United States
Environmental Protection
Agency
Technical Development
Document for the Proposed
Section 316(b) Phase II Existing
Facilities Rule
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U.S. Environmental Protection Agency
Office of Water (4303T)
1200 Pennsylvania Avenue, NW
Washington, DC 20460
EPA-821-R-11-001
March 28, 2011
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Acknowledgements and Disclaimer
This document was prepared by Office of Water staff. The following contractors provided assistance in performing the
analyses supporting the conclusions detailed in this document.
TetraTech, Inc.
Office of Water staff have reviewed and approved this document for publication. Neither the United States Government
nor any of its employees, contractors, subcontractors, or their 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 document, or represents that its use by such a party would not infringe on
privately owned rights.
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Contents
Chapter 1: Background 1-1
1.0 Introduction 1-1
1.1 Purpose of Technical Development Document and Proposed Regulation 1-1
1.2 Background 1-2
Chapter 2: Summary of Data Collection Activities 2-1
2.0 Introduction 2-1
2.1 Primary Data Sourced from Previous 316(b) Rulemakings 2-1
2.1.1 Survey Questionnaires 2-1
2.1.2 Technology Efficacy Data 2-2
2.1.3 Existing Data Sources 2-2
2.1.4 Public Participation Activities 2-2
2.2 New Data Collected 2-3
2.2.1 Site Visits 2-3
2.2.2 Data Provided to EPA by Industrial, Trade, Consulting, Scientific or
Environmental Organizations or by the General Public 2-8
2.2.3 Updated Technology Database 2-10
2.2.4 Other Resources 2-11
2.2.5 Implementation Experience 2-15
2.2.6 New or Revised Analyses 2-18
Chapter 3: Scope/Applicability of Proposed Rule 3-1
3.0 Introduction 3-1
3.1 General Applicability 3-2
3.1.1 What is an "Existing Facility" for Purposes of the Section 316(b)
Existing Facility Rule? 3-3
3.1.2 What is "Cooling Water" and What is a "Cooling Water Intake
Structure?" 3-4
3.1.3 Would My Facility Be Covered if it is a Point Source Discharger? 3-5
3.1.4 Would My Facility Be Covered if it Withdraws Water From Waters of
the U.S.? What if My Facility Obtains Cooling Water from an
Independent Supplier? 3-6
3.1.5 What Intake Flow Thresholds Result in an Existing Facility Being
Subject to the Proposed Existing Facilities Rule? 3-7
3.1.6 Are Offshore Oil and Gas Facilities, Seafood Processing Vessels or
LNG Import Terminals Addressed Under the Proposed Existing
Facilities Rule? 3-9
3.1.7 What is a "New Unit" and How Are New Units Addressed Under This
Proposed Rule? 3-9
Chapter 4: Industry Description 4-1
4.0 Introduction 4-1
4.1 Industry Overview 4-2
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
4.1.1 Major Industry Sectors 4-2
4.1.2 Number of Facilities and Design Intake Flow Characteristics 4-3
4.1.3 Source Waterbodies 4-6
4.1.4 Cooling Water System Configurations 4-7
4.1.5 Design and Operation of Cooling Water Intake Structures 4-11
4.1.6 Existing Intake Technologies 4-14
4.1.7 Age of Facilities 4-14
4.1.8 Water Reduction Measures at Manufacturers 4-15
4.1.9 Land-based Liquefied Natural Gas Facilities 4-19
4.2 Electricity Industry 4-19
4.2.1 Domestic Production 4-20
4.2.2 Prime Movers 4-21
4.2.3 Steam Electric Generators 4-24
4.3 Manufacturers 4-25
4.3.1 Electric Generation at Manufacturers 4-25
4.4 Glossary 4-26
4.5 References 4-29
Chapter 5: Subcategorization 5-1
5.0 Introduction 5-1
5.1 Methodology and Factors Considered for Basis of Subcategorization 5-1
5.2 Age of the Equipment and Facilities 5-1
5.3 Processes Employed 5-2
5.3.1 Electric Generators 5-2
5.3.2 Manufacturers 5-5
5.4 Existing Intake Type 5-5
5.5 Application of Impingement and Entrainment Reduction Technologies 5-6
5.6 Geographic Location (including waterbody category) 5-6
5.7 Facility Size 5-7
5.7.1 Intake Flow 5-7
5.7.2 Generating Capacity 5-14
5.8 Non-Water Quality Environmental Impacts 5-15
5.9 Other Factors 5-15
5.9.1 Capacity Utilization 5-15
5.9.2 CUR Versus DIF 5-19
5.9.3 Low Capacity Utilization Compared With Spawning Seasonality 5-20
5.9.4 Fish Swim Speed 5-22
5.9.5 Water Use Efficiency 5-23
5.9.6 Land Availability 5-24
5.9.7 Other Factors 5-25
5.10 Conclusion 5-25
Chapter 6: Technologies and Control Measures 6-1
6.0 Introduction 6-1
6.1 Flow Reduction Technologies and Control Measures 6-2
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
6.2 Closed-Cycle Recirculating Systems 6-2
6.2.1 Wet Cooling Systems 6-3
6.2.2 Dry Cooling Systems 6-7
6.2.3 Performance of Cooling Towers 6-8
6.2.4 Examples of Cooling Towers 6-11
6.3 Variable speed pumps/variable frequency drives 6-12
6.4 Seasonal Flow Reductions 6-17
6.5 Water Reuse 6-17
6.6 Alternate Cooling Water Sources 6-18
6.7 Screening Technologies 6-18
6.8 Conventional Traveling Screens 6-21
6.8.1 Technology Performance 6-22
6.8.2 Facility Examples 6-22
6.9 Modified Coarse Mesh Traveling Screens 6-22
6.9.1 Screen Design Elements 6-24
6.9.2 Removal and Return System Design Elements 6-27
6.9.3 Operation and Maintenance 6-29
6.9.4 Technology Performance 6-30
6.9.5 Facility Examples 6-31
6.10 Geiger screens 6-34
6.10.1 Technology Performance 6-36
6.10.2 Facility/Laboratory Examples 6-36
6.11 Hydrolox screens 6-36
6.11.1 Technology Performance 6-37
6.11.2 Facility Examples 6-37
6.12 Beaudrey W Intake Protection (WIP) Screen 6-37
6.12.1 Technology Performance 6-38
6.12.2 Facility/Laboratory Examples 6-38
6.13 Coarse Mesh Cylindrical Wedgewire 6-38
6.13.1 Technology Performance 6-40
6.13.2 Facility/Laboratory Examples 6-41
6.14 Barrier nets 6-41
6.14.1 Technology Performance 6-42
6.14.2 Facility Examples 6-42
6.15 Velocity Cap 6-43
6.15.1 Technology Performance 6-45
6.15.2 Facilities/Laboratory Examples 6-47
6.16 Fine Mesh Screens 6-49
6.16.1 Fine Mesh Traveling Screens 6-49
6.16.2 Fine Mesh Wedgewire Screens 6-54
6.17 Aquatic Filter Barrier 6-57
6.17.1 Technology Performance 6-58
6.17.2 Facilities Examples 6-58
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
6.18 Other Technologies and Operational Measures 6-58
6.18.1 Reduce Intake Velocity 6-58
6.18.2 Substratum Intakes 6-59
6.18.3 Louvers 6-59
6.18.4 Intake Location 6-60
6.19 References 6-63
Chapter 7: Regulatory Options 7-1
7.0 Introduction 7-1
7.1 Technology Basis Considered for the Proposed Regulation 7-1
7.1.1 Modified Ristroph Screens 7-1
7.1.2 Barrier Nets 7-2
7.1.3 Closed-cycle Cooling Towers 7-2
7.2 Options Considered 7-3
7.3 BT A Evaluation and Selection of Proposed Standards 7-7
7.4 Site-Specific Studies to Inform the Selection of Appropriate Entrainment
Controls 7-7
Chapter 8: Costing Methodology 8-1
8.0 Introduction 8-1
8.1 Compliance Costs Developed for the Proposed Rule 8-2
8.1.1 Model Facility Approach 8-2
8.2 Impingement Mortality Compliance Costs 8-3
8.2.1 Selection of Technology to Address EVI 8-4
8.2.2 EPA's Cost Tool 8-5
8.2.3 Identifying Intakes That Are Already Compliant With Impingement
Mortality Requirements 8-10
8.2.4 Development of Cost Tool Input Data 8-10
8.3 Entrainment Mortality Compliance Costs 8-15
8.3.1 Capital Costs 8-17
8.3.2 O&M Costs 8-22
8.3.3 Energy Penalty 8-24
8.3.4 Construction Downtime 8-26
8.3.5 Identifying Intakes That Are Already Compliant With Entrainment
Mortality Requirements 8-28
8.4 Entrainment Mortality Compliance Costs for New Units 8-29
8.4.1 Compliance Costs for New Power Generation Units 8-29
8.4.2 Compliance Costs for New Manufacturing Units 8-35
8.5 Impingement Mortality Costs at Intakes with Cooling Systems Required to
Install Closed-Cycle Cooling 8-38
8.6 Costs for Each Regulatory Alternative 8-39
8.7 Compliance Costs Developed for Analysis of National Economic Impacts.... 8-39
8.7.1 Selection of DIP as the Primary Scaling Factor for Power Plants 8-39
8.7.2 Development of EVI&EM Control Costs for IPM Model 8-40
8.7.3 Development of Closed-Cycle Cooling Tower Costs for IPM Model 8-43
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Chapter 9: Impingement Mortality and Entrainment Mortality Reduction
Estimates 9-1
9.0 Introduction 9-1
9.1 Technology Reduction Estimates 9-1
9.1.1 Screens 9-1
9.1.2 Low Intake Velocity 9-1
9.1.3 Barrier Nets 9-2
9.1.4 Flow Reduction Commensurate with Closed-Cycle Cooling 9-2
9.2 Assigning a Reduction to Each Model Facility 9-2
9.2.1 Entrainment Mortality 9-4
9.2.2 In-Place Technologies 9-4
9.2.3 Summary of Options 9-4
Chapter 10: Non-water Quality Impacts 10-1
10.0 Introduction 10-1
10.1 Air Emissions Increases 10-1
10.1.1 Incremental Emissions Increases 10-1
10.1.2 GIS Analysis 10-6
10.2 Vapor Plumes 10-7
10.3 Displacement of Wetlands or Other Land Habitats 10-8
10.4 Salt or Mineral Drift 10-8
10.5 Noise 10-9
10.6 Solid Waste Generation 10-10
10.7 Evaporative Consumption of Water 10-10
10.8 Thermal Effluent 10-11
10.9 References 10-12
Appendix to Chapter 10: Non-water Quality Impacts 10A-1
Chapter 11: Impingement Mortality Limitations and Entrainment Data 11-1
11.0 Introduction 11-1
11.1 Overview of Data Selection 11-1
11.1.1 Data Acceptance Criteria 11-1
11.1.2 Future Data Reviews 11-3
11.2 Proposed Impingement Mortality Limitations 11-4
11.2.1 Impingement Mortality Percentage Data 11-4
11.2.2 Additional Criteria Used to Select Data and Facilities as the Basis for
Impingement Mortality Limitations 11-4
11.2.3 Calculation of Limitations 11-7
11.2.4 Monitoring For Compliance 11-11
11.3 Evaluation of the Entrainment Data 11-12
11.3.1 Entrainment Percent Reduction Data 11-12
11.3.2 Initial Selection and Evaluation of Entrainment Data 11-12
11.3.3 "In Front" and "Behind" Sampling Locations 11-15
11.3.4 Evaluation of Screen Characteristics in Reducing Entrainment 11-18
11.3.5 Consideration of Entrainment Limitation 11-27
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
11.4 References 11-29
Appendix Ato Chapter 11: Studies 11A-1
Appendix B to Chapter 11: Summaries and Analyses of Data from Published
Documents to Assess the Performance of Technologies to Reduce the
Impact of Impingement or Entrainment on Aquatic Life Under Section
316(b) of the Clean Water Act 11B-1
Appendix C to Chapter 11: Impingement and Entrainment Data 11C-1
Appendix D to Chapter 11: Statistical Procedures for Estimating the Mean and
95th Percentile of Impingement Mortality Percentages 1 ID-1
Appendix E to Chapter 11: Analysis of Variance on Percent Reduction in
Entrained Organisms 11E-1
Appendix F to Chapter 11: Generalized Linear Models for Percent Reduction in
Entrained Organisms 11F-1
Chapter 12: Analysis of Uncertainty 12-1
12.0 Introduction 12-1
12.1 Uncertainty in Technical Analysis of Impingement Mortality 12-1
12.1.1 Technology in Place and Related Model Facility Data 12-1
12.1.2 Costs of Additional Impingement Mortality Controls 12-1
12.1.3 Intake Flows for Studies Used to Develop Impingement Mortality
Standards 12-3
12.2 Uncertainty in Technical Analysis of Entrainment Mortality 12-3
12.2.1 Intake Location 12-3
12.2.2 Space Constraints 12-5
12.2.3 Development of Cooling Tower Costs 12-6
12.3 Uncertainty in Benefits of I&E Controls 12-8
12.3.1 Reductions in Impingement and Entrainment by Region 12-8
12.3.2 Air Emissions Associated with Closed-Cycle 12-9
12.4 References 12-12
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Exhibits
Exhibit 2-1. Site Visit Locations and Locations of Other Site-Specific Data
Collected 2-6
Exhibit 2-2. Methods used to address Section 316(a) Requirements by EPA Region 2-21
Exhibit 2-3. Methods used to address Section 316(b) Requirements by EPA Region 2-22
Exhibit 3-1. Applicability by Phase of the 316(b) Rules 3-1
Exhibit 3-2. Applicable Requirements of the Proposed Rule for Existing Facilities 3-1
Exhibit 4-1. Cooling Water Use in Surveyed Industries 4-4
Exhibit 4-2. Map of Facilities Subject to 316(b) 4-4
Exhibit 4-3. Distribution of Facilities by Design Intake Flows 4-5
Exhibit 4-4. Relative Volumes of Design Intake Flow and Average Intake Flow 4-5
Exhibit 4-5. Design Intake Flow by Industry Type 4-6
Exhibit 4-6. Distribution of Source Waterbodies for Existing Facilities 4-6
Exhibit 4-7. Facility Intake Flows as a Percentage of Mean Annual Flow 4-7
Exhibit 4-8. Distribution of Cooling Water System Configurations 4-8
Exhibit 4-9. Distribution of Facilities by Cooling Water System and Waterbody
Type 4-8
Exhibit 4-10. Distribution of Cooling Water System Configurations at Nuclear
Facilities by Waterbody Type 4-9
Exhibit 4-11. Distribution of Cooling Water Intake Structure Arrangements 4-9
Exhibit 4-12. Estimated Distribution of Cooling Water System Configurations as a
Function of Age 4-10
Exhibit 4-13. Estimated Distribution of In-Scope Facilities by the Number of
Cooling Water Systems 4-11
Exhibit 4-14. Estimated Distribution of In-Scope Facilities by the Number of
Cooling Water Intake Structures 4-11
Exhibit 4-15. Electric Generators with Multiple CWISs 4-12
Exhibit 4-16. Estimated Distribution of Screen Mesh Size 4-12
Exhibit 4-17. Distribution of Cooling Water Intake Structure (CWIS) Design
Through-Screen Velocities 4-13
Exhibit 4-18. Estimated Distribution of Intakes by Average of CWIS Operating
Days 4-13
Exhibit 4-19. Distribution of Intake Technologies 4-14
Exhibit 4-20. Age of Electric Generating Units by Fuel Type 4-15
Exhibit 4-22. Number of Existing Utility and Nonutility Facilities by Prime Mover,
2007 4-23
Exhibit 4-23. Summary of 316(b) Electric Power Facility Data 4-24
Exhibit 4-24. Number of 316(b) Regulated Facilities 4-25
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-25. 316(b) Electric Power Facilities by Plant Type and Prime Mover 4-25
Exhibit 4-26. Manufacturers with Coal-Fired Generation 4-26
Exhibit 5-1. Generating Efficiency by Fuel Type 5-2
Exhibit 5-2. Distribution of Intake Flows for All Non-Nuclear Electric Generators 5-3
Exhibit 5-3. Distribution of Intake Flows for All Nuclear Electric Generators 5-4
Exhibit 5-4. Distribution of Nuclear and Non-Nuclear Facilities by Waterbody
Type 5-4
Exhibit 5-5. Distribution of Nuclear and Non-Nuclear Facilities by Cooling System
Type 5-5
Exhibit 5-6. Normalized DIP at Phase II and III Electric Generating Facilities 5-8
Exhibit 5-7. Distribution of Intake Flows for All Electric Generators 5-9
Exhibit 5-8. Distribution of Normalized DIP for All Electric Generators 5-10
Exhibit 5-9. Distribution of DIP (Non-Normalized) for All Electric Generators 5-10
Exhibit 5-10. Distribution of Normalized AIF for All Electric Generators 5-11
Exhibit 5-11. Distribution of AIF (Non-Normalized) for All Electric Generators 5-11
Exhibit 5-12. Distribution of Nameplate Generating Capacity 5-12
Exhibit 5-13. Electric Generators and Flow Addressed By Various Flow Thresholds.... 5-13
Exhibit 5-14. Manufacturers and Flow Addressed By Various Flow Thresholds 5-13
Exhibit 5-15. Facilities and Flow Addressed By Various Flow Thresholds 5-14
Exhibit 5-16. Distribution of Nameplate Generating Capacity 5-14
Exhibit 5-17. Cumulative Distribution of Phase II Facility Year 2000 Generating
Unit Capacity Factors by Primary Fuel Type 5-16
Exhibit 5-18. Distribution of Phase II Facility Year 2000 Generating Unit Capacity
Factors by Generating Unit Prime Mover 5-16
Exhibit 5-19. Phase II Facility Year 2000 Generating Unit Capacity Factors Versus
Nameplate Generating Unit Capacity 5-17
Exhibit 5-20. Phase II Facility Generating Unit Year 2000 Capacity Factor Versus
Year Generating Unit Came Online 5-17
Exhibit 5-21. Distribution of Phase II Facility Year 2000 Total Plant Capacity
Factors by Primary Fuel Type 5-18
Exhibit 5-22. Distribution of Phase II Facility Year 2000 Total Plant Capacity
Factors by Intake Waterbody Type 5-18
Exhibit 5-23. Phase II Facility Year 2000 Total Plant Capacity Factor Versus Total
Generating Capacity 5-19
Exhibit 5-24. Distribution of Capacity Utilization 5-20
Exhibit 5-25. Facilities with CUR Less Than 10 percent 5-21
Exhibit 5-26. Swim Speed Versus Fish Length 5-22
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Exhibit 5-27. Design Intake Flow (gpm) / MW Steam Capacity for Once Through
Power Plants Over 50 MOD 5-23
Exhibit 5-28. Median Water Efficiency (Water Use per MW Generated) of Power
Plants (Including CCRS) 5-24
Exhibit 6-1. List of Technologies Considered 6-2
Exhibit 6-2. Natural draft cooling towers at Chalk Point Generating Station,
Aquasco, MD 6-4
Exhibit 6-3. Mechanical draft cooling towers at Logan Generating Plant,
Swedesboro, NJ 6-4
Exhibit 6-4. Percent Reduction in Flow for Various Cooling System Delta Ts 6-5
Exhibit 6-5. Modular cooling tower (image from Service Tech) 6-6
Exhibit 6-6. Dry cooling tower (image from GEM Equipment) 6-8
Exhibit 6-7. Flow Reduction at Millstone 6-14
Exhibit 6-8. Examples of Seasonal Flow Reductions 6-17
Exhibit 6-9. Generic CWIS With Traveling Screens 6-19
Exhibit 6-10. Traveling screen atEddystone Generating Station, Eddystone, PA 6-20
Exhibit 6-11. Traveling screen diagram 6-20
Exhibit 6-12. Cylindrical wedgewire screen 6-21
Exhibit 6-13. Ristroph and Fletcher Basket Designs 6-24
Exhibit 6-14. Geiger screen (image from EPRI2007) 6-35
Exhibit 6-15. Velocity cap diagram 6-44
Exhibit 6-16. Velocity caps prior to installation at Seabrook Generating Station
(Seabrook, NH) 6-45
Exhibit 6-17. Illustration of Fine Mesh Screen Operation and "Converts" 6-52
Exhibit 6-18. Gunderboom at Lovett Generating Station (image from
Gunderboom) 6-57
Exhibit 7-1. Weighted Pre-Tax Compliance Costs ($2009) by DIF Threshold
(MGD) 7-6
Exhibit 7-2. Number of Facilities by Flow Threshold (MGD) 7-7
Exhibit 8-1. Flow Chart for Assigning Cost Modules for Impingement Mortality
Reduction Requirements for Facilities with Design Intake Flow
>10 MGD Based on Meeting Performance of Modified Ristroph
Traveling Screens 8-7
Exhibit 8-2. Flow Chart for Assigning Cost Modules for Impingement Mortality
Reduction Requirements for Facilities with Design Intake Flow
2-10 MGD Based on Meeting Performance of Modified Ristroph
Traveling Screens 8-8
Exhibit 8-3. Net Construction Downtime for Impingement Mortality Compliance
Technologies 8-10
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 8-4. Input Data Sources and Assumptions 8-11
Exhibit 8-5. Assumed Height of Traveling Screen Deck Above Mean Water Level.... 8-13
Exhibit 8-6. Cooling Tower Costs for Average Difficulty Retrofit 8-18
Exhibit 8-7. Capital and O&M Cost Factors for Average Difficulty Cooling Tower
Retrofit with 25 percent Plume Abatement 8-18
Exhibit 8-8. Cooling Tower Costs for Difficult Retrofit 8-19
Exhibit 8-9. Ratio of Non-Contact Cooling Water Flow to Total Facility Flow for
Evaluated Manufacturing Facilities With DIF > 100 MOD 8-22
Exhibit 8-10. Net Construct!on Downtime 8-27
Exhibit 8-11. Number of Model Facilities/CWISs Classified as Closed-Cycle 8-28
Exhibit 8-12. Estimated Annual New Capacity Subject to New Unit Requirements.... 8-30
Exhibit 8-13. New Capacity Subject to New Unit Requirement by Cost Category 8-31
Exhibit 8-14. Cost Category Distribution of New Coal Capacity 8-32
Exhibit 8-15. Cost Category Distribution of New Combined Cycle Capacity 8-32
Exhibit 8-16. Costs for New Units and Repowering Based on GPM 8-34
Exhibit 8-17 Costs for New Units Based on Generating Capacity 8-35
Exhibit 8-18. Estimation of DIF Where No DIF Data Exists 8-40
Exhibit 8-19. Cost Equations for Estimating Model Facility Costs of
Impingement Mortality Controls for the IPM Analysis for Facilities
with DIF > 10 MOD 8-41
Exhibit 8-20. Cost Equations for Estimating Model Facility Costs of
Impingement Mortality Controls for the IPM Analysis for Facilities
with DIF < 10 MOD 8-41
Exhibit 8-21. Estimated Technology Service Life 8-42
Exhibit 8-22. Technology Downtime and Service Life for Model Facility Costs of
Impingement Mortality Controls for the IPM Analysis 8-43
Exhibit 9-1. Reductions in Impingement Mortality and Entrainment Mortality 9-3
Exhibit 9-2. Summary of Options 9-5
Exhibit 10-1. Phase II facilities in non-attainment areas (by pollutant) 10-7
Exhibit 10-2. Phase II facilities in non-attainment areas (by EPA Region) 10-7
Exhibit 11-1. Candidate Technologies Reviewed in the Documents 11-3
Exhibit 11-2. List of Ex eluded Facilities with Impingement Data 11-5
Exhibit 11-3. Characteristics of Facilities Used As Basis for Impingement
Mortality Limitations 11-6
Exhibit 11-4. Facilities and Data Used As Basis for Monthly Average Limitation on
Impingement Mortality 11-8
Exhibit 11-5. Annual Averages of Impingement Mortality Used to Evaluate
Proposed Annual Average Limitation 11-10
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Exhibit 11-6. Characteristics of Facilities with Entrainment Data and the
Technology Basis 11-14
Exhibit 11-7. Total Organisms: Percent Reduction of Entrainment by Slot Width
and Slot Velocity 11-15
Exhibit 11-8. Collection Locations for "Front" and "Behind" Entrainment Samples.... 11-17
Exhibit 11-9. Percent Reduction of Total Organisms Entrained by Slot Velocity
and Screen Size, with Screen Size on the Horizontal Axis 11-22
Exhibit 11-10. Percent Reduction of Total Organisms Entrained by Slot Velocity
and Screen Size, with Slot Velocity on the Horizontal Axis 11 -22
Exhibit 11-11. Percent Reduction of Eggs Entrained by Slot Velocity and Screen
Size, with Screen Size on the Horizontal Axis 11-23
Exhibit 11-12. Percent Reduction of Eggs Entrained by Slot Velocity and Screen
Size, with Slot Velocity on the Horizontal Axis 11-23
Exhibit 11-13. Eggs: Percent Reduction of Entrainment 11-24
Exhibit 11-14. Percent Reduction of Larvae Entrained by Slot Velocity and Screen
Size, with Screen Size on the Horizontal Axis 11-24
Exhibit 11-15. Percent Reduction of Larvae Entrained by Slot Velocity and Screen
Size, with Slot Velocity on the Horizontal Axis 11-25
Exhibit 11-16. Larvae: Percent Reduction of Entrainment 11-26
Exhibit 11-17. List of Percent Reduction in Entrainment Data by Study, Screen
Size, and Slot Velocity, and Summary Statistics 11-28
Exhibit 11A-1. List of Documents Reviewed for Data on Impingement and
Entrainment For Use in Preparing Proposed Limitations on
Impingement Mortality and BTA Design Standards for Entrainment 11A-2
Exhibit 11 A-2. List of Documents and Facilities with Impingement Mortality Data
(counts and/or percentages) in EPA's Performance Study Database 11A-24
Exhibit 11A-3. List of Documents and Facilities with Entrainment Density Data
("front" and "behind") in EPA's Performance Study Database 11A-25
Exhibit 11A-4. List of Documents and Facilities with Entrainment Mortality Data
(counts and/or percentages) in EPA's Performance Study Database 11A-26
Exhibit 11B-1. Data Summaries on Performance Measures With the Most
Impingement and Entrainment Data Values Within EPA's Performance
Study Database 11B-2
Exhibit 11B-2. Roadmap Used in Identifying Relevant Performance Data for
EPA's Evaluation of Technologies to Reduce Impingement and
Entrainment of Aquatic Organisms 11B-7
Exhibit 11B-3. List of Documents Represented in the Performance Study
Database 11B-10
Exhibit 11B-4. Descriptive Statistics on Percent Mortality Performance Data,
by Technology Category and Mortality Observation Time 11B-26
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 11B-5. Descriptive Statistics on Percent Biomass Performance Data,
by Technology Category 11B-27
Exhibit 11B-6. Descriptive Statistics on Percent Injury Performance Data, by
Technology Category 11B-27
Exhibit 11B-7. Descriptive Statistics on Mortality Count, by Technology
Category and Mortality Observation Time 11B-29
Exhibit 11B-8. Descriptive Statistics on Survival Count, by Technology
Category and Mortality Observation Time 11B-30
Exhibit 11B-9. Descriptive Statistics on Percentage Change from Baseline in
Mortality Count, by Technology Category and Mortality Observation
Time 11B-31
Exhibit 1 IB-10. Descriptive Statistics on Percentage Change from Baseline in
Survival Count, by Technology Category and Mortality Observation
Time 11B-31
Exhibit 11B-11. Descriptive Statistics on Percentage Change from Baseline in
Percent Mortality, by Technology Category and Mortality Observation
Time 11B-32
Exhibit 11B-12. Mean Predicted Values for Percent Mortality Associated with
Entrainment Under Fixed Screen (Fine Mesh), as Estimated from
Mixed Model ANOVA Modeling 11B-35
Exhibit 11B-13. Mean Predicted Values for Percent Mortality Associated with
Entrainment Under Reduced Intake Flows (Other), as Estimated from
Mixed Model ANOVA Modeling 11B-35
Exhibit 11B-14. Mean Predicted Values for Percent Mortality Associated with
Impingement Under Traveling Screens (Coarse Mesh), as Estimated
from Mixed Model ANOVA Modeling 11B-35
Exhibit 11B-15. Mean Predicted Values for Percent Mortality Associated with
Impingement Under Traveling Screens (Fine Mesh), as Estimated
from Mixed Model ANOVA Modeling 11B-36
Exhibit 1 IB-16. Summary of Percent Mortality, Percent Biomass, and Percent
Injury Data Associated with Entrainment, by Technology Category,
Document, and Study (Test Condition) 11B-37
Exhibit 11B-17. Summary of Percent Mortality Data Associated with Entrainment,
by Technology Category, Document, Study (Test Condition), and
Mortality Observation Time 11B-38
Exhibit 11B-18. Summary of Percent Mortality, Percent Biomass, and Percent
Injury Data Associated with Impingement, by Technology Category,
Document, and Study (Test Condition) 11B-39
Exhibit 1 IB-19. Summary of Percent Mortality Data Associated with
Impingement, by Technology Category, Document, Study
(Test Condition), and Mortality Observation Time 11B-43
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§ 316(b) Existing Facilities Proposed Rule - TDD Contents
Exhibit 11B-20. Summary of Percent Mortality, Percent Biomass, and Percent
Injury Data Associated with Diversion (not impingement or
entrainment), by Technology Category, Document, and Study
(Test Condition) 11B-47
Exhibit 11B-21. Summary of Percent Mortality Data Associated with Diversion
(not impingement or entrainment), by Technology Category,
Document, Study (Test Condition), and Mortality Observation Time ....11B-48
Exhibit 11B-22. Summary of Percent Mortality Data for Outcomes Other than
Impingement, Entrainment, or Diversion, by Technology Category,
Document, Study (Test Condition), and Mortality Observation Time ....11B-49
Exhibit 11B-23. Summary of Mortality and Survival Count Data by Technology
Category, Document, Study (Test Condition), and Mortality
Observation Time 11B-51
Exhibit 11B-24. Summary of Calculated Percentage Change from Baseline in
Immediate Mortality and Survival Counts, by Technology Category,
Document, and Study (Test Condition) 11B-56
Exhibit 11B-25. Summary of Calculated Percentage Change from Baseline in
Mortality and Survival Related Measures, by Technology Category,
Document, Study (Test Condition), and Mortality Observation Time ....11B-57
Exhibit 11B-26. Summary of Calculated Percentage Change from Baseline in
Percent Immediate Mortality, by Technology Category, Document,
and Study (Test Condition) 11B-60
Exhibit 11C-1. Impingement Mortality Data Used to Develop the Proposed
Limitations 11C-2
Exhibit 11C-2. Entrainment Data Evaluated in Chapter 11 11C-8
Exhibit 11D-1. Shape of the beta distribution when a = 1 and/? = 1 11D-2
Exhibit 11D-2. Shape of the beta distribution when a = 0.5 and/? = 0.5 11D-2
Exhibit 11D-3. Shape of the beta distribution when a = 5 and/} = 5 11D-3
Exhibit 11D-4. Shape of the beta distribution when a = 5 and ft = 2 11D-4
Exhibit 11D-5. Shape of the beta distribution when a = 1 and/? = 5 11D-4
Exhibit 11D-6. Impingement Mortality Data Used to Calculate Mean and 95*
Percentile of the Beta Distribution in This Example 11D-8
Exhibit 11D-7. Number of Fish Killed: Daily Averages During Sampling Events .... 11D-11
Exhibit 11E-1. Least Squares Means for Percent Reduction in Entrainment
and 95 Percent 11E-4
Exhibit 11E-2. Least Squares Means for Percent Reduction in Entrainment
and 95 Percent 11E-6
Exhibit 12-1. Intake Flows During Screen Performance Testing 12-4
Exhibit 12-2. Average Densities (N/m3) of eggs and ichthyoplankton sampled
at a given maximum depth intervals in the Gulf of Mexico 12-4
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Contents § 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 12-3. Cost Comparison for a 350 MW Plant with Cooling Flow of
200,000 gpm (288 MOD) 12-7
Exhibit 12-4. Impingement and Entrainment Losses Per Unit Flow 12-8
Exhibit 12-5. Changes in Baseline Impingement and Entrainment 12-9
Exhibit 12-6. Map of Non-Attainment Areas for PM10 12-10
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 1: Background
Chapter 1: Background
1.0 Introduction
This chapter provides background information on the development of 316(b) regulations
including the proposed Existing Facilities rule. This chapter describes the goal of the
proposed Existing Facilities rule and provides an overview of the legislative background,
prior 316(b) rulemakings, and associated litigation history leading up to the proposed
rulemaking. This document builds on and updates record support compiled for the Phase I
rule, the remanded 2004 Phase II existing facility rule, and the Phase III rule, including the
Technical Development Documents for each.
1.1 Purpose of Technical Development Document and
Proposed Regulation
The purpose of this Technical Development Document is to provide record support for the
proposed Existing Facilities rule and to describe the methods used by EPA to analyze
various options. The goal of the proposed regulation is to establish national requirements
for cooling water intake structures at existing facilities that implement Section 316(b) of
the CWA. Section 316(b) of the CWA provides that any standard established pursuant to
Section 301 or 306 of the CWA and applicable to a point source must require that the
location, design, construction, and capacity of cooling water intake structures reflect the
best technology available (BTA) for minimizing adverse environmental impact.
EPA first promulgated regulations to implement Section 316(b) in 1976. The U.S. Court of
Appeals for the Fourth Circuit remanded these regulations to EPA which withdrew them,
leaving in place a provision not remanded that directed permitting authorities to determine
BTA for each facility on a case-by-case basis. In 1995, EPA entered into a consent decree
establishing a schedule for taking final action on regulations to implement Section 316(b).
Pursuant to a schedule in the amended decree providing for final action on regulations in
three phases, in 2001, EPA published a Phase I rule governing new facilities. The U.S.
Court of Appeals for the Second Circuit, while generally upholding the rule, rejected the
provisions allowing restoration to be used to meet the requirements of the rule.
Riverkeeper, Inc. v. U.S. EPA, 358 F. 3d 174, 181 (2d Cir.2004) ("Riverkeeper I").
In 2004, EPA published the Phase II rule applicable to existing power plants. Following
challenge, the Second Circuit remanded numerous aspects of the rule to the Agency,
including the Agency's decision to reject closed-cycle cooling as BTA. The Agency made
this determination, in part, based on a consideration of incremental costs and benefits. The
Second Circuit concluded that a comparison of the costs and benefits of closed-cycle
cooling was not a proper factor to consider in determining BTA. Riverkeeper, Inc. v.
U.S.EPA, 475 F. 3d 83 (2d Cir. 2007) ^Riverkeeper II"). In 2008, the U.S, Supreme Court
agreed to review the Riverkeeper II decision limited to a single issue: whether Section
316(b) authorizes EPA to balance costs and benefits in 316(b) rulemaking. In April 2009,
in Entergy Corp. v. Riverkeeper Inc., 129 S. Ct. 1498, 68 ERC 1001 (2009) (40 ER 770,
4/3/09), the Supreme Court ruled that it is permissible under Section 316(b) to consider
l-l
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Chapter 1: Background § 316(b) Existing Facilities Proposed Rule - TDD
costs and benefits in determining the best technology available to minimize adverse
environmental impacts. The court left it to EPA's discretion to decide whether and how to
consider costs and benefits in 316(b) actions, including rulemaking and BPJ
determinations. The Supreme Court remanded the rule to the Second Circuit.
Subsequently, EPA asked the Second Circuit to return the rule to the Agency for further
review.
In 2006, EPA published the Phase III rule. The Phase III rule establishes 316(b)
requirements for certain new offshore oil and gas extraction facilities. In addition, EPA
determined that, in the case of electric generators with a design intake flow of less than 50
MOD and existing manufacturing facilities, 316(b) requirements should be established by
NPDES permit directors on a case-by-case basis using their best professional judgment. In
July 2010, the U. S. Court of Appeals for the Fifth Circuit issued a decision upholding
EPA's rule for new offshore oil and gas extraction facilities. Further, the court granted the
request of EPA and environmental petitioners in the case to remand the existing facility
portion of the rule back to the Agency for further rulemaking. See section 1.2 below for a
more detailed discussion of the history of EPA's actions to address standards for cooling
water intake structures.
EPA is proposing requirements reflecting the best technology available for minimizing
adverse environmental impact, applicable to the location, design, construction, and
capacity of cooling water intake structures for existing facilities. EPA is treating existing
power generating facilities and existing manufacturing and industrial facilities in one
proceeding. This proposed rule applies to all existing power generating facilities and
existing manufacturing and industrial facilities that have the design capacity to withdraw
more than two million gallons per day of cooling water from waters of the United States
and use at least twenty-five (25) percent of the water they withdraw exclusively for cooling
purposes.
1.2 Background
The Federal Water Pollution Control Act, also known as the Clean Water Act (CWA), 33
U.S.C. 1251 et seq., seeks to "restore and maintain the chemical, physical, and biological
integrity of the nation's waters." 33 U.S.C. § 1251(a). Among the goals of the Act is
"wherever attainable, an interim goal of water quality which provides for the
protection and propagation offish, shellfish, and wildlife and provides for
recreation in and on the water..." 33 U.S.C. § 1251(a)(2).
In furtherance of these objectives, the CWA establishes a comprehensive regulatory
program, key elements of which are (1) a prohibition on the discharge of pollutants from
point sources to waters of the United States, except in compliance with the statute; (2)
authority for EPA or authorized States or Tribes to issue National Pollutant Discharge
Elimination System (NPDES) permits that authorize and regulate the discharge of
pollutants; and (3) requirements for effluent limitations and other conditions in NPDES
permits to implement applicable technology-based effluent limitations guidelines and
standards and applicable State water quality standards.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 1: Background
Section 402 of the CWA authorizes EPA (or an authorized State or Tribe) to issue an
NPDES permit to any person discharging any pollutant or combination of pollutants from a
point source into waters of the United States. Forty-six States and one U.S. territory are
authorized under Section 402(b) to administer the NPDES permitting program. NPDES
permits restrict the types and amounts of pollutants, including heat that may be discharged
from various industrial, commercial, and other sources of wastewater. These permits
control the discharge of pollutants by requiring dischargers to meet technology-based
effluent limitations guidelines (ELGs) or new source performance standards (NSPS)
established pursuant to Section 301 or Section 306. Where such nationally applicable
ELGs or NSPS exist, permit authorities must incorporate them into permit requirements.
Where they do not exist, permit authorities establish effluent limitations and conditions,
reflecting the appropriate level of control (depending on the type of pollutant) based on the
best professional judgment of the permit writer. Limitations based on these guidelines,
standards, or on best professional judgment are known as technology-based effluent limits.
Where technology-based effluent limits are inadequate to meet applicable State water
quality standards, Section 301(b)(l)(C) of the Clean Water Act requires permits to include
more stringent limits to meet applicable water quality standards. NPDES permits also
routinely include standard conditions applicable to all permits, special conditions, and
monitoring and reporting requirements. In addition to these requirements, NPDES permits
must contain conditions to implement the requirements of Section 316(b).
Section 510 of the Clean Water Act provides, that except as provided in the Clean Water
Act, nothing shall preclude or deny the right of any State (or political subdivision thereof)
to adopt or enforce any requirement respecting control or abatement of pollution; except
that if a limitation, prohibition or standard of performance is in effect under the Clean
Water Act, such State may not adopt any other limitation, prohibition, or standard of
performance which is less stringent than the limitation, prohibition, or standard of
performance under the Act. EPA interprets this to reserve for the States authority to
implement requirements that are more stringent than the Federal requirements under state
law. PUD No. 1 of Jefferson County v. Washington Dep't of Ecology, 511 U.S. 700, 705
(1994).
Sections 301, 304, and 306 of the CWA require that EPA develop technology-based
effluent limitations guidelines and new source performance standards that are used as the
basis for discharge requirements in wastewater discharge permits. EPA develops these
effluent limitations guidelines and standards for categories of industrial dischargers based
on the pollutants of concern discharged by the industry, the degree of control that can be
attained using various levels of pollution control technology, consideration of various
economic tests appropriate to each level of control, and other factors identified in Sections
304 and 306 of the CWA (such as non-water quality environmental impacts including
energy impacts). EPA has promulgated regulations setting effluent limitations guidelines
and standards under Sections 301, 304, and 306 of the CWA for more than 56 industries.
See 40 CFR parts 405 through 471. EPA has established effluent limitations guidelines
and standards that apply to most of the industry categories that use cooling water intake
structures (e.g., steam electric power generation, paper and allied products, petroleum
refining, iron and steel manufacturing, and chemicals and allied products).
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Chapter 1: Background § 316(b) Existing Facilities Proposed Rule - TDD
Section 316(b) states, in full:
Any standard established pursuant to Section 301 or Section 306 of [the Clean
Water] Act and applicable to a point source shall require that the location, design,
construction, and capacity of cooling water intake structures reflect the best
technology available for minimizing adverse environmental impact.
Section 316(b) addresses the adverse environmental impact caused specifically by the
intake of cooling water, rather than discharges into water. Despite this special focus, the
requirements of Section 316(b) remain closely linked to several of the core elements of the
NPDES permit program established under Section 402 of the CWA to control discharges
of pollutants into navigable waters. Thus, while effluent limitations apply to the discharge
of pollutants by NPDES-permitted point sources to waters of the United States, Section
316(b) applies to facilities subject to NPDES requirements that also withdraw water from a
water of the United States for cooling and that use a cooling water intake structure to do so.
The CWA does not describe the factors to be considered in establishing Section 316(b)
substantive performance requirements that reflect the "best technology available for
minimizing adverse environmental impact." The most recent guidance in interpreting
316(b) comes from the U.S. Supreme Court's decision in Entergy Corp. v. Riverkeeper,
Inc. As noted, the decision was limited to the single question of whether Section 316(b) of
the Clean Water Act authorizes EPA to compare costs and benefits of various technologies
when setting national performance standards for cooling water intake structures under
Section 316(b) of the Clean Water Act. In Riverkeeper II, the Second Circuit rejected
EPA's determination that closed-cycle cooling was not BTA because it could not
determine whether EPA had improperly considered costs and benefits in its 316(b)
rulemaking. The Supreme Court reversed and remanded the Second Circuit ruling in a 6-3
opinion authored by Justice Scalia. The Court held that it is reasonable for EPA to conduct
a cost-benefit analysis in setting national performance standards for cooling water intake
structures under Section 316(b). The Court held that EPA has the discretion to consider
costs and benefits under Section 316(b) but is not required to consider costs and benefits.
The Court's discussion of the language of Section 316(b) - Section 316(b) is
"unencumbered by specified statutory factors" — and its critique of the Second Circuit's
decision affirms EPA's broader discretion to consider a number of factors in standard
setting under Section 316(b). While the Supreme Court's decision is limited to whether or
not EPA may consider one factor (cost/benefit analysis) under Section 316(b), the
language also suggests that EPA has wide discretion in considering factors relevant to
316(b) standard setting. ("It is eminently reasonable to conclude that § J326b's silence is
meant to convey nothing more than a refusal to tie the agency's hands as to whether
cost-benefit analysis should be used, and if so to what decree." (emphasis supplied), 129
S.Ct. 1498, 1508 (2009).
Regarding the other factors EPA may consider, Section 316(b) cross references Sections
301 and 306 of the CWA by requiring that any standards established pursuant to those
sections also must require that the location, design, construction and capacity of intake
structures reflect BTA. Thus, among the factors EPA may use to determine BTA, EPA
may look to similar phrases used elsewhere in the CWA. See Riverkeeper v. EPA, (2nd
Cir. Feb. 3, 2004). Section 306 directs EPA to establish performance standards for new
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 1: Background
sources based on the "best available demonstrated control technology" (BADT). 33
U.S.C. 13 16(a)(l). In establishing BADT, EPA "shall take into consideration the cost of
achieving such effluent reduction, and any non-water quality environmental impact and
energy requirements." 33 U.S.C. 1316(b)(2)(B). The specific cross-reference in CWA
Section 3 16(b) to CWA Section 306 "is an invitation to look to Section 306 for guidance in
discerning what factors Congress intended the EPA to consider in determining the 'best
technology available'" for new sources.
Similarly, Section 301 of the CWA requires EPA to establish standards known as "effluent
limitations" for existing point source discharges in two phases. In the first phase,
applicable to all pollutants, EPA must establish effluent limitations based on the "best
practicable control technology currently available" (BPT). 33 U.S.C. 1311(b)(l)(A). In
establishing BPT, the CWA directs EPA to consider the total cost of application of
technology in relation to the effluent reduction benefits to be achieved from such
application, and shall also take into account the age of the equipment and facilities
involved, the process employed, the engineering aspects of the application of various types
of control techniques, process changes, non-water quality environmental impact (including
energy requirements), and such other factors as [EPA] deems appropriate. 33 U.S.C.
In the second phase, EPA must establish effluent limitations for conventional pollutants
based on the "best conventional pollution control technology" (BCT), and for toxic
pollutants based on the "best available technology economically achievable" (BAT). 33
U.S.C. 1311(b)(2)(A), (E).
In determining BCT, EPA must consider, among other factors,
"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 from publicly owned treatment
works to the cost and level of reduction of such pollutants from a class or category
of industry source. . . . and the age of equipment and facilities involved, the process
employed, the engineering aspects .... of various types of control techniques,
process changes, the cost of achieving such effluent reduction, non-water quality
environmental impacts (including energy requirements), and such other factors as
[EPA] deems appropriate." 33 U.S.C. 1314(b)(4)(B).
In determining BAT, the CWA directs EPA to consider "the age of equipment and facilities
involved, the process employed, the engineering aspects .... of various types of control
techniques, process changes, the cost of achieving such effluent reduction, non-water
quality environmental impacts (including energy requirements), and such other factors as
[EPA] deems appropriate." 33 U.S.C. 1314(b)(2)(B).
Section 3 16(b) expressly refers to Section 301, and the phrase "best technology available"
is very similar to the phrases "best available technology economically achievable " and
"best practicable control technology currently available" in that section. Thus, Section
316(b), Section 301(b)(l)(A) - the BPT provision- and Section 301(b)(l)(B) - the BAT
provision — all include the terms "best," "technology," and "available," but neither BPT
nor BAT goes on to consider minimizing adverse environmental impacts, as BTA does.
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Chapter 1: Background § 316(b) Existing Facilities Proposed Rule - TDD
See 33 U.S.C. 131 l(b)(l)(A) and (2)(A). These facts, coupled with the brevity of Section
316(b) itself, prompts EPA to look to Section 301 and, ultimately, Section 304 for further
guidance in determining the "best technology available to minimize adverse environmental
impact" of cooling water intake structures for existing facilities.
By the same token, however, there are significant differences between Section 316(b) and
Sections 301 and 304. See Riverkeeper, Inc. v. United States Environmental Protection
Agency (2nd Cir. Feb. 3, 2004) ("not every statutory directive contained [in Sections 301
and 306] is applicable" to a Section 316(b) rulemaking). Moreover, as the Supreme Court
recognized, while the provisions governing the discharge of toxic pollutants must require
the elimination of discharges if technically and economically achievable, Section 316(b)
has the less ambitious goal of "minimizing adverse environmental impact." 129 S.Ct.
1498, 1506. In contrast to the effluent limitations provisions, the object of the "best
technology available" is explicitly articulated by reference to the receiving water: to
minimize adverse environmental impact in the waters from which cooling water is
withdrawn. This difference is reflected in EPA's past practices in implementing Sections
301, 304, and 316(b). EPA has established BPT and BAT effluent limitations guidelines
and NSPS based on the efficacy of one or more technologies to reduce pollutants in
wastewater in relation to their costs without necessarily considering the impact on the
receiving waters. This contrasts to 316(b) requirements, where EPA has previously
considered the costs of technologies in relation to the benefits of minimizing adverse
environmental impact in establishing 316(b) limits, which historically has been done on a
case-by case basis. In Re Public Service Co. of New Hampshire, 10 ERC 1257 (June 17,
1977); In Re Public Service Co. of New Hampshire, 1 EAD 455 (Aug. 4, 1978); Seacoast
Anti-Pollution League v. Costle, 597 F. 2d 306 (1st Cir. 1979) EPA concluded that,
because both Section 301 and 306 are expressly cross-referenced in Section 316(b), EPA
reasonably interpreted Section 316(b) as authorizing consideration of the same factors,
including costs, as in those sections. EPA interpreted "best technology available" to mean
the best technology available at an "economically practicable" cost. This approach
squared with the limited legislative history of Section 316(b) which suggested the BTA
was to be based on technology whose costs were "economically practicable." In debate on
Section 316(b), one legislator explained that "[t]he reference here to 'best technology
available' is intended to be interpreted to mean the best technology available commercially
at an economically practicable cost'' 118 Cong. Rec. 33,762 (1972) (statement of Rep.
Clausen) (emphasis added).
For EPA's initial Phase II rulemaking, as it had during 30 years of BPJ Section 316(b)
permitting, EPA therefore interpreted CWA Section 316(b) as authorizing EPA to consider
not only the costs of technologies but also their effects on the water from which the cooling
water is withdrawn.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
Chapter 2: Summary of Data Collection Activities
2.0 Introduction
In developing the proposed rule, EPA used previously collected data from the Phase I,
2004 Phase II, and Phase III rulemakings in combination with newly collected data and
information. This chapter first provides information on major data collection activities
from the previous rulemakings and then provides summaries of information obtained
through more recent data collection activities.
2.1 Primary Data Sourced from Previous 316(b) Rulemakings
This section summarizes the major data collection activities conducted during
development of the Phase I, 2004 Phase II, and Phase III rulemakings that EPA also
considered in developing this proposed rule. For additional, more detailed information
on these previous activities, see the Phase I proposed rule (65 FR 49070), Phase INODA
(66 FR 28853), Phase II proposal (67 FR 17131), Phase II NODA (68 FR 13524), Phase
III proposal (69 FR 68457), Phase III NODA (70 FR 71057), Phase III final (71 FR
35018), and Phase III final TDD (Chapter 3).
2.1.1 Survey Questionnaires
Industry characterization data, including facility-specific technical and financial
information, for the proposed rule and EPA's Phase I, 2004 Phase II, and Phase III
rulemakings was collected through an industry-wide survey conducted in 2000.l This
information was fundamental to EPA's development of its previous rulemakings and is
similarly fundamental to the proposed Existing Facilities rule. EPA has relied on the
previously collected technical (e.g., cooling water system data and cooling water intake
configuration specifications and intake flow rates) and financial information.2'3
Two types of surveys were issued: detailed questionnaires (DQ) and short technical
questionnaires (STQ). Detailed questionnaires were longer and requested more specific
information about technologies, plant operations, and other characteristics. Short
technical questionnaires were developed as a way to statistically sample a larger number
of facilities while maintaining a manageable burden on the industry respondents; these
surveys contained far less detailed information.
1 For the Phase III rule, EPA issued industry questionnaires to offshore industries (see 69 FR 68458).
2 Specific details about the questions are found in EPA's Information Collection Request (DCN 3- 3084-
R2 in Docket W-00-03) and in the questionnaires (see DCN 3-0030 and 3- 0031 in Docket W-00-03 and
the Docket for the proposed Existing Facilities rule); these documents are also available on EPA's web site
(http://water. epa.gov/lawsregs/lawsguidance/cwa/316b/question_index. cfiri)
3 EPA did update some of the financial information. For a discussion of financial data used, see the EBA.
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Chapter 2: Summary of Data Collection § 316(b) Existing Facilities Proposed Rule - TDD
2.1.2 Technology Efficacy Data
EPA compiled a database of cooling water intake structure technology performance
information otherwise known as the Technology Efficacy Database (TED) (DCN 6-5000
and FDMS Document ID EPA-HQ-OW-2002-0049-1595). The Technology Efficacy
Database was the result of an extensive literature search supplemented by information
obtained through discussions with state and EPA regional staff, and meetings with
nongovernmental organizations that had conducted national or regional data collection
efforts (e.g., Electric Power Research Institute (EPRI) and Tennessee Valley Authority).
EPA's goal in developing this database was to collect information and data to evaluate
the performance of various impingement and entrainment control technologies. The
resulting database contains over 150 records from over 90 documents that include
narrative descriptions of biological sampling information and efficacies for a range of
impingement and entrainment minimization technologies. See Chapter 4 of the TDD for
the 2004 Phase II Final rule for a complete description of this database.
2.1.3 Existing Data Sources
In developing 316(b) regulations, EPA used existing data sources, where available and
applicable. This includes information collected by other Federal agencies as well as data
compiled by private companies. Additional details are found in the 2002 proposed Phase
II rule at 67 FR17131, but the sources contacted include:
• Federal Energy Regulatory Commission (FERC);
• Energy Information Administration (EIA);
• Rural Utility Service (RUS);
• U.S. Nuclear Regulatory Commission (NRC);
• Utility Data Institute;
• NEWGen database;
• Electric Power Research Institute (EPRI); and
• Edison Electric Institute (EEI).
2.1.4 Public Participation Activities
Historically, EPA has worked extensively with stakeholders from industry, public interest
groups, state agencies, and other Federal agencies in the development of previous 316(b)
rulemakings, including numerous meetings with individual stakeholder groups. These
public participation activities focused on various Section 316(b) issues including biology,
technology, and implementation issues. For example, EPA has conducted public
meetings focused on technology, cost and mitigation issues, a technical symposium
sponsored by EPRI and a symposium on cooling water intake structure technologies. See
the 2002 proposed Phase II rule (68 FR 17127) for a discussion of these and other public
participation activities.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
EPA has also issued nine Federal Register notices regarding the 316(b) regulation
development process.4 As a result, EPA has received over 350 public comments from
environmental groups, industry associations, facility owners, state and Federal agencies,
and private citizens.
2.2 New Data Collected
For the proposed Existing Facilities rule, EPA supplemented its previous data collection
activities. EPA collected updated information on various aspects of the rulemaking.
However, in an effort to better inform its BTA determination, EPA's main focus was on
the performance of impingement and entrainment technologies.
2.2.1 Site Visits
As documented in the 2004 Phase II rule, EPA conducted site visits to 22 power plants in
developing the 2004 rule. See 67 FR 17134. Since 2007, EPA has conducted over 50
site visits to power plants and manufacturing sites. The purpose of these visits was to:
gather information on the intake technologies and cooling water systems in place at a
wide variety existing facilities; better understand how the site-specific characteristics of
each facility affect the selection and performance of these systems; gather data on the
performance of technologies and affected biological resources; and to solicit perspectives
from industry representatives.
While visiting certain sites, EPA also collected information on 7 additional facilities that
staff did not physically visit; usually, these were other facilities that were owned by the
parent company of a site visited by EPA. EPA further met with representatives of other
companies or owners of specific power plant or manufacturing sites at EPA Headquarters
in Washington DC.
In general, EPA visited a wide variety of sites representative of the industries and
facilities subject to the proposed rule. Copies of the site visit reports (which provide an
overall facility description as well as detailed information on electricity generation, the
facility's cooling water intake structure and associated fish protection and/or flow
reduction technologies, impingement and/or entrainment sampling and associated data,
and a discussion of the possible application of cooling towers) for each site are provided
in the docket for the proposed rule. Where possible, EPA made these reports publicly
available well before publication of the proposed rule. A list of the facilities visited by
EPA is provided below; Exhibit 2-1 shows the geographic representation of facilities
visited by EPA as well as facilities for which EPA collected site-specific information.
4 See 65 FR 49060, 66 FR 28853, 66 FR 65256, 67 FR 17122, 68 FR 13522, 69 FR 41576, 69 FR 68444,
70 FR 71057, and 71 FR 35006. Also see the EBA for a discussion of the Federal Register notices for
economics-related issues.
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Chapter 2: Summary of Data Collection
§ 316(b) Existing Facilities Proposed Rule - TDD
The sites visited by EPA include the following:
Facility Name State Date Of Visit
El Segundo CA 9/1/2009
Haynes CA 9/2/2009
San Onofre CA 9/2/2009
Scattergood CA 8/31/2009
Valero (Delaware City) DE 7/15/2009
Big Bend FL 3/27/2008
St. Lucie FL 3/26/2008
Harlee Branch GA 2/11/2009
McDonough GA 2/11/2009
Council Bluffs IA 3/2/2009
Crawford IL 8/4/2009
Arcelor Mittal (Indiana Harbor) IN 8/3/2009
Cargill (Hammond) IN 8/3/2009
US Steel (Gary) IN 8/4/2009
Nearman Creek KS 3/3/2009
Quindaro KS 3/3/2009
Dow (Louisiana Operations/Plaquemine) LA 1/12/2010
Dow (St Charles) LA 1/13/2010
Chalk Point MD 12/3/2007
Labadie MO 3/4/2009
Lake Road MO 3/3/2009
Meramec MO 3/4/2009
Brunswick NC 1/28/2008
Nebraska City NE 3/2/2009
North Omaha NE 3/2/2009
Seabrook NH 4/17/2008
Linden NJ 5/26/2010
Logan NJ 1/22/2008
Mercer NJ 5/26/2010
Salem NJ 1/22/2008
Beaver Falls NY 4/1/2008
Danskammer NY 4/16/2008
East River NY 4/15/2008
Ginna NY 4/3/2008
Nine Mile Point NY 4/2/2008
Oswego NY 4/2/2008
WheelabratorWestchester NY 4/16/2008
Eddystone PA 1/23/2008
Sunoco (Marcus Hook) PA 7/14/2009
Sunoco (Philadelphia) PA 7/14/2009
Canadys SC 2/10/2009
Wateree SC 2/10/2009
Williams SC 2/9/2009
Barney Davis TX 3/3/2008
Chesterfield VA 3/10/2009
North Anna VA 4/28/2009
Possum Point VA 3/10/2009
Potomac VA 12/3/2007
Surry VA 1/28/2008
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
Data was also provided by the following facilities:
Facility Name State
Alamitos CA
Contra Costa CA
Diablo Canyon CA
Encina CA
Huntington Beach CA
Mandalay CA
Morro Bay CA
Moss Landing CA
Ormond Beach CA
Pittsburg CA
Potrero CA
Redondo Beach CA
South Bay CA
Diablo Canyon CA
Brayton Point MA
General Electric (Lynn) MA
Georgia Pacific multiple
Hope Creek NJ
Oyster Creek NJ
Indian Point NY
Elm Road Wl
Oak Creek Wl
Harbor CA
Yates GA
Fisk IL
Callaway MO
Hawthorn MO
latan MO
Sibley MO
Sioux MO
Cooper NE
Fort Calhoun NE
Winnetka IL
Brooklyn Navy Yard NY
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§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 2-1. Site Visit Locations and Locations of Other Site-Specific Data
Collected
Site Visit Data Collected By EPA
Legend
EPA Site Visit
• Other data collection
• Secondary site data collected during site visits
EPA used a wide variety of criteria in selecting the sites to visit including the following
factors:
• Industry sector: In 2007, EPA met with several trade associations to discuss data
and information sources that would be useful to EPA as it updated analyses. EPA
solicited industry recommendations for criteria for selecting sites, as well as
suggestions for specific sites. Among generators, EPA visited facilities owned by
utilities, non-utilities, and municipalities. For manufacturers, EPA visited a steel
mill, several petroleum refineries, several chemical manufacturers, and a food
processing facility.5
• Facility location: EPA visited facilities in 8 EPA Regions and 20 states.
Facilities were located on all types of waterbodies (ocean, estuary/tidal river,
lake/reservoir, Great Lake and freshwater river). EPA also visited facilities on
5 EPA was unable to schedule a visit to a pulp and paper facility prior to publishing the proposed rule, but
based on the Agency's experience with other regulatory activities (including the Pulp and Paper Effluent
Limitations Guideline) does not believe that this industry sector is remarkably different from other
manufacturers in terms of cooling water intake structures. EPA also met with Georgia Pacific and the
American Pulp and Paper Association to better understand the use of cooling water and cooling water
intake structures for this industry sector.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
major waterbodies, such as the Missouri/Mississippi Rivers, the Gulf of Mexico,
the Chesapeake Bay, and both the Pacific and Atlantic Oceans.
• Intake technology: Selected sites employed a wide range of intake technologies,
including coarse and fine mesh traveling screens, Ristroph traveling screens,
coarse and fine mesh wedgewire screens, offshore velocity caps, and barrier nets.
Sites also employed a variety of intake configurations, including shoreline,
offshore, and intake canals.
• Cooling system technology: Most facilities visited employ once-through cooling,
but EPA also visited multiple sites with closed-cycle cooling systems. Some
facilities were designed and constructed as closed-cycle systems, while other sites
retrofitted to closed-cycle cooling; some sites used combination cooling systems.
EPA also visited sites with helper cooling towers.
• Logistics: Proximity to EPA Headquarters was a cost-effective way for multiple
EPA staff to attend site visits. For non-local travel, proximity of sites to one
another enabled clustered site visits, reducing travel costs and maximizing staff
time onsite.
• Biological data: Most facilities were selected because they had conducted some
form of impingement or entrainment study in recent years.
• Fuel or generation type: Selected sites used a variety of fuel types (coal, natural
gas, nuclear, municipal waste). Most generated power through steam generation,
but EPA also visited several combined cycle facilities.
• Facility size: EPA visited sites of all sizes, with a wide range of generating
capacity (MW), intake flow, and land area. Additionally, EPA visited sites in
rural areas, industrial areas, and in highly urbanized environments.
In summary, EPA learned the following from the site visits:
• A majority of facilities use coarse mesh screens. However, the screens are
principally used to protect the facility from debris; as such facilities do not always
optimize operation of the screens to protect fish;
• Costs are paramount to facility owners, as any costs could potentially impact
planning and business decisions;
• While site-specific characteristics may set some facilities apart, most facilities
were found to be very similar in how they use cooling water, how the intake
technologies were selected and constructed, and challenges facilities faced in
operating CWIS technologies;
• Long-term planning is important to facilities to maintain reliable energy supplies
(issues such as repowering, air rules, increased energy demand, control of green
house gas (GHG) emissions, and local transmission issues have long-term
implications);
• Closed-cycle cooling, while potentially expensive for some sites, is technically
feasible at most sites;
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• Some manufacturing facilities may use cooling water for contact cooling (such as
quench water). Contact cooling is rarely observed at power plants.
• Manufacturers have different opportunities to reduce and reuse cooling water. In
some cases, manufacturers have reduced total water withdrawals by more than
half.
During the site visits, EPA collected current facility information including power
generation, capacity, and fuel source; permit status; cooling water usage; and cooling
water intake structure and IM&E technologies and controls (including design, operation,
and installation and operational cost information, where available). Through the site
visits, EPA gained a more thorough understanding of the operation of the various IM&E
technologies and controls including challenges, or lack thereof, and efficacy. EPA also
gained more detailed information on any IM&E performance studies at each site, and,
ultimately, the performance data. EPA additionally obtained information on the
application of the suspended Phase II rulemaking. For example, EPA requested
information on how each facility planned to comply with the suspended 2004 rule, and
what challenges might have resulted from implementation of the suspended rule at each
facility. Finally, EPA also gained a better understanding of the possible application of
closed-cycle cooling at each facility. As a result of these site visits, EPA gained valuable
information covering a wide range of topics. Several facilities provided National
Pollutant Discharge Elimination System (NPDES) permit application data originally
intended for submission under the 2004 Phase II rule. These studies typically included
Proposals for Information Collection as well as portions of Comprehensive
Demonstration Studies. Several facilities also provided technology efficacy data or
impingement and entrainment data. Some provided IM&E feasibility studies as well.
Following each visit, EPA prepared a site visit report. These reports document the
information EPA collected through each site visit and its discussions with facility
representatives. Each facility was given the opportunity to review and comment on these
reports. Where the information is not claimed to be confidential, these reports are
available in the record.
EPA also visited Alden Laboratories in Holden, Massachusetts.
2.2.2 Data Provided to EPA by Industrial, Trade, Consulting,
Scientific or Environmental Organizations or by the General
Public
EPA has continued to work with various stakeholders in developing the proposed
Existing Facilities rule. Through these interactions, EPA has received additional data and
information including, but not limited to, the following: technology efficacy data,
operating information, cost information, feasibility, and non-water quality related impact
information.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
EPRI and Industry
EPA met several times with representatives from EPRI and industry on topics ranging
from the feasibility and cost of installing cooling towers at certain facilities, current
studies of impingement on the Ohio River, and the latest advancements in fish protection
technologies for traveling screens. Alden Laboratories also participated in some of these
meetings and provided a status report on the latest advancements in fish protection at
cooling water intake structures. EPA reviewed over 40 EPRI or EPRI-funded studies
dated between 1985-2008, including multiple studies since the publication of the 2004
Phase II rule, including:6
• Fish Protection at Cooling Water Intakes: A Technical Reference Manual (2007)
(DCN 10-6813)
• Net Environmental and Social Effects of Retrofitting Power Plants with Once-
Through Cooling to Closed-Cycle Cooling (2008) (DCN 10-6927)
• Beaudrey Water Intake Protection (WIP) Screen Pilot-Scale Impingement
Survival Study (2009) (DCN 10-6810)
• Comparison of Alternate Cooling Technologies for U.S. Power Plants: Economic,
Environmental, and Other Tradeoffs (2004) (DCN 10-6961)
• Laboratory Evaluation of an Aquatic Filter Barrier for Protecting Early Life
Stages of Fish (2004) (DCN 10-6815)
• Field evaluation of wedgewire screens for protecting early life stages at cooling
water intake structures: Chesapeake Bay studies (2006) (DCN 10-6806)
• Laboratory evaluation of modified Ristroph traveling screens for protecting fish at
cooling water intakes (2006) (DCN 10-6801)
• Design considerations and specifications for fish barrier net deployment at
cooling water intake structures (2006) (DCN 10-6804)
• Laboratory evaluation of fine-mesh traveling water screens for protecting early
life stages offish at cooling water intakes (2008) (DCN 10-6802)
• Latent impingement mortality assessment of the Geiger Multi-Disc screening
system at Potomac River Generating Station (2007) (DCN 10-6814)
• The role of temperature and nutritional status in impingement of clupeid fish
species (2008) (DCN 10-6970)
• Cooling Water Intake Structure Area-of-Influence Evaluations for Ohio River
Ecological Research Program Facilities (2007) (DCN 10-6971)
Materials from some of these meetings (e.g., PowerPoint presentations and demonstration
movies) are available at DCNs 10-6816 to 10-6828.
EPA also received Closed-Cycle Cooling System Retrofit Study: Capital and Performance Cost Estimates
(2011) but it was received too late to be fully considered for the proposed rule.
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Vendors
EPA also contacted cooling water intake structure technology vendors to investigate the
use of several new technologies for potential application at existing facilities. EPA
contacted the following technology vendors:
• Beaudrey screens (DCN 10-6606)
• Hydrolox screens (DCN 10-6807)
• Passavant (Geiger) screens (DCNs 10-6601A and B)
• Hendricks screens (DCNs 10-6601C and D)
• EEVICO screens
• Agreco (modular cooling towers) (DCNs 10-6647 and 6677)
• Blue Stream Services (modular cooling towers) (DCN 10-6677)
• EEA (substratum intakes) (DCN 10-6609)
• Gunderboom
Vendors provided information on design, operation, and efficacy of these technologies as
well as capital and O&M costs. See the record for the proposed Existing Facilities rule
for this information.
2.2.3 Updated Technology Database
As discussed in Section 2.1.2 and in the 2002 proposed Phase II rule (68 FR 13538-
13539), EPA previously developed a Technology Efficacy Database in an effort to
document and assess the performance of various technologies and operational measures
(other than closed-cycle cooling7) designed to minimize the impacts of cooling water
withdrawals (see DCN 6-5000 in the docket for the 2004 Phase II rule). EPA has since
created an updated performance database. In creating the updated database, EPA's
objective was to review the methods used to generate data in these studies and to
combine relevant data across studies in order to produce statistical estimates of the
overall performance of each of the technologies.
In developing the updated database, EPA considered data from over 150 documents.
This includes documents previously contained in EPA's 316(b) rulemaking records as
well as new documents obtained during development of the proposed Existing Facilities
rule. Some of the documents are compilations of multiple studies, such as, EPRI's 2007
Fish Protection at Cooling Water Intakes: A Technical Reference Manual (DCN 10-
6813), which includes results of over 100 studies. Others are facility-specific studies, or
describe the results of research laboratory experiments conducted in a controlled setting.
These documents contain information on the operation or performance of various forms
and applications of these technologies, typically at a specific facility or controlled setting.
7 EPA developed this database to evaluate possible BTA limitations for intake-based technologies. EPA
did not include closed-cycle cooling in this database because these technologies operate through a
reduction in flow, creating a different set of evaluation criteria.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
The studies presented in these documents were performed by owners of facilities with
cooling water intake structures, organizations that represent utilities and the electric
power industry, and other research organizations.
To address EPA's objectives of bringing information from these documents together to
better assess performance technology performance across different technology categories,
EPA obtained and reviewed these documents for the presence of relevant data. Not all
documents fulfilled this objective. While a document might present data that were
acceptable for use in meeting the document's original objectives, this does not
necessarily imply that these data will meet EPA's current objective to combine data
across multiple sources to better assess performance of the different technology
categories. Thus, it was necessary to establish some general criteria for accepting data
from the documents:
• The data must be associated with technologies for minimizing impingement
mortality or entrainment that are currently viable (as recognized by EPA) for use
by industries with cooling water intake structures that are (or will be) subject to
Section 316(b) regulation.
• The data must represent a quantitative measure (e.g., counts, densities, or
percentages) that is related to the impingement mortality or entrainment of some
life form of aquatic organisms within cooling water intake structures under the
given technology.
For studies meeting the above criteria, EPA populated an MS Access database. Within
this database, each document was distinguished by a unique document ID. The
performance study database consisted of two primary data tables:
• A table containing specific information on a particular study, such as the
document and study IDs, facility name, water body, data classification -
(e.g., impingement mortality, entrainment), technology category, and other test
conditions when specified (e.g., mesh size, intake velocity, flow rate, water
temperature, conditions when the technology is in place, control conditions).
• A table containing the reported performance data for a given study. Each entry in
this table contains one or more performance measures for a particular species
along with other factors when they were specified (e.g., age category, dates or
seasons of data collection, water temperature, velocity, elapsed time to mortality).
EPA used this database to develop performance estimates for certain intake technologies
and to develop national performance based limits for impingement mortality. The
screening criteria, methodology, and subsequent statistical analyses conducted to develop
the proposed national performance limits are discussed in detail in Chapter XI of this
technical development document.
2.2.4 Other Resources
EPA also collected information on cooling water system and cooling water intake
structure-related topics from a variety of other sources.
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a. State Cooling Water Policies
In recent years, several states have developed policies or regulations regarding cooling
water use. EPA did not participate directly in the development of any of these state
activities, but did closely monitor their progress. These state programs are summarized
below.
California
California's Ocean Protection Council (OPC) adopted the April 20, 2006 resolution
called Regarding the Use of Once-Through Cooling Technologies in Coastal Waters
(2006 Resolution, DCN 10-6963) which urged state agencies to "implement the most
protective controls to achieve a 90-95 percent reduction in [impingement and
entrainment] impacts" and analyze the costs and constraints involved with the conversion
of once-through cooling systems to an alternative technology. In February 2008, OPC
completed a study entitled, California's Coastal Power Plants: Alternative Cooling
System Analysis, (DCN 10-6964) which evaluates the feasibility of retrofitting coastal
facilities to closed-cycle cooling towers to mitigate impingement and entrainment
impacts at these sites. EPA reviewed this study to identify site-specific considerations
involved in cooling tower retrofits.
California adopted its final Policy on the Use of Coastal and Estuarine Waters for Power
Plant Cooling on May 4, 2010.
(See http://www.waterboards.ca.gov/water_issues/programs/npdes/cwa316.shtml for
more information). Per the state website, the Policy "establishes technology-based
standards to implement federal Clean Water Act Section 316(b) and reduce the harmful
effects associated with cooling water intake structures on marine and estuarine life. The
Policy will apply to the 19 existing power plants (including two nuclear plants) that
currently have the ability to withdraw over 15 billion gallons per day from the State's
coastal and estuarine waters using a single-pass system, also known as once-through
cooling." The Policy requires that existing facilities reduce their intake flow to a level
commensurate with a wet closed-cycle system; California established a 93 percent
reduction in design flow as the minimum flow reduction, in addition to limiting intake
velocities to 0.5 feet per second (fps).8
California has also proposed an amendment to the final Policy to provide additional
flexibility, particularly with respect to combined-cycle generating units. The state
solicited comments in November 2010, held a public meeting on December 14, 2010, and
is currently evaluating the options.
8 The Policy also contains a Track 2 that permits facilities to demonstrate that compliance with Track 1
(described above) is not feasible; these facilities must reduce impingement mortality and entrainment to at
least 90 percent of the level achievable by compliance with Track 1.
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Delaware
In March 2009, Delaware's House of Representatives introduced House Concurrent
Resolution No. 7 (HCR 7)9; the resolution urges the Delaware Department of Natural
Resources and Environmental Control (DNREC) to "declare that "Closed-cycle" cooling
systems constitute the best technology available for water cooling intake structures" and
"to require that all facilities that operate in Delaware waters and that use cooling water
intake structures to adopt "Closed-cycle" cooling systems as quickly as possible." The
resolution also notes the biological impacts associated with once-through cooling. The
resolution was adopted (as amended) by the state Senate and the state House in June
2009. At the time of publication of the proposed rule, Delaware had not yet enacted a
state regulation, but several facilities had made strides in reducing cooling water flows.
A DNREC permit fact sheet10 noted that the state's largest power plant (Indian River,
located in Millsboro) is closing all three generating units that employ once-through
cooling,11 leaving Indian River with only a closed-cycle cooling system for Unit 4.
During EPA's site visit to the (now closed) Valero refinery in Delaware City, facility
representatives noted that their upcoming NPDES permit would require a substantial flow
reduction.12
New York
In March 2010, New York proposed a policy that would require flow reduction
equivalent to closed-cycle cooling at all existing facilities that withdraw more than 20
MGD.13 New York also requires all new power plants to employ dry cooling systems,
which reduce water withdrawals even further than wet cooling towers. At the time of
publication of the proposed rule, the comment period for New York's proposal had
closed14 but the state had not taken any final action.
b. Individual NPDES Permit Renewals
In addition to state-wide cooling water policies, some recent individual NPDES permits
have incorporated requirements for significant reductions in cooling water flow. The
best-known example is Brayton Point in Somerset, Massachusetts. EPA Region I (which
develops NPDES permits for several non-delegated New England states) issued a final
NPDES permit in October 2003 that required a reduction in cooling water intake flow
and thermal discharges of approximately 95 percent.15 Following several years of
9 See
http://legis.delaware.gov/LIS/LIS145.NSF/93487d394bc01014882569a4007a4cb7/674b902d7832ddd7852
57583005af947?OpenDocument
10 See http://www.wr.dnrec.delaware.gov/SiteCollectionDocuments/IRGS%20FactSheet 20100908.pdf.
11 In December 2004, EPA Region III developed a Total Maximum Daily Load (TMDL) for temperature in
the Indian River. The Indian River power plant is the only significant discharger to the receiving stream.
See http://www.epa.gov/reg3wapd/tmdl/de tmdl/IndianRiverTemp/IndianRiverEstablish.pdf and
http://www.epa.gov/reg3wapd/tmdl/de tmdl/IndianRiverTemp/IndianRiverReport.pdf.
12 See DCN 10-6553.
13 See http://www.dec.ny.gov/docs/fish marinejdf/drbtapolicyl.pdf.
14 See http://www.dec.ny.gov/animals/66866.html for the comments received.
15 See http://www.epa.gov/ne/bravtonpoint/index.html.
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appeals and litigation, the facility agreed in December 2007 to implement the
requirements of the permit and is currently constructing two natural draft cooling towers
at the facility.
EPA also visited a number of sites that had retrofitted to closed-cycle cooling for a
variety of reasons.
• McDonough (GA), Yates (GA), Canadys (SC) and Wateree (SC) converted all
generating units to closed-cycle cooling primarily to reduce thermal discharges.
(SeeDCNs 10-6536, 10-6538, 10-6535, and 10-6534, respectively.)
• Nearman Creek (KS) converted its generating units to reduce the need for cooling
water at times of the year when the source water level is low. (See DCN 10-
6524.)
• Linden (NJ) constructed several new combined cycle units to replace retiring
fossil units and uses grey water from a nearby treatment plant for its makeup
water. (See DCN 10-6557.)
While the reasoning for some retrofits may not explicitly include consideration of 316(b),
flow reduction is clearly an issue in the forefront of permitting and operational decisions
at many facilities. Even in cases where 316(b) was not a consideration, the benefits to
aquatic communities are realized nonetheless.
c. International Cooling Water Policy
EPA sought information on how other nations address the impacts from cooling water
withdrawals. (See, e.g., DCNs 10-6620 and 6621). In general, EPA found that many
countries lack an overarching regulatory structure analogous to Section 316(b), so efforts
to address impacts from cooling water intake structures tend to be somewhat inconsistent.
Some countries address the issue on a facility-by-facility basis, while others may make
broader conclusions based on facility location. EPA's research did indicate a distribution
of once-through and closed-cycle cooling systems similar to that found in the U.S.
Lastly, EPA collected a European Union policy on cooling systems (see DCN 10-6846),
which generally advocated that plant efficiency should be the primary decision criterion
in determining the proper cooling system.
d. EPA's 1974 Steam Electric Effluent Limitation Guideline
EPA also reviewed a 1974 ELG for steam electric generators, as this was the Agency's
first attempt at regulating cooling water withdrawals. In the 1974 final ELG (see 39 FR
36186), any existing electric generator built after 1970 with a capacity greater than 500
MW or any generating unit built after 1974 would have been required to retrofit to
closed-cycle cooling; all new units were to be subject to the same standard. EPA's
rationale at the time was that these facilities were relatively new, operated as baseload
facilities, and would be in service for an extended period, thereby justifying the costs to
retrofit. EPA considered many of the same factors in the ELG that it did in developing
the current proposed Existing Facilities rule. The rule was remanded on administrative
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grounds and the subsequent revised ELG (see 47 FR 52290) was silent on cooling water
withdrawals and cooling system types.
2.2.5 Implementation Experience
Following promulgation of the 2004 Phase II rule, states and EPA Regions began to
implement the rule. During that time, EPA worked to assist states in understanding the
rule, develop guidance materials, and support the review of the documentation of the new
requirements. As a result, EPA became aware of certain elements of the 2004 rule that
had become particularly troublesome to implement; as a result, EPA has considered these
challenges and crafted a regulatory framework that the Agency believes is simpler for all
stakeholders to understand and implement.
1. Calculation Baseline
The 2004 Phase II rule required that facilities reduce impingement mortality and
entrainment from the calculation baseline. The calculation baseline was intended to
represent a "typical" Phase II facility and outlined a configuration for a typical CWIS
(See 69 FR 41590). EPA defined the calculation baseline as follows:
"an estimate of impingement mortality and entrainment that would occur at your
site assuming that: the cooling water system has been designed as a once-through
system; the opening of the cooling water intake structure is located at, and the
face of the standard 3/8 inch mesh traveling screen is oriented parallel to, the
shoreline near the surface of the source waterbody; and the baseline practices,
procedures, and structural configuration are those that [a] facility would maintain
in the absence of any structural or operational controls, including flow or velocity
reductions, implemented in whole or in part for the purposes or reducing
impingement mortality and entrainment."
In doing so, a facility that had undertaken efforts to reduce impingement and entrainment
impacts (e.g., by installing a fine mesh screen or reducing intake flow) would be able to
"take credit" for its past efforts and only be required to incrementally reduce
impingement mortality or entrainment to meet the performance standards.
In practice, both permittees and regulatory agencies encountered difficulty with the
calculation baseline, specifically how a facility should determine what the baseline
represented and how a particular facility's site-specific configuration or operations
compared to the calculation baseline. For facilities whose site configuration conforms to
the calculation baseline, it was relatively easy to determine impingement mortality and
entrainment at the conditions representing calculation baseline. However, for facilities
that have a different configuration, estimating a hypothetical calculation baseline could
be difficult. For example, facilities with intake configuration that differed significantly
from the calculation baseline (e.g., a submerged offshore intake) were unsure as to how
to translate their biological and technological data to represent a shoreline CWIS.
Oftentimes facilities encountered difficulty in determining the appropriate location for
monitoring to take place. Other facilities were unsure as to how to take credit for retired
generating units and other flow reductions practices. In site visits, EPA learned that
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facilities with little or no historical biological data encountered a particularly difficult and
time-intensive task of collecting appropriate data and developing the calculation baseline.
As a result, EPA has developed a new approach to the technology-based requirements
proposed today that does not incorporate a calculation baseline.
2. Entrainment Exclusion Versus Entrainment Survival
As EPA worked towards revising the existing facility rules, EPA discovered a nuance to
the performance based requirements of the 2004 Phase II rule: entrainment exclusion
versus entrainment survival. As discussed in section III.C below, EPA re-reviewed the
data on the performance of intake technologies and conducted statistical analysis of the
data. From this analysis, it became apparent that the 2004 Phase II rule did not fully
consider the true performance of intake technologies in affecting "entrainable"
organisms.
By definition, entrainment is the incorporation of aquatic organisms into the intake flow,
which passes through the facility and is then discharged. In order to pass through the
technologies located at the CWIS (e.g., intake screens, nets, etc.), the organisms must be
smaller than the smallest mesh size.l For coarse mesh screens (3/8" mesh size), most
"entrainables" simply pass through the mesh (and through the facility) with only some
contact with the screen.1? In this situation the mortality of organisms passing through the
facility was assumed to be 100 percent, although some facilities have since collected data
showing survival of certain hardier species and lifestages of aquatic organisms.
1 &
However, as mesh sizes are reduced, more and more entrainables will actually become
impinged on the screens (i.e., "converted" from entrainable to impingeable) and would
then be subjected to spray washes and return along with larger impinged organisms as
well as debris from the screens. Under the 2004 Phase II rule, these "converts" would be
classified as a reduction in entrainment, since the entrainment performance standard
simply required a reduction in the number (or mass) of entrained organisms entering the
cooling system. However, for some facilities the low survival rate of converts resulted in
the facility have difficulty complying with the impingement mortality limitations. By
comparison, the performance standard for impingement was measured as impingement
mortality. Organisms that were impinged (i.e., excluded) from the CWIS were typically
washed into a return system and sent back to the source water. In this case, impingement
mortality is an appropriate measure of the biological performance of the technology.
Through EPA's review of control technologies, the Agency found that the survival of
"converts" on fine mesh screens was very poor, and in some extreme cases comparable to
the extremely low survival of entrained organisms that are allowed to pass entirely
16 In the case of many soft-bodied organisms such as eggs and larvae, the force of the intake flow can be
sufficient to bend organisms that are actually larger than the screen mesh and pull them into the cooling
system.
17 Eggs are generally smaller than 2 millimeters in diameter, while larvae head capsids are much more
variable in size, increasing as they mature to the juvenile stage.
18 Fine mesh screens were considered to be one technology that could be used to meet the entrainment
performance standards under the 2004 Phase II rule. EPA also reviewed performance data for screens with
mesh sizes as small as 0.5 mm, as described in section III.C.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
through the facility.19 More specifically, EPA found that most eggs were entrained
unless the mesh slot size was 2.0 mm or less, and mortality of eggs "converted" to
impingement approached 20 to 30 percent. More telling, the mortality of larvae off a fine
mesh screen was rarely less than 80 percent. As a result, a facility with entrainment
exclusion technologies such as fine mesh screens could approach 90 percent
performance, but the subsequent survival of these organisms overall ranged from 0 to 52
percent, and the facility's impingement mortality rates increased. In other words, a
facility that simply excluded entrainable organisms (with no attention being paid to
whether they survive or not) could be deemed to have met its entrainment requirements
under the 2004 Phase II rule, when in fact it may be causing the same level of mortality
as a facility with no entrainment controls at all.
3. Cost-Cost Test
In the 2004 Phase II rule, EPA developed facility-specific cost estimates, and published
those costs in Appendix A (69 FR 41669). The 2004 Phase II rule also included a cost-
cost test (see 69 FR 41644) where a facility could demonstrate that its costs to comply
with the 2004 rule were significantly greater than those that EPA had considered. Since
initial implementation of the July 9, 2004 316(b) Phase II rule, EPA has identified several
concerns with the facility-specific cost as well as the use of that cost in Appendix A.
First, EPA has identified numerous inconsistencies between facility permit applications,
responses in the facility's 316(b) survey, and overall plant capacity as reported in the
most recent EIA database. These inconsistencies resulted in Appendix A costs that were
not comparable to many facility's own compliance cost estimates. In addition, as
described more fully in Chapter 2 of the Technical Development Document, EPA does
not have available technical data for all existing facilities. EPA obtained the technical
data for facilities through industry questionnaires. In order to decrease burden associated
with these questionnaires, EPA requested detailed information from a sample, rather than
a census, of facilities. EPA has concluded that the costs provided in Appendix A are not
appropriate for use in a facility-level cost-cost test. As a result, EPA is not providing a
framework similar to Appendix A in the proposed Existing Facilities rule. (See section
III.C below and VII for more information about how EPA developed compliance costs.)
The impingement mortality requirements of the proposed Existing Facilities rule are
economically achievable,20 and the low variability in the costs of EVI controls at a facility
makes such a provision ineffectual. Furthermore, the proposed Existing Facilities rule
requirements for entrainment mortality requires facilities to submit facility-specific
compliance cost estimates. The determination of whether the cost of specific entrainment
mortality technologies is too high is made by the Director on a case-by-case basis;
accordingly a cost-cost provision is unnecessary.
19 Through-plant entrainment survival has been studied extensively, with EPRFs Review of Entrainment
Survival Studies being amongst the most comprehensive. See DCN 2-017A-R7 from the Phase I docket.
20 The Phase II rule found impingement mortality (plus entrainment on certain waterbodies) was
economically achievable; EPA has not identified any reason this revising this conclusion. See Response to
Comment 316bEFR.330.009 in the Phase II Response to Comment Document (DCN 6-5049).
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Chapter 2: Summary of Data Collection § 316(b) Existing Facilities Proposed Rule - TDD
2.2.6 New or Revised Analyses
In addition to collecting new information, EPA has re-evaluated some existing data and
analyses.
1. Review of Study Data/New Performance Database
The standards of the 2004 Phase II regulation required impingement mortality reduction
for all life stages offish and shellfish of 80 to 95 percent from the calculation baseline
(for all Phase II facilities) and entrainment reduction requirements of 60 to 90 percent
(for certain Phase II facilities). EPA based these performance requirements on a suite of
technologies and compliance alternatives.
For the proposed Existing Facilities rule, EPA reanalyzed BTA. This includes, but is not
limited to, a re-analysis of candidate BTA technologies, their effectiveness, their costs,
and their application. This section highlights some of the major changes resulting from
this re-analysis. See Section VI of the preamble for a thorough discussion of EPA's
updated BTA analysis and determination.
a. New Performance Database
As described above, in its Section 316(b) rule development efforts to date, EPA has
gathered industry documents and research publications with information from studies
which evaluated the performance of a range of technologies for minimizing impingement
or entrainment.
EPA subsequently used this database in an attempt to develop impingement mortality and
entrainment limits. However, as described in section VI, the performance data for
screens and other intake technologies did not indicate that those technologies were nearly
as effective at minimizing impingement and entrainment as closed-cycle cooling.
b. Impingement Mortality and Entrainment Technology Performance Estimates
To evaluate the effectiveness of different control technologies and the extent to which the
various regulatory options considered for the proposed Existing Facilities rule minimize
adverse environmental impacts associated with cooling water intake structures, EPA used
the data collected in the new analysis to develop impingement mortality and entrainment
reduction estimates. For some technologies, the proposed Existing Facilities rule reflects
updated information or a different methodology for estimating effectiveness.
1. Cooling Towers
In the 2004 Phase II rule, EPA estimated facilities employing freshwater cooling towers
and saltwater cooling towers would achieve flow reductions, and therefore associated
entrainment and impingement mortality reductions, of 98 percent and 70-96 percent,
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
91
respectively. At that time, EPA's record demonstrated that saltwater cooling towers
typically operated at 1.1-2.0 cycles of concentration. However, more recent information
demonstrates that, as a result of advances in design and operation, saltwater cooling
towers typically operate at 1.5 cycles of concentration or more. This equates to a 94.9
percent reduction in flow over a once through cooling system. To better reflect the
advances in cooling tower design, EPA now estimates that freshwater cooling towers and
saltwater cooling towers reduce impingement mortality and entrainment by 97.5 percent
and 94.9 percent, respectively.
2. Exclusion Technologies
As discussed in chapter 6 of the TDD, screens and other technologies operate using a
principle of excluding organisms from entering the cooling system. For technologies
other than cooling towers, EPA generally calculated their efficacy as the mean percent
efficacy of the available data. Because EPA has sufficient data to evaluate impingement
mortality, its impingement mortality technology efficacy calculation account for
mortality. However, because EPA has data on entrainment exclusion but lack sufficient
entrainment mortality data to calculate exclusion technology entrainment mortality
efficacy, EPA's calculated mean entrainment percent efficacy does not account for
mortality. In reality, whether or not an organism is excluded from the cooling water
intake does not minimize entrainment-related environmental impacts unless the excluded
organisms survive and ultimately are returned back to the waterbody. Available data on
the proposed technology basis demonstrate that entrainment reductions associated with
fine mesh technologies vary depending on life stage and mesh size.
In the 2004 Phase II rule, EPA made the assumption that any entrained organism
entrained died (i.e., 100 percent mortality for organisms passing through the facility) and
any organism not entrained survived. In other words, if a technology reduced
entrainment by 60 percent, then EPA estimated 40 percent of the organisms present in the
intake water would die in comparison to 100 percent in the absence of any entrainment
reduction. As explained in Section VI, EPA has not received any new data on this issue
and, as such, has not altered its conclusion that entrainment leads to 100 percent
mortality.
EPA analyzed the limited data on the survivability of organisms that are "converted"
from entrained to impinged on fine mesh screens. These data show that under most
operational conditions, many, if not all, larvae may die as a result of the impact on fine
mesh screens. In the case of eggs, the data indicate that some species may die, but many
survive. The data also demonstrate that if the organisms can withstand impingement on
the fine mesh screen, the majority survive after passing through a fish return and
returning to the source water. EPA requests additional data on the survivability (or
mortality) of organisms that are converted from entrained to impinged on fish mesh
screens.
21 As discussed in Section VLB of the preamble, impingement mortality and entrainment reductions are
proportional to flow reductions.
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Chapter 2: Summary of Data Collection § 316(b) Existing Facilities Proposed Rule - TDD
2. Compliance Cost Methodology
To assess the economic impact of various regulatory control options, EPA estimates the
costs associated with regulatory compliance. These costs of compliance may include
initial fixed and capital costs, annual operating and maintenance costs, downtime costs,
recordkeeping, monitoring, studies, and reporting costs. The costs estimates reflect the
incremental costs attributed only to the proposed Existing Facilities rule.
For the purposes of estimating incremental compliance costs attributable to regulatory
requirements, EPA traditionally develops either facility-specific or model facility costs.
Facility-specific compliance costs require detailed process information, including
production, capacity, water use, overall management, monitoring data, geographic
location, financial conditions, and other industry specific data for each facility. When
facility-specific data are not available, EPA develops model facilities to provide a
reasonable representation of the industry.
As discussed in the preamble and the TDD, model facility costs were developed for
facilities that completed a detailed industry questionnaire (and therefore the facilities for
which EPA had the best and most detailed information) and national costs were estimated
by multiplying model facility costs by a weighting factor.
EPA has also adopted a new methodology for estimating costs for retrofitting to closed-
cycle cooling. EPRI developed a cost model that incorporates facility-specific data and
reflects state-of-the-art cooling tower design. This model was based on a number of site-
specific engineering design studies at facilities across the U.S. and incorporates a wide
variety of site conditions and facility characteristics. The model is also capable of
incorporating design features such as plume abatement.
EPA also made other changes to its costing assumptions and approaches. For a summary
discussion of these revisions, see the preamble and Chapter 8 of the TDD.
3. Case Studies (Environmental Impacts, Thermal Impacts)
a. Review of NPDES 316(a) and (b) Permits
Addressing Section 316(a) Permit Provisions
The various methods used to address relevant CWA Section 316(s) provisions in permit
limitations for thermal discharges are compared in Exhibit 2-2.22 Of the 103 permits
reviewed, approximately half (53 percent) had some form of effluent temperature
limitations. These were divided between facility permits with some form of an EPA-
approved 316(a) variance (33 percent) and those with temperature limits based on either
State temperature standards or a State-approved model or mixing zone study (20 percent).
22 For a description of the entire analysis, see DCN 10-6623.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 2: Summary of Data Collection
Exhibit 2-2. Methods used to address Section 316(a) Requirements by EPA Region
EPA
Region1
2
3
4
5
6
7
9
10
Total
Permits
8
15
23
20
19
5
5
8
103
None
Given
(Towers
in place)
1
3
1
5
(7%)
(16%)
(20%)
(5%)
Not
Specified
2
3
5
(11%)
(38%)
(5%)
No Temp.
Limits/ No
Monitoring
1
3
5
1
10
(7%)
(13%)
(26%)
(13%)
(10%)
Temp.
Guidance/
Monitoring
Only
2
3
6
10
3
3
1
28
(25%)
(20%)
(26%)
(50%)
(16%)
(60%)
(13%)
(27%)
Application of
State Temp.
Limits/ Mixing
Zone (No
316(a) Req.)
3
2
4
3
6
1
2
21
(38%)
(13%)
(17%)
(15%)
(32%)
(20%)
(25%)
(20%)
316(a)
Variance
Study
3
8
10
7
1
4
1
34
(38%)
(53%)
(43%)
(35%)
(20%)
(80%)
(13%)
(33%)
1 No permits from Regions 1 or 8 were included in the permit review
For the 47 percent of the facilities with no temperature limits in their permit;
approximately 27 percent had temperature monitoring and reporting requirements. The
remaining 20 percent of the facilities had no permit-based temperature limitations (this
included 5 percent with existing cooling towers).
Of the 34 permits with approved 316(a) variances, 17 were approved with historic
evaluation studies that were typically 15-25 years old or of indeterminate vintage
(i.e., insufficient evidence to date effort), with two of these scheduled for a re-evaluation
during the next permit cycle. For 10 of the 13 permits with historic variance studies, the
regional PQR material indicated that documentation of the study was not available as part
of the permit package. Seventeen facilities had updated 316(a) studies that had been
completed within the last five years.
A comparison was made of the Section 316(a) permit provisions between electrical
power generating plants and manufacturers nationwide. The large majority (77 percent)
of the twenty-two manufacturing facilities had either no effluent temperature limitations
or monitoring and reporting requirements. None of manufacturers had an approved
316(a) variance study whereas 42 percent of the power plants did.
Addressing Section 316(b) Permit Provisions
The various methods used to address relevant Section 316(b) provisions in permit
limitations are compared in Exhibit 2-3. A breakdown of the compliance categories
indicates that 51 percent of the facilities' permit conditions contained little or no
references to 316(b) regulations. Further analysis of the 316(b) provision status
nationwide indicates that none of the manufacturing facilities had 316(b) requirements
specified in their permits, while 36 percent of the generators had none.
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Chapter 2: Summary of Data Collection
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 2-3. Methods used to address Section 316(b) Requirements by EPA Region
EPA
Region
2
3
4
5
6
7
9
10
Total
Permits
8
15
23
20
19
5
5
8
103
Not
Specified
4
3
15
5
13
2
8
50
(50%)
(20%)
(65%)
(25%)
(68%)
(40%)
(100%)
(49%)
None
2
2
(11%)
(2%)
CDS, not
initiated
1
4
2
3
3
4
17
(13%)
(27%)
(9%)
(15%)
(60%)
(80%)
(17%)
CDS,
ongoing
3
4
2
9
(20%)
(20%)
(11%)
(9%)
Approved permit
conditions
Historic
Evaluations
1
3
4
8
(7%)
(13%)
(20%)
(8%)
Current
Re-
evaluation
3
2
4
2
11
(38%)
(9%)
(20%)
(11%)
(11%)
New
Facility
(subject
to
Phase I)
2
2
(13%)
(2%)
None
Given
(Tower
in place)
2
1
1
4
(13%)
(4%)
(20%)
(4%)
Approximately 19 percent of the facilities had an approved 316(b) demonstration; which
included 11 percent that were scheduled for a re-evaluation during the next permit cycle.
Nine percent of the facilities reportedly had initiated a CDS investigation while 17
percent were required to conduct the CDS within the current 5-year permit cycle but had
not started at the time of permit issuance. The current status of these CDS activities is
uncertain due to the remand of the Phase II facility 316(b) regulations in midst of the
current permit cycle. Specifically, on July 9, 2007 (72 FR 37107), EPA suspended the
bulk of the Phase II 316(b) regulation and announced that, pending further rulemaking
(currently ongoing), permit requirements for cooling water intake structures at Phase II
facilities should be established on a case-by-case, best professional judgment (BPJ) basis.
Of the 103 facilities reviewed, eleven facilities had cooling towers already installed with
an additional six facilities in the process of installing cooling towers.
Overview of New or Revised Analyses
A review of 103 NPDES permits, together with corresponding factsheets and relevant
EPA PQR documents, identified permit effluent limitations and/or operating conditions
pertaining to how generation and manufacturing facilities dealt with potential Sections
316(a) and 316(b) permit provisions. Based on this review:
• Of the permits reviewed, 53 percent had effluent temperature limitations either
based on EPA-approved 316(a) variance (33 percent of all facilities) or state-
approved models or mixing zone studies (20 percent). The remaining facilities
either had no temperature limits (20 percent) or monitoring only (27 percent):
• For facilities with approved 316(a) variances, about half were based on historic
studies or required re-evaluation the following permit cycle, while half were
based on updated 316(a) studies conducted within the last five years;
• Permit temperature limitations for maximum temperature varied widely between
states and environmental settings. Permit limits for allowable deviation from
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 2: Summary of Data Collection
ambient conditions generally adhered to States water quality temperature
standards;
• Over half (51 percent) of the NPDES permits reviewed did not contain any
reference to Section 316(b) requirements. However, inclusion of 316(b)
compliance requirements varied widely between permits for manufacturing
facilities (0 percent included 316(b) requirements) and generators (64 percent);
and
• Cooling towers were installed in 11 or scheduled to be installed at six of the 103
or 16 percent of all facilities considered.
4. Closed-cycle Cooling
EPA considered a wide variety of technical aspects associated with retrofitting cooling
towers, including (but not limited to) the availability of land, noise and plume effects,
evaporative losses, and nuclear safety concerns.
As discussed in Chapter 10 of the TDD, EPA had previously conducted analyses for
these effects; Chapter 10 provides the updated analyses.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 3: Scope/Applicability
Chapter 3: Scope/Applicability of Proposed Rule
3.0 Introduction
The proposed Existing Facilities rule includes all existing facilities that were previously
subject to the 2004 Phase II and 2006 Phase III rules, including existing power producers
and manufacturers with a design intake flow of more than 2 MGD that withdraw at least
25 percent of water for cooling purposes. The proposed rule also clarifies the definition
and requirements for new units at existing facilities. The applicable requirements are
summarized in Exhibits 3-1 and 3-2.
Exhibit 3-1. Applicability by Phase of the 316(b) Rules
Facility Characteristic
New power generating or manufacturing facility
New offshore oil and gas facility
New unit at an existing power generating or
manufacturing facility
Existing power generating or manufacturing facility
Existing offshore oil and gas facility, seafood
processing vessel or LNG import terminal
Applicable Rule
Phase 1 rule
Phase III rule
This proposed rule
This proposed rule
Case-by-case, Best professional judgment
Exhibit 3-2. Applicable Requirements of the Proposed Rule for Existing Facilities
Facility Characteristic
Existing facility with a DIP >125 MGD
Existing facility with a DIP >2 MGD
New unit at an existing facility
Facility with a cooling water intake structure that does
not meet the criteria in 125.91
Applicable Requirements
Impingement mortality requirements at 125.94(c) and
Entrainment Characterization Study requirements at
125.94(b)
Impingement mortality requirements at 125.94(c) (no
entrainment requirements)
Impingement mortality requirements at 125.94(c) and
Entrainment Characterization Study requirements at
125.94(b)
Case-by-case, Best professional judgment
Initially, EPA divided the 316(b) rulemaking into three phases; however, as EPA's
analysis progressed, it became clear that cooling water intake structures are operated
similarly at most industrial facilities (i.e., both power producing and manufacturing
facilities). From a biological perspective, the effect of intake structures on impingement
and entrainment does not differ depending on whether an intake structure is associated with
a power plant or a manufacturer. Instead the impingement and entrainment impacts
associated with intakes of the same type are generally comparable, and these impacts are
addressed without discriminating which facilities are behind the intake structure. Thus,
EPA is consolidating the universe of potentially regulated facilities from the 2004 Phase II
rule with the existing facilities in the 2006 Phase III rule for purposes of the proposed
Existing Facilities rule. This consolidation also provides a "one-stop shop" for information
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Chapter 3: Scope/Applicability § 316(b) Existing Facilities Proposed Rule - TDD
related to the proposed rulemaking, as all existing facilities would be addressed in an
equitable manner by the same set of technology-based requirements.
3.1 General Applicability
This rule would apply to owners and operators of existing facilities that meet all of the
following criteria:
• The facility is a point source that uses or proposes to use one or more cooling water
intake structures, including a cooling water intake structure operated by an
independent supplier that withdraws water from waters of the United States and
provides cooling water to the facility by any sort of contract or other arrangement;
• The total design intake flow of the cooling water intake structure(s) is more than
2 MOD; and
• The cooling water intake structure(s) withdraw(s) cooling water from waters of the
United States and at least twenty-five (25) percent of the water withdrawn is used
exclusively for cooling purposes measured on an average annual basis for each
calendar year.
EPA is proposing to continue to adopt provisions to ensure that the rule does not
discourage the reuse of cooling water for other uses such as process water. The definition
of cooling water at 40 CFR 125.93 provides that cooling water used in a manufacturing
process either before or after it is used for cooling is considered process water for the
purposes of calculating the percentage of a facility's intake flow that is used for cooling
purposes. Therefore, water used for both cooling and non-cooling purposes does not count
towards the 25 percent threshold. EPA notes this definition is the same definition used for
new facilities in the Phase I rule at 40 CFR 125.83. Examples of water withdrawn for
non-cooling purposes includes water withdrawn for warming by liquefied natural gas
facilities and water withdrawn for public water systems by desalinization facilities.
Further, the proposed rule at 40 CFR 125.91(c) specifies that cooling water obtained from a
public water system or using treated effluent (such as wastewater treatment plant "gray"
water) as cooling water does not constitute use of a cooling water intake structure for
purposes of this rule.
The proposed Existing Facilities rule focuses on those facilities that are significant users of
cooling water; only those facilities that use more than 25 percent of the water withdrawn
for cooling purposes are subject to requirements. Using 25 percent as the threshold for the
percent of flow used for cooling purposes at power plants ensures that almost all cooling
water withdrawn from waters of the U.S. is addressed by requirements for minimizing
adverse environmental impact. While manufacturing facilities often withdraw water for
more than cooling purposes, the majority of the water is withdrawn from a single intake
structure.l Once water passes through the intake, water can be apportioned to any desired
use, including uses that are not related to cooling. Similarly, because power generating
facilities typically use far more than 25 percent of the water they withdraw for cooling
1 Facilities may also use groundwater wells or municipal water for various uses, but the volume of these
withdrawals is usually much smaller than the volume withdrawn from surface waters.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 3: Scope/Applicability
purposes, EPA proposes to establish the 25 percent threshold to ensure that nearly all
cooling water and the largest existing facilities using cooling water intake structures are
addressed by the proposed requirements. As a result, EPA estimates that approximately 68
percent of manufacturers and 93 percent of power-generating facilities that meet the other
proposed thresholds for the rule use more than 25 percent of intake water for cooling.
EPA is proposing that the Director, using BPJ, establish BTA impingement and
entrainment mortality standards for an existing offshore oil and gas facility, a seafood
processing vessel, or an offshore liquefied natural gas import terminal. Such a facility
would be subject to permit conditions implementing CWA Section 316(b) where the
facility is a point source that uses a cooling water intake structure and has, or is required to
have, an NPDES permit. Permit writers may further determine that an intake structure that
withdraws less than 25 percent of the intake flow for cooling purposes should be subject to
Section 316(b) requirements, and set appropriate requirements on a case-by-case basis,
using best professional judgment. The proposed Existing Facilities rule is not intended to
constrain permit writers, including those at the Federal, State, or Tribal level, from
addressing such cooling water intake structures. EPA also recognizes that facilities may
reuse water within their facility; any volume of cooling water that is reused may be
subtracted from the total withdrawal of cooling water by the facility when determining if a
facility is subject to the proposed rule.
3.1.1 What is an "Existing Facility" for Purposes of the Section 316(b)
Existing Facility Rule?
In the proposed Existing Facilities rule, EPA is defining the term "existing facility" to
include any facility that commenced construction before January 18, 2002, as provided for
in 40 CFR 122.29(b)(4).2 EPA is proposing to establish January 17, 2002 as the date for
distinguishing existing facilities from new facilities because that is the effective date of the
Phase I new facility rule. In addition, EPA is defining the term "existing facility" in this
proposed rule to include modifications and additions to such facilities, the construction of
which commences after January 17, 2002, that do not meet the definition of a new facility
at 40 CFR 125.83, the definition used to define the scope of the Phase I rule. That
definition states:
"New facility means any building, structure, facility, or installation that meets the
definition of a 'new source' or 'new discharger' in [other NPDES regulations] and
is a greenfield or stand-alone facility; commences construction after January 17,
2002; and uses either a newly constructed cooling water intake structure, or an
existing cooling water intake structure whose design capacity is increased to
accommodate the intake of additional cooling water. New facilities include only
'greenfield' and 'stand-alone' facilities. A greenfield facility is a facility that is
constructed at a site at which no other source is located or that totally replaces the
process or production equipment at an existing facility (see 40 CFR 122.29(b)(l)(i)
and (ii). A stand-alone facility is a new, separate facility that is constructed on
2 Construction is commenced if the owner or operator has undertaken certain installation and site preparation
activities that are part of a continuous on-site construction program, and it includes entering into certain
specified binding contractual obligations as one criterion (40 CFR 122.29(b)(4)).
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Chapter 3: Scope/Applicability § 316(b) Existing Facilities Proposed Rule - TDD
property where an existing facility is located and whose processes are substantially
independent of the existing facility at the same site (see 40 CFR 122.29(b)(l)(iii)
and are not used for the same industrial purpose. New facility does not include new
units that are added to a facility for purposes of the same general industrial
operation (for example, a new peaking unit at an electrical generating station)."3
The preamble to the final Phase I rule discusses this definition at 66 FR 65256; 65258 -
65259; 65285 - 65287, December 18, 2001. EPA's definition of an "existing facility" in
the proposed Existing Facilities rule is intended to ensure that all sources excluded from
the definition of new facility in the Phase I rule are captured by the proposed definition of
existing facility.
A point source would be subject to Phase I or the proposed Existing Facilities rule even if
the cooling water intake structure it uses is not located at the facility.4 In addition,
modifications or additions to the cooling water intake structure (or even the total
replacement of an existing cooling water intake structure with a new one) do not convert an
otherwise unchanged existing facility into a new facility, regardless of the purpose of such
changes (e.g., to comply with the proposed rule or to increase capacity). Rather, the
determination as to whether a facility is new or existing focuses on whether it is a green
field or stand-alone facility and whether there are changes to the cooling water intake to
accommodate it.
3.1.2 What is "Cooling Water" and What is a "Cooling Water Intake
Structure?"
EPA has not revised the definition of cooling water intake structure for the proposed
Existing Facilities rule. A cooling water intake structure is defined as the total physical
3 The Phase I rule also listed examples of facilities that would be "new" facilities and facilities that would
"not be considered a 'new facility' in two numbered paragraphs. These read as follows:
"(1) Examples of 'new facilities' include, but are not limited to: the following scenarios:
(i) A new facility is constructed on a site that has never been used for industrial or commercial activity. It has
a new cooling water intake structure for its own use.
(ii) A facility is demolished and another facility is constructed in its place. The newly-constructed facility
uses the original facility's cooling water intake structure, but modifies it to increase the design capacity to
accommodate the intake of additional cooling water.
(iii) A facility is constructed on the same property as an existing facility, but is a separate and independent
industrial operation. The cooling water intake structure used by the original facility is modified by
constructing a new intake bay for the use of the newly constructed facility or is otherwise modified to
increase the intake capacity for the new facility.
(2) Examples of facilities that would not be considered a 'new facility' include, but are not limited to, the
following scenarios:
(i) A facility in commercial or industrial operation is modified and either continues to use its original cooling
water intake structure or uses a new or modified cooling water intake structure.
(ii) A facility has an existing intake structure. Another facility (a separate and independent industrial
operation), is constructed on the same property and connects to the facility's cooling water intake structure
behind the intake pumps, and the design capacity of the cooling water intake structure has not been increased.
This facility would not be considered a 'new facility' even if routine maintenance or repairs that do not
increase the design capacity were performed on the intake structure."
4 For example, a facility might purchase its cooling water from a nearby facility that owns and operates a
cooling water intake structure.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 3: Scope/Applicability
structure and any associated constructed waterways used to withdraw cooling water from
waters of the United States. Under the definition in the proposed Existing Facilities rule,
the cooling water intake structure extends from the point at which water is withdrawn from
the surface water source up to, and including, the intake pumps. The proposed Existing
Facilities rule puts forth for existing facilities the same definition of a "cooling water intake
structure" that applies to new facilities under Phase I. The proposed Existing Facilities rule
also adopts the new facility rule's definition of "cooling water" as water used for contact or
noncontact cooling, including water used for equipment cooling, evaporative cooling
tower makeup, and dilution of effluent heat content. The definition specifies that the
intended use of cooling water is to absorb waste heat rejected from the processes used or
auxiliary operations on the facility's premises. The definition also indicates that water
used in a manufacturing process either before or after it is used for cooling is process water
for both cooling and non-cooling purposes and would not be considered cooling water for
purposes of determining whether 25 percent or more of the flow is cooling water. This
clarification is necessary because cooling water intake structures typically bring water into
a facility for numerous purposes, including industrial processes; use as circulating water,
service water, or evaporative cooling tower makeup water; dilution of effluent heat
content; equipment cooling; and air conditioning. EPA notes that this clarification does
not change the fact that only the intake water used exclusively for cooling purposes is
counted when determining whether the 25 percent threshold in 40 CFR 125.91(a)(3)ismet.
3.1.3 Would My Facility Be Covered if it is a Point Source Discharger?
The proposed Existing Facilities rule would apply only to facilities that are point sources
(i.e., have an NPDES permit or are required to obtain one). This is the same requirement
EPA included in the Phase I new facility rule at 40 CFR 125.81(a)(l). Requirements for
complying with Section 316(b) will continue to be applied through NPDES permits.
Based on the Agency's review of potential existing facilities that employ cooling water
intake structures, the Agency anticipates that most existing facilities subject to the
proposed Existing Facilities rule will control the intake structure that supplies them with
cooling water, and discharge some combination of their cooling water, wastewater, or
storm water to a water of the United States through a point source regulated by an NPDES
permit. Under these circumstances, the facility's NPDES permit will include the
requirements for the cooling water intake structure. In the event that an existing facility's
only NPDES permit is a general permit for storm water discharges, the Agency anticipates
that the Director would write an individual NPDES permit containing requirements for the
facility's cooling water intake structure. Alternatively, requirements applicable to cooling
water intake structures could be incorporated into general permits. If requirements are
placed into a general permit, they must meet the requirements set out at 40 CFR 122.28.
As EPA stated in the preamble to the final Phase I rule (66 FR 65256 (December 18,
2001)), the Agency encourages the Director to closely examine scenarios in which a
facility withdraws significant amounts of cooling water from waters of the United States
but is not required to obtain an NPDES permit. As appropriate, the Director will
necessarily apply other legal requirements, where applicable, such as Section 404 or 401 of
the Clean Water Act, the Coastal Zone Management Act, the National Environmental
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Chapter 3: Scope/Applicability § 316(b) Existing Facilities Proposed Rule - TDD
Policy Act, the Endangered Species Act, or similar State or Tribal authorities to address
adverse environmental impact caused by cooling water intake structures at those facilities.
3.1.4 Would My Facility Be Covered if it Withdraws Water From Waters
of the U.S.? What if My Facility Obtains Cooling Water from an
Independent Supplier?
The requirements in the proposed Existing Facilities rule apply to cooling water intake
structures that have the design capacity to withdraw amounts of water more than 2 MGD
from "waters of the United States." Waters of the United States include the broad range of
surface waters that meet the regulatory definition at 40 CFR 122.2, which includes lakes,
ponds, reservoirs, nontidal rivers or streams, tidal rivers, estuaries, fjords, oceans, bays,
and coves. These potential sources of cooling water may be adversely affected by
impingement and entrainment.
Some facilities discharge heated water to manmade cooling ponds, and then withdraw
water from the ponds for cooling purposes. EPA recognizes that cooling ponds may, in
certain circumstances, constitute a closed-cycle cooling system and therefore may already
comply with some or all of the technology-based requirements in the proposed rule.
However, facilities that withdraw cooling water from cooling ponds that are waters of the
United States and that meet the other criteria for coverage (including the requirement that
the facility has or will be required to obtain an NPDES permit) would be subject to the
proposed Existing Facilities rule. In some cases, water is withdrawn from a water of the
United States to provide make-up water for a cooling pond. In many cases, EPA expects
such make-up water withdrawals are commensurate with the flows of a closed-cycle
cooling tower, and again the facility may already comply with requirements to reduce its
intake flow under the proposed rule. In those cases where the withdrawals of make-up
water come from a waters of the United States, and the facility otherwise meets the criteria
for coverage (including a design intake flow of more than 2 million gallons per day), the
facility would be subject to the proposed Existing Facilities rule requirements.
EPA does not intend this rule to change the regulatory status of cooling ponds. Cooling
ponds are neither categorically included nor categorically excluded from the definition of
"waters of the United States" at 40 CFR 122.2. EPA interprets 40 CFR 122.2 to give
permitting authorities the discretion to regulate cooling ponds as "waters of the United
States" where cooling ponds meet the definition of "waters of the United States." The
determination whether a particular cooling pond is, or is not, a water of the United States is
to be made by the permitting authority on a case-by-case basis. The EPA and the
U.S. Army Corps of Engineers have jointly issued jurisdictional guidance concerning the
term "waters of the United States" in light of the Supreme Court's decision in Solid Waste
Agency of Northern Cook County v. U.S. Army Corps of Engineers., 531 U.S. 159 (2001)
(SWANCC). A copy of that guidance was published as an Appendix to an Advanced
Notice of Proposed Rulemaking on the definition of the phrase "waters of the U.S.," see 68
FR 1991 (January 15, 2003), and may be obtained at
(http://www.epa.gov/owow/wetlands/pdf/ANPRM-FR.pdf).
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 3: Scope/Applicability
The Agency recognizes that some facilities that have or are required to have an NPDES
permit might not own and operate the intake structure that supplies their facility with
cooling water. In addressing facilities that have or are required to have an NPDES permit
that do not directly control the intake structure that supplies their facility with cooling
water, revised 40 CFR 125.91 provides (similar to the new facility rule) that facilities that
obtain cooling water from a public water system or use treated effluent are not deemed to
be using a cooling water intake structure for purposes of the proposed Existing Facilities
rule. However, obtaining water from another entity that is withdrawing water from a water
of the US would be counted as cooling water intake water for purposes of determining
whether an entity meets the threshold requirements of the rule. For example, facilities
operated by separate entities might be located on the same, adjacent, or nearby
property(ies); one of these facilities might take in cooling water and then transfer it to other
facilities prior to discharge of the cooling water to a water of the United States. 40 CFR
125.91(b) specifies that use of a cooling water intake structure includes obtaining cooling
water by any sort of contract or arrangement with one or more independent suppliers of
cooling water if the supplier or suppliers withdraw water from waters of the United States
but that is not itself an existing facility subject to Section 316(b).
As a practical matter, existing facilities are the largest users of cooling water, and typically
require enough cooling water to warrant owning the cooling water intake structures. In
some cases, such as at nuclear power plants or critical baseload facilities, the need for
cooling water includes safety and reliability reasons would likely preclude any
independent supplier arrangements. Therefore, EPA does not expect much application of
this provision. EPA is nevertheless retaining the provision in order to prevent facilities
from circumventing the requirements of the proposed Existing Facilities rule by creating
arrangements to receive cooling water from an entity that is not itself subject to the
proposed rule, and is not exempt from the proposed rule (such as drinking water or
treatment plant discharges reused as cooling water).
3.1.5 What Intake Flow Thresholds Result in an Existing Facility Being
Subject to the Proposed Existing Facilities Rule?
There are two ways in which EPA determines the cooling water flow at a facility. The first
way is based on the design intake flow (DIP), which reflects the maximum intake flow the
facility is capable of withdrawing. While this normally is limited by the capacity of the
cooling water intake pumps, other parts of the cooling water intake system could impose
physical limitations on the maximum intake flow the facility is capable of withdrawing.
The second way is based on the actual intake flow (AIF), which reflects the actual volume
of water withdrawn by the facility. EPA has defined AIF to be the average water
withdrawn each year over the preceding 3 years. Both of these definitions are in the
proposed Existing Facilities rule.
EPA considered requirements based on the intake flow at the existing facility. The
proposed Existing Facilities rule applies to facilities that have a total design intake capacity
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Chapter 3: Scope/Applicability § 316(b) Existing Facilities Proposed Rule - TDD
of more than 2 MOD (see 40 CFR 125.91).5 At 2 MOD, 99.7 percent of the total water
withdrawals would be covered while 58 percent of the manufacturers, 70 percent of the
non-utilities, and 100 percent of the utilities would be covered. EPA also chose the 2 MOD
threshold to be consistent with the applicability criteria in the Phase I rule.6 EPA continues
to believe that this threshold ensures that the largest users of cooling water will be subject
to the proposed rule.
EPA proposes to continue to use a threshold based on design intake flow as opposed to
actual intake flow for several reasons. In contrast to actual intake flow, design intake flow
is a fixed value based on the design of the facility's operating system and the capacity of
the circulating and other water intake pumps. This provides clarity, as the design intake
flow does not change, except in limited circumstances, such as when a facility undergoes
major modifications. On the other hand, actual flows can vary significantly over
sometimes short periods of time. For example, a peaking power plant may have an actual
intake flow close to the design intake flow during times of full energy production, and may
be zero during periods of standby. Use of design intake flow provides clarity to regulatory
status, is indicative of the possible magnitude of environmental impact, and would avoid
the need for monitoring to confirm a facility's status. Also see 69 FR 41611 for more
information about these thresholds.
Under current NPDES permitting regulations at 40 CFR 122.21, all existing facilities
greater than 2 MOD DIF must submit basic information describing the facility, source
water physical data, source water biological characterization data, and cooling water intake
system data. Under the proposed Existing Facilities rule, all facilities greater than 2 MGD
DIF would be required to submit additional facility-specific information including the
proposed impingement mortality reduction plan, relevant biological survival studies, and
operational status of each of the facility's units. Certain facilities withdrawing the largest
volumes of water for cooling purposes would have additional information and study
requirements such as the Entrainment Characterization Study as described below.
EPA seeks to clarify that for some facilities, the design intake flow is not necessarily the
maximum flow associated with the intake pumps. For example, a power plant may have
redundant circulating pumps, or may have pumps with a name plate rating that exceeds the
maximum water throughput of the associated piping. EPA intends for the design intake
flow to reflect the maximum volume of water that a plant can physically withdraw from a
source waterbody over a specific time period. This also means that a plant that has
permanently taken a pump out of service or has flow limited by piping or other physical
limitations should be able to consider such constraints when reporting its DIF.
5 The 2004 Phase II rule applied to existing power-generating facilities with a design intake flow of 50 MGD
or greater. Facilities potentially in scope of the Phase III rule had a DIF of greater than 2 MGD.
6 See 65 FR 49067/3 for more information.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 3: Scope/Applicability
3.1.6 Are Offshore Oil and Gas Facilities, Seafood Processing Vessels
or LNG Import Terminals Addressed Under the Proposed
Existing Facilities Rule?
Under the proposed Existing Facilities rule, existing offshore oil and gas facilities, seafood
processing facilities and LNG import terminals would be subject to 316(b) requirements on
a best professional judgment basis. In the Phase III rule, EPA studied offshore oil and gas
facilities and seafood processing facilities7 and could not identify any technologies
(beyond the protective screens already in use) that are technically feasible for reducing
o
impingement or entrainment in such existing facilities. As discussed in the Phase III rule,
known technologies that could further reduce impingement or entrainment would result in
unacceptable changes in the envelope of existing platforms, drilling rigs, mobile offshore
drilling units (MODUs), seafood processing vessels (SPVs), and similar facilities as the
technologies would project out from the hull, potentially decrease the seaworthiness, and
potentially interfere with structural components of the hull. EPA also believes that for
many of these facilities, the cooling water withdrawals are most substantial when the
facilities are operating far out at sea - and therefore not withdrawing from a water of the
U.S. The EPA is aware that LNG facilities may withdraw hundreds of MGD of seawater
for warming (re-gasification). However, some existing LNG facilities may still withdraw
water where 25 percent or more of the water is used for cooling purposes. As discussed in
section V of the preamble, EPA has not identified a uniformly applicable and available
technology for minimizing impingement and entrainment (I&E) mortality at these
facilities. However, technologies may be available for some existing LNG facilities. LNG
facilities that withdraw any volume of water for cooling purposes would be subject to
case-by-case, best professional judgment BTA determinations.
EPA has not identified any new data or approaches that would result in a different
determination. Therefore, the proposed Existing Facilities rule would continue to require
that the BTA for existing offshore oil and gas extraction facilities and seafood processing
facilities is through conditions established by NPDES permit directors on a case-by-case
basis using best professional judgment.
3.1.7 What is a "New Unit" and How Are New Units Addressed Under
This Proposed Rule?
The Phase I rule did not distinguish between new stand-alone facilities and new units
where the units are built on a site where a source is already located and does not totally
replace the existing source. Because EPA is not changing the new facility rule definitions,
and is only proposing clarifying revisions to the existing facility rule, this proposed
provision is not intended to otherwise reopen the Phase I rule. Today's proposed rule
establishes requirements for new units added to an existing facility that are not a "new
7 EPA studied naval vessels and cruise ships as part of its development of a general NPDES permit for
discharges from ocean-going vessels. (See http://cfpub.epa.gov/npdes/home.cfm7program_id=350 for more
information.) EPA studied seafood processing vessels and oil and gas exploration facilities in the 316(b)
Phase III rule.
8 As discussed in the preamble, requirements for new offshore facilities set forth in the Phase III rule remain
in effect.
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Chapter 3: Scope/Applicability § 316(b) Existing Facilities Proposed Rule - TDD
facility" as defined at 40 CFR 125.83. Today's proposal seeks to clarify the definitions of
"new" versus "existing" by first noting that, for purposes of section 316(b), a facility
cannot be defined as a new facility and an existing facility at the same time. In this rule,
while EPA will continue to treat replacement and new units for the same industrial purpose
as existing facilities, EPA intends to have different requirements for the addition of new
units. A replacement unit or repowered unit, as distinct from constructing an additional
unit, would not be treated as a new unit. The requirements for new units are modeled after
the requirements for a new facility in the Phase I rule.
For a complete discussion of how new units are addressed, refer to section V.H of the
preamble.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
Chapter 4: Industry Description
4.0 Introduction
This chapter presents a profile of the facilities potentially regulated under the proposed
Existing Facilities rule. The proposed rule would apply national requirements to existing
facilities that use cooling water intake structures to withdraw water for cooling from
waters of the U.S. Specifically, the proposed rule would apply to owners and operators
of existing facilities that meet all of the following criteria:
• The facility is a point source that uses or proposes to use one or more cooling
water intake structures, including a cooling water intake structure operated by an
independent supplier that withdraws water from waters of the United States and
provides cooling water to the facility by any sort of contract or other arrangement;
• The total design intake flow of the cooling water intake structure(s) is more than
2 MOD; and
• The cooling water intake structure(s) withdraw(s) cooling water from waters of
the United States and at least twenty-five (25) percent of the water withdrawn is
used exclusively for cooling purposes measured on an average annual basis for
each calendar year.
The proposed Existing Facilities rule would apply to all existing power plants and all
existing manufacturing facilities that meet the above criteria. This chapter presents
information characterizing the categories of facilities subject to the proposed rule.
Much of the information presented in this chapter is based on data from the U.S.
Department of Energy's (DOE) "Annual Electric Generator Report" (Form EIA-860) and
"Annual Electric Power Industry Report" (Form EIA-861), and EPA's Section 316(b)
2000 Industry Surveys (the Industry Short Technical Questionnaire [STQ] and the
Detailed Industry Questionnaire [DQ] for Phase II Cooling Water Intake Structures). For
more information on aspects of the industry that may influence the nature and magnitude
of economic impacts of the proposed Existing Facilities rule, see the Economic and
Benefits Analysis for the Proposed Section 316(b) Existing Facilities Rule (EBA).
The electric power industry and the other industries subject to the proposed Existing
Facilities rule are studied extensively by many organizations and government agencies.
DOE's Energy Information Administration (EIA), among others, publishes a multitude of
reports, documents, and studies on an annual basis. This chapter profile is not intended to
duplicate those efforts. Rather, this profile compiles, summarizes, and presents those
industry data that are important in the context of the technical analysis for the proposed
Existing Facilities rule. For more information on general concepts, trends, and
developments in the electric power industry and other industries affected by the proposal,
see the "References," section of this chapter.
EPA first described the electricity industry in its April 2002 Phase II Proposed Rule (see
67 FR 17135-17136). A profile of other industries and existing manufacturers was
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
developed to support the proposed Phase III Rule (see Phase III Proposed Rule TDD;
EPA-821-R-04-015, DCN 7-0004 in the Phase III docket, available at EPA-HQ-OW-
2004-0002-0025 to -0029). While these general descriptions still apply, EPA has updated
some of its earlier estimates to reflect a more current and comprehensive industry profile
for facilities subject to the proposed Existing Facilities rule.
The glossary located at the end of this chapter provides definitions for all terms that are
bolded and italicized throughout this chapter.
4.1 Industry Overview
This section provides a brief overview of the industry, including descriptions of major
industry sectors and types of generating facilities.
4.1.1 Major Industry Sectors
In 1997, EPA estimated that over 400,000 facilities could potentially be subject to a
cooling water intake regulation. Given the large number of facilities potentially subject
to regulation, EPA decided to focus its data collection efforts on six industrial categories
that, as a whole, are estimated to account for over 99 percent of all cooling water
withdrawals. These six sectors are: Utility Steam Electric, Nonutility Steam Electric,
Chemicals & Allied Products, Primary Metals Industries, Petroleum & Coal Products,
and Paper & Allied Products. EPA's data collection efforts (via the 1998 industry
questionnaire) focused on the electric generators (both utility and nonutility steam
electric) and the four manufacturing industry groups that were identified as significant
users of cooling water. These industries are presented below, as described by the
Standard Industrial Classification (SIC) system, and are intended to represent all electric
generators and manufacturers with a DIP greater than 2 MGD.
Electric Services
This industry sector is classified under SIC Major Group 49. This major group includes
establishments engaged in the generation., transmission., and/or distribution of electricity
or gas or steam. A detailed discussion of the electricity industry is provided in section
4.2 of this chapter.
Chemical and Allied Products
This industry sector is classified under SIC Major Group 28. This major group includes
establishments producing basic chemicals and establishments manufacturing products by
predominantly chemical processes. Establishments classified in this major group
manufacture three general classes of products: (1) basic chemicals, such as acids,
alkalies, salts, and organic chemicals; (2) chemical products to be used in further
manufacture, such as synthetic fibers, plastics materials, dry colors, and pigments; and
(3) finished chemical products to be used for ultimate consumption, such as drugs,
cosmetics, and soaps; or to be used as materials or supplies in other industries, such as
paints, fertilizers, and explosives.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
Primary Metals Industries
This industry sector is classified under SIC Major Group 33. This major group includes
establishments engaged in smelting and refining ferrous and nonferrous metals from ore,
pig, or scrap; in rolling, drawing, and alloying metals; in manufacturing castings and
other basic metal products; and in manufacturing nails, spikes, and insulated wire and
cable.
Paper and Allied Products
This industry sector is classified under SIC Major Group 26. This major group includes
establishments primarily engaged in the manufacture of pulps from wood and other
cellulose fibers, the manufacture of paper and paperboard, and the manufacture of paper
and paperboard into converted products.
Petroleum and Coal Products
This industry sector is classified under SIC Major Group 29. This major group includes
establishments primarily engaged in petroleum refining, manufacturing paving and
roofing materials, and compounding lubricating oils and greases from purchased
materials.
Other Industries
EPA sent industry questionnaires to individual facilities from a number of other
industries outside of the four listed above and incorporated that data into the analysis for
the proposed Existing Facilities rule. In 2004, EPA also collected information on land-
based liquefied natural gas (LNG) facilities.
The following sections describe the electricity industry and the other manufacturing
sectors and describe how cooling water is withdrawn and used at these facilities. In many
cases, the facility data has been aggregated into two major groups; Electric Generators
(Electric Services) and Manufacturing Facilities. The Manufacturing Facilities group
includes all industrial facilities described above that are not classified as Electric
Generators (i.e., Chemical and Allied Products, Primary Metals Industries, Paper and
Allied Products, Petroleum and Coal Products, and Other Industries).
4.1.2 Number of Facilities and Design Intake Flow Characteristics
EPA estimates that approximately 1,263 facilities in the major industrial categories would
be subject to regulation under the proposed Existing Facilities rule. These facilities
combine to account for a design intake flow of over 409 billion gallons per day of cooling
water from approximately 1,836 cooling water intake structures. While electric
generators account for just over 53 percent of the number of facilities, they account for
approximately 90 percent of the total estimated design intake flow. See Exhibit 4-1
below.
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-1. Cooling Water Use in Surveyed Industries
Facilities Potentially Regulated
Under Proposed Existing
Facilities Rule (all existing
facilities that withdraw more than
2MGD)
Existing electric generators
Existing manufacturers
Estimated
Number of
Facilities
1,263
671
592
Percent of
Total Number
of Facilities
100
53
47
Estimated Total
Design Intake
Flow (MGD)
409,600
370,126
39,473
Percent of
Total Design
Intake Flow
100
90
10
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include facilities identified as baseline closures. Design intake flow for Short Technical
Survey Facilities was imputed from average intake flow.
Exhibit 4-2 shows the geographic distribution of the estimated facilities subject to 316(b).
For illustrative purposes, manufacturers and electric generators are separated; generators
are further separated by the former designations of Phase II and Phase III facilities, which
is no longer relevant.
Exhibit 4-2. Map of Facilities Subject to 316(b)
316(b) Facilities
Legend
Manufacturer
Phase 3 Generator
Phase 2 Generator
Exhibit 4-3 illustrates the range and distribution of the number of facilities by design
intake flows (DIP).
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-3. Distribution of Facilities by Design Intake Flows
Design Intake
Flow (MGD)
2-10
10-20
20-50
50-100
100-200
200 - 500
500-1,000
>1,000
Total
Electric Generators
Estimated
Number of
Facilities
37
29
51
56
90
152
145
112
671
Percent of
Number of
Facilities
5
4
8
8
13
23
22
17
100
Manufacturers
Estimated
Number of
Facilities
139
95
196
84
44
23
7
3
592
Percent of Number
of Facilities
24
16
33
14
7
4
1
0.5
100
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include those facilities identified as baseline closures. Design intake flow for Short
Technical Survey Facilities was imputed from average intake flow.
Exhibit 4-3 shows that the majority of electric generator facilities have a DIF >100 MGD
while the majority of manufacturers have a DIP in the 2 to 50 MGD range.
Exhibit 4-4 shows the estimated total DIP and average intake flow (AIF) for each flow
range shown in Exhibit 4-2. The percent AIF/DIF shows the relative volume of AIF to
DIF for each flow range.
Exhibit 4-4. Relative Volumes of Design Intake Flow and Average Intake Flow
Design Intake Flow
(MGD)
2-10
10-20
20-50
50-100
100-200
200 - 500
500-1,000
>1,000
Total
Electric Generators
Total weighted
DIF MGD
178
449
1,745
4,087
12,464
49,946
103,672
197,586
370,126
Total
weighted AIF
MGD
71
175
830
2,010
6,042
26,501
61,995
118,970
216,593
Percent
AIF/DIF
40%
39%
48%
49%
48%
53%
60%
60%
59%
Manufacturers
Total
weighted
DIF MGD
719
1,322
6,217
5,887
6,355
7,883
4,606
6,484
39,473
Total
weighted
AIF MGD
321
667
3,158
3,341
3,043
4,247
2,767
3,696
21,239
Percent
AIF/DIF
45%
50%
51%
57%
48%
54%
60%
57%
54%
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Exhibit 4-4 shows that facilities with larger design flows tend to withdraw a higher
proportion of their design flow on a daily basis and the trend is more pronounced for
electric generators.
Exhibit 4-5 shows design intake flow values by industry type.
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-5. Design Intake Flow by Industry Type
Industry Type
Chemical and
Allied Products
Primary Metals
Paper and Allied
Products
Petroleum and
Coal Products
Food Products
Other
Manufacturing
Total
Manufacturers
Electric
Generators
Total
Estimated Number
of Facilities
185
95
227
39
38
7
592
671
1,262
Total Design
Intake Flow (MGD)
12,400
9,444
11,944
3,259
2,073
353
39,473
370,126
409,600
Percent of Total
Design Intake Flow
of All Facilities
3
2
3
1
0.5
0.1
10
90
100
Average Design
Intake Flow
(MGD)a
126
131
69
96
52
81
95
555
434
a Average based on surveyed facilities. May not be reflective of actual industry-wide average design intake flows.
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water
Intake Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include facilities identified as baseline closures. Design intake flow for Short Technical
Survey Facilities was imputed from average intake flow.
4.1.3 Source Waterbodies
Facilities potentially regulated under the proposed Existing Facilities rule can be found
on all waterbody types, but are predominantly located on freshwater rivers and streams.
Exhibit 4-6 below illustrates the distribution of facilities by waterbody type.
Exhibit 4-6. Distribution of Source Waterbodies for Existing Facilities
Source of Surface Water
Freshwater River or Stream
Lake or Reservoir
Great Lakes
Estuary or Tidal River
Ocean
Total
Electric Generators
Estimated
Number of
Facilities
349
134
48
117
22
671
Percent of
Facilities
52
20
7
17
3
100
Manufacturers
Estimated
Number of
Facilities
454
42
46
39
11
592
Percent of
Facilities
77
7
8
7
2
100
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include those facilities identified as baseline closures.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-7 focuses on facilities located on freshwater rivers and streams. In the 2004
Phase II rule, any freshwater facility whose DIP exceeded 5 percent of its source river's
mean annual flow (MAP) would have been subject to both impingement mortality and
entrainment requirements. The exhibit shows the withdrawal volumes for all facilities
that completed a detailed technical questionnaire.
Exhibit 4-7. Facility Intake Flows as a Percentage of Mean Annual Flow
Electric Generators
Manufacturers
Intake
Flow as
a % of
MAP
No Data
1-5%
5-10%
10-20%
20-40%
40-60%
60-80%
80-
100%
>100%
Total
Percent
Range
No Data
1-5%
5-10%
10-20%
20-40%
40-60%
60-80%
80-
100%
>100%
Total
DIP
No. of
Facilities
10
91
19
23
11
4
1
3
3
165
% of No.
of Fac.
6.06%
55.15%
11.52%
13.94%
6.67%
2.42%
0.61%
1.82%
1.82%
100.00%
No. of
Wgtd.
Fac.
10
93.31
19
23.14
11.39
4
1
3
3.28
168.12
% of No.
of Wgtd.
5.95%
55.50%
11.30%
13.76%
6.77%
2.38%
0.59%
1.78%
1.95%
100.00%
DIP
No. of
Facilities
7
143
6
8
7
0
1
4
2
178
% of No.
of Fac.
3.93%
80.34%
3.37%
4.49%
3.93%
0.00%
0.56%
2.25%
1.12%
100.00%
No. of
Wgtd.
Fac.
21.03
372.41
16.03
16.53
11.09
0
1.67
9.19
5.88
453.83
% of No.
of Wgtd.
4.63%
82.06%
3.53%
3.64%
2.44%
0.00%
0.37%
2.02%
1.30%
100.00%
AIF
No. of
Facilities
10
117
20
8
5
2
1
0
2
165
% of No.
of Fac.
6.06%
70.91%
12.12%
4.85%
3.03%
1.21%
0.61%
0.00%
1.21%
100.00%
No. of
Wgtd.
Fac.
10
119.45
20
8.23
5.17
2.14
1
0
2.14
168.13
% of No.
of Wgtd.
5.95%
71.05%
11.90%
4.90%
3.08%
1.27%
0.59%
0.00%
1 .27%
100.00%
AIF
No. of
Facilities
7
151
6
6
2
3
1
0
2
178
% of No.
of Fac.
3.93%
84.83%
3.37%
3.37%
1.12%
1 .69%
0.56%
0.00%
1.12%
100.00%
No. of
Wgtd.
Fac.
21.03
391.46
15.38
9.53
2.81
4.97
2.75
0
5.88
453.81
% of No.
of Wgtd.
4.63%
86.26%
3.39%
2.10%
0.62%
1.10%
0.61%
0.00%
1.30%
100.00%
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include those facilities identified as baseline closures.
Note: Extremely large withdrawal percentages may reflect flawed data or may represent facilities that withdraw as much
as 100% of the waterbody's flow (see, for example, the discussion on Monroe Power Plant in the Case Study Analysis
[DCN 4-0003] in the Phase II docket).
4.1.4 Cooling Water System Configurations
Facilities potentially regulated under the proposed Existing Facilities rule employ a
variety of cooling water system (CWS) types. Exhibit 4-8 shows the distribution of
cooling water system configurations.
4-7
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-8. Distribution of Cooling Water System Configurations
cws
Configuration
Once-through
Once-through
with Non-
recirculating
Pond
Once-through
with Non-
recirculating
Tower
Recirculating
with Tower
Recirculating
with Pond
Combination
Other
Total
All Facilities
Estimated
Number of
cwsa
1049
127
44
406
119
167
156
1,704
Percent of
Total CWS
62
8
3
24
7
10
9
100
Electric Generators
Estimated
Number of
CWS for
599
67
30
182
64
70
35
912
Percent of
Total CWS
66
7
3
20
7
8
4
100
Manufacturers
Estimated
Number of
CWS
450
60
14
224
55
97
121
793
Percent of
Total CWS
57
8
2
28
7
12
15
100
a Some facilities have more than one cooling water system. Some cooling systems have more than one type of CWS
configuration.
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include facilities identified as baseline closures.
Exhibit 4-9 shows the distribution of cooling water systems and the waterbody type from
which they withdraw.
Exhibit 4-9. Distribution of Facilities by Cooling Water System and Waterbody
Type
Waterbody
Type
Freshwater
Stream/River
Lake/Reservoir
Estuary /Tidal
River
Ocean
Great Lake
Total
Recirculating
Number
226.7
47
6.1
0
4
74
%of
Total
80%
17%
2%
0%
1%
100%
Once Through
Number
461.8
109.3
124.3
33.1
74.4
405
%of
Total
58%
14%
16%
4%
9%
100%
Combination
Number
114
19.6
26.3
0
15.9
57
%of
Total
65%
11%
15%
0%
9%
100%
Total
Number
803
176
156
33
94
1262
%of
Total
64%
14%
12%
3%
7%
100%
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-10 shows the distribution of cooling water system types at nuclear facilities.
Exhibit 4-10. Distribution of Cooling Water System Configurations
at Nuclear Facilities by Waterbody Type
CWS Type
Combination
Closed-Cycle
Once-Through
Waterbody Type
Ocean
Estuary/ Tidal River
Great Lake
Freshwater River
Lake/ Reservoir
Ocean
Estuary/ Tidal River
Great Lake
Freshwater River
Lake/ Reservoir
Ocean
Estuary/ Tidal River
Great Lake
Freshwater River
Lake/ Reservoir
Number of Facilities
0
0
1
3
4
0
2
3
14
4
5
8
6
5
7
Exhibit 4-10 shows that nuclear facilities (which are virtually always baseload
generators) with closed-cycle or combination cooling systems are most frequently located
on freshwater rivers and lakes. Also, there are no nuclear facilities with closed-cycle
cooling that withdraw from an ocean.
Exhibit 4-11 illustrates the intake structure arrangements for facilities potentially
regulated under the Proposed Rule.
Exhibit 4-11. Distribution of Cooling Water Intake Structure Arrangements
Intake Arrangement
Canal or Channel Intake
Bay or Cove Intake
Submerged Shoreline Intake
Surface Shoreline Intake
Submerged Offshore Intake
Total
Electric Generators
Estimated
Number of
Facilities
185
59
216
212
105
671
Percent of
Arrangements
28
9
32
32
16
100
Manufacturers
Estimated
Number of
Facilities
112
43
179
128
186
592
Percent of
Arrangements
19
7
30
22
32
100
Note: The sum of facilities for each arrangement exceeds the total since some facilities employ multiple intake
arrangements.
Source: Survey Data from Detailed and Short Technical Industry Questionnaires: Phase II Cooling Water Intake
Structures (DCN 4-0016F-CBI).
Note: All values are weighted and include facilities identified as baseline closures.
4-9
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-12 illustrates the distribution of cooling water system configurations as a
function of facility age. EPA does not have similar data on age of the cooling water
system, or age of the power producing equipment.
Exhibit 4-12. Estimated Distribution of Cooling Water System Configurations as a
Function of Age
CWS age
(Years)
< 10
10 to 20
20 to 40
>40
All
CWS
Configuration
Once-through
Recirculating
Combination
Other
Total
Once-through
Recirculating
Combination
Other
Total
Once-through
Recirculating
Combination
Other
Total
Once-through
Recirculating
Combination
Other
Total
Once-through
Recirculating
Combination
Other
Total
Electric Generators
Estimated
Number of
CWSs
4
9
4
0
17
21
24
1
0
47
224
63
29
3
319
332
21
37
5
396
581
117
71
9
779
Percent of
CWSs
0.5%
1%
1%
0%
2%
3%
3%
0.1%
0%
6%
29%
8%
4%
0.4%
41%
43%
3%
5%
0.7%
51%
75%
15%
9%
1%
100%
Manufacturers
Estimated
Number of
CWSs
18
10
16
0
44
27
41
31
3
102
82
36
53
12
183
221
60
101
49
431
348
147
201
64
760
Percent of
CWSs
2%
1%
2%
0%
6%
4%
5%
4%
0.4%
13%
11%
5%
7%
2%
24%
29%
8%
13%
6%
57%
46%
19%
26%
8%
100%
Based on detailed technical survey data. Numbers are estimated using weighting factors. Estimated total CWSs do not
match those in Exhibit 1-6 which are based on weighted detailed and short technical survey responses.
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
Exhibit 4-13 presents the distribution of in-scope facilities by the number of separate
cooling water systems at each facility.
Exhibit 4-13 shows that both electric generators and manufacturers have a similar
distribution of number of cooling water systems and that the majority use a single CWS.
4-10
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-13. Estimated Distribution of In-Scope Facilities by the Number of
Cooling Water Systems
Number of Cooling
Water Systems
1
2
3
4
5 or more*
Total
Electric Generators
Estimated
Number of
Facilities
506
115
33
12
5
671
Percent of
Facilities
75%
17%
5%
2%
1%
100%
Manufacturers
Estimated
Number of
Facilities
463
103
4
9
12
592
Percent of
Facilities
78%
17%
1%
1%
2%
100%
* The largest number of cooling water systems was 7.
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
4.1.5 Design and Operation of Cooling Water Intake Structures
Each CWS may be serviced by more than one cooling water intake structure (CWIS).
Exhibit 4-14 provides an estimate of the number and percent of facilities that have
multiple CWISs.
Exhibit 4-14. Estimated Distribution of In-Scope Facilities by the Number of
Cooling Water Intake Structures
Number of Cooling
Water Intake
Structures
1
2
3
4
5 or more*
Total
Electric Generators
Estimated
Number of
Facilities
450
146
45
16
14
671
Percent of
Facilities
67%
22%
7%
2%
2%
100%
Manufacturers
Estimated
Number of
Facilities
452
101
18
9
12
592
Percent of
Facilities
76%
17%
3%
2%
2%
100%
* The largest number of cooling water intake structures was 8.
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
Exhibit 4-14 shows that both electric generators and manufacturers have a similar
distribution of number of CWISs and that the majority of both use a single CWIS.
For those power generators with multiple intake structures, Exhibit 4-15 illustrates the
number of facilities that utilize closed-cycle cooling for at least some portion of the
facility's cooling system (i.e., a "combination" CWS).
4-11
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-15. Electric Generators with Multiple CWISs
CWS Type
Once-through only
Once-through only
Once-through only
Closed-cycle + once-through
Closed-cycle + once-through
Closed-cycle + once-through
Flow Range
<50 MGD
50-250 MGD
>250 MGD
<50 MGD
50-250 MGD
>250 MGD
Number of Facilities
7
35
150
0
2
5
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
Both mesh size and intake velocity affect impingement and entrainment reductions. In
particular, screen mesh size is an important factor affecting impingement and entrainment
rates. Exhibit 4-16 provides a national estimate of the number and percentage of facilities
utilizing different mesh size screens.
Exhibit 4-16. Estimated Distribution of Screen Mesh Size
Mesh Size (mm)
<5 mm (1/5 in)
>9.5-19 mm (3/8 - 3/4 in)
Other/Missing Data
Total
Electric Generators
Estimated
Number of
CWISs
21
885
97
1002
Percent of
CWISs
2%
88%
10%
100%
Manufacturers
Estimated
Number of
CWISs
115
347
171
633
Percent of
CWISs
18%
55%
27%
100%
Includes data for multiple CWISs and multiple screens at many facilities.
Assumes "other" and "missing" is >9.
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
These data show that at the time the technical survey was conducted, only a small
percentage of electric generators utilized fine mesh screens. EPA is aware that since then,
additional facilities have installed fine mesh screens.
Exhibit 4-17 below illustrates the wide range of design intake velocities at facilities
potentially regulated under the proposed rule.
4-12
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-17. Distribution of Cooling Water Intake Structure (CWIS) Design
Through-Screen Velocities
Velocity (feet per
second)
0-0.5
0.5-1
1 -2
2-3
3-5
5-7
>7
Total
Electric Generators
Estimated
Number of CWIS
148
200
316
162
35
10
23
893
Percent of
CWIS
17
22
35
18
4
1
3
100
Manufacturers
Estimated Number
of CWIS
165
85
84
57
27
6
13
436
Percent of
CWIS
38
20
19
13
6
1
3
100
Distribution of Cooling Water Intake Structure (CWIS) Design Through-Screen
Velocities (continued)
Velocity (feet per
second)
Average (fps
Unweighted
Median (fps
Unweighted)
Electric Generators
Estimated
Number of CWIS
1.9
1.4
Percent of
CWIS
Manufacturers
Estimated Number
of CWIS
1.6
1.0
Percent of
CWIS
Based on survey responses that provided data.
Note: The average design through-screen velocity for all surveyed cooling water intake structures (unweighted) is 1.8 feet
per second. The median design through-screen velocity for all surveyed facilities is 1.3 feet per second.
Source: Survey Data from Detailed and Short Technical Industry Questionnaire: (DCN 4-0016F-CBI).
Note: All values are weighted and include those facilities identified as baseline closures.
Exhibit 4-18 provides a national estimate of the number and percentage of cooling water
intake structures by average number of days operating for all intakes for which data was
reported. Data provided is based on a "typical" year for short technical survey facilities
and the year 1998 for the detailed technical survey facilities.
Exhibit 4-18. Estimated Distribution of Intakes by Average of CWIS Operating
Days
Average Intake
Operating Days
<60 days
60-180 days
180 -270 days
>270 days
Unknown
Total
Electric Generators
Estimated Number of
Facilities
81
113
81
684
58
1,017
Percent of
Facilities
8.0%
11.1%
8.0%
67.2%
5.7%
100.0%
Manufacturers
Estimated Number
of Facilities
37
23
26
676
56
819
Percent of
Facilities
4.6%
2.9%
3.2%
82.6%
6.8%
100.0%
Source: Survey Data from Detailed and Short Technical Industry Questionnaires.
4-13
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 4-18 shows that the intakes for manufacturers tend to operate more days per year
than electric generators. Nearly 75 percent of both types of facilities operate more than
270 days per year. For electric generators, the number of operating days is a component
of the capacity utilization rate (CUR); the other component is the proportion of the total
generating capacity actually generated during the operating period. The number of
operating days also gives an indication of the general amount of operational downtime
that may be available to help defray costs of compliance technology construction
downtime.
4.1.6 Existing Intake Technologies
Most facilities potentially regulated under the proposed Existing Facilities rule have
intake technologies already in place. Exhibit 4-19 illustrates the number of existing
facilities utilizing different types of intake technologies. EPA notes that not all intake
technologies may be sufficient to meet the performance standards or the requirements of
the rule. While not using an intake technology per se, facilities with cooling towers have
also been included in this table to demonstrate the usage of flow reduction as a method to
reduce impingement mortality and entrainment.
Exhibit 4-19. Distribution of Intake Technologies
Intake Technology Type
Bar Rack/Trash Rack
Screening Technologies
Passive Intake Technologies
Fish Diversion or Avoidance System
Fish Handling or Return System
No Intake Technologies
Cooling Tower
Total
Electric Generators
Estimated
Number of
Technologies
281
623
130
44
145
6
191
671
Percent of
Facilities
42
93
19
7
22
1
28
100
Manufacturers
Estimated
Number of
Technologies
403
431
205
36
23
14
209
592
Percent of
Facilities
68
73
35
6
4
2
35
100
Note: The total number of technologies exceeds the total number of facilities, since many facilities employ multiple intake
technologies.
Source: Survey Data from Detailed Industry Questionnaire: Phase II Cooling Water Intake Structures (DCN 4-0016F-
CBI).
Note: All values are weighted and include those facilities identified as baseline closures.
4.1.7 Age of Facilities
Exhibit 4-20 shows the age of existing generating units. As discussed in Chapter 5, this
data may not be entirely representative of the actual age of equipment used, as power
plants and manufacturers tend to be long-lived facilities that commonly add new units or
replace existing units.l
1 As a result, the age of the facility as a whole may not be representative of the age of its units; original
units may have been retired or replaced.
4-14
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-20. Age of Electric Generating Units by Fuel Type
Unit Age
(years)
>60
51-60
41-50
31-40
11-30
<10
Total
Coal
Units
22
275
271
218
167
9
962
%
2
29
28
23
17
1
Natural Gas
Units
11
119
137
276
121
180
844
%
1
14
16
33
14
21
Nuclear
Units
0
0
0
49
49
0
98
%
0
0
0
50
50
0
Oil
Units
8
27
123
241
41
16
456
%
2
6
27
53
9
4
Other
Units
0
6
1
0
13
3
23
%
0
26
4
0
57
13
Source: EIA Form 860 Database, year 2008 data.
Note: Data was not available for approximately 34 facilities.
As shown in Exhibit 4-20, over eighty percent of the coal-fired units are at least 30 years
of age and more than 31 percent of coal units are at least 50 years of age. Natural gas
facilities tend to be much newer and most nuclear powered units continue to operate
under a recently renewed 20 year operating license or are in the process of seeking such
renewals.2
4.1.8 Water Reduction Measures at Manufacturers
During EPA's site visits to manufacturing facilities, EPA noted many flow reduction
and/or water reuse practices being employed. Flow reductions were demonstrated
through process innovations, internal audits and leak checks, reengineering to capture lost
resources (e.g., water, heat), water reuse or conservation initiatives, process changes as a
result of effluent limitations guideline (ELG) requirements, and other similar activities.
EPA also reviewed specific ELG requirements and other incentive programs to identify
water reduction requirements and approaches. A summary of the findings is presented
below.
Site Visits
An overview of flow reduction information from the manufacturing site visits follows
below.3
2 As discussed in DCN 10-6876, there are indications that some nuclear units may operate well beyond the
initial projections for useful life.
3 For a complete discussion of EPA's site visits, see Chapter 2 of this Technical Development Document.
4-15
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
Manufacturing Site Notes on Intake Flow Reductions
ArcelorMittal — Indiana Harbor
Cargill — Hammond
Dow Chemical — Louisiana
Operations (Plaquemine)
Dow Chemical — St. Charles
Operations (SCO)
Sunoco — Marcus Hook
Sunoco — Philadelphia
US Steel— Gary
Valero — Delaware City
East side recirculates an estimated 569 MGD via underground
tunnel system and also has extensive cooling tower usage. West
side uses a mix of once-through and CCRS, with power plant using
most of once-through flow.
Reuses 1 0-1 5% of cooling water as process water. Other Cargill
sites reuse higher percentages. Cargill formed a corporate water
reduction team and has a company-wide goal of reducing water use
by 5% by 201 2.
60% of the heat load is processed through cooling towers, leading
to a commensurate reduction in flow.
4% of the heat load is processed through cooling towers.
Historical intake capacity (DIE) is 134 MGD, permitted limit (from
DRBC) is 43 MGD, and AIF is 17 MGD. Significant use of cooling
towers.
Converted several process lines to CCRS in the 1980s and has
significant water reuse and use of cooling towers. Actual flow
reductions not available, but AIF is very low.
A cooling tower recirculates approximately 148 MGD. Blast
furnaces and steel shop also converted to CCRS.
Added dry and wet cooling systems to new process lines.
Withdrawals are limited by DRBC; added towers in 1990s to
expand production without increasing heat load.
Effluent Limitations Guidelines (ELGs)
In addition to conducting site visits to observe water reduction practices, EPA also
researched ELGs to identify incentives and requirements for water reduction. ELGs are
technology-based regulations and are intended to represent the greatest pollutant
reductions that are economically achievable for a particular industrial category. As part of
the regulatory development process that EPA uses in developing technology-based ELGs
for industrial categories, EPA first gathers extensive information and data on the
industry's processes, discharge characteristics, technologies and practices used to treat,
minimize, or prevent wastewater discharges, as well as economic information.
Pollution prevention, management, and minimization practices have become a greater
focus in the ELG development process, especially since EPA has been establishing ELGs
for industrial categories and facilities that are not typical production facilities (i.e., airport
deicing, construction and development, and concentrated aquatic animal production
(aquaculture) facilities among others). EPA is also required by the CWA to reexamine
existing ELGs to ensure they are still representative of the industrial category and meet
the current levels of treatment technology (BAT, BCT, BPT, NSPS, PSES, and PSNS).
For those industrial categories whose ELGs are being revised, new pollution prevention
practices are thoroughly examined in addition to the traditional end-of-pipe treatment
technologies.
As part of developing ELGs for various industry sectors, EPA typically assesses water
use, technologies in place, and industry trends. The documents developed by EPA as part
4-16
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
of this process provide the most accurate description of historic changes in water
withdrawals on an industry or process/subcategory level.
For example, the factors used in developing the subcategories for the revised iron and
steel ELG included:
• Age of equipment and facilities;
• Location;
• Size of the site;
• Manufacturing processes employed;
• Wastewater characteristics; and
• Non-water quality environmental impacts
Of the areas mentioned above, EPA determined that manufacturing processes and the
resultant wastewater characteristics were the most significant factors for possible
subcategorization of the industry. Detailed discussions of water use, pollutants generated,
and production-normalized flow rates are found throughout the technical development
document (TDD). As part of the iron and steel regulatory development effort, EPA
examined the following:
• In-process technologies and process modifications;
• Process water recycle technologies;
• Process water discharge flow rates;
• End-of-pipe wastewater treatment technologies; and
• Treated process wastewater effluent quality
Section 8 of the iron and steel TDD4 provides examples of wastewater minimization
technologies. For example, high-rate recycling can recycle approximately 95 percent or
more from a process for reuse. As with other metal processes, countercurrent cascade
rinsing can reduce water use by up to 90 percent while other discussions demonstrate
process modifications that can result in the reduction of process water volumes by either
extending the amount of time water can be utilized within a process or reducing the
volume of process water required.
In the metal products and machinery ELG, a section of the TDD5 discusses pollution
prevention practices and wastewater reduction technologies. EPA estimated in the TDD,
Section 8, that the use of flow reduction technologies can reduce water use by as much as
50 to 90 percent at applicable facilities.
4 Iron and Steel Manufacturing Point Source Category Final Rule: Development Document. EPA 821-R-
02-004. Available at http://water.epa.gov/scitech/wastetech/guide/ironsteel/tdd.cfm.
5 Effluent Guidelines, Metal Products and Machinery: Final Rule Development Document. EPA-821-B-03-
001. Available at http://water.epa.gov/scitech/wastetech/guide/mpm/tdd_index.cfm.
4-17
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
In the organic chemicals, plastics, and synthetic fibers TDD,6 water conservation and
reuse technologies are described although no estimates in reducing flow volumes are
presented.
Economic considerations play a large role in the efficient utilization of water within
many industrial sectors. Recovering chemicals from waste streams can lower chemical
costs but can also greatly reduce treatment expenses for wastewater discharges. In
addition, efficient use of water within processes, cooling water for example, can improve
process efficiencies throughout the rest of the facility (heated water can then be utilized
by other processes in the plant). Leaks and spills at industrial facilities not only present
productivity issues, but can possibly lead to health and safety issues.
Incentive Programs
EPA has also developed voluntary incentive programs for facilities that wish to go
beyond the minimum regulatory requirements established in the applicable ELG. An
example is the Voluntary Advanced Technology Incentives Program (VATIP)
established as part of the revised National Emissions Standards for Hazardous Air
Pollutants for Source Category: Pulp and Paper Production; Effluent Limitations
Guidelines, Pretreatment Standards, and New Source Performance Standards: Pulp,
Paper, and Paperboards (also known as the Pulp and Paper Cluster Rule). EPA
established the VATIP to encourage facilities subject to the Bleached Papergrade Kraft
and Soda Subcategory to achieve greater pollutant reductions by implementing pollution
prevention controls. Pulp and paper mills that enroll in the VATIP receive additional time
to comply with the regulation and have reduced monitoring requirements, among other
incentives.
The VATIP comprises three tiers that represent increasingly more effective levels of
environmental protection. Mills enrolled in the program have extended compliance dates
in which to meet the requirements for each tier. Facilities that enter in to VATIP are
required to prepare a milestone plan that reflects how the mill will achieve the limitations
for their selected tier. This milestone plan can assist permitting authorities in developing
interim limitations and requirements in NPDES permits. EPA established three phases to
measure a facility's progress in complying with permit requirements and to ensure
compliance with the tier limitations. The three phases include:
• Initial limitations
• Intermediate milestones; and
• Ultimate limitations
The initial limitations must reflect either the existing effluent quality or the current
technology-based limits in the mill's current permit, whichever is more stringent. This is
for those pollutants (or flows) that are part of the VATIP. Under the Clean Water Act
(CWA), facilities must comply with best available technology economically achievable
6 Development Document for 1987 Effluent Limitations Guidelines and Standards for OCPSF. EPA 440-1-
87-009. Available at http://water.epa.gov/scitech/wastetech/guide/ocpsf/index.cfm.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
(BAT) effluent limitations promulgated after March 31, 1989 immediately (CWA
§301(b)(2)). Under the VATIP, the limitations for the various tiers eventually become the
BAT limits for those facilities. The pulp and paper ELG requires immediate compliance
with ELG limits, but only if they have become enforceable BAT limits.
The intermediate milestones include the establishment of intermediate BAT limitations
and the possible inclusion of interim milestones reflective of the facility moving forward
to achieve the required limitations for the respective tier.
The ultimate limitations require the facility to meet the final effluent limitations for the
applicable tier no later than the date specified in the regulation.
In addition to the time to allow participating facilities to meet the more stringent effluent
limits, facilities participating in the VATIP is the reduction in monitoring requirements.
Based on the tier chosen, monitoring frequencies are reduced once the facility has
demonstrated it has reached the intermediate milestones (stage 2).
4.1.9 Land-based Liquefied Natural Gas Facilities
EPA's research also indicates that there are five existing land-based liquefied natural gas
(LNG) facilities in the United States, all on the East coast. LNG facilities may withdraw
hundreds of MGD of seawater for warming (re-gasification). Some existing LNG
facilities may withdraw water and use 25 percent or more of the for cooling purposes. As
discussed in section V of the preamble to the proposed Existing Facilities rule, EPA has
not identified a uniformly applicable and available technology for minimizing
impingement and entrainment mortality at these facilities. However, technologies may be
available for some existing LNG facilities. LNG facilities that withdraw any volume of
water for cooling purposes would be subject to case-by-case, best professional judgment
BTA determinations under the proposed rule.
4.2 Electricity Industry
The electricity industry is made up of three major functional service components or
sectors: generation, transmission, and distribution. Each of these terms is defined as
follows (Beamon, 1998; Joskow, 1997):
• The generation sector includes power plants that produce, or "generate,"
electricity.7 Electric energy is produced using a specific generating technology,
for example, internal combustion engines and turbines. Turbines can be driven by
wind, moving water (hydroelectric), or steam from fossil fuel-fired boilers or
nuclear reactions. Other methods of power generation include geothermal or
photovoltaic (solar) technologies.
• The transmission sector can be thought of as the interstate highway system of the
business - the large, high-voltage power lines that deliver electricity from power
plants to distribution centers using a complex system. Transmission requires:
interconnecting and integrating a number of generating facilities into a stable,
The terms "plant" and "facility" are used interchangeably throughout this profile and document.
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
synchronized, alternating current (AC) network; scheduling and dispatching all
connected plants to balance the demand and supply of electricity in real time; and
managing the system for equipment failures, network constraints, and interaction
with other transmission networks.
• The distribution sector can be thought of as the local delivery system - the
relatively low-voltage power lines that take power from a distribution center and
bring it to homes and businesses. Electricity distribution relies on a system of
wires and transformers along streets and underground to provide electricity to the
ultimate end user: residential, commercial, and industrial consumers. The
distribution system involves both the provision of the hardware (for example,
lines, poles, transformers) and a set of retailing functions, such as metering,
billing, and various demand management services.
Of the three industry sectors, only electricity generation uses cooling water and is,
therefore, subject to Section 316(b) regulations.
4.2.1 Domestic Production
This section presents an overview of U.S. generating capacity and electricity generation
for the year 2007.8 The rating of a generating unit is a measure of its ability to produce
electricity.9 Generator ratings are expressed in megawatts (MW). Nameplate capacity
and net capability are the two common measurements (U.S. DOE, 2000a) and are defined
as follows:
Nameplate capacity is the full-load continuous output rating of the generating unit under
specified conditions, as designated by the manufacturer.
Net capability is the steady hourly output that the generating unit is expected to supply to
the system load, as demonstrated by test procedures. The capability of the generating unit
in the summer is generally less than in the winter due to higher ambient-air and cooling-
water temperatures, which cause generating units to operate less efficiently. The
nameplate capacity of a generating unit is generally greater than its net capability.
Exhibit 4-21 shows the net US generating capacity from 2000 to 2009 by fuel type.
8 2007 is the most recent year that detailed data is available. EPA has updated this information since the
2002 proposed Phase II rule, which used data from 1999.
9 The numbers presented in this section are capability for utility facilities and capacity for nonutilities. For
convenience purposes, this section will refer to both measures as "capacity."
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
Exhibit 4-21. Existing Generating Capacity by Energy Source (2000 to 2009)
Net Summer Generating Capacity by Fuel Type
450,000
400,000
350,000 • ""
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
_ 300,000
§. 250,000
>
±i
£ 200,000
Q.
3
150,000
100,000
50,000
0
Petroleum — '—Natural Gas Nuclear
.;' Hydroelectric Wind Other
Note 1 : Data reflects summer month capacity, during peak consumption.
Note 2: "Other" is a combination of the following: other gases (e.g., blast furnace gas, propane gas); solar; wood; and
other renewables.
Source: DOE 2010. Table ES-1.
Exhibit 4-21 shows that the majority of capacity increases over the past 10 years have
been fueled by natural gas, with a minor increase in wind power in recent years.
4.2.2 Prime Movers
Electric power plants use a variety of prime movers to generate electricity. The type of
prime mover used at a given plant is determined based on the type of load the plant is
designed to serve, the availability of fuels, and energy requirements. Most prime movers
use fossil fuels (coal, petroleum, and natural gas) as an energy source and employ some
type of turbine to produce electricity. The six most common prime movers are (U.S.
DOE, 2000a):
• Steam Turbine: Steam turbine or "steam electric" units require a fuel source to
boil water and produce steam that drives the turbine. Either the burning of fossil
fuels or a nuclear reaction can be used to produce the heat and steam necessary to
generate electricity. These units are often baseload units that are run continuously
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
to serve the constant load required by the system. Steam electric units generate the
majority of electricity produced at power plants in the U.S.10
• Gas Combustion Turbine: Gas turbine units burn a combination of natural gas
and distillate oil in a high pressure chamber to produce hot gases that are passed
directly through the turbine. Units with this prime mover are generally less than
100 megawatts in size, less efficient than steam turbines, and used forpeakload
operation serving the highest daily, weekly, or seasonal loads. Gas turbine units
have quick startup times and can be installed at a variety of site locations, making
them ideal for peak, emergency, and reserve-power requirements. These units do
not use a steam loop and do not use cooling water; waste heat is discharged to the
atmosphere.
• Combined-Cycle Turbine: Combined-cycle units utilize both steam and gas
turbine prime mover technologies to increase the efficiency of the gas turbine
system. After combusting natural gas in gas turbine units, the hot gases from the
turbines are transported to a waste-heat recovery steam boiler where water is
heated to produce steam for a second steam turbine.3 The steam may be produced
solely by recovery of gas turbine exhaust or with additional fuel input to the steam
boiler. Combined-cycle generating units are generally used for intermediate
loads. These units use a steam loop in the steam turbine portion of the process and
use cooling water to convert the steam back to water.
• Internal Combustion Engines: Internal combustion engines contain one or more
cylinders in which fuel is combusted to drive a generator. These units are
generally about 5 megawatts in size, can be installed on short notice, and can
begin producing electricity almost instantaneously. Like gas turbines, internal
combustion units are generally used only for peak loads. These units do not use a
steam loop and do not use cooling water; waste heat is discharged to the
atmosphere.
• Water Turbine: Units with water turbines, or "hydroelectric units," use either
falling water or the force of a natural river current to spin turbines and produce
electricity. These units are used for all types of loads. These units do not use a
steam loop and do not use cooling water, as they typically do not generate excess
waste heat.
• Other Prime Movers: Other types of prime movers include binary cycle turbine
(geothermal), photovoltaic (solar), wind turbine, and fuel cell prime movers. The
contribution of these prime movers is small relative to total power production in
the U.S., but the role of these prime movers may expand in the future because
recent legislation includes incentives for their use. Generally, with the exception
of binary cycle turbines, these movers do not generate excess waste heat. Binary
cycle turbines generally use cooling towers to dissipate waste heat.
Exhibit 4-22, which is based on DOE's Form EIA-860, provides data on existing power
generating plants by prime mover. This exhibit includes all facilities in the electric power
10 The steam is contained in a steam loop that is separate from the cooling water system and is, therefore,
not the focus of this rule. Cooling water is used to convert steam back to water.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
industry (i.e., not just facilities subject to 316(b)) that have at least one non-retired unit
and that submitted Form EIA-860 (Annual Electric Generator Report) in 2007.u For this
analysis, EPA classified facilities as "steam turbine" or "combined-cycle" if they had at
least one generating unit of that type; facilities with both steam turbine- and combined-
cycle-based capacity were classified by the largest capacity generating unit. Facilities that
had no steam electric units were classified under the prime mover of the largest capacity
generating unit.
Section 316(b) is only relevant for electric generators that use cooling water. However,
not all prime movers require cooling water. Only prime movers with a steam-electric
generating cycle use large enough amounts of cooling water to fall under the scope of the
proposed rule. EPA identified the two types of prime movers (steam turbine and
combined-cycle steam turbine) that constitute the steam electric prime movers of
interest.12
Using this list of steam electric prime movers and DOE's Annual Electric Generator
Report (which collects data to create an annual inventory of utilities and operating status
of units), EPA identified the facilities that have at least one generating unit with a steam
electric prime mover. The rest of this profile will focus on the generating plants with a
steam electric prime mover (i.e., steam turbine or combined-cycle).
Exhibit 4-22. Number of Existing Utility and Nonutility Facilities
by Prime Mover, 2007
Prime Mover
Steam Turbine
Combined-Cycle
Gas Turbine
Internal Combustion
Hydroelectric
Other
Total
Number of Facilities
1,349
453
834
1,005
1,368
365
5,374
a Facilities are listed as steam electric if they have at least one steam electric generating unit.
b Facility counts are weighted estimates generated using the original 316(b) survey weights.
Sources: U.S. EPA, 2000; U.S. DOE, 2007.
11 Note that EPA's technology assessments and compliance cost estimates are based upon data that EPA
collected through industry questionnaires. This technology data represents the year 2000. Since EPA has
not collected any new information on intake technologies, intake flows, etc. for the Existing Facilities
proposed rule, EPA is continuing to use the 2000 questionnaire data for some analyses as it reflects the best
information available. However, because more recent economic information is available through existing
sources, EPA conducted the economic analyses using 2007 data to more accurately account for possible
impacts. As a result, some of the information presented in this chapter reflects the year 2000 while other
reflects the year 2007.
12 EIA identifies 11 other categories of prime mover, but these categories are not subject to 316(b).
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
4.2.3 Steam Electric Generators
Exhibit 4-23 provides summary data concerning the number of utilities/operators, number
of plants, generating units, and total nameplate capacity. The table provides information
for the industry as a whole, for the steam electric part of the industry, and for the part of
the industry potentially subject to the proposed Existing Facilities rule.
Exhibit 4-23. Summary of 316(b) Electric Power Facility Data
Utilities/Operators11
Plants"
Units8
Nameplate Capacity (MW)
Total'
2,537
5,374
17,250
1,072,497
Steam Electric'
Number
1,158
1,805
4,828
790,690
% of Total
46%
34%
28%
74%
316(b)b'c
Number
233
559
2,132
480,388
% of Total
9%
10%
12%
45%
a Data are for regulated and non-regulated entities.
b Number of units and capacity include steam and non-steam units and capacity, respectively, at 316(b) electric power
facilities.
0 Number of plants, number of units, and capacity are weighted estimates and are generated using the original 316(b)
survey weights.
d Utilities/operators and plants are listed as steam electric if they have at least one non-retired steam electric unit.
e Total number of units includes non-steam generating units at facilities previously considered for the 316(b) regulation
that have retired all of their steam generating units. Because these facilities no longer have steam operations they are
excluded from the currently analyzed 316(b) universe.
f Estimates exclude facilities that have retired all of their operations - steam and non-steam - according to the 2010 base-
case IPM run.
From the universe of facilities with a steam electric prime mover and based on data
collected from EPA's industry technical questionnaires and the compliance requirements
for the proposed rule, EPA has identified 559 facilities to which the proposed rule is
expected to apply.13 All of these facilities are in the set of 554 facilities that were
expected to comply with the suspended 2004 Phase II Final Rule and 117 electric
generators with design intake flow between 2 and 50 MGD excluded from the 2006
Phase III Final Rule; however, based on 2007 EIA data and IPM data, a total of 93 of the
671 Phase II and Phase III facilities will have retired by 2012.14 In addition, 19 coastal
facilities are subject to the California "Policy on the Use of Coastal and Estuarine Waters
for Power Plant Cooling."15 Exhibit 4-24 provides a summary of the estimated number
of facilities considered in the economic analysis under previous and current 316(b)
regulation development.
13 EPA developed the estimates of the number and characteristics of facilities expected to be within the
scope of the proposed rule using the facility sample weights that were developed for the suspended 2004
Phase II rule and the 2006 Phase III Rule. These weights provide comprehensive estimates of the total
number of in-scope facilities based on the full set of facilities sampled in EPA's industry questionnaires.
See the preamble to the proposed rule and the EBA for further discussion of the sample weights used in this
analysis.
14 Individual values do not sum to reported totals due to rounding as the result of the application of
statistical weights.
15 As described in the EBA, these 19 facilities were not included in the economic analysis for the proposed
rule, as they are subject to requirements under the state's cooling water policy, which contains similar
requirements to the proposed rule.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 4: Industry Description
Exhibit 4-24. Number of 316(b) Regulated Facilities
Phase ll/lll
EIA-Retiredb'c
IPM-Retiredb
Coastal CA
Currently Analyzed
Unweighted
Phase II
543
41
31
17
454
Phase III
113
11
8
0
94
Total
656
52
39
17
548
Weighted3
Phase II
554
43
31
19
461
Phase III
117
11
8
0
98
Total
671
54
39
19
559
a Facility counts generated using the original 316(b) survey weights.
b A facility is considered retired if it no longer has any steam operations even though it may still operate non-steam units.
0 Includes facilities that have already retired and those that will do so before 2012 (i.e., the rule promulgation).
Sources: U.S. EPA, 2000; U.S. DOE, 2007 (GenY07); U.S. EPA Analysis, 2010.
Exhibit 4-25 presents the estimated number of 316(b) facilities by fuel type and prime
mover category.
Facilities have multiple generating units and each unit uses only one type of prime
mover. However, many facilities operate units with different types of prime movers. EPA
estimates that 12 of the 525 steam turbine facilities also operate combined-cycle
generating units and that 10 of the 33 combined-cycle facilities also operate steam turbine
generating units. The data shown in Exhibit 4-23 are based on total capacity by prime
mover type and do not necessarily indicate which prime mover type predominates with
regard to annual power generation.
Exhibit 4-25. 316(b) Electric Power Facilities by Plant Type and Prime Mover
Plant Type3
Coal Steam
Gas
Nuclear
Oil
Other Steam
Total Steam
Combined-Cycle
Total
Prime Mover
Steam Turbine
Steam Turbine
Steam Turbine
Steam Turbine
Steam Turbine
Steam Turbine
Combined-Cycle
Number of 316(b) Electric
Generators'3'0
342
73
56
29
25
525
33
559
B Facilities are listed as steam electric if they have at least one steam electric generating unit.
b Facility counts are weighted estimates generated using the original 316(b) survey weights.
Sources: U.S. EPA, 2000; U.S. DOE, 2007 (GenY07); U.S. EPA Analysis, 2010
c Individual values do not sum to reported total due to rounding as the result the application of statistical
weights.
4.3 Manufacturers
4.3.1 Electric Generation at Manufacturers
Some manufacturing facilities also produce electricity (cogeneration). According to data
from the 316(b) questionnaire, 164 manufacturing facilities responded that they had
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Chapter 4: Industry Description
§ 316(b) Existing Facilities Proposed Rule - TDD
produced electricity in 1996, 1997, or 1998.16 One hundred eleven (111) facilities
responded that they did not generate electricity during the survey period. Twelve (12)
facilities did not respond to the question.
Exhibit 4-26 shows the proportion of the 38 manufacturers that use coal as their primary
fuel source.
Exhibit 4-26. Manufacturers with Coal-Fired Generation
Total Facility Coal-fired Generation
Capacity (MW)
0-25
25-50
50-100
100-200
>200
Total
Number of Facilities
15
8
9
4
2
38
The six largest manufacturers (i.e., those with a generating capacity above 100MW) came
from 5 industry sectors: steel works (SIC 3312), iron ore (1011), electric services/non-
ferrous metals (4911/3339), chemical (2800), and sanitary paper (2676).
4.4 Glossary
Baseload: The minimum amount of electric power delivered or required over a given
period of time at a steady rate.
Baseload Generating Unit: A baseload generating unit is normally used to satisfy all or
part of the minimum or base load of the system and, as a consequence, produces
electricity at an essentially constant rate and runs continuously. Baseload units are
generally the newest, largest, and most efficient of the three types of units.
(http://www.eia.doe.gov/cneaf/electricity/page/prim2/chapter2.html)
Capacity Utilization Rate: The ratio between the average annual net generation of power
by the facility (in MWh) and the total net capability of the facility to generate power (in
MW) multiplied by the number of hours during a year.
Combined-Cycle: An electric generating technology in which electricity is produced
from otherwise lost waste heat exiting from one or more gas (combustion) turbines. The
exiting heat is routed to a conventional boiler or to heat recovery steam generator for
utilization by a steam turbine in the production of electricity. This process increases the
efficiency of the electric generating unit.
16 Answered yes to Question 15(a) of the 3 l(6)b detailed industry questionnaire for manufacturers, which
requested information on whether the facility generated electricity during the time period covered by the
survey.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
Combined-Cycle Unit: An electric generating unit that consists of one or more
combustion turbines and one or more boilers with a portion of the required energy input
to the boiler(s) provided by the exhaust gas of the combustion turbine(s).
Distribution: The delivery of energy to retail customers (including homes, businesses,
etc...).
Distribution System: The portion of an electric system that is dedicated to delivering
electric energy to an end user.
EIA: The Energy Information Administration (EIA), created by Congress in 1977, is a
statistical agency of the U.S. Department of Energy.
Electricity Available to Consumers: Power available for sale to customers.
Approximately 8 to 9 percent of net generation is lost during the transmission and
distribution process.
Gas Turbine Plant: A plant in which the prime mover is a gas turbine. A gas turbine
typically consisting of an axial-flow air compressor and one or more combustion
chambers, where liquid or gaseous fuel is burned and the hot gases are passed to the
turbine and where hot gases expand to drive the generator and are then used to run the
compressor.
Generation: The process of producing electric energy or the amount of electric energy
produced by transforming other forms of energy, commonly expressed in kilowatt-hours
(kWh) or megawatt-hours (MWh).
Gross Generation: The total amount of electric energy produced by the generating units
at a generating station or stations, measured at the generator terminals.
Internal Combustion Plant: A plant in which the prime mover is an internal combustion
engine. An internal combustion engine has one or more cylinders in which the process of
combustion takes place, converting energy released from the rapid burning of a fuel-air
mixture into mechanical energy. Diesel or gas-fired engines are the principal fuel types
used in these generators. The plant is usually operated during periods of high demand for
electricity.
Kilowatt (kW): One thousand watts (W).
Kilowatt-hour (kWh): One thousand watt-hours (Wh).
Megawatt (MW): One thousand kilowatts (kWh).
Megawatt-hour (MWh): One thousand kilowatt-hours (kWh)
Nameplate Capacity: The amount of electric power delivered or required for which a
generator, turbine, transformer, transmission circuit, station, or system is rated by the
manufacturer.
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
Net Capacity (Capability): The amount of electric power delivered or required for which
a generator, turbine, transformer, transmission circuit, station, or system is rated by the
manufacturer, exclusive of station use, and unspecified conditions for given time interval.
Net Generation: Gross generation minus plant use from all electric utility owned plants.
The energy required for pumping at a pump storage plant is regarded as plant use and
must be deducted from the gross equation.
Nonutility Power Producer: A corporation, person, agency, authority, or other legal
entity or instrumentality that owns electric generating capacity and is not an electric
utility. Nonutility power producers include qualifying cogenerators, qualifying small
power producers, and other nonutility generators (including independent power
producers) without a designated franchised service area that do not file forms listed in the
Code of Federal Regulations, Title 18, Part 141.
(http://www.eia.doe.gov/emeu/iea/glossary.html)
Peakload: The maximum load during a specified time period.
Peakload Generating Unit: A peakload generating unit, normally the least efficient of
the three unit types, is used to meet requirements during the periods of greatest, or peak,
load on the system, (http://www.eia.doe.gov/cneaf/electricity/page/prim2/chapter2.html)
Prime Movers: The engine, turbine, water wheel or similar machine that drives an
electric generator; or, for reporting purposes, a device that directly converts energy to
electricity directly (e.g., photovoltaic solar, and fuel cell(s)).
Regulated Entity: For the purpose of EIA's data collection efforts, entities that either
provide electricity within a designated franchised service area and/or file forms listed in
the Code of Federal Regulations, Title 18, part 141 are considered regulated entities. This
includes investor-owned electric utilities that are subject to rate regulation, municipal
utilities, federal and state power authorities, and rural electric cooperatives. Facilities that
qualify as cogenerators or small power producers under the Public Utility Regulatory
Power Act (PURPA) are not considered regulated entities.
Reliability: Electric system reliability has two components: adequacy and security.
Adequacy is the ability of the electric system to supply customers at all times, taking into
account scheduled and unscheduled outages of system facilities. Security is the ability of
the electric system to withstand sudden disturbances, such as electric short circuits or
unanticipated loss of system facilities. The degree of reliability maybe measured by the
frequency, duration, and magnitude of adverse effects on consumer services.
(http://www.eia.doe.gov/cneaf/electricity/epavl/glossary.html)
Steam Electric Power Plant: A plant in which the prime mover is a steam turbine. The
steam used to drive the turbine is produced in a boiler where fossil fuels are burned.
Transmission: The movement or transfer of electric energy over an interconnected group
of lines and associated equipment between points of supply and points at which it is
transformed for delivery to consumers, or is delivered to other electric systems.
Transmission is considered to end when the energy is transformed for distribution to the
consumer.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 4: Industry Description
Utility: A corporation, person, agency, authority, or other legal entity or instrumentality
that owns and/or operates facilities within the United States, its territories, or Puerto Rico
for the generation, transmission, distribution., or sale of electric energy primarily for use
by the public, with a dedicated service area, and files forms listed in the Code of Federal
Regulations, Title 18, Part 141. Facilities that qualify as cogenerators or small power
producers under the Public Utility Regulatory Policies Act (PURPA) are not considered
electric utilities, (http://www.eia.doe.gov/emeu/iea/glossary.html)
Water Turbine: A unit in which the turbine generator is driven by falling water.
4.5 References
Beamon, J.A. 1998. Competitive Electricity Prices: An Update. From the Phase I Rule
Record. DCN 1-2110-EA.
Joskow, P. L. 1997. Restructuring, Competition and Regulatory Reform in the U.S.
Electricity Sector. DCN1-2118-EA.
U.S. Department of Energy (U. S. DOE). 2009. Energy Information Administration
(EIA). Electric Power Annual 2009. Released: November 23, 2010. Table ESI at:
http://www.eia.doe.gov/cneaf/electricity/epa/epaxlfileesl.pdf
U.S. Department of Energy (U.S. DOE). 2007. Form EIA-860 (2007). Annual Electric
Generator Report.
U.S. Department of Energy (U.S. DOE). 2002. Energy Information Administration
(EIA). Status of State Electric Industry Restructuring Activity as of March 2002.
At: http://www.eia.doe.gov/cneaf/electricity/chg str/regmap.html.
U.S. Department of Energy (U.S. DOE). 2001. Energy Information Administration
(EIA). Annual Energy Outlook 2002 With Projections to 2020. DOE/EIA-
0383(2002). December 2001.
U.S. Department of Energy (U.S. DOE). 2000a. Energy Information Administration
(EIA). Electric Power Industry Overview. At:
http://www.eia.doe.gov/cneaf/electricity/page/prim2/toc2.html.
U.S. Department of Energy (U. S. DOE). 2000b. Energy Information Administration
(EIA). Electric Power Annual 1999 Volume I. DOE/EIA-0348(99)/1.
U.S. Department of Energy (U. S. DOE). 2000c. Energy Information Administration
(EIA). Electric Power Annual 1999 Volume II. DOE/EIA-0348(99)/2.
U.S. Department of Energy (U.S. DOE). 1999a. Form EIA-860A (1999). Annual Electric
Generator Report - Utility.
U.S. Department of Energy (U.S. DOE). 1999b. Form EIA-860B (1999). Annual Electric
Generator Report - Nonutility.
U.S. Department of Energy (U.S. DOE). 1999c. Form EIA-861 (1999). Annual Electric
Utility Data.
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Chapter 4: Industry Description § 316(b) Existing Facilities Proposed Rule - TDD
U.S. Department of Energy (U.S. DOE). 1999d. Form EIA-759 (1999). Monthly Power
Plant Report.
U.S. Department of Energy (U.S. DOE). 1998a. Energy Information Administration
(EIA). Electric Power Annual 1997 Volume I. DOE/EIA-0348(97/1).
U.S. Department of Energy (U.S. DOE). 1998b. Energy Information Administration
(EIA). Electric Power Annual 1997 Volume II. DOE/EIA-0348(97/1).
U.S. Department of Energy (U.S. DOE). 1998c. Form EIA-861 (1998). Annual Electric
Utility Data.
U.S. Department of Energy (U.S. DOE). 1996a. Energy Information Administration
(EIA). Electric Power Annual 1995 Volume I. DOE/EIA-0348(95)/1.
U.S. Department of Energy (U.S. DOE). 1996b. Energy Information Administration
(EIA). Electric Power Annual 1995 Volume II. DOE/EIA-0348(95)/2.
U.S. Department of Energy (U. S. DOE). 1996c. Energy Information Administration
(EIA). Impacts of Electric Power Industry Restructuring on the Coal Industry. At:
http://www.eia.doe.gov/cneaf/electricity/chg_str_fuel/html/chapterl.html.
U.S. Department of Energy (U.S. DOE). 1995a. Energy Information Administration
(EIA). Electric Power Annual 1994 Volume I. DOE/EIA-0348(94/1).
U.S. Department of Energy (U.S. DOE). 1995b. Energy Information Administration
(EIA). Electric Power Annual 1994 Volume II. DOE/EIA-0348(94/1).
U.S. Environmental Protection Agency (U.S. EPA). 2000. Section 316(b) Industry
Survey. Detailed Industry Questionnaire: Phase II Cooling Water Intake
Structures and Industry Short Technical Questionnaire: Phase II Cooling Water
Intake Structures, January, 2000 (OMB Control Number 2040-0213). Industry
Screener Questionnaire: Phase I Cooling Water Intake Structures, January, 1999
(OMB Control Number 2040-0203).
U.S. Geological Survey (USGS). 1995. Estimated Use of Water in the United States in
1995. At: http://water.usgs.gov/watuse/pdfl995/html/.
4-30
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 5: Subcategorization
Chapter 5: Subcategorization
5.0 Introduction
This section describes EPA's consideration of subcategories for the proposed rule.
Section 5.1 discusses the methodology and factors considered when evaluating potential
subcategories for the rule. The remainder of the chapter discusses EPA's analysis of each
factor.
5.1 Methodology and Factors Considered for Basis of
Subcategorization
In the development of other technology-based CWA regulations such as effluent
limitations guidelines, EPA is required to consider a number of different factors. Among
others, these include the age of the equipment and facilities in the category,
manufacturing processes employed, types of treatment technology to reduce effluent
discharges, and the cost of effluent reductions (Section 304(b)(2)(b) of the CWA, 33
U.S.C. 1314(b)(2)(B)). The statute also authorizes EPA to take into account other factors
that the Administrator deems appropriate.
While the 316(b) language does not specifically require EPA to consider subcategories,
EPA concludes it is reasonable to do so because 316(b) requirements are similarly
technol ogy-b ased.
EPA considered a number of factors as a basis of Subcategorization in determining best
technology available. The major factors EPA considered are:
• the age of facility or unit;
• electricity generation or manufacturing process;
• existing intake type;
• application of various impingement and entrainment reduction technologies;
• geographical location;
• facility size;
• non-water quality environmental impacts (including energy requirements); and
• the cost of achieving impingement and entrainment reductions.
The following sections discuss EPA's consideration of these factors with the exception of
the cost of achieving impingement and entrainment reductions. See the Economic
Analysis (EA) for those analyses.
5.2 Age of the Equipment and Facilities
As discussed in Chapter 4, many power plants and manufacturers have been in operation
for many years. Existing units may operate for decades before being replaced by new or
5-1
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Chapter 5: Subcategorization § 316(b) Existing Facilities Proposed Rule - TDD
more efficient units or retired altogether. EPA considered the age of equipment as a
Subcategorization basis. EPA concluded this is not an appropriate basis because power
plants and manufacturing facilities tend to be long-lived facilities and have regular
maintenance, equipment upgrades, plant expansions, and other activities. Equipment
such as intake technologies is generally included in the scheduled maintenance. Factors
such as the waterbody type, debris loading, and other site-specific factors will dictate
how frequently a facility needs to replace this equipment. EPA did not find that the age
of facilities or equipment changed the need of such facilities for cooling water (since
gains in efficiency have typically been used to maintain or increase power production or
productivity), or the impacts associated with cooling water use. Nor did EPA identify
significantly different CWIS technologies based on facility age.
Using information collected through the industry questionnaire, site visits, and
conversations with industry representatives, EPA also evaluated age of the existing
facility as a possible basis for Subcategorization. EPA determined that the age of a
facility is not an appropriate measure for Subcategorization. Electric generators often add
new generating units and may then retire older, less-efficient units. As such, the date at
which the facility began operations may not be reflective of a facility's current
operations.
However, EPA does recognize that many existing power plants and manufacturing
facilities operate older units; as noted in Chapter 4, over 31 percent of coal-fired
generating units are more than 50 years old. As a result, it may be undesirable to retrofit
some older facilities to closed-cycle cooling, as these facilities may be approaching the
end of their useful life.
5.3 Processes Employed
5.3.1 Electric Generators
The major difference between power plants in terms of "process" is the fuel source. As
illustrated in Chapter 4 of the TDD, power plants use a variety of fuels to generate
electricity.
Exhibit 5-1 shows the typical generating efficiencies for each fuel type.
Exhibit 5-1. Generating Efficiency by Fuel Type
Fuel Type
Coal
Natural Gas
Nuclear
Typical Plant Efficiency (%)
32-42
32-38
38
In general, the type of fuel used at a facility generally does not affect the design or
operation of the facility's CWIS. The type of fuel may affect the volume of water
needed, additional design considerations (e.g., emergency backup withdrawal
5-2
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
capabilities), or other elements of the facility's operation, but these elements generally do
not impact the selection or operation of intake technologies. l
EPA also explored the thermal (fuel) efficiency of different fuel types as a basis. While
many reviews identify nuclear as far less efficient than coal, these comparisons do not
factor in the significant heat losses from the stack of coal-fired units. When this source of
heat is accounted for, there is no discernable difference in thermal efficiency by fuel type.
Based on discussions with industry during site visits, one of the main differences related
to fuel type is intake flow for nuclear facilities. In order to more fully explore the
assertion that nuclear facilities exhibit different trends in the utilization of cooling water,
EPA plotted the cumulative intake flow for nuclear and non-nuclear facilities. Exhibits
5-2 and 5-3 below illustrate the flow data by non-nuclear facilities and nuclear facilities,
respectively.
Exhibit 5-2. Distribution of Intake Flows for All Non-Nuclear Electric Generators
=:>:
H:=:
TBS
= :>:
r
4SB7
DIP FlowThresholdl |BGD;
1 Note that, where necessary, EPA has incorporated fuel type-based costs in determining the compliance
costs for facilities. For example, downtime estimates for nuclear facilities are substantially longer than
those for fossil fuel facilities.
2 See discussion in Section 2.6.1 for information on how EPA created the graphs.
5-3
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-3. Distribution of Intake Flows for All Nuclear Electric Generators
r:>;
= :>•,
-:-•,
=C»>
- 43—i 2M
DIP Flow Threshcld((EGD]
These exhibits show that nuclear electric generator facilities on average have a larger
flow than non-nuclear electric generators, which affects the size of the cooling system.
However, EPA did not identify significant differences in CWIS technologies between
nuclear and non-nuclear facilities and, therefore, this was not determined to be an
appropriate basis for Subcategorization.
EPA data also indicate that the distribution of nuclear facilities versus non-nuclear
facilities does not differ significantly by waterbody type (see Exhibit 5-4).
Exhibit 5-4. Distribution of Nuclear and Non-Nuclear Facilities by Waterbody Type
Waterbody Type
Freshwater River or Stream
Tidal River or Estuary
Lake or Reservoir
Great Lake
Ocean
Percent of Nuclear Facilities
39.7
15.5
22.4
13.8
8.6
Percent of Non-Nuclear
Facilities
48.7
20.2
20.9
6.8
3.3
EPA data do indicate that a somewhat larger percentage of nuclear facilities use closed-
cycle cooling than non-nuclear facilities (see Exhibit 5-5). However, because the
percentage of nuclear facilities using closed-cycle cooling remains limited and the
majority of applications of closed-cycle cooling are newly built units (i.e., Palisades is the
only nuclear facility that has retrofitted to closed-cycle—see DCN 10-6888), this was not
determined to be an appropriate basis for Subcategorization.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-5. Distribution of Nuclear and Non-Nuclear Facilities by Cooling System
Type
Cooling Water System Type
Once-through
Closed-cycle
Combination or Other
Percent of Nuclear Facilities
50.0
37.9
12.1
Percent of Non-Nuclear
Facilities
78.3
12.0
9.7
5.3.2 Manufacturers
In general, manufacturers use cooling water in much the same way as electric generators.
While the end product may vary (e.g., paper products versus electricity), the cooling
water is often used for similar industrial processes. Where manufacturers differ is in their
use of contact cooling water and process water, which are typically also withdrawn from
the same intake structure as non-contact cooling water.3 Contact cooling water is mixed
directly with the product, such as quench water for a steel mill. Process water is used to
create the end product itself, such as water used in producing beverages. These two
categories of water withdrawals are distinct from non-contact withdrawals in that they are
much more difficult to reduce or eliminate without having a material effect on the end
product. In other words, flow reduction (such as the use of closed-cycle cooling) is not
likely to be a viable alternative for contact cooling or process flows, as they would
adversely affect the facility's production. As a result, Options 2 and 3 (see Chapter 7 or
the preamble) excluded contact and process flows from flow reduction requirements. As
discussed in Chapter 8, EPA adjusted its cost methodology for manufacturers to account
for this difference; intake flow rates (the basis for cooling tower costs) at manufacturing
facilities were adjusted by as much as 47 percent.
Additionally, as shown in Chapter 4, manufacturers use essentially the same intake
technologies and cooling system types as electric generators. As a result, there is no data
suggesting that manufacturers should be addressed separately on the basis of intake or
cooling system technologies.
5.4 Existing Intake Type
As illustrated in Chapter 4, existing facilities use a variety of intake locations, designs,
and technologies for withdrawing cooling water. While a facility's site-specific
characteristics will have a significant impact on the facility's choice for its intake location
(e.g., shoreline, offshore, etc.) and the selection, design, and operation of the facility's
intake technology, generally any of the possible intake locations will be able to supply
sufficient cooling water to a facility. In addition, the various types of intake
configurations (e.g., canal, surface, sub-surface, infiltration, sequenced intakes such as an
intake emptying into a forebay) were not, by themselves, found to affect BTA. As such,
EPA determined that it could not establish any appropriate subcategories based on the
existing intake type.
Electric generators use non-contact cooling water almost exclusively. As a result, no analysis of contact
or process water is required for power plants.
5-5
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Chapter 5: Subcategorization § 316(b) Existing Facilities Proposed Rule - TDD
In general, the intake type does not affect a facility's ability to retrofit closed-cycle
cooling; the existing intake structure will have more than enough capacity to sustain the
reduced level of water withdrawals. Therefore, EPA did not consider intake type as a
factor in studying entrainment mortality requirements. Intake type may, however, affect
impingement mortality requirements. Where appropriate, EPA's compliance costs reflect
the existing intake location and the presence of existing intake technologies. As
discussed in Chapter 8, facilities with technologies deemed to be compliant with the
impingement mortality requirements of the proposed rule are not assigned any
compliance costs. Technologies are, in part, assigned based on intake location, in order
to facilitate the most cost-effective compliance solution. Other facilities will be required
to upgrade, as reflected in the assigned technology costs.
5.5 Application of Impingement and Entrainment Reduction
Technologies
The proposed rule and record identifies several impingement and entrainment reduction
technologies in various categories, including flow reduction, closed-cycle cooling,
screens, diversions, barriers, fish returns, behavioral systems, velocity reduction, physical
configurations, and location. However, except for flow reduction, EPA has not identified
data that indicate that a specific impingement and entrainment reduction technology is
most effective for a particular segment of facilities. Rather, the data indicate that
effective technologies can be applied in a variety of settings and that facilities typically
use these technologies based on an appropriate configuration for the relevant facility.
Thus, the available data does not support Subcategorization based on particular
impingement and entrainment reduction technologies already in place.
5.6 Geographic Location (including waterbody category)
Existing facilities are located throughout the United States (see Exhibit 4-2 in Chapter 4),
operate in a variety of climatic, geologic, and hydrologic regimes, and are located in a
range of populated areas from urban to rural. While the local conditions may affect how
often a facility operates, its operational requirements, and the maintenance procedures
necessary to operate efficiently, facilities are well-accustomed to these site-specific
conditions and have incorporated these factors into their daily operations.
Geographic location can affect the physical and biological setting of a CWIS, however,
EPA has not identified general trends that would allow the agency to use geographic
location as a basis for Subcategorization (i.e., EPA has not identified locational factors
that affect the efficacy or availability of the primary technologies that may comprise
BTA). Rather, the data indicate that effective technologies can be applied in a variety of
settings and that facilities typically use these technologies based on an appropriate
configuration for the relevant facility. EPA notes that it has included "regional cost
factors" that adjusts model facility costs based on the model facility's location to account
5-6
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 5: Subcategorization
for local conditions.4 As discussed in the EA, EPA has also analyzed the impacts of the
proposed rule on the reliability of regional power production.
EPA also considered waterbody category as a possible basis for Subcategorization. As
illustrated in Chapter 4 of the TDD, facilities are located on a variety of waterbody types.
In the Phase I rule, certain waterbody types were required to meet design and operational
criteria.5 In the 2004 Phase II rule, EPA established different performance requirements
based in part on a facility's location on different waterbody categories.6 That approach
was based on the general characteristics of the waterbody categories and of groups of
aquatic organisms. However, in the proposed rule, EPA is not differentiating between
waterbody types; all facilities are required to meet the same impingement mortality and
entrainment mortality requirements. This approach is based on the study data being used
to establish BTA and the fact that these data do not reflect as clear a distinction between
waterbody categories as was used in 2004. Specifically, the characterization data show
the range of organism densities between waterbody types overlap. (See DCN 10-6711
for more information.)
Further, the density of organisms may not be a key factor in assessing adverse
environmental impact. For example, some organisms are broadcast spawners and others
are nest-builders. A single egg in a freshwater system may be more important to that
ecosystem than a single egg in a marine system.
In the absence of actual data that clearly establishes distinctions among waterbody
categories, EPA has determined that it could not establish any appropriate subcategories
based on waterbody type and that it is prudent to provide a consistent level of protection
to aquatic organisms affected by CWISs.
5.7 Facility Size
EPA evaluated multiple metrics in analyzing facility size for existing facilities: intake
flow and electricity output.
5.7.1 Intake Flow
First, EPA examined the universe of electric generators for trends in intake flows. EPA
recognizes that intake flow volume is an important element in determining impingement
and entrainment and it is, therefore, logical to examine intake flow as a means for
Subcategorization.
4 For example, facilities located near the Great Lakes are allotted an increased cost for managing zebra
mussels.
5 For example, facilities are not permitted to withdraw more than 1 percent of the tidal excursion. See 40
CRR 125.84(b)(3)(iii).
6 Facilities located on estuaries, tidal rivers, Great Lakes, and oceans were subject to more stringent
requirements. See 40 CFR 125.94(b)(l) and (2).
7 Often, marine organisms are broadcast spawners while freshwater organisms are nest-builders or deposit
eggs in specific locations.
5-7
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Industry uses multiple metrics for intake flow: design intake flow (DIP), actual intake
flow (AIF), and nameplate capacity. Design intake flow reflects the value assigned
during the cooling water intake structure design to the maximum volume of water the
cooling water intake system is capable of withdrawing from a source waterbody over a
specific period of time. Actual intake flow is the average flow actually used over a
specific period of time. Nameplate capacity is the amount of electric power delivered or
required for which a generator, turbine, transformer, transmission circuit, station of
system is rated by a manufacturer (this capacity is then correlated with required flow).
EPA compiled the design intake flow (DIP) information from the industry questionnaires
for all electric generators in ascending order and calculated the percent of flow captured
by various flow thresholds (see Exhibit 5-6 through 5-10). To allow for the inclusion of
closed-cycle facilities in this analysis EPA first needed to normalize the design intake
flow (DIP) for each facility with closed-cycle cooling to a comparable DIP that would be
utilized by the facility if it employed a once-through cooling system.8 For facilities that
utilize a combination cooling system (i.e., part once-through and part closed-cycle), EPA
reviewed the industry surveys to determine the proportion of the DIP that would be
converted.9
Exhibit 5-6 shows all electric generators plotted in ascending order by normalized DIP.
Exhibit 5-6. Normalized DIF at Phase II and III Electric Generating Facilities
300 400
Facilities in Ascending Order
8 For this analysis, EPA assumed that facilities using cooling towers and located on marine waters
experience an 80 percent reduction in flow and facilities on fresh water experience a 95 percent reduction
in flow. To approximate the facilities once-through "assumed DIF," its DIF using the closed-cycle system
was increased accordingly. Note that EPA has since revised its estimates for the percent reduction in flow,
particularly on marine waters.
9 In some cases, facilities use helper cooling towers, cooling lakes, or other configurations that are, for the
purposes of this analysis, essentially once-through cooling. EPA did not adjust these flows.
5-8
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
As shown by this plot, approximately 75 percent of these facilities have DIFs less than 1
BGD and approximately 95 percent of facilities have DIFs less than 2BGD.
Exhibits 5-7 through 5-12 present the distribution of DIF and AIF (normalized and non-
normalized) flows across several criteria, as well as the distribution of nameplate
generating capacity across normalized DIF. Specifically,
• Exhibit 5-7 presents the percent of normalized DIF, normalized AIF, non-
normalized DIF, non-normalized AIF and total facilities captured relative to DIF
in billion gallons per day;
• Exhibits 5-8 through 5-11 present the percent of normalized and non-normalized
DIF and AIF across waterbody categories (FWR - freshwater rivers and streams;
TR&E - tidal rivers and estuaries; Oceans; GL - Great Lakes; and all facilities)
relative to DIF in billion gallons per day; and,
• Exhibit 5-12 presents the distribution of nameplate generating capacity across
normalized DIF.
Exhibit 5-7. Distribution of Intake Flows for All Electric Generators
100% i
M
1
^-^^'•- z_
/ sir
• r
-------
Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-8. Distribution of Normalized DIF for All Electric Generators
30% .
4-1
c
9
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*
123456789
DIF Flow Threshold (BGD>
— * — FWR normalized
DIF
— • — TR&E normalized
DIF
A Ocean normalized
DIF
— * — L&R normalized
DIF
X GLnormalizedDIF
—•—All facilities
normalizedDIF
Exhibit 5-9. Distribution of DIF (Non-Normalized) for All Electric Generators
100% -1
53
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/////-
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1234557B9
DIF Flow Threshold (BGD)
— *— FWRDIF
— •— TR1EDIF
-+- C-:=srDIF
^<— LS.RDIF
— *— QLDIF
— •— Allfacililies DIF
These exhibits show that the distribution of flow and facilities are generally similar
across waterbody categories, although ocean facilities appear to use somewhat larger
flows. The non-normalized data also reflect greater variation than the normalized data
although the general distributions are similar.
5-10
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-10. Distribution of Normalized AIF for All Electric Generators
100%
70% -
^ DU^O
c
a
o
Q-
40% -
^^ —
J&7/
]ff
/ /
/// /
w~/_
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1234567S9
DIP Flow Threshold (BGD)
— * — FWR normalized
AIF
— • — TR&E normalized
— * — Ocean normalized
AIF
— ^ — L&R normalized
AIF
X GL normalized AIF
—*— All facilities
normalized AIF
Exhibit 5-11. Distribution of AIF (Non-Normalized) for All Electric Generators
4567
DIP Flow Threshold (BGD)
FWRAIF
All facilities AIF
The AIF data do not show dramatic variation when compared with the DIP data for these
plots. One difference is that 90 percent or greater of AIF is captured at a lower facility
DIP threshold.
5-11
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-12. Distribution of Nameplate Generating Capacity
Ascending Normalized DIP
Exhibit 5-12 shows a general and somewhat variable correlation between DIP and
electrical power output, and also indicates that some facilities, most likely more efficient
operations, are able to produce a range of power at a lower DIP. However, such
production is not correlated with CWIS technologies and the proposed rule includes a
generally applicable compliance alternative that promotes reductions in cooling water
intake flow.
Exhibits 5-13 through 5-15 show the percentage of facilities (electric generator and
manufacturer separately, and then all facilities) and the total DIP and AIF that would be
addressed by various flow thresholds.
5-12
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-13. Electric Generators and Flow Addressed By Various Flow Thresholds
100%
80%
Percen
40%
2 20 50 80 100 150 250 500 1000 2000
DIP Threshold (MGD)
•Generators
Above
Threshold
DIP Below
Threshold
•Generator
AIF Below
Threshold
Exhibit 5-14. Manufacturers and Flow Addressed By Various Flow Thresholds
0%
2 20 50 80 100 150 250 500 1000 2000
•Manufacturers
Above
Threshold
• Manufacturer
DIP Below
Threshold
DIP Threshold (MGD)
5-13
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-15. Facilities and Flow Addressed By Various Flow Thresholds
Percent
1 niw ™
Qfl°/£
SfW
7fW
fin%
c;fw
An%
3fW
9n%
10%
0% -
• Percent of
Facilities Above
Threshold
^^Percent of DIP
Below
*s _
. •fr •
X * ' * "
2 20 50 80 100 150 250 500 1000 2000
DIP Threshold (MGD)
5.7.2 Generating Capacity
EPA also considered generating capacity as an aspect of facility size. Exhibit 5-12 above
presents generating capacity plotted against normalized DIP and Exhibit 5-16 below
presents generating capacity plotted against non-normalized DIP.
Exhibit 5-16. Distribution of Nameplate Generating Capacity
4500
4000
3500
3000
2500
2000
1500
1000
500
Ascending DIP
5-14
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 5: Subcategorization
Exhibit 5-11 shows a similar pattern to Exhibit 5-10, with greater scatter of facilities,
which suggests that closed-cycle cooling provides a range of flow reduction that is
dependent on numerous factors.
As illustrated by the exhibits above, there are no clear trends for electric generating
facilities based on intake flow relative to waterbody type or generating capacity. As
such, EPA determined that it could not establish any appropriate subcategories based on
any of those categories.
5.8 Non-Water Quality Environmental Impacts
New or additional intake technologies will not lead to unusual non-water quality
impacts.10 Many of the technologies discussed in the proposed rule are already in use at
many facilities and do not fundamentally change the operation of intake technologies as a
whole. EPA recognizes that requiring facilities to retrofit to closed-cycle cooling may
incur additional non-water quality impacts that are not insignificant. These impacts are
part of the reason that EPA did not propose to use closed-cycle cooling as the basis for
BTA for this national rule. EPA did not identify any other significant non-water quality
environmental impacts resulting from the engineering aspects of control technologies that
provide a basis for establishing appropriate subcategories.
5.9 Other Factors
EPA conducted a series of additional analyses of existing facilities in order to attempt to
determine if any additional subcategories were appropriate.
5.9.1 Capacity Utilization
EPA reviewed data on the capacity utilization rate (CUR) for Phase II facilities11 using
I r\
information from EPA's E-GRID database. In order to best match the technology data
from EPA's industry survey, EPA used the CUR data from the year 2000. Specifically,
EPA compared the CUR data against data for fuel type (by individual generating unit and
by facility), prime mover, total generating capacity (by individual generating unit and by
facility), facility age, and waterbody type. As shown in Exhibits 5-17 to 5-23 below,
there are no clear trends in any of these analyses that indicate that BTA should be
different based on low usage. As such, EPA determined that it could not establish any
appropriate subcategories based on capacity utilization.
10 See Chapter 10 for a complete discussion of the non-water quality impacts.
11 The analysis was not repeated to incorporate Phase III facilities, as the distribution of facilities among
capacity utilization rate, fuel type, and waterbody type is relatively consistent between the two groups.
12 CUR was a factor in the 2004 rule and was considered in the proposed rule.
5-15
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-17. Cumulative Distribution of Phase II Facility Year 2000 Generating
Unit Capacity Factors by Primary Fuel Type
¥ " / "
f f /
-COAL (523}
-GAS (404)
-SOLID WASTE®
-NUCLEAR (9)
-OIL{143)
-WASTE HEAT (27)
»5% 9O% 95% 100%
Exhibit 5-18. Distribution of Phase II Facility Year 2000 Generating Unit Capacity
Factors by Generating Unit Prime Mover
BOX
I 30%
•s
H 2°%
1
«£ •:==
z
5% 10% 15% 20% 25% 53% 35% 40% 45% 50% &3% 70% 80% 90% 100%
Capacity Factor
-•-Steam (1266}
-*-3as Turbine {79>
a< Combings cyctesfean turbine wilti supplanen&ry firing(tS)
-1 mental CombusSon (12)
-Com bii>ed cysfe combuslian tiflbm
5-7(5
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-19. Phase II Facility Year 2000 Generating Unit Capacity Factors Versus
Nameplate Generating Unit Capacity
Generating Capacity (MW)
Exhibit 5-20. Phase II Facility Generating Unit Year 2000 Capacity Factor Versus
Year Generating Unit Came Online
0%
-10%
2005
Year Generating Unit Online
5-77
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-21. Distribution of Phase II Facility Year 2000 Total Plant Capacity
Factors by Primary Fuel Type
Capacity Factor
NU CLEAR (5BJ-X-OIL (33} -ME- SOLID WASTE ® — 1— ALL^1}]
Exhibit 5-22. Distribution of Phase II Facility Year 2000 Total Plant Capacity
Factors by Intake Waterbody Type
Capacity Factor
= (43}
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-23. Phase II Facility Year 2000 Total Plant Capacity Factor Versus Total
Generating Capacity
•G
s.
CO
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0 500 1000 1500 2000 2500 3000 3500 4000 4500
Generating Capacity (MW)
* Nameplate Generating Capacity
5.9.2 CUR Versus DIP
EPA also examined the relationship between the design intake flow (adjusted for closed-
cycle cooling, as described above) and the CUR for Phase II facilities. As shown in
Exhibit 5-24 below, there is no clear relationship between a facility's size (i.e., DIP) and
it's frequency of operation. As such, EPA determined that it could not establish any
appropriate subcategories based on the relationship of CUR and DIP.
5-19
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 5-24. Distribution of Capacity Utilization
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5.9.3 Low Capacity Utilization Compared With Spawning Seasonality
In the 2004 Phase II rule, facilities with a CUR below 15 percent were not required to
meet entrainment requirements. As discussed in the preamble for the 2002 proposed rule
(see 67 FR 17141/1), EPA believed (at that time) that the reduced level of operations at
these facilities would provide ample protection for aquatic organisms due to a substantial
reduction in intake flows on an annual basis.
However, the proposed rule does not employ the same approach, as all facilities are
required to meet impingement mortality and entrainment standards as applicable. EPA
has changed its approach because low CUR facilities, while they do offer reduced flows
on an annualized basis, typically operate at or near their full design capacity when they
are in operation. If these periods of activity coincide with periods of high biological
value (such as a spawning period), then these low CUR facilities may be having as much
impact on aquatic organisms as a facility that operates more frequently.
EPA reviewed the group of facilities with a CUR below 10 percent (38 facilities13) and
compared the operational periods of these facilities14 to key biological periods for fish
species in the source waterbodies for these facilities. As expected, low CUR facilities are
most active in the summer and winter, when electricity demand is generally highest.
; These 38 facilities represent approximately 5.4 percent of the total DIP of Phase II facilities.
' Derived from monthly flow data from the industry questionnaire.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
Exhibit 5-25. Facilities with CUR Less Than 10 percent
Facility Name
Conners Creek
Marysville
Oswego
Edgewater
Honolulu
Zuni
Atkinson
Plant Crisp
Collins
Peru
Kaw
Monroe
Austin DT
Fox Lake
M L Hibbard
Hawthorn
Burlington
Piqua
Delaware
Schuylkill
Lake Pauline
North Texas
Sam Rayburn
Blackhawk
Menasha
Rock River
Riverside
Kearny
Linden
Sayreville
Sewaren
Indian Point
Hookers Point
Mason Steam
Henry D King
Indian River Plant
McManus
Riverside
State
Ml
Ml
NY
OH
HI
CO
GA
GA
IL
IN
KS
LA
MN
MN
MN
MO
NJ
OH
PA
PA
TX
TX
TX
Wl
Wl
Wl
MD
NJ
NJ
NJ
NJ
NY
FL
ME
FL
FL
GA
GA
Waterbody Region1
Great Lakes
Great Lakes
Great Lakes
Great Lakes
Hawaii
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Inland
Mid-Atlantic
Mid-Atlantic
Mid-Atlantic
Mid-Atlantic
Mid-Atlantic
Mid-Atlantic
Gulf of Mexico
North Atlantic
South Atlantic
South Atlantic
South Atlantic
South Atlantic
Waterbody Type2
Great Lakes
Great Lakes
Great Lakes
Great Lakes
Ocean
Freshwater River/Stream
Freshwater River/Stream
Lake/Reservoir
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Lake/Reservoir
Lake/Reservoir
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Freshwater River/Stream
Lake/Reservoir
Lake/Reservoir
Freshwater River/Stream
Freshwater River/Stream
Lake/Reservoir
Freshwater River/Stream
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
Estuary/Tidal River
1 In this context, "region" is defined as the fisheries region used in the national benefits analysis in the EEBA.
2 Waterbody type is a regulatory classification under the 2004 Phase II rule.
EPA then examined the spawning periods of common fish species in each region of the
country. (See DCN 10-6702.) Since the facilities with a low CUR do not show any
regional or geographic trends (i.e., no one region has disproportionately more low CUR
facilities), it is reasonable to conclude that a broader review offish species by region will
5-21
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
adequately address the correlation between spawning season and CUR. Two conclusions
are apparent:
• For many waterbodies, there are few periods in the year when there is an absence
of spawning activity, indicating that facility operations at any time of the year
could have an impact on aquatic organisms.
• The operational periods of many low CUR facilities coincide with spawning
periods of nearby fish species.
As such, EPA determined that low CUR facilities should not necessarily be exempted
from entrainment requirements.
5.9.4 Fish Swim Speed
The swimming ability offish is one key component in reducing impingement (and
therefore impingement mortality). EPA reviewed data from an Electric Power Research
Institute (EPRI) study on fish swim speeds (see DCN 2-028 A) to determine if there was
any difference in the swimming abilities offish in different waterbodies. As shown in
Exhibit 5-26, assemblages offish in the various waterbodies did not demonstrate any
clear superiority in swimming ability. As such, EPA determined that it could not
establish any appropriate waterbody-based subcategories based on the fish swim speed in
those waterbodies.
Exhibit 5-26. Swim Speed Versus Fish Length
10
20
30 40
Fish Length (cm)
50
60
70
5-22
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 5: Subcategorization
5.9.5 Water Use Efficiency
EPA also analyzed power generating facilities' cooling water withdrawals and electricity
generated as a measure of how efficient a given facility is in its use of cooling water.
Initially, EPA examined the design intake flow for facilities above 50 MGD and
compared it to their steam generating capacity as a way to identify the least efficient
facilities. Exhibit 5-27 shows the results of this analysis, with cooling ponds sites
identified separately.
Exhibit 5-27. Design Intake Flow (gpm) / MW Steam Capacity for Once Through
Power Plants Over 50 MGD
5
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DIP (GPD)
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•Old DUT1 275
Pond Facilities
00
EPA expanded upon this analysis by using data from the industry surveys (actual intake
flow) and compared it to the electricity generation from the corresponding period.
Facilities were then sorted based on the calculated ratio of water use per megawatt
generated. Exhibit 5-28 shows the median ratio for facilities with various cooling system
types (once through, closed-cycle, combination, and combined cycle15). EPA examined a
range of analyses for water use efficiency, including variants that excluded facilities that
utilize closed-cycle cooling, as these facilities clearly withdraw less water per megawatt
than once through facilities. Exhibit 5-28 shows the median efficiency for each type of
facility, with a variety of horizontal lines that represent various thresholds; for example,
the top 10 percent most efficient power plants (including closed-cycle)) have
approximately the same efficiency as closed-cycle systems, while the same ratio drops
The increased generating efficiencies of combined cycle plants warranted their separation into a different
grouping.
5-23
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Chapter 5: Subcategorization
§ 316(b) Existing Facilities Proposed Rule - TDD
significantly when closed-cycle systems are excluded. See Chapter 7 for more discussion
of how EPA considered this information.
Exhibit 5-28. Median Water Efficiency (Water Use per MW Generated) of Power
Plants (Including CCRS)
Median Water Efficiency (Water Use per MW Generated) of Power Plants
Top 10% of all plants
[including CTs)
i op J.u7o OT an piams
(excluding CTs}
Top quartile of all plants
(including CTs)
Top and bottom quartile of
each facility type
Median of all plants
(including CTs)
Once-through Natural Gas Combined Combination Cooling Closed-cycle Recirculating
Cycle System /Cooling Towers
5.9.6 Land Availability
While EPA believes that the vast majority of facilities have adequate available land for
placement of cooling towers,16 some facilities may have legitimate feasibility constraints.
Based on site visits, EPA has found several facilities have been able to engineer solutions
when faced with limited available land. EPA attempted to determine a threshold of land
(one option explored a threshold of approximately 160 acres per gigawatt) below which a
facility could not feasibly install cooling towers.1? Based on such an approach, EPA
projected an upper bound of 25 percent of facilities that may have insufficient space to
retrofit to cooling towers. While EPA estimated that some facilities would not have
enough space, EPA found some facilities with a small parcel of land were still able to
install closed-cycle cooling by engineering creative solutions.18 On the other hand, EPA
found that some facilities with large acres still could not feasibly install cooling towers
due to, for example, protected wetlands. While EPA was able to account for space
constraints in its estimated compliance costs (see Chapter 8), there was not enough data
to make a site-specific assessment of available land. As a result of the huge uncertainty
16 In the case of fossil fuel plants, scrubber controls may also be newly required to comply with air rules
and standards.
See DCNs 10-6671 and 10-6672.
Facilities could also build cooling towers in elevated locations, such as building roofs but this is more
expensive and is not feasible for many facilities.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 5: Subcategorization
surrounding EPA's data and analysis of available space, EPA rejected land availability as
a potential subcategory.
5.9.7 Other Factors
EPA also explored, in varying degrees of depth, and ultimately rejected a number of other
potential approaches to subcategories. These analyses included an evaluation of creating
subcategories based on the following:
• Similar groups offish species (see DCN 10-6704)
• Spawning period (see DCN 10-6702)
• Deep offshore intake location (See Chapter 12)
• Combined cycle (see DCN 10-6631)
• Cogeneration (see DCN 10-6630)
• Dry cooling (see DCN 10-6679)
• 7Q10 of the source waterbody
• Flue gas desulphurization (see DCN 10-6681)
Because these factors were only applicable to a limited number of facilities, EPA found
these factors would not improve setting and implementing national performance
standards.
5.10 Conclusion
As shown in the analyses above, EPA has examined numerous aspects of existing
facilities, including both production-related and CWIS-related characteristics, and has
determined that although these facilities exhibit a range of characteristics, these
characteristics do not differ to the extent that different technologies are most effective or
uniquely available to distinct subcategories of facilities. EPA's analysis demonstrates
that several CWIS technologies are effective for existing facilities and that these
technologies do not differ significantly across the various subcategory criteria considered.
Therefore, EPA is not establishing any subcategories for the proposed rule.
Although no subcategories are being proposed, the rule does reflect the key factors and
variability that are relevant to CWIS impacts. The proposed rule would establish basic
standards for the reduction of impingement mortality and entrainment. It also provides
several compliance alternatives that reflect technologies that can be used to minimize
adverse impacts and that are to be implemented on a case-by-case basis in accordance
with the characteristics of a specific facility (e.g., location, size, existing technologies,
etc.). In this way, the structure of the proposed rule is consistent with the data identified
for existing facilities.
5-25
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 6: Technologies and Control Measures
Chapter 6: Technologies and Control Measures
6.0 Introduction
In developing the 2004 Phase II rule and 2006 Phase III rule, EPA conducted a
comprehensive review of technologies that reduce impingement and entrainment (I&E) at
cooling water intake structures.l For the proposed Existing Facilities rule, EPA
reconsidered existing information on these technologies, identified new technologies, and
updated efficacy information based on new study data. This chapter describes the
primary technologies and operational measures considered in developing requirements
for the proposed rule. Each section provides an overview of the technology, a discussion
of performance in reducing impingement and/or entrainment, and examples of facilities
and/or laboratory studies that employ the technology.
In general, technologies and control measures can be divided into two major groups: flow
reduction and screening or exclusion. Flow reduction is the clearest way to reduce I&E,
as lower intake flows will impinge and entrain fewer organisms, generally in proportion
to the amount of flow reduction. Screens act to exclude organisms from the intake
structure and return them to the source waterbody. Exhibit 6-1 lists the technologies and
control measures discussed in this chapter.
In addition to this chapter, the Electric Power Research Institute's (EPRI) 2007 Fish
Protection at Cooling Water Intakes: A Technical Reference Manual (DCN 10-6813) is a
compilation of studies conducted at various sites throughout the country and serves as a
comprehensive reference for cooling water intake technology performance. For a
discussion of cooling tower technologies and retrofit issues, see Chapter 8 of EPRI
(2007) and the California Ocean Protection Council's California's Coastal Power Plants:
Alternate Cooling System Analysis (DCN 10-6964). EPRI has also released a preliminary
document which quantifies environmental and social effects of conversions to closed-
cycle for seven facilities, Net Environmental Effects of Retrofitting Power Plants with
Once-Through Cooling to Closed-Cycle Cooling, May 2008 (DCN 10-6926 and 10-
6927).
In general, all of the technologies presented in this chapter can be effective and are
equally available at both power plants and manufacturers, as well as for existing facilities
and new facilities. Cooling water intake structures are a technical apparatus that is
designed to supply water; the end use of the water is of little importance when evaluating
the CWIS's effectiveness or the feasibility of a given technology. There will certainly be
site-specific factors that weigh heavily in evaluating technologies but the type of
"downstream" user is generally not relevant. In the case of manufacturers, there are
greater opportunities for flow reduction and reuse of cooling water.
1 See Chapter 3 of the 2002 Phase II proposed rule (DCN 4-0004), Chapter 4 of the 2004 Phase II final rule
TDD (DCN 6-0004), and Chapter 8 of the proposed Phase III rule (DCN 7-0004).
2 See Chapter 2 of the TDD for a discussion of data collection efforts.
6-1
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Chapter 6: Technologies and Control Measures
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 6-1. List of Technologies Considered
Flow Reduction Technologies and Control Measures
Closed-cycle recirculating systems
Wet cooling systems
Dry cooling systems
Variable speed pumps/variable frequency drives
Seasonal flow reductions
Water reuse
Alternate cooling water sources
Screening Technologies
Conventional traveling screen
Modified coarse mesh traveling screen
Geiger screen
Hydrolox screen
Beaudrey W Intake Protection (WIP) screen
Coarse mesh cylindrical wedgewire screen
Barrier net
Velocity cap
Fine mesh traveling screen
Fine mesh wedgewire screen
Aquatic filter barrier
Other Technologies and Operational Measures
• Reduced intake velocity
• Substratum intakes
• Louvers
• Intake location
6.1 Flow Reduction Technologies and Control Measures
This section describes technologies and control measures used to reduce cooling water
intake flows. By reducing the intake flow, a facility can reduce its I&E; impingement is
related to intake flow (among other variables and entrainment is directly proportional to
flow. The largest reductions are usually realized by installing (or retrofitting) a closed-
cycle recirculating cooling system but facilities may also employ variable speed pumps,
seasonal flow reductions, water reuse, or use of alternate sources of cooling water.
6.2 Closed-Cycle Recirculating Systems
Closed-cycle cooling systems transfer a facility's waste heat to the environment and
recycle the cooled water back to the condensers to be used again. These recirculating
systems enable a facility to withdraw significantly smaller quantities of (or in some cases
no) surface water. Closed-cycle cooling systems include cooling towers and cooling
lakes/ponds.3 Cooling towers are structures that recirculate water within the cooling
system, while providing for the exhaust of excess heat. Towers are generally of two
designs: mechanical draft, in which heated water is exposed to air currents driven by
3 Note that the term "cooling pond" is often used or defined broadly, but under the proposed rule, not all
cooling ponds are considered to employ closed-cycle cooling. See the preamble to the proposed rule and
Chapter 3 of the TDD for additional discussion.
6-2
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 6: Technologies and Control Measures
electrical fans, or natural draft, in which heated water is allowed to interact with naturally
induced drafts within the tower. In both cases, water within the cooling system is cooled
and sent back to the condenser to be used again. Approximately 28 percent of existing
power producers and 35 percent of existing manufacturers use recirculating systems
(cooling towers).
Due to the evaporative processes involved (and the subsequent buildup of dissolved
solids), cooling towers require that a certain portion of the circulating water be
discharged (as "blowdown") and replaced (makeup water).4
Cooling ponds are surface waterbodies that serve as both a source of cooling water and a
heat sink. As with cooling towers, cooling ponds rely on evaporative cooling to dissipate
the waste heat. Depending on local hydrology, cooling ponds may also require makeup
water from another waterbody (the level of makeup water depends on numerous site-
specific factors including size, inflow and outflow, and evaporation; EPA has not
identified a source of data that describes cooling pond makeup flows). At many facilities,
cooling ponds have evolved into more than part of an industrial waste treatment process,
as recreational fishing and other designated uses have been established.
There are two main types of cooling towers, wet cooling and dry cooling. Each of these
technologies is described below.
6.2.1 Wet Cooling Systems
In a wet cooling system, waste heat is primarily transferred through evaporation of some
of the heated water into the surrounding air.5 This process enables a facility to re-use the
remaining water thereby reducing the quantity of water that must be withdrawn from a
water body. While the amount of water withdrawn from the water source is greatly
reduced, it is not eliminated completely because make-up water is required to replace
water lost through evaporation. There are two main types of wet cooling systems:
natural draft and mechanical.
A natural draft cooling tower is tall, up to 500 feet or more, and has a hyperbolic shape
which resembles a wide, curved smoke stack (see Exhibit 6-2). The height of these
towers creates a temperature differential between the top and bottom of the tower,
creating a natural chimney effect. Unlike natural draft towers, mechanical cooling towers
rely on motorized fans to draw air through the tower and into contact with the heated
water. These towers may be much shorter than natural draft cooling towers, typically
ranging from 30 to 75 feet in height (see Exhibit 6-3), but may require more land area and
reduce a facility's net generating output due to the electricity required to operate the fans.
Both natural draft and mechanical cooling towers can operate in freshwater or saltwater
environments. Saltwater applications typically require more make-up water than
freshwater applications, making them less efficient in reducing water withdrawals.
4 The frequency at which blowdown occurs depends on the source waterbody; fresh water requires less
frequent blowdown than brackish water.
5 In addition, a smaller portion of the heat is also removed through direct contact between the warm water
and the cooler surroundings.
6-3
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Chapter 6: Technologies and Control Measures
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 6-2. Natural draft cooling towers at Chalk Point
Generating Station, Aquasco, MD
Exhibit 6-3. Mechanical draft cooling towers at Logan Generating Plant,
Swedesboro, NJ
6-4
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 6: Technologies and Control Measures
Cooling Tower Optimization
The use of cooling towers significantly reduces the withdrawals of cooling water, but
some make-up water is still withdrawn in wet cooling tower systems. Facilities can
optimize the reduction in flow by also minimizing the make-up flow withdrawals. The
most common concept used to describe the level of optimization is cycles of
concentration (COC). This represents the ratio of dissolved solids in the recirculated
water versus that in the make-up water. Operating at a higher COC usually requires
additional O&M, such as an increased use of chemicals.
In its analyses, EPA assumed a minimum COC of 1.5 for salt water towers and 3.0 for
freshwater towers. These levels correspond to flow reductions of 94.9 percent and 97.5
percent respectively (at a delta T of 20°F, which is common for power plants and is in the
center of the range observed by EPA). Exhibit 6-4 shows the reductions in flow for
various waterbody types, cooling system configurations and COCs; the vertical lines
represent the two COCs used by EPA in its analyses. See DCNs 10-6673 and 10-6674
for a detailed discussion of cooling tower optimization.
Exhibit 6-4. Percent Reduction in Flow for Various Cooling System Delta Ts
100
.fi
|
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£
90
g so
75
70
I—I 1—I 1—I 1—I
34567
Cycles of Concentration
10
Alternative Configurations
Modular cooling tower units provide an additional cooling tower alternative. Modular
cooling towers resemble mechanical cooling towers, but are portable, typically rented for
short-term periods and quickly assembled (see Exhibit 6-5). Modular cooling tower units
have been used as temporary replacements for existing cooling tower systems that need
major repairs, for facilities that are subject to interruptions in the ability to withdraw
6-5
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Chapter 6: Technologies and Control Measures
§ 316(b) Existing Facilities Proposed Rule - TDD
sufficient quantities of cooling water, and for facilities that require supplemental cooling
or flow reduction for only a portion of the year. EPA has determined that the use of
modular towers (on a temporary basis) could substantially reduce the effects of downtime
from retrofitting intake technologies at some facilities (see DCN 10-6677). Facilities that
would be able to install the modular towers may actually face no downtime at all, which
would eliminate a significant component of the costs of the proposed rule and replace it
with the smaller, temporary cost of modular tower rentals. (See the Environmental and
Economic Benefits Analysis for a discussion of the role of downtime costs in EPA's
estimation of national economic impacts). Because EPA was not able to estimate how
many facilities would be able to employ these modular towers, however, the Agency has
not attempted to estimate the overall cost savings of using them. As a result, EPA did not
adjust its national cost estimates to include the use of modular cooling towers.
Facilities also often utilize a "combination" cooling system, in which some portion of the
cooling system uses closed-cycle cooling.6 For example, a facility might have one unit
operating with a once-through system and a second unit has a cooling tower. For the
purposes of costing and consideration of cooling tower retrofits, EPA considered these
facilities along with facilities that are fully once-through.
Exhibit 6-5. Modular cooling tower (image from Service Tech)7
Facilities that face significant challenges in meeting thermal discharge limits may operate
"helper" cooling towers.8 These are typically mechanical draft towers that are not
associated with the cooling system itself; they simply withdraw heated effluent that is
' Approximately 8 percent of electric generators and 12 percent of manufacturers use combination systems.
http://servicetechweb.com/photo2.html
' See DCN 10-6676 for a detailed discussion of helper towers.
6-6
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 6: Technologies and Control Measures
discharged by the facility, evaporate heat, and return the water to the discharge point.
These systems do not reduce the overall intake flow. Harllee Branch is an example of
such a facility (See DCN 10-6537 for EPA's site visit report to this facility).
6.2.2 Dry Cooling Systems
Dry cooling systems completely eliminate the need for cooling water withdrawals.
Unlike wet cooling systems, in dry cooling systems, waste heat is transferred completely
through convection and radiation rather than evaporation. Dry cooling systems are in use
at a number of facilities in the United States and worldwide (See DCNs 4-4023H, 10-
6679 and 10-6943). Since 1990, dry cooling has been installed in at least one facility in
every EPA Region, with many being installed in Regions 1 and 2 (states with historically
more stringent regulatory regimes) and the west, where water resources (for once-through
or wet towers) are more limited. In the 1990s, most of the facilities that installed dry
cooling were small (less than 100MW for the dry-cooled unit). But in the past decade,
dry cooling has become more prevalent at much larger facilities, with virtually all dry-
cooled units being over 100MW and many 250MW and larger. At present, Mystic (MA)
and Midlothian (TX) are the largest known dry-cooled units, at 500MW each (out of a
pant-wide capacity of 1600MW and 1650 MW, respectively).
There are two main types of dry cooling systems: direct and indirect. Direct systems
function similar to a radiator in a car; the turbine exhaust steam passes to a fin tube array
where air is drawn across and heat is rejected ultimately producing a condensate that is
returned for reuse in the turbine. The system is completely closed to the atmosphere and
there is no contact between the outside air and the steam or the resulting condensate (see
Exhibit 6-6). Indirect dry cooling requires a cooling tower but a surface condenser is
placed between the turbine exhaust and the tower. Heat is transferred to the circulating
medium in the condenser and dispersed to the atmosphere through the tower. However,
the difference between indirect dry cooling and a wet tower is that the water is not
exposed to the outside air.9
9 Indirect dry cooling systems are substantially less efficient in rejecting heat than direct units; however,
most facilities that would choose to retrofit dry cooling would select an indirect system, as it would be able
to tie into the existing condenser at the facility.
6-7
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Chapter 6: Technologies and Control Measures
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 6-6. Dry cooling tower (image from GEM Equipment)
10
6.2.3 Performance of Cooling Towers
In the 2004 Phase II rule, EPA estimated facilities employing freshwater cooling towers
and saltwater cooling towers would achieve flow reductions, and therefore associated
entrainment and impingement mortality reductions, of 98 percent and 70-96 percent,
respectively.u At that time, EPA's record demonstrated saltwater cooling towers
typically operated at 1.1-2.0 cycles of concentration. However, more recent information
demonstrates that, as a result of advances in design and operation, saltwater cooling
towers typically operate at 1.5 cycles of concentration. See DCN 10-6964. This equates
to a 94.9 percent reduction in flow over a once-through cooling system. As such, EPA
estimates that freshwater cooling towers and saltwater cooling towers reduce
impingement mortality and entrainment by 97.5 percent and 94.9 percent, respectively.
10 http://product-image.tradeindia.eom/00208501/b/Drv-Cooling-Tower.jpg
11 As discussed in the preamble to the proposed rule, impingement mortality and entrainment reductions are
proportional to flow reductions.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 6: Technologies and Control Measures
Retrofit Applications
EPA estimated retrofit costs as described in Chapter 8 of this TDD and in the preamble.
Engineering factors affecting the retrofit from once-through systems to cooling towers
include the following:
• Availability of space nearby.
• Need to remove or demolish existing structures.
• Whether the tower site elevation is higher than the existing cooling system intake
bay so cold water can flow by gravity to the intake bay.
• Whether there are underground interferences in the path of the new circulating
water lines or at the location of the hot water sump and new circulating water
pumps.
• Whether the tower site has overhead interferences, including transmissions lines.
• Whether the tower design may have to work around excluded areas where
activities that may not be moved or blocked occur (e.g., hazardous materials
storage, large vehicle turn-around areas, and security areas).
• The degree of construction work needed to convert the existing intake to handle
the much lower intake flow volume needed for make-up water.
• How difficult it will be to tie-in the towers to the existing cooling system.
• Whether the site has unfavorable soil or geological conditions.
• Whether the site has contamination that might require remediation.
• Nuclear safety concerns.12
• Effects to manufacturing processes.
• Potential for increased water treatment and effects on facility's effluent.
• Land use or zoning conflicts.
Net construction downtimes for retrofitting to cooling towers are estimated to be
approximately four weeks for non-nuclear plants and seven months for nuclear plants (68
FR 13526). These estimates assume that the construction tie-in would be scheduled to
coincide with the plant's routinely scheduled maintenance (typically a four week outage),
thereby reducing the total length of the downtime for tie-in. See Chapter 8 for a detailed
discussion of how downtime is calculated and incorporated into the analysis of cost.
The operation of cooling towers also leads to an energy penalty; a parasitic penalty due to
operating the cooling fans and a turbine efficiency penalty based on the incremental loss
of performance due to a change in the pressure of the steam produced within the
generating unit.
12 While nuclear safety remains a paramount concern, it is less clear that retrofitting a cooling tower would
actually have any impact on the safety of the facility. Documentation submitted to the Atomic Energy
Commission from Palisades Plant (the lone nuclear facility to undergo a closed-cycle retrofit) indicates that
"[t]he existing cooling water system [...] has no safety related functions and the modified system will
likewise have no safety related functions." See DCN 10-6888B.
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As described in Chapter 10 of this TDD, non water-quality impacts may also result from
the installation of cooling towers. These impacts may include noise, plume, and salt drift.
See Chapter 10 for a discussion of these potential impacts. Cooling tower retrofits may
also infringe upon biological resources such as wetlands or manatee habitat.
Dry cooling towers (and the accompanying equipment) will generally occupy the same or
greater footprint as wet towers, potentially exacerbating any issues with available space.
Additionally, existing facilities might need to upgrade or modify existing turbines,
condensers, and/or cooling water conduit systems, which are tasks that are typically not
required for wet tower retrofits. As with wet towers, retrofitting a dry cooling tower at an
existing facility would require extensive shutdown periods during which the facility
would lose both production and revenues, and decrease the thermal efficiency of an
electric generating facility. As stated in the preamble to the 2004 Phase II rule,13 EPA
does not believe that dry cooling is a viable alternative for reducing impingement and
entrainment at a national scale; dry cooling offers substantial reductions in impingement
and entrainment (exceeding the performance of wet cooling in that regard) but with a
significantly higher cost and penalty to performance.
Four Factors To Consider In A Closed-Cycle Retrofit
As described in the preamble to the proposed rule, EPA is not proposing to require
closed-cycle cooling on a national scale; in part, this is due to the impact of four factors:
local energy reliability, air emissions permits, land availability, and remaining useful life
of the facility. These factors are discussed in detail in the preamble.
Local Energy Reliability: In its site visits, EPA identified several urban areas where the
existing transmission system may not be able to transfer sufficient electricity during
periods of extended downtime. This limitation to reliability occurs even when a surplus
of electricity can be generated within the same NERC region. For example, EPA
identified localized circumstances in Los Angeles and Chicago where an extended outage
of one or more generating units could not be readily replaced by excess capacity in
nearby areas. Currently available models such as IPM are not able to predict localized
impacts and instead are limited to measures of reserve capacity in broader geographic
regions. See the EBA for additional discussion about energy reliability.
Air Emissions Permits: Retrofitting to closed-cycle cooling results in an energy penalty,
which in turn leads to increased air emissions. Fossil-fueled facilities may need to burn
additional fuel (thereby emitting additional CO2, 862, NOx, and Hg) for two reasons: 1)
to compensate for energy required to operate cooling towers, and 2) the slightly lower
generating efficiency attributed to higher turbine back pressure. At new units, these
impacts are much less, as the design of a new cooling system accounts for these issues.
U.S. fleet efficiency will likely increase over the long term, resulting in lower base
emissions on a per watt basis, and the turbine back pressure penalty will be further
reduced resulting in lower incremental emissions. EPA is also aware that nuclear
facilities would also need to compensate for energy required to operate cooling towers
and for the turbine back pressure energy penalty. The impact of the increased emissions
13 See 69 FR 41608.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 6: Technologies and Control Measures
varies based on the local circumstances. For example, EPA's analysis suggests that
increased emissions of PM2.5 may result in difficulty in obtaining air permits in those
localities designated as non-attainment areas. For PMio, see DCN 10-6954, which states
that emissions would be approximately 60 tons per year if all drift is PMio. This
document also noted minor drift management issues onsite at facilities using salt water
cooling towers and no negative consequences off-site. See Chapter 10 of the TDD for
more information.
Land Availability: While EPA believes that the majority of facilities have adequate
available land for placement of cooling towers, some facilities may have legitimate
feasibility constraints due to small sites, existing equipment, buildings, transmission
yards, or rail lines, challenging topography or other factors. Based on site visits, EPA has
found several facilities have been able to engineer solutions when faced with limited
available land. On the other hand, EPA found that some facilities with large sites that
still could not feasibly install cooling towers due to, for example, protected wetlands. As
described in Chapter 5, EPA attempted to numerically analyze land availability but lacks
adequate data to better analyze how land constraints can be accommodated at existing
facilities.
Remaining Useful Life of the Facility: As described in Section V of the preamble,
many existing facilities have been operating for 30 to 50 years or longer. Making major
structural and operational changes (such as retrofitting to closed-cycle cooling) may not
be an appropriate response for a facility or unit that will not be operating in the near
future. The remaining useful life of many of these units is uncertain, as this relationship
is not based solely on plant age, because plant age alone does not discern those facilities
that have completed an uprate, recently repowered, or completed other major facility
modifications to individual units.
6.2.4 Examples of Cooling Towers
An estimated 374 existing facilities currently employ either a fully or partially
recirculating cooling system using wet cooling towers. EPA has identified a number of
power plants that have converted to closed-cycle recirculating wet cooling tower systems.
Many of these facilities (including Palisades Nuclear Plant in Michigan, Jefferies
Generating Station and Canadys Station in South Carolina, McDonough and Yates in
Georgia) converted from once-through to closed-cycle wet cooling tower systems after
significant periods of operation utilizing the once-through system. Another facility,
Pittsburg Unit 7, converted from a recirculating spray-canal system to a closed-cycle wet
cooling tower system. In this case, the conversion occurred after approximately four
years of operation utilizing the original design. Detailed case studies of these retrofit
efforts are found in Chapter 4 of the TDD for the 2002 proposed Phase II rule (DCN 4-
0004) and in the site visit reports available in the docket for the proposed rule.
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Additionally, Brayton Point Generating Station in Somerset MA is currently constructing
two natural draft cooling towers as part of its retrofit from once-through cooling to
closed-cycle cooling.14
As discussed in DCN 3-3029-R6 from the Phase I docket, the data from the industry
survey indicates that newer facilities and units are trending towards the use of closed-
cycle cooling.
6.3 Variable speed pumps/variable frequency drives
At their design maximum, a facility with variable speed pumps (VSPs) or variable
frequency drives (VFDs) can withdraw the same volume of water as a conventional
circulating water pump. However, unlike a conventional (i.e., single speed) circulating
water pump, VSPs and VFDs allow a facility to reduce the volume of water being
withdrawn for certain time periods. The pump speed can be adjusted to tailor water
withdrawals to suit the cooling water needs for a specific time. 5 See DCN 10-6602 for
more information.
A reduced flow volume will result in reduced O&M costs as a result of the reduction in
pump energy requirements. Depending on site-specific conditions, this reduction may
allow the facility to recover the initial capital investment sooner and produce savings
thereafter. In fact, VSPs are often employed in industrial systems solely for their
economic benefit. In the case of power plant intakes, the reduction in flow volume has
the added benefit of reducing impingement and entrainment impacts.
VSPs can be used to reduce flow volume even during periods of peak power generation,
but there are operational limitations and consequences associated with this flow reduction
technology. These limitations include:
• Inherent limits of the technology that, based on system characteristics, may
restrict pump operation to a specified flow range to prevent damage to the pump.
The system hydraulic characteristics will also affect the amount of savings in
pump energy cost;
• Limits in flow reduction associated with NPDES permit thermal discharge limits,
since a decrease in flow will result in an increase in the temperature of the
effluent;
• Economic consequences of reduced plant generation output resulting from
reduced turbine efficiency associated with higher condenser temperatures.
14 See http://www.epa.gov/ne/bravtonpoint/index.html for details.
15 Cooling systems are designed to enable the facility to meet its cooling needs at maximum operations
under adverse environmental conditions (such as a warm source waterbody). The amount of heat the
facility needs to reject is a known value; depending on several factors, the facility actually may not need to
operate its pumps at full speed; there may be an intermediate flow rate that is sufficient to remove the heat
being generated. Facilities with multiple pumps could also choose to operate fewer than normal pumps,
perhaps reducing the value of VSPs.
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The latter two limitations are more of a concern during periods when the source water is
warmer, and will also tend to limit flow reduction during periods when the system is
operating at peak capacity.
Retrofit Applications
A VSP retrofit involves replacing fixed speed intake pumps with variable speed pumps.
At a minimum, this involves the installation of a variable frequency drive (VFD) and
replacement of the pump motor, switches, and controller. In many cases, this may be all
that is needed. A variable frequency drive is an electronic device that varies the pump
motor speed by varying the electrical frequency of the AC power delivered to the pump
motor. In some cases, the existing motor may not be designed to handle the added
harmonic electric currents associated with this type of system. In such cases, the pump
motor may need to be derated (the maximum power output and flow rate is reduced) or
the motor will need to be replaced. Additionally, the pump itself may require
replacement if the existing pump hydraulic characteristics place too many limitations on
the amount of flow reduction that can be obtained. If multiple pumps are operated
simultaneously and in parallel, it is best to retrofit all of the pumps.
The use of VFDs allows the flow through the pumps to be controlled over a range of flow
volumes, thus allowing the flow volume to be tailored to the plant operating conditions.
With proper control, the effect on turbine efficiency can be minimized and the effluent
temperature can be maintained within the NPDES permit temperature limits. This allows
the facility full flexibility to effect both small and moderate flow volume reductions when
conditions allow.
During the winter months, use of flow reduction can actually result in an increase in
turbine efficiency by eliminating subcooling in the condensers. Subcooling occurs when
the steam condensate in the condenser is cooled excessively, resulting in the system's
consumption of additional heat to bring the condensate back up to the boiling temperature
when it is recycled back to the boilers. Excessive subcooling can also result in the
formation of condensed water droplets within the last stage of the turbine, which can
damage the turbine blades. Measures to control excessive subcooling include the flow
reduction methods described above for fixed speed pumps, as well as piping
configurations that can bypass a portion of the flow around the condensers and piping
configurations that can recirculate condenser outflow back to the pump inlet. In the latter
case, some flow reduction is already occurring but pumping energy requirements are not
reduced. The control of subcooling, especially slight to moderate subcooling that might
otherwise be tolerated, provides another economic benefit for VSP retrofits through
increased plant power output.
Millstone Nuclear Plant
The Millstone Nuclear Plant on Long Island Sound in Connecticut is installing VFDs on
its circulating pumps. The goal is to reduce impingement and entrainment of winter
flounder which are present in greatest abundance in April and May (their spawning
season). The plant has agreed to reduce their 2.2 BGD flow by 40 percent during this
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§ 316(b) Existing Facilities Proposed Rule - TDD
period. Flow reduction will be required from April 4 to June 5 or until the source water
reaches 52°F (whichever happens first). To facilitate this, the facility's NPDES permit16
allows for increase in discharge AT for this period (see Exhibit 6-6 below) while retaining
the limit of 4°F increase outside mixing zone.
This example is noteworthy for several reasons: first, the facility is a nuclear plant and
second, it is a baseload facility. As discussed in the preamble, nuclear facilities may have
additional safety considerations when assessing technologies to minimize impingement
and entrainment, but VSPs appear to not trigger any concern. Second, baseload plants
are arguably the least able to reduce flow using VFD technology, as they are typically
operating continuously and have relatively constant demands for heat rejection.
However, Millstone appears to be able to capitalize on the cooler source water
temperatures in these months and balance the needs of heat rejection and impingement
and entrainment.
Exhibit 6-7 shows the revisions in permit's AT limits. Calculated reductions were
supplemented with data from PCS (the reported actual monthly max AT during Apr-May
period was in the low-mid 20s). Using a AT value of 24 compared to 41 results in a 41
percent reduction, assuming the facility is able to tailor their intake flow to operate close
to the seasonal temperature limit.
Exhibit 6-7. Flow Reduction at Millstone
Millstone Nuclear
Unit 2 Condenser
Unit 3 Condenser
Combined Discharge
Typical Seasonal Max from PCS
Normal AT Limit
DegF
32
28
32
24
Seasonal VFD AT
Limit
Deg F
46
38
41
41
Calculated
Reduction in
Intake Flow
30%
26%
22%
41%
Operational Limitations
There are technical limitations to the amount of volume reduction that can be achieved
with VSPs. For any pump, as the speed is reduced, there is a point reached where the
pump's output head is equal to the system's static head, resulting in zero flow.
Continuous operation at such a condition must be avoided because the impeller will
continue to spin and the water will recirculate within the pump casing, resulting in
damage to the pump. The flow volume response to varying speed is unique for every
combination of pump and system hydraulics, and thus the minimum safe speed must be
calculated for each application to avoid operation at or even near the shutoff head.
System controls are set such that the minimum pump speed will be well above that which
produces zero flow conditions. Two power plants in California (Pittsburg and Contra
16 See
http://www.ct.gov/dep/lib/dep/public_notice_attachments/draft_permits/071210_millstone_revised_fact_sh
eetpdf.
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Cost) have installed VSPs and documentation indicated that as much as a 50 percent
reduction in flow was attainable. However, this level of flow reduction is usually high
and typical flow reduction rates are from 8-15 percent, with some variability depending
on whether the facility is baseload or load following.
One important system characteristic that affects the performance of VSPs is whether the
total pumping head is predominantly the result of losses from friction or to static head.
Where the pumping head is predominantly from friction losses, the flow reduction
capability of VSPs is greater and overall system efficiency at reduced flows will be
greater. An example of a system where friction losses are a large component of the
pumping head would be a system that uses an inverted siphon configuration. Inverted
siphon configurations are often used in once-through systems where the condenser
elevation is close to the water surface, because they are well worth the savings in pump
energy requirements associated with the siphon configuration. Such systems require
vacuum pumps to remove the gases that collect in the high points. To prevent water
vapor from forming under the vacuum conditions that form within the siphon, the height
of the inverted siphon is limited. If the condenser elevation is above the maximum
siphon height, then the siphon height is shortened by exposing the downstream end to the
air at an elevation above that of the source water in a structure called a seal pit. Facilities
where the condensers are located well above the water surface will have higher static
components of the pumping head even when inverted siphons are used. Thus, the
condenser elevation and piping configuration will affect the performance of VSPs.
In systems where the pumping head is predominantly static head, as the pump speed is
reduced a point is soon reached where small changes in speed can result in large changes
in flow rate, especially as the pumping head approaches the system static head as
described above. Thus, the available range of flow reduction is much lower than in
systems where the pumping head is mostly friction losses. Also, in systems where the
pumping head is predominantly static head, the pump efficiency drops substantially with
reduced speed. Such systems will experience much less power usage savings. Thus, use
of VSPs in such systems is less advantageous. In these high static head systems, the
pump and system hydraulic characteristics must be carefully evaluated before deciding
whether the available benefits outweigh the costs.
When the turbine system is operating at a given generation rate (i.e., a constant steam
load), a reduction of the cooling water flow volume will result in a proportional increase
in the condenser temperatures. This will result in an increase in the difference in cooling
water temperature between the condenser inlet and the condenser outlet (AT). Many
plants have NPDES permit conditions that set a maximum limit for the AT value. This
effectively places a practical limit on the amount of flow reduction that can be achieved.
During warmer months, the increase in condenser temperature will also result in a higher
turbine exhaust pressure, resulting in a reduction in turbine efficiency. Thus, there is a
competing economic incentive to maintain higher flow levels.
Many plants have NPDES permit conditions that set a maximum effluent temperature,
which may put additional limitations on the availability of flow reduction through
variable speed pumping, especially during summer months, regardless of the economic
considerations. In fact, under extreme summer conditions, some plants may be required
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to maintain the cooling water flow at full capacity while having to reduce power output
(derate) in order to meet temperature limits.
VSPs can reduce the facility's intake flow, which is one of the most effective ways to
reduce impingement and entrainment. However, as described above, the amount of flow
reduction that can be achieved has both operational and seasonal limitations. In general,
opportunities for flow reduction are greater during cooler months and thus the benefits of
I&E reductions may be enhanced or reduced depending on the timing of the seasonal
variations in the presence and behavior of the various life stages of the affected aquatic
organisms.
Applicability
Flow reduction through the use of VSPs alone may not be sufficient to result in sufficient
I&E reductions. Because of the economic benefit associated with reduced pumping
energy requirements, VSPs may be useful even when the other technologies are fully
capable of meeting the I&E requirements alone and when the presence of sensitive
organisms coincides with the period when the source water is warmest.
The capital costs of VSP retrofit will be dependent on which components of the pumps
need to be replaced; it should be assumed, at a minimum, that a retrofit will include
replacement of the pump motors. Given the savings in pump energy costs associated
with VSPs, the net operating costs should be negative in most applications (i.e., savings
in pump energy costs will exceed any maintenance costs). Actual savings will be highly
variable depending on the system hydraulic conditions, the plant operating schedule, and
the degree of flow reduction attained. If conditions are favorable, the net operating
savings will offset capital costs (i.e., the technology will pay for itself). However, if flow
volume reduction is aggressively sought, then pump energy savings will be offset by
reduced plant output associated with a reduction in turbine efficiency.
VSPs will be most effective when:
• Facility capacity utilization rates are not very high.
• Cooling pump head is predominantly from friction losses and not static head.
• They are combined with other I&E reduction technologies.
Technologies that could benefit from being paired with VSPs may include:
• Traveling screens
• Fish barrier net
• Velocity cap
Since reduced flow volume will result in a reduction in the approach and through-screen
velocities, VSPs will likely result in improved performance of velocity caps and traveling
screens, particularly those with high approach velocities.
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Chapter 6: Technologies and Control Measures
6.4 Seasonal Flow Reductions
Seasonal flow reduction refers to the reduction or elimination of a quantity of water being
withdrawn during certain biologically important time periods. Most facilities that
practice seasonal flow reductions do so in order to reduce entrainment because
entrainment often peaks during specific times of the year (i.e., during spawning season).
Typically, this means that a facility produces less energy or no energy for some portion of
the year thereby reducing or eliminating the volume of cooling water it requires. This
may be accomplished through a variable speed drive or pump or shutting down some
portion or all of the pumping system (and unit).
See DCN 10-6702 for specific examples of spawning periods at existing facilities. In
these examples, there are often organisms that have some degree of spawning at all times
of the year but peak spawning periods can be identified. If only species of concern are
examined, the spawning period analysis may appear very different than a broader
analysis of all species present.
Additionally, the specific timing and abundance of organisms present may affect how
seasonal flow reductions are achieved. As an example, Exhibit 6-8 below presents two
possible scenarios that might be addressed differently under a seasonal flow reduction
approach.
Exhibit 6-8. Examples of Seasonal Flow Reductions
-Speciesl
-5pecies2
Total Entrainables
Unique Peaks
-Speciesl
•SpecieE2
Total Entrainables
Because of the difficulty in projecting, on a national scale, which facilities might employ
seasonal flow reductions (due to the species present, seasonal utilization rates, percentage
of flow reduced and other factors), EPA did not include seasonal flow reductions in any
formal analysis of compliance costs.
6.5 Water Reuse
EPA encourages any reduction in water withdrawals or water usage in general.
Throughout the 316(b) rulemaking process, EPA has included provisions for water reuse
whereby a facility that uses water withdrawn for another purpose (e.g., contact cooling or
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process water) as cooling water, then said volume would not be considered in
determining whether a facility is subject to the regulation.1?
For power plants, water reuse is typically not an available option, as there is very little
water that is used for purposes other than non-contact cooling; the "credit" would be
extremely small.
Manufacturers, on the other hand, may realize substantial benefits from water reuse. As
discussed above, a facility may avoid national 316(b) requirements if it reuses a
significant portion of its cooling water and does not meet the 25 percent threshold.
Additionally, the proposed rule provides that entrainment requirements at new units at an
existing facility do not apply to cooling water that is reused for another purpose. See the
preamble for the proposed rule for more information on how EPA considered water reuse
in the regulatory framework.18
6.6 Alternate Cooling Water Sources
Cooling water need not be withdrawn from a surface waterbody. Groundwater, grey
water (i.e., POTW effluent) or other sources of water may be used for once-through
cooling or as make-up water for a closed-cycle system. Unfortunately, many facilities
have cooling needs that substantially outpace the volume of water available to them from
alternate sources, especially for once-through cooling systems. In the California's
Coastal Power Plants: Alternate Cooling System Analysis, OPC analyzed alternate
sources as cooling tower makeup water but concluded that even for power plants located
in densely populated areas of southern California (where infrastructure to facilitate
alternate sources such as grey water), alternate sources of cooling water were not a viable
option. Similarly, EPA did not consider any regulatory analyses or alternatives that
relied on alternative cooling water sources.
6.7 Screening Technologies
Screening technologies have been used on cooling water intake structures for more than
75 years to prevent debris and aquatic organisms from entering the condensers. These
technologies include both traveling screens and passive screens. Over 93 percent of
power plants and 73 percent of manufacturers use some sort of screening technology (see
Chapter 4 of this TDD).
Exhibit 6-9 provides a generic diagram of a cooling water intake structure that employs
traveling screens, with the power plant operations and cooling water discharge also
shown.
17 See, e.g., 40 CFR 125.83 (definition of cooling water).
18 Also see Chapter 8 of the TDD for information on how EPA considered the relationship between non-
contact cooling water, contact cooling water, and process water flows in developing compliance costs.
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Chapter 6: Technologies and Control Measures
Exhibit 6-9. Generic CWIS With Traveling Screens
Fixed Bar Racks
Traveling screens (see Exhibits 6-10 and 6-11) are used at most cooling water intake
structures. These screens were originally designed for debris control, but also serve to
prevent some fish and shellfish from entering the cooling system. Traveling screens have
been installed in numerous environmental conditions: salt water, brackish water, fresh
water, and icy water. There are many types of traveling screens (e.g., through-flow, dual-
flow, center-flow). The most common design in the US is the through-flow system. The
screens are typically installed behind bar racks (trash racks) but in front of the water
circulation pumps. The screens rotate up and out of the water where debris (including
impinged organisms) is removed from the screen surface by a high pressure spray wash.
Screenwash cycles are triggered manually, on a timer, or by a certain level of head loss
across the screen (indicating clogging). By design, this technology works by collecting
or "impinging" fish and shellfish on the screen.
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Exhibit 6-10. Traveling screen at Eddystone Generating Station, Eddystone, PA
Exhibit 6-11. Traveling screen diagram
LOW PRESSURE
FISH WASHING
SYSTEM
NEOPRENE-
DEFUECTOR
FISH
SLUICE
TROUGH
CONVENTIOKAL
HIGH PRESSURE
SPRAY
SIDE ELEVATION
(5-20
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 6: Technologies and Control Measures
Passive screens are non-moving fixed screens that use physical exclusion to minimize
debris and fish from entering the condensers and hydrodynamics to prevent the buildup
of debris and screen loading leading to head loss. Passive screens include wedgewire
screens, perforated pipes, and porous dikes/leaky dam systems. Wedgewire screens are
the most common type of passive screen and the most effective passive screen at
minimizing impingement and entrainment (see Exhibit 6-12). Wedgewire screens are
discussed in more detail later in this chapter.
Exhibit 6-12. Cylindrical wedgewire screen
Traveling screens and passive screens are further defined by screen mesh size as coarse
mesh or fine mesh. Coarse mesh screens have mesh sizes of 3/8" (about 9.5 mm) and
fine mesh screens have mesh sizes typically ranging from about 0.5 mm to 3 mm
depending on the organisms to be protected. Coarse mesh screens are generally not
protective of smaller organisms (such as eggs and larvae) that may become entrained by
passing through the screen openings and into the cooling system. Coarse mesh systems
may also cause mortality of impinged fish due to impact, stress, descaling, and
suffocation against the screen. Fine mesh screens may prevent entrainment, but may also
lead to increased mortality of impinged organisms (specifically eggs and larvae that
would otherwise have been entrained).
The sections below discuss each screen type in greater detail.
6.8 Conventional Traveling Screens
Conventional traveling screens, also called coarse mesh traveling screens, are a common
component of virtually all cooling water intake structures and provide essential debris
and fouling control for pumps and condensers; over 83 percent of all existing facilities
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already employ this type of screen.19 The screens are mounted on fixed-loop chains or
belts that rotate through the water column and remove debris from the intake stream,
preventing the entrainment of debris through the intake system where they can damage
sensitive pumps and condensers. Objects collected on the screen are typically removed
with a high-pressure spray (> 60 pounds per square inch [psi]) and deposited in a
dumpster or debris return trough for disposal. Screens are rotated and washed
periodically based on a set time interval or when the pressure differential between the
upstream and downstream faces exceeds a set value. Intermittent rotation minimizes
operational wear and tear and keeps maintenance costs relatively low. In the U.S.,
facilities employ multiple traveling screen types, including dual-, center-, and through-
flow designs. The through-flow type—the most common at U.S. facilities—removes
debris and screenings from the water on the upstream (ascending) side. Dual and center-
flow designs screen water through the ascending and descending screen faces, which
prevents debris carryover to the downstream side.
Conventional traveling screens were not designed with the intention of protecting fish
and aquatic organisms that become entrapped against them. Marine life may become
impinged against the screens from high intake velocities that prevent their escape.
Insufficiently strong species or life stages may suffocate after prolonged contact with the
screens. Exposure to high pressure sprays and other screening debris may cause
significant injuries that result in latent mortality, or increase the susceptibility to
predation or reimpingement. Organisms that do survive initial impingement and removal
are not typically provided with a specifically-designed mechanism to return them to the
water body and are handled in the same fashion as other screening debris. These screens
do not address organism entrainment, as eggs and larvae are typically swept through the
screen and into the condensers.
6.8.1 Technology Performance
Conventional screens are not used to mitigate the impacts of impingement and/or
entrainment.
6.8.2 Facility Examples
Conventional screens are used at a large number of existing facilities.
6.9 Modified Coarse Mesh Traveling Screens
Following the 1972 Clean Water Act's requirement to use technology-based solutions to
minimize adverse environmental impacts, some conventional coarse mesh traveling
screen systems were modified to reduce impingement mortality by removing fish trapped
19 The percentage is based on responses to the industry questionnaire. Upon further review of facilities that
did not identify a traveling screen, EPA found that most of these facilities did in fact have traveling screens.
As a result, EPA assumes that virtually all existing facilities have a traveling screen at some point in their
cooling water intake system. The screen may be located in the forebay instead of at the cooling water
intake structure, but some form of screening is almost always necessary.
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against the screen and returning them to the receiving water with as few injuries as
possible. The modified screens, also known as "Ristroph" screens, feature capture and
release modifications that include a fish collection bucket or trough, a low pressure spray,
and a fish return system. In the simplest sense, these screens are fitted with troughs (also
referred to as buckets) containing water that catch the organisms as they are sprayed off
of the screen. The return component consists of a gentle mechanism to remove impinged
fish from the collection buckets, such as a low-pressure spray. The buckets empty into a
collection trough that returns fish to a suitable area in the source waterbody. These
modified "Ristroph" screens have shown significant improvements in reducing
impingement mortality compared with unmodified screen systems. Of the 766 existing
facility intakes that were reported in the detailed questionnaires, 9 intakes specifically
reported "Ristroph" traveling screens, 16 additional intakes may qualify as having
"Ristroph-type" traveling screens, 50 intakes reported having "Fish Buckets, Baskets, or
Trays," and 130 intakes reported an inlet or through-screen screen velocity of < 0.5 fps.
The first Ristroph screens, named for the lead engineer who developed the initial
prototype, were installed at Dominion Power's Surry Station in Virginia in 1977. The
existing screen panels were fitted with water-retaining collection buckets at the base of
each panel that lifted impinged fish out of the main stream flow as the screens rotated. At
the top of the screen assembly, buckets emptied into a collection trough that returned fish
to a suitable area in the source water body. The initial survival rate for the modified
screen at Surry Station, averaged across all species, was 93.3 percent (EPRI1999). Bay
anchovy had the lowest initial survival at 83 percent (White and Brehmer 1977, Pagano
and Smith 1977). Notably, these survival rates did not account for latent mortality that
may have resulted from injuries sustained during the collection and removal process.
Data from early applications of the "Ristroph" screen design showed that while initial
survival rates might be high at some installations, latent mortality rates were higher than
anticipated, indicating significant injuries could be sustained during the impingement and
return process that were not immediately fatal. Many of these flaws were identified in an
analysis of a modified screen design proposed for the Indian Point facility in New York
by Fletcher (1990; see DCN 5-4387). This analysis identified points in the
collection/removal process where latent injuries might be sustained, including poor debris
removal, which became entangled with impinged fish and prevented their safe return;
rough or corroded screen basket materials that increased descaling; and fish
reimpingement occurring when fish escaped the ascending buckets by jumping over the
outer bucket lip just prior to the bucket breaking the surface.
Most significantly, Fletcher identified a principal cause for many of the injuries sustained
by impinged fish. Screen panels retrofitted with water-retaining buckets induced a
secondary flow pattern in the bucket while it remained below the water line, creating
turbulent conditions in the bucket that repeatedly buffeted any fish against the screen and
bucket materials. Fletcher observed that fish caught in this flow pattern suffered far more
significant injuries than those which only came in contact with the screen mesh.
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Several critical modifications were proposed following this analysis, many of which have
been adopted by other facilities, including:
• Redesign of collection buckets to address hydraulic buffeting with a new shape
and inclusion of a flow spoiler on the outer bucket edge. These modifications
minimize turbulence within the bucket and prevent significant injuries during
capture and retention.
• Addition of a fish guard rail/barrier to prevent fish from escaping the collection
bucket and increasing their total impingement time. The fish guard rails extend
above the water surface before the main bucket as the screens are rotated.
• Reordered fish and debris removal. At Indian Point, filamentous debris collecting
on the screen panels was originally removed after impinged fish. This debris
blocked the screen panels, however, and prevented the fish removal spray system
from functioning properly. The modified design included a high pressure spray to
remove debris on the ascending side prior to removing impinged fish.
• Replaced screen panel materials with smooth woven mesh. Significant descaling
was observed with more abrasive screen designs such as crimped or welded wire.
A schematic comparison of each basket design type is shown in Exhibit 6-13.
Exhibit 6-13. Ristroph and Fletcher Basket Designs
\ \
\ Screen ,., ^ ,. ^ \ Screen
\ Panel * Water Line + ^ pane,
\ \ i
Auxiliary/^ \
Screen
J9 \
\_y
Fish Flow \_X Fish
Bucket Spoller Bucket
Original Ristroph Design Fletcher Modifications
The Fletcher study also evaluated impingement durations up to 30 minutes. Impingement
durations of 10 minutes or less did not significantly affect survival, with mortality rates
increasing with longer impingement times. Likewise, sufficient water retention in the
buckets was shown to be essential. Exposure to the air and temperature extremes, even
for a short duration, could negatively impact fish survival. These findings support the
general assumption that modified Ristroph screens must be continually rotated instead of
the periodic rotation schedule common with conventional screen systems.
6.9.1 Screen Design Elements
The collection portion of a modified Ristroph system comprises all CWIS elements
geared towards fish protection up to the point where fish are removed from the
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screens/buckets. The collection system's key function is to capture entrapped fish that
cannot escape the intake screens and remove them from the intake flow for safe return to
the source water body. This must be accomplished by sustaining all captured fish with
sufficient water and minimizing potential injuries from screen interactions and
turbulence. While the cooling water intake structure location and orientation may play a
significant role in determining how many fish and shellfish are susceptible to
impingement before coming in contact with the screens, this subsection focuses on the
screens and fish return systems. EPA notes that a comprehensive design approach that
carefully considers the cooling water intake location and orientation prior to installing a
modified traveling screen system may yield significant benefits. At existing facilities,
however, many of these modifications are more problematic due to space constraints and
interference with existing systems, and may not be practical options given their cost and
complexity.
Screen Type/Design
The screen itself is the first point at which any fish will come in contact with a physical
element. When a conventional traveling screen is modified to include Ristroph and
Fletcher modifications, many of the system's existing elements may need to be upgraded
to incorporate newer, more fish-friendly materials, or with more robust mechanical
components that are better suited to the new operating conditions. New components like
fish buckets or rails also require careful consideration to maximize the desired level of
protection. All of these factors must be evaluated against the specific demands at a
particular site such as water quality, intake velocity, and species composition and
abundance. In some cases, it may be more economical, and ultimately more efficient, to
replace the entire screen assembly rather than retrofit existing components. A
comprehensive retrofit may mitigate other effects and better enable all components to
90
work more efficiently with one another.
Screen Mesh Material
The primary design focus for existing conventional traveling screen systems is the
removal of smaller debris (i.e., debris not screened by a trash rack) that may clog or
damage sensitive intake equipment like pumps and condensers. The screen panel
material is selected to serve this function while remaining durable and functional with the
lowest possible maintenance costs. Screen materials must be able to resist corrosion and
degradation while being alternately immersed in water and exposed to air. They must
also withstand potentially high debris loads that might compromise weaker materials and
damage the intake system. Stainless steel is among the most common screen material
used for traveling screen, although copper alloys are also used where screen fouling from
colonial organisms is a concern. Likewise, advances in engineered polymer coatings
have proven effective in resisting corrosion and degradation.
20 EPA's cost methodology for the proposed Existing Facilities rule included full replacement costs for all
screen components.
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For a modified traveling screen system, materials and configurations that are smooth by
design and can maintain a near-design condition will assist in minimizing any contact
injuries sustained by impinged fish. Smoother configurations and materials, such as
woven wire mesh (as opposed to punched or welded mesh) and SmoothTex flat wire, will
also aid fish removal and limit descaling during transfer to the return system.
Through-screen Area and Mesh Size
As noted above, many existing conventional screening systems were initially designed to
remove debris from the intake stream to prevent damage to other equipment. The
optimal mesh size prevents entrainment of any debris large enough to clog the condenser
tubes while maximizing the through-screen area, and allows the facility to optimize its
intake velocity-to-screen area ratio and install a properly sized system. Because many
condenser tubes used in power plants are 3/4 or 7/8 inches in diameter, a 3/8-inch mesh
size (i.e., coarse mesh) is found at a majority of facilities employing traveling screens.
Screen intake velocity may be categorized into two types: approach and through-screen.
The approach velocity is generally defined as the localized velocity component
perpendicular to the screen face measured at a distance from the screen (often three
inches). Through-screen velocity, as the term implies, is the velocity of water passing
through the screen mesh openings. This is difficult to measure in the field, but a
reasonable through-screen estimate can be calculated by dividing the intake structure's
flow rate by the total open area submerged in the water column. Changes to either the
water depth (tidal cycles or seasonal flooding) or screen open area (from fouling or
clogging) affects both velocity values if the same intake flow is maintained. Likewise,
sedimentation in front of the screens or intake structure constricts the flow channel and
increases the approach velocity.
The mesh opening and the total screen size are key factors in determining the CWIS's
intake velocity, which, in turn, influences the impingement mortality rate. This
relationship is well-established, with higher intake velocities generally corresponding to
increased impingement rates and higher mortalities due to injury. Several different swim
speed studies have shown that velocities at or below 0.5 feet per second (fps) would be
expected to cause de minimis impingement. For the Phase I rule, EPA compiled data
from three studies on fish swim speeds and found that a velocity of 0.5 fps would protect
91
96 percent offish tested. Maintaining an intake velocity as low as possible is critical to
reducing overall impingement probability. For some species, a velocity less than 0.5 fps
is necessary, e.g., the State of Alaska requires a velocity limit of 0.1 fps to protect
salmonids.22 EPA has long recognized the benefits of maintaining a low through-screen
velocity (of 0.5 fps or less) by including it as an impingement mortality compliance
option in the previous 316(b) rulemakings.
Retrofitting existing traveling screens to operate with a fish collection system may
decrease the total through-screen area by blocking a portion of the screen face with fish
bucket or rail. Any impact on intake velocities, however, will depend on the original
21 66 FR 65274
22 See DCN 1-5015-PR in the Phase I docket.
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screen design and the modifications made to incorporate new equipment. Advances in
screen design, materials, and fabrication methods enable newer screen systems that have
been designed with the fish protection measures to achieve comparable, and sometimes
greater, through-screen areas than older equipment that is retrofitted. In some cases, it
may be more advantageous to replace the entire screen assembly rather than retrofit the
existing traveling screen (Gathright 2008).
Collection Buckets
One of the more critical elements, collection buckets incorporate several design elements
to maximize safe capture of impinged fish. Buckets should extend across the screen
panel's full length to prevent gaps where fish may fall through and be deep enough to
hold sufficient water for the expected number and size of species impinged. Depending
on screen's size and rotation interval, captured fish may held in these buckets for several
minutes, often with other fish. Close proximity with other fish in a confined space,
particularly with those of another species, may create stress and behaviors that result in
additional injury. The selected bucket size and depth should reflect the target species and
allow for sufficient space and water coverage to sustain them during transfer to the return
system.
The design of pre-Fletcher collection buckets were found to cause significant turbulence
within the buckets, leading to high mortality rates as fish were buffeted against the screen
elements. The modifications described by Fletcher to minimize flow-induced turbulence
in the collection bucket have become common practice for this system type. The
bucket's shape was redesigned to include an additional lip or flow spoiler attached to the
bucket's leading edge. Further, modifications to prevent fish from escaping the rising
bucket as it nears the surface may also be necessary. A rail or guard that extends above
the water surface before the rest of the bucket keeps capture fish in the bucket and
prevents their re-impingement (Exhibit 6-12).
6.9.2 Removal and Return System Design Elements
The removal and return portion of the modified system comprises all elements that aid in
the removal offish from the screens and buckets and returns them to a safe location in the
source water body.
Debris and Fish Removal
Traveling screen systems without specific measures to reduce impacts to aquatic
organisms will collect impinged fish and debris without making a distinction between the
two. One of the major advances associated with the Ristroph design is the inclusion of a
separate fish removal system and return trough that sought to segregate aquatic species
from other debris. Unavoidably, some debris will end up with fish return trough and,
vice versa; the key is designing the system to separate the two as much as possible.
Separate spray removal systems—a low pressure spray for removing fish and a high
pressure spray for debris—are typically included as part of a two-stage removal process
that sorts most fish and debris to their own dedicated troughs.
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Using a low pressure spray (less than 20 pounds per square inch) is based on the
assumption that fish will not become attached or entangled with the screen panels and
thus require only a "gentle removal" from the screens and buckets. Removal in this
manner is also aided by smooth materials and structural components that eliminate
protrusions, sharp angles and rough surfaces that prevent fish release. Depending on the
spray head's position relative to the screen panel, it may be advantageous to remove
debris before fish. Heavy debris loads might clog screen panels and block the low-
pressure spray from functioning properly if the spray head is located behind the screen, as
described in the Indian Point analysis (Fletcher 1990). In this instance, a high pressure
spray (60 to 80 psi) placed ahead of the low pressure spray forcibly removes debris that
has become attached to the screen panels and may increase fish removal efficiency.
When low pressure spray heads are placed lateral to the screen instead of behind, it may
be more effective to remove debris after any impinged fish. As noted above, deciding the
order of low and high pressure spray must be carefully considered to optimize fish
protection.
Fish Return
Mortality-inducing injuries are more likely to occur during the collection and removal
portion of a modified traveling screen system. The return system, however, plays an
important role in the overall effectiveness and has many critical design elements that
must be considered to ensure safe return of healthy fish. Most criteria are universally
applicable to any modified traveling screen system, and include:
• Construction materials. Structural components should be constructed using
materials that minimize rough surfaces and protrusions that may cause abrasions,
contusions, descaling, or more serious physical injury during the return process.
Fiberglass-reinforced plastic, PVC, and stainless steel share this characteristic
while also being resistant to biofouling. Joints between pipe sections should also
be as smooth as possible.
• Size and capacity. As with the collection buckets themselves, the return trough
should be able to accommodate the largest species in the maximum estimated
number without overcrowding.
• Transport velocity. The water velocity in the return trough must be strong enough
to overcome the swimming capacity of the strongest species and ensure their
return to the water. A gravity return system will require a sufficient slope and
water volume to induce the necessary flushing action. Pump-aided returns can
adjust the return pressure accordingly.
• Flow disruptions. Where possible, the return should avoid sharp angles and short
bend radius turns to reduce flow disruption and redirection. At all points, care
should be taken to ensure a smooth, consistent return flow free from hydraulic
jumps and flow separation areas.
• Exposure. Fish confined in a return trough have limited avenues of escape and,
depending on the length of the return, may have long transit times back to the
source water body. Because an open trough may unnecessarily expose these fish
to predation from birds or other animals, the preference in most cases is to enclose
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the system entirely until fish are returned to the water. This has the added benefit
of reducing exposure to air temperature extremes. In cold weather climates, even
brief exposure to sub-freezing temperatures can increase mortality.
• Flushing cycle. Adequate flow must be maintained in the trough to clear all
transported fish from the return trough and drain completely following the cycle's
completion to prevent backflow and biofouling/deoxygenation. A consistent flow
may also be maintained in lieu of draining the trough.23
• Return Location. The final return point in the water body must be located outside
of the intake's radius of influence to prevent reimpingement. The final transition
to the water body should be smooth and free of any significant hydraulic jump.
Water quality and temperature should be comparable to conditions at the intake to
prevent any contact shock upon return. Preferably, organism re returned to the
water quickly (i.e., to a nearby location) as longer exposure to the return system
may cause descaling or other injuries. An ideal location will also avoid areas
where predators congregate or attract increased predation.
6.9.3 Operation and Maintenance
Routine maintenance and operating protocols enacted for each modified traveling screen
installation also play a key role in determining the system's overall effectiveness. While
some parameters are widely applicable (e.g., rotation interval) others are tailored to meet
the specific needs at a particular location and may vary significantly from one facility to
another. These parameters include:
• Rotation interval. Evaluations at many different facilities over the last 30 years
have generally shown that impingement mortality rates are lowest when traveling
screens are rotated continuously at a fixed speed instead of the intermittent
rotation schedule more common with conventional traveling screens. Continuous
rotation ensures that any impinged fish will be caught on the screens for a
minimum time period, but in some cases may not be necessary, at least for all
seasons. Periodic full rotation cycles may be sufficient (i.e., some number of
complete rotations per hour) when impingement is dramatically lower or non-
existent during certain times of the year (e.g., seasonal migrations may limit the
critical time period to a few weeks or months of the year). Additionally, new
designs use composite materials to frame the traveling screens which weigh less
and reduce wear on chains and drives.
• Rotation speed. The longer a fish is impinged against a screen, the higher its
probability for suffering significant injury. Continuously rotated screens should
travel fast enough to minimize the impingement durations but be slow enough to
prevent higher maintenance costs associated with a faster screen rotation. The
23 Facilities usually withdraw screenwash water from within the intake structure (i.e., after it has passed
through the intake screens) or from a separate pump in the area of the intake structure. In either case, EPA
envisions that any increase in flow to accommodate improved flushing of the return system would be small
compared to the cooling water flow but nonetheless should generally not be included in calculating a
facility's cooling water withdrawals (for calculating DIP or the percent of water withdrawn for cooling
purposes).
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rotation speed should also minimize the amount of time the fish are out of the
water.
• Preventative maintenance. Modified screens that are rotated continuously will
incur higher operating and maintenance costs than a conventional traveling screen
cycled intermittently. Mechanical equipment may require more robust
components to accommodate the increased rotation frequency and higher rotation
speeds necessary to minimize the impingement duration. Likewise, the screen
panels may require more intensive maintenance that minimizes corrosion and
biofouling, which may increase mortality rates by creating a rougher or more
unforgiving contact surface.
Retrofit/Downtime issues
Modified traveling screens with fish handling systems are among the oldest technologies
developed specifically to address impingement and these screens have been widely
deployed and studied throughout the United States. Because so many existing facilities
already use conventional traveling screens, modified traveling screens are broadly
applicable and may not require significant changes to the CWIS to achieve high levels of
performance. A successful installation is generally independent of factors such as
waterbody type, climate zone, age, fuel type or intake flow. In other words, a facility that
has previously used a conventional traveling screen (nearly all facilities, operating under
a wide variety of conditions) should also be able to employ a modified traveling screen.
Compared with other impingement design and construction technologies used as retrofit
options, modified traveling screens are relatively easy to install and operate. Changes to
the screens themselves are relatively straightforward and, in all but the most unique
instances, do not require substantial modification or expansion of the screen houses and
can be completed during normal maintenance outages without affecting the facility's
generating schedule. Likewise, because this technology does not alter the cooling water
Row per se, the facility's generating output is unaffected; no energy penalty is incurred
save for the small increase in electrical usage due to continual or more frequent screen
rotation.
6.9.4 Technology Performance
Conventional traveling screens that have been modified to include a fish collection and
return system based on Ristroph and Fletcher designs have an extensive record of
performance at numerous facilities. Data shows impingement survival values greater
than 90 percent for many species. However, the actual performance of conventional
traveling screens is typically less than 90 percent when holding times are considered; in
most cases, the longer an organism is held, the less likely it is to survive. Additionally,
larval impingement on fine mesh screens must also be addressed when reviewing
technology performance. See Chapter 11 of the TDD and the preamble to the proposed
rule for more information about how EPA assessed these data.
EPA also found that in many cases, only a few species comprise over 90 percent of the
impinged organisms. For example, at the Arthur Kill Station, Atlantic herring, blueback
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herring and bay anchovy composed over 90 percent of the impinged species during the
course of the study as described below. In addition, some of the impinged species may
not be typically considered "species of concern," i.e., highly valued commercial or
recreational species or listed species. Gizzard shad and bay anchovy are commonly
impinged organisms reflected in study data, but may not be considered as species of
concern.
6.9.5 Facility Examples
Salem Generating Station
Salem Generating Station, on the Delaware Bay estuary in New Jersey, converted 6 of its
12 conventional traveling screen assemblies to a modified design that incorporated
improved fish buckets constructed of a lighter composite material (which improved
screen rotation efficiency), smooth-woven mesh material, an improved spray wash
system (both low and high pressure), and flap seals to improve the delivery of impinged
fish from the fish buckets to the fish return trough (EPRI2007). The initial study period
consisted of 19 separate collection events during mid-summer 1996. The configuration
of the facility at the time of the study (half of the screens had been modified) allowed for
a direct comparison of the effectiveness of the modified and unmodified screens on
impingement mortality rates. The limited sampling timeframe enabled the analysis of
only the species present in numbers sufficient to support any statistical conclusions.
1,082 juvenile weakfish were collected from the unmodified screens while 1,559 were
collected from the modified structure. Analysts held each sample group separately for 48
hours to assess overall mortality due to impingement on the screens. Results showed that
use of the modified screens had increased overall survival by as much as 20 percent over
the use of the unmodified screens. Approximately 58 percent of the weakfish impinged
on the unmodified screens survived, whereas the new screens had a survival rate
approaching 80 percent. Both rates were based on 48-hour survival and not adjusted for
the mortality of control samples.
Water temperature and fish length are two independent factors cited in the study as
affecting overall survival. Researchers noted that survival rates decreased somewhat as
the water temperature increased, possibly as a result of lower levels of dissolved oxygen.
Survival rates decreased to a low of 56 percent for the modified screens when the water
temperature reached its maximum of 80°F. At the same temperature, the survival rate on
the unmodified screens were 35 percent. Differences in survival rates were also
attributable to the size of the fish impinged. In general, small fish (< 50 mm) fared better
on both the modified and unmodified screens than large fish (> 50 mm). The survival
rates of the two size categories did not differ significantly for the modified screens
(85 percent survival for small, 82 percent for large), although a more pronounced
difference was evident on the unmodified screens (74 percent survival for small, 58
percent for large).
Salem Generating Station conducted a second series of impingement sampling from 1997
to 1998. By that time, all screen assemblies had been modified to include Ristroph/post-
Fletcher fish buckets and a fish return system. Additional modifications to the system
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sought to enhance the chances of survival offish impinged against the screens. One
modification altered the fish return slide to reduce the stress on fish being delivered to the
collection pool. Flap seals were improved to better seal gaps between the fish return and
debris trough, thus preventing debris from affecting returning fish. Researchers used a
smaller mesh screen in the collection pools during the 1997-1998 sampling events than
had been used during the 1995 studies. The study notes that the larger mesh used in 1995
might have enabled smaller fish to escape the collection pool. Since smaller fish
typically have a higher mortality rate due to physical stress than larger fish, the actual
mortality rates may have been greater than those found in the 1995 study. The second
impingement survival study analyzed samples collected from October through December
1997 and April through September 1998. Samples were collected twice per week and
analyzed for survival at 24- and 48-hour intervals. Six principal species were identified
as constituting the majority of the impinged fish during the sampling periods: weakfish,
white perch, bay anchovy, Atlantic croaker, spot, andAlosa spp. Fish were sorted by
species and size, classified by their condition, and placed in holding tanks. For most
species, survival rates varied noticeably depending on the season. For white perch,
survival was above 90 percent throughout the sample period (as high as 98 percent in
December). Survival rates for weakfish varied from a low of 18 percent in July to a high
of 88 percent in September. Although the number of weakfish collected in September
was approximately one-fifth of the number collected in July, a possible explanation for
the variation in survival rates is the modifications to the collection system described
above, which were implemented during the study period. Similarly, bay anchovy fared
worst during the warmer months, dropping to a 20 percent survival rate in July while
achieving a 72 percent rate during November. Rates for Atlantic croaker varied from 58
percent in April to 98 percent in November. Spot were collected in only one month
(November) and had a survival rate of 93 percent. The survival rate for the Alosa spp.
(alewife, blueback herring, and American shad) remained relatively consistent, ranging
from 82 percent in April to 78 percent in November. For all species in the study, with the
exception of weakfish, survival rates improved markedly with the use of the modified
screen system when compared to data from 1978-1982, when the unmodified system was
still in use.
EPA conducted a site visit to Salem in January 2008. See DCN 10-6513.
Arthur Kill Station
The Arthur Kill Station is located on the Arthur Kill estuary in New York. To fulfill the
terms of a consent order, Consolidated Edison modified two of the station's dual-flow
intake screens to include smooth mesh panels, fish-retention buckets, flap seals to prevent
fish from falling between screen panels, a low-pressure spray wash system (10 psi), and a
separate fish return sluiceway (EPRI2007). One of the modified screens had mesh of
1/8-inch by 1/2-inch while the other had 1/4-inch by 1/2-inch while the six unmodified
screens all had 1/8-inch by 1/8-inch mesh. Screens were continuously rotated at 20
ft/min during the sampling events. The sampling period lasted from September 1991 to
September 1992. Weekly samples were collected simultaneously from all screens, with
the exception of 2 weeks when the facility was shut down. Each screen sample was held
separately in a collection tank where initial mortality was observed. A 24-hour survival
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rate was calculated based on the percentage offish alive after 24 hours versus the total
number collected. Because a control study was not performed, final survival rates have
not been adjusted for any water quality or collection factors. The study did not evaluate
latent survival beyond the 24-hour period. Atlantic herring, blueback herring and bay
anchovy typically composed the majority (> 90 percent) of impinged species during the
course of the study period. Bay anchovy alone accounted for more than 72 percent of the
sample population. Overall performance numbers for the modified screens are greatly
influenced by the survival rates for these three species. In general, the unmodified
screens demonstrated a substantially lower impingement survival rate when compared to
the modified screens. The average 24-hour survival for fish impinged on the unmodified
screens was 15 percent. Fish impinged on the larger mesh (1/4") and smaller mesh (1/8")
modified screens had survival average 24-hour survival rates of 92 percent and 79
percent, respectively.24 Most species with low survival rates on the unmodified screens
showed a marked improvement on the modified screens. Bay anchovy showed a 24-hour
survival rate increase from 1 percent on the unmodified screens to 50 percent on the
modified screens. The study period at the Arthur Kill station offered a unique
opportunity to conduct a side-by-side evaluation of modified and unmodified intake
structures. The results for 24-hour post-impingement survival clearly show a marked
improvement for all species that had fared poorly on the conventional screens. The study
notes that lower survival rates for fragile species such as Atlantic herring might have
been adversely affected by the collection tanks and protocols. Larger holding tanks
appeared to improve the survival of these species, suggesting that the reported survival
rates may under-represent the rate that would be achieved under normal (unobserved)
conditions, though by how much is unclear.
Dunkirk Steam Station
Dunkirk Steam Station is located on the southern shore of Lake Erie in New York. In
1998 a modified dual-flow traveling screen system was installed on Unit 1 for an
impingement mortality reduction study (EPRI 2007). The new system incorporated an
improved fish bucket design to minimize turbulence caused by flow through the screen
face, as well as a nose cone on the upstream wall of the screen assembly. The nose cone
was installed to reduce the flow and velocity variations that had been observed across the
screen face. Samples were collected during the winter months of 1998/1999 and
evaluated for 24-hour survival. Four species (emerald shiner, juvenile gizzard shad,
rainbow smelt, and spottail shiner) compose nearly 95 percent of the sample population
during this period. All species exhibited high 24-hour survival rates; rainbow smelt fared
worst at 83 percent. The other three species had survival rates of better than 94 percent.
Other species were collected during the sampling period but were not present in numbers
significant enough to warrant a statistical analysis. The results presented above represent
one season of impingement sampling. Species not in abundance during cooler months
might be affected differently by the intake structure. Sampling continued beyond the
winter months, but data has not yet been reviewed by EPA.
24 Note that these values may not directly compare with the impingement mortality performance
requirements, which are based on the use of 3/8 inch mesh.
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Huntley Steam Station
Huntley Steam Station is located on the Niagara River in New York. The facility
replaced four older conventional traveling screens with modified Ristroph screens on
Units 67 and 68 (EPRI2007). The modified screens are fitted with smoothly woven
coarse mesh panels on a rotating belt. A fish collection basket is attached to the screen
face of each screen panel. Bucket contents are removed by low-pressure spray nozzles
into a fish return trough. High-pressure sprays remove remaining fish and debris into a
separate debris trough. The study does not contain the rotation interval of the screen or
the screen speed at the time of the study. Samples were collected over five nights in
January 1999 from the modified-screen fish return troughs. All collected fish were sorted
according to initial mortality. Four targeted species (rainbow smelt, emerald shiner,
gizzard shad, and alewife) were sorted according to species and size and held to evaluate
24-hour survival rates. Together, the target species accounted for less than 50 percent of
all fish impinged on the screens. (An additional 6,364 fish were not held for latent
survival evaluation.) Of the target species, rainbow smelt and emerald shiners composed
the greatest percentage with 57 and 37 percent, respectively. Overall, the 24-hour
survival rate for rainbow smelt was 84 percent; some variation was evident for juveniles
(74 percent) and adults (94 percent). Emerald shiner were present in the same general
life stage and had a 24-hour survival rate of 98 percent. Gizzard shad, both juvenile and
adult, fared poorly, with an overall survival of 5 percent for juveniles and 0 percent for
adults. Alewife were not present in large numbers (n = 30) and had an overall survival
rate of 0 percent. The study notes the low survival rates for alewife and gizzard shad and
posits the low water temperature as the principal factor. At the Huntley facility, both
species are near the northern extreme of their natural ranges and are more susceptible to
stresses associated with extremes in water conditions. The water temperatures at the time
of collection were among the coldest of the year. Laboratory evaluations conducted on
these species at the same temperatures showed high degrees of impairment that would
likely adversely affect post-impingement survival. A control evaluation was performed
to determine whether mortality rates from the screens would need to be adjusted for
waterbody or collection and handling factors. No discrepancies were observed, and
therefore no corrections were made to the final results. Also of note in the study is the
inclusion of a spray wash collection efficiency evaluation. The spray wash and fish
return system were evaluated to determine the proportion of impinged fish that were
removed from the buckets and deposited in the fish trough instead of the debris trough.
All species had suitable removal efficiencies.
6.10 Geiger screens
Geiger screens are a relatively new type of traveling screen made up of a series of curved
screen panels that rotate along the face of the intake screen along an oval path, much like
a luggage carousel at an airport (see Exhibit 6-14). This configuration serves to virtually
eliminate debris carryover. Geiger screens may be coarse mesh or fine mesh. The
standard design is to use stainless steel for the construction, using different grades for
freshwater and saltwater. As a result, capital costs for multi-disc screens may be higher
for freshwater systems than conventional screens but comparable for saltwater systems.
Standard screens have two drive chains and difficulty in maintaining equal tensioning on
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Chapter 6: Technologies and Control Measures
both often results in sprocket failure. O&M costs should be lower for multi-disc screens,
as they only have one drive chain. Elimination of debris carryover can save on condenser
cleaning O&M. In addition, because water passes through the screens only once, head
loss across the screen is lower as compared to other types of screens.
The sickle-shaped screen panels can be fitted with different types of screen materials
such as drilled plastic, nylon or metal screen mesh. One manufacturer has designed a
fine mesh screen material that provides added strength for fine mesh by weaving in larger
wire stands - about one every inch - among the finer strands to give strength while
helping maintain a lower percent open area that using finer strands provides. Other
manufacturers use screen backings instead.
EPA is aware of at least one facility in the U.S. that has installed Geiger screens (on a test
basis), but has found that the use of Geiger screens is much more widespread in Europe.
European Geiger screens often use screen mesh sizes in the 1 mm to 3 mm range, with
some as low as 0.5 mm and very few exceeding 4 mm. Many are installed on large
industrial rivers like the Rhine, which should have similar sediment and debris
characteristics as large U.S. rivers. European intake designs, however, are somewhat
different from U.S. designs in that they often use center-flow type screens and may have
a three step screening process.
Exhibit 6-14. Geiger screen (image from EPRI 2007)
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6.10.1 Technology Performance
Due to the relatively recent deployment of this technology, little performance data is
available. Preliminary results from the Mirant Potomac Generating Station have shown
impingement survival ranging from 0-100 percent depending on species. The most
numerous species included bluegill, channel catfish, spottail shiner, and white perch.
Representatives from EPRI and Mirant noted during the site visit at Potomac Generating
Station that testing of a fine mesh Geiger screen was underway.
6.10.2 Facility/Laboratory Examples
Mirant Potomac Generating Station
Mirant Potomac is located on the Potomac River in Virginia. The facility previously
used single-entry, single-exit traveling screens and installed Geiger screens on each of its
cooling water intake structures in 2004 to reduce the debris carryover experienced by
some of the vertical traveling screens. The new screens (mesh size of 3/8") have virtually
eliminated debris clogging in the condenser. However, due to high suspended sediment
loads in the source water, the facility still regularly shuts down to remove sediment
buildup in the condenser tubes. The Geiger screen for Unit 1 is also equipped with fish
buckets, a low pressure spray wash, and the ability to add a fish return trough. Data
generated in 2005 and 2006 showed mixed results. Bluegill impingement survival ranged
from 95-100 percent; channel catfish ranged from 50-94 percent; spottail shiner ranged
from 54-95 percent; and white perch ranged from 30-56 percent. The facility noted that
major runoff events may have compromised some of the sampling and that additional
data would need to be collected. (See DCN 10-6814.)
EPA conducted a site visit to Potomac in December 2007. See DCN 10-6512.
Donald C. Cook Nuclear Power Plant
Donald C. Cook Nuclear Power Plant is located in Michigan on Lake Michigan. From
October 1, 2003 through the first week of January 2004, the facility conducted a pilot test
of the Geiger Multidisc screens, using a drilled polyethylene disk, to minimize debris
carryover. (See DCN 10-681 l.)The plant tested the screens in two of 14 screens. The
screens functioned well and were able to be maintained at the deck level as opposed to
being transported off-site. Installation required about one week per screen and the retrofit
could be completed without downtime. No fish protection data was available.
6.11 Hydrolox screens
The Hydrolox screen is a hinged vertical traveling screen made of an engineered polymer
and consists of interconnected modules assembled in a bricklayed pattern for strength.
The Hydrolox screen has a smooth polymer surface and minimizes impingement
mortality through the use offish scoops," similar to fish buckets used in Ristroph
screens. Debris carryover is reduced by using "flights" which may be interchanged with
the fish scoops. Screen slot sizes are about Vi" or 6-7 mm. The Hydrolox screen fits into
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existing areas made for traditional vertical traveling screens. The modular components
allow maintenance to be performed on-site without having to replace the entire screen.
The engineered polymer is light, non-corrosive, and minimizes biofouling. This is a
relatively new technology that underwent laboratory testing by Alden Laboratories in
December of 2006.
6.11.1 Technology Performance
Results of laboratory testing conducted in 2006 show over 90 percent impingement
survival of golden shiner, common carp, bluegill, and channel catfish (See DCN 10-
6807.)
6.11.2 Facility Examples
Alden Laboratories Flume Testing
Alden Laboratories conducted impingement tests using a Hydrolox screen from July-
August 2006. Flume tests were conducted using a 4 ft wide by 12 ft high Hydrolox
screen installed perpendicular to the flow. The screening material was made of molded
plastic with slot openings of 0.25 in. by 0.30 in. Five freshwater species were used in the
experiment including the following: golden shiner, common carp, bluegill, striped bass,
and channel catfish. The screen was rotated at either 5 ft/min or 10 ft/min with water
flow velocities of 1 fps or 2 fps. Mortality rates were less than 10 percent for four of five
species (golden shiner, common carp, bluegill, and channel catfish), and injury and scale
loss were under 5 percent. Striped bass results seemed to be impacted by handling issues
as mortality rates for both the test group and the control group were higher but did not
seem to be caused by the Hydrolox screen (Alden 2006).
6.12 Beaudrey W Intake Protection (WIP) Screen
The Beaudrey W Intake Protection (WIP) screen is a screen wheel that faces the
incoming flow, screening both debris and organisms into a backwash pump that
transports debris and organisms back to the source water. The WIP screen is installed in
front of the recirculating water pumps and is easily retrofitted into existing traveling
screen openings and guides. All components are mounted either on the deck plate or the
WIP module itself. The WIP module can easily be raised for maintenance or inspection
without disassembling the screen (see DCN 10-6810 and 10-6606). This reduces costs
and no downtime is necessary.
Beaudrey's Fish Protection System (FPS) works as part of the WIP and includes a
Hidrostal® fish pump and backwash screens. The FPS also works with fine mesh
screens and can be installed at the same time as the screens or added/retrofitted later.
Fish are impinged for a maximum of two minutes, as the FPS operates at two revolutions
per minute. With the FPS/WIP screen combination (rotating screening wheel with no
chains or sprocket teeth), there is no carry-over of debris or fish. The system works well
for high, low, and mid-range water levels. Only two facilities in France currently use the
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FPS; however, there are also systems installed at facilities in Belgium and Portugal. The
FPS/WIP screen is being tested at one site in the US, but is not in widespread use.
6.12.1 Technology Performance
System operational tests of the Beaudrey FPSiM have shown strong capabilities to reduce
impingement mortality; tests have demonstrated mean survival rates in excess of 90
percent across a range offish species (see DCN 10-6810 and 10-6606). Preliminary
impingement survival sampling results from May 2008, for bluegill, fathead minnow, and
channel catfish ranged from 79.3 percent to 99.0 percent. A holding time of 48 hours
was used for the study.
6.12.2 Facility/Laboratory Examples
Omaha Public Power District - North Omaha Power Station, Nebraska
The North Omaha Power Station is located in North Omaha, Nebraska. The facility
completed a two-year pilot study (in coordination with EPRI) of the WIP/FPS screen in
2008 to study impingement mortality. Initial efforts were abandoned as researchers
discovered that the number offish normally impinged at the facility was too low to
provide meaningful data. The study then shifted to introduce fish directly in front of the
screen and study the subsequent impingement event. Hatchery fish representative of the
species found in the Missouri River were used, as well as "wild" fish caught in a seine net
near the facility. The study results showed impingement survival rates of 79 percent to
over 90 percent, with no statistically significant difference between fish exposed to the
screen versus the control group that was not exposed to any screens.
EPA conducted a site visit to North Omaha in March 2009. See DCN 10-6521.
6.13 Coarse Mesh Cylindrical Wedgewire
Cylindrical wedgewire screens, also called "V" screens or profile screens, unlike
traveling screens, are a passive intake system. Their performance is largely dictated by
conditions that are independent of the source water body's biological composition. The
typical design consists of wedge-shaped wires or bars welded to an internal cylindrical
frame that is mounted on a central intake pipe, with the entire structure submerged in the
source water body. When appropriate conditions are met, these screens exploit physical
and hydraulic exclusion mechanisms to achieve consistently high reductions in
impingement (and as a result, impingement mortality). Significant entrainment
reductions may also be observed when the screen slot size is small enough to exclude egg
and larval life stages (see below for a discussion of fine mesh wedgewire screens). Of
the 766 existing facility intakes that were reported in the detailed questionnaires, 60
intakes used wedgewire screens.
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Slot sizes for conventional traveling screens typically refer to a square opening (3/8" x
3/8") that is punched or woven into the screen face.25 Wedgewire screens are constructed
differently, however, with the slot size referring to the maximum distance between
longitudinally adjacent wires. These screens are designed to have a low, uniform
through-slot velocity (less than 0.5 feet per second) and typically have smaller slot sizes
than a coarse mesh traveling screen. The intake velocity quickly dissipates away from
the screen due to the cylindrical shape, thus creating a relatively small flow field in the
water body. This small flow field, together with optimal screen orientation, results in a
small system profile and minimizes the potential for contact between the screen and any
susceptible organisms that may come under the intake's hydraulic influence. In addition,
the ambient current crossflow (i.e., to maximize the sweeping velocity provided by the
waterbody) carries most free-floating organisms and debris past the screen, removing
organisms that are temporarily in contact with or pinned against the screen.26 As such,
screen orientation is also an important component of this technology's overall
performance. The low through-slot velocity in combination with the screen orientation
and cross current flow carries organisms away from the screen allowing them to avoid or
escape the intake current. Wedgewire screens may also employ cleaning and de-icing
systems, such as air-burst sparging or may be constructed with nickel or copper alloys to
discourage biofouling.
EPA believes that cylindrical wedgewire screens can be successfully employed by large
intake facilities under certain circumstances. Although many of the current installations
of this technology have been at smaller-capacity facilities, large water withdrawals can be
accommodated by multiple screen assemblies in the source waterbody. The limiting
factor for a larger facility may be the availability of sufficient accessible space near the
facility itself because additional screen assemblies consume more space on the waterbody
floor and might interfere with navigation or other uses of the waterbody. Consideration
of the impacts in terms of space and placement must be evaluated before selecting
wedgewire screens for deployment.
As with any intake structure, the presence of large debris poses a risk of damage to the
structure if not properly managed. Cylindrical wedgewire screens, because of their need
to be submerged in the water current away from shore, might be more susceptible to
debris interaction than other onshore technologies. Vendor engineers indicated that large
debris has been a concern at several of their existing installations, but the risk associated
with it has been effectively minimized by selecting the optimal site and constructing
debris diversion structures. Significant damage to a wedgewire screen is most likely to
occur from fast-moving submerged debris. Because wedgewire screens do not need to be
sited in the area with the fastest current, a less damage-prone area closer to shore or in a
cove or constructed embayment can be selected, provided it maintains a minimum
ambient current around the screen assembly. If placement in the main channel is
unavoidable, deflecting structures can be employed to prevent free-floating debris from
contacting the screen assembly. Typical installations of cylindrical wedgewire place
them roughly parallel to the direction of the current, exposing only the upstream nose to
25 See DCN 10-6604 for additional discussion on wedgewire slot sizes.
26 In fact, some hydrodynamic studies suggest that at a through-slot velocity of 0.5 fps, the sweeping flow
is dominant over the intake flow and can even reduce the number of organisms entrained.
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direct impacts with debris traveling downstream. EPA has noted several installations
where debris-deflecting nose cones have been installed to effectively eliminate the
damage risk associated with most debris. Apart from the damage that large debris can
cause, smaller debris, such as household trash or organic matter, can build up on the
screen surface, altering the through-slot velocity of the screen face and increasing the risk
of entrainment and/or impingement of target organisms. Again, selection of the optimal
location in the waterbody might be able to reduce the collection of debris on the structure.
Ideally, cylindrical wedgewire is located away from areas with high levels of submerged
aquatic vegetation (SAV) and out of known debris channels. Proper placement alone
may achieve the desired effect, although technological solutions also exist to physically
remove small debris and silt. Automated air-burst systems can be built into the screen
assembly and set to deliver a short burst of air from inside and below the structure.
Debris is removed from the screen face by the air burst and carried downstream and away
from the influence of the intake structure. Improvements to the air burst system have
eliminated the timed cleaning cycle and replaced it with one tied to a pressure differential
monitoring system.
Wedgewire screens are more likely to be placed closer to navigation channels than other
onshore technologies, thereby increasing the possibility of damage to the structure itself
or to a passing commercial ship or recreational boat. Because cylindrical wedgewire
screens need to be submerged at all times during operation, they are typically installed
closer to the waterbody floor than the surface. In a waterbody of sufficient depth, direct
contact with recreational or commercial vessels is unlikely. EPA notes that other
submerged structures (e.g., pipes, transmission lines) operate in many different
waterbodies and are properly delineated with acceptable navigational markers to prevent
accidents associated with trawling, dropping anchor, and similar activities. Such
precautions would likely be taken for a submerged wedgewire screen as well.
6.13.1 Technology Performance
Cylindrical wedgewire screens have not been used extensively as an impingement control
technology at a large number of facilities with large intake flows, but data describing
their performance at several installations, as well as laboratory evaluations, suggest a
strong potential to reduce impingement impacts when certain design and construction
criteria are satisfied. Data from limited studies have shown reductions in impingement of
near 100 percent.27
Other factors also influence this technology's overall performance and must be
considered during the system's design phase. Some data suggest that orienting the
screens perpendicular to the ambient flow can minimize contact injuries by reducing
screen-organism contact times, but at the expense of increasing the screen's profile. A
parallel orientation offers the smallest possible profile but may raise screen-organism
contact times as the organism has to travel the full length of the screen before returning to
27 In the 2004 Phase II rule, use of a wedgewire screen (under certain parameters) was deemed to be a pre-
approved technology for impingement requirements. This designation is no longer specifically included
under the proposed Existing Facilities rule, as installation of a wedgewire screen presumably already meets
the intake velocity criteria.
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the waterbody. The optimal orientation may be further influenced by the sensitivity and
abundance of the target species, as well as the probability for high debris loads in the
water body or the potential for frazil/sheet ice buildup.
6.13.2 Facility/Laboratory Examples
JH Campbell
JH Campbell is located on Lake Michigan in Michigan, with the intake for Unit 3 located
approximately 1,000 meters from shore at a depth of 10.7 meters. The cylindrical intake
structure has 9.5 mm mesh wedgewire screens and withdraws approximately 400 MGD.
Raw impingement data are not available, and EPA is not aware of a comprehensive study
evaluating the impingement reduction associated with the wedgewire screen system.
Comparative analyses using the impingement rates at the two other intake structures
(onshore intakes with conventional traveling screens) have shown that impingement of
emerald shiner, gizzard shad, smelt, yellow perch, and alewife associated with the
wedgewire screen intake has been effectively reduced to insignificant levels.
Maintenance issues have not been shown to be problematic at JH Campbell because of
the far offshore location in deep water and the periodic manual cleaning using water jets
to reduce biofouling.
Eddystone Generating Station
Eddystone Generating Station is located on the tidal portion of the Delaware River in
Pennsylvania. Units 1 and 2 were retrofitted to include wide-mesh wedgewire screens
and currently withdraw approximately 500 MGD from the Delaware River. Pre-
deployment data showed that over 3 million fish were impinged on the unmodified intake
structures during a single 20-month period. An automatic air burst system has been
installed to prevent biofouling and debris clogging from affecting the performance of the
screens. EPA has not been able to obtain biological data for the Eddystone wedgewire
screens but EPRI (2007) indicates that fish impingement has been eliminated.
EPA conducted a site visit to Eddystone in January 2008. See DCN 10-6507.
6.14 Barrier nets
Barrier nets are nets that encircle the point of water withdrawal from the bottom of the
water column to the surface that prevent fish and shellfish from coming in contact with
the intake structure and screens. Of the 766 existing facility intakes that were reported in
the detailed questionnaires, at least eight intakes employ a barrier net. Barrier net mesh
sizes vary depending on the intake configuration, level of debris loading, species to be
protected, and other factors such as the waterbody, velocity and tides, and typically range
from 4 mm to 32 mm (EPRI 1999). Relatively low through-technology velocities are
usually maintained through the nets because the area through which the water can flow is
usually large. Most barrier nets are designed to prevent impingement and do not prevent
entrainment due to the larger mesh size. Barrier nets are especially helpful in controlling
impingement during seasonal migrations offish and other organisms and to prevent
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impingement of shellfish on the intake traveling screen. Shellfish pose a unique
challenge to the operation of traveling screens because they affix themselves to the
screen; spray wash pressure is not able to remove them from the screen. Barrier nets are
often removed from the water in winter to prevent damage from ice and to make any
necessary repairs. In some cases, the use of barrier nets might be further limited by the
physical constraints and other uses of the waterbody, such as navigation.
6.14.1 Technology Performance
Barrier nets have clearly proven performance for controlling impingement (i.e., more
than 80 percent reductions over conventional screens without nets) in areas with limited
debris flows. High debris flows can cause significant damage to net systems. Biofouling
can also be a concern but may be addressed through adequate maintenance.
6.14.2 Facility Examples
JP Pulliam Station
The JP Pulliam Station is located on the Fox River in Wisconsin. Two separate nets with
6 mm mesh are deployed on opposite sides of a steel grid supporting structure. The
operation of a dual net system facilitates the cleaning and maintenance of the nets without
affecting the overall performance of the system. Under normal operations, nets are
rotated at least two times per week to facilitate cleaning and repair. The nets are typically
deployed when the ambient temperature of the intake canal exceeds 37°F. This usually
occurs between April 1 and December 1.
Studies undertaken during the first 2 years after deployment showed an overall net
deterrence rate of 36 percent for targeted species (noted only as commercially or
recreationally important, or forage species). Improvements to the system in subsequent
years consisted of a new bulkhead to ensure a better seal along the vertical edge of the net
and additional riprap along the base of the net to maintain the integrity of the seal along
the bottom of the net. The improvements resulted in a deterrence rate of 98 percent for
some species; no species performed at less than 85 percent. The overall effectiveness for
game species was better than 90 percent while forage species were deterred at a rate of 97
percent or better.
JR Whiting Plant
The JR Whiting Plant is located on Maumee Bay of Lake Erie in Michigan. A 3/8-inch
mesh barrier net was deployed in 1980 as part of a best technology available
determination by the Michigan Water Resources Commission. Estimates of impingement
reductions were based on counts offish impinged on the traveling screens inside the
barrier net. Counts in years after the deployment were compared to data from the year
immediately prior to the installation of the net when over 17 million fish were impinged.
Four years after deployment, annual impingement totals had fallen by 98 percent.
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Bowline Point
Bowline Point is located on the Hudson River in New York. A 150-foot long, 0.95-cm
mesh net has been deployed in a V-shaped configuration around the intake pump house.
The area of the river in which the intake is located has currents that are relatively
stagnant, thus limiting the stresses to which the net might be subjected. Relatively low
through-net velocities (0.5 ft/s) have been maintained across a large portion of the net
because of low debris loadings. Debris loads directly affecting the net were reduced by
including a debris boom outside the main net. An air bubbler was also added to the
system to reduce the buildup of ice during cold months. The facility has attempted to
evaluate the reduction in the rate of impingement by conducting various studies of the
fish populations inside and outside the barrier net. Initial data were used to compare
impingement rates from before and after deployment of the net and showed a deterrence
of 91 percent for targeted species (white perch, striped bass, rainbow smelt, alewife,
blueback herring, and American shad). In 1982 a population estimate determined that
approximately 230,000 striped bass were present in the embayment outside the net area.
A temporary mesh net was deployed across the embayment to prevent fish from leaving
the area. A 9-day study found that only 1.6 percent of the estimated 230,000 fish were
ultimately impinged on the traveling screens. A mark-recapture study that released
individual fish inside and outside the barrier net showed similar results, with more than
99 percent offish inside the net impinged and less than 3 percent offish outside the net
impinged. Gill net capture studies sought to estimate the relative population densities of
fish species inside and outside the net. The results agreed with those of previous studies,
showing that the net was maintaining a relatively low density offish inside the net as
compared to the outside.
Chalk Point
Chalk Point is located on the Patuxent River in Aquasco, Maryland. The facility began
using barrier nets in 1982 to address problems with blue crab impingement. Initially, a
single net was used, but a second net was later added to improve performance. Currently,
the outer net has a 1.25 inch square mesh and the inner net has a 0.75 inch square mesh.
Facility studies estimate a reduction in impingement of over 82 percent.
EPA conducted a site visit to Chalk Point in December 2007. See DCN 10-6504.
Dallman
Dallman is located on Lake Springfield in Springfield, Illinois. Since 1981, the facility
has used a barrier net at the mouth of its intake canal to reduce impingement at the
traveling screens. A study has shown a 90 percent reduction in impingement mortality.
6.15 Velocity Cap
Many offshore intakes are fitted with a velocity cap, a physical structure rising vertically
from the sea bottom and placed over the top of the intake pipe. Intake water is withdrawn
horizontally through openings in the velocity cap, converting the flow from a vertical
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§ 316(b) Existing Facilities Proposed Rule - TDD
direction to a horizontal one at the entrance to the intake (see Exhibits 6-15 and 6-16).
The horizontal flow provides a physiological trigger in fish to induce an avoidance
response thereby reducing impingement mortality. Velocity caps are also configured
with supports and bar spacing designed to prevent larger aquatic organisms from entering
the intake pipe and swimming to the forebay. Of the 766 existing facility intakes that
were reported in the detailed questionnaires, velocity caps are used by at least 13 intakes.
Velocity caps are sometimes used in combination with other technologies to optimize
performance; often, the offshore intake will send water to a forebay at the shoreline,
where a second CWIS with traditional traveling screens will further screen the cooling
water. Because velocity caps operate under the principle that the organisms can escape
the current, velocity caps alone do not offer a reduction in entrainment.
A far offshore technology, velocity caps may work to minimize impingement and
entrainment by virtue of their location. In some waterbodies, shoreline locations are
thought to have the potential for greater environmental impact because the water is
withdrawn from the most biologically productive areas. As such, some facilities elect to
employ an offshore intake to withdraw from less productive areas and further minimize
impingement and entrainment. Depth of the offshore intake is also a consideration as
deeper waters are often less biologically productive. Distance offshore and depth are
very site specific variables and must be carefully evaluated prior to siting the offshore
intake. The section on Intake Location later in this chapter discusses these factors. When
compared with a shoreline intake, an offshore location may reduce overall impingement
and entrainment rates but may also alter the impingement and entrainment species
profile.
Exhibit 6-15. Velocity cap diagram
I.3M
y-VELOCITY
CAP
HORIZONTAL INFLOW
V-0.5-l.5fp*
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Chapter 6: Technologies and Control Measures
Exhibit 6-16. Velocity caps prior to installation at Seabrook Generating Station
(Seabrook, NH)
6.15.1 Technology Performance
Velocity caps reduce the number offish drawn into intakes based on the concept that fish
tend to avoid rapid changes in horizontal flow. This technology does not reduce
entrainment of free-floating eggs and larvae, which are unable to distinguish flow
characteristics or have sufficient swimming ability to avoid them. Velocity caps are often
used in conjunction with other fish protection devices, so data is somewhat limited on
their performance when used alone.
At Huntington Beach and El Segundo in California, velocity caps have been found to
provide 80 to 90 percent reductions in fish entrapment.28 (See DCN 10-6603 for more
information.) At Seabrook Station in New Hampshire, the velocity cap on the offshore
intake has minimized the number of pelagic fish entrapped except for pollock. Two
facilities in England each have velocity caps on one of two intakes. At the Sizewell
Power Station, intake B has a velocity cap, which reduces impingement about 50 percent
compared to intake A. Similarly, at the Dungeness Power Station, intake B has a velocity
cap, which reduces impingement about by 62 percent compared to intake A.
Entrapment refers to the number of impingeable fish drawn into the velocity cap. Under most
circumstances, these organisms will eventually be impinged on the traveling screens at the facility.
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Impingement reductions observed at velocity cap facilities along the southern California
Bight have been generally been significant, with overall reductions ranging from 65 to 95
percent. These reduction values must be qualified, however, based on the methods used
to collect and analyze the samples as well as the species on which the reduction is
calculated. Earlier studies, such as the 1985 El Segundo report, tended to focus on
commercially and recreationally important species only, leaving aside forage species that
were presumed to be of little value at the time.
Velocity cap performance may vary significantly based on temporal or local factors.
Significant diurnal fluctuations in impingement rates have been observed with nighttime
performance often well below daytime values. At Huntington Beach Generating Station,
for example, observed impingement rates were 12 to 37 percent higher during nighttime
collection.
In addition, there are several factors that may influence velocity cap effectiveness and
may be unique to southern California's facilities:
• It is worth nothing that coastal waters along the southern California Bight are
subject to short and long-term periodic shifts in ocean temperatures that can affect
the number and composition of species potentially affected by the intake. Two
major climatic factors, the Pacific Decadal Oscillation (PDO) and the El Nino
Southern Oscillation (ENSO), can significantly raise or lower water temperatures
compared with long-term averages. During the El Nino phase of the ENSO,
warmer waters from the south generally replace the cooler water of the California
Current along the bight. During the La Nina phase, the pattern may shift and
result in colder than normal temperatures.
Each shift has the potential to alter the species mix in the vicinity of the intake,
with El Nino cycles driving cold water species further from shore and into areas
where they may be affected by the intakes. Effects of El Nino/La Nina events
may be magnified or moderated depending on the concurring phase of the PDO,
which may take 20-30 years to complete a full cycle. Temperatures may fluctuate
by 2.5° F or more during the event peaks. Comparisons between historical and
current information do show differences in species abundance, although a direct
correlation is difficult.
• Benefits of offshore intakes with respect to entrainment have not been studied in
as much detail as impingement, although recent sampling efforts by several
facilities offer a substantial data set from which entrainment reductions may be
calculated.
• Several of southern California's coastal facilities with offshore intakes are located
in areas with rocky substrates that support giant kelp forests. These kelp forests
support larger nursery and spawning areas offshore than are generally found off
the Atlantic coast.
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6.15.2 Facilities/Laboratory Examples
Huntington Beach Generating Station
Huntington Beach has one intake (equipped with a velocity cap) located 1,500 feet from
shore in Pacific Ocean. The intake is approximately 18 feet below Mean Lower Low
Water (MLLW) and 5 feet above intake riser. The initial study was conducted by the
University of Washington from 1978 through 1979. Velocity cap performance was
calculated by comparing the relative impingement rates of a capped versus uncapped
intake. This was done by reversing the intake and discharge locations, both of which are
located offshore in the same general area. Results from the comparative tests showed the
velocity cap was effective in reducing impingement by as much as 99 percent during the
day but as low as 53 percent at night. Overall effectiveness averaged 82 percent for all
sampling events regardless of time. As part of its NPDES permit requirements, the
facility has continued impingement monitoring during all heat treatments and
representative operating periods.
Entrainment analyses were not conducted at Huntington Beach in the late 1970s. Rather,
data collected at two other SCE facilities (Ormond Beach and SONGS) were used to
extrapolate Huntington Beach entrainment rates based on local conditions. Entrainment
performance was not calculated because source water references were not developed on
which any reduction could be based.
Huntington Beach conducted additional I&E sampling in 2003 and 2004 as part of its
relicensing agreement with the state. These samples included source water abundance
monitoring for both I&E at several reference monitoring stations located near the intake
and along the shoreline. Because these data were considered representative of current
conditions, Huntington Beach did not collect additional data in order to comply with
requirements for the Comprehensive Demonstration Study (CDS) under the 2004 Phase
II rule.
Various models were used to estimate entrainment impacts relative to the source water.
Depending on the target species, adult equivalent loss (AEL) model, fecundity
hindcasting (FH), and empirical transport model (ETM), methods were used to estimate
the percent mortality, which, in turn, provided the basis for acres of production foregone
(APF) estimates. Huntington Beach proposed to use this method to determine the
calculation baseline and any existing design credits under the 2004 Phase II rule.
Huntington Beach concluded that I&E impacts were not significant, although raw data
supporting this determination were not provided for review. Presumably, data collected
in 2003 and 2004 would be able to show entrainment rates relative to the source water
body abundance. Huntington Beach also conducted an entrainment survival study
(through condenser), but results are not yet available.
Scattergood Generating Station
Scattergood has on velocity cap located 1,600 feet from shore in Santa Monica Bay,
approximately 17 feet below MLLW. Site-specific evaluations of the velocity cap's
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impingement performance were first conducted in the early 1970s when a storm damaged
the original velocity cap. The cap was removed and, at the request of California
Department of Fish and Game, left off so as to allow a comparison of impingement rates
between the capped and uncapped intake. The facility estimated the velocity cap's
impingement reduction effectiveness at 83 percent compared with the uncapped intake.
As part of its NPDES permit requirements, the facility has continued impingement
monitoring during all heat treatments and representative operating periods. A 2006 study
again compared the performance of a capped versus uncapped intake by reversing the
operating flows; effectiveness was calculated at 95 percent using a biomass metric and
more than 97 percent based on abundance.
Entrainment analyses at Scattergood were first conducted in 1978 but only focused on
commercially and recreationally important species. As part of its 2004 Phase II CDS
compliance requirement, Scattergood conducted additional entrainment monitoring in
2006. Samples were collected from the intake structure as well as several reference
stations along the shoreline and in the vicinity of the intake structure. In contrast to the
1978 efforts, all taxa were identified as accurately as possible.
Various models were used to estimate entrainment impacts relative to the source water.
Depending on the target species, AEL, FH, and ETM methods were used to estimate the
percent mortality, which, in turn, provided the basis for APF estimates. Scattergood
proposed to use this method to determine the calculation baseline and any existing design
credits under the 2004 Phase II rule. An aggregate "percent reduction" value is not
explicitly presented in the final report, although raw data are available from both the
intake and reference stations that would enable such a determination.
Scattergood bases its discussion of entrainment impacts on guidelines set forth in EPA's
1977 guidance document, which categorizes AEI as significant or insignificant relative to
the known source populations. Scattergood concludes that the current intake's impacts
are insignificant.
EPA conducted a site visit to Scattergood in August 2009. See DCN 10-6545.
El Segundo Generating Station
El Segundo has two intakes with velocity caps, located 2,600 feet from shore in Santa
Monica Bay, but only one is currently operational. The velocity caps are approximately
15 feet below MLLW.
The original velocity cap effectiveness study at El Segundo was conducted in 1958 and
consisted of a full year of impingement monitoring before and after the velocity cap was
installed, showing an impingement reduction of 95 percent.
Entrainment analyses were not conducted at El Segundo in the late 1970s. Rather, data
collected at Ormond Beach were used to extrapolate El Segundo's entrainment rates
based on local conditions. These data are not considered reliable for El Segundo because
of the distance separating the two facilities (60 miles) and the sample collection and
analysis methods used that the time. Entrainment performance was not calculated
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because source water references were not developed on which a reduction could be
based.
El Segundo did conduct additional entrainment monitoring as part of its 2004 Phase II
9Q
CDS. Samples were collected in the intake forebay as well as at several reference
monitoring stations along the shoreline and in the vicinity of the intake. Total
entrainment values were estimated based on actual and design flows.
Various models were used to estimate entrainment impacts relative to the source water.
Depending on the target species, AEL, FH, and ETM methods were used to estimate the
percent mortality, which, in turn, provided the basis for APF estimates. El Segundo
proposed to use this method to determine the calculation baseline and any existing design
credits under the 2004 Phase II rule.
El Segundo bases its discussion of entrainment impacts on guidelines set forth in EPA's
1977 guidance document, which categorizes AEI as significant or insignificant relative to
the known source populations. El Segundo concludes that the current intake's impacts
are insignificant.
EPA conducted a site visit to El Segundo in September 2009. See DCN 10-6552.
6.16 Fine Mesh Screens
Both traveling screens and wedgewire screens can be designed to incorporate a fine
screen mesh to reduce entrainment.
6.16.1 Fine Mesh Traveling Screens
Fine mesh screens (mesh size of 5 mm or less30) are typically mounted on conventional
traveling screen systems and are used to exclude eggs, larvae, and juvenile forms offish
from intakes.31 Successful use of fine mesh screens is contingent on the application of
satisfactory handling and return systems to allow the safe return of impinged organisms
to the aquatic environment. Of the 766 existing facility intakes that were reported in the
detailed questionnaires, 43 intakes reported using fine mesh screens with a mesh size of 5
mm or less.
A retrofit with fine mesh screens is more complicated than one with coarse mesh because
the total through screen area will be decreased as a result of smaller screen slot sizes
(assuming the same intake structure size). Because the intake volume remains
unchanged, through-screen velocity will increase, perhaps significantly, unless the total
intake structure area is also increased. The former is generally undesirable, as intake
velocity is an important criterion in reducing impingement. The latter could result in a
29 The velocity cap transports water from offshore to a forebay, which is an area of water storage from
which conventional intake technologies (such as traveling screens and circulating water pumps) withdraw
cooling water for use in the facility.
30 There is no widely accepted definition of "fine mesh." EPA's industrial surveys in 2000 used 5mm as
the threshold.
31 Fine mesh screen overlays can also be used to attach to a coarse mesh screen.
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longer downtime period than for retrofitting to modified coarse mesh traveling screens.
For example, replacing coarse mesh screens with a 68 percent open area with fine mesh
screens of the same size with a 44 percent open area will increase the through-screen
velocity by a factor of 1.55. If the retrofit analysis estimated a total screen area required
that is greater than what is available at the existing intake (i.e., the compliance screen
area factor is greater than 1.0), a new intake with a larger screen area would be needed.
EPA assumed the new larger intake would have a through-screen velocity of 1.0 fps
when estimating the screen area factor and technology costs for a new larger intake.32
The size and cost of this new screen technology are directly related to the required screen
surface area.33 Velocity increases beyond a certain range would be unacceptable because
they might increase impingement of other organisms and would increase the mortality of
eggs and larvae captured on the fine mesh screen panels.
Fouling and clogging concerns may be more pronounced with fine mesh screens as well.
With a smaller screen open area, the effects of fouling on through-screen velocity (and
flow volume provided for cooling) may be affected.
As the desired mesh size decreases (i.e., as the screen compliance factor increases), the
potential for problems associated with the availability of space to construct a larger intake
increases. This is especially true for shore-based intake technologies, since water depth
is generally relatively shallow, thereby requiring any screen expansion to cover a
proportionally longer length of shoreline. The availability of additional shore space at
many existing intakes may be limited due to existing structures and other
considerations.34 See DCN 10-6601 for further information on fine mesh screen
feasibility, particularly with respect to debris handling and screen expansion.
EPA analyzed several options for fine mesh screens (see Chapter 7 and the preamble) but
ultimately did not adopt them as the technology basis. In its analysis, EPA found that
many model facilities would be required to significantly expand their intake structures to
accommodate the fine mesh screens and maintain a 0.5 fps through-screen velocity; in
some cases, as many as 68% of facilities would need to expand the size of their intake by
more than five times, leading EPA to believe that fine mesh screens would not be an
available technology at those sites.
6.16.1.1 Technology Performance
Fine mesh traveling screens designed to reduce entrainment impacts have been used at a
few large intake facilities, but data describing their performance is limited. Data
demonstrates that entrainment typically decreases as mesh size decreases, particularly for
eggs. In an August 2008 presentation to EPA, EPRI stated that field deployment of fine
mesh traveling screens with favorable screen operating performance (i.e., can properly
32 The design through-screen velocity of 1.0 fps for new expanded intakes is not a regulatory requirement;
it simply reflects a best professional judgment (BPJ) design standard for a new intake structure. In part,
EPA assumed that a new facility would be designed using a more conservative through-screen velocity to
avoid operational problems involving debris accumulation
33 See Chapter 8 of the TDD, which describes the costing model used for the proposed rule. Module 3
contains the costs for expanding an existing intake structure.
34
Examples might include limited ownership of shoreline property or conflicting uses of the shoreline.
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handle debris loading) included eight power plant sites in the US (Dixon 2008).35 These
plants represent various waterbody types, flows, fuel types, configurations, and locations
throughout the country. The wide variety of operating conditions at facilities with fine
mesh traveling screens suggests that with proper design and operation, these screens are
technically feasible at most facilities.36
For the 2004 Phase II rule, EPA assumed that the mortality of entrained organisms would
be 100 percent. However, as mesh sizes are reduced to prevent entrainment,3? more and
more entrainables become impinged on the screens (i.e., "converted" from entrainable to
impingeable) and subjected to spray washes and return along with larger impinged
organisms as well as debris from the screens. Under the 2004 Phase II rule, these
"converts" would be classified as a reduction in entrainment, since the entrainment
performance standard simply required a reduction in the number (or mass) of entrained
organisms entering the cooling system. However, for some facilities the low survival rate
of converts resulted in the facility have difficulty complying with the impingement
mortality limitations. By comparison, the performance standard for impingement was
measured as impingement mortality. Organisms that were impinged (i.e., excluded) from
the cooling water intake structure were typically washed into a return system and sent
back to the source water. In this case, impingement mortality is an appropriate measure
of the biological performance of the technology.
Through EPA's review of control technologies, the Agency found that the survival of
"converts" on fine mesh screens was very poor, and in some extreme cases comparable to
the extremely low survival of entrained organisms that are allowed to pass entirely
OO
through the facility. More specifically, EPA found that nearly 100 percent of eggs were
entrained unless the mesh slot size was less than 2 mm, and mortality of eggs "converted"
to impingement ranged from 20 to 30 percent.39 More telling, the mortality of larvae
collected from a fine mesh screen was usually greater than 80 percent. As a result, a
facility with entrainment exclusion technologies such as fine mesh screens could
approach 90 percent performance, but the subsequent survival of these organisms ranged
from 0 to 52 percent (mean value of 12 percent survival) depending on life stage and
species, and the facility's impingement mortality rates increased.
Exhibit 6-17 illustrates this concept. Organisms of all sizes are exposed to the screen
face. Larger organisms (i.e., those that would be impinged by any mesh size) are
impinged and sent to the fish return. "Converts" (i.e., those that would pass through a
35 The facilities listed were Hartford Generating Project, Barney Davis, Indian Point, Big Bend, Brunswick,
Somerset, Dunkirk, and Prairie Island.
36 Further, the technology vendors stated that the distribution of fine mesh traveling screens has been
limited due to the fact that few facilities have been required to install fine mesh screens. EPRI also
concluded that the potential for future use of fine mesh screens is favorable, as handling procedures and
screen designs have continued to improve (Dixon 2008).
37 Fine mesh screens were considered to be one technology that could be used to meet the entrainment
performance standards under the 2004 Phase II rule. EPA also reviewed performance data for screens with
mesh sizes as small as 0.5 mm, as described in Chapter 11 of this TDD.
38 Through-plant entrainment survival has been studied extensively, with EPPJ's Review of Entrainment
Survival Studies being amongst the most comprehensive. See DCN 2-017A-R7 from the Phase I docket.
39 See Chapter 11 of this TDD for details on these analyses.
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§ 316(b) Existing Facilities Proposed Rule - TDD
40
coarse mesh screen) are also impinged and sent to the fish return. Small organisms and
eggs that would not be impinged by any mesh size pass through the screen and are
entrained.
Exhibit 6-17. Illustration of Fine Mesh Screen Operation and "Converts'
Pumps
So, a facility that simply excluded entrainable organisms (with no attention being paid to
whether they survive or not) could be deemed to have met its entrainment requirements
under the 2004 Phase II rule, when in fact it may be causing the same level of mortality
as a facility with no entrainment controls at all. EPA's current review of entrainment and
entrainment mortality shows the same trends identified in the research reviews by EPRI
(see DCNs 10-6802 and 6-5004B), namely that entrainment decreases with increasing
larval length, increased sweeping flow, decreasing slot (intake) velocity, and decreasing
slot width.41
A representative for Eimco (a traveling screen vendor) stated that 0.5 mm fine mesh
requires low screen velocities (i.e., approximately 0.5 fps) and that retrofitting a high
velocity traveling screen with 0.5 mm mesh would be very difficult on large rivers such
as the Mississippi and Missouri Rivers (Gathright 2008). The Missouri River is known
for having high levels of suspended sediment, which can create problems in "blinding" of
the intake screens. Blinding of the screens occurs when the sediment and debris
40 Exhibit 6-15 also shows a screen applied to the fish return. Consistent with EPA's definition of
impingement in the proposed rule, this symbolizes that impingement standards would be applied to those
fish that would have been impinged by a 3/8" screen.
41 See Chapter 11 of this TDD for additional details.
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accumulate on the screens at a rapid rate. If increased screen rotation and backwashing is
not sufficient to remove the sediment, then the desired cooling pumping rate may not be
sustained, which would force the facility to reduce the pumping rate or cease
withdrawals, leading to a reduction (or cessation) of power generation. Typically, the
problem of screen blinding in rivers with high sediment loading diminishes as the screen
mesh size approaches 1.0 mm and does not present a problem if 2.0 mm screens are used
(Gathright 2008).
The primary reason for the difference in performance of screens with different mesh sizes
is due to the typical distribution of sand particle size in the river water. In a study of sand
grain size distribution from the Fraser River Port in British Columbia, 90 percent of the
sand particles were < 0.5 mm in size, with the percent content increasing rapidly below
0.5 mm (see DCN 10-6601). The particle size distribution graph shows that 0.5 mm was
somewhat of an inflection point where grain size content diminished more gradually as
the size increased, approaching 0 percent at 2 mm. Thus, a screen with a mesh size of
0.5 mm would capture a significant portion of the suspended material, while a screen
with a mesh size near 2.0 mm would capture very little of it.
Problems with larger, less-dense debris particles such as leaves will not be affected as
much by mesh size, since such debris particles will be captured on the screen regardless
of mesh size and, therefore, no changes in operation would be expected with finer mesh.
EPA recognizes that high sediment waterbodies pose a challenge for fine mesh screens.
However, a mesh size of 2.0 mm has been shown to be effective in handling the high
sediment loads. EPA also acknowledges that facilities located on high sediment rivers
face constant challenges related to sediment, as existing intake screens may become
clogged or suffer premature failure or condenser tubes may require more frequent
cleaning.
6.16.1.2 Facility Examples
Big Bend
The most significant example of long-term use of fine-mesh screens has been at the Big
Bend Power Plant in the Tampa Bay area. The facility has an intake canal with 0.5 mm
mesh Ristroph screens that are used seasonally on the intakes for Units 3 and 4. During
the mid-1980s when the screens were initially installed, their efficiency in reducing I&E
mortality was highly variable (EPRI2007). The operator, Florida Power & Light (FPL)
evaluated different approach velocities and screen rotational speeds. In addition, FPL
recognized that frequent maintenance (manual cleaning) was necessary to avoid
biofouling. By 1988, system performance had improved greatly. The system's
efficiency in screening fish eggs (primary species are drum and bay anchovy) exceeded
95 percent,42 with 80 percent latent survival for drum and 93 percent for bay anchovy.
For larvae (primary species are drum, bay anchovy, blennies, and gobies), screening
42 The 95 percent value reflects the exclusion rate, the percentage of organisms prevented from entering the
cooling water system and does not address entrainment mortality. The same is true for the following
sentence which cites a screening efficiency of 85 percent, again an exclusion rate.
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efficiency was 86 percent, with 65 percent latent survival for drum and 66 percent for bay
anchovy. Note that latent survival in control samples was also approximately 60 percent.
Although more recent data are generally not available, the screens continue to operate
successfully at Big Bend in an estuarine environment with proper maintenance.
EPA conducted a site visit to Big Bend in March 2008. See DCN 10-6502.
Other Facilities
Although egg and larvae entrainment performance data are not available, fine mesh
(0.5 mm) Passavant screens (single entry/double exit) have been used successfully in a
marine environment at the Barney Davis Station in Corpus Christi, Texas. Impingement
data for this facility show an overall 86 percent initial survival rate for bay anchovy,
menhaden, Atlantic croaker, killfish, spot, silverside, and shrimp. EPA conducted a site
visit to Barney Davis in March 2008. See DCN 10-6500.
Additional full-scale performance data for fine-mesh screens at large power stations are
generally not available. However, some data are available from limited use or study at
several sites and from laboratory and pilot-scale tests. Seasonal use of fine mesh on two
of four screens at the Brunswick Power Plant in North Carolina has shown 84 percent
reduction in entrainment compared to the conventional screen systems. Similar results
were obtained during pilot testing of 1 mm screens at the Chalk Point Generating Station
in Maryland.43 At the Kintigh Generating Station in New Jersey, pilot testing indicated
that 1 mm screens provided 2 to 35 times the reduction in entrainment over conventional
9.5 mm screens. Finally, Tennessee Valley Authority (TVA) pilot-scale studies
performed in the 1970s showed reductions in striped bass larvae entrainment of up to
99 percent for a 0.5 mm screen and 75 and 70 percent for 0.97 mm and 1.3 mm screens,
respectively. A full-scale test by TVA at the John Sevier Plant showed less than half as
many larvae entrained with a 0.5 mm screen than with 1- and 2 mm screens combined.
6.16.2 Fine Mesh Wedgewire Screens
Fine mesh wedgewire functions in the same way as coarse mesh wedgewire, but due to
the reduced slot size also acts to exclude smaller organisms (including larvae and eggs),
reducing entrainment. Physical exclusion is accomplished by designing the screens with
a slot size that will prevent the entrainment of the smallest target taxa or life stage. In
general, a smaller slot size will translate into larger or more numerous screen assemblies
in order to maintain the desired through-slot velocity. Furthermore, small slots increase
the debris clogging potential and associated maintenance needs.
6.16.2.1 Technology Performance
Fine-mesh applications (those designed to target eggs and larvae) have shown high
potential to reduce entrainment if intake velocities are maintained. Reductions in
43
EPA conducted site visits to Brunswick and Chalk Point in January 2008 and December 2007,
respectively. See DCN 10-6504.
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entrainment exclusion of approximately 90 percent have been demonstrated. Due to
difficulty in collecting entrainables from a fine mesh wedgewire screen, entrainment
survival is not known.
6.16.2.2 Facility Examples
Laboratory Evaluation
EPRI published (May 2003; see DCN 6-5004B) the results of a laboratory evaluation of
wedgewire screens under controlled conditions in the Alden Research Laboratory Fish
Testing Facility. A principal aim of the study was to identify the important factors that
influence the relative rates of impingement and entrainment associated with wedgewire
screens. The study evaluated characteristics such as slot size, through-slot velocity, and
the velocity of ambient currents that could best carry organisms and debris past the
screen. When each of the characteristics was optimized, wedgewire screen use became
increasingly effective as an impingement reduction technology; in certain circumstances
it could be used to reduce the entrainment of eggs and larvae. EPRI notes that large
reductions in impingement and entrainment might occur even when all characteristics are
not optimized. Localized conditions unique to a particular facility, which were not
represented in laboratory testing, might also enable successful deployment. The study
cautions that the available data are not sufficient to determine the biological and
engineering factors that would need to be optimized, and in what manner, for future
applications of wedgewire screens.
Slot sizes of 0.5, 1.0, and 2.0 mm were each evaluated at two different through-slot
velocities (0.15 and 0.30 m/s) and three different channel velocities (0.08, 0.15, and
0.30 m/s, corresponding to 0.25, 0.5, and 1.0 ft/sec) to determine the impingement and
entrainment rates offish eggs and larvae. Screen open area increased from 24.7 percent
for the 0.5 mm screens to 56.8 percent for 2.0 mm screens. The study evaluated eight
species (striped bass, winter flounder, yellow perch, rainbow smelt, common carp, white
sucker, alewife, and bluegill) because of their presence in a variety of waterbody types
and their history of entrainment and impingement at many facilities. Larvae were studied
for all species except alewife, while eggs were studied for striped bass, white sucker, and
alewife. (Surrogate, or artificial, eggs of a similar size and buoyancy substituted for live
striped bass eggs.) Individual tests followed a rigorous protocol to count and label all
fish eggs and larvae prior to their introduction into the testing facility. Approach and
through-screen velocities in the flume were verified, and the collection nets used to
recapture organisms that bypassed the structure or were entrained were cleaned and
secured. Fish and eggs were released at a point upstream of the wedgewire screen
selected to deliver the organisms at the centerline of the screens, which maximized the
exposure of the eggs and larvae to the influence of the screen. The number of entrained
organisms was estimated by counting all eggs and larvae captured on the entrainment
collection net. Impinged organisms were counted by way of a plexiglass window and
video camera setup.
In addition to the evaluations conducted with biological samples, Alden Laboratories
developed a Computational Fluid Dynamics (CFD) model to evaluate the hydrodynamic
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characteristics associated with wedgewire screens. The CFD model analyzed the effects
of approach velocity and through-screen velocities on the velocity distributions around
the screen assemblies. Using the data gathered from the CFD evaluation, engineers were
able to approximate the "zone of influence" around the wedgewire screen assembly under
different flow conditions and estimate any influence on flow patterns exerted by multiple
screen assemblies located in close proximity to each other.
The results of both the biological evaluation and the CFD model evaluation support many
of the conclusions reached by other wedgewire screen studies, as well as in situ anecdotal
evidence. In general, the lower impingement rates were achieved with larger slot sizes
(1.0 to 2.0 mm), lower through-screen velocities, and higher channel velocities.
Similarly, the lowest entrainment rates were seen with low through-screen velocities and
higher channel velocities, although the lowest entrainment rates were achieved with
smaller slot sizes (0.5 mm). Overall impingement reductions reached as high as 100
percent under optimal conditions, and entrainment reductions approached 90 percent. It
should be noted that the highest reductions for impingement and entrainment were not
achieved under the same conditions. Results from the biological evaluation generally
agree with the predictions from the CFD model: the higher channel velocities, when
coupled with lower through-screen velocities, would result in the highest rate of
protection for the target organisms.
Other Facilities
Other plants with lower intake flows have also installed wedgewire screens, but there are
limited biological performance data for these facilities. Unit 1 at the Cope Generating
Station in South Carolina is a closed-cycle unit that withdraws about 6 MOD through a
2 mm wedgewire screen; however, no biological data are available. Westchester RESCO
(design flow of 55 MGD) uses a wedgewire screen with 0.5mm slot size; however, no
studies relating to reductions in impingement and entrainment have been conducted. The
Logan Generating Station in New Jersey withdraws 19 MGD from the Delaware River
through a 1 mm wedgewire screen. Entrainment data show 90 percent less entrainment
of larvae and eggs than conventional screens. No impingement data are available.44
Wedgewire screens have been considered or tested for several other large facilities. In
situ testing of 1 and 2mm wedgewire screens was performed in the St. John River for the
Seminole Generating Station Units 1 and 2 in Florida in the late 1970s. This testing
showed virtually no impingement and 99 and 62 percent reductions in larvae entrainment
for the 1 mm and 2 mm screens, respectively, over conventional screen (9.5 mm)
systems. In 1982 and 1983 the State of Maryland conducted testing using 1, 2, and 3 mm
wedgewire screens at the Chalk Point Generating Station, which withdraws water from
the Patuxent River in Maryland. The 1 mm wedgewire screens were found to reduce
entrainment by 80 percent. No impingement data were available. Some biofouling and
clogging were observed during the tests. In the late 1970s, Delmarva Power and Light
conducted laboratory testing of fine-mesh wedgewire screens for the proposed 1,540 MW
Summit Power Plant. This testing showed that entrainment offish eggs (including
44 EPA conducted site visits to Westchester RESCO and Logan in April 2008 and January 2008,
respectively. See DCN 10-6517 and DCN 10-6509.
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striped bass eggs) could effectively be prevented with slot widths of 1 mm or less, while
impingement mortality was expected to be less than 5 percent. Actual field testing in the
brackish water of the proposed intake canal required the screens to be removed and
cleaned as often as once every 3 weeks.
6.17 Aquatic Filter Barrier
Aquatic Filter (or microfiltration) Barriers (AFBs), also known under the trade name
"Gunderboom," are similar to barrier nets in that they extend throughout the area of water
withdrawal from the bottom of the water column to the surface (see Exhibit 6-18).
However, AFBs consists of fabric panels with very small pores (<20 microns or
0.02 mm) manufactured as a matting of minute unwoven fibers. The fullwater-depth
filter curtain is suspended by flotation billets at the surface of the water and anchored to
the substrate below. Gunderboom systems also employ an automated "air burst" system
to periodically shake the material and pass air bubbles through the curtain system to clean
off sediment buildup and release any other material back into the water column. AFBs
reduce both impingement and entrainment because they present a physical barrier to all
life stages. These systems can be floating, flexible, or fixed. Because these systems
usually have such a large surface area, the velocities maintained at the face of the
permeable curtain are very low. EPA was aware of one facility that uses an AFB, but
notes that this facility recently ceased operations for reasons unrelated to its use of AFB.
Exhibit 6-18. Gunderboom at Lovett Generating
Station (image from Gunderboom)4
45 http://www.gunderboom.com/images/lovett.ipg
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6.17.1 Technology Performance
At this juncture, the only facility where the Gunderboom was used at a full-scale level is
the Lovett Generating Station along the Hudson River in New York, where pilot testing
began in the mid-1990s. Initial testing at that facility showed significant potential for
reducing entrainment. Entrainment reductions of up to 82 percent were observed for eggs
and larvae, and these levels were maintained for extended month-to-month periods from
1999 through 2001. At Lovett, some operational difficulties affected long-term
performance. These difficulties, including tearing, overtopping, and plugging/clogging,
were addressed, to a large extent, through subsequent design modifications.
Gunderboom, Inc. specifically has designed and installed a microburst cleaning system
to remove particulates. As noted above, the Lovett Generating Station recently closed
operations.
Each of the challenges encountered at Lovett could be of significant concern at marine
sites, as these have higher wave action and debris flows. Gunderboom systems have been
successfully deployed in marine conditions to prevent migration of particulates and
bacteria, including in areas with waves up to 5 feet. The Gunderboom system is being
tested for potential use at the Contra Costa Plant along the San Joaquin River (a tidal
river) in northern California. An additional question related to the utility of the
Gunderboom and other microfiltration systems is sizing and the physical limitations and
other uses of the source waterbody. With a 20-micron mesh, 144 MGD and 288 MGD
intakes would require filter systems 500 and 1,000 feet long (assuming a 20-foot depth).
In some locations, this may preclude the successful deployment of the system because of
space limitations or conflicts with other waterbody uses.
AFBs have been installed at other sites for sediment control and exclusion of small
debris. More recent improvements to AFBs have reduced the effect of wave action and
debris (see DCN 10-6830).
6.17.2 Facilities Examples
As described above, the technology was installed at the Lovett Generating Station which
has ceased operations. EPA is not aware of any other existing industrial facilities
employing an AFB.
6.18 Other Technologies and Operational Measures
6.18.1 Reduce Intake Velocity
The relationship between intake velocity and impingement is well-established since
EPA's Phase I rule (66 FR 65256). Impingement mortality can be greatly reduced by
reducing the through-screen velocity in any screen. Reducing the through-screen velocity
to 0.5 ft/sec or less reduces impingement of most species by 96 percent because it allows
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them to escape the intake current.46 (See DCN 2-028 A EPRI Technical Evaluation of the
Utility of Intake Approach Velocity as an Indicator of Potential Adverse Environmental
Impact Under Clean Water Act 316(b)). As a result, many existing facilities have
designed and operate their modified traveling screens or wedgewire screens so as not to
exceed a through-screen velocity of 0.5 ft/sec.
Reducing the intake velocity generally does not similarly reduce entrainment.
6.18.2 Substratum Intakes
Studies and pilot projects are being conducted to investigate the viability of subsurface or
substratum cooling water intake structures, also known as filter beds. Historically,
substratum intakes have only been seriously considered for low flow facilities, smaller
than 1 MOD. Desalination drinking water facilities appear to be the predominant
industry utilizing substratum intakes in their operations. While extant in the United
States, operation of desalination facilities has so far been concentrated in Europe, North
Africa, and the Middle East. Some non-desalination drinking water facilities also use
substratum water intakes. These facilities most commonly make use of vertical or
horizontal beach wells, which are shallow shoreline intake wells that use the overlying
rock or sand layers as a filter medium. Early investigations for use as cooling water
intake structures have yielded positive results, including 100 percent reduction of
impingement and entrainment. See DCN 10-6609 for more information.
A pilot study using a substratum intake was planned for 2008 for a site in New York to
withdraw about 245 MGD to operate a 400 MW power plant. The substratum intake was
expected to eliminate impingement and entrainment, and offer other benefits by reducing
operations and maintenance costs, requiring minimal downtime at installation, and
reducing fuel use in the summer. No information about the progress or results of this
pilot study is currently available.
6.18.3 Louvers
Louver systems are comprised of a series of vertical panels placed at an angle to the
direction of the flow (typically 15 to 20 degrees). Each panel is placed at an angle of
90 degrees to the direction of the flow (Hadderingh, 1979). The louver panels provide an
abrupt change in both the flow direction and velocity. This creates a barrier that fish can
sense and avoid. Once the change in flow/velocity is sensed by fish, they typically align
with the direction of the current and move away laterally from the turbulence. This
behavior further guides fish into a current created by the system, which is parallel to the
face of the louvers. This current pulls the fish along the line of the louvers until they
enter a fish bypass or other fish handling device at the end of the louver line. The louvers
may be either fixed or rotated similar to a traveling screen. Flow straighteners are
frequently placed behind the louver systems.
46 66 FR 65274
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In its 2007 Fish Protection at Cooling Water Intake Structures: A Technical Reference
Manual, EPRI concluded that the technology has produced variable results, but that well-
performing louvers can divert over 80 percent offish to a bypass. Louvers have also not
been widely employed at power plant intakes; most installations are at hydroelectric or
irrigation facilities.
While showing some promise for diverting fish (thereby reducing impingement), louvers
have not been widely used at power plants and have a very limited history of successful
deployment. Therefore, EPA has determined that this technology is unlikely to be
utilized by many existing facilities.
6.18.4 Intake Location
There are certain areas within every waterbody with increased biological productivity,
and therefore where the potential for I&E of organisms is higher. In large lakes and
reservoirs, the littoral zone (the shore zone areas where light penetrates to the bottom)
serves as the principal spawning and nursery area for most species of freshwater fish and
is considered one of the most productive areas of the waterbody. Fish of this zone
typically follow a spawning strategy wherein eggs are deposited in prepared nests, on the
bottom, or are attached to submerged substrates where they incubate and hatch. As the
larvae mature, some species disperse to the open water regions, whereas many others
complete their life cycle in the littoral zone. Clearly, the impact potential for intakes
located in the littoral zone of lakes and reservoirs is high. The profundal zone of lakes
and reservoirs is the deeper, colder area of the waterbody. Rooted plants are absent
because of insufficient light, and for the same reason, primary productivity is minimal. A
well-oxygenated profundal zone can support benthic macroinvertebrates and cold-water
fish; however, most of the fish species seek shallower areas to spawn (either in littoral
areas or in adjacent streams and rivers). Use of the deepest open water region of a lake or
reservoir (e.g., within the profundal zone) as a source of cooling water typically offers
lower I&E impact potential than use of littoral zone waters.
As with lakes and reservoirs, rivers are managed for numerous benefits, which include
sustainable and robust fisheries. Unlike lakes and reservoirs, the hydrodynamics of rivers
typically result in a mixed water column and overall unidirectional flow. There are many
similarities in the reproductive strategies of shoreline fish populations in rivers and the
reproductive strategies offish within the littoral zone of lakes and reservoirs. Planktonic
movement of eggs, larvae, post larvae, and early juvenile organisms along the shore zone
is generally limited to relatively short distances. As a result, the shore zone placement of
CWISs in rivers might potentially impact local spawning populations offish. The impact
potential associated with entrainment might be diminished if the main source of cooling
water is recruited from near the bottom strata of the open water channel region of the
river. With such an intake configuration, entrainment of shore zone eggs and larvae, as
well as the near-surface drift community of ichthyoplankton, is minimized. Impacts
could also be minimized by controlling the timing and frequency of withdrawals from
rivers. In temperate regions, the number of entrainable or impingeable organisms of
rivers increases during spring and summer (when many riverine fishes reproduce). The
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number of eggs and larvae peak at that time, whereas entrainment potential during the
remainder of the year can be minimal.
In estuaries, species distribution and abundance are determined by a number of physical
and chemical attributes, including geographic location, estuary origin (or type), salinity,
temperature, oxygen, circulation (currents), and substrate. These factors, in conjunction
with the degree of vertical and horizontal stratification (mixing) in the estuary, help
dictate the spatial distribution and movement of estuarine organisms. With local
knowledge of these characteristics, however, the entrainment effects of a CWIS could be
minimized by adjusting the intake design to areas (e.g., depths) least likely to affect
concentrated numbers and species of organisms. In oceans, nearshore coastal waters are
typically the most biologically productive areas. The euphotic zone (zone light available
for photosynthesis) typically does not extend beyond the first 100 meters (328 feet) of
depth. Therefore, inshore waters are generally more productive due to photosynthetic
activity and due to the input from estuaries and runoff of nutrients from land.
During the development of the Phase III rule, EPA obtained data on densities of
ichthyoplankton in the Gulf of Mexico from the Southeast Area Monitoring and
Assessment Program (SEAMAP). This long-term sampling program collects information
on the density offish larvae and eggs throughout the Gulf of Mexico.47 EPA's analysis
showed that in general, ichthyoplankton densities are highest at sampling stations in the
shallower regions of the Gulf and lowest at sampling stations in the deepest regions.
Over 600 different fish taxa were identified in the SEAMAP samples, including species
of commercial and recreational value.
There are only limited published data, however, quantifying the locational differences in
I&E rates at individual power plants. Some information, however, is available for
selected sites. For example:
• For the St. Lucie plant in Florida, EPA Region 4 permitted the use of a once
through cooling system instead of closed-cycle cooling by locating the outfall
1,200 feet offshore (with a velocity cap) in the Atlantic Ocean. This approach
avoided impacts on the biologically sensitive Indian River estuary.
• In Entrainment of Fish Larvae and Eggs on the Great Lakes, with Special
Reference to the D. C. Cook Nuclear Plant, Southeastern Lake Michigan (1976),
researchers noted that larval abundance is greatest within the area from the
12.2-m (40-ft) contour to shore in Lake Michigan and that the abundance of
larvae tends to decrease as one proceeds deeper and farther offshore. This finding
led to the suggestion of locating CWISs in deep waters.
• During biological studies near the Fort Calhoun Power Station along the Missouri
River, results of transect studies indicated significantly higher fish larvae densities
along the cutting bank of the river, adjacent to the station's intake structure.
Densities were generally were lowest in the middle of the channel.
47 EPA analyzed SEAMAP data in considering requirements for offshore facilities in the Phase III rule.
While this data is not directly relevant to existing facilities subject to the proposed rule, it does offer similar
insights to the importance of intake location. See 71 FR 35013.
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• Wisconsin Energy's Elm Road facility was recently constructed with a submerged
intake 1.5 miles offshore at a depth of 43 feet. The facility is using coarse mesh
cylindrical wedgewire screens with a through-slot velocity of 0.5 fps.
As discussed above, intake location can play an important role in determining the
potential for impingement and entrainment. However, for existing facilities, changing the
intake location is very limited in practice; many facilities simply do not have the option
available to them and when available, intake relocation tends to be among the most
expensive alternatives. Selecting an appropriate intake location is best considered when
siting a new intake or new facility. EPA included retrofit costs for a limited number of
facilities to relocate to a new location (with a new wedgewire screen) but did not consider
this approach for national requirements. See chapter 12 for more information on distance
and depth of offshore intakes on performance in reducing impingement and entrainment.
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6.19 References
California Ocean Protection Council. 2008. California's Coastal Power Plants: Alternate
Cooling System Analysis. Available at
http://www.opc.ca.gov/webmaster/ftp/project_pages/OTC/engineering%20studv/C
A_Power_Plant_Analysis_Complete.pdf. Accessed March 2011.
Dixon, D. and J. Black. 2008. Fine-mesh Traveling Screens. Presentation for EPRI-EPA
Meeting. August 26, 2008.
EEA, Inc. 2005. Keyspan Generation LLC studies the substratum intake system: An
Innovative water intake system for power generation facilities. Environmental
Consulting Insights Newsletter. Spring, 2005.
Electric Power Research Institute. 2009. Beaudrey Water Intake Protection (WIP) Screen
Pilot-Scale Impingement Survival Study.
Electric Power Research Institute. 2008. Net Environmental Effects of Retrofitting Power
Plants with Once-Through Cooling to Closed-Cycle Cooling, May 2008
Electric Power Research Institute. 2007. Fish Protection at Cooling Water Intakes: A
Technical Reference Manual.
Electric Power Research Institute. 1999. Fish Protection at Cooling Water Intakes: Status
Report. TR-114013. EPRI, Palo Alto, CA.
Fletcher, I. R. 1990. Flow Dynamics and Fish Recovery Experiments: Water Intake
Systems. Transactions of the American Fisheries Society 119: 393-415
Gathright, Trent (EEVICO). 2008. Email to John Sunda, SAIC. Re: Question about
Traveling screen mesh area and fish buckets. August 22, 2008.
Hadderingh, R.H. 1979. Fish Intake Mortality at Power Stations, the Problem and its
Remedy. N.V. Kema, Arnheem, Netherlands. HydrologicalBulletin 13(2-3):
83-93.
Pagano, R. and W.H.B. Smith. 1977. Recent Developments in Techniques to Protect
Aquatic Organisms at the Intakes Steam-Electric Power Plants. MITRE Technical
Report 7671. November 1977.
U.S. Environmental Protection Agency (EPA). 2002. Technical Development Document
for the Proposed Section 316(b) Phase II Existing Facilities Rule. EPA-R-02-003.
U.S. Environmental Protection Agency, Washington, DC.
Voutchkov, N. 2005. SWRO desalination process: on the beach - seawater intakes.
Filtration & Separation 42(8):24-27, October 2005.
White, J.C. and M.L. Brehmer. 1976. "Eighteen-Month Evaluation of the Ristroph
Traveling Fish Screens". In Third National Workshop on Entrainment and
Impingement. L.D. Jensen (Editor). Ecological Analysts, Inc., Melville, N.Y. 1976.
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Chapter 7: Regulatory Options
7.0 Introduction
This chapter briefly discusses the technology bases and regulatory options EPA considered
for proposed impingement and entrainment reduction controls. For a complete discussion,
refer to the preamble to the proposed rule.
7.1 Technology Basis Considered for the Proposed Regulation
After examining the technologies described in Chapter 6, EPA rejected all but three
technologies as BTA as they were the only technologies that consistently and predictably
reduced impingement mortality and entrainment mortality. These technologies are:
1) impingement mortality reductions based on modified Ristroph screens, 2) impingement
mortality reductions for shellfish based on barrier nets and 3) flow reduction in the form of
closed-cycle wet cooling towers.l The following section provides a discussion of these
technologies.
7.1.1 Modified Ristroph Screens
EPA's analysis identified modified Ristroph screens as the technology basis for
impingement mortality BTA requirements for all existing facilities.
As described in Chapter 6, traveling screens have been widely used at existing facilities for
decades. These screens were originally designed to prevent debris from entering the
cooling water system, but can also be used to prevent certain types offish and shellfish
from entering the system by similarly impinging them on the screen surface. Because fish
and shellfish are impinged on the screen, unless these screens are modified and also
accompanied by a system that allows for their return, or unless the through screen velocity
is reduced to 0.5 ft/sec or less and there is no entrapment of the fish, mortality associated
with impingement on traveling screens alone can be high. In an effort to reduce
impingement mortality associated with coarse mesh traveling screens, industry has
conducted various studies and implemented various modifications and additions to screen
design and operation including fish return.
The impingement mortality requirements considered are based on "modified traveling
screens." Modified traveling screens include all of the "Ristroph" and "Fletcher"
modifications including: smooth mesh; a low pressure wash spray designed and operated
for gentle removal of impinged organisms; and a bucket and/or lip design that maintains
adequate water to promote survival of impinged organisms.2 Modified traveling screens
also includes a fish handling and return system that is designed, maintained, and operated
:EPA earlier considered, but rejected, dry closed-cycle cooling towers as BTA at the national level. See 66
FR 65282 (Phase I), Chapter 4 of the Phase I TDD (DCN 3-0002), 69 FR 41608 (Phase II) and Appendix D of
the Phase II TDD (DCN 6-0004, EPA-OW-HQ-2002-0049-1459).
2 See Chapter 6 of the TDD and DCNs 10-6801, 10-6829, and 5-4387.
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to ensure adequate water to promote return of impinged organisms to the source water
body; minimized predation of the collected impinged organisms; and a discharge location
of the fish return that is sufficiently far from the cooling water intake to minimize
re-impingement. Throughout the supporting documents and associated docket, EPA's
reference to modified traveling screens assumes all of the aforementioned characteristics.
Any traveling screens (with or without fish returns) that do not incorporate all of these
characteristics are not considered BTA.
Unlike closed-cycle cooling towers and other flow reduction strategies, impingement
mortality reductions resulting from the application of modified traveling screens can vary
from site to site. While the effectiveness of modified traveling screens may vary from site
to site, data in the record demonstrate that their collective effectiveness approximates an
88 percent reduction in impingement mortality on an annual basis (that is, 88 percent of
impinged organisms survive).
Facilities may also comply with impingement mortality requirements by demonstrating
that they withdraw cooling water at an intake velocity that does not exceed 0.5 feet per
second. EPA's data still shows that over 94 percent offish can escape from 0.5 ft/sec
(burst swim speed), therefore reducing the intake velocity is protective of a large
percentage of impingeable organisms.4
7.1.2 Barrier Nets
The proposed impingement mortality requirements also require that facilities located on an
ocean or tidal river reduce the impingement of shellfish at locations where shellfish are
present; EPA's technical basis for this requirement is the addition of barrier nets to the
existing intake structure (and in addition to any traveling screen upgrades). Unlike fish,
some shellfish, in addition to being impinged on modified traveling screens due to intake
flows (similar to fish), may even attach to the screen itself (crabs may latch onto screens
panels and hold on while the panels rotate). During its site visits, EPA observed facilities
where shellfish (e.g., crabs) comprised a major portion of the impinged organisms.
Because of the larger physical size and irregular shape of most shellfish, barrier nets
prevent the shellfish from contacting the screen leading to large reductions in impingement
(and impingement mortality). As explained in Chapter 6, where facilities have installed
barrier nets, shellfish impingement can be reduced by as much as 98 percent (see DCN
10-6804).
7.1.3 Closed-cycle Cooling Towers
As explained in Chapter 6, there is a direct relationship between the quantity of water
withdrawn and impingement and entrainment. Available data demonstrate that
closed-cycle wet recirculating cooling systems (e.g., cooling towers or ponds) typically
3 The survival rate of 88% reflects a beta distribution with a 95% confidence interval. EPA also excluded
studies showing poorly performing screens from its data set. See Chapter 11 of the TDD for a complete
discussion.
4 See DCNs 2-028A-D, 2-029, and 2-030 in the Phase INODA docket. Additionally, the final Phase I rule,
the 2004 Phase II rule, and the Phase III rule all contained similar provisions regarding intake velocity.
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reduce mortality from impingement and entrainment by up to 97.5 percent when compared
with conventional once-through systems. Reducing the cooling water intake structure's
capacity is one of the most effective means of reducing entrainment (and impingement).
For the traditional steam electric utility industry, facilities located in freshwater areas that
have closed-cycle, recirculating cooling water systems can, depending on the quality of the
make-up water, reduce water use by up to 97.5 percent from the amount they would use if
they had once-through cooling water systems. Steam electric generating facilities that
have closed-cycle, recirculating cooling systems using salt or brackish water are somewhat
less efficient but still reduce water usage by up to 94.9 percent when make-up and
blowdown flows are minimized. EPA estimates that approximately one third of power
generation and manufacturing facilities currently have closed-cycle cooling. (See Chapter
4 for more information.) The effectiveness of closed-cycle cooling technology is widely
demonstrated and the number of existing facilities initiating retrofits to closed-cycle
cooling is increasing.5
7.2 Options Considered
After careful consideration of the technologies available, EPA developed four primary
options based on these technologies for today's proposed rule. Three of the options would
require the same impingement mortality standards, but would vary the approach to
entrainment mortality controls. The fourth option would allow both impingement and
entrainment mortality controls to be established on a site-specific BPJ basis for facilities
with a DIP less than 50 MGD. The options are described briefly below, followed by a
discussion of EPA's evaluation of each option as BTA. Also see the preamble for
additional discussion.
1. Option 1 - Uniform Impingement Mortality Controls at All Existing Facilities;
Site-Specific Entrainment Controls for Existing Facilities (other than New Units) that
Withdraw over 2 MGD DIP; Uniform Entrainment Controls for All New Units at Existing
Facilities
Under this option, all existing facilities withdrawing more than 2 MGD would be required
to meet either the design or the performance standard for impingement mortality.
Entrainment controls would be established by the permitting authority on a case-by-case
basis taking into account those factors at a particular facility. New units at an existing
facility that withdraws more than 2 MGD would have requirements similar to the
requirements of a new facility in Phase I. Under this option, new units would be required
to reduce flow commensurate with closed-cycle cooling for the new unit. Under the
proposal, as with Track II of the Phase I rule, a facility could demonstrate compliance with
entrainment control requirements by establishing reductions in entrainment mortality for
the new unit that are 90 percent of the reductions that would be achieved by closed-cycle
cooling.
5 For example, Dominion Energy's Bray ton Point Station is retrofitting to natural draft cooling towers to meet
NPDES permit requirements.
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2. Option 2 - Impingement Mortality Controls at All Existing Facilities that Withdraw
over 2 MGD DIP; Require Flow Reduction Commensurate with Closed-cycle Cooling By
Facilities Greater Than 125 MGD DIP and at New Units at Existing Facilities
Under Option 2, all in-scope existing facilities would be required to achieve the numeric
impingement mortality limits described in Option 1 above. In addition, this option would
require flow reduction commensurate with closed-cycle cooling by facilities greater than
125 MGD DIP and at new units. Option 2 explores using the facility size, in terms of
design intake flow (DIP), as a factor for establishing different BTA for different
subcategories. EPA's analysis shows that a DIF of 125 MGD would be an appropriate
threshold for this purpose. For all facilities that withdraw over 2 MGD but less than or
equal to 125 MGD DIF, entrainment controls would be determined by the permitting
authority on a case-by-case basis taking into account the factors at a particular facility.
Requirements for new units at an existing facility would be the same as described in
Option 1.
3. Option 3 - Establish Impingement Mortality Controls at All Existing Facilities that
Withdraw over 2 MGD DIF; Require Flow Reduction Commensurate with Closed-Cycle
Cooling at All Existing Facilities over 2 MGD DIF
Under this option, all in-scope existing facilities would be required to achieve numeric
impingement mortality limits as described in Option 1 above. In addition, this option
would require flow reduction commensurate with closed-cycle cooling by all facilities
(including new units at existing facilities) as described in Option 2. Requirements for new
units at an existing facility would be the same as described in Option 1.
4. Option 4 - Uniform Impingement Mortality Controls at Existing Facilities with Design
Intake Flow of 50 MGD or more; BPJ Permits for Existing Facilities with Design Intake
Flow Less Than 50 MGD; that Withdraw over 2 MGD DIF; Uniform Entrainment Controls
for All New Units at Existing Facilities
Under Option 4, only in-scope existing facilities with a design intake flow of 50 MGD or
more would be required to comply with uniform national impingement regulatory
requirements as described in Option 1 above. In-scope facilities with a design intake flow
less than 50 MGD would not be subject to the national impingement requirements in
today's proposed rule but would continue to have their 316(b) permit requirements
established on a case-by-case, best professional judgment basis. In the case of an existing
facility below 50 MGD that adds a new unit, the flow associated with the new unit would
be subject to the uniform entrainment requirements based on closed-cycle cooling.
Finally, all existing facilities withdrawing in excess of 2 MGD of design intake flow would
be subject to entrainment controls established on a site-specific basis.
Other Options Considered
In addition to the options discussed above and in the preamble, EPA also explored a
number of other options that it ultimately rejected. No national-level compliance costs for
these options are provided in Chapter 8; see Chapter 6 for unit-level costs. These options
are presented below.
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Other variations on the primary options: EPA evaluated numerous options that used the
same principles as the options above, with impingement mortality addressed by screens
and entrainment mortality based on closed-cycle cooling. Primarily, these options
examined flow thresholds other than 125 MGD. EPA also evaluated various cost scenarios
using the EPRI cooling tower cost tool, such as using "difficult" costs for all facilities.
Fine mesh screens: EPA evaluated an option where impingement mortality and
entrainment mortality would be addressed jointly by the use of fine mesh (0.5 or 2 mm)
screens. This analysis also included various design intake flow thresholds. As discussed in
Chapter 6, EPA believes that due to the need to significantly expand the size of the intake at
a large number of facilities, fine mesh screens are not an available and demonstrated
candidate BTA technology for national standards.
Partial closed-cycle cooling: EPA evaluated an option that would have required facilities
to install partial closed-cycle cooling; this option would achieve moderate levels of flow
reduction (as compared to fully closed-cycle systems) but at a lower cost.
Seasonal closed-cycle cooling: This option would have required facilities to install
closed-cycle cooling, but only operate the closed-cycle system during parts of the year that
correspond to the most biologically sensitive periods in the source waterbody. This option
would achieve moderate levels of flow reduction on an annualized basis but at a lower cost
(primarily due to reduced O&M costs over the life of the equipment).
Capacity utilization: EPA evaluated options that included a facility's capacity utilization
rate, including the 15 percent threshold used in the 2004 Phase II rule. These options
included requirements for closed-cycle cooling for facilities above 15 percent.
Waterbody type: EPA evaluated options that would establish different requirements for
facilities located on different waterbody types, including the approach used in the 2004
Phase II rule.
Water efficiency: EPA examined various approaches to assess a facility's water use
efficiency by comparing the volume of water withdrawn to the amount of electricity
produced.
Extended implementation: EPA evaluated an extended compliance timeline for several
options (especially those involving closed-cycle cooling) to mitigate concerns over grid
reliability and add flexibility. As part of Options 2 and 3, EPA would provide flexibility to
the Director to establish compliance timelines for each existing facility to mitigate grid
reliability and local electricity reliability. For example, the Director could schedule facility
compliance timelines to avoid multiple baseload facilities from being offline at the same
time. In some cases, additional time to comply would allow opportunity for transmission
system upgrades to further mitigate local reliability. Further, this would allow installation
outages (downtime) to be coordinated with each specific facility's maintenance schedule.
Under this option, most existing facilities would have no more than 10 years to complete
the retrofit to closed-cycle cooling. The Director would determine when and if any such
schedule for compliance is necessary, and if the facility is implementing closed-cycle as
soon as possible. This provision would give the Director the discretion to provide nuclear
facilities with up to 15 years to complete the retrofit, because all nuclear facilities are
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Chapter 7: Regulatory Options
§ 316(b) Existing Facilities Proposed Rule - TDD
baseload generating units and the additional flexibility in timelines would further mitigate
energy reliability, and because the retrofits at these types of facilities in particular involve
additional complexities and safety issues. The 15 years for nuclear facilities also provides
an opportunity to schedule the installation outage to coincide with safety inspections,
uprates, and other outages due to major facility modifications. Manufacturing facilities
could also receive up to 15 years to complete the retrofit to closed-cycle due to the
complexity of manufacturing facilities, multiple process units and product lines, and to
allow consideration of production schedules in setting such a timeline.6
Exhibits 7-1 and 7-2 show cumulative plots by design intake flow of costs, flow, and
facility counts.
Exhibit 7-1. Weighted Pre-Tax Compliance Costs ($2009) by DIF Threshold (MGD)
$7,000,000,000
_ $6,000,000,000
I
Si $5,000,000,000
V)
8
01
(J
$4,000,000,000
a. $3,000,000,000
J
8 $2,000,000,000
01
1_
Q.
$1,000,000,000
$0
0 500 1,000 1,500 2,000 2,500 3,000 3,500
DIF Threshold (MGD)
While EPA's analyses show that there would be no national problems with grid reliability, it is possible that
localized issues could arise if multiple plants in one area experience downtime simultaneously. For example,
during EPA's site visits to the Los Angeles and Chicago areas, facility representatives noted that extended
outages in those areas could be especially problematic given the limited transmission and generating
capabilities within those cities. By allowing an extended timeframe for compliance, facilities, parent
companies, and regulatory authorities could properly examine local and regional schedules to optimize when
a given facility would go offline. Nuclear facilities were permitted a longer timeline to account for additional
requirements due to NRC licensing and approvals, while manufacturers were allotted more time due to the
fact that they have less frequent extended outages for some operating units, making scheduling for
closed-cycle tie-ins more complicated.
7-6
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 7: Regulatory Options
Exhibit 7-2. Number of Facilities by Flow Threshold (MGD)
100%
80%
60%
40%
20%
0%
-Actual Intake
Flow (% of
national
withdrawals)
Facilities
above the
specified DIF
(% of all
existing
facilities)
500 1,000 1,500 2,000 2,500 3,000 3,500
Flow Threshold (MGD)
7.3 BTA Evaluation and Selection of Proposed Standards
EPA examined a range of technologies that reduce impingement and/ or entrainment, and
evaluated these technologies based on a number of factors. As described above,
closed-cycle cooling is the most effective technology for minimizing impingement
mortality and entrainment mortality. However, after considering all of the relevant factors,
EPA identified four factors that lead the Agency to conclude closed-cycle cooling is not the
"best technology available" for a uniform national entrainment mortality standard for all
facilities under Section 316(b). The four key factors for rejecting Options 2 and 3 in the
BTA determination are: local energy reliability, particulate emissions, land availability
inasmuch as it relates to the feasibility of entrainment technology, and remaining useful
plant life. See the preamble for additional details on EPA's process for selecting BTA.
7.4 Site-Specific Studies to Inform the Selection of Appropriate
Entrainment Controls
The proposed rule would require a site-specific determination of BTA. In that process, the
permit writer would have access to all the information necessary for an informed decision
about whether to adopt closed-cycle cooling or some other technology to reduce
entrainment mortality at facilities above 125 MGD AIF. Thus, the proposed rule requires
that the facility's permit application must include information to support such an
evaluation. (See the permit application requirements at 122.21(r) for more information.)
Following review of this information by the permit writer, the permit writer must
7-7
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Chapter 7: Regulatory Options § 316(b) Existing Facilities Proposed Rule - TDD
determine what BTA standard for entrainment reductions to adopt and explain in writing
the basis for that decision. The written explanation and the draft permit would then be
available for comment from the interested public under EPA's normal permitting program.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
Chapter 8: Costing Methodology
8.0 Introduction
This section describes the methodology and assumptions used to derive the technology
compliance costs for facilities required to meet the proposed rule. For existing facilities,
the Agency developed costs for 723 intakes at 519 model plants and these were then used
in the economic analysis to scale to the total universe of in-scope facilities. For new units
subject to entrainment mortality reduction requirements, the Agency derived estimates of
new unit capacity and cooling water requirements and derived estimated annual
compliance costs. In many ways, EPA used a similar, standardized approach to what was
used in the previous 316(b) rules. For regulatory options where facilities were required
to meet impingement mortality requirements (for which the technical basis is modified
Ristroph screens) or make intake technology upgrades, EPA used a revised version of the
cost tool developed in the Phase III regulation (and largely based on the cost modules
developed for the 2004 Phase II rule). For regulatory options where facilities were
required to meet entrainment mortality requirements (for which the technical basis is wet
cooling towers), EPA used a cost model developed by the Electric Power Research
Institute (EPRI) to develop costs for retrofitting wet cooling towers. EPA used facility-
specific data from each facility that completed a detailed technical questionnaire (DQ) to
create model facilities. By providing facility-specific data as an input to the cost models,
EPA determined compliance costs for each DQ facility or intake structure.
EPA diverged from the cost methodology in the 2004 Phase II rule in one key respect: the
costs derived for today's proposed rule use a model facility approach.l In contrast, the
2004 Phase II rule used a facility-specific costing approach where compliance costs
attributed to every facility were calculated. For reasons discussed below, EPA
determined that a model facility approach (where costs for a set of model facilities are
calculated and then scaled to a national level) was more appropriate in determining the
compliance costs for today's proposed rule. By costing each DQ facility as a model
facility, and by using the survey weights developed for the DQ,2 EPA is able to estimate
total national costs.
EPA also developed costs for manufacturers and small power plants (formerly addressed
under the Phase III rule), which are subject to the same requirements as large power
plants under today's proposed rule. The general process of developing costs for these
facilities was the same as that for large power plants, with some differences as discussed
below.
EPA analyzed the compliance costs on two levels. First, as described in Chapter 7, EPA
analyzed several regulatory options to address impingement mortality (EVI) and
1 Model facilities are statistical representations of existing facilities (or fractions of existing facilities); only
those facilities that completed a DQ in EPA's survey effort in 2000 were included in cost development.
2 The weighting factors were statistically derived from the industry questionnaire data using survey sample
sizes. Weights range from 1 to 8.7. By weighting each model facility, the traits of the model facility
(e.g., flow, technology type, capital costs) are extrapolated to represent the entire universe of facilities.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
entrainment mortality (EM), including intake screens and flow reduction commensurate
with closed-cycle cooling. Second, EPA assessed the national economic impacts of each
regulatory option. The sections below describe these costs further.
8.1 Compliance Costs Developed for the Proposed Rule
The proposed rule requires that all existing facilities must meet impingement mortality
requirements. Entrainment requirements for existing units may be established on a best
professional judgment basis by the Director. For new units not subject to Phase I, the
proposed rule requires intake flow reduction commensurate with closed-cycle cooling.
The cost methodology used to estimate compliance costs for new units is described in
Section 8.4 below. EPA also considered three other options involving closed-cycle
cooling: one where all existing facilities would be required to reduce their intake flow to
that commensurate with closed-cycle cooling; one where all existing facilities with an
average intake flow (AIF) above 125 million gallons per day (MGD) would be required
to reduce their intake flow to that commensurate with closed-cycle cooling, and one
where repowered/rebuilt existing units would be required to reduce their intake flow to
that commensurate with closed-cycle cooling. As described in the preamble to today's
rule, the technology basis for these requirements is jointly based on the performance of
modified Ristroph screens (for impingement mortality) and the performance of closed-
cycle wet cooling towers (for entrainment mortality).
To develop appropriate compliance costs, EPA assigned costs for both sets of facilities.
For facilities that are required to upgrade their screens, EPA used an updated version of
the cost tool developed in the Phase III rule. In addition, facilities with intakes on oceans
were assigned costs for seasonal deployment of barrier nets to reduce impingement of
shellfish. For the facilities that are required to reduce their intake flow, EPA used a cost
model developed by EPRI to develop capital and operation and maintenance (O&M)
costs for retrofitting cooling towers at each model facility.3
8.1.1 Model Facility Approach
The model facility approach used in this effort involved calculating compliance costs for
individual facilities for which EPA had detailed technical data regarding the intake design
and technology. Specifically, these are the in-scope facilities that completed the year
2000 DQ survey. For facilities with screen upgrades, where facilities reported data for
separate cooling water intake structures (CWISs), compliance costs were derived using
the design intake flow for each intake and then these intake costs were summed to obtain
total costs for each facility. For facilities required to reduce their flow, the EPRI model
was applied to the maximum intake flow reported for each intake over the period 1996 to
1998. The facility's total costs were then multiplied by a weighting factor specific to
each facility to obtain industry-wide costs for the national economic impacts analyses by
extrapolating the impacts of the DQ facilities to all existing facilities.
3 In some cases, a facility may have been assigned costs for both cooling towers and screen upgrades; if a
facility's characteristics suggested that, even after reducing flow, its intake velocity would still exceed 0.5
ft/sec, costs for Ristroph screens were also included. See section 5 below.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
The reasons for using a model facility approach include the following:
• Technical data for non-DQ facilities4 was limited; specifically:
o Design intake flow (DIP) volume was not requested, and values used
previously by EPA were estimated on the basis of reported average flow.
o Available intake technology data was generalized, and EPA could not be
certain how reported technologies were distributed among multiple intakes.
o Available intake technology data was not detailed enough to reliably ascertain
whether the technology design met compliance requirements.
• EPA's industry questionnaire conducted a census of power plants expected to be
within the scope of the regulations, but conducted a stratified sampling of
manufacturers. As a result, EPA's survey data only encompasses a representative
sample of manufacturers; information on unsurveyed facilities is not available.
• The survey sample frame did not include facilities in U.S. territories such as
Puerto Rico and Guam, and the model facility approach allowed their inclusion
using the weighting factors.
• Implementation of the 2004 Phase II rule revealed inconsistencies and errors in
the costs for non-DQ facilities.
8.2 Impingement Mortality Compliance Costs
Compliance with EVI requirements was based on the performance of an upgraded
traveling screen technology—a modified Ristroph-type traveling screen or equivalent,
plus a fish-friendly fish return system. Facilities may also comply with IM requirements
by demonstrating that their design intake velocity is 0.5 feet per second of less.
For both power generation and manufacturing facility intakes, EVI reduction compliance
technology costs were estimated on a per-intake basis using data from the model
facilities' DQs in the cost tool. Other input data were derived primarily from the
information used to develop the Phase II cost modules. As much as possible, EPA used
similar input data and cost calculation methodologies as were used in the 2004 Phase II
rule in developing the estimated compliance costs for assigned compliance technology
modules.
Using the model facility's input data, the cost tool assigns a compliance intake
technology to each facility (or intake). A detailed discussion of how the cost tool makes
technology assignments is provided below. EPA notes that the assigned technology for
each model facility intake in the proposed rule may be different than that assigned for the
2004 Phase II Rule, because EPA made a number of revisions to the cost tool.5 Through
4 Facilities were sent either a DQ or an abbreviated short technical questionnaire (STQ). The STQ
requested much less detailed information about the facility, its CWIS, and its operations. Of the
approximately 1,200 surveys that EPA sent to electric generators, approximately 62 percent were STQs.
All surveys sent to manufacturers were DQ surveys. For more information, see DCN 3-3077 (Statistical
Summary for the Cooling Water Intake Structure Surveys).
5 Revisions included adding more flexibility in assigning technology modules and revising some modules
to reflect EPA's proposed regulatory framework.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
the cost tool, EPA also accounts for any model facilities that have already installed
technologies that meet the performance requirements in the proposed rule.6 These
facilities are assigned no compliance costs.
The cost tool output includes capital costs, O&M costs, pilot study costs, and the duration
of facility downtime.
8.2.1 Selection of Technology to Address IM
Since the 2004 Phase II rule, EPA has revised and simplified the method for selecting EVI
reduction compliance technology. The EVI technology used for estimating compliance
cost was selected for each facility intake based on criteria such as existing through-screen
velocity, presence of traveling screens, intake location, water depth, and total intake flow.
A different technology selection decision tree was used for facilities with total intake
design flows in the 2-10 MOD range, due to the facts that: (1) survey data indicated that
fewer facilities in this flow range employed traveling screens as a baseline technology
and (2) the availability of wedgewire screens as a technology option was greater at lower-
flow intakes since the screens are smaller and site constraints such as water depth and
conflicts with navigation are less problematic.
Since the compliance standard is based on the performance of modified Ristroph
traveling screens, for the purpose of estimating compliance technology costs, EPA
limited the applied technology options to the following:
• Replacement of existing traveling screen(s) with coarse-mesh modified Ristroph
traveling screen(s) with fish return
• Installation of near-shore coarse-mesh wedgewire screen(s)
• Installation of larger intake with modified Ristroph traveling screen(s) with fish
return
• Installation of velocity cap(s)
• Installation of fish barrier net(s) in addition to traveling screen(s) in marine
environments.
The application of Ristroph screens is consistent with the levels of performance used to
calculate the performance standard for EVI. The other technologies (coarse mesh
wedgewire and velocity caps) were not included in the calculations for the performance
standard, but have shown that they are capable of consistently meeting the alternative
standard for intake velocity. Barrier nets are intended to address problems with the
impingement of shellfish.
6 For example, a facility might already employ closed-cycle cooling or a technology that EPA deemed
would meet the performance requirements. Some facilities also have unusually low intake flows and
achieve similar performance to closed-cycle cooling.
-------
§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
8.2.2 EPA's Cost Tool
For the Phase III rule, EPA developed a cost tool to model the general methodology used
in developing the compliance costs in the 2004 Phase II rule. For today's proposed rule,
this cost tool was further modified to mimic the 2004 Phase II rule cost methodology as
much as possible, as well as to increase its versatility. The modified cost tool used for
today's proposed rule costs each intake structure independently, which could result in
somewhat higher costs; facilities installing a technology at multiple intake structures
would likely realize some economies of scale or other cost reductions. The cost tool was
used to develop costs for both power plants and manufacturers.
The following modifications were made to the Phase III cost tool:
• The methodology for assigning compliance technology cost modules was
modified (see below for more details).
• A model input value for Selected Technology Module was added to allow the user
to specify which cost module(s) are applied.
• A model input value for Selected Engineering News-Record (ENR) Construction
Cost Index (CCI) was added to allow the user to adjust costs for inflation.
• A model input value for Regional Cost Factor was added to allow specific
regional cost factors to be used. Default values are average values for the state.
• Cost Modules 10, 10.1, and 10.2 were created to represent the costs for adding
fish barrier nets (Module 5) to Modules 2, 2a, and 3 (combinations of fine mesh
traveling screens and expanded intake structures). (See Exhibit 8-1 for a
description of each module.)
• The same waterbody-specific default distances offshore were applied for
relocating intakes to submerged offshore for all types of intake locations.
• The technology service life was added to the output.
• The input page was revised to allow selection of the Module 3 compliance screen
velocity.
• An existing impingement technology code was added for wedgewire screens.
• The cost modules for new larger intakes (Module 3) and wedgewire screens
(Modules 4, 7, and 9) were based on a design including fine mesh screens.
However, compliance with the EVI reduction technology requirements requires
only coarse mesh. As a result, Module 3 was modified so that the traveling
screens were sized based on a through-screen velocity of 1.0 fps and coarse
(3/8-in) mesh instead of fine mesh screens. The cost for wedgewire screens,
however, was not modified. Since smaller mesh sizes require larger screens due to
the lower percent open area, the associated capital costs for Modules 4, 7 and 9
represent a conservative overestimate. Module 1 (replacing existing screens with
modified Ristroph traveling screens and adding a fish return) always assumed use
of coarse mesh and did not change.
8-5
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
A very important modification of the cost tool was the change to the methodology for
selecting the compliance cost module for each model facility/intake. As noted above,
facilities/intakes determined to already be in compliance were assigned no compliance
technology costs. The methodology used to determine which facilities already met the
compliance requirements is described below. All model facility intake structures
determined to not be in compliance were assigned technology compliance modules as
described below.
Facilities with a design intake flow between 2 and 10 MGD were assigned technology
compliance modules using a slightly different decision process; in reviewing the
questionnaire data, EPA noted that many facilities in this group did not use traveling
screens. As a result, the technology choices these facilities would make are likely
different than a facility that has an existing traveling screen that it can modify. This
alternative process is also discussed below.
The addition of barrier nets to some technologies (e.g., Modules 10, 10.1, and 10.2)
involved simply calculating the sum of the individual component cost modules. Because
each cost module has a different O&M fixed factor, the fixed factor used in the combined
modules was calculated as a weighted average using the gross compliance O&M for each
component.
Exhibit 8-1 presents a decision flow chart that shows how the EVI compliance cost
modules were assigned to each facility/intake structure (with a DIP greater than 10
MGD) by the cost tool. Exhibit 8-2 shows the decision tree for facilities with a DIP
between 2 and 10 MGD. The subsequent text describes the decision points in the
flowchart (e.g., screen velocity) and other assumptions. Note that the second decision in
the top row assumes that a facility with a fish handling and return system is already
employing a traveling screen. Passive screens (e.g., cylindrical wedgewire screens) do
not have separate fish handling and return systems.
Capital and O&M Costs
The modified cost tool provides individual facility/intake cost values for capital costs,
fixed and variable O&M costs (baseline, gross, and net), estimated net construction
downtime, and technology service life. The cost tool provides an inflation cost
adjustment from the year 2002 dollars which were the basis for the 2004 Phase II rule.
The data presented are adjusted using the ENR CCI. Cost data presented are adjusted for
inflation using the February 2009 ENR CCI (8532.75).
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
Exhibit 8-1. Flow Chart for Assigning Cost Modules for Impingement Mortality
Reduction Requirements for Facilities with Design Intake Flow >10 MGD Based on
Meeting Performance of Modified Ristroph Traveling Screens
Existing Intake
Qualified for
Impingement
Mortality
Reduction?*
NO
YES
YES
Existing Screen
Velocity Less
Than 2.5 fps?
NO
YES
Existing
Shoreline
Intake?
NO
Waterbodv
Assigned Module
All
No Upgrade
Required
Waterbodv
Assigned Module
Ocean 10.3
Estuary/Tidal River 10.3
Great Lakes 1
Freshwater Streams 1
Lake/Reservoir 1
Is Water Depth
at Intake <20 ft
YES
NO
Waterbodv
Assigned Module
Ocean 10.2**
Estuary/Tidal River 10.2**
Great Lakes 3**
Freshwater Streams 3**
Lake/Reservoir 3**
Waterbodv
Assigned Module
Ocean 10.2**
Estuary/Tidal River 4
Great Lakes 4
Freshwater Streams 4
Lake/Reservoir 4
Cost Module Legend
*IM Qualifications Include:
- Modified Ristroph Type
Screen
- Velocity Cap (<0.5 fps)
- Wedgewire Screen
** Larger intakes are sized
using design screen velocity
of 1.0 fps and percent open
area for 9.5 mm screen
mesh (68%)
Module Technology Description
1 Add Fish Handling and Return System (includes screen replacement)
2 Add Fine Mesh Traveling Screens with Fish Handling and Return
2a Add Fine Mesh Overlay Screens Only
3 Add New Larger Intake Structure with Fish Handling and Return
4 Relocate Intake to Submerged Near-shore (20 M) with passive fine mesh screen (1.75 mm mesh)
5 Add Fish Barrier Net
6 Aquatic Fish Barrier (Gunderboom)
7 Relocate Intake to Submerged Offshore with passive screen (1.75 mm mesh)
8 Add Velocity Cap at Inlet
9 Add Passive Fine Mesh Screen (1.75 mm mesh) at Existing Inlet of Offshore Submerged
10 Module 2 plus Module 5
10.1 Module 2a plus Module 5
10.2 Module 3 plus Module 5
10.3 Module 1 plus Module 5
11 Add Double-Entry, Single-Exit with Fine Mesh, Handling and Return
12 Relocate Intake to Submerged Near-shore (20 M) with passive fine mesh screen (0.75 mm mesh)
13 Add 0.75 mm Passive Fine Mesh Screen at Existing Inlet of Offshore Submerged
14 Relocate Intake to Submerged Offshore with 0.75 mm passive screen
8-7
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Chapter 8: Costing Methodology
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 8-2. Flow Chart for Assigning Cost Modules for Impingement Mortality
Reduction Requirements for Facilities with Design Intake Flow 2-10 MGD Based on
Meeting Performance of Modified Ristroph Traveling Screens
Existing Intake
Qualified for ^S
Impingement
Mortality
Reduction?*
NO
i
Existin
Veloc
Than
NO
i
Exis
Shor
Inta
NO
i
YES
ig Screen
iry i^ess
2.5 fps?
ting YE8
eline
ke?
Waterbodv Assigned Module
All 8
No Up
* Requ
Traveling
Screen?
NO
grade
ired
Waterbodv
Assigned Module
Ocean 10.3
Estuary/Tidal River 10.3
Great Lakes 1
Freshwater Streams 1
Lake/Reservoir 1
Waterbodv
Ocean
Assigned Module
4
Estuary/Tidal River 4
Great Lakes 4
Freshwater Streams 4
Lake/Reservoir 3
C
E
C
F
L
)cean 10.2**
stuary/Tidal River 4
ireat Lakes 4
reshwater Streams 4
ake/Reservoir 3
Cost Module Legend
*IM Qualifications Include:
- Modified Ristroph Type
Screen
- Velocity Cap (<0.5 fps)
- Wedgewire Screen
** Larger intakes are sized
using design screen velocity
of 1.0 fps and percent open
area for 9.5 mm screen
mesh (68%)
Module Technology Description
1 Add Fish Handling and Return System (includes screen replacement)
2 Add Fine Mesh Traveling Screens with Fish Handling and Return
2a Add Fine Mesh Overlay Screens Only
3 Add New Larger Intake Structure with Fish Handling and Return
4 Relocate Intake to Submerged Near-shore (20 M) with passive fine mesh screen (1.75 mm mesh)
5 Add Fish Barrier Net
6 Aquatic Fish Barrier (Gunderboom)
7 Relocate Intake to Submerged Offshore with passive screen (1.75 mm mesh)
8 Add Velocity Cap at Inlet
9 Add Passive Fine Mesh Screen (1.75 mm mesh) at Existing Inlet of Offshore Submerged
10 Module 2 plus Module 5
10.1 Module 2a plus Module 5
10.2 Module 3 plus Module 5
10.3 Module 1 plus Module 5
11 Add Double-Entry, Single-Exit with Fine Mesh, Handling and Return
12 Relocate Intake to Submerged Near-shore (20 M) with passive fine mesh screen (0.75 mm mesh)
13 Add 0.75 mm Passive Fine Mesh Screen at Existing Inlet of Offshore Submerged
14 Relocate Intake to Submerged Offshore with 0.75 mm passive screen
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
Pilot Study Costs
Pilot study costs were estimated in a similar manner as was done for the 2004 Phase II
rule. Each technology is assigned a pilot study cost factor of either 0 or 0.1. The capital
cost is multiplied by the pilot study cost factor to derive the estimated pilot study cost for
the facility/intake.7 A minimum pilot study cost of $150,000 in 2002 dollars was
assigned if the calculated pilot study cost in 2002 dollars was lower than the minimum.
For facilities with multiple intakes assigned the same technology, it was assumed that a
pilot study would be performed at only one of the intakes and thus the highest individual
intake pilot study cost was assigned to the facility.
For the proposed rule, few facilities were assigned pilot study costs. As described above,
the process for assigning compliance technologies led many facilities to be projected to
install Ristroph screens. This is a well-developed technology and typically does not
require a pilot study. Facilities that were projected to install Cost Module 4 (relocate the
intake to an offshore location with a fine mesh passive screen) were assigned pilot study
costs, as this is a significant shift in operations and may be well-served by conducting a
pilot study.
Construction Downtime
Construction downtime estimates are based on the estimated total downtime defined for
each technology cost module in the 2004 Phase II Technical Development Document. It
is assumed that the construction downtime will be scheduled to coincide with the
normally scheduled facility maintenance downtime. Net downtime values are equal to
the total estimated downtime minus the estimated average duration of the normally
scheduled maintenance downtime period of 4 weeks.
The 2004 Phase II and Phase III downtime estimates generally focused on facilities with
large intake flows, with the Phase II estimates being for facilities with DIP >50 MGD.
For manufacturers, these values were then adjusted downward based on structural,
process, and operational differences but not necessarily size. Similarly, a design flow in
the 2 to 10 MGD range would tend to involve smaller structures with pipes in the 10-in to
22-in diameter range, rather than the 4-ft to 6-ft or more range for the larger systems.
Thus, the scope of these intake construction projects is much smaller and the duration of
each task should be correspondingly smaller as well. Accordingly, the net construction
downtime for wedgewire screens for design flows of 2 to 10 MGD was assumed to be 3
weeks based on BPJ. Exhibit 8-3 presents the downtime estimates used for the assigned
compliance technology cost modules.
7 Typically, facilities with calculated capital costs below $500,000 (in 2002 dollars) are not assigned pilot
study costs, because EPA assumes that facilities incurring smaller capital costs were unlikely to conduct a
pilot study.
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Chapter 8: Costing Methodology
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 8-3. Net Construction Downtime for Impingement Mortality Compliance
Technologies
Cost
Module
Number1
1
3
4
5
8
10.2
(3&5)
10.3
(1 &5)
Power Generators (Weeks)
Flow<
6,944
gpm
0
2
3
0
0
0
0
Flow
6,944 to
400,000
gpm
0
2
9
0
0
2
0
Flow
400,000
to
800,000
gpm
0
3
10
0
0
3
0
Flow>
800,000
gpm
0
4
11
0
0
4
0
Manufacturers (Weeks)
Flow<
6,944
gpm
0
0
3
0
0
0
0
Flow
6,944 to
400,000
gpm
0
0
7
0
0
0
0
Flow
400,000
to
800,000
gpm
0
1
8
0
0
1
0
Flow>
800,000
gpm
0
2
9
0
0
2
0
1See Exhibit 8-1 for key to module numbers.
8.2.3 Identifying Intakes That Are Already Compliant With
Impingement Mortality Requirements
Existing intakes that were considered to be IM compliant included those that:
o
• Employed modified Ristroph Traveling screens or equivalent with a fish return
• Had a through-screen or through-technology velocity of < 0.5 fps
• Employed velocity caps with an approach velocity of < 0.5 fps
• Employed wedgewire screens with a through-screen velocity of < 0.5 fps.9
Data from the 2000 DQ survey were used to determine intake compliance. Existing
intakes for systems that employed closed-cycle cooling were not assumed to be
EVI-compliant and thus were assigned EVI compliance technology costs unless the intake
technologies met the above criteria.10
8.2.4 Development of Cost Tool Input Data
This section describes the development of the data input file for calculating technology
upgrade compliance costs using the modified version of the Phase III cost tool. Where
available, the same data used to develop the compliance technology upgrade costs for the
8 Traveling screens were considered as equivalent to modified Ristroph if the survey reported use of a fish
return, fish buckets, and low pressure spray, regardless of whether they were specifically identified as
Ristroph in the survey.
9 If wedgewire screen velocity data was not reported, the wedgewire screens were assumed to be compliant;
EPA's experience has been that wedgewire screens are typically designed with a through-screen velocity of
0.5 fps.
10 EPA expects that many facilities with existing closed-cycle cooling systems (particularly wet cooling
towers) already meet the specified intake velocity threshold.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
2004 Phase II rule were used as the basis for this effort. It is important to note that, in the
2004 Phase II rule, separate costs were derived for different CWISs at the same facility
where such detailed data were reported. Such data was available for facilities that
completed the DQ surveys. The use of multiple CWISs for costing has been retained in
today's proposed rule. Therefore, for the DQ survey facilities, multiple intakes were
included in the cost data input list, and separate costs were derived for each intake
structure. For power generation facilities, separate cost estimates were derived for 406
intakes at 284 facilities. For manufacturers, separate cost estimates were derived for 317
intakes at 235 facilities.
Data Sources and Assumptions
Exhibit 8-4 below describes the source data and assumptions used in deriving the data
value for each cost tool input variable.u Data from the DQ surveys is generally denoted
as being derived from Question Qxx, which corresponds to the question on the survey
instrument.12 The assumptions and analysis of several inputs are more complex than the
others and are further discussed immediately following the table.
Exhibit 8-4. Input Data Sources and Assumptions
Input #
1
2
3
4
5
6
1
8
Description
Facility type
Cooling system type
State
Waterbody type
Fuel type
Capacity utilization percent
Input (intake) location
Distance offshore, ft
Assumptions/Discussion
All power generation facility/intakes are assigned Code 2 and
manufacturers are assigned Code 3.
Based on response to DQ question Q1d. Assigned Code 1 (Full
Recirculation) if the only items checked are recirculating cooling
systems. System consisting of recirculating ponds were assigned
Code 2. All else Code 0.
Data from Phase II and III Master.*
Data from Phase II and III Master. Data was compared to survey
data. Three facilities had portions of multiple intakes reassigned
due to different waterbody types for different intakes.
Data from 2004 Phase II costing and confirmed with survey
database. Primarily used to distinguish nuclear from non-nuclear
facilities. Field not applicable to manufacturers.
Steam Capacity Utilization Rate (CUR) from Phase II Master with
updates for facilities previously assigned CUR of 0 and with
missing values. Updates are based on year 1999 EIA data. Field
not applicable to manufacturers.
Coded using survey data. If multiple intake types were reported,
then assigned codes using the following hierarchy: Submerged
Offshore (Codes 4 or 5); Intake Canal; Embayment Bay, or Cove;
Shoreline Intake (Codes 1 or 6). Two facilities did not report
intake type and were assigned Shoreline Intake (Code 1).
Used survey data for DQ facilities with data in survey. Cost tool
will assign defaults on the basis of the waterbody type if the
survey value is zero or blank.
See DCN 10-6655A for a blank cost tool with the input page.
See http://water.epa.gov/lawsregs/lawsguidance/cwa/316b/index.cfm for blank copies of the surveys.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Input #
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Description
Canal length, ft
Waterbody use/ navigation
Mean intake depth, ft
Intake well depth, ft
Exceeds 5 percent mean
annual stream flow (1=Yes)
Design intake flow, gpm
New design intake flow, gpm
Average intake flow, gpm
Design screen velocity (fps)
Through-screen velocity flow
basis
Water type
(1=marine, 0=fresh)
Debris loading
(1=high, 0 = typical)
Impingement tech in-place
Qualified impingement?
Entrainmenttech in-place
Qualified entrainment?
Avg annual Generation
MWh (95-99)
Selected technology module
Assumptions/Discussion
Used survey data for DQ facilities with data in survey. Cost tool
will assign defaults on the basis of the waterbody type if the
survey value is zero or blank.
This field was not used for today's proposed rule.
Used data from 2004 Phase II Rule and Phase III Rule cost
development spreadsheets and survey data. Default value is 18
ft for power generators and 19 ft for manufacturers.
See detailed description below.
This field was not used for today's proposed rule.
DIP data taken from Phase II and III Master. For facilities with
multiple intakes, individual intake flow was obtained from survey
database. Confirmed that sum was equal to total in Phase II and
III Master.
Used to estimate costs for Modules 3, 4, 7, 12, and 14. Set equal
to maximum reported intake flow in DQ Question 25. Set equal to
reduced intake flow if Closed-cycle cooling technology is
applied.
Average Intake Flow (AIF) data taken from Phase II and III
Master. For facilities with multiple intakes, individual intake flow
was taken from survey database. Confirmed that sum was equal
to total in Phase II and III Master.
Values taken from 2004 Phase II Rule and Phase II Rule cost
development spreadsheet and survey data. Default value is 1.5
fps for power generators and 1.2 fps for manufacturers.
Survey requested design through-screen velocity. Therefore,
Code 1 (Existing Equipment Design Intake Flow) was assigned to
all.
Code assigned according to waterbody type. Assumed Ocean
and Estuary/Tidal River are marine. All others are fresh.
Values taken from 2004 Phase II and Phase III Rule costing.
Blanks in spreadsheet were not assigned codes.
See detailed description below.
See detailed description below.
This field was not used for today's proposed rule.
This field was not used for today's proposed rule.
This field was left blank.
This field is used for specifying a compliance module for which
costs are desired; if filled in, it will override the cost tool
technology assignment.
The Phase II and III Master files are confidential business information (CBI) files containing the most recent information
for data fields that have been revised, such as DIF or a facility's being subject to the rule. Other data fields (such as
intake location, facility state, and so on) are unlikely to change and are maintained in the original survey database.
Screen Well Depth (Input #12)
Compliance modules involving replacement or modifications of existing traveling
screens (including the baseline O&M costs) require a cost input value for the total height
of the traveling screens from the base to the deck, which is referred to as the screen well
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
depth. This data was not reported in the technical surveys and the previous estimates
were derived using the sum of the distances between top and bottom of the intake
opening and the mean water level, which was not necessarily a correct interpretation of
the data, especially for submerged intakes.
In this revised approach, EPA reviewed available screen well design data including data
from facilities that were visited. Waterbody type appeared to be an important factor,
since screen decks are generally situated at elevations that exceed expected extreme high
water levels and the degree of variation in water levels tends to be similar among similar
waterbody types. The data indicated that the difference between extreme high and mean
water levels tended to be greater for rivers and streams and lower for tidal applications.
Exhibit 8-5 presents the assumed distance from the mean water surface to the screen deck
that was derived from trends in the available data. The estimated screen well depth of
each traveling screen was derived by adding the distances shown in Exhibit 8-5 to the
mean intake water depth (Input #11). The resulting values in most cases resulted in
greater assumed well depths than those that were used to derive the previous compliance
cost estimates for the Phase II and Phase III Rules. This resulted in generally higher cost
estimates for cost modules involving replacement or upgrade of existing traveling screens
and for new larger intakes with traveling screens.
Exhibit 8-5. Assumed Height of Traveling Screen Deck
Above Mean Water Level.
Waterbody
Ocean
Estuaries/Tidal Rivers
Great Lakes
Rivers and Streams
Lakes/Reservoirs
Assumed Distance from Mean Water
Surface to Screen Deck (ft)
15
15
15
30
20
New Design Intake Flow (Input #15)
Depending on the selected compliance technology, the design flow used to estimate
compliance technology costs was either the design intake flow for each intake (DIP) or
the New Design Intake Flow. The New Design Intake Flow (NDIF) was set equal to the
maximum flow volume that was reported for the years 1996 through 1998 in question 25
of the detailed survey or the DIP if no detailed flow data were reported. This maximum
reported intake flow (MRTF) is assumed to be the maximum flow volume required for
cooling and other purposes. For most intakes, the MRTF is smaller than the DIF because
the reported DIF often included excess pump capacity that is either no longer needed or
serves as backup. When calculating intake technology costs for compliance options that
required closed-cycle cooling, the New Design Intake Flow was calculated by reducing
the DIF by 93 percent of the non-contact cooling flow volume used to estimate the
closed-cycle cooling system costs.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
The DIP was used to estimate IM compliance if the selected compliance technology
involved modification/replacement of the existing intake traveling screens (e.g., replace
existing traveling screens with modified Ristroph traveling screens). The NDIF was used
to estimate EVI compliance if the selected compliance technology could be sized
independently of the existing intake technology (e.g., wedgewire screens, velocity caps,
or a new intake).
In the current approach, the cost for Module 5 (barrier net) was developed as a separate
technology for each intake. In the 2004 Phase II rule, the barrier net costs were
developed using the combined flow of multiple intakes at the same facility. This is based
on the assumption that the multiple intakes are close enough together that they can be
protected by a single barrier net.
Impingement Technology In-place (Input # 21)
The following criteria were used to assign impingement technology codes:
• Assigned Code 1 (Traveling Screens) if answered Yes to Q19c Traveling Screen
Codes El, E2, E3, E4, E5, E6, F (Other) if description qualified.
• Assigned Code 5 (Wedgewire Screen) if answered Yes to Q21b Passive Intake
Code G.
• Assigned Code 2 (Passive Intake) if answered Yes to Q21b Passive Intake Codes
H, I, J, K.
• Assigned Code 3 (Barrier Net) if reported Fish Barrier Net Code P in Q22b.
• Assigned Code 4 (Fish Diversion or Avoidance System) if answered Yes to Q22
Fish Diversion or Avoidance System Codes M, N, O, Q, R, S, T, U, V.
Qualified Impingement? (Input # 22)
As described above, some intakes utilize technologies that were considered to already
meet the performance standard for impingement mortality. The following criteria were
used to make this assessment:
• Assigned Code 1 (qualified) if design screen velocity was< 0.5 fps.
• Assigned Code 1 (qualified) if survey indicated there was a combination of
technology components associated with a Ristroph-type, fish-friendly traveling
screen, including a separate fish return trough present. Included only intakes
answering Yes to Q20a (are screens used to reduce impingement and
entrainment?) and reporting several of the following:
o Q20b (I&E Reduction System-Spray Wash/Fish Spray);
o Q20b2 (I&E Reduction System-Fish/Debris Troughs);
o Q20b4 (I&E Reduction System-Fish Buckets/Baskets/Trays);
o Q23b Code W (Fish Pump);
o Q23b Code X (Fish Conveyance Systems);
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
o Q23b Code Y Fish Elevators/Lift Baskets);
o Q23b Code AA (Fish Holding Tank);
o Q23b Code BB (Other) provided description qualified.
• Assigned Code 1 (qualified) if there was a qualifying Fish Diversion or
Avoidance System intake technology reported in Q22b including:
o Code M (Velocity Cap); and
o The design intake velocity of the technology is 0.5 ft/sec or less.
• Assigned Code 1 (qualified) if there was a qualifying Passive Intake System
intake technology reported in Q 21b including:
o Code G (Wedgewire Screen); and
o The design intake velocity of the technology is 0.5 ft/sec or less.
If a technology applied to only a portion of parallel equipment (e.g., Ristroph screens on
only a portion of screens), it was assumed that the lesser qualified technology was present
on all equipment (i.e., the entire intake was designated as not qualified).
8.3 Entrainment Mortality Compliance Costs
To estimate costs of entrainment mortality (EM) controls using flow reduction, EPA
developed an option that would retrofit facilities with once-through cooling systems to
closed-cycle recirculating systems in the form of mechanical draft wet cooling towers.
Costs were derived for cooling systems associated with individual intakes.
In September 2007, EPA obtained an Excel spreadsheet from EPRI that contained a set of
calculations for estimating cooling tower retrofit costs at existing steam power plants.
EPA compared the EPRI model to the methodology used in the Phase IINODA and
found that the two methods produced similar costs. Because these methods produced
similar costs and the EPRI method was simpler and more flexible, the EPRI methodology
was chosen to develop the model facility cost equations for the proposed rule.
The EPRI methodology distinguishes between three separate capital cost values related to
the degree of difficulty associated with the cooling tower retrofit. The costs are
representative of an easy (lowest cost), average (intermediate cost) or difficult (highest
cost) retrofit. EPA derived model facility capital costs equations for both the average
and difficult retrofit scenarios for use in the applicable cost analyses.13 These different
levels of costs were applied differently to power generators and manufacturers.
13 EPA used the average scenario for the power generator compliance cost scenarios that include closed-
cycle cooling, because the costs were derived from power generation applications and are representative of
costs on a national scale (i.e., some facilities might face a difficult scenario, but others will have an easy
scenario, balancing costs on a national scale). For some IPM analyses, EPA used the difficult scenario
because it represented the highest cost scenario and would provide an indication of worst case economic
impacts. For more information, see the EEBA.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
EPRI lists the factors that affect the selection of the degree of difficulty rating for capital
costs as:
• Availability of tower space nearby
• Need to remove or demolish existing structures
• Whether the tower site elevation is higher than the existing cooling system intake
bay so cold water can flow by gravity to the intake bay
• Whether there are underground interferences in the path of the new circulating
water lines or at the location of the hot water sump and new circulating water
pumps
• Whether the tower site has overhead interferences, including transmission lines
• Whether the tower design might have to work around excluded areas where
activities that cannot not be moved or blocked occur (e.g., hazardous materials
storage, vehicle turn-around areas, and security areas)
• The degree of construction work needed to convert the existing intake to handle
the lower intake flow volume needed for make-up water
• How difficult it will be to tie the towers in to the existing cooling system
• Whether the site has unfavorable soil or geological conditions
• Whether the site has contamination that might require remediation
EPRI states that there is no simple way to determine how consideration of each of these
items will translate into assigning the project into the easy, average, or difficult
categories. If none of the items presents any obvious problems, an easy retrofit might be
expected. If two or three do, average is probably appropriate. If more than three, then
difficult is appropriate (DCN 10-6930).
EPA's costs for closed-cycle cooling include capital costs, O&M costs, energy penalty
losses, and downtime costs.14 EPA also included additional costs to account for noise
and plume abatement, which will be required at some sites. Cooling tower costs were
derived in a different manner than the intake technology costs (see below for more
information). In the case of the intake technology costs, technologies were assigned to
individual model facilities and the associated costs were calculated and scaled upward
(using survey weights) to determine the national model facility costs. For the cooling
tower costs, preliminary costs for individual DQ facilities were derived using the EPRI
spreadsheet and then aggregated to generate cost equations representing the national
average. The preliminary costs calculated for each intake using the EPRI calculation
worksheet were then adjusted using the regional cost factor derived for that plant in the
2004 Phase II rule.15 The model facility costs were then generated using these equations.
As in the case of the intake technology costs, the model facility cooling tower costs were
14 There are no pilot study costs for cooling towers (i.e., pilot study factor = 0). These technologies are
well studied, and the performance can be predicted using meteorological and other site specific data.
15 EPRFs cost methodology did not account for facility location. Construction costs do vary regionally, so
EPA applied the regional cost factor.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
then multiplied by a weighting factor specific to each facility to obtain national model
facility costs.
8.3.1 Capital Costs
Power Generators
Since the EPRI costs were derived from cooling tower retrofit costs for power generation
systems, it is reasonable to select the "average" difficulty costs as the basis for the
compliance costs for cooling towers for power generation cooling systems. It was
assumed that the recirculating flow rate of the cooling tower would be equal to the MRIF
of the existing cooling system. Intake-specific costs were derived for the facilities with
once-through cooling water systems that provided design flow data in the 2000 detailed
surveys. Facilities were included in this portion of the analysis regardless of the capacity
utilization rate (CUR), as this rate does not affect the DIP.
The ratio of capital cost to DIP (dollars/gpm) was then calculated for each plant. Various
methods for using this data to estimate costs were evaluated, including using cost curve
trend lines that varied with flow derived using Excel (which uses a least squares method)
and a linear approach using the between-facility average or median of the dollars/gpm
ratios. So as not to make assumptions that would lead to underestimating costs, EPA
assumed that a simple linear equation using the overall between-facility average of the
individual facility capital cost to DIP ratios (dollars/gpm) represented a reasonable
estimate for the national model facility costs.
EPA also evaluated whether applying the facility weighting factors to the calculation of
the average had any effect on the resulting average ratio of dollars/gpm and found that
the value changed by less than 1 percent. The same was true for the O&M cost
components as well.
EPA also recognizes that some generators are situated in locations that may require
plume and/or noise abatement. It is not clear from the EPRI tower calculation support
documentation whether the mix of retrofit projects from which the "average" difficulty
costs were derived are representative of the universe of facilities that would be required
to install closed-cycle cooling under the proposed rule. One concern is that the
compliance universe will include a larger proportion of facilities requiring additional
costs for requirements such as plume abatement, noise abatement, and space constraints.
EPA adopted a conservative approach to account for this possibility by modifying the
cost for closed-cycle cooling systems at power generators. An analysis determined that
approximately 25 percent of existing power generators may require additional costs
associated with plume and/or noise abatement and space constraints. Rather than attempt
to assign specific technology upgrade additional costs to specific facilities,16 EPA spread
these added costs throughout the entire universe of facilities that would be required to
16 EPA's concluded that the estimated costs of plume abatement was close to the capital cost of the EPRI
"difficult" scenario and should be representative of the cost of the mix of additional abatement
technologies.
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Chapter 8: Costing Methodology
§ 316(b) Existing Facilities Proposed Rule - TDD
undergo closed-cycle cooling retrofits since the existing plant database did not contain
sufficient detailed data to make a reliable determination regarding which specific
facilities would be subject to these requirements. These added costs were spread across
all facilities by adding the equivalent of 25 percent of the estimated additional costs for
plume abatement technology to the cost assessed for all facilities. The estimated
additional costs for plume abatement were considered as representative of the mix of
costs associated with plume abatement, noise abatement, and/or space constraints. (See
DCNs 10-6652 and 10-6653.)
Exhibit 8-6 presents the capital and O&M cooling tower cost formulas for the "average"
difficulty cooling tower retrofit. Exhibit 8-7 presents the adjusted "average" retrofit cost
factors modified to account for 25 percent plume abatement costs. The cost equations in
Exhibit 8-6 were also used to estimate compliance costs for manufacturers where non-
contact cooling water (NCCW) was used primarily for power generation purposes.1? The
cost equation factors in Exhibit 8-7 were used to estimate costs for power generating
facilities.
Exhibit 8-6. Cooling Tower Costs for Average Difficulty Retrofit
Costs and Generating Output Reduction
Capital Cost (CC)
Fixed O&M Cost (OMF)
Variable O&M - Chemicals (OMC)
Variable O&M - Pump & Fan Power (OMV)
Energy Penalty -Heat Rate (EP) Non-nuclear
Energy Penalty -Heat Rate (EP) Nuclear
Equation
CC = MRIF(gpm) x Constant
OMF = MRIF(gpm) x Constant
OMC= MRIF(gpm) x Constant
OMV= MRIF(gpm) x Constant
EP=MWSa x Constant
EP=MWS x Constant
Constant (2009)
$263
$1.27
$1.25
0.0000237
0.015
0.025
B MWS is the total steam generating capacity in MW.
Exhibit 8-7. Capital and O&M Cost Factors for Average Difficulty Cooling Tower
Retrofit with 25 percent Plume Abatement
Average Retrofit
Add for Plume Abatement
at a Single Facility
Average Increase if
Applied to 25 percent of
Facilities
Adjusted Constant
Capital Cost
(2009 Dollars)
Dollars/gpm
$263
$120
$30
$293
Fixed O&M
(2009 Dollars)
Dollars/gpm
$1.27
$1.00
$0.25
$1.52
Variable O&M -
Chemicals3
(2009 Dollars)
Dollars/gpm
$1.25
$0.00
$0.00
$1.25
Variable O&M -
Pump & Fan
Power
MW/gpm
0.0000237
0.0000031
0.0000008
0.0000245
a Non-power variable O&M costs are for additional treatment chemical for optimized tower operation at higher cycles of
concentration
17 The NCCW flow was considered as being primarily for power generation if the answer to question 4a
and 4b in the DQ survey indicated that >85 percent of the cooling water was used for power generation
purposes.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
Manufacturing Facilities
For manufacturing facilities, EPA recognizes that cooling tower retrofits will need to be
integrated into the existing manufacturing processes at different locations within the plant
and it is expected that in many instances difficulties will be encountered to a greater
degree and frequency than at power generators. Such difficulties may involve space
constraints, reconfiguration of process piping, long piping runs, conflicts with existing
piping and infrastructure, and utilities. These are some of the factors that EPRI cited as
contributing to a "difficult" designation for a cooling tower retrofit. In addition, the
cooling towers are likely to be installed as smaller units serving individual processes
throughout the plant, thus reducing the opportunity for savings from economies of scale
that may be achievable at power generators.
As a result of these considerations, EPA applied the "difficult" retrofit capital costs to any
closed-cycle cooling system retrofit at a manufacturer, with the exception of instances
where cooling water was used primarily for power generation purposes, as described
above. In such cases, the "average" difficulty costs shown in Exhibit 8-6 were applied.
Exhibit 8-8 presents the "difficult" retrofit cost equations utilized for estimating closed-
cycle cooling system costs for manufacturing facilities. Like power plants, the costs for
manufacturers are also based on the MRIF; however, as described below, manufacturers
have some key differences that were incorporated into determining the appropriate flow
for designing a cooling tower system.
Exhibit 8-8. Cooling Tower Costs for Difficult Retrofit
Costs and Generating Output Reduction
Capital Cost (CC)
Fixed O&M Cost (OMF)
Variable O&M - Chemicals (OMC)
Variable O&M - Pump & Fan Power (OMV)
Energy Penalty - Heat Rate (EP)
Non-nuclear
Energy Penalty - Heat Rate (EP) Nuclear
Equation
CC = MRIF(gpm) x Constant
OMF = MRIF(gpm) x Constant
OMC= MRIF(gpm) x Constant
OMV= MRIF(gpm) x Constant
EP=MWSa x Constant
EP=MWS x Constant
Constant (2009)
$411
$1.27
$1.25
0.0000237
0
0
Units
Dollars
Dollars
Dollars
MW
MW
MW
a MWS is the total steam generating capacity in MW.
Intake Flow Used To Estimate Costs
Aside from the difficulty of installation and retrofit, there is generally little difference in
the operation of cooling water intake structures and cooling systems between power
plants and manufacturers. Both types of facilities use cooling water in similar ways.
However, manufacturers have one fundamental difference—they tend to use more
process water and contact cooling water. In many cases, process water is withdrawn via
the same intake structure as cooling water, creating a more complicated water balance
diagram.18
Reuse of cooling water as process water also presents a regulatory challenge, as these flows are no longer
considered cooling water.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
Cooling water can consist of both non-contact cooling water (NCCW) and process
contact cooling water (CCW). Contact cooling water which comes into direct contact
with process chemicals and materials can pick up contaminants during the cooling
process and may require treatment to remove contaminants if it is to be recirculated
through a cooling tower and reused in the process. In some cases (e.g., certain steel-
making processes), the required treatment process may be minimal (e.g, settling), but in
others, flow reduction is not possible without materially affecting the facility's operations
or products since the water quality requirements for the contact cooling water may render
recirculation of CCW impractical since manufactured product quality and/or process
performance may suffer without costly treatment. For this reason, EPA did not consider
flow reduction using closed-cycle cooling as a readily available technology option for
CCW or combined flows that included CCW or process water that could not be
segregated. Therefore, closed-cycle cooling was only applied to the estimated NCCW
component of the intake flow for manufacturers.
As a result, EPA reviewed a number of flow balance diagrams from the DQ industry
questionnaires for facilities in multiple industrial sectors and developed an estimated
proportion of total intake flow that is dedicated to cooling.
At power generators, the majority of intake water is used as non-contact cooling water for
condensing steam and equipment cooling (service water). Only a small portion is used
for process water or contact cooling. Therefore, for cost estimation purposes, the NCCW
flow was assumed to be the entire intake flow. For power plants that provided intake
flow data in question 25 of the technical survey, the MRTF was used as the cooling tower
design flow. Otherwise, the DIP was used.
For manufacturing facilities, the proportion of intake water used for process, NCCW, and
CCW purposes varied widely between industry types and facilities within each industry.
In order to determine water use trends at manufacturers, EPA examined data reported in
the 2000 detailed technical surveys for the large flow facilities with DIP >100 MGD.
The detailed technical survey requested information concerning percent of cooling water
flow used for: 1) electric generation; 2) air conditioning; and 3) contact or non-contact
process cooling. Unfortunately the survey did not distinguish between contact and non-
contact process cooling water, so schematic flow diagrams were also examined since they
often contained additional data concerning flow volumes and specific water uses. All
available data concerning the following items from both the survey responses and the
schematic flow diagrams were then summarized in a database with the following
components:
• Plant ID
• Design intake flow (DIP)
• Maximum reported intake flow (MRTF)
• Average intake flow (AIF)
• Cooling system type
• Industry type
• Non-contact cooling flow (NCCW)
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
• Non-contact cooling flow used mostly for electricity generation
• Process and/or contact cooling flow
• Answer to survey question 4a or 4b (percent cooling water used for electricity
generation)
• Answer to survey question 3h (estimated percent of design capacity used for
cooling)
• Detailed notes
"Type of cooling water use" and "flow volume" data was available in only a portion of
the schematic diagrams. However, enough data was available to estimate NCCW flow
for four or more facilities that could be categorized into one of the following industrial
groups:
• Chemicals
• Paper
• Petroleum
• Metals
• Other
With NCCW flow data now available for this subset of facilities, a methodology was
derived to estimate NCCW flows for other facilities in the database. In order to simplify
the approach, it was assumed that the general mix of process water, NCCW, and CCW
use would be somewhat similar within each of these major industry groups.
The NCCW flow for each facility was then compared to available flow data representing
total flow. Three factors based on the total NCCW flow were then evaluated to see if
they would be suitable for estimating the NCCW component at facilities where detailed
data were not available. For each factor, the total NCCW flow value taken from the
schematic diagrams was divided by the total process and cooling flow from the diagrams,
the DIP and the MRIF. Facilities with low NCCW flow values that employed cooling
systems other than once-through or where the total flow (from the flow diagram in the
survey) was much lower than the AIF were not included in the analysis, since the NCCW
flow data for these facilities may not have included the volume of recirculating cooling
water. The remaining ratios were then averaged for all facilities with such data in each
industry group. Exhibit 8-9 presents the results of this analysis.
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Chapter 8: Costing Methodology
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 8-9. Ratio of Non-Contact Cooling Water Flow to Total Facility Flow for
Evaluated Manufacturing Facilities With DIF >100 MGD
Plant Type
Chemicals
Other
Paper
Petroleum
Metals
NCCW
/Diagram
Total (%)
80.2%
96.0%
77.6%
81.6%
83.8%
Number
with Data
5
5
3
4
7
NCCW
/MRIF (%)
70.5%
75.5%
64.0%
82.4%
46.3%
Number
with Data
2
3
1
3
2
NCCW
/DIF (%)
50.2%
65.4%
33.9%
31.6%
53.5%
Number
with Data
5
5
4
4
6
Value
Selected
for
Estimation
70.5%
75.5%
64.0%
82.4%
53.5%
As can be seen from Exhibit 8-9, the trend is for the ratio of "NCCW/Diagram Total" to
be greater than the ratio of "NCCW/MRIF" which is greater than the ratio of "NCCW/
DIF." EPA concluded that the ratios of "NCCW/Diagram Total" were less suitable for
extrapolating to other facilities since the values were on the high side and corresponding
diagram totals would not be available for the majority of facilities that were not
evaluated. The ratio of NCCW/DIF tended to be lower than the ratio of NCCW/MRIF
due to the fact that the MRIF was often lower, since the DIF often included intake
capacity that was seldom, if ever, actually utilized. Therefore, with the exception of the
metals category, the average ratio of NCCW/MRIF was selected as the factor to be used
in estimating NCCW flows using MRIF data. In the case of the metals category, the ratio
of NCCW/DIF was greater and was selected as the factor to be used in estimating NCCW
flows since it was the median of the three values and was based on a larger number of
data points.
The selected factors were then used to estimate the total NCCW flow for each
manufacturing facility in their respective categories by multiplying the factor times the
MRIF. In cases where MRIF data were not available, the DIF was used which may result
in some overestimation of the NCCW flow volume. For those facilities used to derive
these factors where actual NCCW data were derived from the flow schematics, the actual
NCCW value was used instead.
8.3.2 O&M Costs
The EPRI Tower Calculation Worksheet also produces a general O&M cost on the basis
of the facility's DIF. This cost is assumed to be a fixed O&M cost component consisting
primarily of labor and materials. The general fixed O&M cost was then adjusted using
the regional cost factor. Unlike the O&M costs calculated for intake technologies, the
O&M costs for the baseline intake technology were not deducted (except as noted below
under pumping height) for facilities converting to cooling towers. The use of a closed-
cycle cooling system will still require an intake system for make-up water. Although the
intake volume will be smaller, it will require O&M costs, which are assumed to be more
than offset by the existing intake O&M costs.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
The EPRI worksheet also generates an O&M cost associated with pump and fan energy
requirements. This is assumed to be a variable cost component that would vary with the
operation of the generating units. The value derived here is associated with generating
units operating at full capacity. Unlike the fixed O&M cost, this component was not
adjusted using the regional factor because it is expressed in units of power consumption,
which is not dependent on the facility's region.19
As with the capital costs, the fixed O&M to DIP ratio (dollars/gpm) and variable O&M to
DIP ratio (MW/gpm) were calculated. The Excel trend lines for the O&M costs and
power requirements were plotted against DIP, and average and median ratios of costs and
power requirements versus DIP were then compared. As with the capital costs, the
average of the facility ratios of fixed O&M to DIP (dollars/gpm) and variable O&M to
DIP (MW/gpm) represented reasonable estimates for the national model facility costs.
The EPRI worksheet contains numerous assumptions and default values that can be
modified using site-specific data. Specific relevant assumptions and default values are
listed below:
• Tower configuration was in-line rather than back-to-back, meaning towers are
oriented in single rows rather than rows of two towers side by side.
• AH1 (Elevation rise from sump level to pump level) was set at 0 ft.20
• AH2 (Elevation rise from pump to tower site) was set at 0 ft.
• AH3 (Height of tower hot water distribution deck) was set at 25 ft.
• Recirculating water pipe flow velocity was set at 8 fps.
• Tower loading rate was 10,000 gpm/cell
The EPRI cost worksheet also assumes that O&M costs are the same for cooling towers
with different retrofit difficulties. Thus, the same O&M costs were applied to all cooling
tower retrofits, regardless of the difficulty of the retrofit. EPA assumed the EPRI O&M
costs were based on current operating methods employed at power generators, which
often involved minimal use of chemical treatment and operation at lower cycles of
concentration. As described below, further adjustments to O&M costs were made for
plume abatement and for optimized operation with regards to flow reduction.
19 The EPRI worksheet can also derive pump and fan energy costs in dollars using heat rate and fuel cost
data, but this feature was not used. The input value for the national economic impacts analysis O&M pump
and fan energy component is the electric energy requirement in MW, not the cost in dollars. The MW
value derived from the equation represents the maximum energy requirement at full-capacity operation and
is expected to be reduced when the plant is operating at less than full capacity.
20 Although the default values of AH1 and AH2 were 5 ft and 10 ft, respectively (15 ft total), they were set
equal to 0 in EPA's cost estimates to offset a portion of the baseline once-through surface water intake
pumping energy requirement that would no longer be needed (i.e., the facility's intake structure will be
withdrawing less water and will require less energy; these savings were recouped by using different
assumptions for AH1 and AH2).
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
Plume Abatement Costs
Adjustments to O&M for cooling towers with plume abatement technology included an
increase in energy requirements and fixed O&M costs. The increase in energy
requirements was based on an assumed 8 ft increase in pumping head and a 10 percent
increase in fan energy to account for additional demands created by addition of the dry
section coils. The increase in the fixed O&M component was based on an assumed 80
percent increase in O&M costs for the additional maintenance associated with the dry
cooling section equipment. A more detailed discussion can be found in the "Cooling
Tower Noise Abatement and Plume Abatement Costs." (See DCN 10-6652.) These costs
are shown as the cost adjustment factors in Exhibit 8-7 above.
Optimization Costs
EPA found that current practice regarding chemical treatment of circulating water at
power generators mostly involved treatment with biocides such as chlorine, and that there
was often no incentive to optimize (reduce) makeup flows by operating at higher cycles
of concentration. Operating a closed-cycle cooling system at higher make-up and
blowdown volumes results in higher intake flow volumes and lower cycles of
concentration. Lower cycles of concentration generally reduce the need for careful
operational control and chemical treatment for scale formation or suspended solids
deposition. EPA assumed that compliance with the regulatory options for flow reduction
would include the operation of closed-cycle systems in an optimized manner, which may
include operating at higher cycles of concentration.21
To account for this, EPA increased the O&M cost estimates derived from the EPRI
model by adding another variable cost component to cover increased use of chemical
treatment. This component included additional costs for both increased chemical
treatment and added labor (See "Water Balance, Flow Reduction, and Optimization of
Recirculating Wet Cooling Towers," DCN 10-6673). Capital costs were not adjusted,
since the estimated cost of flow monitoring and chemical feed systems was very small—
equal to about 0.2 percent of the "average" difficulty retrofit cost. These costs are shown
as the chemical treatment cost component equations and factors in Exhibits 8-6 and 8-8
above.
8.3.3 Energy Penalty
The term "energy penalty" as associated with conversion to closed-cycle cooling has two
components. One is the extra power required to operate cooling tower fans and
additional pumping requirements, referred to as the parasitic energy penalty. The other is
the lost power output due to the reduction in steam turbine efficiency due to an increase
in cooling water temperature, referred to as the turbine efficiency penalty.
21 As noted in the preamble, EPA assumed 3.0 and 1.5 cycles of concentration for fresh and marine waters,
respectively.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
Parasitic Loss
The parasitic fan and pump energy penalty is included as a separate component in the
O&M costs described above and was applied in all cases. The parasitic penalty was
estimated as MW of power required, which was then converted to costs in the economic
model.
Turbine Efficiency Loss
The energy penalty associated with turbine efficiency loss due to the conversion from
once-through to recirculating cooling towers is best expressed as a percentage of power
generation.22 To offset the efficiency loss, a facility can increase its fuel consumption if
the steam boilers are operating below full capacity or it could experience a reduction in
electricity generated if the steam boilers are operating at full capacity and are unable to
increase steam output.
The turbine efficiency penalty is typically expressed as a percentage of power output. In
the Phase I Rule, EPA estimated an annual average energy penalty of 1.7 percent for
nuclear and fossil-fuel plants and 0.4 percent for combined cycle plants. The estimated
maximum summer penalty was 1.9 percent. The EPRI supporting documentation (DCN
10-6930) estimates the energy penalty to range between 1.5 percent and 2.0 percent, and
the EPRI cost model uses 2.0 percent as the built-in default.
9^
To reflect the differences in steam pressure for facilities using different fuels, EPA
distinguished between nuclear and fossil plants. Fossil plants experience a lower turbine
efficiency loss due to the higher system pressures, while nuclear plants would realize a
higher efficiency loss. As a result, EPA selected a turbine efficiency loss value of 1.5
percent for fossil plants and 2.5 percent for nuclear facilities, which is consistent with the
default value of 2.0. This value applies directly to the generation rate of the steam
generating units, and thus the cost will vary with the amount of electricity being
generated. (See "Cooling Tower Energy Penalties" [DCN 10-6670] for a more detailed
discussion).
For closed-cycle cooling retrofits at manufacturing facilities or intakes that do not
primarily generate electricity, no turbine efficiency energy penalty was assigned since no
power is being generated. For manufacturing power generation systems, the energy
penalty for turbine efficiency loss for non-nuclear power plants (i.e., 1.5 percent) was
applied.
22 Typically, cooling towers do not cool the circulating water to the same temperature as surface water used
in once-through cooling. As a result, the steam is not cooled as effectively leading to a higher steam
turbine backpressure and a loss of generating efficiency.
23 Steam turbines at nuclear facilities tend to operate at lower steam temperatures and pressures; therefore
the energy penalty associated with turbine efficiency is expected to be higher for nuclear power facilities
than for fossil-fuel facilities.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
8.3.4 Construction Downtime
Power Generators
In addition to the costs described above, a facility might also incur downtime costs. The
duration or cost of the construction downtime is not estimated by the EPRI worksheet. In
the Phase II NOD A, EPA assumed net construction downtimes of 4 weeks for non-
nuclear plants and 7 months for nuclear plants. These net values assume that the
construction tie-in would be scheduled to coincide with the plant's routine scheduled
maintenance event. Thus, the net value includes a deduction of the estimated
maintenance downtime period (4 weeks for non-nuclear facilities) from the total
estimated downtime. EPA asked for comments in the Phase IINODA regarding these
assumptions but then did not make any conclusions regarding the comments because the
cooling tower option was not included as part of the basis for the 2004 final rule.
While most comments stated that site-specific analyses would be required for downtime
estimates, one commenter (DCN 6-5049A, Comment ID 316bEFR.303.010) did cite an
estimate that each generating unit at Brayton Point (a non-nuclear facility) would require
7 months' downtime in addition to scheduled maintenance. However, this was a
projection based on information at the time. Since then, Dominion Energy purchased
Brayton Point and agreed to retrofit natural draft cooling towers. Construction is
currently underway and construction schedules indicate that tie-in for each unit will
require approximately one month.
Riverkeeper (DCN 6-5049A, Comment ID 316bEFR.332.001) argued that the 7-month
period for nuclear plants was too long and that the extended duration for the Palisades
plant included additional activities not associated with the cooling tower retrofit. EPA
responded to Riverkeeper's comments by suggesting that the 7-month period might be on
the low side because it is based on historical refueling duration of 2 to 3 months, which
has recently dropped to 30 to 40 days. These offsetting arguments support a decision to
retain the 7-month net downtime for nuclear power plants.
Another commenter (DCN 6-5049A, Comment ID 316bEFR.041.023) stated,
[I]nquiries made by [the Edison Electric Institute (EEI)] to engineering
experts with extensive experience in this field suggest that, for a fairly
simple retrofit, two months would be a more reasonable estimate, while
for more complicated situations three to four month outages would be the
minimum expected.
Besides the type of plant, another factor investigated for consideration in estimating
construction downtime was CUR. Presumably facilities with low CUR values would
have greater opportunity to schedule cooling tower tie-in construction activities such that
they coincide with downtime periods of greater duration than the 4-week scheduled
maintenance period assumed in the 2004 Phase II rule. A review of monthly flow data
reported in the surveys for a sample of facilities with year 2000 CUR values in the 15
percent to 30 percent range was conducted. The data indicated that the cooling water
systems at most of these facilities operated at least a portion of every month during each
of the three years reported in the survey (1996, 1997, 1998). Thus, there did not appear
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
to be additional scheduled downtime available for these facilities, so CUR was not
considered further.
In the 2004 Phase II rule, EPA assumed that most power plants schedule periodic
maintenance outages with an average duration of 4 weeks. As a result, the net lost
generation downtime for economic estimation was assumed to be the estimated
construction downtime minus 4 weeks.
While Hunton & Williams gives a range of 2 to 4 months depending on difficulty, EPA
has examples of retrofit tie-ins of even shorter duration from its site visits, ranging from
83 hours at Jefferies Station (South Carolina) to 30 days for each unit at Canadys Station
(SC). Given this range of from less than 1 up to 4 months (or longer for a few
exceptions) depending on the difficulty, the original assumption of 2 months total for
non-nuclear plants appears reasonable. Thus, the assumed net downtime for non-nuclear
power plants remains 4 weeks. Exhibit 8-10 below summarizes the net downtime
estimates.
Exhibit 8-10. Net Construction Downtime
Fuel type
Nuclear
Non-nuclear
Net Downtime
(Weeks)
28
4
Manufacturers
Downtime for manufacturers was assumed to be less than downtime for electric
generators, as manufacturers are often more segmented in their production and use of
cooling water and are more likely to be able to shut down individual intakes or process
lines without interrupting the production of the entire facility.
Given that the Phase III rule did not consider regulatory options requiring closed-cycle
cooling, EPA has not previously developed estimates for downtime at manufacturers for
cooling tower retrofits. For today's proposed rule, EPA is assuming that manufacturers
will experience no downtime for these retrofits in excess of maintenance downtime that
may already occur.
EPA recognizes that some manufacturers or individual process lines/units may operate
100 percent of the time and scheduled outages for maintenance on these units is rare and
may be several years between outages.24 However, EPA also recognizes that most
manufacturing facilities or individual lines/units do not operate under these conditions
and would be able to schedule downtime for a tie-in for a closed-cycle cooling system.
Additionally, some facilities may be able to take advantage of stored or stockpiled raw
materials (to avoid a bottleneck created by the offline unit) or may purchase or transfer
these intermediate materials from other vendors or parts of their facility. As a result, for
24 See EPA's site visit reports for manufacturing facilities.
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§ 316(b) Existing Facilities Proposed Rule - TDD
a national-scale assumption, EPA determined that zero downtime was a reasonable
assumption for manufacturers.
8.3.5 Identifying Intakes That Are Already Compliant With
Entrainment Mortality Requirements
Existing intakes that were considered to be EM compliant included those that:
• Reported using a closed-cycle cooling system using towers only (i.e., not in
conjunction with any other type of cooling system)
Data from the 2000 detailed technical survey were used to determine intake compliance.
Existing intakes for systems that employed closed-cycle cooling were not assumed to be
IM-compliant and thus were assigned IM compliance technology costs unless the intake
technologies also met the criteria for IM compliance.
Combination Cooling Systems
Intakes for cooling systems that reported using a combination of cooling system types
(e.g., one intake is used to supply a once-through unit and a closed-cycle unit) were
treated as if all cooling water flow was once-through. Intakes that reported closed-cycle
cooling systems using ponds were also treated as if all cooling water flow was once-
through. This was done because there was insufficient data available to determine which
portion of the intake water was used for once-through and which as make-up for existing
closed-cycle cooling, or whether the cooling pond operation represented closed-cycle
cooling. This approach is expected to produce conservative cost estimates for these
mixed cooling system facilities, since a portion of the flow may be make-up water and
not amenable to application of closed-cycle cooling technology.
Exhibit 8-11 below summarizes the number of facilities and intakes that were determined
to supply cooling water to closed-cycle cooling systems
Exhibit 8-11. Number of Model Facilities/CWISs Classified as Closed-Cycle
Intakes with full or partial once-
through in-place
Intakes with pond cooling system
Intakes with full closed-cycle
recirculation in-place
Facilities with both full closed-
cycle and full once-through
intakes
Total facilities or intakes
Electric Generators
Number of
Model Facilities
221
12
51
7
284
Number of
Model Intakes
with Separate
Cost Data
319
26
61
8*
406
Manufacturers
Number of
Model
Facilities
186
7
42
0
235
Number of
Model Intakes
with Separate
Cost Data
267
7
43
0
317
Number of closed-cycle intakes.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
8.4 Entrainment Mortality Compliance Costs for New Units
Power generation and manufacturing units that meet the definition of a "new unit" will be
required to meet EM reduction requirements. Closed-cycle cooling or an equivalent
reduction in entrainment for the cooling water component of the intake flow based on the
average intake flow (AIF) will be required for new units. The estimates for compliance
costs for such new units should be based on the net difference in costs between what
cooling system technologies would have been built under the current regulatory structure
and what will be built given the change in requirements imposed by the Proposed
Regulation. Compliance costs are derived using estimates of the new generating capacity
that will be subject to the requirement.
EPA expects that for Manufacturers, compliance costs associated with new units will be
negligible. A discussion of the rationale is provided in Section 8.4.2 below. The
following section describes cost development for the new unit provision for Electric
Generators only.
8.4.1 Compliance Costs for New Power Generation Units
New generating capacity at existing facilities can result from new units added adjacent to
existing units, repowering/replacement and major upgrades of existing units, and minor
increases in system efficiency and output. While a small portion of this new capacity
may result from minor improvements in plant efficiency and output, this analysis
assumes all new capacity will be associated with new units, repowered units, or major
unit rebuild/upgrades.
In the cost analysis, EPA considered separately two categories of new unit that are
covered by this provision:
1. New generating units
2. Repowered existing units
New Generating Unit Costs
New generating units will be constructed at either "greenfield" facilities subject to the
Phase I Regulation or at existing facilities where they may be subject to the new unit
requirements for entrainment reduction. The scope of new unit activity was estimated
using estimates of new power generation capacity by fuel/plant type derived from IPM
modeling. For the new unit costs analysis, EPA focused on coal, combined cycle, and
nuclear since these comprise the majority of increased capacity that utilize a steam cycle
and are most likely to be constructed at existing generation facilities.
EPA used the analysis performed for Phase I as the basis for determining what portion of
new capacity would be subject to this regulation. In the Phase I analysis, EPA
determined that 76 percent of new coal and 88 percent of new combined cycle capacity
would be constructed at new "greenfield" facilities and would be subject to Phase I, while
the remainder (24 percent of coal and 12 percent of combined cycle) would be
constructed at existing facilities and be subject to existing facility regulations. Using this
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as the basis, EPA has selected a value of 30 percent for both coal and combined cycle to
serve as a conservative (high side) estimate for the portion of new capacity that would be
constructed at existing facilities.
At existing nuclear facilities, only new capacity associated with construction of new
generating units will be subject to the new unit requirements. Because of their
considerable size and heat discharge, it is assumed that any new nuclear units will be
required by the permitting authorities to utilize closed-cycle cooling and so the capacity
for new nuclear units has not been estimated. Exhibit 8-12 presents a summary of new
capacity estimates.
Exhibit 8-12. Estimated Annual New Capacity Subject to New Unit Requirements
Fuel Type
Coal
Combined Cycle
Projected Annual
Average New
Capacity (MW)a
3,573
1,491
Estimated New
Capacity Subject to
Phase I
2,501
1,044
New Capacity Subject
to Existing Facility
Rule Requirements
(MW)
1,072
447
New nuclear capacity is assumed to use closed-cycle and was not estimated.
a Based on IPM projections for coal and combined cycle.
Baseline Compliance
New units will either use once-through, closed-cycle, or dry cooling systems25. For the
baseline condition, an estimate is needed for the occurrence of each type of system that
would have been utilized if there were no change in the regulatory requirements for new
units. The occurrence of each type in existing cooling systems can serve as a guide since
both new and replaced units will, at a minimum, use a similar technology. In some cases,
more effective technology may be required. About 32 percent of existing facility steam
generating capacity already employs closed-cycle and another 11 percent employs a
combination including closed-cycle for at least part of the plant. It is reasonable to
assume that, at existing plants where closed-cycle cooling is already employed for at least
part of the generating capacity, closed-cycle would be required for any new or repowered
capacity. Thus, based on current practice, at least 43 percent of new capacity is estimated
to be compliant in the baseline.
While permitting authorities are not required to impose closed-cycle cooling
requirements on new units that do not strictly meet the definition of a new facility under
Phase I, EPA notes that a number of NPDES regulatory authorities have been pursuing
closed-cycle cooling requirements for a number of existing facilities (e.g., New York,
California). EPA expects this to be particularly true where the new unit would result in a
substantial increase in the volume of once-through cooling water withdrawn above what
is currently permitted. Thus, an assumption that baseline compliance would comprise at
least 50 percent of new units at existing facilities appears to be a reasonable and possibly
conservative (low side) estimate. At the same time, it is assumed that in many cases,
25 Dry cooling is generally used in only a small portion of facilities in locations where water resources are
limited. Estimates of closed cycle cooling are assumed to include dry cooling.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
baseline repowered units will be allowed to continue to withdraw once-through cooling
water at current flow volumes and discharge heat at current rates even though units at the
plant may be completely reconstructed.
Repowering Versus New Units
The increased capacity at existing facilities is divided into two types of projects. The first
is new unit(s) added adjacent to the existing generating units, which would require a new
intake or the existing intake to be substantially modified to meet once-through cooling
water requirements. The second is a repowered unit which replaces existing generating
unit(s) and is assumed to be sized such that the existing once-through cooling water
intake volume will provide sufficient flow to meet heat discharge requirements. The
estimation of the distribution of new unit capacity between these categories is based on
earlier (2007) IPM projections, since more recent projections do not include this
distinction.
For combined cycle, approximately 88 percent of projected total new combined capacity
was estimated to consist of repowered oil and gas units. Based on this, EPA chose a
slightly lower value of 85 percent. The estimate for repowered coal capacity was very
small (<1 percent). However, since there are significant economic advantages to
repowering, EPA believes this value to be an underestimate and selected a value of 10
percent based on BPJ.
Exhibits 8-14 and 8-15 present the distribution of the estimated new capacity estimates
across each cost category for coal and combined cycle, respectively. Exhibit 8-13
presents the capacity values in Exhibit 8-12 that are assumed to be compliant in the
baseline or that require costs associated with closed-cycle cooling for new units. Only
the capacity increase shown in the far right-hand column was used to derive the costs for
new units. The capacity increase for existing units does not include existing capacity that
is replaced and, therefore, a separate approach was used for the compliance options
considered for repowered existing units and their associated compliance costs.
Exhibit 8-13. New Capacity Subject to New Unit Requirement by Cost Category
Fuel Type
Coal
Combined
Cycle
New Capacity
Subject to
Existing Facility
Rule
Requirements
(MW)a
1,072
447
New
Capacity
Compliant in
Baseline
(MW)b
536
224
New Capacity
Subject to New
Unit Compliance
Costs (MW)
536
224
Capacity
Increase for
Existing
Units (MW)
54
190
Capacity
Increase for
New Units
(MW)
482
34
New nuclear capacity is assumed to use closed-cycle and was not estimated.
a Values are from Exhibit 8-12.
b Facilities will install entrainment reduction technology independent of Rule requirements.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 8-14. Cost Category Distribution of New Coal Capacity
I Subject to Phase I • Compliant in Baseline
Increase for Existing Units • New Added Units with Costs
2%
Exhibit 8-15. Cost Category Distribution of New Combined Cycle Capacity
I Subject to Phase I • Compliant in Baseline
Increase for Existing Units • New Added Units with Costs
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
Compliance Cost Estimation
Compliance costs were considered for new units and for existing capacity that is
repowered. EPA investigated closed-cycle compliance costs for repowered units for
consideration under different compliance options, but did not include this option in the
proposed rule. Different approaches were used for estimating costs for new unit capacity
versus repowering of existing capacity. For new unit capacity, costs are derived using the
new unit capacity in MW as the input variable. For the repowering of existing capacity,
EPA estimated the annual average occurrence of repowerings26 as a percent of the total
number of generating units present in the 316(b) universe analyzed at the earlier stages of
rule development. Compliance costs for this repowered capacity are developed using this
factor applied to the corresponding current design intake flow volume.
Compliance costs for new units use the EPA estimates for retrofitting a closed-cycle
cooling system at existing facilities as the starting point. EPA developed the existing
facility retrofit costs using existing flow data and cost equations that used cooling flow in
gpm as the basis. The cost equations for new units are instead based on capacity in MW,
with costs derived using assumed cooling water requirements in gpm/MW. These
cooling water requirements assume that the typical existing plant design includes a once-
through cooling system with a condenser temperature rise (AT) of 15 °F, and that the
closed-cycle cooling system that replaces a once-though system will be optimized using a
AT of 20 °F. The cooling water flow estimates are based on a AT of 20 °F and plant
efficiency values of 42 percent for coal (which is the average of values for super-critical
and ultra-critical steam), 57 percent for combined cycle, and 33.5 percent for nuclear.
Capital Costs
EPA has found that the total estimated capital costs for a once-through cooling system
including a new intake are comparable to the capital costs of a closed-cycle cooling
system. Therefore, the compliance capital costs are assumed to be $0 for new added
units.
For repowered units, the existing once-through intake and pump system can be utilized
and so capital costs should more closely resemble existing facility closed-cycle retrofit
costs. However, since the repowering construction activities can still be quite extensive,
the full costs for an existing facility retrofit are not assessed because they include extra
costs for working around existing equipment and structures. For example, the retrofits
often include installing a separate pumping system for the cooling tower in addition to the
existing recirculating pumps, while a repowered unit can be designed to use one set of
pumps as is often the case in new construction. In addition, much of the higher costs
associated with the "average" and "difficult" retrofit scenarios will be avoided. Thus, a
cost value midway between an "easy" difficulty retrofit and the cost of a cooling tower
alone was chosen. The capital costs include adjustments associated with the assumption
that 25 percent of facilities will require plume abatement. EPA has estimated that the
26 EPA estimated that approximately 0.2 percent of existing capacity will be repowered each year and
applied this factor equally across all three fuel type. See Section 3 of the "Economic and Benefits Analysis
for Proposed 316(b) Existing Facilities Rule" for more details.
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§ 316(b) Existing Facilities Proposed Rule - TDD
cost of the cooling tower alone would be $80/gpm (See "Cooling Tower Noise, Plume
and Drift Abatement Costs" [DCN 10-6652]).
O&M Costs
The same O&M costs are used for both new added units and repowered units. These
O&M costs include costs associated with the assumption that 25 percent of facilities will
require plume abatement. Fixed and variable O&M costs are adjusted by deducting the
O&M costs estimated for the traveling screens that would have been used in the baseline
once-through system. The baseline O&M cost estimate is based on the cost tool output
for gross O&M for once-through traveling screens (Cost Module 1) using design input
values of: DIP = 132,500 gpm, screen velocity = 0.5 fps; well depth = 25 ft; freshwater.
The resulting gross O&M cost was equivalent to $1.6/gpm, which was then reduced by
10 percent to account for the new makeup system O&M and then divided into fixed and
variable components using a fixed factor of 0.4.
Energy costs are also adjusted to account for the reduced pumping volume associated
with changing the AT from 15 °F to 20 °F and to account for an estimated increase in
pumping head of 25 ft for closed-cycle versus once-through operation.
Exhibit 8-16 presents the new unit costs on a $/gpm basis. Exhibit 8-17 presents the
equations used for estimating costs based on unit generating capacity derived from
Exhibit 8-16 data using the gpm/MW values shown.
Exhibit 8-16. Costs for New Units and Repowering Based on GPM
Costs and Generating
Output Reduction
Capital Cost -
Repowering (CC)
Capital Cost - New Unit
with Intake (CC)
Fixed O&M Cost
(OMF)
Variable O&M -
Chemicals (OMC)
Variable O&M - Pump
& Fan Power (OMV)
Energy Penalty - Heat
Rate (EP) Non-nuclear
Energy Penalty - Heat
Rate (EP) Nuclear
Equation
CC = DIF(gpm) x Constant
CC = DIF(gpm) x Constant
OMF = DIF(gpm) x Constant
OMC= DIF(gpm) x Constant
OMV= DIF(gpm) x Constant
EP=MWS x Constant
EP=MWS x Constant
Constant
Adjusted for
Optimization
(2009)
$124a
$0
$1.27
$1.25
0.0000237
0.000
0.000
Add for 25%
Plume
Abatement
$30
$0
$0.25
$0.00
0.00000078
0
0
Baseline
O&M
Adjustment13
-$0.58
-$0.86
Total Adjusted
Net Cost
$154
$0
$0.94
$0.39
0.0000245
0
0
B Based on midpoint between easy retrofit ($169/gpm) and tower only ($80/gpm).
b Adjustment reflects deduction of O&M costs associated with traveling screens that would have been installed in the baseline once-
through system.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
Exhibit 8-17 Costs for New Units Based on Generating Capacity
Costs and Generating
Output Reduction
Capital Cost - New Unit with
New Intake (CC)
Fixed O&M Cost (OMF)
Variable O&M - Chemicals
(CMC)
Variable O&M - Pump & Fan
Power (OMV)
Energy Penalty -Heat Rate
(EP) Non-nuclear
Energy Penalty -Heat Rate
(EP) Nuclear
Equation
CC = MWS x Constant
OMF = MWS x Constant
OMC= MWS x Constant
OMV= MWS x Constant
EP=MWS x Constant
EP=MWS x Constant
Units
GPM/MW
Dollars
Dollars
Dollars
MW
MW
MW
Coal (42%
Efficient)
390
$0
$366
$151
0.0077
0
0
Combined
Cycle (57%
Efficient)
200
$0
$188
$77
0.0040
0
0
Nuclear
(33.5%
Efficient)
680
$0
$639
$262
0.0134
0
0
Downtime
Each of the new units will involve extensive construction activities that would result in a
prolonged construction downtime regardless of the cooling system requirements. Thus,
no downtime costs are assessed for new unit compliance. The same assumption was used
for repowering.
Energy Penalty
Energy penalty costs associated with net changes in parasitic energy requirements
between once-through and closed-cycle cooling are included in the O&M cost estimates
shown in Exhibit 8-17. For the heat rate penalty, new unit construction will involve new
steam turbines, condensers, and cooling towers using an optimized design. As such, the
system design can be tuned such that heat rate penalty that would otherwise be associated
with replacing the once-through system with a closed-cycle cooling system at an existing
facility is assumed to be minimal. Thus, no costs are assessed for the heat rate penalty.
Also, no costs for heat rate penalty were assessed for repowering, since it is assumed that
in most cases the project will involve the replacement of the steam turbines, condensers,
and cooling towers using an optimized design as well.
8.4.2 Compliance Costs for New Manufacturing Units
The projected baseline manufacturing unit process design and cooling water technology
would be based on an estimate of the response to the permitting authorities' application
of existing requirements including 316(b), applicable industrial water use and discharge
standards (e.g., categorical standards), and BPJ. Also, it has become standard practice for
industries to adopt water use reduction and reuse practices wherever practical. The
construction of a new unit provides a perfect opportunity to employ such measures to an
extent that would not be possible for existing units. In many cases, it is likely that the
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
existing regulatory requirements and practices would have resulted in a further reduction
in the cooling flow than for similar but older units. Thus, the baseline cooling AIF for
"new units" at manufacturers should, in most cases, be much smaller than the AIF for a
comparable existing unit. This is especially true for replacement units that perform a
similar function or produce a similar product, since economic factors such as the need to
increase process efficiencies are often driving factors in the decision to replace an
existing unit.
For new units in general, EPA has noted the following differences in costs between a
closed-cycle cooling retrofit at an existing facility compared to closed-cycle cooling at a
"new unit:"
• New units can incorporate closed-cycle cooling in a more cost-effective manner.
• The duration of new unit construction is sufficiently long that there would be, in
nearly all circumstances, no net increase in "construction downtime."
• Where new intakes or major components of the existing once-through intake and
cooling system must be constructed/upgraded, the capital costs of closed-cycle
cooling for new units are comparable to the capital costs of once-through cooling.
• The cooling system costs usually comprise less than 1 percent of the total costs of
a new unit.
• Reconstruction allows the use of an optimized cooling system design that can
minimize any system efficiency losses associated with conversion to closed-cycle.
• The fact that a large proportion of intake flow is used for process water and other
non-cooling purposes greatly increases the opportunity to design and incorporate
cooling water reuse strategies within the new unit.
• Where the new unit comprises only a portion of the plant upgrades, cooling water
reduction may be accomplished through reuse at other units within the plant.
• The modular nature of closed-cycle cooling allows for the limited application of
closed-cycle cooling only to the portion of cooling flow necessary to meet any
additional reductions not accounted for by any other reuse/reduction strategies
employed.
• The modular nature of closed-cycle cooling allows for the use of cooling system
designs specifically tailored to process requirements and vice versa.
• The modular nature of closed-cycle cooling and the flexibility inherent in
rebuilding a process system allows for more optimum placement of cooling tower
units, thus minimizing piping costs.
• New unit construction provides a lower cost opportunity to install variable speed
pumps and other system controls in cooling system applications. Flow reductions
associated with the use of variable speed pumps and other controls can result in
benefits associated with reduced flow and pumping energy costs and better
process control.
For power generation facilities that use once-through cooling, process water typically
constitutes a few percent or less of the total intake volume and the majority of the intake
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
flow is used for non-contact cooling purposes. A review of the responses to the detailed
technical survey showed that the median and average values for the percent of design
intake flow used for cooling purposes reported for each separate cooling water intake at
power generation facilities were 100 percent and 85 percent, respectively.
In contrast, most industrial manufacturing operations utilize a substantial portion of
intake water for non-cooling purposes and the same median and average values for
manufacturing facilities were 50 percent and 52 percent, respectively. In addition, the
cooling flow component at manufacturers will in many instances include contact cooling
water which would not be subject to the "new unit" requirements, thus decreasing the
proportion of cooling flow subject to the "new unit" requirements. This is consistent
with the NCCW/DIF ratios shown in Exhibit 8-9 ranging from 32 percent to 65 percent.
Given this, it is reasonable to assume a "typical" manufacturing unit may use less than 50
percent of flow for cooling purposes of the type that may be subject to the "new unit"
requirements. Theoretically, this "typical" facility should be able to reuse 100 percent of
the cooling water in place of the process component. Thus, the "typical" manufacturing
facility should be capable of designing a "new" process that could meet the "new unit"
requirements through water reuse alone. EPA observed extensive use of innovation and
water reuse during site visits at some manufacturing facilities. Such reuse opportunities
may be limited at facilities that use brackish or saltwater for cooling, but EPA estimates
that only 7 percent of manufacturing plants do so.
Since this 50 percent value is the median of all reported manufacturing cooling water
intake systems, at least half of manufacturing cooling water systems have the potential to
meet the "new unit" requirements simply by reusing non-contact cooling water as process
water. For the remainder, modifications to the process that reduce cooling water use
(e.g., use of variable speed pumps) may provide additional reduction. For some, there
may be a need to install cooling towers for the cooling flow component that cannot be
reused. This, however, will in most instances be a small portion of the total intake flow.
Also, in many cases the "new unit" will comprise only a portion of the entire
manufacturing facility and there may be other process units and plant operations nearby
that could reuse the cooling water in order to meet the flow reduction requirements.
For new units that would require building or rebuilding a once-through intake, EPA has
found that the capital costs of the new intake and screen technology which requires deeper
pump and intake wells to accommodate source water depth variations will be comparable
and possibly higher than the capital costs for closed-cycle technology. In these cases,
closed-cycle may have slightly higher O&M costs for pump and fan energy, but these costs
may be offset by other cost savings such as reductions in water treatment costs.
The definition of new manufacturing units limits the applicability of closed-cycle
requirements to new units that involve major construction activities that would involve
construction of substantial portions of the process and ancillary equipment. As such, it is
assumed that the reconstruction activities would involve substantial downtime periods
that would be of similar or more likely greater duration than required for construction and
tie-in activities associated with the closed-cycle cooling technology alone.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
Given all of this, EPA concluded that only a small portion of new units would need to
meet new unit flow reduction requirements through increased use of closed-cycle cooling
over what would have been built under existing regulatory requirements. As a result,
EPA concluded that the associated net costs would be minimal. Due to the fact that costs
are expected to be minimal and due to the difficulty inherent in developing estimates
given the complexities of water use within multiple industries and multiple processes
within each industry, EPA chose not to assign any cost for entrainment mortality
reduction compliance for this small component.
8.5 Impingement Mortality Costs at Intakes with Cooling
Systems Required to Install Closed-Cycle Cooling
Even after installation of a closed-cycle cooling system, the intake for the remaining
water withdrawals (i.e., makeup flow) still must comply with the EVI requirements. If the
existing intakes at a facility retrofitting to cooling towers were determined to be EVI-
compliant under current (i.e., once-through) operating conditions, then no additional costs
were assigned. For intakes that were not currently compliant, the intakes were re-
evaluated to determine if the flow reduction from installation of a closed-cycle cooling
system would result in EVI compliance via the 0.5 ft/sec intake velocity threshold. This
was done by first estimating the reduced total intake flow after installing closed-cycle
technology based on the assumption that the NCCW flow component would reduce flow
by a minimum of 92 percent.27 The flow reduction volume was subtracted from the
MRTF to determine the reduced total flow volume.
The intake screen velocity after implementation of closed-cycle cooling was then
estimated assuming the screen velocity reduction would be proportional to the flow
reduction. This was based on the assumption that the existing total screen or intake
surface area would remain the same. If the revised screen velocity was lower than 0.45
9R
fps, then it was assumed the existing intake would become EVI compliant after
implementation of closed-cycle cooling. For nearly all of the power generation facilities,
the estimated through-screen velocity after implementation of closed-cycle cooling was
lower than 0.5 fps and therefore no EVI technology compliance costs were assessed at
power plant intakes required to install closed-cycle cooling.
For those manufacturing plant intakes deemed not EVI compliant after retrofitting to
closed-cycle cooling, the EVI technology cost methodology was the same as described
above for intakes not required to install closed-cycle cooling. The only difference was
that, for those technologies that could be sized independently of the existing intake
technology (e.g., wedgewire screens, larger intakes, or velocity caps), the design flow
(MRE?) was further reduced by subtracting the estimated reduction in the NCCW flow
component associated with closed-cycle cooling.
27 A closed-cycle flow reduction value of 92 percent was selected as a conservative (smaller flow
reduction) estimate. Actual reductions are expected to be higher depending on condenser temperature rise
and cycles of concentration.
28 Instead of 0.5 fps, a more conservative value of 0.45 fps was selected as the compliance threshold to
account for potential unequal distribution of flow reductions between intakes and pumps.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 8: Costing Methodology
8.6 Costs for Each Regulatory Alternative
As described in the preamble, EPA is presenting three regulatory options in the proposed
rule. One option would require only impingement mortality at all facilities (i.e., modified
Ristroph screens everywhere), a second would require impingement mortality and
entrainment mortality at all facilities (i.e., wet cooling towers everywhere), and a third
would require impingement mortality at all facilities and entrainment mortality at
facilities with a design intake flow greater than 125 MGD. In addition, entrainment
reduction is required for all "new units" as defined in the preamble.
The sections above describe how facility-level costs were derived for each set of
requirements (either impingement mortality or entrainment mortality). To calculate the
total cost for a regulatory alternative, the facility-level costs for the applicable
requirements were simply summed. For example, for the option where cooling towers
are required at each facility with a DIP greater than 125 MGD, EPA used facility-specific
data to identify model facilities that fell above and below the flow threshold and used the
cost that corresponded to the appropriate compliance response. These facility-level costs
are then used to calculate national level economic impacts, as described below.
8.7 Compliance Costs Developed for Analysis of National
Economic Impacts
To assess the national economic impacts of its regulatory options, EPA conducted several
analyses; these are documented in the EBA. As part of these analyses, EPA conducted a
modeling analysis using the Integrated Planning Model (IPM) to develop a worst-case
impact analysis for power generators.29 EPA can conclude that if no national economic
impacts were observed as a result of the worst-case option, then less costly regulatory
options would also have no national economic impacts. This section describes the
technical data used in developing the IPM modeling; for more information, see the EBA.
In contrast to the model facility costing approach, the IPM model requires an estimate of
facility-level costs for all existing facilities (including those facilities that completed an
STQ).30 Facility-level costs were calculated by first estimating costs for the same subset
of facilities used in the model facility approach described above. To derive costs for STQ
facilities, EPA then aggregated the data to derive cost equations that were used to
calculate STQ facility-level costs using DIP as a scaling factor.
8.7.1 Selection of DIP as the Primary Scaling Factor for Power Plants
Several power plant attributes related to facility size were evaluated to determine which
would best serve as input values for the IPM model cost equations. The use of plant
generating capacity was evaluated by comparing the year 2000 steam generating capacity
to the DIF reported in the detailed year 2000 surveys for plants with once-through
cooling systems. It was concluded that there was insufficient correlation between steam
30
' For a detailed discussion of the IPM analysis, see the EBA.
The DIF for facilities that completed the short technical questionnaire was estimated on the basis of the
average daily flow as described in the preamble to the 2004 Phase II final rule. See 69 FR 41650.
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Chapter 8: Costing Methodology § 316(b) Existing Facilities Proposed Rule - TDD
generating capacity and the DIP to use the generating capacity as the sole basis for
estimating cooling system size and costs.31
Because the cost derivation methodologies used by EPA in the past and by EPRI for
developing cooling tower retrofit costs used the design cooling water flow rate (i.e., the
DIP), the DIP was selected as the basis for estimating model facility costs. Where such
data were not available, the DIP was estimated using the average ratio of DIP to steam
generating capacity (gpm/MW) for those facilities with once-through cooling systems.
The cost data used to derive the national average technology cost equations relied on data
only from facilities that reported design cooling water intake flow volumes in the detailed
surveys. Exhibit 8-18 below shows the equation used to estimate DIP on the basis of
steam generating capacity for facilities where insufficient design or actual flow data were
available to estimate the DIP. This equation was used only for facilities that did not
complete a technical questionnaire (short or detailed) and was estimated using a formula
based on the overall average DIF/MW ratio for power generators with once-through
cooling systems with DIP greater than 50 MGD.
Exhibit 8-18. Estimation of DIF Where No DIF Data Exists
Design Intake Flow (DIF)
Equation
DIF = MWS x constant
Constant
707
Units
gpm
MWS = Megawatts of steam = Total facility steam electric generating capacity.
The reported or estimated DIP volumes are used as input values in the cost-estimating
equations so that the average national technology costs can be scaled to account for
differences in plant/intake size.
8.7.2 Development of IM&EM Control Costs for IPM Model
The IPM Model facility cost equations for IM&EM controls were derived using the
intake technology cost data described above for each model facility intake. As described
above, cost modules were assigned as shown in Exhibits 8-1 and 8-2.
The first step to derive the IPM model facility cost equations was to derive a single value
for each cost item for each facility. Total costs for each facility were derived by
summing the capital, O&M, and pilot study costs of each intake. For most facilities, the
cost module was the same for all intakes, so single facility-level values were assigned for
the net downtime and the service life on the basis of the most common cost module
assigned to the intakes.
Various methods for using this data to estimate costs were evaluated, including using the
between-facility average or median of the $/gpm ratios, and using trend lines derived by
31 Theoretically, for once-through cooling systems, cooling water flow should have correlated well with
steam generating capacity, but it did not. The following are likely reasons for the lack of good correlation:
the fact that the temperature rise across the condenser (AT) can vary between plants, the fact that even those
plants considered as once-through can use varying amounts of closed-cycle cooling for some of the
generating capacity, and the fact that reported design intake flow might include substantial volumes of
water used for other purposes.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
Excel (which uses a least squares method). It was concluded that a simple straight-line
equation with Y-intercept equal to "0" using the overall between-facility average of the
individual facility cost to DIP ratios ($/gpm) represented a reasonable estimate for the
national model facility costs.
After deriving the facility-level costs, weighted averages of the cost to DIP ratio ($/gpm)
were calculated for all facilities that had compliance costs (i.e., facilities with zero costs
were not included). The same facility weights described above were used. Weighted
average values for the facility net construction downtime and technology service life
were also calculated. The net O&M fixed component was calculated as a portion of the
net O&M costs using a factor derived from the weighted average of the ratio of fixed
gross technology O&M to the total gross technology O&M. Exhibits 8-19 and 8-20
below present the model facility cost equations for IM reduction technology based on
modified Ristroph traveling screens or equivalent for facilities with DIP greater than or
equal to 10 MOD and DIP less than 10 MOD, respectively.32 Exhibits 8-21 and 8-22
present the service life and calculated technology net construction downtime.
Exhibit 8-19. Cost Equations for Estimating Model Facility Costs of Impingement
Mortality Controls for the IPM Analysis for Facilities with DIF > 10 MGD
Cost Item
Capital Cost (CC)
Pilot Study costs (PC)
Net O&M Cost (OM)
Fixed Net O&M Cost (OMF)a
Variable Net O&M (OMV)
Equation
CC = DIF(gpm) x Constant
PC = DIF(gpm) x Constant
OM = DIF(gpm) x Constant
OMF = DIF(gpm) x Constant
OMV = DIF(gpm) x Constant
Constant
13.1
0
0.78
0.45
0.33
Output Units
2009 Dollars
2009 Dollars
2009 Dollars
2009 Dollars
2009 Dollars
' Fixed O&M component based on values for compliance gross O&M
Exhibit 8-20. Cost Equations for Estimating Model Facility Costs of Impingement
Mortality Controls for the IPM Analysis for Facilities with DIF < 10 MGD
Cost Item
Capital Cost (CC)
Pilot Study costs (PC)
Net O&M Cost (OM)
Fixed Net O&M Cost (OMF)a
Variable Net O&M (OMV)
Equation
CC = DIF(gpm) x Constant
PC = DIF(gpm) x Constant
OM = DIF(gpm) x Constant
OMF = DIF(gpm) x Constant
OMV = DIF(gpm) x Constant
Constant
120.4
0
8.06
3.42
4.64
Output Units
2009 Dollars
2009 Dollars
2009 Dollars
2009 Dollars
2009 Dollars
1 Fixed O&M component based on values for compliance gross O&M
32 EPA also derived separate model facility cost equations for facilities with DIF less than 10 MGD and
those with DIF greater than or equal to 10 MGD to account for the notable difference in unit costs for the
low-flow intakes that results from the different approach used in assigning compliance technologies, plus
the fact that the equations used to derive the cost module cost estimates tended to produce higher $/gpm
rates at lower flow levels.
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Chapter 8: Costing Methodology
§ 316(b) Existing Facilities Proposed Rule - TDD
Technology Service Life
Estimates of technology service life were also required for the economic models. In the
2004 Phase II economic analysis, EPA assumed a useful life of 10 years for nearly all of
the compliance technologies, with the exceptions that a useful life of 30 years was used
for cooling towers and a useful life of 20 years was used for condenser upgrades
associated with the cooling tower retrofit. Also, one-time costs such as initial permitting
and connection downtime were annualized over a 30-year period, which was the
maximum time period for the technology cost analysis.
EPA has re-evaluated the estimated service life of each compliance technology based on
various sources of information and BPJ. Exhibit 8-21 presents the revised service life
estimates for all of the compliance technology modules used or considered for use in the
economic analyses.
Exhibit 8-21. Estimated Technology Service Life
Module No.
-
1
2
2a
3
4
5
6
7
8
9
10
10.1
10.2
10.3
11
12
13
14
Module Description
Cooling Towers
Replace Screen with Coarse Mesh Ristroph Traveling Screen
with Fish Handling and Return System
Replace Screen with Fine Mesh Ristroph Traveling Screen with
Fish Handling and Return System
Add Fine Mesh Overlay Screens Only
Add New Larger Intake Structure with Coarse Mesh Ristroph
Traveling Screen and Fish Handling and Return
Relocate Intake to Submerged Near-shore (20 M) with Passive
Screen (1.75 mm mesh)
Add Fish Barrier Net
Aquatic Fish Barrier (Gunderboom)
Relocate Intake to Submerged Offshore with passive screen
(1.75 mm mesh)
Add Velocity Cap at Inlet
Add Passive Fine Mesh Screen (1.75 mm mesh) at Existing Inlet
of Offshore Submerged
Module 2 plus Module 5
Module 2a plus Module 5
Module 3 plus Module 5
Module 1 plus Module 5
Add Double-Entry, Single-Exit with Fine Mesh, Handling and
Return
Relocate Intake to Submerged Near-shore (20 M) with Passive
Fine Mesh Screen (0.75 mm mesh)
Add 0.75 mm Passive Fine Mesh Screen at Existing Inlet of
Offshore Submerged
Relocate Intake to Submerged Offshore with 0.75 mm Passive
Screen
Service Life (Years)
30
20
20
20
25
30
30
30
30
30
30
20
20
25
20
20
30
30
30
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 8: Costing Methodology
Exhibit 8-22 presents the model facility technology net construction downtime and
service life.
Exhibit 8-22. Technology Downtime and Service Life for Model Facility Costs of
Impingement Mortality Controls for the IPM Analysis
Net Construction Downtime
Service Life
Units
Weeks
Years
Facilities with DIP >10 MGD
0.3
20a
Facilities with DIP <10 MGD
1.9
25 a
B Actual calculated values were 20.7 years for 510 MGD and 27.5 years for <10 MGD. Values were revised to obtain
conservative rounded values more amenable to use with IPM model.
8.7.3 Development of Closed-Cycle Cooling Tower Costs for IPM
Model
For the IPM analysis, the model facility costs for closed-cycle cooling have already been
derived; they are the same equations from Exhibit 8-8. The difficult cooling tower
retrofit capital costs were used to further reflect worst-case conditions. The net
construction downtime estimates used to derive the IPM model costs are shown in
Exhibit 8-10.
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Chapter 9: Impingement Mortality and
§ 316(b) Existing Facilities Proposed Rule - TDD Entrapment Reduction Estimates
Chapter 9: Impingement Mortality and Entrainment
Mortality Reduction Estimates
9.0 Introduction
This chapter presents impingement mortality and entrainment mortality reduction
estimates associated with each of the regulatory options EPA considered in developing the
proposed Existing Facilities rule. EPA estimated impingement mortality and entrainment
mortality reductions to evaluate the effectiveness of different treatment technologies. EPA
also used this information in analyzing potential benefits associated with the proposed rule.
See the EEBA for more details on these analyses.
9.1 Technology Reduction Estimates
EPA's regulatory options (see the preamble for discussion of the options) are based on the
following technologies:
• Modified Ristroph traveling screens with a fish return
• Low intake velocity
• Barrier nets
• Flow reduction as achieved by wet mechanical draft cooling towers
EPA's methodology for estimating impingement mortality and entrainment reduction for
these technologies varies depending on available data.
9.1.1 Screens
As explained in Chapters 2 and 11 of this document, EPA developed a performance
database that analyzed quantitative data on the efficacy and impingement mortality and
entrainment reduction associated with various technologies. This analysis formed the
basis for establishing the performance standard for impingement mortality at 88 percent
annual survival.
This analysis does not include an estimate of shellfish morality reductions because EPA
does not have comprehensive source water characterization data for shellfish. Therefore,
EPA is unable to estimate shellfish counts either before or after impingement controls. As
a result, the reductions are understated.
9.1.2 Low Intake Velocity
A facility that reduces its intake velocity to 0.5 ft/sec or below is assumed to meet the
performance standard for impingement mortality. As with screens, the reduction in
mortality is also assumed to be 88 percent. This likely understates organism survival,
because EPRI's fish swim speed study (in addition to other data collected by EPA; see
9-1
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Chapter 9: Impingement Mortality and
Entrapment Reduction Estimates § 316(b) Existing Facilities Proposed Rule - TDD
DCN 10-6705) shows that greater than 94 percent of studied fish can avoid an intake
structure when the intake velocity is 0.5 ft/sec or less.
9.1.3 Barrier Nets
Facilities located on oceans, tidal rivers and estuaries are required to install barrier nets (or
equivalent performing technologies). Passive intake technologies (such as cylindrical
wedgewire) and screens with no carry-over (such as dual flow screens) are assumed to also
meet this standard. Facilities with traveling screens were also costed for the installation of
barrier nets.
As discussed in 9.1.1, EPA was unable to estimate any impingement mortality reductions
for shellfish. As a result, the reductions are understated.
9.1.4 Flow Reduction Commensurate with Closed-Cycle Cooling
As explained in Chapter 6, both entrainment and impingement (and associated mortality) at
a particular site are generally considered to be proportional to intake flow. In other words,
if a facility reduces its intake flow by 50 percent, it similarly reduces the amount of
organisms subject to impingement and entrainment by 50 percent. For the traditional
steam electric utility industry, available data1 demonstrate that facilities located in
freshwater areas that have closed-cycle, recirculating cooling water systems can,
depending on the quality of the make-up water, reduce water use by up to 97.5 percent
from the amount they would used if they had once-through cooling water systems.
Similarly, steam electric generating facilities that have closed-cycle, recirculating cooling
systems using salt water can reduce water usage by up to 94.9 percent when make-up and
blowdown flows are minimized.2
Accordingly, a facility that is required to reduce its flow commensurate with closed-cycle
cooling would realize a significant reduction in its impingement and entrainment impacts.
9.2 Assigning a Reduction to Each Model Facility
As explained in Chapter 8 of this document, EPA estimated costs for each model facility to
comply with the regulatory options it considered for the proposed rule. In general, to
develop model facility costs, EPA reviewed the impingement mortality and entrainment
mortality requirements for a particular option and determined if each model facility would
be able comply with the requirements based on their existing technologies (e.g., has
existing intake technologies that serve as the basis for the option or exhibit equivalent
performance). For each model facility that EPA projected would not be able comply with
the regulatory option requirements, EPA estimated costs to install and operate additional
impingement mortality and entrainment mortality minimization technologies. EPA's
assignment of costs to model facilities is relevant to its impingement mortality and
1 See Chapter 6 of the TDD.
2
See Chapter 2 of the TDD for additional discussion of how these flow reduction values were derived.
9-2
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 9: Impingement Mortality and
Entrapment Reduction Estimates
entrainment mortality reduction estimates because EPA only assigns reduction estimates to
model facilities that incur compliance costs.
For example, if a facility is subject to impingement mortality requirements but has only a
conventional coarse mesh traveling screen, it would have been assigned costs to replace the
screen with a modified Ristroph screen (or similar technology). Accordingly, a reduction
in impingement mortality of 88 percent was assigned to this facility to reflect the improved
performance of the new screens.3
Once EPA determined a compliance response for each model facility under a given
regulatory option, EPA similarly assigned impingement mortality and entrainment
reductions, as applicable. EPA assigned impingement mortality and entrainment mortality
reductions as illustrated in Exhibit 9-1 below:
Exhibit 9-1. Reductions in Impingement Mortality and Entrainment Mortality
Control Technology Assigned
Closed-cycle cooling (fresh water)
Closed-cycle cooling (salt water)
Modified Ristroph Screens
Impingement Mortality
Reduction
97.5%
94.9%
88%
Entrainment Mortality
Reduction
97.5%
94.9%
0%
A facility may be subject to one or both requirements, as shown in the examples below:
• a facility that does not have modified Ristroph screens (or an intake velocity of 0.5
ft/sec) would reduce impingement mortality by retrofitting to one of the two
impingement mortality technologies
• under Option 2, a facility with a design intake flow over 125 MGD with no
flow-reduction technologies would be subject to both impingement mortality and
entrainment mortality requirements
• under Option 3, any facility with a design intake flow over 2 MGD with no
flow-reduction technologies would be subject to both impingement mortality and
entrainment mortality requirements
• a facility with an existing closed-cycle cooling system that has poor performing
traveling screens would reduce impingement mortality by retrofitting to one of the
two impingement mortality technologies
• a facility that was projected to retrofit closed-cycle cooling also often accrues
benefits from both flow reduction and impingement mortality reduction. In other
words, a facility that would be required to reduce its flow commensurate with
closed-cycle cooling would be assigned a 97.5 percent or 94.9 percent reduction in
both EVI and EM. However, because these facilities are still subject to EVI
requirements, EPA assumed that these facilities would also reduce EVI by 88
percent over and above the reduction realized by the reduction in flow (due to either
installing new screens or by significantly reducing the intake velocity). As a result,
Note that this does not imply an 88 percent improvement over conventional screens; it simply represents the
improved survival of organisms.
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Chapter 9: Impingement Mortality and
Entrapment Reduction Estimates § 316(b) Existing Facilities Proposed Rule - TDD
many of these facilities were assigned 99.7 percent (97.5 percent + 88 percent of
remaining 2.5 percent) or 99.39 percent (94.9 percent + 88 percent of 5.1 percent).
• no reductions in shellfish were estimated under any option
A large number of existing facilities use multiple intake structures. To account for this
configuration, a flow-weighted average was used across each intake. As before, reductions
are based on the engineering costs and compliance response for each intake; intakes that
are assigned a new technology were also assigned a reduction. For example, if a facility
has two intakes with equal design intake flows but one uses a modified Ristroph screen and
one does not, the impingement mortality reduction would be 44 percent—the
flow-weighted result of having one compliant intake and one non-compliant intake.
As such, there are a wide variety of compliance responses among the model facilities.
Facilities may also exhibit partial compliance; for example, some facilities have a partial
(or combination) closed-cycle system, where some units utilize a closed-cycle system and
others use once-through cooling. Other facilities may have one intake with a modified
Ristroph screen and another without. In these cases, EPA assumed that those intakes using
the compliant technology would be considered as complying with impingement mortality
or entrainment mortality requirements and calculated impingement and entrainment
reductions using a flow-weighted average across all of the facility's intakes.
9.2.1 Entrainment Mortality
In the 2004 Phase II rule, EPA made the assumption that any entrained organism died
(i.e., 100 percent mortality for organisms passing through the facility) and any organism
not entrained survived. In other words, if a technology reduced entrainment by 60 percent,
then EPA estimated 40 percent of the organisms present in the intake water would die in
comparison to 100 percent in the absence of any entrainment reduction. As discussed in
the preamble to the proposed Existing Facilities rule, EPA changed its approach from
addressing entrainment (i.e., exclusion) to entrainment mortality. The reductions
discussed in this chapter reflect those changes.
9.2.2 In-Place Technologies
If a facility has already installed a technology that is compliant with the applicable EVI or
EM standards, it is not assigned a technology (i.e., it is not assigned technology costs) and
therefore is not assigned a reduction in IM or EM. In all other cases, the full reduction for
EVI or EM is applied to that intake structure. See Exhibits 8-1 and 8-2 for a decision tree of
how compliance technologies were assigned.
9.2.3 Summary of Options
Exhibit 9-2 summarizes the percent of flow and environmental impacts addressed by each
option under the proposed rule.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 9: Impingement Mortality and
Entrapment Reduction Estimates
Exhibit 9-2. Summary of Options
Option
1 &4(IMForAII, IM for
DIP >50 MGD)
2 (IM for All, EM for
AIF>125MGD)
3 (IM for All, EM for All)
Percent of Design Flow
Covered (%)
Impingement
Mortality
100
100
100
Entrainment
Mortality
0
87
100
Applies To
Impingement
Mortality
X
X
X
Entrainment
Mortality
X
X
9-5
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 10: Non-water Quality Impacts
Chapter 10: Non-water Quality Impacts
10.0 Introduction
For the 2004 Phase II rule, EPA conducted an analysis of non-water quality impacts
resulting from the conversion of some facilities to recirculating wet cooling towers.
These impacts include increased air emissions due to energy penalties, vapor plumes,
noise, salt or mineral drift, water consumption through evaporation, and solid waste
generation due to wastewater treatment of tower blowdown (see the 2002 proposed rule
TDD Chapter 6, DCN 4-0004). For the proposed rule, EPA reviewed these impacts and
supplemented the air emissions, vapor plumes, noise, and evaporative consumption
analyses as described in the following sections. EPA also briefly reviewed the data
available on non-water quality impacts of thermal effluent discharges.
10.1 Air Emissions Increases
In developing the 2002 proposed Phase II rule, EPA estimated the incremental increases
in emissions for 59 model power plants expected to retrofit from once-through cooling to
recirculating wet cooling towers under the preferred alternative (see the 2002 proposed
rule TDD Chapter 6, DCN 4-0004).l These model facilities included nuclear, combined-
cycle and fossil fuel-fired power plants. As described in the 2002 proposed rule TDD
and in the Environmental and Economic Benefits Analysis (EEBA) for the proposed rule,
facilities retrofitting to recirculating wet cooling towers incur an energy penalty due to
the increased electricity generation needed to compensate for the loss of efficiency
caused by the retrofitted cooling towers. This results in a slight increase in emissions
from the increased burning of fuel.2'3 Note that the current emissions rate calculations
discussed below do not reflect full implementation of the most recent air rule requirements.
For today's proposed rule, EPA used facility-specific power plant emissions (annual
average) data to estimate increased emissions under the proposed options presented in the
preamble to the proposed rule. EPA also conducted a geographical information system
(GIS) analysis of non-attainment areas and Phase II power plant locations to identify
areas of potential increased impact.
10.1.1 Incremental Emissions Increases
Facilities that retrofit to a cooling tower will experience a reduction in efficiency, as there
is a loss of efficiency in the turbine due to the higher temperature condenser water within
the cooling water system. The fans inside the tower also require electricity to operate.
1 The preferred alternative (Option 1) required facilities to meet performance standards based on waterbody
type and proportion of flow withdrawn for cooling. Under this option, 59 facilities were estimated to
comply through the installation of cooling towers.
2 See Table 6-1 from the TDD for the 2002 Phase II proposal for the estimated incremental increase in
emissions under the 2002 preferred alternative.
3 Increased emissions are not caused by the recirculating wet cooling tower itself, but by the fuel deficit
created by the additional energy needed for operation of the towers and a loss of turbine efficiency.
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Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
Collectively, these inefficiencies are known as the energy penalty. To compensate for the
loss of electricity generation, a facility could either operate more frequently (if it is not
already a baseload plant) or it could burn additional fuel. Both scenarios would lead to
an increase in the emission of air pollutants from the combustion of fossil fuels.
For today's proposed rule, EPA used a methodology similar to the one used in the 2002
proposed rule and TDD to estimate incremental increases in emissions under each of the
options considered. The data source for the Agency's air emissions estimates of CC>2,
SO2, NOX, and Hg is the EPA-developed database titled E-GRTD 2005. This database is a
compendium of reported air emissions, plant characteristics, and industry profiles for the
entire US electricity generation industry in the years 1996 through 2005. The database
relies on information from power plant emissions reporting data from the Energy
Information Administration of the Department of Energy. E-GRTD compiles information
on every major power plant in the United States and includes statistics such as plant
operating capacity, air emissions, electricity generated, and fuel consumed. This
database provided ample data for the Agency to conduct air emissions increases analyses
for the proposed rule. The emissions reported in the database are for the power plants'
actual emissions to the atmosphere and represent emissions after the influence of any
existing air pollution control devices.
E-GRTD, however, does not provide information on emissions of particulate matter (PM).
The data source for historic emissions rates of PM 2.5 and PM 10 is the EPA-developed
database titled National Emission Trends (NET). The NET database is an emission
inventory that contains data on stationary and mobile sources that emit criteria air
pollutants and their precursors. The NET is released every three years (e.g., 1996 and
1999) and includes emission estimates for all 50 States, the District of Columbia, Puerto
Rico, and the Virgin Islands. The database compiles information from EPA air programs
and the Department of Energy, and the information it contains for other parameters was
found to be consistent with the information found in E-GRTD 2005.
The model facility universe for each regulatory option represents those power plants that
are in scope for each option, for which some E-GRTD and/or NET data is available for
the desired parameters of CO2, SO2, NOX, Hg, PM 2.5, and PM 10. Although
manufacturing facilities are included in the universe of the proposed rule, there is no
readily available data on air emissions from manufacturing facilities. In addition, nuclear
power plants and facilities that already have closed cycle cooling towers are excluded
from the model universe, as they would not have to retrofit to cooling towers.
Furthermore, facilities that did not have readily available air emissions data were also
excluded from the model universe. Therefore, the model facility universe for this
evaluation only encompasses those power plants for which air emissions data is available
that do not already employ cooling towers, making it a subset of the total facilities
expected to be affected by the proposed rule.
Site-specific models for calculating air emissions increases are not appropriate for
estimating the national impact of the proposed rule and were not used in this analysis. In
addition, some studies have suggested that certain methods (e.g., EPA's AP-42 method
for estimating PM emissions from cooling towers) may overstate air emissions from
recirculating wet cooling towers (SWRCB 2010). One approach to generating an upper
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 10: Non-water Quality Impacts
bound estimate of air emissions increases at facilities included in the model universe
under each proposed option is presented in Tables 10A-1 (Option 2) and 10A-2 (Option
3) in the Appendix to this chapter. These tables represent facility-specific air emissions
increases and are based on the estimated energy penalty for each facility, the facility's
historic average electricity generation level, and its average historic emission rates.4 The
estimated incremental increases in emissions are not reported for facilities already
employing (or partially employing) cooling towers, nuclear and retired facilities, and
those facilities for which data is not available. Note that the discussions below on
greenhouse gases do not reflect recent or proposed regulations for limiting greenhouse
gas emissions, as the data is reported for 2005 and thus reflects operations prior to 2004.
These data predate the implementation of recent air rules; therefore, EPA expects that, in
most cases, these data do not reflect emissions after installation of scrubbers and other air
pollution control equipment. EPA intends to collect current emissions data (i.e., updated
E-GRTD and NET data through 2010 will be available some time in 2011), including
emissions after compliance with recent air rules, and to rescale these estimates.
Carbon dioxide
Carbon dioxide is not a criteria pollutant under the National Ambient Air Quality
Standards (NAAQS). Carbon dioxide is, however, a pollutant of concern on a global
scale, as it is a greenhouse gas. Several states, including California, Oregon,
Washington, Montana and Illinois, currently have rules for limiting carbon dioxide
emissions from electric generators. Several Northeastern and Mid-Atlantic states are
currently participating in a regional cap-and-trade program that limits carbon dioxide
emissions from electric generators, and similar systems are in development in the West
and Midwest. The cap and trade programs ensure that total emissions from all covered
entities fall below a cap that typically declines over time; however, it does not mandate
limits for individual entities, as is the case for performance standards (Pew Article 2010).
Sulfur Dioxide
Sulfur dioxide is one of the most regulated pollutants in the U.S. and is one of the criteria
pollutants under NAAQS. Electricity generation is the highest-contributing source of
sulfur dioxide emissions in the United States. Regional monitoring levels are generally
below NAAQS threshold levels, except for events at three monitoring sites in Hawaii that
have been suggested to be attributed to volcanic activity and therefore, as exceptional
events, are not considered for regulatory purposes. Annual average ambient sulfur
dioxide concentrations, as measured at area-wide monitors, have decreased by more than
70 percent since 1980. Currently, the annual average sulfur dioxide concentrations range
from approximately 1-6 parts per billion, which is well below the quantities expected to
affect human health (EPA 2010a).
4 Historic generation rates were obtained from E-GRID 2005. Historic emissions rates were obtained from
E-GRID 2005 and NET.
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Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
Nitrogen dioxide
Nitrogen dioxide is one of the most regulated pollutants in the U.S. and is one of the
criteria pollutants under NAAQS. Although electricity generation is the third-highest
contributor to nitrogen dioxide emissions in the Unites States, regional monitoring levels
have been well below NAAQS threshold levels, so no U.S. counties (as of the summary
data collected at the national level through 2008) have been considered to be out of
attainment in the past decade for this parameter (EPA 201 Ob). Annual average ambient
nitrogen dioxide concentrations, as measured at area-wide monitors, have decreased by
more than 40 percent since 1980. Currently, the annual average nitrogen dioxide
concentrations range from approximately 10-20 parts per billion (ppb), which is not
considered to be a sufficient quantity to affect human health (EPA 2010c).
EPA expects nitrogen dioxide concentrations will continue to decrease in the future as a
result of a number of mobile source (the highest contributing source of nitrogen dioxide
emissions in the United States) regulations that are taking effect in the past few years.
Nitrogen dioxide is, however, one of the two molecules (with volatile organic compounds
[VOCs] being the other) that facilitates the formation of ground level ozone, which is
also a criteria pollutant and often exceeds the NAAQS criteria.5 Therefore, in ground-
level ozone non-attainment areas, point sources of nitrogen dioxide and VOCs are tightly
controlled. In addition, more stringent controls for nitrogen dioxide and VOCs are
expected in the future (Lavalee 2008).
Mercury
Mercury is not one of the criteria pollutants under NAAQS, but is known to cause human
health impairments. However, mercury is typically not a pollutant that is sampled by the
regional monitoring equipment in each Air Quality Control Region. Many states have
begun efforts to inventory sources of mercury but have yet to set limits. Some states
have emissions limits, but most are sufficiently high that they are not exceeded (Lavalee
2008).
Particulate Matter
PM is one of the criteria pollutants regulated under NAAQS. It is measured as PM 2.5,
particles that are 2.5 micrometers in diameter and smaller, and PM 10, particles that are
10 micrometers in diameter or smaller. These are regulated pollutants because particles
smaller than 10 micrometers can, once inhaled, enter the lungs and cause serious health
effects. Electricity generation is the fourth highest-contributing source of PM in the
United States, both at the PM 2.5 and PM 10 levels (EPA 2010d).
Regional monitoring levels for PM 10 have generally been below NAAQS threshold
levels; PM 2.5 monitoring, however, has consistently indicated many areas of periodic
nonattainment of NAAQS standards since national regional monitoring began in 1999.
Even though annual average ambient PM has been steadily decreasing across the country,
5 See the maps in Appendix 10A-3; ozone is the pollutant with the largest number of non-attainment areas.
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 10: Non-water Quality Impacts
PM remains as a potentially significant environmental and human health concern (EPA
2010d).
As discussed in DCN 10-6954, increased emissions would be approximately 60 tons per
year if all drift is PMio. This document also noted minor drift management issues onsite
at facilities using salt water cooling towers and no negative consequences off-site.
Total Emissions Increases
Emission increases consist of: (1) stack emissions from increased burning of fuel as a
result of the energy penalty for retrofitting to a cooling tower (the turbine backpressure
penalty); (2) stack emissions from increased burning of fuel as a result of the energy
penalty for operating the cooling tower (the parasitic load); (3) cooling tower emissions
including water vapor (drift) and PM. For the options under which no facilities are
required to retrofit to wet cooling towers (Options 1 and 4), there would be no
incremental increase in air emissions. For those options under which EPA assumes a
subset of facilities would retrofit to wet cooling towers, EPA expects an increase in the
total air emissions. This increase excludes those facilities already employing cooling
towers. As seen in Appendix A to this chapter, the estimated energy penalty for each
facility would result in an increase over each facility's historic emissions rates for
average electricity generation levels.
Cooling tower particulate emissions can be mitigated through the use of drift
eliminators—shaped materials that collect small water droplets as they exit the tower.
Drift eliminators are capable of reducing drift to 0.0005 percent of the circulating water
volume, or approximately 0.5 gallons per 100,000 gallons of flow (OPC 2008). EPA
included capital costs for drift eliminators for all facilities expected to retrofit to wet
cooling towers.
In addition, some number of fossil fuel-burning power plants might close due to the
additional regulatory burden imposed the proposed rule. See the EBA for more
information. Those facilities projected to close are (in general) the oldest, least efficient,
and highest air emissions-producing sources. Therefore, the estimate of increased air
emissions associated with the retrofit to wet cooling towers reflects an upper bound
estimate.
Total Emissions Reductions
EPA believes projected total emissions from retrofits to cooling towers using currently
available data (Appendix A) reflect an upper bound estimate for several reasons. The
IPM modeling used in EPA's economic analysis indicates baseload generating units and
units forecast to continue production are generally comprised of the most efficient (and
therefore the lowest emitting) units, resulting in a potential reduction in total air
emissions. For example, the baseline closures are coal-fired units that are among the top
50 highest 862 emitting plants (Sourcewatch, DCN 10-6857). In addition, the current
emissions rate calculations do not reflect full implementation of the most recent air rules
or pending actions on greenhouse gases and global climate change. For example, the
2010 Air Transport Rule and other state and EPA actions would reduce remaining power
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Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
plant SC>2 emissions by 71 percent and NOX emissions by 52 percent. The mercury rule
would require utilities to install controls to reduce mercury emissions by 29 percent.
Since the actual emissions data used in EPA's analysis does not reflect full
implementation of these air rules, and since in many cases technologies to reduce
emissions have yet to be installed, both the baseline and any potential increase in
emissions are overstated. Finally, the latest tower fill materials and other cooling tower
technology improvements provide increases in cooling capacity. In some cases, cooling
towers provide cooling water at lower temperatures than available from the source water,
particularly during the summer months, resulting in lower turbine back pressure in the
summer when maximum power generation is desired. Despite these conservative
estimates, EPA concludes there is the potential for an increase in total emissions. At this
time, EPA lacks adequate data to conduct a more precise analysis of incremental
emissions.
10.1.2 CIS Analysis
As part of its review of the analyses of increased emissions, EPA conducted a GIS
analysis of expected pollutants from potentially affected facilities. Specifically, EPA
created maps with the locations of all power plants that would have been covered under
the 2004 Phase II rule overlaid with maps of non-attainment areas for the various criteria
air pollutants.6 At the time of the analysis, EPA did not have national data for
manufacturers; therefore, manufacturers were excluded from this analysis.
EPA created maps to identify non-attainment areas for the following pollutants:
• Carbon monoxide (CO)
• Lead (Pb)
• Particulate matter (PM10 and PM2.5)
• Ozone
• Sulphur dioxide (802)
Maps for each pollutant are found in Appendix 10A-3. For most pollutants, Phase II
power plants are generally located in areas that meet the NAAQS standards (i.e., are in
attainment).7 There are, however, a significant number of facilities are located in
nonattainment areas for PM2.5 and Ozone. Exhibits 10-1 and 10-2 show the data from
the maps in a tabular format.
6 EPA used data layers from the EPA Office of Air and Radiation's AQS Database. These data layers
reflect attainment status for criteria pollutants under NAAQS. Generally, concentrations of air pollutants
are monitored in the ambient air, usually on a county-by-county level. Areas that exceed the pollutant
levels specified by NAAQS can be classified by EPA as non-attainment. See
www.epa.gov/air/criteria.html for more details.
7 Facilities in Alaska and Hawaii are not shown; these states are in attainment for all criteria pollutants.
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§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 10: Non-water Quality Impacts
Exhibit 10-1. Phase II facilities in non-attainment areas (by pollutant)
Pollutant
Carbon monoxide (CO)
Lead
PM10
PM2.5
Ozone (8 hr)
Sulphur dioxide (SO2)
Number of facilities
0
1
7
145
174
2
Exhibit 10-2. Phase II facilities in non-attainment areas (by EPA Region)
Pollutant
Carbon monoxide (CO)
Lead
PM10
PM2.5
Ozone (8 hr)
Sulphur dioxide (SO2)
Number of facilities by EPA Region
I
0
0
0
4
23
0
II
0
0
0
22
33
0
III
0
0
0
37
28
1
IV
0
0
0
18
11
0
V
0
0
0
53
40
0
VI
0
0
0
0
20
0
VII
0
1
0
4
0
0
VII
0
0
0
0
3
1
IX
0
0
7
7
16
0
X
0
0
0
0
0
0
The geographic analysis shows that there not many Phase II power plants for which
nonattainment of carbon monoxide, lead, PM 10, and sulphur dioxide NAAQS standards
is likely to be a concern. There are some areas, however, where additional emissions of
PM 2.5 and ozone (8-hr) could be a concern, particularly for facilities several in EPA
Regions where there are significant numbers of Phase II facilities in non-attainment
areas.
10.2 Vapor Plumes
In 2002, EPA's assessment of vapor plumes resulting from a retrofit from once-through
cooling to recirculating wet cooling towers showed that these plumes have the potential
for exacerbated fogging and icing. High levels of fogging and icing have the potential to
create dangerous conditions for local roads and for air and water navigation. There are
some cases of wet cooling towers being built in close proximity to airports and highways
that could be susceptible to fogging and icing problems. In these cases, however, the
potential for dangerous conditions were mitigated by the installation of plume abatement
technologies during the construction of the cooling towers.
Plume abatement might also be necessary at certain types of locations, including
situations in which local residents or governments object to the visible plume, as it may
detract from a view that is valued by the community, or if the plume might create safety
problems such as reduced visibility on nearby roadways or icing on roads and bridges.
EPA included plume abatement technologies in its cost estimates for one-fourth of the
facilities expected to retrofit to wet cooling towers under each proposed option. The
Phase I support document (Table A-4) indicates that typical hybrid towers (one treatment
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Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
technique for vapor plumes) have capital cost factors of 2.5 to 3.0 and operations and
maintenance cost factors of 1.25 to 1.5 when compared to standard cooling towers made
of Douglas fir. Similarly, the EPRI documentation states that plume abatement capital
costs will be 2 to 3 times those of conventional mechanical draft towers. A number of
site-specific factors come into play to determine the selection of technology, but
appropriate assumptions for estimating national-level compliance costs can be made
regarding the impacts of these abatement technologies to the overall cost of the retrofit.
A full discussion of the costing methodology and assumptions used for the 2011
proposed rule is presented in Chapter 8 of this TDD.
10.3 Displacement of Wetlands or Other Land Habitats
As described in the 2002 proposed Phase II TDD, mechanical draft cooling towers can
require land areas of up to 1.5 acres for an average-sized new cooling tower.8 In 2002,
the Agency concluded that existing Clean Water Act Section 404 programs would more
than adequately protect wetlands and habitats for these land uses. EPA also determined
that the displacement of wetlands on an industrial site such as a large existing power
plant is not a probable outcome of cooling tower construction at most facilities. EPA
does not expect habitat displacement to be a significant problem for most facilities. EPA
believes for the proposed rule that existing Federal, state, and local programs for
maintaining and restoring wetlands are adequate to protect wetlands and no new analyses
were conducted.
10.4 Salt or Mineral Drift
As described in the 2002 proposed Phase II TDD, the operation of cooling towers in
either brackish or salt water environments can release water droplets containing soluble
salts, including sodium, calcium, chloride, and sulfate ions. Salt drift may also occur in
freshwater systems that operate recirculating systems at very high levels of concentration,
but based on EPA's site visits and the higher O&M costs of operating at the highest
cycles of concentration, EPA expects this is unlikely to occur at most facilities. Salt drift
from towers may be carried by prevailing winds and settle onto soil, vegetation, and
waterbodies. Under normal conditions drift does not carry very far from the originating
source and would require sustained high winds and high humidity to reach distances of
several hundred feet in any significant quantity (SWRCB 2010). In addition, drift-
reducing technologies called drift eliminators are often used to minimize salt and mineral
drift. (Also see the above discussion of particulate matter and EPA's assignment of drift
eliminators.) A review of GIS mapping of nuclear facilities shows the safety perimeter
and setback distances at nuclear facilities are large enough that drift reaching and settling
on neighboring properties is highly unlikely. Additional site-specific studies at Chalk
Point and St. Johns (Maulbetsch) suggest the impacts of drift are limited to the facility
property. As such, EPA does not expect drift to be a significant problem for most
facilities under any of the cooling tower options.
Size of "average" cooling tower is based on technology and cost assumptions used in developing the 2002
proposed Phase II rule.
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 10: Non-water Quality Impacts
10.5 Noise
Noise from mechanical draft cooling towers is generated by falling water inside the
towers plus fan or motor noise or both. However, power plant sites generally do not
result in off-site levels of noise more than 10 dB(A) above background (NRC 1996). The
amount of noise abatement required is a function of both the local community noise code
and the distance from the tower to the nearest sound receptor that must meet the specified
noise code. Noise abatement costs will be highest if a tower must be located near areas
with highly restrictive noise codes, such as residential areas.
Noise abatement features are an integral and inexpensive component of modern cooling
tower designs. (See the 2002 proposed TDD, Appendix B, Charts 2-1 through 2-6 for a
comparison of low-noise tower costs and other types of tower modifiers.) Facilities that
make use of cooling towers might expect the typical noise level to be approximately 70
dB within 50 feet of the tower (SPX 2009).9 Because sound levels diminish
approximately 5 dB per doubling of distance, and 55 dB falls between the sound level of
rainfall and normal conversation (and therefore would not be considered noise pollution),
a buffer of 400 feet would suffice for noise abatement at most sites. In addition, EPA's
"Protective Noise Levels" guidance found that ambient noise levels of 55 dB was
sufficient to protect public health and welfare and, in most cases, did not create an
annoyance (EPA 1978). As for noise pollution at the site itself, the New York State
Department of Environmental Conservation's "Assessing and Mitigating Noise Impacts"
policy states that 60-70 dB is the beginning of the threshold for annoyance in non-
industrial sites and that noise can exceed 65 dB (and up to 79 dB) in commercial or
industrial sites. A common goal is to keep new noise sources from increasing the overall
noise levels by 5-10 dB. Given that noise is measured on a logarithmic scale, adding a
cooling tower that operates with a sound level of approximately70 dB will be unlikely to
add a significant level of noise to an already noisy industrial site (NYDEC 2000). Given
that noise appears to dissipate relatively quickly (and the fact that many industrial sites
are large and a 400 foot buffer would not be a significant limitation), effects from noise
are not expected to be significant at most sites. There will certainly be some sites that
require noise mitigation, but the number of sites is likely to already be represented by the
analyses for plume and population density.
The cost contribution of low noise fans would comprise a very small portion of the total
installed capital cost of a retrofitted cooling system (on the same order as drift
elimination technologies). Where noise abatement materials maintenance costs are
higher (such as for larger towers), O&M costs should be commensurately reduced. Thus,
the net effect of this noise abatement technology design on cooling tower O&M costs is
expected to be minimal.
As such, the Agency is confident that the issue of noise abatement is not critical to the
evaluation of the environmental side effects of cooling towers. In addition, this issue is
often a matter of adverse public reactions to the noise and not environmental or human
health (i.e., hearing) impacts. The NRC adds further, "[n]atural-draft and mechanical-
draft cooling towers emit noise of a broadband nature...Because of the broadband
9 For additional technical discussion of noise mitigation, please see DCN 10-6652.
10-9
-------
Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
character of the cooling towers, the noise associated with them is largely
indistinguishable and less obtrusive than transformer noise or loudspeaker noise."
EPA included additional costs for noise abatement at approximately 25 percent of
existing facilities; see Chapter 8 of the TDD and DCNs 10-6671 and 6672. As such, EPA
does not expect noise abatement to be a significant problem for most facilities.
10.6 Solid Waste Generation
Recirculation of cooling water increases the volume of solid wastes generated because
some facilities (including most manufacturers) treat the cooling tower blowdown in a
wastewater treatment system before discharge, and the concentrated pollutants removed
from the blowdown add to the amount of wastewater sludge generated by the facility.
For facilities operating cooling towers in brackish or saline waters, the concentration of
salts within the tower and blowdown are a primary design factor. As such, these systems
can have elevated salt concentrations. However, the concentration of salts is generally a
treatable condition for blowdown from towers. In general, manufacturers tend to have
systems in place for treating this type of solid. EPA does not expect the impacts of solids
waste disposal to be a significant problem and did not further evaluate impacts from
solids waste disposal for the proposed rule.10
10.7 Evaporative Consumption of Water
Cooling tower operation is designed to result in a measurable evaporation of water drawn
from the source water. Depending on the size and flow conditions of the affected
waterbody, evaporative water loss can affect the quality of aquatic habitat and
recreational fishing. According to NUREG-1437 (NRC 1996), "water lost by
evaporation from the heated discharge of once-through cooling is about 60 percent of that
which is lost through cooling towers." NUREG-1437 goes on to further state that "with
once-through cooling systems, evaporative losses... occur externally in the adjacent body
of water instead of in the closed-cycle system." Therefore, evaporation does occur due to
heating of water in once-through cooling systems, even though the majority of this loss
happens downstream of the plant in the receiving water body due to the evaporation in
the heated effluent plume.
EPA acknowledges that evaporative losses from closed-cycle cooling towers are greater
than those from once-through cooling systems. At the national level, the rate of
evaporation can increase by a factor of 2 to 3 in closed-cycle systems. This conclusion is
consistent with research conducted by NUREG-1437 and the Electric Power Research
Institute (EPRI) that concluded that losses in closed-cycle systems are approximately 60-
80 percent greater (EPRI 2002).
10 EPA assumed no incremental costs for treatment of blowdown, as the issue is expected to be minor for
most facilities. For example, facilities on brackish waters are already discharging to waters with elevated
TSS. Additionally, many facilities (particularly manufacturers) already have wastewater treatment
capabilities in place.
10-10
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 10: Non-water Quality Impacts
The differences in evaporative losses are minimal in terms of gallons lost and in most
cases are minor compared to river flow. In areas where water resources are limited (e.g.,
the desert southwest or the recently drought-stricken southeast), once-through cooling
may not be a prudent option for new facilities and it may be a liability for existing
facilities. EPA witnessed this first hand in its site visits, as several facilities retrofitted to
closed-cycle cooling in spite of drought conditions (see, e.g., the site visit report for
McDonough). Similarly, for facilities located on smaller waterbodies, evaporative losses
from once-through cooling will be higher since the effluent comprises a larger percentage
of the receiving stream, won't mix as quickly, and will remain heated longer, leading to
additional evaporation. Smaller receiving streams are also more likely to be affected by
thermal discharges from the perspective of 316(a), which requires that the discharge not
affect the "balanced indigenous population."
Dry cooling and hybrid (wet/dry) cooling are available technologies that reduce
evaporative losses. Dry cooling systems require virtually no water withdrawals and
hybrid systems consume about 15 percent less water through evaporation. EPA's record
shows these systems for reducing evaporative losses have been available and
demonstrated for over 30 years.
While EPA did not attempt to identify or quantify the meteorological effects, the water
vapor in the evaporative plumes does not simply disappear; it will be incorporated into
the atmosphere and may return to the original watershed in the form of precipitation.
Finally, cooling water withdrawals are a very small component of consumptive uses
nationwide. As noted in EPA's Closed-cycle Cooling Systems for Steam-electric Power
Plants: A State-of-the-art Manual (DCN 10-6845F), consumptive water uses by the steam
electric sector was 1.2 percent of consumptive uses nationwide in 1975; agriculture was
85 percent, drinking water was 7 percent and mining was 7 percent. The Nuclear Energy
Institute presented similar data, noting that a closed-cycle power plant typically consumes
23 gallons of water per day per household served with electricity, while the same average
household uses 94 gallons per day for domestic uses.
10.8 Thermal Effluent
EPA notes that Section 316(a) of the CWA provides EPA the authority to deal with
thermal effects and that technologies used to meet 316(b) standards may have impacts
and/or benefits for meeting 316(a) requirements. Given the lack of specific data on the
impact of thermal effects, EPA did not conduct a formal analysis or quantify the impacts
of thermal effluent discharges, although the conversion to cooling towers clearly presents
a significant reduction in the discharge of heat, a regulated pollutant. EPA did conduct
an overview of thermal discharge data for a sampling of electric generator facilities in the
Permit Compliance System, but excluded data from facilities that already use closed
cycle cooling. EPA has calculated that mechanical draft evaporative cooling towers are
an effective technology for reducing the volume of surface water withdrawn for cooling
and can reduce once-through intake flows by 93 percent to 99 percent depending on
operating conditions such as the temperature rise and the cycles of concentration.
10-11
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Chapter 10: Non-water Quality Impacts § 316(b) Existing Facilities Proposed Rule - TDD
10.9 References
California Ocean Protection Council (OPC). 2008. California's Coastal Power Plants:
Alternative Cooling System Analysis. Available at
http://www.opc.ca.gov/webmaster/ftp/project_pages/OTC/engineering%20studv/
CA_Power_Plant_Analysis_Complete.pdf.
California State Water Resources Control Board and California Environmental Protection
Agency (SWRCB). 2010. Water Quality Control Policy on the Use of Coastal and
Estuarine Waters for Power Plant Cooling Final Substitute Environmental
Document. Available at
http://www.swrcb.ca.gov/water_issues/programs/npdes/docs/cwa316may2010/sed
final.pdf.
Electric Power Research Institute (EPRI). 2002. Water & Sustainability (Volume 3):
U.S. Water Consumption for Power Production—The Next Half Century. EPRI,
Palo Alto, CA: 2002. 1006786.
Environmental Protection Agency (EPA). 2010a. Sulfur Dioxide. Available at
http://www.epa.gov/air/sulfurdioxide/.
Environmental Protection Agency. 201 Ob. Nitrogen Dioxide Information. Available at
http://www.epa.gov/oaqps001/greenbk/nindex.html.
Environmental Protection Agency. 2010c. Nitrogen Dioxide. Available at
http://www.epa.gov/airquality/nitrogenoxides/.
Environmental Protection Agency. 2010d. Particulate Matter. Available at
http://www.epa.gov/air/particlepollution/.
Environmental Protection Agency. 1978. Protective Noise Levels. EPA 550/9-79-100
November 1978.
Lavalee, Tim. 2008. Personal communication with Kelly Meadows, Tetra Tech.
September 16, 2008.
New York Department of Environmental Conservation (NYDEC). 2000. Assessing and
Mitigating Noise Impacts. Available at
http://www.dec.ny.gov/docs/permits ej operations_pdf/noise2000.pdf.
Nuclear Energy Institute (NEI). 2010. Water Use and Nuclear Power Plants. May 2010.
Available at http://www.nei.org/filefolder/Water_Use_Fact_Sheet_0510_1 .pdf
Nuclear Regulatory Commission (NRC). 1996. Generic Environmental Impact Statement
for License Renewal of Nuclear Plants. NUREG-1437 Vol. 1.
http://www.nrc.gov/docs/nuregs/staff/srl437/Vl/srl437vl.html#_l_128
SPX Cooling Technologies (SPX). 2009. Cooling Tower Fundamentals. Ed. John
Hensley. SPX Cooling Technologies, Overland Park, Kansas. Available at
http://spxcooling.com/pdf/Cooling-Tower-Fundamentals.pdf.
10-12
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§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 10: Appendix
Appendix to Chapter 10: Non-water Quality Impacts
10A.O Air Emissions Data for Option 2
EPA assumed that the 136 power plants withdrawing 125 MGD or more for which air
emissions data is available would retrofit to recirculating wet cooling towers (not
including those facilities already employing cooling towers). This table represents
facility-specific increases; the data are based on the estimated energy penalty for each
facility, the facility's historic average electricity generation level, and its average historic
emission rates.
Unit
1
2
3
4
5
6
1
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Total increase in
Annual CC>2
(tons)
47,062.09
25,758.85
309.09
17,646.79
-
14,022.39
26,508.32
37,197.49
17,547.14
5,114.76
3,427.09
45,620.40
127.92
9,982.55
5,883.26
214,619.09
16,853.90
24,876.82
41,790.45
38,635.50
15,647.31
112,328.50
2,957.93
41,808.74
9,977.82
15,885.15
89,591.31
41,438.63
5,627.19
148.85
6,955.23
51,350.22
6,312.31
551.25
98,796.63
128,643.03
104,088.03
Total
increase in
Annual SC>2
(tons)
462.89
182.78
0.07
174.67
-
72.49
0.15
66.09
120.60
0.27
44.84
181.72
0.16
8.94
1.17
41.72
232.41
106.21
349.91
551.81
256.38
273.52
0.32
542.94
2.22
11.59
106.55
107.78
0.03
0.18
15.62
238.61
0.03
0.03
209.09
664.68
451.36
Total
increase in
Annual NOX
(tons)
103.63
90.66
1.23
47.89
-
38.80
7.26
92.44
33.08
13.03
7.85
83.39
0.20
15.78
4.81
64.54
50.84
40.74
163.05
149.18
55.88
51.91
1.53
97.13
4.40
25.09
82.10
66.59
3.91
0.23
12.49
128.75
1.20
0.47
276.70
209.76
456.50
Total
increase in
Annual Hg
(Ibs)
2.71
1.93
0.70
0.52
1.12
1.38
0.17
0.92
0.20
1.21
4.89
0.58
14.10
1.92
3.80
2.41
1.25
2.31
5.53
2.28
Total increase
in Annual
PM2.5
(tons)
21.68
28.65
12.49
5.10
0.04
8.29
2.26
9.87
-
1.08
27.71
-
-
-
-
17.41
3.88
5.96
10.84
21.15
33.78
2.30
10.45
6.75
0.32
-
0.93
11.88
0.25
0.22
13.93
24.91
Total
increase in
AnnualPMIO
(tons)
26.24
32.96
15.62
6.39
0.04
23.12
2.26
5.49
13.32
-
1.36
28.22
-
-
-
-
19.21
4.42
7.86
12.31
27.82
38.56
2.37
17.70
8.98
0.32
-
1.22
16.62
0.25
0.22
18.60
30.44
3.02
10A-1
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Chapter 10: Appendix
§ 316(b) Existing Facilities Proposed Rule - TDD
Unit
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
Total increase in
Annual CO2
(tons)
3,316.93
29,456.81
125,430.47
24,843.22
100,889.85
28,645.06
46,639.02
94,162.18
43,849.02
215,723.35
26,284.78
83,873.34
64,350.01
149,318.10
54,419.06
-
73,506.91
33,331.51
14,929.32
13,141.93
71,845.14
465,996.64
126,653.35
112,406.67
84,840.09
120,257.80
109,150.28
31.63
86,409.28
29,407.30
73,475.45
172,555.52
82,741.51
154,976.34
47,713.04
151,309.02
21,922.20
11,196.38
41,876.76
14,759.60
55,712.41
179,421.18
212,738.66
189,651.05
65,809.54
36,324.07
15,718.64
191,789.22
20,216.39
239,320.63
13,326.31
1.64
232,197.58
Total
increase in
Annual SO2
(tons)
0.04
152.77
1,212.29
122.04
387.50
571.47
353.01
558.07
179.11
1,736.65
0.17
398.21
445.24
697.85
13.21
-
461.34
209.74
0.09
4.91
501.61
1,351.75
126,653.35
2,034.33
135.58
169.46
495.24
-
396.89
50.62
589.60
1,356.09
996.05
508.53
106.61
972.71
0.11
1.80
0.23
23.50
149.93
1,251.65
420.00
1,470.08
378.27
0.30
0.04
857.49
0.11
646.69
1.13
-
2,787.33
Total
increase in
Annual NOX
(tons)
3.72
57.76
180.61
139.03
117.70
55.81
63.12
171.88
75.57
475.96
8.25
129.19
143.20
287.80
32.41
-
129.32
100.16
6.66
14.04
93.99
557.28
208.98
190.48
277.76
442.70
326.70
0.01
118.42
36.82
156.50
240.19
104.63
243.02
71.76
123.17
26.27
22.64
11.94
18.14
57.41
234.68
172.87
333.25
156.37
3.55
0.87
448.65
15.36
278.35
19.61
-
415.09
Total
increase in
Annual Hg
(Ibs)
0.87
0.69
5.34
1.51
5.06
0.69
13.13
3.63
2.66
4.18
-
4.77
2.07
3.47
8.93
11.26
4.89
2.39
6.48
4.34
4.77
9.37
9.32
9.37
6.75
8.64
33.94
5.63
6.89
7.72
8.33
Total increase
in Annual
PM2.5
(tons)
0.32
4.31
65.05
3.95
36.94
25.13
4.56
6.68
5.78
42.76
-
15.54
18.85
22.37
1.33
25.35
11.34
1.33
1.54
25.92
53.92
109.14
88.06
19.21
7.14
0.04
17.30
7.25
16.59
104.11
33.03
16.33
8.22
8.33
2.51
1.83
1.40
1.08
8.36
59.34
37.44
56.97
-
3.91
16.62
1.97
13.14
0.86
0.39
82.10
Total
increase in
AnnualPMIO
(tons)
0.32
5.03
71.23
3.95
62.39
26.31
6.14
15.33
10.05
46.92
-
30.98
23.37
23.30
1.33
29.76
14.04
1.33
1.54
29.26
72.16
109.21
91.90
8.69
28.00
7.65
0.04
17.91
7.25
21.11
150.21
38.34
21.76
10.45
8.33
2.51
1.83
1.40
1.26
11.74
66.27
46.02
58.66
-
3.91
31.56
1.97
22.08
0.86
1.22
91.51
10A-2
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 10: Appendix
Unit
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
TOTAL
Total increase in
Annual CO2
(tons)
247,340.42
133,651.85
181,036.27
3,492.64
318,582.91
323,849.40
193,434.16
150,672.13
40,719.17
223,448.67
8,555.80
299,311.78
176,410.50
74,228.78
188,729.21
10,802.33
72,148.92
141,882.58
17,576.18
430,167.67
303,341.43
11,130.96
492,439.33
298,837.98
133,838.18
318,262.91
552,928.93
137,532.97
280,145.79
361,319.89
279,371.93
620,697.97
319,700.75
510,476.19
49,502.38
102,624.92
934,864.48
395,263.14
2,957.39
17,817.23
236,556.23
627,946.34
650,275.69
743,242.36
606,115.85
154,739.88
18,360,926.72
Total
increase in
Annual SO2
(tons)
658.21
1,528.41
1,093.83
0.32
932.07
3,755.21
2,397.29
79.21
84.37
1,630.73
0.04
755.68
503.87
355.64
437.10
0.05
115.46
860.39
0.09
1,048.36
3,017.74
0.06
1,926.14
2,685.20
1,154.35
1,397.99
3,825.75
748.11
1,444.56
408.45
1,167.42
1,992.54
2,680.25
3,475.57
0.25
1.38
2,975.95
1,234.25
0.01
0.09
463.21
2,861.15
3,959.99
1,985.06
627.29
1,181.66
214,741.34
Total
increase in
Annual NOX
(tons)
521.08
413.44
345.40
2.92
198.31
500.13
323.89
25.52
65.79
298.85
1.20
181.28
247.99
224.72
166.01
0.79
168.23
315.13
4.39
245.26
464.77
13.98
691.02
437.93
265.87
586.15
903.42
317.88
393.03
857.18
382.51
342.07
812.09
733.05
13.41
251.19
651.78
651.74
3.52
29.71
166.69
507.50
1,270.78
178.47
975.98
356.45
26,591.23
Total
increase in
Annual Hg
(Ibs)
13.43
9.32
8.97
21.10
20.83
7.39
9.66
12.00
9.53
27.27
1.89
5.79
27.63
36.96
18.58
23.38
4.79
14.88
22.55
7.66
5.65
9.55
32.76
18.87
19.32
56.86
16.94
10.06
77.30
45.12
20.97
9.47
873.51
Total increase
in Annual
PM2.5
(tons)
22.80
74.03
3.95
0.14
28.43
168.05
100.77
7.04
6.00
54.21
10.77
22.33
16.48
17.77
3.91
19.96
65.19
1.69
44.05
98.33
4.38
90.54
75.71
77.87
103.57
232.81
57.19
62.47
53.17
35.43
25.49
177.96
5.89
14.25
90.00
88.53
-
1.08
11.99
105.22
101.06
94.78
3,653.08
Total
increase in
AnnualPMIO
(tons)
29.51
74.82
7.83
0.18
34.54
219.49
108.27
7.43
6.79
63.36
10.95
27.97
22.55
28.86
3.95
38.41
87.74
1.72
80.74
117.18
4.38
107.48
80.85
80.20
115.13
258.30
58.05
91.04
60.81
62.29
36.94
205.31
5.89
14.25
102.28
113.80
-
1.08
12.28
171.57
108.63
129.49
4,495.65
10A-3
-------
Chapter 10: Appendix
§ 316(b) Existing Facilities Proposed Rule - TDD
10A.1 Air Emissions Data for Option 3
EPA assumed that all 167 power plants for which data is readily available would retrofit
to recirculating wet cooling towers. This table represents facility-specific increases; the
data are based on the estimated energy penalty for each facility, the facility's historic
average electricity generation level, and its average historic emission rates.
Unit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Total increase
in Annual CO2
(tons)
9,603.30
-
2,188.80
-
289,758.55
91.61
-
-
5,488.98
121,821.75
20,355.14
28,787.97
1,496.18
5,718.97
-
39,262.67
321.24
15,690.00
15,871.58
11,470.36
3,891.51
2,842.32
16,719.07
277.81
25,010.72
24,760.44
39,923.88
-
6,312.31
2,136.46
2,974.80
47,062.09
25,758.85
309.09
17,646.79
-
14,022.39
26,508.32
37,197.49
17,547.14
5,114.76
3,427.09
Total
increase in
Annual SO2
(tons)
89.47
-
30.98
-
936.94
-
-
-
0.05
382.08
23.25
397.72
0.41
0.03
-
0.60
0.01
110.42
333.43
235.69
16.56
14.14
97.23
0.01
156.42
85.60
191.76
0.01
0.03
30.26
7.91
462.89
182.78
0.07
174.67
-
72.49
0.15
66.09
120.60
0.27
44.84
Total
increase in
Annual NOX
(tons)
41.47
37.27
9.56
-
210.06
0.02
25.95
23.40
1.45
495.89
26.52
53.05
2.84
4.17
0.11
2.43
0.52
29.83
39.55
25.22
7.37
4.19
56.40
0.45
52.03
43.78
85.00
33.98
1.20
6.25
4.96
103.63
90.66
1.23
47.89
-
38.80
7.26
92.44
33.08
13.03
7.85
Total
increase in
Annual Hg
(Ibs)
8.21
2.63
12.83
2.32
5.06
3.33
0.62
1.85
0.23
0.71
1.69
0.63
0.71
1.55
1.80
0.76
2.71
1.93
0.70
0.52
1.12
1.38
Total increase
in Annual
PM2.5
(tons)
-
-
0.07
18.92
-
-
-
0.86
14.93
1.01
30.98
-
19.49
-
-
-
-
19.57
0.65
-
-
3.23
8.26
11.34
-
0.04
-
0.25
21.68
28.65
12.49
5.10
0.04
8.29
2.26
9.87
-
1.08
Total
increase in
Annual PM10
(tons)
0.04
-
0.25
0.22
22.08
-
-
-
0.86
14.93
1.33
33.03
-
22.04
-
-
-
-
20.10
0.65
-
-
5.85
14.75
14.11
-
0.04
-
0.32
26.24
32.96
15.62
6.39
0.04
23.12
2.26
5.49
13.32
-
1.36
10A-4
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§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 10: Appendix
Unit
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
Total increase
in Annual CO2
(tons)
45,620.40
127.92
9,982.55
5,883.26
214,619.09
16,853.90
24,876.82
41,790.45
38,635.50
15,647.31
112,328.50
2,957.93
41,808.74
9,977.82
15,885.15
89,591.31
41,438.63
5,627.19
148.85
6,955.23
51,350.22
6,312.31
551.25
98,796.63
128,643.03
104,088.03
3,316.93
29,456.81
125,430.47
24,843.22
100,889.85
28,645.06
46,639.02
94,162.18
43,849.02
215,723.35
26,284.78
83,873.34
64,350.01
149,318.10
54,419.06
-
73,506.91
33,331.51
14,929.32
13,141.93
71,845.14
465,996.64
126,653.35
112,406.67
Total
increase in
Annual SO2
(tons)
181.72
0.16
8.94
1.17
41.72
232.41
106.21
349.91
551.81
256.38
273.52
0.32
542.94
2.22
11.59
106.55
107.78
0.03
0.18
15.62
238.61
0.03
0.03
209.09
664.68
451.36
0.04
152.77
1,212.29
122.04
387.50
571.47
353.01
558.07
179.11
1,736.65
0.17
398.21
445.24
697.85
13.21
-
461.34
209.74
0.09
4.91
501.61
1,351.75
126,653.35
2,034.33
Total
increase in
Annual NOX
(tons)
83.39
0.20
15.78
4.81
64.54
50.84
40.74
163.05
149.18
55.88
51.91
1.53
97.13
4.40
25.09
82.10
66.59
3.91
0.23
12.49
128.75
1.20
0.47
276.70
209.76
456.50
3.72
57.76
180.61
139.03
117.70
55.81
63.12
171.88
75.57
475.96
8.25
129.19
143.20
287.80
32.41
-
129.32
100.16
6.66
14.04
93.99
557.28
208.98
190.48
Total
increase in
Annual Hg
(Ibs)
0.17
0.92
0.20
1.21
4.89
0.58
14.10
1.92
3.80
2.41
1.25
2.31
5.53
2.28
0.87
0.69
5.34
1.51
5.06
0.69
13.13
3.63
2.66
4.18
-
4.77
2.07
3.47
8.93
11.26
4.89
Total increase
in Annual
PM2.5
(tons)
27.71
-
-
-
-
17.41
3.88
5.96
10.84
21.15
33.78
2.30
10.45
6.75
0.32
-
0.93
11.88
0.25
0.22
13.93
24.91
0.32
4.31
65.05
3.95
36.94
25.13
4.56
6.68
5.78
42.76
-
15.54
18.85
22.37
1.33
25.35
11.34
1.33
1.54
25.92
53.92
109.14
88.06
Total
increase in
Annual PM10
(tons)
28.22
-
-
-
-
19.21
4.42
7.86
12.31
27.82
38.56
2.37
17.70
8.98
0.32
-
1.22
16.62
0.25
0.22
18.60
30.44
3.02
0.32
5.03
71.23
3.95
62.39
26.31
6.14
15.33
10.05
46.92
-
30.98
23.37
23.30
1.33
29.76
14.04
1.33
1.54
29.26
72.16
109.21
91.90
10A-5
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Chapter 10: Appendix
§ 316(b) Existing Facilities Proposed Rule - TDD
Unit
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
Total increase
in Annual CO2
(tons)
84,840.09
120,257.80
109,150.28
31.63
86,409.28
29,407.30
73,475.45
172,555.52
82,741.51
154,976.34
47,713.04
151,309.02
21,922.20
11,196.38
41,876.76
14,759.60
55,712.41
179,421.18
212,738.66
189,651.05
65,809.54
36,324.07
15,718.64
191,789.22
20,216.39
239,320.63
13,326.31
1.64
232,197.58
247,340.42
133,651.85
181,036.27
3,492.64
318,582.91
323,849.40
193,434.16
150,672.13
40,719.17
223,448.67
8,555.80
299,311.78
176,410.50
74,228.78
188,729.21
10,802.33
72,148.92
141,882.58
17,576.18
430,167.67
303,341.43
Total
increase in
Annual SO2
(tons)
135.58
169.46
495.24
-
396.89
50.62
589.60
1,356.09
996.05
508.53
106.61
972.71
0.11
1.80
0.23
23.50
149.93
1,251.65
420.00
1,470.08
378.27
0.30
0.04
857.49
0.11
646.69
1.13
-
2,787.33
658.21
1,528.41
1,093.83
0.32
932.07
3,755.21
2,397.29
79.21
84.37
1,630.73
0.04
755.68
503.87
355.64
437.10
0.05
115.46
860.39
0.09
1,048.36
3,017.74
Total
increase in
Annual NOX
(tons)
277.76
442.70
326.70
0.01
118.42
36.82
156.50
240.19
104.63
243.02
71.76
123.17
26.27
22.64
11.94
18.14
57.41
234.68
172.87
333.25
156.37
3.55
0.87
448.65
15.36
278.35
19.61
-
415.09
521.08
413.44
345.40
2.92
198.31
500.13
323.89
25.52
65.79
298.85
1.20
181.28
247.99
224.72
166.01
0.79
168.23
315.13
4.39
245.26
464.77
Total
increase in
Annual Hg
(Ibs)
2.39
6.48
4.34
4.77
9.37
9.32
9.37
6.75
8.64
33.94
5.63
6.89
7.72
8.33
13.43
9.32
8.97
21.10
20.83
7.39
9.66
12.00
9.53
27.27
1.89
5.79
27.63
36.96
Total increase
in Annual
PM2.5
(tons)
19.21
7.14
0.04
17.30
7.25
16.59
104.11
33.03
16.33
8.22
8.33
2.51
1.83
1.40
1.08
8.36
59.34
37.44
56.97
-
3.91
16.62
1.97
13.14
0.86
0.39
82.10
22.80
74.03
3.95
0.14
28.43
168.05
100.77
7.04
6.00
54.21
10.77
22.33
16.48
17.77
3.91
19.96
65.19
1.69
44.05
98.33
Total
increase in
Annual PM10
(tons)
8.69
28.00
7.65
0.04
17.91
7.25
21.11
150.21
38.34
21.76
10.45
8.33
2.51
1.83
1.40
1.26
11.74
66.27
46.02
58.66
-
3.91
31.56
1.97
22.08
0.86
1.22
91.51
29.51
74.82
7.83
0.18
34.54
219.49
108.27
7.43
6.79
63.36
10.95
27.97
22.55
28.86
3.95
38.41
87.74
1.72
80.74
117.18
10A-6
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§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 10: Appendix
Unit
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
TOTAL
Total increase
in Annual CO2
(tons)
11,130.96
492,439.33
298,837.98
133,838.18
318,262.91
552,928.93
137,532.97
280,145.79
361,319.89
279,371.93
620,697.97
319,700.75
510,476.19
49,502.38
102,624.92
934,864.48
395,263.14
2,957.39
17,817.23
236,556.23
627,946.34
650,275.69
743,242.36
606,115.85
154,739.88
19,053,703.14
Total
increase in
Annual SO2
(tons)
0.06
1,926.14
2,685.20
1,154.35
1,397.99
3,825.75
748.11
1,444.56
408.45
1,167.42
1,992.54
2,680.25
3,475.57
0.25
1.38
2,975.95
1,234.25
0.01
0.09
463.21
2,861.15
3,959.99
1,985.06
627.29
1,181.66
217,882.36
Total
increase in
Annual NOX
(tons)
13.98
691.02
437.93
265.87
586.15
903.42
317.88
393.03
857.18
382.51
342.07
812.09
733.05
13.41
251.19
651.78
651.74
3.52
29.71
166.69
507.50
1,270.78
178.47
975.98
356.45
27,916.17
Total
increase in
Annual Hg
(Ibs)
18.58
23.38
4.79
14.88
22.55
7.66
5.65
9.55
32.76
18.87
19.32
56.86
16.94
10.06
77.30
45.12
20.97
9.47
918.43
Total increase
in Annual
PM2.5
(tons)
4.38
90.54
75.71
77.87
103.57
232.81
57.19
62.47
53.17
35.43
25.49
177.96
5.89
14.25
90.00
88.53
-
1.08
11.99
105.22
101.06
94.78
3,782.68
Total
increase in
Annual PM10
(tons)
4.38
107.48
80.85
80.20
115.13
258.30
58.05
91.04
60.81
62.29
36.94
205.31
5.89
14.25
102.28
113.80
-
1.08
12.28
171.57
108.63
129.49
4,646.25
10A.2 GIS Analyses of Expected Pollutants from Potentially
Affected Facilities
EPA created maps with the locations of all Phase II facilities (excluding manufacturers)
overlaid with maps of non-attainment areas for the various criteria air pollutants:
• Carbon monoxide (CO)
• Lead (Pb)
• Parti culate matter (PM2.5)
• Parti culate matter (PM10)
• Ozone
• Sulphur dioxide (802)
10A-7
-------
COi Nonattainment Areas
A
Legend
• Plant_Locations
CO Nonattainment counties
V 1
I
-o
13
1
x
Source: U.S. EPA Office of Air and Radiation, AQS Database.
cm
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to
R1
-o
I
Q_
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-------
Pb Nonattainment Areas
A
Legend
• Plant_Locations
I Lead Nonattainment counties
cm
CO
%
to
-n
R
-a
3
•g
I
TO
I
C7
C7
Source: US EPA Office of Air and Radiation. AQS Database.
g"
-o
I
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O
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-------
PM2.5 Nonattainment Areas
A
Legend
• Plant_Locations
| | PM2.5_Nonattainment_counties Source: U.S. EPA Office of Air and Radiation, AQS Database.
V 1
I
-o
13
g,
x
an
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g
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PM10 Nonattainment Areas
cm
CO
A
Legend
• Plant_Locations
PM10 Nonattainment counties Source: U.S. EPA Office of Air and Radiation. AQS Database.
%
to
~n
R
-o
3
•g
I
TO
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-o
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i
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-------
Ozone Nonattainment Areas
A
Legend
• Plant_Locations
"1 OzoneShr Nonattainment counties Source: U.S. EPA Office of Air and Radiation, AQS Database.
V 1
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-o
13
g,
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-o
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SOi Nonattainment Areas
an
CO
A
Legend
• Plant_Locations
n SulfurDioxide Nonattainment counties Source: U.S EPA Office of Air and Radiation, AQS Database.
%
to
-n
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3
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-------
-------
Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
Chapter 11: Impingement Mortality Limitations and
Entrainment Data
11.0 Introduction
This section describes the data selection and statistical methodology used by EPA in
calculating the proposed impingement mortality limitations and evaluating the
entrainment data for a potential design standard. As described in this section, the
proposed limitations account for variation in technology performance. Chapter 6
describes the technologies in further detail.
Section 11.1 provides an overview of the available impingement and entrainment data
and EPA's selection criteria. Section 11.2 describes the data and locations used as the
basis for the impingement mortality limitations, statistical methodology used to calculate
the limitations, and compliance monitoring. Section 11.3 describes the entrainment data
and evaluations.
11.1 Overview of Data Selection
In its evaluations of impingement and entrainment, EPA considered data from research
studies, technology evaluations, and facility 316(b) demonstrations that spanned the past
40 years. While many of the documents had been collected during the Phase II
rulemaking, EPA reviewed documents that were published up to 2008. The primary
objective of the document review was to identify relevant information about the
performance of different technologies in minimizing impingement and entrainment of
aquatic organisms.
This chapter uses the term "study" to refer to the collection of performance data at a
single facility (or location) under a given set of testing conditions. For example, different
studies may correspond to different screen mesh sizes or approach velocities that were
tested at the same facility. A document can report performance data for one or more
studies at one or more facilities. EPA focused on studies that provided specific
performance metrics such as percent mortality. It also obtained information about the
facilities themselves, including operating conditions, species of organisms, and time
periods when the studies were conducted. EPA extracted the information into a master
database (see DCN 10-5400 for a version in Excel format). Appendix A lists the 178
documents that EPA reviewed, notes those data that were selected for the calculations
described in this section, and describes the reasons for excluding certain documents or
studies from consideration. Appendix B provides results from a summary and statistical
analysis of impingement and entrainment data extracted from these documents.
11.1.1 Data Acceptance Criteria
For different types of analyses for the proposal, EPA specified criteria that were relevant
for the particular analysis. As a consequence, the same data were not used consistently
11-1
-------
Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
throughout EPA's analyses. EPA considers this approach to be reasonable because it
results in the best selection of data that correspond to the objective of each analysis. In
determining whether data were acceptable for the impingement and entrainment analyses
described in this chapter, EPA used four general criteria. Sections 11.2 and 11.3 describe
additional criteria specific to impingement and entrainment. The four general criteria are:
1. The data must provide information about one of the candidate technologies shown in
Exhibit 11-1. (Chapter 6 provides EPA's review of candidate technologies for
impingement and entrainment.)
2. The data must be a quantitative measure that relates to either impingement mortality
or entrainment of some life form of aquatic organisms within cooling water intake
structures under the given technology. This criterion requires documents to report
either or both:
• Impingement mortality as an absolute number or a percentage of impinged fish
that were killed.
• Entrainment as the numbers of organisms or density per unit volume of water. In
addition, the study must have number of organisms (or density) for paired
samples: 1) one sample collected from water that had not yet passed through the
technology; and 2) another sample collected from water that has passed through
the technology. In this manner, EPA could evaluate the percent change in
entrainment associated with the technology.
3. The data must reflect technology performance that is representative of conditions that
may exist under actual facility operations. As a consequence of this criterion, EPA:
• Included data from studies conducted on existing structures at facilities;
• Included data from field tests conducted near intake locations (e.g., from a test
barge). Before full-scale installation, facilities often test the suitability of
technologies in conditions that they consider to mimic (or represent) typical
facility conditions.
• Excluded data from tests performed under controlled laboratory conditions.
These studies are described in the memo "316b: Laboratory Test Data Related to
Entrainment" (Battelle, 2008). In contrast to the facility and field studies that
generally are designed to represent normal conditions and operations, the
laboratory studies generally studied how impingement and entrainment were
affected by varying different components of the technology. In such studies, the
laboratories sometimes operate the technologies with the intention of increasing
impingement or entrainment occurrences. As a consequence, data from these
studies are not representative of the performance expected at the facilities.
4. When data were used in deriving proposed limitations (e.g., for impingement
mortality), the reported values must be actual measurements, rather than estimates.
For entrainment, both actual and estimated data values were deemed acceptable for
the evaluations.
11-2
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
Exhibit 11-1. Candidate Technologies Reviewed in the Documents
BTA technology
Alternate terms
Impingement technologies
Cylindrical wedgewire (coarse)
Fine mesh cylindrical wedgewire
Ristroph (modified) traveling screen with fish return
Offshore intake with velocity cap
Barrier net
Fine mesh traveling screen with fish return
Closed-cycle cooling system
Fixed screens — coarse mesh
Fixed screens — fine mesh
Traveling screen — coarse mesh
Offshore location with velocity cap
Barriers
Traveling screen — fine mesh
Reduced intake flows — cooling tower
Entrainment technologies
Fine mesh cylindrical wedgewire
Fine mesh Ristroph (modified) traveling screen with
fish return
Offshore intake with velocity cap
Fine mesh traveling screen with fish return
Aquatic filter barrier
Closed-cycle cooling system
Fixed screens — fine mesh
Traveling screen — fine mesh
Offshore location with velocity cap
Traveling screen — fine mesh
Barriers
Reduced intake flows — cooling tower
Many documents did not have performance data that met these four general criteria, and
therefore, were eliminated early in the review process. Of those performance data that
were entered into the database, the data appear to fall within two primary classifications:
• Data that originate from simple observational studies. These studies provide
impingement/entrainment data at one or more points in time, when the given
technology is in operation. Depending on how a particular document reports
study outcomes, these data may represent counts or percentages, such as percent
mortality, percent survival (or other positive outcome, such as retention or
diversion), percent biomass, or percent injury. Mortality and/or survival data
were reported most often, while injury data were reported rarely.
• Paired data sets that correspond to either "before/after implementation" or
"treatment/control," which allow for comparisons to be made to some baseline
condition when evaluating technology performance at a given location. The
paired data sets result in either counts or percentages of organisms being reported
under both conditions (e.g., treatment and control, before implementation and
after implementation).
11.1.2 Future Data Reviews
For the final rule, if EPA receives new data, EPA may revise the calculated limits.
11-3
-------
Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
11.2 Proposed Impingement Mortality Limitations
EPA is proposing numerical limitations that will restrict mortality offish resulting from
impingement. This section describes impingement mortality data, the selection of facilities
used as a basis of the proposed limitations, the calculations, and compliance monitoring.
11.2.1 Impingement Mortality Percentage Data
After applying the general acceptance criteria described in Section 11.1, EPA extracted
impingement mortality data where they were available in the 178 documents which EPA
reviewed (Appendix A) and used these data to characterize impingement mortality
percentages. The extracted impingement data were reported in several different ways:
• Percentage of impinged fish that were killed. EPA used these values as reported.
• Percentage of impinged fish that survived. To obtain percent mortality, EPA
subtracted this percentage from 100 percent.
• Total number of impinged fish, along with numbers of impinged fish that either
survived or were killed. EPA summed each of these measures across all reported
species, life stages, etc., and calculated the impingement mortality percentage as:
, total number killed , „„
impingement mortality percentage = x 100
total number impinged
• Impingement survival counts and numbers of impinged fish. EPA first calculated
the total of all reported species, life stages, etc., and then calculated an
impingement mortality percentage as:
impingement mortality percentage =
1-
total number survived
total number impinged
xlOO
As a result of applying other criteria described below, studies with the first two data types
were excluded for reasons other than the type of data that they reported. Consequently,
the proposed limitations were based upon studies that reported the last two of the four
data types. For the final rule, EPA would consider data from any of the four data types.
11.2.2 Additional Criteria Used to Select Data and Facilities as the
Basis for Impingement Mortality Limitations
After extracting the impingement data, EPA applied several additional criteria beyond
those described in Section 11.1 to select data as the basis of the proposed limitations.
The additional criteria are:
• The facility must have employed the selected BTA technology basis for
impingement: modified traveling screens. As described in Chapter 6, this
technology includes, at a minimum, modified traveling screens with either
Ristroph or post-Fletcher features including a dedicated fish handling and return.
At least six facilities were excluded, in part, as a result of this criterion.
11-4
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
• The study must have measured total mortality from the time of impingement to no
later than 48 hours following impingement. As a consequence of this criterion,
EPA excluded:
o Studies that reported only instantaneous mortality ("zero holding times").
Such counts may be understated because they only measure immediate deaths
and not those organisms that were mortally harmed as a result of
impingement. They also might reflect already injured, nearly dead, or already
dead fish ("naturally moribund") that were impinged by the screen.
o Data associated with mortality that occurred in excess of 48 hours following
impingement. Such counts may be overstated because these longer holding
times may cause mortality for reasons not directly reflective of technology
performance, such as conditions that do not adequately reflect the organisms'
natural habitats.
• The study must have evaluated all species that are typical for that location.
Because certain species may be of particular concern, some studies focus on the
performance of the technology for them rather than all species likely to impinge
on the screens. As a consequence of this criterion, EPA excluded data from two
studies performed at the Salem Generating Station on the Delaware River. The
1995 study only monitored weakfish (Ronafalvy et al., 2000) and the 1997-8
study focused primarily on weakfish (EPRI, 2007). According to plant personnel,
weakfish is not predominant at that location, and thus, EPA has excluded the data.
As a consequence of these additional criteria (i.e., beyond Section 11.2.2), Exhibit 11-2
identifies the facilities whose data were excluded from the basis of the impingement
mortality limitations. Appendix A contains additional detail on why impingement data
from certain documents were excluded from consideration.
Exhibit 11-2. List of Excluded Facilities with Impingement Data
Facility Name
Barney Davis
Big Bend
Bowline Point
Brayton Point
Brunswick
Danskammer Point
Indian Point
JEA Northside
Mystic
Potomac River
Prairie Island
Salem
Somerset
Surry
Reasons for Excluding
Impingement Studies from Facility
Holding Time = 0, Did not have modified Traveling Screen technology
Holding Time = 0; Did not have modified Traveling Screen technology
Holding Time = 0; Did not have modified Traveling Screen technology
Holding Time = 0; Did not have modified Traveling Screen technology
Holding Time = 0; Did not have modified Traveling Screen technology
Holding Time > 48h; Holding Time = 0
Holding Time = 0; Holding Time > 48 hours
Holding Time = 0
Holding Time > 48h
Did not have modified Traveling Screen technology
Holding Time = 0
Species not representative of location
Holding Time > 48h; Holding Time = Zero
Holding Time = 0
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Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
After excluding the facility data identified in Exhibit 11-2, EPA evaluated the remaining
data. Three facilities met all of the criteria, and thus, they form the basis for the proposed
limitations. These facilities are:
1. Arthur Kill Station on Staten Island along the eastern bank of the Arthur Kill tidal
strait (CEC, 1996);
2. Dunkirk Steam Station on Lake Erie (Beak Consultants, Inc., 2000a); and
3. Huntley Steam Station on the Niagara River (Beak Consultants, Inc., 2000b).
Exhibit 11-3 provides a summary of the characteristics and technologies for these three
facilities. Listing 1 of Appendix C lists their data. All of the mortality data were
measured at a latent period of 24 hours.
Exhibit 11-3. Characteristics of Facilities Used As Basis for Impingement Mortality
Limitations
Facility
Name
Arthur
Kill
Dunkirk
Huntley
State
NY
NY
NY
Water
Body
Type
Estuary
Great
Lakes
water
River
Predominant
Species 1
alewife, Atlantic
herring, Atlantic
silverside, bay
anchovy, blueback
herring, weakfish,
crabs
alewife, shiners,
rainbow smelt,
white bass, white
perch, yellow perch
alewife, gizzard
shad, rainbow
smelt, emerald
shiner
Study Period
February 1994
through July
-mac;
Each season
from December
1998 to
November
1999.
January and
October 1999
Generating
Units/
CWISs
Unit 20
Unit 30
Screenhouse
#1, including
Units 1 and 2
Units 67 and
68
Design
Intake
Flow2
87 0
MGD
oo.u
MGD
92.2
MGD
82.8
MGD
Technology
1/8 x 1/2-in mesh
-modified
traveling screen.
1/4 x 1/2-in mesh
modified traveling
screen.
1/8x1/2 inch.
Prototype
modified traveling
screen
1/8x1/2 inch.
Prototype
modified traveling
screen
1 Data for other species may also be available within each study.
2 Derivation of DIP provided in DON 10-6610.
EPRI (2007) describes the sampling events at the three facilities:
• Arthur Kill (pages 2-40 and 2-41): "During the study, the station was operated on
a seasonal schedule from June through September, with a reserve shutdown
period occurring from October through May. . . . Collections were made on a
biweekly to monthly basis from February 1994 through July 1995. The majority
of sampling occurred during the hours of 7 p.m. and 5 a.m., with screens
operating at a rotation speed of 6.1 m/min (20 ft/min). Fish and crabs were
collected by diverting the screenwash water of the individual screens into a
collection tank. Fish and crabs were separated into compatible groups and placed
into holding tanks for 24-hour mortality evaluation. At the end of the holding
period, fish and crabs were categorized by species and condition and counted."
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
• Dunkirk (page 2-16): "The shoreline CWIS at the Dunkirk Steam Station includes
a skimmer wall and two screenhouses. Fish collected for this evaluation were
taken off a prototype Ristroph dual-flow traveling screen in Screenhouse #1. The
screen is 11 ft wide and 29 ft deep and is comprised of "smooth tex" stainless
steel mesh (1/8 by 1A in.) and a fish collection bucket. The screen was run
continuously during sampling. Water from the dual fish/debris return trough was
diverted for 2 hours for each sample. Fish were directed to a collection table and
then were transferred in water to holding tanks where they were held for the 24-hr
latent mortality study. Observations offish condition were made at 2, 4, 8, and 24
hrs after collection."
• Huntley (page 2-21): "Eight-hour samples were collected on five nights from
January 21-25, 1999, and October 24-29, 1999. During sampling, the modified
traveling screens were rotated continuously at 8 ft/min. All fish from Screens #5
and #6 were diverted into a collection table. Sampling was conducted
continuously for up to 2 hours but was shortened when large numbers offish were
impinged. Sampling was interrupted to move fish when necessary. Fish were
removed from the collection table using a brailing device that maintained a
minimum of 4 in. of water and minimized handling stress. Fish were held in large
fiberglass or galvanized steel tanks (ranging in size from 20 to 240 gallons) and
supplied with a continuous supply of water pumped from the forebay. Flow into
the tanks was continuous and provided a moderate circular current. Water in the
holding tanks was exchanged three to five times per hour. No more than 5 g of
fish per liter of water were held in any of the tanks. Fish were separated by size
and predator and prey species were separated. The initial condition of all fish was
assessed prior to being placed into the holding tanks. . . . Only live fish were
transferred to the holding tanks and held for 24 hours to determine latent
mortality."
11.2.3 Calculation of Limitations
EPA applied statistical methods to develop the proposed limitations. Statistical methods
are appropriate for dealing with impingement data because the mortality rates, even in
well-operated systems, are subject to a certain amount of random fluctuation or
uncertainty. Statistics is the science of dealing with uncertainty in a logical and
consistent manner. Statistical methods, therefore, provide a logical and consistent
framework for analyzing a set of impingement data and determining values from the data
that form a reasonable basis for the limitations. In modeling the distribution of
impingement mortality percentage data, EPA selected the beta family of statistical
distributions as the basis for its limitations, because the distributions are continuous and
bounded by 0 and 1. This is equivalent to the range of impingement mortality
percentages between 0 and 100. Appendix D describes this model and alternatives that
EPA may consider in developing the final rule. The following sections provide an
overview of the limitations, the monthly average limitation, the annual average limitation,
and EPA's evaluation of them.
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Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
11.2.3.1 Monthly Average Limitation
-th
The proposed monthly average limitation is based upon the 95 percentile of the beta
distribution modeled on the eight impingement mortality percentages presented in Exhibit
11-4. The use of the 95* percentile represents a need to draw a line at a definite point in
the statistical distributions (a "100th percentile" would not work because it would
represent mortality of all organisms) and a policy judgment about where the line is drawn
to insure that operators work hard to implement practices that represent the appropriate
level of control. In essence, in developing the monthly average limitation proposed for
this rule, EPA has taken into account the reasonable anticipated variability in
impingement mortality that may occur at a well-operated facility. The use of percentiles
in the development of monthly average limitations for the protection of the nation's
waters is a long standing practice that has been upheld by the courts in numerous cases.
The use of the 95th percentile also is consistent with the convention used for other
monthly average limitations (e.g., for pollutant discharges).
The data in Exhibit 11-4 meet EPA's criteria described earlier in the chapter. The data
cover a range of conditions such as seasons, locations, and water bodies. Because the
sampling dates were available, EPA classified data from Dunkirk and Huntley into series
of sampling events that reflected the monitoring frequencies that EPA expects facilities to
use in complying with the monthly average limitation. For the Arthur Kill facility, the
individual sampling event information was not available to EPA, and thus, EPA
considered the data at each unit as if they were from a single sampling event. EPA then
modeled the impingement mortality percentages across the eight events using the beta
distribution. The 95 percentile was estimated to be 30 percent impingement mortality.
Exhibit 11-4. Facilities and Data Used As Basis for Monthly Average Limitation on
Impingement Mortality
Facility
Name
Arthur Kill
Dunkirk
Huntley
Sampling Period
Unit 20, 1994-1995
Unit 30, 1994-1995
12/20/98 to 01 709/99
04/20/99 to 04/28/99
08/1 6/99 to 09/04/99
11/02/99 to 11/1 1/99
01/2 1/99 to 01/25/99
10/24/99 to 10/29/99
Total Number of
Impinged Fish
7,130
3,408
6,775
3,562
1,220
8,928
6,120
3,258
Total Number of
Impinged Fish
that Died
1,366
235
261
435
182
243
561
1,025
Percent
Impingement
Mortality
19.2
6.9
3.9
12.2
14.9
2.7
9.2
31.5
11.2.3.2 Annual Average Limitation
For the proposed annual average limitation, EPA used the statistical expected value
(average) of the beta distribution of the monthly averages presented in Exhibit 11-4. As a
result of applying the statistical methodology, EPA determined that the annual average
limitation was 12 percent impingement mortality. In contrast to the monthly average
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
limitation which provides an allowance for variability, EPA does not believe that any
upward adjustment of the annual average limitation is necessary because compliance is
only determined over a long period of time, that is, during the course of an entire year
during which the facility will have opportunities to modify the technology when
necessary to achieve compliance with the annual average limitation.
11.2.3.3 Statistical Evaluation of Proposed Limitations
As an important step in evaluating the statistical methodology, EPA compared the
proposed limitations to the data used to derive them. In other rulemakings, commenters
have asserted that this comparison step implies that EPA expects occasional
exceedances1 of the limitations. For example, commenters sometimes assert that EPA's
use of the 95th percentile implies that the EPA expects that about 5 percent of the data, or
one month in 20, should fail to meet the monthly average limitation. Such assertions are
incorrect. EPA promulgates limitations that facilities are capable of complying with at all
times by properly operating and maintaining their technologies. Instead, EPA performs
this comparison to ensure that the statistical model is appropriate and that it used
appropriate distributional assumptions for the data used to develop the limitations (i.e.,
whether the curves EPA used provide a reasonable "fit" to the actual data). As a result of
this comparison for the proposed limitations, EPA determined that the distributional
assumptions appear to be appropriate for these data, as explained below:
• For the monthly average limitation based upon the data in the last column of
Exhibit 11-4, all but one value was less than the proposed limitation of 30 percent.
Observing one value in eight that is greater than the limitation is approximately
what is expected from the 95* percentile basis of the statistical methodology.
This impingement mortality of 31.5 percent is marginally greater than the
proposed limitation of 30 percent.
• For the annual average limitation, EPA combined the information from the eight
sampling events in Exhibit 11-4 into the four values shown in Exhibit 11-5 to
better mimic the annual average calculated from monthly averages, as would be
required for compliance reporting. Because Arthur Kill had data for two different
units with slightly different screen specifications, EPA continued to consider the
data from each unit separately. Based upon the data in the last column of
Exhibit 11-5, two of the four values are less than the proposed limitation of
12 percent, which is consistent with the expected value basis of the limitation.
To be consistent with the statistical methodology, EPA would expect about half of
the data to be greater than the limitation, and this is what was observed.
1 Exceedances are values greater than the limitations.
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11-5. Annual Averages of Impingement Mortality Used to Evaluate
Proposed Annual Average Limitation
Facility Name
Arthur Kill, Unit 20
Arthur Kill, Unit 30
Dunkirk
Huntley
Total Number of
Impinged Fish
7,130
3,408
20,485
9,378
Total Number of
Impinged Fish that Died
1,366
235
1,121
1,586
Percent Impingement
Mortality
19.2
6.9
5.5
16.9
11.2.3.4 Biological and Engineering Reviews of Proposed Limitations
In conjunction with the statistical methods, EPA performed engineering and biological
reviews which are yet another important step in verifying that the proposed limitations
are reasonable based upon the design and expected operation of the technologies and the
site conditions. As part of those reviews, EPA examines the range of performance by the
data sets used to calculate the proposed limitations. Some data sets demonstrate the best
technology available. Other data sets may demonstrate the same technology, but not the
best demonstrated design and operating conditions for that technology. For the facilities
corresponding to these datasets, EPA evaluates the degree to which the facility can
upgrade its design, operating, and maintenance conditions to meet the proposed
limitations. If such upgrades are not possible, then the proposed limitations are modified
to reflect the lowest levels of impingement mortality that the technologies can reasonably
be expected to achieve.
• For the monthly average limitation, only one impingement mortality value in
Exhibit 11-4 has a value greater than the proposed limitation of 31 percent. This
larger value occurred in October 1999 at the Huntley facility. With a mortality
percentage of 31.5 percent, it is barely greater than the proposed percentage
limitation of 30 percent. In its engineering review of Huntley's technologies,
EPA determined that Huntley's prototype screen has a slightly smaller mesh size
(1/8 inch by 1/2 inch) than the technologies subject to the proposed limitation.
Smaller screens allow fewer organisms to pass through, retaining more of the
smaller and generally more fragile life-stages, and therefore often demonstrate
increased mortality. The proposed regulation specifies impinged organisms are
those retained by a 3/8-inch mesh; thus the additional organisms would be
excluded from limitation compliance monitoring. Because of the technology
differences, EPA considered whether Huntley's data should be excluded as the
basis of the proposed limitations. As a conservative measure, EPA retained the
data. The Agency reasons that if Huntley can generally achieve the limitations
with the smaller mesh size, then other facilities can achieve the relevant
limitations by adoption of the model technologies which include the larger
mesh size.
• For the annual average limitation, two of the four reported mortality percentages
in Exhibit 11-5 have values greater than the annual average limitation of 12. The
mortality percentages were 16.9 percent from Huntley and 19.2 percent from
Arthur Kill's Unit 20. As discussed for the monthly average limitation, Huntley
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
has a finer mesh size than the proposed technology, and the data were retained in
the dataset as a conservative approach (i.e., excluding the data would have
resulted in a proposed limitation with a lower mortality rate). At Arthur Kill's
Unit 20, the mortality is partially associated with the relatively large numbers of
bay anchovy (59 percent of 836). Because bay anchovy are feeder fish and highly
prevalent, permit authorities are unlikely to designate them as a species of
concern subject to the proposed limitations. After excluding the bay anchovy
counts from the calculations, the impingement mortality percentage drops to 14
percent which is only slightly greater than the 12 percent proposed as the annual
average limitation. Because Unit 20's screen size of 1/8-inch is smaller than the
model technology, EPA concluded that this marginal increase in mortality was a
result of the smaller screen size. As it had for Huntley, EPA considered excluding
the data because the smaller screen would demonstrate higher impingement
mortality than the proposed model technology. For the proposed limitations, EPA
has retained the Huntley and Arthur Kill data as a conservative approach in
developing the proposed limitations, and will reevaluate its data selection for the
final rule.
In conclusion, as a result of the combined statistical modeling and engineering/biological
reviews used in developing the proposed limitations, facilities are expected to be capable
of designing and operating in a manner that will ensure compliance with the limitations.
Facilities are not expected to operate their treatment systems so as to violate the
limitations at some pre-set rate merely because probability models are used to develop
limitations.
11.2.4 Monitoring For Compliance
To demonstrate compliance with the limitations, EPA is proposing that the permit
authority specify the monitoring frequency. The monitoring should be conducted in
conditions that are representative of typical operations at the facility and fish behavior
(e.g., if the fish tend to appear primarily during night-time, then EPA expects that the
facility would monitor during this period).
• For each weekly monitoring event, the facility must determine the percentage of
organisms that die from the onset of impingement to some later time period as
specified by the permit authority (e.g., 24 to 48 hours following impingement).
o To determine compliance with the proposed monthly average limitation for a
given month, the facility would calculate and report the arithmetic average of
the impingement mortalities observed during each of the events during that
month. For example, if the facility conducted four sampling events in
December, it would calculate the monthly average from the four weekly
values. If this monthly average is less than or equal to the monthly average
limitation of 30 percent, then the facility would be in compliance for that
month.
o To determine whether compliance with the annual average limit has been
achieved, the facility would calculate and report its annual average as the
arithmetic average of the monthly averages for the year. If this annual
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
average was less than the annual average limitation of 12 percent, then the
facility would be in compliance.
11.3 Evaluation of the Entrainment Data
This section describes EPA's evaluation of the performance data related to entrainment.
Section 11.3.1 provides the calculation used to produce the percent reduction values.
Section 11.3.2 describes the initial selection and evaluation of all available entrainment
data. In any situation where data originate from numerous sources, variation in study
procedures is typical because they are independently designed and executed by different
organizations with different objectives and protocols. Section 11.3.3 evaluates the
variation in the sampling locations associated with the percent reductions. Section 11.3.4
evaluates the variation in the screen size and slot velocities associated with the percent
reductions. Section 11.3.5 describes EPA's consideration of numerical limitations on the
percent reduction of entrainment. (The 2004 Final Phase II Rule contains numerical
entrainment performance standards.)
11.3.1 Entrainment Percent Reduction Data
Entrainment is a measure of the organisms (generally juveniles, eggs, and larvae) that are
drawn past the intake structure and into the plant. In the studies EPA evaluated, facilities
sometimes measure entrainment in a canal or forebay, sometimes just prior to the
condensers, and sometimes after passing through the plant. Measurements of
entrainment usually compare organism densities "in front of the technology and
"behind" the technology. In contrast to impingement mortality, "in front of may in fact
be a measure of what is in the source water at that point in time.
Entrainment is typically characterized in the studies by measuring organism densities
both in front of and behind the technology. For studies that reported entrainment data in
this manner, EPA calculated the total densities for all species at each location (i.e.,
"front" and "behind"). EPA then calculated percent reduction as follows:
, . front-behind
percent reduction = x 100
front
Note that percent reduction does not rely on the units of density in which "front" and
"behind" measures are expressed.
11.3.2 Initial Selection and Evaluation of Entrainment Data
After examining the 178 documents in Appendix A, EPA selected entrainment data that
met the general data acceptance criteria described in Section 11.1.1. This section
describes EPA's evaluation of entrainment data for fine mesh traveling screens and
wedgewire screens. Exhibit 11-6 describes the facilities, locations, study conditions, and
species associated with these entrainment data. The data originated from the following
nine locations that represent seven states:
• Big Bend (FL) Power Station (Mote Marine Laboratory, 1987).
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
• Brunswick (NC) Steam Electric Plant (CP&L, 1985a and 1985b).
• Chalk Point (MD) intake canal within the Patuxent estuary (Weisberg et al., 1984)
• Chesapeake Bay (VA) (EPRI, 2006).
• Logan Generating Plant (NJ) and the Delaware River (Ehrler and Raifsnider,
2000)
• Oyster Creek (NJ) intake canal (EPRI, 2007).
• Portage River (OH) (EPRI, 2007).
• Sakkonet River (RI) within Narragansett Bay (EPRI, 2007).
• St. Johns River (FL) (Dames and Moore, 1979).
As noted in Exhibit 11-6, these data demonstrated performance of fine mesh traveling
screens and wedgewire screens of varying mesh sizes, were collected from 1979 to 2005,
and measured many different species in different life stages.
When EPA examined the percent reduction of total organisms for each test location and
condition as shown in Exhibit 11-7, it found a range from -24.7 percent to 95.8 percent.2
Negative values indicate an increase in organisms behind the technology compared to in
front of the technology, or what is naturally occurring in the waterbody. Such results are
not appropriate for measuring the effectiveness of the technologies to protect organisms
from entering the plant. After EPA excluded the negative values, the range was 10.1
percent to 95.8 percent. As described in the following sections, EPA examined sampling
locations, screen characteristics and life stages.
2 In its evaluations, EPA generally used the data presented in report summaries without verifying their
calculations. For example, the St. Johns Study presents summaries that include estimated values (Dames
and Moore, 1979, p. 40).
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11-6. Characteristics of Facilities with Entrainment Data and the Technology Basis
Facility
Location
Big Bend
Power Plant
Brunswick
Steam
Electric
Plant
Chalk Point
intake canal
Chesapeake
Bay
Logan Gen.
Plant
Oyster
Creek intake
canal
Portage
River
Sakkonet
River
St. Johns
River
State
FL
NC
MD
VA
NJ
NJ
OH
Rl
FL
Test
Condition
Plant/Test
Plant/Test
Test Barge
EPRI Test
Barge
Plant/Test
Test Barge
EPRI Test
Barge
EPRI Test
Barge
Test Barge
Tech-
nology
Traveling
Screens
Traveling
Screens
Wedgewire
Wedgewire
Wedgewire
Wedgewire
Wedgewire
Wedgewire
Wedgewire
Water-
body
Estuary
Estuary
Estuary
Estuary
Fresh-
water
River
Estuary
Fresh-
water
River
Estuary
Estuary
Date(s) of
Sampling
3/18/1987,
3/31/1987,
4/16/1987,
5/12/1987
Nov. 1984
to Jan.
1985
Aug. 1982
July 1983
June 2005
May and
June 1995
1/3/1979
May and
June 2004
April and
May 2004
March to
September
1979
Screen
Mesh Size
(mm)
0.5
1
1
2
1
2
3
0.5
1
1
1
2
0.5
1
0.5
1
1
2
Slot
Velocity
(mis)
not
specified
not
specified
not
specified
0.20
0.095,0.19,
0.20, 0.40
0.20
0.15,
0.3
0.15,
0.3
0.15
0.152
0.152
0.15,
0.30
0.15,
0.30
0.15,
0.30
0.15,
0.30
0.13
0.12
Species Reported in Studies
• Sciaenidae spp. (eggs)
• Bay anchovy (eggs, larvae)
• Silver perch (larvae)
• Spotted seatrout (larvae)
• Stone crab (zoea)
• Penaeus spp. (juvenile)
• Bienniidae spp. (larvae)
• Gobiidae spp. (larvae)
• Gobiesox strumosus (larvae)
• Anchoa spp.
• Spot
• Croaker
• Gobionellus spp.
• Others (at lower numbers)
• Bay anchovy (eggs, larvae)
• Naked goby (larvae)
• Bay anchovy eggs
"All larvae" which included:
• Bay anchovy
• Naked goby
• Northern pipefish
• Skilletfish
• Striped blenny
Larval fishes
Opossum shrimp (age category
unspecified).
Eggs (no species given).
Larvae for:
• Carp
• Freshwater drum
• Shad spp.
• Temperate bass
Eggs (no species given).
"All larvae" which includedof:
• Grubby
• Sand lance
• Winter flounder
Numbers of "potentially
entrainable" larvae and
juveniles for the following:
• Strongylura marina
• Lucania parva
• Menidia beryllina
• Lepomis spp.
• Gobisoma bosci
• Microgobius gulosus
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
Exhibit 11-7. Total Organisms: Percent Reduction of Entrainment by Slot Width
and Slot Velocity
Test Location
Big Bend Station
Brunswick Steam
Electric Plant
Chalk Point intake
canal (1982)
Chalk Point intake
canal (1983)
Chesapeake Bay
Logan Gen. Plant
Oyster Creek intake
canal
Portage River
Sakkonet River
St. Johns River
Screen
Slot
Width
(mm)
0.5
1
1
2
1
2
3
0.5
1
1
1
2
0.5
1
0.5
1
1
2
Slot Velocity
(mis)
not specified
not specified
not specified
0.20
0.20
0.095
0.19
0.40
0.20
0.15
0.30
0.15
0.30
0.15
0.152
0.152
0.15
0.30
0.15
0.30
0.15
0.30
0.15
0.30
0.13
0.12
"Front"
Samples:
Total Density
of all
Organisms
51,793.1
543
374.2
374.2
825.2
825.2
825.2
825.2
825.2
3,166.2
1,145.4
590.7
845
378
637
39.3
39.3
199.6
302.8
719.5
704.8
95.6
75.4
85.5
86.2
38,692,597
38,692,597
"Behind"
Samples:
Total Density
of all
Organisms
2,174.1
99
50.6
141.1
655.8
641.2
404.4
314.8
311.8
2,399
175.8
443
728
406.8
41
25.1
49
121.3
128
517.7
633.5
15.6
14.5
72.8
75.3
13,152,507
14,530,529
Density Units
of "Front"
and "Behind"
Samples
#/100m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/100m3
#/100m3
#/100m3
#/100m3
#
#/m3
#/m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#
#
Percent
Reduction
of Total
Organisms
95.8
81.8
86.5
62.3
20.5
22.3
51.0
61.9
62.2
24.2
84.7
25.0
13.8
-7.6
93.6
36.1
-24.7
39.2
57.7
28.0
10.1
83.7
80.8
14.9
12.6
66.0
62.4
11.3.3 "In Front" and "Behind" Sampling Locations
As part of its evaluation of the entrainment data, EPA considered whether variations in
sampling locations affected the percent reductions and reviewed the studies for any
conclusions about locations by the authors.
In EPA's entrainment database, studies that did not collect "in front" and "behind"
samples simultaneously (i.e., at the same point in time) typically did so within a short
11-15
-------
Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
time period (i.e., within a few hours), so that only a minor deviation in time occurred
between the paired samples used to calculate percent reduction. In all studies, plankton
nets were used to collect the samples at the given sample locations.
The Logan and Big Bend studies were the only studies whose "in front" samples did not
represent water that passed through an intake. The Logan study deviated considerably
from the others, as its "in front" samples were collected at various depths within the
source water body at some distance away from the intakes. Thus, its "in front" samples
represented general ambient densities of the source water body. The Big Bend study
actually collected its "in front" samples from directly in front of a screened intake and
was the only study listed in Exhibit 11-6 to do so.
The following is a summary of the "in front" and "behind" sampling locations in the
studies listed in Exhibit 11-6. Exhibit 11-8 also summarizes the information.
• The Big Bend study was the only study that took samples simultaneously in front
and behind of a common screened intake.
• In the Logan study, "front" samples were taken from river transects (inner
shallow, outer shallow, deep sampling) at some distance from the plant intakes.
• In the 1982 and 1983 Chalk Point studies, "front" and "behind" samples were
collected from the discharge point of a common intake; the samples were
classified as "front" or "behind" based on whether or not the wedgewire screen
covered the intake at the time of sampling. The St. Johns River study used a
similar approach, but collected fish from a holding tank in which intake water was
discharged, rather than at the intake's discharge point to the water body. Thus,
"front" and "behind" samples in these studies were collected at different points in
time.
• The Chesapeake Bay, Portage River, and Sakkonet River studies were performed
by EPRI and used the same test barge and sampling approaches. Thus, the "front"
and "behind" sample collection approaches were identical across these studies.
These samples were collected from distinct intakes, with each screen of a specific
mesh size being assigned to a specific intake. One intake was covered with a 9.5
mm mesh screen (primarily for preventing trash intake) and was used for
collecting the "front" sample. The other intakes were covered with fine-mesh
screens and were the source of the "behind" samples.
• The Oyster Creek study collected "front" samples from an unscreened intake and
"behind" samples from the pump discharge pipes. While detailed information
was not available on the sampling approach, EPA assumes it was similar to those
used in the EPRI studies, because they all used test barges.
• The Brunswick study used different sampling approaches in different months. In
November and January, the "front" and "behind" samples were collected in
consecutive 24-hour time periods. The document did not state whether the two
sampling events used the same intake or different intakes. In December, the
"front" and "behind" samples were collected simultaneously from within different
discharge weirs, similar to the Chesapeake Bay, Portage River, and Sakkonet
River studies.
11-16
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
In the EPRI studies, the intake velocities for the control intake (for collecting the "front"
samples) were designed to approximate the intake velocities associated with the
wedgewire screens (for collecting the "behind" samples). Other studies did not indicate
that the velocities for the control intake were maintained in this manner. Because the
data did not clearly establish a pattern related to sampling location (e.g., at the same
location in the Chesapeake Bay, reductions ranged from -7.6 to 13.8 percent for the same
screen mesh size), EPA concluded that factors other than sampling location (e.g.,
velocity) might better explain the ranges of percent reductions seen in Exhibit 11-7.
Exhibit 11-8. Collection Locations for "Front" and "Behind" Entrainment Samples
Study
Big Bend
Brunswick
Chalk Point
Chesapeake
Bay
Logan
Generating
Plant
Oyster Creek
Portage River
Sakkonet
River
St. Johns
River*
"Front" Sample Location
In front of both sides of Screen 3A (i.e., two
sample locations). Entrainment density
consisted of the average of the sample
densities from the two locations.
In the discharge weir of an intake covered by a
9.4 mm mesh screen. (For two of three
sampling periods, a common intake was used
between the control and fine mesh screen tests,
with the control test occurring first, while for the
third sampling period, the tests were done
simultaneously with separate intakes.)
At the discharge point associated with one of
two intakes. Samples were classified as "front"
samples if the intake was not covered by a
wedgewire screen with mesh size 3 mm or
smaller.
At the stern of the barge where water was
discharged after being withdrawn through a 9.5
mm screened intake (at the bow) and passed
through a fish pump. Intake was located
midway between the two intakes capped with
the 0.5 mm and 1 mm wedgewire screens.
Three different river transects: inner shallow,
outer (channel) shallow, and deep sampling.
Number of entrained organisms was taken to be
the average of the numbers from the deep
channel and shallow samples.
From an unscreened intake
Same test barge and sampling locations as
Chesapeake Bay
Same test barge and sampling locations as
Chesapeake Bay
Within a collection tank in which water was
discharged after being withdrawn through a 9.5
mm screen and passed through a trash pump.
The tank was one of the two tanks used by
either the 1 mm or 2 mm wedgewire screens,
and sampling occurred when the wedgewire
screens were not in operation.
"Behind" Sample Location
From an intake screenwell located behind
Screen 3A, where water was pumped and
channeled.
In the discharge weir of an intake covered by a
1.0 mm mesh screen. (For two of three
sampling periods, a common intake was used
between the control and fine mesh screen tests,
with the fine mesh test occurring last, while for
the third sampling period, the tests were done
simultaneously with separate intakes.)
At the discharge point associated with one of
two intakes. Samples were classified as
"behind" samples if the intake was screened
with either a 1 , 2, or 3 mm wedgewire screen.
At the stern of the barge where water was
discharged after being withdrawn through either
a 0.5 mm or 1 mm screened intake (at the bow)
and passed through a fish pump. Two separate
intakes were used - one for each screen size -
but only one intake was used at a time as they
shared a pump and sampling location.
Within a water filled plastic tank in which water
was discharged after flowing through the
wedgewire screen intake (located at the plant's
wet well) and passing through the centrifugal
pump.
From the pump discharge pipes.
Same test barge and sampling locations as
Chesapeake Bay
Same test barge and sampling locations as
Chesapeake Bay
Within a collection tank in which water was
discharged after being withdrawn through either
1 mm or 2 mm screens and passed through a
trash pump. Two separate screen/pump/tank
assemblies were used - one for each screen
size.
* Study document is missing pages that described sampling methodology.
11-17
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
11.3.4 Evaluation of Screen Characteristics in Reducing Entrainment
EPA considered whether screen characteristics, such as mesh size and slot velocity,
affected the percent reductions. It first reviewed the studies for any conclusions about
slot size and velocity by the authors. It then applied statistical techniques to evaluate the
effect of slot mesh size and slot velocity on values of the entrainment data.
11.3.4.1 Literature Review of Slot Size and Velocity Effects on Entrainment
For all studies identified in Exhibit 11-6 except Logan, the available documentation
included results of statistical analyses to identify the presence of significant reductions in
entrainment that are associated with changes in slot size and/or slot velocity. This section
briefly describes their evaluations and conclusions.
Most of these studies noted greater incidences of significant reductions at smaller slot
sizes. For example, the Portage and Sakkonet River studies noted that a smaller slot
width resulted in a significant reduction in larval and egg densities. At a 1.0 mm mesh
size, no significant reduction in egg entrainment was noted in these two studies, nor was
a significant reduction noted in larval entrainment within the Sakkonet River study at this
mesh size. However, a significant reduction was noted at a 0.5-mm size in each case.
These findings held for each slot velocity considered in these studies. Certain species of
larvae did not see a significant reduction in entrainment at one or both of these slot sizes,
but this may have been partially the result of limited numbers of these species found in
the samples. However, these two studies (plus the Chesapeake Bay study) did note that,
for each slot width and velocity, greater reductions in entrainment densities occurred with
increased larval lengths.
The Chesapeake Bay study noted that both slot widths (0.5 and 1.0 mm) led to significant
reductions in entrainment for eggs and most larval species, with the smaller width
yielding greater reductions.
The St. Johns River study failed to see a significant reduction in entrainment densities
(counts of organisms) between 1 mm and 2 mm slot widths. This result was noted for all
species and life stages. In the latter part of the study which extended from March to
September, the study authors report that entrainment was actually higher through the 1
mm screen compared to the 2-mm screen for certain species. They hypothesize that this
may have been due to "fouling and partial plugging" of the 1-mm screen noted in August,
which resulted in higher slot velocities. The authors note that significant variation in
entrainment could occur from one day to another due to meteorological factors such as
wind speed and river surface (waves). So it is uncertain whether any observed increases
in data collected late in the study was due to biofouling or other factors. Furthermore, the
study conclusions were based partly on estimated data for those days in which
entrainment samples were not collected. As noted by the authors, counts for some
species may have been overestimated on a particular day if the estimates were based on
counts from other days when abundance was high or meteorological factors promoted
high entrainment.
11-18
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
The Chalk Point study noted that the general effect of screen slot size on reducing the
numbers of entrained organisms was small, but measurable. While no effect could be
discerned for small organisms (<5 mm in length), approximately a 25 percent difference
in exclusion efficiency between 1-mm and 3-mm screens was noted for organisms of
intermediate size, while this percentage difference increased to approximately 80 percent
for larger organisms. Thus, organism size was an important factor in determining screen
effectiveness at small mesh sizes.
The Chalk Point studies reported entrainment results for two species: bay anchovy and
naked goby. Slot velocity had a significant effect in entrainment counts for naked goby
only. The study authors hypothesize that this was due to naked gobies inhabiting areas
close to the screens, while bay anchovies and other open water species are not as
influenced by screen slot velocities. For naked gobies, higher velocities were associated
with greater rates of entrainment. For larger gobies, increased rates were observed only
at the highest velocity (0.40 m/s), while increased rates were observed at velocities as low
as 0.095 m/s for smaller gobies.
In the EPRI studies (i.e., Chesapeake Bay, Portage, and Sakkonet), slot velocity had only
minor effects on entrainment densities (at a constant mesh size of 2 mm). The Portage
River study noted that entrainment reduction was not significantly affected by either
velocity setting. The Chesapeake Bay study noted that the slot velocity effect varied by
species, but the 0.15 m/s setting was generally more effective (by up to 30 percent) in
leading to entrainment reductions of both eggs and larvae than the 0.30 m/s setting. In
fact, this study observed a significantly greater reduction at 0.15 m/s compared to 0.30
m/s for eggs and some species of larvae.
While the Big Bend study had some unique characteristics (e.g., use of traveling screens,
location of "front" samples), the study was not designed to evaluate impacts of slot
velocity on entrainment reduction, and therefore, made no such conclusions. The study
reported effective performance relative at a 0.5 mm mesh size, based on observing
percent reductions. Eggs had a somewhat higher level of effectiveness compared to
larvae, but both life stages achieved more than 80 percent reduction. While "behind"
samples often had considerably lower densities than "front" samples, the study noted that
occasional large densities of certain specifies within "behind" samples likely reflected
schools of organisms that spawned and inhabited behind the screens.
While the Brunswick study also performed statistical analyses to investigate effects of
such factors as test period and night versus day on entrainment numbers, it did not
evaluate effects of slot mesh size or velocity (as only one fine mesh size was considered,
and slot velocity was not specified). The study did note that there was no significant
difference in entrainment densities of Gobionellus spp. between 1.0 mm and 9.4 mm
screens according to an analysis of variance (CP&L, 1985b) and implied that this
difference was significant for other species.
11-19
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule -TDD
11.3.4.2 EPA's Evaluation of Slot Size and Velocity Effects on Entrainment
After reviewing the statistical analyses in the studies, EPA performed three types of
statistical analyses to evaluate the effect of slot mesh size and slot velocity on percent
reduction data from the studies identified in Exhibit 11-6. The three types of statistical
analyses are: analysis of variance, generalized linear models, and graphical analyses.
Each is described below.
Analysis of Variance (ANOVA)
Analysis of variance models express the value of the dependent variable (i.e., the variable
on which statistical inference is to be made) as a mathematical function of predictor
variables, known as the ANOVA model. As the ANOVA model is fitted to the data,
statistical hypothesis tests are performed to determine whether different values of one or
more predictor variables significantly affect the value of the dependent variable.
EPA fit an ANOVA model with effects of slot mesh size and slot velocity to the percent
reduction in entrainment data. EPA fit this model to three different sets of percent
reduction data: to the percent reduction in total organisms, eggs only, and larvae only.
(EPA considered "larva" to be anything not specifically identified as eggs.) Appendix E
describes the analyses and results. In summary, from these analyses, EPA noted the
following:
• On average, the effect of screen size was nearly significant for percent reduction
in total organisms (p-value = 0.055) and on average percent reduction in eggs (p-
value = 0.053). Screen size did not appear to have a significant effect on average
percent reduction of larvae (p-value = 0.169). However, in all three cases, the
highest predicted mean in percent reduction occurred when the screen width was
0.5 mm. In each case, the largest differences occurred between 0.5-mm and 1.0-
mm mesh sizes.
• Slot velocity did not have a significant effect on average percent reduction in any
of the three cases (p-value = 0.183 for total organisms, p-va\ue = 0.154 for eggs,
and/>-value = 0.874 for larvae). When treating slot velocity as a categorical
variable rather than a continuous variable (similar to screen size), EPA still did
not observe a significant slot velocity effect, and the predicted means did not
follow any noticeable pattern.
Generalized Linear Models
Generalized linear models (GLMs) are statistical methods that explain the relationship
between a response variable and a set of predictors. Unlike ANOVA methods, GLMs
can be used to make inferences about the model when the data follow a distribution other
than the normal distribution. GLMs model a transformation of the mean (called the link
function) as a linear combination of the factors under investigation. For the entrainment
data, we considered two types of GLMs: Poisson regression and logistic regression.
Appendix F describes the analyses and the results. In summary from these analyses, EPA
reached the following conclusions:
11-20
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
• Both screen width and slot velocity variables were highly significant at explaining
the number of eggs entrained.
• Screen width was not significant at explaining the number of non-eggs entrained
or the number of total organisms entrained. Slot velocity also was not significant
at explaining the number of non-eggs entrained or the number of total organisms
entrained.
Graphical Analysis
In addition to the ANOVA, EPA examined a series of plots for patterns in mesh sizes and
slot velocities. The plots are provided in Exhibits 11-9 through 11-12 and 11-14 through
11-15. They display percent reductions for total organisms, eggs, and larvae (non-eggs).
Here are EPA's conclusions:
• Total Organisms: Exhibits 11-9 and 11-10 show a wide range of percent
reductions of total organisms at any screen size and slot velocity. (Exhibit 11-7
provides the percent reduction values plotted in the figures.)
• Eggs: Exhibits 11-11 and 11-12 show that:
o 0.5-mm screens generally reduce over 80 percent of the entrainment of eggs.
The one exception is associated with a slot velocity of 0.3 meters per second
(m/s). As shown in Exhibit 11-13 which presents percent reduction of eggs,
this value is 19 percent from the Chesapeake Bay Study. EPRI (2006) notes
that "At the salinity closest to that observed at our test site (15 ppt) the mean
diameters of the major and minor axes were estimated to be 0.97 and 0.90
mms, respectively." (page 4-30) At the slower slot velocity of 0.15 m/s,
Chesapeake study reports 87 percent reduction. EPA concludes that the
higher slot velocity forced more eggs through the 0.5-mm screen, and thus,
the lower velocity is more protective.
o 1-mm screens are generally reducing relatively little entrainment. Most
values are below 20 percent. The one exception, 96 percent, has a slot
velocity of 0.15 m/s and was observed during the Portage River study.
• Larvae: Exhibits 11-14 and 11-15 have similar patterns to those for total
organisms. There are wide ranges of percent reductions at any screen size and
velocity. Exhibit 11-16 provides the percent reductions for each study condition.
11-21
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11-9. Percent Reduction of Total Organisms Entrained by Slot Velocity and
Screen Size, with Screen Size on the Horizontal Axis
E>
o
S 40
Si
S.
n
a
Screen Size (mm)
Exhibit 11-10. Percent Reduction of Total Organisms Entrained by Slot Velocity
and Screen Size, with Slot Velocity on the Horizontal Axis
0> 60
20
-20
B
Slot Velocity
11-22
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
Exhibit 11-11. Percent Reduction of Eggs Entrained by Slot Velocity and Screen
Size, with Screen Size on the Horizontal Axis
o 40
-20
-40
I
0.5
1.5
2.5
35
Screen Size (mm)
Exhibit 11-12. Percent Reduction of Eggs Entrained by Slot Velocity and Screen
Size, with Slot Velocity on the Horizontal Axis
100
40
-40
*
O
-*-
O
IT
D
Slot Velocity
11-23
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11-13. Eggs: Percent Reduction of Entrainment
Test Location
Big Bend Station
Chalk Point intake
canal (1983)
Chesapeake Bay
Portage River
Sakkonet River
Screen
Slot
Width
(mm)
0.5
3
0.5
0.5
1
1
0.5
0.5
1
1
0.5
0.5
1
1
Slot Velocity
(mis)
not specified
0.20
0.15
0.30
0.15
0.30
0.15
0.30
0.15
0.30
0.15
0.30
0.15
0.30
"Front"
Samples:
Total Density
of Eggs
51,455
2,341
998.8
503.1
774
271.7
45.1
42
102.9
117.2
14.5
22.8
42
42.9
"Behind"
Samples:
Total Density
of Eggs
2,133
1,707
134.1
406.2
682.3
356.9
1.1
2.8
4.5
97.1
1.1
0
30.6
39.6
Density Units
of "Front" and
"Behind"
Samples
#/100m3
#/1000m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
Percent
Reduction
of Eggs
95.9
27.1
86.6
19.3
11.8
-31.4
97.6
93.3
95.6
17.2
92.4
100.0
27.1
7.7
Exhibit 11-14. Percent Reduction of Larvae Entrained by Slot Velocity and Screen
Size, with Screen Size on the Horizontal Axis
40
t 20
-40
D
D
Screen Size (mm)
11-24
-------
§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 11: Impingement Mortality
Limitations and Entrapment Data
Exhibit 11-15. Percent Reduction of Larvae Entrained by Slot Velocity and Screen
Size, with Slot Velocity on the Horizontal Axis
0)
E
ro
•5 40-
O
|
0)
01
O
£
0.
-dn
•
0
•
•
A
0
•
•
)0 0.10
+
A A
•
9
A
5 •
•
0.20 0.30 0.40 0.
A
Slot Velocity
11-25
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Chapter 11: Impingement Mortality
Limitations and Entrapment Data
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11-16. Larvae: Percent Reduction of Entrainment
Test Location
Big Bend Station
Brunswick Steam
Electric Plant
Chalk Point intake
canal (1982)
Chalk Point intake
canal (1983)
Chesapeake Bay
Logan Gen. Plant
Oyster Creek intake
canal
Portage River
Sakkonet River
St. Johns River
Screen
Slot
Width
(mm)
0.5
1
1
2
1
2
3
0.5
1
1
1
2
0.5
1
0.5
1
1
2
Slot
Velocity
(mis)
not specified
not specified
not specified
0.20
0.20
0.095
0.19
0.40
0.20
0.15
0.30
0.15
0.30
0.15
0.152
0.152
0.15
0.30
0.15
0.30
0.15
0.30
0.15
0.30
0.13
0.12
"Front"
Samples:
Total Density
of Larvae
338.1
543
374.2
374.2
825.2
825.2
825.2
825.2
825.2
825.2
146.6
87.6
71
106.3
637
39.3
39.3
154.5
260.8
616.6
587.6
81.1
52.6
43.5
43.3
38692597
38692597
"Behind"
Samples:
Total Density
of Larvae
41.1
99
50.6
141.1
655.8
641.2
404.4
314.8
311.8
692
41.7
36.8
45.7
49.9
41
25.1
49
120.2
125.2
513.2
536.4
14.5
14.5
42.2
35.7
13152507
14530529
Density Units
of "Front"
and "Behind"
Samples
#/100m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/100m3
#/100m3
#/100m3
#/100m3
#
#/m3
#/m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#
#
Percent
Reduction
of
Larvae
87.8
81.8
86.5
62.3
20.5
22.3
51.0
61.9
62.2
16.1
71.6
58.0
35.6
53.1
93.6
36.1
-24.7
22.2
52.0
16.8
8.7
82.1
72.4
3.0
17.6
66.0
62.4
11-26
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Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule - TDD Limitations and Entrapment Data
11.3.5 Consideration of Entrainment Limitation
In its consideration of potential entrainment limitations, EPA summarized the data as
shown in Exhibit 11-17 to distinguish between different life stages, slot sizes, and
velocities. EPA then focused on data representing the entrainment of eggs, because, of
all life stages, eggs are the least able to avoid being entrained (in other words eggs have
no avoidance capability), and because eggs pose the smallest life-stage that any screens-
based technology must be able to protect. To develop a limitation that would be
protective of eggs, EPA evaluated the performance of circular wedgewire screens with
mesh sizes of 0.5-mm screens and a slot velocity of 0.5 feet per second. Many eggs are
larger than 0.5-mm screens, and thus, a mesh size of 0.5 mm would reduce the likelihood
of entrainment. In addition, the relatively low velocity of 0.5 feet per second means that
organisms larger than 0.5 mm are less likely to be squeezed or forced through the mesh.
EPA found, on average, the screen size and velocity specifications resulted in 92 percent
reduction of eggs. However, as explained in Chapter 6, EPA has concerns about the
technical availability of requiring 0.5-mm fine mesh screens for this industry. As a
consequence, EPA considered developing limitations based upon a larger mesh size, such
as 1 or 2 mm, but concluded that eggs, because of their small size, would generally pass
through the larger mesh sizes. After reviewing the documents listed in Appendix A, EPA
further notes that none of the studies evaluated egg entrainment reduction by 2-mm fine
mesh screens. As explained in the preamble, EPA has not proposed entrainment
limitations.
11-27
-------
Exhibit 11-17. List of Percent Reduction in Entrainment Data by Study, Screen Size, and Slot Velocity, and Summary Statistics
Organ-
isms
Total
Eggs
Only
Larvae
(non-
eggs)
Only
Screen
Size
(mm)c
0.5
1.0
2.0
0.5
1.0
0.5
1.0
2.0
Slot Velo-
city (mis)
0.15
0.30
NS
All
<0.15
>0.15
NS
All
<0.15
>0.15
NS
All
0.15
0.30
NS
All
<0.15
>0.15
All
0.15
0.30
NS
All
<0.15
>0.15
NS
All
<0.15
>0.15
NS
All
Study (Test Location)
Big
Bend
95.8
Bruns-
wick
Chalk
Point
1982
Chalk
Point
1983
Chesa-
peake Bay
84.7
25.0
Logan
Plant
Oyster
Creek
Portage
River
39.2
57.7
Sak-
konet
River
83.7
80.8
St.
Johns
River
81.8
86.5
20.5
13.8
-7.6
93.6
36.1
28.0
10.1
14.9
12.6
66.0
62.3
51.0
61.9,
22.3,
62.2
-24.7
62.4
95.9
86.6
19.3
97.6
93.3
92.4
100.0
11.8
-31.4
95.6
17.2
27.1
7.7
87.8
71.6
58.0
22.2
52.0
82.1
72.4
81.8
86.5
20.5
35.6
53.1
93.6
36.1
16.8
8.7
3.0
17.6
66.0
62.3
51.0
61.9,
22.3,
62.2
-24.7
62.4
Summary Statistics
Mina
39.2
25.0
95.8
25.0
13.8
-7.6
81.8
-7.6
-24.7
22.3
62.3
-24.7
86.6
19.3
95.9
19.3
11.8
-31.4
-31.4
22.2
52.0
87.8
22.2
3.0
8.7
81.8
3.0
-24.7
22.3
62.3
-24.7
Minb
39.2
25.0
95.8
25.0
13.8
10.1
81.8
10.1
51.0
22.3
62.3
22.3
86.6
19.3
95.9
19.3
11.8
7.7
7.7
22.2
52.0
87.8
22.2
3.0
8.7
81.8
3.0
51.0
22.3
62.3
22.3
Max
84.7
80.8
95.8
95.8
93.6
20.5
86.5
93.6
62.4
62.2
62.3
62.4
97.6
100
95.9
100
95.6
17.2
95.6
82.1
72.4
87.8
87.8
93.6
53.1
86.5
93.6
62.4
62.2
62.3
62.4
Averageb
69.2
54.5
95.8
66.7
42.1
14.4
84.2
42.2
56.7
48.8
62.3
53.7
92.2
70.9
95.9
83.6
44.8
12.5
31.9
58.6
60.8
87.8
63.7
41.9
25.0
84.2
43.3
56.7
48.8
62.3
53.7
Median"
83.7
57.7
95.8
80.8
32.1
12.6
84.2
28.0
56.7
61.9
62.3
62.1
92.4
93.3
95.9
93.3
27.1
12.5
17.2
71.6
58.0
87.8
71.6
35.9
19.1
84.2
35.9
56.7
61.9
62.3
62.1
TO
Q 3
it
3- a.
O =f
an
U)
m
x
-8
a
TO
Q.
C7
C7
a Includes negative values
b Excludes negative values
0 Does not include data on the 3.0 mm mesh size from the 1983 Chalk Point study.
NS = not specified
-------
Chapter 11: Impingement Mortality
§ 316(b) Existing Facilities Proposed Rule-TDD Limitations and Entrapment Data
11.4 References
Battelle. 2008. "316b: Laboratory Test Data Related to Entrainment." Prepared under
EPA Contract No. EP-C-05-030. October 17, 2008.
Beak Consultants, Inc. 2000a. Post-Impingement Fish Survival at Dunkirk Steam Station.
Winter, Spring, Summer and Fall 1998-1999. Prepared for NRG Dunkirk Power,
LLC. 26 January 2000. (DCN 5-4327)
Beak Consultants, Inc. 2000b. Post-Impingement Fish Survival at Huntley Steam Station.
Winter and Fall 1999. Prepared for Niagara Mohawk Power Corp. 10 April 2000.
(DCN 5-4325)
CEC. 1996. Arthur Kill Generating Station Diagnostic Study and Post-Impingement
Viability Substudy Report. Prepared by Consolidated Edison Company of New
York, Inc. 31 January 1996. (DCN 5-4326)
CP&L. 1985a. Brunswick Steam Electric Plant, Cape Fear Studies: Interpretive Report.
Carolina Power & Light Company. August 1985.
CP&L. 1985b. Brunswick Steam Electric Plant, 1984 Biological Monitoring Report.
Biology Unit, Environmental Services Section, Carolina Power & Light Company.
August 1985.
Dames and Moore. 1979. Seminole Plant Units No. 1 and No. 2: 316b Study and Report.
Prepared for Seminole Electric Cooperative, Inc. November 1979.
Electric Power Research Institute (EPRI). 2006. Field Evaluation ofWedgewire Screens
for Protecting Early Life Stages of Fish at Cooling Water Intake Structures:
Chesapeake Bay Studies. Palo Alto, CA: Electric Power Research Institute.
1012542.
Electric Power Research Institute. 2007. Fish Protection at Cooling Water Intake
Structures: A Technical Reference Manual. Palo Alto, CA: Electric Power
Research Institute. 1014934.
Electric Power Research Institute. 2008. Laboratory Evaluation of Fine-Mesh Traveling
Water Screens for Protecting Early Life Stages of Fish at Cooling Water Intakes.
Palo Alto, CA: Electric Power Research Institute, Inc. 1014021.
Ehrler, C, and Raifsnider, C. 2000. Evaluation of the effectiveness of intake wedgewire
screens. Environmental Science & Policy. 3:S361-S368. (DCN 5-4335)
Mote Marine Laboratory. 1987. Fine Mesh Screen (FMS) Optimization Study: A
Technical Report. Prepared for Environmental Planning, Tampa (FL) Electric
Company. 2 July 1987. (DCN 5-4371)
Ronafalvy, J.P., et al. 2000. "Circulating water traveling screen modifications to improve
impinged fish survival and debris handling at Salem Generating Station."
Environmental Science & Policy, 3, pages S377-S382. (DCN 5-4333).
11-29
-------
Chapter 11: Impingement Mortality
Limitations and Entrapment Data § 316(b) Existing Facilities Proposed Rule-TDD
Weisberg, S.B., Burton, W.H., Ross, E.A., and Jacobs, F. 1984. The Effects of Screen Slot
Size, Screen Diameter, and Through-Slot Velocity on Entrainment ofEstuarine
Ichthyoplankton Through Wedge-Wire Screens. Prepared by Martin Marietta
Environmental Systems for the Maryland Department of Natural Resources.
August 1984. (DCN 5-4008)
11-30
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix A
Appendix A to Chapter 11: Studies
The tables in this appendix provide information about the studies and data evaluated for
Chapter 11.
• Exhibit 11 A-l identifies the documents and whether they:
o Included impingement/entrainment data (i.e., counts and/or percentages);
o Were used to develop the proposed limitations (for impingement mortality) or
the entrainment design approaches, and reasons for using or not using the data
in the evaluations; and
o Are included in the performance database (DCN 10-5400).
• Exhibit 11A-2 identifies the subset of documents and facilities with impingement
mortality data.
• Exhibit 11A-3 identifies the subset of documents and facilities with entrainment
density data ("front" and "behind").
• Exhibit 11A-4 identifies the subset of documents and facilities with entrainment
mortality data (counts and/or percentages).
HA-l
-------
Exhibit 11A-1: List of Documents Reviewed for Data on Impingement and Entrainment For Use in Preparing Proposed
Limitations on Impingement Mortality and BTA Design Standards for Entrainment
ID
4
5
8
16
17
150
18
DCN
DON 5-4053
DCN 1-301 9-
BE
DCN 4-4002B
DCN 5-4397
DCN 5-431 3
DCN 5-441 4
Authors
CCI
Environmental
Services
US EPA Region
IV
EPRI
Lawler Matusky &
Skelly Engineers
AWH Turnpenny,
R Wood, and KP
Thatcher
Ecological
Analysts Inc.
Title
Zooplankton Entrainment
Survival at the Anclote Power
Plant Near Tarpon Springs,
Florida
In the Matter of Florida Power
Corporation, Crystal River
Power Plant, Units 1 , 2 and 3,
Citrus County Florida, NPDES
Permit No. FL0000159, Findings
and Determinations, per 33
USC 1326
Fish Protection at Cooling Water
Intakes: Status Report
Intake Research Facilities
Manual
Fish Deterrent Field Trials at
Hinkley Point Power Station,
Somerset, 1993-1994
Potrero Power Plant CWIS
316(b) Demonstration
Date"
1994
1988
1999
1985
1994
1980
Impingement Data
Pre-
sent?
Yes
Yes
Yes*
Yes*
Used?
No
No
No
No
Reasons for Use/Non-Use
No impingement data
Brief mention of total annual
impingement of two shrimp and
crab species is given in tons. No
impingement mortality data
reported. Limited information
available on technology, which is
not modified traveling screens.
Summary report containing data
from various studies and
facilities. Some acceptable
impingement mortality data
found in this report were
obtained from their original
source or from a later update
(2007) of this report instead.
No impingement data. (Report
contains only detailed
descriptions of intake testing
facilities.)
Study offish diversion using
non-BTA technology (sound
generating system)
Used course mesh traveling
screens, but not modified
features to make it BTA.
Entrainment Data
Pre-
sent?
Yes*
Yes*
Used?
No
No
Reasons for Use/Non-Use
Focused on mortality resulting
from entrainment through system
and dilution pumps, rather than
measuring entrainment reduction.
Technology was alternate
reduced intake flow, and not fine-
mesh screens.
No entrainment data.
No entrainment data.
No entrainment data.
No entrainment data.
Only reported estimated
entrainment abundance and
survival, and not reduction in
density, at a single sample point.
Used coarse mesh rather than
fine mesh screens.
-------
Exhibit 11A-1: (Continued)
ID
38
39
40
41
42
43
44
45
DCN
DON 5-4391
DCN 5-4389
DCN 5-441 7
DCN 5-4322
DCN 5-4388
DCN 5-4394
DCN 5-4327
DCN 5-441 9
Authors
JB Hutchinson
and JA Matousek
J Homa, M
Stafford-Glass,
and ME Connors;
Ichthyological
Associates, Inc.
Lawler, matusky,
& Skelly
Engineers LLP
Lawler, Matusky,
& Skelly
Engineers LLP
Stone and
Webster
Engineering
Corporation
Roberto Pagano
and Wade H.B.
Smith - Mitre
Corporation
Beak Consultants
Incorporated
Tennessee Valley
Authority
Title
Evaluation of a Barrier Net
Used to Mitigate Fish
Impingement at a Hudson River
Power Plant Intake
An Evaluation of the
Effectiveness of the Strobe
Light Deterrent System at
Milliken Station on Cayuga
Lake, Tompkins County, New
York
Lovett Generating Station
Gunderboom System
Evaluation Program
Lovett Generating Station
Gunderboom Deployment
Program, 2000
Evaluation of the Eicher Screen
at Elwha Dam: Spring 1990
Test Results
Recent Developments in
Techniques to Protect Aquatic
Organisms at the Water Intakes
of Steam-Electric Power Plants
Post-Impingement Fish Survival
at Dunkirk Steam Station 1998-
1999
A State-of-the-Art Report on
Intake Technologies
Date"
1988
1994
1998
2001
1991
1977
2000
1976
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Yes
Used?
No
No
Yes
No
Reasons for Use/Non-Use
Did not use modified traveling
screen technology. Did not
record mortality data within 48
hours of impingement.
No impingement data.
No impingement data.
No impingement data.
No impingement data. Data
represent fish diversion
associated with a prototype
installation operated under
highly controlled conditions.
Impingement data from Surry
and Barney Davis Power
Stations represent fish bucket
screens and double-exit
traveling screens, respectively
but the data only represent
mortality immediately following
impingement.
Mortality data were reported at
24-hour post-impingement for
Ristroph-type dual flow traveling
screens.
Data represent laboratory
studies and do not represent
traveling screens with BTA
features.
Entrainment Data
Pre-
sent?
Yes
Yes*
Yes*
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
No entrainment data.
Used strobe light deterrent
system rather than fine mesh
screen technology. Sampling
done at a single collection point.
Used Gunderboom system
rather than fine mesh screen
technology.
Used Gunderboom system
rather than fine mesh screen
technology.
Data represent fish diversion
associated with a prototype
installation operated under
highly controlled conditions.
Screens classified as coarse
mesh.
No entrainment data
No entrainment data
Percentage entrainment data are
reported for various mesh sizes,
but entrainment reduction is not
reported.
-------
Exhibit 11A-1: (Continued)
ID
46
47
48
49
50
51
52
DCN
DON 4-4002V-
R12
DCN 10-5435
DCN 5-431 4
DCN 5-4396
DCN 10-5438
DCN 5-4325
DCN 5-4371
Authors
Lawler, Matusky
& Skelly
Engineers
Stone and
Webster
Environmental
Technology and
Services
AWH Turnpenny,
JM Fleming, KP
Thatcher & R
Wood (Fawley
Aquatic Research
Laboratories,
Ltd.)
David E. Bailey,
Jules J. Loos,
Elgin S. Perry
Drs. P.A.
Henderson and
R.M. Seaby
Beak
Consultants, Inc.
Mote Marine
Laboratory
Title
Intake Technologies: Research
Status
Evaluation of the Modular
Inclined Screen at the Green
Island Hydroelectric Project:
1995 Test Results
Trials of an Acoustic Fish
Deterrent System at Hartlepool
Power Station
Studies of Cooling Water Intake
Structure Effects at Potomac
Electric Power Company
Generating Stations
Technical Evaluation of
USEPA's Proposed Cooling
Water Intake Regulations for
New Facilities
Post-Impingement Fish Survival
at Huntley Steam Station
(Winter and Fall, 1999)
Fine Mesh Screen (FMS)
Optimization Study
Date"
1989
1996
1995
Unk.
2000
2000
1987
Impingement Data
Pre-
sent?
Yes*
Yes
Yes*
Yes
Yes*
Used?
No
No
No
No
Yes
Reasons for Use/Non-Use
Summary report of impingement
mortality data from various
facilities. Typically, only
immediate impingement mortality
is provided, or technologies were
not traveling screens with BTA
features.
No impingement data.
Study measured how fish
impingement rate (rather than
mortality) is reduced when a
non-BTA technology (acoustic
deterrent system) is in place.
Impingement counts, but not
mortality, are reported for
several facilities. Technologies
were not fully documented (but
were not traveling screens with
BTA features).
Only estimated annual fish
impingement reported to assess
impact of pumping rate on
impingement at various plants.
Technologies not fully
documented.
Mortality data were reported at
24-hour post-impingement for
Ristroph-type dual flow traveling
screens.
No impingement data.
Entrainment Data
Pre-
sent?
Yes*
Yes*
Yes
Yes*
Used?
No
No
No
Yes
Reasons for Use/Non-Use
No entrainment data
Controlled study performed in a
test facility near the power plant.
Fish were injected into the test
facility, and numbers diverted
from the screens and collected
at bypass were reported rather
than entrainment.
No entrainment data
Entrainment data expressed as
percent loss or biomass, and not
percent reduction in density.
Technologies were not fully
documented (but were not fine-
mesh screens).
Only entrainment counts were
reported for various plants, and
not "before/after" measurements.
Technologies not fully
documented.
No entrainment data
Entrainment density data were
reported from front and behind
screen 3A for representative
important species.
-------
Exhibit 11A-1: (Continued)
ID
53
54
209
55
56
66
57
58
97
59
60
DCN
DON 5-4378
DCN 5-4326
DCN 2-01 3L-
R1
DCN 5-4006
DCN 6-2074
DCN 2-01 7A-
R7
DCN 5-4337
DCN 5-4354
DCN 10-5448
Authors
John S. Stevens,
Jr., and Milton S.
Love
Consolidated
Edison Company
of New York
American Electric
Power Service
Corporation
TG Ringger,
Baltimore Gas &
Electric
EPRI
Delta Fish
Facilities
Technical
Coordination
Committee
E.S. Fritz
Latvaitis et al.
Edited by Loren
Jensen
Title
Chapter 10: San Onofre Units 2
and 3 316(b) Demonstration,
The Effectiveness of the Fish
Return System
Arthur Kill Generating Station
Diagnostic Study and Post-
Impingement Viability Substudy
Report
Cardinal Plant Demonstration
Document
Investigations of Impingement
of Aquatic Organisms at the
Calvert Cliffs Nuclear Power
Plant, 1975-1995
Review of Entrainment Survival
Studies: 1970-2000
Preliminary Design Criteria for
the Peripheral Canal Intake Fish
Facilities
Cooling Water Intake Screening
Devices Used to Reduce
Entrainment and Impingement
Third National Workshop on
Entrainment and Impingement -
- Impingement Studies at Quad-
Cities Station, Mississippi River
Date"
Unk.
2000
1981
2000
2000
1981
1980
1976
Impingement Data
Pre-
sent?
Yes
Yes*
Yes
Yes*
Yes*
Used?
No
Yes
No
No
No
Reasons for Use/Non-Use
Impingement mortality measured
at 96 hours. Technology
involved louvers and angled
screens.
Mortality data utilized were
collected at 24-hour post-
impingement at Screens No. 24
and 31 which featured Ristroph-
type dual flow traveling screens.
Limited mortality data reported in
a chapter com paring
performance at Arthur Kill and
Indian Point plants were not
used.
Impingement data consist solely
of impinged fish, with no
mortality information. Traveling
screens were not modified.
Annual impingement counts and
mortality are estimated.
Traveling screens were not
modified.
No impingement data.
No impingement data.
No impingement data.
Losses of standing crop to
impingement are reported rather
than impingement mortality.
Data are estimated. Traveling
screens were not modified.
Entrainment Data
Pre-
sent?
Yes
Yes
Yes
Used?
No
No
No
Reasons for Use/Non-Use
No entrainment data
While fine-mesh screens were
evaluated, samples were
measured downstream and used
to estimate entrainment (with no
paired "front" sample results to
compare with).
Entrainment data consist solely
of numbers offish that passed
through coarse-mesh screens.
No entrainment data
Summary report consisting
solely of entrainment survival
data summaries from several
plants, with no data reported on
reduction in entrainment or on
the specified technologies used.
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
61
62
63
64
65
69
70
71
DCN
DON 5-4343
DCN 10-5448
DCN 5-4381
DCN 5-4334
DCN 10-5453
DCN 5-4346
DCN 5-4347
DCN 5-4374
Authors
Department of
Fish and Game
and the
Department of
Water Resources
Thomas & Miller.
Edited by Loren
Jensen
Ronald Raschke -
US EPA
James B.
McLaren
Richard Horwitz
Q.E. Ross; D.J.
Dunning; J.K.
Meneszees;
M.J.Kenn Jr.;
G.Tiller
Q.E. Ross; D.J.
Dunning; J.K.
Meneszees;
M.J.Kenn Jr.;
G.Tiller
N.J. Thurber and
D.J Jude, Great
Lakes and Marine
Waters Center,
University of
Michigan
Title
Memorandum Report on the
Peripheral Canal Fish Return
Facilities
Third National Workshop on
Entrainment and Impingement -
-Impingement Studies at Oyster
Creek Generating Station,
Forked River, New Jersey, from
Sept. to Dec. 1975
Finding of Fact for Biological
and Environmental 316
Demonstration Studies
Fish Survival on Fine Mesh
Travelling Screens
Lecture Notes on Coastal and
Estuarine Studies - Ecological
Studies in the Middle Reach of
the Chesapeake Bay -
Impingement Studies
Reducing Impingement of
Alewives with High Energy
Frequency Sound at a Power
Plant Intake in Lake Ontario
Response of Alewives to High
Frequency Sound at a Power
Plant Intake on lake Ontario
Impingement Losses at the DC
Cook Nuclear Power Plant
During 1975-1 982 With a
Discussion of Factors
Responsible and Possible
Impact on Local Populations
Date"
1971
1976
1983
2000
1987
1996
1993
1985
Impingement Data
Pre-
sent?
Yes*
Yes
Yes*
Yes*
Yes
Yes
Yes
Used?
No
No
No
No
No
No
No
Reasons for Use/Non-Use
No impingement data.
Traveling screens were not
modified. Reported
impingement mortality data
appear to represent only
immediate mortality, although
report notes delayed mortality
was examined.
Only total annual impingement
counts were reported for selected
species, and not impingement
mortality. No information given to
verify use of BTA.
Impingement mortality data
reported only at 0 and 96 hours
post-impingement.
Traveling screens were not
modified with BTA features. Only
immediate mortality following
impingement appears to be
reported in most cases.
Study used non-BTA technology
(sound generating system)
Study used non-BTA technology
(sound generating system)
Estimated annual impingement
totals without noting mortality.
Used non-BTA technology
(traveling screens with no
modification). Data are of
questionable quality.
Entrainment Data
Pre-
sent?
Yes
Used?
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
Only total annual entrainment
counts were reported for selected
species, with no "front" data to
allow for percent reduction to be
calculated. Technology likely not
fine-mesh screens.
No entrainment data
No entrainment data
No entrainment data
No entrainment data. (Although
densities offish near the intakes
were collected, the densities
were associated with the sound
deterrent system either on or off).
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
73
74
75
76
77
78
79
80
81
DCN
DON 5-4301
DCN 5-4330
DCN 5-4302
DCN 5-4303
DCN 5-4304
DCN 5-4300
DCN 5-4357
DCN 5-4307
DCN 10-5465
Authors
A.W.H.
Turnpenny
Rob Brown
A.W.H.
Turnpenny
A.W.H.
Turnpenny
A. Turnpenny, J.
Nedwell
A.W.H.
Turnpenny, C.J.L.
Taylor
Fish and Wildlife
Service - US
Department of the
Interior
H.H. Reading
D.T. Michaud,
E.P. Taft
Title
Fish Return at Cooling Water
Intakes
The potential of strobe lighting
as a cost-effective means for
reducing impingement and
entrainment
Exclusion of Salmonid Fish
From Water Intakes
Bubble Curtain Fish Exclusion
Trials at Heyshaam 2 Power
Station
Fish Behaving Badly
An Assessment of the Effect of
the Sizewell Power Stations on
Fish Populations
Impacts of Power Plant Intake
Velocities on Fish
Retention of Juvenile White
Sturgeon, Acipenser
Transmontanus, by Perforated
Plate and Wedgewire Screen
Materials
Recent Evaluations of Physical
and Behavioral Barriers for
Reducing Fish Entrainment at
Hydroelectric Plants in the
Upper Midwest
Date"
1992
2000
1988
1993
2002
2000
1977
1982
2000
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Used?
No
No
No
Reasons for Use/Non-Use
Only ranges of impingement
mortality are presented for one
facility, for each of five levels of
fish resistance/sensitivity.
Minimal information was available
to assess BTA use. One study
measured only 96 hour survival
rate.
No impingement data. Study
used non-BTA technology (strobe
lighting system)
No impingement data.
Data correspond to "fish catch on
screens." Study assessed non-
BTA technology (bubble curtain,
with no information on screens
used).
No impingement data.
Impingement data expressed as
"losses to the fishery" as biomass
rather than mortality. Facilities do
not appear to have used BTA.
No impingement data.
Laboratory study that did not
collect impingement mortality
data.
No impingement data.
Entrainment Data
Pre-
sent?
Yes*
Used?
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
Study evaluated different
technologies (e.g., barrier net,
sound, strobe lights, air bubble
devices) other than use of fine
mesh screens.
-------
Exhibit 11A-1: (Continued)
ID
82
84
85
86
94
95
96
98
DCN
DON 10-5466
DCN 5-4335
DCN 5-4333
DCN 6-5068
DCN 5-4344
DCN 5-4332
DCN 5-4331
DCN 5-4338
Authors
E.R. Guilfoos,
R.W. Williams,
I.E. Rourke, P.B.
Latvaitis, J.A.
Gulvas, R.H.
Reider
C. Ehrler, C.
Raifsnider
John P.
Ronafalvy, R. Roy
Chessman,
William M.
Matejek
Lawler, Matusky,
and Skelly
KeySpan
Corporation
Andrew E. Jahn,
Kevin T.
Herbinson
David R. Sager,
Charles H.
Hocutt, Jay R.
Stauffer Jr.
Delta Fish
Facilities
Technical
Coordinating
Committee
Title
Six Years of Monitoring the
Effectiveness of a Barrier Net at
the Ludington Pumped Storage
Plants on Lake Michigan
(Waterpower 95)
Evaluation of the Effectiveness
of Intake Wedgewire Screens
Circulating water traveling
screen modifications to improve
impinged fish survival and
debris handling at Salem
Generating Station
Lovett Generating Station
Gunderboom Evaluation
Program
Screenwash return water
modification study, Glennwood
and Port Jefferson Power
Stations
Designing a light-meditated
behavioral barrier to fish
impingement and a monitoring
program to test its effectiveness
at a coastal power station
Avoidance behavior of Morone
americana, Leiostomus
xanthurus and Brevooritia
tyrannus to strobe light as a
method of impingement
mitigation
Justification for Abandonment of
Further Consideration of the
Louver Fish Screen for an
Intake Facility for the Peripheral
Canal
Date"
1995
2000
2000
1996
2002
2000
2000
1981
Impingement Data
Pre-
sent?
Yes*
Yes
Yes
Used?
No
No
No
Reasons for Use/Non-Use
No impingement data.
No impingement data.
Impingement data for only one
species (weakfish) were
available.
No mortality data. No information
on type of traveling screens used
(focus is on Gunderboom
evaluation).
Only monthly totals reported. No
information given on type of
technology. No mortality data.
No impingement data. Study
used non-BTA technology (light
used as stimulus for attracting
fish to bypass).
No impingement data.
Laboratory study that used non-
BTA technology (strobe light and
bubble curtain deterrents).
No impingement data
Entrainment Data
Pre-
sent?
Yes*
Yes
Used?
Yes
No
Reasons for Use/Non-Use
No entrainment data with regard
to fine-mesh screens (instead,
the percentage offish prohibited
from entering a barrier net
enclosure was measured).
Entrainment data represent
samples collected "behind" 1 mm
screens, while "front" sample
data were taken as the average #
fish from samples collected from
deep channel and shallow
stations.
No entrainment data
Estimated entrainment counts are
provided only with and without
Gunderboom in place.
No entrainment data
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
99
100
101
102
103
104
105
DCN
DON 5-4339
DCN 5-4340
DCN 5-4341
DCN 5-4342
DCN 5-4360
DCN 5-4362
DCN 5-4376
Authors
Delta Fish
Technical
Coordinating
Committee
Delta Fish
Technical
Coordinating
Committee
Delta Fish
Technical
Coordinating
Committee
Delta Fish
Facilities
Technical
Coordinating
Committee
CD Goodyear,
Great Lakes
Fishery
Laboratory
LW Barnthouse et
al, Oak Ridge
National
Laboratory
JH Balletto and
HW Brown,
American Electrip
Power
Title
Horizontal Traveling Fish
Screen Status
Justification for Abandonment of
Further Consideration of the
Filtration Concept for an Intake
Facility for the Peripheral Canal
Justification for Eliminating from
Further Consideration the
Horizontal Rotary Drum Screen
for the Peripheral Canal
Justification for Proceeding with
an "Off-River" Intake Concept
for the Peripheral Canal
Evaluation of 31 6(b)
Demonstration: Detroit Edison's
The Impact of Entrainment and
Impingement on Fish
Populations in the Hudson River
Estuary (Volume II)
Kammer Plant Demonstration
Document for PL 92-500
Section 31 6(b)
Date"
1980
1979
1979
1979
1978
1982
1980
Impingement Data
Pre-
sent?
Yes
Yes*
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
Laboratory study. No mortality
data or information given on
whether traveling screens were
modified.
No impingement data
No impingement data
No impingement data
No mortality data. No indication
that traveling screens were
modified. Data appear to be
estimates.
Estimated monthly data provided.
For three plants with
impingement mortality data,
holding times exceed 48 hours.
Only estimated total impingement
counts were reported, with no
mortality data. Traveling screens
were not modified to include BTA
features.
Entrainment Data
Pre-
sent?
Yes
Yes
Used?
No
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
No entrainment data
No entrainment data
Coarse mesh screens used. No
"front" data.
No entrainment data
Only estimated total entrainment
counts were reported from a
single sampling point. Coarse
mesh screens used.
-------
Exhibit 11A-1: (Continued)
ID
106
107
108
109
110
111
112
113
114
DCN
DON 6-5037
DCN 6-5046O
DCN 5-4409
DCN 5-441 8
DCN 5-4305
DCN 5-441 1
DCN 5-4336
DCN 4-1 326
DCN 5-4306
Authors
Stone & Webster
Engineering
John Young,
William Dey,
Steven Jinks,
Nancy Decker,
Martin Daley,
John Carnright
Consumers
Power Company
Tennessee Valley
Authority, Division
of Water
Resources
New York Power
Authority
Southern Energy
California
California
Departments of
Fish and Game
and Water
Resources
American Electric
Power
Bay-Delta Fishery
Project
Title
Biological and Engineering
Evaluation of a Fine-Mesh
Screen Intake for Big Bend
Station Unit 4
Evaluation of Variable Pumping
Rates as a Means to Reduce
Entrainment Mortalities
1991 Annual Report Describing
Performance of Deterrent Net
System at JR Whiting
A Biological Evaluation of Fish
Handling Components of a
Water Intake Screen Designed
to Protect Larval Fish
Conditional Entrainment
Mortality Rates for Seven Taxa
of Fish at Water Intakes on the
Hudson River
Best Technology Available 1999
Technical Report for the
Pittsburg and Contra Costa
Power Plants
A Fish Protection Facility for the
Proposed Peripheral Canal
Philip Sporn Plant
Demonstration Project for PL
92-500 Section 31 6(b)
Roaring River Slough Fish
Screen Evaluation, 1984
Date"
1980
2003
1992
1979
1998
2000
1981
1980
1984
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes
Used?
No
No
No
Reasons for Use/Non-Use
Interim report of data originating
from a controlled study involving
a prototype. While technology
involved dual flow traveling
screens with baskets and
mortality data were reported at 0
and 48 hours post-impingement,
the technology is not BTA. It is
also not clear whether the 48-
hour data correspond to the same
organisms as evaluated at 0
hours.
No impingement data
No mortality data. Technology is
not modified traveling screens.
No impingement data
No impingement data
No impingement data
No impingement data
No mortality data. Technology is
not modified traveling screens.
No impingement data
Entrainment Data
Pre-
sent?
Yes
Yes
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
No entrainment data
Data for only one species
reported. Coarse mesh screens
used. No "front" data.
No entrainment data
No entrainment data
Estimated mortality data only. No
information reported on
technology.
No entrainment data
No entrainment data
No fine mesh screens
considered. No "front" data.
No information on screen size
given.
-------
Exhibit 11A-1: (Continued)
ID
115
116
118
119
122
123
124
125
126
DCN
DON 5-4008
DCN 10-5491
DCN 10-5492
DCN 10-5493
DCN 5-4404
DCN 6-5050
DCN 4-1 51 6
DCN 6-5046E
Authors
Stephen B.
Weisburg, William
H. Burton, Eric A.
Ross, Fred
Jacobs
HDR/LMS
Edward Taft,
Thomas Horst,
and John Dowling
- Stone and
Webster
Engineering
Corporation
E. P. Taft - Stone
and Webster
Environmental
Services
Versar, Inc.
U.S. NRC, Office
of Standards
Development
NJ DEP;
Prepared by
ESSA
Technologies
David Baily, Jules
Loos, Ann
Wearmouth, Pat
Langley, Elgin
Perry
Title
The Effects of Screen Slot Size,
Screen Diameter, and Through-
Slot Velocity on Entrainment of
Estuarine Ichthyoplankton
through Wedgewire Screens
Salem NJPDES Permit
Renewal Application February
2006
Biological Evaluation of a Fine-
Mesh Traveling Screen for
Protecting Organisms
Evaluation of Strobe Lights for
Fish Diversion at the York
Haven Hydroelectric project
Evaluation of the 31 6 Status of
Delaware Facilities with Cooling
Water Discharges
U.S. Nuclear Regulatory
Commission Regulatory Guide
Review of Portions of NJPDES
Renewal Application for the
PSE&G salem Generating
Station
Effectiveness, Operation and
Maintenance, and Costs of a
Barrier Net System for
Impingement Reduction at the
Chalk Point Generating Station
Date"
1984
2006
1981
1992
1990
1975
2000
2003
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Used?
No
No
No
Reasons for Use/Non-Use
No impingement data
No impingement data
Data originate from a controlled
study involving a prototype.
While technology involved dual
flow traveling screens with
baskets and mortality data were
reported at 0 and 48 hours post-
impingement, it is not clear
whether the 48-hour data
correspond to the same
organisms as evaluated at 0
hours.
No impingement data.
(Technology focuses on
avoidance/deterrence involving
strobe lights, sound.)
No impingement data
No impingement data
Non-BTA technology used (sound
deterrent)
No mortality data. Focus is on
evaluating barrier net
effectiveness.
Entrainment Data
Pre-
sent?
Yes*
Used?
Yes
Reasons for Use/Non-Use
Entrainment density data
reported for samples collected
from "behind" screens of various
mesh sizes (1-3 mm) and from
samples collected from an open
port ("front").
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
127
128
129
130
131
132
133
134
DCN
DON 6-5046F
DCN 6-5043
DCN 6-5046D
DCN 5-4361
DCN 5-4384
DCN 5-4358
DCN 5-4386
DCN 5-4399
Authors
Steven M. Jinks,
Nancy Decker,
William Dey, John
Young, Douglas
Dixon
David Bruzek,
Selvakumaran
Mahadevan, Mote
Marine
Laboratory
Mark F.
Strickland, James
E. Mudge
J. Boreman, L.W.
Barnthouse, D.S.
Vaughan, C.P.
Goodyear, S.W.
Christensen, K.D.
Kumar, B.L. Kirk,
W. Van Winkle
Dr. Y.G. Mussalli
et al (Stone &
Webster),
M.P.McNamera et
al (NUSCO)
Douglas Hjorth,
Fred Winchell,
John Downing,
Don Cochran,
Rose Perry
(Stone &
Webster)
Lawler Matusky &
Skeller Engineers
Tenera
Environmental
Services
Title
A Review of Impingement
Survival Studies at Steam-
Electric Power Stations
Fine Mesh Screen Survivability
Study Big Bend Unit 4 Tampa
Bay Electric Company
Selection and Design of Wedge
Wire Screens and a Fixed-
Panel Aquatic Filter Barrier
System to Reduce Impingement
and Entrainment at a Cooling
Water Intake Structure on the
Hudson River
The Impact of Entrainment and
Impingement on Fish
Populations in the Hudson River
Estuary for Six Fish Populations
Inhabiting the Hudson River
Estuary
Feasibility Study of Cooling
Water System Alternatives to
Reduce Winter Flounder Larval
Entrainment at Millstone Units
1 , 2, and 3
Preliminary Assessment of Fish
Entrainment at Hydropower
Projects - A Report on Studies
and Protective Measures
Field Testing of Behavioral
Barriers for Fish Exclusion at
Cooling-Water Intake Systems
Moss Landing Power Plant
Modernization Project 31 6(b)
Resource Assessment
Date"
Unk.
1986
2003
1982
1993
1995
1988
2000
Impingement Data
Pre-
sent?
Yes
Yes
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
Summary report. While some
data are provided for Ristroph
screens, holding time is either
uncertain or 96 hours post-
impingement.
Non-BTA technology (traveling
screens not specified)
No impingement data
No impingement data
No impingement data
No impingement data
No mortality data. Technology is
non-BTA (various behavioral
barriers).
Mortality considered only for 4
minutes holding time. Data given
for one species (striped bass).
Entrainment Data
Pre-
sent?
Yes*
Yes
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
No entrainment data
Focus is on entrainment mortality
as estimated for several facilities.
Technologies do not include fine-
mesh screens.
Estimated counts only. Coarse
mesh screens used. No "front"
data. Data given for one species
(winter flounder).
Report on construction of a
database containing data from
multiple facilities. Entrainment
rates are given (per unit time) at
a high level. No information on
technologies used was given and
were not expected to include fine-
mesh screens.
No entrainment data
Coarse mesh screens used.
-------
Exhibit 11A-1: (Continued)
ID
135
136
137
138
139
140
141
142
143
DCN
DON 5-4400
DCN 5-431 7
DCN 6-501 6
DCN 6-5046H
DCN 6-5046P
DCN 6-5046Q
DCN 5-4363
DCN 5-4366
DCN 5-4369
Authors
Tenera
Environmental
Services
Lawler, Matusky
& Skelly
Engineers
Marine Resource
Advisory Council
Isabel C. Johnson
and Steve Moser
J R Nedwell,
AWH Turnpenny,
and D Lambert
E. P. Taft,
Thomas C. Cook,
Jonathan L.
Black, Nathaniel
Olkien
R. H. Gray, T. L.
Page, E. G. Wolf,
M. J. Schneider
(Batelle)
Thomas J.
Edwards, William
H. Hunt, Larry E.
Miller, James J.
Sevic
Stone & Webster
Engineering
Corporation
Title
Diablo Canyon Power Plant
316(b) Demonstration Report
Intake Debris Screen
Postimpingement Survival
Evaluation Study: Roseton
Generating Station 1990
(Portion of Chapter 3 and
selected tables from Chapter 5)
Effects of Power Plants on
Hudson River Fish
Fish Return System Efficacy
and Impingement Monitoring
Studies for JEA's Northside
Generating System
Objective Design of Acoustic
Fish Deterrent Systems
Fish Protection Technologies
for Existing Cooling Water
Intake Structures and their
Costs
A Study of Fish Impingement
and Screen Passage at Hanford
Generation Project - A Progress
Report
An Evaluation of the
Impingement of Fishes at Four
Duke Power Company Steam
Generating Facilities
Final Report: Biological
Evaluation of a Modified
Traveling Screen Mystic
Station - Unit No. 7
Date"
2000
1991
2000
Unk.
2003
2003
1975
1976
1981
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Yes
Yes*
Used?
No
No
No
No
No
Reasons for Use/Non-Use
While impingement is noted in the
report, no impingement data are
summarized in tables. Traveling
screens were not modified.
While impingement mortality was
reported up to 48 hours post-
impingement for dual-flow
traveling screens with screen
baskets, there is limited
information to confirm that the
fish return system is BTA.
No impingement data
Impingement mortality data were
reported either immediate (0 hr.)
or "long term" (at least 72 hours)
post-impingement.
No impingement data
No impingement data
No impingement mortality data
reported. Traveling screens are
not modified.
No impingement mortality data
reported. Traveling screens are
not modified.
While some impingement
mortality data were reported for
modified traveling screens at 0
and 24 hours post-impingement,
information was not sufficient to
determine cumulative mortality by
24 hours. Some question on
whether technology is BTA.
Entrainment Data
Pre-
sent?
Yes
Yes
Used?
No
No
Reasons for Use/Non-Use
Coarse mesh screens used.
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
Some limited "passage to behind
screens" entrainment data were
reported with impingement data,
but no "front" data. Screens are
coarse mesh.
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
144
145
146
147
148
149
151
152
153
154
155
156
DCN
DON 5-4370
DCN 5-4372
DCN 6-5057
DCN 5-4308
DCN 5-4309
DCN 5-4310
DCN 5-431 5
DCN 5-431 6
DCN 10-5523
DCN 10-5524
DCN 10-5525
DCN 10-5526
Authors
United Engineers
& Constructors
Florida Power &
Light Company
American Society
of Civil Engineers
Ronald J. Decoto
Brian D. Quevlog
Randall L. Brown,
Dan B.
Odenweller
AWH Turnpenny,
PA Henderson
AWH
Turnpenny, K P
Thatcher, R
Wood, P H
Loeffelman
Tom M. Pankratz
Stone & Webster
Engineering
Corporation
Malcolm E. Brown
Lawrence W.
Smith, David E.
Ferguson
Title
Edgar Energy Park Clean Water
Act Sections 316(a) & 316(b)
Demonstration
Assessment of the Impacts of
the St Lucie Nuclear Generating
Plant on Sea Turtle Species
Found in the Inshore Waters of
Florida
Design of Water Intake
Structures for Fish Protection
1974 Evaluation of the Glenn-
Colusa Irrigation District Fish
Screen
An Inventory of Selected Fish
Screens in California
A Fish Protection Facility for the
Prposed Peripheral Canal
Design and Testing
Specification for a Deterrent
Bubble Barrier for Heysham
Power Stations 1 & 2
Experiments on the Use of
Sound as a Fish Deterrent
Screening Equipment
Handbook
Assessment of Downstream
Migrant Fish Protection
Technologies for Hydroelectric
Application
Progress Report on Profile Wire
Intake Screen Testing Forked
River, New Jersey
Cleaning and Clogging Tests of
Passive Screens in the
Sacramento River, California
Date"
1990
1995
1982
1978
1981
1981
1992
1993
1995
1986
1979
1979
Impingement Data
Pre-
sent?
Yes*
Used?
No
Reasons for Use/Non-Use
No impingement data
No impingement data. (Only
turtle species were considered.)
Impingement mortality data were
accompanied by only limited
information on technology used.
No impingement data (bypass
data were reported instead).
No impingement data
No impingement data
No impingement data
No impingement data
No impingement data
No impingement data.
No impingement data.
No impingement data.
Entrainment Data
Pre-
sent?
Yes
Used?
No
Reasons for Use/Non-Use
Estimated entrainment counts are
based on samples taken from the
water body. No "front" sample
data were reported. Coarse
mesh screens used.
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
157
158
159
160
162
163
164
165
166
167
DCN
DON 10-5527
DCN 10-5528
DCN 10-5529
DCN 10-5530
DCN 10-5531
DCN 10-5532
DCN 10-5533
DCN 10-5534
DCN 10-5535
DCN 10-5536
Authors
T. E. Crumlish
W. S. Lifton
Brian N. Hanson
James M.
Wiersema,
Dorothy Hogg,
and Lowell J. Eck
R. W. Crippen
Lawrence R.
King, Jay B.
Hutchison Jr.,
Thomas G.
Huggins
Thomas R.
Thathom, David
L. Thomas,
Gerald J. Miller
T. L. Page, D. A.
Neitzel, R. H.
Gray
Yusuf G. Mussalli,
Edward P. Taft,
Peter Hoffman
Brian N. Hanson,
Wiliam H. Bason,
Barry E. Beitz,
Kevin E. Charles
Title
Extended Abstract -
Engineering Aspects of Screen
Testing on the St. Johns River,
Palatka, Fla.
Extended Abstract - Biological
Aspects of the Screen Testing
of the St Johns River, Palatka,
Fla.
Studies of Three Cylindrical
Profile-wire Screens Mounted
Parallel to Flow Direction
Biofouling Studies in
Gaslveston Bay - Biological
Aspects - Abstract
Impacts of Three Types of
Power Generating Discharge
Systems on Entrained Plankton
Impingement Survival Studies
on White Perch, Striped Bass,
and Atlantic Tomcod at Three
Hudson River Power Plants
Survival of Fishes and
Macroinvertibrates Impinged at
Oyster Creek Generating
Station
Comparative Fish Impingement
at Two Adjacent Water Intakes
on the Mid-Columbia River
Engineering Implications of New
Fish Screening Concepts
A Practical Intake Screen which
Substantially Reduces the
Entrainment and Impingementof
Early Life Stages of Fish
Date"
1979
1979
1979
1979
1977
1977
1977
1977
1977
1977
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
No impingement data.
No impingement data.
No impingement data
No impingement data.
No impingement data.
Only immediate and >48 hour
post-impingement mortality
reported.
Traveling screens are not
modified.
Traveling screens are not
modified.
No impingement data.
Laboratory study
Entrainment Data
Pre-
sent?
Yes
Yes*
Used?
No
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
Laboratory study.
No entrainment data
No entrainment data (only
plankton considered in a
controlled study).
No entrainment data
No entrainment data
No entrainment data
No entrainment data
Laboratory study
-------
Exhibit 11A-1: (Continued)
ID
168
169
206-A
170
171
173
174
175
176
177
DCN
DON 5-4379
DCN 5-4379
DCN 5-4379
DCN 5-4379
DCN 5-4350
DCN 7-4561
DCN 7-4530
DCN 10-5544
DCN 10-5545
Authors
L.S. Murray and
T.S. Jinnette
D.A.
Tomljanovich,
J.H. Heuer, and
C.W. Voigtlander
J.H. Heuer and
D.A.
Tomljanovich
B.N. Hanson,
W.H. Bason, B.E.
Beitz, and K.E.
Charles
EA Science and
Technology
Acres
International
Corporation
Dames and
Moore
Alliant Energy
B.D. Gieseand
K.N. Mueller
Title
Survival of Dominant Estuarine
Organisms Impinged on Fine-
Mesh Traveling Screens at the
Barney M. Davis Power Station
Investigations on the Protection
of Fish Larvae at Water Intakes
Using Fine-Mesh Screening
A Study on the Protection of
Fish Larvae at Water Intakes
Using Wedge-Wire Screens
Practicality of Profile-Wire
Screen in Reducing
Entrainment and Impingement
Results of entrainment and
impingement monitoring studies
at the Westchester RESCO
facility, Peekskill, New York
Report on fish entrainment
study: November 1993 to
November 1994, Glens Falls
Seminole Plant Units 1&2 31 6b
Study Report
Final Environmental Impact
Statement: Ottumwa
Generating Station
Section III Prairie Island Nuclear
Generating Plant Environmental
Monitoring Report - 2002
Annual Report
Date"
1977
1977
1987
1977
1987
1995
1979
1978
2002
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Yes
Yes
Yes
Used?
No
No
No
No
No
No
Reasons for Use/Non-Use
While impingement mortality was
documented for Passavant
center-flow traveling screens that
feature screening baskets for
retaining screened material, only
immediate mortality was
observed (for up to 10-15 minutes
post-impingement).
While percent impingement
mortality was documented, this is
a laboratory study that did not
involve evaluation of modified
traveling screens.
Laboratory study. "Bypassed"
data are reported rather than
impingement data.
Laboratory study.
Only percentages of impinged
data represented by certain
species, and total fish impinged,
were reported. No impingement
mortality reported.
No impingement data
Technology involved fixed
screens rather than traveling
screens. No impingement
mortality data reported.
No impingement data.
No impingement mortality data.
Traveling screens are not
modified.
Entrainment Data
Pre-
sent?
Yes
Yes
Yes
Yes
Yes*
Used?
No
No
No
No
Yes
Reasons for Use/Non-Use
No entrainment data
Laboratory study. "Retained"
data are reported, implying that
entrainment data may be
combined with impingement data.
Laboratory study. "Bypassed"
(avoidance) data are reported
rather than entrainment data.
Laboratory study
Only percentages of entrained
data represented by certain
species, and total fish entrained,
were reported. No "front" data
reported.
Use of behavioral systems with
no clear information given on
screen mesh size. Data originate
from a controlled study and report
entrainment mortality.
Estimated numbers of entrainable
fish reported behind 1 and 2 mm
mesh screens, and through open
pipe ("front").
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
178
179
180
181
182
183
184
185
186
187
188
DCN
DON 10-5546
DCN 10-5547
DCN 10-5548
DCN 8-4501
DCN 10-5550
DCN 8-451 3
DCN 7-4507
DCN 7-4508
DCN 10-5554
DCN 7-451 2
Authors
Tennessee Valley
Authority
Tennessee Valley
Authority
Tennessee Valley
Authority
Normandeau
Associates, Inc.
Industrial Bio-Test
Laboratories, Inc.
Carolina Power &
Light Company
Wisconsin
Electric Power
Company
Wisconsin
Electric Power
Company
Delmarva Power
& Light Company
Applied Biology,
Inc.
Title
Biological Effects of Intake
Browns Ferry Nuclear Vol 1
Summary of the Evaluation of
the Browns Ferry Nuclear Plant
Intake Structure
316(a)and316(b)
Demonstration Cumberland
Steam Plant - Volume 5
316(a)and316)b)
Demonstration: John Sevier
Steam Plant
Impingement and Entrainment
at the Cooling Water Intake
Structure of the Delaware City
Refinery, April 1998-March
2000
A Baseline/Predictive
Environmental Investigation of
Lake Wylie
Brunswick Steam Electric Plant
Cape Fear Studies Interpretive
Report
Oak Creek Power Plant Final
Report Intake Monitoring
Studies
Port Washington Power Plant
Final Report Intake Monitoring
Studies
Vienna Power Station
Prediction of Aquatic Impacts of
the Proposed Cooling Water
Intake A Section 31 6(b)
Demonstration
Impingement Monitoring
Program South Carolina Public
Service Authority Winyah Plant
Final Report
Date"
1978
1977
1977
2000
1974
1985
1976
1976
1982
1977
Impingement Data
Pre-
sent?
Yes
Yes
Yes
Yes
Yes
Used?
No
No
No
No
No
Reasons for Use/Non-Use
No impingement data.
No impingement data
No impingement data
No impingement mortality data.
Traveling screens are not
modified.
No impingement data.
Impingement mortality measured
at 0 and 96 hours post-
impingement only. Traveling
screen technology not modified.
No impingement mortality data.
Traveling screens are not
modified.
No impingement mortality data.
Traveling screens are not
modified.
No impingement data.
No impingement mortality data.
Traveling screens are not
modified.
Entrainment Data
Pre-
sent?
Yes*
Yes
Yes
Yes*
Yes
Yes
Yes*
Used?
No
No
No
Yes
No
No
No
Reasons for Use/Non-Use
No entrainment data
Coarse mesh size screens used.
No information on screen mesh
size.
Coarse mesh size screens. No
"front" density data reported.
No entrainment data that
corresponds to organism
densities. No information on
screen mesh size.
Densities of organisms entrained
through 1 mm screens ("behind")
and 9.5 mm screens ("front").
Coarse mesh size screens. Only
total entrainment estimates
reported.
Coarse mesh size screens. Only
total entrainment estimates
reported.
While "front" and "behind" sample
data are available for fine-mesh
screens, intersample
contamination between screened
and unscreened samples
prevented their use.
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
189
190
191
192
193
201
194
195
DCN
DON 7-451 3
DCN 10-5557
DCN 10-6806
DCN 10-6801
DCN 10-6813
DCN 10-6804
DCN 10-6802
Authors
Geo-Marine, Inc.
Equitable
Environmental
Health, Inc.
EPRI
EPRI
EPRI
EPRI
EPRI
Title
31 6b Demonstration Report for
the Arkansas Eastman Plant on
the White River
Meramec Power Plant
Entrainment and Impingement
Effects on Biological
Populations of the Mississippi
River
Field evaluation of wedgewire
screens for protecting early life
stages at cooling water intake
structures: Chesapeake Bay
studies
Laboratory evaluation of
modified Ristroph traveling
screens for protecting fish at
cooling water intakes
Fish Protection at Cooling
Water Intake Structures: A
Technical Reference Manual
Design considerations and
specifications for fish barrier net
deployment at cooling water
intake structures
Laboratory evaluation of fine-
mesh traveling water screens
for protecting early life stages of
fish at cooling water intakes
Date"
1981
1976
2006
2006
2007
2006
2008
Impingement Data
Pre-
sent?
Yes
Yes*
Yes*
Yes*
Used?
No
No
Yes
No
Reasons for Use/Non-Use
No impingement count or
mortality data reported. Limited
information is given on
technology used.
No impingement mortality data.
Traveling screens are not
modified.
No impingement data
Laboratory study
This is a summary report of data
from multiple studies. Chapter 2
contains impingement data, some
of which originate from other
reviewed reports. Data appear
from Dunkirk and Huntley that
were utilized in the impingement
mortality limitations.
Impingement mortality data from
other sources were not used due
to non-BTA technology or
corresponding to 0 or >48 hours
post-impingement.
No impingement data.
Laboratory study
Entrainment Data
Pre-
sent?
Yes
Yes
Yes*
Yes*
Used?
No
No
Yes
Yes
Reasons for Use/Non-Use
No information given on mesh
size of traveling screens
(expected to be coarse mesh).
"Behind" entrainment data
collected only.
Coarse mesh size only.
Entrainment data did not include
eggs or larvae.
Source of "front" and "behind"
entrainment density data from
test barge in the Chesapeake
Bay, which were used in
determining the proposed
entrainment design standard.
No entrainment data
This is a summary report of data
from multiple studies. Chapter 5
contains entrainment data from
wedgewire screens. This report
was the source of "front" and
"behind" entrainment density data
from test barge studies in the
Portage and Sakkonet Rivers and
from Oyster Creek, which were
used in determining the proposed
entrainment design standard.
Other entrainment data were not
used due to not reporting results
for both "front" and "behind"
samples.
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
196
197
198
199
200
202
203
204
205
DCN
DON 10-6814
DCN 10-6970
DCN 10-6971
DCN 4-1 682
DCN 10-5567
DCN 10-5568
DCN 10-5569
DCN 10-5570
DCN 10-5571
Authors
EPRI
EPRI
EPRI
Robert W. Davis,
John A.
Matousek,
Michael J. Skelly,
and Milton R.
Anderson
Applied Science
Associates
S.L Blanton, D.A.
Neitzel, and C.S.
Abernethy
W. Bengeyfield
M.D. Bowen, S.M.
Siegfried, C.R.
Listen, A.J. Hess
and C.A. Karp
D.L.Breitburg and
T.A.Thoman
Title
Latent impingement mortality
assessment of the Geiger Multi-
Disc screening system at
Potomac River Generating
Station
The role of temperature and
nutritional status in
impingement of clupeid fish
species
Cooling Water Intake Structure
Area-of-lnfluence Evaluations
for Ohio River Ecological
Research Program Facilities
Biological Evaluation of Brayton
Point Station Unit 4, Angled
Screen Intake
Ichthyoplankton Monitoring
Study Deployment of a
Gunderboom System at Lovett
Generating Station Unit 3, 1998
Washington Phase II Fish
Diversion Screen Evaluations in
the Yakima River Basin, 1997
Evaluation of a Temporary
Screen to Divert Fish at
Puntledge Generating Station
Fish Collections and Secondary
Louver Efficiency at the Tracy
Fish Collection Facility
Calvert Cliffs Nuclear Power
Plant Finfish Survival Study
Date"
2007
2008
2007
1988
1999
1998
1992
1998
1986
Impingement Data
Pre-
sent?
Yes*
Yes
Yes*
Used?
No
No
No
Reasons for Use/Non-Use
Technology not classified as
BTA. Concern about data quality
(influence of weather events).
No impingement data.
No impingement data.
Although impingement mortality is
reported at 48 hours post-
impingement and the technology
is referred to as "modified intake
screens," fish are removed from
screens using spraywash into a
fish trough.
No impingement data.
No impingement data. Non-BTA
screen technology used to
promote fish diversion.
No impingement data. Evaluation
of temporary barrier net.
No impingement data.
Assessed technologies included
dual-speed, Beauderey, and
control traveling screens.
Impingement mortality data
appear to represent only
immediate post-impingement.
Entrainment Data
Pre-
sent?
Yes
Used?
No
Reasons for Use/Non-Use
No entrainment data
No entrainment data
No entrainment data
No entrainment data
Used Gunderboom system rather
than fine mesh screen
technology. (Same data found in
other Gunderboom reports.)
No entrainment data
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
206
207
208
210
211
212
213
214
215
DCN
DON 10-5572
DCN 10-5573
DCN 10-5574
DCN 7-4504
DCN 9-4664
DCN 10-5577
DCN 10-5578
DCN 10-5579
DCN 7-451 1
Authors
V. Brueggemeyer,
D.Cowdrick, K.
Durrell, S.
Mahadevan and
D. Bruzek
Beak Consultants
Incorporated
Carolina Power
and Light
Company
NALCO
Environmental
Sciences
Wapora Inc
Hugh Barwick
J. P. Buchanan,
D.L Dycus, H.R.
Gwinner, and
J.M. Roberts, Jr.
Stone and
Webster
Engineering
Corporation,
Boston, MA
Wapora
Title
Full-scale Operational
Demonstration of Fine Mesh
Screens at Power Plant Intakes
Dunkirk Station Biological
Studies
Brunswick Steam Electric Plant:
1984 Biological Monitoring
Report
Dean H Mitchell Station 316(b)
Demonstration
Studies of screen impingement
and egg and fry entrainment at
the Joppa Illinois Electric
Generating Station
Fish Impingement at Oconee
Nuclear Station
Aquatic Environmental
Conditions in Chickamauga
Reservoir During Operation of
Sequoyah Nuclear Plant, Sixth
Annual Report
Studies to Alleviate Potential
Fish Entrapment Problems
(Volume 1 of 2)
316 (a) and (b) Studies on the
Grand River
Date"
1998
1988
1985
1976
1976
1990
1987
1977
1977
Impingement Data
Pre-
sent?
Yes*
Yes*
Yes*
Yes
Yes
Yes
Yes
Used?
No
No
No
No
No
No
No
Reasons for Use/Non-Use
Mortality data are reported only
immediately following
impingement. Technology does
not appear to be BTA.
Impingement mortality data
correspond to Beauderey
traveling screens with no fish
return system, and reported only
at 0 and 96 hours post-
impingement.
Traveling screen technology not
modified.
Impingement mortality not
reported. Traveling screen
technology not modified.
Impingement mortality not
reported. Traveling screen
technology not modified.
Impingement mortality not
reported. Modified traveling
screens not used.
No impingement data.
No impingement data associated
with field studies.
No impingement mortality data
reported. No information given
on technology used at the
specified plants.
Entrainment Data
Pre-
sent?
Yes
Yes
Yes
Yes
Yes
Used?
No
Yes
No
No
No
Reasons for Use/Non-Use
No entrainment data (focus was
on engineering evaluations of
screening efficiencies)
Densities of organisms that would
pass through 3.2 mm mesh size
screens were estimated from
samples collected upstream of
the screens. No densities
representing the "front" of intake
were reported.
Densities of organisms entrained
through 1 mm screens ("behind")
and 9.5 mm screens ("front").
Coarse mesh screens used.
Only "behind" sample data
reported.
No information given on screen
mesh size.
No entrainment data
No entrainment data
No entrainment data
Fish counts obtained only from
samples collected in front of the
intakes and estimated to be
entrained. No information given
on technology used at the
specified plants.
-------
Exhibit 11A-1: (Continued)
ID
216
217
218
219
220
221
200-A
DCN
DON 7-0009
DCN 7-4520
DCN 7-4505
DCN 7-451 6
DCN 7-4557
DCN 10-5586
DCN 10-5587
Authors
Tetra Tech
Western Illinois
Power
Cooperative
Foster Wheeler
Environmental
Corporation
Carolina Power
and Light
EA Science
Alden Rsearch
Laboratory and
Stone & Webster
Engineering
Corporation
Stone & Webster
Engineering
Corporation
Title
Small facility ichthyoplankton
entrainment sampling for the
development of the 316(b)
Phase III Rule for cooling water
intake structures
Fish impingement studies at
Pearl Station-February 1977-
January 1978
Comanche Peak Steam Electric
Station Units 1 and 2 31 6 (b)
Demonstration
HB Robinson Steam Electric
Plant 316 Demonstration Study
Bayway Refinery impingement
and entrainment study for
31 6(b) of the Clean Water Act
Laboratory Evaluation of Fish
Protective Devices at Intakes
Alternative Intake Designs for
Reducing Fish Losses, Mystic
Station - Unit 7
Date"
2004
1978
1995
1976
1995
1981
1979
Impingement Data
Pre-
sent?
Yes
Yes
Yes
Yes
Yes
Used?
No
No
No
No
No
Reasons for Use/Non-Use
No impingement data.
Impingement mortality was not
assessed. No information given
on the technology used.
Traveling screens are not
modified. No impingement
mortality results reported.
Traveling screens are not
modified. No impingement
mortality results reported.
Traveling screens are not
modified. No impingement
mortality results reported.
No impingement data. Several
technologies were evaluated
under laboratory conditions,
including fish diversion and
bypass, and behavioral barriers,
but not modified traveling
screens. For angled screens,
mortality associated with
diversion was reported only at 96
hours.
While this report documents the
findings of several studies
assessing impingement mortality
associated with modified traveling
screens, mortality was assessed
either at impingement (or within
15 minutes of impingement) or
>48 hours post-impingement in
each case.
Entrainment Data
Pre-
sent?
Yes
Yes
Yes
Yes
Used?
No
No
No
No
Reasons for Use/Non-Use
Entrainment densities reported
for several sites at the nearfield
("front") and within the intake
prior to the intake pumps
("behind") , but no information is
given on technology (e.g., screen
size).
No entrainment data
Coarse mesh screens were
utilized. While "front" samples
appeared to have been collected,
their data were not summarized.
Coarse mesh screens were
utilized. No "front" samples
reported.
Coarse mesh screens were
utilized. No "front" samples
reported.
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
201 -A
202-A
203-A
204-A
205-A
207-A
208-A
209-A
DCN
DON 10-5588
DCN 10-5589
DCN 10-5590
DCN 10-5591
DCN 10-5592
DCN 10-5593
DCN 10-5594
DCN 10-5595
Authors
Donald E. Clark
and Douglas P.
Cramer
D.P. Cramer
P.M Cumbie and
J.B. Banks
Stone & Webster
Environmental
Services
Texas
Instruments
Incorporated
Larry E. Week,
Victor C. Bird,
and R. Eugene
Geary
Michael Wert
Fred Winchell,
Ned Taft, Tom
Cook and Charles
Sullivan
Title
Evaluation of the Downstream
Migrant Bypass System - T.W.
Sullivan Plant, Willamette Falls
Evaluation of a Louver
Guidance System and Eicher
Screen for Fish Protection at
the T.W. Sullivan Plant in
Oregon
Protection of Aquatic Life in
Design and Operation of the
Cope Station Water Intake and
Discharge Structures
Proposal for Services to
Perform 1992 Blueback Herring
Environmetnal Studies at the
Little Falls Hydroelectric Project,
Little Falls, New York
Initial and Extended Survival of
Fish Collected from a Fine
Mesh Continuously Operating
Traveling Screen at the Indain
Point Generating Station
Effects of Passing Juvenile
Steelhead, Chinook Salmon,
and Coho Salmon Through an
Archimedes' Screw Pump
Hydraulic Model Evaluation of
the Eicher Passive Pressure
Screen Fish Bypass System
Research Update on the Eicher
Screen at Elwha Dam
Date"
1993
1997
1997
1991
1978
1989
1988
1993
Impingement Data
Pre-
sent?
Yes
Yes
Used?
No
No
Reasons for Use/Non-Use
No impingement data - mortality
data (>48 hour holding time) were
associated with negotiating a
downstream migrant bypass
system rather than screen
impingement.
No impingement data - 48-hour
mortality data were associated
with negotiating a downstream
migrant bypass system rather
than screen impingement.
No impingement data.
No impingement data.
While percent impingement
mortality associated with Ristroph
traveling screens are reported,
more information is needed to
determine cumulative mortality at
a certain point (e.g., 36 hours)
post-impingement.
No impingement data. This
report documents the outcome of
controlled experiments of screw
pump pass-through.
Laboratory study of Eicher
screens rather than modified
traveling screens. Impingement
mortality evaluated at 72 hours
post-impingement only.
"Passage survival" after 96 hours
was reported rather than screen
impingement survival or mortality.
Entrainment Data
Pre-
sent?
Used?
Reasons for Use/Non-Use
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
No entrainment data
-------
Exhibit 11A-1: (Continued)
ID
210-A
DCN
DON 10-5596
DCN 6-5004B
Authors
Thomas Plants,
Michael
Feldhausen,
Dennis Olsen and
David Michaud
EPRI
Title
Maintenance Requirements of a
Fish Barrier Net System
Laboratory Evaluation of
Wedgewire Screens for
Protecting Early Life Stages of
Fish at Cooling Water Intakes
Date"
1997
2003
Impingement Data
Pre-
sent?
Yes
Used?
No
Reasons for Use/Non-Use
No impingement data. Focus
was on assessing the
functionality and performance
(biofouling) of a prototype barrier
net system.
Laboratory study. No
impingement mortality data
reported.
Entrainment Data
Pre-
sent?
Yes
Used?
No
Reasons for Use/Non-Use
No entrainment data
Laboratory study
* Some of the impingement or entrainment data reported in this document (counts and/or mortality percentages) were entered in EPA's performance study database and were summarized
within a meta-analysis.
a Unknown (not specified).
-------
Chapter 11: Appendix A
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11A-2: List of Documents and Facilities with Impingement Mortality Data
(counts and/or percentages) in EPA's Performance Study Database
Document ID
17
18
38
43
43
44
46
46
46
46
49
51
54
60
62
64
65
66
73
76
78
78
85
103
106
108
118
125
126
136
138
138
141
143
146
163
163
164
168
169
171
192
193
193
193
Facility Name
Hinkley Point Power Station
Moss Landing
Bowline Point Generating Station
Barney Davis Power Station
Surry Power Station
Dunkirk Steam Station
Brayton Point Generating Station Unit 4
Calvert Cliffs Nuclear Generating Station
Dunkirk Steam Station
Indian Point Generating Station
Chalk Point Generating Station
Huntley Steam Station
Arthur Kill Generating Station
Quad Cities Generating Station
Oyster Creek Nuclear Generating Station
Somerset Generating Station
Calvert Cliffs Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Le Blayais
Heysham Power Station
Sizewell A and B
Various Coastal Stations in the U.K.
Salem Generating Station
Monroe Power Plant
Big Bend Power Station
JR Whiting
Big Bend Power Station
Salem Generating Station
Chalk Point Generating Station
Roseton Generating Station
JEA Northside Generating System
Roseton Generating Station
Hanford Generating Project
Mystic Generating Station
No facility specified
Bowline Point Generating Station
Roseton Generating Station
Oyster Creek Nuclear Generating Station
Barney Davis Power Station
TVA laboratory
Test laboratory
Test laboratory
Arthur Kill Generating Station
Bowline Point Generating Station
Brayton Point Generating Station Unit 4
# Hours Following Impingement
Associated with Entered Mortality
Data
0
0, 96
0
0
0
0,24
0,48
0
0
0
0
0,24
24
0
0
0, 96
0
0
0
0
0
0
48
0
0
0
0, 48, 96
0
0
0
0
0
0
0, 24, 96
0
0, 96
0
0
0
0, 12,24,48
0
0,48
24
0, 96
0,48
11A-24
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix A
Exhibit 11A-2: (Continued)
Document ID
193
193
193
193
193
193
193
193
193
195
196
205
206
207
208
Facility Name
Brunswick Steam Electric Plant
Danskammer Point Generating Station
Dunkirk Steam Station
Indian Point Generating Station
Mystic Generating Station
Oswego Steam Station
Oyster Creek Nuclear Generating Station
Prairie Island Nuclear Generating Station
Salem Generating Station
Test laboratory
Potomac River
Calvert Cliffs Nuclear Generating Station
Big Bend Power Station
Dunkirk Steam Station
Brunswick Steam Electric Plant
# Hours Following Impingement
Associated with Entered Mortality
Data
0
0, 84
0
0, 96
0, 96
0
0
0
0, 18
0
48
0
0
0, 8, 24
0
Note: Documents are identified by their ID number in Exhibit 11A-1.
Exhibit 11A-3: List of Documents and Facilities with
Entrainment Density Data ("front" and "behind")
in EPA's Performance Study Database
Document ID
52
84
115
175
180
184
187
191
193
193
193
Facility Name
Big Bend Power Station
Logan Generating Plant
Test barge (Chalk Point)
Test barge (St. John's River)
Cumberland Steam Plant
Brunswick Steam Electric Plant
Vienna Power Station
Test barge (Chesapeake Bay)
Test barge (Oyster Creek)
Test barge (Portage River)
Test barge (Sakkonet River)
Note: Documents are identified by their ID number in Exhibit 11A-1.
11A-25
-------
Chapter 11: Appendix A
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11A-4: List of Documents and Facilities with Entrainment Mortality Data
(counts and/or percentages) in EPA's Performance Study Database
Document
ID
4
18
40
41
47
49
49
49
49
81
130
130
130
130
130
130
167
193
Facility Name
Anclote Power Plant
Potrero Power Plant
Lovett Generating Station
Lovett Generating Station
Green Island Hydroelectric Project
Chalk Point Generating Station
Dickerson
Morgantown
Potomac River
Pine Hydroelectric Project
Bowline Point Generating Station
Danskammer Point Generating Station
Indian Point Generating Station
Lovett Generating Station
Multiple test facilities
Roseton Generating Station
Delmarva Ecological Laboratory
Tracy Fish Collecting Facility
# Hours Following Entrainment
Associated with Entered Mortality
Data
0
0, 96
0
0
0, 24, 48
0
0
0
0
0
0,24
0,24
0,24
0,24
24
0,24
0
0
Note: Documents are identified by their ID number in Exhibit 11A-1.
11A-26
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
Appendix B to Chapter 11: Summaries and Analyses of
Data from Published Documents to Assess the
Performance of Technologies to Reduce the Impact of
Impingement or Entrainment on Aquatic Life Under
Section 316(b) of the Clean Water Act
11B.O Introduction
This appendix provides initial summaries and analyses of data obtained from 66 technical
reports and publications which document the performance of selected technologies
utilized by facilities such as power plants to reduce the adverse environmental impact
associated with operating cooling water intake structures. Of particular interest was the
impact of impingement and entrainment on the viability offish life within different age
categories. EPA reviewed documents containing data on impingement and entrainment
and placed data into a "performance study database" that reported percentages offish
killed, injured, or survived (or experienced some other positive outcome, such as
diversion). A focus was placed on percentage data as they were most likely to be directly
comparable among different documents and studies and thus could be combined for
statistical analysis. When counts offish accompanied these percentages within the
documents, or if counts were reported from which percentages could be calculated, then
EPA also entered these counts into the database.
This appendix presents a series of summaries of the performance data entered within
EPA's performance study database. These summaries are presented by technology
category, type of measure (e.g., percent mortality, mortality counts, percentage change
from baseline in mortality counts or percentage), and data classification (e.g.,
impingement, entrainment). For a given study, data values are entered for various species
and time points. Therefore, the number of values entering into a particular data summary
depends on the number of documents with relevant data and the number of species and
time points for which data are reported within these documents. For percentage and
count measures, Exhibit 11B-1 presents impingement and entrainment data summaries
for those technologies having the most data within the database (i.e., when the number of
data points exceeded 20). Key conclusions made from this exhibit include the following:
• Only a small number of studies have available performance data that are
expressed as biomass or injury, and the amount of data within these studies is
generally limited.
• Most data related to mortality and survival (or other positive outcomes) are
associated with impingement on traveling screens. Across species, time points,
and studies, percent mortality data were observed to cover the range of 0 to 100
percent among the technology categories, especially for impingement.
• Similar patterns in percent mortality following impingement are seen between
fine mesh and coarse mesh traveling screens.
HB-l
-------
Chapter 11: Appendix B
§ 316(b) Existing Facilities Proposed Rule -TDD
• When percent mortality data were available at different elapsed times following
impingement, a general increase in average percent mortality was observed as the
amount of time between impingement and observation increased. However, such
trends are hard to discern when reviewing these data summaries due to the data
being represented by different studies and test conditions.
• Percent mortality following entrainment tended to cover similar ranges among the
two technology categories in Exhibit 11B-1 having the most entrainment data.
Exhibit 11B-1. Data Summaries on Performance Measures With the Most Impingement and
Entrainment Data Values Within EPA's Performance Study Database
Technology
Category
Mor-
tality
Obs.
Time
N
Mean
Std. Dev.
Min.
Max.
Percentiles
25th
50th
75th
95th
Percent Mortality: Entrainment
Reduced Intake
Flows - Other
Traveling Screen -
Coarse Mesh
Ohr.
Ohr.
24 hr.
177
115
133
27.9
4.1
6.3
23.3
9.7
11.4
0.0
0.1
0.1
88.4
83.9
77.8
7.4
0.5
0.7
24.9
1.3
2.0
42.6
3.3
5.7
76.0
20.3
25.4
Percent Mortality: Impingement
Barriers
Fixed Screen - Fine
Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Ohr.
Ohr.
24 hr.
Ohr.
18hr.
24 hr.
48 hr.
96 hr.
Ohr.
8hr.
24 hr.
48 hr.
96 hr.
21
38
40
684
26
233
34
91
373
67
67
82
70
71.1
23.7
43.0
26.4
31.7
16.0
23.9
52.7
25.5
22.4
28.6
17.7
37.4
35.7
27.6
38.3
33.4
25.4
28.5
37.0
38.3
32.9
32.5
34.9
30.2
35.8
1.3
0.0
0.0
0.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
98.7
91.8
100.0
100.0
82.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
54.9
0.8
4.0
0.0
12.0
0.0
0.0
16.7
0.0
0.0
0.0
1.0
5.1
91.9
10.5
32.2
9.2
26.5
1.4
0.0
50.0
8.0
4.9
12.6
3.9
26.4
97.7
44.9
84.9
45.4
42.0
16.8
45.7
100.0
43.2
30.3
50.0
15.9
63.6
98.7
81.1
100.0
100.0
80.0
100.0
100.0
100.0
98.5
100.0
100.0
96.8
100.0
Percent Biomass: Impingement
Traveling Screen -
Coarse Mesh
—
48
1.4
2.6
0.0
12.8
0.1
0.3
1.2
7.6
Percent Injury: Impingement
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
—
—
20
30
28.1
7.3
15.9
9.9
5.0
0.0
64.0
34.0
12.5
0.4
28.5
2.9
38.5
9.5
57.0
29.8
Mortality Counts: Impingement
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Ohr.
24 hr.
96 hr.
Ohr.
478
130
58
125
15596
26
26
20850
122127
95
114
81984
0
0
0
0
2229859
866
848
521500
0
0
1
4
3
0
3
31
50
3
10
753
8985
111
77
113280
Survival Counts: Impingement
Fixed Screen - Fine
Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
24 hr.
Ohr.
24 hr.
96 hr.
Ohr.
8hr.
24 hr.
30
386
233
63
158
67
67
34
388
170
120
2344712
37
30
68
1329
582
376
12842622
83
67
0
0
0
0
0
0
0
342
17719
5948
2253
110000000
395
365
1
2
2
1
7
1
1
9
17
8
5
29
6
5
35
176
48
45
296
22
20
134
2383
875
420
11000000
237
213
11B-2
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
• For percent injury following impingement under traveling screen technologies,
coarse mesh screens tended to have higher injury rate than fine mesh screens.
• Mortality and survival counts are highly variable, as these counts are likely to
vary considerably across species, seasons of the year, water temperature, etc. For
these reasons, counts may not be directly comparable among different studies.
Percent mortality data were statistically analyzed using mixed model analysis of variance
techniques, with the goal of estimating average performance measure when possible for
selected age categories, seasons of the year, and elapsed times to mortality. This analysis
was applied to percent mortality data for the following technologies (as determined by
available data):
• Percent mortality following entrainment: fixed screen (fine mesh) and reduced
intake flow (other).
• Percent mortality following impingement: traveling screens (both fine and coarse
mesh).
Key findings from the statistical modeling analysis were as follows:
• Among early age categories (e.g., larvae, juvenile), the model-based estimates for
average percent mortality following entrainment under reduced intake flow
technology ranged from 27 to 34 percent. These averages did not differ
significantly at the 0.05 level.
• For impinged fish under traveling screens with either fine or coarse mesh,
estimated average percent mortality was highest in summer months, with over 50
percent mortality estimated in summer. Under fine mesh, estimated average
percent mortality also exceeded 50 percent in spring months. Differences
between seasons of the year, age categories, and elapsed time to mortality were
statistically significant at the 0.05 level.
11B.1 BACKGROUND AND OBJECTIVES
More than 1,500 industrial facilities in the United States, including steam electric power
plants, use large volumes of cooling water from lakes, rivers, estuaries or oceans to cool
their plants. Cooling water intake structures cause adverse environmental impact by
pulling large numbers offish and shellfish or their eggs into the facility's cooling system
("entrainment"). As a result, the organisms may be killed or injured by heat, physical
stress, or by chemicals used to clean the cooling system. Larger organisms may be killed
or injured by becoming trapped against screens at the front of an intake structure
("impingement").
Section 316(b) of the Clean Water Act requires that the location, design, construction and
capacity of cooling water intake structures reflect the best technology available for
minimizing adverse environmental impact such as mortality of aquatic organisms. To
minimize impingement and entrainment, facilities subject to Section 316(b) regulations
have implemented a range of different technologies. As part of the permitting process to
discharge cooling water, these facilities have collected data to demonstrate that they are
HB-3
-------
Chapter 11: Appendix B § 316(b) Existing Facilities Proposed Rule -TDD
using best technology available to minimize impingement and entrainment and issued
documents containing the results of these studies. Other organizations have issued
publications on the outcome of controlled laboratory studies to identify key factors that
impact technology performance and to determine settings for these factors that are
associated with improved performance.
In its Section 316(b) rule development effort, the U.S. Environmental Protection Agency
(EPA) gathered a series of industry documents and research publications that contain
information from studies which evaluated the performance of a range of technologies for
minimizing impingement or entrainment. In gathering this information, EPA's objective
was to review the methods used to generate data in these studies and to combine relevant
data across studies in order to produce reasonably valid statistical estimates of the overall
performance of each of the technologies.
This appendix contains statistical summaries of performance data compiled across several
reports and publications that EPA has collected, along with the results of statistical
analyses performed on these data. The primary objective of this analysis was to
characterize the distribution of data across studies and facilities, in order to better assess
the performance of different technology categories relative to their ability to minimize
impingement and entrainment of aquatic organisms.
11B.2 DOCUMENT REVIEW AND DATA ENTRY
11 B.2.1 Document receipt
For assessing performance for various technology categories, EPA considered data from
over 170 documents (See Appendix 11 A). These documents contain information on the
operation and/or performance of various forms and applications of these technologies,
typically at a specific facility or in a controlled setting such as a research laboratory. The
studies presented in these documents were performed by owners of facilities with cooling
water intake structures, organizations that represent utilities and the electric power
industry, and other research organizations. In bringing information from these
documents together to better assess performance, EPA obtained and reviewed these
documents for the presence of relevant data. Within the review process, EPA prepared a
Microsoft (MS) Access database which contained information on the following:
• The document (e.g., title, author, funding source, type of document);
• The facility(ies) represented in a document (with location, water body type, etc.);
and
• The type (category) of technology implemented at each facility within a
document.
11 B.2.2 Classifying data by technology category
When performance data for a given facility were obtained from a given document and
used in the statistical summaries and analyses, EPA determined the technology category
assigned to that data by information specified in its database of facility information
HB-4
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
("facility database") which it compiled from other data sources such as a dataset of
questionnaire responses. Fourteen possible technology categories were defined:
• Barriers (nets, micronets, Gunderboom, bars, canal diversions)
• Behavioral systems I (louvers, angled screens)
• Behavioral systems II (e.g., acoustic/sound, light, air bubbles)
• Fixed screens (coarse mesh)
• Fixed screens (fine mesh)
• Off-shore location with velocity cap
• Off-shore location (any combination other than velocity cap)
• Porous dikes, perforated pipe, substratum intakes
• Reduced intake flows - cooling towers
• Reduced intake flows - other (variable speed pumps, seasonal flows reductions,
reduced plant power output)
• Traveling screens (coarse mesh)
• Traveling screens (fine mesh)
• Velocity limit (additional screens, reduced intake velocity, T-bend)
• Other technologies.
The statistical summaries and analyses presented in this appendix focused on technology
categories having the most available data. These included fixed and traveling screens,
barriers, and behavioral systems II. While data for other technologies also existed in the
performance study database, the number of documents (or distinct studies1 within these
documents) and the amount of data was very limited, if any were encountered at all.
EPA's facility database was also the source of information on a facility's name, water
body (e.g., river, lake/reservoir, Great Lakes, ocean, estuary), and location (state).
11 B.2.3 Data acceptance criteria
While a document may present data that were acceptable for use in meeting the
document's original objectives, this does not necessarily imply that these data will meet
EPA's objective to combine data across multiple sources to better access performance of
the different technology categories. Thus, it was necessary to establish specific criteria
for accepting data from the documents for use in the statistical summaries and analyses in
this appendix. These acceptance criteria were as follows:
• The data must be associated with technologies for minimizing impingement or
entrainment that are currently viable (as recognized by EPA) for use by industries
with cooling water intake structures that are (or will be) subject to Section 316(b)
regulation.
1 In our analysis, we use the term "study" to refer to the collection of performance data within a given set of
testing conditions. A document can report performance data for one or more studies.
11B-5
-------
Chapter 11: Appendix B § 316(b) Existing Facilities Proposed Rule -TDD
• They must represent a quantitative measure (e.g., counts or percentages) that is
related to the impingement or entrainment of some life form of aquatic organisms
within cooling water intake structures under the given technology.
• The measure must be reported in one of two ways:
o On a "per available organism" basis (typically in percentage terms); or
o Accompanied by the same type of measure taken for the same species under
baseline or control conditions (i.e., in the absence of the given technology).
The last criterion was necessary to help ensure that data would be comparable when
combined across different studies and documents. Only data meeting these criteria were
considered for inclusion within the statistical summaries and analyses in this appendix.
11 B.2.4 Document review process
Reviewers of the documents had a variety of scientific backgrounds (e.g., statistics,
environmental science, chemistry, biology) and prior experience in extracting data from
technical reports and publications for statistical analysis. They were trained on the
objectives of the data analysis to be performed and the data acceptance criteria. In
performing their reviews, the reviewers completed a pre-defined "roadmap" for each
document. These roadmaps noted the presence and location of relevant data within the
document and captured key information from the documents that were related to these
data. This roadmap is given in Exhibit 11B-2. Statisticians used information recorded in
the roadmap to help determine the presence and acceptability of data for the statistical
summaries and analyses. The roadmaps also were useful in identifying when documents
did not appear to report any relevant quantitative data.
Exhibit 11B-3 lists the 66 documents from which performance study data were extracted
and utilized within the summaries and analyses presented in this appendix. Data were
entered from these documents that achieved the above acceptance criteria. For a given
document, different facilities, technologies, data types, or test conditions are specified as
separate rows within this table. See Appendix 11A for other documents that were
reviewed and determined not to contain suitable data for this effort.
HB-6
-------
Exhibit 11B-2. Roadmap Used in Identifying Relevant Performance Data for EPA's Evaluation of Technologies to Reduce
Impingement and Entrainment of Aquatic Organisms
Template for Evaluating Studies, Assessing Data Quality, and Extracting Data from Documents
Part 3: Design and Reporting
Title of document;
Tetra Tech ID:
1
JTemplate completion ID; | |
Abstractors initials. |
No relevant data in this document (check:)!
Technology (if report addresses multiple technologies):
Study Information -- Data Collected when Technology is in Place
I See worksheet for the following report for this mformatic
Here, "data" refers to measures of mortality and/or injury to aquatic organisms. Copy rows as needed to represent different data collection types or locations.
Tables/Page
Comments
Data collection period:
Frequency of data collection at a single location:
Is one objective of data collection to collect data over
multiple seasons of the year?
Is one objective of data collection to collect data in
both day and night periods?
Are data collected from multiple locations (e.g..
multiple intakes or units within a facility}?
Does the report note problems with implementing the
technology, or other problems, during data collection?
Start to
(rnm/dd/yy)
One time point
No
No
End
(mm/dd/yy)
[Multiple time points
Specify time point information '
i
|Yes
Specify seasons:
|Yes
No
No
JYes (specify details:)
JYes (specify details:}
TO
c_
C7
C7
Study Information — Availability of Baseline/Control Data for Comparing Efficacy of Technology | |_
The following list represents different types of "control" (or baseline) conditions against which a technology's efficacy couid be compared. For those
controls used in this study, specify the page numbers) where cited, and tables where detailed control data may be reported separately from data under
the given technology. (An alternative technology is NOT a control.) Provide details or explanations in the comment field.
Tables/Page Humfaersjl) Comments
Historical data (e.g., 30-year running average)
Conditions when the technology is NOT in place
Downstream conditions
Known numbers offish introduced (controlled studies)
Baseline/control was used bjjtjs^undefiried
Other (specify): | |
No baseline/control used
I See worksheet for the following reporf for this ififormattc
1
Q.
X
co
-------
Study Information — Methods and Definitions
See worksheet for the follovtmg report for this information:
ba
Method for determining ..[_
Tables/Page Numbers{1} Comments, Definitions, Species, Methods, etc.
Definition offish" # species total:
Definition of priority species #
Threatened/endangered species
Commercial species
Recreational species
Other type of priority species
Definitions offish age categories
Definitions offish size categories
Definition of other non-fish, non-plant organisms
# species |
TO
3
Q_
x"
OD
Part 3 (cont)
TetraTech ID:
[Template compietion ID:
Technology (if report addresses multiple technologies):
_ Types of Available Data Collected to Assess Efficacy _ |
Focus only on non-cost measures related to specified outcome- Copy additional rows as necessary. Ignore results presented in figures.
Include, as attachments, any copies of tables and listings of data or summary statistics referenced below. These data will be entered into the analysis database.
Outcome
Organism Type
Measure Type
Type of
Data
Reported
Units {if (if not
not count count or
Tables/
Page Numbers/
Conditions Appendices)1!) Comments
cm
CO
TO
Q.
70
C7
C7
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
11 B.2.5 Performance study database
For the statistical summary and analysis, EPA prepared a MS Access database containing
relevant performance study data from the documents listed in Exhibit 11B-3. Within this
database, each document was distinguished by a unique "document ID." A given
document could have presented performance data for different test or study conditions,
facilities, technology categories, etc. These subsets of data were distinguished within the
database by assigning a unique "study ID" to each data subset. Thus, a given document
ID was often associated with multiple study IDs within the database.
The performance study database consisted of two primary data tables:
• A table containing specific information on a particular study, such as the
document and study IDs, facility name, water body, data classification
(e.g., impingement, entrainment), technology category, and other test conditions
when specified (e.g., mesh size, velocity, water temperature, conditions when the
technology is in place, control conditions). The rows of this table were
distinguished by study ID.
• A table containing the reported performance data for a given study. Each row of
this table contained one or more performance measures for a particular species
along with other factors when they were specified (e.g., age category, dates or
seasons of data collection, water temperature, velocity, elapsed time to mortality).
Possible performance measures that could be specified in a given row of this table
included:
o Percent mortality
o Percent survival (or other positive outcome, such as retention or diversion)
o Percent biomass
o Percent injury
o Total counts or biomass of available, impinged, or entrained fish. (This
number would enter into the denominator of one of the above percentages.)
o Three types of counts of impinged or entrained fish that were classified as
either 1) dead, 2) survived, or 3) injured. (This count would enter into the
numerator of one of the above percentages.)
11B-9
-------
Exhibit 11B-3. List of Documents Represented in the Performance Study Database
Doc.
ID
4
17
18
38
40
41
42
43
Document Title
Zooplankton Entrainment
Survival at the Anclote
Power Plant Near Tarpon
Springs, Florida
Fish Deterrent Field Trials
at Hinkley Point Power
Station, Somerset, 1993-
1994
Potrero Power Plant
CWIS316(b)
Demonstration
Evaluation of a Barrier
Net Used to Mitigate Fish
Impingement at a Hudson
River Power Plant Intake
Lovett Generating Station
Gunderboom System
Evaluation Program
Lovett Generating Station
Gunderboom Deployment
Program
Evaluation of the Eicher
Screen at Elwha Dam:
Spring 1990 Test Results
Recent Developments in
Techniques to Protect
Aquatic Organisms at the
Water Intakes of Steam-
Electric Power Plants
Authors
CCI Environmental
Services
AWH Turnpenny, R
Wood, and KP
Thatcher
Ecoogical Analysts
Inc.
JB Hutchinson and
JA Matousek
Lawler, matusky, &
Skelly Engineers
LLP
Lawler, Matusky, &
Skelly Engineers
LLP
Stone and Webster
Engineering
Corporation
Roberto Pagano
and Wade H.B.
Smith - Mitre
Corporation
DCN
DCN 5-4053
DCN 5-431 3
DCN 5-441 4
DCN 5-4391
DCN 5-441 7
DCN 5-4322
DCN 5-4388
DCN 5-4394
Date
1994
1995
1980
1988
1998
2000
1991
1977
Data
Classification
Entrainment
Impingement
Entrainment
Impingement
Impingement
Entrainment
Entrainment
Diversion (not
impinged or
entrained)
Impingement
Facility Name
Anclote Power
Plant
Hinkley Point
Power Station
Potrero Power
Plant
Moss Landing
Bowline Point
Generating Station
Lovett Generating
Station
Lovett Generating
Station
Elwha Dam
Barney Davis
Power Station
Surry Power
Station
Water Body
Type
Estuary
Estuary
Other
Other
Estuary
River/
Freshwater
River/
Freshwater
River/
Freshwater
Estuary
River/Fresh-
Salt-Mixed
Technology
Category
Reduced Intake
Flows - Other
Behavioral
Systems II
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Barriers
Barriers
Barriers
Fixed Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Study
ID
58
59
98
99
100
101
102
103
104
105
106
189
107
108
109
110
4
7
121
122
123
125
126
127
21
18
Test Conditions9
At condenser unit
At discharge
Sound on
Sound off
At intake (control)
At discharge
3-hour intermittent
screen operational
mode
1-hour intermittent
screen operational
mode
Continuous operation
Predeployment
(control)
Postdeployment
Outside test area
(control)
Inside test area
Outside test area
(control)
Inside test area
Controlled Study
Controlled Study
Controlled Study
Controlled Study
Controlled Study
Controlled Study
Controlled Study
Controlled Study
to
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
TO
Q.
70
C7
C7
-------
ba
Exhibit 11B-3. (Continued)
Doc.
ID
43
44
46
47
49
51
52
Document Title
Recent Developments in
Techniques to Protect
Aquatic Organisms at the
Water Intakes of Steam-
Electric Power Plants
Post-Impingement Fish
Survival at Dunkirk Steam
Station
Intake Technologies:
Research Status
Evaluation of the Modular
Inclined Screen at the
Green Island
Hydroelectric Project:
1995 Test Results
Studies of Cooling Water
Intake Structure Effects at
Potomac Electric Power
Company Generating
Stations
Post-Impingement Fish
Survival at Huntley Steam
Station (Winter and Fall)
Fine Mesh Screen (FMS)
Optimization Study
Authors
Roberto Pagano
and Wade H.B.
Smith - Mitre
Corporation
Beak Consultants
Incorporated
Lawler, Matusky &
Skelly Engineers
Stone and Webster
Environmental
Technology and
Services
David E. Bailey,
Jules J. Loos, Elgin
S. Perry
Beak Consultants,
Inc.
Mote Marine
Laboratory
DCN
DCN 5-4394
DCN 5-4327
DCN 4-
4002V-R12
DCN 10-5435
DCN 5-4396
DCN 5-4325
DCN 5-4371
Date
1977
2000
1989
1996
undate
d
1996
1987
Data
Classification
Impingement
Impingement
Impingement
Entrainment
Entrainment
Impingement
Impingement
Entrainment
Facility Name
Barney Davis
Power Station
Surry Power
Station
Dunkirk Steam
Station
Brayton Point
Generating Station
Unit 4
Calvert Cliffs
Nuclear
Generating
Station
Dunkirk Steam
Station
Indian Point
Generating Station
Green Island
Hydroelectric
Project
Chalk Point
Generating Station
Dickerson
Morgantown
Potomac River
Chalk Point
Generating Station
Huntley Steam
Station
Big Bend Power
Station
Water Body
Type
Estuary
River/Fresh-
Salt-Mixed
Great Lakes
Estuary
Estuary
Great Lakes
River/
Freshwater
River/
Freshwater
Estuary
River/
Freshwater
Estuary
River/
Freshwater
Estuary
River/
Freshwater
Ocean
Technology
Category
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Behavioral
Systems I
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Fixed Screen -
Fine Mesh
Barriers
Fixed Screen -
Coarse Mesh
Fixed Screen -
Coarse Mesh
Fixed Screen -
Coarse Mesh
Barriers
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Study
ID
21
18
8
119
83
78
118
79
82
2
14
10
13
12
15
120
1
191
Test Conditions3
Estimated Diversion
Bypass
Angled Screens
Dual Flow Screens
Through Flow
Screens
Dual Flow Screens
Ristroph screens
Predeployment
(control)
Postdeployment
TO
3
Q_
x"
OD
cm
CO
C?
g
5
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
to
Doc.
ID
53
54
60
61
62
64
65
66
Document Title
Chapter 1 0: San Onofre
Units 2 and 3 31 6(b)
Demonstration, The
Effectiveness of the Fish
Return System
Arthur Kill Generating
Station Diagnostic Study
and Post-Impingement
Viability Substudy Report
Third National Workshop
on Entrainment and
Impingement —
Impingement Studies at
Quad-Cities Station,
Mississippi River
Memorandum Report on
the Peripheral Canal Fish
Return Facilities
Third National Workshop
on Entrainment and
Impingement —
Impingement Studies at
Oyster Creek Generating
Station, Forked River,
New Jersey, from Sept. to
Dec. 1975
Fish Survival on Fine
Mesh Travelling Screens
Lecture Notes on Coastal
and Estuarine Studies -
Ecological Studies in the
Middle Reach of the
Chesapeake Bay -
Impingement Studies
Investigations of
Impingement of Aquatic
Organisms at the Calvert
Cliffs Nnuclear Power
Plant, 1975-1995.
Authors
John S. Stevens,
Jr., and Milton S.
Love
Consolidated
Edison Company of
New York
Latvaitiset al.
Edited by Loren
Jensen
Department of Fish
and Game and the
Department of
Water Resources
Thomas & Miller.
Edited by Loren
Jensen
James B. McLaren
Richard Horwitz
T.G. Ringger
DCN
DCN 5-4378
DCN 5-4326
DCN 10-5448
DCN 5-4343
DCN 10-5448
DCN 5-4334
DCN 10-5453
DCN 6-2074
Date
undate
d
2000
1976
1971
1976
2000
1987
1999
Data
Classification
Diversion (not
impinged or
entrained)
Impingement
Impingement
Other
Impingement
Entrapment
Impingement
Impingement
Impingement
Facility Name
San Onofre
Nuclear
Generating Station
(SONGS)
Arthur Kill
Generating Station
Quad Cities
Generating Station
California Delta
Pumping Plant
Oyster Creek
Nuclear
Generating Station
Somerset
Generating Station
Somerset
Generating Station
Calvert Cliffs
Nuclear
Generating Station
Calvert Cliffs
Nuclear
Generating Station
Water Body
Type
Ocean
Estuary
River/
Freshwater
River/
Freshwater
Estuary
Great Lakes
Great Lakes
Estuary
Estuary
Technology
Category
Behavioral
Systems I
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Other technologies
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Study
ID
65
156
157
9
128
11
23
24
19
144
5
50
71
Test Conditions3
Modified Screen No.
24
Modified Screen No.
31
Control
Decompression Test
Control
Pressure Gradient
Test
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
ba
Doc.
ID
71
73
76
78
81
82
Document Title
Impingement Losses at
the DC Cook Nuclear
Power Plant During 1975-
1982 With a Discussion of
Factors Responsible and
Possible Impact on Local
Populations
Fish Return at Cooling
Water Intakes
Bubble Curtain Fish
Exclusion Trials at
Heyshaam 2 Power
Station
An Assessment of the
Effect of the Sizewell
Power Stations on Fish
Populations
Recent Evaluations of
Physical and Behavioral
Barriers for Reducing Fish
Entrainment at
Hydroelectric Plants in the
Upper Midwest
Six Years of Monitoring
the Effectiveness of a
Barrier Net at the
Ludington Pumped
Storage Plants on Lake
Michigan (Waterpower
95)
Authors
N.J. Thurberand
D.J Jude, Great
Lakes and Marine
Waters Center,
University of
Michigan
A.W.H. Turnpenny
A.W.H. Turnpenny
A.W.H. Turnpenny,
C.J.L Taylor
D.T. Michaud, E.P.
Taft
E.R. Guilfoos, R.W.
Williams, T.E.
Rourke, P.B.
Latvaitis, J.A.
Gulvas, R.H.
Reider
DCN
DCN 5-4374
DCN 5-4301
DCN 5-4303
DCN 5-4300
DCN 10-5465
DCN 10-5466
Date
1985
1992
1993
2000
1999
1995
Data
Classification
Impingement
Impingement
Impingement
Impingement
Entrainment
Percent
effectiveness
Facility Name
DC Cook
Le Blayais
Heysham Power
Station
Sizewell A and B
Various Coastal
Stations in the
U.K.
Pine Hydroelectric
Project
Luddington
Pumped Storage
Water Body
Type
Great Lakes
Ocean
Ocean
Ocean
River/
Freshwater
Great Lakes
Technology
Category
Off-shore Location
(any combination
other than velocity
cap)
Traveling Screen -
Fine Mesh
Behavioral
Systems II
Off-shore Location
with velocity Cap
Off-shore Location
with velocity Cap
Behavioral
Systems II
Barriers
Study
ID
55
6
40
41
42
45
46
17
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
145
Test Conditions3
Bubbles off
Bubbles on
1981 -82 study
1992 study
Strobes On
Sound on
Strobe/sound
Control
Strobes On
Sound on
Strobe/sound
Control
Strobes On
Sound on
Strobe/sound
Control
Strobe/air
Sound/air
Air
Control
TO
3
Q_
x"
OD
cm
CO
C?
g
5
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
to
Doc.
ID
84
85
103
106
108
115
Document Title
Evaluation of the
Effectiveness of Intake
Wedgewire Screens
Circulating water traveling
screen modifications to
improve impinged fish
survival and debris
handling at Salem
Generating Station
Evaluation of 31 6(b)
Demonstration: Detroit
Edison's Monroe Power
Plant
Biological and
Engineering Evaluation of
a Fine-Mesh Screen
Intake for Big Bend
Station Unit 4
1991 Annual Report
Describing Performance
of Deterrent Net System
at JR Whiting
The Effects of Screen Slot
Size, Screen Diameter,
and Through-Slot Velocity
on Entrainment of
Estuarine Ichthyoplankton
through Wedgewire
Screens
Authors
C. Ehrler, C.
Raifsnider
John P. Ronafalvy,
R. Roy Cheesman,
William M. Matejek
CD Goodyear,
Great Lakes
Fishery Laboratory
Stone & Webster
Engineering
Consumers Power
Company
Stephen B.
Weisburg, William
H. Burton, Eric A.
Ross, Fred Jacobs
DCN
DCN 5-4335
DCN 5-4333
DCN 5-4360
DCN 6-5037
DCN 5-4409
DCN 5-4008
Date
2000
2000
1978
1980
1992
1984
Data
Classification
Entrainment
Impingement
Impingement
Impingement
Impingement
Entrainment
Facility Name
Logan Generating
Plant
Salem Generating
Station
Monroe Power
Plant
Big Bend Power
Station
JR Whiting
Test barge (Chalk
Point)
Water Body
Type
River/
Freshwater
Estuary
Great Lakes
Estuary
Great Lakes
Estuary
Technology
Category
Fixed Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Barriers
Fixed Screen -
Fine Mesh
Study
ID
240
146
147
188
16
148
149
206
207
208
209
210
241
242
243
Test Conditions3
Original Screen
Modified Screen
Control
Test
8/82 study, 1 mm slot
width
8/82 study, 2mm slot
width
7/83 study, 1 mm slot
width, 0.20 m/s slot
velocity
7/83 study, 2mm slot
width, 0.20 m/s slot
velocity
7/83 study, 3mm slot
width, 0.20 m/s slot
velocity
7/83 study, 2mm slot
width, 0.095 m/s slot
velocity
7/83 study, 2mm slot
width, 0.1 9 m/s slot
velocity
7/83 study, 2mm slot
width, 0.40 m/s slot
velocity
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
ba
Doc.
ID
118
125
126
130
Document Title
Biological Evaluation of a
Fine-Mesh Traveling
Screen for Protecting
Organisms
Review of Portions of
NJPDES Renewal
Application for the
PSE&G salem Generating
Station
Effectiveness, Operation
and Maintenance, and
Costs of a Barrier Net
System for Impingement
Reduction at the Chalk
Point Generating Station
The Impact of
Entrainment and
Impingement on Fish
Populations in the Hudson
River Estuary for Six Fish
Populations Inhabiting the
Hudson River Estuary
Authors
Edward taft,
Thomas Horst, and
Stone and Webster
Engineering
Corporation
NJ DEP; Prepared
by ESSA
Technologies
David Baily, Jules
Loos, Ann
Wearmouth, Pat
Langley, Elgin
Perry
J. Boreman, L.W.
Barnthouse, D.S.
Vaughan, C.P.
Goodyear, S.W.
Christensen, K.D.
Kumar, B.L. Kirk,
W. Van Winkle
DCN
DCN 10-5492
DCN 4-1 51 6
DCN 6-5046E
DCN 5-4361
Date
1981
2000
1982
Data
Classification
Impingement
Impingement
Impingement
Entrainment
Facility Name
Big Bend Power
Station
Salem Generating
Station
Chalk Point
Generating Station
Bowline Point
Generating Station
Danskammer
Point Generating
Station
Indian Point
Generating Station
Lovett Generating
Station
Multiple test
facilities
Roseton
Generating Station
Water Body
Type
Ocean
Estuary
Estuary
River/
Freshwater
River/
Freshwater
River/
Freshwater
River/
Freshwater
River/
Freshwater
River/
Freshwater
Technology
Category
Traveling Screen -
Fine Mesh
Behavioral
Systems II
Barriers
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Study
ID
74
75
76
77
84
85
86
87
60
61
113
114
218
224
221
227
217
220
223
226
219
225
62
63
216
222
Test Conditions3
Test
Control
Test
Control
Test
Control
Test
Control
Sound on
Sound off
1976-77 estimates
1984-85 estimates
GBC estimation
method
MU method
GBC estimation
method
MU method
GBC estimation
method -Unit 2
GBC estimation
method - Unit 1
MU method - Unit 2
MU method - Unit 1
GBC estimation
method
MU method
Historical estimates -
GBC or RDM
methods
Historical estimates -
MU method
GBC estimation
method
TO
3
Q_
x"
OD
cm
CO
C?
g
5
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
Doc.
ID
136
138
141
143
146
147
151
152
Document Title
Intake Debris Screen
Postimpingement Survival
Evaluation Study:
Roseton Generating
Station 1990
Fish Return System
Efficacy and Impingement
Monitoring Studies for
JEA's Northside
Generating System
A Study of Fish
Impingement and Screen
Passage at Hanford
Generation Project - A
Progress Report
Final Report: Biological
Evaluation of a Modified
Traveling Screen Mystic
^tatinn I Init Mn 7
Design of Water Intake
Structures for Fish
Protection
1974 Evaluation of the
Glenn-Colusa Irrigation
District Fish Screen
Design and Testing
Specification for a
Deterrent Bubble Barrier
for Heysham Power
Stations 1 & 2
Experiments on the Use
of Sound as a Fish
Deterrent
Authors
Lawler, Matusky &
Skelly Engineers
Isabel C. Johnson
and Steve Moser
R. H. Gray, T. L.
Page, E. G. Wolf,
M. J. Schneider
(Batelle)
Stone & Webster
Engineering
Corporation
American Society
of Civil Engineers
Ronald J. Decoto
AWH Turnpenny,
PA Henderson
AWH Turnpenny,
K P Thatcher, R
Wood, P H
Loeffelman
DCN
DCN5-4317
DCN 6-5046H
DCN 5-4363
DCN 5-4369
DCN 6-5057
DCN 5-4308
DCN 5-431 5
DCN 5-431 6
Date
1991
0
1975
1981
1982
1974
1992
1993
Data
Classification
Impingement
Impingement
Impingement
Impingement
Impingement
Diversion (not
impinged or
entrained)
Diversion (not
impinged or
entrained)
Diversion (not
impinged or
entrained)
Facility Name
Roseton
Generating Station
JEA Northside
Generating
System
Roseton
Generating Station
Hanford
Generating Project
Mystic Generating
Station
No facility
specified
Glenn-Colusa
Irrigation District
Fish Screen
Heysham Power
Station
Fawley Aquatic
Research
Laboratory
Water Body
Type
Estuary
Estuary
Estuary
River/
Freshwater
River/Fresh-
Salt-Mixed
River/
Freshwater
Ocean
Ocean
Technology
Category
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Other technologies
Other technologies
Behavioral
Systems II
Behavioral
Systems II
Study
ID
68
70
72
129
186
187
47
48
51
49
43
44
88
89
90
73
64
52
53
54
56
57
Test Conditions3
Dual Flow Screens
Dual Flow Screens
Conventional
Traveling Screens
Conventional
Traveling Screens
Fish impingement
Invertebrate
Continuous operation
1.5 hours off, 0.5
hours on
Continuous operation
1.5 hours off, 0.5
hours on
% in. screen
1/8 in. screen
Low Velocity Screen
Speed
Medium Velocity
Screen Speed
High Velocity Screen
Speed
Air
Strobes On
Strobe/air
Sound off
Sound on
to
^
OS
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
ba
Doc.
ID
163
164
167
168
169
Document Title
Impingement Survival
Studies on White Perch,
Striped Bass, and Atlantic
Tomcod at Three Hudson
River Power Plants
Survival of Fishes and
Macroinvertibrates
Impinged at Oyster Creek
Generating Station
A Practical Intake Screen
which Substantially
Reduces the Entrainment
and Impingement of Early
Life Stages of Fish
Survival of Dominant
Estuarine Organisms
Impinged on Fine-Mesh
Traveling Screens at the
Barney M. Davis Power
Station
Investigations on the
Protection of Fish Larvae
at Water Intakes Using
Fine-Mesh Screening
Authors
Lawrence R. King,
Jay B. Hutchison
Jr., Thomas G.
Huggins
Thomas R.
Thathom, David L.
Thomas, Gerald J.
Miller
Brian N. Hanson,
Wiliam H. Bason,
Barry E. Beitz,
Kevin E. Charles
L.S. Murray and
T.S. Jinnette
D.A. Tomljanovich,
J.H. Heuer, and
C.W. Voigtlander
DCN
DCN 10-5332
DCN 10-5333
DCN 10-5536
DCN 5-4379
DCN 5-4379
Date
1977
1977
0
1977
1978
Data
Classification
Impingement
Impingement
Entrainment
Impingement
Impingement
Retention
Facility Name
Bowline Point
Generating Station
Roseton
Generating Station
Oyster Creek
Nuclear
Generating Station
Delmarva
Ecological
Laboratory
Barney Davis
Power Station
TVA laboratory
TVA laboratory
Water Body
Type
Estuary
River/Fresh-
Salt-Mixed
Estuary
Not Applicable
Estuary
Not Applicable
Technology
Category
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Fixed Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Fine Mesh
Study
ID
153
154
150
253
66
151
248
249
250
251
252
Test Conditions3
0.5 mm mesh
1.0mm mesh
1.3 mm mesh
1.8mm mesh
2.5mm mesh
TO
3
Q_
x"
OD
cm
CO
C?
g
5
•g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
Doc.
ID
170
171
Document Title
A Study on the Protection
of Fish Larvae at Water
Intakes Using Wedge-
Wire Screens
Practicality of Profile-Wire
Screen in Reducing
Entrainment and
Impingement
Authors
J.H. Heuer and
D.A. Tomljanovich
B.N. hanson, W.H.
Bason, B.E. Beitz,
and K.E. Charles
DCN
DON 5-4379
DCN 5-4379
Date
1987
1977
Data
Classification
Diversion (not
impinged or
entrained)
Impingement
Facility Name
TVA laboratory
Test laboratory
Water Body
Type
Not Applicable
Technology
Category
Fixed Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Study
ID
92
93
94
95
96
97
132
133
134
135
136
137
138
139
140
141
142
143
152
Test Conditions3
Horizontal Screen -
0.5mm slot
Horizontal Screen -
1.0 mm slot
Horizontal Screen -
2.0mm slot
Vertical Screen -
0.5mm slot
Vertical Screen -
1.0mm slot
Vertical Screen -
2.0mm slot
Horizontal Screen -
0.5mm slot
Horizontal Screen -
0.5mm slot
Horizontal Screen -
1.0mm slot
Horizontal Screen -
1.0 mm slot
Horizontal Screen -
2.0mm slot
Horizontal Screen -
2.0mm slot
Vertical Screen -
0.5mm slot
Vertical Screen -
0.5mm slot
Vertical Screen -
1.0mm slot
Vertical Screen -
1.0mm slot
Vertical Screen -
2.0mm slot
Vertical Screen -
2.0mm slot
Test
to
^
00
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
ba
Doc.
ID
175
180
184
187
191
192
193
Document Title
Seminole Plant Units 1&2
31 6b Study Report
316(a)and316(b)
Demonstration
Cumberland Steam Plant
Brunswick Steam Electric
Plant Cape Fear Studies
Interpretive Report
Vienna Power Station
Perdiction of Aquatic
Impacts of the Proposed
Cooling Water Intake A
Section 31 6(b)
Demonstration
Field evaluation of
wedgewire screens for
protecting early life stages
at cooling water intake
structures: Chesapeake
Bay studies
Laboratory evaluation of
modified Ristroph
traveling screens for
protecting fish at cooling
water intakes
Fish Protection at Cooling
Water Intake Structures:
A Technical Reference
Manual
Authors
Dames and Moore
Tennessee Valley
Authority
Carolina Power &
Light Company
Delmarva Power &
Light Company
EPRI
EPRI
EPRI
DCN
DCN 7-4530
DCN 10-5547
DCN 8-451 3
DCN 10-5554
DCN 10-6806
DCN 10-6801
DCN 10-6813
Date
2006
2006
2007
Data
Classification
Entrainment
Entrainment
Entrainment
Entrainment
Entrainment
Impingement
Entrainment
Facility Name
Test barge (St.
John's River)
Cumberland
Steam Plant
Brunswick Steam
Electric Plant
Vienna Power
Station
Test barge
(Chesapeake Bay)
Test laboratory
Test barge (Oyster
Creek)
Test barge
(Portage River)
Water Body
Type
Estuary
Estuary
River/
Freshwater
Not Applicable
Estuary
River/
Freshwater
Technology
Category
Fixed Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Study
ID
213
214
215
244
245
247
200
201
202
203
112
130
131
211
212
196
197
198
199
193
194
Test Conditions3
1 mm mesh
2 mm mesh
Screen type #1
Screen type #2
0.5mm mesh, 0.15
m/sslot vel.
0.5mm mesh, 0.3
m/s slot velocity
1.0 mm mesh, 0.15
m/sslot vel.
1.0 mm mesh, 0.3
m/s slot velocity
1 ft/s velocity
2 ft/s velocity
3 ft/s velocity
1 mm mesh
2mm mesh
0.5mm mesh, 0.15
m/sslot vel.
0.5mm mesh, 0.3
m/s slot velocity
1.0 mm mesh, 0.15
m/s slot vel.
1.0mm mesh, 0.3
m/s slot velocity
0.5mm mesh, 0.3
m/s slot velocity
1.0 mm mesh, 0.15
m/sslot vel.
TO
3
Q_
x"
OD
cm
CO
C?
g
5
-g
(A
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
to
Doc.
ID
193
Document Title
Fish Protection at Cooling
Water Intake Structures:
A Technical Reference
Manual
Authors
EPRI
DCN
DON 10-6813
Date
2007
Data
Classification
Impingement
Facility Name
Test barge
(Sakkonet River)
Tracy Fish
Collecting Facility
Arthur Kill
Generating Station
Bowline Point
Generating Station
Brayton Point
Generating Station
Unit 4
Brunswick Steam
Electric Plant
Danskammer
Point Generating
Station
Dunkirk Steam
Station
Indian Point
Generating Station
Mystic Generating
Station
Water Body
Type
River/
Freshwater
River/
Freshwater
River/
Freshwater
Estuary
Estuary
Estuary
Estuary
Great Lakes
River/
Freshwater
River/
Freshwater
Technology
Category
Fixed Screen -
Fine Mesh
Other technologies
Fixed Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Study
ID
192
193
194
195
182
183
155
176
177
178
180
181
165
166
168
169
159
163
190
172
173
174
175
Test Conditions3
0.5 mm mesh, 0.15
m/s slot vel.
0.5mm mesh, 0.3
m/s slot velocity
1.0mm mesh, 0.15
m/s slot vel.
1.0mm mesh, 0.3
m/s slot velocity
Technology in Place
Control
Original Screen
Screenwash -
Continuous
Screenwash - 2hr
hold
Screenwash - 4hr
hold
Initial survival
Extended survival
Technology in Place
Technology in Place
Screenwash -
Continuous
Screenwash - 2hr
hold
Dual Flow Screens
Ristroph Screen
Original Screen
Screenwash -
Continuous
Screenwash - 2hr
hold
Screenwash - 4hr
hold
Screenwash - 8hr
hold
TO
3
Q_
x"
OD
cm
U)
IQ
~n
o
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
to
Doc.
ID
193
195
196
205
206
207
Document Title
Fish Protection at Cooling
Water Intake Structures:
A Technical Reference
Manual
Laboratory evaluation of
fine-mesh traveling water
screens for protecting
early life stages offish at
cooling water intakes
Latent impingement
mortality assessment of
the Geiger Multi-Disc
screening system at
Potomac River
Generating Station
Calvert Cliffs Nuclear
Power Plant Finfish
Survival Study
Full-scale Operational
Demonstration of Fine
Mesh Screens at Power
Plant Intakes
Dunkirk Station Biological
Studies
Authors
EPRI
EPRI
EPRI
D.L.Breitburg and
T.A.Thoman
V. Brueggemeyer,
D.Cowdrick, K.
Durrell, S.
Mahadevan and D.
Bruzek
Beak Consultants
Incorporated
DCN
DCN 10-
6813
DCN 10-6802
DCN 10-6814
DCN 10-5571
DCN 10-5572
DCN 10-5573
Date
2007
2008
2007
1986
1998
1988
Data
Classification
Impingement
Impingement
Retention
Impingement
Impingement
Impingement
Impingement
Facility Name
Oswego Steam
Station
Oyster Creek
Nuclear
Generating Station
Prairie Island
Nuclear
Generating Station
Salem Generating
Station
Sioux
Test laboratory
Test laboratory
Potomac River
Calvert Cliffs
Nuclear
Generating
Station
Big Bend Power
Station
Dunkirk Steam
Station
Water Body
Type
Great Lakes
Estuary
River/
Freshwater
Estuary
Not Applicable
Not Applicable
River/
Freshwater
Estuary
Estuary
Great Lakes
Technology
Category
Off-shore Location
(any combination
other than velocity
cap)
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Other technologies
Fixed Screen -
Fine Mesh
Fixed Screen -
Fine Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Traveling Screen -
Fine Mesh
Study
ID
158
179
160
161
162
185
117
116
91
236
237
238
239
233
234
235
228
229
Test Conditions3
Modified Screen
Original Screen
Beauderey TS
FMC dual-speed TS
FMC single-speed
TS
FMC single-speed
TS
Screenwash
Org. Return
Discharge
At intake (control)
High Velocity Screen
Speed
Low Velocity Screen
Speed
TO
3
Q_
x"
OD
cm
CO
C?
g
5
TO
Q.
70
C7
C7
-------
Exhibit 11B-3. (Continued)
to
Doc.
ID
208
Document Title
Brunswick Steam Electric
Plant: 1984 Biological
Monitoring Report
Authors
Carolina Power and
Light Company
DCN
DCN 10-5574
Date
1984
Data
Classification
Impingement
Facility Name
Brunswick Steam
Electric Plant
Water Body
Type
Estuary
Technology
Category
Traveling Screen -
Fine Mesh
Study
ID
167
230
231
232
Test Conditions3
Control
High Velocity Screen
Speed
Low Velocity Screen
Speed
Juvenile/adults
TO
3
Q_
x"
OD
' Specified primarily to distinguish between different rows for the same facility, technology, and data type.
cm
U)
IQ
~n
o
•g
(A
TO
Q.
70
C7
C7
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
In general, a row of the data table contains quantitative performance measures presented
for a given species (possibly of a certain age) at a given point in time, taken from either a
table of the document or within text. Records between the two database tables were
linked by study ID.
For a given document, the performance study database contains selected data that
represented one of the above data types and met acceptance criteria for the summaries
and analyses. If there was any uncertainty in how to interpret the data in a given
document, then that data were not entered into the database until the data could be further
reviewed. In addition, a given performance measure could be defined differently in
different documents. For example, as stored in the database, data on percent survival
could represent actual survival following impingement in one document, and percent
diversion from impingement or entrainment in another document. Survival counts may
include injured fish in one document and not in another.
11B.2.6 Classifying data (e.g., impingement, entrainment)
From available information in a document, reviewers determined whether a particular set
of performance data related to either impingement or entrainment of fish. This
classification was done primarily by noting how the document classified the data as
impingement or entrainment, typically within text or in titles to tables or sections of the
document. Occasionally, it was not possible to determine an exact classification of data.
For example, data may have represented a percent offish that were diverted from the
areas close to the cooling water intakes of a facility, where no information was provided
on the age or size categories of the fish. In this case, it was undetermined whether the
diverted fish would have been impinged or entrained. Because they could represent
either situation, such data are categorized in the performance study database as diverted,
but neither impinged nor entrained. They were placed in a category separate from
impingement and entrainment data when conducting data summaries and analyses.
11B.3 Statistical Data Summaries
When considering all of the performance data that were entered into the performance
study database, two types of data were primarily encountered:
• Data that originate from simple observational studies (i.e., studies that provide
impingement/entrainment data at one or more points in time, when the given
technology is in operation).
• Paired data sets that correspond to either "before/after implementation" of the
technology or "treatment/control," which allow for comparisons to be made to
some baseline condition when evaluating technology performance at a given
location.
The first type of data was primarily percentage in nature. When expressed in relative
(percentage) terms rather than in absolute terms, data are more likely to be comparable
across different studies and different testing situations. Of these data, percent mortality
and/or survival were reported most often in the documents. Prior to the statistical
HB-23
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Chapter 11: Appendix B § 316(b) Existing Facilities Proposed Rule -TDD
summaries and analyses, percent survival data were converted to percent mortality data
(by subtracting the percentage from 100 percent) so that survival-related data among the
studies could be reported as percent mortality. Note, however, that when percent survival
data represented a percentage of a positive outcome, such as successful diversion, then
percent mortality would represent the percentage of the opposite outcome. Data that
correspond to the numerator and/or denominator of such a percentage (i.e., fish counts or
biomass) were also entered in the database when they were reported within the
documents.
The second type of data represents situations where a document reported either counts or
percentages of organisms as measured under a baseline condition as well as conditions
when the technology was in place (i.e., "treatment" conditions). Ideally, baseline
conditions should match treatment conditions except for the technology not being in
operation. A document was more likely to have these two types of data when reporting
the results of controlled laboratory studies. When a document reported both treatment
and control data for a given technology, both sets of data were entered into the
performance study database (under different study IDs but the same document ID). For
the statistical summaries, these results were expressed as a percentage change from
baseline or control:
Baseline - Treatment ., ^_.
* 100%
Baseline
Here, "Baseline'" and "Treatment" can represent any of the percentage or count measures
noted in Section 1 IB.2, but both must represent the same type of measure within a given
calculation.
This section presents simple statistical summaries of performance measurements stored
within the performance study database, with separate summaries presented for the two
data classifications. These data originate from the documents listed in Exhibit 11B-3.
Separate summaries were also prepared for data classified as impingement, entrainment,
or other, and for data associated with different technology categories. In addition, for
percent mortality data, summaries are presented according to the observation time (e.g.,
number of hours following impingement or entrainment when the mortality or survival of
fish was noted).
The statistical summaries presented in this section include the number of measurements
(N), arithmetic mean, standard deviation, minimum, maximum, and selected percentiles
(25 , 50*, 75*, and 95 percentiles). These summaries represent measurements that span
different documents, studies, implementations of the technology, test conditions, species,
age categories, time periods/seasons, etc. Thus, the variability observed among these
data contains many different components. However, the number of different studies,
documents, and test conditions entering into each set of summary statistics will vary
among the different technology categories and data classifications. Because data for a
particular type of performance measure were generated under different conditions and
could have slightly different interpretations and definitions from study to study, it is not
feasible to assume that all data in a combined dataset originate from a common
underlying distribution. Therefore, the summaries presented in this section do not
HB-24
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
assume an underlying distribution to the data, such as normality, but rather, are calculated
using only the observed data.
11 B.3.1 Summaries of Observational Data Expressed as Percentages
Exhibits 11B-4 through 11B-6 contain descriptive statistics for data on percent mortality,
percent biomass, and percent injury, respectively. The nearly 2,000 data values
summarized in these tables represent only those conditions in which the specified
technology was deemed to be in operation (e.g., any data labeled as collected under
control conditions were excluded). To help determine how data entering into these tables
may be distributed among different documents and test conditions within documents,
Section 1 IB.5 contains the mean, minimum, and maximum data value for each
combination of document and study (test condition), for each technology category. The
tables in Section 1 IB.5 also list the facilities from which the data originate.
Some findings noted from the summaries of the percent mortality data presented in
Exhibit 11B-4 are as follows:
• Across species, time points, and studies, percent mortality data were observed to
cover the range of 0 to 100 percent among the technology categories, especially
for impingement.
• Approximately two-thirds of the percent mortality data, obtained from 33
documents, are associated with impingement.
o For traveling screens, the ranges of percent impingement mortality data are
similar between coarse and fine mesh.
• Mean percent mortality associated with traveling screens (coarse mesh)
range from 16 to 53 percent across the different duration times following
impingement. The data originate from 46 different test conditions within
18 documents.
• For traveling screens (fine mesh), mean percent mortality ranges from 18
to 37 percent across duration times, but all time points have percent
mortality data that covers a range from 0 to 100 percent. They represent
31 test conditions across 12 documents.
o The five remaining technology categories with percent mortality data for
impingement had data that originated from eight documents. Of these
technologies, barriers had the highest range of percent mortality values, with a
median of 91.9 percent. Data on off-shore location technology also covered a
high range overall, but only eight data points were present.
• When mortality data were available at different elapsed times following
impingement, an increase in mortality was occasionally seen with higher elapsed
times. However, a clear increasing trend in time is not observed due to
considering different studies and test conditions.
HB-25
-------
Chapter 11: Appendix B
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11B-4. Descriptive Statistics
Technology Category and Mortality
on Percent Mortality Performance Data, by
Observation Time
Technology Category
Mortality
Obs.
Time
N
Mean
Std.
Dev.
Min.
Max.
Percent! les
25th
50th
75th
95th
Entrainment
Fixed Screen - Fine
Mesh
Other technologies
Reduced Intake Flows
- Other
Traveling Screen -
Coarse Mesh
Ohr.
24 hr.
48 hr.
Ohr.
Ohr.
Ohr.
24 hr.
96 hr.
13
12
12
11
177
115
133
1
18.7
41.5
53.3
1.0
27.9
4.1
6.3
92.2
31.7
41.7
43.6
0.6
23.3
9.7
11.4
0.0
0.0
0.0
0.0
0.0
0.1
0.1
92.2
100.0
100.0
100.0
1.9
88.4
83.9
77.8
92.2
0.0
0.0
5.0
0.4
7.4
0.5
0.7
92.2
0.0
33.8
56.3
1.1
24.9
1.3
2.0
92.2
24.1
82.4
100.0
1.4
42.6
3.3
5.7
92.2
100.0
100.0
100.0
1.9
76.0
20.3
25.4
92.2
Impingement
Barriers
Behavioral Systems 1
Fixed Screen - Fine
Mesh
Off-shore Location
(any combination othe
Other technologies
Traveling Screen -
Coarse Mesh
Traveling Screen -
Fine Mesh
Ohr.
Ohr.
Ohr.
12hr.
24 hr.
48 hr.
Ohr.
Ohr.
Ohr.
18hr.
24 hr.
48 hr.
84 hr.
96 hr.
Ohr.
8hr.
24 hr.
48 hr.
96 hr.
21
12
38
10
40
10
8
6
684
26
233
34
18
91
373
67
67
82
70
71.1
39.8
23.7
27.2
43.0
30.7
48.3
7.5
26.4
31.7
16.0
23.9
15.5
52.7
25.5
22.4
28.6
17.7
37.4
35.7
40.1
27.6
32.3
38.3
33.3
23.6
11.4
33.4
25.4
28.5
37.0
25.1
38.3
32.9
32.5
34.9
30.2
35.8
1.3
1.2
0.0
0.0
0.0
1.0
8.0
0.0
0.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
98.7
100.0
91.8
91.0
100.0
91.0
85.2
30.0
100.0
82.0
100.0
100.0
80.2
100.0
100.0
100.0
100.0
100.0
100.0
54.9
7.0
0.8
3.0
4.0
3.0
37.5
0.0
0.0
12.0
0.0
0.0
0.0
16.7
0.0
0.0
0.0
1.0
5.1
91.9
23.3
10.5
16.5
32.2
22.0
46.3
4.0
9.2
26.5
1.4
0.0
4.7
50.0
8.0
4.9
12.6
3.9
26.4
97.7
85.1
44.9
28.0
84.9
31.0
62.9
7.0
45.4
42.0
16.8
45.7
15.8
100.0
43.2
30.3
50.0
15.9
63.6
98.7
100.0
81.1
91.0
100.0
91.0
85.2
30.0
100.0
80.0
100.0
100.0
80.2
100.0
98.5
100.0
100.0
96.8
100.0
Diversion (not impinged or entrained)
Behavioral Systems 1
Behavioral Systems II
Fixed Screen - Coarse
Mesh
Fixed Screen - Fine
Mesh
Other technologies
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
64
5
12
296
2
24.6
81.7
0.5
11.5
74.2
31.4
25.9
0.5
16.0
11.5
0.0
38.2
0.0
0.0
66.0
100.0
100.0
1.4
86.5
82.3
2.4
77.4
0.1
0.6
66.0
9.4
96.2
0.4
5.0
74.2
36.8
96.5
0.9
17.6
82.3
95.5
100.0
1.4
47.0
82.3
Other
Traveling Screen -
Coarse Mesh
24 hr.
48 hr.
16
16
12.0
21.2
18.4
27.2
0.0
0.0
53.5
69.6
0.0
1.9
1.4
4.7
24.6
45.2
53.5
69.6
11B-26
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix B
Exhibit 11B-5. Descriptive Statistics on Percent Biomass Performance Data, by
Technology Category
Technology Category
N
Mean
Std.
Dev.
Min.
Max.
Percent! les
25tn
50tn
75tn
95tn
Entrainment
Barriers
Fixed Screen - Coarse Mesh
5
13
18.9
5.5
31.9
5.8
3.3
0.1
76.0
18.0
4.4
2.0
5.1
3.0
5.8
9.0
76.0
18.0
Impingement
Off-shore Location with velocity Cap
Traveling Screen - Coarse Mesh
7
48
42.1
1.4
64.9
2.6
0.2
0.0
180.0
12.8
1.4
0.1
6.5
0.3
52.0
1.2
180.0
7.6
Exhibit 11B-6. Descriptive Statistics on Percent Injury Performance Data, by
Technology Category
Technology Category
N
Mean
Std.
Dev.
Min.
Max.
Percentiles
25tn
50tn
75tn
95tn
Impingement
Traveling Screen - Coarse Mesh
Traveling Screen - Fine Mesh
20
30
28.1
7.3
15.9
9.9
5.0
0.0
64.0
34.0
12.5
0.4
28.5
2.9
38.5
9.5
57.0
29.8
Diversion (not impinged or entrained)
Fixed Screen - Coarse Mesh
12
8.0
7.8
1.5
22.5
2.3
4.4
13.1
22.5
• Entrainment data represented 17 percent of the percent mortality data and
originated from six different documents.
o Of the four technology categories for which entrainment data existed, fixed
screen (fine mesh) was associated with the lowest range of percent mortality
data (when mortality was noted immediately following entrainment). These
data originated primarily from Green Island Hydroelectric Project (Document
47) and represented primarily blueback and American shad juveniles.
o The traveling screen (coarse mesh) technology was represented by percent
mortality data from two documents, but from several test facilities. Document
18 (Potrero power plant) contributed the two largest values (83.9 and 92.2
percent), while Document 130 (multiple test facilities) provided values
ranging from 0.1 to 77.8 percent.
• Five technology categories were associated with diversion data that could not be
expressed as either impingement or entrainment. These data represented
approximately 14 percent of all percent mortality data and originated from six
documents and six different facilities. Within a technology category, data
originated from either one or two documents. For some categories, such as
Behavioral Systems II, different studies or test conditions appeared to be a major
source of variation in the data.
The "other" category represented data from a single document (Document 61), collected
from a controlled study at the California Delta Pumping Plant. The data represent the
outcome of decompression tests in which fish were subjected to various pressure levels
and evaluated for survival after one and two days. These tests evaluated the ability of
HB-27
-------
Chapter 11: Appendix B § 316(b) Existing Facilities Proposed Rule -TDD
fish to withstand hydrostatic pressures between various points of the facility and the
release point.
Exhibits 11B-5 and 11B-6 note that very little biomass or injury performance data are
represented within the database. Percent biomass data represent approximately four
percent of the performance data expressed as a percentage, while percent injury data
represent about three percent. In a given row of these two tables, the summarized data
originate from only one reviewed document and from one to four studies within that
document. Some findings noted in these two tables are as follows:
• Entrainment data existed as a percent of total biomass for two technology
categories: barriers and fixed screen - coarse mesh. The 18 entrainment data
points represent four different facilities owned by a single utility and originate
from Document 49, which labeled the data points as a percent of total water body
production. While the largest reported measure is 76 percent (measured at a
facility that utilized barriers), which represented entrainment of bay anchovies, it
is considerably higher than the second highest reported measure, 18 percent.
• Impingement data expressed as a percent of total biomass were reported for only
two technology categories. For one category (offshore location with velocity
cap), the data represented different species from various coastal stations in the
United Kingdom in 1990 (Document 78). The summarized percentages for this
category were calculated from total biomass that was reported in this document.
The other category (traveling screens - coarse mesh) represents percentage data
for Quad Cities Generating Station that was reported for Document 60. These
data were considerably lower than for the other technology category.
• Traveling screen performance data were expressed as a percentage of total injured
fish for two documents: Document 164 (coarse mesh) and Document 192 (fine
mesh). The latter document reported on the outcome of controlled testing in a
laboratory under three different velocity measures (1,2, and 3 feet per second).
11B.3.2 Summaries of Observational Data Expressed as
Mortality/Survival Counts
Exhibits 11B-7 and 11B-8 contain descriptive statistics on mortality count data and
survival count data, respectively, which exist within the database. Count data are
reported only when they were provided within a document and were not derived from
percentage data. Section 1 IB.6 contains a finer summary of these data by document,
study (test condition), and facility, for each technology category appearing in Exhibits
11B-7 and 11B-8. Some key findings are as follows:
• Few counts listed in the database on mortality or survival are associated with
entrainment. For a given technology, available entrainment data originate from
one or two documents. Entrainment mortality counts under fine mesh fixed
screens tend to be low (Document 18) compared to barriers (Documents 40
and 41).
HB-28
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix B
• For barriers and Behavioral Systems II, both mortality and survival impingement
counts are quite high (with higher counts associated with barriers) and originate
from different documents.
• When traveling screens (coarse mesh) are in place, mortality counts following
impingement vary considerably (from zero to over two million) under different
test conditions and facilities, especially immediate mortality. However, the
largest mortality counts occur in only a few instances, as noted by low values for
the 75* percentile, and median counts are close to zero. Section 1 IB.6 shows that
the highest mortality counts were associated with facilities at Calvert Cliffs and
Roseton.
• With the exception of survival counts associated with the Brunswick plant,
survival counts associated with impingement were similar between fine and
coarse mesh traveling screens.
Because count data can be interpreted differently between studies and can be highly
affected by test condition, caution should be taken when making conclusions from
summaries of these data.
Exhibit 11B-7. Descriptive Statistics on Mortality Count, by Technology Category and
Mortality Observation Time
Technology Category
Mortality
Obs.
Time
N
Mean
Std.
Dev.
Min.
Max.
Percentiles
25th
50th
75th
95th
Entrainment
Barriers
Fixed Screen - Fine
Mesh
Traveling Screen -
Coarse Mesh
Ohr.
Ohr.
24 hr.
48 hr.
Ohr.
8
13
12
12
1
1368
5
33
40
601
2106
9
59
73
1
0
0
0
601
6133
28
170
208
601
106
0
0
1
601
341
0
7
7
601
1959
10
28
32
601
6133
28
170
208
601
Impingement
Barriers
Behavioral Systems II
Fixed Screen - Fine
Mesh
Off-shore Location (any
combination)
Traveling Screen -
Coarse Mesh
Traveling Screen - Fine
Mesh
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
96 hr.
Ohr.
12
4
1
8
478
130
58
125
396037
10282
129
356
15596
26
26
20850
635609
8144
625
122127
95
114
81984
232
912
129
13
0
0
0
0
1948132
20564
129
1647
2229859
866
848
521500
14739
4577
129
20
0
0
1
4
118945
9826
129
31
3
0
3
31
489462
15987
129
544
50
3
10
753
1948132
20564
129
1647
8985
111
77
113280
Other
Traveling Screen -
Coarse Mesh
24 hr.
48 hr.
28
28
7
14
11
19
0
0
52
82
0
1
1
5
10
25
25
47
11B-29
-------
Chapter 11: Appendix B
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11B-8. Descriptive Statistics on Survival Count, by Technology Category and Mortality
Observation Time
Technology Category
Mortality
Obs.
Time
N
Mean
Std. Dev.
Min.
Max.
Percentiles
25th
50th
75th
95th
Entrainment
Behavioral Systems II
Traveling Screen -
Coarse Mesh
Ohr.
Ohr.
96 hr.
12
1
1
5766
115
56
9396
388
115
56
23572
115
56
477
115
56
765
115
56
9345
115
56
23572
115
56
Impingement
Barriers
Behavioral Systems II
Fixed Screen - Fine
Mesh
Off-shore Location (any
combination)
Traveling Screen -
Coarse Mesh
Traveling Screen - Fine
Mesh
Ohr.
Ohr.
24 hr.
Ohr.
Ohr.
24 hr.
48 hr.
84 hr.
96 hr.
Ohr.
8hr.
24 hr.
18
11
30
8
386
233
1
18
63
158
67
67
353149
6006
34
247
388
170
1236
101
120
2344712
37
30
615659
7520
68
487
1329
582
43
376
12842622
83
67
8914
288
0
8
0
0
1236
28
0
0
0
0
1948132
22158
342
1443
17719
5948
1236
187
2253
110000000
395
365
19531
1176
1
32
2
2
1236
71
1
7
1
1
37058
2432
9
69
17
8
1236
109
5
29
6
5
191926
7271
35
163
176
48
1236
130
45
296
22
20
1948132
22158
134
1443
2383
875
1236
187
420
11000000
237
213
Diversion (not impinged or entrained)
Behavioral Systems 1
Behavioral Systems II
Fixed Screen - Coarse
Mesh
Other technologies
Ohr.
Ohr.
Ohr.
Ohr.
64
2
12
2
7727
7
467
2311
31350
0
130
1795
0
7
148
1042
198157
8
561
3580
36
7
496
1042
86
7
518
2311
565
8
531
3580
44369
8
561
3580
Other
Traveling Screen -
Coarse Mesh
24 hr.
48 hr.
28
28
172
164
231
230
2
2
1040
1030
22
16
78
62
302
286
517
517
11B.3.3 Summaries of Percentage Change from Baseline in Mortality
Thirteen of the documents in Exhibit 11B-3 have some measure of mortality or survival
data under the given technology as well as under baseline (control) conditions. These
two sets of data were brought together to calculate a percentage change from baseline.
Within each document, this calculation was done on an individual species basis. For a
given document and study, if multiple values for a particular performance measure
existed for a given species, age category, and elapsed time to mortality for either the
technology or for baseline, then these values were averaged prior to calculating the
percent change from baseline.
Exhibits 11B-9 through 11B-11 summarize percentage change from baseline data by
technology. Percentage change from baseline was calculated for three types of
performance measures: mortality count, survival count, and percent mortality. Section
1 IB.7 contains the mean, minimum, and maximum percentage change from baseline
HB-30
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix B
calculation for each combination of document and study (test condition), as well as
facility, for each technology category.
Exhibit 11B-9. Descriptive Statistics
Count, by Technology Category and
on Percentage Change from Baseline in Mortality
Mortality Observation Time
Technology Category
Mortality
Obs. Time
N
Mean
Std.
Dev.
Min.
Max.
Percentiles
25tn
50tn
75tn
95tn
Entrainment
Barriers
Traveling Screen -
Coarse Mesh
Ohr.
Ohr.
8
1
12.8
-40.7
131.0
-304.4
-40.7
92.3
-40.7
25.3
-40.7
51.1
-40.7
81.0
-40.7
92.3
-40.7
Impingement
Barriers
Behavioral Systems II
Ohr.
Ohr.
1
1
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
Other
Traveling Screen -
Coarse Mesh
24 hr.
48 hr.
5
8
-146.3
-183.6
244.5
373.1
-550
-1075
66.7
66.7
-188.9
-165.6
-59.3
-94.4
0.0
30.0
66.7
66.7
Percentage change from baseline was calculated as 100*(Base//ne - Technology)/Baseline.
Exhibit 11B-10. Descriptive Statistics on Percentage Change from Baseline in Survival
Count, by Technology Category and Mortality Observation Time
Technology Category
Mortality
Obs. Time
N
Mean
Std.
Dev.
Min.
Max.
Percentiles
25in
50ln
75ln
95ln
Entrainment
Behavioral Systems II
Traveling Screen - Coarse
Mesh
Ohr.
Ohr.
96 hr.
12
1
1
6.9
3.4
8.2
23.2
-30.3
3.4
8.2
49.4
3.4
8.2
-6.7
3.4
8.2
6.5
3.4
8.2
16.6
3.4
8.2
49.4
3.4
8.2
Impingement
Behavioral Systems II
Traveling Screen - Coarse
Mesh
Ohr.
48 hr.
8
1
-6.4
-97.8
Diversion (not im
Behavioral Systems II
Ohr.
1
47.9
42.1
-74.3
-97.8
41.1
-97.8
-41.8
-97.8
2.4
-97.8
30.4
-97.8
41.1
-97.8
pinged or entrained)
47.9 1 47.9
47.9
47.9
47.9 1 47.9
Other
Traveling Screen - Coarse
Mesh
24 hr.
48 hr.
8
8
-44.6
-38.0
79.5
81.2
-220.0
-220.0
35.0
41.5
-66.9
-58.2
-22.6
-15.1
3.5
10.5
35.0
41.5
Percentage change from baseline was calculated as 100*(Base//ne - Technology)/Baseline. Survival could represent numbers
of organisms experiencing any positive outcome.
11B-31
-------
Chapter 11: Appendix B
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11B-11. Descriptive Statistics on Percentage Change from Baseline in Percent
Mortality, by Technology Category and Mortality Observation Time
Technology Category
Mortality
Obs. Time
N
Mean
Std.
Dev.
Min.
Max.
Percentiles
25in
50ln
75ln
95ln
Entrainment
Other technologies
Traveling Screen -
Coarse Mesh
Ohr.
Ohr.
96 hr.
2
1
1
-102.7
-7.3
-3.8
203.6
-246.7
-7.3
-3.8
41.2
-7.3
-3.8
-246.7
-7.3
-3.8
-102.7
-7.3
-3.8
41.2
-7.3
-3.8
41.2
-7.3
-3.8
Impingement
Traveling Screen -
Coarse Mesh
Traveling Screen - Fine
Mesh
48 hr.
Ohr.
48 hr.
96 hr.
1
15
16
20
50.9
-1021
-26.1
-22.3
3459.5
57.8
74.3
50.9
-13450
-133.3
-241.9
50.9
87.1
63.7
68.8
50.9
-278.0
-63.8
-33.1
50.9
-11.2
-15.9
3.9
50.9
52.4
18.2
21.9
50.9
87.1
63.7
52.6
Diversion (not impinged or entrained)
Behavioral Systems II
Ohr.
1
-3.6
-3.6 1 -3.6
-3.6
-3.6
-3.6
-3.6
Other
Traveling Screen -
Coarse Mesh
24 hr.
48 hr.
3
4
-70.3
-167.3
115.5
290.2
-179.3
-595.2
50.8
50.8
-179.3
-328.8
-82.3
-62.3
50.8
-5.7
50.8
50.8
Percentage change from baseline was calculated as 100*(Base//ne - Technology)/Baseline.
Among these performance measures, a percentage change from baseline that exceeds
zero indicates that levels were higher under baseline conditions than under conditions
with the technology in place. Under effective technologies, this would be expected to
occur with mortality-related performance measures.
As seen in Exhibits 11B-9 through 11B-11, the number of percentage change from
baseline values within a particular technology category was less than what was observed
in the previous summary tables. Exhibit 1 IB-10 shows that for entrainment, mean and
median values for percent change from baseline in survival counts are positive, indicating
that observed survival counts (from the three documents contributing entrainment data)
were higher under baseline conditions. Under the Behavioral Systems II technology
category, survival counts immediately following impingement (originating from
Documents 17 and 76) were close to being equivalent between baseline and technology
conditions, as the mean and median in Exhibit 11B-10 are close to zero. Exhibit 11B-11
shows that some values of percent change from baseline in percent mortality (i.e., for
some species) could be very large and negative. This occurs when percent mortality at
baseline is close to zero. This is one contributor to noting mean percentage changes from
baseline in Exhibit 11B-11 being negative for percent mortality.
As a result of the limited number of values, along with high uncertainty in the numbers
entering into the calculations and the interpretation of these numbers, percentage change
from baseline values were only summarized and not further statistically analyzed.
11B.4 Statistical Modeling
In order to assess and account for various factors that are likely to influence the
performance measures (percent mortality) for a given technology category, selected
performance measure data (pooled across documents and studies) were statistically
HB-32
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix B
analyzed using analysis of variance (ANOVA) modeling techniques. The objective of
this analysis was to yield a predicted average performance measure for specified levels of
the factors of interest. This analysis assumes two primary components of variability in
the performance measures: "between-study" variability (which represents how the
average value for a given performance measure may vary from one study to another as a
result of different test conditions, facilities, etc.), and "within-study" variability (which
represents how these values can vary within a study or facility, such as among different
species, time points, etc.).
Based upon numbers of available data (as noted in the data summaries of the previous
section), statistical modeling was applied only to percent mortality data associated with
impingement or entrainment. Separate fits of the statistical model were made to
impingement and entrainment data, as well as for each of the technology categories
having available data.
The ANOVA model used in this analysis had both "random" and "fixed" effects. When
data were available for multiple studies, the model included a random "study" effect to
allow for both between-study and within-study variability to be estimated. The model
had the following fixed effects:
• Season at the start of data collection (fall, winter, spring, summer);
• Age category offish (as noted within the document source); and
• Elapsed time from impingement/entrainment to mortality (in hours).
The fixed effects allowed the model to generate different performance predictions for
different combinations of fixed effects (e.g., different seasons of the year, different age
categories) present among the data. If data were available for only one level of a given
effect (e.g., one age category), then that effect was omitted from the model.
If p represents the proportion of outcomes classified as mortality, then the model assumed
that log(p/(l-//)) was a linear function of the fixed effects. The model assumed
independence in the value of the performance measure between different species and time
points within a study. We fit this model using the GLIMMIX procedure in the SAS
System.
The statistical model was successfully applied to the following sets of data:
• Entrainment data under fixed screens (fine mesh) (n=36 data points)
o Data were available for one study and season (fall), indicating that the random
study effect and fixed season effect were removed from the model.
• Entrainment data under the reduced intake flow (other) technology (n=177 data
points)
o Data were available for one season (fall) and mortality observation time
(0 hrs.), indicating that these two effects were removed from the model.
• Impingement data under traveling screens (coarse mesh) (n=683 data points)
• Impingement data under traveling screens (fine mesh) (n=254 data points)
11B-33
-------
Chapter 11: Appendix B § 316(b) Existing Facilities Proposed Rule -TDD
The ANOVA model was used to estimate mean predicted values for the performance
measure, for various combinations of fixed effects that were observed in the database.
These values are given in the last two columns of Exhibits 11B-12 through 11B-15, with
separate tables appearing for each model fitting (i.e., a particular technology category).
The fixed effects entering into each model appear in the other columns of this table, with
the levels of these effects corresponding to what was observed in the data.
Some conclusions made from the prediction estimates in Exhibits 11B-12 through 1 IB-
IS, are as follows (with references to statistical significance made at the 0.05 level):
• For entrainment under fixed screen (fine mesh), results in Exhibit 11B-12 suggest
that the model was only able to accurately estimate mean percent mortality for
juveniles (40 percent).
• Under reduced intake flow technology, average percent mortality following
entrainment were predicted only for selected age categories. Exhibit 11B-13
shows that among the early age categories (e.g., larvae, juvenile), this average
ranged from 27 to 34 percent. These averages did not differ significantly among
age categories at the 0.05 level.
• Under traveling screens with coarse mesh, average percent mortality for impinged
fish differed significantly among seasons of the year, age categories, and
mortality observation times following impingement. According to Exhibit 11B-
14, average percent mortality was highest in summer months, with one-half
mortality estimated, compared to nearly one-third mortality in other seasons.
Percent mortality averaged slightly above 50 percent for adults and juveniles,
while estimate mortality at 48 hours post-impingement is nearly twice that of
immediately following impingement.
• Like with coarse mesh screens, average percent mortality for impinged fish
differed significantly among seasons of the year, age categories, and mortality
observation times following impingement for traveling screens with fine mesh.
Similar trends in estimated average percent mortality among seasons of the year
were observed between fine and coarse mesh screens. These estimates cover a
wide range among the different age categories, reflecting in part the small sample
sizes associated with some age categories. The estimates at 8 and 24 hours post-
impingement are quite high and highly variable due to smaller sample sizes (from
a single study) compared to the other post-impingement time points. Thus, their
estimates should be interpreted with caution.
HB-34
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix B
Exhibit 11B-12. Mean Predicted Values for Percent Mortality Associated with
Entrainment Under Fixed Screen (Fine Mesh), as Estimated from Mixed Model
ANOVA Modeling
Factor
Age Category
Mortality Observation
Time
Level
Adult
Juvenile
Ohrs.
24 hrs.
48 hrs.
Mean Predicted
Percent Mortality
0.0
40.0
0.0
0.1
0.2
Exhibit 11B-13. Mean Predicted Values for Percent Mortality Associated with
Entrainment Under Reduced Intake Flows (Other), as Estimated from Mixed Model
ANOVA Modeling
Factor
Age Category
Level
Juvenile
Larvae
Not specified
Mean Predicted
Percent Mortality
34.2
27.9
26.6
Exhibit 11B-14. Mean Predicted Values for Percent Mortality Associated with
Impingement Under Traveling Screens (Coarse Mesh), as Estimated from Mixed
Model ANOVA Modeling
Factor
Season*
Age Category*
Mortality Observation
Time*
Level
Fall
Winter
Spring
Summer
Adult
Juvenile
Not specified
Adults/Juveniles
0 hrs.
18 hrs.
24 hrs.
48 hrs.
84 hrs.
96 hrs.
Mean Predicted
Percent Mortality
30.5
31.9
36.7
50.1
52.8
56.0
25.7
19.6
21.3
41.2
34.0
38.9
37.1
53.2
' Significant differences exist among means at the 0.05 level for selected levels of this factor.
11B-35
-------
Chapter 11: Appendix B
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11B-15. Mean Predicted Values for Percent Mortality Associated with
Impingement Under Traveling Screens (Fine Mesh), as Estimated from Mixed
Model ANOVA Modeling
Factor
Season*
Age Category*
Mortality Observation
Time*
Level
Fall
Winter
Spring
Summer
Adult
Eggs
Juvenile
Larvae
Megalops
Not specified
Adults/Juveniles
Zoea Stage 1
Zoea Unstaged
Postlarvae
Ohrs.
8hrs.
24 hrs.
48 hrs.
96 hrs.
Mean Predicted
Percent Mortality
39.4
23.1
52.5
58.6
2.8
78.0
2.3
87.8
24.7
69.3
84.3
4.5
39.3
96.1
7.8
90.9
94.0
5.7
22.3
* Significant differences exist among means at the 0.05 level for selected levels of this factor.
11 B. 5 Summaries of Percent Mortality, Percent Biomass, and
Percent Injury Data By Technology Category, Document,
and Study (Test Condition)
These exhibits provide additional detail for data summaries presented in Exhibits 11B-4
through 11B-6.
HB-36
-------
Exhibit 11B-16. Summary of Percent Mortality, Percent Biomass, and Percent Injury Data Associated with Entrainment, by
Technology Category, Document, and Study (Test Condition)
Technology Category
Barriers
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Other technologies
Reduced Intake Flows - Other
Reduced Intake Flows - Other
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Facility Name
Chalk Point Generating
Station
Dickerson
Potomac River
Morgantown
Green Island Hydroelectric
Project
Delmarva Ecological
Laboratory
Tracy Fish Collecting
Facility
Anclote Power Plant
Anclote Power Plant
Potrero Power Plant
Roseton Generating Station
Indian Point Generating
Station
Bowline Point Generating
Station
Lovett Generating Station
Indian Point Generating
Station
Danskammer Point
Generating Station
Roseton Generating Station
Indian Point Generating
Station
Bowline Point Generating
Station
Lovett Generating Station
Indian Point Generating
Station
Danskammer Point
Generating Station
Doc.
ID
49
49
49
49
47
167
193
4
4
18
130
130
130
130
130
130
130
130
130
130
130
130
Study
ID
14
10
12
13
2
253
182
58
59
101
216
217
218
219
220
221
222
223
224
225
226
227
Percent Immediate
Mortality
N
0
0
0
0
12
1
11
87
90
1
10
10
10
10
10
10
9
9
9
9
9
9
Mean
18.9
16.0
1.0
32.6
23.4
83.9
1.1
4.8
4.4
3.8
1.2
1.1
1.6
9.9
4.6
3.6
3.3
1.6
Min.
0.0
16.0
0.0
0.0
0.0
83.9
0.2
0.7
0.1
0.2
0.1
0.1
0.2
0.9
0.1
0.2
0.1
0.1
Max.
100.0
16.0
1.9
88.4
81.0
83.9
3.3
12.1
20.3
19.0
5.0
1.9
4.3
44.7
20.3
13.5
22.5
5.6
Percent Biomass
N
5
4
3
6
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
18.9
11.3
5.7
1.7
Min.
3.3
2.0
3.0
0.1
Max.
76.0
18.0
9.0
4.4
Percent Injury
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
C7
C7
to
-o
1
Q.
X'
oo
-------
ba
-------
Exhibit 11B-18. Summary of Percent Mortality, Percent Biomass, and Percent Injury Data Associated with Impingement, by
Technology Category, Document, and Study (Test Condition)
Technology Category
Barriers
Barriers
Barriers
Barriers
Behavioral Systems 1
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Off-shore Location (any
combination othe
Off-shore Location with
velocity Cap
Other technologies
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Facility Name
Bowline Point Generating
Station
Bowline Point Generating
Station
Chalk Point Generating
Station
Chalk Point Generating
Station
Brayton Point Generating
Station Unit 4
TV A laboratory
Test laboratory
Test laboratory
Oswego Steam Station
Various Coastal Stations in
the U.K.
No facility specified
Moss Landing
Moss Landing
Moss Landing
Surry Power Station
Dunkirk Steam Station
Calvert Cliffs Nuclear
Generating Station
Indian Point Generating
Station
Doc.
ID
38
38
126
126
46
169
171
195
193
78
146
18
18
18
43
44
46
46
Study
ID
106
189
113
114
119
151
152
117
158
46
73
102
103
104
18
8
78
82
Percent Immediate
Mortality
N
1
2
8
10
12
10
1
27
8
0
6
8
7
7
12
85
6
3
Mean
1.6
1.4
82.1
83.2
39.8
16.2
3.7
27.3
48.3
7.5
51.4
54.9
55.1
3.9
8.4
53.6
28.3
Min.
1.6
1.3
43.1
24.7
1.2
0.0
3.7
0.0
8.0
0.0
0.0
3.0
20.0
0.0
0.0
0.0
8.0
Max.
1.6
1.6
98.7
98.3
100.0
65.0
3.7
91.8
85.2
30.0
94.0
86.0
83.0
18.0
100.0
93.7
39.8
Percent Biomass
N
0
0
0
0
0
0
0
0
0
7
0
0
0
0
0
0
0
0
Mean
42.1
Min.
0.2
Max.
180.0
Percent Injury
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
s
•g
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-18. (Continued)
Technology Category
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Facility Name
Calvert Cliffs Nuclear
Generating Station
Huntley Steam Station
Quad Cities Generating
Station
Oyster Creek Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
JEA Northside Generating
System
JEA Northside Generating
System
Roseton Generating Station
JEA Northside Generating
System
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Bowline Point Generating
Station
Doc.
ID
46
51
60
62
65
66
136
136
136
136
138
138
138
138
143
143
143
163
Study
ID
118
1
9
19
50
71
68
70
72
129
47
48
49
51
88
89
90
153
Percent Immediate
Mortality
N
6
32
0
83
57
42
34
22
22
31
8
8
4
4
16
5
21
4
Mean
52.7
12.4
21.3
23.0
13.7
31.3
42.1
53.1
48.6
8.6
24.4
5.7
2.0
29.9
57.4
17.4
8.5
Min.
4.6
0.0
0.0
0.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
2.2
0.0
0.0
0.0
0.0
3.0
Max.
95.0
100.0
100.0
100.0
41.2
100.0
99.0
100.0
100.0
18.5
78.3
12.1
3.7
100.0
100.0
100.0
16.0
Percent Biomass
N
0
0
48
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
1.4
Min.
0.0
Max.
12.8
Percent Injury
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
to
-k
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-18. (Continued)
Technology Category
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Coarse
Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Roseton Generating Station
Oyster Creek Nuclear
Generating Station
Dunkirk Steam Station
Danskammer Point
Generating Station
Danskammer Point
Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Calvert Cliffs Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Barney Davis Power Station
Dunkirk Steam Station
Somerset Generating
Station
Le Blayais
Doc.
ID
163
164
193
193
193
193
193
193
193
193
193
193
205
205
205
205
43
46
64
73
Study
ID
154
150
159
168
169
172
173
174
175
176
177
178
236
237
238
239
21
79
5
6
Percent Immediate
Mortality
N
4
20
16
9
9
1
1
1
1
5
2
1
21
22
24
20
5
16
31
18
Mean
9.8
27.3
18.6
0.2
0.1
2.6
22.3
41.4
35.6
10.8
9.0
29.0
49.6
43.4
54.3
42.2
40.9
7.1
1.8
53.9
Min.
2.0
5.0
0.0
0.0
0.0
2.6
22.3
41.4
35.6
3.0
8.0
29.0
0.0
0.0
0.0
0.0
4.0
0.0
0.0
0.0
Max.
21.0
78.0
68.0
1.7
0.8
2.6
22.3
41.4
35.6
20.0
10.0
29.0
100.0
100.0
100.0
100.0
76.6
100.0
36.9
100.0
Percent Biomass
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
Percent Injury
N
0
20
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
28.1
Min.
5.0
Max.
64.0
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-18. (Continued)
Technology Category
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Barney Davis Power Station
Test laboratory
Test laboratory
Test laboratory
Prairie Island Nuclear
Generating Station
Salem Generating Station
Brunswick Steam Electric
Plant
Brunswick Steam Electric
Plant
Brayton Point Generating
Station Unit 4
Indian Point Generating
Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Dunkirk Steam Station
Dunkirk Steam Station
Brunswick Steam Electric
Plant
Brunswick Steam Electric
Plant
Brunswick Steam Electric
Plant
Doc.
ID
106
118
118
118
118
168
192
192
192
193
193
193
193
193
193
206
206
206
207
207
208
208
208
Study
ID
16
74
76
84
86
66
112
130
131
160
162
165
166
180
190
233
234
235
228
229
230
231
232
Percent Immediate
Mortality
N
11
8
8
8
8
34
1
0
0
33
31
16
11
12
11
7
7
7
56
11
8
5
10
Mean
51.7
24.1
87.6
3.4
4.4
6.8
24.4
55.6
43.4
14.1
30.1
25.2
36.6
35.4
39.1
32.1
1.5
0.2
48.9
63.1
39.0
Min.
1.2
0.0
57.1
0.0
0.0
0.0
24.4
0.0
8.0
0.0
3.0
0.9
0.0
1.0
10.0
12.0
0.0
0.0
9.8
13.7
6.3
Max.
98.5
56.8
100.0
8.7
34.9
45.5
24.4
100.0
90.0
54.2
90.1
98.3
100.0
84.0
71.0
84.0
25.5
2.7
100.0
100.0
100.0
Percent Biomass
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
Percent Injury
N
0
0
0
0
0
0
10
10
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
7.7
8.1
6.0
Min.
0.0
0.0
0.0
Max.
34.0
29.8
26.7
to
-k
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-19. Summary of Percent Mortality Data Associated with Impingement, by Technology Category, Document,
Study (Test Condition), and Mortality Observation Time
Technology Category
Barriers
Barriers
Barriers
Barriers
Behavioral Systems 1
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Off-shore Location (any
combination othe
Other technologies
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Facility Name
Bowline Point Generating Station
Bowline Point Generating Station
Chalk Point Generating Station
Chalk Point Generating Station
Brayton Point Generating Station Unit 4
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
Test laboratory
Arthur Kill Generating Station
Test laboratory
Oswego Steam Station
No facility specified
Moss Landing
Moss Landing
Moss Landing
Moss Landing
Moss Landing
Moss Landing
Surry Power Station
Dunkirk Steam Station
Dunkirk Steam Station
Calvert Cliffs Nuclear Generating Station
Indian Point Generating Station
Calvert Cliffs Nuclear Generating Station
Huntley Steam Station
Huntley Steam Station
Arthur Kill Generating Station
Arthur Kill Generating Station
Oyster Creek Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Doc.
ID
38
38
126
126
46
169
169
169
169
171
193
195
193
146
18
18
18
18
18
18
43
44
44
46
46
46
51
51
54
54
62
65
66
Study
ID
106
189
113
114
119
151
151
151
151
152
155
117
158
73
102
102
103
103
104
104
18
8
8
78
82
118
1
1
156
157
19
50
71
Mortality
Observation
Time
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
12hr.
24 hr.
48 hr.
Ohr.
24 hr.
Ohr.
Ohr.
Ohr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
Ohr.
24 hr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
24 hr.
24 hr.
Ohr.
Ohr.
Ohr.
Percent Mortality
N
1
2
8
10
12
10
10
10
10
1
30
27
8
6
8
8
7
7
7
7
12
85
85
6
3
6
32
32
54
49
83
57
42
Mean
1.6
1.4
82.1
83.2
39.8
16.2
27.2
29.1
30.7
3.7
47.7
27.3
48.3
7.5
51.4
64.0
54.9
76.6
55.1
72.9
3.9
8.4
15.1
53.6
28.3
52.7
12.4
17.5
14.3
14.7
21.3
23.0
13.7
Minimum
1.6
1.3
43.1
24.7
1.2
0.0
0.0
0.0
1.0
3.7
0.0
0.0
8.0
0.0
0.0
0.0
3.0
16.0
20.0
24.0
0.0
0.0
0.0
0.0
8.0
4.6
0.0
0.0
0.0
0.0
0.0
0.0
0.5
Maximum
1.6
1.6
98.7
98.3
100.0
65.0
91.0
91.0
91.0
3.7
100.0
91.8
85.2
30.0
94.0
100.0
86.0
100.0
83.0
100.0
18.0
100.0
100.0
93.7
39.8
95.0
100.0
100.0
78.1
100.0
100.0
100.0
41.2
s
•g
C7
C7
to
-o
1
Q.
X'
oo
-------
to
-k
Exhibit 11B-19. (Continued)
Technology Category
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Facility Name
Salem Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
JEA Northside Generating System
JEA Northside Generating System
Roseton Generating Station
JEA Northside Generating System
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Bowline Point Generating Station
Bowline Point Generating Station
Roseton Generating Station
Oyster Creek Nuclear Generating Station
Dunkirk Steam Station
Salem Generating Station
Indian Point Generating Station
Danskammer Point Generating Station
Danskammer Point Generating Station
Danskammer Point Generating Station
Danskammer Point Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Doc.
ID
85
136
136
136
136
138
138
138
138
143
143
143
143
143
143
143
163
163
163
164
193
193
193
193
193
193
193
193
193
193
193
193
193
193
193
Study
ID
147
68
70
72
129
47
48
49
51
88
88
88
89
90
90
90
153
153
154
150
159
161
163
168
168
169
169
172
172
173
173
174
174
175
175
Mortality
Observation
Time
48 hr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
96 hr.
Ohr.
Ohr.
24 hr.
96 hr.
Ohr.
96 hr.
Ohr.
Ohr.
Ohr.
18hr.
96 hr.
Ohr.
84 hr.
Ohr.
84 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Percent Mortality
N
1
34
22
22
31
8
8
4
4
16
5
6
5
21
8
8
4
2
4
20
16
26
44
9
9
9
9
1
1
1
1
1
1
1
1
Mean
20.7
31.3
42.1
53.1
48.6
8.6
24.4
5.7
2.0
29.9
38.8
66.7
57.4
17.4
26.1
54.7
8.5
41.0
9.8
27.3
18.6
31.7
42.6
0.2
13.6
0.1
17.4
2.6
10.3
22.3
29.3
41.4
58.2
35.6
38.6
Minimum
20.7
0.0
0.0
0.0
0.0
0.0
0.0
2.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
38.0
2.0
5.0
0.0
2.0
0.0
0.0
0.0
0.0
0.0
2.6
10.3
22.3
29.3
41.4
58.2
35.6
38.6
Maximum
20.7
100.0
99.0
100.0
100.0
18.5
78.3
12.1
3.7
100.0
100.0
100.0
100.0
100.0
100.0
100.0
16.0
44.0
21.0
78.0
68.0
82.0
100.0
1.7
80.2
0.8
78.5
2.6
10.3
22.3
29.3
41.4
58.2
35.6
38.6
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-19. (Continued)
Technology Category
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Bowline Point Generating Station
Bowline Point Generating Station
Bowline Point Generating Station
Bowline Point Generating Station
Bowline Point Generating Station
Bowline Point Generating Station
Potomac River
Calvert Cliffs Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Calvert Cliffs Nuclear Generating Station
Barney Davis Power Station
Dunkirk Steam Station
Brayton Point Generating Station Unit 4
Somerset Generating Station
Somerset Generating Station
Le Blayais
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Barney Davis Power Station
Test laboratory
Test laboratory
Test laboratory
Test laboratory
Prairie Island Nuclear Generating Station
Doc.
ID
193
193
193
193
193
193
196
205
205
205
205
43
46
46
64
64
73
106
118
118
118
118
118
118
118
118
118
118
118
118
168
192
192
192
192
193
Study
ID
176
176
177
177
178
178
91
236
237
238
239
21
79
83
5
5
6
16
74
74
74
76
76
76
84
84
84
86
86
86
66
112
112
130
131
160
Mortality
Observation
Time
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
96 hr.
48 hr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
48 hr.
Ohr.
96 hr.
Ohr.
Ohr.
Ohr.
48 hr.
96 hr.
Ohr.
48 hr.
96 hr.
Ohr.
48 hr.
96 hr.
Ohr.
48 hr.
96 hr.
Ohr.
Ohr.
48 hr.
48 hr.
48 hr.
Ohr.
Percent Mortality
N
5
2
2
2
1
1
33
21
22
24
20
5
16
12
31
31
18
11
8
8
8
8
4
4
8
8
8
8
8
8
34
1
10
10
10
33
Mean
10.8
41.0
9.0
72.5
29.0
81.0
24.0
49.6
43.4
54.3
42.2
40.9
7.1
43.5
1.8
28.2
53.9
51.7
24.1
10.5
24.7
87.6
57.6
57.8
3.4
9.5
37.0
4.4
5.5
18.8
6.8
24.4
1.2
1.9
1.5
55.6
Minimum
3.0
38.0
8.0
71.0
29.0
81.0
0.0
0.0
0.0
0.0
0.0
4.0
0.0
3.7
0.0
0.0
0.0
1.2
0.0
0.3
2.1
57.1
0.0
0.0
0.0
3.4
19.8
0.0
0.0
0.0
0.0
24.4
0.0
0.0
0.0
0.0
Maximum
20.0
44.0
10.0
74.0
29.0
81.0
100.0
100.0
100.0
100.0
100.0
76.6
100.0
100.0
36.9
100.0
100.0
98.5
56.8
17.8
54.1
100.0
89.1
89.9
8.7
16.1
57.2
34.9
28.2
85.0
45.5
24.4
4.3
4.7
4.5
100.0
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-19. (Continued)
Technology Category
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Salem Generating Station
Brunswick Steam Electric Plant
Brunswick Steam Electric Plant
Brayton Point Generating Station Unit 4
Brayton Point Generating Station Unit 4
Indian Point Generating Station
Indian Point Generating Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Brunswick Steam Electric Plant
Brunswick Steam Electric Plant
Brunswick Steam Electric Plant
Doc.
ID
193
193
193
193
193
193
193
206
206
206
207
207
207
207
207
207
208
208
208
Study
ID
162
165
166
180
181
190
190
233
234
235
228
228
228
229
229
229
230
231
232
Mortality
Observation
Time
Ohr.
Ohr.
Ohr.
Ohr.
48 hr.
Ohr.
96 hr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
8hr.
Ohr.
24 hr.
8hr.
Ohr.
Ohr.
Ohr.
Percent Mortality
N
31
16
11
12
12
11
11
7
7
7
56
56
56
11
11
11
8
5
10
Mean
43.4
14.1
30.1
25.2
37.3
36.6
78.8
35.4
39.1
32.1
1.5
28.0
22.4
0.2
31.3
22.5
48.9
63.1
39.0
Minimum
8.0
0.0
3.0
0.9
1.6
0.0
12.0
1.0
10.0
12.0
0.0
0.0
0.0
0.0
0.0
0.0
9.8
13.7
6.3
Maximum
90.0
54.2
90.1
98.3
100.0
100.0
100.0
84.0
71.0
84.0
25.5
100.0
100.0
2.7
100.0
100.0
100.0
100.0
100.0
to
-k
OS
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-20. Summary of Percent Mortality, Percent Biomass, and Percent Injury Data Associated with Diversion (not
impingement or entrainment), by Technology Category, Document, and Study (Test Condition)
Technology Category
Behavioral Systems 1
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Other technologies
Facility Name
San Onofre Nuclear
Generating Station (SONGS)
Heysham Power Station
Heysham Power Station
Heysham Power Station
Fawley Aquatic Research
Laboratory
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
Glenn-Colusa Irrigation
District Fish Screen
Doc.
ID
53
151
151
151
152
42
42
42
42
42
42
42
42
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
147
Study
ID
65
52
53
54
57
4
7
121
122
123
125
126
127
92
93
94
95
96
97
132
133
134
135
136
137
138
139
140
141
142
143
64
Percent Immediate
Mortality
N
64
1
1
1
2
4
0
4
2
2
0
0
0
11
17
19
11
17
19
11
11
17
17
24
21
11
11
17
17
24
21
2
Mean
24.6
100.0
77.4
38.2
96.3
0.6
0.2
0.2
1.2
0.7
5.1
6.9
1.1
6.4
4.6
2.5
5.9
10.2
16.0
16.2
26.1
5.0
12.3
10.8
15.4
14.2
24.2
74.2
Min.
0.0
100.0
77.4
38.2
96.2
0.0
0.0
0.0
0.9
0.0
0.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.6
0.0
66.0
Max.
100.0
100.0
77.4
38.2
96.5
1.2
0.4
0.4
1.4
3.6
22.0
29.5
4.7
46.5
19.9
11.1
20.4
34.3
82.6
47.0
76.6
22.1
54.4
66.6
82.0
61.9
86.5
82.3
Percent Biomass
N
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
Min.
Max.
Percent Injury
N
0
0
0
0
0
0
4
0
0
0
4
2
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Mean
1.9
4.5
13.1
22.1
Min.
1.5
3.5
10.8
21.7
Max.
2.6
5.8
15.4
22.5
s
•g
C7
C7
to
-o
1
Q.
X'
oo
-------
to
-k
00
Exhibit 11B-21. Summary of Percent Mortality Data Associated with Diversion (not impingement or en train men t), by
Technology Category, Document, Study (Test Condition), and Mortality Observation Time
Technology Category
Behavioral Systems 1
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Other technologies
Facility Name
San Onofre Nuclear Generating Station
(SONGS)
Heysham Power Station
Heysham Power Station
Heysham Power Station
Fawley Aquatic Research Laboratory
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
TVA laboratory
Glenn-Colusa Irrigation District Fish
Screen
Doc.
ID
53
151
151
151
152
42
42
42
42
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
170
147
Study
ID
65
52
53
54
57
4
121
122
123
92
93
94
95
96
97
132
133
134
135
136
137
138
139
140
141
142
143
64
Mortality
Observation
Time
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Percent Mortality
N
64
1
1
1
2
4
4
2
2
11
17
19
11
17
19
11
11
17
17
24
21
11
11
17
17
24
21
2
Mean
24.6
100.0
77.4
38.2
96.3
0.6
0.2
0.2
1.2
0.7
5.1
6.9
1.1
6.4
4.6
2.5
5.9
10.2
16.0
16.2
26.1
5.0
12.3
10.8
15.4
14.2
24.2
74.2
Minimum
0.0
100.0
77.4
38.2
96.2
0.0
0.0
0.0
0.9
0.0
0.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.6
0.0
66.0
Maximum
100.0
100.0
77.4
38.2
96.5
1.2
0.4
0.4
1.4
3.6
22.0
29.5
4.7
46.5
19.9
11.1
20.4
34.3
82.6
47.0
76.6
22.1
54.4
66.6
82.0
61.9
86.5
82.3
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-22. Summary of Percent Mortality Data for Outcomes Other than Impingement, Entrainment, or Diversion, by
Technology Category, Document, Study (Test Condition), and Mortality Observation Time
Technology Category
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Facility Name
California Delta Pumping Plant
California Delta Pumping Plant
Doc.
ID
61
61
Study
ID
11
11
Mortality
Observation
Time
24 hr.
48 hr.
Percent Mortality
N
16
16
Mean
12.0
21.2
Minimum
0.0
0.0
Maximum
53.5
69.6
C7
C7
to
-o
1
Q.
X'
oo
-------
Chapter 11: Appendix B § 316(b) 2011 Existing Facility Proposal- Technical Development Document
11B.6 Summary of Mortality and Survival Count Data by
Technology Category, Document, Study (Test Condition),
and Mortality Observation Time
These exhibits provide additional detail for data summaries presented in Exhibits 11B-7
and 11B-8.
HB-50
-------
Exhibit 11B-23. Summary of Mortality and Survival Count Data by Technology Category, Document, Study (Test Condition),
and Mortality Observation Time
Technology Category
Facility Name
Doc.
ID
Study
ID
Mortality
Obs.
Time
Mortality Counts
N
Mean
Mini-
mum
Maxi-
mum
Survival Counts
N
Mean
Mini-
mum
Maxi-
mum
Entrainment
Barriers
Barriers
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Lovett Generating Station
Lovett Generating Station
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Green Island Hydroelectric
Project
Green Island Hydroelectric
Project
Green Island Hydroelectric
Project
Delmarva Ecological
Laboratory
Potrero Power Plant
Potrero Power Plant
40
41
81
81
81
81
81
81
81
81
81
81
81
81
47
47
47
167
18
18
108
110
17
25
26
28
29
30
32
33
34
36
37
38
2
2
2
253
101
101
Impinc
Barriers
Barriers
Barriers
Bowline Point Generating
Station
Chalk Point Generating
Station
Chalk Point Generating
Station
38
49
49
106
15
120
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
48 hr.
Ohr.
Ohr.
96 hr.
4
4
0
0
0
0
0
0
0
0
0
0
0
0
12
12
12
1
1
0
661
2075
5
33
40
16
601
1
220
0
0
0
16
601
2432
6133
28
170
208
16
601
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
23572
22254
17762
388
467
396
573
781
487
748
839
928
115
56
23572
22254
17762
388
467
396
573
781
487
748
839
928
115
56
23572
22254
17762
388
467
396
573
781
487
748
839
928
115
56
jement
Ohr.
Ohr.
Ohr.
2
5
5
1941
863291
86421
232
41910
10459
3649
1948132
164738
0
0
0
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-23. (Continued)
Technology Category
Barriers
Barriers
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Fixed Screen - Fine Mesh
Fixed Screen - Fine Mesh
Off-shore Location (any
combination othe
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Facility Name
Chalk Point Generating
Station
Chalk Point Generating
Station
Hinkley Point Power Station
Heysham Power Station
Salem Generating Station
Test laboratory
Arthur Kill Generating Station
Oswego Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Huntley Steam Station
Huntley Steam Station
Arthur Kill Generating Station
Arthur Kill Generating Station
Oyster Creek Nuclear
Generating Station
Calvert Cliffs Nuclear
Generating Station
Salem Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
Roseton Generating Station
JEA Northside Generating
System
JEA Northside Generating
System
JEA Northside Generating
System
Hanford Generating Project
Hanford Generating Project
Mystic Generating Station
Mystic Generating Station
Doc.
ID
126
126
17
76
125
171
193
193
44
44
51
51
54
54
62
66
85
136
136
136
136
138
138
138
138
141
141
143
143
Study
ID
113
114
98
41
60
152
155
158
8
8
1
1
156
157
19
71
147
68
70
72
129
49
51
186
187
43
44
88
88
Mortality
Obs.
Time
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
Ohr.
Ohr.
24 hr.
Ohr.
24 hr.
24 hr.
24 hr.
Ohr.
Ohr.
48 hr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
Mortality Counts
N
0
0
0
0
4
1
0
8
85
85
32
32
0
0
83
42
0
34
0
0
31
0
0
50
41
26
11
11
5
Mean
10282
129
356
5
15
13
64
47
175844
1061
308
169
136
20
239
1
7
Mini-
mum
912
129
13
0
0
0
0
0
442
0
0
1
1
1
1
0
0
Maxi-
mum
20564
129
1647
62
142
282
866
1343
2229859
24759
5307
1646
1642
216
2398
5
31
Survival Counts
N
8
10
6
5
0
0
30
8
85
85
32
32
54
49
83
0
1
34
22
22
31
4
4
0
0
0
0
11
5
Mean
533702
208707
3624
8863
34
247
251
239
374
319
107
65
167
1236
352
2215
619
116
346
658
7
7
Mini-
mum
29908
8914
1176
288
0
8
0
0
0
0
1
0
0
1236
0
28
6
0
37
32
0
0
Maxi-
mum
1948132
1599762
7271
22158
342
1443
6002
5948
3357
2878
1331
721
6457
1236
4045
17719
3426
1442
524
1167
28
28
to
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
Exhibit 11B-23. (Continued)
Technology Category
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Mystic Generating Station
Dunkirk Steam Station
Indian Point Generating
Station
Danskammer Point
Generating Station
Danskammer Point
Generating Station
Danskammer Point
Generating Station
Danskammer Point
Generating Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Bowline Point Generating
Station
Monroe Power Plant
Barney Davis Power Station
Test laboratory
Prairie Island Nuclear
Generating Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Dunkirk Steam Station
Doc.
ID
143
143
143
143
193
193
193
193
193
193
193
193
193
193
193
193
103
168
192
193
207
207
207
207
207
Study
ID
88
90
90
90
159
163
168
168
169
169
176
176
177
177
178
178
188
66
112
160
228
228
228
229
229
Mortality
Obs.
Time
96 hr.
Ohr.
24 hr.
96 hr.
Ohr.
96 hr.
Ohr.
84 hr.
Ohr.
84 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
96 hr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
24 hr.
8hr.
Ohr.
24 hr.
Mortality Counts
N
6
16
8
8
16
44
0
0
0
0
0
0
0
0
0
0
58
34
0
33
0
0
0
0
0
Mean
2
0
4
2
105
34
43994
49
1604
Mini-
mum
0
0
0
0
0
0
2
0
0
Maxi-
mum
8
3
29
12
663
848
521500
853
20134
Survival Counts
N
6
16
8
8
16
44
9
9
9
9
5
2
2
2
1
1
0
34
1
33
56
56
56
11
11
Mean
1
6
3
3
372
85
95
95
107
107
1966
1323
1320
471
254
181
305
14665
375
59
31
38
38
26
Mini-
mum
0
0
0
0
1
0
28
28
38
38
412
393
256
237
254
181
5
14665
0
1
0
0
1
0
Maxi-
mum
2
26
10
11
2877
1839
145
145
187
187
5891
2253
2383
705
254
181
3868
14665
5765
505
365
395
250
213
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-23. (Continued)
Technology Category
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Facility Name
Dunkirk Steam Station
Brunswick Steam Electric
Plant
Brunswick Steam Electric
Plant
Brunswick Steam Electric
Plant
Doc.
ID
207
208
208
208
Study
ID
229
230
231
232
Mortality
Obs.
Time
8hr.
Ohr.
Ohr.
Ohr.
Mortality Counts
N
0
0
0
0
Mean
Mini-
mum
Maxi-
mum
Survival Counts
N
11
8
5
10
Mean
33
27201250
30400000
81337
Mini-
mum
0
0
0
0
Maxi-
mum
237
110000000
100000000
268569
Diversion (not impinged or entrained)
Behavioral Systems 1
Behavioral Systems II
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Fixed Screen - Coarse Mesh
Other technologies
San Onofre Nuclear
Generating Station (SONGS)
Fawley Aquatic Research
Laboratory
Elwha Dam
Elwha Dam
Elwha Dam
Elwha Dam
Glenn-Colusa Irrigation
District Fish Screen
53
152
42
42
42
42
147
65
57
4
121
122
123
64
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
0
0
0
0
0
0
0
64
2
4
4
2
2
2
7727
7
509
521
195
550
2311
0
7
482
509
148
538
1042
198157
8
528
534
241
561
3580
Other
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
Traveling Screen - Coarse Mesh
California Delta Pumping
Plant
California Delta Pumping
Plant
California Delta Pumping
Plant
California Delta Pumping
Plant
61
61
61
61
11
11
24
24
24 hr.
48 hr.
24 hr.
48 hr.
16
16
12
12
9
19
4
8
0
0
0
0
52
82
25
32
16
16
12
12
191
181
145
142
5
5
2
2
1040
1030
517
517
to
TO
3
Q_
x"
OD
cm
CO
TO
Q.
70
C7
C7
-------
11B.7 Summaries of Percentage Change from Baseline in
Mortality and Survival Counts, and Percent Survival, By
Technology Category, Document, and Study (Test
Condition)
These exhibits provide additional detail for data summaries presented in Exhibits 11B-9
through 11B-11.
-------
to
<1<1
OS
Exhibit 11B-24. Summary of Calculated Percentage Change from Baseline in Immediate Mortality and Survival Counts, by
Technology Category, Document, and Study (Test Condition)
Technology Category
Facility Name
Doc.
ID
Study
ID1
Change from Baseline in
Immediate Mortality Counts
N
Mean
Min.
Max.
Change from Baseline in
Immediate Survival Counts
N
Mean
Min.
Max.
Entrainment
Barriers
Barriers
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Traveling Screen - Coarse Mesh
Lovett Generating Station
Lovett Generating Station
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Pine Hydroelectric Project
Potrero Power Plant
40
41
81
81
81
81
81
81
81
81
81
81
81
81
18
108
110
17
25
26
28
29
30
32
33
34
36
37
38
101
4
4
0
0
0
0
0
0
0
0
0
0
0
0
1
56.9
-31.2
-40.7
24.2
-304.4
-40.7
92.3
84.7
-40.7
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
Impingement
Barriers
Behavioral Systems II
Behavioral Systems II
Behavioral Systems II
Bowline Point Generating
Station
Hinkley Point Power Station
Heysham Power Station
Salem Generating Station
38
17
76
125
106
98
41
60
1
0
0
1
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
0
3
5
0
-52.6
21.3
-74.3
-1.5
-33.0
41.1
Diversion (not impingement or entrainment)
Behavioral Systems II
Fawley Aquatic Research
Laboratory
152
57
0
1
47.9
47.9
47.9
TO
3
Q_
x"
OD
cm
CO
C?
IQ
~n
o
1 Study ID associated with test conditions when the technology is in place.
TO
Q.
70
C7
C7
-------
Exhibit 11B-25. Summary of Calculated Percentage Change from Baseline in Mortality and Survival Related Measures, by
Technology Category, Document, Study (Test Condition), and Mortality Observation Time
Technology
Category
Facility Name
Doc.
ID
Study
ID1
Mortal-
ity
Obser-
vation
Time
Change from Baseline in
Mortality Counts
N
Mean
Mini-
mum
Maxi-
mum
Change from Baseline in
Survival Counts
N
Mean
Mini-
mum
Maxi-
mum
Change from Baseline in
Percent Mortality
N
Mean
Mini-
mum
Maxi-
mum
Entrainment
Barriers
Barriers
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Other
technologies
Traveling Screen
- Coarse Mesh
Lovett Generating
Station
Lovett Generating
Station
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Pine Hydroelectric
Project
Tracy Fish
Collecting Facility
Potrero Power
Plant
40
41
81
81
81
81
81
81
81
81
81
81
81
81
193
18
108
110
17
25
26
28
29
30
32
33
34
36
37
38
182
101
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
Ohr.
4
4
0
0
0
0
0
0
0
0
0
0
0
0
0
1
56.9
-31.2
-40.7
24.2
-304.4
-40.7
92.3
84.7
-40.7
0
0
1
1
1
1
1
1
1
1
1
1
1
1
0
1
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
-30.3
-23.0
1.9
14.3
-3.1
12.6
40.5
18.9
49.4
11.1
0.2
-10.3
3.4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
1
-102.7
-7.3
-246.7
-7.3
41.2
-7.3
s
•g
C7
C7
to
-o
1
Q.
X'
oo
-------
Exhibit 11B-25. (Continued)
Technology
Category
Traveling Screen
- Coarse Mesh
Facility Name
Potrero Power
Plant
Doc.
ID
18
Study
ID1
101
Mortal-
ity
Obser-
vation
Time
96 hr.
Change from Baseline in
Mortality Counts
N
0
Mean
Mini-
mum
Maxi-
mum
Change from Baseline in
Survival Counts
N
1
Mean
8.2
Mini-
mum
8.2
Maxi-
mum
8.2
Change from Baseline in
Percent Mortality
N
1
Mean
-3.8
Mini-
mum
-3.8
Maxi-
mum
-3.8
Impingement
Barriers
Behavioral
Systems II
Behavioral
Systems II
Behavioral
Systems II
Traveling Screen
- Coarse Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Traveling Screen
- Fine Mesh
Bowline Point
Generating Station
Hinkley Point
Power Station
Heysham Power
Station
Salem Generating
Station
Salem Generating
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
Big Bend Power
Station
38
17
76
125
85
118
118
118
118
118
118
118
118
118
118
118
106
98
41
60
147
74
74
74
76
76
76
84
84
84
86
86
Ohr.
Ohr.
Ohr.
Ohr.
48 hr.
Ohr.
48 hr.
96 hr.
Ohr.
48 hr.
96 hr.
Ohr.
48 hr.
96 hr.
Ohr.
96 hr.
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
-136.1
-0.3
-136.1
-0.3
-136.1
-0.3
0
3
5
0
1
0
0
0
0
0
0
0
0
0
0
0
-52.6
21.3
-97.8
-74.3
-1.5
-97.8
-33.0
41.1
-97.8
0
0
0
0
1
4
6
7
6
3
3
4
7
8
1
2
50.9
-3865.9
-59.8
-53.3
-24.5
23.2
22.9
62.3
-18.3
-9.6
52.4
-32.8
50.9
-13450.0
-120.5
-241.9
-61.6
10.9
10.1
22.2
-133.3
-178.9
52.4
-87.1
50.9
-278.0
14.3
25.3
15.7
36.4
36.4
87.1
63.7
68.8
52.4
21.6
to
^-n
Oo
TO
3
Q_
x"
OD
cm
CO
IQ
~n
o
TO
Q.
70
C7
C7
-------
Exhibit 11B-25. (Continued)
Technology
Category
Facility Name
Doc.
ID
Study
ID1
Mortal-
ity
Obser-
vation
Time
Change from Baseline in
Mortality Counts
N
Mean
Mini-
mum
Maxi-
mum
Change from Baseline in
Survival Counts
N
Mean
Mini-
mum
Maxi-
mum
Change from Baseline in
Percent Mortality
N
Mean
Mini-
mum
Maxi-
mum
Diversion (not impingement or entrainment)
Behavioral
Systems II
Fawley Aquatic
Research
Laboratory
152
57
Ohr.
0
1
47.9
47.9
47.9
1
-3.6
-3.6
-3.6
Other
Traveling Screen
- Coarse Mesh
Traveling Screen
- Coarse Mesh
Traveling Screen
- Coarse Mesh
Traveling Screen
- Coarse Mesh
California Delta
Pumping Plant
California Delta
Pumping Plant
California Delta
Pumping Plant
California Delta
Pumping Plant
61
61
61
61
11
11
24
24
24 hr.
48 hr.
24 hr.
48 hr.
3
4
2
4
-246.3
-348.8
3.7
-18.3
-550.0
-1075.0
-59.3
-166.7
0.0
0.0
66.7
66.7
4
4
4
4
-94.8
-83.0
5.6
7.0
-220.0
-220.0
-19.7
-19.5
-25.4
4.3
35.0
41.5
3
4
0
0
-70.3
-167.3
-179.3
-595.2
50.8
50.8
C7
C7
1 Study ID associated with test conditions when the technology is in place.
to
-o
1
Q.
X'
oo
-------
to
Exhibit 11B-26. Summary of Calculated Percentage Change from Baseline in Percent Immediate Mortality, by Technology
Category, Document, and Study (Test Condition)
Technology Category
Facility Name
Doc. ID
Study ID1
Change from Baseline in Percent
Immediate Mortality
N
Mean
Min.
Max.
Entrainment
Other technologies
Traveling Screen - Coarse Mesh
Tracy Fish Collecting Facility
Potrero Power Plant
193
18
182
101
2
1
-102.7
-7.3
-246.7
-7.3
41.2
-7.3
Impingement
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Traveling Screen - Fine Mesh
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
Big Bend Power Station
118
118
118
118
74
76
84
86
4
6
4
1
-3865.9
-24.5
62.3
52.4
-13450.0
-61.6
22.2
52.4
-278.0
15.7
87.1
52.4
Diversion (not impingement or entrainment)
Behavioral Systems II |Fawley Aquatic Research Laboratory
152
57
1
-3.6 | -3.6 | -3.6
TO
3
Q_
x"
OD
Study ID associated with test conditions when the technology is in place.
cm
CO
C?
IQ
~n
o
TO
Q.
70
C7
C7
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix C
Appendix C to Chapter 11: Impingement and
Entrainment Data
The tables in this appendix list the impingement and entrainment data evaluated in
Chapter 11.
• Exhibit 11C-1 lists the impingement data.
• Exhibitl 1C-2 lists the entrainment data.
11C-1
-------
n
Exhibit 11C-1. Impingement Mortality Data Used to Develop the Proposed Limitations
Study
ID
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
Facility
Name
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Species Name
Alewife
American eel
American shad
Atlantic Croaker
Atlantic herring
Atlantic silverside
Atlantic tomcod
Bay Anchovy
Black Sea bass
Blueback Herring
Bluecrab
Bluefish
Butterfish
Conger eel
Crevalle Jack
Gunner
Cusk eel
Feather blenny
Gizzard shad
Gray snapper
Grubby
Lookdown
Mackeral
Menhaden
Mummichog
Naked Goby
Northern kingfish
Northern pipefish
Northern puffer
Northern searobin
Pinfish
Rainbow Smelt
Red hake
Rock gunnel
Sea horse
Seaboard goby
Silver hake
Silver perch
Smallmouth flounder
Life
Stage
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Start
Month
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Start
Year
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
End
Season
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
End
Month
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
End
Year
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
#
Impinged
That
Died
2
1
7
0
321
14
1
490
1
355
1
6
15
1
0
0
1
0
0
0
0
0
1
12
7
2
0
3
0
4
0
1
0
0
0
0
4
2
0
#
Impinged
That
Survived
35
6
24
1
90
617
18
346
16
1331
657
2
39
6
1
8
4
1
2
1
7
6
2
37
84
1
1
89
25
129
1
56
1
1
47
22
18
24
1
Total #
Impinged
37
7
31
1
411
631
19
836
17
1686
658
8
54
7
1
8
5
1
2
1
7
6
3
49
91
3
1
92
25
133
1
57
1
1
47
22
22
26
1
%
Impingement
Mortality
5.4
14.3
22.6
0.0
78.1
2.2
5.3
58.6
5.9
21.1
0.2
75.0
27.8
14.3
0.0
0.0
20.0
0.0
0.0
0.0
0.0
0.0
33.3
24.5
7.7
66.7
0.0
3.3
0.0
3.0
0.0
1.8
0.0
0.0
0.0
0.0
18.2
7.7
0.0
%
Impingement
Survival
94.6
85.7
77.4
100.0
21.9
97.8
94.7
41.4
94.1
78.9
99.8
25.0
72.2
85.7
100.0
100.0
80.0
100.0
100.0
100.0
100.0
100.0
66.7
75.5
92.3
33.3
100.0
96.7
100.0
97.0
100.0
98.2
100.0
100.0
100.0
100.0
81.8
92.3
100.0
cm
U)
•g
(A
TO
Q-
70
C7
C7
-------
Exhibit 11C-1. (Continued)
Study
ID
156
156
156
156
156
156
156
156
156
156
156
156
156
156
156
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
Facility
Name
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Species Name
Spot
Spotted hake
Star gazer
Striped Bass
Striped anchovy
Striped cusk-eel
Striped killifish
Striped searobin
Summer flounder
Tautog (blackfish)
Threespine
stickleback
Weakfish
White perch
Windowpane flounder
Winter flounder
Alewife
American eel
American shad
Atlantic Croaker
Atlantic herring
Atlantic silverside
Atlantic tomcod
Banded killifish
Bay Anchovy
Black Sea bass
Blueback Herring
Bluecrab
Bluefish
Butterfish
Conger eel
Crevalle Jack
Gunner
Gray snapper
Grubby
Lookdown
Menhaden
Mummichog
Northern pipefish
Northern puffer
Northern searobin
Life
Stage
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Start
Month
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Start
Year
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
End
Season
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
End
Month
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
End
Year
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
#
Impinged
That
Died
0
7
3
2
9
0
7
1
5
0
2
64
7
1
6
1
0
3
1
15
3
0
0
93
1
16
3
2
17
0
0
0
0
0
1
10
4
0
0
5
#
Impinged
That
Survived
15
48
1
22
6
1
48
4
8
2
878
695
61
21
197
30
4
11
0
10
329
8
4
100
12
355
368
2
54
4
1
8
1
2
2
24
16
19
8
47
Total #
Impinged
15
55
4
24
15
1
55
5
13
2
880
759
68
22
203
31
4
14
1
25
332
8
4
193
13
371
371
4
71
4
1
8
1
2
3
34
20
19
8
52
%
Impingement
Mortality
0.0
12.7
75.0
8.3
60.0
0.0
12.7
20.0
38.5
0.0
0.2
8.4
10.3
3.5
3.0
3.2
0.0
21.4
100.0
60.0
0.9
0.0
0.0
48.2
7.7
4.3
0.8
50.0
23.9
0.0
0.0
0.0
0.0
0.0
33.3
29.4
20.0
0.0
0.0
9.6
%
Impingement
Survival
100.0
87.3
25.0
91.7
40.0
100.0
87.3
80.0
61.5
100.0
99.8
91.6
89.7
96.5
97.0
96.8
100.0
78.6
0.0
40.0
99.1
100.0
100.0
51.8
92.3
95.7
99.2
50.0
76.1
100.0
100.0
100.0
100.0
100.0
66.7
70.6
80.0
100.0
100.0
90.4
m
x
'
-o
3
C7
C7
o
-o
-o
TO
3
Q.
x'
-------
n
-k
Exhibit 11C-1. (Continued)
Study
ID
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
157
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Facility
Name
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Arthur Kill
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Species Name
Orange filefish
Rainbow Smelt
Red hake
Rock gunnel
Sea horse
Seaboard goby
Silver hake
Silver perch
Smallmouth flounder
Spot
Spotted hake
Star gazer
Striped Bass
Striped anchovy
Striped killifish
Striped searobin
Summer flounder
Tautog (blackfish)
Threespine
stickleback
Weakfish
White perch
Windowpane flounder
Winter flounder
Bluegill
Bluntnose Minnow
Brook Silverside
Brown Bullhead
Carp
Channel Catfish
Emerald Shiner
Freshwater Drum
Gizzard shad
Gizzard shad
Goldfish
Largemouth Bass
Log Perch
Longnose Dace
Pumpkinseed
Rainbow Smelt
Rainbow Trout
Life
Stage
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Adult
Juvenile
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Start
Month
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
Start
Year
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1994
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
End
Season
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
End
Month
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
End
Year
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1995
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
#
Impinged
That
Died
0
0
0
0
0
0
0
0
0
1
1
2
2
9
1
0
7
0
0
24
6
2
5
0
1
0
0
0
0
111
0
0
21
0
0
0
0
0
103
0
#
Impinged
That
Survived
1
21
5
1
27
2
15
18
1
9
18
5
7
9
23
2
7
3
639
721
35
11
174
25
5
1
4
1
5
5948
0
11
1456
6
1
10
2
14
359
2
Total #
Impinged
1
21
5
1
27
2
15
18
1
10
19
7
9
18
24
2
14
3
639
745
41
13
179
25
6
1
4
1
5
6072
1
12
1477
6
1
10
2
14
473
2
%
Impingement
Mortality
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
10.0
5.3
28.6
22.2
50.0
4.2
0.0
50.0
0.0
0.0
3.2
14.6
15.4
2.8
0.0
16.7
0.0
0.0
0.0
0.0
2.0
100.0
8.3
1.4
0.0
0.0
0.0
0.0
0.0
24.1
0.0
%
Impingement
Survival
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
100.0
90.0
94.7
71.4
77.8
50.0
95.8
100.0
50.0
100.0
100.0
96.8
85.4
84.6
97.2
100.0
83.3
100.0
100.0
100.0
100.0
98.0
0.0
91.7
98.6
100.0
100.0
100.0
100.0
100.0
75.9
100.0
cm
U)
•g
(A
TO
Q-
70
C7
C7
-------
Exhibit 11C-1. (Continued)
Study
ID
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
Facility
Name
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Species Name
Rock bass
Round Goby
Sculpin
Smallmouth Bass
Spottail Shiner
Stonecat
Trout Perch
White bass
White perch
White Sucker
Yellow Perch
Bluegill
Emerald Shiner
Freshwater Drum
Gizzard shad
Gizzard shad
Largemouth Bass
Rainbow Smelt
Rainbow Smelt
Rock bass
Sculpin
Shorthead Redhorse
Spottail Shiner
Trout Perch
White bass
Yellow Perch
Alewife
Black Crappie
Bluegill
Bluntnose Minnow
Emerald Shiner
Fathead Minnow
Freshwater Drum
Gizzard shad
Gizzard shad
Johnny Darter
Quilback Sucker
Rainbow Smelt
Rainbow Trout
Rock bass
Round Goby
Life
Stage
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Adult
Juvenile
N.S.
Adult
Juvenile
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Adult
Juvenile
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Start
Month
11
11
11
11
11
11
11
11
11
11
11
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
Start
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1998
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
End
Season
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
Spring
End
Month
11
11
11
11
11
11
11
11
11
11
11
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
End
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
#
Impinged
That
Died
0
0
0
1
3
0
0
2
0
0
1
0
68
0
4
88
0
44.5
50.5
2
0
0
1
3
0
0
142
0
0
0
104
0
1
0
68
0
1
115
0
0
0
#
Impinged
That
Survived
157
4
5
5
259
6
1
145
45
4
176
3
3669
1
86
1825
1
377.6
133.4
22
1
1
296
5
1
66
78
1
1
1
2436
1
0
2
137
2
0
201
3
4
2
Total #
Impinged
157
4
5
6
263
6
1
147
45
4
178
3
3738
1
93
1927
1
426.1
187.9
24
1
1
297
8
1
66
260
1
1
1
2564
1
1
3
211
2
1
318
3
4
2
%
Impingement
Mortality
0.0
0.0
0.0
16.7
1.5
0.0
0.0
1.4
0.0
0.0
1.1
0.0
1.8
0.0
7.5
5.3
0.0
11.4
29.0
8.3
0.0
0.0
0.3
37.5
0.0
0.0
70.0
0.0
0.0
0.0
5.0
0.0
100.0
33.3
35.1
0.0
100.0
36.8
0.0
0.0
0.0
%
Impingement
Survival
100.0
100.0
100.0
83.3
98.5
100.0
100.0
98.6
100.0
100.0
98.9
100.0
98.2
100.0
92.5
94.7
100.0
88.6
71.0
91.7
100.0
100.0
99.7
62.5
100.0
100.0
30.0
100.0
100.0
100.0
95.0
100.0
0.0
66.7
64.9
100.0
0.0
63.2
100.0
100.0
100.0
m
x
'
-o
3
C7
C7
o
-o
-o
TO
3
Q.
x'
-------
n
"is
Exhibit 11C-1. (Continued)
Study
ID
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Facility
Name
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Dunkirk
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Species Name
Sculpin
Spottail Shiner
Trout Perch
White bass
White perch
Yellow Perch
Alewife
Bluegill
Emerald Shiner
Freshwater Drum
Gizzard shad
Largemouth Bass
Log Perch
Rainbow Smelt
Rock bass
Round Goby
Smallmouth Bass
Spottail Shiner
Stonecat
Trout Perch
White bass
White perch
Yellow Perch
Alewife
Black Crappie
Brook Silverside
Darters
Emerald Shiner
Gizzard shad
Goldfish
Pumpkinseed
Rainbow Smelt
Rock bass
Smallmouth Bass
Spottail Shiner
White bass
White perch
Yellow Perch
Alewife
Bluntnose Minnow
Darters
Life
Stage
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Spring
Spring
Spring
Spring
Spring
Spring
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Summer
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Winter
Winter
Winter
Start
Month
4
4
4
4
4
4
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
1
1
1
Start
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
End
Season
Spring
Spring
Spring
Spring
Spring
Spring
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Fall
Winter
Winter
Winter
End
Month
4
4
4
4
4
4
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
1
1
1
End
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
#
Impinged
That
Died
0
1
3
0
0
0
10
0
14
0
84
0
0
39
1
0
1
31
0
1
1
0
0
139
0
0
0
14
2
0
0
866
0
0
3
1
0
0
4
0
0
#
Impinged
That
Survived
2
130
48
1
2
1
0
5
31
0
239
3
1
9
298
10
17
357
0
0
5
22
13
41
1
1
5
611
63
1
1
875
178
6
226
124
4
1
0
3
2
Total #
Impinged
2
132
51
1
2
1
12
5
46
1
338
3
1
48
300
10
18
393
2
1
6
22
14
183
1
1
5
628
65
1
1
1824
180
6
231
127
4
1
30
3
2
%
Impingement
Mortality
0.0
1.5
5.9
0.0
0.0
0.0
100.0
0.0
32.6
100.0
29.3
0.0
0.0
81.2
0.7
0.0
5.6
9.2
100.0
100.0
16.7
0.0
7.1
77.6
0.0
0.0
0.0
2.7
3.1
0.0
0.0
52.0
1.1
0.0
2.2
2.4
0.0
0.0
100.0
0.0
0.0
%
Impingement
Survival
100.0
98.5
94.1
100.0
100.0
100.0
0.0
100.0
67.4
0.0
70.7
100.0
100.0
18.8
99.3
100.0
94.4
90.8
0.0
0.0
83.3
100.0
92.9
22.4
100.0
100.0
100.0
97.3
96.9
100.0
100.0
48.0
98.9
100.0
97.8
97.6
100.0
100.0
0.0
100.0
100.0
cm
U)
•g
(A
TO
Q-
70
C7
C7
-------
Exhibit 11C-1. (Continued)
Study
ID
1
1
1
1
1
1
1
1
1
1
1
1
1
Facility
Name
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Huntley
Species Name
Emerald Shiner
Gizzard shad
Gizzard shad
Rainbow Smelt
Rainbow Smelt
Redhorse sucker
Rock bass
Smallmouth Bass
Spottail Shiner
Trout Perch
White perch
White Sucker
Yellow Perch
Life
Stage
N.S.
Adult
Juvenile
Adult
Juvenile
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
N.S.
Delayed
Mortality
(hrs.)
24
24
24
24
24
24
24
24
24
24
24
24
24
Start
Season
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Start
Month
1
1
1
1
1
1
1
1
1
1
1
1
1
Start
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
End
Season
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
Winter
End
Month
1
1
1
1
1
1
1
1
1
1
1
1
1
End
Year
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
1999
#
Impinged
That
Died
33
0
57
83
379
0
1
0
0
0
4
0
0
#
Impinged
That
Survived
2146
0
16
1588.7
1289.3
2
17
3
17
67
3
11
20
Total #
Impinged
2201
3
315
1684.9
1733.1
2
19
3
18
67
8
11
20
%
Impingement
Mortality
2.5
100.0
94.9
5.2
23.3
0.0
10.5
0.0
5.6
0.0
62.5
0.0
0.0
%
Impingement
Survival
97.5
0.0
5.1
94.8
76.7
100.0
89.5
100.0
94.4
100.0
37.5
100.0
100.0
m
x
'
-o
3
C7
C7
N.S. = No specified age category.
O
-o
-o
TO
3
Q.
X
-------
Exhibit 11C-2. Entrainment Data Evaluated in Chapter 11
Study
ID
244
240
206
206
206
206
206
206
206
206
207
207
207
207
207
207
207
207
208
208
208
208
208
208
208
208
208
209
209
209
209
209
209
209
209
209
210
210
210
210
Year
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1982
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
Facility Name or
Location
Brunswick
Logan
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Techno-
logy
TS-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
Screen Mesh Size, Slot Velocity
(Larval Length)
1 mm (5-7 mm length)
1 mm (8-10 mm length)
1 mm (11-14 mm length)
1 mm (>= 15 mm length)
1 mm (<= 4 mm length)
1 mm (5-6 mm length)
1 mm (7-8 mm length)
1 mm (>=9 mm length)
2 mm (5-7 mm length)
2 mm (8-10 mm length)
2 mm (11-14 mm length)
2 mm (>= 15 mm length)
2 mm (<= 4 mm length)
2 mm (5-6 mm length)
2 mm (7-8 mm length)
2 mm (>=9 mm length)
1 mm (<= 4 mm length)
1 mm (5-7 mm length)
1 mm (8-10 mm length)
1 mm (11-14 mm length)
1 mm (>= 15 mm length)
1 mm (<= 4 mm length)
1 mm (5-6 mm length)
1 mm (7-8 mm length)
1 mm (>=9 mm length)
2 mm, 0.2 m/s (<= 4 mm length)
2 mm, 0.2 m/s (5-7 mm length)
2 mm, 0.2 m/s (8-10 mm length)
2 mm, 0.2 m/s (11-14 mm length)
2 mm, 0.2 m/s (>= 15 mm length)
2 mm, 0.2 m/s (<= 4 mm length)
2 mm, 0.2 m/s (5-6 mm length)
2 mm, 0.2 m/s (7-8 mm length)
2 mm, 0.2 m/s (>=9 mm length)
3 mm
3 mm (<= 4 mm length)
3 mm (5-7 mm length)
3 mm (8-10 mm length)
Species Name
All fish
All fish
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Life Stage
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Density
Units
#/1000m3
#
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
Density
Behind
Technology
99
41
0.0
0.0
0.0
1.5
1.5
6.0
5.8
35.8
0.0
1.5
10.5
15.0
13.5
19.5
16.5
64.6
9.2
10.8
1.0
0.0
0.0
562.5
66.5
3.9
1.9
21.0
9.2
1.6
0.0
0.4
513.4
81.6
9.6
4.4
1707.0
13.6
11.3
2.6
Density in
Front of
Technology
543
637
4.1
1.6
31.1
57.3
17.2
22.9
38.5
201.5
4.1
1.6
31.1
57.3
17.2
22.9
38.5
201.5
9.6
20.1
7.7
1.3
3.3
535.7
148.7
49.7
49.1
9.6
20.1
7.7
1.3
3.3
535.7
148.7
49.7
49.1
2341.0
9.6
20.1
7.7
Percent
Reduction
81.77
93.56
100.00
100.00
100.00
97.38
91.28
73.80
84.94
82.23
100.00
6.25
66.24
73.82
21.51
14.85
57.14
67.94
4.17
46.27
87.01
100.00
100.00
-5.00
55.28
92.15
96.13
-118.75
54.23
79.22
100.00
87.88
4.16
45.12
80.68
91.04
27.08
-41.67
43.78
66.23
cm
U)
TO
Q-
70
C7
C7
-------
Exhibit 11C-2. (Continued)
Study
ID
210
210
210
210
210
210
241
241
241
241
241
241
241
241
241
242
242
242
242
242
242
242
242
242
243
243
243
243
243
243
243
243
243
200
200
200
200
200
200
200
Year
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
1983
Facility Name or
Location
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chalk Point
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Techno-
logy
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
Screen Mesh Size, Slot Velocity
(Larval Length)
3 mm (11-14 mm length)
3 mm (>= 15 mm length)
3 mm (<= 4 mm length)
3 mm (5-6 mm length)
3 mm (7-8 mm length)
3 mm (>=9 mm length)
2 mm, 0.095 m/s (<= 4 mm length)
2 mm, 0.095 m/s (5-7 mm length)
2 mm, 0.095 m/s (8-10 mm length)
2 mm, 0.095 m/s (11-14 mm length)
2 mm, 0.095 m/s (>= 15 mm length)
2 mm, 0.095 m/s (<= 4 mm length)
2 mm, 0.095 m/s (5-6 mm length)
2 mm, 0.095 m/s (7-8 mm length)
2 mm, 0.095 m/s (>=9 mm length)
2 mm, 0.19 m/s (<= 4 mm length)
2 mm, 0.19 m/s (5-7 mm length)
2mm, 0.19 m/s (8-10 mm length)
2mm, 0.19 m/s (11-14 mm length)
2mm, 0.1 9 m/s (>= 15mm length)
2 mm, 0.19 m/s (<= 4 mm length)
2 mm, 0.19 m/s (5-6 mm length)
2 mm, 0.19 m/s (7-8 mm length)
2 mm, 0.19 m/s (>=9 mm length)
2 mm, 0.4 m/s (<= 4 mm length)
2 mm, 0.4 m/s (5-7 mm length)
2 mm, 0.4 m/s (8-10 mm length)
2 mm, 0.4 m/s (11-14 mm length)
2 mm, 0.4 m/s (>= 15 mm length)
2 mm, 0.4 m/s (<= 4 mm length)
2 mm, 0.4 m/s (5-6 mm length)
2 mm, 0.4 m/s (7-8 mm length)
2 mm, 0.4 m/s (>=9 mm length)
0.5 mm; 0.15m/sec
0.5mm; 0.15m/sec
0.5 mm; 0.15m/sec
0.5 mm; 0.15 m/sec
0.5 mm; 0.15 m/sec
0.5 mm; 0.1 5 m/sec
0.5 mm; 0.15 m/sec
Species Name
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Bay Anchovy
Naked Goby
Naked Goby
Naked Goby
Naked Goby
All fish
Bay Anchovy
Bay Anchovy
Naked Goby
Northern pipefish
Skilletfish
Striped Blenny
Life Stage
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Density
Units
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/1000m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
Density
Behind
Technology
0.3
0.5
557.1
87.6
11.2
7.8
23.7
15.7
1.9
0
0.3
400.5
58.4
6.6
4.7
32.3
16.3
3.3
0.3
0.8
424.8
109.4
7.7
3.6
8.8
13
3.3
0.5
0.8
598.6
119.2
27.1
11.4
41.7
134.1
2.3
20.0
0.4
0.5
0.3
Density in
Front of
Technology
1.3
3.3
535.7
148.7
49.7
49.1
9.6
20.1
7.7
1.3
3.3
535.7
148.7
49.7
49.1
9.6
20.1
7.7
1.3
3.3
535.7
148.7
49.7
49.1
9.6
20.1
7.7
1.3
3.3
535.7
148.7
49.7
49.1
146.6
998.8
15.0
98.2
2.3
2.5
1.9
Percent
Reduction
76.92
84.85
-3.99
41.09
77.46
84.11
-146.88
21.89
75.32
100.00
90.91
25.24
60.73
86.72
90.43
-236.46
18.91
57.14
76.92
75.76
20.70
26.43
84.51
92.67
8.33
35.32
57.14
76.92
75.76
-11.74
19.84
45.47
76.78
71.56
86.57
84.67
79.63
82.61
80.00
84.21
m
x
'
-o
3
C7
C7
o
-o
-o
TO
3
Q.
x'
-------
n
Exhibit 11C-2. (Continued)
Study
ID
201
201
201
201
201
201
201
202
202
202
202
202
202
202
203
203
203
203
203
203
203
211
211
212
212
196
196
196
196
196
197
197
197
197
197
198
198
198
198
199
199
199
Year
Facility Name or
Location
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Chesapeake Bay
Oyster Creek)
Oyster Creek)
Oyster Creek)
Oyster Creek)
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Portage River
Techno-
logy
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
Screen Mesh Size, Slot Velocity
(Larval Length)
0.5 mm; 0.30 m/sec
0.5mm; 0.30 m/sec
0.5mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5mm; 0.30 m/sec
0.5mm; 0.30 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.1 5 m/sec
1.0 mm; 0.1 5 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.1 5 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0 mm
1.0 mm
2.0mm
2.0mm
0.5 mm; 0.15 m/sec
0.5 mm; 0.15 m/sec
0.5 mm; 0.1 5 m/sec
0.5 mm; 0.1 5 m/sec
0.5 mm; 0.1 5 m/sec
0.5mm; 0.30 m/sec
0.5mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.1 5 m/sec
1.0 mm; 0.1 5 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
Species Name
All fish
Bay Anchovy
Bay Anchovy
Naked Goby
Northern pipefish
Skilletfish
Striped Blenny
All fish
Bay Anchovy
Bay Anchovy
Naked Goby
Northern pipefish
Skilletfish
Striped Blenny
All fish
Bay Anchovy
Bay Anchovy
Naked Goby
Northern pipefish
Skilletfish
Striped Blenny
Opossum Shrimp
Opossum Shrimp
Opossum Shrimp
Opossum Shrimp
All fish
Bass
Carp
Freshwater Drum
Shad
All fish
Bass
Carp
Freshwater Drum
Shad
All fish
Bass
Carp
Shad
All fish
Bass
Carp
Life Stage
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Density
Units
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/m3
#/m3
#/m3
#/m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
Density
Behind
Technology
36.8
406.2
1.1
19.3
0.5
0.8
0.9
45.7
682.3
4.7
16.9
0.4
0.7
0.9
49.9
356.9
1.6
33.0
0.5
1.4
1.0
8.9
16.2
22.4
26.6
1.1
0.5
2.7
0.1
116.9
2.8
0.2
1.1
0.6
123.3
4.5
0.0
2.1
511.1
97.1
0.0
2.7
Density in
Front of
Technology
87.6
503.1
8.1
54.6
2.5
1.6
2.3
71.0
774.0
6.0
35.3
1.2
1.9
1.6
106.3
271.7
3.5
74.3
1.1
2.4
1.9
19.3
20.0
19.3
20.0
45.1
1.6
2.2
2.5
148.2
42.0
0.7
1.5
14.2
244.4
102.9
0.4
1.3
614.9
117.2
0.4
6.0
Percent
Reduction
57.99
19.26
86.42
64.65
80.00
50.00
60.87
35.63
11.85
21.67
52.12
66.67
63.16
43.75
53.06
-31.36
54.29
55.59
54.55
41.67
47.37
53.89
19.00
-16.06
-33.00
97.56
68.75
-22.73
96.00
21.12
93.33
71.43
26.67
95.77
49.55
95.63
100.00
-61.54
16.88
17.15
100.00
55.00
cm
U)
TO
Q-
70
C7
C7
-------
Exhibit 11C-2. (Continued)
Study
ID
199
199
192
192
192
192
192
193
193
193
193
193
194
194
194
194
194
195
195
195
195
195
213
213
213
213
213
213
213
214
214
214
214
214
214
214
214
191
191
191
191
Year
Facility Name or
Location
Portage River
Portage River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
Sakkonet River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
St. John's River
Big Bend
Big Bend
Big Bend
Big Bend
Techno-
logy
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
CW-F
TS-F
TS-F
TS-F
TS-F
Screen Mesh Size, Slot Velocity
(Larval Length)
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
0.5 mm; 0.15 m/sec
0.5 mm; 0.1 5 m/sec
0.5 mm; 0.1 5 m/sec
0.5mm; 0.15 m/sec
0.5 mm; 0.15 m/sec
0.5mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5 mm; 0.30 m/sec
0.5mm; 0.30 m/sec
0.5mm; 0.30 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.1 5 m/sec
1.0 mm; 0.1 5 m/sec
1.0 mm; 0.15 m/sec
1.0 mm; 0.15 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0mm; 0.30 m/sec
1.0 mm
1.0 mm
1.0 mm
1.0 mm
1.0 mm
1.0 mm
1.0mm
2.0mm
2.0mm
2.0mm
2.0mm
2.0mm
2.0mm
2.0mm
2.0mm
Species Name
Freshwater Drum
Shad
All fish
All fish
Grubby
Sand Lance
Winter flounder
All fish
All fish
Grubby
Sand Lance
Winter flounder
All fish
All fish
Grubby
Sand Lance
Winter flounder
All fish
All fish
Grubby
Sand Lance
Winter flounder
All fish
Gobiosoma bosci
Lepomis spp.
Lucania parva
Menidia beryllina
Microgobius gulosus
Unidentified
All fish
Gobiosoma bosci
Lepomis spp.
Lucania parva
Menidia beryllina
Microgobius gulosus
Strongylura marina
Unidentified
Anchoa mitchilli
Anchoa mitchilli
Bardiella chrysura
Blenniidae
Life Stage
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Larvae
Eggs
Larvae
Larvae
Larvae
Density
Units
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#
#/100m3
#/100m3
#/100m3
#/100m3
Density
Behind
Technology
2.8
530.9
1.1
14.5
0.4
3.2
11.3
0.0
14.5
0.8
4.9
9.8
30.6
42.2
6.0
15.5
21.7
39.6
35.7
3.7
18.6
12.1
13152507.0
5783474.0
71462.0
36461.0
1762408.0
530668.0
4534611.0
14530529.0
5660498.0
63975.0
11539.0
1748200.0
1778814.0
1915.0
5008284.0
1071.0
26.8
0.0
5.3
Density in
Front of
Technology
9.9
571.3
14.5
81.1
13.7
47.5
25.7
22.8
52.6
10.4
24.9
17.4
42.0
43.5
10.8
12.8
20.4
42.9
43.3
7.3
19.0
14.5
38692597.0
13318458.0
460793.0
33517.0
2345561.0
14240799.0
7975672.0
38692597.0
13318458.0
460793.0
33517.0
2345561.0
14240799.0
10582.0
7975672.0
12860.0
239.6
2.0
29.7
Percent
Reduction
71.72
7.07
92.41
82.12
97.08
93.26
56.03
100.00
72.43
92.31
80.32
43.68
27.14
2.99
44.44
-21.09
-6.37
7.69
17.55
49.32
2.11
16.55
66.01
56.58
84.49
-8.78
24.86
96.27
43.14
62.45
57.50
86.12
65.57
25.47
87.51
81.90
37.21
91.67
88.81
100.00
82.15
m
x
'
-o
3
Q_
TO
C7
C7
-o
-o
TO
3
Q.
x'
-------
n
Exhibit 11C-2. (Continued)
Study
ID
191
191
191
191
191
191
Year
Facility Name or
Location
Big Bend
Big Bend
Big Bend
Big Bend
Big Bend
Big Bend
Techno-
logy
TS-F
TS-F
TS-F
TS-F
TS-F
TS-F
Screen Mesh Size, Slot Velocity
(Larval Length)
Species Name
Cynoscion
nebulosus
Gobiesox strumosus
Gobiidae
Menippe mercenaria
Penaeus
Sciaenidae
Life Stage
Larvae
Larvae
Larvae
Zoea
(unstaged)
Juvenile
Eggs
Density
Units
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
#/100m3
Density
Behind
Technology
0.0
1.1
7.6
0.3
0.0
1062.0
Density in
Front of
Technology
1.1
8.9
30.3
24.6
1.9
38595.0
Percent
Reduction
100.00
87.64
74.92
98.78
100.00
97.25
Technology codes: TS-F=Fine-mesh traveling screens; CW-F=fine-mesh wedgewire screens
cm
U)
TO
Q.
70
C7
C7
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix D
Appendix D to Chapter 11: Statistical Procedures for
Estimating the Mean and 95th Percentile of Impingement
Mortality Percentages
11D.O Introduction
This appendix describes the beta distribution model used to develop the proposed
impingement mortality limitations described in Chapter 11. It also describes alternative
statistical methods that EPA considered in developing the proposed limitations. For the
final rule, EPA intends to reevaluate its selection of the beta distribution for impingement
mortality percentage data.
11D.1 The Beta Distribution
This section presents an overview of the beta distribution and its application to the
impingement mortality percentages used as a basis for the proposed limitations. Section
1 ID. 1.1 presents an overview of the beta distribution. Section 1 ID. 1.2 describes the
estimation procedures for its parameters. Section 1 ID. 1.3 derives the mean and 95th
percentile using the parameters. Section 1 ID. 1.4 provides an example of the calculations
using impingement mortality percentage data.
11 D.1.1 Overview of the Beta Distribution
The beta distribution assigns positive probability to numbers between 0 and 1 (or,
equivalently, percentages between 0 percent and 100 percent). Therefore, this
distribution is used frequently to model proportions (Casella and Berger, 2002).
Unlike the symmetric and bell-shaped form of the normal distribution, the beta
distribution does not have a single characteristic form in all situations. A beta
distribution can hold a variety of shapes depending on the values of its two parameters, a
and ft (which both must be positive). This makes the beta distribution very flexible to
apply to a specific scenario.
The following exhibits provide some examples of the beta distribution for different
values of a and ft.
• If the two parameters are equal to each other, then the beta distribution is
symmetric about 0.5 and the mean is equal to 0.5. In the case where a and ft both
equal 1 as shown in Exhibit 1, the beta distribution is equivalent to the uniform
distribution over the range (0, 1). The distribution is U-shaped if the common
value is less than 1. Exhibit 2 shows this pattern for a and ft both equal to 0.5.
HD-l
-------
Chapter 11: Appendix D
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11D-1. Shape of the beta distribution when a = 1 and 0 = 1
0.0 0.2 0.4 0.6 0.8 1.0
Exhibit 11D-2. Shape of the beta distribution when a = 0.5 and/?= 0.5
a. = 0.5, R = 0.5
0.0 0.2 0.4 0.6 0.8 1.0
• If a and ft have the same value and the value is greater than 2, the beta distribution
resembles a symmetric bell-shaped curve. Exhibit 11D-3 shows this shape for a
and ft both equal to 5.
11D-2
-------
§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix D
Exhibit 11D-3. Shape of the beta distribution when a = 5 and /? = 5
a. = 5, R = 5
0.0
0.2
0.4
0.6
0.8
1.0
The distribution is unimodal (i.e., has a single peak) if both a and ft are greater
than 1. The beta distribution is skewed left when a is greater than ft (see Exhibit
11D-4), and skewed right when a is less than ft. If a and ft are unequal but only
one parameter exceeds 1, then the distribution is constantly decreasing if ft
exceeds 1 (see Exhibit 11D-5), and is constantly increasing if a exceeds 1.
11D-3
-------
Chapter 11: Appendix D
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11D-4. Shape of the beta distribution when a = 5 and 0 = 2
a. = 5, B = 2
0.0 0.2 0.4 0.6 0.8 1.0
Exhibit 11D-5. Shape of the beta distribution when a = 1 and ft = 5
0.0 0.2 0.4 0.6 0.8 1.0
11D-4
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix D
If Xis a random variable with a beta distribution, then the cumulative probability
distribution function of X(i.e., the probability that Xcan hold values less than or equal to
some specified value x) takes the following form:
i
- tf~ldt,
Jo ""
where F(c) denotes the gamma function, defined as
f'QO
T(c) = / zc-le-*dz.
Jo
If c is an integer, then
r(c) = (c-i)i
= (c- 1) x (c-2) x (c-3) x ... x 2 x 1.
If c is not an integer, then F(c) must be approximated using a computer. The expected
value and variance of X can be expressed in terms of its parameters a and/? as follows:
E(X] =
Var(X] =
/3
a8
1 1 D.1 .2 Parameter Estimation for the Beta Distribution
EPA estimated a and ft using a procedure called method of moments (MOM) estimation
that can be used for parameter estimation for beta and other distributions. While it also is
possible to estimate the parameters for the beta distribution using maximum likelihood
estimation (MLE), the MLE approach requires iterative computer algorithms to solve
equations that are documented in references such as Johnson and Kotz (1970). In
estimating the proposed limitations, EPA selected the MOM estimation procedure
because it is simpler and the values can be directly estimated from a series of equations.
The following describes the estimation procedure.
For a set of n independent observations {xlt ...,xn] originating from a common
distribution, the Jf sample moment is defined as:
mk = -
n
i=l
The first sample moment, m\, equals the simple average of the n observations. The A*
population moment of the random variable X equals E(XC ). Therefore, the first population
moment equals the expected value, or mean, of X (i.e., E(Xj). The second population
moment equals the variance of X plus the square of the mean of X. Thus, if X has a beta
distribution, the first and second population moments are given by the following
expressions:
HD-5
-------
Chapter 11: Appendix D § 316(b) Existing Facilities Proposed Rule -TDD
E(X) =
/3
The MOM estimators are found by setting the first k sample moments equal to the first k
population moments, where k is typically equal to the number of parameters being
estimated. Thus, for the beta distribution, which has two parameters to estimate, the
MOM estimators are found by setting the first sample moment equal to the first
population moment and the second sample moment equal to the second population
moment, and then solving for the parameters in terms of the observations.
If the n independent observations {xj, ..., xn] originate from a beta distribution, then
setting the sample mean (the first sample moment) equal to the expected value results in
the following equation:
-, n
-$> = E(X)
1=1
a
a + p (11D.1)
Setting the second sample moment equal to the second population moment results in the
following equation:
a/3 , / a
a + /3 ,
(11D.2)
We then solve Equation (1 ID. 1) and Equation (1 ID. 2) simultaneously for a and ft to
obtain the estimators a and /3. This produces the following result:
=
e =
where X is the simple average of the n observations and V equals the following quantity:
Note that Fis similar to the common formula for the sample variance except that the
denominator equals n instead of (n - 1).
HD-6
-------
§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix D
11 D.1.3 Estimation of the Mean and 95th Percentile Under the Beta
Distribution
If Xrepresents percent impingement mortality, then we are assuming that Xhas a beta
distribution with parameters a and ft. Once Equation (A.3) is applied to reported values
of percent impingement mortality data to estimate a and/?, these estimates are then used
to estimate the mean and 95* percentile of the distribution. We do not assume a specific
form of the beta distribution. The observed data will specify the shape through the
estimates of a and ft.
The mean of the distribution is estimated by the following:
E(X) =
a
8
where a and /? denote the MOM estimates of a and ft, respectively (Equation 1 ID.3).
However, no simple expressions exist for estimating the 95th percentile using these
estimates of a and ft. Johnson and Kotz (1970) provide some approximations for
percentiles of the beta distribution. Many statistical software packages, including R and
SAS, have procedures for estimating the 95th percentile of a beta distribution. In R, the
following command returns an approximation of the 95th percentile:
The following command can be used to approximate the 95* percentile of the beta
distribution in SAS or Excel:
betainv(0.95, a,ft).
11D.1.4 Example: Applying the Beta Distribution Model to
Impingement Data
This section provides an example on estimating the expected value and 95th percentile
under the beta distribution. This example considers the set of impingement mortality data
which EPA used to derive the monthly average limitation on impingement mortality.
Also presented in Exhibit 11-4, these data are listed in Exhibit 11D-6. The average Xof
the percent impingement mortality column equals 12.56 percent, or 0.1256. The value of
F(the mean squared difference between the individual values and the overall average)
equals 0.78 percent, or 0.0078. Thus, the MOM estimate of a is:
a = 0.1256
= 1.64.
HD-7
-------
Chapter 11: Appendix D
§ 316(b) Existing Facilities Proposed Rule -TDD
The MOM estimate of is:
(3 = (1-0.1256)
= 11.44.
'0.1256(1-0.1256)
0.0078
- 1
Since we estimate both a and ft to be greater than 1 and a to be less than /?, our estimated
beta distribution is unimodal and skewed right (i.e., the highest probabilities are
associated with data below 0.5, or 50 percent impingement mortality).
We estimate the mean of the distribution to be the following:
E(X) =
/3
1.64
1.64 + 11.44
= 0.125
= 12.5%.
which EPA rounded to 12 for the proposed annual average limitation.
We estimate the 95 percentile using built-in functions of readily available software. For
example, if we run the R function
qbeta(0.95, 1.64, 11.44),
we obtain a value of 0.298, or 29.8 percent. The Excel function betainv(0. 95, 1.64,1 1.44)
also returns a value of 0.298. Thus, we estimate the 95th percentile of the population to
be 29.8 percent (which EPA rounded to 30 percent for the proposed monthly average
limitation).
Exhibit 11D-6. Impingement Mortality Data Used to Calculate Mean and 95
Percentile of the Beta Distribution in This Example
th
Facility
Name
Arthur Kill
Dunkirk
Huntley
Sampling Period
Unit 20, 1994-1995
Unit 30, 1994-1995
12/20/98 to 01 709/99
04/20/99 to 04/28/99
08/1 6/99 to 09/04/99
11/02/99 to 11/1 1/99
01/2 1/99 to 01/25/99
10/24/99 to 10/29/99
Total Number of
Impinged Fish
7,130
3,408
6,775
3,562
1,220
8,928
6,120
3,258
Total Number of
Impinged Fish
that Died
1,366
235
261
435
182
243
561
1,025
Percent
Impingement
Mortality
19.2
6.9
3.9
12.2
14.9
2.7
9.2
31.5
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix D
11D.2 Alternatives to the Beta Distribution
In addition to the beta distribution model, EPA identified other alternative statistical
models that might be appropriate for developing limitations related to impingement
mortality data. Although EPA determined that the beta distribution was appropriate in
developing the proposed limitations, it intends to reevaluate whether other statistical
methods or data types might be more appropriate for the final rule. The following
sections describe six alternatives. The first four model the same type of data used for the
proposed limitations (i.e., impingement mortality percentages). These four alternatives
are: a normal distribution model, methods which focus on estimating upper percentiles of
a distribution, survival analysis, and a nonparametric approach. The last two alternatives
model different data types: the number offish killed and Age-1 Equivalents.
11 D.2.1 Normal Distribution Model
One alternative approach is based on the normal distribution, which has many well-
known properties and is the basic assumption for many statistical methods. While
normally distributed data can hold any positive or negative value, percent impingement
mortality can range only from 0 to 100. Thus, in this approach, the logit function would
be applied to the percentages (expressed as proportions). The logit function is defined as
the natural logarithm of the odds of impingement mortality. Statisticians have often used
this approach to transform proportions into values that satisfy the assumptions of the
normal distribution. Ifp is impingement mortality expressed as a proportion between 0
and 1 (e.g., 20 percent mortality becomes a proportion of 0.2), then the logit ofp is equal
to the following:
/ P
logit (p) = log
l-p
To estimate the expected value of the distribution, the arithmetic mean (X) of the logit-
transformed proportion data (e.g., data from Exhibit 11D-5) is calculated. This mean is
then transformed back to the proportion scale by using the following inverse logit
function, which yields an estimated expected value for the proportion of impingement
mortality:
= exp(X)
1 + exp(X)
The 95th percentile is estimated by first calculating the following:
SO. 95
= X + 1.6455.
where S is the standard deviation of the logit-transformed proportion data. The value zo.95
is then transformed back to the proportion scale by applying the inverse logit function,
yielding the estimated 95* percentile for the proportion of impingement mortality. The
expected value and 95th percentile for proportions are converted to percentages by
multiplying by 100.
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Chapter 11: Appendix D § 316(b) Existing Facilities Proposed Rule -TDD
For data reported as proportions (or percentages), the beta distribution model is more
flexible than the logit model based on the normal distribution. When applying the beta
distribution, the data are used to estimate a and ft directly, so the shape of the beta
distribution reflects the data collected. In contrast, the shape of the underlying
distribution of the percentages under the normal distribution model is influenced by the
choice of the logit function and the assumption that the transformed data are normally
distributed. Also, transformation bias that may be introduced under the normal
distribution model is not encountered with the beta distribution model. Thus, for these
reasons, EPA selected the beta distribution model over the normal distribution model to
develop the proposed limitations.
11 D.2.2 Methods for Estimating Upper Percentiles
While the beta distribution approach appears to perform well in characterizing the overall
distribution of percent impingement mortality, EPA may evaluate statistical methods that
focus on characterizing the upper tail of a distribution of percentages. One possible
approach would be to truncate data within the lower tail of the distribution, so that data
important to characterizing the upper tail of the distribution have greater weight. Such an
approach also reduces the impact that the choice of distribution model has on the estimate
of the 95* percentile. However, these methods would not be used to estimate other
distributional parameters such as the expected value. In its evaluation, EPA would
determine if methods such as these can lead to a more accurate estimate of the 95th
percentile of the distribution of percent impingement mortality.
11D.2.3 Survival Analysis
For the final rule, EPA may consider survival analysis procedures. This approach would
require mortality data that were measured at different times following impingement. The
data used as the basis for the proposed limitation all reported mortality at 24 hours, and
thus, the data were not suitable for a survival analysis approach. However, for the final
rule, it is possible that EPA will select a different set of data that may measure mortality
at different time points. If several studies considered a variety of different time points at
which it monitored impingement-related deaths, it may be possible to model
impingement mortality data using survival analysis techniques such as a Kaplan-Meier or
probit-type approach. This may result in an alternative estimate for the expected
impingement mortality (or survival) that occurs at a given point in time, which may be
appropriate for characterizing an achievable long-term performance among the facilities.
11D.2.4 Nonparametric Procedures
Nonparametric procedures exist for estimating the average and 95th percentile.
Nonparametric procedures use the ordered data values to approximate percentiles. The
95th percentile would be estimated by the observed value below which fall the values of
95 percent of the observations. A nonparametric approach is sometimes appropriate
because it does not place assumptions on the type of underlying distribution. However,
this method is not very precise for small sample sizes. For this reason, EPA determined
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§ 316(b) Existing Facilities Proposed Rule -TDD
Chapter 11: Appendix D
that it was not appropriate to take a nonparametric approach with the data that were used
as the basis of the proposed limitations. For example, with a data set containing ten
observations, the same observation (the one with the largest value) would be used to
approximate the 91st percentile, the 95th percentile, and the 99th percentile.
11 D.2.5 Modeling Number of Fish Instead of Percentages
For the proposed limitations, EPA used the number offish killed in its calculations of the
impingement mortality percentages. EPA then used the percentages as the basis for the
proposed limitations. These percentages allow for flexibility in the number offish in
different water bodies and seasons. In other words, more fish impinged, the larger the
number that can be killed.
In the preamble to the proposed rule, EPA has requested comment on an alternative for
sites where few fish are likely to be impinged. For this alternative approach, EPA
calculated a daily average number offish that were killed during each sampling period as
follows:
daily average =
total number of impinged fish that died
number of nights in sampling event
Exhibit 11D-7 shows the results of these calculations. (EPA did not include Arthur Kill
data because the number of nights in each sampling event was not available.) For the
final rule, if EPA were to consider number offish killed as an alternative, it might
statistically model the data or select the minimum observed value. This minimum value
of 23 fish mortalities per day is derived from the Dunkirk study during the summer
sampling event.
Exhibit 11D-7. Number of Fish Killed: Daily Averages During Sampling Events
Facility
Name
Dunkirk
Huntley
Sampling Period
12/20/98 to 01 709/99
04/20/99 to 04/28/99
08/1 6/99 to 09/04/99
11/02/99 to 11/11/99
01/2 1/99 to 01/25/99
10/24/99 to 10/29/99
Number of
Nights
8
8
8
8
5
5
Total Number
of Impinged
Fish
6,775
3,562
1,220
8,928
6,120
3,258
Total Number
of Impinged
Fish that Died
261
435
182
243
561
1,025
Arithmetic
Average of
Dead Fish Per
Night of
Sampling
32.6
54.4
22.8
30.4
112.2
205.0
11D.2.6 Modeling Age-1 Equivalents
Instead of modeling percentages, EPA considered use of age-1 equivalent (A1E) data in
developing the proposed limitations. A1E is a metric based on the Equivalent Adult
Model (EAM), which has been used by the EPA in their assessment of environmental
benefits. The EAM is a method for expressing losses of organisms killed at various ages
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Chapter 11: Appendix D § 316(b) Existing Facilities Proposed Rule -TDD
as if the losses had all occurred at the same age, known as the age of equivalency
(Goodyear, 1978). Converting impingement and entrainment losses to the same age
provides a common measure of loss that is directly comparable among species, years,
facilities, or the regions where mortality occurs. The age of equivalency can be any age
of interest. To support section 316(b) benefits analyses, EPA converted impingement and
entrainment losses to age-1 equivalents.
Age-1 equivalents are calculated as the product of the age-specific numbers of organisms
impinged and entrained, and the age-specific cumulative survival rates of these organisms
from the age of loss to age 1. For example, if the cumulative survival rate between the
larval stage of a fish species and age 1 is 3 percent, then 100 larval losses would be
expressed as 3 A1E. A comprehensive description of the calculations involved in the
EAM is provided in Chapter Al of the Regional Benefits Analysis for Phase III of EPA's
Section 316(b) rulemaking (EPA, 2006).
For the benefits assessment for this proposed rulemaking, EPA used life history data for a
significant amount of the specific species which the EPA has loss records for at 316(b)
facilities. However, this list of species life history data is incomplete and particularly for
impingement records lacks specific ages offish which are observed to be impinged. In
addition, EPA recognizes that as live organisms increase in age they are less likely to be
impinged at most Phase II facilities.
After evaluating the practicality of developing comprehensive age-1 conversion factors
for all species and their life stages in different water bodies, EPA concluded that such an
approach was not practical for two main reasons. First, the expertise, data, and time
required to accurately calculate specific life history data for all organisms at all facilities
were not possible without significant assumptions and uncertainty. Second, EPA
recognized the increased burden which would be placed upon facilities, which would
have to accurately identify individual species and their specific age, before calculating
the A1E. As such, the EPA determined that simply counting individual organisms that
are impinged has significantly less uncertainty than calculating A1E and is less
burdensome to the states and facilities implementing an impingement limit.
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix D
11D.3 References
Casella, George and Berger, Roger L. 2002. Statistical Inference, 2n Edition. Pacific
Grove, CA: Duxbury.
Goodyear, C.P. 1978. Entrainment Impact Estimates Using the Equivalent Adult
Approach. FWS/OBS - 78/65. U.S. Department of the Interior, Fish & Wildlife
Service, Washington, DC. July.
Johnson, Norman L. and Kotz, Samuel. 1970. Continuous Univariate Distributions - 2.
New York: Wiley.
U.S. Environmental Protection Agency (EPA). 2006. Regional Analysis for the Final
Section 316(b) Phase III Existing Facilities Rule. EPA-821-R-06-002. June 2006.
Retrieved from http://www.epa.gov/waterscience/316b/phase3/index.html,
December 2008.
1 ID-IS
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix E
Appendix E to Chapter 11: Analysis of Variance on
Percent Reduction in Entrained Organisms
11E.O Introduction
This appendix describes an analysis of variance (ANOVA) applied to data collected from
several studies (and at several different facilities) that measured entrainment of organisms
through fine mesh screens placed on the intakes to cooling water intake structures. The
objective of the ANOVA was to evaluate whether screen slot width and/or slot velocity
have a statistically significant impact on the percent reduction of organisms entrained
through the screens. Section 11.3 of Chapter 11 identifies the entrainment data that were
used in the analyses presented in this appendix.
The following sections provide a general overview of ANOVA, the questions addressed
in the ANOVA of the entrainment data, the data selected for the ANOVA, and the
models and results used to evaluate each question. The appendix also describes potential
refinements that EPA may consider for the final rule.
11E. 1 General Overview of ANOVA
ANOVA techniques are appropriate for data sets that contain the measure of interest
(known as the "dependent variable") and a series of "predictor" (or "independent")
variables. In the analysis, the ANOVA expresses the value of the dependent variable as a
mathematical function of the predictor variables, known as the ANOVA model. A general
class of models is specified upfront, and then the "best" model in this class is determined
by applying statistical techniques (i.e., "fitting the model") to the available data. As the
ANOVA model is fitted to the data, statistical hypothesis tests are performed to
determine whether different values of one or more predictor variables significantly affect
the value of the dependent variable.
For the outcome of the ANOVA approach applied in this appendix to be statistically
valid, the values of dependent variable, after accounting for any effects due to the
predictor variables included in the model, must satisfy certain conditions. In particular,
the data values must be independent from one another and originate from a common
normal (bell-shaped) distribution.
One useful outcome of the ANOVA is a set of least-squares means for the dependent
variable which can be reported at each value of one or more predictor variables. Named
for the statistical technique used to fit the ANOVA model to the data, least-squares
means represent what the ANOVA model predicts for the average value of the dependent
variable at the specified value(s) of the predictor variable(s). By reviewing these least-
squares means (as well as confidence intervals placed on these means, which can also be
output from the ANOVA), one can identify where differences are present in the
dependent variable among values of the predictor variables.
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Chapter 11: Appendix E § 316(b) Existing Facilities Proposed Rule -TDD
11E.2 Questions to Address in Entrainment ANOVA
In the entrainment analysis, percent reduction in entrained organisms serves as the
dependent variable, and slot width and slot velocity serve as predictor variables. The
statistical hypothesis tests within the ANOVA answer the following questions:
1. When both slot width and slot velocity are considered jointly, do differences in
the values of either (or both) variables lead to statistically significant differences
in the percent reduction in entrained organisms?
2. If only slot width is considered, do differences in the slot width lead to
statistically significant differences in the percent reduction in entrained
organisms? (EPA formulated question #2 in part because not all facilities
provided information on slot velocity when reporting percent reduction in
entrainment.)
If the answer to either question is "no," then one can conclude that any observed
differences in percent reduction of entrained organisms among different slot widths
and/or slot velocities are the result of other unaccounted factors, or perhaps simply due to
chance.
EPA used the generalized linear models (GLM) procedure in the SAS System to
perform the ANOVAs. The ANOVA models selected for the GLM procedures differed
slightly to address questions #1 and #2. Sections 11E.4 and 11E.5 describe the models.
11E.3 Data Used for the Entrainment ANOVA
In assessing the effects of slot width and slot velocity on percent reduction in entrained
organisms, EPA applied an ANOVA separately to three sets of percent reduction data,
with the three data sets distinguished by the life stage of the organisms:
1. Entrainment data for eggs only
2. Entrainment data for larvae only (EPA considered "larvae" to be any entrainable
life stage other than eggs.)
3. Entrainment data for all organisms (i.e., all life stages).
The percent reduction data which EPA used in each execution of the ANOVA appear in
the last columns of Exhibits 11-7, 11-13, and 11-16 in Chapter 11. For question 1, the
analysis did not include percent reduction data from the Big Bend study, the Brunswick
study, and the 1982 Chalk Point study because references on these studies did not report
slot velocity.
EPA used graphical techniques to evaluate the extent that the entrainment data values met
the conditions of independence and normality described in Section 11E.1. In some cases
(as noted below), EPA found that if the natural logarithm of the percent reduction values
were taken, the resulting log-transformed values satisfied the ANOVA requirements
better than the percent reduction values themselves. In these cases, EPA applied the
ANOVA to log-transformed percent reduction data values. However, because logarithms
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix E
can be taken only of positive data values, percent reduction data values of less than zero
were excluded from the analyses of log-transformed data.
11E.4 Model and Results for Question #1 (effects of slot width
and slot velocity on log-transformed percent)
The ANOVA model to address question #1 took the following form:
-pVj + eyk (1)
where Yyk is the percent reduction in entrainment associated with the &th study that
utilized the /h slot width and/h slot velocity, // is an overall constant, at is an additional
constant amount that is associated with the /* slot width, /?is a slope factor, Vj is the/11
slot velocity, and e^ is random error left unexplained by the model. Thus, this model
expressed the log-transformed percent reduction in entrained organisms (i.e., the
dependent variable) as equal to a constant value (// +«;•) which could differ for different
slot widths. Then, working from this constant value, the model allowed the log-
transformed percentage to vary in a linear fashion based on the value of the slot velocity.
For each slot width, the model allowed each increase of 1.0 m/s in slot velocity to result
in a constant change (represented by ft) in the value of the log-transformed percentage.
(Preliminary investigation concluded that no statistical evidence existed that the size of
the change /? needed to vary for different slot widths.)
By fitting this model to the percent reduction data and applying statistical hypothesis
tests, EPA answered question #1 by doing the following:
• To determine whether slot width led to statistically significant differences in the
(log-transformed) percent reduction data (while also accounting for slot velocity),
EPA performed the following statistical hypothesis test:
o Null hypothesis: the values at were each equal to zero (i.e., for each slot
width).
o Alternative hypothesis: at least one value at was nonzero.
• To determine whether slot velocity led to statistically significant differences in the
(log-transformed) percent reduction data (while also accounting for slot width),
EPA performed the following statistical hypothesis test:
o Null hypothesis: the value /?was equal to zero.
o Alternative hypothesis: the value /? was unequal to zero.
In both cases, if the significance level (i.e.,/?- value) of the test was less than 0.05, then
EPA concluded that the data were sufficient for rejecting the null hypothesis in favor of
the alternative hypothesis.
EPA fitted the ANOVA model in Equation (1) separately to the (log-transformed) percent
reduction data for eggs only, larvae only, and total organisms (as given in Tables 11-13,
11-16, and 11-7, respectively). The results of the statistical hypothesis tests performed
within the ANOVA were as follows:
11E-3
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Chapter 11: Appendix E
§ 316(b) Existing Facilities Proposed Rule -TDD
• The effect of slot width on percent reduction in entrained organisms was not
statistically significant for either total organisms (p-value = 0.055), eggs (p-value
= 0.053), or larvae (p-value = 0.169). Note, however, that the/>-value was just
barely above 0.05 in the tests involving data on either total organisms or eggs.
This implies that while some differences in percent reduction may be present that
could be attributable to different slot widths, the size of the differences among slot
widths was not sufficient to conclude significance at the 0.05 level in either case,
or variability in the slot width data was high enough to prevent observed
differences from being statistically significant at the 0.05 level1.
• Like slot width, the effect of slot velocity on percent reduction was not
statistically significant for either total organisms (p-value = 0.183), eggs (p-value
= 0.154), or larvae (p-value = 0.874).
Exhibit 11E-1 lists the least squares means for percent reduction in entrained organisms
that were associated with the fitted ANOVA model at each encountered slot width, along
with 95 percent confidence intervals. (These least squares means and confidence
intervals have been transformed from log-units to percentage units.) While the statistical
hypothesis tests involving the slot width effect did not yield statistically significant
results at the 0.05 level in any instance, this table shows some interesting patterns in the
least squares means. In particular, for each set of data, the largest predicted average
percent reduction occurred at a slot width of 0.5 mm. Furthermore, the largest
differences among the least squares means (and the least amount of overlap in their
confidence intervals) occurred between the 0.5 mm and 1.0 mm mesh sizes.
Exhibit 11E-1. Least Squares Means for Percent Reduction in Entrainment and 95
Percent
Confidence Intervals, for Each Encountered Slot Width, Under the ANOVA Model Addressing Question #1
Data Set
Total Organisms
Eggs Only
Larvae Only
Slot Width (mm)
0.5
1.0
2.0
3.0
0.5
1.0
3.0
0.5
1.0
2.0
3.0
Least Squares
Mean (%)
59.7
23.8
48.6
24.1
75.0
20.3
25.0
55.6
24.0
48.6
16.1
95% Confidence Interval on
Least Squares Mean
(34.8, 102.5)
(15.3, 36.9)
(27.1, 87.2)
(6.5, 89.0)
(37.1, 151.9)
(9.4, 43.9)
(4.5, 140.5)
(27.4, 113.1)
(13.9,41.5)
(22.5, 105.0)
(2.9, 90.0)
1 The significance level denotes the maximum observed p-value that will lead to rejecting the hypothesis
that slot width has no significant effect on percent reduction, for the alternative hypothesis that the slot
width effect is significant. In making the above conclusions, EPA has used 0.05 as the significance level,
as it is widely accepted and commonly used by many researchers. However, the choice of the significance
level is somewhat arbitrary. Slightly relaxing the requirement to a significance level of 0.1 would also be
considered an acceptable and reasonable choice. If a significance level of 0.1 was adopted, then the effect
of slot width on percent reduction would be statistically significant for both total organisms and eggs.
11E-4
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix E
To investigate the effect of slot velocity further, EPA also considered a variation on the
ANOVA model for which the slot velocity effect was represented as a categorical
variable rather than a continuous variable (i.e., similar to how slot width is represented in
the model). Even when slot velocity was represented in this modified form within the
model, the effect of slot velocity on percent reduction continued to be non-significant at
the 0.05 level, and the least squares means showed no discernable pattern.
Thus, based on this analysis, EPA's answer to question #1 is as follows: No statistically
significant differences were observed in average percent reduction in entrained organisms
among different values for either slot velocity or slot width. However, there is some
evidence from the available data that percent reduction is greater at a slot width of 0.5
mm compared to larger widths.
11E.5 Model and Results for Question #2 (effects of slot width
on untransformed percent)
The ANOVA model to address question #2 was a simpler version of the above model as
shown in equation (2). EPA fit this model separately to percent reduction data for eggs
only, larvae only, and total organisms. Because slot velocity was not represented in this
model, it allowed for data associated with studies in which slot velocity was not reported
to be included in the analysis. The equation used in this analysis was:
Yik = ju +0i + elk (2)
where the notation is the same as above. (Statisticians recognize this model as a
classical "one-way" ANOVA model.) Thus, slot velocity is not accounted for in this
model. In addition, under this model, EPA determined from preliminary investigations
that it was not necessary to take log-transformations of the percent reduction data values
in order to satisfy the necessary underlying assumptions of the ANOVA procedures.
Therefore, this model features no log transformation.
To determine whether slot width led to statistically significant differences in percent
reduction data, EPA performed the following statistical hypothesis test:
• Null hypothesis: the values at were each equal to zero (i.e., for each slot width).
• Alternative hypothesis: at least one value «;• was nonzero.
If the significance level of this test was less than 0.05, then EPA concluded that the data
were sufficient for rejecting the null hypothesis in favor of the alternative hypothesis, and
therefore, that slot width was a significant factor in determining percent reduction in
entrainment.
EPA fitted the ANOVA model in Equation (2) separately to percent reduction data for
eggs only, larvae only, and total organisms. Exhibit 1 1E-2 reports the least squares
means for percent reduction in entrainment for each model fit, along with 95 percent
confidence intervals.
11E-5
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Chapter 11: Appendix E
§ 316(b) Existing Facilities Proposed Rule -TDD
Exhibit 11E-2. Least Squares Means for Percent Reduction in Entrainment and 95
Percent
Confidence Intervals, for Each Encountered Slot Width, Under the ANOVA Model Addressing Question #2
Data Set
Total Organisms
Eggs Only
Larvae Only
Slot Width (mm)
0.5
1.0
2.0
3.0
0.5
1.0
3.0
0.5
1.0
2.0
3.0
Least Squares
Mean (%)
66.7
38.0
42.5
24.2
83.6
21.3
27.1
63.7
43.3
42.5
16.1
95% Confidence Interval on Least
Squares Mean
(41.5, 91.9)
(18.8, 57.3)
(17.2,67.7)
(-42.6,91.0)
(54.4, 112.8)
(-10.2,52.9)
(-50.2, 104.4)
(40.2, 87.2)
(25.3,61.2)
(19.0,66.0)
(-46.1,78.3)
Conclusions made from the information in this table and from the statistical tests for
significant slot width effect performed within the ANOVA were as follows:
• Slot width had a significant effect on average percent reduction of eggs (p-value =
0.024), for which data were available for three slot widths (i.e., 0.5 mm, 1.0 mm,
and 3.0 mm). According to Exhibit 11E-2, the largest average percent reduction
in egg entrainment occurred at a slot width of 0.5 mm, and it differed most greatly
with percent reduction at 1.0 mm. (Because only one measurement represented a
slot width of 3.0 mm, its least squares mean has high uncertainty, and its
confidence interval is quite large.)
• Slot width did not have a significant effect on average percent reduction of either
total organisms (p-value = 0.273) or larvae (p-value = 0.337). In both cases, the
highest least squares means occurred at a slot width of 0.5 mm, and the smallest
occurred at 3.0 mm. (However, the 3.0 mm slot width was limited to a single
measurement.) The least squares means at 1.0 mm and 2.0 mm slot widths were
similar.
• When considering only larvae entrainment data, EPA refit the ANOVA model to
data for only the Chesapeake Bay, Portage River, and Sakkonet River studies,
which shared similar experimental designs and which contributed egg entrainment
data. In this analysis, slot width was found to have a significant effect on the
average percent reduction in entrained larvae (p-value = 0.009). Thus, when
studies have different sampling designs and protocols, this may contribute to
increased variation in the reported entrainment data, and therefore, an increased
difficulty in identifying significant differences among slot widths.
Note that when EPA applied a nonparametric form of the ANOVA procedure (using the
Kruskal Wallis test to compare results among different slot widths) rather than the
parametric form used here, the tests yield the same conclusions as above. The Kruskal
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix E
Wallis test does not rely on the assumption that values for percent reduction in entrained
organisms (after accounting for slot width effects) originate from a normal distribution.
Thus, based on this analysis, EPA's answer to question #2 is as follows: Statistically
significant differences were observed in average percent reduction in entrained organisms
among different slot widths for eggs, and as seen in a smaller set of similar studies, for
larvae. The greatest difference occurs between 0.5 mm and 1.0 mm slot widths.
11E.6 Future Refinements
For the final rule, if more data are identified, EPA may consider whether additional
variables can be used to refine the ANOVA model. Any additional variables should have
the following characteristics:
1. The variable is likely to explain variation in the percent reduction of organisms
entrained.
2. Each value of the variable should be associated with data for similar screen sizes
and slot velocities.
In exploring the entrainment data for the proposal, EPA considered other variables
present in the entrainment data set that could be included as predictor variables in the
ANOVA model. EPA may consider these variables or others in refining the ANOVA for
the final rule. The variables include test condition (e.g., plant, test barge), screen
technology, and water body where the test was conducted. Although some of these
variables may not be of primary interest, they could explain some degree of variation in
the data. Such variables are often called nuisance factors. However, from the data
available for the proposal, the entrainment data set represents a combination of data from
many experiments conducted at different time points and under different conditions. As a
result, no observations are available for certain combinations of treatment conditions.
This leads to some confounding in the effects of certain variables. For this reason and the
lack of data for some variables, EPA could not identify additional variables in the current
data set that would provide more predictive ability to the above ANOVA models which
EPA developed for the proposed rule.
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix F
Appendix F to Chapter 11: Generalized Linear Models for
Percent Reduction in Entrained Organisms
11F.O Introduction
This appendix presents the results of a statistical analysis in which generalized linear
models (GLM) were applied to data collected from several studies (and at several
different facilities) that measured entrainment of organisms through fine mesh screens
placed on the intakes to cooling water intake structures. The objective of applying GLM
was to evaluate whether the slot width and/or slot velocity have a statistically significant
impact on the entrainment of organisms through the screens. Section 11.3 of Chapter 11
describes the entrainment data that were used in the analyses presented in this appendix.
The appendix provides a general overview of GLM, presents two types of models, and
summarizes EPA's conclusions.
11F. 1 General Overview of GLM
Generalized linear models are statistical methods that explain the relationship between a
response variable and a set of predictors. They can be used to address the same types of
questions as analysis of variance (ANOVA) methods. However, unlike ANOVA
methods, GLMs can be used to make inferences about the model when the data follow a
distribution other than the normal distribution. GLMs model a transformation of the
mean (called the link function) as a linear combination of the factors under investigation.
For the entrainment data, EPA considered two types of GLMs: Poisson regression and
logistic regression.
11F.2 Poisson Regression
A Poisson regression is often used to model count data. Thus, this model would be
appropriate to apply to the number of entrained organisms. The natural logarithm is the
standard link function used for Poisson regression. Since the density of organisms in
front of the screen is likely to affect the number of organisms entrained, EPA included
that variable as a covariate in the model. The Poisson regression model was as follows:
log(IV) = at + % + 7\og(Dk) + eljh (1)
where 7^ is the number (per unit volume of water, or density) of entrained organisms
associated with the A* study that utilized the /'* slot width and/11 slot velocity, at is a
constant amount that is associated with the /* slot width, /?and y are slope factors, Vj is
they* slot velocity, Dk is the density of organisms measured in front of the screen for the
&th study (representing organisms having the potential for being entrained), and e^ is
random error left unexplained by the model.
HF-l
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Chapter 11: Appendix F § 316(b) Existing Facilities Proposed Rule -TDD
Note that the form of model (1) is very similar to the ANOVA model considered in
Appendix E. If the parameter 7 equals 1 and if we subtract the term \og(Dk) from both
sides of the model, we obtain the following:
log(Yijk I Dk) = a, + (JVj + el]k. (2)
In model (2), the response is the natural logarithm of the relative size of the behind-
screen density and the density in front of the screen. This value is similar to natural
logarithm of the percent reduction, which in this case would equal log(l - Yykl Dk).
Thus, applying ANOVA methods to model (2) would produce similar results to those
obtained in our previous analyses. The distinction of fitting model (1) is that we focus on
entrainment density, we assume that these data follow a Poisson distribution, and we
allow for the possibility that the parameter 7 could deviate from 1 .
EPA fit the Poisson regression model to the data set that included observations for
organisms in the egg stage of development only, the data set that included observations
for organisms in the larval (non-egg) stage of development only, and the data set that
included observations for all types of organisms (egg and non-egg). In this analysis, EPA
excluded observations from St. Johns River, because the entrainment data at this site
were reported as absolute numbers rather than as a density per unit volume of water.
EPA excluded the observation from Big Bend, because preliminary fits of the model
suggested that this observation was an outlier. EPA excluded the 1983 Chalk Point study
that used a screen width of 3 mm because that was the only study that tested that
particular mesh size. Slot velocities for the 1982 Chalk Point studies, which were
missing for previous analyses, were assumed to be 1.0 feet per second, based on
information that EPA obtained from recent site visits.
Based on the results of fitting model (1) to available data, EPA reached the following
conclusions:
• Both screen width and slot velocity were highly significant at explaining the
number of eggs entrained (screen widths-value < 0.0001, slot velocity p- value =
0.0002).
• Screen width was not significant at explaining the number of non-eggs entrained
(p-value = 0.5484) or the number of total organisms entrained (p-value = 0.3413).
Slot velocity was not significant at explaining the number of non-eggs entrained
(p-value = 0.7889) or the number of total organisms entrained (p-value = 0.6916).
• The logarithm of the density of organisms in front of the screen was significant
for all three data sets (eggs only, non-eggs, and total organisms). The point
estimate of the slope parameter 7 was close to 1 in all cases, ranging from 0.94 (all
organisms) to 1.59 (eggs only). This suggests that the fitted model (1) is
reasonably close to model (2).
11F.3 Logistic Regression
EPA also investigated the logistic regression model, a GLM that is appropriate when the
response variable is a percentage. In this model, EPA assumes that the number of
11F-2
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§ 316(b) Existing Facilities Proposed Rule -TDD Chapter 11: Appendix F
potentially entrained organisms equals the density of organisms measured in front of the
screen. The number of entrained organisms then follows a binomial distribution, where
the outcome is either entrained or not entrained. The standard link function in logistic
regression is the logit function. Ifp is a proportion between 0 and 1, then the logit
function is defined as follows:
logit(» =
The logistic regression model was as follows:
lOgit(IV) = Cd + (frj + €yk (3)
where Yyk is the density of entrained organisms divided by the density of organisms
measured in front of the screen for the k* study that utilized the /' slot width and7
velocity, and the remaining model terms are as defined in model (1).
EPA fit the logistic regression model (3) to the same data used to fit the Poisson
regression model (1). The fit of the logistic regression model confirmed the conclusions
reached from the fitted Poisson regression. Specifically, EPA concluded the following:
• Both screen width and slot velocity were highly significant at explaining the
number of eggs entrained (screen width p-value = 0.0003, slot velocity p-value =
0.0049).
• Screen width was not significant at explaining the number of non-eggs entrained
(p-value = 0.4493) or the number of total organisms entrained (p-value = 0.2550).
Slot velocity was not significant at explaining the number of non-eggs entrained
(p-value = 0.8322) or the number of total organisms entrained (p-value = 0.7720).
11F.4 Summary
In summary, the results of fitting GLMs to the entrainment data suggest that both slot
width and slot velocity could significantly explain variation in the number or proportion
of eggs entrained. However, they do not appear to be significant for either total
organisms or organisms in the larval (non-egg) stage of life.
While EPA has not fully evaluated which of the above GLMs is most appropriate to
analyze the available data, a cursory review of the log likelihood statistics suggests that
logistic regression provides a better fit than Poisson regression. However, these statistics
were not adjusted for the different number of parameters in each model, and each method
has its own set of assumptions which may or may not be reasonable given the conditions
of the experiments. For the final rule, EPA will further assess the validity of these
assumptions using the data and understanding of what conditions affect entrainment from
biological and engineering perspectives.
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 12: Analysis of Uncertainty
Chapter 12: Analysis of Uncertainty
12.0 Introduction
Any scientific analysis contains some degree of uncertainty. Data used to develop the
analysis may have inherent flaws, assumptions may not be entirely accurate, or outside
factors may unexpectedly influence the outcome. In many cases, uncertainty can be
reduced by conducting parallel analyses or verifying conclusions via alternate pathways
or data sources. This chapter presents EPA's efforts to identify sources of uncertainty,
evaluate how those uncertainties might affect the analyses, and consequently minimize
the effects of uncertainty associated with its analyses.
12.1 Uncertainty in Technical Analysis of Impingement Mortality
12.1.1 Technology in Place and Related Model Facility Data
The detailed technical questionnaires were conducted more than 10 years prior to this
rule proposal. Changes may have occurred at individual facilities that would affect the
cost and reductions analyses such as number of intakes, intake flow, operational status,
and current technology in place. (EPA did collect more current financial information to
update and revise the economic analysis; see EBA for more information). Based on site
visits and discussions with industry, EPA believes the technical data is still sufficiently
representative of industry operations and can be used to estimate national level costs and
reductions of various regulatory approaches. However, some facilities have installed
impingement and entrainment technologies as a result of the Phase II, state policies, or
other local requirements. As a result, the costs and reductions of the technologies
considered in this proposal are potentially overstated.
12.1.2 Costs of Additional Impingement Mortality Controls
The economic analysis presented in the EBA contains estimated compliance costs for
impingement mortality technologies and, for some options, entrainment mortality
technologies. One uncertainty EPA identified in basing compliance costs on the industry
detailed technical questionnaire is how many coastal or estuarine facilities already use
barrier nets or some equivalent-performing technology for reducing shellfish
impingement mortality. EPA's option 1 would also require a fish handling and return
system for all facilities with traveling screens, including those facilities with an actual
intake screen velocity of less than 0.5 feet per second (fps). EPA's detailed technical
data pre-dates the 2004 Phase II rule, and likely underestimates the number of facilities
already employing modified traveling screens with a fish return, or an equivalent
performing technology. In a sensitivity analysis, EPA estimated total rule costs assuming
zero facilities had technologies to meet either of these requirements. These costs are
presented below.
12-1
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Chapter 12: Analysis of Uncertainty § 316(b) Existing Facilities Proposed Rule - TDD
Barrier Net Costs
The proposed rule requires that all facilities located on oceans, tidal rivers and estuaries
minimize the impingement of shellfish. EPA estimated costs for this requirement by
assigning barrier nets to those facilities that do not already have barrier nets or an
equivalent-performing technology. EPA's technical data does not provide sufficient
detail to determine which facilities already employ a technology that would meet the
requirement. Therefore, EPA's initial cost estimates exclude facilities that met the
0.5 fps intake velocity threshold and that are located on an ocean or estuary from being
assigned additional costs for a barrier net. If EPA were to assume the entire universe of
facilities (in oceans and estuaries) would need barrier nets, the manufacturing sector as a
whole would be assigned an additional $100,000 and electric generators as a whole
would be assigned an additional $4,010,000. Therefore the upper bound estimate of total
rule costs including this requirement would increase option 1 costs by less than 1 percent.
Fish Handling and Return System Costs
The proposed rule requires that all facilities meet a minimum threshold of impingement
mortality or by meeting a 0.5 fps design intake velocity threshold. In addition, the
proposed rule requires fish return and handling for all traveling screens, and a
requirement to eliminate entrapment offish and shellfish. Facilities that were found to be
compliant with the velocity threshold were initially assigned no further compliance costs,
even though some fraction of facilities meeting the maximum intake velocity
requirements use traveling screens. EPA estimated the costs assuming all of these
facilities would need to install new fish handling and return systems assuming all of these
facilities employed existing traveling screen (a reasonable assumption given the
predominance of traveling screen use; see Chapter 4 for more information). However,
EPA does not have current data on the number of traveling screens that would be deemed
"modified" screens, such as Ristroph screens or post-Fletcher modifications. For
example, EPA does not have data on the number of large power plants that have already
modified their intakes as a result of the 2004 Phase II rule. As a result of this uncertainty,
EPA conducted a sensitivity analysis on total costs by revising estimated costs to include
fish handling and return systems (as well as new modified Ristroph screens1) to all
facilities employing conventional traveling screens that were deemed to have met the
0.5 fps threshold.2 In other words, EPA assumed zero facilities have modified screens
with a fish return. Under this conservative assumption, EPA estimates the manufacturing
sector as a whole would be assigned an additional $12.3 million and electric generators as
a whole would be assigned an additional $50.7 million. Therefore, EPA believes the
upper bound estimate of total rule costs including this requirement would increase by
approximately 13 percent. Facilities that have modified screens but do not have a fish
return system would incur considerably less costs, and facilities that already have a fish
return would incur no incremental costs as a result of this requirement. This is further
Technology module 1 was assigned; it includes both the screen replacement costs and costs for a new fish
handling and return system.
2
No additional costs would be assigned to facilities that met the velocity threshold with: modified Ristroph
screens, an offshore intake location (velocity cap or wedgewire), perforated pipe, filter bed, or porous dike.
12-2
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 12: Analysis of Uncertainty
likely a conservative estimate of costs for this requirement because the proposed rule
does not preclude the use of different technologies to meet the requirements; for example,
dual-flow screens and WIP screens would likely meet the rule requirements for fish
return and avoidance of entrapment because these screens have no carry-over, and where
these technologies are feasible vendor data and pilot studies suggest such technologies
are less costly than a retrofit of existing traveling screens; see Chapter 6 for more
information.
12.1.3 Intake Flows for Studies Used to Develop Impingement
Mortality Standards
EPA identified 6 technology studies that best represent the efficacy of Ristroph-type coarse
mesh traveling screens. (See Chapter 11 for more information on the derivation of the
impingement mortality standards.) To enable the development of performance standards,
EPA reviewed documentation to verify the intake flows that correspond to the study
periods in these documents. None of the studies were completely clear in describing the
test conditions, including the intake flows withdrawn during testing. As such, EPA needed
to evaluate the flow rates during the test conditions. EPA reviewed the studies and other
supporting documentation (including summary reports, primary studies, and information
from industry surveys) to determine the design intake flow (DIP) of the cooling water
intake structures (CWIS) tested. The results are presented in Exhibit 12-1 below.
EPA is reasonably confident that the DIFs for the Dunkirk and Huntley studies are
correct, because the design capacity is explicitly stated for the study screens at each
facility. (Whether the screens operated at the DIP for the entire study period is unknown;
EPA assumed they were.) Based on the detailed questionnaires and other available
information, EPA assigned a CWIS-specific DIP to the Arthur Kill and Salem studies.
The DIP is comparable to the DIP identified in site visits and other facility reports. EPA
attempted to contact representatives at both facilities to confirm these assumptions.
Subsequent communication efforts were not successful with either facility.
All further uncertainty analysis associated with the statistical analysis of the IM limits is
addressed in Chapter 11.
12.2 Uncertainty In Technical Analysis of Entralnment Mortality
12.2.1 Intake Location
The ability of a facility to locate an intake structure to significantly reduce entrainment, and
to a lesser extent impingement mortality, depends on waterbody and species found at that
site. Of particular interest is the relationship of ichthyoplankton density to water depth as a
potential technology for reducing I&E mortality. EPA used a Southeast Area Monitoring
and Assessment Program (SEAMAP) database to characterize ichthyoplankton (fish eggs
and larvae) presence, composition, and density within the Gulf (see DCN 9-5200; FDMS
ID EPA-HQ-OW-2004-0002-1956). A plot of average ichthyoplankton densities against
depth at 10 meter intervals (see Exhibit 12-2 below) shows general trends were similar
between egg and larval fish densities. The densities of both declined most rapidly
12-3
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Chapter 12: Analysis of Uncertainty
§ 316(b) Existing Facilities Proposed Rule - TDD
Exhibit 12-1. Intake Flows During Screen Performance Testing
Facility
Name
Arthur
Kill
Dunkirk
Huntley
Salem
Generating
Units/CWISs
Unit 20
Unit 30
Screenhouse
#1, including
Units 1 and 2
Units 67 and
68
Unit 1
(1995 study)
Units 1 and 2
(1997-1998
study)
DIP for Test
CWIS Screens
87MGD
85MGD
92.2 MGD
82.8 MGD
266.4 MGD
532.8 MGD
Notes
Each unit contains 4 screens; only one of the four
screens was upgraded for the study. No information
provided on unit operation during study; assume that
the flow through the upgraded test screen was 0.25
the maximum flow for the unit (347.9 MGD -
provided in study), or 87 MGD.
Each unit contains 4 screens; only one of the four
screens was upgraded for each study. No
information provided on unit operation during study;
assume that the flow through the upgraded test
screen was 0.25 the maximum flow for the unit
(339.3 MGD - provided in study), or 85 MGD.
Modifications were made to one of three existing
screens. No information provided on unit operation
during study; assume flow through the test screen at
maximum capacity. 92.2 MGD specified as
prototype study screen capacity.
All (4 existing) screens replaced at Units 67 and 68
with 5 Ristroph-types screens. No information
provided on unit operation during study; assume flow
through the test screen at maximum capacity. 82.8
MGD specified as prototype study screen capacity.
No information provided on unit operation during
study; assume flow through the test screen at
maximum capacity. 266.4 MGD specified as Unit 1
design flow rate; 1995 study looked only at
performance of Unit 1 screens.
No information provided on unit operation during
study; assume flow through the test screen at
maximum capacity. 266.4 MGD specified as flow
rate at each unit; 1997-1998 study looked at
performance of screens at both Unit 1 and Unit 2 for
a total DIP of 532.8 MGD.
Data
Source(s)
EPRI 2007
EPRI 2007
Beak
Consultants,
Inc., 2000
(DCN 5-4327)
Beak
Consultants,
Inc., 2000
(DCN 5-4325)
Ronafalvy,
Cheesman,
and Matejek,
2000 (DCN 5-
4333)
Ronafalvy,
Cheesman,
and Matejek,
2000 (DCN 5-
4333)
Exhibit 12-2. Average Densities (N/m3) of eggs and ichthyoplankton
sampled at a given maximum depth intervals in the Gulf of Mexico
• ••*•-- IchthyopSank.ton Density
—*—Egg Density
:*.::*
Maximum Sampling Depth (m)
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 12: Analysis of Uncertainty
from 0 to 60 meters in depth. As depth increased past 60 meters, the decline in
ichthyoplankton and egg densities was less pronounced. This is consistent with the
understanding that the euphotic zone (zone light available for photosynthesis) does not
extend beyond the first 100 meters (328 feet) of depth.
The findings of the SEAMAP analysis for the Gulf of Mexico are generally supported by
the cited papers from the Pacific and British coasts and the data from the Gulf of Maine,
i.e., that ichthyoplankton densities increase as depth and distance from shore decrease,
and that abundance is greatest at depths less than 100 meters. These data did not show
consistent or in many cases even a high level of performance as a result of intake
location. Further, as a result of these analyses, EPA has determined only intakes far
offshore in the ocean or Great Lakes could achieve such distances and depths, therefore
the technology is not even available for most facilities. Still other facility data shows that
substantial decreases in density are not observed even far offshore. Therefore, EPA did
not further consider intake location as a candidate technology for national standards.
However, EPA anticipates for some facilities, an intermediate distance/depth/density
where an order of magnitude decrease in density would occur. EPA intends to collect
and review additional source water characterization and density data, and will reassess
intake location as a possible technology.
12.2.2 Space Constraints
Chapter 10 discusses EPA's approach to estimating the number of facilities that would
face space constraints (as well as constraints for noise and tower plume). At some
facility sites, EPA believes retrofitting to closed-cycle cooling is extremely difficult or
perhaps infeasible due to a lack of space for the cooling tower. Space constraints, in
particular water-front acres, may preclude expanding an existing intake structure such as
to reduce intake velocity by adding intake bays or due to fine mesh installations. In the
majority of cases, EPA found dense urban locations simply have no space available on
the site to locate a cooling tower of sufficient size. In many cases the surrounding land is
occupied, making it impossible (or prohibitively expensive) to acquire additional land.
EPA did not assess the costs of additional land purchases in its analysis, because EPA
does not have adequate data on which to predict the number of facilities with space
constraints, their locations, and the availability and costs of neighboring land.
Based on site visits, permits, and other reports, EPA assumed an upper bound of one in
four, or 25 percent, of facilities would face space constraints. EPA based this assumption
on the observation that approximately 95 percent of the 47 sites with a ratio of 160 acres
per 1000 megawatt (MW) and above would have sufficient acreage to retrofit mechanical
draft cooling towers. For the 25 observed sites with a ratio less than 160 acres per 1000
MW, as many as 20 percent of the facilities would likely be space constrained.
Another GIS-based approach EPA analyzed (instead of the population density method
presented in Chapter 10) was to use a data layer from the National Atlas that identified
"urban" areas. Similar to the population density approach, this data layer would identify
areas that are likely to have high densities of populated space and would be the most
likely to face significant challenges in siting a retrofit cooling tower.
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Chapter 12: Analysis of Uncertainty § 316(b) Existing Facilities Proposed Rule - TDD
The urban GIS layer identified a similar profile for land availability. For example, it
identified approximately 30 percent of facilities as located in an urban area (as examined
by the number of facilities, percentage of total flow, and percentage of total cost).3
Electric generators were identified as urban slightly less often and manufacturers were
identified slightly more often. Small businesses were much less likely to be identified as
urban.
The primary drawback of this data was that it was not clear how the urban identification
had been designated. Given the similarities in the two approaches and their projected
outcomes, EPA opted to use the population density approach, as it provides a better
defined and more reliable algorithm.
EPRI reported at least 6 percent of sites evaluated were deemed "infeasible" on the basis
that no space was available on which to locate a cooling tower. (See DCN 10-6951.)
While EPA does not have access to the facility level data, and is therefore unable to
confirm the infeasibility analysis, EPRI's report supports EPA's assertion that there is
significant uncertainty around space constraints for facilities to install closed-cycle
cooling.
12.2.3 Development of Cooling Tower Costs
In the Phase I and 2004 Phase II rules, EPA used a cost estimation approach that it
developed to calculate estimated costs for closed-cycle cooling. This approach was
derived from cost modules that specify the necessary activities, materials, and
contingencies that comprise the total cost.
In 2007, EPRI provided a new cost estimation tool to EPA. The EPRI tool calculated
costs based on documentation for over 50 closed-cycle retrofits and detailed feasibility
studies. EPA also used cooling tower engineering assessments conducted for California
as part of the Policy on the Use of Coastal and Estuarine Waters for Power Plant Cooling.
These detailed assessments were conducted on 19 existing coastal plants. Maulbetsch
and others have documented cooling tower assessments and presented such findings in
symposiums and proceedings; for example see "Issues Associated with Retrofitting
Coastal Power Plants" (DCN 10-6955) and "Water Conserving Cooling Status and
Needs" Energy-Water Needs" (DCN 10-6953).
Exhibit 12-2 provides a comparison of the cooling tower compliance costs derived using
the EPRI Tower Calculation Worksheet to compliance costs derived using the EPA
Methodology used in 2004 Phase II for an option where cooling towers were retrofitted to
facilities on estuaries and oceans. The costs are for a 350 MW facility with a cooling
water flow of 200,000 gallons per minute (gpm) (288 million gallons per day [MGD]).
The 2004 EPA costs are adjusted to 2007 dollars. It is assumed that the costs shown
contain comparable structural components although it is not known whether the EPRI
costs include condenser upgrades so this element of the 2004 EPA costs is shown
EPA also examined the universe of facilities by waterbody type, state, cooling system type, capacity
utilization, fuel type, and manufacturing sector. In each case, there were no significant trends that would
affect the broader assumption that approximately 30 percent of facilities are in an urban location.
12-6
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 12: Analysis of Uncertainty
separately (not all cooling tower retrofits require condenser upgrades therefore EPA's
costs would not apply condenser upgrade costs to all facilities). The 2004 EPA costs
shown do not include any intake modification costs. EPA operations and maintenance
(O&M) costs are for gross O&M meaning they do not include reductions for baseline
technology O&M such as once through pumping energy costs. Therefore EPA's O&M
are potentially overstated.
Exhibit 12-3 shows that the two costing methodologies produce similar results. While the
2004 EPA non-nuclear and nuclear facility capital costs are comparable to the EPRI "easy"
and "average" costs, the EPA's O&M cost are higher for nuclear facilities. The highest and
lowest total annualized costs (based on 20-year service life and discount rate of 5 percent)
cover a similar span for both methodologies especially if condenser upgrades are included.
Thus, use of either method should produce comparable national costs.
Exhibit 12-3. Cost Comparison for a 350 MW Plant with Cooling Flow of 200,000
gpm (288 MGD)
EPA
Phase
II
EPRI
Costs
Tower
Type
Redwood
Tower
Redwood
Tower -
Nuclear
Easy
Average
Difficult
Capital Costs -
Tower and
Piping
$27,000,000
$49,000,000
$32,000,000
$53,000,000
$83,000,000
Condenser
Upgrade
$5,200,000
$9,400,000
-
-
-
O&M
Included in
O&M Total
Included in
O&M Total
$260,000
$260,000
$260,000
Tower
Electricity
Usage
(Pumps &
Fans)
Included in
O&M Total
Included in
O&M Total
$2,600,000
$2,600,000
$2,600,000
O&M Total2
$2,900,000
$4,200,000
$2,860,000
$2,860,000
$2,860,000
Annualized
Capital Not
Including
Condenser
Upgrade
$2,200,000
$3,900,000
$2,600,000
$4,200,000
$6,600,000
Annualized
Condenser
Upgrade
$400,000
$800,000
-
-
-
Total
Annualized
Cost Not
Including
Condenser
Uosrade
$5,100,000
$8,100,000
$5,460,000
$7,060,000
$9,460,000
Annual
Heat Rate
Penalty4
7
7
$1,040,000
$1,040,000
$1,040,000
EPA did not include full condenser upgrade costs at all facilities. Not sure If EPRI included them
2 O&M shown does not include deduction for baseline O&M pumping energy
3 Annualized Capital Cost Factor (20 yr at 5%) = 0.08
4 Heat rate penalty not included in O&M total or Total Annualized Cost
The advantages of using the EPRI costing approach include:
• It can produce a range of capital costs (i.e., the ability to use easy, average and
difficult settings);
• The underlying data is based on actual retrofits, and is likely a more robust
representation of costs;
• The EPRI worksheet can be readily modified to generate facility costs while the
EPA method is more complex and would require considerable spreadsheet
development;
• Input variables can be readily generated; and
• The methodology generates all costs including the energy penalty costs.
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Chapter 12: Analysis of Uncertainty
§ 316(b) Existing Facilities Proposed Rule - TDD
12.3 Uncertainty in Benefits ofl&E Controls
12.3.1 Reductions in Impingement and Entrainment by Region
EPA's analysis of reductions used 96 studies across the seven EPA Benefits Regions
(see the EEBA for further information). There are four major kinds of uncertainty that
may lead to imprecision and bias in EPA's I&E mortality analysis: data, structural,
statistical, and engineering uncertainty. These are discussed in detail in section 1.1 of the
EEBA. In response to these potential limitations, EPA conducted a sensitivity analysis
exploring the extent to which baseline impingement and entrainment (I&E), and therefore
the corresponding potential reductions in I&E attributable to installation of compliance
technology, changes as a result of combining or isolating studies in the various benefits
regions. The studies I and E losses on a per unit flow (MOD) basis are presented in terms
of Age-1 Equivalents in Exhibit 12-4.
Exhibit 12-4. Impingement and Entrainment Losses Per Unit Flow
Region
(Freshwater Regions)
Inland (all)
Great Lakes
subtotal
(Marine Regions)
California Coastal
Mid-Atlantic
North Atlantic
Gulf of Mexico
South Atlantic
subtotal
Total for all regions
Studies
44
11
55
18
12
6
3
2
41
96
AIF
139,178
19,047
158,225
12,300
28,165
7,037
13,246
7,462
68,210
226,435
Average
Study I
loss in A1E
per MGD
4,063
2,504
Average
Study E
loss in A1E
per MGD
1,653
22,558
I
losses in
A1 E per
MGD
4,457
2,489
514
4,532
113
8,073
7,064
4,249
E
losses in
AlEper
MGD
1,924
569
23,242
33,697
11,919
9,722
735
7,648
It appears impingement dominates the total A1E in freshwater systems, and entrainment
dominates the marine regions. Due to the limited number of studies in certain regions,
EPA next combined studies in those regions and recalculated the national baseline I&E.
Due to most studies being conducted on waterbodies in the inland region, EPA also
combined all studies by salinity, i.e., a freshwater region and a marine region. Finally,
EPA combined all studies into one national region. In each case, the weight of the study
(based on the actual flows reported in each study) was kept the same. In all scenarios,
EPA found the change in baseline I&E increased as shown Exhibit 12-5.
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§ 316(b) Existing Facilities Proposed Rule - TDD
Chapter 12: Analysis of Uncertainty
Exhibit 12-5. Changes in Baseline Impingement and Entrainment
Method of combining studies
without changing the weight of each
study
7 regions (current approach)
5 regions: CA, MA, INL, GL, GoM
2 regions, AIF wtd avg
all regions total value
2 regions, freshwater and marine,
study average
6 regions (GoM and SA combined)
5 regions (GoM + SA, NA+MA
combined)
National
baseline 1
(A1E)
9.49E+08
1.01E+09
8.56E+08
1.01E+09
8.56E+08
9.56E+08
1.00E+09
National
baseline E
(A1E)
1.52E+09
2.21 E+09
1.86E+09
1.82E+09
1.86E+09
1.58E+09
1.80E+09
National
baseline I&E
combined
(A1E)
2.47E+09
3.23E+09
2.71 E+09
2.83E+09
2.72E+09
2.54E+09
2.81 E+09
% change in
national
baseline over
current
approach
—
131
110
115
110
103
114
This uncertainty analysis suggests potential bias is accentuated when combining studies
from different waterbodies. In particular, the extremely small number of studies in the
Gulf of Mexico and the South Atlantic regions, and the significantly lower I&E attributed
to those regions, is highlighted. Studies in other waterbodies show higher I&E baseline
estimates, suggesting the national baseline could be as much as one-third higher than the
currently used approach to regional benefits analysis. Further, there is considerable
variability observed in I, E, and I&E combined (as measured in A1E). To reduce the
uncertainty, EPA intends to collect additional studies in all regions, solicit data in the
proposed rule, and revise the baseline I&E calculations accordingly.
12.3.2 Air Emissions Associated with Closed-Cycle
Fossil-fueled facilities may need to burn additional fuel (thereby emitting additional CC>2,
SC>2, NOx, and Hg) for two reasons: 1) to compensate for energy required to operate
cooling towers, and 2) slightly lower generating efficiency attributed to higher turbine
back pressure. In general, EPA expects national level emissions may increase in the short
term, but decrease over the long term as facilities upgrade the oldest units by replacing
condensers and boilers. U.S. fleet efficiency will likely increase over the long term,
resulting in lower base emissions on a per watt basis, and the turbine back pressure
penalty will be further reduced resulting in lower incremental emissions.
EPA's projected emissions due to cooling tower energy penalties include several sources
of uncertainty. EPA's economic analysis of a cooling towers based rule indicates that
some units and a few facilities may close as a result of the proposed rule. The IPM
modeling used in EPA's economic analysis indicates any closures of generating units are
generally comprised of the oldest and least efficient (and therefore the highest emitting)
units, resulting in a potential reduction in total air emissions as a result of these closures;
4 In its comments on the Phase II rule (see DCN 6-5049, authors 316bEFR.211 and 316bEFR.214), the
Department of Energy (DOE) predicts energy penalties ranging from 2.4 to 4.0 percent for conversion to
wet cooling towers by Phase II facilities, i.e., electric generators with a DIP of greater than 50 MOD. DOE
applied these penalties to case study regions and projected less than 1 percent emissions increases.
12-9
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Chapter 12: Analysis of Uncertainty
§ 316(b) Existing Facilities Proposed Rule - TDD
see the EBA for more information on this specific assessment. Additional capacity
brought online to replace these facility closures will be more efficient units. In addition,
the current emissions rate calculations do not reflect full implementation of the most recent
air rules. For example, the 2010 Air Transport Rule and other state and EPA actions would
reduce power plant SO2 emissions by 71 percent, and NOX emissions by 52 percent. The
mercury rule would require utilities to install controls to reduce mercury emissions by 29
percent. Since the actual emissions data used in EPA's analysis does not reflect full
implementation of these air rules, and since in some cases technologies to reduce emissions
have yet to be installed, both the baseline and any potential increase in emissions are
overstated. Finally, the latest tower fill materials and other cooling tower technology
improvements provide increases in cooling capacity. In some cases cooling towers provide
cooling water at lower temperatures than available from the source water, resulting in lower
turbine back pressure in the summer when maximum power generation is desired.
EPA's emissions estimates also include emissions (drift) from the cooling towers
themselves. Drift consists of water droplets exiting the cooling tower. Drift can result in
formation of particulate matter (primarily PMio) when the droplets evaporate before hitting
the ground. Current cooling tower designs minimize drift to less than 0.1 percent of the
circulation flow. Sustained winds and high humidity must be present for drift to reach
distances of several hundred feet, therefore most power plants will not have any adverse
impacts due to drift. The options considered include costs for drift eliminators - additional
technology installed on the top of the cooling tower to further reduce drift to 0.0005 percent
of the circulating flow. EPA has reviewed non-attainment areas for PMio and has found
many power plants in these areas are using dry cooling, which avoids any issues with drift.
Exhibit 12-6. Map of Non-Attainment Areas for PMIO
.V/« sag
. -V;.//.- >'*•*•*
•*-V* ". /•*.
•; > • j««
r/^-r^b. •-.•--
k
Legend
• Plant_ Locations
I PM10 Nonattainment counties Source; U.S. EPA Office of Air and Radiation, AQS Database.
12-10
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§ 316(b) Existing Facilities Proposed Rule - TDD Chapter 12: Analysis of Uncertainty
Chapter 10 discusses the methodology to estimate incremental increases in such air
pollutant emissions from retrofitting cooling towers. The approach used a generic
modeling of particulate matter emissions from the cooling towers, but more site-specific
analyses often use air quality modeling method AP-42. For example, Chapter 8 of EPA's
"Emission Estimation Protocol for Petroleum Refineries" specifies ranked approaches to
estimating losses from cooling towers. Methodology Rank 5 for cooling towers uses the
total liquid drift emission factor given in AP-42 (U.S. EPA, 1995) of 1.7 Ib of drift per
1,000 gallons of water (lb/103 gal) for induced draft cooling towers and the total
dissolved solids (TDS) weight fraction to estimate PM-10 emissions. This is a
conservative PM-10 emission factor in that it assumes that all TDS are in the PM-10 size
range. Peer review of EPA's Office of Air Quality has further identified the method AP-
42 frequently overestimates emissions.5 The site-specific TDS fraction in the cooling
water should be used when available, the site-specific TDS fraction can be estimated
from the TDS of the makeup water and the cycles of concentration ratio (ratio of the
measured parameter for the cooling tower water such as conductivity, calcium, chlorides,
or phosphate, to the measured parameter for the makeup water), when these data are
available. The following two examples of PM-10 emissions estimates calculations (DCN
10-6899) provide an additional method by which EPA can quantify an upper bound of
PM emissions from cooling towers.
In addition to the uncertainty over annual baseline emissions generated and the
uncertainty over incremental increases in emissions, there is uncertainty over the
environmental impacts of emissions. Four of the 15 largest users of cooling water obtain
cooling water from a freshwater source; more than half of all existing facilities withdraw
water from an inland fresh water river, stream, or lake. The potential for drift formation
is highest where cooling water withdrawals are obtained from a saltwater environment.
Further, sustained winds and high humidity must be present for drift to reach distances of
several hundred feet. A review of EPA's technical questionnaires shows that 10 of the 15
largest users of cooling water (representing more than 12 percent of the total national
potential withdraws) are nuclear facilities. Nuclear facilities tend to have setbacks,
security perimeters, and other boundaries that are significantly distant from the
generating facility that drift is unlikely to land beyond the facility property lines.
However, due to the uncertainty of these site-specific factors, EPA is unable to conclude
that drift will not result in an environmental impact.
See http://www.epa.gov/ttn/chief/efipac/protocol/refinerv emissions protocol vpeer review.pdf.
12-11
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Chapter 12: Analysis of Uncertainty
§ 316(b) Existing Facilities Proposed Rule - TDD
Example 8-6: Calculation
Given: For PM-10 emission:
is servicing a heat exchange
default average IDS weighl
should be used to calculate
1 ^ Ib drift ^mQSi
"FMW '"lO'gal "•"""" i
Example 8-7: Calculation 1
Given: For PM-10 emissions
that is sampled monthly for
measurements, equation (E
1 Date
Jan 10 (startup Jan 1)
February 4
March 4
April 4
May 4
June 4
July 4
August 4
September 4
October 4
November 4
December (shutdown Dec
1 - not operating in
December)
Total
or Methodology Rank 5
; from a cooling tower wit
;r cooling a gasoline strea
fraction of 0.0206 (or 20,
the annual emissions of F
bWS 25.000 gal *&aia *
} drift " niii fir
or Annual Emissions fr<
> from a cooling tower wit
IDS. Using the site-speci
q. 8-9) should be used to
2 IDS Concentration
(ppmw)
360
520
780
1,100
1,260
2,300
3,500
5,500
4,600
1,700
2,100
(2,100 - Use value
from previous month)
for Cooling Towers
-\ a water recirculation rate of 25,000 gal/min, that
m, and that is in service all year. Using the
500 ppmw), the following equation (Eq. 8-9)
>M-10, EPM10:
c.^^* Iton „,„ ton PM-10
w- 2000 Ib " " ,w
am Cooling Towers
i a water recirculation rate of 25,000 gal/min and
fie TDS fraction and the operating hours between
calculate the annual emissions of PM-10, EPNIIO.
3 Hours
96
600
672
720
720
744
720
744
744
720
744
(648)
7,872
4 Emissions
(ton/month)
0.044
0.398
0.668
1.01
1.16
2.18
3.21
5.22
4.36
1.56
1.99
1.73
24 ton/yr
12.4 References
Electric Power Research Institute (EPRI). 2007. Fish Protection at Cooling Water
Intakes: A Technical Reference Manual.
U.S. EPA (Environmental Protection Agency). 1995. Compilation of Air Pollutant
Emission Factors. Volume 1: Stationary Point and Area Sources. AP-42, Fifth
Edition. Office of Air Quality Planning and Standards, Research Triangle Park,
NC.
12-12
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