
12440 12553 12555 18003 18014 19055 21249 21251 22621 22728 22793 22821 22854 26515
29044 29059 29063 29072 29261 32037 32051 32102 32108 32136 34650 34664 34665 34666
34787 34810 34811 34814 34818 38005 38051 38053 38154 38266 38816 38817 38818 38819
38820 38821 38975 40981 41030 42294 44296 45535 46510 46544 56786 57091 57095 57211
57427 57428 57526 57685 57689 57696 60232 65001 65002 80886 81545
Attributes LA92 and LA01 = land area in watershed for 1992 and 2001, respectively. Large
changes in the amount of water will cause anomalies in the percentage differences. For example,
WS 26515 in north central Missouri went from ag to water. It's a small (lkmA2) WS. These
E-6
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
anomalies will be common on the coast, and otherwise spread throughout were the small (i.e.,
lkmA2) WS overlay such changes. WS 81555 is a coastal example at the mouth of the Miss. R.
The attribute Dwatpct was added as a flag for changing amounts of water. It was calculated as ((
LA01 - LA92 ) / area ) * 100. The max value of Dwatpct is 67 percent in WS = 56768. The
change is due to sedimentation of a reservoir in the PNW. There are 191 WS with Dwatpct >= 5
percent.
Attachment C. State Level Results for NLCD Developed Acreage Change in Each
Watershed
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New lersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
1992DevAcre
2,066,843
1,285,258
1,836,496
6,278,143
1,609,387
727,078
113,052
26,381
4,526,626
3,026,921
847,520
4,014,480
2,238,170
2,527,225
2,463,194
1,740,669
1,788,423
653,697
698,386
1,174,234
3,746,569
2,648,001
1,721,138
2,845,661
1,187,901
1,699,570
572,706
426,786
1,124,705
799,207
2,682,301
2,816,229
1,667,029
3,549,025
2,387,508
1,552,824
2001DevAcre
2,197,370
1,407,907
1,912,867
6,524,934
1,751,860
736,131
120,552
26,973
4,869,204
3,320,243
898,587
4,198,994
2,349,522
2,618,075
2,666,039
1,830,453
1,904,013
694,157
757,203
1,204,116
3,949,025
2,731,981
1,827,846
2,967,610
1,246,005
1,754,268
646,109
442,861
1,163,128
841,237
2,751,793
2,984,873
1,725,866
3,705,609
2,538,082
1,618,391
Development rate
14,503
13,628
8,486
27,421
15,830
1,006
833
66
38,064
32,591
5,674
20,502
12,372
10,094
22,538
9,976
12,843
4,496
6,535
3,320
22,495
9,331
11,856
13,550
6,456
6,078
8,156
1,786
4,269
4,670
7,721
18,738
6,537
17,398
16,730
7,285
E-7
-------
Appendix E: Determination of Development Rates in U.S. Watersheds
State
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
State aggregated totals
1992DevAcre
3,006,384
173,764
1,487,194
1,315,111
2,189,700
8,229,892
758,031
304,570
1,818,500
2,286,574
1,016,805
2,345,956
491,168
96,492,992
2001DevAcre
3,150,410
177,161
1,632,717
1,389,905
2,307,498
8,781,625
833,531
309,695
1,954,814
2,401,699
1,048,419
2,414,075
516,758
101,802,191
Development rate
16,003
377
16,169
8,310
13,089
61,304
8,389
569
15,146
12,792
3,513
7,569
2,843
589,911
E-S
-------
Appendix F
Evaluating Soil Nature and Soil Erosion Representative of Major U.S.
Metropolitan Areas
-------
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Background and Purpose
To assess the pollutant loading reductions of potential regulatory options for the construction and
development (C&D) industry, the U.S. Environmental Protection Agency (EPA) developed a
series of model construction sites. By using estimates of regional soil erosion rates and pollutant
removal efficiencies for various regulatory options EPA estimated pollutant removals at the
national, state, and Reach File Version 1.0 (RF1) level. This appendix describes the soils data
collected and analyzed by EPA.
Methodology
Identification of Indicator Cities for Each Region
Because of the large variation in soil types and rainfall patterns nationwide, EPA selected high-
growth urban areas that could be used to produce representative point estimates. Using the
greatest rate of development, EPA identified major metropolitan areas within each of the 10 EPA
Regions to serve as indicators (see Appendix E). The indicator cites selected for the 10 EPA
Regions are provided in Table F-l. As noted in Table F-l, each indicator city actually represents
an area that might extend across state boundaries and includes surrounding suburban areas and
satellite towns/cities.
Note, two indicator cities were evaluated for EPA Region 10, in part to assess expected
variability in rainfall between damp coastal areas (e.g., Seattle) and the arid inland western flank
of the Rocky Mountains (e.g., Boise, Idaho).
Table F-2. EPA Region Indicator Cities and Associated High-Growth Metropolitan Areas
EPA
Region
1
2
3
4
5
6
7
8
9
10
10
Indicator city
Manchester, NH
Albany, NY
Washington, DC
Atlanta, GA
Chicago, IL
Dallas, TX
Kansas City, MO
Denver, CO
Las Vegas, NV
Boise City, ID
Seattle, WA
High-growth metropolitan area
Manchester, Concord and adjacent suburban communities
Albany, Schenectady, and adjacent suburban communities
Washington and adjacent communities in Virginia and Maryland
Atlanta and adjacent suburban communities
Chicago, and adjacent communities in Illinois and Indiana
Dallas, Fort Worth, and Arlington
Kansas City, adjacent suburban communities in Missouri and Kansas
Denver and adjacent suburban communities including Aurora
Las Vegas and adjacent suburban communities
Boise City and adjacent suburban communities
Seattle, Olympia and adjacent suburban communities
F-l
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Acquisition of Soil Data
EPA used soil coverage data provided as State Soil Geographic Database (STATSGO) mapping
units (Wolock 1997) to characterize soils present in each of the indicator cities. STATSGO
component and layer tables were accessed through Pennsylvania State University's active
archive (http://www.soilinfo.psu.edu/index.cgi?soil_data&index.html) for the representative
states per EPA Region. The authors of STATSGO describe it as follows:
This (STATSGO) data set is a digital general soil association map developed by the
National Cooperative Soil Survey and distributed by the Natural Resources Conservation
Service (formerly Soil Conservation Service) of the U.S. Department of Agriculture. It
consists of a broad based inventory of soils and nonsoil areas that occur in a repeatable
pattern on the landscape and that can be cartographically shown at the scale mapped. The
soil maps for STATSGO are compiled by generalizing more detailed soil survey maps.
Where more detailed soil survey maps are not available, data on geology, topography,
vegetation, and climate are assembled, together with Land Remote Sensing Satellite
(LANDSAT) images. Soils of like areas are studied, and the probable classification and
extent of the soils are determined.
The approximate minimum area delineated is 625 hectares (1,544 acres), which is
represented on a l:250,000-scale map by an area approximately 1 cm by 1 cm (0.4 inch
by 0.4 inch). Linear delineations are not less than 0.5 cm (0.2 inch) in width. The number
of delineations per 1:250,000 quadrangle typically is 100 to 200, but may range up to
400. Delineations depict the dominant soils making up the landscape. Other dissimilar
soils, too small to be delineated, are present within a delineation.
The data available in STATSGO are valuable because they provide enough detail to evaluate
broad trends in soil distribution but are still generalized sufficiently to permit analysis of many
acres. It is EPA's expectation that evaluating soil over large geographic areas will produce a
representative sample sufficient for analyzing sediment generation for the C&D industry.
As shown in Table F-2, EPA inventoried soils data from between 0.5 million and 5 million acres
in the area surrounding each indicator city. The intent was to identify soil types and soil
characteristics in each city's developing fringe. Nationally, 2,175 STATSGO statistical units
were individually evaluated, in combination providing soil data for 20 million acres. Typically,
the soils at each indicator city were represented by between 74 and 501 STASTSGO statistical
units.
Table F-2. Summary of STATSGO Evaluation of Indicator City Locations
Indicator city
Albany
Atlanta
Boise
Chicago
Dallas
Denver
Representing acreage
extracted from STATSGO
720,741
5,311,422
465,617
2,676,561
3,054,633
1,344,782
Number of statistical units
evaluated
239
130
93
501
161
151
F-2
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Indicator city
Kansas City
Las Vegas
Manchester
Seattle
Washington, DC
Total
Representing acreage
extracted from STATSGO
1,924,721
858,166
484,354
814,413
2,580,084
20,235,494
Number of statistical units
evaluated
268
100
101
74
357
2,175
The geographic limits of the STATSGO soil coverage evaluated were determined by
superimposing indicator city urban area boundaries (U.S. Census Bureau 2000) upon intersecting
RF1 watersheds (Nolan et al. 2003). The resulting list of RF1 watersheds intersecting the rapidly
developing indicator city urban areas was used to spatially identify underlying STATSGO soil
coverage Map Unit Identifiers (MUIDs). Last, the soil data associated with the surface soil layer
within the selected MUIDs were extracted from STATSGO to produce the suite of data
evaluated for each indicator city.
Table F-3 presents a summary of soil data for each indicator city, some of which were used to
develop hybrid soil distributions (detailed later) for each indicator city. The data shown are
spatially averaged, such that soil parameter values representing larger areas have a greater
influence than values representing smaller areas.
Table F-3. Summary of STATSGO Soil Data Extraction for Indicator Cities
Indicator city
Albany
Atlanta
Boise
Chicago
Dallas
Denver
Kansas City
Las Vegas
Manchester
Seattle
Washington, DC
Average
clay
percentage
17%
19%
17%
24%
38%
19%
27%
12%
6%
10%
16%
Average
silt
percentage
43%
26%
41%
57%
35%
25%
66%
16%
33%
31%
39%
Average
sand
percentage
40%
55%
43%
20%
27%
56%
7%
72%
61%
59%
45%
Average
RUSLE*
K factor
0.37
0.26
0.34
0.31
0.33
0.27
0.33
0.31
0.23
0.29
0.33
Average
percent
passing #200
sieve (sub-75
microns)
60%
45%
57%
80%
73%
44%
93%
28%
39%
41%
55%
Average
percent
passing #40
sieve (sub-
300 microns)
75%
77%
76%
92%
89%
63%
96%
47%
62%
58%
74%
* Revised Universal Soil Loss Equation
As noted in the description of STATSGO above, the coverage is a compilation of more detailed
soil survey data. As a result, STATSGO reports some soil parameters only in terms of a low and
a high value, or the range observed when more detailed data sources were compiled. For
F-3
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
example, for each of the 239 statistical units evaluated by for Albany, STATSGO provides 239
lowest-reported and highest-reported values for some soils parameters.
Where STATSGO provides a range of values, EPA used the average of the high and low in
subsequent computations (e.g., the values provided in Table F-3). As detailed below, EPA used
the STATSGO-reported range in slopes to estimate the possible range in soil yield from
construction sites.
Note the percent passing is also the percent of the total soil sample (by weight) that is smaller
than the opening of the sieve. As a result, it is possible to estimate the fraction of a soil sample
that is larger or smaller on the basis of the sieve used by the soil laboratory to process the
sample.
Applying the RUSLE to Estimate Construction Site Annual Yield
One of the more common methods for estimate the tons of soil eroded from soil surfaces is the
Revised Universal Soil Loss Equation (RUSLE) (USDA 2000). As shown in Equation 1, the
RUSLE is a regression equation that contains five parameters that account for site geometry and
conditions, the soil's tendency to erode, and the location of the site.
Equation F-l
Per Acre Yield of Eroded Soil Tons = R*K*LS*C*P
where
Land Condition Parameters
C = Cover Management Factor
P = Support Factor/Soil Management Factor
Soil Erosivity Factor
K = Soil Erosivity, tons/acre
Site Location Factor
R = Rainfall - Runoff Erosivity Factor
Site Geometry
LS = Length Slope Factor
Table F-4 provides an overview of the data sources used by EPA to obtain regional-specific
RUSLE factors customized to the nine construction model projects.
Selection of C and P Factors
EPA selected RUSLE C and P factors from information found in the SEDCAD 4 Design Manual
and User's Guide (Warner et al. 2006). The cover management factor C was set to 1, to represent
the absence of cover crop and tillage. EPA elected to assume the land area of each construction
model project would be cleared and grubbed in preparation for construction. The site would
F-4
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
remain denuded except for the footprint of structures. Hence, the support factor/soil management
factor was set to a value of 0.9, per guidance from SEDCAD 4.
Table F-4. Data Sources and Data Processing to Obtain RUSLE Factors
RUSLE
term
C
P
K
R
LS
Source of information
SEDCAD 4 Documentation*
SEDCAD 4 Documentation*
STATSGO***
RUSLE2 database**
Length factor estimated on the
basis of model project geometry
Regional slope ranges obtained
from STATSGO***
Processing for model project erosion estimation
Globally set to a value of 1 across all regions and model
projects. This is for a denuded soil surface
Globally set to a value of 0.9 across all regions and
model projects. This represents a Roughed and
Irregularly Tracked soil surface
Spatially averaged value determined from soils data for
each region's indicator city
Value provided for indicator city used either the R
reported for the city or reported for an adjacent county
Length and regional slope values combined to determine
LS value, on the basis of assumption of high ratio of rill -
to-interrill erosion.
* SEDCAD 4 Documentation (Warner et al. 2006)
** RUSLE 2 ARS Version Jan 19 2005, Program Database
*** STATSGO Soil Data Coverage
Selection of K Factors
The appropriate RUSLE K factor for each region was determined on the basis of STATSGO soil
coverage data. For each STATSGO statistical unit, a single K value is reported within coverage
data fields. EPA spatially averaged all of the individual Ks for each city to determine the region-
wide representative value. The K value for each indicator city was universally applied to all
states in the region. Attachment A lists how states are grouped into regions. Table F-5 indicates
the average K for each indicator city.
Table F-5. Spatially Averaged Regional Soil Erosivity (K) Values
City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Washington, DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average K*
0.369
0.264
0.229
0.340
0.315
0.331
0.332
0.268
0.331
0.314
0.293
*The STASTGO KKFACT data point
F-5
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
LS Factor Selection
The LS factor reflects the influence of the site geometry and land slope. As suggested by its
name, the LS factor combines the average slope for the eroding area with the flow distance
eroded particles will travel to the point of discharge. This term is referred to here as the overland
flow length; although in RUSLE terminology, it is commonly referred to as the slope length.
Usually, the LS factor is determined from U.S. Department of Agriculture (USDA) tables, where
users look up the appropriate value for the average percent slope and overland flow distance
(USDA 2000). EPA automated this lookup process by developing a curve that fits parameter
values found in the USDA tables. For the range of low-end and high-end slopes found in
STATSGO, this curve fit produces less than a 4 percent departure from table-reported LS values,
and typically only a 1 to 2 percent departure for most slopes evaluated for the regions.
USDA provides three sets of LS values based on the tendency for rills to formLS values for a
low, medium, and high ratio of rill-to-interrill erosion. EPA's analysis is based on a high ratio of
rill-to-interrill erosion (USDA 2000). USDA suggests that construction sites or other highly
disturbed soil surfaces are likely to have a high ratio of rill-to-interill erosion.
EPA elected to set slope lengths for model projects at ranges between 200 feet and 425 feet, to
reflect differences in geometries of various construction site project types. Typically, overland
flow distance on a construction site would be limited by slope and soil type, with the goal of
preventing sheet flow from becoming concentrated flow. As such, construction sites typically
will provide channels along slopes for collection and conveyance of runoff before the point
where overland sheet flow would become concentrated flow. Because the specific geometry
would vary for each individual project, EPA selected values that would provide a reasonable
approximation of slope lengths that might be found on a typical project. The overland flow or
RUSLE slope lengths selected for the nine model site projects are in Table F-6.
Table F-6. Model Project Slope Lengths (feet)
Model project description
Large Residential - median size 33 acres
Large Nonresidential - median size 5 1 acres
Large Transportation - median size 78.9 acres
Medium Residential - median size 16.7 acres
Medium Nonresidential - median size 15 acres
Medium Transportation - median size 16 acres
Small Residential - median size 3 acres
Small Nonresidential - median size 2.6 acres
Small Transportation - median size 3 acres
Overland flow distance
(feet)
350
425
200
350
425
200
150
250
200
F-6
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
A range of soil slopes were extracted for each region from the STATSGO soil coverage data. For
any single statistical unit, STATSGO provides a high and low slope value, where the high value
is the highest reported for the statistical unit, and the low value is the lowest reported. EPA
spatially averaged the lowest- and highest-reported slopes of the individual statistical units for
each city to determine the region-wide representative value. The regional lowest-reported and
highest-reported values were then used to determine the range of slopes construction sites would
likely encounter in a given geographic area.
Table F-7 indicates spatially averaged STATSGO lowest-reported and highest-reported slope
data, and presents slope values computed from the STATSGO data. EPA believes that using the
lowest-reported and highest-reported slopes would indicate the extremes, but not the more
common conditions faced by the industry. Therefore, EPA computed three slope values from the
STASTGO data for each indicatory city; values that reflect regional slope tendencies but offer a
more central estimate of the slopes likely to occur at construction sites.
For its analysis, EPA used the average of the lowest-reported and highest-reported slope values
for each indicator city to produce an average estimate of soil slope/erosion. A low-end estimate
of soil erosion was computed on the basis of the value halfway between the lowest-reported
slope value and the computed average slope value. A high-end soil erosion was computed on the
basis of the value halfway between the highest-reported slope value and the computed average
slope value.
For most the analysis of the industry, EPA used the computed average slope value for each
region to obtain a central estimate (loads based on the average slope are used in the SPARROW
model to compute changes in receiving water quality and to calculate benefits). The computed
low-end and high-end slope values provide an opportunity to see how changes in slope
assumptions could affect the results.
Table F-7. Slope Ranges from STATSGO and Computed Regional Slope Ranges for
Estimating Soil Erosion Yield
City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Washington, DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Origin STATSGO, percent
Average of
lowest reported
slopes
4.72%
7.55%
3.24%
7.71%
2.39%
1.17%
6.59%
3.38%
4.26%
5.60%
10.89%
Average of
highest
reported slopes
12.06%
15.18%
9.59%
18.71%
6.25%
5.62%
14.74%
17.83%
8.87%
16.98%
25.76%
Computed slopes, percent
Low end
6.55%
9.46%
4.83%
10.46%
3.35%
2.28%
8.63%
6.99%
5.41%
8.45%
14.60%
Average
8.39%
11.37%
6.42%
13.21%
4.32%
3.40%
10.67%
10.61%
6.57%
11.29%
18.32%
High end
10.22%
13.28%
8.00%
15.96%
5.28%
4.51%
12.71%
14.22%
7.72%
14.14%
22.04%
F-7
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Rainfall Erosivity Factor Selection
USDA Agricultural Research Service (ARS) makes available rainfall erosivity factors through
many outlets, including the recently published RUSLE 2 computer program (USDA 2005). EPA
used location-specific databases built into RUSLE 2 to acquire the appropriate R values for the
indicator cities (See Table F-8). Typically the value chosen for each indicator city was either the
R value reported for the city or reported for an adjacent county.
Table F-8. Regional Rainfall Erosivity (R) Factors
City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Washington, DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Rainfall R
105
318
107
6.75
158
273
176
30.6
226
12.5
77.8
Soil Delivery Ratios
When RUSLE is applied to agricultural situations, and/or where the slope length is long, it is
expected that some eroded soil particles will deposit as they move along the flow path. Such is
the case where water flow moves eroded particles along a crop row cut into a farm field's
topographic contour. The rough bottom and flat slope at the base of the row provide ample
opportunity for the recapture of eroded soil particles. The ratio of soil discharged to eroded
(moved) soil is referred to as the delivery ratio.
For construction sites, EPA elected to assume a delivery ratio of 1, or that 100 percent of the
eroded soil particles would be delivered to sediment controls. For construction sites, this is
justified in part by the industries tendency to install efficient flow systems (e.g., channels and
swales) that are designed to convey flow efficiently to the sediment control devices. This
convention helps ensure that the construction site work schedule is affected as little as possible
by precipitation.
EPA acknowledges that many types of construction site best management practices (BMPs),
(e.g., silt fences and check dams) do capture sand-size and larger soil particles when they are
properly placed and maintained within the flow path. However, these particles would also be
removed by baseline BMPs (such as sediment basins), and therefore EPA's baseline analysis
does account for removal of these particles. The technologies currently under consideration by
EPA (advanced treatment systems) are targeted at silt and clay particle size fractions, or the
F-8
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
fractions much less affected by flow path BMPs. Neglecting the role of flow path BMPs (i.e.,
assuming a delivery ratio of 1.0) therefore is not expected to significantly bias the results.
Estimating Soil Yield for Regional Models
Tables F-9a through F-9d provide EPA's estimates of erosion rates (low-end, average, and high-
end) for the 11 indicator cities. Note that the per acre erosion rates are the same for large
transportation, medium, and small transportation model projects. This occurs because the
overland length selected for these projects is the same (200 feet). Matching overland flow length
is also the reason why the per acre yield estimates match for small residential and small
nonresidential model projects. Each of the model projects predict a different amount of eroded
soil discharge at their outlet points, even if they have the same yield per acre. This occurs
because the median site size differs between the nine model construction projects.
Table F-9a. Estimated Soil Eroded from Large, Medium, and Small Transportation Model
Construction Projects (Tons per Acre)
Indicator city
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Denver
Kansas City
Las Vegas
Seattle
Washington, DC
Low-end estimate
47.05
159.12
21.18
5.09
28.80
34.77
10.70
73.38
6.32
82.42
96.50
Average estimate
62.03
211.69
29.04
7.20
37.97
53.15
18.59
90.99
9.78
112.12
133.58
High-end estimate
82.98
265.75
37.19
9.38
47.46
72.45
29.58
109.07
13.55
142.41
173.39
Table F-9b. Estimated Soil Eroded from Large and Medium Residential Model
Construction Projects (Tons per Acre)
Indicator city
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Denver
Kansas City
Las Vegas
Seattle
Washington, DC
Low-end estimate
65.72
229.69
7.41
37.88
44.19
15.04
100.76
9.04
28.79
123.69
138.15
Average estimate
89.58
310.64
10.71
51.10
70.00
27.11
127.13
14.34
40.48
171.70
194.91
High-end estimate
120.62
395.42
14.19
65.03
97.97
42.79
154.60
20.28
52.88
221.73
256.99
F-9
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Table F-9c. Estimated Soil Eroded from Large and Meduim Nonresidential Model
Construction Projects (Tons per Acre)
Indicator city
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Denver
Kansas City
Las Vegas
Seattle
Washington, DC
Low-end estimate
73.79
260.88
8.45
41.66
48.03
16.92
112.47
10.23
32.02
142.39
156.46
Average estimate
100.24
354.85
12.30
56.64
77.02
30.90
142.76
16.37
45.43
199.06
222.21
High-end estimate
137.33
453.87
16.39
72.54
108.64
49.21
174.49
23.32
59.75
258.54
294.57
Table F-9d. Estimated Soil Eroded from Small Nonresidential and Small Residential
Model Construction Projects (Tons per Acre)
Indicator city
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
Denver
Kansas City
Las Vegas
Seattle
Washington, DC
Low-end estimate
53.75
184.20
5.91
32.12
38.26
12.26
83.27
7.29
23.94
96.90
111.34
Average estimate
71.50
246.67
8.44
42.75
59.32
21.60
103.97
11.39
33.15
132.89
155.30
High-end estimate
96.33
311.38
11.07
53.81
81.68
33.57
125.57
15.92
42.79
169.91
202.85
Additional details on the application of RUSLE to the nine model construction projects, on the
basis of STATSGO data, are in Attachment B.
Uncertainty of Estimated Construction Site Soil Yield
EPA recognizes that soil yield will vary among actual construction projects, even those that are
very similar to the model projects evaluated in this document. EPA recognizes that it cannot
perform detailed analysis of all combinations of soil type, soil slope, slope profile, and overflow
flow length. However, EPA did evaluate some of the variability surrounding its estimate of per
acre annual erosion for construction sites. This analysis focused on variation in slope at indicator
cities, as indicated by the STATSGO soil data coverage. The results are presented in terms of
low-end and high-end and average soil yields, as presented in Tables F-9a through F-9d.
F-10
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
The low-end estimates of slope produce erosion rates that are between 19 and 45 percent lower
than those that result from average slope values, depending on the model and region. The high-
end estimates of slope predict erosion rates that are greater than average slope values by between
20 and 59 percent.
Application of STATSGO Data for Particle Grain Size Distribution
EPA's assessment of the effectiveness of technologies is based on particle size distributions for
soil eroded from construction sites. STATSGO data provide a basis for estimating particles size
distributions of soils. The data in Table F-3 represent the data that are spatially weighted and
region-specific. The data represent the grain size distribution of a hybrid soil, or a composite soil
created by proportionally weighting the soils data in the area surrounding each indicator city.
Each hybrid soil provides sufficient accuracy to estimate the contribution of each soil particle
size group to the total eroded yield from construction sites.
With the STATSGO-developed percent passing data for regional hybrid soils in Table F-3, it is
possible to estimate the percent passing for other particle sizes. For this analysis, EPA used the
Skaggs et al. Equation (see Equation F-2)(Skaggs et al. 2001), which was fit to the hybrid soil
data for the average percent clay, percent passing a #200 sieve, and passing a #40 sieve.
Once the Skaggs et al. Equation parameters are determined for each region's hybrid soil, the
region-specific equation can then be used to develop a particle size distribution for the hybrid
soils. These particle size distributions can be used to estimate the percent by weight above and
below any selected particle size. Exhibit F-l documents the application of the Skaggs et al.
Equation to each region's hybrid soil and the resulting regional estimates of percent passing for
select particle sizes.
Many of the technologies being considered by EPA for the C&D industry remove pollutants
proportionally to the size of the soil particles that flow into them. The finer the suspended soil
particle, the more difficult it is to remove the particle through settling technology (e.g.,
sedimentation basin). As shown in Exhibit F-l, the fraction of small particles found in surface
soils varies significantly region-to-region. For example, the fraction of soils smaller than 20
microns, ranges from a low of 21 percent (Las Vegas) to a high of 90 percent (Kansas City). This
highlights the difference between areas with sandy soils and those with clayey soils.
F-ll
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Skaggs et.al. Particle distribution curve equation
Fir) =
where rO, r1, r2 are the radii for three calibration particle sizes
p(0), p(1), p(2) are the percent passing for the three calibration particles
and
C = dill
II =
V = 111
I / / t I'll I I
1.'i (r\
1*2
Mi zz: 1 f 1
isi
p = cd
o. /% > /-, ::;> r,, :> u
Reference:
Estimating Particle-Size Distribution from Limited Soil Texture Data
T. H. Skaggs,* L. M. Arya, P. J. Shouse, and B. P. Mohanty
Equation F-2. Skaggs et al. Equation for Fitting Soil Particle Distributions
F-12
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Fitting Skaggs e
Region Indicator City
2 Albany
4 Atlanta
10a Boise
5 Chicago
6 Dallas
8 Denver
7 Kansas City
9 Las Vegas
1 Manchester
10b Seattle
3 DC
Estimated Percent Smaller by Weig
Region Indicator City
2 Albany
4 Atlanta
10a Boise
5 Chicago
6 Dallas
8 Denver
7 Kansas City
9 Las Vegas
1 Manchester
10b Seattle
3 DC
.al. Equation to Av
Percent Passing A
Pro
2 micron -
Percent clay
17.0
18.7
16.9
23.5
38.4
19.0
26.7
12.0
6.4
10.3
15.6
srage STATSGO soil data for indicator cities
Global Skaggs et.al. Parameters
Equ. Parameter Dia, micron Radius, micron
ro
r1
r2
2
75
300
verage Data from STATSGO
Pr1
75 micron Passing
#200 Sieve
60.5
44.7
57.5
80.1
73.4
44.2
93.1
27.7
39.4
40.8
54.7
ht for Select Particle Size
2 5
17.0 43.4
18.7
16.9
23.5
38.4
19.0
26.7
12.0
6.4
10.3
15.6
27.5
39.0
63.0
56.6
29.7
86.4
17.3
22.7
26.0
36.5
Pr2
300 microns Passing
#40 Sieve
75.2
77.2
76.2
92.0
88.6
63.2
96.5
46.7
62.0
57.8
73.7
10
47.3
30.4
42.9
67.2
60.3
32.5
88.4
19.1
25.9
29.0
40.3
1
37.5
150
Region Specific SkaggsEquation Parameter Calculation
v w alpha Beta u c
0.044
0.032
0.043
0.031
0.013
0.031
0.027
0.050
0.145
0.078
0.048
0.047
0.042
0.048
0.033
0.015
0.038
0.028
0.065
0.155
0.085
0.052
Particle Diameter, Microns
20 30
51.2 53.8
33.9
47.1
71.3
64.1
35.6
90.0
21.2
29.5
32.3
44.4
36.4
49.8
73.8
66.6
37.7
91.0
22.7
32.0
34.5
47.1
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
-0.711
50
57.3
40.5
53.8
77.2
70.1
41.0
92.2
25.1
35.7
37.7
51.0
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
-2.557
75
60.5
44.7
57.5
80.1
73.4
44.2
93.1
27.7
39.4
40.8
54.7
-0.036
-0.017
-0.034
-0.027
-0.008
-0.019
-0.026
-0.025
-0.124
-0.062
-0.037
150
66.9
55.7
65.4
85.6
80.0
51.6
94.8
34.2
48.1
47.7
62.6
0.051
0.184
0.068
0.037
0.122
0.142
0.010
0.188
0.045
0.064
0.068
300
75.2
77.2
76.2
92.0
88.6
63.2
96.5
46.7
62.0
57.8
73.7
400
79.3
93.7
82.0
95.1
93.0
70.2
97.2
56.1
70.7
63.6
79.8
Exhibit F-l. Application of Skaggs et al. Equation to Indicator City Soils
F-13
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Areas for Additional Investigation
EPA acknowledges that there is ongoing investigation of soil and soil erosion behavior that is not
incorporated into the analysis documented in this proposal. For example, data suggests that when
erosion of a soil surface occurs, the primary soil clay, silt, and sand particles flow down gradient
as individual particles and as conglomerates of small and large soil aggregate. Conglomeration of
soil particles exists because of chemical and physical adhesionadhesion that can range from
slightly to strongly water resistant depending on the soil.
In this document, EPA refers to the STATSGO-based soil distribution as the parent soil
distribution to distinguish it from the eroded distribution that probably contains a greater fraction
of small and large soil conglomerate particles. Attachment C provides details for twelve USDA
soil texture classes the parent soil particle size distribution and the associated eroded particle size
distribution.
Table F-10 provides summary information on small and large aggregate size in eroded soil on
the basis of the parent soil distributions of 12 USDA soil texture classes. Note: the fraction of
small and large particle aggregates and their estimated average diameter were obtained from
relationships found in USDA's RUSLE2 Science Documentation (USDA 2005). In summary, for
each of the 12 soil texture classes that span the soil spectrum, the estimated eroded soil
distribution contains a greater percentage of large diameter particles than its parent soil.
Table F-10 Summary of Small and Large Soil Aggregate Potentially Found in Eroded Soils
Particle
description
Small Aggregate
Large Aggregate
Particle sizes
Composed of clay
(< 2 microns) and
silts (2 to 50
microns) and sands
Composed of clay
(< 2 microns), silts
(2 to 50 microns)
and sands
Estimated aggregate size
(microns) and fraction within
eroded soil sample *
30 and 100 microns in size
Representing between 5 to 40 % of
eroded soil weight
300 and 1,600 microns in size
Representing between 7 to 80 % of
soil eroded soil weight
Description of
aggregate size
Very fine sand to fine
sand
Medium sand to coarse
sand
* Range computed from 12 USDA soil texture classes
EPA's analysis of new technologies and new design criteria for the C&D industry is based on
parent soil distributions, not eroded soil distributions. EPA expects that this approach will
underestimate removal efficiencies for technologies because of settling (e.g., sedimentation
ponds). EPA acknowledges that where the flow distance to the sediment basins is short, the
eroded particle distribution entering the basin will probably contain a greater percentage of larger
diameter particles than is suggested by dry sieve analysis of the parent soil.
The load allocation spreadsheet is DCN 43091, the estimate of construction site loads is DCN
43092 and the STATSGO soil data evaluation is DCN 43096 in the Administrative Record.
F-14
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
REFERENCES
Nolan, J.V., J.W. Brakebill, R.B. Alexander, and G.E. Schwarz. 2003. ERF1_2 - Enhanced
River Reach File 2.0. U.S. Geological Survey Open-File Report 02-40, U.S. Geological
Survey, Reston, VA. .
Skaggs T.H., L.M. Arya, PJ. Shouse, and B.P. Mohanty. 2001. Estimating particle-size
distribution from limited soil texture data. Soil Science Society of America Journal, 65(4):
1038-1044.
U.S. Census Bureau. 2000. Urbanized Areas Cartographic Boundary Files. U.S. Bureau of the
Census, Washinton, DC. .
USDA (U.S. Department of Agriculture). 2000. Predicting Soil Erosion by Water: A Guide to
Conservation Planning With the Revised Universal Soil Loss Equation (RUSLE). Agriculture
Handbook Number 703. U.S. Department of Agriculture, Agricultural Research Service.
Washington, DC.
USDA (U.S. Department of Agriculture). 2005. RUSLE 2 Documentation. U.S. Department of
Agriculture, Washington, DC.
. Accessed February
2008.
Warner, R., P. Schwab, and D. Marshall. 2006. SEDCAD 4.0 for Windows, Design Manual and
User's Guide 2006. Civil Software Design, LLC, Lexington, KY.
Wolock, D.M. 1997. STATSGO Soil Characteristics for the Conterminous United States: U.S.
Geological Survey Open-File Report 97-656. U.S. Geological Survey, Reston VA.
.
F-15
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Attachment A. Allocation of States/Commonwealths/Territories to Representative Regions
State
Alabama
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
Abbreviation
AL
AZ
AR
CA
CO
CT
DE
FL
GA
ID
IL
IN
IA
KS
KY
LA
ME
MD
MA
MI
MN
MS
MO
MT
NE
NV
NH
EPA Region
4
9
6
9
8
1
3
4
4
lOa
5
5
7
7
4
6
1
3
1
5
5
4
7
8
7
9
1
State
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Alaska
Hawaii
Puerto Rico
Virgin Islands
Pacific Islands
District of
Columbia
Abbreviation
NJ
NM
NY
NC
ND
OH
OK
OR
PA
RI
SC
SD
TN
TX
UT
VT
VA
WA
WV
WI
WY
AK
HI
PR
VI
PI
DC
EPA Region
2
6
2
4
8
5
6
lOb
3
1
4
8
4
6
8
1
3
lOb
3
5
8
Not analyzed
Not analyzed
Not analyzed
Not analyzed
Not analyzed
3
F-16
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Attachment B. Regional Estimates of Construction Site Annual Yield for Model Projects
General Note: Medium Model Projects have the same RUSLE parameters as Large Model
Projects
RUSLE Input Parameters
Model Project: Medium and Large Commercial
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
2.12
3.45
1.45
4.09
0.93
0.59
2.98
2.29
1.67
2.90
6.95
Average
2.87
4.69
2.06
5.95
1.27
0.95
4.23
4.19
2.12
4.64
9.71
High End
3.94
6.00
2.71
7.93
1.62
1.33
5.60
6.67
2.59
6.61
12.61
*EPA Applied LS values for High Rill to Intertill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE"C"
Comments
425 Feet Value taken from model project geometry
0.9 Umtless Value taken from SEDCAD 4 Documentation
1 Unitless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
73.79
260.88
32.02
8.45
41.66
48.03
156.46
16.92
112.47
10.23
142.39
Average
100.24
354.85
45.43
12.30
56.64
77.02
222.21
30.90
142.76
16.37
199.06
High End
137.33
453.87
59.75
16.39
72.54
108.64
294.57
49.21
174.49
23.32
258.54
Departure from Aver
Low End [High End
26%
26%
30%
31%
26%
38%
30%
45%
21%
38%
-37%
-28%
-32%
-33%
-28%
-41%
-33%
-59%
-22%
-42%
F-17
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
RUSLE Input Parameters
Model Project: Small Commercial
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
1.54
2.44
1.09
2.86
0.72
0.47
2.12
1.66
1.24
2.07
4.73
Average
2.05
3.26
1.50
4.09
0.96
0.73
2.95
2.93
1.54
3.23
6.48
High End
2.76
4.12
1.94
5.36
1.20
1.00
3.86
4.55
1.86
4.51
8.29
*EPA Applied LS values for High Rill to Merrill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE "C"
Comments
250 Feet Value taken from model project geometry
0.9 Unitless Value taken from SEDCAD 4 Documentation
1 Unitless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
53.75
184.20
23.94
5.91
32.12
38.26
111.34
12.26
83.27
7.29
96.90
Average
71.50
246.67
33.15
8.44
42.75
59.32
155.30
21.60
103.97
11.39
132.89
High End
96.33
311.38
42.79
11.07
53.81
81.68
202.85
33.57
125.35
15.92
169.91
Departure from Aver
Low End [High End
25%
25%
25%
36%
43%
20%
-35%
-26%
-29%
-31%
-26%
-38%
-31%
-55%
-21%
F-18
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
RUSLE Input Parameters
Model Project: Medium and Large Residential
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
1 .88
3.04
1.31
3.59
0.85
0.54
2.63
2.04
1.50
2.56
6.03
Average
2.54
4.11
1.84
5.19
1.14
0.86
3.71
3.67
1.89
4.06
8.38
High End
3.46
5.23
2.40
6.87
1.45
1.20
4.89
5.80
2.30
5.75
10.82
*EPA Applied LS values for High Rill to Intertill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE"C"
Comments
350 Feet Value taken from model project geometry
0.9 Umtless Value taken from SEDCAD 4 Documentation
1 Unitless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
65.72
229.69
28.79
7.41
37.88
44.19
138.15
15.04
100.76
9.04
123.69
Average
88.58
310.64
40.48
10.71
51.10
70.00
194.91
27.11
127.13
14.34
171.70
High End
120.62
395.42
52.88
14.19
65.03
97.87
256.99
42.79
154.60
20.28
221.73
Departure from Aver
Low End [High End
31%
26%
37%
29%
45%
21%
37%
-27%
-31%
-32%
-27%
-40%
-32%
-58%
-22%
-41%
F-19
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
RUSLE Input Parameters
Model Project: Small Residential
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
1.54
2.44
1.09
2.86
0.72
0.47
2.12
1.66
1.24
2.07
4.73
Average
2.05
3.26
1.50
4.09
0.96
0.73
2.95
2.93
1.54
3.23
6.48
High End
2.76
4.12
1.94
5.36
1.20
1.00
3.86
4.55
1.86
4.51
8.29
*EPA Applied LS values for High Rill to Merrill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE "C"
Comments
250 Feet Value taken from model project geometry
0.9 Unitless Value taken from SEDCAD 4 Documentation
1 Unitless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
53.75
184.20
23.94
5.91
32.12
38.26
111.34
12.26
83.27
7.29
96.90
Average
71.50
246.67
33.15
8.44
42.75
59.32
155.30
21.60
103.97
11.39
132.89
High End
96.33
311.38
42.79
11.07
53.81
81.68
202.85
33.57
125.35
15.92
169.91
Departure from Aver
Low End [High End
25%
25%
25%
36%
43%
20%
-35%
-26%
-29%
-31%
-26%
-38%
-31%
-55%
-21%
F-20
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
RUSLE Input Parameters
Model Project: Medium and Large Transportation
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
1.35
2.10
0.96
2.46
0.64
0.43
1.84
1.45
1.09
1.79
4.02
Average
1.78
2.80
1.32
3.49
0.85
0.65
2.54
2.52
1.35
2.77
5.47
High End
2.38
3.51
1.69
4.54
1.06
0.89
3.30
3.87
1.62
3.84
6.95
*EPA Applied LS values for High Rill to Interrill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE "C"
Comments
200 Feet Value taken from model project geometry
0.9 Umtless Value taken from SEDCAD 4 Documentation
1 Umtless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
47.05
159.12
21.18
5.09
28.80
34.77
96.50
10.70
73.38
6.32
82.42
Average
62.03
211.69
29.04
7.20
37.97
53.15
133.58
18.59
90.99
9.78
112.12
High End
82.98
265.75
37.19
9.38
47.46
72.45
173.39
28.58
109.07
13.55
142.41
Departure from Aver
[Low End High End
24%
25%
27%
29%
24%
35%
28%
42%
-34%
-30%
-54%
-20%
-39%
-27%
F-21
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
RUSLE Input Parameters
Model Project: Small Transportation
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Region
2
4
1
lOa
5
6
3
8
7
9
lOb
Average k
0.37
0.26
0.23
0.34
0.31
0.33
0.33
0.27
0.33
0.31
0.29
Annual R
105.0
318.0
107.0
6.8
158.0
273.0
176.0
30.6
226.0
12.5
77.8
LS Values *
Low End
1.35
2.10
0.96
2.46
0.64
0.43
1.84
1.45
1.09
1.79
4.02
Average
1.78
2.80
1.32
3.49
0.85
0.65
2.54
2.52
1.35
2.77
5.47
High End
2.38
3.51
1.69
4.54
1.06
0.89
3.30
3.87
1.62
3.84
6.95
*EPA Applied LS values for High Rill to Merrill Development
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
STATSGO Slope Data, Percent
Lowest
4.72
7.55
3.24
7.71
2.39
1.17
6.59
3.38
4.26
5.60
10.89
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
Highest
12.1
15.2
9.6
18.7
6.2
5.6
14.7
17.8
8.9
17.0
25.8
EPA Applied Slopes, Percent
Low End
6.55
9.46
4.83
10.46
3.35
2.28
8.63
6.99
5.41
8.45
14.60
Average
8.39
11.37
6.42
13.21
4.32
3.40
10.67
10.61
6.57
11.29
18.32
High End
10.22
13.28
8.00
15.96
5.28
4.51
12.71
14.22
7.72
14.14
22.04
Overland Flow Length
RUSLE "P"
RUSLE "C"
Comments
200 Feet Value taken from model project geometry
0.9 Unitless Value taken from SEDCAD 4 Documentation
1 Unitless Value taken from SEDCAD 4 Documentation
Calculated ranges in soil yield, Tons per acre per year
Indicator City
Albany
Atlanta
Manchester
Boise
Chicago
Dallas
DC
Denver
Kansas City
Las Vegas
Seattle
Low End
47.05
159.12
21.18
5.09
28.80
34.77
96.50
10.70
73.38
6.32
82.42
Average
62.03
211.69
29.04
7.20
37.97
53.15
133.58
18.59
90.99
9.78
112.12
High End
82.98
265.75
37.19
9.38
47.46
72.45
173.39
28.58
109.07
13.55
142.41
Departure from Aver
Low End [High End
24%
25%
27%
29%
24%
35%
28%
42%
19%
35%
-34%
-26%
-25%
-36%
-54%
-20%
F-22
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Attachment C. Comparison of Soil Particle Distributions of Common Soil Texture Groups
Table 3A-1. Computed Soil Distribution (Percent by Weight) for 12 Common Soil Texture Classes
PARENT SOIL DISTRIBUTION PER TEXTURE CLASS
Value Taken from Mid-point of Soil Triangle
Primary Primary Primary
USDA and NRCS 12 Textures Percent Clay Percent Silt Percent Sand
ERODED DISTRIBUTION VALUES
Sand
Loamy sand
Silt
Sandy loam
Silt loam
Loam
Sandy clay loam
Silty clay loam
Clay loam
Sandy clay
Silty clay
Clay
5
7
7
10
15
20
27
33
35
40
45
80
5
7
87
25
65
40
15
57
33
5
50
10
90
86
6
65
20
40
58
10
32
55
5
10
Percent in Eroded Material **
Clay Silt
1.3%
1.8%
1.8%
2.6%
3.9%
5.2%
7.0%
8.6%
9.1%
10.4%
1 1 .7%
20.8%
0.01%
0.01%
74.4%
7.0%
38.0%
4.0%
0.01%
16.8%
0.01%
0.01%
17.0%
0.01%
Small Large
Sand Aggregate Aggregate
69.6%
59.8%
4.2%
38.4%
8.9%
13.1%
12.0%
1.4%
3.7%
4.3%
0.3%
0.0%
5.0%
7.0%
12.6%
18.0%
27.0%
36.0%
15.0%
40.2%
33.0%
5.0%
33.0%
10.0%
24.1%
31 .4%
7.0%
34.0%
22.2%
41 .7%
66.0%
33.1%
54.2%
80.3%
38.0%
69.2%
** Draft Science Documentation RUSLE2, January 1st, 2005
Terms: Psl = Percent silt, Pc= Percent clay, Fsa = eroded percent small aggregate, Fla = eroded percent large aggregate
F-23
-------
Appendix F: Evaluating Soil Nature and Soil Erosion Representative of Major U.S. Metropolitan Areas
Table 3A-2. Computed
Eroded Particle Diameters for Five Particle
Classes
Sizes (Percent by Weight) for 12
PARENT SOIL DISTRIBUTION PER TEXTURE CLASS
Physical Parameters
USDA and NRCS 12 Textures
Sand
Loamy sand
Silt
Sandy loam
Silt loam
Loam
Sandy clay loam
Silty clay loam
Clay loam
Sandy clay
Silty clay
Clay
Diameter (mm)
Primary Primary
Percent Clay Percent Silt
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
0.002 0.01
**
Primary
Percent Sand
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
Specific Gravity *
Primary
Percent Clay
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
0.002
2.6
Common Soil
Texture
ERODED DISTRIBUTION VALUES
Diameter (mm)
Primary
Percent Silt
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
2.65
**
Primary
Percent Sand
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
2.65
Small Large
Aggregate Aggregate
0.03
0.03
0.03
0.03
0.03
0.03
0.034
0.046
0.05
0.06
0.07
0.1
1.8
0.3
0.3
0.3
0.3
0.3
0.4
0.54
0.66
0.7
0.8
0.9
1.6
1.6
** Draft Science Documentation RUSLE2, January 1st, 2005
Terms: Pel = percent clay
F-24
-------
Appendix G
Turbidity Report Tables
-------
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
10/28/2004
10/29/2004
10/29/2004
10/29/2004
10/29/2004
10/29/2004
11/01/2004
11/01/2004
11/01/2004
11/01/2004
11/01/2004
11/01/2004
1 1/02/2004
1 1/02/2004
1 1/02/2004
1 1/02/2004
1 1/02/2004
1 1/02/2004
1 1/02/2004
1 1/03/2004
1 1/03/2004
1 1/03/2004
1 1/03/2004
1 1/03/2004
1 1/04/2004
1 1/04/2004
1 1/04/2004
1 1/04/2004
1 1/04/2004
1 1/05/2004
1 1/05/2004
1 1/05/2004
1 1/05/2004
1 1/05/2004
1 1/08/2004
1 1/08/2004
1 1/08/2004
1 1/08/2004
1 1/08/2004
1 1/08/2004
1 1/09/2004
1 1/09/2004
1 1/09/2004
1 1/09/2004
1 1/09/2004
1 1/09/2004
11/10/2004
Influent (NTU)
4400
4036
4204
3892
3612
3700
3900
4280
4800
Effluent (NTU)
1.09
2.6
5.3
3.1
7.8
9.4
1.79
0.97
0.95
1.25
2.1
1.11
1.92
1.02
1.12
0.96
1.58
1.38
0.96
1.1
1.12
1.33
9.6
8.6
3.62
10.8
8.6
12.6
11.1
20.1
12.1
19.2
16.4
12.9
26.4
21.6
3.38
11.6
3.38
10.5
1936
9.2
14.2
15.1
16.2
8.8
G-l
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
11/10/2004
11/10/2004
11/10/2004
11/10/2004
11/10/2004
11/10/2004
11/10/2004
11/10/2004
11/11/2004
11/11/2004
11/11/2004
11/11/2004
11/12/2004
11/12/2004
11/17/2004
11/17/2004
11/17/2004
11/17/2004
11/17/2004
11/17/2004
11/17/2004
11/17/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/18/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
11/19/2004
1 1/22/2004
Influent (NTU)
1936
4816
1590
Effluent (NTU)
13.1
13.7
16.8
16.4
7.47
11.7
4.68
13.8
4.95
12.9
10.9
11.2
0.48
0.5
1.08
7.09
7.77
7.93
8
7.33
7.12
6.63
4.67
6.43
8.02
7.29
7.34
6.94
6.85
6.33
6.87
6.29
6.54
5.98
5.24
5.54
6.7
5.67
5.35
5.65
4.54
4.56
4.85
4.3
4.95
4.91
5.42
G-2
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/22/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/23/2004
1 1/24/2004
1 1/24/2004
1 1/24/2004
1 1/24/2004
1 1/24/2004
1 1/24/2004
1 1/24/2004
12/02/2004
12/02/2004
12/02/2004
12/02/2004
12/02/2004
12/02/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/06/2004
12/07/2004
12/07/2004
12/07/2004
12/07/2004
12/07/2004
Influent (NTU)
853
Effluent (NTU)
5.2
5.04
4.71
5.06
4.77
4.34
5.12
4.29
4.66
4.01
4.3
3.84
4.41
3.73
4.1
4.22
4.32
4.61
4.47
5.24
5.36
4.13
5.03
5.09
4.17
4.33
4.4
2.84
1.55
1.46
0.82
0.44
0.42
3.88
4.76
5.09
0.92
0.45
0.45
0.64
0.67
0.37
0.61
0.31
0.45
0.31
0.47
G-3
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
12/07/2004
12/07/2004
12/07/2004
12/07/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/08/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/09/2004
12/10/2004
12/10/2004
12/10/2004
12/10/2004
12/10/2004
12/10/2004
12/10/2004
12/10/2004
12/13/2004
12/13/2004
12/13/2004
12/13/2004
12/13/2004
12/13/2004
12/13/2004
12/14/2004
12/14/2004
12/14/2004
Influent (NTU)
Effluent (NTU)
0.54
0.33
0.31
0.41
0.99
0.26
0.23
0.55
0.2
0.33
0.33
0.28
0.28
0.3
0.97
0.2
0.29
0.94
0.8
0.86
0.29
0.6
4.6
0.35
0.32
0.38
0.91
0.45
0.3
0.69
1.55
0.25
0.3
0.23
0.8
0.25
0.34
0.36
0.48
0.42
0.37
0.24
0.3
0.32
0.77
0.3
0.51
G-4
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
12/14/2004
12/14/2004
12/14/2004
12/14/2004
12/14/2004
12/15/2004
12/15/2004
12/15/2004
12/15/2004
12/15/2004
12/15/2004
12/15/2004
12/15/2004
12/16/2004
12/16/2004
12/16/2004
12/16/2004
12/16/2004
12/16/2004
12/16/2004
12/16/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/17/2004
12/20/2004
12/20/2004
12/20/2004
12/20/2004
12/20/2004
12/20/2004
12/20/2004
12/20/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
12/21/2004
Influent (NTU)
2794
2072
1466
2140
2108
Effluent (NTU)
0.53
0.38
0.27
0.34
0.66
0.91
0.6
0.45
1.2
1.4
1.61
1.6
7.92
0.48
1.55
0.66
0.37
0.43
0.44
0.55
2.13
0.6
1.26
0.58
0.43
0.4
0.57
0.47
0.49
0.57
0.47
0.67
0.6
0.43
0.41
0.38
0.42
0.53
0.53
0.23
1.54
0.23
0.33
0.39
0.45
0.56
5.13
G-5
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
12/21-22/2004
12/21-22/2004
12/21-22/2004
12/21-22/2004
12/21-22/2004
12/21-22/2004
12/22/2004
12/22/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/28/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
Influent (NTU)
1772
1358
1000
Effluent (NTU)
2.74
3.02
3.27
2.28
2.17
2.3
0.59
7.45
12.3
14.5
14.3
15.4
2.01
0.94
0.92
0.76
1.41
1.3
0.69
0.71
0.59
1
20.4
19.5
20
19.6
2.19
0.7
0.74
0.99
0.47
1.13
0.75
1.06
1.76
1.99
1.78
1.06
0.5
0.8
1.25
0.73
1.01
1.97
2.65
0.61
0.99
G-6
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02-03/2005
01/02-03/2005
01/02-03/2005
01/02-03/2005
01/02-03/2005
01/02-03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
Influent (NTU)
Effluent (NTU)
1.33
1.53
1.07
0.95
1.18
0.73
1.42
1.11
0.71
1.04
1.03
0.97
1.01
0.87
1.47
1.13
1.53
1.08
1.55
3.73
1.87
0.97
1.21
3.77
2.5
2.36
1.98
1.49
1.85
1.54
1.43
1.25
1.25
1.82
2.71
1.95
2.59
1.67
3.48
2.62
1.75
2
2.11
2.86
3.23
1.98
2.03
G-7
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/03-04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04-05/2005
01/04-05/2005
01/04-05/2005
01/04-05/2005
01/04-05/2005
01/04-05/2005
01/04-05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
Influent (NTU)
Effluent (NTU)
2.47
2.86
2.21
1.96
1.76
1.58
1.24
2.29
1.46
1.45
1.85
1.35
4.55
2.69
1.75
2.27
1.91
1.25
3.55
1.5
2.68
2.11
1.23
1.28
4.33
25.8
3.01
2.39
2.62
2.02
1.87
1.79
1.55
2.59
3.89
7.88
7.95
4.65
2.69
1.84
1.68
2.57
1.61
1.7
1.2
1.46
1.73
G-8
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06-07/2005
01/06-07/2005
01/06-07/2005
01/06-07/2005
01/06-07/2005
01/06-07/2005
01/06-07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07-08/2005
01/07-08/2005
01/07-08/2005
01/08/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/08-09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
Influent (NTU)
Effluent (NTU)
1.31
0.71
1.03
1.11
1.98
1.75
2.01
1.44
0.89
1.24
.88/6.5
2.53
1.73
1.56
2.31
3.89
5.25
5.46
8.92
1.76/6
4.77
3.54
3.14
2.75
3.78
3.88
4.46
4.82
4.7
3.75
4.37
5.25
4.54
4.34
4.79
4.9
4.29
4.63
3.76
3.78
3.3
3.35
3.85
3.14
3.14
3.01
2.73
G-9
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/09-10/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/10-11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/11-12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
Influent (NTU)
Effluent (NTU)
2.71
2.74
2.14
3.85
2.37
8.95
9.36
3.28
8.24
2.73
4.28
5.38
2.23
4.23
6.52
6.92
7.52
5.41
3.54
3.06
1.3
2.25
1.27
1.39
1.4
1.19
0.87
1.95
2.32
2.03
1.72
1.91
2.78
2.76
3.06
2.88
2.83
2.94
4.19
4.26
4.52
4.33
3.88
4.18
2.81
2.32
2.37
G-10
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/12/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/12-13/2005
01/13/2005
01/13/2005
01/13/2005
01/13-14/2005
01/13-14/2005
01/13-14/2005
01/13-14/2005
01/13-14/2005
01/13-14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/15/2005
01/15/2005
01/15/2005
01/15/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/15-16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
Influent (NTU)
Effluent (NTU)
2.62
2.45
3.06
2.97
3.18
2.86
2.51
3.27
2.12
2.73
3.15
2.72
2.28
4.91
4.77
4.1
4.8
13.8
2.61
8.06
4.46
10.48
11.9
4.81
2.46
1.9
6.15
9.26
17.8
4.16
7.29
11.3
12.1
2.64
5.57
1.54
6.05
4.55
5.05
5.76
5.6
4.8
3.11
2
2.31
1.52
1.56
G-ll
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16-17/2005
01/16-17/2005
01/16-17/2005
01/16-17/2005
01/16-17/2005
01/16-17/2005
01/16-17/2005
01/17/2005
01/17/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18-19/2005
01/18-19/2005
01/18-19/2005
01/18-19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
Influent (NTU)
Effluent (NTU)
1.08
1.03
0.86
1.11
0.57
0.91
1.99
0.76
0.97
0.85
0.52
0.63
0.87
1.14
1.45
1.13
2.33
3.21
3.74
2.55
2.27
1.7
3.68
2.15
2.4
1.98
5.7
6.78
2.47
3.54
2.17
2.71
5.46
4.49
3.92
3.28
3.78
4.89
6.65
5.14
6.49
7.22
4.52
4.28
3.29
2.63
2.7
G-12
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/19-20/2005
01/20/2005
01/20/2005
01/20/2005
01/20/2005
01/20/2005
01/20/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/20-21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
Influent (NTU)
1253
Effluent (NTU)
3.33
1.85
2.1
1.69
2.48
3.41
4.03
2.23
2.28
1.71
1.65
1.68
2.36
5.8
2.17
2.72
2.89
6.18
7.6
5.02
4.7
3.49
2.83
1.84
1.79
1.71
1.11
1.28
1.62
1.19
1.92
1.48
2.81
4.7
3.67
3.79
4.17
2.93
3.17
2.46
1.96
1.65
1.73
1.83
3.06
1.94
1.21
G-13
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/22/2005
01/22/2005
01/22/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23/2005
01/23-24/2005
01/23-24/2005
01/23-24/2005
01/23-24/2005
01/23-24/2005
01/23-24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24-25/2005
01/24-25/2005
01/24-25/2005
01/24-25/2005
01/24-25/2005
01/24-25/2005
01/24-25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/25-26/2005
01/25-26/2005
01/25-26/2005
Influent (NTU)
Effluent (NTU)
1.13
1.38
1.3
1.02
1.24
1.25
1.43
0.83
1.04
1.59
1.14
0.94
0.87
0.99
0.77
0.93
0.85
0.78
1.05
1.35
1.86
1.47
1.07
1.12
0.84
2.05
1.86
1.18
1.21
1.34
1.23
2.1
1.98
1.81
2.24
1.58
1.63
2.21
4.54
4.35
4.2
4.76
3.63
3.38
3.02
2.08
2.26
G-14
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/25-26/2005
01/25-26/2005
01/25-26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/26/2005
01/27/2005
01/27/2005
01/27/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/28/2005
01/29/2005
01/29/2005
01/29/2005
01/29/2005
01/29/2005
01/29-30/2005
01/29-30/2005
01/29-30/2005
01/29-30/2005
01/29-30/2005
01/29-30/2005
01/29-30/2005
01/30/2005
01/30/2005
01/30/2005
01/30/2005
01/30/2005
01/30/2005
01/30-31/2005
01/30-31/2005
01/30-31/2005
01/30-31/2005
Influent (NTU)
Effluent (NTU)
2.59
1.39
2.3
1.38
1.89
2.03
2.33
1.55
1.55
3.25
4.55
2.56
3.49
3.66
3.5
1.91
1.96
1.81
2.37
1.65
3.2
2.73
2.43
3.05
3.33
3.72
3.66
2.86
3.66
0.4
355
1.91
2.63
2.28
2.47
3.54
2.22
2.07
4.17
5.06
1.86
5.06
2.12
2.36
2.77
2.72
3.15
G-15
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/30-31/2005
01/30-31/2005
01/30-31/2005
01/30-31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/03-04/2005
02/07/2005
02/07/2005
02/07/2005
02/07/2005
02/07/2005
02/07/2005
02/08/2005
02/08/2005
02/08/2005
02/08/2005
02/08/2005
02/08/2005
02/09/2005
Influent (NTU)
1800
Effluent (NTU)
3.41
3.87
9.09
2.65
0.78
0.56
0.51
0.69
0.63
0.61
0.75
3.4
2.48
1.62
1.16
1.55
1.96
2.04
2.95
4.11
1.14
1.23
1.76
1.02
1.48
0.92
1.18
1.42
1.37
1.48
1.74
0.75
8.1
4.4
2.66
1.22
1.93
5.4
2.21
2.28
1.89
1.42
2.44
2.04
1.35
2.08
1.53
G-16
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
02/09/2005
02/09/2005
02/09/2005
02/09/2005
02/09/2005
02/09/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/14/2005
02/14/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/18/2005
02/18/2005
02/18/2005
02/19/2005
02/19/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/23/2005
02/23/2005
02/23/2005
02/24/2005
02/24/2005
02/24/2005
02/25/2005
02/25/2005
02/25/2005
02/25/2005
Influent (NTU)
Effluent (NTU)
1.49
1.59
1.51
1.32
1.24
1.9
1.27
1.22
1.53
1.87
1.53
1.86
1.29
2.17
1.66
1.55
1.25
1.01
0.69
1.13
1.42
1.79
1.26
1.37
0.9
0.93
1.21
0.74
0.74
0.73
0.51
1.05
0.47
0.62
0.82
0.84
0.96
0.64
0.48
1.31
1.25
3.38
1.09
1.8
1.98
2.97
1
G-17
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
02/25/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/27/2005
02/27/2005
02/27/2005
02/27/2005
02/27/2005
02/27/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/06/2005
03/06/2005
03/06/2005
Influent (NTU)
Effluent (NTU)
1.38
0.5
0.4
0.57
0.68
0.33
0.52
0.51
0.33
0.39
0.4
1.95
1.01
0.78
0.56
0.35
0.51
0.5
0.48
0.78
0.39
0.33
0.48
0.44
0.44
0.4
0.41
0.45
2.89
1.39
1.15
0.8
0.74
1.77
1.6
1.64
1.78
1.64
1.26
1.65
1.75
2.56
2.54
2.32
3.24
5.77
5.01
G-18
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
03/06/2005
03/06/2005
03/06/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/09/2005
03/09/2005
03/09/2005
03/09/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/10/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/11/2005
03/14/2005
03/14/2005
03/14/2005
03/14/2005
03/14/2005
03/14/2005
Influent (NTU)
Effluent (NTU)
5.21
4.82
2.53
1.46
1.36
0.73
0.52
1.47
1.48
1.07
1.13
0.87
0.58
0.67
1.04
0.51
0.45
0.59
0.77
1.7
0.69
0.66
0.57
0.45
0.88
0.49
0.78
0.38
0.4
0.49
0.59
0.56
0.46
0.56
0.43
0.35
0.48
0.41
0.62
0.49
0.46
0.35
0.39
0.59
0.5
0.43
0.62
G-19
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
03/14/2005
03/14/2005
03/14/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/15/2005
03/16/2005
03/16/2005
03/16/2005
03/16/2005
03/16/2005
03/16/2005
03/16/2005
03/16/2005
03/17/2005
03/17/2005
03/17/2005
03/17/2005
03/17/2005
03/17/2005
03/17/2005
03/17/2005
03/18/2005
03/18/2005
03/18/2005
03/21/2005
03/21/2005
03/21/2005
03/21/2005
03/21/2005
03/21/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
03/22/2005
Influent (NTU)
Effluent (NTU)
0.33
0.42
0.4
0.78
0.63
0.5
0.51
0.69
0.64
0.58
0.53
0.32
0.61
0.63
0.59
0.55
0.8
0.66
0.75
0.71
0.89
0.89
0.78
0.58
0.55
0.42
0.72
0.52
1.21
0.26
0.4
0.82
0.56
0.44
0.33
0.34
0.29
0.63
0.22
0.51
0.24
0.38
0.29
0.26
0.31
0.42
0.35
G-20
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
03/22/2005
03/22/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
Influent (NTU)
Effluent (NTU)
0.33
0.31
5
5
5
5
5
5
5
4
2
0.59
0.51
0.35
0.55
0.59
0.49
0.51
0.47
0.41
0.72
0.62
0.7
0.65
0.86
0.78
0.88
0.75
1.07
0.34
0.37
0.47
0.39
0.44
0.48
0.58
0.39
0.33
0.34
0.3
0.35
0.73
0.71
0.75
0.67
0.71
0.58
G-21
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
03/26/2005
03/26/2005
03/26/2005
03/26/2005
03/26/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/29/2005
03/30/2005
03/30/2005
03/30/2005
03/30/2005
03/30/2005
03/30/2005
Influent (NTU)
1520
Effluent (NTU)
0.94
0.98
0.96
0.91
0.87
1.14
1.16
1.69
1.68
1.66
1.7
1.67
1.69
1.61
2.3
2.36
2.34
2.28
2.2
2.05
2.72
2.1
2.2
2.2
2.4
4.13
0.79
0.51
0.64
0.91
0.9
0.85
0.83
1.55
1.34
1.36
0.96
0.98
1.02
0.79
0.81
1.12
0.54
0.75
0.63
0.81
0.87
G-22
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
3
Date
03/30/2005
03/30/2005
03/30/2005
03/30/2005
03/30/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/30-31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
03/31/2005
04/01/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/22-23/2005
12/31/2004
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
Influent (NTU)
289
381
380
380
380
380
99.9
99.9
99.9
99.9
99.9
Effluent (NTU)
0.92
1.05
1.4
1.28
1.04
1.74
1.73
1.35
1.24
1.34
1.3
1.41
1.4
2.21
2.39
2.19
1.86
1.86
1.75
1.69
1.4
1.56
1.57
1.66
1.14
1.16
1.34
87
1.52
1.04
1
0.85
1.11
1.02
1.05
1.41
1
1
0
0
0
0
0.8
2
1.6
1.2
1.4
G-23
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Date
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/04/2005
01/04/2005
01/04/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/25/2005
01/25/2005
02/07/2005
02/07/2005
02/07/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/10/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
02/11/2005
Influent (NTU)
99.9
99.9
99.9
99.9
99.9
99.9
87.2
180.1
49.9
99.9
99.9
99.9
99.9
99.9
99.9
99.9
Effluent (NTU)
1.8
0.9
1.2
0.04
1.6
0.6
1.1
0.6
0.8
0.4
0.6
0.7
0.4
0.4
0.6
0.2
3.7
5.5
1.9
0.5
0.5
0.6
1.2
2.4
0.3
0.4
1.3
2.2
1.3
2.9
2.5
26
1.2
1.7
2
3.7
6.6
12.2
3
3.6
3.5
4.3
6.4
6.3
15
G-24
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Date
02/11/2005
02/14/2005
02/14/2005
02/14/2005
02/14/2005
02/14/2005
02/14/2005
02/14/2005
02/23/2005
02/23/2005
02/23/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
03/01/2005
03/01/2005
03/01/2005
03/01/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/07/2005
03/07/2005
03/24/2005
03/24/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
Influent (NTU)
46.3
35.8
48.2
6.6
86.8
84.4
76.5
38.5
37.1
Effluent (NTU)
15.3
2.47
1.71
1.79
2.06
1.48
1.11
1.21
1.04
0.92
0.43
0.72
0.94
0.69
0.86
0.48
1.21
0.84
0.72
0.72
0.46
0.8
0.45
0.31
0.81
0.63
0.47
0.41
0.51
0.55
0.38
0.51
2.14
2.08
1.12
1.12
1.12
0.55
0.37
0.27
0.22
0.7
0.97
0.72
0.49
0.46
0.43
G-25
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
3
3
3
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
Date
04/12/2005
04/12/2005
04/12/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/10/2005
01/10/2005
01/10/2005
01/12/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/14/2005
01/14/2005
01/14/2005
01/15/2005
01/15/2005
01/15/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/17/2005
01/17/2005
01/17/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
Influent (NTU)
44.6.5
143
82.7
56.5
230
10.2
90-10
57.4
631
Effluent (NTU)
1.3
1.56
1.91
2.63
2.19
2.25
22.4
8.04
17.2
0.75
1.3
0.57
0.08
1.01
0.44
0.53
0.34
0.35
0.59
1.07
0.52
0.34
0.34
0.39
0.23
0.58
0.34
0.33
0.26
0.12
1.5
0.68
0.26
1.26
0.34
0.56
0.57
0.63
0.85
0.7
0.44
0.5
0.68
0.31
0.24
0.21
0.14
G-26
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS2
4 SYS2
Date
01/19/2005
01/19/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/25/2005
01/25/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
02/08/2005
02/23/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
01/09/2005
01/09/2005
Influent (NTU)
985
533
79
555
550
900
313
317
549
527
433
431
472
530
621
143
Effluent (NTU)
0.26
0.15
2.49
16.9
6.32
1.2
0.8
1.2
1.15
6.38
2.77
1.3
0.86
8.57
2.42
5.23
1.09
1.09
23
1.87
1.45
1.43
1.06
0.65
0.84
1.21
0.69
0.78
0.6
0.74
0.62
0.91
0.51
0.46
0.48
1.07
0.94
0.47
0.61
0.56
0.63
0.53
0.88
1.35
2.77
G-27
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
Date
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/12/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/15/2005
01/15/2005
01/15/2005
01/15/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/17/2005
01/17/2005
01/17/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/25/2005
Influent (NTU)
82.7
56.5
230
10.2
90-10
57.4
631
985
533
Effluent (NTU)
1.07
4.96
.3.4
16.6
2.85
0.9
0.79
1.63
4.63
1.23
1.28
0.41
1.43
3.03
1.53
1.14
0.45
0.48
0.56
1.78
0.33
0.23
0.46
1.2
0.86
0.64
7.25
1.1
0.94
0.51
0.65
0.8
0.48
0.41
0.4
0.49
0.3
1.39
0.25
0.17
0.25
8.69
40
3.97
0.45
0.77
1.5
G-28
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
6
6
6
6
6
6
6
6
6
6
6
6
Date
01/25/2005
01/25/2005
01/25/2005
01/25/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
02/08/2005
02/09/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/24/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/05/2005
03/05/2005
11/8-11/12
11/8-11/12
11/8-11/12
11/8-11/12
11/8-11/12
11/8-11/12
11/14-11/16
11/14-11/16
11/18/2004
12/29/2004
12/29/2004
12/29/2004
Influent (NTU)
79
555
550
900
313
317
549
527
433
431
472
530
621
434
408
308
1000+
672
444
516
951
Effluent (NTU)
0.78
0.62
1.01
1.96
6.48
3.45
1.6
4.84
18.8
4.27
1.2
1.77
9.83
33.2
0.91
8.42
0.94
0.8
0.74
0.66
0.54
0.69
0.78
0.6
0.77
1.61
0.62
1.18
1.64
1.11
0.73
0.78
0.7
0.31
5.9
6.6
4.6
7.1
3.8
7.1
3.9
2.7
1.19
1.53
1.55
G-29
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
Date
12/29/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/23/2005
02/23/2005
02/23/2005
02/25/2005
02/25/2005
02/25/2005
02/28/2005
02/28/2005
02/28/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/04/2005
03/07/2005
03/22/2005
03/23/2005
03/23/2005
03/24/2005
11/13/2005
Influent (NTU)
610
209
517
524
Effluent (NTU)
1.45
0.95
0.46
0.56
0.34
6.03
37.8
45.5
25.4
46.5
6.39
4.52
4.02
2.03
0.43
0.38
0.45
0.26
0.54
0.65
0.83
0.74
0.85
0.7
0.86
2.5
2.53
1.54
1.06
2.7
2.16
1.39
1.46
2.29
1.89
1.23
2.98
1.68
2.27
2.9
2.36
2.39
3.7
2.73
2.74
6.87
G-30
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
6
6
6
6
6
6
6
6
6
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Date
11/13/2005
11/13/2005
11/13/2005
11/13/2005
11/13/2005
11/13/2005
11/13/2005
11/13/2005
11/13/2005
12/20/2004
12/20/2004
12/20/2004
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/03/2005
01/03/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/05/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/07/2005
01/07/2005
01/07/2005
Influent (NTU)
473
473
301
330
295
947
Effluent (NTU)
13
0.1
1.85
0.91
1.47
1.77
1.65
1.79
3.02
0.41
0.38
0.93
0.46
0.69
0.42
0.45
0.56
0.85
0.78
0.92
2.01
8.12
1.12
2.63
2.6
1.95
3.35
3.05
3.89
9.81
13.2
9.2
9.75
8.76
17.8
23.7
22.1
10.8
13.6
3.89
3.94
6.27
10.2
16.6
8.2
9.81
17.2
G-31
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Date
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/12/2005
01/12/2005
01/12/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/14/2005
01/14/2005
Influent (NTU)
923
209
204
over 1000
1000
1000
899
Effluent (NTU)
25.4
27.1
30.1
37.5
7.78
8.51
11.1
13.7
16
12.2
5.92
9.73
6.46
8.21
8.44
9.86
7.65
9.43
8.77
2.32
8.03
11.1
14.1
8.57
6.82
5.26
2.51
4.63
3.16
4.3
11.8
22.8
26.5
28.5
43.1
41
23.7
11.7
24.4
71.6
54.3
38.1
18.6
7.55
42.9
40.6
36.9
G-32
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
8
8
8
8
8
8
8
8
8
8
8
8
8
8
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/15/2005
01/15/2005
01/15/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/16/2005
01/17/2005
01/17/2005
01/17/2005
01/17/2005
03/07/2005
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/29/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/30/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
Influent (NTU)
377
362
86.6
104
108
97.2
86.2
75.5
67
63.7
67.1
106
82.5
78.9
104
106
174
Effluent (NTU)
24.4
10.2
7.91
4.62
6.6
9.36
1.76
0.83
0.37
1.68
1.63
1.81
1.81
0.4
5.07
6.53
7.76
.6.87
0.33
1.2
1.36
1.25
0.62
1.88
1.98
1.13
1.23
13.1
1.31
0.94
1.57
1.58
1.96
2.54
2.38
4.07
6.26
1.12
3.41
5.92
5.46
3.1
3.95
4.08
15.1
15.3
17.8
G-33
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
12/31/2004
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/01/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/02/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/03/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
Influent (NTU)
147
147.8
151.3
148
173
Effluent (NTU)
22.9
31.9
4.02
32.1
22.2
25.6
18.7
20.4
26.4
23.1
20.6
15.6
21.3
22.2
1.54
15.2
26.7
5.26
1.72
1.77
0.89
0.8
0.76
2.47
0.89
0.8
0.76
1.79
2.47
2.11
1.15
0.45
0.72
1.1
0.75
0.58
10.3
14.8
15
11.7
4.35
4.15
23.4
26.3
26.8
33.6
30.6
G-34
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/04/2005
01/05/2005
01/05/2005
01/05/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/06/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/07/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
Influent (NTU)
182
1.56
292
575
269
284
Effluent (NTU)
29.9
30.9
9.09
17.3
4.21
1.33
0.97
1.1
1.12
0.74
0.73
1.08
0.91
0.8
1.85
2.08
2.14
1.02
1.04
9.26
3.8
2.86
2.98
.23
.34
.49
.18
.18
.21
1.1
0.6
1.58
1.31
2.26
2.24
2.12
2.34
3.12
3.98
12.6
15.2
16.6
17.2
10.8
20.5
16.9
1.44
G-35
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/08/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/09/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/10/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
Influent (NTU)
178
191
184
231
230
230
247
204
225
231
230
240
230
267
213
288
Effluent (NTU)
1.36
10
3.61
1.85
6.03
4.39
3.61
3.21
9.48
1.55
2.98
7.57
1.36
1.4
1.86
1.67
1.37
1.26
0.78
0.9
0.51
1.41
1.26
1.26
1.81
1.08
1.21
1.7
1.52
2.37
7.5
5.38
38.7
38.7
6.36
18.5
4.72
16.4
0.9
0.43
0.55
0.74
G-36
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/11/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/12/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
Influent (NTU)
9.99
Effluent (NTU)
0.79
0.54
0.69
0.42
0.46
0.62
0.78
0.71
1.21
0.58
1.22
1.74
1.36
1.79
9.99
7.31
1.63
1.63
2.37
1.57
2.3
1.38
2.44
0.78
0.93
0.64
0.43
0.8
1.35
1.51
1.61
0.89
0.74
0.82
0.94
9.99
24.5
29.6
3.02
0.45
1.25
1.07
0.99
0.31
0.95
2.85
4.05
G-37
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/13/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/14/2005
01/17/2005
01/17/2005
01/17/2005
01/17/2005
01/17/2005
01/17/2005
01/17/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/18/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/19/2005
01/20/2005
Influent (NTU)
Effluent (NTU)
1.6
1.27
0.59
1.13
0.53
0.98
1.07
1.08
2.09
1.16
1.27
2.69
0.68
0.5
0.38
1.1
0.71
.86
.72
.46
.12
.02
.31
.43
.51
.21
.34
0.63
0.76
0.88
3.55
15.3
20.1
1.57
0.49
1.01
1.68
4.37
10.1
2.55
2.34
4.62
1.47
2.58
1.5
1.41
2.24
G-38
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/20/2005
01/20/2005
01/20/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/21/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/22/2005
01/23/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/24/2005
01/25/2005
01/25/2005
01/25/2005
01/28/2005
01/28/2005
01/28/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
01/31/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
02/01/2005
Influent (NTU)
142
213
6
1020
335
6
Effluent (NTU)
.75
.07
.03
3.97
.52
.86
3.97
1.52/.86
1.86/.72
1.18/.85
1.31/.71
.90/.76
.84/.60
1.29/.86
1.17
1.5
0.8
0.66
1.66
0.71
0.21
1
1.78
1.57
1.56
2.1
1.27
1.6
2.66
3
2.1
5.5
5.56
3.12
4.52
5.28
5.11
2.32
2.3
2.14
3.54
3.42
.98
.95
.41
.34
.32
G-39
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/02/2005
02/16/2005
02/16/2005
02/16/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/17/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/18/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
Influent (NTU)
6
214
13.7
99.9
Effluent (NTU)
2.59
2.41
2.34
2.01
1.01
0.98
2.96
7.6
3.8
25.3
0
24/3A97
14.1/.86
8.28A84
1.43/1.46
1.72
.91/1.14
0.59
0.74
0.39
0.48
0.42
0.38
0.44
0.36
0.34
1.43
0.64
0.67
0.48
0.51
0.61
0.73
0.59
0.61
0.69
0.51
0.43
0.41
0.53
0.51
0.42
.397.58
.437.63
.357.86
.29/1.10
.42/1.03
G-40
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/19/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/20/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
Influent (NTU)
28.2
Effluent (NTU)
.43/1.06
.65/.70
1.22/.61
.577.89
.49/1.10
.497.98
0.45
1.22
0.37
0.39
0.38
0.39
0.4
0.45
0.41
1.05
.90/1.14
.60/1.02
.42/1.77
1.26/.33
120/.43
1.12/1.23
.49/1.14
1.0/.69
.62/1.78
.66/1.23
.28
.22
.88
.69
.93
.87
0.98
0.94
0.91
1.28
1.25
.68/1.26
.577.48
.567.59
.617.52
.697.58
.857.54
1.06/.932
1.157.54
1.20/.64
1.64/.83
G-41
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/21/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/22/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/23/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/24/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
02/26/2005
Influent (NTU)
68.2
72
72
87.9
88.6
Effluent (NTU)
0.64
0.66
0.88
0.91
0.68
0.64
0.73
0.85
0.83
0.65
0.63
0.56
.52/1.90
.467.84
.537.85
.97/1.51
.41/1.0
.517.93
.707.53
.937.23
.457.66
.487.22
1.05/1.49
1.197.68
.71/1.11
.96/1.26
.59/1.23
.857.60
.917.95
1.047.97
.62/1.32
.66/1.13
.567.97
.637.79
.43/1.75
.39/2.01
.45/1.08
.57/1.9
.69/4.91
.71/1.55
.49/2.83
.69/1.78
1.98/2.70
.72/1.80
.33/2.01
.36/2.53
.57/2.01
G-42
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
02/26/2005
02/26/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
02/28/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/02/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/03/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/04/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/05/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
03/07/2005
Influent (NTU)
182
1.08
108
72.7
Effluent (NTU)
.43/1.30
.46/1.43
1.27/1.78
1.30/1.70
1.82/2.10
1.16/1.91
.75/1.69
.577.49
.41/.92
1.01/2.47
0/10.6
0/9.01
0/10.5
0/10.2
5.94/10.3
3.49/6.48
3.26/3.83
3.30/3.95
2.61/2.00
3.18/1.22
2.38/1.56
1.09/2.04
1.32/1.60
1.08/1.98
1.28/1.73
.83/1.59
1.13
0.75
1.02
0.82
0.91
0.92
0.96
0.84
0.79
0.84
0.64
0.63
1.15
0.8
0.93
0.83
0.83
1.02
1.98
2.01
1.37
G-43
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
03/07/2005
03/07/2005
03/07/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/08/2005
03/09/2005
03/09/2005
03/09/2005
03/09/2005
03/09/2005
03/09/2005
03/09/2005
511/1
511/1
511/1
511/1
511/1
511/1
511/1
503/1
503/1
503/1
503/1
503/1
503/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
419/1
413/1
413/1
Influent (NTU)
75
77.2
424.9
485.7
666.7
445
19.9
19.5
20
20
20.1
20.1
20.1
20
19.7
166.1
93.9
37.2
37.7
46.1
28.7
160.4
10
62.9
15.9
16
16.2
17.7
11.3
12.6
12.6
Effluent (NTU)
1.27
1.31
0.85
1.27
1.13
1.21
0.86
0.73
0.71
0.87
0.92
3.12
1.04
1.27
2.61
0.94
0.85
1.01
0
0
0
0
0
0
0
0
0
0
0
0
0
9.2
4.9
3.2
3.5
5.4
5
2.6
0.8
1.2
0
0
0
0
0
0
0
G-44
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
413/1
413/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
406/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
326/1
326/1
326/1
326/1
326/1
326/1
Influent (NTU)
12.4
3.8
43.1
43.3
102.2
37.7
39.4
142.2
34
81.2
46.5
47.8
38.2
41.4
26
53.3
64.1
52.5
44.1
40.8
51.7
50.6
31.3
37.6
41.4
49.5
34.7
33
38.1
39.3
37
33.9
28
50.1
77.5
378.4
31.4
32.8
197.1
60.3
23.6
41.8
61.2
52.9
95.6
65.7
63.2
Effluent (NTU)
0
0
6.4
6.4
6
6.1
6.3
6.3
5.5
6.9
6.8
6.9
6.5
6.8
6.3
6.7
4.3
0
3
3.2
2.8
3.1
4
3.8
4
3.6
3.8
3.9
3.6
3.9
3.4
4
3.8
2.2
3
0
0
1.4
1
1.2
0
2.6
.9
.6
.9
.3
.1
G-45
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
326/1
326/1
326/1
326/1
326/1
326/1
326/1
326/1
326/1
326/1
326/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
323/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
321/1
315/1
315/1
Influent (NTU)
141.5
38
57.2
45.8
106.6
71.3
71.9
40
56.7
24.8
40.4
40.9
31.6
78.4
40.1
184.5
19.4
49.9
32
124.7
40.9
101
86.1
47.5
144.5
26
26.1
23
38.6
28.6
72.8
42.8
90.7
21.8
50.3
54.1
54.2
42.9
56.2
30.4
36.2
35.8
36.8
27.7
3.9
16.4
38.1
Effluent (NTU)
2
1.3
1.7
1.5
1.9
2.9
1.2
3.3
2.3
0.7
0.8
1.4
1
0.8
0.8
1.8
0.9
0.5
1.2
0.7
0.9
2.1
0.6
1.3
0.9
0.4
0.4
0.5
0.9
0.4
0.4
1
0.4
0.5
1.6
0.4
0.4
0.4
0.5
0.5
1.9
0.8
1.3
0
0
0.4
1.4
G-46
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
315/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
306/1
Influent (NTU)
71.6
40.2
32.4
27.6
93.7
299.4
33.6
45.2
27.4
45.1
24.2
17.8
3.8
36.8
27.4
95.6
28
34.3
23
24.2
18
38.6
55.2
27.6
23.1
157.9
37.9
27.6
27
36.8
326.8
198.9
40.8
43.2
14.5
23
17.4
39.3
33.1
130.6
49.2
46.4
42.7
75.5
75.4
14.1
6.9
Effluent (NTU)
0.5
1.3
0.8
1.7
6.3
1.1
0.8
1.4
0.8
1.2
1.8
0
0
0.9
1
1.3
1.1
0.9
1.4
0.9
0.9
1.7
1.2
0.9
2.8
1.1
1.5
0.9
0.9
1.8
0
0
1.7
3
0
0.4
0.8
1
0.5
0.7
0.6
0.8
1.6
0.6
0.5
0.8
0
G-47
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
306/1
306/1
306/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
227/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
220/1
Influent (NTU)
4.4
2.5
4
27.7
21.2
47.4
44.1
37.6
20
69.5
64.9
71.9
83.4
108
93.6
90
50
57.5
40.9
9.5
4.3
3.9
4
4.2
4
3.6
135.8
66.1
85
52.2
54.9
160
61.7
93.2
12.4
12
12.3
12.4
12.2
12.4
12.3
12.4
12.2
12.4
8.5
4.1
4
Effluent (NTU)
0
0
0
0
0.5
1.4
0.4
0.9
0.5
1.9
3.7
4.3
3.3
2.4
2.3
1.8
1.9
3.8
3.2
0
0
0
0
0
0
0
0.9
0.5
1.8
0.3
1.5
7.2
1.8
3.3
0
0
0
0
0
0
0
0
0
0
0
0
0
G-48
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
216/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
215/1
208/1
208/1
208/1
208/1
208/1
208/1
208/1
208/1
208/1
208/1
Influent (NTU)
4.3
4.2
4.3
75.1
26.4
26.4
31.2
30
34.3
12.7
86.5
56.7
24
72.4
26.4
20.1
34.7
18
23.5
10.7
0
38.1
29.1
42.8
46.8
41.6
24.8
24.2
27.5
33.1
69.3
43.3
40
24
29.5
38.2
13
21.2
28.7
22.9
18.4
33.5
30.9
63.8
67.8
59.8
26.5
Effluent (NTU)
0
0
0
0
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.5
0.8
0.2
0.2
0.2
0.3
0.3
0
0
1.2
0.5
0.3
0.3
0.4
0.7
0.9
0.3
0.3
0.3
0.4
0.4
1.5
0.6
1.1
0
0.5
0.6
1.6
0.5
0.6
0.6
0.9
1.8
2.6
0.5
G-49
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
208/1
208/1
208/1
208/1
208/1
208/1
208/1
208/1
206/1
206/1
206/1
206/1
206/1
206/1
206/1
206/1
206/1
206/1
206/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
202/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
Influent (NTU)
23.5
149.3
72.9
116
107.2
185.5
12.5
12.7
51.1
36.2
41
44.2
48.1
51
50.7
49.5
45.2
111.1
0
44.9
39.1
40
46.5
46.5
27.6
31.5
40.8
44.4
41.9
60.7
31.8
40.7
48.7
71.5
13
35.3
192.4
26.5
12.4
3.8
28.8
43.4
18
32
31.2
21.2
27.6
Effluent (NTU)
1.5
4.1
3.8
1.6
5.4
0
0.7
1
0.5
0.3
0.4
0.3
0.7
0.9
0.3
0.4
0.6
0
0
0
0.8
0.8
0.8
0.9
1.9
0.9
1
1
0.9
1.1
2.2
2.6
1.8
1.7
0.3
0.4
0
0.9
0
0
1.2
0.3
0.4
0.8
0.3
0.3
0.3
G-50
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
118/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
117/1
109/1
109/1
109/1
109/1
109/1
109/1
Influent (NTU)
26.8
20.3
46
15.8
41.9
23.7
15.2
21.4
11.5
49.9
48
21.3
143.8
27.5
12.3
20.3
13.3
0.3
50.1
27.6
28.1
15.6
20.3
38.1
12.9
50.3
15.6
58.4
19
26.9
18.4
16.3
37.7
52.6
27.1
31.1
19.1
44.7
11.4
12.2
3.7
57.5
13.5
73.3
584.1
67.4
60.8
Effluent (NTU)
0.3
0.3
1.3
0.2
0.3
0.3
0.3
0.3
0.3
0.5
4.1
1.3
2.2
1.2
0.4
0.5
0
0
0
1.1
0.9
0.3
0.3
0.3
0.3
0.4
0.8
0.8
0.3
0.3
0.3
0.3
0.4
0.4
0.9
1.5
0.4
0
1.5
2
0
0.4
0.5
0.9
4.2
0.8
0.5
G-51
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
109/1
109/1
109/1
109/1
109/1
109/1
109/1
109/1
109/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
108/1
106/1
106/1
106/1
106/1
106/1
Influent (NTU)
29.1
185.2
61.2
90.4
55
53.2
30.4
38.8
45.9
3.9
8
60.2
19
98.7
23.5
13.8
37.1
15.9
25.4
178.9
25.8
11.9
21.1
58.4
17.2
72.1
13
18.1
98.3
23.2
53.2
20.2
15.2
37.5
28.8
133.2
21.6
11.4
15.4
10.2
8.9
0
28.2
10.2
25.8
18.1
9.2
Effluent (NTU)
1
0.6
0.7
2.2
0.8
0.5
0.4
1.3
2.1
0
0.2
0.3
0.8
2.4
0.2
0.3
0.3
0.2
0.3
0
0.3
0.3
0.3
1.4
0.2
0.3
0.3
0.3
1.4
0.3
0.3
0.3
0.3
0.4
0.4
0.9
1
0.3
0.4
1
0
0
0
0.2
0.3
1.3
0.2
G-52
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
Date
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
106/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
104/1
103/1
Influent (NTU)
13.8
28.3
18
17.9
10.1
96.5
11.1
29.8
27.8
10.2
22.6
24.2
21.1
19.3
22
23.2
12.8
9.8
10.3
13
17.8
83.7
35.5
26.8
53
59.1
14.8
10
31.6
17.8
21.9
14.4
146.2
9.5
62
20
16.7
21
8.5
78.8
19.3
18.1
16.2
14
27
18.8
20.5
Effluent (NTU)
0.2
0.3
0.3
0.3
0.9
1.4
0.3
0.3
0.3
0.3
0.4
0.4
1.8
0.4
0.6
1.5
0
0
0.2
0.3
0.7
2.1
1.5
0.2
0.3
0.3
0.3
0.2
0.3
0.2
0.3
1
1.3
0.2
0.3
0.2
0.3
0.2
0.2
0.2
0.2
0.7
1
0.2
0.3
0.3
0.2
G-53
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
Date
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
103/1
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
Influent (NTU)
41.9
37
21.1
18.2
54.9
17.5
21.1
13.6
21
10.7
22.3
18.2
24.1
10.1
32.1
31.4
75.5
9.8
15.1
61.9
55.4
14.8
56.5
74.6
91.9
89.8
99.3
32.5
55.5
33.5
46.1
38.3
108.1
709.9
28.9
152.5
17.4
98.4
54.1
58.1
134.8
284
165.1
157.7
158.1
163
156.2
Effluent (NTU)
0.2
0.2
0.2
0.5
0.6
0.5
2
0.5
0.5
0.5
0.5
0.5
0.5
0.8
2.2
0.6
0.6
0.6
0.6
0.9
2.8
3.1
3.9
0
3.7
2.7
1.6
2.3
1
1.1
1.3
2.2
7.3
2.7
3.9
1.4
1.7
4.1
3.2
5.1
0.6
0
2
2.1
2
1.9
1.9
G-54
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
Date
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/06/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/08/2007
01/09/2007
Influent (NTU)
161
159.7
152.8
163
141.7
137.7
143.3
151.7
164.3
155.9
139.2
136.8
144.5
153.9
150.3
135
131.2
142.6
144.3
149.5
149.8
132.1
211.9
2.7
3.6
144.9
140.4
148.9
146.6
140.3
145.9
135.4
143.5
133.8
158.4
150.4
153.1
170.8
170.6
175.5
169.4
171.2
156.5
140.4
135.1
120.5
4.6
Effluent (NTU)
.9
.9
.9
.8
2.2
.4
.5
.5
.5
.5
.6
.7
.7
.7
.7
.7
.7
.9
.9
.9
2.2
2.1
1.8
0
0
2.1
2
1.2
2.1
2.1
2.3
2.2
2.4
3
2.4
2.4
2.7
2.5
2.5
2.5
2.3
2.3
2.5
2.5
2.4
2.4
0
G-55
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
Date
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
01/09/2007
02/09/2007
02/09/2007
02/09/2007
03/02/2007
03/02/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
03/21/2007
05/11/2007
05/11/2007
05/11/2007
05/11/2007
05/11/2007
05/11/2007
05/11/2007
Influent (NTU)
180.3
135.8
117.8
123.6
129.3
113.9
107.4
108.3
170.5
119.7
122.4
128.9
136.6
133
128.5
135.5
136
131.9
139.7
136.1
130
132.5
126.8
114.2
113.8
99.5
17.1
13.5
25.2
11.6
13.8
62
64.1
61.5
53.9
44.9
24.7
7.2
5.9
37.2
39.4
34
32.5
37.3
20.5
16.5
19.3
Effluent (NTU)
0
.6
.6
.6
.6
.6
.8
.9
.7
.5
.8
.9
.7
.6
.2
.6
.6
.8
.8
.8
.9
2
2.1
2.2
2.1
0
1.1
1.5
1.8
0
0.9
2.8
2.9
2.7
2.4
2.2
2.1
0.6
1
1.9
2.7
3
3
1.8
1.5
1.5
1.5
G-56
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
BWWTP
BWWTP
BWWTP
BWWTP
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
ELLRD
ELLRD
ELLRD
Date
05/11/2007
05/14/2007
05/14/2007
05/14/2007
01/15/2008
01/16/2008
01/16/2008
01/16/2008
01/16/2008
01/16/2008
01/17/2008
01/17/2008
01/17/2008
01/17/2008
01/18/2008
01/18/2008
01/18/2008
01/18/2008
01/18/2008
01/18/2008
01/18/2008
01/21/2008
01/25/2008
01/28/2008
01/28/2008
01/29/2008
01/29/2008
01/29/2008
01/29/2008
01/29/2008
01/29/2008
01/29/2008
01/30/2008
01/30/2008
01/30/2008
01/30/2008
01/30/2008
01/30/2008
01/30/2008
02/04/2008
02/04/2008
02/04/2008
02/04/2008
02/04/2008
05/03/2005
05/03/2005
05/03/2005
Influent (NTU)
37.3
37.6
35.8
8.6
380
420
417
317
246/306
348
282
149
6.22
6.24
6.02
Effluent (NTU)
1.9
6
4.3
1.6
2.21
1.75
2.03
1.26
1.08
0.64
1.47
0.78
0.52
2.34
0.81
1.11
0.85
0.56
0.56
0.59
1.8
1.4
0.49
6.5
0.9
0.84
0.69
0.5
0.38
0.42
1.4
0.49
0.92
0.52
0.21
0.22
0.26
2.1
0.98
1.02
0.67
0.75
3.81
1.59
1.25
G-57
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
Influent (NTU)
6.09
6.33
6.42
6.65
7.11
7.17
6.5
6.62
9.78
10.78
10.07 *
8.97*
7.98*
7.29
6.89
6.62
6.87
6.84
7.21
7.65
7.63
7.42
7.57*
7.57*
7.79*
8.12
18.87
19.25
16.63
10.6
8.55
8.23
8.44
9
9.78
17.74
15.17
13.23
11.7
11.09
10.7
10.23
9.86
9.48
9.13
8.9
15.23
Effluent (NTU)
1.33
1.43
1.53
1.61
1.8
1.76
1.78
1.78
4.39
1.52
1.72*
1.77*
1.89*
2
2.07
2.29
3.44
3.71
2.72
2.76
2.79
2.76
2.82*
2.78*
3.49*
4.48
4.81
3.22
2.73
3.92
3.11
3.01
3.18
3.43
3.71
3.92
3.67
3.95
9.61
5.44
5.43
4.36
4.21
4.11
4.01
3.92
3.56
G-58
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/03/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
Influent (NTU)
10.63
9.58
8.99
10.25
10.52
9.94
9.39
9
8.77
8.63
8.59
8.84
9.95
9.57
19.83
16.5
12.81
10.97
10.03
9.53
9.41
9.96
15.79
13.33
11.21
9.97
9.23
8.86
8.78
8.85
25.49
15.88
13.14
11.33
10.53
10.21
10.07
9.96
12.23
12.54
11.08
8.89
7.73
7.59
7.92
7.46
7.37
Effluent (NTU)
5.2
4.63
4.83
4.16
3.45
3.31
3.39
3.5
3.6
3.66
3.71
3.84
7.06
5.55
5.35
5.04
4.59
4.41
4.55
4.66
4.78
7.59
5.63
4.98
4.37
4.31
4.28
4.27
4.26
4.27
6.16
4.6
4.7
4.94
5.09
5.23
5.32
5.27
6.77
1.32
1.6
1.37
2.61
1.87
2.46
2.5
2.68
G-59
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
Influent (NTU)
7.36
7.3
7.29
7.3
7.3
7.28
8.35
8.83
14.46
15.36*
12.27
10.85
10.13
9.32
9.03
9.14
8.82
8.61
8.58
8.56
8.57
8.56
8.61
8.57
9.45
10.64
15.54
15.48
13.38
11.87*
10.65 *
10.17
9.82
9.66
9.54
9.5
9.51
13.34
11.67*
11.07
10.5
10.32
10.2
10.1
10
9.94
9.92
Effluent (NTU)
2.84
2.98
3.13
3.26
3.37
3.46
3.58
6.82*
7.05
4.55
4.8
4.85
4.92
4.49
4.66
4.78
8.83
8.76
4.61
4.59
4.62
4.66
4.68
4.72
5.24
7.61
7.9
6.07*
6.06*
6.14
5.46
5.7
5.85
5.97
6.08
6.15
11.82*
6.6
7.1
6.08
5.45
5.42
5.52
5.64
5.74
5.86
5.93
G-60
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/04/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
Influent (NTU)
9.88
9.64
9.61
9.52
11.77
12.24
11.11
10.39
9.93
9.67
9.53
9.51
9.56
9.78
9.78
9.84
11.37
11.6
11.12
10.59
10.32
10.18
10.14
10.1
10.09
10.2
9.99
10
10.05
10.08
10.15
10.29
13.38
11.4
9.5
8.42
7.61
7.1
6.83
6.64
6.53
6.48
7.33
9.96
9.24
7.57
6.99
Effluent (NTU)
6.01
7.01
8.62
6.14
6.12
5.19
4.48
4.27
4.32
4.45
4.63
4.85
5.07
6.73
6.44
8.23
5.3
5.15
5.21
5.37
5.54
5.71
5.87
6.03
6.15
7.96
6.9
6.38
5.62
5.52
5.47
5.52
6.03
3.17
1.44
1.32
1.41
1.56
1.73
1.88
2.02
2.14
2.4
3.87
4.19
3.52
3.36
G-61
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
Influent (NTU)
6.68
6.51
6.42
6.41
6.35
6.98*
11.55
9.47
7.94
7.35
6.96
6.84
6.82
6.81
6.82
7.11
7.86
7.58
7.24
7.11
6.95
6.96
6.78
6.81
6.73
7.94
7.77
7.45
7.17
7.05
7.02
7.12
7.09
7.34
24.85
18.11
13.99
11.35
9.95
9.09
8.57
8.21
7.92
7.84
7.63
7.67
7.48
Effluent (NTU)
3.36
3.39
3.41
3.42
3.41
3.73*
3.26
3.29
4.64
4.66
3.84
3.62
3.65
3.69
3.69
4.07
3.25
3.31
3.44
3.53
4.81
5.57
4.11
3.81
3.75
3.46
3.49
3.57
3.66
3.77
3.9
3.96
5.31
5.91
4.5
5.58
5.56
5.58
5.52
5.4
5.29
5.18
5.07
4.89
6.58
6.66
4.76
G-62
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/05/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
Influent (NTU)
7.74
8.27*
10.83
9.1
8.31
7.86
7.62
7.51
7.6
7.55
13.23
12.93
10.63
9.45
8.71
8.36
8.12
8.05
8.02
7.65
7.84
14.74
16.4
12.91
8.36
8.54
8.24
8.27
8.25
8.2
8.25
8.2
8.19
8.22
7.37
26.11
28.35
22.26
19.5
15.05 *
16.59*
33.38*
34.27
17.45
10.98
8.13
7.48
Effluent (NTU)
4.52
4.42*
4.11
3.99
4.05
4.18
4.3
4.42
4.47
6.05
5.54
2.72
2.45
2.55
2.7
2.87
3.04
3.19
3.31
3.4
3.47
5.21
5.9
5.27
4.56
4.49
4.5
4.65
4.59
4.65
4.64
4.55
4.55
4.71
4.72
0.37
0.46
1.89
1.04
1.11 *
1.13*
1.16*
0.89
0.74
0.77
0.9
2.3
G-63
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/09/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
Influent (NTU)
7.82*
22.01 *
18.95
11.16
7.67
6.09
5.08
4.63
4.6
4.52
5.23*
5.28*
22.49
11.89
7.7
5.77
4.86
4.45
4.23
4.06
13.2
10.38
7.43
5.95
5.06
4.66
4.43
4.27
4.2
4.24
5.04
8.17
25.52
11.27
7.86
5.81
5.86
4.43
4.34
5.93
6.94
16.73
20.35
19.09
17.61
16.39
14.14
Effluent (NTU)
1.33*
1.24*
0.85
0.8
0.8
0.82
0.9
1.04
1.76
1.36
1.42*
1.45*
0.86
0.79
0.81
0.83
0.91
1.03
1.18
1.35
1.61
0.89
0.89
0.9
0.91
0.97
1.05
1.15
1.27
1.39
1.53
2.48
0.67
0.64
0.66
0.86
1.72
1.07
1.15
1.1
1.07
1.04
0.83
0.81
1.03
1.28
3.2
G-64
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
Influent (NTU)
13.19
12.48
11.89
12.14*
16.5
14.07
13.09
12.27
12.05
11.97
11.86
11.68
15.11
13.82
14.08
12.86
12.41
12.13
11.98
11.99
12.07
11.88
11.79
11.68
11.63
11.67
11.78
11.93
12.11
12.38
12.53
13.36
12.99
13.17
14.5
15.97
15.41
16.66
18.47
17.12
16.21
15.33
14.25
13.93
14.65 *
14.87*
15.06*
Effluent (NTU)
3.06
2.53
2.84
3.42*
1.73
1.58
1.62
1.78
2.09
2.56
2.96
3.39
3.17
3.43
3.12
2.29
2.13
2.35
2.66
3
3.4
3.08
2.57
2.63
2.92
3.39
3.95
4.31
4.7
4.68
4.46
4.6
3.26
3.3
2.31
1.95
2.24
2.28
3.72
2.61
2.2
2.02
2.45
2.88
3.72*
4.26*
4.42*
G-65
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/11/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
Influent (NTU)
15.46*
15.12*
14.45
14.09
13.76
13.47
13.28
13.02
13.43 *
65.32
32.11
21.33
16.83
14.91
14.07
13.91
15.22
15.88
14.59
13.09
12.12
11.58
11.25
11.11
11.01
11.2*
32.26
18.27
14.82
12.39
11.75
11.68*
25.71
16.6
12.79
11.95
11.41
11.13
10.97
10.97
11.41
10.87
10.83
10.77
10.72
10.68
Effluent (NTU)
4.22*
6.47*
2.76
2.45
2.39
2.72
3.17
3.66
5.84*
6.36
9.26
4.87
4.5
3.63
3.29
3.73
4.69
1.17
1.86
3.13
2.5
2.25
2.56
2.92
3.3
3.67
4.96*
2.78
4.39
5.95
3.91
3.82
3.74*
1.96
2.13
2.51
3.12
3.66
4.05
4.48
4.88
4.56
3.28
2.82
2.49
2.64
2.94
G-66
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
Influent (NTU)
10.95
11.33
10.9
10.77
10.73
10.73
12.1
11.53
11.3
11.08
10.98
10.89
10.85
11.11 *
11.47*
11.5
11.02
10.95
11.13
10.86
10.97
10.94
10.87
10.79
10.7
10.66
11.07
13.09
12.01
11.2
11.2
10.91
11.15
11.21
10.84
10.8
10.77
10.82
12.15
14.58
13.07
12.22
11.59
11.28
11.09
11.02
10.96
Effluent (NTU)
3.25
2.47
2.81
3.24
3.67
4.07
4.74
3.14
2.62
2.14
2.43
2.92
3.34
4.31 *
4.09*
1.59
2.01
2.66
4.12
3.46
2.68
2.21
2.39
2.74
3.11
2.84
2.22
3.33
2.71
2.2
2.82
2.92
2.62
2.36
2.59
2.92
3.26
3.57
1.86
1.76
2.54
3.2
3.72
4.12
4.47
4.84
5.21
G-67
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
Influent (NTU)
10.97
10.88
11.78*
14.89
12.72
11.67
11.36
11.15
11.04
10.97
10.96
11.03
49.13
27.64
18.08
15.95
16.65
17.39
14.34
13.08
12.4
11.9
11.62
11.5
11.59*
16.78
15.66
13.69
12.84
12.15
11.71
12.13
11.62
11.55
11.52
11.53
11.6
11.66
11.99*
13.39
13.3
12.8
13.13
12.58
12.15
12.06
12.11
Effluent (NTU)
4.69
4.35
4.53*
1.93
1.91
2.22
2.57
2.98
3.39
3.77
4.15
4.45
3.56
7.49
6.46
2.8
4.08
3.28
2.49
2.71
3.16
3.56
3.94
4.29
4.54*
2
2.27
3.12
3.81
4.37
8.66
3.86
3.09
2.52
2.87
3.27
3.82
4.13
5.17*
1.69
2.28
2.88
3.31
2.95
2.23
3.93
3.07
G-68
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/12/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
Influent (NTU)
11.99
11.96
11.97
11.96
11.94
8.03
11.75
12.1
12.76
13.07
13.31
13.43
13.18
13.21
13.04
12.87
12.77
12.67
12.58
12.82
13.52
15.31
14.71
13.59
12.63
12.11
11.84
11.73
11.73
11.69
11.57
11.49
11.95
11.81
11.73
11.76
11.72
11.71
11.67
19.5
16.4
14.43
14.11
12.9
12.31
12.17
12.18
Effluent (NTU)
2.45
2.55
2.92
3.34
3.72
2.64
2.82
2.6
1.84
2.59
3.09
3.8
2.53
4.35
4.99
5.41
5.54
5.74
5.84
5.84
7
3.47
2.38
2.58
3.05
3.6
4.08
4.49
4.78
4.98
5.14
5.19
5.22
5.53
4.58
3.23
3.19
3.24
3.27
1.52
2.7
2.39
2.38
2.04
2.24
2.6
2.94
G-69
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/13/2005
05/16/2005
05/16/2005
05/16/2005
Influent (NTU)
12.17
12.08
11.97
11.84
12.5
12.18
12.19
12.61
11.87
11.92
11.74
11.85
16.72
13.29
12.7
12.48
12.28
12.34
12.4
12.63
13.19*
14.97
21.82
22.38
21.53
20.77
20.53
20.86
20.61
20.19
20.51
21.38
22.28
23.13
24.13
24.93
25.86*
26.76 *
27.45 *
32.47 *
47.96
36.68
33.57
32.55 *
14.86
23.84
29.2
Effluent (NTU)
3.3
3.7
4.02
4.25
4.33
4.53
4.77
2.42
2.25
2.3
2.55
2.87
3.29
1.23
1.93
2.62
3.35
4
4.46
4.71
16.52*
4.47
2.64
2.09
5.85
3.26
2.69
3.15
4.07
4.98
5.76
6.69
7.5
8.28
9.06
9.79
10.54*
11.33 *
11.98*
87.79 *
8.24
7.29
8.03
10.11 *
4.84
7.99
7.92
G-70
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
Influent (NTU)
32.69 *
35.46 *
36.82 *
37.9*
38.63
38.91
39.03 *
40.4*
40.13
40.63
40.78
78.57
62.77
54.31 *
48.71
44.76
42.33
41.01
40.1
39.48 *
39.25
39.95
39.61
39.86
40.16
40.43
42.05
41.77
41.35
40.76
40.6
40.34
40.9
40.96
42.23
43.63
45.96
48.07
51.16
53
55.28
56.51
57.26 *
57.61
57.81
58.1
60.67
Effluent (NTU)
12.5*
17.22 *
21 *
17.98 *
5.35
8.61
11.79*
14.3*
8.08
5.94
4.55
2.85
9.73
66.23 *
3.06
3.24
1.27
2.28
4.64
35.38*
3.94
4.34
2.95
3.88
6.16
9.14
7.01
1.23
1.76
0.9
1.94
4.53
3.3
1.85
1.31
2.54
5.45
5.98
4.86
3.61
4.84
8.58
33.13 *
8.04
4.8
4.34
1.86
G-71
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/16/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
Influent (NTU)
61.54
61.44
63.76
66.89
70.83
73.81
77.28 *
80.13
83.68 *
86.8
89.44 *
90.83 *
90.17*
90.4
86.07
80.72
74.96
70.95 *
69.23
69.18
68.6
66.35
62.54 *
63.56
61.96*
61.44
61.72
63.11
64.71
67.64
33.5
31.58
30.41
34.36
35.44
33.55
32.29
31.75
31.53 *
32.51
32.08
32.57
33.12
33.14
33.06
33.12
Effluent (NTU)
5.67
4.39
1.92
1.93
3.62
9.05
17.93 *
8.29
11.8*
7.46
14.42 *
18.49*
53.13 *
9.46
3.41
2.73
6.51
19.97 *
7.49
3.19
3.28
6.23
48.81 *
8.9
13.56*
1.52
2.93
2.59
7.01
9.38
2.86
5.23
6
8.35
7.4
8.24
8.94
9.31
9.88
14.76 *
4.83
2.05
0.94
1.38
2.27
3.65
5.26
G-72
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
Influent (NTU)
33.24
35.04
33.14
34.05
34.32
34.77
34.95
35.3
35.61
35.48
35.61
34.99 *
34.6*
33.36
33.16
32.53
32.46
87.63
105.8
59.05 *
39.34
80.08
67.75
51.58
44.31
41.35
40.13
38.99
38.35
36.77
39.95
36.59
35.92
35.76
36.24
35.61
34.07
32.94
31.7
30.97
31.48
35.44
38.93
40.68
40.37
43.07
40.72
Effluent (NTU)
7.01
8.76
7.45
1.43
1.6
1.3
2.28
3.81
5.6
7.46
9.15
10.59*
11.75 *
3.32
0.79
1.7
0.57
0.9
3.56
40.86 *
0.6
1.75
0.13
0.13
0.27
0.82
1.72
2.78
3.97
6.13
2.33
0.74
0.48
0.47
0.62
1.02
1.82
2.7
3.5
4.36
5.38
5.88
1.75
0.58
0.59
0.73
1.05
G-73
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
Influent (NTU)
41.78
42.12
37.92
36.01
36.26
35.42
35.98
36.11
36.65
37.13 *
37.11 *
36.81
37.61
37.34
37.86
38.21
38.81
39.39
39.41
39.55
39.86
40.73
42.18
42.86
43.46
43.65
45.4*
45.57*
43.4*
59.03 *
66.62 *
63.11
59.21
58.72
59.04
59.37
58.8
58.68
62.95
62.26
63.46
64.71
66.03
64.87
65.38
65.81
65.86
Effluent (NTU)
0.75
1.24
2.06
3.08
4.14
5.38
6.8
8.19
9.65
11.03 *
12.21 *
3.02
0.83
1.6
0.58
0.86
1.58
3.45
1.89
1.33
0.78
1.26
2.47
4.43
6.66
8.84
10.54*
14.22 *
14.48 *
15.55 *
35.22 *
4.55
1.58
1.26
2.98
6.65
7.61
6.77
5.36
3.07
6.82
5.52
1.24
0.53
0.51
0.38
0.36
G-74
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/18/2005
05/20/2005
05/20/2005
05/20/2005
Influent (NTU)
62.92
54.63
49.34
48.81
47.03
46.73
45.65
61.83
71.7
69.09
64.74
59.82
50.17
82.43
88.17
85.03
87.19
88.05 *
91.17*
98.12*
101.73
103.82
104.71
103.68
75.82
67.4
98.73
106.07
102.6
101.01
102.3
105.99*
112.64
115.41
118.44
121.02
116.71
112.21
79.25
71.01
107.13
120.34
121.46
127.5
39.13
36.71
95.16
Effluent (NTU)
0.56
1.09
1.62
0.63
0.54
0.52
0.53
0.56
0.35
0.68
1.41
2.99
2.12
3.55
0.93
1.3
4.33
11.41 *
20.28 *
21.69*
2.16
0.78
0.63
0.95
2.14
3.16
1.16
0.43
0.48
1.02
3.86
10.62 *
2.05
1.01
0.82
2.33
7.97
7.85
0.84
0.48
0.46
0.35
2.74
7.26
3.06
1.53
0.84
G-75
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
Influent (NTU)
108.87
111.36
110.45
106.65
107.1
104.94
106.83 *
92.95 *
74.01
85.98
107.25
102.66
101.65
102.32 *
101.47*
101.18
103.13
101.62
100.44
77.16
85.7
98.56*
94.85 *
94.64
95.13
95.3
94.97
95.8
72.45
57.97
89.08
92.25
93.75
93.18
93.17
98.37
100.7
100.64
83.83
61.67
85.5
102.41
107.87
111.97
114.36
120.65
119.43
Effluent (NTU)
2.46
2.49
1.22
3.08
2.69
7.97
18.15 *
27.25 *
4.55
0.59
1.39
0.43
3.56
15.56*
29.07 *
8.96
1.26
3.3
2.83
6.53
8.62
21.5*
11.59*
7.56
0.69
0.55
0.65
1.98
1.51
0.67
0.7
0.37
0.34
2.39
1.36
0.66
0.52
0.87
0.79
0.7
1.09
0.4
0.59
1.41
0.76
1.26
1.78
G-76
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
Influent (NTU)
119.68
84.58
66.53
108.4
114.07
111.5
118.95
122.34
123.87
120.14
120.34
85.89
65.36
117.14
116.4
114.89
117.39
119
119.79
117.3
111.79
76.7
56.09
99.08
114.11 *
117.59*
124.6 *
128.05 *
129.92 *
132.25 *
130.56*
133.54*
133.58
138.42
123.14
80.8
86.53
125.45 *
135.13
140.54 *
143.47 *
150.02*
153.01 *
161.42*
154.85 *
115.03*
87.06
Effluent (NTU)
3.44
0.78
0.48
0.48
0.6
1.29
1.15
1
2.66
2.05
0.64
0.93
0.58
0.75
1.43
1.65
1.81
3.29
1.38
1.12
1.17
0.97
0.78
0.88
16.86*
47.43 *
74.66 *
88.62 *
97.11 *
104.34 *
109.29 *
111.42*
8.8
1.01
3.6
6.54
7.2
24.48 *
9.66
12.89*
15.17*
122.84 *
34.4*
11.35 *
15.82*
53.6*
4.28
G-77
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
Influent (NTU)
152.22
149.56
150.58*
147.74 *
156.28
163.34
154.16
80.86
50.05
125.28
125.89
138.94
138.95
146.97
156.84
154.44
80.78
49.22
135.26
135.02
138.49*
137.05
143.29
151.79
150.05
75.39
47.41
122.33
141.53
136.42
137.21
150.34
163.26
154.69
88.07
50.65
149.71
157.11
154.81 *
154.47
171.53
168.71
161.48
78.32
48.92
136.92
147.28
Effluent (NTU)
2.52
2.23
12.82 *
14.33 *
5.73
9.4
6.43
1.65
0.89
1.3
4.2
4.6
4.79
7.58
5.55
3.93
3.79
1.56
0.77
2.4
14.57*
5.34
7.69
6.11
5.38
1.22
1.87
0.9
7.51
4.33
6.58
6.76
6.26
5.89
5.29
1.48
1.49
2.08
13.92*
6.37
9.54
7.39
7.8
2.64
0.83
1.61
3.16
G-78
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/20/2005
05/21/2005
05/21/2005
05/21/2005
Influent (NTU)
143.49
153.64
165.19
163.36
145.69
69.06
47.94
158.27
161.09
165.29
169.42
175.23
182.77
130.34
62.66
116.91
164.27
165.45 *
162.93
174.66 *
174.91 *
168.5
100.83 *
51.04
122.37
135.15
134.61
149.3 *
167.1 *
142.32
63.52
66.41
158.08
148.68
163.98
173.36
181.18*
128.13
73.28
137.67
167.76
158.24
168*
166.47
133.58*
63.97
124.18
Effluent (NTU)
7.12
5.57
5.37
6.67
4.61
2.05
0.88
1.11
3.12
5.82
8.34
4.67
2.23
7.28
1.47
0.62
1.87
12.35 *
4.5
16.77 *
15.09*
2.41
10.41 *
1.98
1.01
0.53
2.83
22.51 *
16.72 *
8.11
4.73
1.22
2.67
5.08
7.36
7.23
10.75 *
6.89
1.74
1.52
2.66
7.51
12.42 *
5.29
12.97 *
5.32
1.34
G-79
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
Influent (NTU)
163.4*
160.33 *
167.53 *
147.86*
67.19*
26.82
22.62
22.96
97.25
125.54*
66.47 *
26.59
21.29
96.05
105.52*
98.15 *
37.49 *
20.46 *
18.5
80.54
126.51 *
136.47*
109.74 *
60.01 *
20.27
17.25
19.28
19.72 *
118.53*
133.35*
131.82*
58.59*
18.81 *
14.44
14.27
18.74
16.21 *
109.09 *
125.18*
85.72 *
25.22 *
20.73 *
13.39*
16.79 *
102.08 *
139.29*
126.64 *
Effluent (NTU)
11.66*
33.61 *
57.53 *
70.94 *
40.84 *
5.82
0.75
0.38
0.4
23.34 *
29.61 *
5.48
2.11
9.37
40.08 *
37.13 *
24.32 *
10.06 *
9.51
3.51
30.92 *
54.8*
62.54 *
44.01 *
8.94
1.66
1.01
11.26*
50.92 *
64.48 *
70.88 *
47.31 *
12.91 *
3.28
1.42
1.23
13.77*
36.98 *
68.41 *
70.2*
38.22 *
19.64 *
17.49 *
15.47*
26.69 *
100.75 *
124.84 *
G-80
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
Influent (NTU)
27.55 *
33.95 *
25.94 *
21.76*
21.79*
21.61 *
21.73 *
21.31 *
21.44*
21.55 *
18.05 *
58.74
44.74
20.01
13.76
11.78
10.56
9.09
9.57
8.51
9.26
9.13
9.08
8.39
8.58
8.01
7.64
8.17*
10.37
31.6*
134.24 *
133.88*
146.97 *
137.27*
86.34 *
156.37*
177.92 *
196.69 *
70.41
67.51
69.69
72.82
69.87
68.87
70.84
68.97
67.53
Effluent (NTU)
52.17*
16.22 *
16.3*
15.97*
15.52*
16.23 *
16.45 *
15.67*
14.54 *
14.25 *
11.86*
4.47
0.23
0.3
0.36
0.49
0.32
0.32
0.34
0.36
0.37
0.39
0.38
0.41
0.36
0.33
0.29
98.76 *
5.62
11.22*
35.75 *
88*
111.29*
117.7*
44.06 *
73.82 *
151.75*
164.06 *
0.21
0.21
0.21
0.21
0.22
0.22
0.22
0.24
0.25
G-81
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
Influent (NTU)
72.46
71.91
70.72
69.67
67.93
66.82
126.19
86.38 *
94.08
103.43 *
184.98 *
186.83 *
180.82*
177.48 *
157.15*
98.26
62.08
156.25
180.75
171.12*
164.73 *
164.34 *
170.51 *
111.36
59.12
139.37
160.98
151.42*
156.72*
160.07
150.42 *
77.33
45.28
160.61
152.45 *
158.56*
140.69 *
83.03
30.15
23.77
143.4
156.27*
148.21 *
148.6*
147.99 *
136.67*
66.54 *
Effluent (NTU)
0.25
0.25
0.25
0.25
0.25
0.25
0.25
38.53 *
7.13
15.71 *
50.69 *
24.85 *
18.46*
29.97 *
20.95 *
7.5
5.3
6.48
6.71
15.9*
36.46 *
61.75 *
75.46 *
9.92
5.94
3.88
8.05
20.85 *
25.53 *
5.71
22.09 *
6.75
1.61
4.23
10.61 *
23.57*
15.69*
5.27
2.14
8.57
6.3
23.4*
45.1 *
38.04 *
14.25 *
25.04 *
18.88*
G-82
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/21/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
Influent (NTU)
41.32
141.84
147.8 *
150.08*
135.41
141.25*
80.62 *
36.14
60.21 *
19.08
90.11
101.73
101.32
103.99
93.7
95.05
40.22
80.38
99.74
98.35
89.48
78.01
40.79
34.86
115.74
114.84
104.72 *
101.61
99.05
97.23
98.61
82.27
64.41
103.04
100.34
97.99
98.04
96.31
101.99
95.95
65.88
96.21
98.78
99.22
94.84
96.21
94.83
Effluent (NTU)
3.28
5.21
24.77 *
26.56 *
7.06
21.48*
23.91 *
6.04
10.12*
6.34
2.47
7.14
5.34
1.62
3.87
5.01
1.51
0.36
7.1
5.08
0.26
0.83
0.53
0.76
3.02
6.25
19.32*
4.04
7.86
6.92
9.77
9.83
1.8
2.14
6.3
5.12
7.28
6.74
1.97
4.73
1.17
1.48
4.28
1.97
4.42
6.63
1.93
G-83
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/22/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
Influent (NTU)
94.78
84.6
56.81
97.66
102.33
92.92
94.58
91.17
90.8
90.36
72.62
48.21
95.08
95.46
87.35
88.06
90.48
91.26
89.49
64.02
66.6
92.87
92.43
91.07
93.42
94.11
83.15
52.1
99.49
97.58
93.6
88.64
88.24
86.72
89.16
88.1
66.34
47.21
93.27
87.29
85.67 *
83.19*
87.67 *
85.66 *
68.79 *
40.73 *
79.54 *
Effluent (NTU)
5.39
3.34
6.07
1.35
1.2
5.38
5.72
2.38
4.67
1.35
4.73
1.6
1.64
5.24
1.5
2.91
4.69
2.72
6.17
0.98
1.11
2.12
2.28
7.05
4.73
0.36
1.48
4.1
1.2
3.85
8.73
2.25
4.39
2.69
2.36
3.9
1.5
1.37
2.41
8.54
20.43 *
29.71 *
38.78 *
45.67 *
46.26 *
27.3*
23.9*
G-84
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
Influent (NTU)
81.86*
83.83 *
85.75 *
80.37 *
41.7*
84.33
86.17*
86.67 *
83.75 *
84.57 *
51.34*
32.37
88.81
91.27*
86.13 *
82.51 *
72.62
33.69
76.87
84.05
84.77
85.23
62.65
38.67
89.29 *
97.24
84.07
87.7
87.62
89.48
73.9
45.76
92.16
91
85.55
88.81
83.8
85.1
77.24
49.31
85.44
91.36
84.65
81.39
83.92
83.36
85.99
Effluent (NTU)
37.18*
22.92 *
13.54*
13.43 *
11.73 *
7.16
28.62 *
37.48 *
45.35 *
42.82 *
22.86 *
2.75
6.97
20.88 *
34.1 *
33.78 *
2.59
8.64
0.43
0.3
1.73
0.44
3.58
4.03
30.64 *
3.38
1.95
6.2
2.54
7.27
5.25
0.68
0.97
5.29
3.93
6.68
5.45
2.5
0.67
2.72
1.7
2.14
5.47
3.02
2.46
3.53
4.62
G-85
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
Influent (NTU)
59.8
59.8
86.29
81.86
82.98
85.15
83.65
83.97
70.03
44.53
83.59
82.23
80.87
80
80.62
82.33
50.81
71.21
86.78 *
80.36
77.85 *
78.76 *
77.99
81.55 *
71.75 *
50.89
87.11
78.26 *
78.53
75.3
78.31 *
76.57
79.15
67.02
44.9
84.38
80.43 *
80.33
78.31
76.03 *
78.78
78.03 *
50.54
68.3
79.25
79.37
73.57
Effluent (NTU)
2.53
3.29
1.89
2.65
6.99
4.08
0.94
4.94
3.55
1.68
1.96
6.52
2.25
7.26
5.55
0.88
5.19
4.69
24.02 *
5.41
17.64 *
14.66 *
9.74
12.9*
12.44 *
6.67
3.86
29.04 *
3.56
7.07
20.49 *
3.27
7.27
9.88
1.42
7.06
26.87 *
3.83
7.59
11.1 *
3.58
15.63 *
7.56
2.27
6.99
9.79
7.42
G-86
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
Influent (NTU)
73.78
76.18*
77.65
47.7*
22.57
72.45
73.99
67.8
73.74 *
72.1
76.58
33.59*
23.61
18.4
84.65
83.72 *
76.12
77.04 *
74.85
76.27
63.79
41.32
74.6
74.04
69.51 *
69.19
69
71.13
70.99
57.04
35.92
74.83
69.81
67.07
63.83
67.78
64.36
66.46
68.49
65.64
49.24 *
65.29 *
71.22*
70.12*
66.88
62*
Effluent (NTU)
8.85
10.63 *
4.41
10.61 *
1.26
4.2
9.51
3.62
10.25 *
9.41
2.97
5.27*
4.08
0.34
9.75
14.24 *
5.32
10.82*
3.22
8.25
5.04
2.07
2.98
4.49
10.37*
2.7
8.29
4.83
6.35
5.57
5
3.47
1.67
9.34
7.46
3.49
5.62
6.13
8.05
4.02
18.26*
24.45 *
24.64 *
33.9*
8.08
2.22
11.33 *
G-87
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
Influent (NTU)
66.64
64.71
63.39*
66.56
63.68
63.75
62.32
59.99
61.53
57.82
58.43
59.71
56.67
59.25
62.23
63.03
58.63
62.41
59.65
60.09
59.97
61.4
56
59.3
62.66
59.96
58.35
58.17
60.08
62.63
59.68
58.45
62.44
60.71
58.42
59.94
58.09
57.74
59.91
57.98
60.39
56.57
57.31
56.15
57.54
55.81
56.28
Effluent (NTU)
8.29
4.85
10.81 *
2.01
6.87
4.48
2.23
3.74
6.41
7.28
2.55
4.72
4.04
4.1
6.28
2.21
5.1
3.23
2.32
2.49
2.85
1.56
3.87
4.31
5.46
2.32
2.37
1.61
2.84
4.35
0.87
1.46
1.2
0.76
1.18
2.24
3.89
1.18
1.87
2.48
1.17
1.83
4.46
1.06
1.99
3.06
1.06
G-88
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/23/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
Influent (NTU)
55.84
58.24
58.2
56.13
56.81
47.91
44.51
45.6
10.33
10.59
11.38
11.94
11.75
11.77
12.18
12.63
12.76
12.27
12.57
20.38
16.91
28.59
54.23
51.73
48.22
45.98
46.15
50.55
46.44 *
48.84 *
47.23 *
47.33 *
45.81 *
45.79 *
46.82 *
46.02 *
46.12*
46.58 *
46.67 *
45.65 *
52.54
51.7
48.59
46.55
46.08 *
44.88
44.74
Effluent (NTU)
1.94
4.35
0.92
6.97
1.72
1.25
1.3
0.85
0.26
0.26
0.26
0.27
0.26
0.26
0.27
0.28
0.28
0.28
0.28
1.75
1
3.9
1.69
0.57
0.76
2.6
1.57
9.99
16.84*
17.1 *
19.93 *
14.77 *
19.91 *
21.96*
39.53 *
29.39 *
32.11 *
31.36*
20.6*
13*
1.45
1.76
4.68
9.12
12.35 *
4.21
0.31
G-89
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
Influent (NTU)
45.37
44.56
44.54
44.35
45.06
44.18
44.47
44.39
45.02
43.53
45.36
45.46
45.23
44.43
47.85
45.31
46.01
46.29
45.43
43.84
44.57
43.7
43.15
43.06
43.14
42.67
43.84
44.06
42.4
43.55
44.5
42.1
44.19
43.43
44.47
43.65
18.61
28.25
27.69
36.85
44.71 *
56.9
52.86
48.05
49.2
48.45
45.04
Effluent (NTU)
2.55
0.41
0.68
1.7
3.72
5.53
0.56
0.61
1.01
1.71
0.46
1.08
1.74
0.37
0.34
0.33
0.84
2.56
5.72
8.8
2.51
0.41
0.34
0.46
0.88
1.77
1.48
0.44
0.78
0.51
0.78
1.26
1.74
1.11
0.38
0.39
1.66
0.38
0.51
0.55
0.62*
0.76
1.15
2.31
1.11
0.61
0.75
G-90
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
Influent (NTU)
42.39
41.51
41.16
40.85
39.86
40.65
39.61
39.88
39.7
40.02
38.9
38.95
38.66
38.54
38.89
38.76
38.31
37.98
39.25
37.81
38.07*
39.39
37.89*
38.13 *
38.1 *
37.17*
37.13 *
38.15 *
36.91
37.14
37.07
36.78
37.68
37.34
37.91
38.95
37.36
37.13
37.56
38.04
37.12
37.7
36.81
37.31
38.88
37.5
36.97
Effluent (NTU)
1.24
2.23
3.72
2.49
0.59
0.51
0.6
0.89
1.45
1.85
1.32
0.48
0.44
0.52
0.82
1.11
2.63
7.26
8.14
8.17
11.44*
8.1
12.09 *
15.6*
18.06*
20.68 *
22.3*
11.2*
0.71
0.71
0.5
0.77
1.51
2.98
4.91
5.59
0.65
0.5
0.42
0.53
1.18
2.3
5.44
1.34
4.07
0.65
0.68
G-91
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
05/24/2005
Influent (NTU)
37.56
36.71
36.58
36.47
36.3
37.78
37.15
37.32
37.41
36.61
36.89
36.18
36.52
36.49
36.16
36.8
36.31
36.24
36.11
35.86
36.55
36.06
36.17
36.22
36.48
36.21
36.34
35.85
35.08
36.98
36.03
36.6
36.46
36.69
36.27
35.95
35.01 *
35.82
35.18
35.35
35.33
34.97
35.05
34.54
33.94 *
34.36
34.36
Effluent (NTU)
1.2
2.39
4.27
6.33
2.07
0.68
0.77
0.69
1.24
2.33
4.14
6.25
2.21
0.62
1.85
0.57
0.96
2.04
3.79
5.58
5.89
3.13
0.63
0.52
0.69
1.35
2.8
4.8
8.51
1.21
1.14
0.52
0.6
1.1
2.25
3.98
21.83 *
1.11
1.95
0.5
0.52
0.83
1.64
3.09
22.47 *
0.95
2.1
G-92
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/24/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
Influent (NTU)
34.28
12.54
40.13
43.72
41.4
39.18*
37.52 *
50.51 *
42.59 *
37.37
36.64 *
36.31
34.83 *
34.9*
34.42 *
33.82*
33.87*
33.52*
33.42 *
35.82*
33.94
35.04
34.52
34.87
34.51
34.22
33.37
33.27
35.17
32.48
33.39
32.41
32.4
32.19
33.93
33.96
33.92
34.87
31.27
31.87
30.67
30.67
30.67
31.12
31.4
33.41
59.41
Effluent (NTU)
2.16
3.73
2.38
5.93
5.75
10.07 *
13.51 *
19.44 *
11.82*
2
10.43 *
7.16
10.64 *
13.68*
16.74 *
18.77*
17.06 *
18.89*
19.4*
15.13 *
5.78
0.48
0.8
0.42
0.87
1.97
3.8
5.78
7.65
2.77
0.46
0.71
0.4
0.69
1.44
2.78
4.28
5.9
2.02
0.42
0.69
0.34
0.48
0.98
1.94
3.35
6.6
G-93
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
Influent (NTU)
46.59
40.72
36.11
33.66
33.35
31.6
30.02
30.29
32.08
31.59
32.97
32.3
31.96
32.02
31.94
31.92
31.54
34.36
31.35
32.99
31.58
30.92
31
30.91
30.92
30.72
28.48
27.78
29.39
29.78
29.46
28.78
29.02
28.69
27.71
30.13
29.1
29.82
29.68
30.57
30.42
30.71
31.29
32.3
30.54
29.97
29.78
Effluent (NTU)
2.28
2.83
0.56
0.89
1.27
1.58
1.42
0.32
0.36
0.6
0.44
0.59
0.44
0.75
1.56
2.97
4.71
6.33
3.12
0.5
0.8
0.43
0.63
1.21
2.36
3.69
1.83
1.51
0.74
0.47
0.6
1.16
2.22
3.58
5.7
1.74
1.02
0.95
2.9
5.65
8.31
7.75
7.97
7
2.47
0.93
0.65
G-94
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
Influent (NTU)
29.03
28.97
29.17
28.49
29.86
29.53
29.92
29.75
30.2
30.16
32.52
30.74
31.41
30.91
30.54
30.73
30.74
31.26
33.27
32.02
33.23
32.78
32.25
31.87
32.1
31.49
32.25
33.21
33.32
35.3
36.73
37.73 *
39.56
42.03
45.24
49.18
53.96*
57.12*
57.71 *
57.34 *
54.96
53.4*
55.56*
62.44 *
71.96*
76.02 *
80.33 *
Effluent (NTU)
0.89
1.42
2.29
7.79
1.21
1.17
0.65
0.74
1.12
1.84
2.83
2.22
0.72
0.9
0.63
1
1.73
2.8
4.3
0.87
0.88
0.64
1
1.79
2.89
1.36
0.68
1.6
0.66
1.26
2.65
24.39 *
2.11
2.97
1.55
4.33
11.24*
19.56*
11.16*
11.38*
5.69
10.36*
16.05 *
20.15 *
35.01 *
28.54 *
39.05 *
G-95
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/25/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
Influent (NTU)
85.52*
96.74 *
106.44 *
108.96*
103.79*
94.61 *
85.82*
9.08
11.14
68.05
78.08
129.21 *
99.44
80.62
77.17
72.9
69.79 *
66.53 *
64.66 *
88.34
79.92
70.34
65.22
61.79*
62.69 *
60.27
61.37
51.36
30.5
11.76
54.91
17.8
16.82
54.68
68.97 *
75.31 *
73.67 *
70.56 *
64.69
62.51 *
61.16
58.76*
57.67
57.81
57.57
58.65
59.57
Effluent (NTU)
39.14*
57.81 *
66.61 *
69.5*
62.27 *
98.89*
45.42 *
8.26
1.46
1.11
8.32
30.16*
0.67
3.14
0.34
2.31
13.54*
19.78 *
11.32*
2.99
3.06
7.84
6.57
12.63 *
12.53 *
3.29*
6.08*
6.13
5.76
2.64
3.32
0.44
1.62
4.66
22.26 *
20.17*
32.23 *
31.58*
8.73
11.51 *
5.53
10.6*
3.38
3.56
2.02
4.37
3.08
G-96
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
05/26/2005
Influent (NTU)
58.62
57.13
53.42
55.21
52.98
53.88
54.32
52.26
51.5
51.02
50.52
51.66
50.64
51.32*
51.99*
49.83 *
51.61
51.77
52.13
51.64
50.41
49.35
35.58
42.55
64.45
62.32
58.04
55.4
54.67
54.13
54.75
53.97
50.96
53.52
51.26
50.26
49.39
51
50.87
51.57
50.7
50.15
50.32
49.88 *
49.19*
48.56*
47.11
Effluent (NTU)
1.96
1.63
1.71
1.64
1.4
2.46
6.06
4.08
2.92
1.55
3.27
0.84
4.65
13.6*
21.56*
66.28 *
1.8
0.69
0.68
1.68
0.64
0.86
0.94
1.14
0.76
1.4
1.2
2.58
1.01
0.76
1.49
0.83
2.07
0.88
0.85
0.7
0.92
1.6
1
1.03
0.83
1.18
1.92
14.25 *
11.18*
16.79 *
2.44
G-97
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/26/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/27/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
Influent (NTU)
45.74
14.46 *
7.64
15.03
30.37
62.79
62.12
54.25 *
45.94 *
40.16*
41.15 *
38.12*
38.3*
37.11 *
48.02 *
48.42 *
43.68 *
62.08 *
41.82*
42.03 *
37.53 *
39.02 *
42.36
38.39*
35.31 *
33.54*
31.3*
30.86*
33*
31.16
34.36
35.3
37.01
34.56 *
34.58 *
32.51 *
31.74*
34.03 *
32.36
2.14
2.11
2.13
2.13
2.11
2.12
2.12
2.09
Effluent (NTU)
0.41
26.75 *
0.38
0.8
0.47
0.53
1.5
11.79*
18.85 *
20.89 *
19.65 *
11.81 *
14.93 *
10.57*
16.34*
11.98*
19.54*
14.25 *
16.51 *
20.3*
10.94 *
13.02*
8.84
12.06 *
14.31 *
16.28 *
18*
19.06 *
16.27 *
7.25
8.14
5.18
8.05
11.18*
14.07 *
16.7*
18.6*
16.31 *
7.29
0.2
0.2
0.2
0.21
0.21
0.21
0.21
0.21
G-98
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
Influent (NTU)
2.13
2.12
2.14
2.15
2.14
2.16
2.12
1.82
45.77
13.03
15.36
22.31
18.2
16.17
13.75
12.19
11.66
12.2
11.54*
12.43 *
14.82 *
26.33 *
39.87*
16.23 *
27.96 *
21.36*
21.16*
11.04*
12.78 *
11.62
10.83
10.06
19.61
14.11
12.07
11.62
12.1
12.7
12.87
14.67
27.24 *
30.38 *
17.47
14.28
12.47
11.65
11.08
Effluent (NTU)
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
0.21
1.75
0.94
0.8
0.9
0.87
1.15
0.41
0.59
1.48
2.95*
3.88*
4.53*
4.97*
5.14*
6.16*
6.39*
7.82*
6.43*
12.85 *
10.12*
6.24
6.25
7.52
8.01
6.01
6.47
7
7.46
7.73
7.94
7.96
8.59*
8.23*
9.17
7.17
7.62
9.51
7.17
G-99
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/30/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
Influent (NTU)
11.07
11.09
10.98
11.16
11.25
12.79 *
21.65
15.83
12.28
11.94
11.27
10.68
10.92
8.1
9.17
8.75
8.27
7.72
7.5
6.95
6.56
6.34
6.21
6.52
6.44
6.1
6.04
6
6.04
5.89
5.89
6.12
7.69*
7.81
8.02
8.37
8.33
8.3
9.63
9.96
19.7
14.77
14.75
23.01
21.87
14.5
16.24 *
Effluent (NTU)
7.3
7.35
7.36
7.37
7.42
8.55*
8.56
9.97
8.31
7.2
6.94
7.05
7.19
6.91
8.27
6.94
6.07
5.74
5.56
5.44
5.3
5.25
7.53
5.51
5.93
5.03
4.95
4.89
4.89
3.73
1.68
0.92
0.59*
0.86
0.8
0.79
0.77
0.74
0.73
0.71
0.72
0.87
1
0.95
0.86
4.93
12.63 *
G-100
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
Date
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
Influent (NTU)
15.48
15.23 *
15.63
23.99
12.8
12.18
9.51
9.39
7.99
8.51
7.53
7.49
7.93
7.86
7.66
7.68
7.64
7.61
7.53
7.47
7.4
14.5
11.69
9.06
8.29
7.78
7.52
7.48
7.46
7.61
19.36
13.99
11.24
10.5
9.15
8.99
9.04
8.34
8.29
8.54
8.71
8.71
8.8
79.65
65.27
41.35
16.07
Effluent (NTU)
7.69
23.95 *
1.21
1
1.27
0.19
0.16
0.16
0.18
0.23
0.3
0.34
0.42
0.75
0.68
0.74
0.78
0.8
0.79
0.79
0.84
0.69
0.43
0.23
0.2
0.23
0.32
0.44
0.58
0.74
0.98
0.38
0.32
1.15
0.37
0.44
0.66
0.83
0.88
0.89
0.87
0.85
0.83
0.16
0.23
0.56
0.18
G-101
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
HEO
HEO
HEO
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
05/31/2005
01/14/2000
02/02/2000
02/09/2000
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/10/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/11/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
03/12/2003
Influent (NTU)
16.06
8.16
8.59
7.53
7.34
7.33
7.43
7.47
7.52
7.46
696
650
466
161
172
170
175
162
177
164
170
165
141
160
177
142
160
151
182
170
188
152
170
161
188
176
165
232
248
198
248
235
249
262
261
247
273
Effluent (NTU)
0.18
0.24
0.35
0.48
0.59
0.71
0.79
0.82
0.82
0.82
25.2
25
13.95
1.4
1.1
1.22
1.11
1
1.08
1.22
1.14
1.08
0.98
1.33
1.2
2.4
2.76
2.72
2.08
2.46
2.64
2
3.2
2.48
2.46
1.98
1.9
3.08
2.51
2.98
3.75
4.05
3.27
2.05
2.31
3.09
0.86
G-102
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
03/12/2003
03/12/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/13/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/17/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/21/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/24/2003
03/31/2003
03/31/2003
03/31/2003
03/31/2003
03/31/2003
03/31/2003
Influent (NTU)
283
264
608
575
633
714
621
571
572
602
631
575
611
562
222
220
251
239
215
264
211
188
203
133
152
140
144
134
150
142
130
135
192
220
199
181
197
164
152
147
171
147
154
121
137
153
127
Effluent (NTU)
1.1
2.68
3.28
3.1
3.84
3.24
2.88
2.77
3.08
3.74
3.38
4
3.35
3.28
2.19
2.31
2.2
0.98
1.12
1.48
1.76
1.39
0.99
2.91
1.26
1.72
2.65
1.89
1.26
2.61
2.08
1.84
2.61
2.43
3.31
1.75
1.02
1.11
1.03
0.79
1.23
1.17
1.7
1.52
1.41
1.7
1.82
G-103
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
03/31/2003
03/31/2003
03/31/2003
04/02/2003
04/02/2003
04/02/2003
04/02/2003
04/02/2003
04/02/2003
04/04/2003
04/04/2003
04/04/2003
04/04/2003
04/04/2003
04/04/2003
04/09/2003
04/09/2003
04/09/2003
04/09/2003
04/09/2003
04/09/2003
04/10/2003
04/10/2003
04/10/2003
04/10/2003
04/10/2003
04/10/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
11/18/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
Influent (NTU)
143
119
132
195
237
223
210
194
236
74
79
82
63
73
76
127
136
142
123
132
171
209
188
210
241
275
260
99
117
235
372
482
612
703
789
917
173
154
92
108
106
102
107
123
118
112
143
Effluent (NTU)
0.87
1.22
1.4
2.14
1.94
2.06
2.11
1.75
1.6
1.37
1.5
1.42
1.18
0.88
1.08
0.96
1.12
1.3
1.75
0.77
1.26
1.17
1.46
2.02
0.89
1.75
1.15
4.96
4.73
4.69
5.18
4.89
4.72
4.17
5.13
4.89
4.92
4.63
4.67
4.87
4.92
4.28
4.37
4.93
4.87
4.23
4.82
G-104
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
1 1/29/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/01/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/02/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/03/2003
12/04/2003
12/04/2003
Influent (NTU)
132
116
152
187
163
177
103
100
90
101
89
100
88
95
98
88
90
93
99
89
93
83
93
88
77
82
74
84
81
97
94
83
87
242
225
181
198
193
192
185
197
132
147
150
163
132
137
Effluent (NTU)
4.17
4.67
4.82
4.72
4.54
4.97
4.27
3.72
4.28
3.87
4.17
4.62
3.54
4.32
4.83
3.76
3.94
4.79
4.12
4.53
4.37
3.82
4.38
3.52
1.34
4.66
1.42
3.87
1.98
1.83
2.49
2.18
3.82
1.89
2.51
1.19
1
1.43
1.33
2.13
2.35
2.17
2.63
3.17
2.92
1.82
1.48
G-105
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/04/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
12/05/2003
Influent (NTU)
133
151
163
153
187
162
143
167
173
217
235
183
207
187
235
192
219
243
183
151
143
217
237
287
212
182
162
172
150
193
217
189
150
173
197
217
269
225
273
159
151
159
172
152
165
153
163
Effluent (NTU)
2.12
2.47
2.89
1.92
1.69
1.47
1.39
1.56
1.87
2.37
1.93
2.26
2.49
2.09
2.89
2.47
3.17
3.68
2.07
1.65
1.82
2.04
2.73
2.91
2.37
1.97
2.73
2.65
1.85
2.21
2.08
2.42
2.07
2.46
2.92
3.27
3.52
2.87
1.92
2.88
2.44
2.44
2.59
2.55
2.35
3.46
2.43
G-106
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
12/05/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/06/2003
12/09/2003
12/09/2003
12/09/2003
12/09/2003
12/09/2003
12/09/2003
12/09/2003
12/09/2003
12/10/2003
12/10/2003
12/10/2003
12/10/2003
12/10/2003
12/10/2003
12/11/2003
12/11/2003
12/11/2003
12/11/2003
12/11/2003
12/11/2003
12/11/2003
12/11/2003
12/15/2003
12/15/2003
Influent (NTU)
232
172
183
169
151
163
174
219
192
163
174
218
159
146
182
179
157
168
184
217
187
172
183
68
65
59
61
72
65
59
75
88
69
75
68
72
77
50
65
46
44
52
51
54
56
287
271
Effluent (NTU)
3.17
3.12
2.72
2.47
3.18
3.47
2.84
1.89
2.28
2.82
3.12
3.62
2.83
2.87
3.17
2.73
3.62
3.24
3.54
3.29
2.89
2.47
2.31
4.68
3.48
1.29
2.41
2.84
3.37
2.63
2.83
3.23
4.19
4.62
3.36
2.73
3.17
3.45
1.82
1.23
4.62
3.82
3.27
3.64
3.78
4.32
3.62
G-107
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
12/15/2003
12/15/2003
12/15/2003
12/16/2003
12/16/2003
12/16/2003
12/16/2003
12/16/2003
12/17/2003
12/17/2003
12/17/2003
12/17/2003
12/17/2003
12/22/2003
12/22/2003
12/22/2003
12/22/2003
12/22/2003
12/23/2003
12/23/2003
12/23/2003
12/23/2003
12/24/2003
12/24/2003
12/24/2003
12/24/2003
12/24/2003
12/24/2003
12/26/2003
12/26/2003
12/26/2003
12/26/2003
12/26/2003
12/26/2003
12/26/2003
12/29/2003
12/29/2003
12/29/2003
12/29/2003
12/29/2003
12/29/2003
12/30/2003
12/30/2003
12/30/2003
12/30/2003
12/30/2003
12/30/2003
Influent (NTU)
269
264
269
171
174
180
198
172
228
184
189
207
162
143
182
173
169
192
182
193
207
188
123
147
162
178
162
169
189
217
237
224
218
203
231
143
145
152
142
161
151
169
158
161
145
152
146
Effluent (NTU)
1.58
2.43
3.47
3.62
1.38
2.55
0.76
1.96
1.92
1.93
2.17
2.53
1.83
3.19
3.62
4.92
3.85
3.92
3.11
2.88
3.61
3.07
2.07
2.15
4.45
3.93
3.47
2.48
2.39
3.12
3.58
3.61
3.12
2.14
2.73
2.14
1.68
1.9
2.17
2.3
2.37
2.61
2.79
2.1
2.04
1.81
3.66
G-108
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
12/30/2003
01/02/2004
01/02/2004
01/02/2004
01/02/2004
01/02/2004
01/02/2004
01/02/2004
01/02/2004
01/05/2004
01/05/2004
01/05/2004
01/05/2004
01/05/2004
01/05/2004
01/06/2004
01/06/2004
01/06/2004
01/06/2004
01/06/2004
01/06/2004
01/06/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/08/2004
01/09/2004
01/09/2004
01/09/2004
01/09/2004
01/09/2004
01/09/2004
01/09/2004
01/12/2004
01/12/2004
01/12/2004
01/12/2004
01/12/2004
Influent (NTU)
149
148
149
146
143
142
156
148
148
263
282
291
276
258
328
427
407
398
362
319
337
312
269
257
258
256
268
318
282
291
268
151
254
311
288
254
268
281
324
267
291
282
252
251
262
252
247
Effluent (NTU)
2.2
4.06
2.29
3.18
1.96
2.41
2.12
1.69
3.99
3.67
4.1
3.83
3.17
2.87
4.17
3.17
3.62
3.19
2.85
2.64
2.84
2.16
2.53
3.96
4.27
3.62
3.87
3.28
2.71
2.89
3.82
4.76
4.83
4.62
3.85
3.11
3.37
3.18
3.92
3.38
2.98
3.42
3.54
4.27
2.43
4.41
4.29
G-109
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
01/12/2004
01/12/2004
01/12/2004
01/12/2004
01/13/2004
01/13/2004
01/13/2004
01/13/2004
01/13/2004
01/13/2004
01/13/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/14/2004
01/15/2004
01/15/2004
01/15/2004
01/15/2004
01/15/2004
01/15/2004
01/15/2004
01/15/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/16/2004
01/19/2004
01/19/2004
01/19/2004
Influent (NTU)
253
238
258
267
241
245
247
252
254
241
272
238
245
238
258
241
244
243
307
257
258
311
351
327
296
294
302
310
312
332
328
309
304
312
290
286
288
298
281
295
282
280
317
292
228
217
226
Effluent (NTU)
3.62
3.42
3.84
3.17
3.67
4.09
3.67
2.68
3.64
4.67
3.87
2.96
3.18
3.23
2.81
3.18
2.96
3.72
3.95
4.51
3.62
3.24
3.83
4.17
3.91
4.36
4.5
3.85
4.18
3.76
4.16
2.66
2.62
3.2
2.64
3.57
3.68
2.7
3.35
4.74
3.94
3.62
3.82
3.67
4.47
4.19
3.92
G-110
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
01/19/2004
01/19/2004
01/19/2004
01/19/2004
01/19/2004
01/19/2004
01/19/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/20/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/21/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/22/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/23/2004
Influent (NTU)
241
232
235
227
237
224
253
217
225
216
233
241
261
283
317
272
284
312
308
319
317
272
218
237
227
204
231
324
287
312
345
311
261
284
311
269
294
249
228
258
312
337
311
262
248
267
289
Effluent (NTU)
4.36
3.62
3.48
3.86
4.91
3.82
2.98
3.08
3.2
3.61
4.63
4.61
3.22
2.98
3.74
3.47
3.18
3.72
3.27
2.89
3.27
3.19
2.99
3.24
3.58
2.62
3.27
4.17
3.65
4.39
4.08
3.63
3.23
3.67
3.15
2.89
3.08
3.58
3.81
3.49
2.63
3.9
2.85
3.41
3.87
3.62
3.92
G-lll
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
01/23/2004
01/23/2004
01/23/2004
01/23/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/26/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/27/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/28/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
Influent (NTU)
251
267
318
328
507
496
498
510
517
485
481
503
498
491
501
517
532
386
419
386
392
384
404
385
422
402
371
418
375
412
401
382
443
382
392
411
382
380
375
443
452
501
678
587
552
613
625
Effluent (NTU)
4.05
3.62
4.28
3.87
4.63
4.52
3.86
3.56
3.09
3.04
3.78
4.27
3.84
4.85
3.61
4.19
3.92
4.09
4.97
2.77
3.77
2.7
3.12
3.06
3.82
2.79
3.46
3.08
3.11
2.92
2.8
3.17
4.43
3
3.29
3.17
4.24
3.7
3.58
3.97
4.36
4.17
3.17
4.57
4.23
4.82
3.89
G-112
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/29/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/30/2004
01/31/2004
01/31/2004
01/31/2004
01/31/2004
01/31/2004
01/31/2004
01/31/2004
02/02/2004
02/02/2004
02/02/2004
02/02/2004
02/02/2004
02/02/2004
02/02/2004
02/03/2004
Influent (NTU)
652
722
809
633
690
697
718
700
652
631
683
658
632
581
561
528
611
578
463
514
543
589
562
489
617
463
418
398
361
316
312
351
308
322
308
321
364
411
459
490
487
485
498
480
468
475
269
Effluent (NTU)
4.61
3.5
4.72
4.74
1.99
2.86
2.89
4.03
3.42
3.19
3.47
4.17
3.81
3.92
4.29
3.83
4.71
3.88
2.69
3.85
3.64
3.25
3.71
3.62
3.63
3.75
3.89
3.42
3.89
3.23
3.45
3.87
3.59
3.18
3.68
4.18
4.32
3.64
3.11
2.42
3.07
3.43
3.61
2.83
2.42
2.68
2.15
G-113
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
02/03/2004
02/03/2004
02/03/2004
02/03/2004
02/03/2004
02/03/2004
02/03/2004
02/04/2004
02/04/2004
02/04/2004
02/04/2004
02/04/2004
02/04/2004
02/04/2004
02/04/2004
02/05/2004
02/05/2004
02/05/2004
02/05/2004
02/05/2004
02/05/2004
02/05/2004
02/05/2004
02/06/2004
02/06/2004
02/06/2004
02/06/2004
02/06/2004
02/06/2004
02/06/2004
02/06/2004
02/07/2004
02/07/2004
02/07/2004
02/07/2004
02/07/2004
02/07/2004
02/07/2004
02/11/2004
02/11/2004
02/11/2004
02/11/2004
02/11/2004
02/11/2004
02/11/2004
02/11/2004
02/12/2004
Influent (NTU)
279
251
272
259
267
308
327
268
271
261
276
275
293
307
284
261
259
261
270
293
287
271
338
317
293
261
308
302
311
284
309
327
342
367
372
361
358
362
187
172
175
193
182
168
189
176
178
Effluent (NTU)
1.79
2.07
3.58
3.09
3.92
3.67
2.82
3.19
4.07
3.39
3.18
3.61
2.99
2.37
2.45
4.36
4.56
2.43
1.28
3.11
2.91
3.19
2.96
2.65
3.26
3.62
3.04
2.73
2.87
3.61
2.87
2.67
3.19
3.67
3.52
3.18
3.41
3.18
1.37
2.62
3.12
4.19
3.64
3.19
2.84
3.12
1.28
G-114
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
02/12/2004
02/12/2004
02/12/2004
02/12/2004
02/12/2004
02/12/2004
02/16/2004
02/16/2004
02/16/2004
02/16/2004
02/16/2004
02/16/2004
02/16/2004
02/16/2004
02/17/2004
02/17/2004
02/17/2004
02/17/2004
02/17/2004
02/17/2004
02/17/2004
02/17/2004
02/18/2004
02/18/2004
02/18/2004
02/18/2004
02/18/2004
02/18/2004
02/18/2004
02/19/2004
02/19/2004
02/19/2004
02/19/2004
02/19/2004
02/19/2004
02/23/2004
02/23/2004
02/23/2004
02/23/2004
02/23/2004
02/23/2004
02/23/2004
02/23/2004
02/25/2004
02/25/2004
02/25/2004
02/25/2004
Influent (NTU)
171
175
181
173
175
164
184
191
176
188
197
181
193
178
167
174
182
174
184
172
184
173
148
146
139
133
128
132
139
99
92
97
96
92
95
143
148
137
141
132
135
142
131
243
241
254
248
Effluent (NTU)
2.67
1.32
4.21
4.05
3.61
3.43
2.79
3.22
3.48
3.27
2.89
2.64
3.42
2.96
3.69
4.68
2.89
3.48
3.82
3.19
2.12
2.33
4.25
2.92
4.41
4.56
3.16
3.64
3.18
2.44
2.18
3.19
2.87
2.97
3.03
2.83
3.12
3.43
2.87
2.17
2.04
2.72
2.28
3.18
2.91
3.04
3.47
G-115
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
02/25/2004
02/25/2004
02/25/2004
02/25/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
02/27/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/01/2004
03/02/2004
03/02/2004
03/02/2004
03/02/2004
03/02/2004
03/02/2004
03/02/2004
03/02/2004
03/03/2004
03/03/2004
03/03/2004
03/03/2004
03/03/2004
03/03/2004
03/03/2004
03/04/2004
03/04/2004
03/04/2004
03/04/2004
03/04/2004
03/04/2004
03/04/2004
03/04/2004
03/05/2004
03/05/2004
Influent (NTU)
263
268
252
261
453
451
450
447
450
449
452
439
417
182
197
173
185
178
194
211
184
167
142
142
140
141
143
145
143
151
197
202
196
193
187
194
184
299
302
298
290
275
274
317
307
306
325
Effluent (NTU)
3.52
3.11
3.84
3.22
4.46
3.89
3.8
3.49
3.41
3.16
3.28
3.42
3.17
2.38
2.93
3.18
2.87
3.37
2.82
3.47
3.24
3.46
3.86
3.42
2.87
3.36
3.87
2.89
4.14
3.82
4.47
3.47
3.17
3.42
3.17
2.82
3.72
4.2
2.76
3.57
3.21
2.75
3.53
4.69
3.42
3.13
4.19
G-116
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
Date
03/05/2004
03/05/2004
03/05/2004
03/05/2004
03/05/2004
03/05/2004
03/08/2004
03/08/2004
03/08/2004
03/08/2004
03/08/2004
03/08/2004
03/08/2004
03/08/2004
03/09/2004
03/09/2004
03/09/2004
03/09/2004
03/09/2004
03/09/2004
03/09/2004
03/09/2004
03/22/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/23/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/24/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
03/25/2005
Influent (NTU)
331
325
343
361
332
358
242
225
208
220
215
236
241
243
217
223
203
213
223
231
243
232
237
311
331
224
Effluent (NTU)
3.89
3.62
2.72
3.18
3.84
4.11
2.76
1.51
1.64
3.49
1.22
2.48
2.17
3.18
3.42
2.84
2.61
2.47
2.17
2.39
2.17
2.48
0.62
0.15
0.23
0.21
0.37
0.33
0.22
0.24
0.25
0.03
0.29
0.37
0.61
0.52
0.58
0.3
1.85
0.7
0.39
0.24
0.92
G-117
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC05
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
Date
03/25/2005
03/25/2005
03/25/2005
03/26/2005
03/28/2005
03/28/2005
03/28/2005
03/28/2005
03/29/2005
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/07/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/1 1/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/12/2008
02/13/2008
02/13/2008
02/13/2008
02/13/2008
02/13/2008
02/13/2008
Influent (NTU)
210
220
926
923
234
406
906
996
867
755
742
782
761
765
736
735
819
819
822
746
754
730
737
718
699
731
742
757
630
698
698
688
669
649
638
675
615
631
Effluent (NTU)
0.6
0.31
0.34
0.3
0.51
1.03
0.33
0.57
0.32
4.42
0.79
3.51
5.79
1.79
7.3
0.88
2.27
0.49
0.58
0.59
0.63
0.59
0.68
0.44
1.42
0.48
1.21
6.29
0.21
1.23
0.26
0.19
0.26
0.16
0.25
0.33
0.22
0.22
0.57
1.2
2.68
0.47
1.04
0.79
0.33
G-118
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
Date
02/13/2008
02/13/2008
02/13/2008
02/13/2008
02/13/2008
02/13/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/14/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/15/2008
02/16/2008
02/16/2008
02/16/2008
02/16/2008
02/16/2008
02/16/2008
02/16/2008
02/16/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
02/17/2008
Influent (NTU)
659
657
471
618
629
641
629
645
1000+
1000+
1000+
1000+
1080
1080
Effluent (NTU)
0.38
0.36
0.31
0.35
0.38
0.033
0.47
3.5
1.87
1.25
3.54
1.45
1.6
2.5
1.75
1.73
2.91
2.74
1.64
3.09
1.09
1.51
1.36
0.59
0.31
0.4
0.44
0.62
0.88
0.78
1.66
1.4
0.7
0.34
0.25
4.86
0.53
1.39
0.82
0.36
0.33
0.53
1.72
0.37
0.72
0.86
1
G-119
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
02/17/2008
02/18/2008
02/18/2008
02/18/2008
02/18/2008
02/18/2008
02/18/2008
02/18/2008
02/19/2008
02/19/2008
02/19/2008
02/19/2008
02/19/2008
02/20/2008
02/20/2008
02/20/2008
02/20/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/23/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
02/24/2008
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
Influent (NTU)
808
839
1536
408
1022
556
387
928
905
907
1000+
1000+
171.54*
56.41
127.68
Effluent (NTU)
1.74
1.17
0.72
0.65
0.68
1.06
0.81
2.54
3.73
0.27
1.2
0.67
0.84
2.01
0.47
2.49
0.47
0.96
0.79
1.42
1.24
0.47
0.44
0.41
0.35
0.3
0.34
0.51
0.51
0.51
1.61
2.5
0.78
0.38
0.34
0.64
0.37
0.59
1.68
0.66
0.45
1.63
10.04 *
1.15
0.84
1.07
2.33
G-120
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
Influent (NTU)
138.01
136.12
136.75
138.79
138.16
116.48
113.94
134.03 *
144.07
145.42
145.16*
126.08 *
120.36
137.15
149.65
157.7
148.28
126.78
120.95
139.15
158.03
154.1
129.96
Effluent (NTU)
6.87
0.9
0.82
7.34
1.2
1.85
0.65
1.63
8.22
0.49
1.29
0.68
0.6
0.57
0.7
17.09 *
0.5
0.46
1.93
0.59
1.13
0.48
14.27 *
11.88*
0.44
0.87
0.7
0.77
0.8
1.25
5.9
0.49
0.47
1.65
0.56
1.1
0.92
0.99
0.63
1.89
0.55
0.55
4.83
1.12
0.88
0.76
0.79
G-121
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
Influent (NTU)
126.86
138.07
150.14
157.22
165.5
136.84
126.45
143.77*
164.92
169.73
159.02
137.03
133.54
153.83*
168.05 *
173.66
148.51
140.8
142.1
155.52*
166.43 *
170.27
135.32
116.33
Effluent (NTU)
1.74
0.69
0.54
5.98
2.3
3.8
2.42
4.96
6
0.6
1.96
1.11
1.24
1.33
2.7
19.36*
0.77
1.05
6.19
7.43
9
3.11
2.88
1.65
3.73
2.95
18.1 *
2.25
11.24*
5.22
5.95
6.54
4.27
2.67
5.2
3.39
6.67
9.49
9.19
15.42 *
7.84
13.29*
3.68
7.97
2.93
2.29
1.33
G-122
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
Influent (NTU)
119.09
121.32
127.89
121.41
118.48
110.94
112.23
124.24
127.88
117.92
109.68
113.36
119.21
123.75
112.59
114.96
110.16
113.52
121.99
127.39
119.59
108.24
113.61 *
Effluent (NTU)
0.82
1.12
0.96
1.19
0.98
0.65
0.49
0.56
0.5
1.03
2.91
0.9
0.58
0.56
0.53
0.51
5.99
0.49
0.83
0.7
0.58
0.45
0.49
0.47
0.5
2.71
0.75
0.58
0.55
0.52
0.52
0.75
0.49
0.78
0.57
0.57
0.46
0.51
3.47
0.5
1.19
0.74
0.57
0.55
0.98
10.84*
0.51
G-123
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/01/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
Influent (NTU)
121.89
123.94
112
115.24*
111.8
116.98
125.61 *
120.96
113.06
111.32
114.92
125.44
122.48
115.86
79.01
58.11
106.37
112.25
111.73
115.87
118.65
121.31
124.09
124.14
Effluent (NTU)
0.48
0.74
0.54
0.58
0.46
6.9
10.9*
0.51
0.81
0.66
0.58
0.55
0.54
10.78 *
0.53
0.52
0.9
0.79
0.6
0.48
0.55
0.5
0.56
5.98
0.86
0.62
0.58
0.55
2.74
1.51
0.64
0.64
0.64
0.7
1.24
0.88
1.41
1.09
0.99
0.7
0.87
0.74
1.06
6.75
1.37
0.94
0.91
G-124
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
Influent (NTU)
124.06
125.96
124.35
124.47
127.77
129.18
127.85
126.83
126.89
124.58
123.4
124.71
127.32
124.38
123.34
124.11 *
124.34
125.77
137.95 *
169.4 *
195.9
203.59*
209.22 *
Effluent (NTU)
0.87
0.9
4.77
0.93
1.77
1.19
1.45
0.93
1.34
1.04
1.08
5.94
1.89
1.58
1.4
1.4
2.42
1.65
1.24
2.51
1.32
1.71
1.07
1.62
2.82
1.27
2.82
1.92
1.62
1.46
1.42
16.34*
1.39
1.27
2.3
1.3
1.97
1.15
15.6*
17.02 *
2.11
5.39
5.32
27.47 *
5.18
2.87
3.15
G-125
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/03/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
Influent (NTU)
201.44
183
167.8 *
149
122.39
107.76
98.2
97.12
97.67
87.09
88.53
40.78 *
51.45
78.05
76.21
73.64
77.47
78.82
79.01
86.97
90.29
88.8
88.96
Effluent (NTU)
18.41 *
1.38
0.75
0.68
1.04
12.66 *
0.64
0.73
1.64
0.58
0.57
0.82
0.45
0.47
0.66
0.4
0.47
0.48
0.37
0.57
0.45
0.74
0.5
5.72
12.51 *
0.69
0.67
0.92
1.1
1.28
1.62
1.74
1.7
1.92
1.79
1.61
1.76
1.6
1.48
1.53
1.31
1.12
1.19
1.03
0.96
1.07
0.97
G-126
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
Influent (NTU)
89.05
85.31
89.44
94.46
91
90.91
92.27
91.66
88.4
90.23
89.94
88.14
88.02
86.14
80.65
83.71
86.47
83.8
82.69
82.78
80.86
80.86
81.38
Effluent (NTU)
0.91
1.02
0.92
0.91
0.96
0.84
0.78
0.81
0.71
0.68
0.75
0.68
0.69
0.74
0.66
0.66
0.71
0.64
0.66
0.66
0.59
0.57
0.61
0.57
0.58
0.63
0.6
0.6
0.65
0.62
0.6
0.66
0.61
0.59
0.62
0.58
0.59
0.64
0.61
0.61
0.67
0.62
0.63
0.68
0.63
0.6
0.62
G-127
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/11/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
Influent (NTU)
85.92
79.08
79.66
82.85
77.88
33.32
52.53
63.07
69.43
69.88
75.94
81.78
73.61
78.83
83.6
79.59
79.17
82.54
77.85
77.94
82.59
79.9
80.4
81.81
76.89
Effluent (NTU)
0.68
0.55
0.63
0.62
0.6
2.96
0.44
0.45
1.01
0.46
0.42
0.44
0.46
0.47
0.43
0.48
0.43
0.43
0.47
0.43
0.42
0.45
0.42
0.42
0.44
0.44
0.43
0.43
0.42
0.43
0.43
0.42
0.42
0.43
0.43
0.45
0.46
0.47
0.46
0.45
0.45
0.45
0.43
0.44
0.45
G-128
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/12/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
Influent (NTU)
78.82
83.33
80.06
81.17
82.61
77.58
78.05
82.32
80.7
81.08
82.26
78.84
82.48
91.67
94.62
96.3
Effluent (NTU)
0.43
0.47
0.5
0.48
0.51
0.5
0.46
0.49
0.48
0.46
0.47
0.47
0.46
0.53
0.57
0.55
0.6
0.6
0.54
0.57
0.6
0.5
0.55
0.55
0.53
0.63
0.68
0.65
3.08
0.52
0.52
0.54
0.66
0.65
0.64
0.77
0.77
0.79
0.98
1.19
1.21
3.07
6.08
2.47
4.54
G-129
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
Influent (NTU)
Effluent (NTU)
6.41
0.98
0.96
0.78
0.63
0.67
0.62
0.49
0.51
1.79
0.45
0.43
0.49
0.4
1.13
0.54
0.5
2.43
0.66
7.17
0.57
0.48
0.48
0.55
6.27
0.73
0.93
2.02
1.32
4.52
1.1
0.84
4.12
0.64
2.21
1.24
1.91
1.3
2.06
3.71
6.53
1.84
5.72
1.15
1.25
3.44
2.83
G-130
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
Influent (NTU)
185*
173.75 *
165.38*
168.27*
176.92 *
179.8 *
165.36*
157.82
160.41
140.42
147.74
Effluent (NTU)
1.44
7.49
17.08 *
26.72 *
16.93 *
11.45 *
14.31 *
8.36
11.94*
19.16*
17.67 *
26.87 *
52.22 *
42.07 *
49.95 *
77.44 *
40.4*
30.08 *
38.68 *
22.98 *
27.27 *
52.11 *
39.61 *
53.18*
93.66 *
64.68 *
36.8*
51.97*
23.12*
19.57*
32.39 *
22.04 *
34.62 *
10.51 *
39.2*
32.35 *
45.5*
33.49 *
2.32
2.36
1.82
2.42
3.33
1.48
2.37
1.31
1.32
G-131
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/16/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
Influent (NTU)
148.79
133.56
142.5
147.17
148.08
146.78
147.24
152.5
147.95 *
144.34
150.51 *
95.89
109.48
133.33*
130.57
125.31
120.41
117.5
117.42
117.91
116.66
116.16
116.26
117.31
Effluent (NTU)
1.56
4.58
2.8
3.31
5.56
9.08
1.68
3.74
4.36
5.32
4.65
5.87
6.06
9.13
1.93
4.84
6.29
14.82 *
11.84*
11.84*
23.69 *
11.86*
2.48
1.98
2.85
10.73 *
6.91
1.48
3.69
5.69
2.69
2.45
1.31
2.6
1.19
1.61
2.76
0.98
9.12
1.27
0.86
1.27
0.89
1.23
1.07
1.12
G-132
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
Influent (NTU)
117.39
116.67
117.81
117.77
118.15
118.01
119.5
119.74
121.63
119.09
108.09
108.14
107.91
107.69
109.34
108.73
108.36
108.29
109.53
109.41
109.59
110.66
113.89
Effluent (NTU)
1.3
1.16
4.89
1.29
0.94
1.26
2
1.03
1.64
0.96
1.62
1.61
0.82
1.17
0.88
6.11
0.9
1.58
0.8
0.89
0.62
0.84
0.65
0.84
1.05
0.69
0.99
0.67
0.95
0.78
1.18
0.87
0.86
2.74
0.92
0.72
0.78
1.1
0.75
0.84
0.99
2.05
1.18
1.04
1.12
1.43
1.05
G-133
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/18/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
Influent (NTU)
114.93
116.75
117.6
121.01
122.39
123.88
124.65
126.37
114.34
124.52
124.24
122
107.99
107.19
107.14
108.22
107.9
107
106.73
106.11
106.04
105.87
105.16
104.8
Effluent (NTU)
1.03
1.21
2.34
1.32
1.12
1.2
1.49
1.07
1.03
1.22
1.98
1.34
1.12
1.26
1.61
0.8
0.86
1.17
1.91
2.16
0.88
1.22
1.16
1.32
1.12
1.24
1.37
1.5
1.15
1.66
1.33
1.61
1.25
1.27
1.49
1.66
1.48
1.73
1.43
1.77
6.97
1.57
1.47
1.83
6.22
2.02
1.63
G-134
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
Influent (NTU)
104.66
105.15
104.83
104.75
104.64
104.54
104.61
104.92
105.08
105.65
105.53
106.06
103.03
102.6
102.08
101.72
101.75
102.01
101.66
101.39
101.29
101.55
101.73
Effluent (NTU)
1.89
6.79
1.67
1.69
1.98
2.72
2.15
1.47
5.02
6.51
1.76
1.72
2.14
2.22
2.33
1.91
2.09
6.69
1.86
1.85
2.21
2.36
2.39
1.97
2.16
6.37
1.96
1.92
2.25
2.24
2.41
2.03
2.22
3.25
2.05
2.05
2.31
2.19
2.49
2.09
2.27
3.46
2.15
2.15
1.99
2.24
2.63
G-135
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/19/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
Influent (NTU)
101.48
101.6
101.18
101.19
101.2
98.96
99.85
100.76
99.42
97.99
97.33
96.51
96.91
96.69
96.26 *
96.32
95.79
95.85
96.26
96.14
96.15
96.14
96.23
96.22
Effluent (NTU)
2.2
2.38
3.43
2.21
2.25
2.54
2.36
2.7
2.25
0.87
1.72
1.6
1.31
1.44
1.64
1.27
1.79
1.44
1.55
1.84
2.41
2.36
1.6
2.2
1.71
1.84
2.26
1.89
14.79 *
1.88
2.72
2.49
2.12
2.66
2.13
2.39
2.12
5.65
5.37
2.31
2.94
2.54
2.65
2.36
2.39
3.52
2.7
G-136
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
Date
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/20/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
Influent (NTU)
96.87
97.02 *
96.53
96.32
96.19
95.95
39.12
37.61
72.06
64.73
49.02
42.41
36.8
33.35
35.19
35.15
31.92
30.28
29.14
27.15
30.13
30.4
28.05
26.37
Effluent (NTU)
2.45
2.56
3.26
2.53
10.02 *
3.07
3.81
3.82
2.66
4.02
2.76
2.95
8.18
1.4
1.33
2.45
1.35
2
1.76
1.61
1.41
1.26
1.13
1.85
1.91
1.88
1.64
1.48
1.37
2.06
2.07
1.98
1.71
1.52
1.38
2.06
2.1
1.99
1.73
1.52
1.38
2.09
2.04
1.9
1.67
1.49
1.36
G-137
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
Date
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
04/26/2005
521/1
521/1
521/1
521/1
521/1
521/1
521/1
521/1
503/1
503/1
503/1
503/1
416/1
416/1
416/1
416/1
416/1
416/1
416/1
416/1
416/1
416/1
402/1
402/1
402/1
402/1
402/1
402/1
402/1
402/1
402/1
402/1
330/1
330/1
Influent (NTU)
26.82
24.51
25.67
28.3
26.65
25.32
120.4
131.4
131.4
163.7
293.9
14.6
51.2
7.9
24.3
20.8
8.2
0
126.1
72.2
62.3
47.2
58.6
102.3
33.2
22.6
24.9
4.7
238.8
78.9
89.7
47.9
44.8
53.3
55.9
61.4
23.5
4.9
95.2
52.7
Effluent (NTU)
1.99
1.96
1.87
1.61
1.45
1.33
1.93
1.93
1.81
1.55
1.41
1.27
1.9
0
0.6
0.6
0.4
0
0
0
0
1.6
1.7
2.6
0
0.9
1
1.1
0.9
0.8
0.9
0.6
0.6
0
0
1.2
0.7
0.5
0.5
0.7
0.4
0.6
0.6
0.4
0
0.7
0.8
G-138
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
Date
330/1
330/1
330/1
330/1
330/1
330/1
330/1
330/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
327/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
324/1
Influent (NTU)
53
74.8
51.9
28.7
8.5
7.5
9.9
120.4
80.9
61.3
51.5
69.2
88.9
53.3
54.6
56.6
67.6
84.1
22.8
17.9
0
0
39
41.2
88
113.4
132.8
50.7
68.7
45.3
73.1
78.5
90.9
55.2
75.1
73.5
87.2
95.6
91.4
83.4
75.1
71.9
73.4
79.3
83.7
81.8
55.4
Effluent (NTU)
0.7
0.5
0.7
0.4
0.3
0.6
0.4
1.4
0.4
0.5
0.7
0.3
0.4
0.6
0.4
0.6
0.4
0.9
0.5
0.5
0
0
0.2
0.5
0.4
0.3
0.6
0.3
0.8
0.3
0.8
0.2
0.6
0.3
0.8
0.5
0.9
0.6
0.7
0.6
0
1
0.4
1.2
0.8
0.5
0.7
G-139
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
Date
324/1
322/1
322/1
322/1
322/1
322/1
322/1
322/1
322/1
322/1
322/1
322/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
320/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
312/1
Influent (NTU)
9.3
64.8
39.9
41.5
54.9
48.8
35.9
40
52.4
28.8
27.7
22.3
63
75.7
56
57.7
63
146.9
108
96.1
58.6
60.6
63.7
90.3
139.1
65
50.9
7.8
13.2
50
60.2
59.2
65.2
53.3
51.8
49
49.5
49.8
56.6
95.6
53.4
50.5
50.7
50.5
60.2
71.9
42.9
Effluent (NTU)
0
0.7
0.5
0.6
1.1
1.7
0.4
0.4
1.3
0.5
0.8
3.4
0.3
0.7
0.7
0.4
0.7
0
1.9
0.8
0.7
0.4
0.7
0.4
1
0.3
0.4
0.6
0.3
0.7
0.6
0.3
0.4
0.3
0.3
0.7
0.5
0.3
0.4
1
0.3
0.4
0.7
0.5
0.5
0.7
0.4
G-140
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
Date
312/1
312/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
311/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
309/1
306/1
306/1
306/1
306/1
306/1
302/1
302/1
302/1
301/1
301/1
301/1
301/1
301/1
301/1
301/1
Influent (NTU)
0
0
57.7
55.8
66.1
81.8
70.7
54.5
60.4
58.5
68
102.1
61.5
47.9
62.6
63.7
66.4
33.5
28.2
31.1
85.1
85.5
69.3
72.8
81.9
55.6
44.4
47.7
30.2
18.8
18.7
0
7.4
6.8
14.2
16.3
11.4
33.9
18.5
35.1
65.6
65.7
52.4
50.2
48.9
61.8
57.8
Effluent (NTU)
0
0
0.6
0.4
0.4
0.2
0.6
0.2
0.5
0.2
0.3
1
0.3
0.3
0.5
0.5
0.6
0.2
0.6
0
0.2
0.6
0.4
0.3
0.6
0.4
0.4
0.5
0.2
0.5
0.5
0
0.2
0.5
0.2
0.4
2.3
0.2
2.1
4.2
0
0.7
0.1
0.2
0.8
0.5
0.2
G-141
-------
Appendix G: Turbidity Report Tables
Listing 1: Turbidity Measurements as Reported
Site/System
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
Date
301/1
301/1
301/1
301/1
301/1
301/1
301/1
301/1
226/1
226/1
226/1
226/1
226/1
226/1
226/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
224/1
03/31/1999
04/01/1999
04/02/1999
04/03/1999
04/06/1999
04/08/1999
04/13/1999
05/03/1999
06/08/1999
03/31/1999
04/01/1999
04/02/1999
04/03/1999
04/06/1999
04/08/1999
04/13/1999
05/03/1999
06/08/1999
Influent (NTU)
56.9
55
35.7
29.1
23.4
19.3
20.2
32.1
96.4
86.9
77.6
48.1
38.4
39.2
73.7
175.9
173.1
233.3
246.2
257.4
180.1
57.9
56.9
113.2
163.1
208.4
75.6
0
472
136.1
128.3
155.3
128
167.12
361
124.6
78.1
472
136.1
128.3
155.3
128
167.12
361
124.6
78.1
Effluent (NTU)
0.7
0.2
0.3
0.6
0.5
0.2
0.5
0
0.8
0.3
1.8
0.8
0.4
0.5
1.4
1.9
3.2
2.9
5.7
2.3
0.5
0.9
2.9
0
1
0.8
0.6
0
11.4
36.1
28.3
25.8
9.8
19.5
5.1
34.4
4.9
6.84
24.5
23.4
22.4
19.87
4.6
1
G-142
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
10/29/2004
11/01/2004
1 1/02/2004
1 1/03/2004
1 1/04/2004
1 1/05/2004
1 1/08/2004
1 1/09/2004
11/10/2004
11/11/2004
11/12/2004
11/17/2004
11/18/2004
11/19/2004
1 1/22/2004
1 1/23/2004
1 1/24/2004
12/02/2004
12/06/2004
12/07/2004
12/08/2004
12/09/2004
12/10/2004
12/13/2004
12/14/2004
12/15/2004
12/16/2004
12/17/2004
12/20/2004
12/21/2004
12/21-22/2004
12/22/2004
12/28/2004
12/29/2004
12/30/2004
12/31/2004
01/01/2005
01/02/2005
01/02-03/2005
01/03/2005
01/03-04/2005
01/04/2005
01/04-05/2005
Daily Value
(Arithmetic
Average)
3.98
2.74
1.30
2.82
8.84
15.78
13.21
13.04
11.83
9.99
0.49
6.62
6.63
5.19
4.88
4.33
4.64
1.26
1.91
0.42
0.40
0.90
0.55
0.36
0.47
1.96
0.83
0.60
0.49
1.04
2.63
4.02
6.95
9.31
1.22
1.14
1.40
1.91
1.93
2.37
2.05
2.14
1.94
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
5
6
7
5
5
5
6
5
9
4
2
8
12
12
9
12
7
6
9
9
13
12
8
7
8
8
8
9
8
9
6
2
9
9
12
18
11
11
6
10
8
9
7
Standard
Deviation
2.62
3.29
0.35
3.79
3.37
4.07
9.38
3.03
4.09
3.47
0.01
2.29
0.83
0.66
0.39
0.41
0.50
0.92
2.03
0.11
0.27
1.19
0.46
0.08
0.18
2.45
0.65
0.26
0.10
1.58
0.45
4.85
6.86
10.03
0.57
0.52
0.81
0.77
0.63
0.63
0.52
1.00
0.89
Minimum
1.09
0.95
0.96
0.96
3.62
11.1
3.38
9.2
4.68
4.95
0.48
1.08
4.67
4.3
4.29
3.73
4.13
0.42
0.37
0.31
0.2
0.29
0.23
0.24
0.27
0.45
0.37
0.4
0.38
0.23
2.17
0.59
0.76
0.59
0.47
0.5
0.87
0.97
.25
.67
.24
.35
.23
Maximum
7.8
9.4
1.92
9.6
12.6
20.1
26.4
16.2
16.8
12.9
0.5
8
8.02
6.7
5.42
5.24
5.36
2.84
5.09
0.61
0.99
4.6
1.55
0.48
0.77
7.92
2.13
1.26
0.67
5.13
3.27
7.45
15.4
20.4
2.19
2.65
3.73
3.77
2.71
3.48
2.86
4.55
3.55
G-143
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
01/05/2005
01/06/2005
01/06-07/2005
01/07/2005
01/07-08/2005
01/08-09/2005
01/09/2005
01/09-10/2005
01/10-11/2005
01/11/2005
01/11-12/2005
01/12/2005
01/12-13/2005
01/13/2005
01/13-14/2005
01/14/2005
01/15/2005
01/15-16/2005
01/16/2005
01/16-17/2005
01/17/2005
01/18/2005
01/18-19/2005
01/19/2005
01/19-20/2005
01/20/2005
01/20-21/2005
01/21/2005
01/22/2005
01/23/2005
01/23-24/2005
01/24/2005
01/24-25/2005
01/25/2005
01/25-26/2005
01/26/2005
01/27/2005
01/28/2005
01/29/2005
01/29-30/2005
01/30/2005
01/30-31/2005
01/31/2005
02/02/2005
Daily Value
(Arithmetic
Average)
5.00
1.50
1.55
2.40
6.54
4.10
4.26
3.00
5.52
3.20
2.34
3.55
2.78
4.59
7.37
5.44
9.63
5.67
1.31
0.92
1.73
3.29
2.72
4.64
3.77
2.69
3.89
2.53
1.79
1.12
0.96
1.43
1.70
3.36
2.27
2.34
3.55
2.44
2.86
2.51
3.39
3.75
0.65
1.92
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
15
12
6
5
3
12
9
11
10
11
12
10
12
3
6
5
4
12
12
7
2
11
4
7
12
6
11
18
11
11
6
8
7
9
6
9
3
10
5
6
6
8
7
15
Standard
Deviation
6.09
0.48
0.44
0.92
2.06
0.75
0.54
0.54
2.62
2.37
0.66
0.90
0.37
0.43
4.22
4.00
5.84
3.14
0.56
0.31
0.85
1.62
0.59
1.15
1.80
0.86
2.05
1.12
0.58
0.24
0.22
0.45
0.43
1.25
0.54
1.01
0.10
0.61
1.42
0.56
1.54
2.21
0.10
0.94
Minimum
1.55
0.71
0.89
1.56
5.25
2.75
3.3
2.14
2.23
1.19
0.87
2.32
2.12
4.1
2.61
1.9
4.16
1.54
0.57
0.52
1.13
1.7
2.17
3.28
.69
.71
.65
.11
.13
0.83
0.77
0.84
1.21
1.58
1.39
1.38
3.49
1.65
0.4
1.91
1.86
2.36
0.51
0.92
Maximum
25.8
2.57
2.01
3.89
8.92
5.25
4.9
3.85
9.36
7.52
3.06
4.52
3.27
4.91
13.8
11.9
17.8
12.1
2.31
1.45
2.33
6.78
3.54
6.65
7.22
4.03
7.6
4.7
3.06
1.59
1.35
2.05
2.24
4.76
3.02
4.55
3.66
3.33
3.72
3.54
5.06
9.09
0.78
4.11
G-144
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Date
02/03-04/2005
02/07/2005
02/08/2005
02/09/2005
02/10/2005
02/11/2005
02/14/2005
02/17/2005
02/18/2005
02/19/2005
02/22/2005
02/23/2005
02/24/2005
02/25/2005
02/26/2005
02/27/2005
02/28/2005
03/01/2005
03/02/2005
03/03/2005
03/04/2005
03/06/2005
03/07/2005
03/08/2005
03/09/2005
03/10/2005
03/11/2005
03/14/2005
03/15/2005
03/16/2005
03/17/2005
03/18/2005
03/21/2005
03/22/2005
03/23/2005
03/24/2005
03/25/2005
03/26/2005
03/28/2005
03/29/2005
03/30/2005
03/30-31/2005
03/31/2005
12/22-23/2005
Daily Value
(Arithmetic
Average)
2.56
2.62
1.87
1.51
1.51
1.35
1.61
1.12
0.90
0.62
0.79
0.81
1.91
1.83
0.54
0.41
0.77
0.46
1.39
1.62
2.29
4.43
1.15
0.69
0.91
0.56
0.47
0.45
0.58
0.66
0.67
0.62
0.46
0.35
2.53
0.78
0.50
0.93
1.75
1.52
0.95
1.68
1.51
1.13
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
8
6
6
7
7
7
2
4
3
2
6
3
3
5
4
6
8
9
5
7
4
6
8
8
4
9
9
9
9
8
8
3
6
12
18
9
18
5
12
24
11
12
10
8
Standard
Deviation
2.50
1.45
0.42
0.21
0.27
0.49
0.26
0.24
0.27
0.16
0.22
0.44
1.28
0.74
0.12
0.08
0.52
0.13
0.88
0.17
0.38
1.26
0.36
0.20
0.53
0.17
0.08
0.10
0.13
0.08
0.18
0.51
0.20
0.12
2.20
0.14
0.16
0.04
0.40
0.87
0.26
0.40
0.25
0.22
Minimum
0.75
1.22
1.35
1.24
1.22
0.69
1.42
0.9
0.74
0.51
0.47
0.48
1.09
1
0.4
0.33
0.35
0.33
0.74
1.26
1.75
2.53
0.52
0.45
0.57
0.38
0.35
0.33
0.32
0.55
0.42
0.26
0.29
0.22
0.35
0.62
0.3
0.87
1.14
0.51
0.54
1.24
1.14
0.85
Maximum
8.1
5.4
2.44
1.9
1.87
2.17
.79
.37
.21
0.73
.05
.31
3.38
2.97
0.68
0.52
1.95
0.78
2.89
1.78
2.56
5.77
1.48
1.04
1.7
0.88
0.62
0.62
0.78
0.8
0.89
1.21
0.82
0.63
5
1.07
0.75
0.98
2.36
4.13
1.4
2.39
1.86
1.52
G-145
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS1
4 SYS2
4 SYS2
4 SYS2
4 SYS2
Date
12/31/2004
01/01/2005
01/03/2005
01/04/2005
01/05/2005
01/11/2005
01/12/2005
01/25/2005
02/07/2005
02/10/2005
02/11/2005
02/14/2005
02/23/2005
02/24/2005
03/01/2005
03/03/2005
03/04/2005
03/07/2005
03/24/2005
03/25/2005
04/12/2005
01/09/2005
01/10/2005
01/12/2005
01/13/2005
01/14/2005
01/15/2005
01/16/2005
01/17/2005
01/18/2005
01/19/2005
01/24/2005
01/25/2005
01/31/2005
02/01/2005
02/08/2005
02/24/2005
03/03/2005
03/04/2005
03/05/2005
01/09/2005
01/10/2005
01/12/2005
01/13/2005
Daily Value
(Arithmetic
Average)
1.00
1.00
1.22
1.10
0.62
2.05
0.98
1.75
2.23
7.63
7.18
1.69
0.80
0.74
0.87
0.54
0.53
0.45
2.11
0.66
1.59
9.12
0.87
0.08
0.53
0.73
0.36
0.31
0.81
0.67
0.31
5.54
1.18
3.98
2.46
23.00
1.22
0.77
0.59
0.71
5.35
2.16
1.23
1.54
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
1
1
9
2
9
6
5
2
3
7
8
7
3
5
4
8
2
2
2
13
3
6
3
1
5
3
3
6
3
8
8
5
2
5
4
1
6
6
4
8
5
5
1
5
Standard
Deviation
0.59
0.71
0.23
2.14
0.87
0.64
0.83
8.97
5.08
0.48
0.32
0.18
0.23
0.18
0.03
0.09
0.04
0.33
0.31
8.72
0.38
0.28
0.30
0.03
0.15
0.63
0.28
0.19
6.71
0.04
3.36
1.95
0.45
0.22
0.21
0.22
6.47
1.61
0.95
Minimum
1
1
0.04
0.6
0.4
0.2
0.3
1.3
1.3
1.2
3
1.11
0.43
0.48
0.72
0.31
0.51
0.38
2.08
0.22
1.3
2.19
0.57
0.08
0.34
0.52
0.34
0.12
0.26
0.34
0.14
0.8
1.15
0.86
1.09
23
0.65
0.6
0.46
0.47
1.07
0.79
1.23
0.41
Maximum
1
1
2
1.6
1.1
5.5
2.4
2.2
2.9
26
15.3
2.47
1.04
0.94
1.21
0.81
0.55
0.51
2.14
1.12
1.91
22.4
1.3
0.08
1.01
1.07
0.39
0.58
1.5
1.26
0.68
16.9
1.2
8.57
5.23
23
1.87
1.21
0.91
1.07
16.6
4.63
1.23
3.03
G-146
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
4 SYS2
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
8
8
8
8
8
8
8
8
8
8
8
Date
01/15/2005
01/16/2005
01/17/2005
01/18/2005
01/19/2005
01/24/2005
01/25/2005
01/31/2005
02/01/2005
02/08/2005
02/09/2005
02/23/2005
03/03/2005
03/04/2005
03/05/2005
11/8-11/12
11/14-11/16
12/29/2004
12/30/2004
01/01/2005
01/02/2005
02/18/2005
02/22/2005
02/23/2005
02/25/2005
02/28/2005
03/02/2005
03/03/2005
03/04/2005
03/07/2005
03/22/2005
03/23/2005
11/13/2005
12/20/2004
01/02/2005
01/03/2005
01/04/2005
01/05/2005
01/06/2005
01/07/2005
01/08/2005
01/09/2005
01/10/2005
01/11/2005
Daily Value
(Arithmetic
Average)
0.66
0.70
0.90
1.52
0.46
10.78
1.17
7.03
4.27
33.20
0.91
2.31
0.80
1.09
0.51
5.85
3.30
1.43
0.58
32.25
4.24
0.38
0.69
0.80
2.19
1.97
1.76
1.96
2.51
2.39
3.70
2.74
3.24
0.57
0.52
0.82
2.96
6.31
12.51
22.19
10.62
8.40
7.34
20.95
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
4
4
3
8
7
5
5
5
4
1
1
5
7
5
2
6
2
4
4
5
4
4
4
3
3
3
4
3
3
1
1
2
10
3
5
2
5
9
11
7
8
7
8
10
Standard
Deviation
0.32
0.73
0.28
2.33
0.42
16.67
0.55
6.82
3.94
3.42
0.37
0.37
0.28
1.38
0.85
0.17
0.26
16.91
1.79
0.09
0.12
0.09
0.56
0.84
0.42
0.91
0.34
0.01
3.88
0.31
0.11
0.05
2.97
4.15
6.87
10.84
3.31
1.13
4.05
14.66
Minimum
0.45
0.23
0.64
0.41
0.17
0.45
0.62
1.6
1.2
33.2
0.91
0.66
0.54
0.73
0.31
3.8
2.7
1.19
0.34
6.03
2.03
0.26
0.54
0.7
1.54
1.06
1.39
1.23
2.27
2.39
3.7
2.73
0.1
0.38
0.42
0.78
0.92
1.95
3.89
8.2
5.92
6.46
2.32
3.16
Maximum
1.14
1.78
1.2
7.25
1.39
40
1.96
18.8
9.83
33.2
0.91
8.42
1.61
1.64
0.7
7.1
3.9
1.55
0.95
46.5
6.39
0.45
0.83
0.86
2.53
2.7
2.29
2.98
2.9
2.39
3.7
2.74
13
0.93
0.69
0.85
8.12
13.2
23.7
37.5
16
9.86
14.1
43.1
G-147
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
8
8
8
8
8
8
8
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Date
01/12/2005
01/13/2005
01/14/2005
01/15/2005
01/16/2005
01/17/2005
03/07/2005
12/29/2004
12/30/2004
12/31/2004
01/01/2005
01/02/2005
01/03/2005
01/04/2005
01/05/2005
01/06/2005
01/07/2005
01/08/2005
01/09/2005
01/10/2005
01/11/2005
01/12/2005
01/13/2005
01/14/2005
01/17/2005
01/18/2005
01/19/2005
01/20/2005
01/21/2005
01/22/2005
01/23/2005
01/24/2005
01/25/2005
01/28/2005
01/31/2005
02/01/2005
02/02/2005
02/16/2005
02/17/2005
02/18/2005
02/19/2005
02/20/2005
02/21/2005
03/03/2005
Daily Value
(Arithmetic
Average)
35.90
32.29
38.75
14.17
3.92
1.73
0.40
2.80
3.17
14.06
15.12
1.16
10.05
23.21
1.13
1.23
2.65
6.73
3.04
2.15
7.66
1.81
4.73
1.27
6.11
3.53
2.35
1.52
2.83
0.96
1.00
1.65
2.59
4.73
3.61
2.14
1.89
4.79
5.75
0.55
0.55
1.38
0.72
1.13
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
3
5
2
3
6
4
1
10
12
18
12
16
6
10
3
11
10
23
14
13
17
28
18
21
7
5
7
4
4
7
1
6
3
3
6
7
6
3
5
22
10
11
12
1
Standard
Deviation
31.56
18.91
2.62
8.93
3.58
0.09
2.65
3.48
10.41
9.92
0.67
4.84
9.91
0.18
0.53
2.51
6.57
2.58
2.00
12.93
2.04
8.47
0.53
8.10
3.97
1.13
0.58
1.32
0.51
0.28
0.45
1.39
1.51
0.96
0.72
2.47
10.94
0.22
0.31
0.39
0.12
Minimum
11.7
7.55
36.9
7.91
0.37
1.63
0.4
0.33
0.94
1.12
1.54
0.45
4.15
4.21
0.97
0.73
1.18
0.6
0.78
0.51
0.42
0.43
0.31
0.38
0.63
0.49
1.41
1.03
1.52
0.21
1
1.27
2.1
3.12
2.14
1.32
0.98
2.96
0.39
0.34
0.37
0.91
0.56
1.13
Maximum
71.6
54.3
40.6
24.4
9.36
1.81
0.4
7.76
13.1
32.1
26.7
2.47
15
33.6
1.33
2.14
9.26
20.5
9.48
7.5
38.7
9.99
29.6
2.69
20.1
10.1
4.62
2.24
3.97
1.66
1
2.1
3
5.56
5.28
3.54
2.59
7.6
25.3
1.43
1.22
1.93
0.91
1.13
G-148
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
11
11
11
11
11
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BHRBP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BWWTP
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
BZR08
Date
03/04/2005
03/05/2005
03/07/2005
03/08/2005
03/09/2005
419/1
406/1
330/1
326/1
323/1
321/1
315/1
309/1
306/1
227/1
220/1
216/1
215/1
208/1
206/1
202/1
118/1
117/1
109/1
108/1
106/1
104/1
103/1
01/06/2007
01/08/2007
01/09/2007
02/09/2007
03/02/2007
03/21/2007
05/11/2007
05/14/2007
01/15/2008
01/16/2008
01/17/2008
01/18/2008
01/21/2008
01/28/2008
01/29/2008
01/30/2008
Daily Value
(Arithmetic
Average)
0.87
0.83
1.33
0.96
1.55
3.98
6.28
3.14
1.76
1.02
0.72
1.50
1.36
0.75
2.15
2.16
0.33
0.61
1.66
0.49
1.18
0.76
0.67
1.13
0.53
0.59
0.48
1.69
1.81
2.32
1.75
1.47
0.9
2.07
2.11
3.97
2.21
1.35
0.92
0.97
1.80
0.95
1.46
0.57
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
9
6
8
8
7
9
15
20
17
15
17
13
19
11
15
8
15
15
17
9
17
23
20
15
29
20
28
41
28
21
24
3
1
9
8
3
1
5
3
7
1
2
7
7
Standard
Deviation
0.09
0.19
0.46
0.21
0.92
2.54
0.67
0.96
0.71
0.47
0.47
1.50
0.62
0.33
1.29
2.24
0.15
0.39
1.47
0.21
0.63
0.89
0.51
1.02
0.50
0.50
0.48
1.59
0.22
0.34
0.22
0.35
0.8
0.67
2.22
0.55
0.49
0.63
0.64
2.23
0.44
Minimum
0.75
0.63
0.83
0.71
0.85
0.8
4.3
1
0.7
0.4
0.4
0.4
0.9
0.4
0.4
0.3
0.2
0.3
0.5
0.3
0.3
0.2
0.3
0.4
0.2
0.2
0.2
0.2
1.4
1.2
1.2
1.1
0.9
0.6
1.5
1.6
2.21
0.64
0.52
0.56
1.8
0.49
0.38
0.21
Maximum
1.02
1.15
2.01
1.27
3.12
9.2
6.9
4
3.3
2.1
1.9
6.3
3
1.6
4.3
7.2
0.8
1.5
5.4
0.9
2.6
4.1
2
4.2
2.4
1.8
2.1
7.3
2.2
3
2.2
1.8
0.9
2.9
3
6
2.21
2.03
1.47
2.34
1.8
1.4
6.5
1.4
G-149
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
BZR08
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
ELLRD
HEO
HEO
HEO
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
02/04/2008
05/03/2005
05/04/2005
05/05/2005
05/09/2005
05/11/2005
05/12/2005
05/13/2005
05/16/2005
05/18/2005
05/20/2005
05/21/2005
05/22/2005
05/23/2005
05/24/2005
05/25/2005
05/26/2005
05/27/2005
05/30/2005
05/31/2005
01/14/2000
02/02/2000
02/09/2000
03/10/2003
03/11/2003
03/12/2003
03/13/2003
03/17/2003
03/21/2003
03/24/2003
03/31/2003
04/02/2003
04/04/2003
04/09/2003
04/10/2003
11/18/2003
1 1/29/2003
12/01/2003
12/02/2003
12/03/2003
12/04/2003
12/05/2003
12/06/2003
12/09/2003
Daily Value
(Arithmetic
Average)
1.10
3.91
5.23
3.93
1.78
2.95
3.24
4.1
4.83
2.97
3.24
2.87
4
3.95
1.95
2.31
2.5
4.4
4.14
1.76
25.20
25.00
13.95
1.16
2.42
2.64
3.33
1.60
2.02
1.70
1.42
1.93
1.24
1.19
1.41
4.82
4.67
4.16
2.62
2.06
2.22
2.63
2.93
2.94
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
5
82
84
84
55
65
122
80
64
139
154
71
51
185
158
116
68
11
54
88
1
1
1
12
12
12
12
9
9
9
9
6
6
6
6
9
17
18
9
12
31
19
22
8
Standard
Deviation
0.58
.47
.62
.22
.48
.36
1.1
1.83
2.54
2.7
2.62
3.08
2.52
2.45
2.1
2.1
2.11
3.63
3.64
2.22
0.13
0.38
0.96
0.37
0.53
0.60
0.88
0.30
0.22
0.23
0.34
0.42
0.30
0.26
0.40
1.20
0.70
0.55
0.47
0.46
0.97
Minimum
0.67
1.25
1.32
1.32
0.37
0.81
1.17
1.23
0.9
0.13
0.34
0.21
0.26
0.3
0.26
0.32
0.34
0.38
0.2
0.16
25.2
25
13.95
0.98
1.9
0.86
2.77
0.98
1.26
0.79
0.87
1.6
0.88
0.77
0.89
4.17
4.17
3.52
1.34
1
1.39
1.92
1.89
1.29
Maximum
2.1
9.61
8.83
6.66
4.72
9.26
8.66
9.79
9.73
9.88
9.66
9.92
9.83
9.88
9.99
8.31
8.73
8.84
9.97
8.27
25.2
25
13.95
1.4
3.2
4.05
4
2.31
2.91
3.31
1.82
2.14
1.5
1.75
2.02
5.18
4.97
4.83
4.66
3.17
3.68
3.52
3.62
4.68
G-150
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
Date
12/10/2003
12/11/2003
12/15/2003
12/16/2003
12/17/2003
12/22/2003
12/23/2003
12/24/2003
12/26/2003
12/29/2003
12/30/2003
01/02/2004
01/05/2004
01/06/2004
01/08/2004
01/09/2004
01/12/2004
01/13/2004
01/14/2004
01/15/2004
01/16/2004
01/19/2004
01/20/2004
01/21/2004
01/22/2004
01/23/2004
01/26/2004
01/27/2004
01/28/2004
01/29/2004
01/30/2004
01/31/2004
02/02/2004
02/03/2004
02/04/2004
02/05/2004
02/06/2004
02/07/2004
02/1 1/2004
02/12/2004
02/16/2004
02/17/2004
02/18/2004
02/19/2004
Daily Value
(Arithmetic
Average)
3.55
3.20
3.08
2.05
2.08
3.90
3.17
3.09
2.96
2.09
2.46
2.71
3.64
2.92
3.77
3.34
3.67
3.76
3.49
3.92
3.46
3.96
3.57
3.20
3.59
3.64
3.94
3.42
3.57
3.78
3.71
3.67
2.92
2.89
3.16
3.10
3.08
3.26
3.01
2.94
3.08
3.28
3.73
2.78
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
6
8
5
5
5
5
4
6
7
6
7
8
6
7
13
7
9
7
13
8
12
10
10
10
10
14
13
11
14
18
19
7
7
8
8
8
8
7
8
7
8
8
7
6
Standard
Deviation
0.71
1.12
1.08
1.10
0.28
0.64
0.31
1.00
0.56
0.26
0.63
0.92
0.52
0.46
0.75
0.30
0.63
0.60
0.52
0.57
0.62
0.55
0.60
0.32
0.51
0.45
0.55
0.69
0.58
0.79
0.42
0.46
0.47
0.81
0.57
1.04
0.38
0.32
0.82
1.22
0.31
0.83
0.67
0.39
Minimum
2.73
1.23
1.58
0.76
1.83
3.19
2.88
2.07
2.14
1.68
1.81
1.69
2.87
2.16
2.53
2.98
2.43
2.68
2.81
2.66
2.62
2.98
2.98
2.62
2.89
2.63
3.04
2.7
2.8
1.99
2.69
3.11
2.42
1.79
2.37
1.28
2.65
2.67
1.37
1.28
2.64
2.12
2.92
2.18
Maximum
4.62
4.62
4.32
3.62
2.53
4.92
3.61
4.45
3.61
2.37
3.66
4.06
4.17
3.62
4.83
3.92
4.41
4.67
4.51
4.5
4.74
4.91
4.63
3.72
4.39
4.28
4.85
4.97
4.43
4.82
4.71
4.32
3.61
3.92
4.07
4.56
3.62
3.67
4.19
4.21
3.48
4.68
4.56
3.19
G-151
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
LSIDE
SC05
SC05
SC05
SC05
SC05
SC05
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SC08
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
SEAAIR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
Date
02/23/2004
02/25/2004
02/27/2004
03/01/2004
03/02/2004
03/03/2004
03/04/2004
03/05/2004
03/08/2004
03/09/2004
03/23/2005
03/24/2005
03/25/2005
03/26/2005
03/28/2005
03/29/2005
02/07/2008
02/11/2008
02/12/2008
02/13/2008
02/14/2008
02/15/2008
02/16/2008
02/17/2008
02/18/2008
02/19/2008
02/20/2008
02/23/2008
02/24/2008
04/01/2005
04/11/2005
04/12/2005
04/16/2005
04/18/2005
04/19/2005
04/20/2005
04/26/2005
04/03/2005
521/1
503/1
416/1
402/1
330/1
327/1
Daily Value
(Arithmetic
Average)
2.68
3.29
3.56
3.08
3.53
3.46
3.52
3.59
2.31
2.57
0.30
0.50
0.50
0.30
0.61
0.32
3.34
0.71
0.85
0.69
2.11
1.08
1.32
0.89
1.09
1.34
1.36
0.65
0.88
1.89
0.93
0.52
2.51
1.63
2.28
2.45
1.83
1.55
0.53
1.97
0.85
0.62
0.65
0.52
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
8
8
9
9
8
7
8
8
8
8
7
10
7
1
4
1
8
10
12
12
12
11
8
11
7
5
4
12
12
163
75
68
93
85
88
48
48
83
3
3
8
9
10
12
Standard
Deviation
0.48
0.30
0.42
0.36
0.47
0.53
0.67
0.52
0.82
0.41
0.16
0.50
0.25
0.30
2.36
0.33
1.74
0.71
0.94
0.81
1.51
0.52
0.67
1.38
1.05
0.37
0.68
2.19
0.67
0.31
2.25
1.41
1.32
0.94
0.98
1.30
0.12
0.55
0.18
0.24
0.31
0.16
Minimum
2.04
2.91
3.16
2.38
2.87
2.82
2.75
2.72
1.22
2.17
0.15
0.03
0.24
0.3
0.33
0.32
0.79
0.44
0.16
0.033
0.47
0.31
0.25
0.33
0.65
0.27
0.47
0.3
0.34
0.44
0.55
0.42
0.4
0.62
0.8
0.87
1.13
0.37
0.4
1.6
0.6
0.4
0.3
0.3
Maximum
3.43
3.84
4.46
3.47
4.14
4.47
4.69
4.19
3.49
3.42
0.62
1.85
0.92
0.3
1.03
0.32
7.3
1.42
6.29
2.68
3.54
3.09
4.86
1.74
2.54
3.73
2.49
1.42
2.5
9.49
5.72
2.96
9.13
9.12
6.97
5.65
8.18
6.75
0.6
2.6
1.1
1.2
1.4
0.9
G-152
-------
Appendix G: Turbidity Report Tables
Listing 2: Daily Values (NTU) for Turbidity
Site/
System
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
STCLLR
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS1
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
WLCPO SYS2
Date
324/1
322/1
320/1
312/1
311/1
309/1
306/1
302/1
301/1
226/1
224/1
03/31/1999
04/01/1999
04/02/1999
04/03/1999
04/06/1999
04/08/1999
04/13/1999
05/03/1999
06/08/1999
03/31/1999
04/02/1999
04/03/1999
04/06/1999
04/08/1999
04/13/1999
06/08/1999
Daily Value
(Arithmetic
Average)
0.58
1.04
0.64
0.50
0.44
0.42
0.72
2.17
0.42
0.86
2.06
11.40
36.10
28.30
25.80
9.80
19.50
5.10
34.40
4.90
6.84
24.50
23.40
22.40
19.87
4.60
1.00
Summary Statistics of Reported Measurements
Used to Calculate Daily Value
Number
24
11
16
18
17
11
5
3
13
7
11
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Standard
Deviation
0.26
0.89
0.39
0.20
0.21
0.14
0.89
2.00
0.24
0.55
1.57
Minimum
0.2
0.4
0.3
0.3
0.2
0.2
0.2
0.2
0.1
0.3
0.5
11.4
36.1
28.3
25.8
9.8
19.5
5.1
34.4
4.9
6.84
24.5
23.4
22.4
19.87
4.6
1
Maximum
1.2
3.4
1.9
1
1
0.6
2.3
4.2
0.8
1.8
5.7
11.4
36.1
28.3
25.8
9.8
19.5
5.1
34.4
4.9
6.84
24.5
23.4
22.4
19.87
4.6
1
G-153
-------
-------
Appendix H
Lognormal Distribution Used for Site-Specific, Long-Term Averages
and Variability Factors
-------
-------
Appendix H: Lognormal Distribution
INTRODUCTION
From its past experience with effluent data, the U.S. Environmental Protection Agency (EPA)
considers the lognormal distribution to be appropriate for statistically modeling daily values of
turbidity measurements to obtain the proposed limitations. This appendix describes EPA's use of
the lognormal distribution in estimating a long-term average and variability factor for each site-
specific data set described in Section 6. EPA then used the site-specific estimates to develop an
overall long-term average and variability factor for the limitations calculation, also as described in
Section 6.
The sections below describe the lognormal distribution and parameter estimates; long-term average
calculations; variability factor calculations; and an example based on data from site SC05. For the
final rule, EPA also intends to evaluate several other statistical approaches that are described in
Appendix I.
OVERVIEW OF THE LOGNORMAL DISTRIBUTION
The lognormal distribution is the most commonly used probability density model for environmental
contaminant data (Gilbert 1987). EPA's experience has shown that the daily pollutant
concentrations in effluent can be modeled by a lognormal distribution for a wide range of industrial
categories and pollutants. For example, histograms of daily pollutant concentration data associated
with effluent discharges frequently exhibit positive skewness (i.e., most values tending to occur at
the lower limit of the data range) and long tails to the right (i.e., gradually fewer values at the
higher end). Such histograms resemble the shape of the probability curve of a lognormal
distribution. Scientists have used the lognormal distribution to model environmental data, including
effluent data, primarily because it consistently provides a reasonably good fit to these data.
Figure H-l presents an example of a lognormal probability curve. Lognormal distributions assign
positive probability only to positive values, and pollutant concentrations cannot hold negative
values.
Figure H-l. An example lognormal probability curve.
If a random variable Xhas a lognormal distribution, its logarithm Y= log(JQ has a normal
distribution. The lognormal distribution and its properties and common applications are detailed in
Aitchison and Brown (1969) and in Crow and Shimizu (1988). If 7has a normal distribution with
expected value // and variance (?, the cumulative probability distribution function of X(i.e., the
probability that X can hold values less than or equal to some specified value x) takes the following
form:
H-l
-------
Appendix H: Lognormal Distribution
^^H-l
The expected value and variance of X are as follows:
-------
Appendix H: Lognormal Distribution
VARIABILITY FACTOR CALCULATIONS
A daily (i.e., one-day) variability factor (denoted as VFi) for a specified pollutant and site is
calculated as the ratio of the estimate of the 99th percentile, Pgg, of the distribution of X, to the
estimate of the expected value, E(X). Under the lognormal distribution
/*,
VFi = -g^T = e*p(// + 2,326; rr) = exp(2.326d- - 0.5a2)
E[X] exp(// + 0.5-cr ) FV
Under lognormal assumptions, the value of the daily variability factor VFt varies according to the
value of the standard deviation of the log-transformed measurements, a. Under these assumptions,
the smallest value that VFi can hold is 1, which occurs when a= 0. To determine the largest value
that VFi can hold, we differentiate the formula for VFi relative to o, set it equal to zero, and solve
for a.
dVF
1 = [exp(2.326o- - 0.5o"2)] [2.326 - 2(0.5o")] = 0
Note that this expression can equal zero only if the second component of this product equals zero.
This occurs when o= 2.326. Therefore, we substitute this value of o into the formula for VFi to
obtain its maximum value:
exp(2.326(2.326) - 0.5(2.326)2) = exp(0.5(2.326)2) = exp(2.705) = 14.96.
Thus, as the value of o increases from 0 to 2.326, the value of VF} increases from 1 to its
maximum of 14.96 under lognormal assumptions. At this point, VF} declines as o increases
beyond 2.326, approaching zero as o approaches infinity. Values close to 1 indicate a well-
controlled system. In contrast, a value near 15 would indicate a system with extreme variability in
its discharges.
H-3
-------
Appendix H: Lognormal Distribution
EXAMPLE
This section provides an example using data from Site SC05 shown in Table H-l. This section
applies the equations above to the data to show the calculations resulting in the site-specific long-
term average (LTA) of 0.43 nephelometric turbidity units (NTU) and the daily variability factor
(VFi) of 1.97.
Table H-l Turbidity Data from Site SC05
Date
3/23/2005
3/24/2005
3/25/2005
3/26/2005
3/28/2005
3/29/2005
Turbidity
(NTU)
0.304
0.504
0.500
0.300
0.610
0.320
log(turbidity)
-1.191
-0.685
-0.693
-1.204
-0.494
-1.139
= Q
|(-1.191-(-0.901))2 +(-0.685-(-0.901))2 +A +(-1.139-(-
I 6^1
LTA = exp(/} + O.So-2) = exp((-0.901 + (0.5 x 0.0976)) = 0.43
VFl = exp(2.326
-------
Appendix I
Alternative Statistical Methods
-------
-------
Appendix I: Alternative Statistical Methods
INTRODUCTION
Appendix H describes the lognormal distribution used to develop the proposed limitations for
turbidity in construction and development (C&D) stormwater runoff. The following sections
describe potential censoring in the data and additional statistical methods that the U.S.
Environmental Protection Agency (EPA) might consider for modeling data in developing the final
limitations. The section below provides a brief summary of the modified delta-lognormal
distribution that EPA has used in developing effluent limitations for other industries. The
remaining sections discuss the censored lognormal distribution, the probability regression method
for the lognormal distribution, and nonparametric methods.
Censoring
In statistical terms, measured concentrations are non-censored and non-detected values are left-
censored. The distinction between non-censored and left-censored measurements is often important
in statistically modeling the data. For the proposed rule, as explained in Section 6, EPA excluded
data values reported as zero nephelometric turbidity units (NTU). EPA then used the lognormal
distribution to model the remaining data values, which all had positive, non-censored, values. For
the final rule, EPA could reconsider its exclusion of zero values and consider them to be non-
detected instead. EPA also could receive and consider data sets with non-detected measurements
such as zero NTU or less than some value (e.g., < 0.10 NTU). In such situations, because the
lognormal distribution does not incorporate censoring directly, EPA would need to consider
applying other statistical methods that appropriately handle non-detected data. This appendix
presents other statistical methods that EPA might consider for the final rule.
Modified Delta-Lognormal Distribution
The modified delta-lognormal distribution models the data as a mixture of (1) detected
measurements that follow a lognormal distribution; and (2) non-detected measurements that occur
with a certain probability (Aitchison and Brown (1963), Kahn and Rubin (1989), and USEPA
(1993)). By a modification to the delta portion of the distribution, this model also allows for the
possibility that non-detected measurements can be observed at different sample-specific detection
limits.
For some industries, detected and non-detected measurements can be associated with different
pollutant-generating mechanisms. For example, non-detected measurements might indicate that the
pollutant is not generated by a particular source or production practice, and detected measurements
can be generated by different source, production, and/or wastewater treatment conditions. The
modified delta-lognormal distribution is appropriate for such data sets because each data type (i.e.,
detected measurements and non-detected measurements) is modeled separately with different
distributional properties.
If the modified delta-lognormal distribution appears to be appropriate for the C&D data, EPA also
will consider a further modification that would incorporate left-censoring into the lognormal
portion of the model while retaining the delta distribution for values reported as non-detected. This
model would explicitly censor the lognormal distribution at some point, such as the minimum
sample-specific detection limit observed in a data set. In doing so, this model would assume that
(1) the analytical method is incapable of quantifying measured concentrations of the pollutant
below that point in any sample; and (2) non-censored measurements can occur only above this
point. This modification is based on an extension of the method developed by Moulton and Halsey
(1995). EPA used a similar modification in developing the limitations for the pulp and paper
industry (USEPA 1993).
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Appendix I: Alternative Statistical Methods
Censored Lognormal Distribution
In some situations, it might not be reasonable to assume that detected and non-detected values are
associated with different pollutant-generating mechanisms. If so, techniques like a censored
lognormal distribution model might be appropriate. In a censored lognormal model (see Cohen
1959), all measurements, regardless of whether they are detected or non-detected, are regarded as
random measurements generated from a common underlying lognormal distribution. Estimates of
the mean, variance, and upper percentiles can be computed from the lognormal distribution that
best fits the available data. These estimates are similar to those derived under the modified delta-
lognormal model, except that in Cohen's procedure, non-detected measurements are treated merely
as left-censored data. Thus, it is assumed that non-detects, if the true concentration or mass
amounts were measurable, would follow the same lognormal pattern as the rest of the detected
data.
Probability Regression Method for the Lognormal Distribution
Like the censored lognormal distribution model, the probability regression method assumes that the
entire data set would follow a specific distributional model (e.g., the lognormal distribution) if
concentrations of non-detected measurements could be observed. The basic idea behind the
probability regression method can be described by first considering the case with no censored
measurements (for instance, a set of detected and precisely known observations). If these data
originate from an underlying lognormal distribution, a plot of the log-transformed measurements
versus ordered quantiles from a standard normal distribution would be expected to resemble a
linear pattern. In fact, it would be possible in this case to fit a linear regression to the points on the
probability plot and determine the slope and intercept of the fitted regression line. When non-
detected values are present, the probability regression method fits the regression line only to the
non-censored data. A parametric version of this approach estimates the mean and standard
deviation from the slope and intercept of this regression line.
To reduce the potential for introducing bias to the estimation process by fitting the regression line
to only non-censored values, EPA could consider a more robust version of this approach. Under
such a robust version, the method imputes numerical values for the non-detected measurements
according to where they would fall along the fitted regression line under a lognormal distribution.
Summary statistics (e.g., mean, percentiles) are then calculated from the combined set of detected
measurements and imputed values for the non-detects.
When the non-detected values do not all have the same detection limit and the set of detection
limits overlaps the set of detected measurements, the desired ordering of the data within the
probability regression method is more difficult to construct. However, Helsel and Cohn (1988)
have adapted the handling of data at a single detection limit to the more general case of multiple
detection limits and overlapping of non-censored and non-detected measurements. This adaptation
orders the data in terms of conditional probabilities. EPA will evaluate whether an ordering of the
non-detected values is appropriate for the C&D effluent data.
Nonparametric Methods
In contrast to the other statistical methods discussed in this appendix, nonparametric methods are
not based on fitting a specific distribution (e.g., lognormal) to the available data. Thus, the outcome
of nonparametric methods is not dependent on assumptions placed on the particular shape or form
of the true (unknown) distribution of the pollutant concentrations. For the final rule, EPA will
consider whether the following two nonparametric methods would be appropriate for modeling the
data.
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Appendix I: Alternative Statistical Methods
Kaplan-Meier (KM) Approach
The Kaplan-Meier (KM) approach is commonly used by the medical sciences to model survival
data but can easily be adapted to model data that are a mixture of non-censored and non-detected
values. KM is generally used to estimate the percentage of survival (or some other event) under
specified conditions as a function of time. Such situations have a mixture of non-censored and
right-censored data (i.e., measurements that are reported only as being above a specified lower
bound, such as surviving beyond some specified time). Survival data sets often include right-
censored values because, for example, the exact time to death might be unknown if a participant
withdraws early. For this reason, the KM approach was designed to effectively handle a mixture of
right-censored and non-censored data. The KM approach yields a nonparametric estimate of the
cumulative distribution function (CDF) of the underlying survival rates, conditioned on known
(non-censored) survival times.
Works such as Lawless (2003) and Helsel (2005) specify how the KM method can be extended to
left-censored data by using a flipping transformation. In such a transformation, left-censored values
are transformed to right-censored values. The transformation subtracts an arbitrarily determined
constant from the reported measurements and sample-specific detection limits. The constant value
is usually chosen to be a value that slightly exceeds the maximum observed detected measurement.
In this manner, instead of conditioning on known survival times, KM now can be used to condition
on measured (non-censored) concentrations above the smallest observed detection limit. The
estimated CDF gives the probability that a measurement falls below a specified value. As a result,
it allows distributional percentiles to be estimated, which are an important component of EPA's
approach to determining limitations.
Simple Estimation of Percentiles from the Observed Data
A simple nonparametric estimate of the 99th percentile of an effluent concentration data set is the
observed value that exceeds 99 percent of the observed data points. If a data set consists of fewer
than 100 observations, the best that can be done under this approach is to use the maximum value
as an approximate nonparametric estimate of the 99th percentile. However, this will underestimate
the true value (in statistical expectation). Because most of the data sets analyzed in support of
EPA's proposed limitations development had fewer than 100 observations, EPA would likely
consider other approaches to avoid underestimating the values used as a basis of the limitations.
References
Aitchison, J., and J.A.C. Brown. 1963. The LognormalDistribution. Cambridge University Press,
Cambridge, U.K.
Cohen, A.C., Jr. 1959. Simplified estimators for the normal distribution when samples are singly
censored or truncated. Technometrics 1:217-237.
Helsel, D.R. 2005. Nondetects and Data Analysis. Wiley & Sons, NJ.
Helsel. D.R., and T.A. Cohn. 1988. Estimation of descriptive statistics for multiply censored water
quality data. Water Resources Research 24(12): 1997-2004.
Kahn, H.D., and M.B. Rubin. 1989. Use of statistical methods in industrial water pollution control
regulations in the United States. Environmental Monitoring and Assessment 12:129-148.
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Appendix I: Alternative Statistical Methods
Lawless, J.F. 2003. Statistical Models and Methods for Lifetime Data. 2nd ed. Wiley & Sons, NJ.
Lee, L., and D. Helsel. 2005. Statistical analysis of water-quality data containing multiple detection
limits: S-language software for regression on order statistics. Computers & Geosciences
31:1241-1248.
Moulton, L.H., and N.A. Halsey. 1995. A mixture model with detection limits for regression
analysis of antibody response to vaccine. Biometrics 51:1197-1205.
USEPA (U.S. Environmental Protection Agency). 1993. Statistical Support Document
for Proposed Effluent Limitations Guidelines and Standards for the Pulp, Paper, and
PaperboardPoint Source Category. EPA 821-R-93-023. U.S. Environmental Protection
Agency, Washington, DC.
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