Progress in Water Quality:
An Evaluation of the National Investment
in Municipal Wastewater Treatment
^ Prepared by:
^ Tetra Tech, Inc.
^j Fairfax, VA
^ and
Andrew Stoddard & Associates
Hamilton, VA
Prepared for:
U.S. Environmental Protection Agency
Office of Wastewater Management
Washington, DC
June, 2000
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Ftoflf
Chicago. IL 60604-3590
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Dedication
This effort to document the water quality benefits associated with
the federal funding provided through the Construction Grants Program
and Clean Water State Revolving Fund (CWSRF) Program to help
plan, design and construct publicly owned treatment works (POTWs)
was initiated at the request of Michael J. Quigley while he served as
Director of the Office of Municipal Pollution Control. It is dedicated to
the many hardworking and conscientious individuals—including the
program advocates and critics alike—who help manage, direct (or in
some cases redirect), and implement the Construction Grants and
CWSRF Programs, which are among the Nation's largest public works
programs, in a highly professional and effective manner. They include
many EPA and state program managers and staff and local wastewater
authority managers and staff, as well as the many highly qualified
consultants and contractors who help the local authorities conduct the
necessary studies, develop the required facilities plans and project design
documents, and construct and operate the treatment facilities that were
established or upgraded with funding from these highly successful public
works programs.
The document could not have been written without the extensive
water quality monitoring efforts across the country undertaken by a legion
of highly qualified field staff and researchers for many local authorities,
state and federal agencies, and colleges and universities. Their efforts
produced the extensive water quality data available in the STORET
database system and local reports, as well as the water quality models
and local assessments that served as the basis for the analyses undertaken
and reported on in this document.
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Contents
Foreword ix
Acknowledgments xi
Acronyms xiii
Executive Summary ES-1
Chapter 1—Introduction 1-1
Background 1-2
Study Approach 1-4
The First Leg: An Examination of BOD Loadings Before and After the CWA 1-5
The Second Leg: An Examination of "Worst-Case" DO in Waterways
Below Point Sources Before and After the CWA 1-6
The Third Leg: Case Study Assessments of Water Quality 1-12
The Audience For This Report 1-13
References 1-14
Chapter 2—An Examination of BOD Loadings Before and After the CWA 2-1
A. Historical Consequences of Ignoring the Wastewater Treatment Component
of the Urban Water Cycle 2-2
Impacts on Water Supply Users and "The Great Sanitary Awakening" 2-3
Impacts on Water Resource Users 2-5
B. Evolution of Wastewater and the Use of DO and BOD as Indicators of Water Quality 2-7
Primary Treatment 2-7
Dissolved Oxygen as an Indicator of Water Quality 2-7
Secondary Treatment 2-9
Biochemical Oxygen Demand (BOD) as a Measure of Organic Wasteload Strength 2-10
C. The Federal Role in Implementing Secondary Treatment in the Nation's POTWs 2-11
The Federal Role in Secondary Treatment Before the Clean Water Act 2-11
The Federal Role in Secondary Treatment After the Clean Water Act 2-18
D. Nationwide Trends in BOD Loading Based on Population and POTW Treatment Design 2-26
Types of BOD Reported in This Trends Analysis 2-28
Trends in POTW Inventory 2-31
Trends in Population and Influent Wastewater Flow to POTWs 2-32
Trends in Influent BOD Loading to POTWs 2-35
Trends in Effluent BOD Loading from POTWs 2-38
Trends in BOD Removal Efficiency 2-43
Future Trends in BOD Effluent Loading 2-45
E. Comparison of Contemporary BOD5 Loadings From POTWs and Other Point and Nonpoint
Sources Based on Estimates of Actual Loadings 2-48
Pollutant Loading From Sources Other Than POTWs 2-49
Estimates of Contemporary (ca. 1995) BOD Loading Using the National Water
Pollution Control Assessment Model (NWPCAM) 2-53
Comparison of Point and Nonpoint Sources of BOD5 at the National Level 2-63
F. Investment Costs for Water Pollution Control Infrastructure 2-63
The Construction Grants Program 2-63
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Other Investment Cost for Water Pollution Control Infrastructure 2-66
Future Infrastructure Needs 2-67
G. Summary, Conclusions, and Future Trends 2-68
Key Points of the Background Sections 2-68
Key Points of the BOD Loading Analysis Sections 2-69
Key Points of the Investment Costs Section 2-71
Conclusions and Future Trends 2-72
References 2-73
Chapter 3—An Examination of "Worst-Case" DO in Waterways Below Point Sources
Before and After the CWA 3-1
A. Background 3-2
Sources of DO Data 3-3
"Worst Case" Conditions as a Screening Tool 3-5
The Role of Spatial Scale in This Analysis 3-12
B. DataMining 3-13
Step 1—Data Selection Rules 3-13
Step 2—Data Aggregation Rules From a Temporal Perspective 3-14
Step 3—Calculation of the Worst-Case DO Summary Statistic Rules 3-14
Step 4—Spatial Assessment Rules 3-15
Step 5—Data Aggregation Rules From a Spatial Perspective 3-18
Step 6—Development of the Paired Data Sets (at each spatial scale) 3-19
C. Comparison of Worst-Case DO in Waterways Below Point Source Discharges
Before and After the CWA at Three Spatial Scales 3-20
Reach Scale 3-20
Catalog Unit Scale 3-25
Comparison of the Change in Signal Between the Reach and Catalog Unit Scales
Using the Upper White River Basin (Indiana) as an Example 3-33
Major River Basins 3-38
D. Summary and Conclusions 3-43
Key Points of the Background Section 3-43
Key Points of the Data Mining Section 3-44
Key Points of the Comparative Analysis Section 3-45
Conclusions 3-47
References 3-51
Chapter 4—Case Study Assessments of Water Quality 4-1
A. Background 4-2
B. Selection of Case Study Waterways 4-4
C. Before and After CWA 4-6
D. Policy Scenarios for Municipal Effluent Discharges 4-8
E. Discussion and Conclusions 4-10
References 4-12
Chapter 5—Connecticut River Case Study 5-1
Background 5-1
Physical Setting and Hydrology 5-2
Population, Water, and Land Use Trends 5-4
Historical Water Quality Issues 5-5
Legislative and Regulatory History 5-6
Impacts of Wastewater Treatment: Pollutant Loading and Water Quality Trends 5-6
VI
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Impacts of Wastewater Treatment: Recreational and Living Resources Trends 5-9
Summary and Conclusions 5-10
References 5-11
Chapter 6—Hudson-Raritan Estuary Case Study 6-1
Background 6-1
Physical Setting and Hydrology 6-2
Population, Water, and Land Use Trends 6-4
Historical Water Quality Issues 6-6
Legislative and Regulatory History 6-9
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 6-10
Impact of Wastewater Treatment: Recreational and Living Resources Trends 6-20
Summary and Conclusions 6-25
References 6-27
Chapter 7—Delaware Estuary Case Study 7-1
Physical Setting and Hydrology 7-2
Population, Water, and Land Use Trends 7-4
Historical Water Quality Issues 7-6
Legislative and Regulatory History 7-7
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 7-8
Evaluation of Water Quality Benefits Following Treatment Plant Upgrade 7-13
Impact of Wastewater Treatment: Recreational and Living Resources Trends 7-17
Summary and Conclusions 7-21
References 7-23
Chapter 8—Potomac Estuary Case Study 8-1
Physical Setting and Hydrology 8-3
Population, Water, and Land Use Trends 8-4
Historical Water Quality Issues 8-5
Legislative & Regulatory History 8-5
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 8-6
Evaluation of Water Quality Benefits Following Treatment Plant Upgrades 8-8
Impact of Wastewater Treatment: Recreational and Living Resources Trends 8-11
Designated Uses & Bacterial Trends 8-11
Submerged Aquatic Vegetation, Fishery, and Waterfowl Resources 8-12
Trends In Suspended Solids Load and Water Clarity 8-13
SAV and Ecological Resources 8-18
Summary and Conclusions 8-18
References 8-18
Chapter 9—James River Estuary Case Study 9-1
Physical Setting and Hydrology 9-1
Population Trends 9-3
Historical Water Quality Issues 9-5
Legislative and Regulatory History 9-5
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 9-6
Evaluation of Water Quality Benefits Following Treatment Plant Upgrades 9-11
Impact of Wastewater Treatment: Recreational and Living Resources Trends 9-13
Summary and Conclusions 9-14
References 9-15
VII
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Chapter 10—Upper Chattahoochee River Case Study 10-1
Physical Setting and Hydrology 10-2
Population, Water, and Land Use Trends 10-4
Historical Water Quality Issues 10-6
Legislative and Regulatory History 10-7
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 10-9
Impact of Wastewater Treatment: Recreational and Living Resources Trends 10-12
Summary and Conclusions 10-13
References 10-14
Chapter 11—Ohio River Case Study 11-1
Physical Setting and Hydrology 11-2
Population, Water, and Land Use Trends 11-4
Historical Water Quality Issues 11-5
Legislative and Regulatory History 11-5
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 11-7
Impact of Wastewater Treatment: Recreational and Living Resources Trends 11-10
Summary and Conclusions 11-12
References 11-12
Chapter 12—Upper Mississippi River Case Study 12-1
Physical Setting and Hydrology 12-2
Population, Water, and Land Use Trends 12-5
Historical Water Quality Issues 12-6
Legislative and Regulatory History 12-10
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 12-12
Evaluation of Water Quality Benefits Following Treatment Plant Upgrades 12-20
Impact of Wastewater Treatment: Recreational and Living Resources Trends 12-23
Summary and Conclusions 12-26
References 12-29
Chapter 13—Willamette River Case Study 13-1
Physical Setting and Hydrology 13-2
Population, Water, and Land Use Trends 13-4
Historical Water Quality Issues 13-5
Legislative and Regulatory History 13-6
Impact of Wastewater Treatment: Pollutant Loading and Water Quality Trends 13-7
Impact of Wastewater Treatment: Recreational and Living Resources Trends 13-9
Summary and Conclusions 13-11
References 13-11
Appendix A—Summary of Peer Review Team Comments and Study Authors' Responses
Appendix B—National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Appendix C—National Public and Private Sector Investment in Water Pollution Control
Appendix D—Before and After CWA Changes in 10th Percentile Dissolved Oxygen and 90th Percentile
BOD5 at the Catalog Unit Level
Appendix E—Before and After CWA Changes in 10th Percentile Dissolved Oxygen at the RF1 Reach Level
Glossary
VIII
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Foreword
This document was prepared under the sponsorship of several programs in the EPA Office of Water
primarily to document the water quality benefits associated with the more than 16,000 publicly owned
treatment works (POTWs) across the country. It emphasizes the role of the Construction Grants Program,
which provided $61.1 billion in federal grants to local authorities from 1972 through 1995 to help support
the planning, design, and construction of POTWs to meet the minimum treatment technology requirements
established by the secondary treatment regulations or water quality standards (where applicable). The
program has also provided more than $ 16 billion under the Clean Water State Revolving Fund (CWSRF)
Loan Programs as capitalization grants to the states since 1988 to support a wide range of water quality
improvement projects. The document was subjected to a formal peer review process that included detailed
reviews and input from NO AA, USGS, AMSA, NRDC, NRC/NAS, NWRI, University of North Caro-
lina, Johns Hopkins University, University of Alabama, states, consultants, local authorities, and others.
The document contains an executive summary and 13 chapters, including a background chapter, and
chapters addressing BOD loadings before and after the Clean Water Act, the "worst case" dissolved
oxygen (DO) levels in waterways downstream of point sources before and after the CWA, and nine case
study assessments of water quality changes associated with POTW discharges.
The report presents the results of a unique, three-way approach for addressing such frequently asked
questions as:
1. Has the CWA regulation of POTW discharges been a success?
2. How does the Nation's water quality before the 1972 FWPCA Amendments compare with the
water quality conditions after secondary and better treatment was implemented?
3. Has the reduction of biochemical oxygen demand (BOD) loadings to surface waters from POTWs
resulted in improved water quality in the Nation's waterways? If so, to what extent?
By examining the numbers and characteristics of POTWs, their populations served, and BOD loadings
on a nationwide basis before and after the CWA, we were able to document changes in the number of
people served by POTWs and the level of treatment provided, the amount of BOD discharged to the
Nation's waterways, and the aggregate BOD removal efficiencies of the POTWs, while providing insight
into the likely impact of future discharges if treatment efficiencies aren't improved to accommodate eco-
nomic growth and expansions in service population.
We examined the "worst case" historical DO levels in waterways located downstream of point sources
before and after the CWA in a systematic manner. By identifying water quality station records that related
to the water quality impact of point source discharges from the "noise" of millions of historical records
archived in STORET, and using DO as our indicator of water quality responses to long-term changes in
BOD loadings from POTWs, we evaluated changes in DO for only those stations on receiving waters
affected by point sources over time under comparable worst-case low-flow conditions (during July-Sep-
tember in 1961 -1965 for before CWA and 1986-1990 for after CWA) using only surface (within 2 meters
of the surface) DO data. We documented significant improvements in worst-case summer DO conditions at
three different spatial scales, in two-thirds of the reaches, catalog units and major river basins.
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Case study assessments were also completed on nine urban waterways with historically documented
water pollution problems. These case study sites included the Connecticut River, Hudson-Raritan Estuary,
Delaware Estuary, Potomac Estuary, James Estuary, Chattahoochee River, Ohio River, Upper Mississippi
River, and Willamette River. Most of the these waterways were sites of interstate enforcement cases from
1957 to 1972, were listed as potential waterways for which state-federal enforcement conferences were
convened in 1963, or were the subjects of water quality evaluation reports prepared for the National
Commission on Water Quality. Two sites were on a 1970 list of the top 10 most polluted rivers. The case
study sites did not include, however, any of the 25 river reaches with the greatest before versus after CWA
improvements in DO found in our study. The case studies characterized long-term trends in population,
point source loadings, ambient water quality, environmental resources, and recreational uses. Validated
water quality models for the Delaware, Potomac, and James estuaries and the Upper Mississippi River
were used to quantify water quality improvements achieved by upgrading POTWs to secondary and higher
levels of treatment. The case study assessments document that tremendous progress has been made in
improving water quality, restoring valuable fisheries and other biological resources, and creating extensive
recreational opportunities (angling, hunting, boating, bird-watching, etc.) in all nine case study sites. At
many of the sites there have been significant increases in species diversity and abundance—returned or
enhanced populations of valuable gamefish (e.g., bass, bluegill, catfish, perch, crappies, sturgeon, etc.) and
migratory fish populations, waterfowl and fish-eating bird populations, opened shellfish beds and more.
Some of the sites have seen a return of abundant mayflies and other pollution-sensitive species, as well as
dramatic increases in recreational boating and fishing. Water quality improvements associated with BOD,
suspended solids, coliform bacteria, heavy metals, nutrients, and algal biomass have been linked to reduc-
tions in municipal and industrial point source loads for many of the case studies.
The unique, three-way approach undertaken by this study quantitatively supports the hypothesis that
the 1972 CWA's regulation of wastewater treatment processes at POTWs has achieved significant suc-
cess—success in terms of reduction of effluent BOD from POTWs, worst-case (summertime, low-flow)
DO improvement in waterways, and overall water quality improvements in urban case study areas with
historically documented water pollution problems. However, the study also points out that without contin-
ued investments and improvements in our wastewater treatment infrastructure, future population growth will
erode away many of the CWA achievements in effluent loading reduction.
Robert K. Bastian
Senior Environmental Scientist
Office of Wastewater Management (4204)
U.S. Environmental Protection Agency
Washington, DC
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Acknowledgments
Principal authors of the report include Andrew Stoddard of Andrew Stoddard & Associates and
Jon Harcum, James Pagenkopf, and Jonathan Simpson of Terra Tech, Inc. The authors gratefully acknowl-
edge the encouragement and support of our Project Officer, Robert K. Bastian, of EPA-OWM. The
authors also gratefully acknowledge the support of Karen Klima, Virginia Kibler, and Dr. Mahesh Podar
(EPA's Office of Water) who contributed to this research effort with their often challenging questions. This
project was funded under the following contracts with the U.S. Environmental Protection Agency: EPA-68-
C3-0303, EPA-68-C1-0008, and EPA Purchase Order No. 7W-0763-NASA.
We gratefully acknowledge the efforts of Alexander Trounov of Terra Tech, Inc. for his expert assis-
tance in the extraction and processing of data from EPA's mainframe databases (STORET, Reach File
Version 1, Permit Compliance System, Clean Water Needs Survey) andUSGS streamflow databases.
Patrick Solomon of Terra Tech, Inc. is acknowledged for his expert assistance in transforming numerous
geographically-based data sets into maps that are works of art. Timothy Bondelid of Research Triangle
Institute is acknowledged for his invaluable contributions of point and nonpoint source loading data, includ-
ing the Reach File Version 1 transport routing database that was developed as part of RTFs National Water
Pollution Control Assessment Model (NWPCAM). With a professional government career in water
pollution investigations that began during the early 1960s, our former colleague at Terra Tech, Inc., Phill
Taylor, is acknowledged for his invaluable insight stimulated by our frequent questions about historical data
archived in STORET. Phill's "corporate memory" and his personal library of reports documenting water
pollution conditions during the 1950s and 1960s were instrumental in the completion of this research effort.
Several state and local agency officials reviewed the case study reports for accuracy and complete-
ness. The authors want to specifically acknowledge the invaluable contributions provided by Alan Stubin
and Tom Brosnan for the Hudson-Raritan estuary case study, Cathy Larson for the Upper Mississippi River
case study, Tyler Richards for the Chattahoochee River case study, Ed Santoro and Richard Albert for the
Delaware estuary case study, and Virginia Carter and Nancy Rybicki for the Potomac estuary case study.
The authors acknowledge the contributions of the late Ralph Sullivan in preparing material on the legislative
and regulatory history of the Federal Water Pollution Control Act. Jim Fitzpatrick (Hydro Qual, Inc.) and
Winston Lung (Enviro Tech, Inc.) are acknowledged for providing water quality model simulation results for
case studies of the Potomac, Delaware, and James estuaries and the Upper Mississippi River. The late Bob
Reimold and his colleagues at Metcalf & Eddy Engineers are acknowledged for their contributions to the
case study of the Connecticut River. The authors also wish to acknowledge the efforts of the Peer Review
Team, whose insight and often critical observations undoubtedly increased the value and credibility of the
study's results. The Peer Review Team includes:
• Mr. Leon Billings
• Mr. Tom Brosnan, National Oceanic and Atmospheric Administration
• Mr. Michael Cook, U.S. Environmental Protection Agency
• Mr. John Dunn, U.S. Environmental Protection Agency
• Dr. Mohammad Habibian, Washington Suburban Sanitation Commission
• Dr. Leo Hetling, Public Health and Environmental Engineering, New York State Department
of Environmental Conservation (retired)
Dr. Russell Isaacs, Massachusetts Department of Environmental Protection
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• Dr. Norbert Jaworski, U.S. Environmental Protection Agency (retired)
• Dr. William Jobin, Blue Nile Associates
• Mr. Ken Kirk, American Metropolitan Sewerage Association
• Mr. John Kosco, U.S. Environmental Protection Agency
• Mr. Rich Kuhlman, U.S. Environmental Protection Agency
• Mr. Joseph Lagnese
• Ms. Jessica Landman, Natural Resource Defense Council
• Mr. Kris Lindstrom, K.P. Lindstrom, Inc.
• Mr. Ronald Linsky, National Water Research Institute
• Dr. Berry Lyons, University of Alabama
• Dr. Alan Mearns, National Oceanic and Atmospheric Administration
• Dr. Daniel Okun, University of North Carolina
• Mr. Steve Parker, National Research Council
• Mr. Richard Smith, U.S. Geological Survey
• Mr. Phill Taylor, U.S. Environmental Protection Agency and Tetra Tech, Inc. (retired)
• Dr. Red Wolman, Johns Hopkins University
The ad hoc case study peer reviewers include:
• Mr. Richard Albert, Delaware River Basin Commission
• Mr. Tom Brosnan, National Oceanic and Atmospheric Administration
• Dr. Virginia Carter, U. S. Geological Survey
• Ms. Linda Henning, St. Paul Metropolitan Council Environmental Services
• Ms. Cathy Larson, St. Paul Metropolitan Council Environmental Services
• Dr. Nancy Rybicki, U.S. Geological Survey
• Mr. Alan Stubin, New York City Department of Environmental Protection
• Mr. Ed Santoro, Delaware River Basin Commission
• Ms. Pat Stevens, Atlanta Regional Commission
• Mr. Peter Tennant, Ohio River Valley Sanitation Commission
Finally, we recognize the cheerful cooperation and expert editing and graphic arts and document
production efforts of Marti Martin, Robert Johnson, Kelly Gathers, Krista Carlson, Emily Faalasli, Elizabeth
Kailey, Melissa DeSantis, and Debby Lewis of Terra Tech, Inc. in Fairfax, Virginia.
XII
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Acronyms
7Q10
AMSA
ASIWPCA
AWT
BOD
BOD5
BODu
C:DW
CBOD
CSO
CTDEP
cu
CWA
CWNS
CWSRF
DMR
DO
FR
FWPCA
FWQA
FY
GAO
GICS
gpcd
HUC
ICPRB
IFD
mgd
MPN
MSA
mt/day
MWCOG
N
NAS
NBOD
NCWQ
NH3-N
NO2-N
NO3-N
NOAA
NPDES
NPS
NRC
10-year, 7-day minimum flow
American Metropolitan Sewerage Association
Association of State and Interstate Water Pollution Control Administration
Advanced wastewater treatment
Biochemical oxygen demand
5-day biochemical oxygen demand
Ultimate biochemical oxygen demand
Carbon-to-dry weight ratio
Carbonaceous biochemical oxygen demand
Combined sewer overflow
Connecticut Department of Environmental Protection
Catalog unit
Clean Water Act
Clean Water Needs Survey
Clean Water State Revolving Fund
Discharge monitoring report
Dissolved oxygen
Federal Register
Federal Water Pollution Control Act/Administration
Federal Water Quality Administration
Fiscal Year
General Accounting Office
Grants Information and Control System
gallons per capita per day
Hydrologic unit catalog
Interstate Commission on Potomac River Basin
Industrial Facilities Discharge File
Million gallons per day
Most probable number
Metropolitan Statistical Area
Metric tons per day (1,000 kg per day)
Metropolitan Washington Council of Governments
Nitrogen
National Academy of Sciences
Nitrogenous biochemical oxygen demand
National Commission on Water Quality
Ammonia nitrogen
Nitrite nitrogen
Nitrate nitrogen
National Oceanic and Atmospheric Administration
National Pollutant Discharge Elimination System
Nonpoint source; also National Park Service
National Research Council
XIII
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NRDC Natural Resources Defense Council
NURP National Urban Runoff Project
NWPCAM National Water Pollution Control Assessment Model
NWRI National Water Research Institute
O Oxygen
O&M Operation and Maintenance
ODEQ Oregon Department of Environmental Quality
OTA Office of Technology Assessment
OWM EPA Office of Wastewater Management
P Phosphorus
PCS Permit Compliance System
PE Population equivalent
PL Public Law
PO4-P Phosphate phosphorus
POC Particulate organic carbon
POM Particulate organic matter
POTW Publicly owned treatment works
QA/QC Quality assurance/quality control
RF1 Reach File 1
SAV Submersed aquatic vegetation
SIC Standard Industrial Classification
STORET EPA's STORage and RETrieval database
TKN Total kj eldahl nitrogen
TN Total nitrogen
TOC Total Organic Carbon
TP Total phosphorus
TPC Typical Pollutant Concentration
TSS Total suspended solids
USAC U.S. Army Corps of Engineers
USCB U.S. Census Bureau
USDA U.S. Department of Agriculture
USDOC U.S. Department of Commerce
USDOI U.S. Department of Interior
USEPA U.S. Environmental Protection Agency
USGS U.S. Geological Survey
USPHS U.S. Public Health Service
WEF Water Environment Federation
WIN Water Infrastructure Network
WPCF Water Pollution Control Federation
XIV
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Progress in Water Quality:
An Evaluation of the National Investment in Municipal Wastewater Treatment
Executive Summary
The existence of serious water
pollution problems in the United
States, first recognized during the 1920s
and 1930s and increasingly well documented
during the 1940s through 1960s, led to the rec-
ognition that the practice of discharging raw
sewage and the use of only primary treatment
in publicly owned treatment works (POTWs)
were generally inadequate technologies for
wastewater disposal.
Excessive loading of organic
matter, nutrients, sediment,
pathogens, and other pollutants
into surface waters, combined
with natural hydrologic (low-
flow) conditions, frequently ac-
counted for incidences of dis-
solved oxygen (DO) depletion,
fish kills, nuisance algal blooms,
and bacterial contamination in
rivers, lakes, and estuaries.
Many of the United States' most
famous water bodies, including
Lake Erie, New York Harbor,
and the Hudson, Upper Mississippi, Potomac,
Chattahoochee, Delaware, and Ohio rivers fell
victim to these symptoms.
In 1948 the 80th Congress encapsulated its frus-
tration with the situation when it declared that
"... The pollution of our water resources by
domestic and industrial wastes has become
an increasingly serious problem for the rapid
growth of our cities and industries. ... Pol-
luted waters menace the public health through
the contamination of water and food sup-
plies, destroy fish and game life, and rob us
of other benefits of our natural resources."
- Senate Report No. 462, 1948
For the first half of
the 20th century,
pollution in the
Nation's urban
waterways resulted in
frequent occurrences
of low dissolved
oxygen, fish kills,
algal blooms,
and bacterial
contamination.
An Increased Federal
Policy Role in the Control
of Water Pollution
National policy for water pollution control has
been legislated primarily in the Federal Water
Pollution Control Act. First passed in 1948, the
act has been amended numerous times (in 1956,
1961,1965,1966,1970,1972,1977,1981 and
1987) to gradually expand the
authority of the federal govern-
ment in regulating pollutant
discharges from point sources
to surface waters. Until enact-
ment of the 1972 (PL 92-500)
and more recent amendments,
now known as the Clean Wa-
ter Act (CWA), the primary au-
thority and responsibility for
water pollution control was at
the state level.
Unfortunately, there was a great
diversity among the states in
terms of ability and willingness
to pay the costs of building and upgrading
POTWs and to enforce pollution control laws.
Lack of local water quality standards, monitor-
ing data, and penalties for violators exacerbated
the situation. Despite 49 joint state-federal en-
forcement conferences that were convened af-
ter the 1965 Amendments to abate critical water
pollution problems, national progress in im-
proving water quality was hindered, in part,
because unless a state formally requested inter-
vention by the federal government, federal au-
thority for regulating discharges was restricted
to interstate and coastal waters.
Public awareness of nationwide water pollution
problems served as a political catalyst to shift
increased authority and responsibility for the
regulation of water pollution control from the
The 1972 CWA
shifted primary
authority for
water pollution
control from
the states to
the federal
government.
ES-1
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states to the federal government. Establishment
of a national policy requiring secondary treatment
of municipal wastewater as the minimum accept-
able technology supplemented by more stringent
water quality-based effluent controls on a site-spe-
cific, as-needed basis was a key provision of the
1972 act. This mandate, coupled with an in-
crease in funding assistance to municipalities
through the Construction Grants Program, led
to a dramatic increase in the number of POTWs
with secondary and advanced treatment capa-
bilities. Congress assumed that these actions
would directly support the long-term goal of
the CWA, the national attainment of "fishable
and swimmable" waters.
Figure 1 ----- —--,— - -- - .. . --
Annual funding provided by USEPA's Construction Grants
and CWSRF Programs to local municipalities for improve-
ments in water pollution control infrastructure from 1970 to
1999. Costs reported in current year dollars. (Data from
USER4 G/CS database and CWSRF Program.)
c:
.o
o
o
"c
0)
8
7-
6-
5-
0
Construction Grants
CWSRF
III
1970 1975 1980 1985 1990 1995 2000
Year
T/ie National Investment In
Municipal Wastewater
Treatment
A total of $61.1 billion ($96.5 billion as con-
stant 1995 dollars) was distributed to munici-
palities through USEPA's Construction Grants
Program in the 25-year period from 1970 to
1995 in support of the CWA's municipal waste-
water treatment program (Figure 1). An addi-
tional $16.1 billion (capitalization) was also dis-
tributed to the states through the Clean Water
State Revolving Fund (CWSRF) Program from
1988 through 1999. Including the state contri-
butions and loan repayments, the CWSRF loan
program assets have grown to over $30 billion
since 1988 and are funding about $3 billion in
water quality projects each year.
In terms of promoting the minimum accept-
able technology-based standard of secondary
treatment nationwide, this investment was an
outstanding success. By 1996 the number of
POTWs offering less than secondary treatment
dwindled to less than 200 (down from 2,435 in
1968 and 4,278 in 1978). Correspondingly,
there was a dramatic increase in the number of
facilities offering secondary treatment or greater
(from 10,052 facilities in 1968 to 13,816 facili-
ties in 1996).
In 1968, 72 percent of the
Nation's POTWs were providing
secondary treatment and less than
1 percent were providing greater
than secondary treatment (out of
14,051 facilities). By 1996, 59
percent of the Nation's POTWs were
providing secondary treatment and
27 percent were providing greater
than secondary treatment (out of
16,024 facilities).
ES-2
Executive Summary
-------
The success of these national investments is also
demonstrated by the increase in the number of
people served by POTWs, which shifted dra-
matically between 1968 (before-CWA) and
1996 (after-CWA), as shown in Figure 2. The
story told in Figure 2 is summarized below.
• The overall number of people served by
POTWs increased from 140.1 million in
1968 to 189.7million in 1996(a 35
percent increase).
• The number of people relying on POTWs
with less than secondary treatment
dropped rapidly after passage of the 1972
CWA. In 1968 about 39 percent (54.2
million) of the 140.1 million people
served by POTWs received less than
secondary treatment (raw and primary).
By 1996 this percentage was reduced to
about 9 percent (17.2 million) of the
189.7 million people served by POTWs.
This 9 percent includes approximately
5.1 million people currently served by
POTWs with CWA Section 301(h)
waivers allowing the discharge of less
than secondary treated effluent to deep,
well-mixed ocean waters.
• While the number of people served by
POTWs with secondary treatment
remained fairly constant between 1968
and 1996 (a slight decrease of 3.7
million people or about 4 percent of the
population), the number of people
provided with greater than secondary
treatment increased significantly (from
0.3 million people in 1968 to 82.9
million people in 1996). Stated another
way, the U.S. population served by
POTWs with secondary or greater
treatment almost doubled between 1968
and 1996from 85.9 million people in
1968 to 164.8 million people in 1996!
.„„,.„„ „__„„„,^__,™~, „.,.„,— Figure 2
Population served by POTWs in 1968 (before th<
CWA) and in 1996 (after the CWA) by treatment type
(Data from U.S. Public Health Service municipa
wastewater inventories; USEPA Clean Water Need;
Surveys; USDOI, 1970; USEPA, 1997.
Raw1 • < Secondary D Secondary D > Secondary i_' No Discharge
200n
•$. 180-
.§ 160-
J. 140-
"g 120-
o> 100
80-
60-
40-
20-
0-
o
I
Q.
O
Q.
Before the CWA (1968)
After the CWA (1996)
Raw discharges were eliminated by 1996.
Data for the "no-discharge" category were unavailable for 1968.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ES-3
-------
Was the Public's Investment In POTWs Worth It?
Questions concerning the environmental ben-
efits, as well as the cost-effectiveness, of the na-
tional investment in municipal wastewater treat-
ment have been raised by Congress and by spe-
cial interest, environmental, and business ad-
vocacy groups. In the 25 years after the enact-
ment of the CWA, studies have attempted to
evaluate progress in achieving the goals of the
CWA by documenting (a) administrative ac-
tions (e.g., numbers of discharge permits and
enforcement actions) and programmatic evalu-
ations (see Adler et al., 1993); (b) trends in na-
tional wastewater infrastructure (e.g., popula-
tion served by secondary or greater treatment
levels, effluent loading rates); (c) state and na-
tional inventories of waterways meeting desig-
nated uses (e.g., 305(b) reports); and (d) changes
in water quality following wastewater treatment
plant upgrades for specific waterways.
Evaluations of water quality conditions in the
United States include a pre-CWA national water
quality analysis of conditions from the 1940s
through the 1960s (Wolman, 1971; USEPA,
1974) and post-CWA assessments of the national
effectiveness of the 1972 CWA (e.g., Smith et
al., 1987a, 1987b). Assessments of local (Isaac,
1991; GAO, 1986), regional (Patricketal., 1992),
and national water quality conditions (Smith et
al., 1992) have demonstrated improvements in
some water quality constituents following up-
grades to secondary or greater levels of wastewa-
ter treatment at municipal facilities.
There is, however, no study that has attempted
a national-scale comprehensive evaluation of the
effectiveness of the CWA's technology- and wa-
ter quality-based effluent control policies in
achieving the "fishable and swimmable" goals
of the act (Mearns, 1995).
STUDY OVERVIEW: The "Three-Legged Stool" Approach
This study takes a unique,
three-pronged approach for an-
swering the prima facie ques-
tion—Has the Clean Water Act's
regulation of wastewater treat-
ment processes at POTWs been
a success? Or posed more di-
rectly, How have the Nation's
water quality conditions changed
since implementation of the
1972 CWA's mandate for sec-
ondary treatment as the mini-
mum acceptable technology for
POTWs?
This study takes a
unique three-pronged
approach to evaluate
nationwide progress
in water quality
conditions since
the enactment of
the 1972 CWA.
The three-pronged approach
described below (and presented
in the companion document,
USEPA, 2000) was developed
so that each study phase could
provide cumulative support
regarding the success, or failure,
of the CWA-mandated POTW
upgrades to secondary and
greater than secondary treat-
ment. Using the analogy of a
three-legged stool, the study
authors believed that each leg
must contribute support to the
premise of CWA success. If one
or more legs fail in this objec-
tive, the stool will be unable to
"stand up."
ES-4
Executive Summary
-------
The First Leg: An
examination of BOD
loadings before and
after the CWA
As increasing numbers of people hooked into
more and upgraded POTWs, there was a corre-
sponding rise in influent BOD1 loading nation-
wide to these facilities. Figure 3 presents the
amount of influent BOD loading to "less than
secondary," secondary, and "greater than second-
ary" facilities for 1968 and 1996 (years repre-
senting before and after the CWA). BOD
loadings are shown both as BOD5 (carbona-
ceous BOD, i.e., oxygen demand from the de-
composition of organic carbon) as well as BODU
(ultimate BOD, which includes nitrogenous
BOD, i.e., oxygen demand from the decom-
position of ammonia and organic nitrogen, in
addition to carbonaceous BOD).
As shown, total influent loading of BOD in-
creased by about 35 percent, from 18,814 to
25,476 metric tons per day. Similarly, total in-
fluent loading of BODy increased by about 35
percent, from 34,693 to 46,979 metric tons per
day. Fortunately, this situation was counteracted
by the CWA wastewater treatment mandates,
which resulted in rising BOD removal efficien-
cies (Figure 3).
In 1968 the national aggregate removal efficien-
cies stood at about 63 percent and 39 percent for
BOD5andBODu, respectively. By 1996national
aggregate removal efficiencies had risen to nearly
85 percent and 65 percent, respectively!
BOD, or" biochemical oxygen demand" is a
measure of the oxygen-consuming organic
matter and ammonia-nitrogen in wastewater.
The higher the BOD loading, the greater the
depletion of oxygen in the waterway.
- -- -— ~ .— Figure ;
Influent and effluent loading of BOD to and from POTW
in 1968 (before the CWA) and in 1996 (after the CWA
by treatment type and associated BOD aggregati
removal efficiencies. (Data from U.S. Public Healtl
Service municipal wastewater inventories; USEPA Cleai
Water Needs Surveys; USDOI, 1970; USEPA, 1997.
I < Secondary D Secondary LJ > Secondary
I
O)
c
Q
O
m
XX
Before the After the
CWA (1968) CWA (1996)
Before the
CWA (1968)
After the
CWA (1996)
Consequently, the net result was decreasing lev-
els of effluent BOD loading to the Nation's wa-
terways (Figure 3). In 1968 the total effluent
loadings for BOD5 and BODU stood at about
6,932 and 21,281 metric tons per day, respec-
tively. By 1996 these amounts had dropped to
3,812 metric tons per day for BOD5 (a 45 per-
cent decline) and 16,325 metric tons per day
for BODy (a 23 percent decline), despite a cor-
responding 35 percent increase in influent BOD
loadings! Since many POTWs operate at even
higher BOD removal efficiencies, these design-
based effluent load reductions are understated,
compared to actual data reported in the Permit
Compliance System (PCS), which may vary
somewhat from year to year.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ES-;
-------
Figure 4
Projections of design-based, national effluent BODU loadings
through 2025 using middle-level U.S. population projections.
(Population projection data from U.S. Census, 1996.)
Assumptions:
Influent flow is a constant 165 gallon/capita-day1 with a BODU of 396.5 mg/L
Projection Results:
Population served (millions)
Percent of total population
Design removal efficiency (BODJ
Effluent BOD,, (metric tons/day)
1968 1972 1978 1996 2016 2025
140.1
71%
39%
141.7
69%
41%
155.2
70%
52%
189.7
72%
65%
275.0 295.0
71%
71%
21,280 20,831 19,147 16,325 19,606 21,090
80,000
70,000 -
Influent BODu
Effluent BODu
Q Removal Efficiency
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
2016 2025
1 165 gal/capita-day is based on the mean of population served and wastewater flow
data in the Clean Water Needs Surveys for 1978 through 1986 and accounts for
residential, commercial, industrial, stormwater, and infiltration and inflow compo-
nents.
be similar to loading
rates experienced in
the mid-1970s, only a
few years after the
CWA!
Based on middle-level
population
projections, effluent
loading rates of
BOD v in 2016 would
The dynamic
relationship be-
tween influent
BOD loading,
BOD design re-
moval efficien-
cy, and effluent
BOD loading creates an important model for
planning new investments in wastewater treat-
ment infrastructure (Figure 4). Based on the data
reported in the 1996 Clean Water Needs Sur-
vey Report to Congress (USEPA, 1997), the
overall design BOD removal efficiency is likely
to increase somewhat because there is an appar-
ent trend toward a higher proportion of ad-
vanced (greater than secondary) POTWs. In the
next 20 years, however, the proportion of the
U.S. population served by POTWs is also likely
to increase as the urban population of the na-
tion increases.
Using the assumptions listed in Figure 4, and
using middle-level population growth projec-
tions from the Census Bureau (U.S. Census,
1996), it was estimated that by 2016 nearly 275
million people will be served by POTWs that
discharge to surface waters. Assuming a 165 gal/
capita-day influent flow and 396.5 mg/L con-
centration of influent BODjj, this growth
(1996-2016) would result in a 45 percent in-
crease in influent BODy loading to POTWs
(68,030 metric tons per day) and a 20 percent
increase in effluent BODy loading to surface
waters (19,606 metric tons per day). These pro-
jected 2016 effluent BOD[J loadings are similar
to levels that existed in the mid-1970s, only a few
years after the CWA! Projecting further into the
future, effluent BOD^, loadings in 2025 (21,090
metric tons per day) would be similar to load-
ing rates experienced in 1968 (21,280 metric
tons per day), when they had reached a historic
maximum level!
ES-6
Executive Summary
-------
These types of projections underscore the im-
portance of the need to continually invest in
improvements to wastewater treatment infra-
structure in order to maintain and improve pol-
lutant removal efficiencies. Without these im-
provements, many of today's achievements in wa-
ter pollution control will be overwhelmed by
tomorrow's demand from urban population
growth. A recent report by the Water Infrastruc-
ture Network (WIN, 2000) also documents the
risk of reversing the environmental gains of the
last three decades.
Although POTWs are often the dominant
source of BOD effluent loading in major urban
areas, other sources affect waterways on a na-
tional scale. To put POTW effluent loading in
perspective, USEPA's National Water Pollution
Control Assessment Model (NWPCAM) and
input data from USEPA's Permit Compliance
System (PCS) and the Clean Water Needs Sur-
vey (CWNS) were used to examine current
BOD5 loading (ca. 1995) for several key point
and nonpoint sources (Bondelid et al., 1999).
From a national perspective, it was found that
currently (ca. 1995) POTW BOD5 loadings ac-
count for only about 38 percent of total point
source loadings and only 21 percent of total
loadings (point and nonpoint). Industrial fa-
cilities (major and minor) currently account for
about 62 percent of total point source BOD?
loadings and 34 percent of total BOD5 load-
ings. Clearly, continued improvement in the
water quality conditions of the Nation's water-
ways will require an integrated strategy to ad-
dress all pollutant sources, including both point
and nonpoint sources.
The first leg of the three-legged stool approach
focused on the Nation's investment in building
and upgrading POTWs to achieve at least sec-
ondary treatment. Based on this historical BOD
., .- - ,,„ — „ -,_——„-,„,„,,—, Figure !
Percent changes in population served, influent BOD loading
and effluent BOD5 and BODL loading before and after thi
1972 CWA (1968 to 1996). (Data from U.S. Public Hea/ti
Service municipal wastewater inventories; USEPA Cleat
Water Needs Surveys; USDOI, 1970; USEPA, 1997.
50-r-
I
o
i
c
co
o>
c
CO
.c
O
c
0)
0)
Q.
25
-25--
-50
Population -
Served
35%
Influent
Load
35%
BOD5
and
BODy
Effluent
Load
-45%
Effluent
Load
-23%
BODS
loading analysis, it is clear that the CWA's
mandate for secondary treatment as the
minimum acceptable treatment technol-
ogy, supplemented by more stringent wa-
ter quality-based effluent controls on a site-
specific basis, combined with financial as-
sistance from the Construction Grants and
CWSRF Programs, resulted in a dramatic
nationwide decrease in effluent loading of
BOD from POTWs into the Nation's wa-
terways (see Figure 5).
The 45 percent nationwide reduction in
effluent BOD? loading and the 23 percent
reduction in effluent BODU loading was
achieved during a period when total popu-
lation served and influent loading of BOD
both increased by 35 percent!
Conclusion
of the first leg
of the stool
There was a dramatic
nationwide decrease in
BOD effluent loading
from POTWs after the
1972 CWA despite a
significant increase in
population served!
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ES-7
-------
A systematic, peer-
reviewed approach was
developed to identify water
quality station records that
encode the "signal" related
to the water quality
impact of point source
discharges from the "noise"
of millions of historical
records archived in
STORET.
The Second Leg: An
examination of "worst-
case" DO in waterways
below point sources before
and after the CWA
The second leg follows up on the first leg with
the question Has the CWA'spush to reduce BOD
loading resulted in improved water quality in the
Nations waterways? And, if so, to what extent?
The key phrase in the question is "to what ex-
tent?" Earlier studies by Smith et al. (1987a,
1987b) and Knopman and Smith (1993) con-
clude that any improvements in DO conditions
in the Nation's waterways are detectable only
within relatively local spatial scales downstream
of wastewater discharges.
Because of the ecological significance of DO and
its well-known causal relationship with the de-
composition of organic carbon (car-
bonaceous BOD) and the decompo-
sition of organic nitrogen and ammo-
nia (nitrogenous BOD) from waste-
water discharges, historical DO
records provide an excellent environ-
mental indicator for characterizing
water quality responses to long-term
changes in wastewater loading. A con-
siderable amount of historical data is
archived, and readily accessible, in
STORET, USEPA's national water
quality database.
The inherent difficulty in evaluating
the effectiveness of reductions in point
source loading is the need to isolate
the water quality impact of discharges from the
impacts caused by other confounding factors
such as nonpoint sources, as well as the natural
influence of streamfiow and water temperature.
In this assessment, a systematic, peer-reviewed
approach has been designed to identity water
quality station records that encode the "signal"
related to the water quality impact of point
source discharges from the overwhelming
"noise" of millions of historical records archived
in STORET.
With DO as the key water quality indicator, and
keeping in mind the need to evaluate the change
in the DO "signal" over time (before and after
CWA) as well as over different spatial scales (i.e.,
river reaches [which average 10 miles in length],
catalog units, and major river basins), the fol-
lowing "rules" for data analysis were used in a
six-step data mining process to create before -
and after-CWA data sets of "worst case" DO to
be used in an unbiased comparison analysis of
downstream water quality conditions. The
screening rules associated with each phase are
listed below:
Step 1—Data Selection Rules
• DO data were extracted only for
summer (July-September).
• Only surface DO data (within 2 meters
of the surface) were used.
Step 2—Data Aggregation Rules From a
Temporal Perspective
• 1961-1965 served as the "time-block" to
represent persistent dry weather before
the CWA, and 1986-1990 served as the
time-block to represent persistent dry
weather after the CWA. These time-
blocks were selected based on an
analysis of long-term mean summer
streamfiow.
• DO data must come from a station in a
catalog unit that had at least 1 dry year
out of the 5 years in each before- and
after-CWA time-block.
ES-8
Executive Summary
-------
Step 3—Calculation of the Worst-case
DO Summary Statistic Rules
* For each water quality station, the 1 Oth
percentile of the DO data distribution
from the before-CWA time period (July
through September, 1961-1965) and the
1 Oth percentile of the DO data distribu-
tion from the after-CWA time period
(July through September, 1986-1990)
were used as the DO "worst-case"
statistic for the comparison analysis.
• A station must have a minimum of
eight DO measurements within each of
the 5-year time-blocks.
Step 4—Spatial Assessment Rules
* Only water quality stations on streams
and rivers affected by point sources were
included in the before- and after-CWA
comparison analysis. Stations affected
only by nonpoint sources were ex-
cluded. Out of 64,902 river reaches in
the contiguous United States, 12,476
are downstream of a point source. Also,
out of 2,111 catalog units, 1,666 have
river reaches that are downstream of a
point source.
Step 5—Data Aggregation Rules From a
Spatial Perspective
• For each data set and time-block, the
1 Oth percentile value from each eligible
station was aggregated within the spatial
hydrologic unit. (Since the scales are
hierarchical, a station's summary
statistic was effectively assigned to a
reach and a catalog unit.) A summary
statistic was then calculated and as-
signed to the spatial unit for the
purpose of characterizing its worst-case
DO. If a spatial unit had only one
monitoring station within its borders
meeting the screening criteria, the 10th
percentile DO value from that station
simply served as the unit's worst-case
summary statistic. If, however, there
were two or more stations within a
spatial unit's borders, the 10th percen-
tile values for all the eligible stations
were averaged, and this value used to
characterize worst-case DO for the unit.
Step 6—Development of the Paired
Data Sets (at each spatial scale)
• To be eligible for the paired (before vs.
after) comparison analysis, a hydrologic
unit must have both a before-CWA and
an after-CWA summary statistic
assigned to it.
The comparative before- and after-CWA analy-
sis of worst-case DO data derived using the
screening criteria described above and aggregated
by three scales of spatial hydrologic units (reach,
catalog unit, and major river basin) yielded the
following results.
Only water quality
stations on streams
and rivers affected by
point sources were
included in the before-
and after-CWA
comparison analysis.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ES-S
-------
Reach Scale Analysis
• 69 percent of the reaches evaluated showed
improvements in worst-case DO after the
CWA (311 reaches [out of a possible
12,476 downstream of point sources]
survived the data screening process with
comparable before- and after-CWA DO
summary statistics. The number of
reaches available for the paired analysis
was limited by the historical data
archived for the 1961-1965 period).
• These 311 evaluated reaches represent
a disproportionately high amount of
urban/industrial population centers,
with approximately 13.7 million
people represented (7.2 percent of the
total population served by POTWs in
1996). As shown in Figure 6, the top 25
improving reaches saw their worst-case
DO concentrations increase by 4.1 to
7.2 mg/L!
The number of evaluated reaches
characterized by worst-case DO below
5 mg/L was reduced from 167 to 97
(from 54 to 31 percent).
The number of evaluated reaches
characterized by worst-case DO above
5 rng/L increased from 144 to 214
(from 46 to 69 percent).
Key finding at the
reach scale: 69
percent of the paired
reaches showed
worst-case DO
improvements after
the CWA!
ES-10
Executive Summary
-------
i
f
a'
Before the CWA
After the CWA
0.0
12345678 910111213141516171819202122232425
River Reach Ranking
M
rn
c/i
Figure 6
Location map and distribution chart of the 25 RFl reaches identified with greatest after-CWA improvements in
10th percentlle DO, 1961-1965 vs. 1986-1990. Reaches are ranked by greatest before- and after-CWA improvements.
-------
Key finding at the
catalog unit scale: 68
percent of the paired
catalog units showed
worst-case DO
improvements after
the CWA!
Catalog Unit Scale Analysis
• 68 percent of the catalog units evaluated
showed improvements in worst-case DO
after the CWA (246 catalog units [out of
a possible 1,666 downstream of point
sources] survived the data screening
process with comparable before- and
after-CWA DO summary statistics).
• The number of evaluated catalog units
characterized by worst-case DO below
5 mg/L was reduced from 115 to 65
(from 47 to 26 percent). The number of
evaluated catalog units characterized by
worst-case DO above 5 mg/L increased
from 131 to 181 (from 53 to 74 per-
cent).
As shown in Figure 7, 53 of the 167
improving catalog units (32 percent)
improved by 2 mg/L or more while only
10 of 79 degrading catalog units (13
percent) degraded by 2 mg/L or more.
These 246 evaluated catalog units
represent a disproportionately high
amount of urban/industrial population
centers (see Figure 8), with approxi-
mately 61.6 million people represented
(32.5 percent of the total population
served by POTWs in 1996).
Figure 7 - -.—,..„ , , .,
Frequency distribution of the mean 10th percentlle DO for 246 catalog units that
improved (n = 167) and degraded (n = 79) after the CWA. (Source: USEPA STORET.)
O)
o
re
<->
to
O
c
Q.
O
O)
(0
4->
0)
2
V
0.
(n) = number of catalog units
7 to 8 6 to 7 5 to 6 4 to 5 3 to 4 2 to 3 1to2 Oto1
(a)
Magnitude of Decrease in
Worst-Case DO (mg/L) after the CWA
Oto1 1to2 2to3 3to4 4to5 5to6 6to7 7to8
(b)
Magnitude of Increase in
Worst-Case DO (mg/L) after the CWA
ES-12
Executive Summary
-------
I
a
Before the CWA
After the CWA
34567
Catalog Unit Ranking
Catalog units with improved 10th percentile DO
Catalog units with degraded 10th percentile DO
Figure 8
Location map of the 246 catalog units that improved or degraded in terms of 10th percentile DO after the CWA, 1961-1965 vs. 1986-
1990. The 10 catalog units with the greatest after-CWA improvements are highlighted and presented in a distribution chart.
(Source: USEPA STORET.)
-------
Major River Basin Scale Analysis
• A total of 11 out of 18 major river
basins had sufficient reach-aggregated
worst-case DO data for a before- and
after-CWA comparison.
• Based on two statistical tests, 8 of these 11
major river basins can be characterized as
having statistically significant improve-
ment in worst-case DO Levels after the
CWA! The three basins that did not
statistically improve under either test
also did not have statistically significant
degradation (Table 1).
When all the 311 paired (i.e., before vs.
after) reaches were aggregated and the
statistical tests run on the contiguous
states as a national whole, worst-case
DO also showed significant improve-
ment.
Key finding at the
hydrologic region scale:
8 of the 11 major river
basins with sufficient data
had statistically significant
improvement in worst-case
DO levels after the CWA!
Table 1: Statistical Significance of Trends in Mean 10th Percentile (Worst-Case)
Before vs. After the CWA (1961-1965 vs. 1986-1990)
River Basin
All USA (01-18)
01 - New England Basin
02 - Middle Atlantic Basin
03 - South Atlantic-Gulf
04 - Great Lakes Basin
05 - Ohio River Basin
06 - Tennessee River Basin
07 - Upper Mississippi Basin
08 - Lower Mississippi Basin
09 - Souris-Red Rainy Basin
10 - Missouri River Basin
11 - Arkansas-Red — White Basin
12 - Texas-Gulf Basin
13 - Rio Grande Basin
14 - Upper Colorado River Basin
15 - Lower Colorado River Basin
16 - Great Basin
17 - Pacific Northwest Basin
18 - California Basin
Paired t-test: 95% confidence - 2-sidec
Insufficient data for analysis
No. of Paired
(before vs. after)
Reaches
311
1
17
61
26
66
19
48
25
2
10
7
2
0
1
0
2
17
7
. (Source:
Paired
t-test
Yes
*
Yes
Yes
Yes
Yes
Yes
Yes
No
*
No
No
*
*
*
*
*
Yes
Yes
USEPA STOREI)
Kolmogorov
Smirnov
test
Yes
*
Yes
Yes
Yes
Yes
No
Yes
No
*
No
No
*
*
*
*
*
No
Yes
test. Kolmogorov Smirnov test: 90% confidence, 2-sided
DO by Major River Basin
Worst-
Case DO
(mg/L)
1961-65
4.56
4.30
2.80
4.10
3.85
5.40
4.08
3.80
3.79
5.65
5.76
5.36
5.77
-
4.88
-
7.45
7.61
5.61
test
Worst-
Case DO
(mg/L)
1986-90
5.53
6.90
4.94
4.73
6.06
6.04
5.23
5.31
3.94
6.75
6.53
4.60
4.37
-
7.22
--
6.10
8.21
7.58
ES-14
Executive Summary
-------
The second leg of the three-legged stool ap-
proach focused on assessing the change in the
point source discharge/downstream worst-case
DO signal over progressively larger spatial scales.
The results of this analysis show that there were
significant after-CWA improvements in worst-
case summer DO conditions in two-thirds of
the hydrologic units at all three spatial data ag-
gregation scales, from the small subwatersheds
of Reach File Version 1 river reaches (mean
drainage area of 115 mi2) to the very large wa-
tersheds of major river basins (mean area of
434,759 mi2).
These results provide strong evidence that the
CWA's requirements for municipal wastewater
treatment using secondary treatment as the
minimum acceptable technology, supplemented
by more stringent water quality-based effluent
controls on a site-specific basis, yielded broad
as well as localized benefits!
Conclusion of
the second leg
of the stool
There were significant
after-CWA improvements
in worst-case summer DO
conditions in two-thirds
of the hydrologic units at
all three spatial scales!
The Third Leg: Case
Study Assessments of
Water Quality
The national-scale evaluation of long-term
trends in water quality conditions associated
with the second leg of the three-legged stool
identified numerous waterways characterized
by substantial improvements in DO after the
CWA. The uniqueness of each waterway and
the activities surrounding it requires an inves-
tigation to go beyond STORET to identify,
quantify, and document in detail the specific
actions that have resulted in water quality im-
provements and associated benefits to water
resource users.
Nine urban waterways were selected for closer
examination of the factors that caused improve-
ment in local water quality and environmental
resources (Figure 9). Note that the case study
site selection was made prior to completion of
the DO trend analysis described in the second
study leg.
Most of the case study waterways were sites
of interstate enforcement cases from 1957 to
1972, were listed as potential waterways to con-
vene state-federal enforcement conferences in
1963, or were subjects of water quality evalua-
tion reports prepared for the National Com-
mission on Water Quality. Two sites (Ohio
River and tributaries to the Hudson-Raritan
estuary) were on a 1970 list of the top 10 most
polluted rivers. Yet, interestingly, these case
study waterways included none of the 25 river
reaches with the greatest before- versus after-
CWA improvements in DO found in the sec-
ond leg of this study (see Figure 6).
These case study waterways represent heavily ur-
banized areas with historically documented wa-
ter pollution problems. A variety of data sources,
including the scientific literature, USEPA's na-
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
-------
Figure 9 —- - -
Location map of case study waterways and distribution chart of their before- and after-CWA mean 10th
percentile DO for case study RF1 reaches: 1961-1970 vs. 1986-1995. (Source: USEPA STORET.)
2. Hudson-Rantan
estuary
3. Delaware estuary
1. Connecticut River
9. Willamette River
4. Potomac estuary
8. Upper Mississippi River
6. Chattahoochee River
Before the CWA
After the CWA
234567
Case Study Waterway Number
tional water quality database, and federal, state,
and local agency reports, were used to character-
ize long-term trends in population, point source
effluent loading rates, ambient water quality, en-
vironmental resources, and recreational uses. Ad-
ditional information was obtained from validated
water quality models for the Delaware, Potomac,
and James estuaries and Upper Mississippi River
case studies to quantify the water quality improve-
ments achieved by upgrading municipal facili-
ties to secondary and greater levels of treatment
as mandated by the 1972 CWA.
ES-16
Executive Summary
-------
Key findings from the nine case studies are high-
lighted below.
• In each of the case study urban areas,
significant investments were made in
expansions and upgrades to POTWs
with commensurate increases in popula-
tion served.
• Before the CWA, during the 10-year
period from 1961 to 1970, "worst-case"
DO levels fell in the range of 1 to
4 mg/L for most of the case study sites;
after the CWA, during the 10-year
period from 1986 to 1995, worst-case
DO levels improved to levels of almost
5 to 8 mg/L.
• Water quality improvements associated
with BOD5, suspended solids, coliform
bacteria, heavy metals, nutrients, and
algal biomass have been linked to
reductions in municipal and industrial
point source loads for many of the case
study waterways.
• Tremendous progress has been made in
improving water quality, restoring
valuable fisheries and other biological
resources, and creating extensive water-
based recreational opportunities (an-
gling, hunting, boating, bird-watching,
etc.) in all case study waterways.
The results of the third leg of the three-legged
stool approach revealed that the significant in-
vestments made in municipal wastewater treat-
ment resulted in dramatic improvements in re-
storing water quality and biological resources and
in supporting thriving water-based recreational
uses in all the case study areas.
Although significant progress has been achieved
in eliminating noxious water pollution condi-
tions, remaining problems with nutrient enrich-
ment, sediment contamination, heavy metals,
and toxic organic chemicals continue to pose
threats to human health and aquatic organisms
for these case study waterways. Serious ecologi-
cal problems remain to be solved for many of the
Nation's waterways, including the sites of these
case studies.
Conclusion of
the third leg
of the stool
Tremendous progress
has been achieved in
improving water quality,
restoring valuable
biological resources,
and creating recre-
ational opportunities in
all the case study areas!
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ES-17
-------
Conclusion
The three-legged stool approach to answering
the question Has the Clean Water Act's regula-
tion ofwastewater treatment processes at POTWs
been a success? was developed
so that each of the legs could
provide cumulative support
regarding the success or fail-
ure of the CWA-mandated
POTW upgrades to at least
secondary treatment. Exam-
ining the results of each of
the study legs, the conclu-
sion is overwhelming that
the stool does indeed "stand
up"!
Conclusion of
the three-legged
stool approach
At both broad and local
scales, the water pollution
control policy decisions
of the 1972 CWA have
achieved significant suc-
cesses nationwide in terms
of reduction of effluent
BOD from POTWs,
worst-case (summertime,
low-flow) DO improve-
ment in waterways, and overall water quality
improvements in urban case study areas.
Each leg of the stool
cumulatively and quantita-
tively supports the theory
that the 1972 CWA's regula-
tion of wastewater treat-
ment processes at POTWs
has been a significant
success!
long-term trends in signals for water quality
parameters other than DO (e.g., suspended
solids, nutrients, toxic chemicals, pathogens) to
develop new performance
measures to track the effec-
tiveness of watershed-based
point source and nonpoint
source controls.
As new monitoring data are
collected, it is crucial for the
success of future perfor-
mance measure evaluations
of pollution control policies
that the data be submitted,
with appropriate QA/QC
safeguards, to accessible
databases. If the millions
of records archived in
STORET had not been
readily accessible, it would
have been impossible to
conduct this national analy-
sis of DO changes over the
last quarter century.
Manu challenges
remain. We must maintain
and enhance the progress alreadq
i i - -'- T
achieved in municipal wastewater
pollution control as well as address
other pollution sources and problems
in the Nation's waterways.
The data mining and statisti-
cal methodologies de-
signed for this study
can potentially be
used to detect
Importantly, this study
provides the first national-scale comprehensive
evaluation of the effectiveness of the CWA's
technology- and water quality-based effluent
control policies in achieving the "fishable and
swimmable" goals of the act. Population
growth and expansion of urban development,
however, threaten to erase these achievements
unless improvement in wastewater treatment
and pollution control continues.
With the newer watershed-based strategies
for managing pollutant loading from point
and nonpoint sources detailed in USEPA's
Clean Water Action Plan (USEPA, 1998),
the Nation's state-local-private partner-
ships will continue to work to attain the
original "fishable and swimmable" goals
of the 1972 CWA for all surface waters
of the United States.
ES-18
Executive Summary
-------
REFERENCES
Adler, R.W., J.C. Landman, and D.M. Cameron.
1993. The Clean Water Act: 20 Years Later. Is-
land Press, Washington, DC.
Bondelid.T., C. Griffiths, andG. van Houten. 1999.
A National Water Pollution Control Assessment
Model. Draft tech. report prepared by RTI, Re-
search Triangle Park, NC, for U.S. Environmen-
tal Protection Agency, Office of Science & Tech-
nology, Washington, DC.
Chase, N. 1995. A river reborn. Letter to the Editor,
Washington Post, Washington, DC. January, 15.
GAO. 1986. Water Quality: An Evaluation Method
for the Construction Grants Program-Case Stud-
ies. Report to the Administrator, U.S. General
Accounting Office, Program, Evaluation and
Methodology Division, U.S. Environmental
Protection Agency, Washington, DC. Vol. 1,
GAO/PMED-87-4B. December.
Isaac, R.A. 1991. POTW improvements raise wa-
ter quality. Water Env. & Tech. June, pp. 69-72.
Knopman, D.S., and R.A. Smith. 1993. Twenty
Years of the Clean Water Act: Has U.S. Water
Quality Improved? Environment 35(1): 17-41.
Mearns, A. 1995. "Ready..Shoot...Aim! The Future
of Water." Editorial. WEF Water Env. Res.
67(7): 1019.
Patrick, R., F. Douglass, D.M. Palavage, and P.M.
Stewart. 1992. Surface Water Quality: Have the
Laws Been Successful? Princeton University Press,
Princeton, NJ. July.
Smith, RA, R.B. Alexander, and M.G. Wolman. 1987a.
Analysis and Interpretation of Water Quality Trends
m Major U.S. Rivers, 1974-81. Water-Supply Pa-
per 2307. U.S. Geological Survey, Reston, VA.
Smith, R.A., R.B. Alexander, and M.G. Wolman.
1987b. Water quality trends in the Nation's riv-
ers. Science 235 (27 March 1987):1607-1615.
Smith, R.A., R.B. Alexander, and K.J. Lanfear. 1992.
National Water Summary 1990-91. Stream Water
Quality: Stream Water Quality in the Contermi-
nous United States-Status and Trends of Selected
Indicators During the 1980s. USGS Water Sup-
ply Paper 2400, U.S. Geological Survey, Reston,
VA.
U.S. Bureau of the Census. 1996. Population pro-
jections of the United States by age, sex, race, and
Hispanic origin: 1995-2050. Current Population
Reports Series pp. 25-1130. Population Divi-
sion, U.S. Bureau of the Census, Washington,
DC.
USDOI. \970.MunicipalWasteFacilities in the'U.S.
Statistical Summary: 1968 Inventory. Federal Wa-
ter Quality Administration, U.S. Department
of the Interior, Washington, DC.
USEPA (STORET). STOrage and RETrieval Wa-
ter Quality Information System. Office of Wet-
lands, Oceans, and Watersheds, U.S. Environ-
mental Protection Agency, Washington, DC.
USEPA. 1974. National Water Quality Inventory,
1974305(b) Report to Congress. Vol. 1. EPA 440/
9-74-001. Office of Water Planning and Stan-
dards, U.S. Environmental Protection Agency,
Washington, DC.
USEPA. 1997. 1996. Clean Water Needs Survey, Con-
veyance, Treatment, and Control of Municipal
Wastewater, Combined Sewer Overflows and
Stormwater Runojf. Summaries of Technical Data.
Office of Water Program Operations, U.S. Envi-
ronmental Protection Agency, Washington, DC.
USEPA. 1998. Clean Water Action Plan: Restoring
and Protecting America's Waters. U.S. Environ-
mental Protection Agency, Washington, DC.
USEPA. 2000. Progress in Water Quality: An Evalu-
ation of the National Investment in Municipal
Wastewater Treatment. U.S. Environmental Pro-
tection Agency, Washington, DC.
WIN. 2000. Clean and Safe Water for the 21st Cen-
tury: A Renewed National Commitment to Water
andWastewater Infrastructure. Water Infrastructure
Network, Washington, DC. April.
Wolman, A. 1971. The Nation's Rivers. Science
174:905-917.
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
-------
ES-20 Executive Summary
-------
Chapter 1
Introduction
/ think there is no sense in forming an opinion
when there is no evidence to form it on. If you
build a person without any bones in him he may
look fair enough to the eye, but he will be
limber and cannot stand up; and I consider
that evidence is the bones of an opinion,
Mark Twain
in Personal Recollections of Joan of Arc
Today a student writing a paper on the Federal Water Pollution Control Act
Amendments of 1972 (Public Law 92-500, later to be known as the Clean
Water Act or CWA) would be hard-pressed to find a public official who
would say the legislation was not a success. Vice President Gore's remarks in
October 1997 celebrating the 25th anniversary of the act are representative of the
good feelings people have about the CWA (USEPA, 1997a; WEF, 1997).
In his speech the Vice President lauded the cooperative efforts of federal,
state, tribal, and local governments in implementing the act's pollution control
provisions. He reported that the quality of rivers, lakes, and bays has "improved
dramatically." He related success stories involving water-based commerce,
agriculture, tourism, fisheries, and quality of life for a variety of locations, includ-
ing Alaska's St. Paul Harbor, the Chesapeake Bay, Cleveland's Cuyahoga River,
the Long Island Sound, and the Houston Ship Channel. With cheers like that
ringing in people's ears, it's no wonder that the prevailing public opinion is one of
success. But what if the paper-writing student were to inquire skeptically about
the "bones" of this opinion? What scientific evidence could she cite to back up
this claim? Was the Nation indeed able to buy water quality success with the
approximately $200.6 billion in capital costs and $210.1 billion in operation
and maintenance costs (current year dollars) invested from 1972 to 1994 by
public and private authorities in point source water pollution control?
1 -1
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
A centerpiece of the CWA was a dramatic increase in federal support for
upgrading publicly owned treatment works (POTWs). From 1970 to 1999,
$77.2 billion in federal grants and contributions through the U.S. Environmental
Protection Agency's (USEPA's) Construction Grants and Clean Water State
Revolving Fund (CWSRF) programs was distributed to municipalities and states
for this activity. A 1995 editorial in the Water Environment Federation's research
journal noted that no comprehensive national study has ever been done to docu-
ment whether this investment has paid off in terms of improved water quality
(Mearns, 1995). Who could blame the student, then, if she applied Mark Twain's
logic and concluded that the public's opinion concerning the success of the CWA
was "limber" and could not "stand up."
The purpose of this study is to provide that student with the "bones" to form
an opinion that will stand up. Specifically, it was designed to examine whether
"significant" water quality improvements (in the form of increased dissolved
oxygen [DO] levels) have occurred downstream from POTW discharges since
the enactment of the CWA.
Background
The framers of the CWA, drawing on the experience of the Ohio River
Sanitation Commission, recognized that two basic sets of users depend on the
chemical, physical, and biological integrity of the Nation's waterways.
1. Water supply users, people who take delivery of and use water drawn
from various surface and ground water sources. Whether intentionally
or not, these users usually contaminate the water they receive with
pollutants such as organic matter, sediments, nutrients, pathogens, and
heavy metals. Contaminated water (wastewater) is then collected,
transported away from the site, treated, and returned back to a natural
waterbody, where it can be withdrawn and cycled again by the same or
another water supply system. Figure 1-1 illustrates this process, known
as the urban water cycle.
2. Water resource users, people such as fishermen, boaters, and swim-
mers who use water in its natural settings—lakes, streams, rivers, and
estuaries. This category might even be assumed to encompass the fish,
waterfowl, and other living things that depend on clean water to live,
reproduce, and thrive. These users can be directly affected by the
return flow of wastewater from water supply users.
Meeting the needs of water supply and water resource users has been a
problem that has vexed public officials for centuries. Only in the latter part of the
20th century did it become clear that the secret for keeping both sets of users
satisfied is to have all components of the cycle in place and functioning properly.
This fundamental concept played a pivotal role in the development of the CWA.
By the mid-1900s it was becoming more and more apparent that the weak
link in the urban water cycle was the wastewater treatment component. Many
communities were effectively short-circuiting the cycle by allowing raw or nearly
raw sewage to flow directly into lakes, streams, rivers, estuaries, and marine
waters. The organic matter contained in this effluent triggered increased growths
of bacteria and corresponding decreases in DO levels. This situation, in turn,
1 -2
-------
Chapter 1: Introduction
Figure 1-1
Simplified urban water
cycle.
Water supply
3.
Delivery
Water Supply
Side
1.
Water withdrawal
A
Wastewater
Disposal
Side
Water resource
Freshwater Sources
Lakes, Streams, and Estuaries
negatively affected the life functions offish, shellfish, and other aquatic organ-
isms. In addition, pathogens, nutrients, and other pollutants present in wastewater
made body contact unsafe, increased the growth of algae and rooted aquatic
plants, and reduced the potential for recreation and other uses. In sum, this weak
link in the urban water cycle was greatly affecting the lives and livelihoods of
water resource users downstream from POTWs.
Through the 1972 CWA, Congress aimed to remedy this situation by estab-
lishing a national policy requiring secondary treatment of municipal wastewater
as the minimum acceptable technology, supplemented by more stringent water
quality-based effluent controls on a site-specific, as-needed basis. At that time
approximately 4,859 systems in the country serving 56.8 million people were
providing only raw discharge or primary treatment of wastewater, a method that
uses physical processes of gravitational settling to separate settleable and float-
able solids from raw sewage. Secondary treatment, in contrast, yields a much
cleaner effluent because it uses biological processes to break down much of the
organic matter contained in the wastewater before allowing the wastewater to
leave the facility.
1 -3
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Between 1970 and 1995 a total of $61.1 billion (in current year dollars,
equivalent to $96.5 billion as constant 1995 dollars) was allocated by Congress
through USEPA's Construction Grants Program for the purpose of building new,
and upgrading old, POTWs. An additional $16.1 billion in federal contributions
was also distributed to states through the CWSRF from 1988 through 1999. In
addition to this federal expenditure, state and local governments and private
industry made significant investments to comply with regulations of the CWA and
other state and local environmental legislation. On a nationwide basis, actual
expenditure data compiled by the U.S. Department of Commerce, Bureau of
Economic Analysis, in the annual Pollution Abatement Cost Expenditures
documents a cumulative public and private sector capital expenditure of approxi-
mately $200.6 billion and an additional $210.1 billion as operating expenditures
(current year dollars) for water pollution control activities during the period from
1972 through 1994 (Vogan, 1996). In this context, the Construction Grants Pro-
gram provided federal grant support to local municipalities that amounted to
almost one-half of the public sector costs and about one-third of the total public
and private sector capital investment for water pollution control.
Study Approach
For years, members of Congress, as well as citizens and special interest,
environmental, and business groups, have been quizzing the USEPA about the
benefits gained from the Nation's extraordinary public and private investment in
wastewater treatment (GAO, 1986a, 1986b, 1986c; USEPA, 1988). Addressing
their questions is a difficult task because environmental systems are very com-
plex—so complex, in fact, that researchers can't even agree what "stick" to use
to measure success. Consequently, a number of tools have been applied in an
attempt to measure the success of water pollution control efforts. These include
• Reporting the number of discharge permits issued, enforcement actions
taken, and other administrative actions and programmatic evaluations
(Adler et al., 1993).
• Reporting on the number of POTWs built or upgraded, population
served by various treatment levels, effluent loading rates, and other
trends in the construction and use of wastewater infrastructure
(USEPA, 1997b).
• Inventorying state and national waterways meeting designated uses
(e.g., reports prepared by states to comply with CWA section 305(b),
USEPA's 305(b) summary reports to Congress) (ASIWPCA, 1984;
USEPA, 1995a, 1995b).
• Investigating changes in specific waterways following wastewater
treatment plant upgrades (GAO, 1978, 1986c; Leo et al., 1984; Patrick
et al., 1992).
• Investigating the statistical significance of national-scale changes in
water quality following the 1972 CWA (GAO, 1981; Knopman and
Smith, 1993; Smith etal., 1987a, 1987b).
1 -4
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Chapter 1: Introduction
Although each of the above approaches provides some evidence of the
accomplishments of municipal wastewater treatment under the CWA, none could
be considered a comprehensive assessment of national progress in meeting the
CWA's main goal of maintaining, or restoring, fishable and swimmable waters.
Clearly, a fresh measuring stick is needed—one that is simple enough to provide
nonscientists with evidence of the overall success or failure of the act, yet
rigorous enough to stand up to the scrutiny of people who make their living
analyzing water quality data trends.
This study takes a unique, three-pronged approach for answering the prima
facie question—Has the Clean Water Act's regulation of wastewater treatment
processes at POTWs been a success? Or posed more directly, How have the
Nation's water quality conditions changed since implementation of the 1972
CWA's mandate for secondary treatment as the minimum acceptable technol-
ogy for POTWs? The three-pronged approach described below was developed
so that each study phase could provide cumulative support regarding the success,
or failure, of the CWA-mandated POTW upgrades to at least secondary treat-
ment. Using the analogy of a three-legged stool, the study authors believed that
each leg must contribute support to the premise of CWA success. If one or more
legs fail in this objective, the stool will, in the words of Mark Twain, be "limber"
and unable to "stand up."
The First Leg:
An Examination of BOD
Loadings Before and After
the CWA (Chapter 2)
Biochemical oxygen demand (BOD) is a measurement that allows scientists
to compare the relative polluting strength of different organic substances. The
widest application of the BOD test, however, is for measuring waste load concen-
trations to (influent load) and discharged from (effluent load) POTWs and other
facilities and evaluating the BOD-removal efficiency of these treatment systems.
From 1970 to 1999, $77.2 billion (as current year dollars) in federal grants and
contributions through USEPA's Construction Grants and CWSRF programs was
distributed to municipalities and states to upgrade POTWs and, among other
objectives, to increase their BOD-removal efficiency. Did this investment pay
off in terms of decreasing BOD effluent loadings to the Nation's waterways?
The purpose of the first leg of this study is to examine nationwide trends in both
influent and effluent BOD loadings before and after the CWA.
Chapter 2 begins with some background discussions to help the reader
better understand the significance of the wastewater component of the urban
water cycle and the pivotal role the 1972 CWA played in establishing the national
policy requiring secondary treatment as the minimum acceptable technology for
this component. Specifically, Sections A and B trace some historical conse-
quences of not incorporating the wastewater treatment component of the urban
water cycle. Beginning with ancient Athenians and moving through time, societies
around the world suffered the results of releasing raw or inadequately treated
sewage into waterways, including outbreaks of disease and the destruction of
This study takes a
unique three-pronged
approach to evaluate
in water quality
conditions since
the enactment of
the 1072 CWA.
1 -5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
fragile aquatic ecosystems. Sparked by the Lawrence (Massachusetts) Experi-
ment Station's discovery of the trickling filter method in 1892 and the development
of the BOD test in the 1920s, many states subsequently adopted water quality
standards and encouraged the use of secondary treatment for the purpose of
protecting their waterways and water supply and water resource users. Unfortu-
nately, rapidly growing urban populations and uneven applications of wastewater
treatment funding and technology caused conditions to deteriorate in many highly
populated watersheds in the first two-thirds of the 20th century. Section C of this
chapter traces the evolution of the federal government's role in water pollution
control during this time period. Key legislation is highlighted to document its
movement from passive advisor through to the passage of the 1972 CWA, the
decisive legislation that transferred authority for directing and defining water
pollution control policy and initiatives from the states to USEPA. Post-1972
legislation and regulations continue to refine water pollution control goals and
objectives and authorize the funding and policies necessary to meet them.
Twenty-five years after the passage of the CWA, the number of people
served by POTWs has increased from about 140 million in 1968 to 189.7 million in
1996. In spite of this population increase (and corresponding increases in
the amount of BOD flowing into these facilities), has there been a significant
decline in BOD loading to the Nation's waterways ? Section D examines
trends in influent and effluent BOD loading from 1940 to 1996 based on popula-
tion served and BOD removal rates associated with various treatment levels.
Section E helps put POTW effluent BOD loading into national perspective
by examining rates and spatial distribution of BOD loadings associated with other
point and nonpoint sources of BOD in addition to municipal loadings. Using
USEPA's National Water Pollution Control Assessment Model (NWPCAM)
(Bondelid et al., 1999), loading estimates were derived for urban and rural runoff,
combined sewer overflows, and industrial wastewater discharges, in addition to
municipal discharges. Comparison of these sources at a national level provides
insight on how total BOD loading is distributed among sources in various regions
of the United States. Section F presents a discussion of the investment costs
associated with water pollution control infrastructure over the time period 1970 to
1999 and summarizes projections of future wastewater infrastructure needs into
the 21st century.
The Second Leg: An
Examination of "Worst-Case"
DO in Waterways Below
Point Sources Before and
After the CWA (Chapter 3)
Professionals in the water resource field use many different parameters to
characterize water quality. If one's interest centers on protecting fish and other
aquatic organisms, however, DO concentration is a key parameter to focus on.
This interest is articulated in section 101 of Title I of the Clean Water Act in the
1 -6
-------
Chapter 1: Introduction
Table 1-1. USEPA water quality criteria for dissolved oxygen concentration
Cold-water biota
Early life Other life
stages3" stages
Warm-water biota
Early life Other life
stages" stages
30-day mean
7-day mean
7-day mean minimum
1-day minimum"
NAC
9.5 (6.5)
NA
8.0 (5.0)
6.5
NA
5.0
4.0
NA
6.0
NA
5.0
5.5
NA
4.0
3.0
a Recommended water column concentrations to achieve the required intergravel dissolved
oxygen concentrations shown in parentheses. The figures in parentheses apply to species
that have early life stages exposed directly to the water column.
b Includes all embryonic and larval stages and all juvenile forms to 30 days following hatching.
0 NA—not applicable
d All minima should be considered instantaneous concentrations to be achieved at all times.
Further restrictions apply for highly manipulative discharges.
form of a national goal for fishable waters. Fish kills are the most visible symptom
of critically low levels of DO. Some species of fish can handle low levels of
oxygen better than others. Cold-water fish (salmon, trout) require higher DO
concentrations than warm-water fish (bass, catfish). Early life stages usually
require higher DO concentrations than adult stages. Table 1-1 presents USEPA's
water quality criteria for DO for cold-water and warm-water biota for four
temporal categories. The reader should note that a DO concentration of 5 mg/L
has been adopted in this study as a general benchmark threshold for defining
desirable versus undesirable levels of DO (i.e., the minimum concentration to be
achieved at all times for early life stages of warm-water biota).
The concentration of DO in a stream fluctuates according to many natural
factors, including water temperature, respiration by algae and other plants,
nitrification by autotrophic nitrifying bacteria, and atmospheric reaeration. By far
the biggest factor in determining DO levels in most waterbodies receiving waste-
water discharges, however, is the amount of organic matter being decomposed by
bacteria and fungi. Twenty-five years after the passage of the CWA, the Nation's
investment in upgrading POTWs to secondary or greater levels of treatment
resulted in significant reductions in BOD loadings. Has the CWA'spush to
reduce BOD loading resulted in improved water quality in the Nation's
waterways ?
The challenge in evaluating the effectiveness of point source BOD loading
reductions is the need to isolate their impacts on downstream DO from impacts
caused by urban stormwater runoff and rural nonpoint sources and the natural
seasonal influences of streamflow and water temperature. An innovative ap-
proach was developed to reduce these confounding factors and screen for water
quality station records that inherently contain a "signal" linking point source
discharges with downstream DO. It includes the following steps:
• Developing before- and after-CWA data sets of DO summary statistics
derived from monitoring stations that were screened for worst-case
conditions (i.e., conditions that inherently contain the sharpest signal).
1 -7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
• Assigning the worst-case DO summary statistic to each station for
each before- and after-CWA time period and then aggregating station
data at sequentially larger spatial scales.
• Conducting a "paired" analysis of spatial units that have both a before-
and an after-CWA worst-case DO summary statistic and then docu-
menting the direction (improvement or degradation) and magnitude of
the change.
• Assessing how the point source discharge/downstream worst-case DO
signal changes over progressively larger spatial scales.
The hierarchy of spatial scale plays an especially important role in this
second leg of the three-legged stool approach for examining water quality condi-
tions before and after the CWA. Three spatial scales are addressed in this portion
of the study: reach, catalog unit, and major river basin.
Reaches are segments of streams, rivers, lakes, estuaries, and coastlines
identified in USEPA's Reach File 1 (RF1). In this system, a reach is defined by
the confluence of a tributary upstream and a tributary downstream. Reaches in
RF1 average about 10 miles in length and have a mean drainage area of 115
square miles. Created in 1982, RF1 contains information for 64,902 reaches in the
48 contiguous states, covering 632,552 miles of streams. Figure 1-2 is a map of
the stream reach network in the Chesapeake Bay drainage area.
Figure 1-2
Reach File Version 1
stream reach network in
the Chesapeake Bay
drainage area.
1 -8
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Chapter 1: Introduction
An individual reach in the RF1 system is identified by an 11-digit number.
This number carries much spatial information. It identifies not only the reach
itself, but also the hierarchy of watersheds to which the reach belongs. The first
eight digits of the identification number are the hydrologic unit catalog (HUC)
code. Originally developed by the U.S. Geological Survey (USGS), the HUC code
identifies four scales of watershed hierarchy. The highest scale, coded in the first
two digits of the identification number, is the hydrologic region (commonly re-
ferred to a major river basin). Hydrologic regions represent the largest river
basins in the country (e.g., the Missouri River Basin and the Tennessee River
Basin). Subregions are identified by the next two numbers. These are followed by
the accounting unit and the cataloging unit, the smallest scale in the hierarchy.
Figures 1-3 and 1-4 display the 18 hydrologic regions and the 2,111 cataloging
units in the contiguous 48 states.
Figure 1-3
The 18 major river
basins (hydrologic
regions) of the
48 contiguous states.
Rio Grande River I T T^xas-Gulf
Figure 1-4
The 2,111 hydrologic
catalog units of the 48
contiguous states.
1 -9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 1-2. Station and reach identification codes: Reach File Version 1
(RF1)
Agency ID: 21 MINN
Station ID: MSU-815-BB15E58
Station Location: Mississippi R ©Lock & Dam#2 at Hastings
Major river basin name: Upper Mississippi River
Major river basin ID: 07
Subbasin ID: 0701
Accounting Unit ID: 070102
Catalog Unit ID: 07010206
Reach ID: 07010206001
Station milepoint on reach UM 815.5
Reach length (miles) 33.1
Upstream milepoint of reach (Minnesota R) UM 844.7
Downstream milepoint of reach (St. Croix R) UM 811.6
Developers of RF1 extended the 8-digit HUC code by three digits for the
purpose of identifying the reaches within the cataloging unit. Table 1-2 is an
example of the RF1 identification codes for a reach of the Upper Mississippi
River near Hastings, Minnesota. This 33.1-mile reach is defined by the
confluence of the Minnesota River (upstream) and the St. Croix River (down-
stream).
Many engineering studies have documented the impact of BOD loading on
the DO budget in reaches immediately below municipal outfalls. Consequently,
one would expect to find a sharp signal linking point source discharges with
worst-case DO in those reaches. The key aspect of this investigation, therefore,
was to see how the signal changed (or if it could be detected at all) as one
aggregated worst-case DO data at increasingly larger spatial scales and then
compared summary statistics associated with time periods before and after the
CWA. Detection of a statistically significant signal at the catalog unit and major
river basin scales would provide evidence that the CWA mandates to upgrade to
secondary treatment and greater levels of wastewater treatment yielded broad as
well as localized benefits.
Figure 1-5 illustrates signal and noise relationships over the range of spatial
scales (reach, catalog unit, and major river basin) using the Upper Mississippi
River near Hastings, Minnesota, as an example. The line graphs in the left side of
the figure display DO data collected at monitoring stations from 1953 to 1997
aggregated by spatial unit. The bar graphs on the right side of the figure compare
worst-case DO (mean 10th percentile) for designated time periods before and
after the CWA and are produced as the final step of the comparison analysis
process described in Chapter 3. The summary statistics they present are derived
from station data that have been selected, aggregated, and spatially assessed so
that they might have the best chance of inherently containing a "signal" linking
point source discharges with downstream DO.
1 -10
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Chapter 1: Introduction
Figure 1-5
Line graphs of DO observations for the Upper Mississippi River from 1953 to 1997 and bar charts of worst-case DO
before and after the CWA for (a) reach scale, (b) catalog unit scale, and (c) major river basin scale.
Source: USEPA STORET for (a) RF1 reach 07010206001 (UM 811.6-844.7), (b) catalog unit 07010206 (UM 811.6-
879.8), and (c) major river basin (07).
(a) Reach scale
25
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
(b) Catalog unit scale
25-r
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
(c) Major river basin scale
25
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
o
0)
25
4~ Benchmark
for determining
undesirable versus
desirable levels of
worst-case DO
234567
Worst-Case DO (mg/L)
o
0)
•§
m
4~ Benchmark
for determining
undesirable versus
desirable levels of
worst-case DO
234567
Worst-Case DO (mg/L)
I
o
£
38
4~ Benchmark
for determining
undesirable versus
desirable levels of
worst-case DO
234567
Worst-Case DO (mg/L)
1 -11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Examining the line graphs in Figure 1-5, one can see that each broader
spatial scale aggregation of station data yields a "noisier" data pattern. The bar
chart for the reach scale (the finest scale) displays the greatest improvement in
worst-case DO, increasing 3.5 mg/L from before to after the CWA. At the
broader scales, an improvement is detected, but it is not as large (a before and
after difference of 1.7 mg/L at the catalog unit scale and 1.5 mg/L at the major
river basin scale). This is because the larger spatial units contain stations both
near and far from point source outfalls. In spite of the unavoidable introduction of
data noise, however, the signal linking point source discharge to downstream DO
is still detectable at the broader scales using the data mining and statistical
methodology developed by the study authors. Readers should note that in this
example, the worst-case DO concentration was below the benchmark threshold
of 5.0 mg/L at all three scales before the CWA and above the threshold at all
three scales after the CWA.
Section A of Chapter 3 provides background on the relationship between
BOD loading and stream water quality and discusses the two key physical
conditions (high temperature and low flow) that create "worst case" conditions
for DO. Section B describes the development and application of a set of screen-
ing rules to select, aggregate, and spatially assess before- and after-CWA worst-
case DO data drawn from USEPA's STORET database. Section C presents the
results of the comparison analysis of worst-case DO from before and after the
CWA for reach, catalog unit, and major river basin scales.
The Third Leg:
Case Study Assessments
of Water Quality
(Chapters 4 through 13)
The second leg of this study focused on the use of large national databases
and statistical methods to examine temporal and spatial trends in DO conditions
nationwide. However, the uniqueness of each waterway and the activities sur-
rounding it requires an investigation to go beyond STORET to identify, quantify,
and document in detail the specific actions that have resulted in water quality
improvements and associated benefits to water resource users.
In the third and final leg of this study nine urban waterways have been
selected to characterize changes in population, point source effluent loading,
water quality, and environmental resources before and after the CWA:
• Connecticut River • Chattahoochee River
• Hudson-Raritan estuary • Ohio River
• Delaware estuary • Upper Mississippi River
• Potomac estuary • Willamette River
• James estuary
1 -12
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Chapter 1: Introduction
These waterways were selected to represent heavily urbanized areas with
historically documented water pollution problems. A variety of data sources,
including the scientific literature, USEPA's national water quality database
(STORET), and federal, state, and local agency reports, were used to character-
ize long-term trends in population, point source effluent loading rates, ambient
water quality, environmental resources, and recreational uses. Additional informa-
tion was obtained from validated water quality models for the Delaware,
Potomac, and James estuaries and Upper Mississippi River case studies to
quantify the water quality improvements achieved by upgrading municipal facili-
ties to secondary and better levels of treatment as mandated by the 1972 CWA.
Chapter 4 presents an overview of the case study assessment approach and
provides background on previous efforts that have used case studies to examine
long-term changes in water quality conditions in the United States. Chapter 4 also
summarizes the overall findings for the nine urban waterways; detailed assess-
ments are provided for each in Chapters 5 through 13.
The Audience For This Report
This study was designed with two broad groups in mind. The primary
audience are the technical scientists and engineers who try to understand and
evaluate cause-effect relationships of pollutants, their sources, and the fate of
these pollutants in receiving waters. Understanding these relationships is crucial
for developing appropriate (cost-effective and environmentally protective) pollu-
tion control measures. This same audience is often tasked with the responsibility
of developing and carrying out large-scale monitoring programs whose purpose is
to gage the performance of various policy decisions related to pollution source
control.
The secondary audience is Congress, regulatory/policy professionals, and
the informed public who have often questioned the effectiveness of major pollu-
tion control programs directed at the national level. It may benefit future decisions
makers to know if major public works programs (i.e., the CWA Construction
Grants and CWSRF programs) accomplished what they were designed to do—
namely reduce effluent BOD loads from municipal and industrial sources and
improve dissolved oxygen in many previously degraded waterways of the Nation.
These same groups also need to understand that water pollution control efforts
are never ending. The 1972 CWA did not "solve" the problem. In fact, waste
materials are generated continuously and effluent removal efficiencies must
increase in the future to compensate for population growth. Planning for O&M
expenditures as well as capital expenditures for replacement of obsolete facilities
and upgrades to maintain adequate levels/efficiency of wastewater removal is an
ongoing requirement. A projection analysis presented in Chapter 2 demonstrates
that many of the gains in national water quality improvements may be lost if
future wastewater infrastructure investments and capacity does not keep pace
with expected urban population growth.
1 -13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
References
Adler, R.W., J.C. Landman, and D.M. Cameron. 1993. The Clean Water Act: 20
years later. Island Press, Washington, DC.
ASIWPCA. 1984. America's clean water: The states' evaluation of progress
1972-1982. Executive Summary and Technical Appendix. Association of
State and Interstate Water Pollution Control Administrators, Washington, DC.
Bondelid, T., C. Griffiths, and G. Van Houten. 1999. A national water pollution
control assessment model. Draft technical report prepared by Research
Triangle Institute, Durham, NC, for U.S. Environmental Protection Agency,
Office of Science and Technology, Washington, DC.
GAO. 1978. Secondary treatment of municipal wastewater in the St. Louis
Area: Minimal impact expected. GAO/CED-78-76. U.S. General Accounting
Office, Program, Evaluation and Methodology Division, Washington, DC.
GAO. 1981. Better monitoring techniques are needed to assess the quality of
rivers and streams. Vol.#l. Report to Congress. GAO/CED-81-30. U.S.
General Accounting Office, Program, Evaluation and Methodology Division,
Washington, DC.
GAO. 1986a. The Nation's water: Key unanswered questions about the
quality of rivers and streams. Vol. 1. GAO/PMED-86-6. U.S. General
Accounting Office, Program, Evaluation and Methodology Division, Washing-
ton, DC.
GAO. 1986b. Water quality: An evaluation method for the Construction
Grants Program—methodology. Vol. 1. Report to the Administrator. GAO/
PMED-87-4A. U.S. General Accounting Office, Program, Evaluation and
Methodology Division, Washington, DC.
GAO. 1986c. Water quality: An evaluation method for the construction
grants program-case studies. Vol. 1. Report to the Administrator. GAO/
PMED-87-4B. U.S. General Accounting Office, Program, Evaluation and
Methodology Division, Washington, DC.
Knopman, D.S. and R.A. Smith. 1993. Twenty years of the Clean Water Act:
Has U.S. water quality improved? Environment 35(1):17-41.
Leo, W.M., R.V. Thomann, and T.W. Gallagher. 1984. Before and after case
studies: Comparisons of water quality following municipal treatment plant
improvements. EPA430/9-007. Technical report prepared by HydroQual, Inc.,
for U.S. Environmental Protection Agency, Office of Water Programs, Wash-
ington, DC.
Mearns, A. 1995. "Ready...shoot...aim! The future of water." Editorial. WEF
Water Env. Res. 67(7):1019.
Patrick, R., F. Douglass, D.M. Palavage, and P.M. Stewart. 1992. Surface water
quality: Have the laws been successful? Princeton University Press,
Princeton, NJ.
Smith, R.A., R.B. Alexander, and M.G. Wolman. 1987a. Analysis and interpre-
tation of water quality trends in major U.S. rivers, 1974-81. Water-Supply
Paper 2307. U.S. Geological Survey, Reston, VA.
Smith, R.A., R.B. Alexander, and M.G. Wolman. 1987b. Water quality trends in
the Nation's rivers. Science 235 (27 March 1987): 1607-1615.
1 -14
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Chapter 1: Introduction
USEPA. 1995a. National water quality inventory: 1994 report to Congress.
EPA841-R-95-005. U.S. Environmental Protection Agency, Office of Water,
Washington, DC.
USEPA. 1995b. National water quality inventory: 1994 report to Congress.
Appendices. EPA841-R-95-006. U.S. Environmental Protection Agency,
Office of Water, Washington, DC.
USEPA. 1997a. The Clean Water Act: A snapshot of progress in protecting
America's waters. Vice President Al Gore's remarks on the 25th Anniversary
of the CWA. U.S. Environmental Protection Agency, Washington, DC.
USEPA. 1997b. 7996 Clean Water Needs Survey: Conveyance, treatment,
and control of municipal wastewater, combined sewer overflows and
stormwater runoff. Summaries of technical data. U.S. Environmental
Protection Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1988. POTW's and water quality: In search of the big picture: A
status report on EPA's ability to address several questions of ongoing
importance to the Nation's municipal pollution control program. U.S.
Environmental Protection Agency, Office of Water, Office of Municipal
Pollution Control, Washington, DC.
Vogan, C.R. 1996. Pollution abatement and control expenditures, 1972-94.
Survey of current business. Vol. 76, No. 9, pp. 48-67. U.S. Dept. of Com-
merce, Bureau of Economic Analysis.
WEF. 1997. Profiles in water quality: Clear success, continued challenge.
Water Environment Federation, Alexandria, VA.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
1 -16
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Chapter 2
An Examination of BOD
Loadings Before and
After the CWA
Chapter 1 introduced the "three-legged stool" approach to assess the
success of the CWA's mandate for POTW upgrades to secondary and
greater than secondary wastewater treatment. The premise is that each
"leg" of the approach must provide cumulative support for the stool to stand up
firmly and success to be declared. Chapter 2 presents the results of the first leg.
Specifically, this chapter focuses on whether there was a significant reduction in
the discharge of oxygen-demanding materials from POTWs to the Nation's
waterways after implementation of the 1972 CWA.
To help put this analysis into perspective, Chapter 2 begins with a back-
ground discussion of the historical consequences of ignoring the wastewater
treatment component of the urban water cycle on the aquatic ecosystem
(Section A) and then explains how scientists and engineers eventually harnessed
the power of decomposers and developed the process now known as secondary
treatment (Section B). Section C traces the legislative and regulatory history of
the federal role in water pollution control and how the 1972 CWA accelerated the
national trend of upgrading POTWs to at least secondary treatment. Section D
presents national trends in influent BOD loading (BOD entering POTWs) and
effluent BOD loading (BOD discharged from POTWs into surface waters) for
select years between 1940 and 1996, as well as effluent loading projections into
the 21 st century.
During the mid-1990s (ca. 1995), pollutant loading from municipal wastewa-
ter treatment facilities accounted for only about one-fifth of the estimated total
national point and nonpoint source load of BOD discharged to surface waters.
Section E presents comparative estimates of the remaining four-fifths of the total
national load accounted for by industrial wastewater dischargers, combined sewer
overflows (CSOs), and nonpoint (rural and urban1) sources. Section F examines
the national public and private investment costs associated with water pollution
control. Section G provides a summary, conclusions, and a perspective on future
trends for municipal wastewater loads.
For the purposes of this comparison, urban "nonpoint" sources include areas within the National
Pollutant Discharge Elimination System (NPDES) stormwater permit program that meet the legal
definition of a "point" source in section 502(14) of the CWA.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
A. Historical Consequences of Ignoring
the Wastewater Treatment Component
of the Urban Water Cycle
The urban water cycle can be divided into a water supply side and a
wastewater disposal side (see Figure 1-1). The basic technological framework
for the water supply side began as far back as 5,000 years ago when people from
the Nippur of Sumeria, a region of the Middle East, built a centralized system to
deliver water into populated areas (Viessman and Hammer, 1985). The Minoans
at Knossos, some 1,000 years later, improved on the concept with the installation
of a system of cisterns and stone aqueducts designed to provide a continuous flow
of water from the surrounding hills to dwellings in the central city. Basic concepts
and instructions related to purity of water, cleanliness, and public sanitation are
also recorded in the books of Leviticus and Deuteronomy (23:12-13) in the Old
Testament. Talmudic public sanitation laws were enacted in Palestine to protect
water quality in the centuries before and after the early Christian era ca. 200
B.C. to 400 A.D. (Barzilay et al., 1999).
The ancient Athenians were some of the first people to develop the waste-
water disposal side of the urban water cycle. The Greeks moved sanitary wastes
away from their central city through a system of ditches to a rural collection
basin. The wastewater was then channeled through brick-lined conduits for
disposal onto orchards and agricultural fields. In the ancient world, though, the
Roman Empire attained the highest pinnacle for developing the knowledge and
technology to select the best water supplies and to construct far-reaching net-
works of aqueducts to bring water supplies to Rome for distribution through pipes
to wealthy homes and public fountains. The Romans also built large-scale public
sanitation projects for collecting and controlling sewage and stormwater drainage.
The great Roman sewer Cloaca Maximum still drains the Forum in Rome today
after 2,000 years of operation.
In expanding their empire throughout North Africa and Europe, the Romans
introduced the technologies needed to develop water supplies and to construct
aqueducts and urban drainage systems to promote rudimentary standards of
public sanitation. With the collapse of the Roman Empire, however, the public
sanitation infrastructure was neglected and the technology was lost and forgotten
for a thousand years as the "Dark Ages" descended on the western world. Filth,
garbage, excrement in the streets, polluted water sources, disease, plague, and
high mortality rates were common consequences of the dismal public sanitary
conditions that persisted well into the 19th century (Barzilay et al., 1999).
Throughout history, two components of the urban water cycle were absent:
wastewater treatment and the transport of treated wastewater for discharge back
to natural waterbodies. For towns situated near coastal areas, estuaries, or large
rivers, short-circuiting the cycle caused no immediate consequences because
these waterbodies had some capacity to assimilate raw sewage without causing
water pollution problems. For many inland communities, however, water pollution
problems were more acute. As populations increased, even coastal towns were
forced to reckon with the consequences of ignoring the wastewater treatment
component of the urban water cycle (see Rowland and Heid, 1976).
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Much of the blame for incomplete urban water cycles up until the middle of
the 19th century can be traced to a general ignorance about the consequences of
allowing untreated wastewater to flow into surface waters used for drinking
water downstream. As the relationship between this practice and its effects on
public health became better understood, however, a community's refusal to adopt
effective wastewater treatment in its cycle was more often based in politics and
economics, rather than a lack of technological knowledge (see Rowland and Heid,
1976). No matter the reason, bypassing the wastewater treatment side of the
urban water cycle affected both water supply and water resource users.
Impacts on Water Supply Users and "The Great
Sanitary Awakening"
The introduction of household piped water in the mid-19th century was the
key technological development that cemented the two sides of the urban water
cycle—water supply and wastewater disposal. Unfortunately, although piped
water supply systems gave urban dwellers more convenient access to water,
people were also held hostage to the water supply source chosen by the local
water company. For many city dwellers, drinking piped water became hazardous
to one's health as massive epidemics of waterborne diseases such as cholera and
typhoid fever broke out in many cities in Great Britain and the United States
(Table 2-1).
Table 2-1. Pathogens and their associated diseases. (Adapted from Metcalf and Eddy, 1991)
Pathogen
Disease
Effects
Bacteria
Escherichia coli
Legionella pneumophila
Leptospira sp.
Salmonella typhi
Salmonella sp.
Shigella sp.
Vibrio cholerae
Yersinia enterolitica
Gastroenteritis
Legionellosis
Leptospirosis
Typhoid fever
Salmonellosis
Shigellosis
Cholera
Yersinosis
Vomiting, diarrhea, death in susceptible populations
Acute respiratory illness
Jaundice, fever (Weil's disease)
High fever, diarrhea, ulceration of the small intestine
Diarrhea, dehydration
Bacillary dysentery
Heavy diarrhea, dehydration
Diarrhea
Protozoa
Balantidium coli
Cryptosporidium sp.
Entamoeba histolytica
Giardia lamblia
Naegleria fowleri
Balantidiasis
Cryptosporidiosis
Amedbiasis
Giardiasis
Amoebic
meningoencephalitis
Diarrhea, dysentery
Diarrhea
Diarrhea w/bleeding, abscesses on liver, small intestine
Mild to severe diarrhea, nausea, indigestion
Fatal disease; brain inflammation
Viruses
Adenovirus (31 types)
Enteroviruses (67 types)
Hepatitis A
Norwalk agent
Reovirus
Rotavirus
Respiratory disease
Gastroenteritis
Infectious hepatitis
Gastroenteritis
Gastroenteritis
Gastroenteritis
Heart anomalies, meningitis
Jaundice, fever
Vomiting, diarrhea
Vomiting, diarrhea
Vomiting, diarrhea
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Dr. John Snow, physician to England's Queen Victoria, was one of the first
to scientifically link waterborne diseases to contaminated source water supplies.
Examining records of some 14,600 Londoners who had died in an 1854 cholera
epidemic, Snow found that people who had received water from an intake
downstream of London's sewage outlets in the lower Thames River had a much
higher death rate (8.5 times higher) than those receiving Thames River water
from an intake upstream of the sewage discharges (Snow, 1936). The threat of
contaminated water sources did little, however, to quell the construction boom of
new water supply systems in the second half of the 19th century, especially in the
United States. In 1850 there were about 83 water systems in the United States.
By 1870, the count had risen to 243 systems (Fuhrman, 1984).
Like Londoners, American city dwellers with piped water faced an in-
creased risk of waterborne diseases. Beginning in 1805, the New York City
Council had the authority and responsibility for sanitary conditions in the city.
Despite this early recognition of governmental responsibility for public health,
epidemics of typhoid fever broke out in 1819, 1822,1823, and 1832 and cholera
ravaged workers on the Erie Canal (Rowland and Heid, 1976). Between 1832
and 1896, cities in North America and Europe suffered four devastating outbreaks
of cholera that were spread by polluted urban water supply systems (Garret!,
1994). Cholera epidemics in New York City in 1832 and 1849 claimed 3,500 and
5,000 lives, respectively. In 1891 typhoid fever caused the deaths of 2,000 people
in Chicago (Fair et al., 1971). Hundreds more succumbed to typhoid in Atlanta
and Pittsburgh in the 20-year period between 1890 and 1910 (Bulloch, 1989). The
importance of an unpolluted source water for public drinking water was clearly
shown in the earliest public health studies of waterborne diseases and drinking
water supplies. Typhoid death rates in 61 cities of the United States during 1902-
1906, for example, ranged from a high of 120 per 100,000 for a run-of-river
supply for Pittsburgh, Pennsylvania, to a low of 15 per 100,000 for the upland
watershed supply of New York City (Okun, 1996).
This trend would have certainly continued for a few more decades if not for
the discovery of a new purification technology: chlorination of drinking water. As
a disinfecting agent, chlorine gained widespread use in the years 1908-1911, soon
bringing typhoid fever and cholera outbreaks under control in virtually all commu-
nities that adopted chlorination. Detailed mortality records and public water supply
records compiled by the Commonwealth of Massachusetts, for example, clearly
illustrate the link between the introduction of filtration and disinfection of public
water supplies and the sharp reduction in typhoid fever deaths (Figure 2-1) from a
peak of 125 per 100,000 in 1860 to less than 5 per 100,000 by 1920 and essentially
zero from 1940 to the present time (Fair et al., 1971; J. Higgins, Massachusetts
DEP, personal communication, September 1998; USCB, 1975).
Influenced by the Enlightenment and democratic movements of the late 18th
century in Britain, France, and the new United States, the concept that a govern-
ment had the moral and ethical responsibility to protect the general welfare of its
citizens, including public health, arose in Britain and the United States during the
first half of the 19th century. Motivated by the bleak urban conditions chronicled
by Charles Dickens, Chadwick's (1842) Report on the Sanitary Condition of
the Labouring Population of Great Britain marked the beginning of the "Great
Sanitary Awakening" (Okun, 1996). Chadwick's report directly influenced
passage of Great Britain's Public Health Act of 1848 and its formation of the
2-4
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Typhoid deaths
% of population
served by public
water suppliers
1940
1960
TJ
(D
100 8
90
80
-70
-60
-50
-40
-30
-20
-10
O
1980
S,
!•»
(D
TJ
O
•o
5T
5'
3
(D
TO
O
Figure 2-1
Comparison of the death
rate due to typhoid and the
percentage of population
served by public water
suppliers in Massachu-
setts from 1860 to 1970.
Source: Fair et al., 1971;
USCB, 1975.
General Board of Health, and, in the United States, the creation of the Massachu-
setts State Board of Health in 1869 (Okun, 1996) and the New York State Board
of Health in 1880 (Rowland and Heid, 1976).
The technological impacts of the "Great Sanitary Awakening" on the origins
of drinking water treatment and water pollution control systems are well docu-
mented in the records of a series of international sanitary conferences held from
1851 through 1938. The conferences addressed scientific issues related to public
health, the environment, and the need to control diseases spread by contaminated
food and water. The conferences highlighted serious public health and environ-
mental issues that have since evolved as the foundation of the numerous state,
local, federal, and international environmental laws and programs enacted in the
latter half of the 20th century (Howard Jones, 1975).
Impacts on Water Resources Users
Sewer is an Old English word meaning "seaward." As the name suggests,
from the 1500s through mid-1800s, London's sewers were nothing more than
open ditches draining wastewater seaward via the Thames River. The year 1858,
also known as the year of "The Great Stink," brought matters to a head. That
summer the stench from the Thames drove people out of the city by the thou-
sands. The windows of the Parliament building had to be draped with curtains
soaked in chloride of lime. By the end of the summer session, even the most
traditional members had to agree: something had to be done about wastewater.
In response, London officials abolished cesspools and made the use of water
closets, drainage pipes, and centralized sewer collection systems mandatory. Over
in the United States, city officials were also feeling the pressure of a populace
weary of the noxious conditions associated with open sewers. In 1910 about 10
percent of the urban population was serviced by centralized collection systems
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
(FWPCA, 1969). This number increased steadily in the following decades; by
1940, 70.5 million persons (53 percent of the population) were served by them.
Unfortunately, treating drinking water with chlorine and developing efficient
sewage collection systems did little to help water resources users. Raw sewage
deposited into streams, lakes, and estuaries was still raw sewage, whether it was
discharged through an engineered wastewater collection system or through an
open ditch. Collection systems just made the dumping more efficient and com-
plete. And though chlorine proved to be a godsend for public health, it treated only
a pollution symptom, not the cause. Its success, unfortunately, tended to divert
attention away from installing wastewater treatment as a means of protecting
public health (Bulloch, 1989).
Several studies conducted around the turn of the century documented
increasingly noxious conditions in several well-known rivers receiving untreated
urban discharges. These included the Merrimack River (1908), Passaic River
(1896), Chicago Ship and Sanitary Canal (1900), and Blackstone River (1890).
Looking beyond water quality, scientists also began to examine the effect urban
discharges were having on stream biota. Studies were conducted in places like
the Sangamon River in Illinois (1929) (Eddy, 1932), the Potomac River (1913-
1920), and the Shenandoah River (1947-1948) (Henderson, 1949). These and
other early investigations are an invaluable starting point for assessing long-term
trends in the surface water environment.
At the turn of the century, public officials focused most of their attention on
water supply users. The users demanded and received the two services most
important to them: the delivery of clean water and the collection and removal of
wastewater. Support for water resources users, on the other hand, was minimal.
Generally these users captured the attention of city leaders only when conditions
reached crisis levels. Then, in most cases, the response was to deal with ways to
alleviate the symptom rather than the cause of water pollution.
In Chicago, for example, officials became concerned about the increasing
amount of urban water pollution flowing into their backyard water supply source,
Lake Michigan. In response, they built the Chicago Drainage Canal, which
diverted sewage away from the lake and directed it to the Des Plaines River, a
tributary that emptied into the Mississippi River.
After the canal opened in 1900, officials in the downstream city of St. Louis
fumed. They quickly initiated proceedings in the Supreme Court of the United
States against the state of Illinois and the Sanitary District of Chicago. Though St.
Louis eventually lost its case because the city could not prove direct harm to its
water supply from its upstream neighbor, the episode underscored the fact that
effective wastewater treatment was a critical component in the modern urban
water cycle.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
B. Evolution of Wastewater and the Use
of DO and BOD as Indicators of
Water Quality
European history as far back as 400 years ago tells of sewage being col-
lected, dewatered, and transported as "night soil" away from population centers.
In 1857 a British royal commission, in response to noxious conditions in the
Thames, directed Lord Essex to report on alternative ways to dispose of urban
wastewater. Essex concluded that applying wastewater to crops would be
preferable to the current practice of draining it into the river. Wastewater treat-
ment technology has progressed tremendously since those times. Today's facilities
employ a variety of sophisticated physical, chemical, and biological processes to
reduce domestic and industrial wastewater to less harmful by-products.
Primary Treatment
The march toward effective wastewater treatment began in the late 1800s
when municipalities began to build facilities for the purpose of physically separat-
ing out solids and floating debris from wastewater before releasing it to a water-
body (Rowland and Heid, 1976). In many cases, this construction was promoted
by city officials and entrepreneurs, who were rapidly learning that unsightly urban
debris and a delightful growing phenomenon, tourists with leisure dollars to spend,
did not mix. By no coincidence, one of the first of these treatment facilities was
constructed in 1886 next to New York's famous Coney Island beaches. Other
cities with prominent waterfront areas followed suit, and by 1909 about 10
percent of the wastewater collected by municipal sewer systems underwent some
form of physical separation process, now known as primary treatment (OTA,
1987).
The practice of physically screening and settling out solids and floating
debris was a critical first step in incorporating the wastewater treatment compo-
nent into the urban water cycle. Even though primary treatment facilities were
simple in concept, they reduced the concentrations of contaminants entering urban
waterways.
Dissolved Oxygen as an Indicator of Water Quality
In 1900 the United States was primarily an agrarian society, with the
majority of the population living in rural areas (Figure 2-2). In the 1920s and
1930s, a combination of population growth, the Great Depression, and the rise of
urban industries with the increased employment opportunities they afforded
caused the rural/urban population balance to shift in favor of cities. The increasing
volumes of wastewater generated by this influx of people soon overwhelmed the
primary treatment capacity of POTWs, many of which had been underdesigned
from the start. Consequently, the modest water quality gains achieved in many
cities by primary treatment technology were soon overwhelmed by greater
volumes of sewage.
2-7
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
addition to the carbon cycle of production and decomposition, the nitrogen cycle
also influences DO through a series of sequential reactions wherein organic
nitrogen compounds are hydrolyzed into ammonia and ammonia is oxidized to
nitrite and nitrate (nitrification) by autotrophic nitrifying bacteria, with DO con-
sumed as part of these sequential reactions.
The amount of oxygen water can hold at any one time is limited, however,
by the saturation concentration of oxygen. The saturating amount of oxygen gas
from the atmosphere that can be dissolved in water is limited by water tempera-
ture, salt content, and pressure (elevation above sea level). In a sense, then, all
the aerobic aquatic life in a waterbody is in competition for that limited amount of
oxygen. In natural streams there are usually no losers because dissolved oxygen
is continuously replenished from the atmosphere at about the same rate at which
it is used up by aquatic organisms. A problem arises, however, when large
amounts of organic material from sewage or other pollution sources enter the
water and the decomposer population (especially bacteria) explodes in response.
These organisms have the potential to lower, or even completely exhaust, oxygen
in the water. When this occurs, life that depends on the presence of oxygen
(aerobic) in the waterbody dies or, where possible, the biota moves on to waters
with higher oxygen levels.
In the absence of oxygen in water, anaerobic bacteria further break down
organic matter. These organisms obtain energy from oxygen bound into other
substances such as sulfate compounds. Anaerobic processes are much slower
than aerobic decomposition, however, and their end products, such as hydrogen
sulfide, are usually noxious.
Secondary Treatment
Harnessing the power of decomposers to break down organic matter in
wastewater is at the heart of a treatment process now known as secondary
treatment. Two distinct methods of this treatment type evolved around the turn of
the century. The Lawrence Experiment Station in Massachusetts pioneered the
first method in 1892. Called the trickling filter method, it involves spraying waste-
water onto a column of crushed stone on which a community of bacteria, fungi,
protozoa, and insects resides. The organisms take in a portion of the organic
matter and break it down. Some of the breakdown products, such as carbon
dioxide, escape to the atmosphere. Others, like nitrate, remain in solution. Still
other products are absorbed into the organisms themselves. This latter material is
eventually collected in settling tanks as sludge after the organisms die or is
otherwise detached from the stone.
A second method of secondary treatment was advanced around 1913 by the
Lawrence Experiment Station and Ardem and Lockett in England. Known as
activated sludge treatment, it follows the same principles as the trickling filter but
instead of cultivating decomposers on the surface of rocks, organisms are simply
suspended in a tank by a continuous flow of wastewater.
Both methods of secondary treatment result in discharges with substantially
less organic matter than is produced by primary treatment. City officials having
problems with litigious neighbors downstream were especially eager to adopt this
new technology into their urban water cycles. One of the first trickling filter
facilities in the Nation was constructed in the city of Gloversville, New York, in
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
1907. The motivation was not so much citizen demands in Gloversville for a
cleaner river as it was the need to respond to a riparian rights suit filed by the
downstream city of Johnstown. Chicago officials also grew tired of their ongoing
battle with St. Louis and in 1916 constructed the first activated sludge treatment
plant in the Nation (Metcalf and Eddy, 1991).
Officials in most other U.S. cities, however, did not have neighbors like
Johnstown or St. Louis forcing them to upgrade their wastewater treatment
capabilities. Consequently, they were content to embrace a theme reflected in a
leading textbook of the time, Sewage Disposal. The authors of the 1919 publica-
tion argued that municipal dollars were much better spent on health programs than
on sewage purification, and they chided sewage treatment proponents for being
unrealistic in their demands.
Biochemical Oxygen Demand (BOD) as a Measure
of Organic Wasteload Strength
One reason communities were slow to adopt secondary treatment into their
urban water cycle was perception. There was no way to articulate the link
between the organic wastes in wastewater and DO levels in natural waters. In
the 1920s these relationships became clearer with the development of an indicator
called the biochemical oxygen demand (BOD). Performed in a laboratory, the
BOD test measures the molecular oxygen used during a specific incubation period
for the biochemical degradation of organic material, the oxidation of ammonia by
nitrification, and the oxygen used to oxidize inorganic chemical compounds such
as sulfides and ferrous iron.
Historically, the BOD was determined using an incubation period of 5 days
at 20 degrees Celsius (QC). For domestic sewage and many industrial wastes,
about 70-80 percent of the total BOD is decomposed within the first five days at
this temperature (Metcalf and Eddy, 1991). Because of the incubation period,
BOD has been adopted as the shorthand notation for this measurement in the
literature. Expressed as a concentration, the BOD5 measurement allows scientists
to compare the relative pollution "strength" of different wastewaters and natural
waters. The widest application of the BOD5 test, however, is for measuring the
strength and rates of wastewater loadings to and from POTWs and evaluating the
BOD5 removal efficiency of the treatment system.
Because of widespread problems with oxygen depletion in many urban
rivers, several states, especially those in the more populated Northeast, Midwest,
and far West, took a leadership role in the 1930s to encourage municipalities to
upgrade from primary to secondary treatment. By 1950, 3,529 facilities, or about
one-third of the 11,784 municipal treatment plants existing at that time, provided
secondary treatment for 32 million people. At the same time, however, 35 million
people were still connected to systems that discharged raw sewage and 25 million
people were provided only primary treatment (USPHS, 1951). Increasing the
number of facilities that provided at least secondary treatment became a national
issue as the technology was seen as a solution to the pervasive problem of low
levels of DO.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
C. The Federal Role in Implementing
Secondary Treatment in the Nation's
POTWs
The story of federal involvement in water pollution control, and specifically
the secondary treatment issue, is best told in two parts—before and after the
passage of the Federal Water Pollution Control Act Amendments of 1972, also
known as the Clean Water Act (CWA). Before 1972 regulatory authority for
water pollution control rested with the states. Federal involvement was limited to
cases involving interstate waters. Unfortunately, there was a great diversity
among the states in terms of willingness to pay the costs of building and upgrading
POTWs and to enforce pollution control laws.
At the center of the problem was the idea that water pollution could be
controlled by setting ambient water quality standards and that states would go
after dischargers who caused those standards to be violated. In retrospect, this
approach was an enforcement nightmare for several reasons (WEF, 1997):
• The enforcing agency had to prove a particular discharger was causing
a waterbody to be in violation of the ambient water quality standard.
This was difficult because waste loads were allocated among all
dischargers based on methods that were often open to interpretation.
• Most of the time, data with which to support the case against a dis-
charger had to come from the discharger itself. Usually there were no
independent monitoring programs.
• Many waterbodies lacked water quality standards.
• There were few civil or criminal penalties that could be levied against
dischargers who caused water quality standards to be violated.
As the state-led water quality standards approach continued to fail and
water quality conditions continued to spiral downward, both water supply and
water resource users looked to the federal government for leadership and relief.
The CWA was designed to turn the water pollution control tables around com-
pletely, and it did. The following two subsections describe the federal role before
and after passage of the CWA.
The Federal Role In Secondary Treatment Before
the Clean Water Act
The public's concern about raw sewage in the Nation's waterways was not
entirely lost on the U.S. Congress before the turn of the century. Because of the
U.S. Constitution, however, they felt powerless to act on any water resource
issue unless it dealt in some way with interstate commerce. Accordingly, the first
federal legislation dealing with the abatement of water pollution was tied to the
fact that pollution sometimes got so bad that it impeded navigation. The Rivers
and Harbors Act of 1890 specifically prohibited the discharge of any refuse or
filth that would impede navigation in interstate waters. Unfortunately, this act was
greatly "watered down" with the passage of the amended Rivers and Harbors
Act in 1899. It conveniently exempted "refuse flowing from streets and sewers
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
and passing therefrom in a liquid state" from the navigation impedance prohibition.
After the Rivers and Harbors Act of 1899, the Public Health Service Act of 1912
authorized the federal government to investigate waterborne disease and water
pollution. In 1924 the Oil Pollution Act was enacted to control discharges of oil
causing damage to coastal waters.
The next few decades were lean ones in terms of federal involvement in
water pollution control—but not for lack of effort. Between 1899 and 1948 more
than 100 bills about water pollution were introduced. Most languished and died in
the halls of Congress. One, sponsored by Senator Alben W. Barkley and Repre-
sentative Fred M. Vinson (later Chief Justice of the Supreme Court), actually
made it to the President's desk. It, however, received a presidential veto because
of budgetary concerns. The 80th Congress finally broke the impasse and enacted
The Water Pollution Control Act of 1948. This act, along with five amendments
passed between 1956 and 1970, shaped the national vision and defined the federal
role regarding the treatment of wastewater in the United States. It also set the
stage for passage of the landmark Water Pollution Control Amendments of 1972.
Figure 2-4 summarizes the key legislation enacted between 1948 and 1971.
The Water Pollution Control Act of 1948, PL 80-845
The Water Pollution Control Act of 1948 was significant on three accounts.
For the first time Congress accomplished the following:
• Expressed a national interest in abating water pollution for the benefit
of both water supply and water resource customers.
"The pollution of our water resources by domestic and industrial
wastes has become an increasingly serious problem due to the
rapid growth of our cities and industries. Large and increasing
amounts of varied wastes must be disposed of from these concen-
trated areas. Polluted waters menace the public health through the
contamination of water and food supplies, destroy fish and game
life, and rob us of other benefits of our natural resources."
— Senate Report No. 462 of the 80th Congress
Report on the Water Pollution Control Act of 1948
• Established the view that states were primarily responsible for the
control of water pollution and that the federal government's role would
be to provide financial aid and technical assistance—a policy concept
that has continued to the present.
"That in connection with the exercise of jurisdiction over the
waterways of the Nation and in consequence of the benefits result-
ing to the public health and welfare by the abatement of stream
pollution, it is hereby declared to be the policy of Congress to
recognize, preserve, and protect the primary responsibilities and
rights of the States in controlling water pollution . . . and to pro-
vide . . . financial aid to State and interstate agencies and to
municipalities, in the formulation and execution of their stream
pollution programs"
— The Water Pollution Control Act of 1948 (PL 80-845)
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Figure 2.4
Timeline of federal water pollution control acts, 1948 -1971.
1
Water Pollution Control Act of 1948
The Water Pollution Control Act of 1948 authorized
the US Public Health Service to develop comprehen-
sive basin plans for water pollution control and to
encourage the adoption of uniform state laws. $100
million of loans annually to municipalities were
authorized, but no appropriation for treatment
facilities under this act was ever made. However,
the act influenced the states to apply more control
over the discharge of pollutants into their waters.
Water Pollution Control Act of 1961
Comprehensive programs and plans for water
pollution abatement and control were still required.
Grants were limited to 30% of the cost of construc-
tion or $600,000, whichever was less, or $2.4
million for multiple municipal plants. At least half of
the appropriation was to go to cities of 125,000 or
less. The Congress advocated 85% removal of
pollutants in the hearings.
1
Clean Water Restoration Act of 1966
The requirements for state water quality standards
were continued. Each state planning agency
receiving a grant was to develop an effective,
comprehensive pollution control plan for a basin.
The Federal Water Pollution Control Administration,
in a guideline, attempted to require states to
conform to a national uniform standard of second-
ary treatment or its equivalent. This action was
challenged and the guideline was not enforced.
Secretary Udall stated at House hearings that the
states had agreed to the requirement for secondary
treatment. Grants for POTWs are set at 30% with
an increase to 40% if the state paid 30%. The
maximum could be increased to 50% if the state
agreed to pay 25%. A grant could be increased by
10% if it conformed to a comprehensive plan for the
metropolitan area. The limitation of $1.2 million and
$4.8 million for grants was waived if the state
matched equally all federal grants. At least 50% of
the first $100 million in annual appropriations had to
be directed to municipalities of <125,000 people.
1969
Water Pollution Control Act of 1956
Grants for assisting in the construction of municipal
treatment works were authorized and, for the first
time, funded with federal appropriations. The
Surgeon General was directed to prepare compre-
hensive programs for pollution control in interstate
waters in cooperation with states and municipali-
ties, and the state was to prepare plans for
prevention and control of water pollution If there
was no approved plan, no grant was to be made
for constructing treatment facilities. $50 million
annually in grants was authorized. Grants were
limited to 30% of the cost of construction, or
$250,000, whichever was smaller. Legislation in the
states increasingly required secondary treatment
for polluted waters.
Water Quality Act of 1965
For the first time, each state, to receive grants, was
required to have water quality standards, ex-
pressed as water quality criteria applicable to
interstate waters. If the state did not develop
standards, the FWPCA was required to do so. To
comply with these standards and criteria, second-
ary treatment was increasingly necessary.
Construction grants were raised to 30% of
reasonable costs, and an additional 10% was
allowed where the project conformed with a
comprehensive plan for a metropolitan area. At
least 50% of the first $100 million in appropriations
had to go to municipalities of less than 125,000
population. Individual grants were limited to $1.2
million, with a limit of $4.8 million for multiple
municipalities.
1
Water Quality Improvement Act of 1970
The Water Quality Improvement Act of 1970 did not
contain any new provisions regarding required
standards. The requirements for state water quality
standards were continued. However, in hearings
for the act, the authority of EPA to require uniform
treatment limitations for discharges, such as
secondary treatment, was questioned.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Developed activities that required states and the federal government to
work as partners in solving pollution problems in interstate waters.
The act set forth a loan program designed to provide up to $ 100 million per
year for states, municipalities, and interstate agencies to construct needed waste-
water treatment works. Each loan was not to exceed $250,000 and was to bear
an interest rate of 2 percent. Unfortunately, the loan program never saw the light
of day because the program was never funded.
More successful, however, were the partnership programs developed
between the states and the U.S. Public Health Service. The act required the
Surgeon General to
• Work with states and municipalities to prepare and adopt comprehen-
sive programs for eliminating or reducing the pollution of interstate
waters and improving the sanitary conditions of surface and under-
ground waters.
• Encourage the enactment of uniform state laws relating to the preven-
tion and control of water pollution.
• Take action against polluters of interstate waters, with the consent of
the affected state.
In 1952 the Congress acknowledged that these partnership efforts were
paying off and passed Public Law 82-579, which extended the activities autho-
rized by the 1948 act for another 4 years. In 1955 the Senate issued a report that
stated that the act caused more than half the states to improve their pollution
control legislation and programs to better protect their water resources (Sen. Rep.
No. 543, 84th Congress). The report also noted that some states were establishing
water quality standards so stringent that they left municipalities with no choice but
to implement secondary treatment at their facilities.
The Water Pollution Control Act of 1956, PL 84-660
This act was significant because it authorized a grant program for the
construction of wastewater treatment facilities—and then actually funded it. A
total of $150 million was earmarked over the life of the program with a provision
that no more than $50 million could be spent per year. Individual grants were not
to exceed 30 percent of the reasonable cost of construction, or $250,000, which-
ever was smaller. There was one important caveat to obtaining a grant, however:
to be funded, the project must be in conformity with a plan prepared by the state
water pollution control agency and approved by the Surgeon General.
Though language in the act emphasized that the law should not be "con-
strued as impairing or in any manner affecting any right or jurisdiction of the
States with respect to the waters (including boundary waters) of such States," the
requirement for federal approval of a state's water pollution control plan nonethe-
less established a new leadership role for the federal government. If a state did
not follow an approved plan, grant payments could be held up pending an appeal
to a federal court.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
The Federal Water Pollution Control Act of 1961, PL 87-88
Only a few changes were made in the 1961 amendment to the Federal
Water Pollution Control Act. Congress's basic intent with this legislation was to
extend the act through to 1967. Construction grants were authorized to the states
in the total amount of $60 million for FY 1962, $90 million for FY 1963, and $100
million for each of the fiscal years 1964 through 1967.
A grant to a municipality was limited to $600,000 or 30 percent of the
reasonable costs, whichever was less, with a limit of $2.4 million when the project
would serve more than one municipality. At least one-half of the funds appropri-
ated for projects were to go to cities of 125,000 population or less. The require-
ments for comprehensive pollution control programs and plans were carried over
from the act of 1956.
Perhaps the most interesting development concerning federal involvement in
water pollution control appeared not in the act itself, but in language contained in
the accompanying Senate report. Here, for the first time, the Senate mentioned its
desire to see secondary treatment used in municipal waste treatment plants. The
same document also presented a vision for the future and an expression of hope
for completion of the urban water cycle:
"There is every reason to believe that a vigorous research attack
on waste treatment problems would lead to breakthroughs and new
processes which will make it possible to handle ever-increasing
wasteloads, and even to restore streams to a state approaching
their original natural purity . . . If all waste or all water deteriorat-
ing elements could be removed by treatment, a region's water
supply could be used over and over. "
— Senate Report No. 353, 87th Congress
Report on the Water Pollution Control Act of 1961
The Water Quality Act of 1965, PL 89-234
Two important elements were established with the passage of the Water
Quality Act of 1965. First, it created the Federal Water Pollution Control Adminis-
tration (FWPCA) as a separate entity in the Department of Health, Education and
Welfare. FWPCA did not reside there long, however. In 1966 it was transferred
to the Department of the Interior. Then, in 1970, its functions were folded into the
new United States Environmental Protection Agency (USEPA).
Second, the act required each state desiring a grant to file a letter of intent
with the FWPCA committing the state to establishing, before June 30, 1967,
water quality criteria applicable to interstate waters and submitting a plan for the
implementation and enforcement of water quality criteria. If the state chose not to
do this, the FWPCA would do it for the state.
The state's criteria and plan were to be the water quality standards for its
interstate waters and tributaries. The act mandated that these standards must
protect the public health or welfare and enhance the quality of water. Consider-
ation was also to be given to the use and value of public water supplies, propaga-
tion offish and wildlife, recreational purposes, and agricultural, industrial, and
other legitimate needs.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
The construction grants program was continued in this act. The federal
contribution was raised to 30 percent of the reasonable costs, plus an additional 10
percent when the project conformed with the comprehensive plan for a metropoli-
tan area. The authorized amounts for construction grants were set at $150 million
for FY 1966 and FY 1967, with at least 50 percent of the first $100 million
appropriated in those years used for grants for municipalities of 125,000 people or
less. Grants to municipalities were limited to $1.2 million, with $4.8 million set as
the limit when two or more municipalities were served by the same facility.
The Clean Water Restoration Act of 1966, PL 89-753
Basin planning was a key focus of the Clean Water Restoration Act of 1966.
Each state planning agency receiving a grant had to develop an effective compre-
hensive pollution control and abatement plan for basins. A basin was defined as
rivers and their tributaries, streams, coastal waters, sounds, estuaries, bays, lakes,
and portions thereof, as well as the lands drained thereby. Congress mandated
that the plan must:
• Be consistent with water quality standards.
• Recommend effective and economical treatment works.
• Recommend maintenance and improvement of water quality standards
within the basin, as well as methods for financing necessary facilities.
Grants for wastewater treatment facilities were set at 30 percent of the
reasonable cost, which could be increased to 40 percent if the state agreed to pay
not less than 30 percent of the reasonable costs. This maximum could be in-
creased to 50 percent if the state agreed to pay not less than 25 percent of the
estimated reasonable costs of all such grants. A grant could also be increased by
10 percent of the amount of a grant if it was in conformance with a plan devel-
oped for the metropolitan area. To be eligible for any grant a project must be
included in a comprehensive water pollution program and the state water pollution
control plan. Grants were again limited to $1.2 million for individual projects and
$4.8 million for multi-municipal projects. This limitation was waived, however, if
the state agreed to match equally all federal grants made for the project.
Authorized amounts for grants gradually increased from a total of $550
million for FY 1968 to $ 1.250 billion for FY 1971. The total of $2 billion was
authorized for FY 1972 by the Extensions of Certain Provisions of the Federal
Water Pollution Control Act of 1971, PL 92-240.
The Water Quality Improvement Act of 1970, PL 91-224
On March 18, 1968, FWPCA announced that the water quality standards of
28 states had been approved, and all of the states were expected to have ap-
proved standards by June. Soon afterwards, however, FWPCA attempted to
cause states to amend their standards to include an effluent limitation of "best
practicable treatment" or its equivalent for all discharges:
'Wo standards shall be approved which allow any waste amenable
to treatment or control to be discharged into any interstate water
without treatment or control regardless of the water quality criteria
and water use or uses adopted.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Further, no standard will be approved which does not require all
wastes, prior to discharge into any interstate water, to receive the
best practicable treatment or control unless it can be demonstrated
that a lessor degree of treatment or control will provide for water
quality and enhancement commensurate with proposed present and
future water uses."
—FWPCA Guideline, 1968
People questioned what authority the FWPCA thought they had to set "best
practicable treatment" as the minimum level of treatment and what they meant by
that term. In House hearings leading up to the Water Quality Improvement Act of
1970, Secretary Udall explained that "in practice, this guideline usually, but not
always, means secondary treatment of municipal wastes . . . generally the States
have agreed with us with regard to the requirement of secondary treatment." A
number of officials from different states begged to differ with Secretary Udall
and FWPCA's guideline. Not surprisingly, states offered up legal opinions that
bluntly concluded that the FWPCA had no authority to set discharge limitations.
Against this backdrop, the Water Quality Improvement Act of 1970 was
passed. The act continued the authority of the states to set standards of water
quality and the authority of the FWPCA to approve such standards. Congress,
however, chose not to include any new provisions regarding standards or treat-
ment levels.
Deciding that the battle for secondary treatment in municipal wastewater
plants would be best fought on another stage, the FWPCA stepped back and
issued a new construction grant regulation (36 FR 13029) in July 1971 that called
for primary treatment as the minimum level of treatment:
"To be eligible for a grant, a project must be designed to result in
an operable treatment works, or part thereof, which will treat or
stabilize sewage or industrial wastes of a liquid nature in order to
abate, control, or prevent water pollution . . . such treatment or
stabilization shall consist of at least primary treatment, or its
equivalent, resulting in the substantially complete removal of
settleable solids."
— FWPCA Construction Grant Regulation
July 1971 (36 FR 13029)
After the FWPCA was reorganized out of existence, USEPA aggressively
picked up the secondary treatment torch. In June 1972, prior to the passage of the
Federal Water Pollution Control Act of 1972 in October, the Agency issued
regulations that required grant projects to conform to secondary treatment
requirements that included the removal of 85 percent of BOD5 from POTW
influent.
The Agency ruled that secondary treatment could be waived only for
projects that:
• Discharged wastes to open ocean waters through an ocean outfall if
such discharges would not adversely affect the open ocean waters and
adjoining shores, and receive primary treatment before discharge.
• Treated or controlled combined sewer overflows if such projects were
consistent with river basins or metropolitan plans to meet approved
water quality standards.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
The Federal Role in Secondary Treatment After the
Clean Water Act
Enactment of the 1972 Amendments to the Federal Water Pollution Control
Act, now popularly known as the Clean Water Act (CWA), by the 92nd U.S.
Congress redirected national policy for water pollution control onto a new path.
Sparked by publication of Rachel Carson's Silent Spring in 1962 (Carson, 1962),
national publicity about environmental issues during the 1960s led to public
awareness of the existence of nationwide air and water pollution problems and
political demands by the "Green Movement" for governmental action to address
pollution problems (Zwick and Benstock, 1971; Jobin, 1998).
On October 18, 1972, a new era for POTWs began when the 1972 Amend-
ments to the Federal Water Pollution Control Act (PL 92-500) were unanimously
passed by the U.S. Congress and, despite a veto by President Richard M. Nixon,
who thought that the $24 billion investment over 5 years was "excessive and
needless overspending," the act became law (Knopman and Smith, 1993). The
act established a new national policy that firmly rejected the historically accepted
use of rivers, lakes, and harbors as receptacles for inadequately treated wastewa-
ter. Congress's objective was clear. They wanted to "restore and maintain the
chemical, physical and biological integrity of the nation's waters" and to attain
"fishable and swimmable" waters throughout the Nation. With PL 92-500, the
federal government took control of directing and defining the Nation's water
pollution control programs. This commitment led to the completion of the urban
water cycle in many communities across the United States.
Congress recognized that success or failure of PL 92-500's lofty objectives
hinged on a combination of money, compliance, and enforcement. Consequently,
the basic framework of the act included the following.
• Establishment of the National Pollutant Discharge Elimination System
(NPDES), a program that requires that every point source discharger
of pollutants obtain a permit and meet all the applicable requirements
specified in regulations issued under sections 301 and 304 of the act.
These permits are enforceable in both federal and state courts, with
substantial penalties for noncompliance.
• Development of technology-based effluent limits, which serve as
minimum treatment standards to be met by dischargers.
• An ability to impose more stringent water quality-based effluent limits
where technology-based limits are inadequate to meet state water
quality standards or objectives.
• Creation of a financial assistance program to build and upgrade
POTWs. PL 92-500 authorized $5.0 billion in federal spending for fiscal
year 1973, $6.0 billion for fiscal year 1974, and $7.0 billion for fiscal
year 1975. In contrast, the year before the act was passed, a total of
$1.25 billion (federal dollars) was spent. Under the construction grants
program, the federal share was 75 percent of cost from fiscal years
1973 to 1983 and 55 percent thereafter. Additional funds were made
available for projects using innovative and alternative treatment pro-
cesses.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
The story of the Clean Water Act and its evolution from 1972 to the present
day is richly complicated. The purpose of this section is not to summarize all
aspects of this landmark act. Rather, the objective is to focus on the role it played
in implementing secondary treatment in the Nation's POTWs. Other sources,
such as The Clean Water Act, 25th Anniversary Edition, published by the
Water Environment Federation (WEF, 1997), should be consulted for a complete
overview of the act. Figure 2-5 summarizes the key amendments and regulations
that occurred from 1972 to the present.
The Water Pollution Control Act Amendments of 1972 (PL 92-
500) and Secondary Treatment Information (38 FR 22298-
22299), published in final on August 17,1973
After debating the merits of secondary treatment for the better part of two
decades, Congress finally put the issue to rest in the Federal Water Pollution
Control Act Amendments of 1972. Section 301 required POTWs to achieve
effluent limitations based on secondary treatment.
A simple, aggressive schedule was set to meet this requirement. By July 1,
1977, all existing POTWs and all facilities approved for construction before
June 30, 1974, must incorporate secondary treatment. Then, by July 1, 1983,
POTWs must meet an additional level of treatment described in the act as "best
practicable wastewater treatment."
While developing the 1972 Amendments, Congress understood that the term
secondary treatment needed to be carefully researched and clearly articulated
before regulations could be drafted. At the time, several "working" definitions
existed, including one offered by Congressman Vanik in the House debate on the
amendment. He defined secondary treatment as a process that removes 80 to 90
percent of all harmful wastes from POTW influent.
Section 304(d)(l) directed USEPA to investigate and publish in the Federal
Register "information, in terms of amounts of constituents and chemical, physical
and biological characteristics of pollutants, on the degree of effluent reduction
attainable through the application of secondary treatment." USEPA assembled a
work group the next year to accomplish this task and invited outside commenta-
tors and contractors to participate.
Early on, the group decided that the effluent limitations to be used to define
secondary treatment needed to include concentrations of key parameters as well
as percent reduction limits. Also weighing in on the minds of the group was a
congressional and public concern that if percent removal targets were set too
high, incremental environmental benefits would not be worth the cost. Conse-
quently, economic considerations became an important part of the decision-
making process. Figure 2-6 is an example of how costs were analyzed in relation
to percent removal targets for BOD5. The graph shows that costs rise rapidly
beyond the 85 to 88 percent removal level. Analyses such as these helped the
work group put technical capabilities in a practical (i.e., economical) context.
In April 1973 USEPA published a proposed regulation based on the group's
report. After comments were addressed, the Agency issued its final regulation on
August 17, 1973. It defined secondary treatment effluent concentration limits for
the following parameters:
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 2.5: Timeline of federal water pollution control acts, 1972 -1996
Federal Water Pollution Control Act Amend-
ments of 1972
The Federal Water Pollution Control Act of 1972
(later to be renamed the Clean Water Act)
contained the first statutory requirement for a
minimum of secondary treatment by all POTWs.
The act also established the National Pollutant
Discharge Elimination System (NPDES), under
which every discharger of pollutants was required
to obtain a permit. Under the permit each POTW is
to discharge only effluent that had received
secondary treatment. EPA defined secondary
treatment in a regulation as attaining an effluent
quality of at least 30 mg/L BOD5, 30 mg/L TSS, and
85% removal of these pollutants, in a period of 30
consecutive days.
Clean Water Act Amendments of 1981, PL 97-
117
The Clean Water Act Amendments of 1981
amended the Clean Water Act to the effect that
"such biological treatment facilities as oxidation
ponds, lagoons and ditches and trickling filters
shall be deemed the equivalent of secondary
treatment." EPA is directed to provide guidance on
design criteria for such facilities, taking into
account pollutant removal efficiencies and
assuring that water quality will not be adversely
affected (Sec. 304(d)(4)). Regulations to this
effect were published in final on September 20,
1984. Also, a notice was issued to solicit public
comments on "problems related to meeting the
percent removal requirements and on five options
EPA was considering for amending the percent
removal requirements.
I
Secondary Treatment Regulations,
January 27, 1989
This secondary treatment regulation allows
adjustments for dry weather periods for POTWs
serving combined sewers.
Clean Water Act Amendments of 1977
The Clean Water Act Amendments of 1977 created
the 301 (h) program, which waived the secondary
treatment requirement for POTWs discharging to a
marine environment if they could show that the
receiving waters would not be adversely affected.
Extensive requirements had to be met before such
a waiver could be issued.
1
National Municipal Policy, January 30, 1984
The EPA National Municipal Policy was published
on January 30, 1984. It was designed to ensure
that all POTWs met the compliance deadlines for
secondary or greater treatment of discharges. The
key to the policy is that it provides for POTWs that
had not complied by the July 1,1988, deadline to be
put on enforceable schedules. The policy has
been outstandingly successful and has resulted in
significant increases in compliance.
Secondary Treatment Regulations, June 3,
1985
The secondary treatment regulation published in
final on June 3, 1985, revised the previous
regulations published in Title 40, Part 133, of the
Code of Federal Regulations Specifically, on a
30-day average, the achievement of not less than
85% removal of BOD5, CBOD5 and suspended
solids for conventional secondary treatment
processes was required. However, for those
treatment processes designated by the Congress
as being equivalent to secondary treatment (such
biological treatment facilities as oxidation ponds,
lagoons, and ditches, and trickling filters), at least
65% pollution removal was required, provided that
water quality was not adversely affected. Waste
stabilization ponds were given separate sus-
pended solids limits. Special consideration was
provided for various influent conditions and
concentration limits.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
36.5
70
BODs Removal Efficiency (%)
• 5-day biochemical oxygen demand (BOD5). Average value for
BOD5 in effluent samples collected in a period of 30 consecutive days
shall not exceed 30 milligrams per liter (mg/L). The average value for
BOD5 in effluent samples collected in a period of 7 consecutive days
shall not exceed 45 mg/L.
• Total suspended solids (TSS). Average value for TSS in effluent
samples collected in a period of 30 consecutive days shall not exceed
30 milligrams per liter (mg/L). The average value for TSS in effluent
samples collected in 7 consecutive days shall not exceed 45 mg/L.
• Fecal coliform bacteria. Geometric mean of fecal coliform bacteria
values for effluent samples collected in a period of 30 consecutive days
shall not exceed 200 per milliliter (mL). The geometric mean of fecal
coliform bacteria values for effluent samples collected in a period of 7
consecutive days shall not exceed 400 per milliliter (mL).
• pH. Effluent values for pH shall remain within the limits of 6.0 and 9.0.
Also included were percent removal limits for BOD5and TSS. Specifically,
average values for BOD5 and TSS in effluent samples collected in 30 consecutive
days may not exceed 15 percent of the mean of influent samples collected at
approximately the same times during the same period (85 percent removal).
The BOD and TSS limits were chosen based on an assumption that the
wastewater entering a POTW (influent) contains about 200 mg/L of BOD5 and
TSS. Knowing this assumption did not hold true in every case, USEPAmade a
couple of allowances. Specifically, the Agency allowed a POTW to have higher
BOD5 and TSS concentrations in its effluent if the facility received more than 10
percent of its design flow from industrial facilities for which less stringent effluent
limitations had been promulgated.
Special consideration was also given, on a case-by-case basis, to treatment
works served by combined storm and sanitary sewer systems where increased
flows during wet weather prevented the attainment of the defined minimum level
of secondary treatment. Of chief concern was the 85 percent removal require-
Figure 2-6
Cost versus BOD5
removal efficiency of
a new 1 million gallon
per day POTW.
Source: USEPA, 1973.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
merit. In stormy weather, storm water runoff dilutes the normal volume of influ-
ent, lowering BOD5 and TSS concentrations. Expecting to reduce already re-
duced concentrations by 85 percent was beyond the means of many facilities.
Two subsequent amendments to the secondary treatment information were
promulgated on July 26, 1976 (41 FR 30788) and October 7, 1977 (42 FR 5665).
These changes provided for:
• Deletion of the fecal coliform bacteria limitations and clarification of
the pH requirement.
• Special consideration for the TSS effluent limitations applicable to
waste stabilization ponds with wastewater flows of less than 2 million
gallons per day (mgd).
Publishing the regulation defining the minimum level of secondary treatment
to be implemented by POTW facilities by 1977 was a major accomplishment for
USEPA. On the horizon, however, loomed the prospect of developing a second,
more stringent, level of requirements for implementation by July 1,1983. Con-
gress fortunately realized that this second set of requirements, or best practicable
treatment, might not be needed. Section 315(b) of PL 92-500 established a
national study commission to help them make this determination. Composed of
five Senators, five Representatives, and five members of the public, the commis-
sion was given 3 years to accomplish this task. In the end, the group issued
several general recommendations, one of which was that the secondary treatment
effluent limits developed for the 1977 deadline not be changed for the 1983
deadline. Essentially, the commission determined that secondary treatment was
the best practicable treatment for POTWs. Thus, the headaches associated with
setting a second level of requirements were avoided.
The Clean Water Act Amendments of 1977 (PL 95-217)
The tight timetable Congress established for implementing secondary
treatment proved to be unrealistic for many municipalities. In fact, only about 30
percent of major POTWs (those processing 1 million (or more) gallons of waste-
water per day) were in compliance when the July 1, 1977, deadline rolled around.
In many cases, upgrade schedules were slowed due to delays in receiving federal
funds. The Clean Water Act Amendments of 1977 (PL 95-217) responded to this
situation by allowing time extensions for municipalities encountering funding
problems.
Time extensions aside, probably the most significant aspect of PL 95-217 in
terms of secondary treatment was the fact that Congress backed off from PL 92-
500's original objective of having all POTWs implement secondary treatment as a
minimum technology-based standard. Municipalities discharging into ocean waters
had been arguing that the benefits associated with their upgrading to secondary
treatment were not worth the cost. The vastness of the marine environment, they
said, effectively dilutes and incorporates wastes into the water and sea bottom
without harming uses or the environment.
Congress agreed and added Section 301(h) to the Clean Water Act, allowing
marine dischargers to apply for a waiver of secondary treatment requirements.
EPA would subsequently review the application and issue modified NPDES
permits to POTWs that met certain environmental criteria and received state
concurrence. These criteria included
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
• Existence of and compliance with water quality standards.
• Protection and propagation of a balanced indigenous population of fish,
shellfish, and wildlife.
• Allowance of recreational activities.
• Establishment of a monitoring program.
• Satisfactory toxics control programs, including an approved industrial
pretreatment program.
• No additional treatment requirements for other sources.
• Acceptable discharge volume and pollutant limits.
• Protection of public water supplies (desalinization plants).
Municipal Wastewater Treatment Construction Grants
Amendments of 1981 (PL 97-117) and Secondary Treatment
Regulations (49 FR 36986-37014), published in final on
September 20, 1984
When the decade of the 1980s dawned, the goal of implementing secondary
treatment in the Nation's POTWs seemed a long way off. About half of the
20,000 municipal discharges, including more than 100 larger cities, were still not in
compliance with the 1977 deadline. Construction projects were bogged down with
funding problems, complicated regulatory procedures, and lack of staff at state
and federal agencies. To address these and other problems, Congress passed the
Construction Grants Amendments of 1981. Section 301(i) recognized that funding
issues were still holding up secondary treatment compliance and therefore
extended the implementation deadline to July 1, 1988, on a case-by-case basis.
PL 97'-117 and its companion regulations also addressed another concern
involving USEPA's definition of secondary treatment effluent requirements. In
theory, the requirements were not intended to favor one treatment process over
another, yet they did. As it turned out, activated sludge facilities were the only
ones that could consistently meet the requirement of 85 percent removal of BOD5
and TSS limits. This situation caused an immediate problem for the many smaller
communities that had invested in trickling filters, waste stabilization ponds, and
other types of biological wastewater treatment. Even when their facilities per-
formed as designed, they were in noncompliance according to USEPA's standards
for secondary treatment.
Upgrading or replacing these facilities was an expensive proposition. Many
questioned whether environmental benefits gained would be worth the cost.
Congress agreed and PL 97-117 and its companion regulations included the
following:
• Introduced the concept of "equivalent of secondary treatment" to
describe facilities that use a trickling filter or waste stabilization pond as
a principal treatment process and which were not meeting the second-
ary treatment requirements as promulgated by USEPA in 1973.
• Lowered the minimum level of effluent quality to be achieved by those
facilities during a 30-day period as an average value not to exceed 45
mg/L for BOD5 and TSS, an average 7-day value for BOD5 and TSS of
not to exceed 65 mg/L, and a percentage removal of those constituents
of not less than 65 percent (30-day average).
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
• Required that NPDES permit adjustments for "equivalent to secondary
treatment" facilities reflect the performance or design capabilities of
the facility and ensure that water quality is not adversely affected.
National Municipal Policy (49 FR 3832-3833), published on
January 30,1984
Continually pushing back the deadline for implementation of secondary
treatment in POTWs created confusion. The 1972 Amendments had set the
original deadline for compliance for 1977. For some municipalities, it was extended
to 1983 by PL 95-217 and then to 1988 by PL 97-117. The USEPA National
Municipal Policy, published in the Federal Register on January 30, 1984, was
designed to eliminate this confusion and ensure that all POTWs would comply
with the statutory requirements and compliance deadlines in the Clean Water Act.
It also established that where there were extraordinary circumstances that
precluded compliance by the July 1,1988, deadline, POTWs would be put on
enforceable schedules designed to achieve timely compliance. The policy de-
scribed EPA's intentions to focus its efforts on
• POTWs that previously received federal funding assistance and are not
in compliance.
Other POTWs.
• Minor POTWs (less than 1 mgd capacity) that are contributing signifi-
cantly to impairment of water quality.
This municipal treatment policy has been outstandingly successful, with over
90 percent compliance achieved to date for major POTWs (1 mgd or over).
Secondary Treatment Regulations, published in final on
June 3,1985
The secondary treatment requirement of 85 percent removal of BOD5 and
TSS continued to present problems for POTWs receiving diluted influent waste-
water. Whether it was a secondary treatment facility (85 percent removal) or an
equivalent of secondary treatment facility (65 percent removal), to stay in compli-
ance a facility had to install advanced technology, even if it consistently met its
concentration limits. Recognizing this problem, USEPA on November 16, 1983,
published a Federal Register notice soliciting public comment on a number of
options for amending the percent removal requirements.
Based on the public comments received, the Agency proposed and then
finalized a revised Secondary Treatment Regulation. Published in final on June 3,
1985, it authorized USEPA to lower the percent removal requirement, or substi-
tute a mass limit for the percent removal requirement, for certain POTWs. The
Agency would make this determination on a case-by-case basis based on the
removal capability of the treatment plant, the influent wastewater concentration,
and the infiltration and inflow situation.
Treatment plants could apply for a permit adjustment in its percent removal
limit only if
The treatment plant is meeting or will consistently meet its other permit
effluent concentration limitations, but its percent removal requirements
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
cannot be met due to less concentrated influent wastewater for sepa-
rated sewers.
To meet the percent removal requirement, the treatment works would
have to meet significantly more stringent concentration-based limita-
tions.
• The less concentrated influent wastewater to the treatment works was
not a result of excessive infiltration and inflow.
The concentration limits in the permit would remain unchanged, and in no
case was a permit to be adjusted if the permitting authority determined that
adverse water quality impacts would result from a change in permit limits.
Amendment to the Secondary Treatment Regulation, published
in final on January 27,1989 in the Federal Register
The Secondary Treatment Regulation published in June 1985 addressed the
problem POTWs with separate sewers had in meeting percent reduction stan-
dards due to the dilution of influent wastewater by wet weather conditions. The
city of New York also had a problem. Its combined sewer system delivered
diluted influent to city POTWs, even during dry weather. Consequently, the city
petitioned to be eligible for adjustments of percent removal requirements, too,
arguing that nonexcessive infiltration can dilute the influent wastewater of treat-
ment works served by combined sewers just as it does for treatment works
served by separate sewers. USEPA agreed with this position and published an
amendment to the regulation on January 27, 1989, to allow for percent removal
adjustments during dry weather periods for POTWs with combined sewers. To
obtain this adjustment the treatment works had to satisfy three conditions:
It must consistently meet its permit effluent concentration limitations,
but the percent removal requirements cannot be met due to less
concentrated influent wastewater.
• Significantly more stringent effluent concentration than those required
by the concentration-based standards must be met to comply with the
percent removal requirements.
• The less concentrated influent wastewater must not result from either
excessive infiltration or clear water industrial discharges to the system.
Regarding the last condition, the regulation established that if the average
dry weather base flow (i.e., the total of the wastewater flow plus infiltration) in a
combined sewer system is less than 120 gallons per day per capita (gpcd) thresh-
old value, infiltration is assumed to be nonexcessive. However, sewer systems
with average dry weather flows greater than 120 gpcd might also have
nonexcessive infiltration if this is demonstrated on a case-by-case basis. An
applicant, therefore, has an opportunity to demonstrate that its combined sewer
system is not subject to excessive infiltration even if the average total dry weather
base flow exceeds the 120 gpcd threshold value.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
D. Nationwide Trends in BOD Loading
Based on Population and POTW
Treatment Design
From 1940 to the present day, the combination of advancing wastewater
treatment technology, increased public concern, various state wastewater treat-
ment regulations, and, finally, the 1972 CWA secondary treatment mandate
resulted in an increased number of POTWs with at least secondary and, in many
cases, greater than secondary levels of treatment. Table 2-2 presents descriptions
of the six major types of treatment found at POTWs along with their correspond-
ing design-based BOD5 removal efficiency1 (expressed as percent removal).
The total population in the United States grew rapidly in the latter half of the
20th century, increasing from around 140 million people in 1940 to about 270
million in 1996 (see Figure 2-2). This population growth meant POTWs not only
had to upgrade their treatment processes to increase pollutant removal efficiency,
but they had to accomplish it while dealing with increasing influent wastewater
loads. This section examines trends concerning the Nation's expansion and
upgrades of POTWs and analyzes how increased use of secondary and greater
than secondary treatment after the 1972 CWA affected the rate of effluent BOD
loading to the Nation's waterways. Specifically examined are the following:
• The inventory of POTWs in the United States.
• The number of people served by those POTWs and the amount of
wastewater flow they generated.
The rate of BOD entering POTWs (influent loading).
• The rate of BOD discharged by POTWs into receiving waterways
(effluent loading).
• BOD removal efficiency of POTWs
• Proj ections of effluent BOD loading into the 21 st century.
The information sources for this study include municipal wastewater inven-
tories published by the U.S. Public Health Service from 1940 through 1968
(USPHS, 1951; NCWQ, 1976; USEPA, 1974) and USEPA's Clean Water Needs
Surveys (CWNS) conducted from 1973 through 1996 (USEPA, 1976, 1978, 1980,
1982, 1984, 1986, 1989, 1993, 1997). Many of these sources categorize their
information by the six types of wastewater treatment described in Table 2-2.
Some sources, however, combine primary and advanced primary data and report
it simply as "less than secondary" treatment data. Similarly, data for advanced
secondary and advanced wastewater treatment are combined and reported as
"greater than secondary" treatment data. To keep the categories consistent, this
convention was followed in the analyses presented in this section.
Designed-based BOD5 removal efficiencies are minimum requirements typically assigned by
NPDES permits according to the treatment process and treatment plant design assumptions
(Metcalf and Eddy, 1991). Generally, they represent conservative estimates of BOD5 removal
efficiencies. Many modern POTWs report a higher rate of BOD5 removal than their permitted
rate. This study, however, focuses on designed-based BOD5 removal efficiencies because it is
assumed that these conservative rates would provide a more effective and consistent
comparison of BOD5 removal over the entire historical period of record used in the analysis.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-2. Six levels of municipal wastewater treatment.
Treatment Design BODS
Type Removal Efficiency Description
Raw
0%
Wastewater is collected and discharged to surface waters without treatment,
or removal, of pollutants from the influent stream.
Primary
35%
Incorporates physical processes of gravitational settling to separate settleable
and floatable solids material from the raw wastewater. The removal of
settleable solids results in the removal of pollutants associated with solid
particles such as organic matter, nutrients, toxic chemicals, heavy metals, and
pathogens. Other physical processes such as fine screens and filters can also
be used.
Advanced
Primary
50%
Enhancement of the primary clarification process using chemical
coagulants such as metal salts and organic polyelectrolytes.
Secondary
Activated sludge
Waste stabilization
ponds
• Trickling filters
Advanced Secondary
85% Biological processes are added to break down organic matter in the primary
effluent by oxidation and production of bacterial biomass. Biological waste
treatment systems, based on bacterial decomposition of organic matter, can be
classified as activated sludge, waste stabilization ponds (suspended bacterial
growth), and trickling filters (attached bacterial growth). 84 to 89 percent
removal of TSS and 30 mg/L effluent concentration for BOD5 and TSS.
Involves the use of bacteria to decompose suspended solids in the sewage so
that they can be settled out. Oxygen to speed the bacteriological process is
generated by mechanical aeration or by the infusion of additional oxygen. The
solids produced (sludge) by the biological action are settled out and removed,
except for a portion of the bacteria-rich sludge that is returned to the head of
the secondary treatment process to activate the biological processes to treat
sewage. This is the standard method of treatment for medium and large cities.
Pools in which mechanical aeration is used to supply oxygen to
the bacteria. In other processes, oxygen is supplied by natural surface aeration
or by algae photosynthesis with no mechanical aeration.
Employs a bed of highly permeable media such as crushed stone or plastic to
which are attached microcosms for treating sewage sprayed on the media by a
mechanical arm.
90% The conventional secondary treatment process incorporates chemically
enhanced primary clarification and/or innovative biological treatment processes
to increase the removal efficiency of suspended solids, BOD, and total
phosphorus. Sludge production is typically increased overall as a result of the
chemical enhancement of primary clarification and biological processes.
Effluent concentrations of BOD5 range from 10 to 30 mg/L and processes
included to remove ammonia and phosphorus in excess of effluent levels
typical for secondary treatment.
Advanced Wastewater 95%
Treatment
Advanced wastewater treatment (AWT), or tertiary treatment, facilities
are designed to achieve high rates of removal of nutrients (nitrogen or phos-
phorus), BOD, and suspended solids. Nitrogen removal is achieved by en-
hancement of the biological processes to incorporate nitrification (ammonia
removal) and denitrification (nitrate removal). Phosphorus removal is accom-
plished by either chemical or biological processes. Addition of high doses of
metal salts removes phosphorus while biological processes are dependent on
the selection of high-phosphorus microorganisms. Additional removal of
nutrients and organic carbon can be accomplished using processes such as
high lime, granular activated carbon, and reverse osmosis. Effluent BOD5 is
generally less than 10 mg/L, and total-N removal is more than 50 percent.
Note:
Readers desiring more technical details about these processes should review standard engineering reference texts
(e.g., Metcalf & Eddy, 1991) or technical reports on wastewater treatment (e.g., NRC, 1993). Effluent removal effi-
ciency and concentrations are from the 1978 USEPA Needs Survey (USEPA, 1978).
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 2-7
Relationship between the
carbonaceous,
nitrogenous, and total
BOD.
Source: Thomann and
Mueller, 1987.
Types of BOD Reported in This Trends Analysis
BOD5 is the most widely used measurement of BOD. In spite of its popular-
ity, there are important limitations of this measurement. The subscript "5" refers
to the laboratory incubation period of 5 days at 20 QC. Many biochemical reactions
that determine the ultimate consumption of DO in both wastewater and natural
waters are not completed within the 5-day limit, however. Therefore, an estimate
of "ultimate" BOD (BODJ of a sample requires consideration of all the bio-
chemical processes that consume DO over a longer time scale. Figure 2-7
presents the relationships among the components of BOD .
Familiar to most environmental engineers is the oxygen demand associated
with the bacterial decomposition of carbonaceous organic matter under aerobic
conditions. Through respiration, organic matter is broken down and oxygen is
consumed. Parameters in Figure 2-7 relating to carbonaceous BOD are:
• CBOD5—BOD at 5 days that includes only the carbonaceous compo-
nent of oxygen consumption.
• CBOD—BOD at an unspecified time that includes only the carbon-
aceous component of oxygen consumption.
• CBOD —Ultimate BOD of carbonaceous component of oxygen
consumption at completion of decomposition process.
Along with the decomposition of carbonaceous matter is an additional
oxygen demand associated with nitrification, the process that converts ammonia
to nitrate. Nitrogen in wastewater generally appears as organic nitrogen com-
pounds (urea, proteins, etc.) and ammonia. Over time, the nitrogen compounds
are hydrolyzed and are converted to ammonia. Autotrophic bacteria of the genus
Nitrosomonas convert the ammonia to nitrite, using oxygen in the process. Nitrite,
in turn, is converted to nitrate by bacteria of the genus Nitrobacter, consuming
additional oxygen in the process. Parameters in Figure 2-7 relating to nitrogenous
BOD are
• NBOD—BOD at an unspecified time that includes only the nitrogenous
component of oxygen consumption from nitrification.
• NBODu—Ultimate BOD of the nitrogenous component of oxygen
consumption at completion of nitrification process.
Total BOD
BOD
BOD,,
CBOD
Incubation time, days
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
In Figure 2-7, carbonaceous and nitrogenous BOD components combine to
yield the following parameters:
• BOD5—BOD at 5 days that includes the carbonaceous and nitrog-
enous components of oxygen consumption.
• Total BOD—BOD at an unspecified time that includes the carbon-
aceous and nitrogenous components of oxygen consumption.
• BODu—Ultimate BOD of the carbonaceous and nitrogenous compo-
nents of oxygen consumption at completion of both the carbonaceous
decomposition and nitrification processes.
The length of time needed to reach the "ultimate" endpoints of the carbon-
aceous and nitrogenous components designated in Figure 2-7 (CBODu and
NBODu) depends on several factors, including the composition of the wastewater
and the corresponding rate of decomposition for its components. For predomi-
nately labile fractions of organic carbon that are easy for bacteria to decompose
(e.g., mostly sugars, short chain molecules), decomposition can be completed
within about 20 to 30 days. In contrast, for refractory organic matter that is
strongly resistant to bacterial decomposition (e.g., mostly cellulose, long chain
molecules such as pulp and paper waste), complete decomposition might require
an incubation period of anywhere from 100 to 200 days. Decomposition rates for
a sample of wastewater effluent from a POTW with secondary treatment,
consequently, tend to be lower than rates from raw wastewater because the
easily decomposed sugars have already been removed by the treatment process.
Timing of the nitrification process is also dependent on several factors.
These include the ratio of organic nitrogen compounds to ammonia and the lag
time necessary to hydrolyze and convert the compounds to ammonia, the pres-
ence of adequate numbers of nitrifying bacteria in the water to begin the nitrifica-
tion process, alkaline pH levels, and the presence of sufficient oxygen for bacte-
rial respiration. The net effect of these factors is to inhibit nitrification immediately
downstream from POTW outfalls (Chapra, 1997). Similarly, in a laboratory
sample if a "seed" population is not available for nitrification during the 5-day
incubation period, the measured BOD5 will reflect only the carbonaceous compo-
nent (i.e., CBOD5). If, however, factors are sufficient for nitrification to occur in
the laboratory sample, the measured BOD5 will reflect both the carbonaceous and
nitrogenous components (see Hall and Foxen, 1984).
Is incorporating the nitrogenous component and using BODu important
enough to eschew the more familiar carbonaceous CBOD5 when presenting BOD
information? The answer is yes. Chapra (1997) calculates that the oxygen
consumed in nitrification is about 30 percent of the oxygen consumed in carbon-
aceous oxidation of pure organic matter. If this finding was not persuasive enough
for the inclusion of nitrification in an analysis of BOD, he also presents evidence
that concentrations of NBOD and CBOD are actually nearly equivalent in
untreated wastewater. Chapra theorizes that the discrepancy between calculated
and the actual concentrations may be attributed to the fact that not all organic
matter might be decomposable under the conditions of the BOD test and that
nitrogen in wastewater might not all come from organic matter. Fertilizers and
other sources likely add to the nitrogen pool, increasing the significance of NBOD
in the environment.
2-29
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
In sum, the true measure of the long-term oxygen demand of influent and
effluent BOD loading and its effect on water quality in streams and rivers can be
determined only if both the carbonaceous and nitrogenous components of BOD
are combined and analyzed as BODu. Since it is impractical for most monitoring
programs and laboratories to extend the incubation period beyond the traditional
5 days associated with the determination of BOD5, other surrogate methods must
be used to determine CBOD , NBOD and BOD . Discussed below are the
u ' u u
methods used in this study to determine these parameters.
Determination of CBOD5 and CBODu
BOD loading data for municipal and industrial wastewater dischargers are
most often reported in NPDES permit limits and Discharge Monitoring Reports
(DMRs) as either BOD5 or CBOD5. Unfortunately, in analyzing historical loading
trends of municipal effluent it is impossible to determine if BOD5 data compiled
by various data sources included the suppression of possible nitrification during
the laboratory analysis. In compiling long-term BOD loading trends, therefore, it is
frequently assumed that BOD5 is approximately equal to CBOD5 (see Lung,
1998). This report makes the same assumption. Consequently, for the purposes of
this study all BOD5 data reported to the USEPA are considered to be CBOD5.
Leo et al. (1984) and Thomann and Mueller (1987) point out that conversion
ratios for estimating CBODu concentrations based on either BOD5 or CBOD5
concentrations are dependent on the level of wastewater treatment. The propor-
tion of easily degraded (labile) organic matter in the effluent declines as the
efficiency of wastewater treatment is improved by upgrading a facility. In an
analysis of effluent data from 114 primary to advanced municipal wastewater
treatment plants, Leo et al. (1984) determined mean values of 2.47 and 2.84 for
the CBODu/BOD5 and CBODu/CBOD5 ratios, respectively. The differences in
the two ratios reflect the oxygen demand from nitrification associated with the
BOD5 data (see Hall and Foxen, 1984).
The assumption in this study that all BOD5 concentrations reported to
USEPA are actually CBOD5 concentrations reduces the focus to only CBODu/
CBOD5 ratios as they relate to various levels of municipal wastewater treatment.
Table 2-3 presents conversion ratios for four wastewater treatment types—raw,
less than secondary, secondary, and greater than secondary. The formula for this
conversion is:
CBOD = CBOD, [CBOD /CBOD, ratio] Eq. (2.1)
Table 2-3. CBODu/CBOD5 conversion ratios. Source: Thomann and Mueller,
1987; Leo et al., W84)
| Municipal Wastewater Treatment Type
Less than Greater than
Raw Secondary3 Secondary Secondary13
1.2 1.6 2.84 2.9
a Primary and advanced primary wastewater treatment
b Advanced secondary and advanced wastewater treatment
2-30
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Determination of NBODu
Recall that nitrogen in wastewater generally appears as organic nitrogen
compounds and ammonia and that the organic nitrogen fraction can be
remineralized to ammonia and contribute to the oxygen demand in a receiving
water. NBOD, therefore, is defined as the oxygen equivalent of the sum of
organic nitrogen and ammonia. Conveniently, total Kjeldahl nitrogen (TKN) is
defined as the sum of organic nitrogen and ammonia-nitrogen and can be used
with the stoichiometric equivalent oxygen:nitrogen ratio (O2:N). A total of 4.57 g
oxygen per 1 g nitrogen consumed in the nitrification process provides the basis
for estimating the NBODu of a sample. The formula for converting TKN to
NBODU concentration is:
y = 4.57 [TKN] Eq. (2.2)
Determination of BODu
The ultimate biochemical oxygen demand is determined by simply adding the
carbonaceous and nitrogenous components.
BODy - [CBODJ + [NBODu ] Eq. (2.3)
Trends in POTW Inventory
USPHS municipal wastewater inventories and the USEPA Clean Water
Needs Surveys were the primary data sources used to document the inventory of
POTWs in the United States before and after the CWA. Table 2-4 presents the
national inventory for select years from 1940 to 1996 organized by treatment type.
Figure 2-8 is a column chart displaying the POTW inventory data. The "No
Discharge" category (data available beginning in 1972) refers to facilities that do
not discharge their effluent to surface waters. Most facilities that fall into this
category are oxidation/stabilization ponds designed for evaporation and/or infiltra-
tion of effluent. Other examples of "No Discharge" facilities include recycling,
reuse, and spray irrigation systems.
Key observations from Table 2-4 and Figure 2-8 include the following:
• The total number of POTWs in the Nation increased by about 36
percent between 1950 and 1996.
• POTWs providing only raw and less than secondary treatment de-
creased in proportion to facilities providing secondary and greater than
secondary treatment during the 1950-1996 time period. In 1950, only 30
percent of POTWs nationwide (3,529 of 11,784 facilities) provided
secondary treatment. In 1968, 4 years before the CWA, 72 percent of
the POTWs (10,052 of 14,051 facilities) had secondary treatment or
greater. By 1996, 24 years after the 1972 CWA, 99 percent of the
Nation's 16,024 POTWs were providing either secondary treatment or
greater or were no discharge facilities.
• In 1968, 72 percent of the Nation's POTWs were providing secondary
treatment and less than 1 percent were providing greater than second-
ary treatment. By 1996, 59 percent of POTWs were providing second-
ary treatment and 27 percent had greater than secondary treatment.
2-31
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-4. Inventory of POTWs by wastewater treatment type, 1940 - 1996. Source: U.S. Public Health Service
Municipal Wastewater Inventories and USEPA Clean Water Needs Surveys.
TREATMENT TYPE --
Inventory of POTWs
Total
Raw
Less than
Secondary
Secondary
Greater than
Secondary
-I
No
Discharge
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
NA
11,784
11,698
14,051
19,355
14,850
15,662
15,708
15,613
16,024
NA
5,156
2,262
1,564
2,265
91
237
117
0
0
2,938
3,099
2,717
2,435
2,594
4,278
3,119
1,789
868
176
2,630
3,529
6,719
10,042
9,426a
6,608
7,946
8,536
9,086
9,388
0
0
0
10
461
2,888
2,760
3,412
3,678
4,428
NA
NA
NA
NA
142
985
1,600
1,854
1,981
2,032
This total excludes 4,467 oxidation ponds and 142 land application facilities classified as secondary treatment facilities in
EPA's 1972 inventory of municipal wastewater facilities (USEPA, 1972). They were excluded because (1) EPA did not
categorize oxidation ponds as secondary treatment facilities in any other year covered in this analysis and (2) land
application facilities are classified as "no discharge" facilities in subsequent years and therefore (to be consistent) they
were included in the no discharge facilities category for 1972.
Figure 2-8
Number of POTWs
nationwide for select years
between 1940 and 1996
organized by wastewater
treatment type.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
Trends in Population and Influent Wastewater Flow
to POTWs
USPHS municipal wastewater inventories and the USEPA Clean Water
Needs Surveys were the primary data sources used to document the population
served by POTWs and the rate of influent wastewater flow to them between
1940 and 1996. Actual influent wastewater flow data were available from reports
prepared for 1978, 1980, 1982, 1984, and 1986. For the years in which these data
2-32
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
were not available, influent wastewater flow data were estimated based on the
population served and an assumed constant normalized flow rate of 165 gallons
per capita per day (gpcd). The influent wastewater flow rate of 165 gpcd is based
on the mean of the total population served and wastewater flow data compiled in
the USEPA Clean Water Needs Surveys for the five years for which actual
wastewater flow data were reported (data ranged from 160 to 173 gpcd).
Influent wastewater includes residential (55 percent), commercial and
industrial (20 percent), stormwater (4 percent), and infiltration and inflow (20
percent) sources of wastewater flow (AMSA, 1997). The constant per capita
flow rate of 165 gpcd used in this study is identical to the typical U.S. average
within the wide range (65 to 290 gpcd) of municipal water use that accounts for
residential, commercial and industrial, and public water uses in the United States
(Metcalf and Eddy, 1991).
Table 2-5 presents the population served by POTWs and the rate of influent
wastewater flow to POTWs nationally for select years from 1940 to 1996. Figure
2-9 is a column chart displaying the population data.
Key observations from Table 2-5 and Figure 2-9 include the following:
• The population served by POTWs in the Nation increased significantly,
from about 91.8 million people in 1950 to about 140.1 million in 1968
(four years before the 1972 CWA). By 1996, 189.7 million people were
connected to POTWs, a 35 percent increase from 1968.
• The number of people relying on POTWs with less than secondary
treatment dropped rapidly after passage of the 1972 CWA. In 1968 (4
years before the CWA), about 39 percent of the 140.1 million people
were served by POTWs providing only raw or less than secondary
wastewater treatment. By 1996 (24 years after the 1972 CWA), this
percentage was reduced to about 9 percent; only 17.2 million people of
the 189.7 million served by POTWs received less than secondary
wastewater treatment.
Stated another way, the U.S. population served by POTWs with
secondary or greater treatment almost doubled between 1968 and
1996 from 85.9 million people in 1968 to 164.8 million people in
1996! (It is noted that 5.1 million of the 17.2 million people served by
less than secondary facilities in 1996 were connected to 45 POTW
facilities granted CWA Section 301(h) waivers (9 pending final waiver
decision as of November 1998), which allow the discharge of primary
or advanced primary effluent to deep, well-mixed ocean waters.)
• Although the number of people served by POTWs with secondary
treatment remained fairly constant between 1968 and 1996 (a slight
decrease of 3.7 million people or about 4 percent of the population), the
number of people provided with greater than secondary treatment
increased significantly (from 0.3 million people in 1968 to 82.9 million
people in 1996). This is consistent with the trend since 1968 in increas-
ing numbers of POTWs providing greater than secondary treatment, as
shown in Table 2-4.
2-33
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-5. Population served by and influent
1940-1996.
.
1
| Population Served by POTWs (millions) ^^^
Total Raw
1940 70.5 32.1
1950 91.8 35.3
1962 118.3 14.7
1968 140.1 10.1
1972 141.7 4.9
1978 155.2 3.6
1982 163.5 1.9
1988 177.5 1.4
1992 180.6 0.0
1996 189.7 0.0
• Influent Wastewater Flow to POTWs (mod) m
Year Total Raw
1940 11,682 5,313
1950 15,141 5,819
1962 19,520 2,409
1968 23,117 1,667
1972 23,384 815
1978 26,800 601
1982 27,203 310
1988 29,294 226
1992 29,801 0
1996 31,302 0
wastewater flow
_ TDI
— ___ | |^|
Less than
Secondary
18.4
24.6
42.2
44.1
51.9
44.1
33.6
26.5
21.7
17.2
Less than
Secondary
3,053
4,059
6,963
7,277
8,560
7,152
5,301
4,370
3,583
2,834
to POTWs by wastewater treatment type,
EATMENTTYPE
Secondary
20.0
31.9
61.5
85.6
76.3
56.3
67.6
78.0
82.9
81.9
Secondary
3,317
5,263
10,148
14,124
12,585
10,139
11,010
12,863
13,680
13,521
f^rpofAr than
\Jtt COICI LI 101 1
Secondary
0.0
0.0
0.0
0.3
7.8
49.1
56.3
65.7
68.2
82.9
Greater than
Secondary
0
0
0
50
1,288
8,545
10,092
10,832
11,258
13,683
I
__i
MO
t^HJ
Discharge
NA
NA
NA
NA
0.8
2.2
4.2
6.1
7.8
7.7
No
Discharge
NA
NA
NA
NA
136
363
491
1,003
1,281
1,264
Figure 2-9
Population served by
POTWs nationwide for
select years between 1940
and 1996 organized by
wastewater treatment type.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
to
.8
•o
Q)
0)
CO
O.
O
Q.
200-j
180-
160-
140
120-
100-
80
60
40
20
0
H No Discharge
D > Secondary
H Secondary
M < Secondary
• Raw
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
2-34
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Trends in Influent BOD Loading to POTWs
Table 2-6 presents nationwide influent loading of CBOD5, CBODu, NBODu,
and BODu organized by wastewater treatment type for select years from 1940 to
1996.
Data Sources and Calculations
The USEPA Clean Water Needs Surveys were the primary data source
used to estimate the nationwide rate of influent CBOD5 loading to POTWs.
Actual influent CBOD5 loading data were reported for 1978, 1980, 1982, 1984,
and 1986. For the years for which data were not available, per capita influent
loading was assumed to be 0.296 Ib CBOD5 per person per day. This rate was
based on an estimated constant normalized flow rate of 165 gallons per capita per
day and an influent CBOD5 concentration of 215 mg/L. The use of 215 mg/L as
the influent CBOD5 concentration is consistent with several other estimates of
raw wastewater strength (e.g., AMSA, 1997; Tetra Tech, 1999; Metcalf and
Eddy, 1991). It also is the mean nationally aggregated ratio of the total influent
CBOD5 loading rate normalized to total wastewater flow reported in the USEPA
Clean Water Needs Surveys for the 5 years that actual wastewater flow data
were reported (range from 209 to 229 mg/L). Sources of influent BOD include
residential, commercial and industrial, and infiltration and inflow contributions.
Some readers might note that an influent loading rate of 0.296 Ib CBOD5
per person per day is almost twice the typical "textbook" value of 0.17 Ib CBOD5
per person per day, sometimes referred to as the "population equivalent" (PE)
rate. Textbook values, however, usually account for only the average per capita
residential load contributed by combined stormwater and domestic wastewater.
The industrial and commercial components are excluded (see Fair et al., 1971).
To provide a more complete characterization of influent BOD loading inclusive of
all sources, the higher figure was used in this study.
CBODu data were determined using CBOD5 data and Equation 2.1 as
follows:
CBODu - CBOD5 [1.2] Eq. (2.4)
where: 1.2 = CBOD /CBOD, ratio associated with raw wastewater
u 5
The USEPA Clean Water Needs Surveys were the primary data source
used to estimate the nationwide rate of influent NBODu loading to POTWs.
Actual influent TKN loading data were reported for 1978, 1980, 1982, 1984, and
1986. For the years for which wastewater flow data were not available, per
capita influent loading was assumed to be 0.191 Ib NBOD per person per day.
This rate was based on an estimated constant normalized flow rate of 165 gallons
per capita per day and an influent TKN concentration of 30.3 mg/L, a level
derived from an analysis of about 100 wastewater facilities (AMSA, 1997). In-
fluent NBOD loading was determined using influent TKN data and Equation 2.2.
Trends in Influent CBOD5 and BODu Loading to POTWs
Figure 2-10 is a column chart that compares total influent CBOD5 and
BODu loading from 1940 to 1996. Figures 2-11 (a) and (b) display influent CBOD5
and BODu loading data, respectively, organized by wastewater treatment type.
2-35
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-6. Influent BOD loading to POTWs by wastewater treatment type, 1 940 - 1 996.
[ Influent CBOD5 Loading (metric tons per day)
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
9,508
12,323
15,886
18,814
19,032
21,253
21,170
23,841
24,254
25,476
Raw
4,324
4,736
1,961
1,356
663
489
252
184
0
0
• Influent CBODu Loading (metric tons per day)
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
11,409
14,787
19,063
22,576
22,838
25,503
25,405
28,609
29,105
30,571
Raw
5,189
5,683
2,353
1,628
796
587
302
220
0
0
• Influent NBODu Loading (metric tons per day) 1
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
6,123
7,936
10,232
12,117
12,257
14,047
14,259
15,355
15,621
16,408
Raw
2,785
3,050
1,263
874
427
315
162
118
0
0
• Influent BOD Loading (metric tons per day) m
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
17,532
22,723
29,295
34,693
35,095
39,551
39,663
43,964
44,726
46,979
••••^^^^^^^^^^^^^^^^^
Raw
7,974
8,734
3,615
2,501
1,223
901
465
339
0
0
l_p
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Figure 2-10
Total influent BODu and
CBOD5 loading, 1940 to
1996.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
_^ 50,000
-g 45,000
j| 40,000
35,000
30,000
25,000
o>
O)
•a
o 20,000
g 15,000
m
~ 10,000
0)
2. 5,000
V|—
~ 0
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
Figure 2-11
Influent loading of
(a) CBOD5 and (b) BODu
to POTWs nationwide for
select years between 1940
and 1996 organized by
wastewater treatment type.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
(a)
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
(b)
1
I
O)
c
'•&
OS
O
Q
O
m
0»
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
2-37
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Key observations from Table 2-6 and Figures 2-10 and 2-11 include the
following:
• Influent BOD loading to the Nation's POTWs more than doubled from
1940 to 1996, reflecting population growth, increases in the number of
facilities, and expanding service areas.
• Influent CBOD5 loading increased from 9,508 metric tons per day in
1940 to 18,814 metric tons per day in 1968. By 1996, influent CBOD5
loading stood at 25,476 metric tons per day, a 35 percent increase from
1968.
• Influent BODu loading increased from 17,532 metric tons per day in
1940 to 34,693 metric tons per day in 1968. By 1996, influent BODu
loading stood at 46,979 metric tons per day, a 35 percent increase from
1968.
• In 1940, 72 percent of influent BODu loading nationwide was being
treated by facilities with less than secondary treatment (12,555 of
17,532 metric tons per day of BODJ. By 1968, 39 percent of influent
BODu loading nationwide was being treated by facilities with less than
secondary treatment (13,422 of 34,693 metric tons per day of BODu).
Twenty-four years after the 1972 CWA, only 9 percent of influent
BODu loading was being treated by facilities with less than secondary
treatment (4,254 of 46,979 metric tons per day of BODu).
Trends in Effluent BOD Loading from POTWs
Table 2-7 presents nationwide effluent loading of CBOD5, CBODu, NBODu,
and BOD organized by wastewater treatment type for select years from 1940 to
1996.
Data Sources and Calculations
Effluent CBOD5 loading rates were estimated based on influent CBOD5
loading rates and CBOD5 removal efficiencies (expressed as a percentage)
associated with each type of municipal wastewater treatment (see Table 2-2). In
keeping with the convention of combining primary and advanced primary treat-
ment and designating the result as "less than secondary" treatment, CBOD5
removal efficiencies for these two categories were averaged to derive a "less
than secondary" treatment removal efficiency of 42.5 percent. Likewise, CBOD5
removal efficiencies assigned to advanced secondary treatment (90 percent) and
advanced wastewater treatment (95 percent) were averaged to derive a "greater
than secondary" treatment removal efficiency of 92.5 percent. Table 2-8 presents
CBOD5 removal efficiencies by municipal wastewater treatment type and
corresponding effluent CBOD5 concentrations.
Recall that the CBOD5 removal efficiencies used in this study are percent-
ages typically assigned to NPDES permits according to the treatment process and
POTW design assumptions (USEPA, 1978; Metcalf and Eddy, 1991). Use of
"design-based" removal efficiencies may, in some cases, result in a conservative
(i.e., high) estimate of effluent CBOD5 loading. USEPA's Clean Water Needs
Surveys for the years 1976, 1978 and 1982, for example, report 41 and 64 percent
2-38
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-7. Effluent BOD loading from POTWs by wastewat
I _ T
|| Effluent CBOD5 Loading (metric tons per day)
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
6,344
7,526
6,883
6,932
6,768
5,510
4,380
4,460
4,034
3,812
Raw
4,324
4,736
1,961
1,356
663
489
252
184
0
0
• Effluent CBODu Loading (metric tons per day)
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
8,922
10,943
11,765
12,689
12,558
11,621
9,582
9,869
9,418
9,232
Raw
5,189
5,683
2,353
1,628
796
587
302
220
0
0
• Effluent NBODu Loading (metric tons per day) I
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
5,146
6,475
7,514
8,591
8,273
7,526
7,168
7,327
7,205
7,093
Raw
2,785
3,050
1,263
874
427
315
162
118
0
0
• Effluent BOD Loading (metric tons per day)U
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
Total
14,068
17,419
19,278
21,281
20,831
19,147
16,750
17,196
16,623
16,325
^^^^^^^^^^^^•^^^^^^^^
Raw
7,974
8,734
3,615
2,501
1,223
901
465
339
0
0
Less than
Secondary
1,615
2,147
3,684
3,849
4,501
2,654
1,975
2,045
1,677
1,326
Less than
Secondary
2,584
3,436
5,894
6,159
7,201
4,246
3,160
3,272
2,683
2,122
Less than
Secondary
1,248
1,660
2,847
2,975
3,500
2,924
2,167
1,787
1,465
1,159
Less than
Secondary
3,832
5,095
8,740
9,134
10,701
7,171
5,327
5,059
4,147
3,281
er treatment typ
REATMENTTYPI
Secondary
405
642
1,239
1,724
1,536
1,596
1,539
1,570
1,670
1,651
Secondary
1,150
1,825
3,518
4,897
4,363
4,533
4,371
4,460
4,743
4,688
Secondary
1,113
1,765
3,404
4,738
4,222
3,401
3,693
4,315
4,589
4,536
Secondary
2,262
3,590
6,922
9,635
8,585
7,934
8,064
8,774
9,332
9,224
e, 1940-1996.
Greater than
Secondary
0
0
0
2
68
771
614
661
687
835
Greater than
Secondary
0
0
0
6
198
2,255
1,749
1,918
1,993
2,422
Greater than
Secondary
0
0
0
4
125
886
1,145
1,107
1,151
1,399
Greater than
Secondary
0
0
0
11
322
3,141
2,894
3,025
3,144
3,821
I
............... I
On-Site
NA
NA
NA
NA
0
0
0
0
0
0
On-Site
NA
NA
NA
NA
0
0
0
0
0
0
On-Site
NA
NA
NA
NA
0
0
0
0
0
0
On-Site
NA
NA
NA
NA
0
0 1
0 1
0 1
0 1
— LI
2-39
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-8. CBOD5 removal efficiencies by municipal wastewater treatment type
and corresponding effluent CBOD5 concentrations.
I Municipal Wastewater Treatment Type 1
Raw
Less than
Secondary3
Greater than
Secondary Secondary11
CBOD5 removal efficiency (%)
CBOD5 cone, in effluent (mg/L)
0.0
21 5C
425
123.6
85.0
32.3
92.5
16 1
a Primary and advanced primary wastewater treatment.
b Advanced secondary and advanced wastewater treatment.
c Equivalent to CBOD cone, in (untreated) influent
CBOD5 removal efficiency for primary and advanced primary facilities, respec-
tively. These same reports present removal efficiencies for secondary (82 to 86
percent), advanced secondary (89-92 percent), and advanced wastewater
treatment (87 to 94 percent) either in the range or very near to the range of
design-based removal efficiencies. The design-based CBOD5 removal efficien-
cies were chosen for use in this study over actual reported efficiencies because it
was assumed that a conservative approach would provide a more effective and
consistent comparison of trends for POTW BOD removal over the entire period
of record analyzed.
Effluent CBODu loading rates were estimated for each category of waste-
water treatment from effluent CBOD5 loading rates and the corresponding
CBODu/CBOD5 ratio (see Table 2-3) using Equation 2.1. CBODu removal
efficiencies for each treatment category were then computed from the influent (I)
and effluent (E) loading as:
Percent Removal Efficiency =
(I-E)
x 100
Eq. (2.5)
Table 2-9 presents the calculated CBODu removal efficiencies by municipal
wastewater treatment type and corresponding effluent CBODu concentrations.
Effluent NBODu loading rates were estimated based on influent NBODu
and NBOD removal efficiencies reported for TKN (expressed as a percentage)
Table 2-9. CBODu removal efficiencies by municipal wastewater treatment type
and corresponding effluent CBODu concentrations.
I Municipal Wastewater Treatment Type 1
Raw
Less than Greater than
Secondary3 Secondary Secondary11
CBODU removal efficiency (%)
CBODU cone, in effluent (mg/L)
0.0
258°
233
197.8
64.5
91.6
81.9
46.8
a Primary and advanced primary wastewater treatment.
b Advanced secondary and advanced wastewater treatment.
c
Equivalent to CBODu cone, in (untreated) influent
2-40
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-10. TKN and NBODu removal efficiencies by municipal wastewater
treatment type and corresponding effluent TKN and NBODu concentrations.
I Municipal Wastewater Treatment Type 1
Raw
Less than Greater than
Secondary3 Secondary Secondary13
TKN & NBODu removal efficiency (%)
TKN cone, in effluent (mg/L)
NBODu cone, in effluent (mg/L)
0.0
30.3
138.5°
22.0
23.6
108.0
36.0
19.4
88.6
80.5
5.9
27.0
a Primary and advanced primary wastewater treatment.
b Advanced secondary and advanced wastewater treatment.
c Equivalent to NBOD cone, in (untreated) influent
Table 2-11. BODu removal efficiencies by municipal wastewater treatment type
and corresponding effluent BODu concentrations.
I Municipal Wastewater Treatment Type 1
Less than Greater than
Raw Secondary8 Secondary Secondaryb
BODu removal efficiency (%)
BODU cone, in effluent (mg/L)
0.0
396. 5C
22.9
305.8
54.5
180.2
81.4
73.8
a Primary and advanced primary wastewater treatment.
b Advanced secondary and advanced wastewater treatment.
c Equivalent to BODuconc in (untreated) influent.
associated with each category of wastewater treatment. Removal efficiencies for
TKN were based on data compiled in Gunnerson et. al (1982) for primary
facilities, AMSA (1997) for secondary facilities, and AMSA (1997) and
MWCOG (1989) for advanced wastewater treatment facilities. Since NBODuis
estimated from TKN and the constant stoichiometric ratio of 4.57 g O2 (gN)"1,
removal efficiencies for TKN and NBOD have the same value for the various
u
categories of wastewater treatment. Table 2-10 presents TKN removal efficien-
cies and effluent concentrations as TKN and NBODu.
The effluent BODu loading rates were determined by adding the calculated
CBOD and NBOD loading rates. BODu removal efficiencies for each treat-
ment category were then computed from the influent (I) and effluent (E) BODu
loading rates according to Equation 2.4. Table 2-11 presents the calculated BODu
removal efficiencies by municipal wastewater treatment type and corresponding
effluent BOD concentrations.
u
Trends in Effluent CBOD5 and BODu Loading From POTWs
Figure 2-12 is a chart that compares effluent CBOD5 and BODu loading
over the same time period. Figures 2-13(a) and 2-13(b) display effluent CBOD5
and BODu loading data organized by wastewater treatment type.
2-41
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 2-12
Total effluent BODu and
CBOD5 loading, 1940 to
1996.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
Figure 2-13
Effluent loading of (a)
CBOD5 and (b) BODu from
POTWs nationwide for
select years between 1940
and 1996 organized by
wastewater treatment type.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
(a)
(b)
I
I
o>
'•&
te
o
Q
O
m
+J
0)
_3
it
111
I
c
-
I
D)
C
'•V
(O
o
O
O
CD
O
£
o>
f
o
•I
(D
£:_
O)
'•B
to
o
3
Q
O
m
LU
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
2-42
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Key observations from Table 2-7 and Figures 2-12 and 2-13 include the
following:
• Effluent BOD loading by POTWs was significantly reduced between
1968 and 1996. In 1968, 4 years before the 1972 CWA, effluent
CBOD5 and BODu loadings were 6,932 and 21,281 metric tons per day,
respectively. By 1996 CBOD5 and BODu loadings were reduced to
3,812 and 16,325 metric tons per day, respectively. This represents a 45
percent decline in CBOD5 and a 23 percent decline in BODu between
1968 and 1996. Notably, these declines were achieved even though
influent CBOD5 and BODu loading to POTWs each increased by 35
percent during the same time period!
• The proportion of effluent CBOD5 loading attributable to raw and less
than secondary wastewater treatment was reduced from about 94
percent in 1940 to 35 percent in 1996 (see Figure 2-13(a)). The propor-
tion of effluent BODu loading attributable to raw and less than second-
ary wastewater treatment was reduced from about 84 percent in 1940
to 20 percent in 1996 (see Figure 2-13(b)).
Trends in BOD Removal Efficiency
The rate of effluent BOD loading from a POTW is determined by two main
factors, the rate of influent BOD loading and the BOD removal efficiency of the
facility. Influent BOD loading, in turn, is determined by the number of people
connected to the system and the rate at which they generate and export BOD in
their wastewater flow. The analysis above indicates that tremendous progress
was achieved between 1968 and 1996 in reducing effluent BOD loading from
POTWs into the Nation's waterways. Notably, this reduction occurred at the
same time the number of people served by POTWs was increasing rapidly.
Figures 2-14 and 2-15 present influent and effluent loadings and removal efficien-
cies for CBOD5 and BODu, respectively.
Key observations from Figures 2-14 and 2-15 include the following:
• BOD removal efficiency nationwide significantly increased between
1940 and 1996. In 1940 the aggregate national removal efficiency stood
at about 33 percent for CBOD5 and 20 percent for BODu. By 1968
removal efficiencies had increased to 63 percent for CBOD5 and 39
percent for BODu. By 1996 they had further increased to nearly 85
percent for CBOD5 and 65 percent for BODJ
• The BOD removal efficiency increased substantially between 1972 and
1978, the 6-year period after the passage of the CWA (from 64 to 74
percent for CBOD5 and from 41 to 52 percent for BOD ). Between
1978 and 1996 removal efficiency increased an additional 11 percent
for CBOD5 and 13 percent for BODu. Those larger increases in BODu
removal efficiency reflect the ever-increasing role of greater-than-
secondary POTWs over this time period.
2-43
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 2-1 4
Total POTW influent and
effluent CBOD5 loading
and corresponding CBOD5
removal efficiency for
select years between 1940
and 1996.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
CD
•§
-8
.o
u>
s
o
m
o
Influent CBOD,
Effluent CBOD
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
Figure 2-15
Total POTW influent and
effluent BODu loading and
corresponding BODu
removal efficiency for
select years between 1940
and 1996.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
100
I
I
£
I
O)
0=
O
m
Influent BODU
Effluent BODU
O Removal Efficiency
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
Figure 2-16, a three-dimensional graph of the population data presented
earlier in Table 2-5 and Figure 2-9, is useful for visualizing the trends in population
served by POTW treatment type. The population served by secondary treatment
facilities declined sharply between 1968 (85.6 million) and 1978 (56.3 million) and
then leveled off at about 82 million in the 1990s. In contrast, the number of people
served by greater than secondary treatment surged between 1968 and 1978 (0.3
to 49.1 million) and then increased steadily to about 82.9 million in 1996. Unlike
secondary treatment, advanced wastewater treatment enhances biological
processes to incorporate nitrification (ammonia removal) and denitrification
(nitrate removal), thus reducing the NBOD fraction of effluent BODu loading.
2-44
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Raw
< Secondary,
Secondary^
h 90
II 80
1 70
/
I 60
1 50
I 40
I 30
20
10
0
•o
o
•o
c
si
o'
i?
I
(D
a
<
Figure 2-16
Population served by
POTWs nationwide for
select years between 1940
and 1996 organized by
wastewater treatment type.
Source: U.S. Public Health
Service Municipal
Wastewater Inventories
and USEPA Clean Water
Needs Surveys.
Future Trends in BOD Effluent Loading
The data presented in the previous sections indicate that the increase in
BOD removal efficiency between 1940 and 1996 resulted in significant reductions
in BOD effluent loading to the Nation's waterways even though the number of
people served by POTWs greatly increased. Given that the population served
by POTWs is projected to continue to increase well into the 21st century, will
the trend of effluent BOD loading reductions also continue into the future?
A preliminary examination of estimated influent and effluent BOD loadings based
on USEPA projections of facility inventory and population served for the year
2016 indicates that the answer might be "no."
Table 2-12 presents a summary of the population served, wastewater flow,
influent and effluent BOD loading rates, and BOD removal efficiencies for 1996
and corresponding projections for 2016 and 2025. Figure 2-17 is a column chart
that extends the influent and effluent BODu loading totals and POTW removal
efficiencies originally presented in Figure 2-15 into the 21st century by adding
columns for the years 2016 and 2025 to the chart. These projections are based on
the following assumptions:
USEPA Clean Water Needs Survey (USEPA, 1997) estimates that 275
million people will be served by POTWs in the year 2016. This figure is
based on middle-level population projections from the Census Bureau
(USBC, 1996) and the assumption that 88 percent of the population will
be served by POTWs in 2016. Assuming that 88 percent of the popula-
tion projected for 2025 is also served by POTWs, about 295 million
people will be served by POTWs.
Design-based BODu removal efficiency will increase from a nation-
wide average of 65 percent in 1996 to 71 percent by 2016 based on
projections of population served by the different categories of POTWs.
This removal efficiency is assumed to remain at that level through
2025.
• Influent wastewater flow will remain a constant 165 gpcd and influent
BODu concentration will remain a constant 396.5 mg/L for the projec-
tion period from 1996 to 2025.
2-45
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-1 2. 1 996 estimates and 201 6 and 2025 projections of POTW infrastructure and influent and
effluent BOD loading.
!,_ TDC ATIUICMT TVDC 1
1
Inventory of POTWs
Population of U.S. (millions)
Population served (millions)
Percent of population served
Influent wastewater flow (mgd)
Unit flow (gallons/person/day)
Influent CBOD5 loading (metric tons/day)
Influent CBODu loading (metric tons/day)
Influent NBODu loading (metric tons/day)
Influent BODu loading (metric tons/day)
Effluent CBOD5 loading (metric tons/day)
Effluent CBODU loading (metric tons/day)
Effluent NBODu loading (metric tons/day)
Effluent BODu loading (metric tons/day)
CBOD5 percent removal
CBODu percent removal
NBODu percent removal
BODu percent removal
E3H
Inventory of POTWs
Population of U.S (millions)
Population served (millions)
Percent of population served
Influent wastewater flow (mgd)
Unit flow (gallons/person/day)
Influent CBOD5 loading (metric tons/day)
Influent CBODu loading (metric tons/day)
Influent NBODu loading (metric tons/day)
Influent BODu loading (metric tons/day)
Effluent CBOD5 loading (metric tons/day)
Effluent CBODU loading (metric tons/day)
Effluent NBODu loading (metric tons/day)
Effluent BODU loading (metric tons/day)
CBOD5 percent removal
CBODu percent removal
NBODU percent removal
BODU percent removal
E?ffEl Totals Only
Inventory of POTWs
Population of U.S. (millions)
Population served (millions)
Percent of populaton served
Influent wastewater flow (mgd)
Unit flow (gallons/person/day)
Influent CBOD5 loading (metric tons/day)
Influent CBODu loading (metric tons/day)
Influent NBODu loading (metric tons/day)
Influent BODU loading (metric tons/day)
Total
16,024
263.4
189.7
72%
31 ,302
165
25,476
30,571
16,408
46,978
3,812
9,232
7,093
16,325
85%
70%
57%
65%
Total
18,303
311.5
274.7
88%
45,329
165
36,892
44,270
23,760
68,030
4,025
10,995
8,611
19,607
89%
75%
64%
71%
Total
335.1
295.5
88 2%
48,760
165
39,684
47,620
25,558
73,179
Less than Greater than
Raw Secondary Secondary Secondary On-Site
0 176 9,388 4,428 2,032
0 172 81 9 82.9 77
0 2,834 13,521 13,683 1,264
0 2,307 11,004 11,136 1,029
0 2,768 13,205 13,363 1,235
0 1,486 7,087 7,172 663
0 4,254 20,292 20,536 1,897
0 1,326 1,651 835
0 2,122 4,688 2,422
0 1,159 4,536 1,399
0 3,281 9,224 3,821
42% 85% 92%
23% 64% 82%
22% 36% 80%
23% 54% 81%
0 61 9,738 6,135 2,369
0 5.5 1023 152.7 14.2
0 910 16,883 25,200 2,337
0 740 13,740 20,509 1,902
0 888 16,489 24,611 2,282
0 477 8,850 13,209 1,225
0 1,365 25,338 37,819 3,507
0 426 2,061 1,538
0 681 5,853 4,461
0 372 5,664 2,576
0 1,053 11,517 7,036
42% 85% 92%
23% 64% 82%
22% 36% 80%
23% 54% 81%
Effluent CBOD5 loading (metric tons/day)
Effluent CBODu loading (metric tons/day)
Effluent NBODu loading (metric tons/day)
Effluent BODU loading (metric tons/day)
CBOD5 percent removal
CBODu percent removal
NBODu percent removal
BODU percent removal
Total
4,330
1 1 ,827
9,263
21,090
89%
75%
64%
71%
2-46
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Figure 2-17. POTW influent and effluent BODu loading and removal efficiency for select years between 1940 and 1996
and 2016 and 2025. Source: U.S. Public Health Service Municipal Wastewater Inventories, USEPA Clean Water Needs
Surveys and U.S. Census Population Projections.
80,000
Influent BODu
Effluent BODu
O Removal Efficiency
1940 1950 1962 1968 1972 1978 1982 1988 1992 1996
Year
Key observations from Figure 2-17 include the following:
• Population growth from 1996 to 2016 will increase influent BODu
loading nationwide to 68,030 metric tons per day, an increase of 45
percent. By 2025 influent loading will be about 73,057 metric tons per
day, a 56 percent increase from 1996.
• In spite of a projected national increase in BOD removal efficiency
from 65 to 71 percent by 2016 (a 9 percent increase), it is estimated
that the trend of decreasing effluent BODu loadings experienced in the
24 year period from 1968 to 1996 will be reversed. It is predicted that
effluent BODu loadings will increase from 16,325 metric tons per day
in 1996 to 19,606 metric tons per day in 2016, an increase of 20 per-
cent. The effluent BODu loading rate estimated for 2016 is about equal
to effluent loading rates that existed in the mid-1970s, only a few years
after the CWA was enacted!
By 2025 the projected effluent BODu loading will be 21,090 metric tons
per day, an increase of 29 percent from 1996. This rate is about equal
to effluent loading rates experienced in 1968 (21,280 metric tons per
day), the year when the discharge of oxygen-demanding material from
POTWs had reached its historical peak!
2016 2025
2-47
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
• By 2016, when the projected needs for wastewater treatment are
expected to be met (USEPA, 1997), the overall BODu removal effi-
ciency of 71 percent and increases in population will result in a 20
percent increase of effluent loads relative to the 1996 loading rate. To
maintain an effluent BODu loading rate comparable to 1996 conditions
through 2016 (i.e., "running in place"), the national aggregate removal
efficiency would have to be increased from 71 to 76 percent. This
would need to be accomplished by shifting the projected population
served from secondary to advanced secondary and advanced waste-
water treatment facilities.
The estimated projections of increasing effluent loading rates of BOD over
the next quarter-century underscore the importance of continually investing in
improvements to wastewater treatment infrastructure to maintain and improve
pollutant removal efficiencies. Without these improvements many of the environ-
mental successes of the water pollution control efforts over the past three de-
cades may be overwhelmed by the future demand from population growth. The
very real risk of losing the environmental gains achieved by federal (Construction
Grants Program), state, and local water pollution control efforts under the technol-
ogy and water quality-based effluent limit regulations of the 1972 CWA is also
documented by Jobin (1998) and the Water Infrastructure Network (WIN, 2000).
E. Comparison of Contemporary BOD5
Loadings From POTWs and Other
Point and Nonpoint Sources Based
on Estimates of Actual Loadings
The primary purpose of Chapter 2 is to examine whether there was a
significant reduction in effluent BOD loading to the Nation's waterways after the
technology-based and water quality-based treatment provisions of the CWA were
implemented. To fully address this subject, however, it is important to recognize
the following:
• Effluent BOD loading comes from several point and nonpoint sources
in addition to POTWs.
• BOD is only one of several contaminants that have the potential to
affect aquatic resources and the lives and livelihoods of water resource
users. Table 2-13 presents some of the concerns and conditions associ-
ated with several types of water pollutants.
This section is divided into two subsections. The first subsection briefly
describes non-POTW sources of BOD loading, including industrial wastewater
treatment facilities, combined sewer overflows (CSOs), urban stormwater runoff,
and rural nonpoint sources1 of pollution. For the purposes of this comparison,
Nonpoint source (NFS) pollution sources are sources of pollution not defined by statute as
point sources. NPS pollution results from the transport of pollutants into receiving waters via
overland flow runoff in a drainage basin. Because NPS pollution is diffuse, its specific sources
can be difficult to identify.
2-48
-------
Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-1 3. Pollutant grc
Pollutant Group
Nutrients
(nitrogen and
phosphorus)
Metals and Toxics
Organic Matter
Pathogens
Sediment
Hazardous materials
ups and related water resource issues.
Water Quality Conditions
Eutrophication
Ammonia toxicity
Anoxia/ hypoxia; oxygen depletion
Water clarity/transparency
Reduced diversity/trophic structure
Fish body burden
Shellfish body burden
Mammals body burden
Anoxia/hypoxia; oxygen depletion
Adsorption/desorption of toxic chemicals
Shellfish bed closure
Recreational beach closure
Anoxic sediments
Damage to benthic biota
Oil spills
Chemical spills
and Concerns
Nuisance algal blooms
Toxic algal blooms
Fish kills
Shellfish bed closure/loss
Loss of seagrass beds/habitat
Birds body burden
Sediment contamination
Drinking water supply
Fish kills
Drinking water supply
Habitat destruction/fish spawning
Water clarity/ transparency
Fish kills
urban stormwater runoff includes areas both outside (termed "nonpoint source")
and within (meeting the legal definition of a point source in section 502(14) of the
CWA) the NPDES stormwater permit program.
The second subsection introduces the National Water Pollution Control
Assessment Model (NWPCAM) (Bondelid et al., 1999), a tool that can be used
to estimate the water quality impact of current (ca. 1995) BOD5 effluent loadings
from point and nonpoint sources nationwide. The primary purpose of this exercise
is to compare BOD5 effluent loadings from POTWs with BOD5 effluent loadings
from other point and nonpoint sources.
Pollutant Loading From Sources Other Than
POTWs
Industrial Wastewater Treatment Facilities
Many industrial facilities discharge treated wastewater directly to surface
waters. Similar to municipal wastewater treatment, industrial wastewater treat-
ment consists of a sequence of physical, biological, and chemical processes
designed to remove pollutants that are specific to an industrial facility's manufac-
turing operations. USEPA's effluent guidelines, prepared for specific categories of
industrial groups, prescribe effluent limits in terms of the industry's output produc-
tion rate (e.g., n kilograms of pollutant discharged per 1,000 kilograms of factory
production). Table 2-14 presents median effluent concentrations for conventional
and nonconventional pollutants for the industrial categories that account for the
largest contributions to effluent loading rates for BOD5.
2-49
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 2-14. Effluent characteristics for select major industry groups. Source: Tetra Tech, 1999; NOAA, 1994.
Inorganic Organic Food Iron Pulp
Parameter Chemical Chemical and and Petroleum and
(mg/L) Products Products Feedlots Beverages Steel Refining Paper
BOD5
TOC
NH3-N
Total-N
Total-P
TSS
DO
No. of Facilities
Average Median
Major Facilities
Minor Facilities
6.5
9.4
1.3
1.9a
0.4
10.6
N/A
273
Design Flow
2.9
0.2
6.3
11.2
1.2
33.4a
N/A
11.8
N/A
232
(mgd)
2.3
1.7
6.0
N/A
0.7
28.5a
1.4
13.1
7.7
32
N/A
0.3
Note: The table presents the median value of effluent data extracted from
indicated by a, which indicates that Typical Pollutant Concentration
11.8
N/A
0.6
17.9a
6.7a
12.0
N/A
62
0.3
0.1
6.0
N/A
1.0
2.9a
N/A
9.9
6.6
186
3.9
0.2
8.8
12.0
2.0
N/A
N/A
12.9
N/A
203
3.0
0.3
24.5
N/A
1.2
1.4a
0.6
29.4
5.8
309
5.0
0.8
PCS for the period 1991 to 1998 except where
(TPC) effluent data compiled by NOAA (1994) are used.
In contrast to direct industrial dischargers, industrial facilities can also
discharge wastewater to sanitary sewer systems, where it mixes with domestic
sources of wastewater (indirect industrial dischargers). This wastewater often
contains a variety of metals, organic chemicals, and oily wastes that are not
common to domestic sources of wastewater. Because of the high degree of
variability, most municipal treatment systems are not designed to treat a vast array
of industrial wastes. Consequently, these wastes can interfere with the operation
of treatment plants, contaminate receiving waterbodies, threaten worker health
and safety, and increase the cost and risks of sludge treatment and disposal.
Using proven pollution control technologies and practices that promote the reuse
and recycling of material, however, industrial facilities can provide "pretreatment"
by removing pollutants from their wastewater before discharging to the municipal
wastewater system. In addition to the categorical standards for pretreatment
established as part of the industrial effluent guideline process, local pretreatment
limits are enforced by various municipal facilities to protect treatment processes,
worker health and safety, and equipment. USEPA's National Pretreatment
Program, a cooperative effort of federal, state, and local officials, is fostering this
practice nationwide.
2-50
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Combined Sewer Overflows
In many older cities of the United States, urban sewer systems were
originally designed to convey both raw sewage and storm water runoff collected
during rainstorms. These combined sewer overflow systems were also explicitly
designed to discharge (overflow) the mixture of raw sewage and storm water into
the river if a heavy rainstorm exceeded the hydraulic capacity of the combined
sewer system. As a vestige of public works practices from approximately 1850 to
1900, about 880 cities mostly in the central and northeastern states have combined
sewer systems that continue to function in this manner (USEPA, 1997). Table
2-15 presents characteristic discharge concentrations of conventional and
nonconventional pollutants in combined sewer overflows (CSOs).
In addition to raw sewage, a CSO system can discharge pretreated indus-
trial waste and street debris washed off during a storm. Although pollutant loading
from CSO systems is intermittent, occurring only under heavy rainstorm condi-
tions, the high loading rates of sewage from CSO outlets frequently result in the
closure of recreational beaches and shellfish beds to protect public health. Dis-
charges from CSOs also are associated with depressed oxygen levels in poorly
flushed waterbodies, accumulation of organics in sediments, and generally noxious
conditions and odors.
National assessments show that the relative significance of annual loading of
BOD5 from CSO systems is about the same as the effluent loading from second-
Table 2-15. Effluent characteristics of urban runoff and CSOs.
Parameter
BOD5 (mg/L)
CBODu/BOD6
TSS (mg/L)
TKN (mg/L)
NH3-N (mg-N/L)
NO2-N +NO3-N (mg-N/L)
Total N (mg-N/L)
Total P (mg-P/L)
Total Lead (mg/L)
Total Conforms (MPN/100 m/L)
Urban Runoff
Range"'"
10-13
ND
141-224
1.68-2.12
ND
0.76-0.96
3-10
0.37-0.47
161-204
103-108
CSO
Range0" (event mean)
60-200 (115)
ND (1.4)e
100-1100 (370)
ND (6.5)
ND (1.9)
ND (1.0)
3-24 (7.5)
1-11 (10)
ND (370)
10M07 (ND)
NOTES: ND = Nodata
a Range of urban runoff concentrations reflects variability of coefficient of variation of
event mean concentrations for median urban sites. Data from USEPA (1983) presented in
Novotny and Olem (1994) (Table 1.3, p.36).
b Range of urban runoff concentrations for total N and total conforms from Novotny and
Olem (1994) (Table 1.3, p. 36).
0 Range of CSO concentrations for BOD5, TSS, total N and total conforms from Novotny and
Olem (1994) (Table 1.3, p36).
" Mean CSO concentrations of BOD5, TSS, and total lead from USEPA (1978) presented in
Novotny and Olem (1994); median CSO concentrations of nitrogen constituents from
Driscoll (1986); mean CSO concentration of total phosphorus from Ellis (1986).
8 CBOD,/BOD5 ratio from Thomann and Mueller, 1987.
2-51
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
ary wastewater treatment facilities in the same urban area. In contrast to BOD5,
annual loading of suspended solids and lead is about 15 times greater from CSO
systems than from secondary wastewater treatment facilities. Annual loading
rates of total nitrogen and phosphorus from CSOs, however, are only about one-
fourth (total N) and one-seventh (total P) of the annual loads contributed by
secondary facilities (Novotny and Olem, 1994).
Urban and Rural Nonpoint Sources
Organic and inorganic materials, both naturally occurring and related to
human activities, are transported to waterbodies within a drainage basin by
surface runoff over the land as nonpoint, or diffuse, sources of pollutants. The
magnitude and the timing of nonpoint pollutant loads are dependent on many
complex, and interacting, processes within a drainage basin. In contrast to the
relatively continuous input of pollutants from point sources, the timing of loading
from diffuse sources is highly variable with intermittent loading related primarily to
meteorological events (storms and snowmelt). The magnitude of pollutant loads is
dependent on the area of the drainage basin, the characteristics of land uses,
including ground cover, and distribution of the volume of precipitation between
infiltration into shallow aquifers and surface runoff into streams and rivers.
Within a watershed undisturbed by human activities, naturally occurring
biogeochemical processes account for the continual cycles of organic and inor-
ganic materials (as uncontrollable nonpoint source loads) transported from the
land to rivers, lakes, and estuaries, with eventual discharge of these materials to
the coastal ocean. Since it is the uses of the land and the associated activities that
occur on the land within a drainage basin that contribute anthropogenic organic
and inorganic materials to surface waters, nonpoint source loading rates have
been related to the type of land use (Table 2-16). The most critical factor, how-
ever, in understanding the management of nonpoint source loading is characteriz-
ing the transition from one land use to another (e.g., forest to agriculture, agricul-
ture to suburban/urban).
Table 2-16. Nonpoint s<
Parameter
BOD5ab
TSS a'b
Total N b'c
Total P b'c
Durce runoff export
Urban
34-90
3,360-672
7.8-11.2
1.6-3.4
coefficients for g
Agriculture
26
1,600
16.5
1.1
eneral land uses
Forest
5
256
2.9
0.2
Units are kg/hectare-year
a Export coefficients for BOD5 and TSS for agriculture and forest categories from Thomann
and Mueller (1987).
b Range of export coefficients for urban land use categories I, II, and III from PLUARG
studies (Marsalek, 1978) presented by Novotny and Olem (1994) (Table 8.2, p. 449).
0 Mean export coefficients for total N and total P for mixed agricultural and forest land uses
from Reckhow et al. (1980).
2-52
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Beginning with the four natural land classifications (arid lands, prairie,
wetland, and woodland), the transformation of a watershed's land uses progresses
over many years through several intermediate stages of development to a fully
developed urban-industrial watershed (Novotny and Olem, 1994). With the
irreversible transformation to the endpoint of urban-industrial land uses of a
watershed, the emphasis in water quality management needs to incorporate
strategies for control of both nonpoint sources of runoff and the point source
discharges within the "urban-industrial" water cycle. In contrast to the control
strategy for point sources (build a wastewater treatment facility) as the most
effective technology for removal of pollutants from a point source waste dis-
charge, the reduction of nonpoint source loading of pollutants is focused on the
design and implementation of "best management practices" to control, and
manage, land use activities and surface runoff. As with urban runoff control
measures, the technical aspects of the numerous practices available for control-
ling nonpoint source runoff from forest, agricultural, and other rural land uses are
presented in detail by Novotny and Olem (1994).
As part of its public works infrastructure, practically every town and city in
the nation has an urban stormwater sewer system designed to collect and convey
water runoff from rainstorms and snowmelt. Depending on the development
characteristics of an urban area, stormwater runoff can result in significant
intermittent loading of pollutants to surface waterbodies. Based on findings from
the National Urban Runoff Project (NURP) conducted by USEPA from 1978 to
1983, USEPA (1983) concluded that urban runoff accounted for significant wet
weather loading to the Nation's surface waters of pathogens, heavy metals, toxic
chemicals, and sediments. The origins of the diffuse discharges of these pollutants
include contaminants contained in wet and dry atmospheric deposition, erosion of
pervious lands, accumulation of debris on streets, traffic emissions, and washoff
of contaminants from impervious land surfaces. Table 2-15 presents typical
discharges of conventional and nonconventional pollutants in urban runoff.
Estimates of Contemporary (ca. 1995) BOD5
Loading Using the National Water Pollution
Control Assessment Model (NWPCAM)
The NWPCAM is a national-scale water quality model designed to link point
and nonpoint source loadings and resultant calculated in-stream concentrations of
CBOD5, CBODu, DO, TKN, total suspended solids, and fecal coliform bacteria
with a "water quality ladder" of beneficial uses (Carson and Mitchell, 1983). The
framework for the model is EPA's Reach File Version 1 (RF1) national database
of streams, rivers, lakes, and estuaries and uses mean summer streamflow data to
characterize the steady-state loading, transport, and fate of water quality constitu-
ents. Presented for comparison purposes is current (ca. 1995) BOD5 loading
information derived using available NWPCAM national data for municipal and
industrial discharges, CSOs, and urban1 and rural nonpoint sources.
1 For purposes of this comparison, urban stormwaler runoff includes areas both outside (termed
"nonpoint sources") and within (meeting the legal definition of a point source in section 502(14)
of the CWA) the NPDES stormwater permit program.
2-53
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
BOD5 Loading from Municipal and Industrial Sources
The input data used to estimate municipal and industrial effluent loading of
BOD5 within the NWPCAM come from USEPA's Permit Compliance System
(PCS), the Clean Water Needs Survey (CWNS) databases, and default assump-
tions derived from the literature. The PCS database contains discharge monitoring
data for major POTWs and industrial dischargers (facilities with a discharge
greater than 1 mgd). The CWNS database provides a more comprehensive
database of all POTWs and generally reliable population, flow, and treatment level
information. Less confidence is placed on the effluent concentration data reported
in the CWNS database. Therefore, when actual discharge data were available
from PCS, those data were used. PCS data were also used to develop default
effluent concentrations to apply when a facility's actual concentration was not
available or was outside normal ranges expected for a given level of treatment.
Municipal
Table 2-17 presents a compilation of characteristic effluent concentrations
of conventional and nonconventional pollutants used in NWPCAM for different
types of municipal POTWs. The data sets extracted from USEPA's PCS and
CWNS databases are supplemented by influent and effluent data taken from the
literature (e.g., AMSA, 1997; Metcalf and Eddy, 1991; Clark et al., 1977; Leo et
al.; 1984; Thomann and Mueller, 1987).
A total of 1,632 of the 2,111 hydrologic catalog units in the contiguous United
States are subject to municipal effluent loading. Figure 2-18 presents distributions
of municipal BOD5 loading by percentile of catalog units with nonzero municipal
loads according to (a) loading rate and (b) fraction of total municipal loading.
Figure 2-19 presents a map showing the magnitude of municipal effluent loading
of BOD5 aggregated for the 1,632 catalog units with nonzero municipal loads.
Figure 2-20 displays the proportion of the total nonpoint and point sources load
contributed by municipal waste loads.
Key observations from Figures 2-18 through 2-20 include the following:
• Less than 1 percent of the 1,632 catalog units subject to municipal
loading receive effluent BOD5 loading at a rate greater than 25 metric
tons/day (Figure 2-18a). About 20 percent of the catalog units account
for about 90 percent of the total municipal BOD5 loading to the
Nation's waterways (Figure 2-18b).
Relatively low municipal BOD5 loading rates (less than 0.5 metric ton/
day) characterize many of the catalog units within the western and
central portions of the contiguous 48 states.
Higher rates of municipal loading (0.5 to 5 metric tons/day) are charac-
teristic of the Mississippi River valley and the Northeast, Midwest, and
Southeast. The highest loading rates (> 25 metric tons/day) are for
major urban centers, including New York, Boston, Los Angeles, San
Diego, Dallas-Ft. Worth, Detroit, and San Francisco.
2-54
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-17. Effluent characteristics for POTWs.
Parameter
(mg/L)
(Influent)
Raw
Primary
Advanced
Primary
Secondary
Advanced
Advanced Wastewater
Secondary Treatment
BOD.
Mean
% Removal
Reference/Notes
205.0
0
a,/
143.5
30
b
102.5
50
C
16.4
92
a
6.2
97
a,d
4.1
98
a, d
CBODJCBOD5
Mean
Reference/Notes
TSS (mg/L)
Mean
% Removal
Reference/Notes
NH3-N (mg-N/L)
Mean
% Removal
Reference/Notes
TKN (mg-N/L)
Mean
% Removal
Reference/Notes
Total N (mg-N/L)
Mean
% Removal
Reference/Notes
Total P (mg-P/L)
Mean
% Removal
Reference/Notes
DO (mg/L)
Mean
Reference/Notes
Total Organic Carbon (mg/L)
Mean
% Removal
Reference/Notes
1.2
e
215
0
a,/
18.0
0
a
30.0
0
a
30.0
0
9
6
0
a
4.1
/
148.6
0
9
1.6
f
107.5
50
b
14.4
20
b
23.4
22
b
23.4
22
h
5.2
13
b
4.3
y
107.5
28
b, k
1.6
f
64.5
70
c
14.4
20
b
23.4
22
b
23.4
22
h
5.2
13
b
4.3
1
76.8
48
/f
2.84
f
17.2
92
a
12.2
32
a
16.5
45
a
18.3
39
a
2.5
58
a
6.6
/
21.8
85
b,k
2.84
f
6.5
97
a,d
3.4
81
a,d
12.9
57
a,d
18.4
39
a,d
0.4
94
a,d
6,6
y
8.2
94
k
3.0
f
4.3
98
a,d
2.0
89
a,d
3.6
88
a, of
14.4
52
a,d
0.4
94
a,d
7.1
y
5.8
96
/r
References/Notes
a. AMSA, 1997. Influent concentration, percent removal, and TKN:TN, NH3:TKN, and P04:TP ratios for secondary, advanced
secondary, and advanced wastewater treatment, b. Gunnerson et al., 1982. c. NRC, 1993. Percent removal for advanced
primary with "low dose chemical addition." rf. MWCOG, 1989. Percent removal and TKN:TN, NH3:TKN, and PO4:TP ratios for
advanced secondary, and advanced wastewater treatment, e. Thomann and Mueller, 1987. f. Leo et al., 1984. g. Metcalf
and Eddy, 1991. TKN:TN, NH3:TKN, and PO4:TP ratios of influent concentration for "medium" strength wastewater, raw TOC
influent concentration based on BOD6, CBOD^BOD,, oxygen:carbon, and ratios of C:DW. h. ICPRB, 1991. TKN.TN, NH3:TKN,
and P04:TP ratios of effluent concentration for primary, advanced primary, and secondary treatment. I. Assume 50 percent
saturation at 25 °C and 50 mg/L chlorides at sea level. ]. Tetra Tech, 1999. Mean effluent oxygen concentrations based on
PCS database for primary, secondary, and advanced treatment. Mean influent concentrations for BOD5 (207 mg/L) and TSS
(209 mg/L) from CWNS database consistent with influent data from AMSA (1997). k. Effluent TOC concentration computed
from effluent BODS, CBODU:BOD6, oxygenxarbon ratio and assumption that 80 percent of organic carbon is accounted for by
BOD6 measurement. Removal efficiencies computed for primary and secondary treatment are consistent with data from
Gunnerson et al., 1982.
2-55
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 2-18
Distribution of municipal
BOD5 loading by percentile
of catalog units subject to
municipal loading
(N=1,632) as (a) metric
tons/day and (b) fraction of
total municipal loading
rate.
Source: Bondelid et al.,
1999.
(a)
-§ 300-
^/5
S 250 H
,§_ 200-1
O>
i 150-1
re
o
10
Q
O
CD
a>
3
E
LLJ
100-
50-
0 0.5 1 1.5 2 2.5 3 3.5
Percentile of Catalog Units
4.5
(b)
0)
O)
re
£
0)
H
0)
0.
•o
re
o
in
Q
O
CO
o>
i
10 15 20 25 30 35 40 45
10
Percentile of Catalog Units
The municipal wastewater component of total point and nonpoint
source load of BOD5 tracks closely with the results of the loading
magnitude calculation. The municipal wastewater component is highest
around major urban centers and lowest in the western and central
portions of the contiguous 48 states.
2-56
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
IfGBVD
CZDO metric tens/d£y
Bi 0- 0.5 metrictonsWay
0.5-5matrictonsWay
I 15-10 mstrictons'day
10-25 metric tons'day
^•> 25 metric tore/day
Figure 2-19
Municipal wastewater
loading of BOD5 ca. 1995
by catalog unit (metric tons
per day).
Source: Bondelid et al.,
1999.
Figure 2-20
Municipal wastewater
component of total point
and nonpoint source
loading of BOD5 ca. 1995
by catalog unit (percent of
total).
Source: Bondelid et al.,
1999.
2-57
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Industrial
Similar to the two municipal maps, Figure 2-21 presents the magnitude of the
industrial effluent loading of BOD5 aggregated for a total of 1,504 catalog units
with nonzero industrial loads. Figure 2-22 displays the proportion of the total
nonpoint and point sources load accounted for by industrial waste loads.
Key observations include the following:
• Relatively low industrial BOD5 loading rates (< 0.5 metric ton/day)
characterize many of the catalog units in the western and central
portions of the 48 states.
• Higher rates of industrial loading (0.5 to 5 metric tons/day) are charac-
teristic of the Mississippi River valley, the Northeast, Midwest, and
Southeast. The highest loading rates (> 25 metric tons/day) are indi-
cated for major urban industrial watersheds including Austin-Oyster in
Texas, East-Central in Louisiana, Buffalo-San Jacinto and Galveston
Bay, and the Locust River, Upper Black Warrior, and Middle Coosa
basins in Alabama.
• Industrial loads are the dominant component (>75 percent) of the total
point and nonpoint source load in many catalog units associated with
major urban-industrial areas, particularly in the Southeast. Although not
shown, the frequency distributions of industrial BOD5 loads (as a
percentile of catalog units with nonzero industrial loads) are very similar
to those presented for municipal BOD5 loads.
BOD5 Loading From CSOs
Effluent loadings for CSOs were based on an analysis performed in support
of the 1992 Clean Water Needs Survey (CWNS) (Tetra Tech, 1993) and subse-
quently adopted for the NWPCAM. During this 1992 CWNS, it was estimated
that there were approximately 1,300 CSO facilities in the United States (USEPA,
1993). The number of facilities was substantially reduced to 880 during the 1996
CWNS.
The effluent loading for CSOs used in the NWPCAM is based on comput-
ing a pulse load based on the runoff volume and pollutant load associated with a
5-year, 6-hour storm event. Runoff was computed as a function of the combined
sewer system's population, service area, and imperviousness. For the purposes of
the NWPCAM, the pollutant loading used in the model was estimated to yield a
national BOD5 loading of 15 metric tons/day (Bondelid et al., 1999). As expected,
most of the CSO loading is accounted for by older cities in the New England,
Middle Atlantic, Great Lakes, Ohio River, and Upper Mississippi basins.
2-58
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
l£GBf)
CHOmeWc tens/day
• 0- 0.5 metrictoiWday
ESBjaS-SmetictonsftJay
[H]5-10mB(ric1cns*Jay
10-25 metric tons/day
I > 25 nBlric tore/day
Figure 2-21
Industrial wastewater
loading of BOD,
by catalog unit (metric tons
per day).
Source: Bondelid et al.,
1999.
Figure 2-22
Industrial wastewater
component of total point
and nonpoint source
loading of BOD5 ca. 1995
by catalog unit (percent of
total).
Source: Bondelid et al.,
1999.
2-59
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
BOD5 Loading From Urban Stormwater Runoff and Rural
Nonpoint Sources
Nonpoint source BOD5 loading data were developed on a county-level basis
by Lovejoy (1989) and Lovejoy and Dunkelberg (1990), with urban Stormwater
runoff and rural runoff loadings reported separately. These values were con-
verted into loadings allocated to each catalog unit in the contiguous 48 states
based on the proportion of a county's area in a given catalog unit. For the
NWPCAM, the rural loadings were disaggregated based on stream length in a
given county while urban loadings were disaggregated based on stream length and
population associated with a given stream.
Using the loading data compiled for the NWPCAM, the national catalog
unit-based distributions of urban Stormwater and rural BOD5 loading are pre-
sented in Figures 2-23 and 2-24 (urban) and Figures 2-25 and 2-26 (rural). The
map sets present both the magnitude of the loading rate (as metric tons per day)
and the percentage of the total point and nonpoint source load accounted for by
the urban and rural runoff contributions, respectively.
Key observations include the following:
• With the exception of urban areas on the west coast and in the Mid-
west and Northeast, low loading rates (< 0.5 metric tons/day) charac-
terize most of the Nation's watersheds for urban runoff loads.
• In urban areas, loading rates are typically less than 5 metric tons/day,
accounting for about 25 to 75 percent of the total point and nonpoint
source BOD5 load discharged to a catalog unit.
• Rural loading rates of BOD5 are characterized by a distinctly different
geographic distribution, with the highest rates (> 25 metric tons/day)
estimated for the upper Missouri basin. Intermediate loading rates of 5
to 25 metric tons/day of BOD5 characterize rural runoff in the Mis-
souri, Upper Mississippi, and Ohio river basins. The lowest rates (< 0.5
metric tons/day) are estimated for the coastal watersheds of the east
coast and Gulf of Mexico and the arid areas of the western states.
• Rural nonpoint source loads of BOD5 are the dominant component
(> 75 percent) of total point and nonpoint source loads in vast areas of
the Nation, principally west of the Mississippi River and in the Ohio
River Basin.
• The geographic distribution of relatively low contributions of rural
runoff (< 25 percent) is consistent with the locations of large urban-
industrial areas (e.g., New York, Boston, Miami, New Orleans, Chi-
cago, Seattle, San Francisco, Los Angeles).
1 For purposes of this comparison, urban Stormwater runoff includes areas both outside (termed
"nonpoint sources") and within (meeting the legal definition of a point source in section 502(14)
of the CWA) the NPDES Stormwater permit program.
2-60
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
IEGBJD
I 10 metric tons/day
•H 0- 0.5 metric tonsfaay
05 - 5 metrictonsWay
I l5-10metrictonsMay
10 -25 metric tore/day
I > 25 metric tons/day
Figure 2-23
Urban nonpoint loading of
BOD5 ca. 1995 by catalog
unit (metric tons per day).
Source: Bondelid et at.,
1999.
Note: Urban stormwater runoff includes areas both outside and within the
NPDES stormwater permit program.
Figure 2-24
Urban nonpoint
component of total point
and nonpoint source
loading of BOD5 ca. 1995
by catalog unit (percent of
total).
Source: Bondelid et ai,
1999.
Note: Urban stormwater runoff includes areas both outside and within the
NPDES stormwater permit program.
2-61
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
LEG00J
dUO metric tens/day
Has 0- 0.5 metric taWday
0.5 - 5 metrictonsWay
I 15-10 metric tons/day
EZ3 10-25 metric tons/day
M> 25 metric tors/day
Figure 2-25
Rural nonpoint loading of
BOD5 ca. 1995 by catalog
unit (metric tons per day).
Source: Bondelid et al.,
1999.
Figure 2-26
Rural nonpoint component
of total point and nonpoint
source loading of BOD5 ca.
1995 by catalog unit
(percent of total).
Source: Bondelid et al.,
1999.
2-62
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Comparison of Point and Nonpoint Sources of
BODK at the National Level
i)
From a national perspective, BOD5 loading from municipal facilities cur-
rently (ca. 1995) accounts for only about 38 percent of total point source loadings
and only 21 percent of total loadings (point and nonpoint). Industrial facilities
(major and minor) account for about 62 percent of total point source BOD5
loadings and 34 percent of total BOD5 loadings. Rural nonpoint source loads
account for about 40 percent of the total BOD5 loading rate. Urban stormwater
runoff and CSOs, although significant in most urban waterways, account for a
small share (5 percent) of the total nationwide load (Bondelid et al., 1999).
Based on this analysis of contemporary sources of loading of BOD5,
continued maintenance and improvement of water quality conditions of the
Nation's surface waters will clearly require an integrated, watershed-based
strategy, such as that presented in the USEPA's (1998) Clean Water Action
Plan, including the appropriate management of point and nonpoint sources of
BOD5 and other pollutants (e.g., nutrients, suspended solids, toxic chemicals,
pathogens).
F. Investment Costs for Water Pollution
Control Infrastructure
The analysis presented in Section D indicates that nationwide effluent BODu
loadings from POTWs were reduced by 23 percent between 1968 and 1996.
Examination of historical trends in industrial wastewater loads also suggests
substantial declines in BOD loads from industrial point sources have been
achieved since the early 1970s (see Luken et al., 1976). Declines can be credited
to industrial pretreatment programs, upgrades of industrial wastewater treatment
as required by the NPDES permit program, abandonment of obsolete manufactur-
ing facilities in the Midwest and Northeast "rustbelt" (Kahn, 1997), and improved
efficiency in industrial water use (Solley et al., 1998). The purpose of this section
is to provide an overview of the costs of implementing public and private water
pollution control programs.
The Construction Grants Program
The Water Pollution Control Act of 1956 was significant because it both
established and funded a grant program for the construction of POTWs for the
purpose of ensuring the implementation of adequate levels of municipal waste
treatment as a national policy for water pollution control. Following the 1956
Amendments, however, federal funding ($5.1 billion allotted from 1957 to 1972)
accounted for only a small portion of the total construction costs for municipal
facilities (FWPCA, 1970). The CWA made it a national policy to provide federal
grants to assist in the upgrade and construction of municipal wastewater facilities.
The 1972 act authorized $5.0 billion in federal spending for fiscal year 1973, $6.0
billion for fiscal year 1974, and $7.0 billion for fiscal year 1975. Under the re-
vamped Construction Grants Program, the federal share was 75 percent of cost
from fiscal years 1973 to 1983, and 55 percent thereafter.
2-63
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
USEPA's Grants Information and Control System (GICS) database is the
central repository of Construction Grants Program data. For the following finan-
cial analysis, grant awards in the GICS database were indexed to constant 1995
dollars using the Chemical Engineering Plant Cost Index (CE, 1995) for the
purpose of providing a suitable indicator of the inflation of wastewater treatment
facility construction costs.
National Summary
During the 25-year period from 1970 to 1999, the Construction Grants
Program distributed a total of $61.1 billion in federal contributions ($96.5 billion as
constant 1995 dollars) to municipalities for new construction and upgrades of
POTWs to secondary and greater levels of wastewater treatment (Figure 2-27).
An additional $16.1 billion (capitalization) in federal contributions was also distrib-
uted to the states through the Clean Water State Revolving Fund (CWSRF)
Program from 1988 through 1999 (Figure 2-27). Additional state match, state-
leveraged bonds, loan repayments, and fund earnings increased CWSPvF assets
by $18.4 billion. Since 1988, therefore, the CWSRF loan program assets have
grown to over $30 billion, and they are funding about $3 billion in water quality
projects each year.
Figure 2-27
Annual funding provided by
USEPA's Construction
Grants and CWSRF
programs to local
municipalities for
improvements in water
pollution control
infrastructure as (a) annual
allotments for each
program and (b)
cumulative funding from
both programs from 1970
to 1999.
Source: USEPA GICS
database and CWSRF
Program.
(a)
n
o
O
0>
7-
6-
5-
4-
3-
2-
1-
0
Construction Grants
CWSRF
1970 1975 1980 1985 1990 1995
Year
2000
-v 70-
c
.0
§ 60-
•Q
^ 50-
0 40-
S 30-
8 20-
- 10-
n
• Construction Gr?
m CWSRF
nts
,ll
llll
..llllll
-
-
^
S
1970 1975 1980 1985 1990 1995
Year
2000
05
05
O5
<5
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O o
I I
o =
05-°
05 i-
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2-64
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
0 10 20 30 40 50 60 70 80 90 100
Percentile of Catalog Units
Figure 2-28
Cumulative funding of
Construction Grants
Program awards as a
percentile of 2,111 catalog
units.
Source: USEPA GICS and
reach file Version 1 (RF1)
databases.
Summaries by Catalog Unit
Awards data extracted from the GICS database were assigned to each of
the 2,111 catalog units of the 48 contiguous states by matching city names and
counties with corresponding catalog units. Of the total amount of funding awards
in the GICS database ($61.1 billion), only a small fraction (less than 1 percent) of
the awards could not be assigned to a specific catalog unit. In addition, approxi-
mately 2 percent of the GICS funding was awarded to watersheds located outside
the 48 contiguous states. (This accounts for the discrepancy between a total
national investment of $61.1 billion and the investment of $59.2 billion that was
allocated to the 48 contiguous states.)
Figure 2-28 presents the cumulative distribution of the GICS funding awards
(total $59.2 billion) as a percentile of the 2,111 catalog units within the contiguous
48 states. Twenty percent of the catalog units account for about 88 percent of the
funding. There is also a relationship between the municipal BOD5 loading rate
(ca. 1995) and the Construction Grants award allocated to each catalog unit.
Increased municipal loading rates related to larger facilities resulted in increased
grant awards from the Construction Grants Program (Figure 2-29).
_- 10,000,000
10 1,000,000-
O) J
CO
•o
c
LL.
in
O
o
o
O
100,000-
10,000-
1,000-
100-
10
1 10 100 1,000 10,000 100,000 1,000,000
Municipal BODs Loading for Catalog Unit (kg/day)
Figure 2-29
Relationship of municipal
BOD5 loading rate ca. 1995
and EPA Construction
Grants Program awards by
catalog unit.
Source: USEPA GICS
database and Bondelid et
al., 1999.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Other Investment Costs for Water Pollution Control
Infrastructure
In addition to the federal expenditures through the Construction Grants
Program, state and local governments and private industries have made significant
investments to comply with the water pollution control requirements of the CWA
and other state and local environmental legislation. On a nationwide basis, actual
expenditure data compiled by the U.S. Department of Commerce, Bureau of
Economic Analysis in the annual Pollution Abatement Cost Expenditures
(Vogan, 1966) document a cumulative public and private sector capital expendi-
ture of approximately $200.6 billion and an additional $210.1 billion as operating
expenditures (capital and operation and maintenance costs as current year
dollars) for water pollution control activities during the period from 1972 through
1994 (Figure 2-30).
As shown in Table 2-18, current year dollars compiled in the annual survey
have been indexed to constant 1995 dollars using the Chemical Engineering
Plant Cost Index for capital costs and the consumer-based Gross Domestic
Product for operating costs as appropriate indices. The Construction Grants
Program provided federal grant support to local municipalities that amounted to
almost one-half of the public sector costs and about one-third of the total public
and private sector capital investment for water pollution control.
Figure 2-30
Annual water pollution control expenditures (as current year dollars) by the public and private sectors for capital and
operations and maintenance costs from 1972 through 1994. Source: Vogan (1996).
35-,
D O & M - Private
Capital - Private
O & M - Public
Capital - Public
1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994
Year
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Table 2-18. National public and private sector investment in water pollution control infrastructure, 1956-1994.
EPA EPA Public Private Public + Private
Construction Grants CWSRF Sector Sector Sectors
(1956-1972) (1970-1995) (1988-1999) (1972-1994) (1972-1994) (1972-1994)
Current Year Dollars
Capital $5.1 $61.1 $16.2 $132.4 $68.2 $200.6
O&M n/a n/a n/a $121.2 $88.9 $210.1
Totals $5.1 $61.1 $16.2 $253.6 $157.1 $410.7
Equivalent as Constant 1995 Dollars
Capital $14.3 $96.5 n/a $178.9 $93.5 $272.4
O&M n/a n/a n/a $175.5 $128.1 $303.6
Totals $14.3 $96.5 n/a $354.4 $211.6 $576.0
Sources:
1. EPA Construction Grants Program (1956-1972): data obtained from EPA-OWM files compiled by R.K. Bastian, March 1992.
2. EPA Construction Grants Program (1970-1995): data obtained from EPA GICS database, August 1995.
3. EPA Clean Water State Revolving Fund (CWSRF) (1988-1999): data from EPA-OWM files by R.K. Bastian, April 2000.
4. Public and private sector (1972-1994): Data from Vogan (1996). Data obtained from T. Gilliss, EPA-OPPE, 1997.
5. Current year dollars adjusted to equivalent constant 1995 dollars. Plant Cost Index obtained from Chemical Engineering
(CE, 1995) for capital expenditures. Gross Domestic Product for O&M costs obtained from Council of Economic Advisors
(1997).
Future Infrastructure Needs
USEPA (1997) estimates that by 2016 approximately 2,400 new facilities
with secondary or greater than secondary levels of treatment will be needed to
service an additional 85 million people (a 45 percent increase of total population).
Further, during that time period the Agency estimates that 115 of the approxi-
mately 176 POTWs currently providing less than secondary treatment will
upgrade their facilities to meet the minimum technology requirements of second-
ary treatment under the CWA. USEPA estimates the costs for POTW construc-
tion and upgrades to be $75.9 billion (indexed to constant 1996 dollars).
Further, USEPA plans to put more emphasis on "wet weather" sources of
pollution, including CSOs and storm water drainage from agricultural, silvicultural,
city, and suburban lands. USEPA (1997) has estimated these associated federal
costs to include the following:
• $44.7 billion (indexed to constant 1996 dollars) to meet infrastructure
needs associated with CSOs.
• $7.4 billion (indexed to 1996 dollars) to meet the Clean Water State
Revolving Fund (CWSRF)-eligible portion of the costs that the munici-
pal separate storm sewer systems are expected to incur for the devel-
opment and implementation of a stormwater management program in
response to the Phase I NPDES stormwater program regulations.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
$3.8 billion (indexed to 1996 dollars) to meet the CWSRF-eligible
projects related to cropland, pastureland, and rangeland.
$2.1 billion (indexed to 1996 dollars) to meet the CWSRF-eligible
projects related to confined animal facilities with fewer than 1,000
animal units.
$3.5 billion (indexed to 1996 dollars) to meet the CWSRF-eligible
projects related to silviculture.
G. Summary, Conclusions, and Future
Trends
The purpose of this chapter is to address the first leg of the three-legged
stool approach for answering the question posed in Chapter 1—Has the Clean
Water Act's regulation of waste-water treatment processes at POTWs been a
success? Recall that the basic goal of this first leg is to examine the extent to
which the Nation's investment in building and upgrading POTWs to secondary
and greater than secondary wastewater treatment resulted in a decrease in
effluent BOD loading to the Nation's waterways. If evidence showed that these
investments achieved significant reductions in the discharge of oxygen-demanding
organic wasteload to the Nation's waterways, the first leg of the investigation
could add cumulative support for the conclusion that the CWA's mandates were
successful.
This section summarizes the key points presented in Sections A through F
of Chapter 2, discusses conclusions, and addresses future trends in wastewater
infrastructure requirements.
Key Points of the Background Sections
Specifically discussed in Sections A and B is the significance of water
supply and wastewater treatment in the urban water cycle, the invention of
secondary treatment, and the use of biochemical oxygen demand (BOD) as a
measure of the pollutional strength of organic wasteloads. Section C focuses on
the roles the federal government and the CWA played in establishing, and funding,
secondary and greater than secondary treatment in the Nation's POTWs.
Key points made in Sections A through C include the following:
• All components of the urban water cycle must be in place and function-
ing properly to satisfy the needs of both water supply and water
resource users.
In the "Great Sanitary Awakening" in the late 19th and early 20th
centuries, public infrastructure investment was focused primarily on the
water supply side of the urban water cycle and sewage collection
systems for the control of waterborne diseases and protection of public
health.
• Increasing urban populations in the first half of the 20th century exac-
erbated water quality problems associated with the discharge of
inadequately treated sewage in urban waterways.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
Secondary treatment proved to be a breakthrough discovery in treating
wastewater; by 1930 several cities, especially in the Northeast, Mid-
west, and far West, had incorporated the technology into their waste-
water treatment systems.
Before 1972 and the passage of the CWA, municipal and industrial
wastewater discharges were regulated by individual states based on
state ambient water quality standards. The federal government's
authority for water pollution control was restricted to interstate water-
ways under the Commerce clause of the U.S. Constitution.
The passage of the CWA resulted in the federal government's assum-
ing a greater role in directing and defining water pollution control
programs in the Nation. The states' water quality-based approach for
regulating wastewater discharges was replaced by the CWA's two-
pronged approach—a mandatory technology-based approach supple-
mented by a water quality-based approach on an as-needed basis—and
enforced under the National Pollutant Discharge Elimination System
permit program.
Section 301 of the CWA required POTWs to achieve effluent
limitations based on secondary treatment as the minimum level of
technology.
Key Points of the BOD Loading Analysis Sections
Establishing a national policy requiring secondary treatment of municipal
wastewater as the minimum acceptable technology supplemented by more
stringent water quality-based effluent controls on a site-specific, as-needed basis
was a key provision of the 1972 CWA. This mandate, coupled with an increase in
funding assistance to municipalities through the Construction Grants Program, led
to a dramatic increase in the number of POTWs with secondary and greater than
secondary treatment capabilities.
Section D examines several national POTW trends, including the population
they serve, influent and effluent BOD loadings, and BOD removal efficiencies.
Key findings include the following:
• The U.S. population served by POTWs with secondary or greater
treatment almost doubled between 1968 and 1996 from 85.9
million people in 1968 to 164.8 million people in 1996!
• BOD loading to POTWs (influent loading) increased significantly.
In 1968 influent BODu loading was 34,693 metric tons per day. By
1996 influent BODu loading stood at 46,979 metric tons per day, a 35
percent increase from 1968! The same trend was seen for influent
BOD5 loading to POTWs.
• Effluent BOD loading discharged by POTWs was significantly
reduced. In 1968 effluent BODu loading was 21,281 metric tons per
day. By 1996 effluent BODu loading stood at 16,325 metric tons per
day, a 23 percent decrease from 1968! Effluent BOD5 loading was also
significantly reduced (by 45 percent) over the same time period.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
BOD removal efficiency increased significantly. In 1940 the aggre-
gate national removal efficiency stood at about 33 percent for BOD5
and 20 percent for BODu. By 1968 removal efficiencies had increased
to 63 percent for BOD5 and 39 percent for BODu. By 1996 these had
increased to nearly 85 percent for BOD5 and 65 percent for BODJ
• Increasing numbers of people served by POTWs in the 21st cen-
tury will likely reverse the trend established between 1968 and
1996 of decreasing effluent BOD loading to the Nation's water-
ways. Assuming that national aggregate design-based BODu removal
efficiency will increase to 71 percent, influent wastewater flow will
remain a constant 165 gpcd, and influent BODu concentrations will
remain a constant 396.5 mg/L, population projections indicate that by
2016 effluent BODu loading will increase by 20 percent to 19,606
metric tons per day, equivalent to the rate in the mid-1970s. It is
projected that by 2025 the effluent BODu loading will be 21,280 metric
tons per day, a rate approximately equal to that observed in 1968 when
the discharge of oxygen-demanding material from POTWs reached its
historical peak!
• By 2016, when the projected needs for wastewater treatment are
expected to be met (USEPA, 1997), the overall BODu removal
efficiency of 71 percent and increases in population will result in a
20 percent increase of effluent loads relative to the 1996 loading
rate. To maintain an effluent BODu loading rate comparable to 1996
conditions through 2016 (i.e., "running in place"), the national aggregate
removal efficiency would have to be increased from 71 to 76 percent.
This would need to be accomplished by shifting the projected population
served from secondary to advanced secondary and advanced waste-
water treatment facilities.
Section E presents a national "snapshot" comparison of contemporary (ca.
1995) BOD5 loadings from POTWs and other point and nonpoint sources based
on available data from PCS and the Clean Water Needs Survey. Using the
NWPCAM (Bondelid et al., 1999), BOD5 loadings were estimated for municipal
(POTW) and industrial point sources (major and minor), CSOs, and rural and
urban1 nonpoint sources. Loading data for each category were aggregated by
catalog units and major river basins. The inclusion of other loading sources in this
modeling exercise helps put the municipal loading component in perspective with
total nationwide BOD5 loading from all sources. Key findings include the follow-
ing:
• Of the 2,111 catalog units in the contiguous United States, 1,632
receive municipal discharges.
• Twenty percent of catalog units account for 90 percent of the total
municipal BOD5 loading. Highest rates of municipal loading of BOD5
occurred in the Mississippi River Valley and the Northeast and
Midwest.
1 For purposes of this comparison, urban stormwater runoff includes areas both outside (termed
"nonpoint sources") and within (meeting the legal definition of a point source in section 502(14)
of the CWA) the NPDES stormwater permit program.
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
• Municipalities (POTWs) are the dominant source of the BOD}
component in catalog units associated with major urban areas.
Several urban areas had rates greater than 25 metric tons per day.
• Municipal BOD; loadings account for about 38 percent of total
point source loadings and 21 percent of total loadings (point and
nonpoint).
• Industrial (major and minor) BOD5 loadings account for about 62
percent of total point source loadings and 34 percent of total
loadings (point and nonpoint).
• Urban stormwater and CSOs account for about 5 percent of total
nonpoint source loadings and 2 percent of total loadings (point
and nonpoint).
• Rural nonpoint source BOD} loadings account for about 95
percent of total nonpoint source loadings and 43 percent of total
loadings.
Clearly, continued improvement in water quality conditions of the Nation's
waterways will require an integrated strategy to address all pollutant sources,
including both point and nonpoint sources.
Key Points of the Investment Costs Section
Section F focuses on investment costs associated with water pollution
control. It includes a discussion of the Construction Grants Program and provides
summaries of program spending for new construction and upgrades of POTWs.
Also included in this section are summaries of public and private investment totals
in point source water pollution control. Key findings include the following:
• From 1970 to 1995 the Construction Grants Program has distrib-
uted $61.1 billion (as current year dollars) to municipalities for
POTW building and upgrades. The federal share was 75 percent of
total costs from fiscal years 1973 to 1983, and 55 percent thereafter.
From 1988 to 1999 an additional $16.1 billion (capitalization) in
federal contributions was also distributed to the states through the
Clean Water State Revolving Fund.
• From 1972 to 1994 approximately $200.6 billion in capital costs
and $210.1 billion in operation and maintenance costs (as current
year dollars) were spent by the public and private sectors for point
source water pollution control. Based on these figures, the Construc-
tion Grants Program has contributed almost one-half of the public
sector costs and about one-third of the total public and private sector
capital investment for point source water pollution control.
• Excluding combined sewer systems and urban stormwater controls,
EPA estimates $75.9 billion (1996 dollars) will be required to meet
traditional wastewater treatment plant (and sewer) needs through
the year 2016 (USEPA, 1997).
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Conclusion of
the first leg
of the stool
There was a dramatic
nationwide decrease in
fromPOTWs after the
1972 CWA despite a
population served!
Conclusions and Future Trends
Based on the results of the analyses presented in this chapter, the study
authors propose the following conclusion regarding the first leg of the three-
legged stool approach concerning the Nation's investment in building and upgrad-
ing POTWs to achieve at least secondary treatment: The CWA's mandated
POTW upgrades to at least secondary treatment, combined with financial
assistance from the Construction Grants Program and Clean Water State
Revolving Fund, resulted in a dramatic decrease in effluent BOD
loading from POTWs to the Nation's waterways. This decrease was
realized in spite of significant increases in influent BOD loading that oc-
curred due to increases in the population served by POTWs.
Based on needs data submitted by the states, EPA projects that by the
year 2016,18,303 POTWs in the United States will be serving a population
of 274.7 million (USEPA, 1997). Excluding combined sewer systems and
storm water controls, the Agency estimates that $75.9 billion (1996 dollars)
will be required to meet traditional wastewater treatment plant and sewer
needs at this projected level of service. Based on these projections, influent
BODu loading in 2016 is estimated to be about 68,030 metric tons per day, a
45 percent increase in influent BODu loading from 1996 (see Section D).
Assuming a BODu removal efficiency of 71 percent based on the effluent
loads contributed by different categories of POTWs (USEPA, 1997),
effluent BODu loading in 2016 would be about 19,606 metric tons per day.
The projected effluent BODu loading of 19,606 metric tons per day in
2016 is a concern. Directly and indirectly due to the implementation of the
CWA, there was a downward trend of effluent BODu loading rates begin-
ning in the early 1970s through at least 1996 (the endpoint year of this
study). The highest effluent BODu loading rate, 21,281 metric tons per day,
was estimated to have occurred in 1968, four years before the passage of
the CWA, and the lowest, 16,325 metric tons per day, in 1996. The 2016
effluent BODu loading estimate reverses the downward trend, with a 20
percent increase in effluent loading over the 20-year period from 1996 to 2016.
This level of loading is equivalent to the effluent BODu loading rates in the mid-
1970s. Further, effluent loading rates projected to 2025 reveal that the Nation may
experience loading rates similar to those occurring in 1968, a time when the
symptoms of water pollution were especially acute.
These findings underscore the importance of incorporating pollutant loading
estimates and corresponding water quality improvements into POTW needs
surveys. Projected large increases in service population have the potential to
overwhelm the gains made to date in effluent BOD loading reductions due to the
CWA. To continue the downward trend in effluent BOD loading to the Nation's
waterways, further improvements need to be made in technologies and actions
that decrease influent BOD loading to POTWs (through conservation methods)
and increase BOD removal efficiency in the Nation's POTWs (through more
advanced wastewater treatment methods).
In the 25 years since the passage of the CWA, a majority of the national
water pollution control efforts have focused on controlling pollutants from
POTWs and other point sources. National standards ensure that every discharger
meets or beats the performance of the best technology available. Continuing the
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
success achieved to date in reducing BOD and other pollutants, however, will
require additional investment as older facilities wear out and increasing population
pressures demand that existing facilities expand and new facilities be constructed.
If these investments are not made and treatment services do not keep pace with
growth, many of the gains achieved by the effluent loading reductions that have
occurred in the years after the CWA will be lost (WIN, 2000). If this occurs, the
wastewater treatment component of the urban water cycle will again assume
"weak link" status, with corresponding detrimental consequences to water
resource users.
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Tetra Tech. 1999. Improving point source loadings data for reporting na-
tional water quality indicators. Final Tech. Report. Prepared for U.S.
Environmental Protection Agency, Office of Wastewater Management,
Washington, DC, by Tetra Tech, Inc., Fairfax, VA.
Thomann, R.V. and J.A. Mueller .1987. Principles of surface water quality
modeling and control. Harper & Row, Inc., New York, NY.
USCB. 1975. Historical statistics of the United States: Colonial times to
1970. Series B 193-200. U.S. Census Bureau, Washington, DC.
USCB. 1996. Population projections of the United States by age, sex, race
and Hispanic origin: 1995-2050. Current Population Reports, Series p.25-
1130, Population Division, U.S. Census Bureau, Washington, DC.
USCB. 2000. Urban and rural population: 1900 to 1990. In: 1990 Census of
Population and Housing, "Population and Housing Unit Counts," CPH-2-1.
Population Division, U.S. Census Bureau, Washington, DC.
USEPA. 1972. 7972 NEEDS survey, conveyance and treatment of municipal
wastewater: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1973. Secondary treatment parameters. U.S. Environmental Protection
Agency. Fed. Re gist., April 30, 1973, 38:12973.
USEPA. 1974. National water quality inventory, 1974. EPA-440/9-74-001.
U.S. Environmental Protection Agency, Office of Water Planning and
Standards, Washington, DC.
USEPA. 1976. 1976 NEEDS survey, conveyance and treatment of municipal
wastewater: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1978. 1978 NEEDS survey, conveyance and treatment of municipal
wastewater: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1980. 1980 NEEDS survey, conveyance and treatment of municipal
wastewater: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1982. 1982 NEEDS survey, conveyance, treatment, and control of
municipal wastewater, combined sewer overflows and stormwater
runoff: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1984. 1984 NEEDS survey, conveyance, treatment, and control of
municipal wastewater, combined sewer overflows and stormwater
runoff: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1986. 1986 NEEDS survey, conveyance, treatment, and control of
municipal wastewater, combined sewer overflows and stormwater
runoff: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
2-76
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Chapter 2: An Examination of BOD Loadings Before and After the CWA
USEPA. 1989. 1988 NEEDS survey, conveyance, treatment, and control of
municipal wastewater, combined sewer overflows and stormwater
runoff: Summaries of technical data. U.S. Environmental Protection
Agency, Office of Water Program Operations, Washington, DC.
USEPA. 1993. 7992 Clean Water Needs Survey (CWNS), conveyance,
treatment, and control of municipal wastewater, combined sewer over-
flows and stormwater runoff: Summaries of technical data. EPA-832-R-
93-002. Office of Water Program Operations, U.S. Environmental Protection
Agency, Washington, DC.
USEPA. 1997. 1996 Clean Water Needs Survey (CWNS), conveyance,
treatment, and control of municipal wastewater, combined sewer over-
flows and stormwater runoff: Summaries of technical data. EPA-832-R-
97-003. Office of Water Program Operations, U.S. Environmental Protection
Agency, Washington, DC.
USPHS. 1951. Water pollution in the United States. A report on the polluted
conditions of our waters and what is needed to restore their quality.
U.S. Federal Security Agency, Public Health Service, Washington, DC.
Viessman, W., and MJ. Hammer. 1985. Water supply and pollution control.
4th ed. Harper & Row, New York, NY.
Vogan, C.R. 1996. Pollution abatement and control expenditures, 1972-94.
Survey of current business. Vol. 76, No. 9, pp. 48-67. U.S. Dept. of
Commerce, Bureau of Economic Analysis, Washington, DC.
WEE 1997. The clean water act. 25th Anniversary ed. Water Environment
Federation, Alexandria, VA.
WIN. 2000. Clean and safe water for the 21st century: A renewed national
commitment to water and wastewater infrastructure. Water Infrastructure
Network, Washington, DC.
Zwick, D., and M. Benstock. 1971. Ralph Nader's study group report on water
pollution: Water wasteland. Grossman Publishers and Bantam Books, New
York, NY.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
2-78
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Chapter 3
An Examination of "Worst-
Case" DO in Waterways
Below Point Sources
Before and After the CWA
Chapter 2 discussed the evolution of the BOD measurement, the impact
of BOD loadings on DO levels in natural waters, and the massive
amount of public and private money invested in municipal wastewater
treatment to meet the mandates of the CWA. Key conclusions from the first leg
of the three-legged stool approach are:
• The Nation's investment in building and upgrading POTWs significantly
reduced BOD effluent loading to the Nation's waterways.
• This reduction occurred in spite of a significant increase in influent
BOD loading caused by an increase in population served by POTWs.
The second leg follows up on the first leg with another question—Has the
CWA's push to reduce BOD loading resulted in improved water quality in the
Nation's waterways? And, if so, to what extent? The key phrase in the question
is "to what extent?" Earlier studies by Smith et al. (1987a, 1987b) and Knopman
and Smith (1993) conclude that any improvements in DO conditions in the
Nation's waterways are detectable only within relatively local spatial scales
downstream of wastewater discharges.
"Perhaps the most noteworthy finding from national-level monitor-
ing is that heavy investment in point-source pollution control has
produced no statistically discernible pattern of increases in
water's dissolved oxygen content during the last 15 years [1972-
87]. . . . The absence of a statistically discernible pattern of
increases suggests that the extent of improvement in dissolved
oxygen is limited to a small percentage of the nation's total stream
miles. This is notable because the major focus of pollution control
expenditures under the act [CWA] has been on more complete
removal of oxygen-demanding wastes from plant effluents"
— Knopman and Smith, 1993
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
The purpose of the second leg of this investigation is to examine evidence
that may show that the CWA's municipal wastewater treatment mandates ben-
efited water quality on a broad scale, as well as in reaches immediately down-
stream from POTW discharges. The systematic, peer-reviewed approach used in
this investigation includes the following steps:
Developing before- and after-CWA data sets composed of DO sum-
mary statistics derived from monitoring stations that were screened for
worst-case conditions. The purpose of the screening exercise is to mine
data that inherently contain a response "signal" linking point source
discharges with downstream water quality.
• Calculating a worst-case DO summary statistic for each station for
each before- and after-CWA time period and then aggregating station
data at sequentially larger spatial scales (reaches, catalog units, and
major river basins).
• Conducting an analysis of spatial units that have before- and after-
CWA worst-case DO summary statistics and then documenting the
direction (improvement or degradation) and magnitude of the changes
in worst-case DO concentration.
• Assessing how the point source discharge/downstream DO signal
changes over progressively larger spatial scales.
Section A of this chapter provides background on the relationship between
BOD loading and stream water quality and discusses the two key physical
conditions (high temperature and low flow) that create "worst-case" conditions
for DO. Section B describes the development and application of a set of screen-
ing rules to select, aggregate, and spatially assess before- and after-CWA DO
data drawn from USEPA's STORET database. Section C presents the results of
the comparison analysis of worst-case DO from before and after the CWA for
reach, catalog unit, and major river basin scales. The chapter concludes with
Section D, which provides the summary and conclusions for the second leg of
this investigation.
A. Background
In both terrestrial and aquatic ecosystems, the continuous cycle of produc-
tion and decomposition of organic matter is the principal process that determines
the balance of organic carbon, nutrients, carbon dioxide, and DO in the biosphere.
Plants (autotrophs) use solar energy, carbon dioxide, and inorganic nutrients to
produce new organic matter and, in the process, produce DO by photosynthesis.
Bacteria and animals (heterotrophs) use the organic matter as an energy source
(food) for respiration and decomposition, and in these processes, consume DO,
liberate carbon dioxide, and recycle organic matter back into the ecosystem as
simpler inorganic nutrients. Water quality problems, such as depleted levels of
DO, nutrient enrichment, and eutrophication (overproduction of aquatic plants),
occur when the aquatic cycle of production and decomposition of organic matter
becomes unbalanced from excessive amounts of anthropogenic inputs of organic
carbon and inorganic nutrients from wastewater discharges and land use-influ-
enced watershed runoff.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
DO is the most meaningful and direct signal relating municipal and industrial
discharges to downstream water quality responses over a wide range of temporal
and spatial scales. In addition to DO's significance as a measure of aquatic
ecosystem health, there are several other practical reasons for choosing DO as
the signal for assessing changes in water quality, including the following:
Historical records go as far back as the early 20th century for many
major waterbodies. New York City, for example, began monitoring DO
in New York Harbor in 1909 and records exist for the Upper Missis-
sippi River beginning in 1926, the Potomac estuary in 1938, and the
Willamette River in 1929 (see Wolman, 1971).
• Basic testing procedures for measuring DO have introduced few biases
over the past 90 years, thereby providing the analytical consistency
needed for comparing historical and modern data (Wolman, 1971).
This section provides background on sources of DO data, the relationship
between BOD loading, downstream DO levels, and the two key physical condi-
tions (high temperature and low flow) that create "worst-case" DO conditions.
As will be explained, DO data collected under worst-case conditions inherently
contain the sharpest signal of the point source discharge/downstream DO rela-
tionship.
Sources of DO Data
Key to this analysis is the existence of DO data with which a before- and
after-CWA comparison can be made. Fortunately, systematic water pollution
surveillance of many of the Nation's waterways began in 1957 in response to the
1956 Amendments to the Federal Water Pollution Control Act. Figure 3-1 is a
map developed by Gunnerson (1966) displaying minimum DO concentrations
throughout the United States using data collected from 1957 through 1965. It
illustrates both the spatial extent of historical data and the poor DO conditions
found in many of the Nation's waterways in the late 1950s and early 1960s.
O > 6.5 mg/L
® 4.1 to 6.5 mg/L
O 0.5 to 4.0 mg/L
• < 0.5 mg/L
Figure 3-1
Location of sample
stations and minimum DO
concentrations in the
contiguous 48 states from
1957 to 1965.
Source: Gunnerson, 1966.
3-3
-------
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i
-------
Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
"Worst-Case" Conditions as a Screening Tool
The first step in developing the before- and after-CWA data sets was to
analyze the relationship between point source BOD loading and downstream DO
levels. As the reader will see in Section B, the rules subsequently adopted and
applied to screen out noisy data were based on eliminating physical factors that
interfered with, or confounded, the point source discharge/downstream DO signal.
As it turned out, the DO data that contained the strongest signal were the data
collected under conditions that yielded the lowest DO levels (high water tempera-
ture and low flow). The purpose of this subsection is to explain the physical
processes and spatial characteristics that make worst-case conditions the appro-
priate screening tool for developing the before- and after-CWA data sets.
Worst-Case Conditions From a Temporal Perspective
In an unpolluted stream, DO concentrations in most of the water column are
typically at or near saturation. Saturation, however, varies inversely with water
temperature and elevation. At typical winter water temperatures of about 10 °C,
the solubility of oxygen is about 11.3 mg/L at sea level. At a higher summer
temperature of 25 °C, the solubility is only about 8.2 mg/L. This high water
temperature-low solubility relationship makes hot weather an especially critical
period for aquatic organism survival. Higher water temperatures mean a lower
reserve of oxygen is available to buffer against any additional oxygen demands
made by wastewater effluent discharges.
Wastewater effluent typically has an oxygen deficit (a DO concentration
below saturation). Therefore, its initial entry into a waterway causes an immedi-
ate drop in stream DO near the outfall. The effluent becomes diluted as it mixes
with the stream water and moves down the channel. The BOD of the stream
water thus becomes the discharge-weighted average BOD of the effluent and the
stream above the discharge. The volume of streamflow (the dilution factor),
therefore, is a critical variable in determining the concentration of oxygen-
demanding waste. Consequently, periods of low flow in the stream channel yield
the highest concentration of BOD.
The combination of unnaturally high levels of BOD inputs, high water
temperature, and low stream flow creates worst-case DO levels in streams and,
in turn, the most critical conditions for the survival of aquatic organisms; that is,
conditions of increased oxygen demand, low oxygen solubility, and low dilution
potential. Fortunately, worst-case conditions do not occur all the time. Although
the BOD loading component tends to remain relatively stable over the course of a
year, there are usually distinct seasonal variations in temperature and rainfall
(directly related to flow). On an annual basis in the contiguous United States, the
highest water temperatures and minimal flow levels usually occur from early
summer to late fall. Therefore, the months of July through September are gener-
ally considered "worst-case" months for DO.
Observations of year-to-year variations in climate reveal that many areas on
the earth, including the United States, experience runs of wet and dry years, a
phenomenon known as persistence. The short time frame of historical record-
keeping makes it difficult for scientists to predict exactly when these wet and dry
year cycles will occur; however, more than 100 years of rainfall data have proven
that they are not uncommon. Importantly, persistence tends to have a cumulative
3-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
effect on stream conditions. Therefore, the worst-case scenario for DO in
waterways from a temporal perspective can be further refined to include the
months of July through September (worst-case months) during a run of dry years
(worst-case persistence).
Defining the periods of years before and after the CWA to represent worst-
case persistence was accomplished in three steps. In the first step, USGS flow
data taken from approximately 5,000 gages with over 20 years of record during
the period from 1951 to 1980 were classified into "dry," "normal," and "wet"
years. Normalized ratios of summer (July to September) streamflow to long-term
summer mean were computed for each gage for each year. Years with ratios less
than 0.75 were considered dry; normal years had ratios from 0.75 to 1.5, and wet
years were defined as having ratios greater than 1.5.
Figure 3-3 illustrates how widely mean summer flow can vary over time.
The figure displays USGS gage data from the Upper Mississippi River at St. Paul,
Minnesota, for the years 1960 through 1995. The scale on the left Y axis is
streamflow measurements as thousands of cubic feet per second (cfs). The scale
on the right Y axis is the interannual-to-long-term mean (10,658 cfs) streamflow
ratio. Note that the benchmark ratio of 0.75 (which distinguishes dry from normal
years) is represented by the dashed horizontal line. This graph shows that dry
summers with low flow occurred in St. Paul in the years 1961, 1970, 1976, 1980,
and 1987-1989. The data from this gage also show the enormous wet conditions
that occurred primarily in response to the "Great Flood of 1993." That year the
mean summer flow was about 4.5 times greater than the normal mean summer
flow.
For the second step, a sliding window methodology was used as an algo-
rithm to weight and interpolate normalized streamflow ratios for multiple gages
within a catalog unit. The outcome was a weighted streamflow ratio assigned to
each catalog unit for each year from 1961 through 1995. Similar to the gage-scale
streamflow ratio, the catalog unit-scale streamflow ratio was used to classify
catalog units into dry (< 0.75), normal (0.75-1.5), and wet (> 1.5) years.
The third and final step used to define the periods of worst-case dry persis-
tence before and after the CWA involved grouping the 35-year period from 1961
to 1995 into consecutive 5-year "time-blocks." Then for each catalog unit, the
number of years within each time-block during which the catalog unit scale
streamflow ratio was below 0.75 (i.e., dry) was determined. Rather than using the
seemingly obvious 5-year time-block of 1966-1970 to characterize water quality
Figure 3-3
Time series of mean
summer (July-September
1960-1995) streamflow
and ratio of mterannual to
long-term (1951-1980)
summer mean.
(Data from USGS Gage
05331000 on the Upper
Mississippi River near
Minneapolis-St. Paul,
Minnesota)
0.00
1960 1965 1970 1975 1980 1985 1990 1995
3-6
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
conditions "before" the 1972 CWA, 1961-1965 was selected instead to represent
conditions "before" the CWA while 1986-1990 was used to characterize condi-
tions "after" the CWA.
Widespread drought conditions, a critical factor for "worst-case" water
quality conditions, occurred in the Northeast, Middle Atlantic, Midwest, and
Central states during both of these "before and after" 5-year time-blocks of
record (i.e., 1961-1966 and 1987-1988). The widespread extent of drought
conditions during the "before and after" time-blocks is shown in Figure 3-4 with
maps of normalized streamflow ratios computed for each catalog unit for 1963
and 1988.
For the 5-year time-block of 1961-1965, selected to represent before-CWA
conditions, 1,923 (91 percent) of the 2,111 catalog units of the 48 contiguous states
were characterized by at least one year of "dry" streamflow conditions. Similarly
for the 5-year time-block of 1986-1990 "after" the CWA, 1,776 (84 percent) of
the 2,111 catalog units of the 48 contiguous states were characterized by at least
one year of "dry" streamflow conditions. For the catalog units characterized as
"dry," low flow conditions occurred for a mean period of 2.5 years during 1961-
1965 and 2.7 years during 1986-1990 (Figure 3-5). Hydrologic conditions for the
summers of 1963 and 1988 are shown to illustrate the similarity of the spatial
extent of drought conditions within the 48 contiguous states during the before- and
after-CWA time-blocks. Using this station selection approach based on summer
streamflow ratios, trends identified for "before versus after" changes in DO can
then be correctly attributed to changes in pollutant loadings (under comparable
"dry" streamflow conditions) rather than to differences in hydrologic conditions.
Worst-Case Conditions from a Spatial Perspective
In a clean river, upstream of any wastewater inputs, DO levels are typically
near saturation. Downstream of an effluent discharge, however, measurements of
DO lower than saturation exhibit a characteristic spatial pattern influenced by the
loss of oxygen from degradation of organic matter and nitrification and the
replenishment of oxygen transferred from the atmosphere into the river (see
Thomann and Mueller, 1987; Chapra, 1997). An understanding of the spatial
pattern of DO in rivers was critical for the design of the screening methodology
used to detect "worst-case" conditions from a spatial perspective. Using river
miles from a downstream confluence as a measure of distance along the river,
Figure 3-6 illustrates spatial patterns of carbon (CBOD), nitrogen (organic-N,
NH3-N, and NO2-N + NO3-N), and DO in zones identified as "clean," "degrada-
tion," "active decomposition," and "recovery" that are upstream and downstream
of a POTW discharge.
In streams and rivers, DO levels are maintained near saturation by the
continuous transfer of atmospheric oxygen into solution in a thin surface layer of
the river. The rate of transfer of atmospheric oxygen into the river (i.e., mixing of
oxygen as a gas from the air into solution in the water) depends on how fast the
river is running, how deep the water is, how "bubbly" the river appears to be, the
water temperature, and how much oxygen is already in solution in the river. The
less oxygen that is in solution in the river, the faster more oxygen can be trans-
ferred from the air into the water. In the "degradation" zone, more oxygen is
being consumed by decomposition than can be replenished from the atmospheric
supply of oxygen and DO levels quickly drop. In the "active decomposition" zone,
3-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-4
Hydrologic conditions during July-September of (a) 1963 and (b) 1988.
Summer streamflow ratio estimated for each
catalog unit as a percentage of long-term mean
summer streamflow (July-September, 1951-1980).
Hydrologic conditions characterized as dry (0%-75%)
normal (75%-150%), and wet (greater than 150%)
Streamflow Ratio
Less than 50
SO-75
75-100
100-150
150-200
Greater than 200
Data Not Availabe
3-8
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Chapter 3: An Examination of "Worst-Case" DO In Waterways Below Point Sources Before and After the CWA
Figure 3-5
"Dry" hydrologic conditions during July- September of (a) 1961-1965 and (b) 1986-1990.
"Dry" Streanticw
O Years "Dry1'
I I 1-2 Years'Dry"
CD 3-5 Years "Dry"
Summer streamflow ratio estimated for each
catalog unit as a percentage of long-term mean
summer streamflow (July-September, 1951-1980).
Hydrologic conditions characterized as dry (0%-75%)
normal (75%-150%), and wet (greater than 150%).
3-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-6
Spatial distribution of
(a) organic carbon
(CBOD), (b) nitrogen
(organic nitrogen,
ammonia, nitrite, and
nitrate), and (c) DO
downstream of a waste-
water discharge into a
river.
Source: Adapted from
Chapra, 1997 and
Thomann and Mueller,
1987.
Wastewater discharge
(a)
Clean water
-60
Degra- Active
dation decomposition
Recovery
-50
-40 -30 -20 -10
Distance From Confluence (miles)
-50 -40 -30 -20 -10
Distance From Confluence (miles)
(b)
-50 -40 -30 -20 -10
Distance From Confluence (miles)
(C)
10
O)
6-
•a 4
0)
<« 2
5
Oxygen saturation (7.8 mg/L)
Oxygen standard (5 0 mg/L)
t
Critical location
-60 -50 -40 -30 -20 -10
Distance From Confluence (miles)
3-10
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
more oxygen is gained by the mixing of oxygen from the air into the water than is
lost by the continued decomposition of a diminishing amount of carbon (CBOD)
and nitrogen (NBOD) and oxygen gradually increases. In the "recovery" zone,
the rate of atmospheric replenishment of oxygen greatly exceeds the oxygen lost
due to small levels of CBOD and NBOD remaining in the river and oxygen
returns to the saturation level.
Immediately downstream from the POTW, the carbon concentration
(CBOD) jumps from the low upstream level to a much higher flow-weighted
CBOD concentration as the effluent load is diluted with the ambient upstream
load (Figure 3-6(a)). Bacterial decomposition of the carbon results in a steady
decrease of in-stream CBOD and a steep drop in oxygen in the "degradation"
zone followed by a continued decline of CBOD with a gradual increase in oxygen
in the "active decomposition" zone.
As shown in Figure 3-6(b) for the spatial patterns of nitrogen, organic
nitrogen (Organic-N) and ammonia nitrogen (NH3-N) both jump from a low
upstream level following mixing of the wastewater load with the ambient up-
stream load. As organic nitrogen declines by hydrolysis, the nitrification process
begins (if a sufficient "seed" population of nitrifying bacteria is present), ammonia
is oxidized to nitrite, and nitrite is quickly oxidized to nitrate. In the figure, nitrite
and nitrate are shown combined as the sum (NO2-N + NO3-N) of these two
inorganic forms of the nitrogen cycle. As the sequential reactions of the nitrogen
cycle proceed downstream, the concentration of total nitrogen (Total-N) remains
unchanged to maintain the mass balance of the reactions between the organic and
inorganic forms of nitrogen. In these sequential oxidation reactions of nitrification,
the nitrogenous oxygen demand (NBOD) consumes oxygen faster than it can be
replenished by atmospheric reaeration and oxygen drops.
The combined effect of the decomposition of carbon and nitrogen causes a
characteristic critical low DO zone identified by a "sag" in the spatial distribution
of oxygen (Figure 3-6(c)). Two key features of the "oxygen sag" curve are
especially important for the purposes of this study:
• The magnitude of the minimum DO concentration.
• The distance downstream from a waste discharge affected by "degra-
dation" and "active decomposition."
In designing the screening methodology to detect the "worst case" for
oxygen from a spatial perspective, it is important to recognize that water quality
monitoring stations located immediately downstream of wastewater inputs will
most likely be within the zones of "degradation" or "active decomposition" but not
necessarily at the minimum, or critical, location of the sag. For monitoring stations
located considerably farther downstream from a wastewater discharge location, it
is less likely that the station will be within the "degradation" or "active decomposi-
tion" zones of the river. It is more likely, rather, that the station(s) will be located
in the "recovery" zone. For any stream or river, the actual locations that mark the
beginning and end of these zones are highly variable. The spatial pattern of
oxygen shown in Figure 3-6(c) is dependent on a number of factors, including
streamflow and river velocity (travel time), depth, water temperature, the type
and makeup of effluent discharged, the magnitude of the wastewater discharge
load, and the degree of turbulent mixing. Rather than attempting to select stations
that are located in the exact sag zone, which would undoubtedly show the sharp-
est downstream DO signal but in the smallest area of the waterbody, the opposite
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
approach was taken. That is, location of the station relative to the sag zone is
purposely not controlled or selected, thereby allowing representation of far larger
spatial areas but at the possible sacrifice of the downstream DO signal strength.
The question originally posed in Chapter 1 is broad-based: How have the
Nation's water quality conditions changed since implementation of the 1972
CWA 's mandate for secondary treatment as the minimum acceptable technol-
ogy for POTWs? The focus of the analysis is on detecting improvements in
water quality conditions downstream of POTWs in the Nation as a whole, not just
areas immediately below outfalls. Consequently, when the term "worst-case DO
data" is used in this document, it should be taken to refer to data collected
primarily during times of high water temperature and low flow conditions (i.e.,
"worst-case" from a temporal perspective). Spatially, no screens were developed
for selecting monitoring stations located at the deepest part of the sag curve, nor
even for stations in the sag curve itself. The only screening rule applied was that
the water quality station had to be downstream from a point source. Thus, a
station might be anywhere from within a few yards to hundreds of miles below
any particular outfall. As a result, the data sets developed for the comparative
before- and after-CWA analysis contain a mix of DO data from within and
outside DO sag curves.
The Role of Spatial Scale in This Analysis
Recall that the objectives for this portion of the study are as follows:
• Develop before- and after-CWA data sets made up of DO summary
statistics derived from monitoring stations that inherently contain a
response "signal" linking point source discharges with downstream
water quality.
• Calculate a DO summary statistic (10th percentile) for each station for
each before- and after-CWA time period and then aggregate station
data at sequentially larger spatial scales (reaches, catalog units, and
major river basins).
• Conduct an analysis of all spatial units having both a before- and an
after-CWA summary statistic and then document the direction and
magnitude of the changes in worst-case (summer, mean 1 Oth percen-
tile) DO concentration.
• Assess the change in the point source discharge/downstream DO
signal over progressively larger spatial scales.
The use of spatial scale is a key attribute of this analysis. Detection of
positive change in signal at large (river basin) as well as small (stream reach)
scales would provide evidence that the CWA's technology and water quality-
based controls yielded broad as well as localized benefits (i.e., reaches both within
and beyond the immediate sag curve have benefited from the CWA). If true,
therefore, the second leg of the three-legged stool approach would provide further
support for the claim that the CWA was a broad success.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
B. Data Mining
As discussed in the previous section, the key objective in the data mining
process was to screen out data collected under conditions or factors that might
interfere with, or confound, the point source discharge/downstream DO signal.
This section presents the six-step, peer-reviewed data mining process the study
authors developed and implemented to develop the before- and after-CWA data
sets to be used in the comparison analysis.
Step 1—Data Selection Rules
The data selection step incorporated three screening rules:
• DO, expressed as a concentration (mg/L), will function as the signal
relating municipal and industrial discharges to downstream water
quality responses.
• DO data will be extracted only from the July-September (summer
season) time period.
• Only surface DO data (DO data collected within 2 meters of the water
surface) will be used.
DO Concentration (mg/L) as the Water Quality Indicator
The rationale for selecting DO as the water quality indicator for this study
was discussed earlier in this chapter and in Chapter 2. The only question remain-
ing was how this parameter should be expressed in the analysis—by concentra-
tion or by percent of DO saturation. The latter measurement has some advan-
tages because it would reduce the noise introduced by changes in temperature.
However, DO expressed as mg/L concentration was ultimately selected because
it is more intuitive to a broader audience. For example, USEPA has established a
DO concentration of 5.0 mg/L as the minimum concentration to be achieved at all
times for early life stages of warm-water biota (see Table 1-1). For this reason,
this level of DO is used as a benchmark for assessing acceptable versus
nonacceptable conditions. In contrast, it is somewhat more difficult to compre-
hend whether a DO saturation of 50, 60, or 70 percent is protective.
DO From the Time Period of July to September
Summer and early fall (July through September) is usually the best time for
evaluating worst-case impacts of wastewater loading on water quality in general
and DO in particular. Typically, this is when water temperatures are highest and
flow is the lowest (i.e., lowest oxygen solubility and lowest dilution potential).
Selecting DO data from only this time period screens out noise introduced by
seasonal variations in temperature, precipitation, and flow. In addition, BOD
loadings from nonpoint sources of pollution are reduced during low precipitation
periods thus minimizing this contribution to DO signals.
DO from Surface Waters
In lakes, reservoirs, estuaries, coastal waters, and deep rivers, scientists
typically measure DO at several depths in the water column. Often these mea-
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
surements reveal significant differences between surface and bottom DO con-
centrations because of thermal stratification and the lack of reaeration of the
bottom layer. By limiting DO data selection to the top 2 meters of a waterway,
one can screen out much of the noise associated with the physical, chemical, and
biological processes that occur in the lower layers and maintain some level of
comparability between shallow streams and deeper waters.
Step 2—Data Aggregation Rules From a Temporal
Perspective
The data aggregation from a temporal perspective step incorporated the
following rules:
1961-1965 will serve as the time-block to represent persistent dry
weather before the CWA and 1986-1990 will serve as the time-block to
represent persistent dry weather after the CWA.
• To remain eligible for the before- and after-CWA comparison, DO data
must come from a station residing in a catalog unit that had at least 1
year classified as dry (streamflow ratio < 0.75) out of the 5 years in
each before- and after CWA time-block.
An analysis of catalog units revealed that 1,923 (91 percent) of the 2,111
catalog units in the contiguous United States experienced at least one dry summer
in the 1961-1965 time-block. Further, a total of 1,475 catalog units (70 percent)
experienced at least two dry summers and 886 catalog units (42 percent) experi-
enced at least three dry summers in the before-CWA time-block. Of the catalog
units that remained eligible for the comparison analysis (note that only 188 were
screened out), low flow conditions remained for an average of 2.5 years. In the
1986-1990 time-block, 1,776 (84 percent) of the 2,111 catalog units in the contigu-
ous United States experienced at least one dry summer. A total of 1,420 catalog
units (64 percent) experienced at least two dry summers and 1,073 catalog units
(51 percent) experienced at least three dry summers in the after-CWA time-
block. Of the catalog units that remained eligible for the comparison analysis (335
were screened out), low flow conditions remained for an average of 2.7 years.
Step 3—Calculation of the Worst-Case DO
Summary Statistic Rules
The calculation of the worst-case DO summary statistic step incorporated
the following rules:
• For each water quality station, the 1 Oth percentile of the DO data
distribution from the before-CWA time-block (July through September,
1961-1965) and the 10th percentile of the DO data distribution from the
after-CWA time-block (July through September, 1986-1990) will be
used as the DO worst-case statistic for the comparison analysis.
• To remain eligible for the before- and after-CWA comparison, a station
must have a minimum of eight DO measurements within each of the 5-
year time-blocks.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Typically, the mean or median statistic is used to summarize a distribution of
data because it describes the central tendency of the distribution. In this study,
however, the emphasis is on worst-case (low) DO. Consequently, a summary
statistic describing the lowest DO measurements of the data distribution was
needed because these data would inherently carry a sharper point source dis-
charge/downstream water quality signal. In other words, the objective was to
characterize the worst of the DO data collected under the worst-case physical
conditions (high temperature and low flow).
Because simply choosing the minimum measurement might introduce
anomalous results, the 10th percentile, a more robust statistic (i.e., one that
conveys information under a variety of conditions and is not overly influenced by
data values at the extremes of the data distribution) was selected as the appropri-
ate summary statistic to characterize the worst DO of a station's range of DO
measurements within a time-block. An example of how one might interpret a 10th
percentile value for a station is to say that 90 percent of the values collected at
that station were higher than the 10th percentile value. To minimize statistical
errors associated with calculating extreme percentiles, the requirement was added
that a station must have a minimum of eight observations within the 5-year time-
block to remain eligible for the before- and after-CWA comparison.
Step 4—Spatial Assessment Rules
The spatial assessment step incorporated one screening rule:
• Only water quality stations on portions of streams and rivers affected
by point sources will be included in the before- and after-CWA com-
parison analysis.
The objective was to develop before- and after-CWA data sets that contain
data that inherently contain a response signal linking point source discharges with
downstream water quality. Consequently, a screening rule reflecting the need to
ensure that DO data came from stations located downstream, rather than up-
stream, from point sources was required. As noted in Section A of this chapter,
the distance downstream was not relevant for the screening rule; the only require-
ment was that the station was somewhere in the downstream network.
Although the focus of this study is on effluent loading from POTWs,
changes in DO are tied to industrial discharges as well. Estimates of current (ca.
1995) BOD5 loading using the NWPCAM indicate that industrial loads are the
dominant component of total point and nonpoint source loading in many catalog
units associated with major urban-industrial areas (see Section E in Chapter 2).
For this reason, and because of the fact that it is not always possible to satisfacto-
rily distinguish between industrial and POTW outfalls because of their close
proximity in many areas, this leg of the study defines "point source discharges" to
include both industrial and municipal dischargers.
The upstream/downstream relationship between point source discharges and
water quality monitoring stations was established using USEPA's Reach File,
version 1 (RF1). RF1 is a computerized network of 64,902 river reaches in the 48
contiguous states, covering 632,552 miles of streams (see Figure 1-2). Using this
system, one can traverse stream networks and establish relative positions along
the river basin network of both free-flowing and tidally-influenced rivers.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-7
Reach File version 1 stream reach network of the 48 contiguous states with point source inputs discharging to a reach.
A list of point source dischargers was developed from EPA's Permit Com-
pliance System (PCS), Clean Water Needs Survey (CWNS), and Industrial
Facilities Discharge File (IFD). Spatially integrating the dischargers with RF1
resulted in identifying 12,476 reaches that are downstream of point source
dischargers (Figure 3-7) (Bondelid et al., 1999). These reaches, in turn, reside in
1,666 out of a total of 2,111 catalog units in the contiguous United States.
Example Application of the Screening Rules on DO Data From
a Single Water Quality Monitoring Station
Figure 3-8 illustrates how the above screening rules were applied to monitor-
ing station data to obtain worst-case DO data for the before- and after-CWA
comparison analysis. A station located on the Upper Mississippi River at Lock
and Dam No. 2 at Hastings, Minnesota, is used in this example. Figure 3-8(a)
displays a time series of the entire historical record (225 observations) of raw
ambient DO measurements for the station from 1957 to 1997. Note that DO
concentrations fluctuate from close to zero to slightly over 15 mg/L. The apparent
noise (rapid up and down movement of the DO line) is due to many factors,
including seasonal streamflow-water temperature and the time scale of the
graphic. Long-term interannual changes, on the other hand, might be due to
persistent dry or wet weather or changes in pollutant loading from the St. Paul
METRO wastewater facility.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
(a)
Figure 3-8
Application of the screen-
ing rules for station 21
MINN MSU-815-BB15E58
located in the Upper
Mississippi River: (a) time
series of historical DO
observations from 1957-
1997, (b) before- and after-
CWA frequency
distribution, and (c) 10th
percentile values.
Source: USEPASTORET
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
STORET7TYPA/AMBNT7STREAM
(b)
Before (1961-1985)
After (1986-1990)
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Percentile
(c)
Before
After
4.2
Mean 10%ile Dissolved Oxygen (mg/L)
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
In the data selection step, the study authors extracted from the raw data set
surface measurements collected at the station during the summer season (52
observations). Then, in the data aggregation step, they grouped the data in 5-year
time-blocks and focused in on the data from the before- and after-CWA persis-
tent dry weather time-blocks of 1961-1965 (10 observations) and 1986-1990 (15
observations). Because (1) the catalog unit in which the station resides had at
least one dry year in each of the before- and after-CWA time-blocks (streamflow
ratios: 1961 [0.31]; 1964 [0.65]; 1987 [0.59]; 1988 [0.22]; and 1989 [0.40]) and
(2) the number of observations for each grouping was confirmed to be greater
than eight, the groupings remained eligible for the next phase.
Distributions were made for each group and the 10th percentile determined.
Figure 3-8(b) displays the before- and after-CWA DO frequency distribution.
Figure 3-8(c) is a bar chart comparing the 10th percentile DO values of the
before- and after-CWA time-blocks. Note that the 10th percentile statistic
associated with the before-CWA period is below the USEPA's minimum concen-
tration of 5 mg/L, the level the Agency requires to be achieved at all times for
early life stages of warm-water biota.
Finally, the spatial assessment phase confirmed that the monitoring station
where the DO data were collected was on the Upper Mississippi River down-
stream of the St. Paul METRO water pollution control plant. Therefore, the
station remained eligible for the comparison analysis.
Step 5—Data Aggregation Rules From a Spatial
Perspective
The data mining steps described above were used to develop before- and
after-CWA sets of monitoring station data. Recall that
• The before- and after-CWA data sets are collections of DO summary
statistics that characterize worst-case DO at individual water quality
monitoring stations across the United States for the 1961-1965 and
1986-1990 time-blocks, respectively (one DO summary statistic per
station per time-block).
• The summary statistic used to characterize worst-case DO at a station
is the 10th percentile value of a data distribution of actual DO measure-
ments taken at the station during the specified time-block and recorded
in STORET. For the station to be eligible for inclusion in the data set, at
least eight measurements had to have been taken during the 5-year
time-block.
The purpose of the data aggregation from a spatial perspective step was to
assign a worst-case DO summary statistic to every eligible spatial unit defined at
the reach and hydrologic unit scales for the before- and after-CWA time-blocks.
This task was accomplished in two steps. First, for each data set and time-block,
the mean 10th percentile value from each eligible station was computed within the
spatial unit. (Since the scales are hierarchical, a station's summary statistic was
effectively assigned to a reach and a catalog unit.) Second, the mean 10th
percentile summary statistic was calculated and assigned to the spatial unit for the
purpose of characterizing its worst-case DO. If a spatial unit had only one
monitoring station within its borders meeting the screening criteria, the 10th
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
percentile DO value from that station simply served as the unit's worst-case
summary statistic. If, however, there were two or more stations within a spatial
unit's borders, the 10th percentile values for all the eligible stations were aver-
aged, and this mean value used to characterize worst-case DO for the unit. This
averaging process reduced the correlation between stations that were located
near each other. (Increased correlation reduces the effective sample size and
complicates statistical comparisons. Averaging across larger spatial scales tends
to reduce the correlation the most. As demonstrated later in this section, the
results from the different spatial scales are generally consistent and the impact of
spatial correlation is believed to be minimal.)
Step 6—Development of the Paired Data Sets (at
each spatial scale)
The purpose of the sixth and final step was to prepare the before- and after-
CWA data sets for the comparison analysis to be conducted at each of the three
sequentially larger hydrologic scales (RF1 reach, catalog unit, and major river
basin). The screening rule associated with this step was as follows
• To be eligible for the paired (i.e., before vs. after) comparison analysis,
a hydrologic unit must have both a before-CWA and an after-CWA
summary statistic assigned to it.
After each eligible reach and catalog unit was assigned a worst-case DO
summary statistic for the appropriate before- and after-CWA time-blocks, a
check was made to see which spatial units had both a before- and an after-CWA
summary statistic. For many reaches and catalog units, factors such as the
absence of dry flow conditions, station removal or changes in station location, or
water quality sampling over time (see Figure 3-2) caused a summary statistic to
be available for one time-block but not the other. In this case, the spatial unit was
removed from the analysis.
Implementation of this final step of the data mining process yielded the
following results:
• Of the 12,476 reaches identified as being downstream from point
sources, 311 reaches had both before- and after-CWA worst-case DO
summary statistics.
• Of the 1,666 catalog units identified as being impacted by point sources,
246 units had both before- and after-CWA worst-case DO summary
statistics.
• The 311 reach-aggregated DO summary statistics were pooled by the
18 major river basins in the contiguous United States. Using the statisti-
cal requirements to conduct a paired Mest as a criterion, 11 of the 18
major river basins had sufficient reach-aggregated worst-case DO data
to conduct the comparison analysis at the river basin level.
• The number of reaches and catalog units with both before- and after-
CWA DO data was constrained by the limited availability of station
records for the 1961-1965 before-CWA period (see Figure 3-2).
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
C. Comparison of Worst-Case DO in
Waterways Below Point Source
Discharges Before and After the
CWA at Three Spatial Scales
This section presents the comparative before- and after-CWA analysis of
worst-case DO data derived using the screening criteria described in Section B
and then aggregated by spatial units defined by three scales (reach, catalog unit,
and major river basin). In the discussion that follows, the term "worst-case DO"
should be interpreted to mean the average 10th percentile DO statistic computed
for the corresponding spatial level unless specifically noted otherwise. Also, the
reader should note that a worst-case DO concentration of 5 mg/L has been
adopted in this report as a general benchmark threshold for defining "desirable"
versus "undesirable" levels of worst-case DO. This benchmark value was chosen
primarily because USEPA has established it as the minimum concentration to be
achieved at all times for early life stages of warmwater biota (see Table 1-1).
Reach Scale
A total of 311 river reaches had monitoring stations with both before- and
after-CWA data and thus were eligible for comparison. Notably, these 311
evaluated reaches represent a disproportionately high amount of urban/industrial
population centers, with approximately 13.7 million people represented (7.2
percent of the total population served by POTWs in 1996). Of this total, 215
reaches (69 percent) showed improvements in worst-case DO after the CWA.
Figure 3-9 presents a frequency distribution of the before- and after-CWA data.
Figure 3-9
Frequency distribution
comparing worst-case DO
concentration of evaluated
reaches before and after
the CWA.
Source: USEPA STORET
30
I
£
CO
0
0)
25 -
20
(n) = number of RF1 reaches
• 1961-1965 (Before CWA)
W\ 1986-1990 (After CWA)
« 15
n
Q.
x—
O
0)
O)
(B
+j
V
£
0)
Q.
< Desirable levels
Undesirable levels >
Worst-Case DO (mg/L)
3-20
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Key observations from Figure 3-9 include the following:
The percentage of evaluated RF1 reaches characterized by "very low"
worst-case DO (< 2 mg/L) was reduced from 15 to 4 percent. Before
the CWA, 48 reaches had very low worst-case DO. After the CWA,
only 13 reaches had very low worst-case DO.
• The percentage of evaluated reaches characterized by undesirable
worst-case DO (below the 5 mg/L threshold) was reduced from 54 to
31 percent. Before the CWA, 167 reaches had undesirable levels of
worst-case DO. After the CWA, 97 reaches had undesirable levels of
worst-case DO.
• The percentage of evaluated reaches characterized by desirable worst-
case DO (above the 5 mg/L threshold) increased from 46 to 69 per-
cent. Before the CWA, 144 reaches had desirable levels of worst-case
DO. After the CWA, 214 reaches had desirable levels of worst-case
DO.
By tracking individual reaches, it was revealed that 85 of the 167 reaches
characterized by undesirable worst-case DO before the CWA improved to
greater than 5 mg/L after the act. On the flip side, only 15 of the 144 reaches
characterized by desirable worst-case DO before the CWA dropped below the 5
mg/L benchmark after the act. Thus, the net change was 70 reaches moving from
undesirable levels of worst-case DO to desirable levels of worst-case DO.
Figure 3-10 is a column graph that breaks down the 85 reaches that had
undesirable DO levels before the CWA and then improved past the benchmark
threshold of 5 mg/L after the act according to their before-CWA worst-case DO
concentration.
(n) = number of RF1 reaches
0 to 1 1 to 2 2 to 3 3 to 4 4 to 5
Worst-Case DO Before the CWA (mg/L)
Figure 3-10
Frequency distribution of
worst-case DO levels
before the CWA for the 85
evaluated reaches that
were < 5 mg/L before the
CWA and > 5 mg/L after
the CWA.
Source: USEPA STORET
3-21
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Key observations from Figure 3-10 include the following:
• Approximately 48 percent of the evaluated reaches (41 out of 85) that
had undesirable worst-case DO levels before the CWA and then
improved past the benchmark threshold of 5 mg/L after the act had
before-CWA worst-case DO in the 4-5 mg/L range.
Approximately 16 percent of the evaluated reaches (14 out of 85) that
had undesirable worst-case DO levels before the CWA and then
improved past the benchmark threshold of 5 mg/L after the act had
very low worst-case DO (< 2 mg/L) before the CWA.
Of the 311 evaluated reaches with paired before- and after-CWA data, 215
reaches (69 percent) had increased worst-case DO and 96 (31 percent) had
decreased worst-case DO after the CWA. Parts (a) and (b) of Figure 3-11
display the magnitude of degradation and improvement, respectively. Key obser-
vations from Figure 3-11 include the following:
• Approximately 36 percent of the evaluated reaches that had increases
in worst-case DO (78 of the 215 improving reaches) increased by 2
mg/L or more.
• Approximately 15 percent of the evaluated reaches that had decreases
in worst-case DO (14 of 96 degrading reaches) decreased by 2 mg/L
or more.
• Approximately 41 percent of all evaluated reaches either stayed the
same or improved or degraded by 1 mg/L or less (129 of the 311
reaches).
Figure 3-11
Frequency distribution of worst-case DO for evaluated RF1 reaches that (a) decreased in concentration (n = 96)
and (b) increased in concentration (n = 215) after the CWA. Source: USEPA STORET
(A
0)
£
U
re
0)
ft
•a
"5
0>
0)
o
0)
0.
(n) = number of RF1 reaches
7to8 6to7 5to6 4to5 3to4 2to3 1to2 Oto1
(a)
Magnitude of Decrease in
Worst-Case DO after the CWA
Oto1 1to2 2to3 3to4 4to5 5to6 6to7 7to8
(b)
Magnitude of Increase in
Worst-Case DO after the CWA
3-22
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Reaches with Greatest Improvements
Table 3-1 lists the 25 river reaches with the greatest before- and after-CWA
improvements in worst-case DO. Figure 3-12 presents a location map of these
reaches along with a stacked column graph that shows their before- and after-
CWA worst-case DO data. Key observations from Table 3-1 and Figure 3-12
include the following:
All but one of the top 25 river reaches with the greatest before- and
after-CWA improvements had before-CWA worst-case DO levels
below the benchmark threshold of 5 mg/L. Five reaches had a before-
CWA worst-case DO concentration of 0 mg/L.
For 20 of the 24 reaches with before-CWA worst-case DO levels
below the threshold value of 5 mg/L, after-CWA worst-case DO
improved to levels greater than 5 mg/L.
• The four reaches that did not break the threshold value of 5 mg/L
after the CWA all had a before-CWA worst-case DO concentration
of 0 mg/L.
• Worst-case DO in the top 10 improving river reaches typically im-
proved by about 4 to 7 mg/L (from about 0-3 mg/L in the 1961-1965
time-block to about 6-8 mg/L in the 1986-1990 time-block).
Table 3-1 . Twenty-five RF1 river reaches with greatest improvements in worst-case (mean 1 0th percen-
tile) DO after the CWA. Source: USEPA STORET
Worst- Worst- No. of
Rank
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
Reach ID
10170203037
04100002001
04110002001
05030103007
07070002034
05120201004
05080002008
07120004018
07090001004
05020006031
04040002005
02040201011
04030101012
03170006007
06010102004
08030203006
04040003001
04030104002
08030205018
05050008006
04120102002
03050109053
07120004002
05120201013
03050103037
River Reach
Name
Big Sioux R.
River Raisin
Cuyahoga R.
Mahoning R.
Wisconsin R.
White R.
Great Miami R.
Du Page R., E Br.
Rock R.
Casselman R.
Root R.
Neshaminy R.
Manitowoc R.
Pascagoula R.
Holston R, S Fk.
Enid L.
Milwaukee R.
Oconto R.
Grenada L.
Kanawha R.
Cattaraugus Cr.
Reedy R.
Des Plains R.
White R.
Catawba R.
Catalog Unit
Name
Lower Big Sioux, IA
Raisin, MI-OH
Cuyahoga, OH
Mahoning, OH-PA
Lake Dubay, Wl
Upper White, IN
Lower Great Miami, IN
Des Plaines, IL
Upper Rock, IL
Youghiogheny, MD
Pike-Root, IL
Crosswicks-Neshammy
Manitowoc-Sheboygan, Wl
Pascagoula, MS
South Fork Holston,
Yocona, MS
Milwaukee, Wl
Oconto, Wl
Yalobusha, Ml
Lower Kanawha, WV
Cattaraugus, NY
Saluda, SC
Des Plaines, IL
Upper White, IA
Lower Catawba, NC
case DO
1961-1965
(mg/L)
0.0000
1 .6000
0.2950
1 .0900
0.8800
0.6900
0.2000
0.5750
2.7600
2.9600
0.9400
2.6000
5.9500
0.0000
1.6000
0.0000
2.1800
0.5000
0.0000
0.0000
3.3000
1 .9500
1.7620
2.2267
1 .6780
case DO
1986-1990
(mg/L)
7.2200
8.3400
6.4967
7.1600
6.8400
6.4240
5.8600
5.9200
8.0500
8.0000
5.9400
7.5600
10.9000
4.9200
6.4800
4.8673
6.9567
5.2000
4.6160
4.5667
7.6000
6.2270
6.0000
6.3750
5.8000
DO
Change
(mg/L)
7.2200
6.7400
6.2017
6.0700
5.9600
5.7340
5.6600
5.3450
52900
5.0400
5.0000
4.9600
4.9500
4.9200
4.8800
4.8673
4.7767
4.7000
4.6160
4.5667
4.3000
4.2770
4.2380
4.1483
4.1220
Stations
1961-
1965
1
2
2
1
1
5
1
4
1
1
1
1
1
1
1
1
2
1
1
2
1
4
2
3
5
1986-
1990
1
2
24
1
1
1
1
3
1
1
1
1
1
7
2
3
3
1
4
3
2
10
1
2
1
3-23
-------
GO
i
ro
Figure 3-12
Location map and distribution chart of the 25 RF1 reaches with the greatest after-CWA improvements in worst-case DO. Source: USEPA STORET
12.5-r
10.0-
I
o
Q
O
%
o
7.5---
5.0-
0.0
n
n
n
n
n
_
n
\
„
_
n
n
_
n
After the CWA
n
n
-i_n
\
12345678 910111213141516171819202122232425
RF1 Reach Ranking (largest to smallest)
Catawba River \
O
I
•f
3
tt
I
(B
3'
I
I
2
1
-------
Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Catalog Unit Scale
Figures 3-13 and 3-14 are maps that display the locations and worst-case
DO concentrations of catalog units potentially eligible for the paired analysis for
the 1961-1965 and 1986-1990 time-blocks, respectively. The before-CWA data
set contained a total of 333 catalog units. The after-CWA data set had 905
catalog units.
In the before-CWA map (Figure 3-13),
• 45 of the 333 catalog units (14 percent) have worst-case DO less than
2.5 mg/L.
• 102 of the catalog units (31 percent) have levels from 2.5 to 5 mg/L.
• 186 of the catalog units (56 percent) are characterized by worst-case
DO greater than 5 mg/L.
In comparing these results with the historical data from the FWPCA
surveillance network (see Figure 3-2 in Section A of this chapter), many of the
catalog units characterized by poor DO conditions (DO less than 5 mg/L) in 1961-
1965 correspond to the areas represented by many of the stations compiled by
Gunnerson (1966) with minimum DO less than 0.5 and minimum DO between 0.5
and 4 mg/L in the 1957-1965 data set (see Figure 3-1).
In the after-CWA map (Figure 3-14),
• 49 of the 905 catalog units (5 percent) have worst-case DO less than
2.5 mg/L.
• 252 of the catalog units (28 percent) have levels from 2.5 to 5 mg/L.
• 604 of the catalog units (67 percent) are characterized by worst-case
DO greater than 5 mg/L.
Undesirable levels of worst-case DO (less than 5 mg/L) are still quite
prevalent after the CWA in some midwestern and southeastern watersheds, with
a pattern of moderately low worst-case DO (2.5 to 5 mg/L) that appears to be
characteristic of the Atlantic coastal plain from Florida to New Jersey. Higher
worst-case DO (5 to 7.5 mg/L) characterizes the Piedmont region and the
watersheds of the Appalachian Mountains and is likely due to cooler water
temperatures. The coastal plain pattern of moderately low worst-case DO most
likely reflects natural factors such as wanner summer temperatures, higher
decomposition rates, and relatively long residence times within sluggish rivers and
tidal waters rather than municipal or industrial point source loading within these
watersheds.
Overlaying the 333 eligible catalog units in the before-CWA data set with
the 905 eligible units in the after-CWA data set yielded a total of 246 intersecting
catalog units that had both before- and after-CWA data. Notably, these 246
evaluated catalog units represent a disproportionately high amount of urban/
industrial population centers, with approximately 61.6 million people represented
(32.5 percent of the total population served by POTWs in 1996). Figure 3-15
presents maps that display the locations and worst-case DO concentrations of the
evaluated catalog units. Figure 3-15(a) displays the catalog units that had im-
provement in worst-case DO after the CWA. Figure 3-15(b) displays the catalog
units that had degradation in worst-case DO after the CWA. Figure 3-16 presents
a frequency distribution of the before- and after-CWA data.
3-25
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Dissolved Oxygen (irgfL)
• 0-2.5
Figure 3-13
Locations and worst-case
DO concentrations of
catalog units potentially
eligible for the paired
analysis for the 1961-1965
time-block (before-CWA).
N = 333 catalog units.
Source: USEPA STORET
OsstAed Oxygen (n&L)
• 0- 2.5
Figure 3-14
Locations and worst-case
DO concentrations of
catalog units potentially
eligible for the paired
analysis for the 1986-1990
time-block (after-CWA).
N = 905 catalog units.
Source: USEPA STORET
3-26
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Figure 3-15
Locations and change in worst-case DO concentrations of evaluated catalog units where (a) shows improving units
(N = 167) and (b) shows degrading units (N = 79) before (1961-1965) versus after (1986-1990) the CWA.
Source: USEPA STORET
(a)
(b)
3-27
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-16
Frequency distribution
comparing worst-case DO
concentration of evaluated
catalog units before and
after the CWA. N = 246
catalog units.
Source: USEPA STORET
30 -
25 -
20 -
O>
15
13
O
•a
0)
'I 15
a.
O)
I
Q_
10 -
(n) = number of catalog units
• 1961-1965 (Before CWA)
E 1986-1990 (After CWA)
0 to 1 1 to 2 2 to 3 3 to 4 4 to 5 I 5 to 6 6 to 7 7 to 8 > 8
<- Undesirable levels >|< Desirable levels >
Worst-Case DO (mg/L)
Key observations from Figures 3-15 and 3-16 include the following.
• 167 (68 percent) of the 246 evaluated catalog units had increases in
worst-case DO after the CWA; 79 (32 percent) of the catalog units
had decreases in worst-case DO after the CWA.
• The percentage of evaluated catalog units characterized by "very low"
worst-case DO (< 2 mg/L) was reduced from 11 to 2 percent. Before
the CWA, 26 catalog units had very low worst-case DO; after the
CWA, only 6 catalog units had very low worst-case DO.
• The percentage of evaluated catalog units characterized by undesirable
worst-case DO (below the 5 mg/L threshold) was reduced from 47 to
26 percent. Before the CWA, 115 catalog units had undesirable levels
of worst-case DO; after the CWA, 65 catalog units had undesirable
levels of worst-case DO.
• The percentage of evaluated catalog units characterized by desirable
worst-case DO (above the 5 mg/L threshold) increased from 53 to 74
percent. Before the CWA, 131 catalog units had desirable levels of
worst-case DO; after the CWA, 181 catalog units had desirable levels
of worst-case DO.
Figure 3-17 is a column graph that describes the changes in worst-case DO
that occurred after the CWA for the 246 evaluated catalog units in relation to the
5 mg/L threshold. Key observations from this figure include the following:
• 67 percent of the evaluated catalog units (166 out of 246 units) re-
mained either above (47 percent) or below (20 percent) the 5 mg/L
worst-case DO threshold.
3-28
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
O)
o
re
4-1
re
O
re
Q.
14-
O
0)
O)
re
4-1
U
£
0)
a.
(n) = number of catalog units
Remained < 5 Remained >5 <5to>5 >5to<5
Change in Worst-Case DO After the CWA (mg/L)
Figure 3-17
Frequency distribution of
changes in worst-case DO
levels after the CWA using
5 mg/L as the threshold
value. N = 246 catalog
units.
Source: USEPA STORET
Of the 115 catalog units that had worst-case DO concentrations below
the threshold of 5 mg/L before the CWA, 57 percent (65 catalog units)
increased to above the threshold after the CWA.
• Of the 131 catalog units that had worst-case DO concentrations above
the benchmark threshold of 5 mg/L before the CWA, only 11 percent
(15 catalog units) fell below the threshold after the CWA.
Of the 246 evaluated catalog units with paired before- and after-CWA data,
167 catalog units (68 percent) had increased worst-case DO and 79 (32 percent)
had decreased worst-case DO after the CWA. Sections (a) and (b) of Figure 3-
18 display the magnitude of degradation and improvement, respectively. Key
observations from Figure 3-18 include the following:
• Approximately 32 percent of the evaluated catalog units that had
increases in worst-case DO (53 of the 167 improving catalog units)
increased by 2 mg/L or more.
• Approximately 13 percent of the evaluated catalog units that had
decreases in worst-case DO (10 of 76 degrading catalog units) de-
creased by 2 mg/L or more.
• Approximately 44 percent of all evaluated catalog units either stayed
the same or improved or degraded by 1 mg/L or less (108 of the 246
catalog units).
3-29
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-18
Frequency distribution of change in worst-case DO for evaluated catalog units that (a) decreased in concentration
(n = 79) and (b) increased in concentration (n = 167) before and after the CWA. Source: USEPA STORET
+- 30-
O)
o
re
+j
re
O
25-
20-
75 15-
0)
O)
re
*->
0)
H
0)
a.
10-
5-
(n) = number of catalog units
(0) (0) (0) (1) (1)
7to8 6to7 5to6 4to5 3to4 2to3 1to2 Oto1
(a)
Magnitude of Decrease in
Worst-Case DO After the CWA
Oto1 1to2 2to3 3to4 4to5 5to6 6to7 7to8
(b)
Magnitude of Increase in
Worst-Case DO After the CWA
Catalog Units with Greatest Improvements
Table 3-2 lists the 25 catalog units with the greatest before- and after-CWA
improvements in worst-case DO. Figure 3-19 presents a location map of the top
10 of these units along with a stacked column graph that shows their before- and
after-CWA worst-case DO concentration. Key observations from Table 3-2 and
Figure 3-19 include the following:
All of the top 25 catalog units with the greatest before- and after-CWA
improvements had before-CWA worst case DO levels below the
benchmark threshold of 5 mg/L. Four catalog units had a before-CWA
worst-case DO concentration of 0.0 mg/L.
For 20 of the 25 catalog units, after-CWA worst-case DO improved to
levels greater than 5 mg/L.
• The five catalog units that did not break the threshold value of 5 mg/L
after the CWA all had concentrations of 0.6 mg/L or less in the before-
CWA time-block.
3-30
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Table 3-2. Twenty-five catalog units with greatest improvements in worst-case (mean 10th percentile) DO
after the CWA.
Source: USEPA STORET
Worst- Worst-
case DO case DO DO
Catalog Unit 1961-65 1986-90 Change
Rank Reach ID Name (mg/L) (mg/L) (mg/L)
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
04030204
04120102
04110002
17010307
07070002
18060005
02050306
04030104
05080002
08030204
10170203
04040002
08030203
04040003
06010104
08030205
06010205
02040204
04100002
11070207
04040001
18090208
07120007
07130011
04100009
Lower Fox, Wl
Cattaraugus, NY
Cuyahoga, OH
Lower Spokane, WA
Lake Dubay, Wl
Salinas, CA
Lower Susquehanna, MD
Oconto, Wl
Lower Great Miami, IN
Coldwater, MS
Lower Big Sioux, IA
Pike-Root, IL
Yocona, MS
Milwaukee, Wl
Holston, TN
Yalobusha, MS
Upper Clinch, TN
Delaware Bay, NJ
Raisin, MI/OH
Spring, KS/MO
Little Calumet-Galie
Mojave, CA
Lower Fox, IL
Lower Illinois, IL
Lower Maumee, OH
0.1600
1 .3230
0.2950
3.5000
0.8800
3.1800
0.8800
0.5000
1.1850
0.0000
0.0000
0.9400
0.0000
2.1800
0.1570
0.0000
1.6140
0.5300
4.0588
1 .6000
0.5700
4.0200
3.7800
1 .9400
2.0676
7.2050
7.6000
6.5008
9.7000
6.6833
8.7500
6.1960
5.8000
6.4675
5.2082
5.1433
5.9400
4.8543
6.9567
4.8686
4.6295
6.0819
4.9100
8.3400
5.6250
4.5553
7.9767
7.5764
5.7225
5.8471
7.0450
6.2770
6.2058
6.2000
5.8033
5.5700
5.3160
5.3000
5.2825
5.2082
5.1433
5.0000
4.8543
4.7767
4.7116
4.6295
4.4679
4.3800
4.2812
4.0250
3.9853
3.9567
3.7964
3.7825
3.7795
3-31
-------
oo
ro
Figure 3-19
Location map and distribution chart of the 10 catalog units with the greatest before versus after-CWA improvements in worst-case DO. Source: USEPA STORET
Before the CWA
After the CWA
3456789 10
Catalog Unit Ranking
I
m
"*•
3'
f
I
to
I
!
Catalog units with improved worst-case DO
Catalog units with degraded worst-case DO
-------
Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Comparison of the Change in Signal Between the
Reach and Catalog Unit Scale Using the Upper
White River Basin (Indiana) as an Example
Recall that the underlying objective of the second leg of the three-legged
stool approach of this study was to measure the change in the response "signal"
linking point source discharges with downstream water quality before and after
the CWA at sequentially larger aggregations of spatial scales (reach, catalog unit,
and major river basin). The theory is that if a signal change can be detected at
sequentially larger scales, this would provide evidence that the CWA's technology-
and water quality-based effluent control requirements yielded broad as well as
localized benefits (that is, stream reaches both within and beyond the immediate
sag curve have benefited from the CWA).
The purpose of this subsection is to provide a practical comparison of reach
and catalog unit signals using worst-case DO from monitoring stations in the
Upper White River Basin (CU #05120201), the catalog unit in which the city of
Indianapolis, Indiana, and several smaller municipalities reside.
Background
In the 1960s the citizens of the city of Indianapolis depended on primary
treatment. Secondary treatment was added in the 1970s, and in 1983 the city
further upgraded its POTWs to advanced wastewater treatment (AWT) to
achieve compliance with water quality standards for DO. Two municipal facilities,
designed to treat up to 379 cfs (245 mgd), currently discharge effluent to the
White River. The base flow of the river is low; the 10-year, 7-day minimum
(7Q10) flow is about 50 cfs in the channel upstream of the two POTWs. Conse-
quently, under these low-flow conditions, Indianapolis's wastewater effluent
accounts for about 88 percent of the downstream flow.
In addition to Indianapolis, the 2,655-square-mile drainage area of the Upper
White River Basin contains several smaller municipalities that also discharge
municipal wastewater into the White River network. Population centers upstream
from Indianapolis include Muncie, Anderson, and Noblesville. Waverly, Centerton,
and Martinsville are towns located downstream of the city. Land use in the basin
includes agricultural uses (65 percent) and urban-industrial uses (25 percent), with
other uses accounting for the remaining 10 percent (Crawford and Wangness,
1991).
Using point and nonpoint source loading estimates of BOD5 for contempo-
rary conditions (16.3 metric tons/day ca. 1995) compiled for the NWPCAM
(Bondelid et al, 1999), municipal loads in the basin are estimated to account for
50 percent of the total loading to basin waterways. The remaining one-half of the
total BOD5 load is contributed by major and minor industrial sources (11 percent),
rural runoff (24 percent), urban runoff (13 percent), and CSOs (2 percent).
In a pre-AWT (1978-1980) and post-AWT (1983-1986) study of changes in
water quality of the White River following completion of the upgrade to AWT
from secondary activated sludge facilities for the city of Indianapolis, Crawford
and Wangness (1991) concluded that there were statistically significant improve-
ments in ambient levels of DO, BOD5, and ammonia-nitrogen downstream of the
upgraded municipal wastewater facilities. DO, in particular, improved by about 3
mg/L as a result of reductions in carbonaceous (BOD5) and nitrogenous (ammo-
3-33
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
nia) oxygen demands. For this study, Crawford and Wangness (1991) selected
monitoring stations located about 10 and 15 miles downstream of Indianapolis's
outfalls to collect data within the critical oxygen sag location of "degradation" and
"active decomposition" (Waverly) and the "recovery" zone (Centerton) (see
Figure 3-6).
During the before-CWA period from 1961 to 1965, streamflow conditions in
the Upper White River Basin were characterized as dry, with persistent drought
conditions for three consecutive summers from 1963 through 1965. During these
three summers, streamflow ratios ranged from 40 to 63 percent of the long-term
summer mean flow (see Figure 3-4(a) for 1963). Similarly, during the after-CWA
period of 1986-1990, the Upper White River Basin was affected by the severe
drought conditions of 1988 (streamflow ratio of only 34 percent of mean summer
flow) that extended over large areas of the Midwest, Northeast, and upper
Midwest (see Figure 3-4(b)). The hydrologic conditions of the White River are
particularly critical in assessing before and after changes in DO because the
municipal effluent flow of the upgraded AWT facilities (after 1983) accounted for
about 88 percent of the river flow downstream of Indianapolis under low-flow
conditions of the White River.
The Catalog-Level Signal
The analysis of before- and after-CWA worst-case DO data for the Upper
White River catalog unit revealed that this catalog unit improved by 1.75 mg/L,
from 3.80 mg/L (mean value of worst-case DO from 37 stations) before the
CWA to 5.55 mg/L (mean value of worst-case DO from 14 stations) after the
CWA. This level of improvement ranked it 64th out of the 246 catalog units with
before and after data sets (see Appendix D). A companion examination of BOD5
revealed that worst-case (90th percentile) loading in the catalog unit was reduced
from 34.8 mg/L before the CWA (1961-1965) to 6.9 mg/L after the CWA (1986-
1990).
The signal change detected provides evidence that
• The signal linking point source discharges with downstream water
quality inherently resides in the before- and after-CWA worst-case DO
data collected at stations throughout the Upper White River catalog
unit.
• The signal is strong enough to be detected using a catalog unit scale
summary statistic (mean of 10th percentile worst-case DO measure-
ments for stations within the catalog unit).
• Improved wastewater treatment by the city of Indianapolis, as well as
upgrades of wastewater treatment from small municipal facilities
throughout the basin, resulted in broad water quality improvements in
the Upper White River after the CWA.
The Reach-Level Signals
The POTW discharge/downstream water quality signal detected at the
catalog unit scale is, in reality, a statistical aggregation of signals associated with
all the monitored point source-influenced reaches in the Upper White River
watershed. If one breaks the catalog unit down and examines the before- and
3-34
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
after-CWA summary statistics for individual reaches, one would expect to find
that the reaches in the "degradation" and "active decomposition" zones have
more pronounced DO changes than reaches located outside those zones. An
examination of reaches in the Upper White River catalog unit revealed this theory
to be true. Figure 3-20 includes the locations and before- and after-CWA bar
charts for each of the seven reaches in the Upper White River that have paired
worst-case DO data. Figure 3-21 provides information regarding changes in
worst-case (90th percentile) BOD5 concentrations for the same reaches.
Key observations include the following:
• The reach with the greatest reduction of BOD5 and greatest improve-
ment in DO was the reach located immediately downstream of India-
napolis (05120201004) in the vicinity of Waverly. DO in this reach,
which ranked sixth out of 311 reaches with before and after DO data
nationwide (see Table 3-1), moved from 0.7 to 6.4 mg/L, an increase of
5.7 mg/L. In this same reach, the 90th percentile BOD5 concentration
declined from 58.1 mg/L to 4.3 mg/L.
• Reaches located immediately upstream of Indianapolis showed little
change in before- and after-CWA DO conditions (Eagle Creek
05120201032; White River 05120201007,05120201009; and Fall Creek
05120201006). BOD5, however, decreased from 20.6 to 7.0 mg/L in
reach 05120201007 and from 12.4 to 3.0 mg/L in reach 05120201009.
The decline in BOD5 levels most likely reflects upgrades in municipal
facilities for the small towns upstream of Indianapolis.
• Farther upstream, in the vicinity of Muncie and Anderson, greater
improvements in DO were detected (along with decreasing trends in
90th percentile BOD5 concentrations). In reach 05120201013
(Muncie), DO in the White River improved by 4.2 mg/L, from 2.2 mg/L
before the CWA to 6.4 mg/L after the act. In the compilation of 311
reaches with the greatest before and after improvements in DO, this
reach ranked 24th. For the reach in the vicinity of Anderson
(05120201011), located downstream of Muncie, DO improved by 2.8
mg/L, from 3.4 mg/L to 6.2 mg/L. This reach ranked 44th in the
nationwide ranking of stream reaches with DO improvements.
• The Lower White River catalog unit is located downstream from the
Upper White River unit. Before and after station records from the most
upstream reach of the basin reflect the impact of the wastewater
discharges from the small towns of Centerton and Martinsville, as well
as the recovery zone of the sag curve associated with the Indianapolis
point source inputs. In this recovery reach of the White River
(05120202031), DO improved by 1.9 mg/L, from 3.4 mg/L to 5.3 mg/L.
The aggregation of worst-case before- and after-CWA station records at
the reach scale produced a variety of signals. As expected, the signal linking point
source discharges with downstream water quality is most pronounced in reaches
located immediately below point source discharges (in the critical portion of the
sag zone). The signal became weaker farther downstream; however, in most
reaches it was detectable, especially in the recovery zone of the sag curve
associated with the Indianapolis discharges.
3-35
-------
CO
O)
White River IN (05120201009)
Upper White Basin IN (05120201)
10th Percentile
Dissolved Oxygen (mg/L)
! * 1 Before (1961-65)
IH After (1986-90)
(A
(A
*
o
§
I
i
(A
3'
I
I
I
-------
Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
(05120201006)
z
6
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3-37
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Major River Basins
The stations comprising the 311 reach-aggregated worst-case DO data
were pooled by the 18 major river basins of the contiguous United States for
statistical analyses of the significance of changes in DO concentration before and
after the CWA. These analyses were limited to the 311 evaluated reaches to
improve the assurance that the data were collected from the same sample
population.
Table 3-3 presents the number of observations, the results of the paired t-
test (95 percent confidence level), and the mean of the pooled before and after
worst-case DO data. The null hypothesis assumes that there is not a significant
difference between the mean concentrations for the before and after periods. The
means of the pooled worst-case DO data are presented as column graphs in
Figure 3-22.
Table 3-3. Statistical significance of trends in mean 1 0th percentile (worst-case) DO by major river basin:
before vs. after CWA (1 961 -1 965 vs. 1 986-1 990). Source: USEPA STORET.
Worst- Worst-
River Basin
All USA (01 -18)
01 - New England Basin
02 - Middle Atlantic Basin
03 - South Atlantic-Gulf
04 - Great Lakes Basin
05 - Ohio River Basin
06 - Tennessee River Basin
07 - Upper Mississippi Basin
08 - Lower Mississippi Basin
09 - Souris-Red Rainy Basin
10 - Missouri River Basin
11 - Arkansas-Red — White Basin
12 - Texas-Gulf Basin
13 - Rio Grande Basin
14 - Upper Colorado River Basin
15 - Lower Colorado River Basin
16 - Great Basin
17 - Pacific Northwest Basin
18 - California Basin
Paired f-test: 95% confidence - 2-sided test
Kolmogorov Smirnov test: 90% confidence,
'insufficient data for analysis
No. of
Paired
Reaches
311
1
17
61
26
66
19
48
25
2
10
7
2
0
1
0
2
17
7
2-s;ded test
Paired
f-test
Yes
*
Yes
Yes
Yes
Yes
Yes
Yes
No
*
No
No
*
*
*
*
*•
Yes
Yes
Kolmogorov
Smirnov
test
Yes
*
Yes
Yes
Yes
Yes
No
Yes
No
*
No
No
*
*
*
*
*
No
Yes
case DO
1961-1965
(mg/L)
4.56
4.30
2.80
4.10
3.85
5.40
4.08
3.80
3.79
5.65
5.76
5.36
5.77
-
4.88
-
7.45
7.61
5.61
case DO
1986-1990
(mg/L)
5.53
6.90
4.94
4.73
6.06
6.04
5.23
5.31
3.94
6.75
6.53
4.60
4.37
-
7.22
-
6.10
8.21
7.58
3-38
-------
Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Figure 3-22
Before vs. after trends in worst-case DO for major river basins: 1961-1965 vs. 1986-1990.
Source: USEPA STORET
O)
O
o
V
(0
O
+j
2
i
10
9 -
8 -
7 -
6 -
5
4
3 H
2
1 H
o
• 1961-1965 (Before CWA)
Q 1986-1990 (After CWA)
03
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-23
Statistical significance of the difference between before- and after-CWA worst-case DO mean values for the 18 major
river basins in the 48 contiguous states. Source: USEPA STORET
Shading indicates if there is a statistically x/"~~\ }
significant difference between the basin's \(
before- and after-CWA worst-case DO mean
values.
|U Yes, a statistically significant difference
Q No, not a statistically significant difference
| | Insufficient data for analysis
Figure 3-24 presents the before and after worst-case DO frequency distri-
butions for the mid-Atlantic, Great Lakes, Tennessee, and Upper Mississippi
major river basins. It is important to note that not only has the mean changed, but
the distribution has also changed. The frequency distributions shown in the figure
suggest that there have been improvements at the lower percentile levels of DO
(the 10th and 20th percentiles) for these river basins. Before the CWA in the
1961-1965 time block, worst-case DO was at 1 mg/L or lower. After the act,
worst-case conditions had improved to levels of about 3 to 5 mg/L.
The Kolmogorov-Smirnov test was used to statistically compare whether the
before and after distributions are significantly different. The Kolmogorov-Smirnov
test is a goodness of fit test that compares the empirical distributions from the two
time periods. Figure 3-24, showing the empirical cumulative distribution functions
of DO from the before and after periods, can be used to visualize what the
Kolmogorov-Smirnov test is comparing on a statistical basis. The vertical axis
presents the DO concentration corresponding to a given percentile on the horizon-
tal axis. Referring to the mid-Atlantic basin, for example, it can be seen that about
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Figure 3-24
Before- and after-CWA frequency distributions of worst-case DO aggregated by major river basin for reaches with paired before and after data sets:
(a) Middle Atlantic, (b) Great Lakes, (c) Tennessee River, and (d) Upper Mississippi River basins. Source: USEPA STORET.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
70 percent of the observations from the before period were less than 4 mg/L,
whereas in the after period only 30 percent of the observations were less than 4
mg/L. The Kolmogorov-Smirnov test is a statistical comparison of the maximum
distance between these curves. The results from the Kolmogorov-Smirnov test
are provided in Table 3-3.
Based on the two different statistical tests, and discounting the 7 river basins
with limited data, 8 of the 11 remaining river basins can be characterized by a
statistically significant improvement in worst-case DO using at least one of the
two tests. Mixed results (yes and no) were obtained for two basins with the
Kolmogorov-Smirnov test indicating no significant improvement for the Tennessee
(6) and the Pacific Northwest (17) basins, whereas the paired t-test indicated
significant improvements (yes) in these basins. Overall, there is a statistically
significant improvement in worst-case DO trends using both statistical tests at 6
out of 11 river basins with sufficient data. Of the five basins with at least one
"nonsignificant" change, three basins ( Missouri River, Arkansas Red-White, and
Pacific Northwest) had a mean worst-case pooled DO level greater than 5 mg/L
in the before time period and were less likely to be targeted for improved point
source pollution control. It is also noteworthy that in the 25-year interval between
the before- and after-CWA periods, there were no statistically significant condi-
tions of degradation of worst-case DO for any of the major river basins. It is also
noteworthy that when all 311 paired reaches are analyzed together, both tests
indicate significant increases in worst-case DO (see Figure 3-25 and top row (All
US A) of Table 3-3 ).
12
Figure 3-25
Before- and after-CWA
frequency distributions of
worst-case DO aggregated
over all major river basins
for the 311 reaches with
paired before and after
data sets.
Source: USEPA STORET.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
D. Summary and Conclusions
The purpose of this chapter is to address the second leg of the three-legged
stool approach for answering the question posed in Chapter 1—How has the
Nation's water quality changed since implementation of the 1972 CWA's
mandate for secondary treatment as the minimum acceptable technology for
POTWs? Recall that the basic goal of the second leg was to determine the extent
to which water quality improvements could be linked to the CWA's push for
secondary and greater levels of treatment in the Nation's POTWs. If evidence
showed that worst-case DO concentrations improved at broad, as well as local-
ized spatial scales, the second leg of the investigation could add cumulative
support for the conclusion that the CWA's mandates were successful. The
following objectives were established to guide this part of the study:
• Develop before- and after-CWA data sets composed of DO summary
statistics derived from monitoring stations screened for worst-case
conditions.
• Develop a worst-case DO summary statistic for each station for each
before- and after-CWA time period and then aggregate these data by
sequentially larger spatial scales (reaches, catalog units, and major river
basins).
• Conduct an analysis of the spatial units having both a before- and after-
CWA summary statistic and assess the magnitude of worst-case DO
change between the two time periods.
• Assess the change in the point source discharge/downstream DO
signal over the progressively larger spatial scales.
Key Points of the Background Section
Section A provided background concerning the source of DO data used in
this study, why worst-case conditions are an appropriate screening tool for
developing the before- and after-CWA data sets, and the role spatial scale played
in the second leg of this study. Key points include the following:
• The sharpest signal linking point source loading and downstream DO
inherently resides in data collected in worst-case (high temperature and
low flow) conditions. These worst-case conditions typically occur in the
summer months (July through September) during consecutive runs of
dry years (persistent drought).
• Widespread persistent drought was most pronounced in the summers in
1961-1965 (before the CWA) and 1986-1990 (after the CWA). These
time-blocks were used to define the before- and after-CWA time
periods for the comparison analysis.
• From a spatial perspective, worst-case critical, or minimum, DO below
a point source occurs in the "degradation" or "active decomposition"
zone of the oxygen sag curve. However, screening rules were not
developed to select monitoring stations located within these zones
because the goal of this second leg is to examine changes in the point
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
source discharge/downstream DO at broad scales as well as localized
scales. Consequently, the only screening rule regarding location of
stations eligible for the before- and after-CWA analysis is that the
station must be somewhere downstream and therefore potentially
influenced by a point source.
Key Points of the Data Mining Section
Section B presented the six-step data mining process used to create the
before- and after-CWA data sets to be used in the comparison analysis. The
screening rules associated with each step are listed below:
Step 1—Data Selection Rules
• DO, expressed as a concentration (mg/L), will function as the signal
relating point source discharges to downstream water quality re-
sponses.
• DO data are extracted only from the July-September (summer season)
time period.
• Only surface DO data (DO data collected within 2 meters of the water
surface) are used.
Step 2—Data Aggregation Rules From a Temporal Perspective
• 1961-1965 serves as the time-block to represent persistent drought
before the CWA and 1986-1990 serves as the time-block to represent
persistent drought after the CWA.
To remain eligible for the before- and after-CWA comparison, DO data
must come from a station residing in a catalog unit that had at least one
year classified as dry (streamflow ratio 75 percent of summer mean)
out of the 5 years in each before- and after-CWA time-block.
Step 3—Calculation of the Worst-case DO Summary Statistic
Rules
For each water quality station, the 10th percentile of the DO data
distribution from the before-CWA time period (July through September,
1961-1965) and the 10th percentile of the DO data distribution from the
after-CWA time period (July through September, 1985-1990) are used
as the station's DO worst-case statistics for the comparison analysis.
• To remain eligible for the before- and after-CWA statistical compari-
son, a station must have a minimum of eight DO measurements within
each of the 5-year time-blocks.
Step 4—Spatial Assessment Rules
• Only water quality stations on streams and rivers affected by point
sources are included in the before- and after-CWA comparison analy-
sis.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Step 5—Data Aggregation Rules From a Spatial Perspective
The before- and after-CWA data sets are collections of DO summary
statistics that characterize worst-case DO at individual water quality
monitoring stations across the United States for the 1961-1965 time-
block and the 1986-1990 time-block, respectively (one DO summary
statistic per station per time-block).
• For each data set and time-block, the 10th percentile value from each
eligible station is aggregated within the spatial hydrologic unit. (Since
the scales are hierarchical, a station's summary statistic is effectively
assigned to a reach and a catalog unit.) A summary statistic is then
calculated and assigned to the spatial unit for the purpose of character-
izing its worst-case DO. If a spatial unit has only one monitoring station
within its borders that meets the screening criteria, the 10th percentile
DO value from that station simply serves as the unit's worst-case
summary statistic. If, however, there are two or more stations within a
spatial unit's borders, the 10th percentile values for all the eligible
stations are averaged and this value is used to characterize worst-case
DO for the unit.
• The mean 1 Oth percentile value is computed from the eligible station's
10th percentile values for the before- and after-CWA periods.
Step 6—Development of the Paired Data Sets (at each spatial
scale)
• To be eligible for the paired comparison analysis, a hydrologic unit must
have both a before-CWA and an after-CWA summary statistic as-
signed to it.
Key Points of the Comparison Analysis Section
Section C presented the results of the comparative before- and after-CWA
analysis of worst-case DO data derived using the screening criteria described in
Section B and aggregated by spatial units defined by three scales (reach, catalog
unit, and major river basin). Listed below are key observations for each spatial
scale.
Reach Scale
• Sixty-nine percent of the reaches evaluated showed improvements
in worst-case DO after the CWA. [Three hundred eleven reaches (out
of a possible 12,476 downstream of point sources) survived the data
screening process with comparable before- and after-CWA DO
summary statistics. The number of reaches available for the paired
analysis was limited by the historical data for the 1961-1965 period].
• These 311 evaluated reaches represent a disproportionately high
amount of urban/industrial population centers, with approximately 13.7
million people represented (7.2 percent of the total population served by
POTWs in 1996). The top 25 improving reaches saw their worst-
case DO increase by anywhere from 4.1 to 7.2 mg/L!
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
• The number of evaluated reaches characterized by worst-case DO
below 5 mg/L was reduced from 167 to 97 (from 54 to 31 percent).
• The number of evaluated reaches characterized by worst-case DO
above 5 mg/L increased from 144 to 214 (from 46 to 69 percent).
Catalog Unit Scale
• Sixty-eight percent of the catalog units evaluated showed improve-
ments in worst-case DO after the CWA. [Two hundred forty-six
catalog units (out of a possible 1,666 downstream of point sources)
survived the data screening process with comparable before- and after-
CWA DO summary statistics].
The number of evaluated catalog units characterized by worst-case
DO below 5 mg/L was reduced from 115 to 65 (from 47 to 26 per-
cent). The number of evaluated catalog units characterized by worst-
case DO above 5 mg/L increased from 131 to 181 (from 53 to 74
percent).
• Fifty-three of the 167 improving catalog units (32 percent) improved by
2 mg/L or more while only 10 of 79 degrading catalog units (13 per-
cent) degraded by 2 mg/L or more.
• These 246 evaluated catalog units represent a disproportionately high
amount of urban/industrial population centers, with approximately 61.6
million people represented (32.5 percent of the total population served
byPOTWsin 1996).
Major River Basin Scale
• A total of 11 out of 18 major river basins had sufficient reach-aggre-
gated worst-case DO data for a before- and after-CWA comparison
analysis.
• Based on two statistical tests, 8 of the 11 major river basins can be
characterized as having statistically significant improvement in worst-
case DO levels after the CWA. The three basins that did not statisti-
cally improve under either test also did not have statistically significant
degradation.
• When all the 311 paired (i.e., before vs. after) reaches were aggre-
gated and the statistical tests run on all 18 of the major river basins of
the contiguous states as a whole, worst-case DO also showed signifi-
cant improvement.
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
Conclusions
The statistical analyses developed for this study are not ideal. One
major concern is the potential bias introduced in the ambient monitoring
programs used to collect the data archived in STORET. It is believed that
the analysis of data sets with data in the before and after time periods
alleviates some of these concerns and that results are generally comparable
for the two different statistical tests. Based on the systematic, peer-re-
viewed approach designed to identify and evaluate the national-scale
distribution of water quality changes that have occurred since the 1960s, this
study has compiled strong evidence that the technology- and water quality-
based policies of the CWA for point source effluent controls have been
effective in significantly improving DO. In this retrospective analysis, DO
was used as the key indicator because the reduction of organic carbon and
nitrogen (BODu) loading from municipal and industrial point sources was
one of the major goals of the CWA's technology-based policy, which re-
quired industrial effluent limits and a minimum level of secondary treatment
for municipal facilities. Based on ambient DO records, significant before and
after improvements in many rivers and streams have been identified over
national, major river basin, catalog unit, and reach-level spatial scales.
The "signal" of downstream water quality responses to upstream
wastewater loading and the changes in this signal since the 1960s has been
successfully decoded from the "noise" of millions of archived water quality
records. Given the very large spatial scale of the major river basins, it is remark-
able to observe statistically significant before and after DO improvements as
detected using the systematic methodology described herein. Previous evaluations
of the effectiveness of the CWA (e.g., Smith et al., 1987a, 1987b, 1992; Knopman
and Smith, 1993) were not able to report conclusively significant improvements in
DO. In these earlier studies, however, the methodologies used were not specifi-
cally designed to separate the signal of downstream water quality response from
the noise within large national databases. Using appropriate data screening rules
and spatial aggregations, it has been demonstrated that improvements in water
quality, as measured by improvements in worst-case DO, have been achieved
since the 1960s.
The findings of this national-scale water quality assessment demonstrate
three important points:
• As new monitoring data are collected, it is crucial for the success of
future performance measure evaluations of pollution control policies
that the data be submitted, with appropriate QA/QC safeguards, to
accessible databases. If the millions of records archived in STORET
had not been readily accessible, it would have been impossible to
conduct this analysis to identify the signals of water quality improve-
ments that have been achieved over the past quarter-century.
• Significant after-CWA improvements in worst-case summer DO
conditions have been quantitatively documented with credible statistical
techniques in this study over different levels of spatial data aggregation
from the small subwatersheds of Reach File Version 1 river reaches
(mean drainage area of approximately 115 mi2) to the very large
watersheds of major river basins (mean area of 434,759 mi2).
Conclusion of
There were significant
after-CWA improvements
in worst-case summer DO
conditions in two-thirds of
the hydrologic units at all
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
• The data mining and statistical methodologies designed for this study
can potentially be used to detect long-term trends in signals for water
quality parameters other than DO (e.g., suspended solids, nutrients,
toxic chemicals, pathogens) to develop new performance measures to
track the effectiveness of watershed-based point source and nonpoint
source controls. The key element needed to apply the data mining
methodology to other water quality parameters is the careful specifica-
tion of rules for data extraction that reflect a thorough understanding of
the various processes that influence the spatial and temporal distribu-
tions of a water quality constituent, as well as the relevant sources of
associated pollutants.
Population Affected by Reaches With Improved DO
To monetize environmental benefits derived from various environmental
policy decisions, USEPA developed the NWPCAM model (Bondelid et al., 1999),
which includes a link between 1990 population and RF1 reaches. As discussed in
Section E, this model does not include all estuarine and coastal waters, and as a
result, does not account for the entire US population. It is estimated that about
one-third of the U.S. population is not accounted for in the model. At the same
time if a person is located near two rivers, that person is counted twice since he
or she can derive a benefit from environmental improvements in either river.
Recognizing this accounting procedure, the model accounts for 197.7 million
people in 23,821 reaches. In the 311 reaches analyzed here (1.3 percent of
reaches in the model), the model accounts for 13.7 million people (6.9 percent of
the population in the model). The ratio of the percent population to percent
reaches in the model demonstrates that the screening process developed for this
analysis is reasonably successful in finding reaches with data near urban centers,
although 57 of the 311 reaches did not have population associated with them. Of
the 13.7 million people represented by the 311 reaches, 11.8 million of them (86
percent) are associated with reaches that have an increased worst-case DO from
before to after the CWA. Almost one-half (45 percent) of the selected population
are associated with reaches that went from worst-case DO below 5 mg/L before
the CWA to greater than 5 mg/L after the CWA. Although it is unfortunate that
more reaches are not considered in the current analysis (mainly because of
limitations in available monitoring data for the before-CWA periods), it is helpful to
consider that the corresponding 246 catalog units include 61.6 million (31.2
percent) of the 197.7 million people accounted for in the model. And three-fourths
(46.5 million) of the 61.6 million people are in catalog units that had an increase in
worst-case DO between the before to after time period.
Sensitivity to Using DO versus Percent Saturation
The beginning of this chapter describes the physical processes associated
with atmospheric reaeration, oxygen demand, and dilution, as well as the impact
of changing water temperatures and elevation. During the initial development of
the screening methodology, considerable effort was spent evaluating various
indicators for water quality. Ultimately, DO was selected. Another strong candi-
date was DO expressed as percent saturation. Use of percent saturation would
effectively normalize the DO data to account for geographic differences in
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
elevation, chlorides, and water temperature. Saturation levels of DO decrease
with higher elevations, increasing chloride content, and warmer water tempera-
tures (Chapra, 1997). Correcting for elevation would improve spatial comparisons
such as those in Figures 3-13 through 3-15, and correcting for chlorides and water
temperature would account for some of the unexplained variability that might exist
between the before and after time periods.
To evaluate the impact that selection of DO over DO as percent saturation
might have on the analysis, two scatter plots with data aggregated to the reach
level were compared. Figure 3-26(a) presents the DO after the CWA as a
function of DO before the CWA. Figure 3-26(b) presents the DO (percent
saturation) after the CWA as a function of DO (percent saturation) before the
CWA aggregated to the reach level. The values for DO (percent saturation) were
computed using the same procedure used for DO. Points above the diagonal line
in either figure indicate that the DO or DO (percent saturation) increased.
Although the two figures use different scales, a visual comparison suggests that
there would be little difference if DO (percent saturation) were adopted over DO.
Given that the public has a more intuitive understanding of DO measured as
concentration, the analysis in this chapter uses DO concentration rather than
percent saturation.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 3-26
(a) Comparison of the 10th
percentile DO before the
CWA as a function of the
10th percentile DO after
the CWA. (b) comparison
of the 10th percentile DO
(percent saturation) before
the CWA as a function of
the 10th percentile DO
(percent saturation) after
the CWA.
Source: USEPA STORET.
(a)
DO Before the CWA (mg/L)
(b)
DO Before the CWA (% Saturation)
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Chapter 3: An Examination of "Worst-Case" DO in Waterways Below Point Sources Before and After the CWA
References
Ackerman, W.C., Harmeson, R.H., and Sinclair, R.A. 1970. Some long-term
trends in water quality of rivers and lakes. Transactions of the American
Geophysical Union, vol. 51, page 516-522.
Bondelid, T., C. Griffiths, and G. van Houten. 1999. A national water pollution
control assessment model. Draft tech. report prepared by Research Tri-
angle Park, NC for U.S. Environmental Protection Agency, Office of
Science and Technology, Washington, DC.
Chapra, S.C. 1997. Surface Water Quality Modeling. McGraw Hill, Inc. New
York, NY.
Crawford, C.G., and D.J. Wangness. 1991. Effects of advanced wastewater
treatment on the quality of White River, Indiana. Water Resources Bulletin
27(5): 769-779.
Gunnerson, C.G. 1966. An atlas of water pollution surveillance in the United
States, Otober 1, 1957 to September 30, 1965. Water Quality Activities,
Division of Pollution Surveillance, Federal Water Pollution Control
Adminstration, U.S. Department of the Interior, Cincinnati, OH.
Knopman, D.S. and R.A. Smith. 1993. Twenty years of the Clean Water Act:
Has U.S. water quality improved? Environment 35(1): 17-41.
Smith, R.A., R.B. Alexander, and M.G. Wolman. 1987a. Analysis and interpre-
tation of water quality trends in major U.S. rivers, 1974-81. Water-
Supply Paper 2307, U.S. Geological Survey, Reston, VA.
Smith, R.A., R.B. Alexander, and M.G. Wolman. 1987b. Water quality trends in
the Nation's rivers. Science 235 (27 March 1987):1607-1615.
Thomann, R.V., and J.A. Mueller. 1987. Principles of surface water quality
modeling and control. Harper & Row, New York, NY.
USEPA. STOrage and RETrieval Water Quality Information System. U.S.
Environmental Protection Agency, Office of Wetlands, Oceans, and Water-
sheds, Washington, DC.
USEPA. 1974. National water quality inventory, 1974. EPA-440/9-74-001.
U.S. Environmental Protection Agency, Office of Water Planning and
Standards, Washington, DC.
Wolman, A. 1971. The Nation's rivers. Science 174:905-918.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
3-52
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Chapter 4
Case Study Assessments
of Water Quality
In the previous chapter, the national-scale evaluation of long-term trends in
water quality conditions identified numerous waterways that were character-
ized by substantial improvements in worst-case DO after the CWA (from
1961-1965 to 1986-1990). The signals of worst-case DO improvements that have
been detected from the "noise" of the STORET database document the tremen-
dous progress that has been achieved as a result of implementation of the CWA in
1972. Having identified numerous watersheds and RF1 reaches, however, the
inquisitive reader could easily list a number of questions to fill in the information
needed to tell a more complete history about environmental management and
water pollution control decisions in these watersheds.
Typical questions might include the following: What are the population
trends? Are point or nonpoint sources the largest component of pollutant loading?
What have been the long-term trends in effluent loading from municipal and
industrial sources over the past 25-50 years? Has industrial wastewater loading
declined because obsolete manufacturing facilities have been abandoned? What
have been the long-term trends in key water quality parameters over the past 25-
50 years? Have reductions in wastewater loads had any impact on biological
resources or recreational activities?
This third leg of the three-legged stool approach focuses on answering these
types of questions. The uniqueness of each watershed requires an investigator to
go beyond STORET and other centralized databases to identify, obtain, and
compile sufficient historical data to answer these questions and others. By
necessity, the selection of specific waterways based on case studies has often
been used as an appropriate technique for policy evaluations of the environmental
effectiveness of water pollution control decisions. That technique is used in
Chapters 5 through 13 of this document.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
A. Background
Less than a decade after enactment of the 1972 CWA, Congress and the
public began to raise policy questions about the national-scale effectiveness of the
technology-based controls of the CWA. In attempting to provide some answers to
these questions, case studies of water pollution control and water quality manage-
ment were compiled for a number of streams, rivers, lakes, and estuarine water-
bodies. To meet a variety of objectives, both anecdotal and quantitative data and
information have been collected for case studies evaluating water quality condi-
tions.
Anecdotal accounts of historical water pollution problems and changes in the
water quality of streams, rivers, estuaries, and coastal waters that had been
achieved by the early 1980s were reported by state agencies and compiled by
USEPA (1980) and the Association of State and Interstate Water Pollution
Control Administrators (ASIWPCA, 1984). Twenty-five years after enactment of
the 1972 CWA, USEPA (1997) and the Water Environment Federation (WEF,
1997) reported on the substantial water quality improvements that had been
achieved in rivers, lakes, estuaries, and coastal waters. Based on anecdotal
evidence, these reports concluded that the CWA had produced substantial gains in
water quality. No quantitative data were presented, however, in either of these
reports to support the conclusion that the goals of the CWA were being achieved.
In a 1988 quantitative synthesis of before-and-after studies, USEPA (1988)
compiled the results of 27 case studies to document water quality changes that
had resulted from upgrades to municipal wastewater treatment facilities (primary
to secondary, or secondary to advanced treatment). With the exception of only a
few cases (e.g., Potomac estuary near Washington, DC, and Hudson River near
Albany, New York), most of the 27 cases accounted for both minor and major
facilities (< 0.1 to 30 mgd) discharging to small receiving waters with 7Q10 low
flows ranging from < 1 cfs to 100 cfs. Based on pollutant loading and water
quality data sets, 23 of the 27 case studies were characterized by at least moder-
ate improvements in water quality conditions after upgrades of the POTWs.
Included in USEPA's 1988 synthesis were the well-documented before-and-after
findings of Leo et al. (1984), based on 13 case studies of water quality changes
that were linked to upgrades from secondary to advanced treatment. Also
included in USEPA's synthesis were four case studies prepared by GAO (1986a)
of municipal upgrades for rivers in Pennsylvania: Lehigh River, Allentown (30
mgd); Neshaminy Creek, Lansdale (2.36 mgd); Little Schuykill River, Tamaqua
(1.09 mgd); and Schuykill River, Hamburg (0.46 mgd).
A number of case studies other than those presented in this report have
documented trends in improvements in water quality conditions and biological
resources following site-specific upgrades. Estuarine case studies of pollutant
loading, water quality trends, fisheries, and other biological resources have been
prepared for Narragansett Bay (Desbonnet and Lee, 1991), Galveston Bay
(Stanley, 1992a), the Houston Ship Channel (EESI, 1995), and Pamlico-Albemarle
Sound (Stanley, 1992b).
For Lake Washington in Seattle, Edmondson (1991) documented the long-
term ecological impact of the diversion during the mid-1960s of municipal waste-
water on cultural eutrophication and recovery of a large urban lake. The rejuve-
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Chapter 4: Case Study Assessments of Water Quality
nation of Lake Erie, declared "dead" during the 1960s, is positive evidence that
the regulatory controls of the 1972 Clean Water Act and the 1972 Great Lakes
Water Quality Agreement between Canada and the United States, designed to
mitigate bottom water hypoxia and cultural eutrophication by reducing pollutant
loads of organic matter and phosphorus, have been successful in greatly improv-
ing water quality (Burns, 1985; Charlton et al., 1995; Sweeney, 1995) and ecologi-
cal conditions (Krieger et al., 1996; Koonce et al., 1996; Makarewicz and
Bertram, 1991) in this once ecologically devastated lake. The Cuyahoga River, a
major tributary to Lake Erie at Cleveland, Ohio, sparked national attention when
the river caught fire in 1969, helping to push the U.S. Congress to pass the Clean
Water Act in 1972 (NGS, 1994). Three decades after the infamous fire, although
some water quality problems remain to be solved (e.g., urban runoff and CSOs),
water quality is greatly improved. Tourist-related businesses and recreational uses
along the riverfront are thriving, as are populations of herons, salmon, walleye,
and smallmouth bass (Hun, 1999; Brown and Olive, 1995).
In freshwater river systems, Isaac (1991) presented long-term trends (1969-
1980) of DO in the Blackstone, Connecticut, Hoosic, and Quinebaug rivers in
Massachusetts to document water quality improvements after upgrades of
municipal facilities to secondary treatment. Using a wealth of historical data
compiled for New England, Jobin (1998) presents a number of case studies
documenting long-term trends in pollutant loading and water quality for freshwater
rivers (e.g., Neponset, Charles, Taunton, Blackstone) and estuarine systems (e.g.,
Boston Harbor, Narragansett Bay). In the Midwest, Zogorski et al. (1990)
prepared a case study of the Upper Illinois River basin to evaluate the availability
and suitability of water quality and effluent loading data as a demonstration of the
methodology for use in national assessments of water quality trends. Zogerski et
al. concluded that although a large amount of the required data is available from
national and state databases, "the suitability of the existing data to accomplish
the objectives of a national water-quality assessment is limited."
In another midwestern river, a statistical before-and-after analysis of water
quality in the White River near Indianapolis, Indiana, clearly showed improve-
ments in DO, ammonia, and BOD5 after an upgrade from secondary to advanced
treatment (Crawford and Wangness, 1991). (See discussion in Chapter 3.) Similar
water quality improvements have also been documented for the Flint River in
Georgia and the Neches River in Texas (Patrick et al., 1992). Becker and Neitzel
(1992) have compiled case studies of the impacts from water pollution and other
human activities on water quality, fisheries, and biological resources for a number
of major North American rivers. Another success story in the Pacific Northwest
has documented both water quality and economic benefits achieved by water
pollution control in the Boise River in Idaho (Hayden et al., 1994; Noah, 1994).
4-3
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
B. Selection of Case Study Waterways
Following the precedent established by these earlier before-and-after
assessments of changes in water quality that can be attributed, in part, to the
CWA, a number of freshwater and estuarine waterbodies were selected as case
studies for this report. Criteria for the selection of case study sites included the
following:
• The major river or estuarine system was identified in the 1960s as
having gross water pollution problems.
• The major river or estuarine system lies in a major urban-industrial
region.
Municipal wastewater is a significant component of the point source
pollutant load to the system.
• Water quality models were available to evaluate the water quality
impact of simulated primary, secondary, and actual effluent scenarios
for municipal dischargers.
• Historical data were readily available.
Table 4-1 provides the 1996 population for the Metropolitan Statistical Areas
(MSAs) and counties included in the case study, and the types of data and
information compiled for each river or estuarine waterbody selected as a case
study. The population of the case study MSAs (43.2 million) accounted for 16
percent of the Nation's total population in 1996 (265.2 million) (USDOC, 1998).
Figure 4-1 shows the location of the case study watersheds. In contrast to some
of the other case study assessments discussed previously, the case studies in this
report were specifically selected because they represent large cities located on
Table 4-1. Case study assessments of trends in water quality and environmental resources.
(Source: USDOC, 1998)
Case Study
Connecticut
River
Hudson-
Raritan Estuary
Delaware
Estuary
Potomac
Estuary
James Estuary
Upper
Chattahoochee
River
Ohio River
Upper
Mississippi
River
Willamette
River
1996 Study Area
Population
(millions)
1.109
16.991
5.973
4.635
2.237
3.528
3.779
2.760
2.149
Information Presented
Population
/
/
/
/
/
/
/
/
/
Pollutant
Loads
/
/
/
/
/
/
/
/
/
Water
Quality
/
/
/
/
/
/
/
/
/
Environmental
Resources
/
/
S
/
/
/
/
/
/
Recreational
Uses
/
/
/
/
/
/
/
/
/
Water Quality
Model
/
/
/
/
4-4
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Chapter 4: Case Study Assessments of Water Quality
2. Hudson-Rantan
estuary
8. Upper Mississippi River j
6. Chattahoochee River
Figure 4-1. Location of case study watersheds.
major waterways known to have been plagued by serious water pollution prob-
lems during the 1950s and 1960s (Table 4-2). Many of the case study waterways
either were the sites of interstate enforcement conferences from 1957 to 1972 or
were listed by the federal government as being potential waterways to convene
state-federal enforcement conferences in 1963 (Zwick and Benstock, 1971). Two
of the case studies, the Ohio River and tributaries to New York Harbor (Passaic
River and Arthur Kill), were identified by the federal government in 1970 in a list
of the top 10 most polluted rivers (Zwick and Benstock, 1971). The Department
of the Interior identified all the estuarine case study sites as waterways suffering
from either low oxygen levels or bacterial contamination in a national study of
estuarine water quality (USDOI, 1970). All but two of the case study areas were
the subject of water quality evaluation reports prepared for the National Commis-
sion on Water Quality (NCWQ) to provide baseline data to track the effective-
ness of the technology-based effluent controls required under the newly enacted
1972 CWA (see Mitchell, 1976).
For all the case studies, data have been compiled to characterize long-term
trends (more than 50 years) beginning in 1940 for population, upgrades to munici-
pal wastewater facilities, effluent loading, water quality, environmental resources,
and recreational uses. Additional data have been obtained from validated water
quality models for the Upper Mississippi River, Potomac estuary, Delaware
estuary, and James estuary to quantify improvements in water quality achieved by
municipal upgrades from primary to secondary or advanced treatment levels.
Data sources include published scientific and technical literature, USEPA's
STORET database, and unpublished technical reports ("grey" literature) prepared
by consultants and state, local, and federal agencies.
4-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 4-2. Identification of gross water pollution problems for case study waterways in government
documents. Sources: Zwick and Benstock, 1971; USDOI, 1970; and Mitchell, 1976.
Case Study
Connecticut River
Hudson-Raritan estuary
Delaware estuary
Potomac estuary
James estuary
Chattahoochee River
Ohio River
Upper Mississippi River
Willamette River
Potential
Enforcement
Conference
1963
•
•
•
•
•
•
Enforcement
Conference
1957-72
•
•
•
•
•
•
Top 10
Polluted
Waterways
1970
•
•
NCWQ
Case
Studies
1976
•
•
•
•
•
•
•
National
Estuarine
Pollution Study
1970
•
•
•
•
•
C. Before and After CWA
Using water quality data extracted from USEPA's STORET database (as
described in Chapter 3), before-and-after conditions for summer (July-Septem-
ber), 10th percentile DO levels in RF1 reaches selected from the case study
watersheds (Figure 4-1) clearly demonstrate dramatic improvements during the
period after the CWA from 1986-1995 for all the case study sites (Figure 4-2).
Before the CWA, during the 10-year period from 1961 to 1970, "worst-case" DO
levels were in the range of 1 to 4 mg/L for most of the case study sites. After the
CWA, worst-case DO levels had improved substantially to levels of about 5 to 8
mg/L during 1986-1995, with the worst-case oxygen levels of less than 2 mg/L
before the CWA improving to 5 mg/L or higher after the CWA. Great progress
has been achieved in improving DO conditions in New York Harbor, the
Chattahoochee River, the Delaware River, and the Potomac River.
Water quality improvements in other constituents, including BOD5, sus-
pended solids, coliform bacteria, heavy metals, nutrients, and algal biomass, have
also been linked to reductions in municipal and industrial point source loads for
many of the case studies. Figure 4-3 correlates long-term trends in the reduction
of effluent loads of BOD5 with improvements in summer DO in the Upper
Potomac estuary (Washington, DC), the Upper Mississippi River (Minneapolis-St.
Paul, MM), and the Willamette River (Portland, OR). Finally, improvements in
water quality have also been linked to the post-CWA restoration of important
biological resources (e.g., fisheries and submersed aquatic vegetation in the
Potomac estuary) and increased recreational demand and aesthetic values of
waterways once considered extremely unsightly (e.g., Upper Mississippi River).
4-6
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Chapter 4: Case Study Assessments of Water Quality
Figure 4-2
Location map of case study waterways and distribution chart of their before- and after-CWA mean 10th percentile DO
for case study RF1 reaches: 1961-1970 vs. 1986-1995. Source: USEPA STORET.
3. Delaware estuary
1. Connecticut River
9. Willamette River |
4. Potomac estuary
8. Upper Mississippi River |
5. James estuary I
6. Chattahoochee River
Before the CWA
After the CWA
234567
Case Study Waterway Number
4-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 4-3. Long-term trends of improvements in ambient DO and declines in effluent BOD5 loading for (a) Upper
Potomac estuary, (b) Upper Mississippi River, and (c) Willamette River. Sources: Larson, 1999; Gleeson, 1972;
Jaworksi, 1990; MWCOG, 1989; ODEQ, 1970; USEPA STORET.
(a)
Upper Potomac Estuary
Washington DC
100
1970
1980
1990
(b)
Upper Mississippi River
Minneapolis-St. Paul, Minnesota
10
5-
__„
^--*"
Oxygen
p
1
s
s
s
/
A
s
/
•
/
/
\
1
1
1
1
1
1
1
1
Ef
„-- \,
F!uent BODS
/
IN
"''--o
150
100
50
(c)
I
in
1940 1950 1960 1970 1980 1990
Lower Willamette River
Portland, Oregon
1
\
*t*t
*
Munic
» Industrial
i Municipa
V\.
A
>±jjjf~
pal
4.
^
"""•-.
w
Oxygen
^
1
I
D>
r2oo e
S
to
Q
o
100 ;
-n
1940 1950 1960 1970 1980 1990
D. Policy Scenarios for Municipal Effluent
Discharges
Before the 1972 CWA, state officials made waterbody-dependent decisions
about the required level of municipal wastewater treatment needed to attain
compliance with ambient water quality criteria or standards. After the 1972 CWA,
the USEPA implemented a technology-based policy to regulate pollutant loading
from municipal and industrial point sources. Under the 1972 CWA, municipalities
were required to achieve at least a minimum level of secondary treatment to
remove approximately 85 percent of the oxygen-demanding material from waste-
water. In cases where the minimum level of secondary treatment was not suffi-
cient to meet water quality criteria or standards, ambient criteria were used to
determine a water quality-based level of wastewater treatment greater than
secondary treatment. From a policy and planning perspective, the key question for
water quality management decision makers is: What level of municipal wastewa-
ter treatment is needed to ensure compliance with water quality criteria or
standards under critical conditions?
4-8
-------
Chapter 4: Case Study Assessments of Water Quality
For the Delaware, Potomac, James, and Upper Mississippi case studies,
validated water quality models have been used to provide quantitative answers to
evaluate the changes in water quality conditions achieved as a result of either
actual or hypothetical upgrades to municipal wastewater treatment facilities.
Effluent loading rates for the primary and secondary loading scenarios were
based on existing population served and effluent flow data with typical effluent
concentrations characteristic of primary and secondary treatment facilities;
existing loading rates were used to define the better-than-secondary (actual)
scenario. Receiving water streamflow was based on the existing "dry" summer
streamflow measurements used to validate the models. The water quality models
were used to simulate the impact of the primary, secondary, and actual better than
secondary loading scenarios on the spatial distributions of DO, BOD5, nitrogen,
phosphorus, and algal biomass.
Figure 4-4 shows the key results for the model simulations for dissolved
oxygen simulated at the worst-case critical oxygen sag location along the length
(a)
OJ
O)
>
X
O
•o
_
o
(A
in
Delaware Estuary Model
July 1976 conditions, river mile 96
5.0 mg/L (benchmark for defining
desirable vs. undesirable levels of DO
03) Potomac Estuary Model
September 1983 conditions, river mile 105
10-1
(c)
Primary Secondary >Secondary
Municipal Effluent Scenario
James Estuary Model
September 1983 conditions, river mile 90
(d)
Primary Secondary >Secondary
Municipal Effluent Scenario
Upper Mississippi Model
August 1988 conditions, river mile 830
Primary Secondary >Secondary
Municipal Effluent Scenario
Primary Secondary >Secondary
Municipal Effluent Scenario
Figure 4-4. Model simulation of DO under summer "dry" streamflow conditions at the critical oxygen sag location for
primary, secondary and better-than-secondary effluent scenarios for case studies of (a) Delaware estuary,
(b) Potomac estuary, (c) James estuary, and (d) Upper Mississippi River. Sources: Clark et a/., 1978; Fitzpatrick et a/,,
1991; HydroQual, 1986; Lung, 1998; Lung and Larson, 1995; Lung and Testerman, 1989.
4-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Conclusion of
of the stool
of each river. As shown in these results, the primary effluent scenario results in
extremely poor conditions with DO levels of less than 1 mg/L for the Potomac,
James, and Upper Mississippi cases and 2 mg/L for the Delaware. The model
results for the primary scenario of severe oxygen depletion are, in fact, consistent
with historical oxygen data recorded for these rivers during the 1960s. Simulating
an upgrade to secondary treatment, as mandated by the 1972 CWA for municipal
facilities, DO conditions are improved but are still less than the benchmark
concentration of 5 mg/L often used to describe compliance with water quality
standards. As demonstrated with the models, and actually achieved, better-than-
secondary levels of municipal treatment are needed to exceed a benchmark of 5
mg/L for DO. In contrast to the poor water quality conditions common in these
rivers during the 1960s, the occurrence of low DO levels has been effectively
eliminated, even under severe drought conditions, as a result of upgrades beyond
primary treatment to better-than-secondary levels of waste treatment.
E. Discussion and Conclusions
In developing a methodology to evaluate the effectiveness of USEPA's
Construction Grants Program, GAO (1986b) posed four questions to evaluate the
water quality benefits obtained from upgrading municipal wastewater treatment
facilities:
Tremendous progress
has been achieved In
improving water quality,
restoring valuable
biological resources,
ami creating recreational
opportunities In all
the case study areas!
1. Did upgrading the POTW decrease the amount of pollutants dis-
charged?
2. Did water quality improve downstream from the POTW?
3. Is there a relationship between changes in a plant's effluent and
changes in stream water-quality indicators?
4. Can other reasonable explanations of a stream's water quality be
excluded?
Although many of the case studies in this report (Chapters 5 through
13) include a mix of multiple municipal and industrial wastewater dis-
charges and might not be applicable to the methodology developed by GAO
(1986b), the dramatic improvements that have been documented for
effluent loading, water quality, environmental resources, and recreational
uses clearly suggest that the answer to the questions raised by GAO
(1986b) for all nine case studies is an overwhelming "yes."
In addition to the case study questions posed by GAO, the national
policy questions raised by Congress and the public can be modified slightly
to use for evaluations of the case study waterways: Has water quality
improved as a result of public and private capital improvement expen-
ditures for water pollution control? Has the waterbody achieved the
"fishable and swimmable" goals set forth in the CWA ? Has the CWA
worked?
For all the case study waterways, tremendous progress has been made in
improving water quality, restoring valuable biological resources, and creating
thriving water-based recreational uses of the waterways that contribute to the
local economies. Although significant progress has been achieved in eliminating
noxious water pollution conditions, nutrient enrichment, and sediment contamina-
4-10
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Chapter 4: Case Study Assessments of Water Quality
tion, heavy metals and toxic organic chemicals continue to pose threats to human
health and aquatic organisms. Serious ecological problems remain to be solved for
many of the Nation's waterways, including the case study sites. The evidence is
overwhelming, however, that the national water pollution control policy decisions
of the 1972 CWA have achieved significant successes in many waterways. With
the new watershed-based strategies for managing pollutant loading from point and
nonpoint sources detailed in USEPA's Clean Water Action Plan (USEPA, 1998),
the Nation's state-local-private partnerships will continue to work to attain the
original "fishable and swimmable" goals of the 1972 CWA for all surface waters
of the United States.
4-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
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Administrators, Washington, DC.
Becker, C.D., and D.A. Neitzel, eds. 1992. Water quality in North American
river systems. Battelle Press, Columbus, OH.
Brown, B.J., and J.H. Olive. 1995. Diatom communities in the Cuyahoga River
(USA): Changes in species composition between 1974 and 1992 following
renovations in wastewater management. Ohio Journal of Science 95(3):
254-260.
Burns, N. M. 1985. Erie, the lake that survived. Rowman & Allanheld Publishers,
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Charlton, M.N. S. L'ltalien, E.S. Millard, R.W. Bachmann, J.R. Jones, R.H.
Peters, and D.M. Soballe, eds., 1995. Recent changes in Lake Erie water
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Reservoir Management 11(2): 125.
Clark, L.J., R.B. Ambrose, and R.C. Grain. 1978. A water quality modelling
study of the Delaware Estuary. Technical Report 62. USEPA Region 3,
Annapolis Field Office, Annapolis, MD.
Crawford, C.G., and D.J. Wangness. 1991. Effects of advanced wastewater
treatment on the quality of White River, Indiana. Water Resources Bulletin
27(5): 769-779.
Desbonnet, A., and V. Lee. 1991. Historical trends: Water quality and fisher-
ies in Narragansett Bay. Rhode Island Sea Grant, University of Rhode
Island, Narragansett, RI, and U.S. Department of Commerce, National
Oceanic and Atmospheric Administration, Coastal Ocean Office, National
Ocean Pollution Program, Rockville, MD.
Edmondson, W.T. 1991. The uses of ecology, Lake Washington, and beyond.
University of Washington Press, Seattle, WA.
EESI. 1995. The Houston Ship Channel: An environmental success story?
Proceedings of workshop, May 18-19, 1995, Energy & Environmental
Systems Institute, Rice University, Houston, TX. Publ. No. EESi-01.
Fitzpatrick, J.P., et al. 1991. Calibration and verification of an updated
mathematical model of the eutrophication of the Potomac estuary.
Prepared by HydroQual, Inc., for Metropolitan Washington Council of
Governments, Washington, DC.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to 1990.
U.S. Bureau of the Census, Population Division, Washington, DC.
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Frost, J. 1991. MWCC St. Paul Metro population served, plant effluent flow and
BOD5loading data, 1940 to 1990. Personal communication, Minnesota
Pollution Control Agency, St. Paul, MN.
GAO. 1986a. The nation's water: Key unanswered questions about the
quality of rivers and streams. GAO/PMED-86-6. U.S. General Accounting
Office, Program, Evaluation and Methodology Division, Washington, DC.
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Chapter 4: Case Study Assessments of Water Quality
GAO. 1986b. Water quality: An evaluation method for the Construction
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Jaworski, N.A. 1990. Retrospective study of the water quality issues of the
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
NCWQ. 1976. Public Law 92-500. Water quality analysis and environmental
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Chapter 4: Case Study Assessments of Water Quality
USEPA. 1998. Clean water action plan: Restoring and protecting America's
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Zogorski, J.S., S.F. Blanchard, R.D. Randal and F.A. Fitzpatrick. 1990. Availabil-
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
4-16
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Chapter 5
Connecticut River
Case Study
The New England Basin (Hydrologic Region 1),
covering a drainage area of 64,071 square
miles from Maine to southwestern Connecticut,
includes some of the major rivers in the continental United
States. The Connecticut River, the largest river in New
England, originates from a series of small lakes just south of
the Canadian border and flows 400 miles south over a
drainage area of 11,250 square miles through Vermont,
New Hampshire, Massachusetts, and Connecticut to Long
Island Sound (Figure 5-1). An estimated 1.1 million people
lived in the Lower Connecticut River basin in 1996.
Densely populated urban centers border the river from
Springfield, Massachusetts, downstream to Middletown,
Connecticut. The major urban centers along the river are
Holyoke-Chicopee-Springfield, Massachusetts, and Hartford,
Connecticut. A diverse mix of manufacturing, trade, finance,
agriculture, recreation, and tourism forms the economic base of the
basin.
Figure 5-2 highlights the location of the Lower Connecticut River
case study watersheds (catalog units) identified in this major river basin
as a major urban-industrial area affected by severe water pollution
problems during the 1950s and 1960s (see Table 4-2). In this chapter,
information is presented to characterize long-term trends in population,
municipal wastewater infrastructure and effluent loading of pollutants, ambient
water quality, environmental resources, and uses of the Lower Connecticut River.
Data sources include USEPA's national water quality database (STORET),
published technical literature, and unpublished technical reports ("grey" literature)
obtained from local agency sources.
Background
Although the Connecticut River has been characterized as one of the
Nation's most scenic rivers, the river was so grossly polluted in the 1960s that it
was classified as suitable only for transportation of sewage and industrial wastes.
The deplorable condition of the river discouraged development along the water-
front and adjacent shorelands over long reaches of the lower river. In recent
Connecticut
River Basin
Hydrologic
Region 1
Figure 5-1
Hydrologic Region 1 and
the Connecticut River
Basin.
5-1
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 5-2
Location map for Lower
Connecticut River Basin.
(River miles shown are
distances from Long
Island Sound.)
73
years, amazing improvements in the river's water quality have resulted in the
Lower Connecticut River's becoming a popular place for boating and recreation.
Perhaps most telling of all, the shorelines of the Connecticut River are now under
the new threat of suburban development. The historic turnaround in the quality of
the river can be correlated with the enactment of the 1972 CWA, which resulted
in the construction and upgrading of wastewater treatment plants along the length
of the river, including three major treatment plants serving the Hartford area.
Physical Setting and Hydrology
The Connecticut River forms the border between Vermont and New
Hampshire and bisects west-central Massachusetts and central Connecticut. The
topography of the Connecticut River's 11,250-square-mile watershed varies from
the rugged terrain of the White Mountains in New Hampshire and the rounded
hills and mountains in Vermont and Massachusetts to the lowlands of the flood-
plains along the river's banks in Massachusetts and Connecticut. Rising in the
semimountainous area of northern New Hampshire, the Connecticut River drops
more than half of its 2,650 feet in elevation in the first 30 miles of its course. The
river is tidally influenced from Hartford to Long Island Sound (Figure 5-2).
5-2
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Chapter 5: Connecticut River Case Study
Figure 5-3
Monthly trends of mean,
10th, and 90th percentile
streamflow for the
Connecticut River at
Thompsonville, CT (USGS
Gage 01184000), 1951-
1980.
Source: USGS, 1999.
ONDJFMAMJJAS
Long-term trends in summer streamflow from the USGS gage at
Thompsonville, Connecticut, shown in Figure 5-3, illustrate the interannual vari-
ability of discharge during the critical summer months. Seasonal flow conditions
reflect the long, cold winters and the relatively short summers characteristic of
New England. High flows are generally experienced in the spring (March-May),
corresponding to large snowmelt events (Figure 5-4). Low flows occur during the
summer months. In the past, flow regulation for hydropower production at
Holyoke Dam (Massachusetts) periodically reduced flows in the Connecticut
River to a minimum of near zero, but minimum release requirements have been
established to maintain the summer low flow at a higher level. Currently the flow
is regulated by a number of headwater lakes and reservoirs, as well as power
plants, with a combined usable capacity of 107 billion cubic feet (USGS, 1989) at
Thompsonville, Connecticut. The 7-day, 10-year low flow (7Q10) discharge at
Thompsonville is 2,200 cubic feet per second (cfs). The minimum recorded daily
discharge was 519 cfs on September 30, 1984, below the Holyoke Dam and 968
cfs on October 30, 1963, at Thompsonville, Connecticut (USGS, 1989).
40
1950
1960
1970
1980
1990
0.0
Figure 5-4
Long-term trends in mean,
10th, and 90th percentile
streamflow in summer
(July-September) for the
Connecticut River at
Thompsonville, CT (USGS
Gage 01184000).
Source: USGS, 1999.
- - • 90%ile
mean & ratio
5-3
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Progress in Water Quality: An Evaluation of the National Investment In Municipal Wastewater Treatment
Population, Water, and Land Use Trends
The population density in the Connecticut River Basin generally increases
from the north to the south. Approximately 85 percent of the river basin's resi-
dents live in Massachusetts and Connecticut. Approximately 1.1 million people
live in Connecticut municipalities adjacent to the river; the largest city, Hartford,
had a 1990 estimated population of 139,739 (CSDC, 1991).
The Connecticut River case study area includes a number of counties
identified by the Office of Management and Budget (OMB, 1999) as Metropoli-
tan Statistical Areas (MSAs) or Primary Metropolitan Statistical Areas (PMSAs).
The Hartford, Connecticut, MSA and three Connecticut counties, Fairfield,
Middlesex, and Tolland, are included in this case study. Figure 5-5 presents long-
term population trends (1940-1996) for the three counties. From 1940 to 1996, the
population in the Connecticut River case study area about doubled (Forstall, 1995;
USDOC, 1998).
The first European settlements in the Connecticut River Basin were cen-
tered around Hartford in the 1630s. During the initial 100 years of development,
the water and lands of the Connecticut River Valley provided a transportation
route to the interior, as well as food and vast quantities of timber for shelter and
fuel. Timber exploitation from 1700 to 1850 removed about three-fourths of the
basin's forest cover. Following the timber-cutting era, cleared land was used for
raising sheep and goats. The farm economy dwindled by the 1850s, and the land
began to revert back to its forested condition.
The upper basin in New Hampshire and Vermont has retained a more rural
character, although suburbanization is replacing traditional farm areas in some
locations as the small northern towns expand. The 52-mile-long tidal section of the
river in Connecticut between Long Island Sound and Hartford has traditionally
supported shipbuilding and has been used as a major route for waterborne com-
merce, mostly petroleum products. Land use in this lower basin includes large-
scale industrial and commercial development in Hartford. In the past, major
Figure 5-5
Long-term trends in
population in the Lower
Connecticut River Basin.
Sources: Forstall, 1995;
USDOC, 1998.
O.i
1940 1950 1960 1970 1980 1990 1996
5-4
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Chapter 5: Connecticut River Case Study
industries in the Hartford area included woolen mills, paper mills, and machine tool
factories. In recent decades, the economy of the lower basin has shifted from
manufacturing toward a service economy. Hartford has been deemed "the
insurance capital of the world." Beginning with the Hartford Fire Insurance
Company in 1794, insurance has become a multibillion-dollar industry.
The Connecticut River is not currently used as a public water supply in the
state of Connecticut. Most of the Connecticut River water used by agriculture in
the Connecticut River Valley is used to irrigate tobacco, vegetable crops, fruits,
and nursery stock. In 1980 approximately 11,500 acres of the 33,922 acres of
harvested cropland in Hartford County were irrigated with water from the
Connecticut River or Farmington River (a major tributary just north of Hartford)
(USACE, 1981).
Historical Water Quality Issues
Water quality problems in the Hartford area of the Connecticut River date
back to the late 1800s. In July 1914, the level of DO in the Connecticut River
near Hartford was 2 to 3 mg/L lower than levels during the late 1980s (7.4 to 7.9
mg/L in 1988) (CTDEP, 1982, 1988). Early in the river's history, the construction
of dams for hydropower had significantly exacerbated water quality problems due
to stagnation and the creation of faunal barriers. By 1872, Atlantic salmon had
been completely exterminated from the river system because of poor water
quality as well as the construction of physical barriers that prohibited the migration
of anadromous fish (Center for Environment and Man, 1975).
In 1955, the New England Interstate Water Pollution Control Commission
classified the Connecticut River from Holyoke Dam in Massachusetts to
Middletown, Connecticut, as a Class D waterway suitable for "transportation of
sewage and industrial wastes without nuisance and for power, navigation, and
certain industrial uses" (Kittrell, 1963). Severe water pollution problems in this
reach of the Connecticut River have resulted from two sources, industrial effluent
and municipal sewage disposal. One of the major industries responsible for
degradation of water quality has been paper mills. Before the late 1970s, paper
mills in the Massachusetts segment of the river discharged effluent with high
concentrations of BOD5 and suspended solids into the river (Center for Environ-
ment and Man, 1975). Downstream of the paper mills in Holyoke, Massachusetts,
it was reported that the river flowed different colors depending on the dye lot
used at the paper mill that day.
In 1963 it was reported that in the stretch of river from central Massachu-
setts to south of Hartford, Connecticut, 9 of the 22 jurisdictions responsible for
discharge of sewage provided no wastewater treatment. Twelve of the 22
provided only primary treatment, and 1 provided secondary treatment (Kittrell,
1963). Large discharges of municipal and industrial wastes caused a steady
depletion of DO downstream of the Holyoke Dam in Massachusetts. Minimum
DO levels reached nearly zero during a low flow survey in 1966, and DO levels
of less than 2 mg/L were recorded in 1971. Connecticut River data collected in
the summer of 1971 documented other forms of pollution with a minimum density
of coliform bacteria of 75,000 colonies/100 mL and a maximum of over 1 million
colonies/100 mL (Center for Environment and Man, 1975).
5-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Legislative and Regulatory History
On the basis of reports indicating that pollution in this reach of the Connecti-
cut River was endangering the health and welfare of persons in Connecticut, the
Secretary of Health, Education and Welfare convened a conference under
Section 8 of the Federal Water Pollution Control Act (33 U.S.C. 466g et seq.) in
1963 to investigate the pollution of the Connecticut River in Massachusetts and
Connecticut. This conference documented the appalling water quality of the
Connecticut River and initiated strategies to begin to clean up the river (Kittrell,
1963). By the early 1960s, the steadily increasing public concern regarding water
pollution issues resulted in organized planning for implementation of primary and
secondary wastewater treatment in several municipalities including Hartford,
Connecticut.
Since 1963 USEPA's Construction Grants Program has been responsible for
elimination of vast amounts of untreated or partially treated wastewater entering
the Connecticut River. The process of reducing the loadings and substantially
improving the quality of the Connecticut River was significantly influenced by the
1972 CWA. Subsequent to the enactment of this legislation, 125 new or upgraded
treatment plants were constructed along the Connecticut River at a cost of nearly
$900 million (Conniff, 1990). From 1972 through 1984 eligible projects were
funded 75 percent by federal grants, 15 percent by state grants, and 10 percent by
local financing; prior to 1972 the federal share was 55 percent (CTDEP, 1982).
Three secondary wastewater treatment plants in the Hartford area (Hartford,
East Hartford, and Rocky Hill) were completed by the mid-1970s (Gilbert, 1991).
One of the major problems still facing this important New England water-
way, however, is combined sewer overflows (CSOs). Overflows during storm
events can still cause discharge of untreated sewage into the Connecticut River
between Springfield, Massachusetts, and Middletown, Connecticut. CSO prob-
lems are the principal reason the Connecticut River does not consistently meet the
Class B fishable/swimmable standard for fecal coliform in northern Connecticut
(above Middletown) (Mauger, 1991).
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
As a result of implementation of municipal and industrial wastewater
treatment in the Connecticut River Basin, total pollutant loading has decreased
substantially in the past 30 to 40 years. The approximate total population served
by the 22 sewer systems in the Connecticut and Massachusetts portions of the
river basin in 1963 was 734,265 people; of these, 282,590 (38 percent) resided in
East Hartford and Hartford, Connecticut (Kittrell, 1963). In 1990 the sewered
population of the greater Hartford metropolitan area was 366,574, served by the
Hartford, East Hartford, and Rocky Hill facilities. The largest of these, the
Hartford water pollution control plant, currently has secondary treatment with
upgrades from 60 mgd to 80 mgd by 1993 (Gilbert, 1991).
5-6
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Chapter 5: Connecticut River Case Study
Since implementation of the 1972 CWA, substantial reductions in point
source loads of oxidizable materials have been achieved as a result of technology-
and water quality-based effluent controls on municipal and industrial dischargers
in the Connecticut River watershed. Nonpoint source runoff, driven by the land
uses and hydrologic characteristics of the watershed, also contributes a pollutant
load to the Connecticut River that must be considered in a complete evaluation of
the impact of regulatory policy and controls on long-term water quality trends. To
evaluate the relative significance of point and nonpoint source pollutant loads,
inventories of NPDES point source dischargers, land uses, and land use-depen-
dent export coefficients (Bondelid et al., 1999) have been used to estimate catalog
unit-based point (municipal, industrial, CSOs) source and nonpoint (rural, urban1)
source loads of BOD5 for contemporary (ca. 1995) conditions in the case study
area (Figure 5-6). Municipal facilities contribute 42 percent (10.5 metric tons/day)
of the total estimated BOD5 load, while industrial dischargers account for 10
percent (2.4 metric tons/day) of the total BOD5 load. Nonpoint sources of BOD5
account for a total of 47 percent, with rural runoff contributing 13 percent (3.3
metric tons/day) and urban land uses accounting for 34 percent (8.5 metric tons/
day) of the total load (Figure 5-6).
Oxygen depletion and high BOD5 levels historically have been documented
downstream from the major wastewater discharges in the Massachusetts and
Connecticut segments of the river. Prior to upgrading publicly owned treatment
works (POTWs) in the southern Massachusetts sections of the river, water
quality monitoring data near the Connecticut/Massachusetts border documented
that DO concentrations in the river violated the Massachusetts state standard (5
mg/L for non-low-flow periods) 22 percent of the days recorded in the early
1970s (June-October) (Isaac, 1991). Minimum recorded DO levels reached
nearly 0 mg/L in a 1966 survey and less than 2.0 mg/L in 1971 (NCWQ, 1975) in
Massachusetts. After POTW upgrades, by 1974 violations had dropped to only 6
percent of the days of record with DO less than 5 mg/L (Isaac, 1991) (Figure 5-
7).
RURAL-NPS
URBAN-NPS
CSO
IND.MAJ+MIN
MUNICIPAL
Figure 5-6
Comparison of point and
nonpoint source loads of
BOD5(ca. 1995) for the
Lower Connecticut River
Basin.
Source: Bondelid et al.,
1999.
5 10
BODS Load (metric tons/day)
15
1 For purposes of this comparison, urban stormwater runoff includes areas both outside (termed
"nonpoint sources") and within (meeting the legal definition of a point source in section 502(14)
of the CWA) the NPDES stormwater permit program.
5-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 5-7
Trends in violations of DO
standard (DO < 5 mg/L) in
summer (July-September)
for the Connecticut River
before (1969-1973) and
after (1974-1980) con-
struction and upgrade of
municipal wastewater
treatment facilities at
Agwam, MA.
Source: Isaac, 1991.
I
&
75-
50-
25-
oH
6
27
:<
I
I
wi
1
i*
K)
=X
sS
^
%
12
1969 1970 1971 1972 1973
Before (1969-73)
0
1974
0
23
1
0
15
1975 1976 1977' 1978 1979 1980
After (1974-80)
: i
r tn
V
E a
1 1
ys Violatio
Q
^p
o^
rO%
Days of Record
% Days of Violation
The average summer DO concentrations in the Lower Connecticut River in
northern Connecticut (Hartford to Windsor) have also improved steadily since the
mid-1960s (Figure 5-8). Corresponding to the increase in DO shown has been a
progressive decline in ambient BOD5 that reflects upgrades to Hartford area
wastewater treatment facilities (Figure 5-9). Since the early 1970s, the average
summer (July to September) DO levels in the Lower Connecticut River from
Haddam to Middletown have remained above 7 mg/L (Figure 5-10). In a Septem-
ber 1988 intensive survey of water quality in the Lower Connecticut River, the
DO concentrations ranged from 7.3 to 7.9 mg/L for all 10 stations sampled from
the Massachusetts/Connecticut border to near the mouth of the river (CTDEP,
1988). The improvement in water quality in the Lower Connecticut River as a
result of the significant reductions in oxidizable pollutant loading over the past 30
years has been substantial.
Figure 5-8
Long-term trends in DO for
the Lower Connecticut
River from Hartford to
Windsor, CT (RF1-
01080205029, miles 50.3-
57.3).
Source: USEPA (STORET).
Mean Mm Max
1940 1950 1960 1970 1980
Hartford-Windsor CT (Mile 50.3-57.3)
1990
5-8
-------
Chapter 5: Connecticut River Case Study
1940
1950
1960 1970 1980
Windsor-Rocky Hill CT
1990
Mean Mm Max
Figure 5-9
Long-term trends in BOD5
in the Lower Connecticut
River from Windsor to
Rocky Hill, CT.
Source: Reimold, 1991.
Figure 5-10
Long-term trends in DO
for the Lower Connecticut
River from Haddam to
Middletown, CT. (RF1-
01080205021, miles 16.3-
21.6).
Source: USEPA (STORET).
W
Impacts of Wastewater Treatment:
Recreation and Living Resources Trends
Information on biotic populations in the Connecticut River is scarce for most
of the period previous to 1975 (Center for the Environment and Man, Inc., 1975).
The precolonial salmon population was very large and supplied Native Americans
and, later, early colonists with an abundant food supply. A long absence of
Atlantic salmon in the river was noted between 1874 and the late 1970s. An
Atlantic salmon caught in 1977 was the first documented occurrence of the fish in
the river since 1874 (USEPA, 1980).
The absence of salmon can be attributed partially to dam construction,
which prevented the fish from migrating upstream to spawn, and partially to water
pollution. The first dam across the river was constructed in 1798 at Turners Falls,
Massachusetts (Jobin, 1998). Fish ladders were built around dams when people
began to understand that the dams prevented migration, yet 200,000 hatchery
salmon placed in the river between 1968 and the early 1970s failed to return to
the river to spawn, presumably because of the poor water quality (USEPA, 1980).
Efforts to clean up the river began after passage of the 1972 CWA, and the return
of the salmon in the late 1970s can be attributed to improved water quality.
Another anadromous fish species historically important to commercial and
recreational fishing on the Connecticut River is the American shad. Shad had a
precarious existence in the river before 1975 (Center for Environment and Man,
5-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 5-11
Long-term trends of shad
relative abundance for the
Lower Connecticut River.
Source: Savoy and Shake,
1991.
1960
1965
1970
1975
1980
1985
1990
Inc., 1975), but their population increased afterward (Figure 5-11). The estimated
mean population for the years 1975-1989 was 841,265 (Savoy, 1991). The 1990
estimated population was 654,885, lower than the previous 14-year mean but
considered by the Connecticut Department of Environmental Protection
(CTDEP) to be stable.
Other indices lead to the conclusion that the shad population is faring well in
the Connecticut River. The 1990 commercial catch of shad in the river
(x = 9687, adjusted for angler effort) was nearly twice the 1989 catch (x = 5243)
and reversed a general declining trend that lasted from 1986 to 1989 (Savoy,
1991). Similarly, juvenile shad had strong relative abundances from 1987 to 1990
(Figure 5-11), indicating good reproductive success (Savoy, 1991). Juvenile fish
are generally less tolerant than adults of low DO concentrations, so an improve-
ment in reproductive success is a good indicator of improving water quality.
Summary and Conclusions
The federal, state, and local funding for construction of municipal wastewa-
ter treatment facilities in the Connecticut River Basin has led to significant
improvement in water quality since the 1960s. A river basin that during the early
1970s was considered a flowing sewer is now a popular recreational area. One
measure of the improvement in the fishable/swimmable quality of the river is
documented by the U.S. Fish and Wildlife Service. Dramatic improvements in
water quality, along with the installation offish ladders to eliminate physical
barriers to migration, have resulted in the successful return of Atlantic salmon to
the Connecticut River.
Concentrations of total nitrogen and total phosphorus in the Connecticut
River case study area since the CWA have followed the national trends—
phosphorus and ammonia-N have decreased with associated increases in nitrate-
N and total-nitrogen, indicating that improved wastewater treatment has improved
water quality (Garabedian et al., 1998). In its report Water Quality in the Con-
necticut, Housatonic, and Thames River Basins, Connecticut, Massachusetts,
New Hampshire, New York, and Vermont, 1992-95, the U.S. Geological Survey
concluded that increasing nitrate concentrations may contribute to eutrophication
in Long Island Sound.
5-10
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Chapter 5: Connecticut River Case Study
References
Bondelid, T., C. Griffiths, and G. Van Houten. 1999. A national water pollution
control assessment model. Draft technical report prepared for U.S. Envi-
ronmental Protection Agency, Office of Science and Technology, Washing-
ton, DC, by Research Triangle Institute, Durham, NC.
Center for Environment and Man. 1975. Environmental impact assessment.
Water quality analysis. Connecticut River. Prepared for the National
Commission on Water Quality, Washington, DC. Report No. NCWQ 75/51.
National Technical Information Service No. PB-250 924. April.
Conniff, R. 1990. The transformation of a river from sewer to suburbs in 20
years. Smithsonian 21(l):71-84.
CSDC. 1991. 1990 Census population by municipality. State of Connecticut
Office of Policy and Management, Connecticut State Data Center, Hartford,
CT.
CTDEP. 1982. The Connecticut River—worth the cost! Connecticut Depart-
ment of Environmental Protection, Water Compliance Division.
CTDEP. 1988. Connecticut River intensive survey, September 7-8, 1988.
Connecticut Department of Environmental Protection, Water Compliance
Division.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to 1990.
U.S. Bureau of the Census, Population Division, Washington, DC. .
Garabedian, S.P., J.F. Coles, S.J. Grady, E.C.T. Trench, and M.J. Zimmerman.
1998. Water quality in the Connecticut, Housatonic, and Thames River
Basins, Connecticut, Massachusetts, New Hampshire, New York, and
Vermont, 1992-1995. U.S. Geological Survey Circular 1155. U.S. Geologi-
cal Survey, Reston, VA.
Gilbert, P. 1991. Metropolitan District Commission, Hartford, CT. Personal
communication.
Isaac, R.A. 1991. POTW improvements raise water quality. Water Environ-
ment and Technology 3(6):69-72.
Jobin, W.R. 1998. Sustainable management for dams and waters. CRC
Press, Boca Raton, FL.
Kittrell, F.W. 1963. Report to the conference in the matter of pollution of the
interstate waters of the Connecticut River, Massachusetts-Connecticut.
U.S. Department of Health, Education and Welfare. December.
Mauger, A. 1991. Water Compliance Division, State of Connecticut Department
of Environmental Protection, Hartford, CT. Personal communication.
NCWQ. 1975. Environmental impact assessment, water quality analysis -
Connecticut River. National Commission on Water Quality, Washington,
DC.
OMB. 1999. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
5-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Reimold, R. 1991. Metcalf & Eddy, Inc., Boston, MA. Personal communication.
Savoy, T. 1991. Sturgeon status in Connecticut waters. Completion Report.
Project No. AFC-18. State of Connecticut, Department of Environmental
Protection, Division of Marine Fisheries, Waterford, CT. June.
Savoy, T., and D. Shake. 1991. Population dynamics studies of American
shad, Aloosa sapidissima in the Connecticut River. U.S. Department of
Commerce, National Oceanic and Atmospheric Administration, National
Marine Fisheries Service. June 30.
USAGE. 1981. Water resources development in Connecticut 1981. U.S.
Army Corps of Engineers, New England Division, Waltham, MA.
USDOC. 1998. Census of Population and Housing. Prepared by U.S.
Department of Commerce, Economics and Statistics Administration, Bureau
of the Census - Population Division, Washington, DC.
USEPA. 1980. National accomplishments in pollution control: 1970-1980.
Some case histories. The Connecticut River: salmon are caught again.
U.S. Environmental Protection Agency, Office of Planning and Evaluation,
Program Evaluation Division. December.
USEPA (STORE!). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
Watersheds, Washington, DC.
USGS. 1989. Water resources data, Connecticut water year 1988. USGS
Water-Data Report CT-88-1. U.S. Geological Survey, Hartford, CT.
USGS. 1999. Streamflow data downloaded from the U.S. Geological Survey's
National Water Information System (NWIS)-W Data retrieval for historical
streamflow daily values, .
5-12
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Chapter 6
Hudson-Raritan
Estuary Case
Study
The Mid-Atlantic Basin (Hydrologic Region 2),
covering a drainage area of 111,417 square
miles, includes some of the major rivers in
the continental United States. Figure 6-1 highlights
the location of the basin and the Hudson-Raritan
Estuary, the case study watershed profiled in this
chapter.
With a length of 306 miles and a drainage
area of 13,370 square miles, the Hudson River
ranks 71st among the 135 U.S. rivers that are more
than 100 miles in length. On the basis of mean annual
discharge (1941-1970), the Hudson ranks 26th (19,500 cfs) of
large rivers in the United States (Iseri and Langbein, 1974). Urban-
industrial areas in the watershed caused severe water pollution
problems during the 1950s and 1960s (see Table 4-2). This chapter
presents long-term trends in population, municipal wastewater
infrastructure and effluent loading of pollutants, ambient water quality,
environmental resources, and uses of the Hudson-Raritan Estuary. Data
sources include USEPA's national water quality database (STORET), published
technical literature, and unpublished technical reports ("grey" literature) obtained
from local agency sources.
Hudson-
Raritan
Estuary
Background
Figure 6-1
Hydrologic Region 2 and
Hudson-Raritan estuary
watershed.
The Hudson-Raritan Estuary, with its rich and diverse populations of birds,
fish, and shellfish, is unmatched in terms of the historical abundance of its natural
resources. New York City, in fact, owes its existence as a major urban center to
the bounty of the estuary (Trust for Public Lands, 1990). The estuarine and
6-1
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
coastal waters around New York City support significant fish and wildlife re-
sources (Sullivan, 1991). For example, the extensive wetland systems along the
Arthur Kill on northwest Staten Island, adjacent to one of the most industrialized
corridors in the northeastern United States, has recently been colonized by several
species of herons, egrets, and ibises (Trust for Public Lands, 1990). Current heron
populations represent up to 25 percent of all nesting wading birds along the coast
from Cape May, New Jersey, to the Rhode Island line (HEP, 1996). Today,
despite mounting pressures for industrial and residential development, there is a
growing awareness of the estuary's unique ecological function and a new appre-
ciation of its almost limitless potential as a recreational, cultural, and aesthetic
resource (Trust for Public Lands, 1990).
For more than 300 years, New York Harbor and the New York metropolitan
region have been a focal point of urban development, transportation, manufactur-
ing, and commerce. New York City has been characterized by tremendous
population increases and economic growth and has traditionally been a major
Harbor. As a large estuary with vast wetlands and marsh areas, New York
harbor offered an abundance of natural resources that supported a commercially
important shellfish industry until its decline in the early 1900s. With a relatively
deep protected estuary that was ideal for navigation, the harbor developed as a
key shipping and transportation link for commerce and passenger traffic between
the inland states and Europe.
Physical Setting and Hydrology
New York Harbor is formed by a network of interconnected tidal water-
ways along the shores of New York and northern New Jersey; it is bounded by
the Hudson River to the north, Long Island Sound to the east, and the Atlantic
Ocean to the south (Figure 6-2). Freshwater tributaries discharging into the
estuary drain an area of 16,290 square miles and contribute approximately 81
percent of the total freshwater inflow to the harbor. The remainder of the fresh-
water input is contributed by wastewater (15 percent); urban runoff (4 percent);
CSOs (1 percent); and industrial discharges, landfill leachate, and precipitation
(0.5 percent) (Brosnan and O'Shea, 1996a). Fresh water is also imported into the
New York City water supply system from the combined watershed areas of the
Delaware and Catskills mountains with eventual discharge via the wastewater
drainage system into the harbor.
Seasonal and interannual variation of streamflow of the Hudson River
recorded at Green Island, New York, near Troy (USGS gage 01358000) is
characterized by high flow during March through May, with the monthly mean
peak flow of 32,719 cfs observed in April (Figures 6-3 and 6-4). Fligh spring
flows result from spring snowmelt and runoff over the mountainous drainage
basin. Low-flow conditions occur during July through September, with the mean
monthly minimum of 5,797 cfs observed during August. In dramatic contrast to
the long-term (1951-80) summer (July-September) mean of 6,396 cfs, during the
extreme drought conditions of 1962-1966, mean summer flow was only 49 to 70
percent of the long-term mean summer flow. The driest conditions occurred
during the summer of 1964 with a mean flow of 3,104 cfs and a minimum flow of
only 1,010 cfs (Bowman and Wunderlich, 1977; O'Connor et al., 1977). Inspec-
6-2
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Chapter 6: Hudson-Raritan Estuary Case Study
74°30'
73°45'
40°30'~
14 Miles
40°30'
Figure 6-2
Location map of the
Hudson-Raritan Estuary.
(River miles shown are
distances from Sandy
Hook-Rockaway transect
of Atlantic Ocean.)
74°30'
73°45'
Figure 6-3
Monthly trends of mean,
10th, and 90th percentile
streamflow for the Hudson
River at Green Island, NY
(USGS Gage 01358000),
1951-1980.
Source: USGS, 1999.
ONDJ FMAMJ JAS
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 6-4
Long-term trends in mean,
10th, and 90th percentile
streamflow in summer
(July-September) for the
Hudson River at Green
Island, NY (USGS Gage
01358000).
Source: USGS, 1999.
25
5- c
?940 1950 1960
1970
1980
1990
90%ile
mean & ratio
tion of the long-term trend data (1947-1995) for summer streamflow clearly
shows the persistent drought conditions of the 1960s, as well as the high-flow
conditions recorded a decade later (Figure 6-4).
Population, Water, and Land Use Trends
In 1628 New York City was a small village of 270 settlers; today it is an
urban metropolis of 16 million (Figure 6-5). The physical environment of the New
York region has contributed greatly to its enormous growth and economic devel-
opment. The natural port of the harbor has made commerce and shipping a major
component of the economy since the colonial era. The Watchung and Ramapo
mountains, west and northwest of the city, also focused growth around the harbor
by constraining transportation routes and land development patterns. In 1810 New
York emerged as the largest city in the new nation, surpassing Boston and
Figure 6-5
Long-term trends in
population for the New
York-Northern New Jersey-
Long Island CMSA
counties for the Hudson-
Rantan Estuary
metropolitan region.
Source: Forstall, 1995;
USDOC, 1998.
1940 1950 1960 1970 1980 1990 1996
6-4
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Chapter 6: Hudson-Raritan Estuary Case Study
Philadelphia. New transportation routes—the Erie Canal in 1825 and railroad
connections between New York and Philadelphia in 1839—strengthened the city's
link to Europe and the Nation's interior. During the massive European immigration
period of the mid-1800s to the early 1900s, immigrants to the United States
passed through Ellis Island in New York Harbor, a main port of entry. Many
chose to remain and contribute to the growth of the city.
The Hudson-Raritan Estuary case study area includes a number of counties
identified by the Office of Management and Budget (OMB) as Metropolitan
Statistical Areas (MSAs) or Primary Metropolitan Statistical Areas (PMSAs).
Table 6-1 lists the MSA and counties included in this case study. Figure 6-5
presents long-term population trends (1940-1996) for the counties listed in Table
6-1. From 1940 to 1996, the population in the Hudson-Raritan Estuary case study
area increased by 34 percent from 12.6 million in 1940 to 17,0 million in 1996
(Forstall, 1995;USDOC, 1998).
Because of the proximity to shipping and other transportation routes, manu-
facturing and industrial development evolved as a major component of the
region's industrial economy and a major contributor to the environmental decline
of the area's once bountiful wetlands. New Jersey, the most densely populated
state in the Nation, is second only to California in industrialization, and most of the
industrial activity of New Jersey is centered around New York Harbor. Within
New York City, economic growth has depended on manufacturing, services,
world trade, and the city's position as a national and international center for banks,
finance, culture, and the arts. Since the turn of the century, and particularly since
the development of the automobile and highways, progressive suburban develop-
ment radiating from the city has transformed the once agricultural region into a
densely populated metropolitan area. At a distance of about 60 miles from New
York City, however, farmland, rural lands, and low-density suburban towns still
characterize the outer fringes of the metropolitan region.
Table 6-1. Metropolitan Statistical Area (MSA) counties in the Hudson-Raritan
Estuary case study. Source: OMB, 1999.
Fairfield County, CT
Litchfield County, CT
New Haven County, CT
Bergen County, NJ
Essex County, NJ
Hudson County, NJ
Hunterdon County, NJ
Middlesex County, NJ
Monmouth County, NJ
Morris County, NJ
Ocean County, NJ
Passaic County, NJ
Somerset County, NJ
Sussex County, NJ
Union County, NJ
Warren County, NJ
Bronx County, NY
Dutchess County, NY
Kings County, NY
New York County, NY
Orange County, NY
Putnam County, NY
Queens County, NY
Richmond County, NY
Rockland County, NY
Westchester County, NY
Pike County, PA
6-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Despite intense development and the loss of wildlife habitat due to wetland
conversion, the New York/New Jersey Harbor and the New York Bight do
contain significant fish and wildlife resources. Water uses of the Hudson River
and New York Harbor include public water supply of the freshwater river up-
stream of Poughkeepsie, New York, municipal and industrial wastewater disposal,
commercial shipping and navigation, recreational boating, swimming, and commer-
cial and recreational fishing. Although commercial fishing was once a significant
component of the New York-New Jersey regional economy, the abundance of
commercially important fish and shellfish has declined considerably during the
past century. The loss of once abundant fishery resources has been attributed to
disease, overfishing, loss of habitat, and poor water quality conditions. Despite the
significant reductions in fishery resources, commercial fishing of more than 60
species of seafood contributed approximately $500 million to the regional econo-
mies of New York and New Jersey during the mid-1990s (Schwartz and Porter,
1994). Recreational fishing in the New York Harbor, Long Island Sound, and New
York Bight is also quite important, accounting for more than $ 1 billion annually in
economic activity for New York and New Jersey during the mid-1990s (Schwartz
and Porter, 1994).
Historical Water Quality Issues
Waste disposal issues in New York did not emerge only recently. Contempo-
rary residents of the New York metropolitan area would be surprised to learn that
public policy debates related to waste disposal and water pollution issues began
only a few decades after colonial settlers arrived in the New World. The early
settlers' practice of simply dumping pails of sewage and other refuse into the
harbor became such a problem that in 1680 the Governor ordered that a common
sewer be constructed in Lower Manhattan. In 1683 the Common Council decreed
"that none doe cast any dung, drought, dyrte or any other thing to fill up or
annoy the mould or Dock or the neighborhood near the same, under the
penalty of twenty skill" (Gross, 1976). Construction of a sewer and wastewater
collection system in New York City began in 1696, with many sewers in lower
and central Manhattan constructed two centuries later between 1830 and 1870
(O'Conner, 1990). Pollution problems existed, however, in both New York City
and Newark, New Jersey, because the harbor received untreated wastewater
from the sewers.
In 1868 unsanitary conditions were described as "poisoning the water and
contaminating the air" (Suszkowski, 1990). During the 1920s the overpowering
stench of hydrogen sulfide from polluted water in the Passaic River near Newark,
New Jersey, forced excursion boat passengers to seek refuge in the cabins
(Cleary, 1978). During that period, all the regional New York and New Jersey
communities discharged raw sewage into the harbor "to conduct by the cheap-
est route to the nearest waterway, giving no thought whatever to its effect on
the waterway and on adjacent waters" (Franz, 1982). In the 1920s New York
City discharged approximately 600 mgd of raw sewage into the harbor (Brosnan
andO'Shea, 1996a).
The earliest water pollution surveys of New York Harbor began with the
formation of the Metropolitan Sewerage Commission of New York in 1906. In a
1910 report on conditions of the harbor, the Commission stated that "Bathing in
6-6
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Chapter 6: Hudson-Raritan Estuary Case Study
New York Harbor above the Narrows is dangerous to health, and the oyster
industry must soon be entirely given up." The Commission further noted that a
number of tributaries and tidal channels in the harbor "have become little else
than open sewers. Innumerable local nuisances exist along the waterfront of
New York and New Jersey where the sewage of the cities located about the
harbor is discharged . . . ." Finally, the commission concluded that "the water
which flows in the main channels of the harbor . . . is more polluted than
considerations of public health and welfare should allow'" (Suszkowski,
1990). As with many other urban areas around the turn of the century, develop-
ment of a combined drainage network for storm water and sewage collection
evolved to address public health problems resulting from inadequate methods of
waste disposal that created a nuisance in the streets and contaminated ground
water supplies (Fuhrman, 1984).
With vast marshlands, embayments, and interconnecting tidal channels, New
York Harbor once supported abundant populations offish, shorebirds, and shellfish
that were important local food resources and essential to certain commercial
activities. The progressive decline of the once thriving oyster industry provides an
important ecological indicator of the trends in environmental quality of New York
Harbor. Commercially important oyster beds were harvested during the 1800s in
Raritan Bay, the Kill Van Kull, Jamaica Bay, and Newark Bay, and in the
Shrewsbury River. By the turn of the century, waste disposal from industries and
towns began to seriously affect the survival of seed beds. In addition to industrial
waste and sewage discharges, dredging and disposal of dredge spoils, illegal
dumping of cellar dirt, street sweepings, and refuse all contributed to the demise
of this once valuable estuarine resource.
Although a century of pollution, disruption of habitat, and mismanagement of
seed beds all contributed to the decline of oyster abundance, bacterial contamina-
tion from raw sewage disposal was the catalyst for the death of the commercial
oyster industry. As early as 1904, typhoid cases were linked to consumption of
contaminated oysters. By 1915, 80 percent of the city's 150 typhoid cases were
attributed to contaminated oysters harvested from the harbor. In 1924 and 1925
another major outbreak occurred, even though many of the beds had been closed
in 1921 because of public health reasons (Franz, 1982). More than three decades
later, consumption of sewage-contaminated hard clams from Raritan Bay again
resulted in serious public health problems with an outbreak of infectious hepatitis
in 1961.
Oysters, however, were not the only natural resource to suffer serious
depletion of once-abundant stocks. In the closing decades of the 19th century,
pollution and habitat destruction had begun to seriously degrade water quality and
affect the abundance of marine resources. A century-long record of commercial
fishery landings for New York and New Jersey clearly documents the adverse
impact of water pollution and habitat destruction on the rich natural resources of
the estuary (Esser, 1982). Combined landings of important estuarine and anadro-
mous species such as shad, alewifc, striped bass, sturgeon, American oyster, hard
clam, and bay scallop have declined 90 percent over the past century from 58
million pounds in 1887 to 6.6 million pounds in 1996(McHughetal., 1990;
Wiseman, 1997) (Figure 6-6). In interpreting this long-term trend, it is important to
realize that even a century ago resource abundance was already considered
depleted in comparison to reports of abundance recorded through 1850. Contem-
6-7
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 6-6
Long-term trend of
commercial landings of
major anadromous and
estuarine species in New
York Harbor.
Source: McHugh et al,,
1990; Wiseman, 1997.
75
c
o
§,
"5
50-
* 25-
o
o
1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
-t-
-t-
-t-
-t-
-t-
porary degradation of the resources of the estuary, marked by successive anthro-
pogenic assaults and incremental improvements in wastewater treatment, is
believed to have begun as early as 1870 (Carriker et al., 1982).
The connection between raw sewage disposal and the decline of the oyster
beds in the lower Hudson River eventually led to the creation of the New York
Bay Pollution Commission in 1903 and the Metropolitan Sewerage Commission in
1906 (Franz, 1982). Routine water pollution surveys have been conducted in New
York Harbor since 1909. This unique data set represents the longest historical
record of water quality in the Nation and one of the longest historical records in
the world (O'Connor, 1990; Bronsand and O'Shea, 1996a). Historically, water
quality problems in the harbor have included severe oxygen depletion and closure
of shellfish beds and recreational beaches due to bacterial contamination. More
recently, nutrient enrichment, algal blooms, heavy metals, sediment contamination,
and bioaccumulation of toxics such as PCBs in striped bass (Faber, 1992;
Thomann et al., 1991) and bald eagles (Revkin, 1997) have also become areas of
concern.
By the 1920s summer oxygen within much of the harbor had deteriorated to
critical levels of less than 20 percent saturation (Brosnan and O'Shea, 1996a).
Along with oyster industry records, long-term DO records document a progres-
sive decline in the environmental quality of the harbor from 1910 through about
1930 as a result of increased population growth and raw sewage loading to the
harbor (Brosnan and O'Shea, 1996a; Wolman, 1971). Following a period of very
low oxygen saturation from about 1920 through 1950, the subsequent increasing
trend generally corresponds chronologically to incremental improvements in
construction and upgrades of sewage treatment plants beginning in 1938 (Brosnan
and O'Shea, 1996a).
With the completion of New York City's last two sewage treatment plants in
1986-1987, one of the major remaining water pollution problems in the harbor
results from combined sewer overflows that discharge raw sewage and street
debris. Following storm overflows, high bacteria levels require the closing of
shellfish beds and bathing beaches. Although an aggressive industrial pretreat-
ment program reduced the total industrial metal contribution to New York City
plants from 3,000 Ib/day in 1974 to 227 Ib/day in 1991 (Brosnan et al., 1994), early
6-8
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Chapter 6: Hudson-Raritan Estuary Case Study
ambient data still suggested violations of state water quality ;
in many locations of the harbor. More recent investigations c
auspices of the NY/NJ Harbor Estuary Program (HEP) indie
lower metal concentrations, with harborwide exceedances fo
cury. Current monitoring and modeling efforts have greatly r
waters suspected to be in violation of standards for nickel, le
(Stubin, 1997).
Additional toxic chemical problems in the harbor are as
contamination of sediments and striped bass and other marine orga:
from the discharge from two General Electric plants upstrear
1940s through the mid-1970s (Thomann et al., 1991). With a c
ban imposed because of PCB contamination (Faber, 1992), the
population is thriving to the extent that the abundance of contaminated
caught in nets and then returned to the estuary is actually ere
hardship for the commercial shad fishery (Suszkowski, 1990
of-the-art monitoring and analysis technologies have detecte<
trations of PCBs in regional sewage treatment plant effluent;
down programs, again initiated under the auspices of HEP, se
sources of these PCB contributions to the municipal waste stream
:andards for metals
>nducted under the
ited significantly
nd only for mer-
duced the extent of
d, and copper
ociated with PCB
misms resulting
i of Albany from the
ommercial fishing
striped bass
bass
ting an economic
. More recent state-
trace level concen-
, Current track-
jk to determine the
Legislative and Regulatory History
Responding to the increasingly polluted conditions of th
New York State legislature directed the city of New York to :
estuary, in 1906 the
orm the Metropoli-
tan Sewerage Commission of New York. This commission was charged with the
dual tasks of investigating the extent of water pollution in the
ing a plan to improve city sanitary conditions. In addition to re
larbor and formulat-
commendations for
upgrades of waste treatment, which eventually were implemented beginning in the
1930s, the Commission also recommended that outfalls be relocated from
nearshore to a central diffuser in the Lower Bay. A central diffuser system,
however, was never adopted (Suszkowski, 1990).
Construction of primary wastewater treatment plants in
estuary began with Passaic Valley, New Jersey, coming on lin
by Yonkers, New York, in 1933. During the construction of tl
plants in the 1930s and 1940s in New York City, the New Yo
of Public Works maintained an active role in research and de
treatment processes, particularly in the area of biological wa;
Although the federal government's primary role was to provi
through the Public Health Service, the Roosevelt Administrati
federal public works funding for sewage treatment plant con;
the Hudson-Raritan
in 1924 followed
e first treatment
k City Department
^elopment of waste
te treatment.
e technical advice
n did provide
truction as a relief
program during the Great Depression (O'Connor, 1990). Because of the regional
nature of water pollution problems, New York, New Jersey, and Connecticut
established the Interstate Sanitation Commission (ISC) to develop water quality
standards and to report on progress in water pollution control in the harbor.
Following the passage of the Federal Water Pollution Control Act and
amendments in 1948 and 1956, the federal government began to assume a larger
role in funding for water pollution control. Beginning in 1956 and continuing on a
much larger scale with the 1972 CWA, the Construction Grants Program has
provided funding for construction of municipal wastewater treatment plants (see
6-9
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Chapter 2). Following the 1965 Federal Water Pollution Control Act, federal
funding through the Public Health Service and the Federal Water Pollution Control
Administration was also available to provide technical assistance in monitoring
and analysis to investigate water quality management issues (FWPCA, 1965,
1969). Under the 1972 CWA, areawide 208 studies were conducted to evaluate
regional water quality management solutions related to waste treatment facility
needs (Hazen and Sawyer, 1978; O'Connor and Mueller, 1984). Authorization for
New York City Department of Environmental Protection (NYCDEP) to oversee
its own industrial pretreatment program for corrosion control in 1987 has led to
significant reductions in heavy metal loadings (Brosnan et al., 1994). A citywide
CSO Abatement Program is under way to comply with USEPA's national CSO
strategy. New York City has allocated $1.5 billion for construction of CSO
abatement facilities over the next 10 years and is proceeding with water quality
studies and facility planning. In the meantime, the city implemented the "Nine
Minimum Controls" issued by USEPA as part of the 1994 National CSO Control
Policy, with significant improvements in water quality conditions (Brosnan and
Heckler, 1996; Heckler et al., 1998). Since enactment of the 1965 amendments to
the Federal Water Pollution Control Act, $7.5 billion has been invested by federal,
state, and local governments to upgrade 11 of 12 water pollution control plants and
to construct and upgrade the North River and Red Hook plants (Adamski and
Deur, 1996).
With limited open land area, sludge disposal has always been a major
problem for the New York-New Jersey region. In 1924 New York City began
routine ocean disposal of sewage sludge at a dump site 12 miles south of
Rockaway off Long Island. Over the following five decades, New Jersey and
Westchester County also used ocean dumping to disposal of sewage sludge. By
1979, 5.4 million metric tons of sewage sludge solids (5 percent) had been
dumped into the shallow (30-m) site (Mueller et al., 1982). Because of the
ecological effects, and the resulting political and public controversy (NACOA,
1981), ocean dumping at the 12-mile site was abandoned in 1985. Sludge disposal
was then moved to a deepwater site 106 miles offshore until this practice was
ended in 1992. New York City has subsequently constructed eight sludge dewa-
tering facilities and is relying on private contractors to handle its sewage sludge.
Long-range plans for the year 1998 called for direct application of dewatered
sludge for beneficial land use (Schwartz and Porter, 1994).
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
Beginning with decisions by local authorities to construct an organized
sewage collection system in Lower Manhattan as early as 1696, a complex
network of stormwater and sewage collection systems and wastewater treatment
plants has evolved over the past 300 years, initially to minimize nuisances and
protect public health, and most recently to restore and protect the estuarine
environment. In 1886 the first wastewater treatment plant was constructed to
protect bathing beaches at Coney Island. Following recommendations of a 1910
6-10
-------
Chapter 6: Hudson-Raritan Estuary Case Study
master plan for sewage treatment by the Sanitary Commission, New York City,
Passaic Valley, New Jersey, and Yonkers, New York, initiated construction
programs, beginning in the mid-1920s at Passaic Valley, for wastewater plants
(O'Connor, 1990).
Following a master plan from the Metropolitan Sewerage Commission, the
City of New York began construction of the first modern wastewater treatment
facility at Coney Island in 1935 and three plants discharging to the East River in
1938. Other locations also constructed municipal wastewater treatment plants at
that time. Modern treatment plants went on-line in 1938 at North and South
Yonkers, New York, designed for a combined discharge of 130 mgd into the
Hudson River; Passaic Valley, New Jersey, first constructed a plant in 1924 and
upgraded it in 1937 to 250-mgd capacity. By 1952 a total of 11 water pollution
control facilities were operational in New York City. Upgrades to seven of the
existing facilities during the 1950s and 1960s gradually resulted in improvements in
water quality within the harbor. By 1967 the largest New York City plant, Newton
Creek, came on-line discharging 310 mgd into the East River, with New York
City's wastewater treatment facilities accounting for a total effluent discharge of
approximately 1,000 mgd.
Driven by the regulatory controls of the 1972 Clean Water Act, public works
programs in New York City, New Jersey, Connecticut, and Westchester County
during the 1970s and 1980s upgraded municipal treatment facilities to full second-
ary treatment. In 1986 completion of the North River water pollution control plant
ended the discharge of 170 mgd of raw sewage into the Hudson River from
Manhattan, with secondary treatment attained in 1991. In 1987 completion of the
Red Hook water pollution control plant abated the discharge of 40 mgd of raw
sewage into the Lower East River from Brooklyn, with secondary treatment
attained in 1988. An additional 0.7 mgd of previously unsewered discharge was
captured beginning in 1993 when wastewater from Tottenville, Staten Island, was
connected to the 40-mgd Oakwood Beach water pollution control plant. Since the
completion of the North River plant in 1986 and Red Hook plant in 1987, all
wastewater collected in the total sewered area of about 2,000 square miles
(Figure 6-7) in the New York metropolitan region has been treated before dis-
charge into the estuary. Within the New York-New Jersey metropolitan region,
municipal sewage treatment plants serve approximately 16 million people and
discharge about 2,500 mgd (Brosnan and O'Shea, 1996a).
2500
2000-
| Combined Sewer Separate Sewer | | No Sewer
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980
Figure 6-7
Long-term trend of sewage
collection in the Hudson-
Raritan Estuary
metropolitan region, 1880-
1980.
Source: Suskowski, 1990,
6-11
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 6-8
Long-term trend in
untreated sewage
discharges to New York
Harbor.
Source: Brosnan and
O'Shea, 1996b.
1200-
1930 1940 ..... 1950
1960
1970
1990 2000
From 1979 to 1994, 13 of the 14 municipal water pollution control plants
operated by the city of New York were upgraded to full secondary treatment, as
defined by the 1972 Clean Water Act (Schwartz and Porter, 1994). The North
River (170 mgd) and Red Hook (45 mgd) plants, originally on line in 1986-1987 as
advanced primary facilities, were upgraded to full secondary plants in 1991 and
1989, respectively (Brosnan and O'Shea, 1996a). The Newton Creek water
pollution control plant is expected to be upgraded to full secondary treatment by
2007 (Schwartz and Porter, 1994). As a result of upgrades to existing plants and
construction of the North River and Red Hook plants, the discharge of raw
sewage has been reduced from 1,070 mgd in 1936 to less than 1 mgd by 1993
(Figure 6-8). Intermittent raw discharges, caused by malfunctions or
construction bypasses, have been reduced from 3.8 mgd in 1989 to 0.85 mgd by
1995 (O'Shea and Brosnan, 1997; Brosnan and O'Shea, 1996b).
The locations of municipal water pollution control plant (WPCP) discharges
(> 10 mgd) into the Hudson-Raritan estuary are shown in Figure 6-9. The
Hudson-Raritan Estuary receives pollutant loads from a number of different
sources in the drainage basin. Table 6-2 illustrates that the relative significance of
different sources is dependent on the pollutant considered. Combined sewer
Table 6-2. Pollutant loadings to the Hudson-Raritan Estuary (in percent).3 Source: Brosnan and O'Shea, 1996a.
Parameter
Flow
Fecal Coliform
BOD
TSS
Nitrogen
Phosphorus
Tributary
81
2
16
80
29
16
Municipal
Effluents
15
<0.1
58
11
63
75
Combined
Sewer
Overflow
1
89
19
5
2
4
Storm
Water
4
9
5
3
2
4
Other"
<0.5
<0.1
2
1
4
<0.5
Total Load
765 m3 s'1
2.1 X1016d'1
5.7X105kgd'1
2.4X106kgd'1
2.8X105kgd'1
2.3X105kgd1
a Modified from HydroQual (1991) based on data from the late 1980s. Values across may not equal
100% due to rounding.
b Other = industrial discharges, landfill leachate, and direct atmospheric deposition combined.
6-12
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Chapter 6: Hudson-Raritan Estuary Case Study
Figure 6-9
Location of harbor survey sampling sites and municipal water pollution control plants in New York Harbor.
Source: Brosnan and O'Shea, 1996b.
NYC WATER POLL. CONTROL PLANTS *
North River (183 mgd)
Wards Island (267 mgd)
Bowery Bay (128 mgd)
Hunts Point (146 mgd)
Tallman Island (59 mgd)
Newtown Creek (286 mgd)
Red Hook (45 mgd)
Owls Head (128 mgd)
03 Coney Island (104 mgd)
26th Ward (72 mgd)
Jamaica (77 mgd)
Rockaway (23 mgd)
Port Richmond (41 mgd)
Oakwood Beach (27 mgd)
* Flows represent 1/93 -11/93
averages, (total flows)
• Other WPCP's >10 mgd.
WESTCHESTER
COUNTY
s
Long
Island
Sound
QUEENS
NEW JERSEY
BROOKLYN
STATEN
ISLAND
ATLANTIC OCEAN
6-13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 6-3. Distribution of
HydroQual, 1991; O'Shea
Waterway
Hudson River
East River
Upper New York Bay
Jamaica Bay
Lower New York Bay
Arthur Kill
Kill van Kull
Raritan River
Hackensack River
Passaic River
Total
wastewater flows into New York
and Brosnan, 1997.
WPCPsa
(2,500 mgd)
Flow (mgd)
375
1,050
375
300
125
100
50
<25
100
0
2,500
% Total
15
42
15
12
5%
4%
2%
<1%
4%
0%
Harbor waterways. Sources:
Direct Industrial Discharges
(52 mgd)
Flow (mgd)
3.1
0.0
1.0
0.0
0.0
40.0
0.0
2.1
4.2
1.0
51.4
% Total
6%
0%
2%
0%
0%
78
0%
4%
8%
2%
a Some municipal dischargers (WPCPs) include industrial dischargers.
overflows, for example, account for only 1 percent of the total freshwater input to
the harbor but contribute 89 percent of the total loading of fecal coliform bacteria
(Brosnan and O'Shea, 1996a). Effluent from water pollution control plants
contributes about one-half to three-quarters of the total load of BOD5 and nutri-
ents, while watershed runoff via tributaries accounts for 80 percent of the total
suspended solids (TSS) load. Table 6-3 presents a summary of the distribution of
effluent flows from municipal (WPCPs) and industrial point source discharges to
New York Harbor waterways. As presented in Table 6-3, approximately 2,500
mgd of treated wastewater was discharged in 1995 from 81 water pollution
control facilities located in New York City, six New Jersey coastal counties, two
coastal Connecticut counties, and Westchester and Rockland counties in New
York (O'Shea and Brosnan, 1997). Of the total 2,500 mgd, facilities operated by
the city of New York accounted for 1,490 mgd in 1995.
With the construction and upgrade of WPCPs, the relative contributions of
effluent flow and BOD5 loading shifted from less-than-secondary to secondary
point sources. Figure 6-10 shows the contributions of raw, primary, and secondary
facilities to the effluent flow trend of approximately 2,500 mgd from 1970 through
1987. Less than 500 mgd (approximately 20 percent) was accounted for by less-
than-secondary dischargers by 1987. With the upgrade of the Coney Island plant
to full secondary in 1994, effluent flow from less-than-secondary facilities has
been abated completely. Trends in the reduction of effluent BOD5 loading to the
harbor (Figure 6-11) show that total BOD5 loads from municipal WWTPs have
been reduced from approximately 962 metric tons/day in 1970-1974 to 369 metric
tons/day by 1987. With the exception of the Newton Creek facility, all municipal
facilities in New York City had been upgraded to secondary treatment by 1994-
1995. Effluent BOD5 loading from municipal facilities discharging to the Hudson-
Raritan estuary was further reduced to 214 metric tons/day by 1994-1995
(HydroQual, 1999). Most of this substantial reduction is attributed to the elimina-
6-14
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Chapter 6: Hudson-Raritan Estuary Case Study
3000
25001
2000-
O)
I
EL
1500-
1970-74
1979-80
1987
Raw
Primary
I Secondary mj| Industrial
1200
1970-74
1979-80
1987
Figure6-10
Long-term trends in the
source contribution of point
source effluent flow to New
York Harbor.
Source: HydroQual, 1991.
Figure 6-11
Long-term trends in the
source contributions of
point source effluent BOD5
loads to New York Harbor.
Source: HydroQual, 1991.
tion of raw sewage discharges on the west side of Manhattan (North River plant)
and Brooklyn (Red Hook plant) and upgrades to full secondary treatment. Based
on an empirical relationship of BOD5 loading and observed DO saturation records
in the Lower East River (Suszkowski, 1990), historical trends in effluent BOD5
loading have been estimated for the Lower East River (Figure 6-12). The in-
crease in BOD5 loading from 1910 to 1930 is attributed to population growth and
an expanding sewage collection system (see Figure 6-7), while the reduction in
loading from 1930 to 1940 resulted from the construction of three primary treat-
ment plants during the 1930s. After the mid-1960s, the progressive decline in
BOD5 loading was driven by upgrades to full secondary treatment and the
elimination of raw sewage discharges from Brooklyn with construction of the Red
Hook facility as an advanced primary plant in 1987.
The long-term trend (1880-1980) of historical loading of copper and lead to
New York Harbor (Figure 6-13) reflects increasing urbanization and uncontrolled
wastewater discharges from industrial activity in the metropolitan region from
1880 through 1970. The reduction in loading of these metals after 1970, resulting
from the industrial pretreatment program, corrosion controls, and effluent controls
on industrial discharges, corresponds to a decrease in sediment levels of copper
6- 15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
and lead in the Hudson estuary (Figure 6-14). Studies conducted at Columbia
University have documented a 50 to 90 percent reduction from the 1960s and
1970s in most trace metals and chlorinated organic compounds in fine-grained
sediments of the Hudson River (Chillrud, 1996). Sediment toxicity, however, has
been identified for the Upper East River, Arthur Kill, Newark Bay, and Sandy
Hook Bay. The observed distribution of sediment toxicity appears to be most
strongly related to polynuclear aromatic hydrocarbons (PAHs) rather than trace
metals (Wolfe et al., 1996). Historical point and nonpoint source loading estimates
for the Hudson-Raritan estuary are presented elsewhere for other trace metals,
PCBs, total suspended solids (HydroQual, 1991), total organic carbon (Swaney et
al., 1996; Howarth et al., 1996) and nutrients (HydroQual, 1991, 1999; Carpenter,
1987). Using a steady-state toxics model, the New York-New Jersey Harbor
Estuary Program has also developed mass balance analyses for copper, nickel,
and lead and a preliminary mass balance for mercury and PCBs (HydroQual,
1995b).
Long-term water quality records for most locations in the estuary clearly
illustrate degradation from population growth and inadequate sewage treatment
through the mid-1960s and gradual improvement following construction of waste-
600
Figure 6-12
Long-term trends of BOD5
loads to the Lower East
River.
Source: Suskowski, 1990.
0
1910 1920 1930 1940 1950 1960 1970 1980 1990
Figure 6-13
Long-term trend of copper
and lead loads to New
York Harbor.
Source: Suskowski, 1990.
1880 1
1990
—- Lead
^g Copper
6-16
-------
Chapter 6: Hudson-Raritan Estuary Case Study
Figure 6-14
Time history of copper and
lead in sediment core in
the low-salinity reach of the
Hudson estuary.
Source: Valette-Silver,
1993.
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995
water treatment plants and implementation of secondary treatment. Using histori-
cal data collected at 40 stations in the harbor from 1968 to 1993, an analysis of
harborwide long-term trends clearly documents more than an order-of-magnitude
improvement in total coliform and fecal coliform concentrations (Figure 6-15).
The dramatic decline in bacterial levels is attributed to water pollution control
infrastructure improvements that eliminated raw sewage discharges and upgraded
all water pollution control plants to include disinfection by chlorination (O'Shea
and Brosnan, 1997). Other improvements, reductions of approximately 50 percent
in bacterial levels for most areas of the harbor, are attributed to increased surveil-
lance and maintenance of the entire sewage distribution system, including the
capture of combined sewage during rain events (Brosnan and O'Shea, 1996b).
Long-term summer DO saturation records, collected almost continuously
since 1909 at a station in the Hudson River near 42nd Street on the west side of
Manhattan (Figure 6-16) and stations at Baretto Point and 23rd Street in the
Upper and Lower East River (Figure 6-17), clearly document the beneficial
impact of upgrading water pollution control facilities to full secondary treatment.
Over a 40-year period from the 1920s through the 1960s, summer oxygen satura-
tion levels were only about 35 percent to 50 percent at the surface and 25 percent
to 40 percent in bottom waters. As a result of significant reductions in biochemi-
cal oxygen demand loading (see Figures 6-11 and 6-12), DO saturation levels
increased to about 90 percent at the surface and greater than 60 percent in the
bottom waters (Brosnan and O'Shea, 1996a). DO concentrations have increased
significantly since the 1980s harborwide (Brosnan and O'Shea, 1996a; Parker and
O'Reilly, 1991). In many waterways, the greatest oxygen and BOD5 improve-
ments were recorded between 1968 and 1984, coinciding with the greatest
WPCP construction and upgrading activity (O'Shea and Brosnan, 1997). Analysis
of data for stations from 1968 to 1995 documents reductions in ammonia-nitrogen
(Figure 6-18) and decreases in BOD5 (Figure 6-19) throughout New York
Harbor; exceptions to these decreasing trends include stations in Jamaica Bay
and scattered stations in Lower New York Bay and the Upper East River
(O'Shea and Brosnan, 1997).
Although not generally appreciated, the poor water quality conditions,
particularly low DO levels, that characterized New York Harbor for most of the
20th century actually had a beneficial effect for shipping activities because
6-17
-------
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00
-------
Chapter 6: Hudson-Raritan Estuary Case Study
wooden pilings and other submerged wooden structures were not destroyed by
pollution-intolerant marine borers. During the 19th century before water quality
had deteriorated in the harbor, abundant populations of shipworms (teredos) and
gribbles (limnorid) quickly devoured driftwood (naturally occurring) and wooden
pilings (man-made). This natural ecological activity probably kept the harbor clear
of driftwood, but it created severe problems for commercial shipping interests
because untreated wooden pilings needed to be replaced after only about 7-10
years (Port Authority of New York, 1988). As water pollution problems increased
in the harbor, populations of marine borers declined to such a level that, ironically,
wooden pilings and other submerged wooden structures were preserved for many
years while submerged in the noxious, oxygen-depleted waters laden with oil,
bilge waste, and toxic chemicals. The dramatic improvements in water quality
conditions in New York Harbor, as well as other east and west coast harbors,
have resulted in a resurgence of thriving populations of marine borers since the
mid-1980s (Gruson, 1993) (Figure 6-20). The population boom of marine borers
has resulted in severe infestation and rapid deterioration and collapse of wooden
Figure 6-18
Long-term trend in
summer mean inorganic
nitrogen. Data represent
harborwide composite of
40 stations monitored
since at least 1970.
Source: O'Shea and
Brosnan, 1997.
70 1975 1980 1985 1990 1995
• NH3-N
NO3-N+NO2-N
Figure 6-19
Long-term trend in
summer mean BOD5. Data
represent harborwide
composite of 40 stations
monitored since at least
1970.
Source: O'Shea and
Brosnan, 1997.
1975 1980 1985 1990 1995
Surface
Bottom
6-19
-------
Progress in Wafer Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
pilings and other submerged wooden structures in New York Harbor from JFK
International Airport to New Jersey, including Brooklyn, Staten Island, and the
east and west sides of Manhattan (Randolph, 1998; Abood et al, 1995; Metzger
andAbood, 1998; Schwartz and Porter, 1994).
Over the past several years, state-of-the-art coupled hydrodynamic and
water quality models have been developed for water quality management studies
of the harbor, including New York City's Harbor-Wide Eutrophication Model and,
most recently, the System-Wide Eutrophication Model (SWEM) (HydroQual,
1995a, 1996, 1999). Earlier models, developed for USEPA's 208 Study of the
harbor (Hazen and Sawyer, 1978; Higgins et al., 1978; Leo et al., 1978; O'Connor
and Mueller, 1984), have been used to assess the impact of secondary treatment
requirements on DO in the harbor. The more recent New York City models,
employing improved loading estimates and state-of-the-art hydrodynamics
(Blumberg et al., 1997), are being used to determine the feasibility and effective-
ness of management alternatives for New York City point sources of nitrogen.
For example, SWEM will enable New York City to evaluate options as part of the
facility planning for the Newton Creek WPCP, the last remaining plant operated
by the city of New York to be upgraded to secondary treatment (HydroQual,
1999). This model is further assisting the New York-New Jersey Harbor Estuary
Program in understanding the complex relationships between physical transport
processes, nitrogen loading, algal biomass, and DO in New York Harbor, the New
York Bight, and Long Island Sound (HEP, 1996).
Impact of Wastewater Treatment:
Recreation and Living Resources Trends
Since 1968 the New York City Council has required the New York City
Department of Public Health to notify the Department of Parks of beaches that
pose a potential health risk to the public. Such beaches were traditionally posted
with wet weather advisories, following occurrences of heavy or prolonged
Figure 6-20
Trends in marine borer
activity in Upper New York
Harbor.
Source: Port Authority of
New York, 1988.
16 sites including Port Newark
1970
1975
1980
1985
1990
-*- Limnoria -»
Teredo
6-20
-------
Chapter 6: Hudson-Raritan Estuary Case Study
rainstorms. These postings have long been replaced with seasonal wet weather
advisory postings. The advisories are based on the occurrence of high fecal
coliform bacteria concentrations, which may indicate the presence of raw or
partially treated sewage and the likely presence of waterborne pathogens.
Diseases associated with recreational swimming waters include typhoid fever,
gastroenteritis, swimmer's itch, swimmer's ear, and some viral infections such as
infectious hepatitis (NJDEP, 1990).
The most important source of pollution, contributing about 89 percent of the
total fecal coliform bacteria load to the harbor, is wet weather CSOs (Brosnan
and O'Shea, 1996a). Large volumes of water generated during rainstorm events,
when combined with the regular volume of sewage, overwhelm the capacity of
the collection system and discharge the mixture of storm runoff and raw waste-
water directly into the harbor. During wet weather events, water quality may be
seriously degraded.
Before 1900 untreated wastewater caused severe outbreaks of disease
associated with exposure pathways such as shellfish consumption and recre-
ational swimming. Conditions improved somewhat as sewage treatment plants
adopted primary treatment as a practice to settle out the solids in wastewater
before discharge to the harbor. Pathogen reduction was further enhanced by
upgrading water pollution control facilities to secondary treatment with chlorina-
tion of the effluent for disinfection. Improvements in municipal wastewater
treatment practices have significantly reduced the incidence of waterborne
disease outbreaks. Typhoid fever, once a serious swimming-related disease, for
example, has not been reported in the last 30 to 40 years (NJDEP, 1990).
During the 1970s and 1980s significant efforts were made to construct and
upgrade WPCPs in the Hudson-Raritan Estuary to attain secondary levels of
wastewater treatment as mandated by the 1972 Clean Water Act. With upgrades
and chlorination of effluent, the discharge of raw wastewater has been reduced
from 450 mgd in 1970 to less than 5 mgd by 1988 and essentially zero by 1993
(see Figure 6-8). The most dramatic improvement in bacterial conditions in the
harbor occurred in 1986 with the completion of the North River WPCP in Man-
hattan. Before construction of the primary facility, 170 mgd of raw sewage was
discharged into the Hudson River from 50 outfalls on the west side of Manhattan
(Brosnan and O'Shea, 1996a). Treatment of the raw sewage and year-round
disinfection resulted in a dramatic decline in fecal coliform concentrations. The
1986 data revealed a 78 percent decrease in the fecal coliform concentrations in
the Hudson river compared to values measured in 1985 before the primary plant
came on-line. When the 45-mgd Red Hook WPCP went on-line in 1987 in
Brooklyn, abating the raw sewage discharge from 33 outfalls, fecal coliform
concentrations in the East and Lower Hudson Rivers declined by 69 percent
within 2 years. Continued improvements in water quality and decreases in fecal
coliform bacterial concentrations on the order of 50 percent from 1989 to 1995
are attributed to improved maintenance and surveillance of the sewage treatment
system. Management actions that have contributed to these improvements in
water quality include abatement of illegal connections, reduced raw sewage
bypasses, and increased capture of combined sewage during rain events (Brosnan
and O'Shea, 1996b).
"Snapshots" of the distribution of total coliform bacteria from 1972 to 1995
in surface waters of the harbor (Figure 6-21) clearly document the significant
6-21
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
reductions in bacterial concentrations that resulted from implementation of
controls to reduce water pollution in the harbor. Following completion of the North
River and Red Hook WPCPs in 1986 and 1987, respectively, total coliform
distributions in 1988 demonstrated significant improvements compared to 1985
before these two plants came on-line. The improvements attributed to CSO
controls are also quite apparent: total coliform levels in the harbor declined by
more than 50 percent at 45 of 52 stations in 1995 and compliance with water
quality standards improved from 87 percent in 1989 to 98 percent in 1995
(Brosnan and Heckler, 1996).
Historically, many public bathing beaches in Lower New York Harbor have
been closed to swimming to protect public health because of high bacterial levels
that consistently violated water quality standards for primary contact. As a result
of the construction and upgrade of water pollution control plants in the harbor, the
significant harborwide reductions in coliform bacteria levels (see Figure 6-16)
allowed the reopening of public beaches that had been closed for decades. In
1988 Seagate Beach on Coney Island was opened to swimming for the first time
in 40 years. South Beach and Midland Beach on Staten Island, closed since the
early 1970s, were opened for swimming in 1992. In addition to beach closings
because of high bacterial levels, recreational beaches are also closed because of
strandings of floatable garbage, including medical waste, on the beaches. As a
result of increased abatement and control of discharges of floatable debris, beach
closings in New York and New Jersey have been greatly reduced. As of 1996, no
beaches in New York City had been closed because of floatables since 1989;
New Jersey beaches had not been closed since 1991 (Brosnan and Heckler,
1996).
In addition to closing bathing beaches, the presence of pathogens and
pathogenic indicator organisms directly affects shellfish resources. Because
pathogen levels were significantly reduced by improved wastewater treatment
and year-round chlorination, 67,864 acres of shellfish beds in the estuary have
been upgraded since 1985, including removal of seasonal restrictions for 16,000
acres in the New York Bight in 1988, and 13,000 acres in Raritan Bay in 1989
(Gottholm et al., 1993; NJDEP, 1990). Additionally, 1,000 acres of shellfish waters
in the Navesink River are being considered for upgrading to a "seasonally ap-
proved" classification (HEP, 1996). Shellfishing resources to a greater extent than
finfish populations are directly related to improvements in wastewater treatment
(Sullivan, 1991).
Although the long-term trends in the abundance of fish such as American
shad and striped bass in coastal waters may be the result of degraded water
quality, the National Marine Fisheries Service has indicated that overfishing,
rather than changes in water quality, is probably the most significant cause of
present changes in resource abundance for many species (Sullivan, 1991). The
principal commercial fishery of the lower Hudson River estuary is for American
shad. Shad landings from 1979 to 1989 were maintained, whereas landings of
whiting, red hake, scup, and weakfish decreased during the last decade
(Woodhead, 1991). Improved water quality has expanded the spawning area
available for American shad (Sullivan, 1991). The prevalence of fin rot in winter
flounder declined tenfold in the New York Bight region between 1973 and 1978
for reasons that are not clear (Swanson et al., 1990). Although the causes of fin
rot are not well understood, it tends to be more prevalent in shallow inshore
6-22
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Chapter 6: Hudson-Raritan Estuary Case Study
Figure 6-21
Total coliform trends in surface waters of New York Harbor. Summer geometric means for 1972, 1985, 1988, and 1995.
Source: O'Shea and Brosnan, 1997.
1972
Pre-WPCP Upgrades
NORTH
N
W
NEW JERSEY
ATLANTIC OCEAN
Itotai toy
1985
Post-WPCP Upgrade,
Pre-North River and
Red Hook WPCP's
NEW JERSEY
1988
Post-North River (1986)
and Red Hook (1987)
NEW JERSEY
1995
improvements from the
Nine Minimum
CSO Controls
WESTCHESTER
COUNTY
w^f'
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NEW JERSEY ^>
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KEY: UNIT=MPN/100ML
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(NOTE: This analysis does not necessarily imply compliance.)
VOR fm«o»v»n«.«£»Tcn3»iB*»*Tc««»6j»»* mom
6-23
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
waters receiving municipal effluents, and therefore the decline in the incidence of
fin rot lesions might reflect improvements at wastewater treatment plants
(Sullivan, 1991).
Populations of some birds in the Hudson Raritan Estuary have historically
been influenced by many aspects of this complex urban ecosystem other than
water quality. Notable among these factors is the decimation of local bird popula-
tions in the latter half of the 19th century by the hunting and milliner's trade
(Sullivan, 1991). Before the passage of federal protective legislation, such as the
1913 Migratory Bird Treaty, annual catches for food and feathers totaled more
than a million birds per year. Even small songbirds, such as robins, were sought
for sale in commercial markets. By 1884 the once abundant populations of
common terns, least terns, and piping plovers, formerly present between Coney
Island and Fire Island, had been reduced to but a few individuals. Populations of
common and roseate terns, herons, snowy egrets, and many other species were
similarly affected by hunting.
Populations gradually recovered over the next several decades until develop-
ment and associated draining and spraying of wetlands for mosquito control
encroached on, and degraded, waterfowl habitat. Between the late 1940s and its
ban in 1972, DDT was heavily applied to the salt marshes of Long Island and
New Jersey; the New Jersey marshes received the heaviest applications for the
longest period of time. The DDT was transferred up the food chain to fish and
shellfish, which are an important food source for many coastal birds in the harbor.
DDT accumulated in bird tissues and contributed to the decline in reproductive
success by affecting eggshell thickness. The osprey was probably the species
most affected in the Hudson-Raritan Estuary area, although bald eagles and
herons were also affected.
Recent concerns for shorebirds include the high concentrations of industrial
chemicals such as PCBs measured in mallards, black ducks, scaup, and osprey.
Due to the many factors contributing to the abundance of shorebirds and the fact
that they can be exposed to more than one geographic area through migration,
there is only a tenuous linkage between improved water pollution control efforts
and bird populations. Overwintering populations of waterfowl, however, have
generally remained stable since the 1980s (Sullivan, 1991). For example, the
Canada goose populations of New Jersey increased from about 6,000 in 1975 to
23,200 in 1981 to 124,000 in 1990, a record high for the state. This increase is
most likely the result of displacement of geese from other states, particularly
Maryland.
Most remarkable among bird population recoveries is the return of herons to
the heavily industrialized and highly polluted northwestern portion of Staten Island
along the Arthur Kill and Kill Van Kull waterways. In the urban wetlands, un-
daunted by nearby oil refineries and chemical manufacturing plants, herons and
other wading birds are making a comeback. The Harbor Herons Complex, first
documented in the industrial Arthur Kill waterway in the 1970s, has become a
regionally significant heron and egret nesting rookery (HEP, 1996). In 1974 snowy
egrets, cattle egrets, and black-crowned night-herons began nesting on Shooters
Island; in 1978 nesting snowy egrets and cattle egrets were found on Frail's
Island, a 88-acre high marsh that in the past had served as a disposal site for
dredged spoils. By 1981 these birds were joined by glossy ibises, great egrets, and
black-crowned night-herons. In 1989 snowy egrets, glossy ibises, cattle egrets,
6-24
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Chapter 6: Hudson-Raritan Estuary Case Study
black-crowned night-herons, yellow-crowned night-herons, little blue herons, and
great egrets were found on the nearby Isle of Meadows. Ospreys, now nesting in
portions of the harbor core area where they had been absent for decades (prima-
rily because of bioaccumulation of DDT), have rapidly become so numerous as to
be considered a nuisance by boaters and fishermen. Ten percent of the east coast
population of the federally endangered peregrine falcon is located in the Hudson-
Raritan Estuary metropolitan area (HEP, 1996).
Fish-eating bird populations have thrived despite the fact that sluggish
circulation and urban runoff and municipal and industrial wasteloads characterize
these waterways (Hydroqual, Inc., 1991). The Arthur Kill waterway is possibly
one of the sites of poorest water quality in New York Harbor. Summer mean DO
concentrations in the Arthur Kill, ranging from less than 1 mg/L to about 3 mg/L
from 1940 to the mid-1970s, however, steadily improved during the 1970s to
concentrations above 5 mg/L by the mid-1980s (Figure 6-22) (Keller et al., 1991;
O'Shea and Brosnan, 1997). Average summer concentrations of DO at Shooters
Island in the Kill Van Kull further reflect this trend of improvements, increasing
from 30 percent in 1974 to near 60 percent saturation in 1995 (O'Shea and
Brosnan, 1997). Improvements in DO concentrations, as well as habitat protection
efforts by the New York City Audubon Society, may have contributed to the
success of populations of herons that feed on pollution-intolerant young fish in the
Arthur Kill and its associated tidal creeks and wetlands. A 1988-1989 census of
wading bird breeding populations indicated approximately 900-1,200 pairs of
breeding herons, egrets, and ibises that constitute possibly the largest colonial
waterbird rookery complex in New York State (Trust for Public Lands, 1990).
Summary and Conclusions
In the three centuries since the Governor of New York ordered a sewer
system to be constructed in Lower Manhattan, New York City has made consid-
erable progress in protecting public health and improving the water quality of the
harbor. Since the early 1900s when the city of New York instituted one of the
Nation's first long-term water quality monitoring programs in New York Harbor,
Figure 6-22
Long-term trend in
summer (July-September)
mean, minimum, and
maximum DO in the Arthur
Kill (RF1-02030104003).
Source: USEPA (STORET).
1940
19ST
1960
1970
1980
T990
Mean Min Max
6-25
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
the city's efforts to improve the waters of New York have included constructing,
maintaining, and upgrading the infrastructure for wastewater collection and
treatment, pollution prevention and remediation, water quality monitoring, and
programs to protect the natural resources of the estuary and restore disrupted
natural drainage patterns to mitigate urban runoff problems.
Although construction and upgrades of municipal wastewater treatment
facilities resulted in some water quality improvements beginning in the 1950s, the
greatest strides in improving ecological conditions in the harbor can be attributed
to new construction and upgrades of municipal wastewater plants in the Hudson-
Raritan metropolitan region during the 1970s, largely stimulated by the regulatory
requirements of the 1972 CWA. Based on assessments of long-term water quality
monitoring data and other environmental indicators, the ecological and water
quality conditions of New York Harbor are the best they have been since the
early 1900s (NYCDEP, 1999).
Biological indicators of environmental improvement in New York Harbor
include the reestablishment of breeding populations of waterfowl (e.g., peregrine
falcons, ospreys, herons) in many areas of the estuary, the recovery of Hudson
River shortnose sturgeon to record populations, the decline of PCBs in striped
bass, and a relaxation of New York State advisories for human consumption of
striped bass in parts of the Hudson River. Marine organisms long absent from the
waters of the harbor because of poor water quality conditions are now thriving as
a result of the cleanup of the harbor. The resurgence of pollution-intolerant
benthic organisms in Lower New York Bay and the heavy reinfestation of
submerged wooden pilings by marine borers throughout the Hudson-Raritan
estuary are strong evidence of the improvement in the ecological condition of the
harbor.
Water quality indicators of environmental improvement in the harbor that
can be attributed to upgrades of wastewater treatment facilities include significant
declines in total and fecal coliform bacteria, dramatic improvements in dissolved
oxygen levels, and declines in ammonia-nitrogen and BOD5 in most areas of the
Hudson-Raritan estuary. Controls on releases of heavy metals and toxic chemi-
cals have resulted in a 50-90 percent reduction relative to peak levels of trace
metals and chlorinated organic compounds associated with fine-grained sediments
in the Hudson River. The 1972 federal ban on lead in gasoline has resulted in
declines in lead in the sediments in New York Harbor and many other waterways
(O'Shea and Brosnan, 1997).
Resource use indicators of environmental improvements in the harbor
include the bacteria-related upgrading of the status of 68,000 acres of shellfish
beds, including the lifting of restrictions on harvesting shellfish in 30,000 acres in
Raritan Bay and off the Rockaways in the late 1980s. As a result of the dramatic
declines in coliform bacterial levels, all New York City beaches, historically closed
to swimming since the 1950s, have been open since 1992 and wet-weather
swimming advisories have been lifted for all but three beaches (NYCDEP, 1999).
These bacteria-related improvements in public and commercial uses of the harbor
can be attributed to the continued construction and upgrading of the city's munici-
pal water pollution control plants, the elimination of raw and illegal waste dis-
charges, and the increased efficiency of the combined sewer system (Brosnan
and O'Shea, 1996b; Brosnan and Heckler, 1996).
6-26
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Chapter 6: Hudson-Raritan Estuary Case Study
As a result of the clean-up efforts to date in the harbor, the public has
enjoyed greatly increased opportunities for recreational uses such as swimming,
boating, and fishing. The improvements in water quality also provide substantial
benefits to the local economy through commercial fishing and other water-based
revenue-generating activities. Although tremendous ecological improvements
have resulted from water pollution control efforts implemented since the 1970s, a
number of environmental problems remain to be solved for the Hudson-Raritan
Estuary. Some contemporary concerns and issues include, for example, contami-
nation of sediments and restrictions on dredge spoil disposal, remaining fish
advisories for human consumption, episodic low dissolved oxygen, the occurrence
of nuisance algal blooms and effluent controls on nitrogen discharged to the
estuary, and increasing nonpoint source runoff from overdevelopment in the
drainage basin of the estuary (NYCDEP, 1999). The success of continued water
pollution control efforts to remedy these concerns in the Hudson-Raritan Estuary
will require financial support from all levels of government, enhanced public
awareness about the resource value of the estuary, and strong public stakeholder
support for regional coordination of environmental control programs throughout
the entire Hudson-Raritan watershed.
References
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Brosnan, T.M., and RC. Heckler. 1996. The benefits of CSO control: New York
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HEP. 1996. Comprehensive conservation and management plan, NY/NJ
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HydroQual, Inc. 1991. Assessment of pollutant loadings to New York-New
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HydroQual, Inc. 1995a. Analysis of factors affecting historical dissolved
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HydroQual, Inc., Mahwah, NJ.
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wasteload allocations (TMDLs/WLAs) procedure for toxic metals in NY/
NJ Harbor. Job No. TETR0103. Prepared for the U. S. Environmental
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Circular No. 686. U.S. Department of the Interior, U.S. Geological Survey.
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University of Rhode Island.
Leo, W.M., J.P. St. John, and D.J. O'Connor. 1978. Seasonal steady state
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McHugh, J.L., R.R. Young, and W.M. Wise. 1990. Historical trends in the
abundance and distribution of living marine resources in the system. In
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and R.V. Thomann (co-chairmen), Regional Conference cosponsored by
Manhattan College and the Management Conferences for the Long Island
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(HEP), and the New York Bight Restoration Plan (NYBRP), March 12-14,
1990.
Metzger, S.G., and K.A. Abood. 1998. The Linmoria has landed! In Ports '98,
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neers, New York.
Mueller, J.A., T.A. Gerrish, and M.C. Casey. 1982. Contaminant inputs to the
Hudson-Raritan Estuary. NOAA Tech. Mem. OMPA-21. Boulder, CO.
NACOA. 1981. The role of the ocean in a waste management strategy.
Special Report to the President and Congress. January. National Advisory
Committee on Oceans and Atmospheres, Washington, DC.
NJDEP. 1990. Characterization of pathogen contamination in the NY-NJ
Harbor estuary. Prepared by the New Jersey Department of Environmental
Protection Pathogen Workshop. (Also included was a February 6, 1992,
addendum.)
NYCDEP. 1999. 1998 New York Harbor water quality regional summary. New
York City Dept. Environmental Protection, New York, NY. .
O'Connor, D.J. 1990. A historical perspective: engineering and scientific. In
Cleaning up our coastal waters: an unfinished agenda, ed. K. Bricke,
and R.V. Thomann (co-chairmen), pp. 49-67. Regional conference cospon-
sored by Manhattan College and the Management Conferences for the Long
Island Sound Study (LISS), the New York-New Jersey Harbor Estuary
Program (HEP), and the New York Bight Restoration Plan (NYBRP),
March 12-14, 1990.
O'Connor, D.J., and J.A. Mueller. 1984. Water quality analysis of the New York
Harbor complex. ASCE, Jour. Environ. Eng. Div. 110(6): 1027-1047.
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New York Bight Atlas Monograph 27. New York Sea Grant Institute,
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Parker, C.A., and J.E. O'Reilly. 1991. Oxygen depletion in Long Island Sound:
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Chapter 6: Hudson-Raritan Estuary Case Study
Randolph, E. 1998, January 26. Terror of the Hudson River is back. The Los
Angeles Times, p. A-5.
Revkin, A.C. 1997, September 17. High PCB level is found in a Hudson bald
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Schwartz, J.J., and K.S. Porter. 1994. The state of the city's waters: 1994. the
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waters: An unfinished agenda, ed. K. Bricke, and R.V. Thomann (co-
chairmen). Regional conference cosponsored by Manhattan College and the
Management Conferences for the Long Island Sound Study, the New York-
New Jersey Harbor Estuary Program, and the New York Bight Restoration
Plan, March 12-14, 1990.
Thomann, R.V., J.A. Mueller, R.P. Winfield, and C. Huang. 1991. Model of fate
and accumulation of PCB homologues in Hudson Estuary. Journal of
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preserving a unique urban wildlife habitat and wetland resource in
northwestern Staten Island. Published by the Trust for Public Land in
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Census - Population Division, Washington, DC.
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USGS. 1999. Streamflow data downloaded from U.S. Geological Survey, United
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Wiseman, W. 1997. State University of New York at Stony Brook, Marine
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December 23, 1997.
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Harbor Estuary Program.
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Chapter 7
Delaware Estuary
Case Study
The Mid-Atlantic Basin (Hydrologic Region 2),
covering a drainage area of 111,417 square
miles, includes some of the major rivers in the
continental United States. Figure 7-1 highlights the
location of the basin and the Delaware estuary, the case
study watershed profiled in this chapter.
With a length of 390 miles and a drainage area of
11,440 square miles, the Delaware River ranks 17th
among the 135 U.S. rivers that are more than 100
miles in length. On the basis of mean annual dis-
charge (1941-1970), the Delaware ranks 28th
(17,200 cfs) of large rivers in the United States
(Iseri and Langbein, 1974). Urban-industrial areas
in the watershed caused severe water pollution
problems during the 1950s and 1960s (see Table 4-2).
This chapter presents long-term trends in population,
municipal wastewater infrastructure and effluent loading of pollut-
ants, ambient water quality, environmental resources, and uses of the
Delaware Estuary. Data sources include USEPA's national water
quality database (STORET), published technical literature, and unpub-
lished technical reports ("grey" literature) obtained from local agency sources.
The Delaware River, formed by the confluence of its east and west
branches in the Catskill Mountains near Hancock, New York, on the
Pennsylvania-New York state line, becomes tidal at Trenton, New Jersey (Figure
7-2). The first 86 miles of the tidal river are the Delaware River estuary, which
flows by Trenton, New Jersey; Philadelphia, Pennsylvania; Camden, New Jersey
and Wilmington, Delaware. This major urban-industrial area has a tremendous
impact on the water quality of the river. In this area, the Delaware River estuary
flows along the boundary between the Piedmont Plateau and the Atlantic Coastal
Plain. A large number of municipal and industrial wastewater facilities discharge
to the Delaware River, with municipal water pollution control plants accounting
for the largest component of BOD5 loading. In general, water quality is good at
the head of the tide at Trenton (RM 134.3), but it begins to deteriorate down-
stream.
Figure 7-1
Hydrologic Region 2 and
Delaware estuary
watershed.
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76
Figure 7-2
Location map of the Lower
Delaware River-Delaware
Bay. (River miles shown
are distances from the
Cape May, NJ, to Cape
Henlopen, DE, transect.)
76
From the 1930s through the 1970s, water quality conditions were very poor.
Depleted DO levels were recorded in the region from Torresdale (RM 110.7) to
Eddystone (RM 84.0) as a result of wastewater loading from Philadelphia (RM
110-93). Since the mid-1980s water quality conditions in the estuary have im-
proved significantly.
Physical Setting and Hydrology
The Delaware River originates in the south-central area of New York State
and flows 390 miles in a southerly direction to the Atlantic Ocean, separating
New Jersey on its eastern bank from Pennsylvania and Delaware on its west.
The total drainage area at the mouth of the river at Listen Point on Delaware Bay
is 11,440 square miles, of which 6,780 square miles lie above the gaging station at
Trenton, New Jersey (Iseri and Langbein, 1974). The major tributary to the
Delaware Estuary is the Schuylkill River, which joins the main stream in the
vicinity of Philadelphia, Pennsylvania. The Schuylkill has a drainage area of 1,890
square miles at the Fairmount Dam, 8 miles above the mouth. In addition to the
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Chapter 7: Delaware Estuary Case Study
Schuykill River, the other major tributaries to the Delaware estuary include
Assunpink Creek, Crosswicks Creek, Rancocas Creek, Neshaminy Creek,
Cooper River, Chester Creek, the Christina River, and the Salem River. Figure 7-3
presents long-term statistics of summer streamflow from the USGS gaging station
at Trenton, New Jersey, from 1940 to 1995. The extreme drought conditions of
the mid-1960s are quite apparent in the long-term record (1962-1966). Seasonal
variation of freshwater flow of the Delaware River is characterized by high flow
from March through May, with a peak flow of 21,423 cfs in April. Low-flow
conditions typically occur from July through October, with the monthly minimum
flow of 5,830 cfs recorded during September (Figure 7-4). From July through
October, low-flow in the river is typically augmented by releases from reservoirs.
During dry conditions, reservoir releases, regulated to maintain a minimum flow of
2,500-3,000 cfs at Trenton, can be greater than 60 percent of the inflow to the
estuary (Albert, 1997).
o
£
197?
1980
1990
20o8'°
Figure 7-3
Long-term trends in mean,
10th, and 90th percentile
streamflow in summer
(July-September) for the
Delaware River at Trenton,
NJ (USGS Gage
01463500).
Source: USGS, 1999.
90%ile
mean & ratio
Figure 7-4
Monthly trends of mean,
10th, and 90th percentile
streamflow for the
Delaware River at Trenton,
NJ (USGS Gage
01463500), 1951-1980.
Source: USGS, 1999.
ONDJFMAMJJAS
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The Delaware River-Delaware Bay system is one of the major coastal plain
estuaries of the east coast of the United States. The tidal river and estuary extend
a distance of 134 miles from the fall line at Trenton, New Jersey, to the ocean
mouth of Delaware Bay along an 11-mile section from Cape May, New Jersey, to
Cape Henlopen, Delaware (Figure 7-1). Because Philadelphia is a major east
coast port, a navigation channel is maintained to a depth of 12 meters (39 feet)
from the entrance to the bay upstream to Philadelphia. From Philadelphia to
Trenton, the channel is maintained at a depth of 8 meters (26 feet) (Galperin and
Mellor, 1990). The semidiurnal tide has a mean range of 1.5 meters (4.9 feet) at
the mouth of the bay and propagates upstream on the incoming tide to Trenton in
approximately 7 hours; typical tidal currents are approximately 1.5 meter sec"'
(Galperin and Mellor, 1990). Approximately 25 miles downstream from Philadel-
phia, tidal currents near the Tacony-Palmyra Bridge (RM 107) are characterized
by vigorous vertical mixing and a marked current reversal with currents of
approximately 1.0 meter sec"1 (Thomann and Mueller, 1987).
The Delaware estuary can be characterized as three distinct hydrographic
regimes based on distributions of salinity, turbidity, and biological productivity:
(1) tidal freshwater, (2) transition zone, and (3) Delaware Bay zone. The tidal
fresh river extends about 55 miles from the head of tide at Trenton, New Jersey
(RM 134) to Marcus Hook, Pennsylvania (RM 79). Under mean freshwater flow
conditions, salinity intrusion in the tidal fresh section of the river generally extends
upstream to the reach between the Delaware Memorial Bridge at Wilmington
(RM 68.7) and Marcus Hook (RM 79.1). During drought periods (e.g., 1962-
1966), salinity intrusion is a concern because industrial water withdrawals are less
desirable and recharge areas of the South Jersey aquifers serving the Camden
metropolitan area are potentially threatened (DRBC, 1992). During drought
conditions, the Delaware River Basin Commission requires releases from the
upper basin reservoirs to prevent critical salinity concentrations from intruding
farther upstream than Philadelphia at RM 98 (DRBC, 1992). The transition zone,
extending about 26 miles from Marcus Hook (RM 79) to Artificial Island, New
Jersey (RM 53), is characterized by low salinity levels, high turbidity, and rela-
tively low biological production (Marino et al., 1991). The estuarine region extends
downstream of Artificial Island about 53 miles to the mouth of Lower Delaware
Bay; salinity in this region varies from approximately 8 ppt upstream to approxi-
mately 28 ppt at the mouth of the bay (Marino et al., 1991).
Population, Water, and Land Use Trends
Four densely populated metropolitan areas have developed along a 50-mile
industrialized section of the Delaware River from Philadelphia, Pennsylvania, and
Trenton and Camden, New Jersey, to Wilmington, Delaware. From 1880 to 1980,
urban growth accounted for most of the 236 percent increase in total population
of the region. The urban proportion of the population increased from approxi-
mately 64 percent at the turn of the century to approximately 80 percent in 1980
(Marino et al., 1991). During the period after World War II from 1950 through
1980, development in the region was characterized by urban and suburban sprawl:
urban land use area increased from 460 square miles in 1950 to 3,682 square
miles by 1980 while population density declined from 8,000 to 3,682 persons per
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Chapter 7: Delaware Estuary Case Study
square mile (Marino et al., 1991). Much of this development occurred by convert-
ing agricultural lands in close proximity to the major metropolitan areas to subur-
ban land uses.
The Delaware River case study area includes 14 counties identified by the
Office of Management and Budget (1995) as the Philadelphia-Wilmington-
Atlantic City, PA-NJ-DE-MD Metropolitan Statistical Area (CMSA) (Table 7-1).
Long-term population trends from 1940 through 1996 for these counties are
presented in Figure 7-5. Population in these counties has increased by 162 percent
from 3.67 million in 1940 to 5.97 million by 1996 (Foretell, 1995;USDOC, 1998).
The city of Philadelphia withdraws water for domestic water supply at the
Torresdale intake upstream of the salt front. The city of Trenton also withdraws
water for public water supply from the Delaware River. In addition to these cities,
Camden, the Delaware County Sewer Authority, and Wilmington are among more
than 80 dischargers of municipal wastewater directly to the estuary or the tidal
portions of its tributaries. Historical water use data are not readily available at the
county level of aggregation to assess the contribution of the Delaware estuary
Table 7-1. Metropolitan Statistical Area (MSA) counties in the Delaware Estuary
case study. Source: OMB, 1999.
Philadelphia-Wilmington-
Atlantic City, PA-NJ-DE-
MD CMS A
Atlantic, NJ
Cape May, NJ
Burlington, NJ
Camden, NJ
Gloucester, NJ
Salem, NJ
Bucks, PA
Chester, PA
Delaware, PA
Montgomery, PA
Philadelphia, PA
Cumberland, NJ
New Castle, DE
Cecil, MD
Figure 7-5
Long-term trends in
population for the
Philadelphia-Wilmington-
Atlantic City MSA counties
of the Lower Delaware
River-Delaware Bay.
Source: Forstall, 1995;
USDOC, 1998.
1940 1950 1960 1970 1980 1990 1996
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
region. However, long-term trends for municipal and industrial water withdrawals
have been compiled by the USGS for the entire Middle-Atlantic Basin from 1950
to 1995 (e.g., Solley et al., 1998). The natural resources (plankton, fisheries,
marshes, and shorebirds), human uses (waste disposal, transportation and dredg-
ing, beach development), and management issues of the Delaware estuary are
presented in Bryant and Pennock (1988).
Historical Water Quality Issues
In reports sent back to Europe, Captain Thomas Young, one of the early
explorers of the Delaware estuary, noted that "the river ctboundeth with bea-
vers, otters and other meaner furrs . . . I think few rivers of America have
more . . . the quantity offowle is so great as hardly can be believed. Offish
heere is plentie, but especially sturgeon. " Early colonial advertising copy like
this, circulated widely in Europe, presumably inspired Old World colonists to
emigrate to the Delaware Valley (Sage and Pilling, 1988). The estuary was
abundant with striped bass, sturgeon, shad, oysters, and waterfowl.
Beginning with the Industrial Revolution and the development of the Dela-
ware Valley as a major industrial and manufacturing center in the 19th century,
waste disposal from increasing population and industrial activities resulted in
progressive degradation of water quality and loss of the once-abundant natural
resources of the estuary. By the turn of the century, the American shad popula-
tion had collapsed. By 1912-1914, low DO conditions were all too common in the
Philadelphia and Camden area of the river (Albert, 1997). Sanitary surveys
conducted in 1929 and 1937 documented poor water quality conditions in the
nontidal reaches of the Delaware from Port Jervis, New York, to Easton, Penn-
sylvania. During high-flow conditions, black water from the Lehigh River-Easton
area would result in closing of the water supply intakes at Trenton, New Jersey
(Albert, 1982).
In the tidal river between Trenton and Philadelphia, the discharge of raw
sewage from Philadelphia, Trenton, Camden, Wilmington, and other communities,
along with untreated industrial wastewater discharges, resulted in gross water
pollution of the estuary. Peak densities of approximately 6,000-8,000 MPN/100
mL were recorded during the late 1960s and early 1970s in the vicinity of the
Philadelphia Navy Yard (RM 90) (Patrick et al., 1992; Marino et al., 1991). Fecal
coliform bacteria levels were high as a result of raw or inadequately treated
wastewater discharges from the large municipalities. Acidic conditions from
industrial waste discharges were observed in the river near the Pennsylvania-
Delaware border; pH levels ranged from approximately 6.5 to 7.0 during 1968-
1970 in the section of the river from Paulsboro (RM 89) to the Delaware Memo-
rial Bridge (RM 68) (Marino et al., 1991). During the summer months in the
1940s, 1950s, and 1960s, DO levels were typically approximately 1 mg/L or less
over a 20-mile section of the river from the Ben Franklin Bridge in Philadelphia
(RM 100) to Marcus Hook (RM 79). Under these anoxic and hypoxic conditions,
the urban-industrial river ran black, and the foul stench of hydrogen sulfide gas
was a common characteristic (Patrick, 1988). Dock workers and sailors were
often overcome by the stench of the river near Philadelphia, and ships suffered
corrosion damage to their hulls from the polluted waters. Aircraft pilots landing in
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Chapter 7: Delaware Estuary Case Study
Philadelphia reported smelling the Delaware estuary at an altitude of 5,000 feet.
Water quality conditions were so bad that President Roosevelt ordered a study in
1941 to determine whether water pollution in the river was affecting the U.S.
defense buildup (Albert, 1982; CEQ, 1982).
Legislative and Regulatory History
Water pollution in the Delaware reached its peak in the 1940s. The source
of the pollution was raw sewage (350 mgd from Philadelphia alone), along with
untreated industrial wastewater of all kinds. In response to steadily increasing
pollution, the Interstate Commission on the Delaware River Basin (INCODEL)
launched a basinwide water pollution control program in the late 1930s. Following
a delay due to the war, the abatement program was finally completed by the end
of the 1950s. During that time the number of communities with adequate sewage
collection and treatment facilities rose from 63 (approximately 20 percent) to 236
(75 percent) (Albert, 1982). Concurrent success was not achieved in abating
industrial pollution.
The first generation of water pollution control efforts, largely completed by
1960, resulted in secondary treatment levels at most treatment plants above
Philadelphia. Primary treatment was considered adequate in the estuary below
Philadelphia. Although most areas built the required facilities, some treatment
facilities from the first-generation effort were not completed until the 1960s or
1970s.
In 1961 INCODEL became incorporated into a more powerful interstate
regulatory agency, the Delaware River Basin Commission (DRBC). The DRBC,
created as a result of federal and state legislation, has broad water resources
responsibilities, including water pollution control. The Commission developed a
clean-up program based on a 6-year $1.2 million Delaware Estuary Comprehen-
sive Study (DECS) conducted by the U.S. Public Health Service. Nearly 100
municipalities and industries were found to be discharging harmful amounts of
waste into the river. The DRBC calculated the river's natural ability to assimilate
oxidizable wastewater loads and established allocations for each city and industry
(Thomann, 1963; Thomann and Mueller, 1987). The objective of the DRBC
wasteload allocation program and the corollary programs of Pennsylvania, New
Jersey, Delaware, and the federal government was to upgrade the somewhat
improved water quality of 1960 to more acceptable levels.
For the purposes of water quality management, the Delaware estuary has
been divided into six water quality zones. Zone 1 is above the fall line at Trenton,
New Jersey. Zones 2 through 6 are in the tidal Delaware, which is water quality-
limited. Here, more stringent effluent limits are required, based on allocations of
assimilative capacity, to achieve water quality standards. Based on the DECS
model, the DRBC in 1967 adopted new, higher water quality standards and then in
1968 issued wasteload allocations to approximately 90 dischargers to the estuary.
These required treatment levels were more stringent than secondary treatment as
defined by EPA in the 1972 Clean Water Act.
7-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
The Delaware River from Trenton, New Jersey, to Listen Point is one of the
most heavily industrialized sections of a waterway in the United States. Four
major cities and a large number of oil refineries and chemical manufacturing
plants are located along the river. The effect of the DRBC wasteload allocation
program and the related water pollution control programs of Pennsylvania, New
Jersey, Delaware, and the federal government on the Delaware Estuary is best
demonstrated by the substantial reduction of ultimate CBOD loading from munici-
pal and industrial dischargers that has been achieved since the late 1950s (Figure
7-6). Ultimate CBOD loadings to the estuary have been reduced by 89 percent
from 1,136,000 Ib/day in 195 8 (Patrick etal., 1992) to 128,277 Ib/day by 1995
(HydroQual, 1998). Major wastewater treatment facilities that upgraded to
secondary treatment and better to meet the wasteload allocations include Phila-
delphia NE (1985), Philadelphia SE (1986), Philadelphia SW (1980), CCMUA
(1989), Trenton (1982), Bordentown MUA (1991), and Lower Bucks MA (1980).
A complete listing of the 34 municipal and 26 industrial point sources discharging
to the Delaware estuary between Trenton and Liston Point is presented by
HydroQual (1998). In addition to reductions of pollutant loading from direct
dischargers to the estuary, the cleanup of major tributaries to the Delaware has
also contributed to water quality improvements in the Delaware estuary (Albert,
1982).
Since implementation of the 1972 CWA, reductions in point source loads of
oxidizable materials have been achieved as a result of technology- and water
quality-based effluent controls on municipal and industrial dischargers in the
Delaware River watershed. Nonpoint source runoff, driven by the land uses and
hydrologic characteristics of the watershed, also contributes a pollutant load that
must be considered in a complete evaluation of the impact of regulatory policy
and controls on long-term water quality trends. To evaluate the relative signifi-
Figure 7-6
Long-term trends in
ultimate CBOD loading
from municipal and
industrial wastewater
dischargers to the
Delaware estuary.
Sources: HydroQual, 1998;
Patrick et al, 1992.
_Q
I
B
a
D' -
O
0.0-
1
III
1940 1950 1960 1970 1980 1990 2000
Municipal | | Industrial
7-8
-------
Chapter 7: Delaware Estuary Case Study
cance of point and nonpoint source pollutant loads, inventories of NPDES point
source dischargers, land uses, and land use-dependent export coefficients
(Bondelid et al., 1999) have been used to estimate catalog unit-based point source
(municipal, industrial, and CSOs) and nonpoint source (rural and urban)1 loads of
BOD5 for mid-1990s conditions in the catalog units of the Delaware River case
study area (see Figure 7-2). The point source load of 105.4 metric tons/day
accounts for 89 percent of the total estimated BOD5 load of 117.1 metric tons/day
from point and nonpoint sources. Municipal facilities contribute 57.3 metric tons/
day (49 percent) while industrial dischargers account for 47.5 metric tons/day (40
percent) of the total point and nonpoint source BOD5 load (Figure 7-7). Nonpoint
sources of BOD5 account for 12.6 metric tons/day; rural runoff contributes
approximately 8 percent and urban land uses account for approximately 5 percent
of the total point and nonpoint load of 117.1 metric tons/day (Figure 7-7).
One of the major trends indicative of water quality improvement in the
estuary has been that for DO. A comparison of mean summer DO levels be-
tween 1968-1972,1975-1979,1981-1985, and 1988-1994 (Figure 7-8) clearly
shows the water quality improvements achieved as a result of the point source
loading reductions of ultimate BOD5 (Figure 7-6). Mean summer DO concentra-
tions have increased by approximately 1 mg/L between River Mile 110 and River
Mile 55 (DRBC Zones 3, 4, and 5) between 1957-1961 and 1981-1985 (Brezina,
1988). DO concentrations have increased from less than 2 mg/L to 5 mg/L at the
critical DO sag point at the mouth of the Schuylkill River in Philadelphia (RM 92)
during the period from 1968-1972 to 1988-1994. DO concentrations increased
steadily farther downstream of Philadelphia (RM 83), reaching a level of approxi-
mately 5.5 mg/L during 1988-1994.
The historical summer DO spatial transects data (Figure 7-8) show that
wastewater discharges from the Philadelphia area result in minimum DO condi-
tions between the Ben Franklin Bridge (RM 100), the Philadelphia Navy Yard
(RM 93), and Marcus Hook (RM 78). Figure 7-9 shows long-term summer (July-
URBAN-NPs4%
cso|i%
IND:MAJ+MIN
MUNICIPAL
Figure 7-7
Point and nonpoint source
loads of BOD5 (ca. 1995)
for the Lower Delaware
River-Delaware Bay case
study area.
Source: Bondelid et al.,
1999.
25 50
BODS Load (metric tons/day)
75
1 For purposes of this comparison, urban stormwater runoff includes areas both outside (termed
"nonpoint sources") and within (which meet the legal definition of a point source in section
502(14) of the CWA) the NPDES stormwater permit program.
7-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 7-8
Long-term trends of the
spatial distribution of
summer DO in the
Delaware estuary.
Source: Patrick et a/.,
1992; Scally, 1997.
-150 -125 -100 -75 -50 -25
River Miles from Cape May-Cape Henlopen
September) trends in DO measured at stations within the reach from the Ben
Franklin Bridge to the Philadelphia Navy Yard. The long-term trend documents
improvements in oxygen during the 1980s and 1990s from the water pollution
control efforts initiated during the 1970s. Most dramatic, however, is the progres-
sive improvement in the minimum oxygen levels during the 1980s and early 1990s.
Summer minimum values increased from approximately 1 mg/L or less in the
1960s and 1970s to approximately 4-5 mg/L during 1990-1995. Although oxygen
conditions improved tremendously between the 1960s and the early 1990s, a
continued trend of further improvements during the 1990s has not been recorded.
Minimum oxygen concentrations still can approach 4 mg/L near Chester, Pennsyl-
vania (River Mile 84) and can drop lower than 4 mg/L in the 10-mile oxygen sag
reach between River Mile 95 and River Mile 85 (HydroQual, 1998).
Spatial water quality trends recorded during the late 1960s, 1970s, 1980s,
and 1990s include documentation of temporal declines in BOD5 (Figure 7-10),
ammonia-N (Figure 7-11), total nitrogen (Figure 7-12), and total phosphorus
(Figure 7-13). Effluent reductions of oxygen-demanding loads from industrial and
Figure 7-9
Long-term trends of
summer (July-September)
DO in the Delaware
estuary near Philadelphia,
PA (RF1-02040202030,
mile 100-80).
Source: USEPA (STORET).
T940
1950
1960 1970 1980 1990 2000
Philadelphia PA [River Mile 100-80]
Mean Mm Max
7-10
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Chapter 7: Delaware Estuary Case Study
8005
("19/0
6
5
4
3
2
1
o-l
40
YEAR
80 100 120 MO 160 180 200 220
River Kilometer
1968-1970 1978-1980 1988-1990
Figure 7-10
Long-term trends of the
spatial distribution of BOD5
in the Delaware estuary
(mean of data from 1968-
1970, 1978-1980, and
1988-1990).
Source: Marino et al., 1991.
NH3-N
(mg/i)
1.6
1,5
1,4
1.3
1.2
l.l-
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0
1
o.o-
1—
40
—1—
60
—I—
80
—I—
100
YEAR
1968-1970
' 1 ' 1 ' 1 •
120 140 160
River Kilometer
1978-1980
—1 . 1 , 1-
180 200 220
1988-1990
Figure 7-11
Long-term trends of the
spatial distribution of
ammonia-nitrogen in the
Delaware estuary (mean of
data from 1968-1970,
1978-1980, and 1988-
1990).
Source: Marino et al., 1991.
To». N
(mg/l)
5
3
2'
1
Oi
40 60 80 100 120 140 160 180 200 220
River Kilometer
YEAR 1968-1970 1978-1980 1988-1990
Figure 7-12
Long-term trends of the
spatial distribution of total
nitrogen in the Delaware
estuary (mean of data from
1968-1970, 1978-1980,
and 1988-1990).
Source: Marino et al., 1991.
7-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 7-13
Long-term trends of the
spatial distribution of total
phosphorus in the
Delaware estuary (mean of
data from 1968-1970,
1978-1980, and 1988-
1990).
Source: Marino et a/., 1991.
TPhos
0.50
0.45
0.40
0.35'
0.30
0.25
0.20
0.15H
0.10
0.05
0.00
40 60 80 100 120 140 160 180 200 220
River Kilometer
1968-1970 1978-1980 1988-1990
municipal sources have resulted in significant declines in ambient levels of BOD5
and ammonia-N. An interannual temporal trend for ambient ammonia-N (Figure
7-14) at a station near Marcus Hook (RM 78) shows a considerable improvement
in water quality, with a steep decline from approximately 1.4 mg N/L during the
late 1960s to approximately 0.5 mg N/L by the late 1970s, followed by relatively
unchanging ambient concentrations (approximately 0.15 mg N/L) recorded during
the mid-1980s through the mid-1990s (Santoro, 1998). The decline in ambient
ammonia-N during this 30-year period has been shown to correspond to a concur-
rent increase in nitrate-N from the mid-1970s through the mid-1980s as a result of
nitrification (Santoro, 1998; Marino et al., 1991). Reflecting deforestation, agricul-
tural practices, fossil fuel combustion, and the increase in human population of an
increasingly urbanized drainage basin over the much longer time scale of a
century, ambient nitrate and chloride levels (Figure 7-15) have steadily increased
by approximately 400 percent to 500 percent since measurements were first
recorded in 1905 at a water supply intake near Philadelphia (Jaworksi and
Hetling, 1996). Similar patterns of long-term increasing trends in ambient nitrate
Figure 7-14
Long-term trends of
summer ammonium-N
and total phosphorus at a
station in the Delaware
estuary near Marcus Hook
(mile 78) (computed as 4-
year moving averages for
July from DRBC boat run
records).
Source: Santoro, 1998.
1965 1970 1975 1980 1985 1990 1995 2000
7-12
-------
Chapter 7: Delaware Estuary Case Study
-Chlorides-
-N03
32.0
1.60
1.40
0.0
0.00
Years
and chlorides have also been recorded at other east coast water supply intakes
for the Merrimack, Connecticut, Hudson, Schuykill, and Potomac rivers (Jaworksi
and Hetling, 1996). Total phosphorus has also declined from peak levels of
approximately 0.45 mg P/L during 1968-1970 to much lower levels of approxi-
mately 0.15 mg P/L by 1988-1990 near River Mile 100 (Figure 7-13). An
interannual time series of total phosphorus (Figure 7-14) for a station near Marcus
Hook (River Mile 78) exhibits a trend similar to that of ammonia-N with a sharp
decline from approximately 0.8 mg P/L in the late 1960s to approximately 0.3 mg
P/L by the late 1970s, followed by relatively unchanging concentrations (approxi-
mately 0.1 mg P/L) from the mid-1980s through the mid-1990s. The decline of
ambient levels of total phosphorus has been attributed to the detergent phosphate
ban of the early 1970s (Jaworski, 1997), reductions of effluent loads from waste-
water facility upgrades (Sharp, 1988), and changes in partitioning of dissolved and
soluble phases of phosphorus and changes in solubility of phosphate (Lebo and
Sharp, 1993).
Evaluation of Water Quality Benefits
Following Treatment Plant Upgrade
From a policy and planning perspective, the central question related to the
effectiveness of the secondary treatment requirement of the 1972 CWA is simply
Would water quality standards for DO be attained if primary treatment levels
were considered acceptable? In addition to the qualitative assessment of
historical data, water quality models can provide a quantitative approach to
evaluate improvements in DO and other water quality parameters achieved as a
result of upgrades in wastewater treatment. Since the early 1960s, four classes of
water quality models, developed from the 1960s, through the 1990s, have been
applied to determine waste load allocations for municipal and industrial discharg-
ers to meet the needs for water quality management decisions for the Delaware
estuary (Mooney et al., 1998).
Figure 7-15
Long-term trends of
chlorides and nitrate-N at a
water supply intake in the
tidal Delaware River near
Philadelphia.
Source: Jaworski and
Hetling, 1996; Jaworski,
1997.
7-13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
During the 1960s, one-dimensional estuarine water quality models of DO
and carbonaceous and nitrogenous BOD were developed by Thomann (1963),
O'Connor et al., (1968), Pence et al. (1968), Jeglic and Pence (1968), and Feigner
and Harris (1970). DRBC used a 1960s era model, known as the Delaware
Estuary Comprehensive Study (DECS) model, to establish waste load allocations
for ultimate CBOD and nitrogenous BOD for the six zones of the Delaware.
With funding available from the CWA Section 208 program during the 1970s,
Clark et al. (1978) upgraded the kinetics of the water quality model to incorporate
nitrification and denitrification in a nitrogen cycle represented by organic nitrogen,
ammonia, and nitrate+nitrite as state variables. The oxygen contribution by algal
production and respiration was included as an empirical input term dependent on
chlorophyll observations. Transport was provided to the water quality model with
one-dimensional link-node hydrodynamics, and the 1970s-era model was identified
as the Dynamic Estuary Model (DEM) (Mooney et al., 1998).
As a result of industrial and municipal waste treatment plant upgrades from
primary to secondary levels of treatment during the late 1970s and early 1980s,
the water quality model used for waste load allocations was once again upgraded
to reflect the reduced waste loads and improvements in water quality conditions
(Mooney et al., 1998). The model was upgraded from a one-dimensional (longitu-
dinal) to a two-dimensional representation (longitudinal and lateral) variation of
water quality and transport in the Delaware estuary. A two-dimensional hydrody-
namic model was coupled with a water quality model that retained the kinetic
framework of the one-dimensional model with kinetic coefficients adjusted to
reflect changes in pollutant loading (LTI, 1985). The upgraded 1980s-era two-
dimensional model (DEM-2D) was used to conduct a toxics analysis (Ambrose,
1987) and to reevaluate the waste load allocations developed with the earlier
models (DRBC, 1987).
Following the completion of the Delaware Estuary Use Attainability (DEL
USA) Project (DRBC, 1989), a technical review of the two-dimensional DEM
model recommended that a new time-variable model be developed to incorporate
state-of-the-art advances, with a three-dimensional hydrodynamic model coupled
to an advanced eutrophication model framework (HydroQual, 1994). Using
revised kinetic coefficients to reflect reductions in waste loads and improvements
in water quality, the kinetics of the water quality framework were expanded to
include a eutrophication submodel, nitrogen and phosphorus cycles, labile and
refractory organic carbon, and particulate and dissolved fractions of organic
carbon and nutrients (HydroQual, 1998; Mooney et al., 1999). Unlike the
eutrophication model developed for the Chesapeake Bay (Cerco and Cole, 1993),
internal coupling of particulate organic matter's deposition with sediment oxygen
demand and benthic nutrient fluxes was not included in the upgraded framework;
benthic fluxes were assigned as model input on the basis of monitoring data
(HydroQual, 1998).
To evaluate the incremental improvements in water quality conditions that
can be achieved by upgrading municipal wastewater facilities from primary to
secondary and better-than-secondary levels of waste treatment, Lung (1991) used
the 1970s-era one-dimensional DEM model (Clark et al., 1978) to demonstrate
the water quality benefits attained by the secondary treatment requirements of the
1972 CWA. Using the model, Lung used existing population and municipal and
industrial wastewater flow and effluent loading data (ca. 1976) to compare water
7-14
-------
Chapter 7: Delaware Estuary Case Study
quality for summer flow conditions simulated with three management scenarios
for municipal facilities: (1) primary effluent, (2) secondary effluent, and (3)
existing wastewater loading. Water quality conditions for these alternatives were
calibrated (Figure 7-16) using data for 1976, a year characterized by average
summer flow of the Delaware River (see Figure 7-3). Freshwater flow at Tren-
ton, New Jersey, was 7,700 cfs; flow in the Schuykill River, a major tributary to
the Delaware estuary, was 1350 cfs for the 1976 calibration. Flow conditions
during the summer of 1976 were 120 percent higher than the long-term (1951-
1980) summer (July-September) mean streamflow of 5,986 cfs recorded at
Trenton. Upstream of Trenton, flow releases from several impoundments along
the free-flowing Delaware River are regulated to maintain the guideline for a
minimum summer streamflow of 2,500 to 3,000 cfs at Trenton (Mooney et al.,
1998).
(a)
(b)
(C)
(d)
140 130 120 110 100 90 80 70 60 50 4-0
140 130 120 110 100 90 80 70 60 50 40
140 130 120 110 100 90 80 70 60 50 40
10
< 8
£ 6
X-**
§ *
140 130 120 110 100 90 80 70 60 50 40
River Miles from Mouth
Legend: $ Observed Data (Avg. and Range) Model Results
Figure 7-16
Model vs. data comparison
for calibration of the 1 -D
Dynamic Estuary Model
(DEM) for the Delaware
estuary to July 1976
conditions for:
(a) ammonia, (b) nitrate,
(c) CBOD5, and (d) DO.
Source: Lung, 1991.
7-15
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Under the primary effluent assumption, water quality is noticeably deterio-
rated in comparison to the 1976 calibration results. DO concentrations are at a
minimum about 35 miles downstream of Trenton, the traditional region of mini-
mum DO levels. Under the primary scenario, an oxygen sag of 2 mg/L is com-
puted by the model under summer (28EC), low-flow 7Q10 conditions (2,500 cfs
for the Delaware at Trenton and 285 cfs for the Schuykill River at Philadelphia)
(Figure 7-17).
Using the secondary effluent assumption, the reduction in ultimate CBOD
loading significantly improves DO downstream of Philadelphia at the critical
oxygen sag location (RM 96). In comparison to the primary scenario, minimum
oxygen levels increased to almost 4 mg/L from approximately 2 mg/L under the
Figure 7-17
Comparison of simulated
water quality impact of
primary, secondary, and
existing (1976) wastewater
loading conditions on
(a) ammonia, (b) nitrate,
(c) CBOD5, and (d) DO in
the Delaware Estuary, July
1976 conditions.
Source: Lung, 1991.
(a)
(b)
(c)
(d)
3.0
O2.5
|"2.0
Vt5
11.0
10.5
0.0
J>.0
£2.0
l_
•+->
21.0
0.0
10
8
140 130 120 110 100 90 80 70 60 50 40
5.0
140 130 120 110 100 90 80 70 60 50 40
HO 130 120 110 100 90 80 70 60 50 40
140 130 120 110 100 90 80 70 60 50 40
River Miles from Mouth
Legend: Primary Treatment Secondary Treatment 1976 Loads
7-16
-------
Chapter 7: Delaware Estuary Case Study
10
5-
2.0
Primary Secondary Existing 1976
Municipal Effluent Scenario
Figure 7-18
Model simulation of DO
under July 1976 "normal"
streamflow conditions at
the critical oxygen sag
location (mile 96) in the
Delaware estuary for
primary, secondary and
existing (1976) effluent
loading scenarios.
Source: Lung, 1991.
secondary effluent scenario (Figure 7-18). To achieve compliance with a water
quality standard of 5 mg/L, advanced waste treatment is required (Albert, 1997).
As shown with the historical water quality data sets, the implementation of
secondary and better-than-secondary levels of wastewater treatment has resulted
in major improvements in the DO, BOD5, ammonia, and total phosphorus of the
estuary (Figures 7-8 through 7-14). As demonstrated with the model, better-than-
secondary treatment is required to achieve compliance with the water quality
standard of 5 mg/L for DO downstream of Philadelphia. In contrast to the 1950s
and 1960s, the historical occurrence of persistent and extreme low DO conditions
has essentially been eliminated from the upper Delaware estuary. Improvements
in suspended solids, heavy metals, and fecal coliform bacteria levels have also
been achieved as a result of upgrades in municipal and industrial wastewater
treatment.
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
With vast tidal marshes and freshwater tributaries providing spawning and
nursery grounds for abundant fishery resources, the coastal plain of the Delaware
estuary provided a cornucopia of fishery and waterfowl resources important for
sustenance to both Native American villages and colonial settlements. Historically,
the estuary produced an enormous quantity of seafood from the early colonial era
(ca. 1700s) through the early 20th century. Colonial reports suggest schools of
herring and sheepshead thick enough to walk on in a stream (Price et al., 1988).
Rich harvests of American shad and shortnose sturgeon provided important
sustenance to the growing population of the Delaware valley for about 200 years.
Since the mid-1900s, however, the abundance of these, and other, species
has declined dramatically as a result of urbanization and industrialization of the
drainage basin. Deterioration in water quality (e.g., severe oxygen depletion),
7-17
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
overfishing, construction of dams, and habitat destruction have all contributed to
the decline of the river's fisheries resources beginning around the turn of the
century (Majumdar et al, 1988). Massive fish kills were a frequent occurrence
along the river from about 1900 through 1970 (Albert, 1988). Former wetlands
and tributaries, critical to the spawning success of anadromous species, have been
converted into docks, wharves, industrial sites, and oil refineries (Stutz, 1992).
Decades of discharge of untreated municipal and industrial waste resulted in
severe declines in the once-abundant fishery resources of the Delaware estuary.
In 1836 commercial landings of the American shad (Alosa sapidissima), an
important anadromous fish that spawns in the Upper Delaware River, were
estimated at 10.5 million pounds. By the turn of the century, the average annual
harvest of shad was 12-14 million pounds (Frithsen et al., 1991). Historically, the
commercial shad harvest from the Delaware River fishery was the largest of any
river system along the Atlantic coast (Frithsen et al., 1991). Primarily as a
consequence of overfishing, water pollution and low levels of DO that created a
"dead zone," construction of dams, and other obstructions in the river, shad
populations declined drastically in the early 1900s (Frithsen et al., 1991).
In a pattern similar to that for shad, annual commercial landings of striped
bass (Morone saxatilis) have also dropped from hundreds of thousands of
pounds per year in the early 1900s to only thousands of pounds per year by 1960.
In 1969 a fishery survey showed a complete absence of striped bass larvae and
eggs along the Philadelphia-Camden waterfront, which had been an important
spawning and nursery area for striped bass; by 1980 there was no commercial
catch of striped bass (Himchak, 1984).
The historical abundance of shortnose sturgeon (Acipenser brevirostrum),
once prized for caviar that rivaled imported Russian caviar, also followed the
same precipitous decline as shad as overfishing and water pollution took their toll
on this once-thriving fishery. Historically, the range of the shortnose sturgeon was
from the lower Delaware Bay as far upstream as New Hope, Pennsylvania (RM
149) (Frithsen et al., 1991). Historical records from 1811 to 1913 document 1,949
sturgeon captured, primarily as a bycatch of the shad gill net fishery. During the
period from 1913 through 1954, no documented catches of sturgeon were re-
ported. From 1954 through 1979, 37 sturgeon were reported in fishery and
ecological surveys. From 1981 to 1984, 1,371 sturgeon were collected between
Philadelphia and Trenton (Frithsen et al., 1991). Using data collected from the
early 1980s surveys, Hastings et al. (1987) have estimated populations of approxi-
mately 6,000 to 14,000 adult shortnose sturgeon in the upper tidal river near
Trenton, with a smaller population estimated for the section of the river near
Philadelphia (Frithsen et al., 1991).
Although it is difficult to assess the relative importance to these species of
each of the major industrialization factors that contributed to the declines, Sum-
mers and Rose (1987) identified a connection between water quality, especially
DO concentrations, and wastewater loading and shad population levels. Using
records collected during the 20th century from the Delaware, Potomac, and
Hudson estuaries, historical fluctuations in American shad populations have been
strongly correlated with wastewater discharges that increased biochemical
oxygen demand levels and depleted oxygen resources (Summers and Rose,
1987). Albert (1988) and Sharp and Kraeuter (1989) also noted the importance of
good oxygen concentrations to successful shad migrations. Little correlation
7-18
-------
Chapter 7: Delaware Estuary Case Study
between water quality and striped bass populations was found, but Summers and
Rose (1987) noted that larval survival for both shad and striped bass is tied to DO
and other water quality factors.
Beginning in the mid- 1970s, however, the water pollution control efforts of
the 1970s and 1980s have paid off with a dramatic recovery of once moribund
fishery resources. Estimates of the American shad population fluctuated from a
low of 106,202 in 1977 to a high of 882,600 in 1992 (Santoro, 1998) (Figure 7-19).
As a result of improvements in water quality conditions, the spawning area used
by shad has increased by 100 miles in the estuary (Albert, 1997). Annual shad
festivals are now celebrated in the spring along the Delaware River, and the
recreational shad fishery is considered to be a multimillion-dollar industry (Frithsen
et al., 1991). As a result of water pollution control efforts and a well-regulated
fishery, populations of striped bass in the Delaware River are also showing
evidence of a resurgence of once-depleted populations (Santoro, 1998). Assess-
ments of commercial harvest statistics for American shad (Figure 7-20), striped
I.UV
^ n -7CL
n Method)(n
3 C
?....?
ion (Peterse
3 C
*. . . .8:
£
nnn.
ihlil
1
Figure 7-19
Long-term trends in
population estimates of
adult American shad in the
Delaware estuary.
Source: Santoro, 1998.
1975 ' ' ' i960
i98'5 ' ' ' 1990 ' ' ' 1'995
Figure 7-20
Trends in catch efficiency
for American shad in the
Delaware estuary.
Source: Weisberg et al.,
1996.
1980
1985
1990
1995
7-19
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
bass (Figure 7-21), and white perch (Figure 7-22) clearly document significant
increases in the catch-per-unit effort of these species from 1985 to 1993, corre-
lated with improvements in water quality (Weisberg et al., 1996). Trends in catch
efficiency are also reported by Weisberg et al. (1996) for blueback herring and
alewives. Studies of the distribution and abundance of the shortnose sturgeon,
listed as an endangered species (Price et al., 1988), suggest that populations may
be recovering from the historical decimation of this species during the 20th
century from water pollution and overfishing (Fristhsen et al., 1991).
In addition to pelagic fishery resources, the Delaware estuary has histori-
cally provided important harvests of American oysters, blue crabs, horseshoe
crabs, hard clams, and American lobsters. Following a pattern identified in New
York Harbor, a sharp decline in the harvest of oysters during the 1950s has been
attributed to overfishing, sediment runoff and industrialization of the watershed,
industrial and municipal wastewater discharges, oil spills, and spraying of marshes
with DDT for mosquito control (Frithsen et al., 1991). In 1957 a parasitic organ-
ism (MSX) infected the oyster beds, drastically reducing abundance for decades.
Figure 7-21
Trends in catch efficiency
for striped bass in the
Delaware estuary.
Source: Weisberg et al.,
1996.
10.0
0.0^
1980
1985
1990
1995
Figure 7-22
Trends in catch efficiency
for white perch in the
Delaware estuary.
Source: Weisberg et al.,
1996.
1985
1990
1995
7-20
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Chapter 7: Delaware Estuary Case Study
o
0)
I
0.0
Figure 7-23
Long-term trends of
commercial blue crab
catch in the Delaware
estuary (New Jersey and
Delaware totals).
Source: Patrick et al.,
1992.
1940
1950
1960
1970
1980
1990
2000
With the decline of the oyster harvest, the blue crab catch has accounted for most
of the shellfish catch of the Delaware estuary. During the late 1800s through the
1930s few blue crabs were harvested commercially. Since the 1930s, commercial
landings have increased substantially, particularly during the 1980s (Figure 7-23),
although large interannual variability in the Delaware estuary is characteristic of
this species sensitive to water temperature (Frithsen et al., 1991). More detailed
reviews of historical trends for the shellfish and fishery resources of the Dela-
ware estuary are given by Price et al. (1988), Patrick (1988), Patrick et al.
(1992), and Frithsen et al. (1991).
Summary and Conclusions
During the 1940s, 1950s and 1960s, the Delaware estuary was character-
ized by severe water quality problems, including the foul stench of hydrogen
sulfide gas caused by anoxic conditions in sections of the river near Philadelphia.
Uncontrolled wastewater discharges and destruction of habitat from urban and
industrial growth in the Delaware watershed were responsible, along with over-
fishing, for the collapse of many historically important fisheries in the Delaware
estuary such as American shad, striped bass, shortnose sturgeon, and American
oysters. Desirable amenities such as parks, walking trails, or cafes along the
riverfront were not considered for urban development because of the noxious
conditions of the Delaware River.
As a result of water pollution control efforts implemented since the late
1960s in the Delaware estuary, dramatic reductions in municipal and industrial
effluent discharges of ultimate CBOD, ammonia-N, total phosphorus, and fecal
coliform bacteria have been achieved by upgrading wastewater treatment facili-
ties to secondary and better-than-secondary levels of treatment. Municipal and
industrial loading of ultimate CBOD to the river, for example, was reduced by 89
percent during the period from 1958 to 1995.
New construction and upgrades of municipal and industrial water pollution
control facilities have resulted in significant improvements in water quality, the
resurgence of important commercial and recreational fishery resources, and a
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
renewal of economic vitality to once abandoned urban waterfronts along the
Delaware River.
Assessment of long-term trends of historical water quality data at critical
locations clearly documents great improvements in DO, ammonia-nitrogen, total
phosphorus, and fecal coliform bacteria. DO, for example, has improved from
typical summer minimum levels of less than 1 mg/L during the 1960s and 1970s
along a 10-mile section of the river downstream from Philadelphia to minimum
levels of 4 mg/L and higher during the 1990s. Ambient ammonia concentrations
near Marcus Hook have declined by an order of magnitude from late 1960s levels
of approximately 1.4 mg N/L to mid-1990s levels of approximately 0.15 mg N/L.
Total phosphorus has exhibited a trend similar to ammonia's with late 1960s levels
of approximately 0.8 mg P/L dropping almost an order of magnitude to approxi-
mately 0.1 mg P/L during the mid-1990s.
A number of indicators of environmental resources of the Delaware estuary
have also demonstrated tremendous improvements that can be attributed to the
water pollution control efforts and associated public awareness of the importance
of environmental quality initiated by the 1972 CWA. The recovery of the Ameri-
can shad population during the mid-1980s, for example, is a remarkable achieve-
ment. The restoration of this important fishery resource to populations that can
support an extensive recreational and commercial fishery is a remarkable success
story. Highly popular annual shad festivals now celebrate the seasonal migration
of this fish from the ocean into the estuary as a rite of spring.
Although the restoration of valuable fishery resources is important from an
economic and ecological perspective, the recreational benefits achieved by the
cleanup of the Delaware River far exceed the benefits attributed to fishery
improvements. Riverfront development for commercial uses and public parks,
increases in sailing and boating, and numerous other economic benefits have
occurred along the Delaware River. Most remarkable is that the city centers of
Philadelphia, Wilmington, and Trenton, after decades of urban development
activity retreating inland, are now moving back toward the riverfront. Investments
in urban development along the river would simply not be feasible without the
aesthetic qualities of clean water (Albert, 1997). Urban waterfront and riverfront
development activity has also been booming in many other cities (e.g., New York
Harbor; Cleveland, Ohio; Boise, Idaho; Portland, Oregon; Atlanta, Georgia;
Richmond, Virginia) that have successfully cleaned up polluted rivers, lakes, and
harbors, making their urban waterways assets and sources of civic pride rather
than disgraceful liabilities.
Despite the remarkable environmental improvements achieved by invest-
ments in water pollution control infrastructure since initiation of the 1972 CWA,
challenges remain for the next generation. Water quality and resource manage-
ment problems recognized only since the mid-1980s must be addressed. Contami-
nation of the water column and sediments by heavy metals such as mercury,
chromium, lead, copper, and zinc has been identified in urban-industrial areas of
the river. Probable sources of heavy metals include natural geochemical pro-
cesses, industrial and municipal dischargers, stormwater runoff, and atmospheric
deposition (Santoro, 1998). Toxic chemicals such as PCBs, PAHs, and pesticides
have also contaminated the water column and sediments of the estuary, resulting
in bioaccumulation in benthic organisms. Fish consumption advisories were issued
in 1989 by New Jersey and Pennsylvania and in 1996 by Delaware (Santoro,
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Chapter 7: Delaware Estuary Case Study
1998). Acute sediment toxicity appears to be more widespread in the estuary than
previously documented, with the highest areas of sediment toxicity identified in the
heavily urbanized and industrialized region between Torresdale and Marcus Hook.
Chronic toxicity was also identified in the water column under particular condi-
tions of streamflow and effluent discharges (Santoro, 1998). The design and
construction of facilities to control and treat combined sewer overflow discharges
of raw sewage to the tidal river during heavy rainstorms is an ongoing project.
Finally, the allocations of wastewater loads for ultimate CBOD from municipal
and industrial dischargers that have evolved since 1968 will need to be revised to
ensure that the water quality improvements achieved since the 1970s can con-
tinue to be maintained as population and industrial activity grow during the 21st
century (Mooney et al., 1999; HydroQual, 1998).
In 1973 a USEPA study concluded that the Delaware River would never
achieve designated uses defined by "fishable standards." More than 25 years
after that pessimistic pronouncement, the fishery resources of the Delaware
estuary are thriving. The restoration of the vitality of the estuary is a direct result
of water pollution control efforts and strong public awareness of the importance
of supporting federal, state, and local environmental regulations and policies.
References
Albert, R.C. 1982. Cleaning up the Delaware River. Status and progress
report prepared under the auspices of Section 305(b) of the Federal Clean
Water Act. Delaware River Basin Commission, West Trenton, NJ.
Albert, R,C. 1988. The historical context of water quality management for the
Delaware estuary. Estuaries 11(2): 99-107.
Albert, R.C. 1997. Delaware River Basin Commission, West Trenton, NJ.
Personal communication, July 31,1997.
Ambrose, R.B. 1987. Modeling volatile organics in the Delaware estuary. Jour.
Environ. Eng. ASCE 113(4): 703-721.
Bondelid, T., C. Griffiths, and G. Van Houten. 1999. A national water pollution
control assessment model. Draft technical report prepared for U.S. Envi-
ronmental Protection Agency, Office of Science & Technology, Washington,
DC, by Research Triangle Institute (RTI), Research Triangle Park, NC.
Brezina, E.R. 1988. Water quality issues in the Delaware River Basin.
In Ecology and restoration of the Delaware River Basin, ed. S.K.
Majumdar, E.W. Miller, and L.E. Sage, pp. 30-38. Pennsylvania Academy of
Science, Philadelphia, PA.
Bryant, T.L., and J.R. Pennock. 1988. The Delaware estuary: Rediscovering
a forgotten resource. University of Delaware Sea Grant College Program,
Newark, DE. Philadelphia Press, Burlington, NJ.
CEQ. 1982. Environmental quality 1982. 13th Annual Report of the Council
on Environmental Quality. Executive Office of the President, Council on
Environmental Quality, Washington, DC.
Cerco, C., and T. Cole. 1993. Three-dimensional eutrophication model of
Chesapeake Bay. Jour. Environ. Eng. ASCE 119(6): 1006-1025.
Clark, L.J., R.B. Ambrose, and R.C. Grain. 1978. A water quality modelling
study of the Delaware Estuary. Technical Report 62. U.S. Environmental
Protection Agency, Region 3, Annapolis Field Office, Annapolis, MD.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
DRBC. 1987. Recalibration/verification of the Dynamic Estuary Model for
current conditions in the Delaware estuary. DEL USA Project Element 19.
Delaware River Basin Commission, West Trenton, NJ.
DRBC. 1989. Delaware estuary use attainability project: Final report. DEL
USA Project. Delaware River Basin Commission, West Trenton, NJ.
DRBC. 1992. Delaware River and Bay water quality assessment 1990-1991
305(b) report. Delaware River Basin Commission, West Trenton, NJ.
Feigner, K. and H.S. Harris. 1970. Documentation report on FWQA Dynamic
Estuary Model. U.S. Department of the Interior. Annapolis, MD.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to 1990.
U.S. Bureau of the Census, Population Division, Washington, DC. .
Frithsen, J.B., K. Killam, and M. Young. 1991. An assessment of key biologi-
cal resources in the Delaware River estuary. Prepared for the Delaware
Estuary Program, U.S. Environmental Protection Agency, Region 2, New
York, NY, by Versar, Inc, Columbia, MD.
Galperin, B., and G.L. Mellor. 1990. A time-dependent, three-dimensional model
of the Delaware Bay and River system. Part 1: Description of the model and
tidal analysis. Est. Coast. Shelf Sci. 31: 231-253.
Hastings, R.W, F.C. O'Herron, II, K. Schick, and M.A. Lazzari. 1987. Occur-
rence and distribution of shortnose sturgeon, Acipenser brevirostrum, in the
upper tidal Delaware River. Estuaries 10(4): 337-341.
Himchak, P.J. 1984. Monitoring of the striped bass population in New
Jersey. Final report covering the period from December 1, 1983, through
September 30, 1984. New Jersey Department of Environmental Protection,
Division of Fish, Game and Wildlife, Bureau of Marine Fisheries.
HydroQual. 1994. Review of the Delaware River DEM Models. Tech. Report
prepared for Delaware River Basin Commission, West Trenton, NJ, by
HydroQual, Inc., Mahwah, NJ.
HydroQual. 1998. Development of a hydrodynamic and water quality model
for the Delaware River. Tech. Report prepared for Delaware River Basin
Commission, West Trenton, NJ. by HydroQual, Inc., Mahwah, NJ. May 29.
Iseri, K.T., and W.B. Langbein. 1974. Large rivers of the United States.
Circular No. 686. U.S. Department of the Interior, U.S. Geological Survey.
Jaworski, N. 1997. Total nitrogen (TN) and phosphorus (TP) loadings and
TN:TP molar ratios for the estuaries of the Middle Atlantic and North-
east U.S.A. during the last century. Estuarine Research Foundation
Conference, 1997.
Jaworski, N., and L. Hetling. 1996. Water quality trends of the Mid-Atlantic and
Northeast watersheds over the past 100 years. In Proceedings Watershed
'96: A National Conference on Watershed Management, pp. 980-983.
Baltimore, MD, June 8-12, 1996. Water Environment Federation, Alexan-
dria, VA.
Jeglic, J.M., and G.D. Pence. 1968. Mathematical simulation of the estuarine
behavior and its application. Socio-Econ. Plan. Sci. 1: 363-389.
Lebo, M.E., and J.H. Sharp. 1993. Distribution of phosphorus along the Dela-
ware, an urbanized coastal plain estuary. Estuaries 16(2): 290-301.
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Chapter 7: Delaware Estuary Case Study
LTI. 1985. Two-dimensional DEM model of the Delaware estuary. Technical
report prepared for Delaware River Basin Commission, West Trenton, NJ,
by LimnoTech, Inc., Ann Arbor, MI.
Lung, W. 1991. Trends in BOD/DO modeling for waste load allocations of
the Delaware River estuary. Tech. Memorandum prepared for Tetra Tech,
Inc., Fairfax, VA, by Enviro-Tech, Inc., Charlottesville, VA.
Majumdar, S.K., E.W. Miller, L.E. Sage (eds.). 1988. Ecology and restoration
of the Delaware River Basin. The Pennsylvania Academy of Science.
Easton, Pennsylvania.
Marino, G.R., J. L. Di Lorenzo, H.S. Litwack, T.O. Najarian, and M.L. Thatcher.
1991. General water quality assessment and trend analysis of the
Delaware Estuary, Part One: Status and trends. Prepared for Delaware
Estuary Program and Delaware River Basin Commission, West Trenton, NJ,
by Najarian & Associates, Eatontown, NJ.
Mooney, K.G., T.W. Gallagher, and H.J. Salas. 1998. A review of thirty years
of water quality modeling of the Delaware estuary. Paper presented at
XXVI Congress Inter Americano de Ingenieria Sanitaria Y Ambiental-
Associacion Inter Americano de Ingenieria Sanitaria Y Ambiental
(AIDIS), November 1-5, 1998, Lima, Peru.
Mooney, K.G., P.J. Webber and T.W. Gallagher. 1999. A new total maximum
daily load (TMDL) model for the Delaware River. Paper presented at
WEFTEC'99, 1999 annual conference of the Water Environment Federation,
New Orleans, LA. Water Environment Federation, Alexandria, VA.
O'Connor, D.J., J.P. St. John, and D.M. Di Toro. 1968. Water quality analysis of
the Delaware River Estuary. J. Sanit. Eng. Div., ASCE 94(SA6):
1225-1252.
OMB. 1999. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
Patrick, R. 1988. Changes in the chemical and biological characteristics of the
Upper Delaware River estuary in response to environmental laws. In:
Ecology and Restoration of the Delaware River Basin, ed. S.K.
Majumdar, E.W. Miller, and L.E. Sage, pp. 332-359. Pennsylvania Academy
of Science, Philadelphia, PA.
Patrick, R., F. Douglass, D.M. Palarage, and P.M. Stewart. 1992. Surface
water quality: Have the laws been successful? Princeton University
Press, Princeton, NJ.
Pence, G.D., J.M. Jeglic, and R.V. Thomann. 1968. Time-varying DO model. J.
Sanit. Eng. Div, ASCE 94(SA4): 381-402.
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Delaware Estuary: Rediscovering a forgotten resource, ed. T.L. Bryant
and J. R. Pennock, pp. 71-93. Univ. Delaware Sea Grant College Program,
Newark, DE. Philadelphia Press, Burlington, NJ.
Sage, L.E., and F.B. Pilling. 1988. The development of a nation: the Delaware
River. Chapter 14 in Ecology and restoration of the Delaware River
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Basin, ed. S.K. Majumdar, E.W. Miller, and L.E. Sage, pp. 217-233. The
Pennsylvania Academy of Science, Philadelphia, PA.
Santoro, E. 1998. Delaware estuary monitoring report. Report prepared for
Delaware Estuary Program, U.S. Environmental Protection Agency, Region
2, New York, NY, by Delaware River Basin Monitoring Coordinator in
cooperation with the Monitoring Implementation Team of the Delaware
Estuary Program.
Scally, P. 1997. Delaware River Basin Commission, West Trenton, NJ. Personal
communication, August 1997.
Sharp, J.H. 1988. Trends in nutrient concentrations in the Delaware Estuary. In
Ecology and restoration of the Delaware River Basin, ed. S.K.
Majumdar, E.W. Miller, and L.E. Sage, pp. 77-92. The Pennsylvania Acad-
emy of Science, Philadelphia, PA.
Sharp, J.H., and J.N. Kraeuter. 1989. The state of the Delaware Estuary.
Summary report of a workshop held on October 19. Scientific and Technical
Advisory Committee, Delaware Estuary Program.
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the United States, 1995. USGS Circular 1200. U.S. Geological Survey,
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Stutz, B. 1992. The Delaware: Portrait of a river. Nature Conservancy, May/
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723-729.
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Chapter 8
Potomac Estuary
Case Study
The Mid-Atlantic Basin (Hydrologic Region 2),
covering a drainage area of 111,417 square potomac
miles, includes some of the major rivers in the Estuary^
continental United States. Figure 8-1 highlights the
location of the basin and the Potomac estuary, the
case study watershed profiled in this chapter.
With a length of 340 miles and a drainage area of
14,670 square miles, the Potomac River ranks 48th
among the 135 U.S. rivers that are more than 100 miles
in length (Iseri and Langbein, 1974). Urban-industrial
areas in the watershed caused severe water pollution
problems during the 1950s and 1960s (see Table 4-2). This
chapter presents long-term trends in population, municipal wastewater
infrastructure and effluent loading of pollutants, ambient water quality,
environmental resources, and uses of the Potomac estuary. Data
sources include USEPA's national water quality database (STORET),
published technical literature, and unpublished technical reports ("grey"
literature) obtained from local agency sources.
With a combined drainage area of 14,670 square miles, the freshwater
and estuarine Potomac River basin is the second largest watershed in the Middle
Atlantic region. The freshwater Upper Potomac River flows more than 220 miles
from the headwaters of the North Branch in the eastern Appalachian Mountains
to the fall line at Little Falls, Virginia, near Washington, DC. Tidal influences in the
Potomac extend 117 miles from the fall line at Little Falls to the confluence with
Chesapeake Bay at Point Lookout, Virginia (Figure 8-2).
In this 117-mile reach, the Potomac River is classified into three distinct
hydrographic regions—tidal river, transition zone, and estuary. The tidal river,
extending 38 miles from the fall line to Quantico, Virginia, is characterized as
freshwater (salinity < 0.5 ppt) with net seaward flow from surface to bottom.
This section of the Potomac River receives the effluent discharge from the major
municipal wastewater treatment facilities in the Washington, DC, metropolitan
Figure 8-1
Hydrologic Region 2 and
the Potomac estuary
watershed.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 8-2
Location map of Middle
and Lower Potomac River.
(River miles shown are
distances from the
confluence of the Lower
Potomac River with the
Chesapeake Bay.)
78
40°
39°
38C
77°
area. The transition zone, extending 29 miles from Quantico, Virginia, to the Route
301 bridge in Maryland, is characterized by variable salinity (0.5-10 ppt) and
significant mixing of freshwater and saltwater from Chesapeake Bay. In the
mesohaline estuary region, extending 50 miles from the Route 301 bridge to
Chesapeake Bay at Point Lookout, Virginia, salinity varies from 5 to 18 ppt, with
estuarine circulation characterized as partially mixed (Haramis and Carter, 1983).
During much of the past century, the Potomac estuary has been character-
ized by severe water pollution problems—bacterial contamination, oxygen deple-
tion, and nuisance algal blooms—resulting from population growth in the Washing-
ton, DC, area and inadequate levels of waste treatment. Historical DO data
provide an excellent indicator to characterize long-term trends in the ecological
status of the Potomac estuary. The water quality benefits attributed to implemen-
tation of secondary and advanced waste treatment by Washington, DC, area
wastewater dischargers to the Potomac estuary represent a major national
environmental success story.
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Chapter 8: The Potomac Estuary Case Study
Physical Setting and Hydrology
The Upper Potomac River, which has a drainage area of 11,560 square
miles, is the major freshwater inflow to the estuary. Based on long-term (1931-
1981) USGS data at Little Falls near the fall line, the mean annual daily flow is
11,406 cfs, with extreme discharge conditions of 374 cfs recorded during the
drought of 1966 and 483,802 cfs recorded during the flood of 1936 (MWCOG,
1989). The long-term (1931-1988) mean 7-day, 10-year low flow (7Q10) at Little
Falls is 628 cfs. Low-flow conditions typically occur from July through September,
with the minimum monthly flow of 4,126 cfs recorded during September (Figure
8-3). The long-term (1951-1980) mean summer (July-September) flow for the
Potomac River at Little Falls was 4,428 cfs (Figure 8-4).
Figure 8-3
Monthly trends of mean,
10th, and 90th percentile
streamflow for the
Potomac River at Little
Falls, VA (USGS Gage
01646500), 1951-1980.
Source: USGS, 1999.
ONDJ FMAMJ JAS
Figure 8-4
Long-term trends in mean,
10th, and 90th percentile
streamflow in summer
(July-September) for the
Potomac River at Little
Falls, VA (USGS Gage
01646500).
Source: USGS, 1999.
T946 1956
90%ile
mean & ratio
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 8-1. Metropolitan Statistical Area (MSA) counties in the Potomac Estuary
case study. Source: OMB, 1999.
Calvert County, MD
Charles County, MD
Frederick County, MD
Montgomery County, MD
Prince George's County, MD
Arlington County, VA
Clarke County, VA
Culpepper County, VA
Fairfax County, VA
Fauquier County, VA
King George County, VA
Loudoun County, VA
Prince William County, VA
Spotsylvania County, VA
Stafford County, VA
Warren County, VA
Alexandria City, VA
Fairfax City, VA
Falls Church City, VA
Fredericksburg City, VA
Manassas City, VA
Manassas Park City, VA
Berkeley County, WV
Jefferson County, WV
Population, Water, and Land Use Trends
In 1996 more than 4.5 million people lived in the Washington, DC, metropoli-
tan area in the vicinity of the tidal river. The Potomac estuary case study area
includes a number of counties identified by the Office of Management and
Budget as Metropolitan Statistical Areas (MSAs) or Primary Metropolitan
Statistical Areas (PMSAs). Table 8-1 lists the MSA and counties included in this
case study. Figure 8-5 presents long-term population trends (1940-1996) for the
counties listed in Table 8-1. From 1940 to 1996, the population in the Potomac
Estuary study area nearly quadrupled (Forstall, 1995; USDOC, 1998).
Figure 8-5
Long-term trends in
population of Washington,
DC, metropolitan area.
Source: Forstall, 1995;
USDOC, 1998.
1940 1950 1960 1970 1980 1990 1996
8-4
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Chapter 8: The Potomac Estuary Case Study
Within the Potomac basin, land use is characterized as forested (55 percent),
agricultural (40 percent), and urban (5 percent) (Jaworski, 1990). A rapid transi-
tion from agricultural land use to suburban land use has occurred since the 1960s
in the Washington, DC, metropolitan area. In contrast to other major metropolitan
areas, industrial activities are a negligible component of the regional economy
(and wastewater loading). Upstream of the fall line, the free-flowing Potomac is
used for five municipal water supply diversions with a total mean withdrawal (ca.
1986) of 386 mgd (MWCOG, 1989). As a result of major improvements in water
quality over the past decade, boating and recreational and commercial fishing
have become important resource uses of the Potomac estuary.
Historical Water Quality Issues
As in many other urban areas centered around rivers and harbors, water
pollution problems have been documented in the tidal river since the turn of the
century (e.g., Newell, 1897). In the late 1950s USPHS officials described the
Potomac near Washington, DC, as "malodorous . . . with gas bubbles from
sewage sludge over wide expanses of the river . . . and coliform content
estimated as equivalent to dilution of 1 part raw sewage to as little as 10
parts clean water." Dissolved oxygen levels near Washington, DC, were
typically less than 1 mg/L during summer low-flow conditions, and nuisance algal
blooms and fish kills were commonplace during the 1940s, 1950s, and 1960s.
Between 1955 and 1960 the stock abundance of American shad in the Potomac
River dropped precipitously despite favorable hydrographic conditions for spawn-
ing and development. American shad in northeastern estuaries such as the
Potomac River, although influenced by spawning success, may be influenced to a
larger extent by mortality suffered by young fish as they pass seaward through
regions of poor water quality (Summers and Rose, 1987).
Legislative and Regulatory History
Following generally accepted engineering practices a century ago, a sewage
collection system was constructed in Washington, DC, in 1870, with wastewater
collected and discharged without treatment into the Potomac River. By 1913
USPHS surveys documented severely polluted conditions resulting from the
discharge of raw sewage. Following the recommendations of city officials in 1920
and a study conducted in the early 1930s, the Blue Plains facility began operation
in 1938 as a primary plant to serve 650,000 people. An unforeseen population
influx related to World War II quickly exceeded the capacity of the new treatment
plant.
In response to the continuing degradation of water quality in the Potomac,
the 1956 Federal Water Pollution Control Act, and subsequent amendments,
served as the mechanism for establishing cooperative federal, state, and local
remedial action plans for wastewater treatment. For more than two decades,
federal, state, and local officials have cooperated in developing regional water
quality management plans and implementing recommended effluent limits.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
In the Washington, DC, region, 13 wastewater treatment plants currently
discharge effluent into the Potomac estuary. As of 1990 nine major plants
(Table 8-2) served about 4 million people and discharged a total of about 615
mgd (ICPRB, 1990). The 370-mgd discharge of the Blue Plains plant, which
serves the population of Washington, DC, accounts for about 75 percent of the
total effluent discharge to the Potomac estuary during low-flow conditions
(Figure 8-6).
Table 8-2. Effluent flow in 1 990 from major tidal
Potomac River municipal wastewater treatment plants
(mgd). Source: ICPRB, 1990.
Alexandria
Arlington
Blue Plains
Dale City
Little Hunting Creek
Lower Potomac
Mattawoman
H.L. Mooney
Piscataway
Total
54
40
370
4
6.6
72
15
24
30
616.6
500
Figure 8-6
Long-term trends in
effluent flow rate of
municipal wastewater
facilities.
Source: MWCOG, 1989.
1940
1950
1960
1970
1980
1990
8-6
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Chapter 8: The Potomac Estuary Case Study
200
150
--100
S1
p
IT)
Q
§
Figure 8-7
Long-term trends of BOD5,
total nitrogen, and total
phosphorus effluent loads
from municipal
wastewater.
Source: Jaworski, 1990;
Nemura, 1992.
1940
1950
1960
1970
1980
Over the past 50 years, trends in BOD5 and nutrient loading have reflected a
growing population and increasing levels of wastewater treatment. The reduction
in BOD5 loading resulted from the implementation of secondary treatment at Blue
Plains in 1959 and at the other facilities from 1960 to 1980. Beginning in the early
1970s, the dramatic drop in phosphorus loading by 1986 resulted from phosphorus
controls implemented at all the major wastewater treatment facilities to minimize
eutrophication in the Potomac estuary. Nitrogen loading, however, has increased
with population in the absence of controls on effluent nitrogen levels (Figure 8-7).
DO, influenced by temperature, wastewater loading, and freshwater flow, is
characterized by seasonal and spatial variations, with minimum levels observed
during the high-temperature, low-flow conditions of summer. Historical DO data
are available to characterize long-term changes in the spatial distribution of
oxygen during the summer (July-September) over a distance of approximately 55
miles from Chain Bridge to Mathias Point. These historical data sets clearly show
the significant problem with oxygen depletion during the 1960s (1960-1964,1966)
with recorded concentrations of less than 2 mg/L downstream of the Blue Plains
wastewater treatment plant (located at about River Mile 106) (Figure 8-8).
20
15-
10-
5-
Summer Mean (July-September)
Chain Bridge-Mathias Ffoint
-120 -110 -100 -90 -80
River Mile from Point Lookout
-70
-60
Figure 8-8
Long-term trends in
summer DO levels at
Chain Bridge-Mathias
Point.
Sources: Davis, 1968;
Thomann and Fitzpatrick,
1982; Fitzpatrick et ai,
1991.
8-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 8-9
Long-term trends in
summer DO levels on the
Potomac River near the
Wilson Bridge (mile 95).
(Data for 1940-1986 from
MWCOG averaged from
June-September, data for
1987-1995 from STORE!
averaged from July-
September.)
Source: MWCOG, 1989;
USEPA (STORET).
1950
1960
1970
1980
1990
2000
Mean summer (June-September) oxygen records obtained from stations
directly influenced by the wastewater discharge from Blue Plains near the
Woodrow Wilson Bridge (RM 95) clearly show long-term trends in the ecological
condition of the estuary from 1940 to 1990 (Figure 8-9). The decline from 1945 to
1960 reflects substantial increases in population and related raw and primary
effluent loading from the Washington, DC, region. Low oxygen levels recorded in
the mid-1960s (1 to 2 mg/L) reflect the reduction of freshwater available for
dilution because of drought conditions (see Figure 8-4) rather than any increase of
pollutant load. The water quality standard for DO of 5 mg/L was typically violated
during the 1960s and 1970s. Compliance was attained for the summer average
condition only after all the regional wastewater treatment plants achieved second-
ary treatment by 1980; minimum summer levels, however, continued to periodi-
cally be less than 5 mg/L (MWCOG, 1989).
Evaluation of Water Quality
Benefits Following Treatment
Plant Upgrades
From a policy and planning perspective, the central question related to the
effectiveness of the secondary treatment requirement of the 1972 CWA is simply
Would water quality standards for dissolved oxygen be attained if primary
treatment levels were considered acceptable?
In addition to the qualitative assessment of historical data, water quality
models can provide a quantitative approach to evaluate improvements in water
quality achieved as a result of upgrades in wastewater treatment. The Potomac
Eutrophication Model (PEM) (Thomann and Fitzpatrick, 1982; Fitzpatrick et al.,
1991) has been used in this study to demonstrate the water quality benefits
attained by the technology- and water-quality-based requirements of the 1972
CWA for municipal wastewater facilities.
8-8
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Chapter 8: The Potomac Estuary Case Study
The Potomac Estuary Model (PEM) was calibrated using observed data
sets collected from 1983 through 1985. In the summer of 1983, an anomalous
bloom of the blue-green alga Microcystis aeruginosa formed a dense, brilliant
green scum-like mat on the surface that extended over a distance of about 20
miles in the central estuary and embayments. Peak chlorophyll levels in the main
river were ~300 ug/L, and dense concentrations as high as -800 ug/L were
recorded in the embayments (Thomann and Mueller, 1987). During the peak of
the bloom in September 1983, dissolved oxygen levels computed with PEM were
in reasonable agreement with the observed monthly mean data (Figure 8-10);
concentrations of ~6 mg/L were observed and simulated in the vicinity of the Blue
Plains wastewater treatment plant (RM 105) (Fitzpatrick et al., 1991). The rapid
increase from ~6 mg/L to observed (~10-16 mg/L) and computed (~12 mg/L)
levels of dissolved oxygen ~5-10 miles downstream from Blue Plains is caused by
high rates of phytoplankton primary productivity associated with peak algal
biomass levels of ~150-250 ug/L (as chlorophyll a) in the vicinity of the Woodrow
Wilson Bridge (RM 95). Further downstream in the transition zone of the
Potomac estuary, observed and computed dissolved oxygen levels decline to -5-7
mg/L in the vicinity of Indian Head (RM 85) to Maryland Point (RM 65) as a
result of the attenuation of the Microcystis bloom by nitrogen limitation and the
effects of salinity toxicity (Fitzpatrick et al., 1991). As documented by Fitzpatrick
et al. (1991), dissolved oxygen, algal biomass, nutrients, BOD5, inorganic carbon,
pH, and salinity, the Potomac Estuary Model is considered well calibrated to the
observed data for the period from 1983 through 1985.
Using data to describe effluent flow, pollutant loading, and hydrologic
conditions during the lower-than-average flow conditions of September 1983, the
calibrated model was used to evaluate the water quality impact of two regulatory
control scenarios based on an assumption of (a) primary treatment and (b)
secondary treatment compared to the existing (ca. 1983) effluent loading for all
the municipal facilities in the Washington, DC, region (Fitzpatrick, 1991) (Figure
8-10). Water quality conditions for these scenarios were simulated using freshwa-
ter flow data for 1983, a year characterized by summer flow (2,333 cfs) that was
about 53 percent of the long-term summer mean flow of the Potomac River (see
-110
-100 -90 -80
River Miles from Point Lookout
-70
-60
Figure 8-10
Potomac Estuary Model
comparison of simulated
DO for primary, secondary,
and greater than
secondary effluent loading
scenarios (observed data
is for September, 1983
calibration).
Source: Fitzpatrick, 1991;
Fitzpatrick et al., 1991.
8-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 8-4). Other than the effluent characteristics, the ratio of ultimate-to-5-day
BOD and the oxidation rate for CBOD (Kd) were the only parameters changed in
the simulations to reflect differences in the proportion of refractory and labile
organic carbon for the different levels of wastewater treatment (Fitzpatrick, 1991;
Lung, 1996,1998; Thomann and Mueller, 1987).
For the primary simulation, a value of Kd = 0.21 day1, obtained from the
original PEM (Thomann and Fitzpatrick, 1982), is typical of wastewater effluent
characterized by the high CBOD concentrations typical of primary treatment
conditions observed during the 1960s. For the secondary simulation, a value of Kd
= 0.16 day1, obtained from the original PEM (Thomann and Fitzpatrick, 1982), is
typical of wastewater effluent characterized by the intermediate CBOD concen-
trations typical of secondary treatment conditions observed during the late 1970s.
For the advanced (actual 1983) loading scenario, a value of Kd = 0.10 day1,
obtained from calibration of the updated PEM (Fitzpatrick et al., 1991), is typical
of wastewater effluent characterized by the low CBOD concentrations of
advanced secondary and tertiary treatment conditions observed during the mid-
1980s.
Under the primary effluent assumption, water quality is noticeably deterio-
rated in comparison to the 1983 calibration results. As a result of the effluent
loading from the Blue Plains treatment plant, DO concentrations in the vicinity of
Washington, DC (RJVI 10-15) are computed to be ~1 mg/L under the primary
effluent scenario. With minimum levels less than 1 mg/L in the vicinity of the Blue
Plains discharge (RM 106), the simulated results for the primary effluent scenario
are remarkably similar to the historical data recorded for 1960-1964 and 1966
during the drought conditions of the 1960s (see Figure 8-8).
Under the secondary effluent assumption, the significant reduction in CBOD
loading significantly improves dissolved oxygen near Washington, DC. In compari-
son to the primary scenario, minimum monthly-averaged oxygen levels increased
to almost 3.5 mg/L from approximately 0.2 mg/L under the secondary effluent
scenario. When compared to the model results for the existing 1983 conditions,
the results of the secondary effluent simulation shows somewhat poorer water
quality conditions for dissolved oxygen. The reason for the failure to achieve
compliance with the 5 mg/L water quality standard for dissolved oxygen over only
a few miles (RM 104-106) is that under the existing loading scenario for 1983, the
370-mgd Blue Plains facility (the largest wastewater discharger to the Potomac
River) has instituted advanced secondary treatment with greater removal of
BOD, ammonia, and phosphorus than is represented in the secondary effluent
scenario (Fitzpatrick, 1991).
As shown with both observed data and state-of-the-art model simulations,
the implementation of secondary and better treatment has resulted in significant
improvements in the DO status of the estuary. As demonstrated with the model
(and actually attained) better than secondary treatment is required to achieve
compliance with the water quality standard of 5 mg/L for DO at the critical
location downstream of Blue Plains (see Figure 8-10). In contrast to the 1950s
and 1960s, the occurrence of low oxygen conditions has been virtually eliminated
in the Upper Potomac estuary (see Figure 8-8). Additional improvements in
Potomac water quality, in terms of reduced algal biomass and increased water
clarity still greater improvements in dissolved oxygen levels, have been achieved
as a result of advanced secondary and tertiary levels of wastewater treatment for
the Upper Potomac estuary.
8-10
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Chapter 8: The Potomac Estuary Case Study
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
In addition to public water supply withdrawals (from the free-flowing river)
and wastewater disposal from a number of municipalities, the uses of the Upper
Potomac estuary include recreational and commercial fishing, boating and naviga-
tion, bird-watching, and secondary contact water-based recreation (e.g., wind-
surfing). Although recreational opportunities were severely limited during the
1940s, 1950s, and 1960s because of water pollution, the improvements in water
quality during the 1980s have resulted in a significant increase in a variety of
recreational uses of the river by the urban population of Washington, DC. Boat-
ing; windsurfing; walking, running, and bicycling on trails along the riverbanks; and
recreational fishing are now extremely popular activities in the tidal river in the
vicinity of Washington, DC.
Designated Uses and Bacterial Trends
Unlike the uses of many other major urban waterways, swimming, because
of limited access from the shoreline and a lack of public bathing beaches, is not
considered a major use of the Upper Potomac estuary. Most of the Potomac
River from the upper freshwater reaches near Point of Rocks, Maryland, to the
estuarine waters near Point Lookout, Maryland, is designated for primary contact
recreational uses (swimming). In the vicinity of Washington, DC, however, the
waters of the tidal Potomac are designated for secondary contact recreational
uses such as boating or windsurfing. The estuarine portions of the Potomac
downstream of Smith Point, Maryland, have been designated for shellfish harvest
and must comply with more stringent bacteria level standards than those set for
primary or secondary contact recreational uses. To protect public health from
risks resulting from direct contact with the waters of the Potomac or ingestion of
shellfish from the estuary, water quality standards have been established by the
state of Maryland, the District of Columbia, and the state of Virginia for the
maximum log mean fecal coliform bacteria levels (as most probable number
(MPN) per lOOmL) as follows:
• Primary contact < 200 MPN/100 mL
• Secondary contact < 1000 MPN/100 mL
• Shellfish harvest < 14 MPN/100 mL
Based on long-term historical water quality data from measurements taken
downstream of the Blue Plains discharge, it is apparent that the introduction of
effluent chlorination in 1968 resulted in dramatic improvements in bacterial con-
tamination of the tidal Potomac (Figure 8-11). Prior to chlorination of wastewater
effluent, summer coliform levels, typically on the order of 105 to 106 MPN/100 mL
from 1940 to the mid-1960s, consistently were in violation of the secondary contact
standard of 1,000 MPN/100 mL. Even with the dramatic reductions, summer
bacteria levels still exceeded water quality standards during the 1970s. As bacteria
loadings from the Washington area municipal wastewater plants continued to
8-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 8-11
Long-term trends in total
coliform densities in the
Potomac River down-
stream of the Blue Plains
POTW near Gunston Cove,
VA
Source: USEPA (STOHET).
10000000=
O- 1000000:
E
8
5 looooo:
I
I
CD
1940
1950
1960
1970
1980
1990
decrease during the 1980s, summer bacteria densities began to be in compliance
with the water quality standard for both primary and secondary contact. Since the
1980s periodic violations of bacteria level standards in the tidal Potomac have
usually been related to storm event discharges from combined sewer overflows in
the District of Columbia and Alexandria, Virginia (MWCOG, 1989).
Since the passage of the 1965 Water Quality Act, well-planned and coordi-
nated water pollution control programs in the Washington metropolitan region
have succeeded in achieving substantial reductions in pollutant discharges to the
Potomac estuary. Despite the remarkable improvements in the bacteria levels of
the tidal Potomac, it is unlikely that President Johnson's 1965 pledge to "reopen
the Potomac for swimming" will be fulfilled because of the lack of beaches
along the shoreline and access for swimming.
Submersed Aquatic Vegetation, Fishery,
and Waterfowl Resources
In numerous accounts of the early colonists, the natural abundance of
waterfowl and fishery resources of the Potomac basin was considered an impor-
tant factor in attracting new colonists to the region. Like many freshwater and
marine environments, the shallow littoral areas of the tidal Potomac River near
Washington, DC, were characterized by extensive beds of a variety of species of
aquatic macrophytes, or submersed aquatic vegetation (SAV), during the late
1800s and early 1900s (Carter et al., 1985). Detailed maps in 1904 and 1916, for
example, showed extensive "grass" beds in Gunston Cove and shallow areas of
the Maryland and Virginia sides of the river. In addition to the direct effect on the
survival and condition offish populations due to low DO concentrations caused by
high organic loadings, fish populations are indirectly influenced by SAV abun-
dance, necessary to provide nursery habitat for juvenile fish (Fewlass, 1991).
8-12
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Chapter 8: The Potomac Estuary Case Study
Increased municipal wastewater loading from the Washington area and the
resulting poor water quality was most likely responsible for the disappearance of
SAV from the tidal Potomac River (Carter et al., 1985; Carter and Paschal,
1981), first noticed in 1939. During the 1940s and 1950s, widespread losses of
SAV were common, not only in the Potomac, but also throughout the Chesapeake
Bay basin (Carter et al., 1985). Although the SAV beds were severely diminished
by the late 1930s, periodic nuisance "invasions" of submersed aquatic vegetation
were recorded in the tidal Potomac during the 1930s (water chestnut) and from
1958 through 1965 (Eurasian watermilfoil) (Jaworski, 1990).
Trends in Suspended Solids Load and
Water Clarity
By the late 1970s, SAV in the Washington, DC, area had effectively disap-
peared from the tidal Potomac (Carter et al., 1985). The loss of SAV in the
Potomac, and elsewhere in Chesapeake Bay region, has been attributed to the
decreased availability of light in the littoral zone resulting from increased turbidity
from the discharge of suspended solids and nutrients to the estuary (Carter et al.,
1985). High levels of algae reduced light penetration and inhibited the growth of
SAV. The natural abundance of fish and waterfowl of the Potomac, documented
by the early colonists, was in fact directly related to the abundance and distribu-
tion of SAV in the shallow areas of the river. Redhead ducks, canvasbacks, and
migrating widgeons and gadwalls feed on SAV, and other ducks such as mergan-
sers feed on juvenile fish that depend on SAV for spawning and development
(Forsell, 1992). The absence of SAV during the 1940s through 1970s resulted in a
loss of habitat and food resources for fish and waterfowl dependent on the
presence of the SAV beds.
The long-term ecological effects of the dramatic reductions of municipal
wastewater loading of phosphorus (Figure 8-7) and suspended solids (Figure 8-
12) to the estuary that began during the 1970s became apparent in the early
150-
100-
50-
1970
1975
J
III!
• •••I
1980
1985
1990
Figure 8-12
Long-term trends in
municipal wastewater
loading of suspended
solids in the tidal Potomac
River.
Source: Nemura, 1992.
8-13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
1980s with the surprising reappearance of SAV beds in the tidal Potomac
(Carter and Rybicki, 1990). The return of the SAV beds was directly related to
improvements in the clarity of the water (Figure 8-13), resulting from reductions
in suspended solids and phosphorus loading from municipal wastewater dis-
charges to the estuary and subsequent reductions in ambient phosphorus and
algal biomass (Figure 8-14) (Carter and Rybicki, 1990; Jaworski, 1990; Carter
and Rybicki, 1994). The presence of the SAV beds, in turn, has further enhanced
water quality by physical settling of particulate solids, filtering of nutrients by
plant uptake, and reduction of algal production in the water column (Figure 8-15).
The reemergence of SAV beds in the tidal Potomac has resulted in dramatic
increases in the diversity, abundance, and distribution of waterfowl (Figures 8-16
and 8-17).
Figure 8-13
Long-term trends in SAV
and water transparency in
the tidal Potomac River.
Sources: Carter and
Rybicki, 1990; Nemura,
1992; USEPA (STORET).
i
c 3000-
o
^
1 2000-
D
0-
A
* *-^ 4
* ^* " *^ * ^^ A
v \ r\
X it v--^
V
nil
1970 1975 1980
r-l
,
1
r-i
...
.
985
p
• -
k ,'
Ai
^
-
1
990
-u.u
-0.6
-0.8
'
CO
I SAV
c • water transparency
Figure 8-14
Long-term trends in algal
biomass and total
phosphorus in the tidal
Potomac River.
Source: USEPA, 1992.
0.5
1965-69 1970-74 1975-79 1980-84 1985-89 1990-91
^| Algae
-*- Total-P
0.0
8-14
-------
Chapter 8: The Potomac Estuary Case Study
Submersed Aquatic Vegetation
20
40 60
Density of SAV: Increase
80
100
Figure 8-15
Conceptual relationship of
SAV abundance and water
clarity.
Source: Carter and
Rybicki, 1990, 1994;
Kemp et ai, 1984.
10000-
Chain Bridge to Wicomico River
1956-60 1961-65 1966-70 1971-75 1976-80 1981-85 1986-90 1991-92
I Canada Geese
Canvasback Ducks
Figure 8-16
Long-term trends of
waterfowl in the upper
Potomac River.
Observation from
Washington, DC, to Route
301 bridge.
Source: Forsell,
Unpublished data.
50%
40%-|
3
£ 30%-
Upper Chesapeake Bay: 1958-75
Percentage of North American Flyway Population
100 200 300 400
Relative Abundance of SAV »
500
Figure 8-17
SAV and waterfowl
abundance in Upper
Chesapeake Bay (1958-
1975).
Source: Kemp et al., 1984.
8-15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 8-18
SAV abundance and
fishery resources in the
Choptank River.
Source: Kemp et al., 1984.
No SAV Dense SAV
Density of SAV: Increase 0
Fish surveys documented significant increases in species diversity and
abundance from 1984 to 1986 (MWCOG, 1989) that are consistent with the SAV
and fisheries abundance data reported for the Choptank River on the eastern
shore of Maryland (Kemp et al., 1984) (Figure 8-18).
Before the disappearance of the SAV beds, waterfowl populations (ca.
1929-1930) were about an order of magnitude greater than after the disappear-
ance of SAV during the 1950s, when the annual average waterfowl census was
6,547 birds. Historical data from the Upper Chesapeake Bay (1958-1975) are
useful to illustrate the relationship between the availability of SAV, fisheries, and
waterfowl populations (Figures 8-17 and 8-18). The importance of SAV in the
overall biological health of the tidal Potomac is clearly demonstrated with recent
observations of a doubling of waterfowl abundance and an increase in the
diversity of species (MWCOG, 1989). In 1972 only 9 species of ducks wintered
in the Potomac tidal river and transition zone (represented by more than one
individual observed in winter transect counts); by 1992 the number of species
had increased to 17 (Forsell, 1992). Fall-migrating, SAV-eating widgeons and
gadwalls, absent from the estuary in winter for 15 years, have lengthened their
stay in the Potomac, possibly encouraged by recent warmer winters and more
plentiful food supplies. Populations offish-eating mergansers, increasing since
the 1970s, may be responding to increasing fish habitat available since the
reemergence of SAV beds. Populations of Canada geese, tundra swans, and
mallards, although not directly linked to SAV, are also increasing in the tidal
Potomac, this trend has also been observed in other areas of the northeast.
Fishery surveys in the tidal Potomac, and elsewhere in the Chesapeake Bay,
clearly document an increase in abundance and diversity offish species. Juvenile
fish survey data, collected between 1965 and 1987 at Indianhead and Fenwick in
the tidal river, were analyzed using the Index of Biotic Integrity (IBI) (Figure 8-
19). The IBI, developed by Karr (1981) for use in midwestern streams, has been
adapted for use in other areas. This index is a composite of 12 ecological at-
tributes offish communities, including species richness, indicator taxa (both
intolerant and tolerant), trophic guilds, fish abundance, and incidence of hybridiza-
8-16
-------
Chapter 8: The Potomac Estuary Case Study
Figure 8-19
Long-term trends in fishery
resources of the Potomac
estuary based on Index of
Biotic Integrity (IBI).
Source: Jordan,
Unpublished data.
tion, disease, and abnormalities (Karr et al., 1986). IBI scores range from a low
of 12 to a high of 60. A score of 12 is assigned to conditions where no fish are
present even after repeated sampling; a score of 60 is assigned to conditions
comparable to the best habitats without human disturbance (Karr et al., 1986).
The trend in the IBI at Indianhead (Jordan, 1992, unpublished data) shows that
the river quality for fish increased from poor, indicating an impaired or restricted
habitat (IBI scores in the 20 to 30 range), to fair, indicating slightly impaired
habitat (IBI scores in the 40 to 50 range). These data indicate that in the late
1960s and early 1970s the fish community at Indianhead was dominated by a few
tolerant species, with few fish present at all in some years. In the last 20 years, a
general upward trend in river quality for fish has been observed, evidenced by
increasing numbers of pollution-intolerant species and a species mix suitable to
provide for a reasonably balanced trophic structure. Indicator variables currently
measured at Indianhead are at about two-thirds of their expected level in undis-
turbed habitats. The rise in the IBI at Indianhead, where a wastewater treatment
plant discharge is located, is in contrast to stable or declining trends observed at
other locations that lack wastewater treatment plant outfalls (Jordan, 1992,
unpublished data).
In addition to the direct effect on the survival and condition offish popula-
tions due to low DO concentrations due to high organic loadings (Tsai, 1991), fish
populations are indirectly influenced by SAV abundance, necessary to provide
nursery habitat for juvenile fish (Fewlass, 1991). The quality of river habitat for
fish has increased with the resurgence of SAV habitat in comparison to areas
characterized by the absence of SAV beds. During 1984-1986, years character-
ized by a rapid increase in the distribution of SAV beds (primarily Hydrillo) (see
Figure 8-13), fishery surveys near Washington, DC, clearly showed an increase in
species diversity; abundance increased from 79 to 196 fish per net haul over the
same 2-year period (MWCOG, 1989). The relationship of SAV and fishery data
from the tidal Potomac is consistent with data reported by Kemp et al. (1984) for
the Choptank River on the eastern shore of Maryland (see Figure 8-18).
8-17
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
"...in the 1950s and 1960s
the Potomac was a flowing
cesspool...It was a dis-
grace, it was so polluted. If
you fell in the river, it was
recommended you go ti
the hospital for examina-
tion. Now the river is much
better. Pollution controls
are higher and the fish
population's are mostly
solid. But the people still
think of it as the old river.
So people don't under-
stand how good the fishing
is here."
Travel Section,
Washington Post,
August 30, 1998
(Tidwell, 1998).
SAV and Ecological Resources
The evidence is clear from observations in Chesapeake Bay and the tidal
Potomac River that the presence of SAV beds is critical for a healthy and diverse
aquatic ecosystem. The presence of SAV beds has the following positive impacts:
• Increases habitat and food resource availability
• Increases species diversity and abundance
• Increases fishery resources
• Increases waterfowl populations
• Increases recreational opportunities (fishing, hunting, bird-watching)
• Enhances water quality
• Removes nutrients
• Allows particulate material to settle out
• Reoxygenates water column by photosynthesis
Summary and Conclusions
Water quality and biological resources data clearly illustrate the cause-effect
relationship of reductions in wastewater loading of BODs, nutrients, and sus-
pended solids and improvements in the ecological resources of the tidal Potomac.
As a result of the significant improvements in water quality, the Potomac estuary
emerged during the 1990s as one of the top-ranked largemouth bass sport fisher-
ies supporting increasingly popular recreational fishing activities, including profes-
sional fishing guide services and several Bassmasters fishing tournaments. One of
the earliest professional guides, Ken Penrod of Outdoor Life Unlimited in
Beltsville, Maryland, now has one of the largest freshwater fishing guide services
in the nation. Guides like Penrod have reported that since 1982 every year has
been better than the previous year in terms of the quantity and quality offish that
have returned to the waters of the tidal Potomac (Soltis, 1992). The quality of
river habitat for fish has increased with the resurgence of SAV habitat in com-
parison to areas characterized by the absence of SAV beds. The Potomac River
was selected as an American Heritage River in 1998, acknowledging the substan-
tial improvements in water quality and ecological conditions. In addition, some
300 people took part in the 1999 Bassmasters Fishing Tournament on the
Potomac (Fishing Tournament Marks a River's Rebound, 1999).
References
Carter, V., and J.E. Paschal. 1981. Biological factors affecting the distribution
and abundance of submerged aquatic vegetation in the tidal Potomac River,
Maryland and Virginia. Estuaries 4(3): 300.
Carter, V, J.E. Paschal, and N. Bartow. 1985. Distribution and abundance of
submersed aquatic vegetation in the tidal Potomac River and estuary,
Maryland and Virginia, May 1978 to November 1981. Water-Supply
Paper 2234-A. U.S. Geological Survey, Reston, VA.
Carter, V, and N.B. Rybicki. 1990. Light attenuation and submersed macrophyte
distribution in the tidal Potomac River and estuary. Estuaries 13(4): 441-452.
8-18
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Chapter 8: The Potomac Estuary Case Study
Carter, V. and N.B. Rybicki. 1994. Role of weather and water quality in
population dynamics of submersed macrophytes in the tidal Potomac River.
Estuaries 17(2): 417-426.
Davis, R.K. 1968. The range of choice in water management: A study of
dissolved oxygen in the Potomac Estuary. Published for Resources for the
Future, Inc. by The Johns Hopkins Press, Baltimore, MD.
Fewlass, L. 1991. Statewide fisheries survey and management study V:
Investigations of largemouth bass populations inhabiting Maryland's
tidal waters. Maryland Department of Natural Resources, Tidewater
Administration, Annapolis, MD.
Fitzpatrick, J.P. 1991. HydroQual, Inc., Mahwah, NJ. Personal communication,
September 18, 1991.
Fitzpatrick, J.P., et al. 1991. Calibration and verification of an updated
mathematical model of the eutrophication of the Potomac estuary.
Prepared for Metropolitan Washington Council of Governments, Washington,
DC, by HydroQual, Inc.
Forsell, D. Unpublished data. U.S. Fish and Wildlife Service.
Forsell, Doug. 1992. U.S. Fish and Wildlife Service. Personal communication,
October 22, 1992.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to 1990.
U.S. Bureau of the Census, Population Division, Washington, DC. .
Haramis, G.M., and V. Carter. 1983. Distribution of submersed aquatic macro-
phytes in the tidal Potomac River. Aquatic Botany 15(1983): 65-79.
ICPRB. 1990. The healing of a river, The Potomac: 1940-1990. Interstate
Commission on the Potomac River Basin, Rockville, MD.
Iseri, K.T., and W.B.Langbein. 1974. Large rivers of the United States. Circular
No. 686, U.S. Department of the Interior, U.S. Geological Survey.
Jaworski, N.A. 1990. Retrospective study of the water quality issues of the
Upper Potomac estuary. Reviews in Aquatic Science 3(2): 11-40.
Jordan, S. Unpublished data. Potomac River Fisheries Commission.
Karr, J.R. 1981. Assessment of biotic integrity using fish communities. Fisheries
6(6): 21-27'.
Karr, J.R., K.D. Fausch, PL. Angermeier, PR. Yant, and I.J. Schlosser. 1986.
Assessing biological integrity in running waters: A method and its
rationale. Special Publication 5. Illinois Natural History Survey, Champaign,
IL.
Kemp, W.M, W.R. Boynton, R.R. Twilley, J.C. Stevenson, and L.G. Ward. 1984.
Influences of submersed vascular plants on ecological processes in Upper
Chesapeake Bay. In The estuary as a filter, ed. VS. Kennedy, pp. 367-394.
Academic Press, New York.
Lung, W. 1996. Postaudit of Upper Mississippi River BOD/DO Model. Jour.
Environmental Engineering, 122(5):350-358.
Lung, W. 1998. Trends in BOD/DO Modeling for Waste Load Allocation. Jour.
Environmental Engineering, 124(10):1004-1007.
MWCOG. 1989. Potomac River water quality, 1982 to 1986: Trends and
issues in the metropolitan Washington area. Metropolitan Washington
Council of Governments, Department of Environmental Programs, Washing-
ton, DC.
8-19
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Nemura, A. 1992. Metropolitan Washington Council of Governments, Depart-
ment of Environmental Programs, Washington, DC. Personal communication,
March 3, 1992.
Newell, F.H. 1897. Pollution of the Potomac River. National Geographic
(December 1997): 346-351.
OMB. 1995. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
Soltis, S. 1992. Rebirth of an American river. Washington Flyer Magazine
(March/April): 22-25.
Summers, K.J., and K.A. Rose. 1987. The role of interactions among environ-
mental conditions in controlling historical fisheries variability. Estuaries 10(3):
255-266.
Thomann, R.V., and J.P. Fitzpatrick. 1982. Calibration and verification of a
mathematical model of the eutrophication of the Potomac estuary.
Prepared for Department of Environmental Services, Government of the
District of Columbia, Washington, DC, by HydroQual, Inc.
Thomann, R.V., and J.A. Mueller. 1987. Principles of surface water quality
modeling and control. Harper & Row, Inc., New York, NY.
Tidwell, M. 1998. Where is this man fishing? The Washington Post, Travel
Section, Page El, E8-E10, August 30.
Tsai, Chu-Fa. 1991. Rise and fall of the Potomac River striped bass stock: a
hypotheiss of the role of sewage. Trans. Amer. Fish. Soc. 120(1): 1-22.
USDOC. 1998. Census of population and housing. U.S. Department of
Commerce, Economics and Statistics Administration, Bureau of the Census -
Population Division, Washington, DC.
USEPA. 1992. Water quality goals for living resources: Role in the Chesa-
peake Bay nutrient reevaluation, summary and preliminary results.
USEPA Chesapeake Bay Program, Annapolis, Maryland.
USEPA (STORET). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
watersheds, Washington, DC.
USGS. 1999. Streamflow data downloaded from the U.S. Geological Survey's
National Water Information System (NWIS)-W. Data retrieval for historical
Streamflow daily values, .
8-20
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Chapter 9
The James
Estuary Case
Study
Figure 9-1 highlights the location of the James
estuary case study watershed (catalog units) identified as
one of the urban-industrial waterways affected by
severe water pollution problems during the 1950s and
1960s (see Table 4-2). The James River basin, at the
southern boundary of the Mid-Atlantic Basin, is one of
the most important water resources in the Common-
wealth of Virginia (Figure 9-2).
As the largest river in the state, the James River
extends more than 400 miles from its mouth at the
Chesapeake Bay to its headwaters near the West
Virginia state line. The river is a recognized asset to
the surrounding residential and metropolitan areas,
providing recreational opportunities such as boating and
fishing.
The James River is known for its annual national
Bassmasters fishing tournaments, and it has exceptional Class IV
white water rapids in the drop between the riverine and estuarine
portions of the river in Richmond, Virginia. The river is also an asset to
commerce and industry, serving as an important water supply and, as such, a
catalyst for economic growth.
Physical Setting and Hydrology
The James River is a typical coastal plain estuary draining to the Chesa-
peake Bay. The variation of depth, cross-sectional area, and tidal velocity in the
James River from Richmond to the Chesapeake Bay is significant. For example,
the cross-sectional average depths vary from about 10 feet in areas with shallow
side embayments to 25 to 30 feet in the deepwater channel. The river generally
widens in the downstream direction, although natural constrictions occur at
Figure 9-1
Hydrologic Region 2 and
the James estuary
watershed.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 9-2
Location map of the James River basin. River miles shown are distances from Chesapeake Bay at the mouth of the
James River.
79°
78°
77°
38C
37°
38°
37°
78°
77°
several locations. Cross-sectional area varies markedly, from the deep, narrow
channel in the upstream section to broad, shallower profiles downstream.
Upstream freshwater flow to the study area is monitored at the USGS
gaging station near Richmond, Virginia, on the James River. The freshwater flow
to the James River is contributed by runoff from 6,758 square miles of woodland
and agricultural areas upstream of the city of Richmond. A relatively small
additional flow enters the study area via the Kanawha Canal, bypassing the
USGS gage near Richmond. The combined average annual flow in the river at the
gage is 6,946 cfs (1937-1998). A relatively small intervening drainage area
provides a nominal increase in in-stream flow between Richmond and the
confluence with the Appomattox River. Water is withdrawn from the James River
for both municipal and industrial purposes and then returned to the river. Treat-
ment is provided by all users except those who use the water solely for cooling
purposes. Long-term interannual and mean monthly trends in streamflow for the
James River near Richmond, Virginia, are shown in Figures 9-3 and 9-4.
9-2
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Chapter 9: James Estuary Case Study
Figure 9-3
Trends of mean, 10th, and
90th percentile statistics
computed for summer
(July-September)
streamflow for the James
River (USGS Gage
02037500 near Richmond,
Virginia).
Source: USGS, 1999.
1990
- - - 90%ile
mean & ratio
Figure 9-4
Monthly trends in
streamflow for the James
River. Monthly mean, 10th,
and 90th percentile
statistics computed for
1951-1980 (USGS Gage
02037500 near Richmond,
Virginia).
Source: USGS, 1999.
ONDJFMAMJJAS
Population Trends
The James estuary case study area includes a number of counties identified
by the Office of Management and Budget as Metropolitan Statistical Areas
(MSAs) or Primary Metropolitan Statistical Areas (PMSAs). Table 9-1 lists the
MSAs and counties included in this case study. Figure 9-5 presents long-term
population trends (1940-1996) for the counties listed in Table 9-1. From 1940 to
1996, the population in the James estuary case study area more than tripled
(Forstall, 1995;USDOC, 1998).
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 9-1. Metropolitan Statistical Area (MSA) counties in the James estuary case
study. Source: OMB, 1999.
Norfolk-Virginia Beach-Newport News,
VA-NC MSA
Currituck County, NC
Gloucester County, VA
Isle of Wight County, VA
James City County, VA
Mathews County, VA
York County, VA
Chesapeake City, VA
Hampton City, VA
Newport News City, VA
Norfolk City, VA
Poquoson City, VA
Portsmouth City, VA
Suffolk City, VA
Virginia Beach City, VA
Williamsburg City, VA
Richmond-Petersburg, VA MSA
Charles City County, VA
Chesterfield County, VA
Dinwiddie County, VA
Goochland County, VA
Hanover County, VA
New Kent County, VA
Powhatan County, VA
Prince George County, VA
Colonial Heights City, VA
Hopewell City, VA
Petersburg City, VA
Richmond City, VA
Figure 9-5
Long-term trends in
population in the James
estuary basin.
Sources: Forstall, 1995;
USDOC, 1998.
OJ
1940 1950 1960 1970 1980 1990 1996
9-4
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Chapter 9: James Estuary Case Study
Historical Water Quality Issues
The estuarine system starts near Richmond, where the fall line is located,
and extends approximately 100 miles from the mouth of the river. The historical
water quality concerns in the estuarine system have been dissolved oxygen and
increased nutrient loads. DO is affected by the carbon and nitrogen components
of the wastewater effluents. It is also influenced indirectly by the phosphorus
content of these sources insofar as the latter stimulates phytoplankton growth.
In 1947 the 14-mile stretch of the James River east of Richmond was
described as "dead." In 1963 conditions had not improved despite growing public
concern. The Richmond News Leader described the river as a sewer. After
powerboat tour of the river, the editor described the river as green with algae,
septic, and laden with dead and dying fish. Even the hardy catfish, which normally
tolerates severely polluted waters, was observed gasping for its last breath. The
only birds in sight were circling turkey vultures, attracted by the floating offal. At
that time, the sewage collection system for Richmond was only partially opera-
tional and only 58 percent of the design flow of the city's sewage treatment plant
was being used. Raw sewage was being discharged into the James through Gillies
Creek, and it seemed doubtful that the river would ever meet the minimum
standard of 4.0 mg/L of dissolved oxygen required to permit recreational river
uses (Richmond News Leader, 1963).
Legislative and Regulatory History
Concern over the severely degraded conditions in the James River prompted
the General Assembly to establish the State Water Control Board (SWCB) in
1946. The Board used its authority to put pressure on the city of Richmond to
expand its treatment facilities and on industries to cease their discharges into the
river (Richmond News Leader, 1963). Although the city responded favorably and
hopes were raised that the river could be fishable again within 10 years, a brief
inspection of the river in 1963 revealed that the expectations of the Game and
Inland Fisheries Commission had been overoptimistic. The river was as dead as it
had been in 1947.
The most significant impetus for change came with the passage of the
federal Clean Water Act in 1972. This legislation forced states and localities to
clean up municipal discharges and provided federal and state money with which
to do it. Richmond upgraded its sewage treatment plant in 1974 to remove as
much as 80 percent of the suspended solids (secondary treatment) (Richmond
Times-Dispatch, 1992). Later upgrades included a 500-million-gallon storm
overflow basin in 1983, a $73 million filtering system in 1990, and an agreement in
1992 to spend $82 million for more improvements scheduled for completion in
1998 (Richmond Times-Dispatch, 1992).
Water supply and wastewater treatment facilities have been developing at a
rate commensurate with growth in the James River basin over the past few
decades. As a result, the James River, including the Appomattox River, has
received increased quantities of treated effluent from both municipal and industrial
sources. The Virginia SWCB realized the necessity of planning for waste treat-
ment requirements many years ago. Between 1960 and 1962, several water
9-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
quality studies were conducted to document the water quality conditions in the
James River. These studies were among the earliest to quantitatively evaluate the
natural assimilation capacity of the James River in the Hopewell and Richmond
areas and to estimate the effect on stream quality of local industrial waste
discharges.
Recognizing that proper planning must be implemented on a regional basis to
protect the river system from impairment of its numerous desirable uses, SWCB
entered into an agreement with the USEPA in 1971, under section 3(c) of the
Federal Water Pollution Control Act of 1965, to study the James River. A princi-
pal outcome of this effort, completed in 1974, was the development of a James
River ecosystem model by the Virginia Institute of Marine Science (VIMS). The
SWCB used this model for wasteload allocations in the James River. Following
the 3(c) study, the Richmond-Crater 208 study was funded and a second detailed
water quality management model, the James Estuary Model (JEM), was devel-
oped for the upper James River estuary. This model was found to be inconsistent
with the VIMS model, and a review of both models was conducted by
HydroScience, Inc. The VIMS model was modified, and the revised James River
model (JMSRV) was recalibrated for use in updating wasteload allocations
(Hydroscience, 1980). The SWCB staff used the latter model to develop
wasteload allocations, i.e., the Upper James River Wasteload Allocation Plan, in
1982 (SWCB, 1982).
Nutrient reduction has also been considered, and control measures have
been implemented as part of the effort to clean up the Chesapeake Bay. The
1987 Virginia General Assembly took action to reduce nutrient enrichment by
enacting a phosphate detergent ban. The next step was taken in March 1988
when the Virginia SWCB adopted the Policy for Nutrient-Enriched Waters and a
water quality standard designating certain waters as nutrient-enriched. Under the
policy, municipal and industrial wastewater treatment plants with flows higher
than 1 mgd are required to remove phosphorus to meet a 2-mg/L limit. Facilities
are given up to 3 years to complete plant modifications to meet this requirement.
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
Pollutant loads from POTWs have been reduced significantly over the past
two decades. In 1971 a large number of the municipal wastewater treatment
plants provided primary treatment. By 1984 there were more than 20 major point
source (municipal and industrial) discharges in the James River estuary from
Richmond to the mouth of the Chesapeake Bay. Table 9-2 lists the major munici-
pal and industrial treatment facilities discharging to the James River during 1983.
Figure 9-6 illustrates the locations of these point sources. Some of the municipal
facilities were consolidated to form regional treatment plants. In the early 1980s
all POTWs achieved secondary treatment levels except the Lambert's Point
plant, which was considered at an advanced primary level (with phosphorus
removal). Since the early 1980s, waste load allocation studies have been prepared
to recommend further reductions of the BOD loads in the upper estuary. Some of
9-6
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Chapter 9: James Estuary Case Study
Table 9-2. Major point source
Source: Lung and Testerman,
loads to the James
1989.
Discharger River Mile'
Richmond
DuPont
Falling Creek
Proctors Creek
Reynolds Metals
VEPCO
American Tobacco
ICI
Philip Morris
Allied-Chester
Allied-Hopewell
Stone Container
Hopewell
Williamsburg
James River
Boat Harbor
Nansemond
Army Base
Lambert's Points
Petersburg2
97.8
92.7
92.2
86.9
86.9
86.7
81.5
80.6
79.8
78.5
77.2
76.8
76.1
88.9
estuary in September
Flow
(mgd)
56.5
6.9
7.2
3.1
0.1
0.08
0.07
0.06
0.0
0.0
-13.5
35.8
9.2
12.5
16.1
6.8
12.1
20.2
1983.
CBOD,
(Ib/day)
4512
202
714
2602
1
0
84.8
8.9
83.2
3859
4809
16200
229
436
410
770
413
21893
1 Distance from the Chesapeake Bay.
2 10.8 miles from the James River
Richmond
Richmond WTP,
DuPont
Falling Ck WT
Proctoat Ck WTP
Am. Tob.
ICI Am.
Phil. Mor./Ald ehtrdd
Appomattox
Chlckahomlny River
Aid. Hopewell ' •-'••:':..
Hopewell WTP
Hopewefl
Figure 9-6
Locations of major point
source discharges to the
James estuary.
Source: Lung and
Testerman, 1989.
•vWilliomsburg WTP
Checopeoke
Boy
9-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 9-3. Effect of phosphate detergent ban: Hampton
Roads Sanitation District. Source: Lung and Testerman,
1989.
Time Period
Pre-Ban
Transition
Post-Ban
Reduction
Influent
(mg/L)
7.4
5.6
4.9
34%
Effluent
(mg/L)
5.3
3.7
2.5
53%
them, such as those in the Hampton Roads Sanitation District, achieved BOD5
concentrations in the effluent much lower than 30 mg/L.
A study by the Virginia SWCB showed that the phosphate detergent ban
has resulted in reductions of total phosphorus concentrations of 34 percent for
POTW influent and 50 percent for effluent (SWCB, 1990). The SWCB's analysis
was based on the data collected from the POTWs operated in the Hampton
Roads Sanitation District, which operates nine POTWs in the James River basin.
The total phosphorus concentrations measured during different periods of the
study are shown in Table 9-3.
It should be pointed out that the analysis shown in Table 9-3 was based on
the POTWs that did not have phosphorus removal. The phosphate detergent ban
would have no effect on the effluent phosphorus concentration from the POTWs
that remove phosphorus. Eventually, when the POTWs remove phosphorus to
meet the 2-mg/L requirement, the ban will reduce the costs of phosphorus
removal by reducing the influent concentrations.
The upstream boundaries and tributaries the watershed of the estuary
account for approximately 94 percent of the drainage area measured below the
confluence of the James and Chickahominy rivers. The area adjacent to the
Appomattox and James rivers below Richmond is thus a small fraction of the total
area drained by this system. Runoff from the contiguous drainage area during the
low-flow summer months represents a small fraction of the total river flow and
has a negligible effect on the water quality in the watershed. The importance of
the upstream pollutant loads was reported by HydroQual Inc. (1986). For ex-
ample, in the James, the upstream ultimate BOD load is larger than any point
source load, and the nitrogenous BOD (NBOD) is nearly equal in magnitude to
several of the largest point source inputs. Similarly, the Appomattox River bound-
ary load is significant relative to the Petersburg wastewater treatment plant
discharge, the only significant point source input to this river. Further, the three
point source inputs, the Richmond and Hopewell treatment plants and Allied-
Hopewell, account for the major portion of the point source loads to the James.
The nonpoint source runoff load was shown to be relatively small in comparison
to the other inputs to the system (HydroQual, Inc., 1986).
It should be pointed out that CSO loads might be significant inputs to the
river system during wet weather conditions and might also be a factor in the
sediment interactions. In view of the purpose of this study, CSOs are not included
9-8
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Chapter 9: James Estuary Case Study
in this analysis. The CSO impacts are indirectly incorporated into the modeling
analysis to the degree that they are a component in the sediment oxygen demand
rates determined by HydroQual (1986).
Figure 9-7 shows historical data of DO concentrations in the James estuary.
The June 1971 survey shows that the river reach from Richmond to Hopewell
was dominated by the waste discharges from and near Richmond. During that
survey, the river was under a moderately high temperature and high flow. Conse-
quently, the DO sag was carried downstream far enough (about 35 miles from
Richmond) to merge with the Hopewell area discharges. Downstream from
Hopewell, the DO concentrations started a slow recovery. In the lower estuary
from Mulberry Island (river mile 27) to Old Point Comfort (milepoint 0), there
were a number of large waste discharges. As a result of the strength of the tidal
(a)
(b)
(c)
(d)
I
s_x
o
Q
16
12
10
o>
O
O
o>
^»x
o
o
4
2
0
110
16
14
12
10
8
6
4
2
0
110
16
14
12
10
8
6
4
2
0
110
16
14
12
10
8
6
4
2
0
i Q; =
Jx *
i 1 *
§
° °«B 0
•
a: ?
£ 1
'E 1
-S *
g •
*
June 1971
m
1
£
0 5
100 90 80 70 60 50 40 30 20
10
Figure 9-7
Spatial distribution of DO
for the James estuary
(a) June 1971, (b)
September 1971, (c) July
1976, and (d) July 1983.
Sources: HydroQual, 1986;
Q Lung, 1986; Lung and
September 1971
100 90 80 70 60 50 40 30 20 10 0
July 1976
I I
100 90 80 70 60 50 40 30 20 10 0
•^..i i*
July 1983
110 100 90 80 70 60 50 40 30 20 10 0
River Miles from Mouth
Testerman, 1989.
9-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
action combined with the massive amount of dilution water available, a rather
steady DO level was measured. The DO levels seldom fell below 5.5 mg/L under
the worst conditions, and the depression of DO due to waste stabilization by
biological oxidation was usually less than 1 mg/L (Engineering Science, 1974).
The second survey in Figure 9-7 was conducted in September 1971, show-
ing even lower DO concentrations below Richmond, compared with the data from
the June 1971 survey. The DO sag was below 4 mg/L near milepoint 89, which
was followed by a slow recovery. Also shown in Figure 9-7 is the DO profile
measured in July 1976. The DO sag level (below Richmond) improved slightly
from the 1971 condition although the sag was still below 5 mg/L. A mild recovery
occurred until the wastes from the Hopewell area entered the river and depressed
the DO concentration again, resulting in a second DO sag in the river. Such a
two-sag DO profile has been consistently observed since the late 1970s. The low
DO gradually increased downstream for a full recovery.
The DO condition observed in July 1983 is also presented in Figure 9-7.
With continuing treatment upgrades beyond the secondary treatment for carbon
removal, the DO condition in the James estuary continued to improve in the
1980s. The data indicate that the minimum DO level was above 6 mg/L in
September 1983, a sign of continuing improvement of the water quality. The
impact from the Richmond area discharges has been significantly reduced
following the treatment plant upgrades.
Although the reduction of BOD5 loads from the POTWs was measured in
the last 20 years, no appreciable reduction of nutrient loads was detected until the
phosphate detergent ban in 1988. Prior to the Virginia phosphate detergent ban,
Lung (1986) conducted a modeling study assessing the water quality benefit of
point source phosphorus control in the James River basin. The model results are
summarized in Figure 9-8, showing the peak phytoplankton chlorophyll levels
predicted in the upper James estuary for various control alternatives ranging from
a phosphate detergent ban to phosphorus removal. The model suggests that the
reduction of chlorophyll in the water column due to the phosphate detergent ban
would be minimal while phosphorus removal at POTWs would offer reasonable
reductions in phytoplankton biomass in the upper estuary.
Figure 9-8
Projected impact of point
source phosphorus
controls.
Source: Lung and
Testerman, 1989.
IUU
X"-N
"oiSO
Y 60
1 40
o
Q.
n
Present Loads
P
D
laeph
stergi
1 15% Load Reduction
d
sn
:e
t Bans
25% Load Reduction
Phosphorus Removal
1
? rMi
Control Alternative
9-10
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Chapter 9: James Estuary Case Study
Evaluation of Water Quality Benefits
Following Treatment Plant Upgrades
From a policy and planning perspective, the central question in water
pollution control is simply Would water quality standards be attained if primary
treatment levels were considered acceptable? In addition to the qualitative
assessment of historical data, water quality models can provide a quantitative
approach to judge improvements in water quality achieved as a result of upgrades
in wastewater treatment. The James River Model (JMSRV), originally developed
by Hydroscience (1980) and subsequently enhanced by HydroQual (1986), Lung
(1986), and Lung and Testerman (1989), and calibrated using data for September
1983 conditions (Figure 9-9), has been used to demonstrate the water quality
benefits attained by the secondary treatment requirement of the 1972 CWA
25
f«
O
00 ,
o 5
0.5
<0.4
0.
00.2
"c
§•0.1
O
0 I —-H .—i . , 1 • i 1 1 0.0 .__....
110 TOO 90 80 70 60 50 40 30 20 TO 0 1TO TOO 90 80 70 60 50 40 30 20 TO 0
2.0 i • > •—i 1 •—• . 1 —, 0.5
2
I
*e
r
J.0.3
Q.
I 0.2
O
I0'1
0.0 '—H—'—<—i 1—i—i i i—i—I 0.0
110 100 90 80 70 60 50 40 30 20 TO 0 1
100 90 80 70 60 50 40 30 20 10 0
2.0
!0.5
0.0
50
O 30
| 20
o
| TO
6 „
1.5
110 TOO 90 80 70 60 50 40 30 20 TO 0 1TO 100 90 80 70 60 50 40 30 20 10 0
12
TO
? 8
1.0
0.5
"0.0
>§ 6
8 41
2
110 TOO 90 80 70 60 50 40 30 20 TO 0 1 TO TOO 90 80 70 60 50 40 30 20 TO 0
River Miles from Mouth River Miles from Mouth
Legend: } Observed Data (Avg. and Range) Model Results
Figure 9-9
James River model
calibrations for September
1983.
Source: Lung, 1991.
9-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
(Lung, 1991). Using the model, existing population and wastewater flow data (ca.
1983) were used to compare water quality for summer low-flow and 7Q10 low-
flow conditions simulated with three management scenarios: (1) primary effluent,
(2) secondary effluent, and (3) existing wastewater loading. Water quality condi-
tions for these alternatives were simulated using freshwater and wastewater flow
data for 1983, a year characterized by 66 percent of the summer average flow
(see Figure 9-3) of the James River (Figure 9-10).
Using the primary effluent assumption, under summer low-flow conditions,
water quality is noticeably deteriorated in comparison to the 1983 calibration
results. DO concentrations downstream of Richmond (RM 90) are computed to
be near zero under the primary scenario. Using the secondary assumption, the
significant reduction in BOD5 loading significantly improves DO between Rich-
mond and Hopewell, Virginia. In comparison to the primary scenario, minimum
Figure 9-10
Comparison of simulated
impact of primary,
secondary and existing
1983 effluent levels on DO:
(a) summer 1983
conditions and (b) 7Q10
low-flow conditions.
Source: Lung, 1991.
(a)
(b)
12
11
10
j 9
x.
E 8
«^_^
I ?
I" 6
o
"I 4
en
•- T
Q 3
2
1
O
-o 5
1983 Loads
Secondary Treatment
Primary Treatment
110 100 90 80 70 60 50 40 30 20 10
River Miles from Mouth
1983 Loads
Secondary Treatment
Primary Treatment
110 100 90 80 70 60 50 40 30 20 10
River Miles from Mouth
9-12
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Chapter 9: James Estuary Case Study
monthly averaged oxygen levels increase to almost 3.5 mg/L from less than 0.5
mg/L under the secondary effluent scenario. As shown with both observed data
(Figure 9-9) and state-of-the-art model simulations (Figure 9-10), the implementa-
tion of secondary and better treatment has resulted in significant improvements in
the DO status of the estuary.
As demonstrated with the model, better-than-secondary treatment is re-
quired to achieve compliance with the water quality standard of 5 mg/L under
extreme 7Q10 low-flow conditions (Figure 9-10) for DO downstream of Rich-
mond. In contrast to the 1950s and 1960s, the occurrence of low-oxygen condi-
tions has been virtually eliminated within the upper James River estuary. Addi-
tional improvements in water quality, in terms of reduced algal biomass and still
greater improvements in DO levels, have been achieved as a result of advanced
secondary levels of wastewater treatment for the Upper James River.
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
Upgrades of wastewater treatment plants to secondary treatment in the
1970s and continued commitment to water quality-based pollution controls
throughout the 1980s and 1990s have achieved a dramatic recovery for the James
River. Instead of turkey vultures, residents of Richmond currently gaze at blue
herons, bald eagles, and ospreys as they circle overhead (Epes, 1992). Although
passage of the Clean Water Act in 1972 was the most significant factor contribut-
ing to the comeback of the James, other factors contributing to improvements in
wildlife habitat included the creation of a flood control reservoir in the early 1980s
to stabilize flow, the ban of the insecticide DDT, and floods and hurricanes in the
1960s and 1970s.
The ban on DDT allowed certain birds affected by egg shell thinning,
including eagles and ospreys, to recover. The floods and hurricanes contributed to
habitat improvement by punching holes in several of the dams in the river, allow-
ing migrating fish to pass through once more (Epes, 1992). Those holes and
subsequent man-made fish ladders have allowed fish to swim farther upstream to
spawn again.
Above the falls, the return of smallmouth bass has made the upper James
one of the best smallmouth bass fisheries in the country. Below Richmond,
abundant largemouth bass attract the national Bassmasters fishing tournaments.
Striped bass, an anadromous (saltwater-to-freshwater migrating) fish, has re-
turned to the James due in part to a state harvesting moratorium in effect for
several years in the Chesapeake Bay. In fact, a 25-pound striped bass was caught
in 1992 near Williams Dam in Richmond (Epes, 1992).
Fish-eating birds have also recently returned to the James. In the 1970s
there were no bald eagles or ospreys nesting on the James River. In 1992 three
pairs of bald eagles and six pairs of ospreys had reclaimed their historical nesting
sites on the James (Bradshaw, 1992). Great blue herons boast about 200 pairs
(Bradshaw, 1992). Birds began to return in the mid-1980s (Table 9-3). Cattle
egrets and double-crested cormorants extended their ranges to colonize the James
9-13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
possibly due to reduction in available habitat elsewhere. In 1992, there were about
250 pairs of each overwintering in the region from Richmond to the Benjamin
Harris bridge (Bradshaw, 1992). Cattle egrets eat reptiles and eels, and double-
crested cormorants eat fish. These birds are no doubt responding to the increase
in the stream quality for fish and other aquatic life now that organic and nutrient
loads to the James have been controlled.
Summary and Conclusions
An analysis of the existing water quality data for the James River estuary
has been conducted to document the historical changes in waste loads and the
water quality improvement in the estuary from 1971 to the mid-1990s. The latest
water quality model for the upper James estuary was modified to include the
lower portion of the estuary. This modified model was calibrated and verified
using three sets of water quality data. Finally, the verified model was used to
evaluate the water quality improvement due to the treatment upgrades from
primary to secondary at the POTWs. Altogether, six simulation scenarios, incor-
porating different ambient environmental conditions and waste load levels, were
developed for evaluation.
The analysis of POTW waste loads indicated significant reduction of BOD5
discharged into the James estuary starting in the early 1970s. By the mid-1980s,
many POTWs had achieved high degrees of carbon removal with treatment
levels beyond secondary. Nutrient reduction did not start until 1988, when the
phosphate detergent ban became effective.
A review of the historical water quality data showed the improvement of
DO conditions in the James estuary from a DO sag of much lower than 5 mg/L in
1971 to levels consistently above 5 mg/L in the 1980s. Nutrient concentrations in
the water column of the James estuary have remained quite stable over the past
20 years. The model results showed a clear, progressive rise in DO levels in the
estuary from primary treatment to secondary treatment, and to treatment beyond
secondary at the POTWs. Based on the analyses of historical waste load data,
water quality data, and model results, it can be concluded that the treatment
upgrades from primary to secondary and better levels of treatment at POTWs
provided significant water quality improvement in the James River basin. With the
cleanup of the James River, visitors to Richmond, Virginia, can enjoy a riverboat
dinner cruise or a stroll along the refurbished 2-mile canal walk. More adventur-
ous visitors can challenge themselves by rafting and kayaking on the only Class
IV white water located in an urban river in the country (McCulley, 1999). Birds
and fish are also making a remarkable recovery in the James River basin in
response to water quality improvements.
9-14
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Chapter 9: James Estuary Case Study
References
Bradshaw, Dana. 1992. Virginia Department of Game and Inland Fisheries.
Personal communication, November 4, 1992.
Engineering Science. 1974. Lower James River basin comprehensive water
quality management plan. Planning Bulletin 217-B. Final report prepared
for Virginia State Water Control Board by Engineering Science Co.
Epes, C. 1992, June 15. Honk if you spot a brown pelican. Richmond Times-
Dispatch. Richmond, VA.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to
1990. U.S. Bureau of the Census, Population Division, Washington, DC.
.
HydroQual, Inc. 1986. Water quality analysis of the James and Appomattox
Rivers. Report prepared for Richmond Regional Planning District Commis-
sion. June.
Hydroscience, Inc. 1980. Water quality analysis of the upper James River
estuary. Report prepared for Virginia Water Control Board. April.
Lung, W.S. 1986. Assessing phosphorus control in the James River basin. Jour.
Envir. Eng., ASCE 112(1): 44-60.
Lung, W.S. 1991. Trends in BOD/DO modeling for wasteload allocations of
the James River estuary. Technical memorandum prepared under sub-
contract for Tetra Tech, Inc., Fairfax, VA, by Envirotech, Inc.,
Charlottesville, VA.
Lung, W.S., and N. Testerman. 1989. Modeling fate and transport of nutrients in
the James estuary. J. Envir. Eng., ASCE 115(5): 978-991.
McCulley, C. 1999, October 17. Rapids transit. The Sun. Section R. Baltimore,
MD.
OMB. 1995. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
Richmond News Leader. 1963, October 8. Neglected asset: the James.
Richmond Times-Dispatch. 1992. Editorial.
SWCB. 1982. Upper James River estuary wasteload allocation plan. Final
report prepared for Richmond Regional Planning District Commission by
Virginia State Water Control Board, Richmond, VA.
USDOC. 1998. Census of population and housing. U.S. Department of
Commerce, Economics and Statistics Administration, Bureau of the Census -
Population Division, Washington, DC.
USEPA (STORET). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
Watersheds, Washington, DC.
USGS. 1999. Streamflow data downloaded from the U.S. Geological Survey's
National Water Information System (NWIS)-W Data retrieval for historical
streamflow daily values, .
9-15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
9-16
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Chapter 10
Upper
Chattahoochee
River Case
Study
The Southeast Basin (Hydrologic Region
3), covering a drainage area of 278,523 square
miles, includes the Chattahoochee-Flint-Apalachicola
River, which has a length of 524 miles and a drainage
area of 19,600 square miles (Iseri and Langbein, 1974).
On the basis of a mean annual discharge (1941-1970) of
24,700 cfs, the Chattahoochee-Flint-Apalachicola River ranks
23rd of the large rivers of the United States (Iseri and Langbein,
1974). Figure 10-1 highlights the location of the Upper Chattahoochee
River case study watersheds (catalog units) and the city of Atlanta,
Georgia, identified in this river basin as one of the urban-industrial
waterways affected by severe water pollution problems during the
1950s and 1960s (see Table 4-2). In this chapter, information is pre-
sented to characterize long-term trends in population, municipal wastewa-
ter infrastructure and effluent loading of pollutants, ambient water quality,
environmental resources, and uses of the Upper Chattahoochee
River. Data sources include USEPA's national water quality data-
base (STORET), published technical literature, and unpublished
technical reports ("grey" literature) obtained from local agency
sources.
The Chattahoochee River Basin constitutes almost 40 percent
of the Chattahoochee-Flmt-Apalachicola River Basin (Figure 10-2),
which discharges into the Gulf of Mexico. The Chattahoochee River
flows from northeast Georgia through metropolitan Atlanta to West
Point Dam. From there the river forms the Georgia-Alabama border
and, for a short distance, the Georgia-Florida border. Near the
southern border of Georgia the Flint River joins the Chattahoochee
River to form the Apalachicola River. Major urban centers in the
Figure 10-1
Hydrologic Region 3 and
the Chattahoochee-Flint-
Apalachicola River Basin.
10-1
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 10-2
Location map of Upper
Chattahoochee Basin.
River miles shown are
distances from Gulf of
Mexico.
85°30'
34°00'
32°30'
40 Miles
34°00'
32°30'
85°30'
84°00'
Upper Chattahoochee River Basin include Atlanta, Gainesville, Marietta, Cornelia,
and Alpharetta, Georgia. The Atlanta region represents only 3.6 percent of
Georgia's total land area but contains one-third of the state's population (ARC,
1984). The large volume of wastewater discharged in the Atlanta area has a far-
reaching effect on water quality conditions in receiving waters. The Upper
Chattahoochee River is by far the largest river in the Atlanta region. Other streams
in the region include Sweetwater Creek, South River, Flint River, Yellow River,
Peachtree Creek, and Line Creek.
The Chattahoochee River is Atlanta's major water supply source and
receptacle for wastewater disposal. The Upper Chattahoochee River Basin
provides numerous recreational areas and fish and wildlife habitats. Lake Sidney
Lanier, for example, is a nationally popular water resort area. The area from
Buford Dam to Peachtree Creek has been under intensive development pressures
that threaten the water quality of the Chattahoochee River.
Physical Setting and Hydrology
The Upper Chattahoochee River Basin covers 10,130 square miles from the
southern slopes of the Blue Ridge mountains, in northeast Georgia, to the West
Point Dam at the Georgia-Alabama state line. The flow length of this section is 250
river miles, generally to the southwest. The basin is narrow in relation to its length,
the average width being less than 40 miles. Elevations in the Upper Chattahoochee
10-2
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Chapter 10: Upper Chattahoochee River Case Study
Basin range from approximately 4,000 feet at the headwaters to approximately 635
feet at West Point Lake. Air temperature tends to be cooler in the mountains and
wanner in the southern areas of the basin; the annual air temperature averages
about 16 °C. Average annual rainfall in the basin is about 54 inches over the basin
area of 3,440 square miles. The rainfall tends to be greatest in upland areas and in
the southern region of the basin (Cherry et al., 1980; Lium et al., 1979).
Flow in the river is dependent on rainfall and regulation by the hydroelectric
generating facilities at Buford Dam and Morgan Falls Dam. High-flow conditions
usually occur in the spring and low-flow conditions in late autumn (Figure 10-3).
The most pronounced changes in regulated flow have occurred as a result of the
construction and operation of the Buford Dam since 1957. In the mid-1960s, the
city of Atlanta and the Georgia Power Company modified the Morgan Falls Dam
and Reservoir, just upstream of Atlanta, to provide a minimum flow of 750 cfs
from Morgan Falls. Since 1965 minimum streamflows have been higher and more
consistent as a result of those modifications (Figure 10-4). The average flow at
Figure 10-3
Monthly trends in
streamflow for the
Chattahoochee River.
Monthly mean, 10th, and
90th percentile statistics
computed for 1951-1980
(USGS Gage #02336000
at Atlanta, Georgia).
Source: USGS, 1999.
ONDJ FMAMJ JAS
10000
•e
Figure 10-4
Long-term trends in mean,
10th, and 90th percentile
statistics computed for
summer (July-Septem-ber)
streamflow for the
Chattahoochee River
(USGS Gage #02336000
at Atlanta, Georgia).
Source: USGS, 1999.
1950
1960
1970
1980
1990
-- 90%ile
mean & ratio
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table 10-1. Metropolitan Statistical Area (MSA) counties in the Upper
Chattahoochee Basin case study. Source: OMB, 1999.
Barrow
Bartow
Carroll
Cherokee
Clayton
Cobb
Coweta
DeKalb
Douglas
Fayette
Forsyth
Fulton
Gwinnett
Henry
Newton
Paulding
Pickens
Rockdale
Spalding
Walton
Buford Dam, based on 35 years of record, is 2,168 cfs. The average flow near
Atlanta, based on 43 years of record, is 2,603 cfs. Regulations for minimum
streamflow volumes set in 1974 require a minimum release of 1,100 cfs from
Morgan Falls, further increasing minimum streamflows near Atlanta (Cherry et
al, 1980; Liumetal., 1979).
Population, Water, and Land Use Trends
The Upper Chattahoochee River case study area includes several counties
that are defined by the Office of Management and Budget as Metropolitan
Statistical Areas (MSAs) or Primary Metropolitan Statistical Areas (PMSAs).
Table 10-1 lists the MS A and counties included in this case study. Figure 10-5
presents long-term population trends (1940-1996) for the counties listed in Table
10-1.
From 1940 to 1996 the population in the Upper Chattahoochee River case
study area increased dramatically (rising from 0.41 million in 1940 to 3.53 million
in 1996). The U.S. Bureau of the Census reported the 1970 population of the
Figure 10-5
Long-term trends in
population in the Upper
Chattahoochee River
basin.
Sources: Forstall, 1995;
USDOC, 1998.
1940 1950 1960 1970 1980 1990 1996
10-4
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Chapter 10: Upper Chattahoochee River Case Study
Atlanta area to be 1.7 million. By 1990 this number had risen to 2.95 million
(Forstall, 1995; USDOC, 1998). During the 1950s through the 1970s, population in
the Atlanta region increased by 34 percent to 39 percent; the greatest growth
rates were recorded in 1950-1960 (39 percent) and 1970-1980 (38 percent).
During the 1980s and 1990s, the rate of growth slowed down considerably: the
population increased by 22 percent from 1980 to 1990 and by only 19 percent
from 1990 to 1996 (Forstall, 1995; USDOC, 1998). During the 1970s, population
density in the area varied by about an order of magnitude from approximately 40
persons per square mile in the rural, headwater areas of the basin to 492 persons
per square mile in the urban environs of Atlanta (Faye et al., 1980).
Land in the Upper Chattahoochee Basin, upstream and downstream of
Atlanta, is predominantly forest. The Atlanta area of the basin is predominantly
residential. Agricultural activity is fairly evenly distributed through the basin. Table
10-2 shows the major land uses in the basin (Cherry et al., 1980; Lium et al.,
1979; Stamer et al., 1979). Agricultural activities above the Buford Dam are
concentrated in stream valleys and on the lower slopes. Crops and pastures
occupy a significant portion of the agricultural areas, but poultry operations are
the economically dominant agricultural activity. Urban areas are predominantly
residential, but industrial activities are significant. Industrial activities include
automobile assembly, food processing, and light manufacturing. Intense industrial
land use dominates the area downstream of Interstate Highway 75 (Mauldin and
McCollum, 1992).
Power generation, water supply, water-quality maintenance, and recreation
are activities currently supported along the Chattahoochee River. Six power-
generating facilities use the resources of the Chattahoochee River. The Buford
Dam and Morgan Falls Dam are peak-power hydroelectric generating facilities.
The other four are fossil-fuel thermoelectric power plants. The six plants have a
combined generating capacity of approximately 3.8 million kilowatts. Two fossil-
fuel plants near Atlanta discharge nearly 1000 cfs of cooling water to the river.
As of 1998, 29 public water treatment plants process water withdrawn from
rivers and lakes in the Atlanta region and 3 new treatment facilities were proposed
for the Atlanta area. The largest water treatment plants in the region are operated
by the city of Atlanta (Hemphill & Chattahoochee, design capacity 201 mgd),
Dekalb County (Scott Candler, 128 mgd), Gwinnett County (Lake Lanier, 120 mgd),
and Atlanta-Fulton County (Atlanta-Fulton County, 90 mgd). The Chattahoochee
River and Lake Lanier are their main sources of raw water. The total capacity of
Table 10-2. Land use in the Upper Chattahoochee River Basin.
Area I Percentage Breakd
Location (mi2) Urban Agriculture
Above Buford Dam
Buford Dam - Atlanta
Atlanta - Fairburn
Fairburn - Whitesburg
Whitesburg - West Point Dam
1,040
410
610
370
1010
4
22
40
6
4
16
18
12
17
17
Forest
81
60
49
77
79
10-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
the public water supply withdrawals from the 14 largest water treatment plants is
770.5 mgd (ARC, 1998). As of the late 1990s, approximately 443 mgd was with-
drawn from water sources in the Upper Chattahoochee, primarily from surface
water sources (ARC, 1998). During the mid-1970s, water use was estimated at 180
mgd with an increase in demand to 484 mgd fairly accurately projected for the year
2000 (Lium et al., 1979). Providing about 85 percent of the region's water supply,
the Chattahoochee River and Lake Lanier system and the Etowah River and
Allatoona Lake system are the most important sources of public water. As of the
late 1990s, residential and commercial water uses accounted for 54 percent and 23
percent of the total water demand, respectively. Government activities accounted
for 6 percent and manufacturing uses for only 4 percent; approximately 14 percent
could not be accounted for (Kundell and DeMeo, 1999). By the year 2020, regional
water demand is expected to increase by approximately 46 percent of the with-
drawals ca. 1998. The projected increase in water demand and the limited availabil-
ity of surface water and ground water supply sources in northern Georgia are a key
factor in the need for regional cooperation to meet the challenges posed by water
supply and water quality problems in the Atlanta region (Kundell and DeMeo,
1999).
Water-based recreational activities are abundant all along the
Chattahoochee River. The headwaters are popular for trout fishing, camping, and
hunting. Lake Sidney Lanier maintains numerous boat launches, campgrounds,
marinas, yacht clubs, and cottages. The reach from Buford Dam to Atlanta
supports fishing, canoeing, and rafting. The reach between Morgan Falls and
Peachtree Creek, one of the most scenic on the river, is the site for an annual raft
race that draws thousands of participants and onlookers to the area. West Point
Lake, at the base of the Upper Chattahoochee River Basin, is an impoundment
created by the construction of West Point Dam in 1974. This lake is widely used
for fishing, boating, camping, and swimming.
Historical Water Quality Issues
The poet Sidney Lanier, who praised the Chattahoochee in his "Song of the
Chattahoochee," would not have been so inspired during the 1940s, 1950s, and
1960s. The Chattahoochee River was characterized by poor water quality for a
reach of 70 miles below Atlanta. The first 40 miles were described as "grossly
polluted," and responsibility was attributed to inadequately treated wastewater,
particularly from Atlanta's R.M. Clayton sewage treatment plant, at the mouth of
Peachtree Creek (EPD, 1981). Figure 10-6 shows the effect Atlanta's wastewater
discharges historically have had on the water quality of the Chattahoochee River,
with DO levels drastically depleted downstream of Atlanta near SR-92 (RM 280).
At Fairburn, an average of 13 percent of the river flow consisted of wastewater
(Stamer et al., 1979). From July through October heat and low flow placed the river
in near septic conditions, with DO below 4 mg/L 64 percent of the time. During the
period from 1968 to 1974, DO concentrations were 64 percent less in the summer
months than in January and minimum DO levels were consistently below 1 mg/L
(EPD, 1981). In 1973 DO concentrations dropped to zero during September. As of
1972 the R.M. Clayton plant was still releasing large quantities of wastewater
receiving only primary treatment. Fecal coliform densities, ammonia, BOD5, and
10-6
-------
Chapter 10: Upper Chattahoochee River Case Study
Dissolved Oxygen (mg/L)
3 K> *» O) CX) C
„*-,
."...«-.?:<
8
**•!
•-S^HHTV1^"
f.ajr3. >****.'
¥ .
. ' - -A_.
I,V',
/ 1
^ : Seconder
;"!/
t**..* .;'...
Atlanta Water Intake
' RM 299.3
SR92 R
k Campbel
/ Treatment
A 280.3
on Ferry
On-line
Figure 10-6
Long-term trends of DO
concentration upstream
and downstream of Atlanta
wastewater discharges.
Source: EPD, 1981.
1960 1965 1970 1975 1980 1985 1990
Intake /Avg
RM 280 /Avg - a- - Intake /Mm -* • RM 280 /Win
suspended solids concentrations continued to be high above and below the discharge
at Peachtree Creek. Fish kills caused by discharges of raw sanitary sewage and
industrial chemicals were commonplace before 1976 (Mauldin and McCollum,
1992).
Rainfall in the area results in overflows from combined sewer systems
(CSOs) and large amounts of urban runoff, contributing to large dissolved and
suspended constituent loads to the river. Twelve CSOs have been identified in the
watershed (Mauldin and McCollum, 1992). Low-flow periods result in less dilution
of wastewater, resulting in low DO concentrations, high BOD5, high fecal
coliform densities, and other problems.
A severe drought in 1988 caused the DO level to dip below 4 mg/L in the
study region from April to August (Mauldin and McCollum, 1992). A major fish
kill occurred during October of 1988 due to an unidentified agent (Mauldin and
McCollum, 1992). The many impoundments along the river and releases of
cooling water from fossil fuel plants, in excess of 1,000 cfs, contribute to water
temperature increases, further reducing the waste assimilation capabilities of the
river. Atlanta's population is served by 27 water pollution control plants, with
designated flows greater than 0.01 mgd, located along the river and its tributaries.
The 12 largest water pollution control plants in the Atlanta region have a total
design capacity of 404 mgd. The largest facility, the R.M. Clayton plant, is
operated by the city of Atlanta and has a capacity of 120 mgd. More than half of
the total volume of wastewater enters the river near river mile 301 downstream
of the city of Atlanta's water intake (Mauldin and McCollum, 1992).
Legislative and Regulatory History
Concern for the coordination of water and sewer facility planning and
operation has existed in Atlanta since the early 1930s. Construction of the metro-
politan sewer system began in 1944 as a cooperative effort between Atlanta local
governments. From 1950 to 1952 a major functional consolidation, The Plan of
Improvement, was prepared to better define service functions between the city of
Atlanta and Fulton County. Atlanta was the primary provider of sewage treatment
at that time. During the 1960s the near septic conditions in the river concerned
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Progress In Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
many people. Utility of the waters was greatly reduced, threatening water
supplies, recreation, and aquatic habitats. Studies were conducted to identify
problems and needs. Technology was available to remedy many of the problems
identified, but funding was unavailable.
The Georgia Water Quality Control Act (enacted 1964, amended) was the
first major state law to be applied to water quality management. The act gives the
Georgia Environmental Protection Division (EPD) power to control all types of
pollution in the state's waters from both point and nonpoint sources. In the late
1960s the Atlanta Region Metropolitan Planning Commission (now the Atlanta
Regional Commission or ARC) prepared several reports on the consolidation of
water and sewer services. The Preliminary Water and Sewer Report, issued in
1968, provided elements of an Administrative Plan for water and sewers in the
Atlanta region. The report called for a basinwide water/sewer authority, represent-
ing nine counties, to oversee water quality management on a basinwide scale.
Unfortunately, local officials did not support the plan because of the large esti-
mated cost (Hammer et al., 1975).
The next state-level move toward regulation was the Metropolitan River
Protection Act (MRPA) (enacted 1973, amended), which allows the ARC to
advise local governments when proposed developments violate the Chattahoochee
Corridor Plan. The plan establishes standards for development based on the
carrying capacity of the land within 2,000 feet of impoundments or riverbank of
the Chattahoochee or within the 100-year floodplain, whichever is greater (ARC,
1984). The Soil Erosion Act of 1975 also created controls over the effects of
development in the area. This act requires local counties and municipalities to
adopt and enforce local ordinances to control soil erosion from land-disturbing
activities within their jurisdiction.
The 1972 CWA resulted in significant improvement of the water quality in the
Upper Chattahoochee River Basin. Funding was provided under the CWA in the
form of the Construction Grants Program. The state of Georgia received $117
million in 1976 under this program, but funding decreased steadily. Only $41 million
was provided in 1983, despite the fact that Georgia reported needs of $300 million in
1983 (Lawler et al., 1989). Beginning in 1988 funding for the Construction Grants
Program was reallocated to the State Revolving Fund (SRF) as a mechanism for
providing financial assistance to municipalities. The CWA established secondary
treatment as the minimum allowable level for municipal plants. The National
Pollutant Discharge Elimination System (NPDES), a national permit program that
regulates polluted discharges and requires permittees to monitor effluent quality, is
also included in the CWA. States were called upon to develop water quality stan-
dards, water use classification, and effluent limits based on water quality criteria
established by USEPA.
Attempts were made to improve water quality in the Chattahoochee River
by regulating flow. The EPD set requirements for minimum flow of 750 cfs
upstream of Atlanta (Cherry et al., 1980). A regulatory dam downstream from
Buford Dam has been proposed and modeled. The dam would ensure Atlanta's
water supply into the 21st century and aid in regulating river flow. The require-
ment for minimum releases from Buford Dam would be eliminated. It is not
possible to greatly affect flow since there is a limited amount of water available
and water supply demands and wastewater flows continue to increase.
10-8
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Chapter 10: Upper Chattahoochee River Case Study
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
Major improvements in water quality occurred in the Chattahoochee Basin
during the 1970s and early 1980s, resulting from implementation of secondary
treatment. The effects of the increasing load of wastewater were diminished by
better treatment technology. Figure 10-7 shows the increasing trends of effluent
discharge rates for the area's larger wastewater treatment plants. By 1974 all
Atlanta-area waste treatment facilities had been upgraded to provide secondary
levels of treatment. Before implementation of secondary treatment, DO levels
were severely reduced by wastewater discharges from Atlanta (Figure 10-8).
Figures 10-6 and 10-8 show dramatic improvements beginning in 1974. The
D
03
§
Figure 10-7
Long-term trends of
wastewater flow for major
wastewater treatment
plants in the Atlanta area.
Sources: ARC, 1984;
USEPA, 1971; USPHS,
1963; Woodward, 1949;
Richards, 1999.
1950
1960
1970
1980
1990
2000
South R & Intrench -«- R.M. Clayton -a- - Utoy Creek
1950 1960 1970 ' 1980
River Mile 280-290 near Atlanta GA
1990
Figure 10-8
Long-term trends of mean,
minimum, and maximum
summer DO in the
Chattahoochee River near
Atlanta, Georgia (RF1-
03130002066) (mile 280-
290).
Source: USEPA (STORET).
Mean Mm Max
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
effects of secondary treatment on DO concentrations are particularly notable
during the summer months (Figure 10-9). Water quality has improved despite a
doubling of Atlanta's population over the period from 1970 to 1996 (Figure 10-5).
Many advances in improving water quality since 1974 can be attributed to
continually improving operation and maintenance procedures. Figure 10-10
indicates improvements in suspended solids concentrations and BOD5 in the
effluent waste water from the R.M. Clayton plant, the largest in the Atlanta
region. These improvements resulted primarily from improved operator training
and upgrading of the solids-handling facility. Similar changes took place at other
area plants during this time. The R.M. Clayton plant operated at a primary level
of treatment from the late 1930s to the mid-1960s. For much of this time the
capacity of the plant exceeded the design flow and treatment was below design
level. When the plant was upgraded to provide secondary treatment, around 1968,
the design flow was also increased to 120 mgd. A portion of the wastewater flow
continued to receive only primary treatment into the early 1970s, when further
Figure 10-9
Comparison of January
and July mean dissolved
oxygen below Atlanta
wastewater discharges
before and after upgrade to
secondary treatment.
Source: EPD, 1981.
January
Before: 1964-68 r After. 1975-80
Figure 10-10
Performance of the
R.M. Clayton
wastewater treatment
plant.
Sources: ARC, 1984;
USEPA, 1971; USPHS,
Q
1970 ' ' 1975 ' ' 1980 ' ' 1985 1990 1995 2000
—- NH3-N -A
• TSS
10-10
-------
Chapter 10: Upper Chattahoochee River Case Study
improvements were made. In 1974 the R.M. Clayton Plant was providing second-
ary treatment to 100 percent of the plant's wastewater flow. In the early 1980s
operating and maintenance improvements further lowered BOD5 concentration in
the effluent wastewater. The R.M. Clayton plant was upgraded to advanced
secondary with ammonia removal in 1988. By December 2000, the R.M. Clayton
plant, the Utoy plant, and the South River plant will have state-of-the-art effluent
filters, biological phosphorus removal, ultraviolet disinfection, and new headworks
(Richards, 1999). Decreases in the BOD5 loading of effluent at the R.M. Clayton
Plant as a result of upgrading levels of treatment are shown in Figure 10-11.
All of the larger wastewater treatment plants in the Atlanta region must
meet treatment requirements more stringent than secondary treatment. Phospho-
rus removal and restrictions on phosphates in detergents, for example, have
resulted in a decline of ambient phosphorus concentrations downstream of Atlanta
from approximately 1.0-1.2 mg/L in the early 1980s to approximately 0.1 mg/L a
decade later (ARC, 1998). Land application of treated wastewater is also being
used at several facilities in the region, with treated wastewater sprayed on
forestland, golf courses, or other landscaped areas. At the 4,000-acre E.L. Huie
Land Application site, the Clayton Water Authority operates the largest site,
treating 18 mgd by reclaiming the treated effluent for its water supply since the
water percolates through the soil and back to the raw water source (ARC, 1998).
A combined sewer system, originally constructed in Atlanta ca. 1900-1940,
has historically contributed to water pollution in the Chattahoochee River. State
legislation adopted in 1990 required the elimination or control of the CSO system.
As of 1998, 7 of the 10 CSOs in Atlanta were associated with wastewater
treatment plants for solids removal and disinfection. Two sites had been com-
pletely eliminated by separation of storm water and sewage collection systems,
and additional projects were planned to continue the separation of storm water
and sanitary sewage (e.g., Utoy Creek sewage separation project).
125
Figure 10-11
Long-term trends of
effluent BOD5 for the R.M.
Clayton wastewater treat-
ment plant. Data for calcu-
lated BOD5 based on efflu-
ent flow data, 200 mg/L
influent BOD5, and removal
rates of 35 percent
(primary), 85 percent
(secondary), and 95
percent (tertiary).
Sources: ARC, 1984;
USEPA, 1971; USPHS,
1963; Woodward, 1949,
Richards, 1999.
Estimated Load
Load
-»• Concentration
10-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
Historical records offish population in the Chattahoochee River below
Atlanta are very limited. Conditions downstream of Atlanta's wastewater
discharge were unsuitable for fish survival during the 1970s, and no fish surveys
could be collected (Mauldin and McCollum, 1992). Shelton and Davies (1975)
conducted a preimpoundment survey of the area to be flooded by the West Point
Dam. The survey lasted from January 1972 to May 1974. The station closest to
Atlanta on the Chattahoochee was at Franklin, Georgia. During the early 1970s
study period, the Chattahoochee River was described as carrying a high organic
load from municipal wastes, a high suspended solids load from agricultural and
construction practices, and high chemical concentrations from industrial efflu-
ents. The relatively poor water quality in the Chattahoochee River affected the
distribution and abundance of fish species sampled in the main stem versus the
tributaries. Seventeen species of fish were collected in the Chattahoochee River
at Franklin, which is less than half the number of species expected for Georgia
rivers of similar size.
A fish survey of the Chattahoochee River conducted between July 1990
and June 1992 revealed the return offish in great numbers to the portion of the
river below the city of Atlanta. The number of species collected ranged from 14
or 15 at the sites in the direct vicinity of the wastewater treatment plant to 18 to
22 at the sampling sites located 63 and 23 km downstream, respectively. The
diverse species collected represented a considerable improvement from condi-
tions in the early 1970s, when only 17 species were sampled at Franklin, about
100 km downstream from the wastewater treatment plant, and no fish were
present downstream of Atlanta's water supply intake (Mauldin and McCollum,
1992). The recent survey collected 12 gamefish species compared to 8 collected
by Shelton and Davies (1975); the most abundant of game species by weight
were largemouth bass, bluegill, and channel catfish. Samples were analyzed
using the Index of Biotic Integrity (IBI) (Karr, 1981; Karr et al., 1986). IBI
scores for the four sampling sites (located 1 km upstream of the discharge, 1 km
downstream of the discharge, 23 km downstream, and 63 km downstream)
ranged from 22 to 32, which is 37 percent to 53 percent of the maximum score
of 60. Scores in the 21 to 30 range indicated poor stream quality for fish and a
population dominated by omnivorous, pollutant-tolerant forms. The
Chattahoochee River below Atlanta's wastewater treatment plant discharge had
a disproportionate segment of carp (75 percent), a higher proportion of bluegill to
redbreast sunfish than is common in Georgia streams, and fewer gamefish than
expected. A score of 32 measured 23 km downstream from the discharge
indicated fair stream quality for fish. Overall, the fish sampled appeared to be
healthy. Neoplasms were not observed in bluegill specimens, nor were gross
external abnormalities observed in catfish.
The results of the 1990 to 1992 sampling show that water quality has
improved immensely since 1972 when the river below Atlanta was described as
"in near septic condition for a reach of 35 miles" (GADNR, 1991). The improve-
10-12
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Chapter 10: Upper Chattahoochee River Case Study
Table 10-3. Fish kills due to municipal waste discharges in the greater Atlanta region. Source: Mauldin and
McCollum, 1992.
Location
Chattahoochee River, Atlanta
Proctor Creek, Atlanta
Chattahoochee River, Atlanta
Nancy Creek, Chamblee
Marsh Creek, Sandy Springs
Little Nancy Creek, Atlanta
Date of
occurrence
8/13/64
7/18/76
7/29/76
7/24/81
9/3/81
9/28/84
Duration
1 day
1 day
12 hours
12 hours
1 day
Unknown
Severity
Moderate
Moderate
Moderate
Severe
Moderate
Moderate
Length of
Stream
Affected
(miles)
6
5
15
3
1
1
Game
Species
(%)
70
3
75
87
37
63
ment is due to enhanced wastewater treatment (Mauldin and McCollum, 1992).
Combined efforts of the state, communities, and industries and USEPA grants for
municipal wastewater treatment systems have put the Upper Chattahoochee
River on the road to recovery. Fish kills have not been commonplace since 1976,
except for one caused by an unidentified agent in 1988 (Mauldin and McCollum,
1992) (Table 10-3). Bloodworm-infested sludge beds no longer float in the
shallows below Atlanta, sportfish populations are recovering, there is more DO in
the water, macroinvertebrate fauna is more diverse, and fecal coliform bacteria
levels dropped 82 percent in only 4 years (USEPA, 1980). The number of water
quality violations has dropped dramatically since the 1970s even though standards
have increased. Water-based and contact recreation are now fully supported
along the Chattahoochee River reach from Buford Dam to Peachtree Creek.
Fishing is generally supported along the entire river (GADNR, 1991). As a result
of the investments to upgrade water pollution control facilities in the Atlanta
metropolitan region, the natural ecological balance of the river is beginning to be
restored.
Summary and Conclusions
Results of legislation and regulations have been positive due to active
enforcement on all levels. Water quality monitoring by the EPD and under the
NPDES program helps to evaluate progress and indicate violations. Water quality
in the Upper Chattahoochee River, particularly in the vicinity of Atlanta, has
improved dramatically with implementation of secondary waste treatment.
Chemical, physical, and biological data all indicate a great improvement in water
quality when compared to data from investigations done in the 1940s, 1950s,
1960s, and 1970s (Lawler, Matusky, and Skelly Engineers, 1989). Although total
loading of pollutants to the Chattahoochee River, such as BOD5, suspended solids,
and phosphorus, have been reduced significantly as a result of major capital
improvements to the wastewater and water pollution control infrastructure of the
Atlanta region during the 1970s and 1980s, the dramatic improvements in water
10-13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
quality of the river tended to level out during the 1990s. Contemporary degrada-
tion of water quality is attributed to rapid urban development, the expanding area
of the outer suburbs of Atlanta, and nonpoint source loading from stormwater
runoff. The Georgia DNR listed more than 600 stream miles in the Atlanta area
as impaired in the 1994-1995 305(b) report, with less than 20 percent of the
degradation in stream miles attributed to point source pollution. As a result of
increased sediment loading from watershed runoff to the Chattahoochee River
and the reservoirs, water supply intakes are routinely shut down during and after
rainstorms. Contemporary water resource issues for Atlanta include the degrada-
tion of water quality in rivers and streams, the adverse impact of storm water
runoff on public water supplies and recreational lakes, and probable limits on
future water supply allocations under the tristate river compacts that have
sparked "water wars" between Georgia, Alabama, and Florida (Kundell and
DeMeo, 1999). Despite the successes of past water pollution control efforts
during the 1970s and 1980s, the Atlanta region is now confronted with serious
water supply and water quality issues that will affect the future economic viability
of the Atlanta metropolitan region. To achieve the solutions to contemporary
water quality problems required by state and federal agencies, regional coopera-
tion is needed for watershed management (Kundell and Demeo, 1999).
References
ARC. 1984. Status of water pollution control in the Atlanta region. Atlanta
Regional Commission, Atlanta, GA.
ARC. 1998. Water resources of the Atlanta region. Atlanta Regional Commis-
sion, Atlanta, Georgia, January, .
Cherry, R.N., R.E. Faye, J.K. Stamer, and R.L. Kleckner. 1980. Summary of
the river-quality assessment of the Upper Chattahoochee River basin,
Georgia. U.S. Geological Survey, Reston, VA.
EPD. 1981. Statement for the public hearing of the investigation and
oversight subcommittee of the Public Works and Transportation Com-
mittee of the U.S. House of Representatives, May 18, 1981. Environmen-
tal Protection Division, Georgia Department of Natural Resources, Atlanta,
GA.
Faye, R.E., W.P. Carey, J.K. Stamer, and R.L. Kleckner. 1980. Erosion,
sediment discharge, and channel morphology in the Upper
Chattahoochee River basin, Georgia. U.S. Government Printing Office,
Washington, DC.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to
1990. U.S. Bureau of the Census, Population Division, Washington, DC.
.
GADNR. 1991. Rules and regulations for water quality control. Georgia
Department of Natural Resources, Georgia Environmental Protection
Division, Atlanta, GA.
Hammer, Siler, George Associates. 1975. Regional assessment study of the
Chattahoochee-Flint-Apalachicola Basin. National Commission on Water
Quality, Washington, DC. NTIS No. PB-252-318.
Iseri, K.T., and W.B. Langbein. 1974. Large rivers of the United States. U.S.
10-14
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Chapter 10: Upper Chattahoochee River Case Study
Department of Interior, U.S. Geological Survey Circular No. 686, Washing-
ton, DC.
Karr, J.R. 1981. Assessment of biotic integrity using fish communities. Fisheries
6(6): 21-27.
Karr, J.R., K.D. Fausch, PL. Angermeier, P.R. Yant, and I.J. Schlosser. 1986.
Assessing biological integrity in running waters: A method and its
rationale. Special Publication 5. Illinois Natural History Survey, Champaign,
IL.
Kundell, J.E., and T. DeMeo. 1999. Cooperative regional water management
alternatives for metropolitan Atlanta: A report of the Regional Water
and Sewer Study Commission. Prepared for the Atlanta Regional Commis-
sion, Atlanta, Georgia, by the University of Georgia, The Carl Vinson Insti-
tute of Government.
Lawler, Matusky, and Skelly Engineers. 1989. Technical assistance for the
development of a defensible water quality model of the Chattahoochee
River. Georgia Department of Natural Resources, Environmental Protection
Division, Atlanta, GA.
Lium, B.W., J.K. Stamer, T.A. Ehlke, R.E. Faye, and R.N. Cherry. 1979.
Biological and microbiological assessment of the Upper Chattahoochee
River basin, Georgia. U.S. Geological Survey, Reston, VA.
Mauldin, A.C., and J.C. McCollum. 1992. Status of the Chattahoochee River
fish population downstream of Atlanta, Georgia. Georgia Department of
Natural Resources, Game and Fish Division, Atlanta, GA.
OMB. 1999. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
Richards, T. 1999. R.M. Clayton wastewater treatment plant, Atlanta, GA,
Personal communication. November 24, 1999.
Shelton, W.L., and W.D. Davies. 1975. Preimpoundment survey of fishes in the
West Point Reservoir Area (Chattahoochee River, Alabama and Georgia).
Georgia Academy of Science 33: 221-230.
Stamer, J.K., R.N. Cherry, R.E. Faye, and R.L. Kleckner. 1979. Magnitudes,
nature and effects of point and nonpoint discharges in the
Chattahoochee River basin, Atlanta to West Point Dam, Georgia. U.S.
Government Printing Office, Washington, DC.
USDOC. 1998. Census of population and housing. U.S. Department of
Commerce, Economics and Statistics Administration, Bureau of the Census -
Population Division, Washington, DC.
USEPA. 1971. Inventory of municipal waste facilities, Region IV: Alabama,
Florida, Georgia, Kentucky, Mississippi, North Carolina, South Caro-
lina and Tennessee. U.S. Environmental Protection Agency, Washington,
DC.
USEPA. 1980. National accomplishments in pollution control: 1970-1980,
some case histories. U.S. Environmental Protection Agency, Office of
Planning and Management, Program Evaluation Division, Washington, DC.
USEPA (STORET). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
watersheds, Washington, DC.
10-15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
USGS. 1999. Streamflow data downloaded from U.S. Geological Survey, United
States National Water Information System (NWTS)-W. Data retrieval for
historical streamflow daily values, .
USPHS. 1963. Inventory of municipal waste facilities, Region IV: Alabama,
Florida, Georgia, Kentucky, Mississippi, South Carolina, and Tennes-
see. U.S. Public Health Service, Washington, DC.
Woodward, R.L. 1949. Flow requirements for pollution abatement below
Atlanta, Georgia. U.S. Public Health Service, Environmental Health Center,
Cincinnati, OH.
10-16
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Chapter 11
Ohio River
Case Study
The Ohio River Basin, covering a
drainage area of 204,000 square miles,
extends 1,306 miles from the headwaters of
the Alleghany River in Potter County,
Pennsylvania, to the confluence of the Ohio
River with the Mississippi River at Cairo,
Illinois. With a length of 981 miles from the
confluence of the Alleghany and Monangahela
rivers with the Ohio River at Pittsburgh, Pennsyl-
vania, to Cairo, Illinois, and a drainage area of
192,200 square miles, the Ohio River is the largest single
tributary to the Mississippi River. In the United States, the Ohio
River ranks 10th in length and 3rd in mean annual discharge (258,000
cfs) (Iseri and Langbein, 1974).
Figure 11-1 highlights the location of the Ohio River case study
watersheds (catalog units) identified along the Ohio River as major
urban-industrial areas (e.g., Cincinnati, Ohio, and Louisville, Kentucky)
affected by severe water pollution problems during the 1950s and 1960s
(see Table 4-2). In this chapter, information is presented to characterize
long-term trends in population, municipal wastewater infrastructure and
effluent loading of pollutants, ambient water quality, environmental resources, and
uses of the Ohio River. Data sources include USEPA's national water quality
database (STORET), published technical literature, and unpublished technical
reports ("grey" literature) obtained from the Ohio River Valley Sanitation Com-
mission (ORSANCO) and other local agency sources.
The ORSANCO district encompasses three-quarters of the basin, account-
ing for 155,000 square miles of the Ohio River watershed. The district contains
nearly one-tenth of the Nation's population in one-twentieth of the Nation's
continental area. Ten percent of the people in the watershed receive their water
supply from the Ohio River. Population densities in the ORSANCO district range
from less than 50 people per square mile in the southwest to more than 600 in the
Figure 11-1
Hydrologic Region 5 and
the Ohio River Basin.
11-1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
eastern urban centers. Land use in the area is primarily agricultural, but concen-
trations of industry, coal mining, and oil and gas drilling are present throughout the
region. In addition to agricultural and industrial uses, the Ohio River supports fish
and wildlife habitats, water-based recreation, navigation, and power generation.
Utility of the Ohio River had significantly declined by the 1930s as the result
of rising discharges of raw sewage and untreated industrial waste. Widespread
public concern was spurred by drought-induced epidemics in 1930 and continually
high levels of bacterial pollution. Citizens of the Ohio River Valley proposed a
regional approach to water quality management in the form of an interstate
compact. Eight states joined the Ohio River Valley Sanitation Commission in 1948,
setting a precedent for cooperation among state, local, and private interests and
the federal government for unifying waste management within individual water-
sheds. The benefits of pollution control standards implemented through this
region-wide compact have been significant to the overall condition of waterways
in the Ohio River Basin.
Physical Setting and Hydrology
Nineteen major tributaries discharge to the Ohio River (Figure 11-2). The
155,000-square-mile ORSANCO district originates on the western slopes of the
Appalachian Mountains, with the Allegheny River flowing into the Ohio River
from the northwest and the Monangahela River from the south. The southwestern
portion of the district is characterized by rolling hills and wide valleys, and the
northwest is level or gently rolling. The elevation of the Ohio's riverbed drops 429
feet from the headwaters to the mouth at the confluence with the Mississippi
87
Figure 11-2
Location of Upper, Middle,
and Lower Ohio River
watersheds. River miles
shown are distances from
confluence of Ohio River
with Mississippi River at
Cairo, Illinois.
81°
11-2
-------
Chapter 11: Ohio River Case Study
River, with flow in the drainage basin generally toward the southwest. The
ORSANCO district is approximately 700 miles long and has an average width of
220 miles. Rainfall in the basin averages 45 inches, and the average annual
discharge of the Ohio River into the Mississippi River is 260,000 cfs. Variations in
rainfall, temperature, vegetation coverage, and snow storage have historically
caused wide ranges of runoff and streamflows. Low-flow conditions usually
occur in July through November; the monthly average, taken at Louisville, Ken-
tucky, ranges from 33,853 cfs in September to 239,613 cfs in March. Figures 11-3
and 11-4 show summer average flows (July-September) and monthly average
flows over the 55-year period from 1940 to 1995.
Canalization of the entire Ohio River and some of its tributaries was
achieved by 1929, converting the river into a series of backwater pools. The
original system of submergible wicket dams has been almost completely replaced
by high-lift permanent dams (Tennant, 1998).
300
£ „ 200:
^Si w
§
1
CO
looiT'r:
?9'4d i&d I'jjdd VgVd I'dsd"
6.5
6.0
5.5
5.0
4.5.o
4.0 £
3.5 |
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2.5 «
2.0 55
1.5
1.0
0.5
0.0
Figure 11-3
Long-term trends in mean,
10th, and 90th percentile
statistics computed for
summer (July-September)
streamflow in the Ohio
River. (USGSGage
03294500 at Louisville,
Kentucky.)
Source: USGS, 1999.
--• 90%ile
mean & ratio
500
S c •
H
$ f 200!
55 ;
Figure 11-4
Monthly trends in
streamflow for the Ohio
River. Monthly mean, 10th,
and 90th percentiles
computed for 1951-1980.
(USGS Gage 03294500 at
Louisville, Kentucky.)
Source: USGS, 1999.
ONDJFMAMJJAS
11 -3
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Population, Water, and Land Use Trends
The Ohio River Basin continues to be one of the most important agricultural
and industrial centers of the Nation. Population in the ORSANCO district has
increased steadily over the past few decades, and use of the water resources has
increased with the development of the basin. More than 3,700 municipalities, more
than 1,800 industries, and three major cities—Louisville, Cincinnati, and Pitts-
burgh—depend on the Ohio River Valley. The Ohio River case study area
includes a number of counties identified by the Office of Management and
Budget (OMB) as Metropolitan Statistical Areas (MSAs) or Primary Metropoli-
tan Statistical Areas (PMSAs). Table 11-1 lists the MSAs and counties included
in this case study. Figure 11-5 presents long-term population trends (1940-1996)
for the counties listed in Table 11-1. From 1940 to 1996, the population in the Ohio
Table 11-1. Metropolitan Statistical Area (MSA) counties in the Ohio River Basin case study. Source: OMB, 1999.
Wheeling, WV-OH MSA
Belmont County, OH
Marshall County, WV
Ohio, WV
Steubenville-Weirton, OH-WV MSA
Jefferson County, OH
Brooke County, WV
Huntington-Asland, WV-KY-OH
MSA
Boyd County, KY
Carter County, KY
Greenup County, KY
Lawrence County, OH
Cabell County, WV
Hancock County, WV
Wayne County, WV
Cincinnati-Hamilton, OH-KY-IN
CMSA
Dearborn County, IN
Ohio County, IN
Boone County, KY
Campbell County, KY
Kenton County, KY
Pendleton County, KY
Brown County, OH
Clermont County, OH
Hamilton County, OH
Warren County, OH
Butler County, OH
Louisville, KY-IN MSA
Clark County, IN
Floyd County, IN
Harrison County, IN
Scott County, IN
Bullitt County, KY
Jefferson County, KY
Oldham County, KY
Evansville-Henderson, IN-KY MSA
Posey County, IN
Vanderburgh County, IN
Warrick County, IN
Henderson County, KY
Figure 11-5
Long-term trends in
population in the Ohio
River Basin.
Sources: Forstall, 1995;
USDOC, 1998
1940 1950 1960 1970 1980 1990 1996
11 -4
-------
Chapter 11: Ohio River Case Study
River case study area increased by more than 50 percent (Forstall, 1995;
USDOC, 1998). Agriculture continues to be the dominant land use in the area
although extensive mining is conducted in the watershed; 70 to 80 percent of
the national total amount of bituminous coal and a significant amount of natural
gas and oil are present in the basin.
The Ohio River supports navigation, power generation, industrial cooling and
processing, warm-water aquatic habitats, public water supplies, and recreation.
Because the river serves as a water source to industries, agricultural lands, and
more than 3.5 million people, and as a waste receptacle for far larger numbers,
the river's environment has been placed in a fragile balance.
Historical Water Quality Issues
Growing concern for the deteriorating environmental conditions in the Ohio
River peaked in the early 1930s when serious drought turned many slackwater
pools into virtual cesspools and a series of epidemics plagued cities along the Ohio
River. Costs of water treatment increased dramatically from 1921 to 1934 as a
result of an estimated 80-fold increase in the bacteria levels present in the river.
In 1936 Congressman Brent Spence testified at a congressional hearing on the
pollution of navigable waters that "the Ohio River is a cesspool." At the same
hearing the State Health Commissioner of Kentucky added that "the Ohio River,
from Pittsburgh to Cairo, is an open sewer." In 1939 the city of Marietta, Ohio,
was forced to change its water supply source from the Ohio River to wells and
the Muskingum River as pollution levels in the river became untreatable. In 1951
only 39 percent of the sewered population was served by community treatment
facilities. Sections of the Ohio River still suffered oxygen depletion so severe that
aquatic life could not survive and pollution, bacteria levels, taste, and odor made
large sections of the Ohio River unsuitable for most uses.
Legislative and Regulatory History
Large-scale action was delayed by the need for cooperation throughout the
basin to achieve significant improvements in water quality. In 1908 the Ohio state
legislature adopted the Bense Act which, exempted every Ohio village and
municipality from installing sewage treatment works until similar facilities were
provided by all municipalities upstream from it. This attitude endured until 1924
when the Ohio River Valley Negotiating Committee reported an agreement
between industries and state health commissioners to cooperate in carrying out a
policy for the conservation of interstate streams. Congress authorized the states
to negotiate the compact in 1936 and approved the resulting document in 1940. In
June of 1948 the Federal Water Pollution Control Act (Public Law 80-845) was
passed and the ORSANCO Compact was signed by Illinois, Indiana, Kentucky,
New York, Ohio, Pennsylvania, Virginia, and West Virginia, setting a precedent
for cooperation among federal agencies, state governments, municipalities, and
industries. Soon after, wastewater treatment standards were enacted for the
Cincinnati pool. Bacterial quality objectives for the Ohio River were established in
1951, and an assessment of potential health hazards from trace constituents in
wastewaters was initiated. By 1954 municipal wastewater treatment standards
11-5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
for the Ohio River had been established. In relation to the industrial dischargers, a
resolution adopted in 1959 placed responsibility on industries for reporting spills
and accidental discharges to state agencies.
Following the 1965 Federal Water Quality Act, ORSANCO adopted stream
water quality recommendations. In 1970 ORSANCO Pollution Control Standard
1-70 revised the pollution control standards established in 1954, making secondary
treatment the minimum requirement for wastewater treatment plants and estab-
lishing equivalent treatment requirements for industry. From 1957 to 1965,
$82,786,500 in federal aid was allocated to 638 projects in the Ohio Valley. The
communities matched every federal dollar with $2.50 of local funds for a total of
$282,966,000 spent on improving conditions. The majority of treatment works,
both in place and under construction during this time, were equipped for second-
ary treatment. For 3 years before federal aid was offered, Pennsylvania provided
incentives for smaller communities to upgrade their treatment by offering funds to
communities upon compliance with standards. Although the population served by
municipal facilities has increased greatly under these programs (Figure 11-6),
increasingly high water quality criteria and limited funds have caused a sharp
increase in population served by facilities classified as inadequate between 19.65
and 1990.
Figure 11-6
Long-term trends in
population served by
municipal wastewater
treatment plants in the
ORSANCO District.
Sources: ORSANCO,
1978, 1988.
8-
1950
1960
1970
1980
1990
Raw
| | Pri+AdvPri $%% Sec
Advanced
11-6
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Chapter 11: Ohio River Case Study
Impact of Wastewater Treatment:
Pollutant Loading and Water
Quality Trends
Following the 1948 advances in cooperative management, water quality
conditions in the Ohio River began to improve. A dramatic decrease occurred in
the discharge of raw sewage from 1950 to 1963 (Figure 11-6). As a result of the
stringent permit requirements on dischargers and improvements in wastewater
treatment facilities implemented in the late 1960s and 1970s, even more advances
have been made to upgrade wastewater treatment plants. Levels of BOD5
effluent loading have decreased significantly, even as the influent loading contin-
ues to increase as population increases (Figure 11 -7). Corresponding to the
decreasing levels of pollutant loading is the increased amount of DO available to
support aquatic organisms. Figure 11-8 shows the typical oxygen sag curve
3000
LU
1950
1960
1970
1980
1990
Flow
I Effluent BODS
Figure 11-7
Long-term trends of
wastewater flow, influent
and effluent BOD5 for the
ORSANCO District. Data
based on population
served with 165 gallons
per person per day, influent
BOD6 of 215 mg/L, and
removal efficiencies of 36
percent (primary), 85
percent (secondary), and
95 percent (tertiary).
Sources: ORSANCO, 1978,
1987.
Cincinna OH (River Mile 46 )-470)
0
450 460 470 480 490 500 510 520
•^— River Miles from Cairo IL
Figure 11-8
Spatial distribution of DO
along the Ohio River
downstream of Cincinnati:
Oct.-Nov. 1963.
Source: HydroScience,
1969.
11-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
observed during the mid-1960s downstream from Cincinnati, Ohio, and indicates
the sampling locations shown in Figures 11-9, 11-10, and 11-11. These data clearly
illustrate an overall increase in oxygen following the 1972 CWA requirement for
secondary treatment. A remarkable improvement in oxygen concentration occurs
in the critical minimum occurring near North Bend/Fort Miami (milepoint 490) and
at the pool formed by Markland Lock/Dam (milepoint 449-453). During the 1988
drought, for example, levels of DO continued to meet standards near Cincinnati
and Louisville in contrast to the mid-1960s when consistent low-flow conditions
resulted in DO concentrations below water quality standards (see Figures 11-9
and 11-13). Using the data compiled for trends in DO near Cincinnati (Figure 11-
9) and Louisville (Figure 11-12), the mean summer 10th percentile level of DO
significantly improved after the CWA (1986-1995) in comparison to conditions
before the CWA (1961-1970) (Figure 11-13).
Water quality data collected since the 1950s indicate increased compliance
with federal and ORSANCO criteria for DO, BOD5, turbidity, pH, and many
other water quality factors (Cleary, 1978; Wolman, 1971). ORSANCO (1979)
Figure 11-9
Long-term trends of DO
near Cincinnati, Ohio
(miles 460-470) (RF1-
05090203002).
Source: USEPA (STORET).
10
8-
6-
4-
2-
?940 1950 1960 1970 1980
Cincinnati OH [River Mile 460-470]
1990
Mean Min Max
Figure 11-10
Long-term trends of DO at
North Bend/Ft. Miami, Ohio
(RF1-05090203012) (mile
490).
Source: USEPA (STORET).
1990
N.Bend/Ft.Miami OH [River Mile 490]
-A- Mean
Min
11-8
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Chapter 11: Ohio River Case Study
10!
| 8+-
§ 6- -
1
a 2-
)
Markland Pool [River Mile 449-453]
-A- Mean
Min
1990
Figure 11-11
Long-term trends of DO at
Markland Lock & Dam,
Kentucky (miles 449-453)
(RF1-05140101010).
Source: USEPA (STORET).
1940
1950
1960 1970
Louisville KY [River Mile 364-388]
1990
Figure 11-12
Long-term trends of DO at
Louisville, Kentucky (miles
364-388) (RF1-0514010
1001).
Source: USEPA (STORET).
Mean Mm Max
Louisville [RF1 05140101001]
Cincinnati [RF1 05090203002]
Figure 11-13
Before and after
comparison of summer
mean 10th percentile DO
near Louisville, Kentucky
(miles 364-368) and
Cincinnati, Ohio (miles
460-470) during 1961-70
and 1986-95.
Source: USEPA (STORET).
1961-70
1986-95
Louisville | j Cincinnati
11 -9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 11-14
Long-term trends in fish
diversity in the Ohio River.
Source: ORSANCO, 1982.
2.00-
.1
Q
65' ' ' ' 19
• • . —
n
o
. D .
5
70' ' ' '1C
k
J
(75 ' ' ' '19
• • —
•- ^
80' ' ' '19
85
Lower River A Middle River n Upper River
reports greater than 98.8 percent compliance for 15 out of 20 examined stream
quality criteria. In 1990 ORSANCO published a statistical analysis of data
resulting from water quality monitoring conducted over an 11-year period. De-
creasing trends at individual sampling points were reported for a majority of the
contaminants examined, and overall improving trends are indicated for total
phosphorus, ammonia, nitrogen, copper, lead, and zinc. An indication of the
improving water quality in the Ohio River is the marked increase in diversity of
fish species with the greatest improvement seen in the upper reaches of the river
(Figure 11-14). Increases are primarily noted in sport and commercially valuable
species, which tend to be more pollution-sensitive than other fish species.
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
There is little long-term information on biological trends in the Ohio River
(Pearson, 1992). Information on plants, invertebrates, and plankton is scarce or
nonexistent. The only historical population data are for mussels, which were
diverse and abundant in the 1800s but are less so now, even with water quality
improvements in the river.
Data on fish populations in the middle section of the Ohio River have been
collected since the 1950s and indicate that the populations have responded more
positively than mussels to improved water quality (Figure 11-15). The first com-
prehensive fish population study on the Ohio River was done by ORSANCO in
1957, and the study has continued almost yearly since then. The study reports fish
data according to section of the river—upper, middle, and lower. Louisville and
Cincinnati are located in the middle section of the river. Changes in fish diversity
since the study began have been most dramatic in the upper river, where a 40
11 -10
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Chapter 11: Ohio River Case Study
1957-60
1967-70
1974-80
1981-85
I Cincinnati Bl Louisville
Figure 11-15
Long-term trends in Ohio
River fish abundance at
Cincinnati and Louisville.
Source: Pearson, 1992.
percent increase has been measured, but diversity has increased by 13 percent in
the middle section as well (ORSANCO, 1982). Numbers of species and overall
fish biomass are still increasing in the middle section of the river though they have
not returned to their original levels. ORSANCO attributes the improvements to
increased DO concentrations and pH, and to decreased levels of toxic materials
in the river (ORSANCO, 1982).
Other studies also indicate continuing improvements in the quality of the
Ohio River habitat. Studies by Geo-Marine conducted in the early 1980s near
North Bend, Ohio (about 30 miles downstream of Cincinnati) found increasing
numbers of species of larval fish, a life stage generally sensitive to DO levels
(Geo-Marine, 1986). A trend toward a more even distribution of the numbers of
individuals among the species captured was found as well, indicating improved
habitat quality. The Ohio EPA has also conducted fish studies along the river.
Their studies have found an Index of Biotic Integrity (IBI) near North Bend
between 46 and 48 (OEPA, 1992). This is a fair to good rating, indicating habitats
where tolerant and intolerant benthic species are both found. Benthos are particu-
larly good indicators of long-term trends in water quality because the species are
generally sedentary and have long life spans. For pollution studies, benthos are
divided into three categories, and intolerant species are indicative of good water
quality because of their inability to survive in, or intolerance of, low DO concen-
trations. Ohio EPA's sampling at North Bend in 1991 found a total of 23 species,
with one intolerant species among them (Sanders, 1992a, 1992b; Plafkin et al.,
1989).
Water quality improvements in the Ohio River have benefited both commer-
cial and sport fisheries (Figure 11-15). Sportfishing, important recreationally and
for tourism, began returning to the river in the mid-1980s. In 1982 the Bass
Anglers Sportsman's Society held the Bass Champs Invitational at Cincinnati
because of the reported bass catch in the river (ORSANCO, 1981). Such con-
tests are now commonly held along the river.
11-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Summary and Conclusions
Significant improvements have been accomplished throughout the Ohio
River Basin through the combined efforts of federal, state, and local governments.
The last half century has seen a reversal of the previous trend of river degrada-
tion. As of the mid-1990s nearly 94 percent of the Ohio River Basin's sewered
population was served by at least secondary treatment. This accomplishment, on
such a large scale, has shown what regional cooperation can achieve. The Ohio
River now supports many uses that had previously been seriously impaired.
Support of use for public water supply and aquatic habitat is maintained along the
entire river. Sportfishing has returned, and the dramatic improvement in water
quality is reflected in the increasing number of fishing tournaments along the river,
including the 1983 Bass Masters Classic at Cincinnati.
Much progress has been made, but there is a recognizable need for further
action. Water-based recreation continues to be impaired by high bacteria levels in
the river. As of 1988 contact recreation was not supported on 59 percent of the
river and was fully supported on only 6.5 percent of the river. Fish consumption
advisories were still in effect for Kentucky, Ohio, Pennsylvania, and West Virginia
in 1989 due to high levels of PCBs and chlordane found in fish tissues
(ORSANCO 1989a). Certain metals, organic compounds, cyanide, phenol, copper,
zinc, oxygen, and temperature also continue to pose a problem. ORSANCO is
considering to address these and other stream quality impairments by addressing
nonpoint source pollution controls (Norman, 1991), combined sewer overflow
controls (Tennant et al., 1990), control of toxic chemicals (Vicory and Tennant,
1994), and control of ecological effects of hydropower development. Continued
improvements are seen in monitoring, detection, and regulation, as well as treat-
ment and spill response (Vicory and Tennant, 1993). The combination of present
efforts with past achievements has put the Ohio River Basin on the road to
recovery.
References
Cleary, E.J. 1978. Perspective on river quality diagnosis. J. WPCF 50(5): 825-
832.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to
1990. U.S. Bureau of the Census, Population Division, Washington, DC.
http://< www.census.gov/population/www/censusdata/cencounts.html>.
Geo-Marine. 1986. 1985 Ohio River Ecological Research Program. Adult
and Juvenile Fish and Ichthyoplankton Studies. December. Prepared for
Ohio Edison Company, Ohio Valley Electric Corporation.
HydroScience. 1969. Water quality analysis for the Markland Pool of the
Ohio River. Technical report prepared for Malcolm Pirnie Engineers,
Westwood, NJ.
Iseri, K.T., and W.B. Langbein. 1974. Large rivers of the United States.
Circular No. 686. U.S. Department of the Interior, U.S. Geological Survey,
Washington, DC.
Norman, C.G. 1991. Urban runoff effects on Ohio River water quality. Water
Environ. Tech. 3(6): 44-46.
11-12
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Chapter 11: Ohio River Case Study
OEPA. 1992. Ohio Environmental Protection Agency Water Quality Plan-
ning and Assessment Fish Information System (FINS): Fish survey data.
Ohio Environmental Protection Agency.
OMB. 1999. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
ORSANCO. 1978. ORSANCO in review. Ohio River Valley Sanitation Com-
mission, Cincinnati, OH.
ORSANCO. 1979. ORSANCO in review. Ohio River Valley Sanitation Com-
mission, Cincinnati, OH.
ORSANCO. 1981. Annual report. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
ORSANCO. 1982. Annual report. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
ORSANCO. 1985. Annual report. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
ORSANCO. 1986. Annual report. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
ORSANCO. 1987. 7957 status of wastewater facilities. Ohio River Valley
Sanitation Commission, Cincinnati, OH.
ORSANCO. 1988. ORSANCO: Forty years of service. Ohio River Valley
Sanitation Commission, Cincinnati, OH.
ORSANCO. 1989a. Water quality of the Ohio River, Biennial assessment:
1988-1989. Ohio River Valley Sanitation Commission, Cincinnati, OH.
ORSANCO. 1989b. Annual report. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
ORSANCO. 1990. Water quality trends, Ohio River and its tributaries.
Statistical analyses of data resulting from water quality monitoring
conducted by ORSANCO. Ohio River Valley Sanitation Commission,
Cincinnati, OH.
Pearson, W.D. 1992. Historical changes in water quality and fishes of the Ohio
River. In Water quality in North American river systems, ed. C.D. Becker
and D.A. Neitzel, pp. 207-231. Batelle Press, Columbus, OH.
Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M. Hughes. 1989.
Rapid bioassessment protocols for use in streams and rivers. Benthic
macroinvertebrates and fish. Results of pilot studies in Ohio and Or-
egon. EPA 444/4-89/001. U.S. Environmental Protection Agency, Office of
Water, Assessment and Watershed Protection Division. Washington, DC.
Sanders, R.E. 1992a. Day versus night electrofishing catches from near-shore
waters of the Ohio and Muskingum Rivers. Ohio J. of Science 92(3): 51-59.
Sanders, R.E. 1992b. Ohio's near-shore fishes of the Ohio River: 1991-
2000. (Year One: 1991 results). Prepared for the Ohio Department of
Natural Resources, Division of Wildlife, Ohio Nongame & Endangered
Wildlife Program. Columbus, OH.
Tennant, Peter. 1998. Ohio River Valley Sanitation Commission. Personal
communication, August 21,1998.
Tennant, P., C. Norman, and P. McConocha. 1990. Toxic-substance control for
the Ohio River. Water Environ. Tech. 2(10): 59-63.
11 -13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
USDOC. 1998. Census of population and housing. Prepared by U.S. Depart-
ment of Commerce, Economics and Statistics Administration, Bureau of the
Census - Population Division, Washington, DC.
USEPA (STORET). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
watersheds, Washington, DC.
USGS. 1999. Streamflow data downloaded from the U.S. Geological Survey's
National Water Information System (NWIS)-W. Data retrieval for historical
Streamflow daily values, .
Vicory, A.H., Jr., and P.A. Tennant. 1993. The Ohio River Valley Water Sanita-
tion Commission and its activities. Ohio J. of Science 93(2): 11.
Vicory, A.H., Jr., and P.A. Tennant. 1994. A strategy for monitoring the impacts
of combined sewer overflows on the Ohio River. Water Quality Interna-
tional '94. Part 1: Combined Sewer Overflows and Urban Storm Drain-
age. Biennial Conference of the International Association on Water Quality,
July 24-30,1994, Budapest, Hungary.
Wolman, M.G. 1971. The Nation's rivers. Science (174): 905-915.
11 -14
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Chapter 12
Upper
Mississippi
River Case
Study
The upper and lower watersheds of the Mississippi
River extend 2,340 miles from the headwaters in Lake Itasca,
Minnesota, to the Gulf of Mexico. With a drainage basin of 1.15
million square miles, the Mississippi River, known as the "Father of
Waters," drains 40 percent of the continental United States and
discharges an annual average flow of 640,000 cfs into the Gulf of
Mexico. On the basis of drainage area and mean annual discharge, the
Mississippi is the largest river in the United States (Iseri and Langbein,
1974) and is ranked by annual discharge as the sixth largest river in the
world (Berner and Berner, 1996). Figure 12-1 highlights the location of
the seven catalog units of Accounting Unit 070102 for the Upper
Mississippi River case study in the vicinity of Minneapolis-St. Paul in
Minnesota. The Twin Cities are one of the Nation's many major urban
areas characterized by water pollution problems during the 1950s and
1960s (FWPCA, 1966; USPHS, 1951; 1953). Federal enforcement
conferences were convened in 1964 and 1967 to investigate water
pollution problems in the Minnesota and Wisconsin sections of the
Upper Mississippi River (Zwick and Benstock, 1971).
In this chapter, data and information are presented to characterize
long-term trends in population, municipal wastewater infrastructure and effluent
loading of pollutants, ambient water quality conditions, environmental resources,
and uses of the Upper Mississippi River in the vicinity of the Twin Cities. Data
sources included STORET, EPA's national water quality database, USGS
streamflow records (USGS, 1999a), published literature, unpublished data, news-
letters, and technical reports obtained from the Metropolitan Council Environmen-
tal Services (MCES) in St. Paul and from other state, local, and federal agencies.
Data have also been obtained from a validated water quality model of the Upper
Mississippi River (Lung and Larson, 1995) to identify the progressive improve-
ments in dissolved oxygen and other water quality parameters attributed to
upgrades of the Metropolitan Wastewater Treatment Plant in St. Paul from
primary to secondary and advanced secondary with nitrification (Lung, 1998).
Figure 12-1
Hydrologic Region 7 and
the Upper Mississippi
River basin near
Minneapolis-St. Paul,
Minnesota.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
The Twin Cities of Minneapolis and St. Paul are the major urban centers for
more than 1,100 miles along the Mississippi River upstream of St. Louis, Missouri.
About one-third of the population and a majority of the commercial and industrial
activity of Minnesota are located within the Twin Cities metropolitan region.
Outside the Twin Cities, the Upper Mississippi watershed is primarily rural and
forested with the population dispersed in small towns and farms. The glaciated
topography of the watershed provides extensive habitat for fish and wildlife and
also supports an economy historically based on agriculture and wood products. In
addition to these economic sectors, industrial and manufacturing activities have
become significant components of the overall economy.
Physical Setting and Hydrology
The Upper Mississippi River basin (Hydrologic Region 7) covers a drainage
area of 171,500 square miles over a reach of 1,170 miles from the headwaters in
Lake Itasca to the confluence of the Missouri River with the Mississippi River at
Alton, Illinois, just upstream of St. Louis, Missouri (Iseri and Langbein, 1974)
(Figure 12-1). The water quality of the Upper Mississippi River has historically
been dominated by wastewater loading from the Twin Cities, as well as sedi-
ments, nutrients, pesticides, oxidizeable materials, and other pollutants from the
Minnesota River basin, the watershed of the Upper Mississippi River basin
(Catalog Unit 07010206) described in this case study includes a drainage area of
8,520 square miles extending 83 miles from the confluence of the Crow River
(UM milepoint 894) in Morrison County upstream of Anoka, Minnesota (Upper
Mississippi milepoint 871) to the confluence of the St. Croix River downstream of
Lock and Dam No. 2 at Prescott, Wisconsin (UM milepoint 811) (Figure 12-2).
96'
Figure 12-2
Location map of Upper
Mississippi River
(Accounting Unit 070102)
near Minneapolis-St. Paul,
Minnesota. River miles
shown are distances from
confluence of Mississippi
River with Ohio River at
Cairo, Illinois.
45
12-2
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Chapter 12: Upper Mississippi River Case Study
Characterized by rolling hills and plains with numerous lakes, the basin
topography reflects the effects of successive glacial advances over the region.
Upstream of the Twin Cities, the major tributaries to the Upper Mississippi are the
Minnesota River, the Rum River at Anoka, and the Crow River. Within the portion
of the watershed influenced by wastewater loading from the Twin Cities, five
locks and dams have been constructed for flood control, navigation, and hydro-
power purposes. Because of the flow-regulating nature of the series of locks and
dams, the river essentially flows as a series of controlled backwater pools with
relatively constant surface elevations. Over the 69-mile reach from Coon Rapids
Dam upstream of Minneapolis (UM river mile 866) to Lock and Dam No. 3 at
Red Wing, Minnesota (UM river mile 797), the river drops from an elevation of
830 feet to 661 feet above mean sea level (Hydroscience, 1979).
The series of locks and dams, supplemented by dredging, maintain a 9-foot-
deep navigation channel for commercial barge traffic. The navigation channel
was authorized by the U.S. Congress in 1928, and the locks and dams were
authorized in 1930. The U.S. Army Corps of Engineers is conducting a controver-
sial environmental study is assessing the impact of the lock and dam system on
the ecological integrity of the Upper Mississippi River. In addition to the ecological
effects of the flow control structures, the Great Flood of 1993 (Wahl et al., 1993)
has generated investigations of the role that artificial drainage and flood-control
structures might have played in actually increasing the extent of severe flooding in
some areas of the watershed.
On a seasonal basis, streamflow of the Upper Mississippi River reflects
peak precipitation during late spring snowmelt and early summer with severe
subfreezing winter conditions (Figure 12-3). Although the minimum flow occurs
during winter due to a reduction in watershed runoff as precipitation changes
from rain to snow and ice, the critical period for water quality problems is during
the low-flow, summer months. On the river itself, winter ice cover is intermittent,
varying considerably both spatially and temporally. Ponded areas of the Upper
Mississippi River, such as Lower Pool 2 and Lake Pepin (Pool 4), have perma-
nent ice cover for about 3 months during the winter; the more riverine reaches
freeze over only during extended periods of severe cold. DO levels are generally
Figure 12-3
Monthly mean, 10th, and
90th percentile streamflow
(1951-1980) at St. Paul,
Minnesota, USGS Gage
05331000.
Source: USGS, 1999a.
O N D J FMAMJJAS
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
high during winter because of very low water temperature and open water
conditions that allow oxygen exchange across the air-water interface. Reliable
streamflow records from a USGS gage 300 feet upstream of the Roberts Street
Bridge in St. Paul (UM milepoint 839.3) are available from 1892 to the present to
characterize long-term monthly, annual, and extreme flow statistics over a drain-
age area of 36,800 square miles (USGS, 1999a). Based on the historical data
recorded for water years 1892-1998, monthly flow ranges from a maximum of
26,060 cfs in April to a winter minimum of 4,544 cfs during February and a
summer low of 8,060 cfs during September. Over the period of record from 1892
to 1998, annual average discharge of the Upper Mississippi River at St. Paul has
• been 11,630 cfs, with the lowest daily mean flow of 632 cfs recorded on August
26, 1934, and the highest daily mean flow of 171,000 cfs observed on April 16,
1965 (USGS, 1999a). Using historical records from 1936-1979 to represent
streamflow variability after the series of locks and dams were constructed on the
Upper Mississippi River, the 7-day, 10-year flow (7Q10) for summer conditions
(June-September) at St. Paul is reported as 1,633 cfs (MPCA, 1981).
The long-term (1940-1995) interannual variation of mean, 10th, and 90th
percentile summer (July-September) streamflow is shown in Figure 12-4. The
historical record exhibits pronounced year-to-year variability of summer
streamflow. Based on data from 1951-1980, the long-term mean summer
(July-September) flow of 10,659 cfs is used to compute a normalized streamflow
ratio for each summer from 1940 to 1995 as dry (< 0.75), normal (0.75-1.50) or
wet(> 1.50). For example, the summers of 1962,1972,1978-79, 1983, 1985-86,
1991, and 1993-95 were all characterized by wet conditions, where the flow was
greater than 150 percent of the long-term summer mean. The summers of
1960-61,1964,1967,1870-71,1973-74,1976-77,1980, and 1987-89, in contrast,
were characterized by dry conditions, where the flow was less than 75 percent of
the long-term summer mean. The extreme droughts of 1976 (1,725 cfs, 16
percent of summer mean) and 1988 (2,334 cfs, 22 percent of summer mean) and
the Great Flood of 1993 (47,789 cfs, 450 percent of summer mean) are particu-
larly noticeable in the 55 years of historical records for the Upper Mississippi
River at St. Paul.
Figure 12-4
Long-term trends of
summer (July-
September) mean, 10th,
and 90th percentile
streamflow at St. Paul,
Minnesota, USGS Gage
05331000.
01 111 ni
1940 1950 1960 1970
1980
1990
0.0
2000
90%ile
mean & ratio
12-4
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Chapter 12: Upper Mississippi River Case Study
Population, Water, and Land Use Trends
Beginning in 1838 when the Twin Cities area was first opened for settle-
ment, the abundant land and water resources attracted homesteaders. The
confluence of the Minnesota River and the Upper Mississippi River served as an
important transportation link between military and trading posts and the growing
towns and cities along the Mississippi River. St. Anthony's Falls provided a natural
source of power for lumber and grist mills. The fertile soil supported an agricul-
tural economy, and the vast forests provided resources for a growing wood
products industry. Uses for the Upper Mississippi River have included municipal
and industrial water supply, commercial navigation, log transport, commercial
fishing, hydropower, and water-based recreational activities. Beginning with the
construction of an urban sewer system in 1871, the Upper Mississippi River has
also been used for wastewater disposal.
As a component of the Lake Pepin Phosphorus Study, conducted from 1994
to 1998, historical records of land uses, agricultural practices (e.g., manure
applications and commercial fertilizer uses), and wastewater discharges, compiled
beginning ca. 1860, were used to correlate long-term changes in land uses in the
watersheds of the Upper Mississippi River, the Minnesota River, and the St. Croix
River with long-term changes in sediment and phosphorus loading to Lake Pepin
(Mulla et al., 1999). As of the mid-1990s, the USGS (1999b) had classified about
60 percent of the watershed (Upper Mississippi River, Minnesota River, and St.
Croix River) as agriculture and 23 as forest. The remaining 17 percent of the
drainage basin was classified as urban and suburban (5 percent), water (5
percent), and wetlands (7 percent) (USGS, 1999b).
The Upper Mississippi River case study area includes a number of counties
identified by OMB (1999) as a Metropolitan Statistical Area (MSA) (Table 12-1).
Long-term trends in the population of the 13-county Minneapolis-St. Paul MSA
are shown in Figure 12-5. Resident population in this MSA increased by 150
percent from 1.1 million in 1940 to 2.76 million in 1996. After a small increase of
population from 1940 to 1950, the greatest rate of growth occurred during the
1950s and 1960s, when population increased by 23-27 percent. The rate of
population growth then declined during the 1970s to 8.5 percent, with an increase
to 15 percent during the 1980s. During the period from 1990 to 1996, population
increased by 9 percent (Forstall, 1995; USDOC, 1998). Reflecting population
growth in the Twin Cities area, the population served by the Metro plant increased
from 1.04 million in 1962 to 1.68 million in 1997. By 2020, the plant is expected to
provide service to 1.94 million people (Larson, 1999).
Table 12-1. Metropolitan Statistical Area (MSA) counties in the Upper Mississippi
River case study. Source: OMB, 1999.
Anoka Scott
Carver Sherburne
Chicago Washington
Dakota Wright
Hennepin Pierce
Isanti St. Croix
Ramsey
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 12-5
Long-term trends in
population for the
Minneapolis-St. Paul, MN-
Wl MSA counties for the
Upper Mississippi River
case study area.
Sources: Forstall, 1995;
USDOC, 1998.
1940 1950 1960 1970 1980 1990 1996
Historical Water Quality Issues
As with many other urban areas of the United States, the Upper Mississippi
River was grossly polluted early in the 20th century because of growing urban
populations and inadequately treated municipal and industrial wastewater dis-
charges. Municipal officials simply relied on the natural flushing of rivers to dilute
the human and industrial waste products of the growing metropolitan areas. City
sewers, first constructed in 1871 in the Twin Cities, collected storm water and
sewage and discharged them directly into the river. By the early 1900s, the Upper
Mississippi River was unable to biologically assimilate the untreated wastewater
collected from the Twin Cities (MWCC, 1988).
Before construction of a lock and dam in Minneapolis in 1917, annual peak
spring flows maintained a minimally acceptable degree of water quality by the
physical removal of raw sewage and other waste materials accumulated during
the previous year in the Twin Cities area. Construction of the lock and dam,
however, drastically altered this natural cycle by slowing the current of the river
and reducing the flushing effect of the peak spring flows. By 1920, 3 million cubic
yards of sewage sludge had accumulated in the pool created by the lock and dam.
Water quality was severely degraded by depletion of dissolved oxygen from
decomposition of the sludge bed. Bacteria levels were extremely high, sewage
sludge mats floated on the surface, and the river was noxious from hydrogen
sulfide gas caused by septic conditions during the warm summer months. The
Upper Mississippi River was grossly polluted for a distance of 30 miles from St.
Anthony's Falls in Minneapolis to the St. Croix River at Prescott, Wisconsin
(MWCC, 1988).
A 1928 joint report by the Minnesota and Wisconsin State Boards of Health
stated that "a zone of heavy pollution extends from Minneapolis to the mouth
of the St. Croix." The state report pronounced "the river in this zone . . . unfit
for use as a water supply . . . fish life has been exterminated. " The report
stated that the river was "a potential danger from a health standpoint. "
Beginning with a river survey in 1926, the State Board of Health documented DO
12-6
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Chapter 12: Upper Mississippi River Case Study
levels of less than 1 mg/L over a 25-mile reach from St. Paul to Hastings, Minne-
sota, that could not support a healthy aquatic ecosystem, including pollution-
tolerant carp (Mockavak, 1990). From 1926 to 1937, minimum DO levels of 1 to 2
mg/L indicated less than 10 percent of oxygen saturation over a 20- to 25-mile
reach downstream from St. Paul (Wolman, 1971). Bacteria levels were also
extremely high, with total coliform concentrations of 105 to 106 MPN/100 mL
measured downstream of St. Paul (MRI, 1976). The extent of the public health
risk incurred from the discharge of raw sewage by the Twin Cities was made
painfully clear in 1935 when a failure of the chlorination units at the public water
supply plant resulted in a serious typhoid epidemic with 213 cases and 7 deaths
(USPHS, 1953).
In adopting the 1928 Board of Health recommendations, the Twin Cities
became the first major city on the Mississippi River to implement primary treat-
ment and chlorination for its municipal water pollution control plant in 1938. Water
quality quickly improved dramatically as the floating mats of sludge disappeared,
and DO levels increased to better than 3 mg/L from 1942 through 1955
(Mockovak, 1990; Wolman, 1971). Within 2 years fish returned and anglers
reported catching walleye and other game fish in parts of the river that had been
devoid of game fish prior to 1938. Maurice Robbins, a former deputy administra-
tor of the Metropolitan Waste Control Commission (MWCC), recalled that "The
impact [of waste treatment] on the river was tremendous . . . no more dead
fish, no more sewage smell" (MWCC, 1988).
With increasing population (Figure 12-5), growth eventually overwhelmed
the capacity of the river to assimilate the wastewater discharge from the primary
Metro plant during the mid-1950s through the mid-1960s. Water quality once
again deteriorated to conditions reminiscent of the 1920s and 1930s. During the
summer of 1964, the Federal Water Pollution Control Administration (FWPCA)
conducted a water pollution survey of the Upper Mississippi River that docu-
mented severe degradation of water quality (FWPCA, 1966). In contrast to an
average of about 30,000 MPN/100 mL near St. Paul during the 1950s, total
coliform densities ranged from 460,000 to 17,000,000 MPN/100 mL 9 miles
downstream of St. Paul. Minimum DO levels of less than 1 mg/L were also
recorded for 15 miles downstream of St. Paul. The biological health of the river
abruptly changed, with a zone of degradation and decay extending 20 miles from
St. Paul to Lock and Dam No. 2 at Hastings, Minnesota. The river bottom, thick
with sewage sludge, was found to be devoid of the benthic organisms usually
associated with clean waters (FWPCA, 1966; WRE, 1975).
In 1966 the Metro plant was upgraded to secondary treatment using the
activated sludge process. Water quality once again improved, surpassing the 1928
guidelines. The rapidly growing suburban population, however, tended to generate
more residual waste load than could be removed by upgrading the plant to sec-
ondary treatment. Regardless of the Metro plant upgrades, annual high spring
flows caused flooding of the plant, resulting in the discharge of raw sewage into
the river. During the late 1960s, only 4 of the 33 suburban treatment plants
provided adequate levels of treatment, thus contributing to the overall pollution
loading of the river. Minneapolis and St. Paul further contributed to periodic
pollution loading to the river through a network of combined storm water and
sewage collection sewers that discharged raw sewage during rainstorms.
12-7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
In 1984 the Metro plant was upgraded once again to advanced secondary
treatment with nitrification, designed to reduce effluent levels of ammonia. After
implementation of secondary and advanced secondary waste treatment for the
wastewater treatment plants of the Twin Cities area by the mid-1980s, water
quality of the Upper Mississippi River routinely has been in compliance with
water quality standards for dissolved oxygen and un-ionized ammonia. In contrast
to the record of compliance for oxygen and un-ionized ammonia, turbidity levels
have exceeded water quality objectives as a result of nonpoint source runoff of
sediment from the Minnesota River basin (MWCC, 1994). Because the land uses
of the Minnesota River basin are dominated by agricultural row crops and the
fine-textured soils further contribute to sediment losses, the annual mean (1976-
1996) sediment yield of 134 Ib/acre-yr from the Minnesota River watershed is
almost five times greater than the annual mean sediment yield of 28 Ib/acre-yr
estimated for the Upper Mississippi River basin upstream of Lock & Dam No. 1
(Meyer and Schellhaass, 1999). Fecal coliform levels also remained high and
often violated state water quality standards through the mid-1980s because of
combined sewer overflows during rainstorms. Fecal coliform bacteria samples are
in compliance with Minnesota water quality standards if the monthly geometric
mean is less than 200 MPN/100 mL and any individual sample does not exceed
2000 MPN/100 mL.
In 1984 it was estimated that 4.6 billion gallons per year of raw sewage and
storm water were discharged to the Upper Mississippi River. In response to this
water quality problem and public pressure, the Twin Cities implemented an
aggressive $320 million (1996 dollars) construction program from 1985 to 1995
intended to accelerate the completion of the ongoing project to separate the
combined sewers (MCES, 1996). As a result of the separation of storm water
and raw sewage from the combined sewer system, fecal coliform bacteria levels
have declined considerably, and compliance with state water quality standards has
improved greatly at stations monitored at Lock and Dam No.l, St. Paul, Grey
Cloud Island, and Pool 2 (Buttleman and Moore, 1999). Figure 12-6 shows the
reduction in bacteria levels and the corresponding improvement in compliance
with water quality standards. The monitoring station at St. Paul exhibits the
greatest improvement, with compliance achieved at the 71 percent level for
samples collected from 1996 to 1998. High bacteria levels, however, do occasion-
ally occur in the heavily urbanized area upstream of Lock and Dam No. 1; the
high levels apparently are associated with urban storm water runoff (Buttleman
and Moore, 1999).
To remedy the periodic flooding of the Metro plant that resulted in the
discharge of raw sewage to the river, flood protection projects were completed in
1975 and effluent pumps were installed in 1977. The pumps allowed the Metro
plant to treat wastewater during the annual spring floods. The success of the
flood control efforts at the Metro plant was dramatically demonstrated during the
flood events of 1993 and 1997 when the plant recorded 100 percent compliance
with NPDES permit limits during these two extreme events. Many other water
pollution control plants in the region were forced to bypass waste treatment as a
result of these extraordinary floods (Larson, 1999). In addition to their use for
flood control, the effluent pumps are used during low-flow conditions when DO
levels are depressed to aerate the effluent to increase ambient oxygen levels in
the river.
12-8
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Chapter 12: Upper Mississippi River Case Study
100%
494
500
1976-85
1986-95
1996-98
| | % compliance ^ #/100 mL
Figure 12-6
Pre- and post-CSO
separation project trends
in fecal coliform bacteria
for the Upper Mississippi
River at St. Paul. State
standard for fecal coliform
bacteria is 200 MPN/100
ml based on monthly
geometric mean from May
to October.
Source: Buttleman and
Moore, 1999.
Responding to federal industrial pretreatment requirements promulgated in
1979, the Twin Cities initiated a program to reduce discharges of heavy metals to
the Upper Mississippi River. A comprehensive strategy was adopted in 1981 to
reduce the discharge of heavy metals from municipal water pollution control
plants contributed by sanitary sewer discharges from industrial sources. By 1992,
a decade after beginning the program, the loading of heavy metals to the river had
been reduced by an average of 82 percent, with declines in ambient levels of
heavy metals. Using sediment cores collected in Lake Pepin, Balogh et al. (1999)
have reconstructed historical loading rates of mercury from ca. 1800 to 1996 from
the Upper Mississippi River watershed to Lake Pepin (Figure 12-7). Averaging
the sediment core data by 10-year intervals, Balogh et al. estimated a loading rate
of 3 kg/yr to characterize naturally occurring deposition of mercury under pristine
conditions before European settlement began ca. 1830. Mercury deposition
progressively increased during the 19th and 20th centuries, with about one-half of
the total mercury load deposited from 1940 to 1970 and the peak accumulation
rate of 357 kg/yr identified during the 1960s. As a result of decreasing the
discharges of mercury from municipal and industrial wastewater plants, the
2000.
1980!
1960'
1940!
1920!
1900!
1880!
1860!
1840!
1820;
1800"
^_^^
S^^~
M
•
1
•
100
400
Figure 12-7
Historical mercury loading
rates in the Upper
Mississippi River
reconstructed from
sediments of Lake Pepin.
Sediment core data
averaged at 10-year
intervals from 1800-1810
through 1980-1989 and
1990-1996.
Source: Balogh et al.,
1999.
Mercury Accumulation (kg/yr)
12-9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
deposition rate in Lake Pepin has declined by almost 70 percent from the maxi-
mum loading during the 1960s to 110 kg/yr during 1990-1996. Although the
investment in water pollution control has been very successful in reducing mer-
cury in the Upper Mississippi River, ambient levels of mercury are still 30 times
greater than the pristine conditions of the early 1800s (MCES, 2000). As of the
late 1990s, the MCES is actively working to monitor and reduce even further the
remaining sources of heavy metals, including mercury discharges to the river by
wastewater treatment plants (MCES, 2000).
During the 1950s and 1960s, the depletion of dissolved oxygen in Pool 2 of
the Upper Mississippi River near St. Paul adversely affected pollution-intolerant
fish and other aquatic organisms. Studies during the early 1960s, for example,
documented that burrowing mayflies (Hexagenio), an aquatic organism that is
very sensitive to low DO conditions, were very scarce or absent from Pools 2 and
3 and Lake Pepin (Pool 4) of the river (Fremling, 1964). With the restoration of
healthy levels of dissolved oxygen beginning in the mid-1980s, an abundance of
mayflies once again colonized suitable habitats in the Upper Mississippi River
from St. Paul to Lake Pepin after a 30-year absence from the river (Fremling and
Johnson, 1990; MDNR, 1988). The resurgence of mayflies, significant improve-
ments in ambient levels of DO and fecal coliform bacteria in Pool 2, and the
reduction of mercury loading to the sediments of Lake Pepin demonstrate the
successes of the water pollution control efforts implemented beginning in the
1980s. The Metro plant was upgraded to advanced secondary treatment with
nitrification in 1984; the industrial pretreatment program was begun in 1982; and
the accelerated CSO separation project, initiated in 1985 to jump-start an ongoing
sewer separation project, was completed in 1995.
Legislative and Regulatory History
The Minnesota State Legislature passed an act in 1885 to prevent the
pollution of rivers and other water supply sources. For the next 60 years, the
Minnesota Board of Health had responsibility for water pollution problems. By
1907 the State Board of Health realized that consumption of drinking water
contaminated by raw sewage discharges posed a serious public health threat.
Without any authority, the Board of Health attempted to pressure the Twin Cities
communities to install wastewater treatment facilities. In 1917 the State Board of
Health adopted regulations requiring towns to submit plans for sewers and
wastewater treatment plants prior to construction. The Board also conducted
water pollution surveys and made various recommendations for controlling
pollution. Letters to the city councils of the Twin Cities urging action on controlling
the discharge of raw sewage went unanswered in 1923 and 1925. At the request
of the State Board of Health, the U.S. Public Health Service conducted the first
water pollution survey of the Upper Mississippi River from the Twin Cities to
Winona, Minnesota, in 1926.
During the 1920s the Izaak Walton League, the Engineers Society of St.
Paul, the Engineering Club of Minneapolis, and other private groups lobbied for
immediate action on the problem of raw waste disposal into the river. In 1926 the
Minneapolis Sanitary Commission was created to study "the condition of the
river and the problems of sewage disposal" (MWCC, 1988). In 1927, when
12-10
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Chapter 12: Upper Mississippi River Case Study
the Metropolitan Drainage Commission was formed, raw sewage was discharged
through 84 outfalls over a network of 1,125 miles of sewers (MWCC, 1988).
Maurice Robbins, a former deputy administrator of MWCC, remembering his
experiences sampling the river during those years, stated that "It could get pretty
awful down by the river. There were floating feces, dead fish and a terrible
sewer smell" (MWCC, 1988).
In 1927 the State Board of Health was given the authority and the responsi-
bility to administer and enforce all laws related to water pollution in Minnesota.
The legislature directed the State Board of Health to form a Metropolitan Drain-
age Commission. The legislature, however, did not provide any substantial basis
for managing waste disposal. In 1933, a decade after the Minnesota State Board
of Health had begun to document the pollution problems of the Upper Mississippi
River, the Minneapolis-St. Paul Sanitary District was finally created to oversee
construction of the first primary wastewater treatment plant in the Twin Cities
region. The primary treatment plant, located near Pig's Eye Lake in St. Paul, went
online in 1938.
In 1945 the legislature passed the Water Pollution Control Act to establish
the Water Pollution Control Commission for the regulation of the emerging
problems of water pollution. The Minnesota Act, amended in 1951, 1959, and
1963, was regarded as one of the better water pollution control acts in the United
States (FWPCA, 1966). The main mission of the new Water Pollution Control
Commission was to direct the construction of primary wastewater treatment
plants for the smaller municipalities in the Twin Cities metropolitan area.
In 1967 the state legislature formed the Metropolitan Council as a regional
coordination agency. In 1969 the Metropolitan Waste Control Commission
(MWCC) was given the regional responsibility for wastewater collection and
treatment systems for 33 plants within 200 political jurisdictions of the seven-
county Twin Cities area. In 1967 the legislature also created the Minnesota
Pollution Control Agency (MPCA) to replace the Water Pollution Control Com-
mission. The new agency was soon given authority to regulate and enforce
effluent limits for municipal and industrial treatment plants. The establishment of
the U.S. Environmental Protection Agency and the enactment of the 1972 Clean
Water Act further strengthened the regulatory powers for requiring uniform
effluent limits for wastewater dischargers. In July 1994 the MWCC and transit
services were merged with the Metropolitan Council. The responsibility for
operating municipal wastewater treatment plants was delegated to the Environ-
mental Services Division of the Metropolitan Council (MCES).
Following the 1972 Clean Water Act, the MWCC, with federal (75 percent)
and state (15 percent) funding assistance, spent more than $350 million to dra-
matically improve the technology of the Metro plant, upgrade other facilities, and
build interceptor sewer systems (MWCC, 1988). During the 1970s and 1980s,
MWCC phased out or upgraded old plants or constructed new plants for many of
the suburban communities in the Twin Cities region. MCES now operates the
Metro plant and eight other treatment plants in the Twin Cities area. The Metro
plant and three other wastewater treatment plants discharge to the Upper Missis-
sippi River; three plants discharge effluent to the Minnesota River; and the St.
Croix River and the Vermilion River each receive effluent discharges from one
municipal plant.
12-11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 12-8
Long-term trends in
population served and
effluent flow for the Metro
plant in St. Paul.
Source: Larson, 1999.
Impact of Wastewater Treatment:
Pollutant Loading and Water Quality
Trends
During the 1960s and 1970s, effluent loading from the Metro plant ac-
counted for more than three-quarters of the total point source load of BOD5 in the
section of the Upper Mississippi River from the Twin Cities to the St. Croix River.
Because this one wastewater treatment plant, the Metro plant, accounted more
than 75 percent of the total point source load, historical effluent data from the
Metro plant can serve as an indicator to demonstrate the success of public
investments to upgrade the plant in improving water quality in the Upper Missis-
sippi River. Figures 12-8 through 12-11 present time-series trend data for popula-
tion served, effluent flow, BOD,., total suspended solids (TSS), total Kjeldahl
nitrogen (TKN), and ammonia loading for the Metro plant (Larson, 1999).
During the early 1960s, the Metro plant served 1.05 million people and
discharged 158 mgd to the Upper Mississippi River. By 1997 the population
served by Metro had grown to 1.7 million with a corresponding increase in the
effluent discharge rate to 225 mgd (Figure 12-8). Since enactment of the Clean
Water Act in 1972, effluent BOD5 loading from the Metro plant has been reduced
greatly from the peak loading period of the mid-1960s. Before upgrading the
Metro plant, effluent BOD5 loading peaked at about 330,000 Ib/day in 1968. After
upgrading to secondary in 1966, effluent loading dropped to 114,000 Ib/day by
1970 and 77,000 Ib/day in 1973. Since the 1980s, effluent loading of BOD5 has
continued to decline as a result of additional upgrades (e.g., advanced secondary
in 1984) and replacement, or abandonment, of 21 of the 33 suburban wastewater
treatment plants that existed in 1969 when MWCC assumed responsibility for
plant operations. BOD5 loading from Metro declined again to 40,000 Ib/day by
1980 and to 27,000 Ib/day by 1990 (Figure 12-9). Over a 30-year period, upgrades
and improvements to the Metro plant have reduced effluent BOD5 loading by 95
percent from the historical peak loading of 330,000 Ib/day in 1968 to only 17,000
Ib/day in 1998. Over the same period, the effluent concentration of BOD5 has
been reduced from 184 mg/L in 1968 to 9.7 mg/L in 1998.
?960' ' 1965' ' 1970' ' 1975' ' ^80
Flow
-•• • Population Served
12-12
-------
Chapter 12: Upper Mississippi River Case Study
Upgrades and improvements to the Metro plant have also resulted in large
reductions in effluent loading of suspended solids and nitrogen. TSS loading has
dropped by 95 percent from the peak loading rate of 219,000 Ib/day in 1968 to
10,000 Ib/day by 1998; effluent concentration declined from 122 mg/L in 1968 to
5.7 mg/L by 1998 (Figure 12-10). Based on effluent data from monitoring that
began in 1971, TKN loading has dropped by 78 percent from the peak loading
rate of 36,500 Ib/day in 1982 to 7,800 Ib/day by 1998; effluent concentration has
been reduced from 21 mg/L in 1982 to 4.5 mg/L by 1998 (Figure 12-11). Prior to
the upgrade to advanced secondary with nitrification, toxicity-based water quality
standards for the un-ionized portion of ammonia were frequently violated in the
Upper Mississippi River. After upgrading the plant to nitrification with ammonia
removal in 1984, effluent discharges of ammonia declined considerably. Using
effluent data collected since 1975, ammonia nitrogen (NH3-N) loading has
dropped by 90 percent from the peak loading rate of 25,500 Ib/day in 1982 to
2,600 Ib/day by 1998. The effluent concentration of ammonia has been reduced
from 14.7 mg/L in 1982 to 1.5 mg/L by 1998 (Figure 12-11).
400:
~ 350:
£ '-
| 300;
8 250^
5" 200;
§ 150!
§ 1003
200
175
150'
125;
100]
75
50
:25
?960' ' 1&5 ' ' WO' ' 1975
' 1985 '
1995 ' ' 20o8
Figure 12-9
Long-term trends in
effluent loading of BOD5 for
the Metro plant in St. Paul.
Source: Larson, 1999.
BODS Load
BODS Concentration
125
UJ
Figure 12-10
Long-term trends in
effluent loading of TSS for
the Metro plant in St. Paul.
Source: Larson, 1999,
TSS Load
TSS Concentration
12-13
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 12-11
Long-term trends in
effluent loading of TKN and
ammonia-N for the Metro
plant in St. Paul.
Source: Larson, 1999.
1960 1965 1970 1975 1980 1985 1990 1995
• TKN Load -» • NH3 Load
TKN Cone. -* • NH3 Cone.
Beginning in the 1920s through the 1970s, the major water quality issues for
the Upper Mississippi River have been bacterial contamination and depletion of
DO from sewage discharges and combined sewer overflows. Historical DO data
sets collected since 1926 illustrate the dramatic change in long-term trends in the
spatial distribution of DO recorded 5 miles downstream of the confluence with the
Minnesota River near St. Paul (UM milepoint 840) to Lock and Dam No. 3 at
Red Wing, Minnesota (UM milepoint 797) (Figure 12-12). These historical data
sets clearly illustrate the adverse impacts of wastewater loading and the effec-
tiveness of upgrades in wastewater treatment implemented in 1938, 1966, and the
early 1970s at the Metro plant. Because of the hydraulic characteristics of the
Upper Mississippi River, minimum DO levels have been consistently observed in a
zone 5 to 15 miles downstream of the Metro plant discharge, within the oxygen
sag region from Newport (UM milepoint 820) to Grey Cloud (UM milepoint 830).
Using historical data available from EPA's STORE! water quality database,
the long-term trend of summer DO and BOD5 (1940-1995) has been compiled
from monitoring station records extracted for RF1 reach 07010206001 from the
Minnesota River (UM milepoint 844.7) to the St. Croix River (UM milepoint 811).
Figure 12-12
Spatial trends of August
DO in the Upper
Mississippi River from
1926 to 1988-96 from St.
Paul (UM milepoint 840) to
Lock & Dam No. 3 at
Redwing (UM milepoint
797).
Sources: Larson, 1999;
Mockovak, 1990; MWCC,
1989; Johnson and Aasen,
1989.
10
5-
1
0 ~l i i T~I i i i r i i i i i i i i i i I" i i i i i i i i i i r i i i i i i i i i i ri i i i i i i i i
-850 -840 -830 -820 -810 -800
Upper Mississippi River Mile
-790
12-14
-------
Chapter 12: Upper Mississippi River Case Study
Although DO is characterized by a high degree of interannual variability because
of temporal variability in streamflow and the spatial gradient over this 34-mile-long
reach, there has been a definite improvement in this long reach between the
1960s when summer mean oxygen levels ranged from approximately 4 to 7 mg/L
to the period from the mid-1970s through the mid-1990s when summer mean
oxygen levels consistently ranged from approximately 7 to 8 mg/L even during the
drought conditions of 1987-1988 (Figure 12-13). The trend of improvement in DO
during the 1980s and 1990s is consistent with the long-term trend of improvement
in ambient BOD5 extracted for the same reach (Figure 12-14). During the 1960s
and 1970s, summer mean BOD5 ranged from approximately 4 to 8 mg/L. During
the 1980s mean BOD5 ranged from approximately 2.5 to 4.5 mg/L. In the period
1990-1995, mean ambient BOD5 declined even further to levels ranging from
approximately 2 to 3.5 mg/L as a result of upgrading the Metro plant to advanced
secondary with nitrification in the late 1980s.
In interpreting the year-to-year variability of the long-term DO data from
1940 through 1995, it is important to understand the influence of streamflow on
summer oxygen levels under the peak effluent loading conditions of the 1960s and
Figure 12-13
Long-term trends of mean,
10th percentile, and 90th
percentile summer DO in
the Upper Mississippi
River for RF1 reach
07010206001 from the
Minnesota River (DM
milepoint 844.7) to the St.
Croix River (DM milepoint
811).
Source: USEPA (STORET).
1940 1950 1960 1970 1980 1990 2000
St. Croix R-Minnesota R [DM 811-844.7]
10
1940 1950 1960 1970 1980 1990
St. Croix R-Minnesota R [UM 811-844.7]
mean
90%ile
2000
Figure 12-14
Long-term trends of mean,
10th percentile, and 90th
percentile summer BOD5
in the Upper Mississippi
River for RF1 reach
07010206001 from the
Minnesota River (UM
milepoint 844.7) to the St.
Croix River (UM milepoint
811).
Source: USEPA (STORET).
12-15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
early 1970s compared to the greatly reduced effluent loading conditions that have
characterized the Twin Cities area since the mid-1970s. Under conditions of
similar effluent loading rates, DO decreases during low-flow conditions in contrast
to a relative increase during higher summer flow conditions. Over years of
comparable effluent BOD5 loading, the interannual cycles that appear to show
trends of either "improvement" or "degradation" in DO (Figure 12-13) are caused
primarily by year-to-year variability of summer streamflow (see Figure 12-4). An
accurate evaluation of the long-term trend in improvement of DO is possible only
by filtering the time series of oxygen records to extract only those summers that
are characterized by dry streamflow conditions.
Figure 12-15 shows long-term trends in DO conditions for "dry" summers
for a subreach of the RF1 reach 07010206001 for the critical oxygen sag location
from Newport (UM milepoint 820) to Grey Cloud (UM milepoint 830). The time
series record of DO data in Figure 12-15 is extracted to highlight the trend in
improvement for summers of comparable "dry" streamflow conditions when the
flow at the St. Paul USGS gage was less than 75 percent of the long-term (1951-
1980) summer mean. During the 1960s, low-flow summer mean DO levels
violated water quality standards with concentrations as low as less than 1 mg/L in
1961 to approximately 4 mg/L in 1964. After the upgrade of the Metro plant to
advanced secondary with nitrification in the late 1980s, mean summer DO levels
in the critical subreach had improved to levels as high as approximately 6 to 7 mg/
L even during the extreme drought conditions of 1987-1988. Using before and
after data in a postaudit model applied to the low-flow summers of 1976 and 1988,
Lung (1996a) has clearly demonstrated that the improvements in DO can be
directly related to upgrades of the Metro plant.
As shown by the historical records for fecal coliform bacteria (Figure 12-6),
DO (Figure 12-15), and levels of sediment mercury in Lake Pepin (Figure 12-7),
investments in water pollution control programs of the 1970s and 1980s have
succeeded in improving water quality conditions for these historical problems of
the 1950s, 1960s, and 1970s in the Upper Mississippi River. During the 1980s and
1990s, water quality and comprehensive ecological investigations in the Upper
Mississippi River have identified a number of contemporary chemical and
10
Figure 12-15
Long-term trends of mean
summer DO in the Upper
Mississippi River for years
characterized by "dry"
streamflow conditions less
than 75 percent of long-
term (1951-1980) summer
mean streamflow. Data
extracted for subreach
from Newport to Grey
Cloud (UM milepoint 820-
830).
Source: USEPA (STORET).
5-
40 41 48 49 50 58 59 6061 64 67 70 71 73 74 76 7780 87 88 89 90
Dry Years (Flow <75% summer mean)
12-16
-------
Chapter 12: Upper Mississippi River Case Study
nonchemical problems in the basin. Nonchemical issues identified as threats to the
ecological processes of the river and floodplain ecosystem include, for example,
loss of habitat and wetlands and man-made alterations from flood control and
navigation projects. Contemporary chemical problems include inputs of nutrients,
sediments, heavy metals, pesticides, and other toxic chemicals.
For example, the loading of phosphorus and suspended solids influences
water quality in Lake Pepin, a natural impoundment located about 50 miles
downstream of St. Paul. Lake Pepin is eutrophic, with high annual mean concen-
trations of total phosphorus (0.16 mg/L) and soluble reactive phosphorus (SRP)
(0.07 mg/L) (James et al., 1996) recorded at the inlet to the lake (UM milepoint
797) during the average flow years of 1994-1996. Eutrophic conditions in the lake
are caused by excessive loading of nutrients from point and nonpoint sources in
the watershed. When physical and hydrological conditions are favorable, such as
during low-flow summers, nuisance algal blooms (i.e., viable chlorophyll a greater
than 30 ug/L) occur. Concerns related to the need for controls on phosphorus
loading arose after severe algal blooms and fish kills in Lake Pepin occurred
under the drought conditions of 1987-1988 (Johnson, 1999).
The Lake Pepin Phosphorus Study, conducted from 1994-1998, compiled
historical and contemporary data sets to evaluate the human impact on (1) long-
term records of sediment and phosphorus loading to Lake Pepin and (2) the
corresponding water quality responses to changes in loading to the lake. Since
European settlement ca. 1830s, the contemporary (1990-1996) annual input of
approximately 850,000 metric tons/year of sediment is about ten times greater
than the loading rates estimated for the pre-settlement era. Analysis of data from
the three basins included in the study, the Upper Mississippi River, the Minnesota
River and the St. Croix River, indicates that 90 percent of the increased sediment
load to Lake Pepin is contributed by erosion of fine-textured soils from the
Minnesota River basin. The record of sediment deposition in Lake Pepin also
indicates that the most rapid rates of sediment input to the lake occurred during
the 1940s and 1950s. If current sedimentation rates continue from erosion in the
Minnesota River basin, Lake Pepin could be completely filled in about 340 years (
EngstromandAlmendinger, 1998).
Over the past two centuries, phosphorus concentrations in the sediments of
Lake Pepin have increased twofold while water column concentrations (inferred
from diatom assemblages in the sediments) appear to have increased by a factor
of 4 since European settlement ca. 1830s. Increased phosphorus levels in the
sediments and water column are the result of an increase in phosphorus loads to
Lake Pepin by a factor of 5 to 7 since the 1830s to the contemporary estimated
loading rate of approximately 4,000-5,000 metric tons/year for 1990-1996. Waste-
water discharges and agricultural applications of manure and commercial fertilizer
are most likely the key factors controlling historical phosphorus loads to Lake
Pepin, and the statewide ban on phosphates in detergents contributed to a reduc-
tion in phosphorus loading from municipal wastewater plants by approximately 40
percent over the period from 1970 to 1980. Since the 1830s era, the progressive
increase in phosphorus loading has resulted in a shift in assemblages of diatoms
from clear water benthic algae and mesotrophic water column species in the pre-
settlement era to planktonic species exclusively characteristic of highly eutrophic
conditions in the 1990s (Engstrom and Almendinger, 1998).
12-17
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
In evaluating strategies to reduce phosphorus loads to Lake Pepin, the
significant differences in the relative contributions of point and nonpoint sources
of flow, solids, and nutrient loads under a range of flow conditions need to be
considered over a time scale of decades. Point and nonpoint source loading data
for suspended solids and total phosphorus have been compiled for low-flow
(1988), average-flow (1994-1996) and high-flow (1993) conditions for the Upper
Mississippi River (upstream of Lock and Dam No. 1), the Minnesota River, and
the St. Croix River (Meyer and Schellhaass, 1999). Based on 21 years of data
(1976-1996), the mean yield of total phosphorus from the agriculturally dominated
Minnesota River (0.33 Ib/acre-yr) is twice as great as the mean yield from the
Upper Mississippi River basin upstream of Lock and Dam No. 1 (0.16 Ib/acre-yr)
and the St. Croix River basin (0.14 Ib/acre-yr). Figure 12-16 presents a compari-
son of the magnitude of point source loads and nonpoint source loads of total
phosphorus from the Upper Mississippi River, Minnesota River, and St. Croix
River basins for 1988 (drought), 1993 (flood) and 1994-1996 (average conditions)
(Meyer and Schellhaass, 1999).
Under the extreme flood conditions of 1993, nonpoint source loadings of
total phosphorus from the Minnesota River and the Upper Mississippi River
watersheds have been shown to account for 58 percent and 15 percent, respec-
tively, of the total phosphorus load of 6,030 metric tons/yr estimated for 1993
while point sources from the Metro plant accounted for 15 percent of the total
phosphorus load. During the severe drought conditions of 1988, the total phospho-
rus load of 1,900 mt/yr was only about one-third of the 1993 load. Under the
drought conditions, the Metro plant accounted for 47 percent of the total phospho-
rus load and nonpoint source loading from the Minnesota River and the Upper
Mississippi River contributed only 6 percent and 3 percent, respectively, of the
total phosphorus load of 1,900 mt/yr. During the average flow conditions of 1994-
1996, the total phosphorus load of 3,800 mt/yr was two times greater than the
1988 drought load. Under average flow conditions, the Metro plant accounted for
28 percent of the total phosphorus load and nonpoint source loading from the
Minnesota River and the Upper Mississippi River contributed 38 percent and 14
percent, respectively, of the total phosphorus load of 3,800 mt/yr.
eooor
Figure 12-16
Comparison of total
phosphorus loadings from
nonpoint sources (NPS) in
the Upper Mississippi
River (UM, to Lock & Dam
No. 1), Minnesota River
(Ml), and St. Croix River
(SC) basins and point
source (PS) loadings from
the Metro plant and other
facilities in the three river
basins.
Source: Meyer and
Schellhaass, 1999.
Other-PS
Metro-PS
SC-NPS
S3
UM-NPS
•
MI-NPS
1988
1993
1994-96
12-18
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Chapter 12: Upper Mississippi River Case Study
Meyer and Schellhaass (1999) have used this data set to develop summary
budgets of the relative contributions of point source and nonpoint source loadings
of total phosphorus to the three river basins during 1988,1993, and 1994-1996.
Under the drought conditions of 1988, the contribution from point sources (88.5
percent) dominated the total inputs of phosphorus compared to the 11.5 percent
accounted for by nonpoint sources. During the extreme flood conditions of 1993,
nonpoint source loads accounted for about three-quarters (74.5 percent) of the
total input of phosphorus, with point sources accounting for about one-quarter
(25.5 percent). During the average flow conditions of 1994-1996, the relative
contribution of point sources (56.2 percent) and nonpoint sources (43.8 percent)
was almost comparable.
These point source loading and nonpoint source loading data sets for sus-
pended sediments and phosphorus and a number of other field studies (e.g.,
James et al., 1999) have been used to support the development of an advanced
model of sediment transport and eutrophication for the Upper Mississippi River
and Lake Pepin (HydroQual, 1999a, 1999b). As of 2000 the MCES is using the
model to evaluate the effectiveness of alternative strategies to control point and
nonpoint phosphorus loading to the Upper Mississippi River to achieve the water
quality objectives established for Lake Pepin. Evaluations of sediment loading
contributed primarily from agricultural runoff in the Minnesota River basin have
also been a key issue in the Minnesota River Assessment Project (MPCA, 1994).
On the much larger scale of the entire Mississippi River basin, nitrogen
loading from the Mississippi River has been identified as a major cause of the
algal blooms and hypoxia that occur over a 16,000-square-kilometer area of the
inner Gulf of Mexico known as the "Dead Zone" (Christen, 1999; Malakoff, 1998;
Moffatt, 1998; Rabelais et al., 1996; Vitousek et al., 1997). Based on technical
assessments of the "Dead Zone" problem, a U.S. EPA and NOAA Action Plan,
expected to be released in August 2000, will most likely recommend that efforts
be undertaken to reduce inputs of nitrogen from wastewater treatment plants and
agricultural land uses (e.g., fertilizer applications and confined animal feedlots)
over the entire Mississippi River basin, which drains 40 percent of the land area
of the continental United States (Christen, 1999).
The series of locks and dams and maintained navigation channel have been
an integral physical feature of the Upper Mississippi River since the early 1930s
when the U.S. Congress authorized the U.S. Army Corps of Engineers to main-
tain the river for navigation purposes. Concerns have been raised about the
disposal of dredged sediments, often contaminated with heavy metals and toxic
chemicals, to maintain the navigation channel and the loss of ecologically critical
backwater habitats to sediment deposits. The devastation caused by the Great
Flood of 1993 (Wahl et al., 1993) in the upper Midwest has also triggered debates
about the failure of flood control measures intended to protect river communities
from floods. As the key federal agency responsible for inland waterways, the
U.S. Army Corps of Engineers has initiated controversial studies to evaluate the
ecological impact of maintenance dredging, flood control structures, and widening
the series of locks and dams (Phillips, 1999).
12-19
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Evaluation of Water Quality Benefits
Following Treatment Plant Upgrades
From a policy and planning perspective, the central question related to the
effectiveness of the secondary treatment requirement of the 1972 CWA is simply
Would water quality standards for DO be attained if primary treatment levels
were considered acceptable? In addition to the qualitative assessment of
historical data, water quality models can provide a quantitative approach to
evaluate improvements in dissolved oxygen and other water quality parameters
achieved as a result of upgrades to secondary and greater levels of wastewater
treatment. Since the 1970s, increasingly complex models have been developed to
determine wasteload allocation requirements for municipal and industrial discharg-
ers to meet the needs of decision-makers for the Upper Mississippi River.
During the mid-1970s the National Commission on Water Quality (see
NCWQ, 1976) funded Water Resources Engineers (WRE) to develop a steady-
state, one-dimensional water quality model (QUAL-II) of DO, BOD5, nutrients,
and fecal coliform bacteria using data collected in the Upper Mississippi River in
1964-1965 (FWPCA, 1966). The model was applied to evaluate the effectiveness
of the technology-based requirements of the 1972 Clean Water Act for municipal
and industrial dischargers. With funding available from the CWA Section 208
program, Hydroscience (1979) developed a water quality model (AESOP) of DO,
BOD5, nutrients, algae, and bacteria using data collected in 1973, 1976 and 1977.
The model, further validated by the Minnesota Pollution Control Agency using
data obtained in 1980, was used for a wasteload allocation study of the Metro
plant's impact on DO and un-ionized ammonia in Pool 2 (MPCA, 1981).
As a result of the severe algal blooms and fish kills that occurred in Lake
Pepin during the extreme drought of 1988, a time-variable water quality model
(WASP5-EUTRO5) of DO, BOD5, nutrients, and algae was developed using data
collected during 1988 (MWCC, 1989), 1990, and 1991 (EnviroTech, 1992,1993;
Lung and Larson, 1995). The validated model was used to evaluate alternatives
for phosphorus controls at the Metro plant and to perform a post-audit of the
Hydroscience (1979) AESOP model using low-flow data collected during 1988
(Lung, 1996a). The model was also applied to track the fate and transport of
phosphorus and the relative impact of the point and nonpoint sources on eutrophi-
cation in Lake Pepin (Lung, 1996b).
Following completion of the model by EnviroTech (1992,1993), a number of
uncertainty issues were identified related to (1) fate and transport of phosphorus
from point and nonpoint sources; (2) interaction of suspended solids with phospho-
rus transport; and (3) interaction of nonpoint source phosphorus inputs generated
under low-flow and high-flow hydrologic conditions with interannual variation in
the benthic release of phosphorus. To address these issues, a three-dimensional
hydrodynamic, sediment transport, and advanced eutrophication model was
developed and calibrated using data collected over 12 years from 1985 through
1996 (Garland et al., 1999; HydroQual, 1999a, 1999b). The calibrated model was
used to simulate the long-term (24-year) water quality response in the Upper
Mississippi River and Lake Pepin to a number of alternative control scenarios
over a range of hydrologic (e.g., dry and wet years) and loading conditions for
point source and nonpoint source discharges of phosphorus.
12-20
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Chapter 12: Upper Mississippi River Case Study
To evaluate the incremental improvements in water quality conditions that
have been achieved by upgrading municipal wastewater plants from primary to
secondary and from secondary to advanced secondary levels of waste treatment,
Lung (1998) used the WASP5-EUTRO5 model developed by EnviroTech (1992,
1993) to demonstrate the water quality benefits attained by the secondary treat-
ment requirements of the 1972 CWA. Using the model, municipal and industrial
wastewater flow and effluent loading data were used with boundary flow and
loading data describing the Upper Mississippi River and Minnesota River to
compare water quality conditions for three summers (1964, 1976, and 1988)
characterized by comparable low-flow conditions and primary (1964), secondary
(1976), and advanced secondary (1988) levels of wastewater treatment at the
Metro plant. The model was applied to evaluate the water quality impact of three
different treatment levels for Metro and the other municipal plants: (1) primary,
(2) secondary, and (3) advanced secondary with nitrification. CBOD oxidation
rates were calibrated for each of these three different data sets to reflect differ-
ences in the proportion of labile and refractory oxidizeable material discharged
from the Metro plant.
A comparison of the results of the model runs and observed data sets is
presented in Figure 12-17. Spatial distributions of CBOD-ultimate, ammonia-N,
nitrate+nitrite-N, algal chlorophyll, and DO are presented from St. Paul (UM
milepoint 840) to Lock & Dam No. 2 (UM milepoint 815) for 1964 (primary),
1976 (secondary), and 1988 (advanced secondary with nitrification). The upgrade
of the Metro plant from primary to secondary and the corresponding reduction of
effluent BOD5 loading (see Figure 12-9) is reflected in the decrease in ambient
CBOD from a peak of approximately 20 mg/L in 1964 to approximately 7 to 8
mg/L in 1976 at UM milepoint 835 near the Metro plant. As shown in the simula-
tion results, the distributions of ammonia-N and nitrate+nitrite-N are similar under
the primary and secondary treatment scenarios because upgrading from primary
to secondary treatment does not change the effluent concentration of ammonia.
The progressive reduction in ambient ammonia-N and corresponding increase in
ambient nitrate+nitrite-N for the 1988 simulation, however, reflect the impact of
the upgrade from secondary to advanced secondary with nitrification and the drop
in effluent loading of ammonia-N at the Metro plant (see Figure 12-11). During
the 1960s when Metro discharged primary effluent, a large section of the river
was hypoxic or anoxic, with the worst conditions (< 2 mg/L) observed over
approximately 15 miles from UM milepoint 820 to UM milepoint 835. The ob-
served data and the model results indicate the elimination of anoxic conditions and
a nominal improvement in DO conditions under the extreme low-flow conditions
of August 1976. The minimum DO level is increased from approximately 0.5
mg/L in 1964 to approximately 2 mg/L in 1976 as a result of the upgrade from
primary to secondary treatment. Even with secondary treatment at Metro,
however, compliance with the water quality standard for dissolved oxygen of 5
mg/L was not achieved and a distinct oxygen sag is observed in the 1976 data set.
Compliance with the DO standard was finally achieved, even under the extreme
drought conditions of 1988, after Metro was upgraded from secondary to ad-
vanced secondary treatment with nitrification.
The model results demonstrate very clearly the progressive increase in DO
levels in the river following the upgrades at Metro to secondary and advanced
secondary treatment. The model results also demonstrate the ability of a well-
12-21
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
25
' 15
10
S
Primary Treatment
Kd - 0.35 day''
Xunfiltered
0 835 830 825 820 815
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8
835 830 825 820 815
2
$40
835 830 825 820 815
Upper Mississippi River Miles Upper Mississippi River Miles
Legend: { Observed Data (Average and Range) —'— Model Results
$40 835 830 825 820 815
Upper Mississippi River Miles
Figure 12-17
Improvement in ultimate
CBOD, ammonia-N, and
DO levels in the Upper
Mississippi River related to
Metro treatment plant
upgrades from primary to
secondary and advanced
secondary with nitrification.
Source: Lung, 1998.
calibrated model to match observed water quality distributions that are directly
related to changes in effluent loading from Metro under the three different
treatment levels. The data used to define the effluent flow and loading character-
istics for the primary, secondary, and advanced secondary treatment levels for the
1964,1976, and 1988 simulations are given in Lung (1998). The data used to
define effluent flow and loads from the other municipal and industrial point
sources and the boundary inputs from the Upper Mississippi River and the
Minnesota River are summarized by WRE (1975) for 1964 and by EnviroTech
(1992,1993) for the 1976 and 1988 simulations. In generating the simulation
results for the three different treatment scenarios, all model coefficients, except
the CBOD oxidation rate, are based on the same numerical values for each of the
three model runs. The in-stream oxidation rate for CBOD is assigned different
values for primary (0.35 day1), secondary (0.25 day"1), and advanced secondary
with nitrification (0.07 day1) since this kinetic reaction rate is dependent upon
stabilization of the effluent and the quantity of labile and refractory components of
oxidizeable organic matter in the effluent (Chapra, 1997; Thomann and Mueller,
12-22
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Chapter 12: Upper Mississippi River Case Study
1987). Using effluent loading rates that are representative of the three different
treatment levels for Metro, the model results confirm that the improvement in
water quality observed in the Upper Mississippi River can be attributed to invest-
ments in upgrading the Metro plant.
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
Long-term trends in recreational uses, private investments along the
riverfront, and biological resources dependent on the integrity of aquatic ecologi-
cal conditions are meaningful nonchemical indicators of water quality conditions in
the Upper Mississippi River. One very simple indicator is the use of the river for
recreational boating. If water quality conditions are very poor, as was the case
during the 1950s and 1960s, the noxious conditions are not desirable for boating as
a recreational activity. If water quality is not degraded, the river might be consid-
ered desirable for boating. As shown in the long-term trend of recreational boat
traffic through Locks 1 through 4 of the river (Figure 12-18), annual recreational
vessel usage of the river ranged from approximately 25,000 vessels to approxi-
mately 30,000 vessels from the mid-1970s through the mid-1980s. Beginning in
the mid-1980s, the improvements in water quality in the Upper Mississippi River
suggest a strong correlation with the dramatic increase in annual recreational
vessel traffic on the river to approximately 45,000 to approximately 53,000 boats
(Erickson, 2000), with the recreational vessel traffic in Locks 1 through 4 increas-
ing by about two-thirds between 1986 and 1998 (Figure 12-18). Note that traffic
in 1993 dropped by about one-half because of the extreme flood conditions of that
year.
60}
nun nil li
1975
1980
Lock #1
1985
Lock #2 [
1990
Lock #3 j
1995
2000
Lock #4
Figure 12-18
Recreational vessel traffic
in Locks 1 through 4 of the
Upper Mississippi River.
Source: Erickson, 2000.
12-23
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 12-19
Recreational permit
applications for Wabasha,
Dakota, Washington,
Goodhue, Pierce, and
Pepin counties along the
Upper Mississippi River.
Source: Erickson, 2000.
Docks
E3 Beach Improvement
El Wildlife Improvement
D Marinas
Boat Houses
Boat Ramps
D
•81 '82 '83 '84 '85 '86 '87 '88 '89 '90 '91
Year
Recreational boats require marina space, and in 1990 about 2,700 new
marina slips were in various planning stages—enough to double marina capacity.
The number of permit applications received by the St. Paul District U.S. Army
Corps of Engineers for docks, marinas, boathouses, boat ramps, and beach and
wildlife improvements soared from only 3 in 1981 to 22 by 1989 (Figure 12-19). In
the late 1970s, nobody would have considered investing in a marina in Pool 2
because of poor water quality conditions in the vicinity of St. Paul. Apparently
related to improvements in water quality conditions, several marinas were pro-
posed and constructed for this area of the river beginning in the mid-1980s. Lake
City, located on Lake Pepin, for example, obtained a permit for a new marina in
1984; within a year, several hundred spaces were added for sailboats.
Increases in recreational uses of the river prompted eight agencies to form a
partnership agreement in 1990 to study recreational trends and resolve conflicts
over river and parkland use. The agencies included two park services, three state
DNRs, the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers,
and the Minnesota-Wisconsin Boundary Area Commission. They conducted a
study to sort out the issues, uses, and resource management conflicts related to
the rediscovery of the delights of a cleaned-up river by boaters, fishermen, and
hikers (MPCA, 1993).
Partly because of the ban on DDT, the establishment of wildlife reserves,
and reduced loadings of industrial pollutants from the pretreatment program,
populations of water birds have increased in the Upper Mississippi River. Per-
egrine falcons, bald eagles, mallard ducks, and great blue herons have been
observed in the Minneapolis-Saint Paul metropolitan area and in the floodplain
wetlands located on the Upper Mississippi River near the Metro plant. Black
crowned night herons have been observed feeding below the Ford Dam (Galli,
1992). Animals sensitive to the bioaccumulation of PCBs in their aquatic food,
such as fish-eating mink, are also making a comeback (Smith, 1992). The number
of great egrets and great blue herons nesting in Pig's Eye Lake has increased
since the late 1970s and early 1980s, and cormorants has been observed nesting
in the lake since 1983 (Galli, 1992) (Figure 12-20).
12-24
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Chapter 12: Upper Mississippi River Case Study
1 UUU -
800 -
600 -
400 -
200 -
n
- I -
[H Great Blue Herons
- D
i
•^
^
c
Great Egrets
H Cormorants
no nests fl
. , ...i— ..
I i
m
-i^fr*j~
: :
' ' *
.
iiM
n
1 1
m
i_ij
iLJi
rrri
• •:•.
Hall
u^-.
S
Saj
g
m
^
o
\ L
rnn
'^
KB
m
i
Bs
63 64 65 73 78 79 80 81 82 83 84 86 87 88 91 92
Year
in the lake since 1983 (Galli, 1992) (Figure 12-20).
Electrofishing samples from Spring Lake, a backwater area affected by the
Metro plant, were collected in 1981, 1986, and 1991. These samples showed an
increase in the species diversity and the abundance of certain species (Gilbertson,
1992). The ecological quality of Spring Lake, as expressed by the Index of Biotic
Integrety (IBI) (Karr, 1981), has improved since the mid-1980s (Figure 12-21).
Species that have returned to Pool 2 include blue sucker and paddle fish; this is
particularly noteworthy because paddle fish had not been observed in Pool 2 since
the 1950s.
As in many other urban waterways of the United States, detectable levels of
PCBs, a toxic organic chemical that adsorbs to sediment particles, have been
identified in fish tissue and sediments as a result of contamination from industrial
sources, transport of contaminated sediments, atmospheric deposition, storm
water runoff, and wastewater discharges. In 1975 PCB residues found in corn-
Figure 12-20
Colonial bird nest counts
for Pig's Eye Lake.
Source: Galli, 1992,
Figure 12-21
Fish survey results for
Spring Lake, backwater to
Pool 2, which receives
discharges from the Metro
wastewater treatment
plant.
Source: Gilbertson, 1992.
1981
1986
1991 Stream Quality
12-25
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 12-22
Lipid-normalized median
PCB concentrations in fillet
tissue (skin on) of 20-24.9-
inch carp from Pool 2 and
Pool 4 (Lake Pepin) of the
Upper Mississippi River,
1973-1988.
Source: Biedron and
Helwig, 1991.
1 -
Tissue PC
, , . S
w
s -
1 "
n-
|^
I
1
1
n r
1973-74 1975-76 1977-78 1979-80 1981-82 1983-84 1986-86 1987-88
I Pool 2
| | Pool 4 (Lake Pepin)
mon carp and other fish species taken from the Upper Mississippi River exceeded
the FDA action level of 5 mg/kg. The Minnesota Department of Health issued
fish consumption advisories for a number of species including common carp,
catfish, walleye, and smallmouth buffalo (MDH, 1998). Since the ban on produc-
tion of PCBs in 1979, the level of PCBs in fish tissue in the Upper Mississippi
River, as well as in many other rivers and lakes in the United States, has been
declining. In the Upper Mississippi River, median PCB levels in common carp and
walleye dropped by over 80 percent during the period between 1975-1979 and
1988-1995. Dramatic decreases have been recorded in fish tissue levels of PCBs
from common carp collected in Pool 2 and Pool 4 (Lake Pepin) of the river. Lipid-
normalized median PCB concentrations have declined in Pool 2 from 121 ug/g in
1975-1976 to 18 ug/g in 1987-1988 and in Lake Pepin from 62 ug/g in 1973-1974
to 16 ug/g in 1987-1988 (Biedron and Helwig, 1991) (Figure 12-22). Low levels of
PCBs still persist, however, in fish tissue and other chemical pathways in the
aquatic environment, despite the PCB ban (Lee and Anderson, 1998).
Summary and Conclusions
As a result of strong state, local, and federal legislative actions with over-
whelming public support, the cleanup of the Upper Mississippi River in the Twin
Cities area is a national environmental success story. Comprehensive water
pollution surveys dating back to 1926 documented the magnitude of the problems
and provided the technical basis for the implementation of effective engineering
proposals for abatement of water pollution in the river. Since enactment of the
Clean Water Act in 1972, Minnesota has increased the water quality standard for
DO to 5 mg/L and invested in upgrades to obtain better-than-secondary levels of
wastewater treatment for the Metro plant and the other wastewater treatment
plants operated by the MCES.
In contrast to the excessive effluent loading from the Metro plant during the
1960s, the investment in upgrades to the Metro plant during the 1980s, including
nitrification, have succeeded in reducing effluent discharges of BOD5 from 1968
12-26
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Chapter 12: Upper Mississippi River Case Study
to 1998 by 95 percent (Figure 12-9), suspended solids from 1968 to 1998 by 95
percent (Figure 12-10) and ammonia-nitrogen from 1982-1998 by 90 percent
(Figure 12-11). As a direct result of these upgrades, compliance with water
quality standards for DO has been achieved even under the low-flow conditions
of the drought of 1988 (Lung, 1998). The accelerated program to separate storm
water and sanitary flow succeeded in achieving compliance with state standards
(200 MPN/100 mL monthly geometric mean and 2000 MPN/100 mL for indi-
vidual samples) for fecal coliform bacteria at the 71 percent level for samples
collected during 1996-1998. As a result of the industrial waste pretreatment
program initiated in 1982, the discharge of heavy metals to the Metro plant (and
the Upper Mississippi River) has been reduced by about 90 percent (MCES,
1999) and mercury loading from the Upper Mississippi River to Lake Pepin in
1990-1996 declined by almost 70 percent since the 1960s (Balogh et al., 1999).
Despite these significant improvements, MCES has targeted toxic chemicals (e.g.,
PCBs) and heavy metals (e.g., mercury) as contaminants of concern for monitor-
ing, identification of sources, and reduction of the load discharged to the river.
In contrast to the degraded environmental conditions during the 1950s
through 1970s, the Upper Mississippi River is no longer a place to avoid. Parks,
trails, and marinas have been developed along, the river in areas where no one
would have considered making such investments in the 1970s. A thriving
riverfront corridor increases the value of both commercial and residential proper-
ties along the waterfront. The city of St. Paul, for example, through the St. Paul
Riverfront Corporation, has invested nearly $500 million (as of the mid-1990s) for
land acquisitions and infrastructure development along the riverfront (Donlan et
al., 1995). In the late 1980s private developers began to respond to riverfront
infrastructure investments by obtaining more than $7 million in tax increment
financing for development along the riverfront (Donlan et al., 1995). In addition to
private development, in December 1999 the Science Museum of Minnesota
completed a new museum along the riverfront in St. Paul that features exhibits on
the Upper Mississippi River.
The record clearly shows that the Clean Water Act of 1972 profoundly
affected every community in Minnesota, including the Twin Cities. The CWA
accelerated the cleanup of the Upper Mississippi River by providing federal funds
for the construction of new wastewater collection and treatment systems and the
upgrading of existing sewage treatment plants. Since the mid-1980s, the resur-
gence of mayflies and the record of greatly improved compliance with water
quality standards for dissolved oxygen and fecal coliform bacteria are key indica-
tors of the effectiveness of the water pollution control efforts accomplished by
state, federal, and local governments in the Twin Cities.
By the end of 2005, the Metro plant will have implemented biological
removal of phosphorus to meet an annual effluent level of 1 mg/L for phosphorus
(MCES, 1998a). As of 1999 "BioP" had been successfully implemented in a
portion of the Metro plant and at suburban plants discharging to the Minnesota
River. Under the Metro Environment Partnership, the control of urban and rural
runoff will be addressed by a $7.5 million commitment from the MCES to reduce
pollution from the seven-county Twin Cities metropolitan region (MCES, 1998a).
State-of-the-art technology for solids processing, approved in July 1998, will
reduce mercury emissions by 70 percent along with other pollutants and odors
(MCES, 1998a). Further reductions in mercury discharges to the river from the
12-27
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Metro plant will be accomplished as a result of a partnership between the MCES
and the Minnesota Dental Association to test and evaluate new technologies to
filter dental amalgam from wastewater (MCES, 1998b, 2000).
Although significant accomplishments have been made to improve water
quality and ecological conditions in the Upper Mississippi River, continued invest-
ments are needed to address contemporary issues for continued restoration and
maintenance of the ecological integrity of the river. The designation of the Upper
Mississippi River as an American Heritage River in July 1998 recognizes both the
significant environmental improvements that have been accomplished and the
continuing need to address the key ecological issues identified in the 1990s. The
key water quality and resource management issues identified for the Upper
Mississippi River (USGS, 1999b) for the 21 st century include the following:
Point and nonpoint source loading of nutrients, sediments, heavy metals,
and toxic chemicals in the Minnesota River and Upper Mississippi
River from agricultural and urban land uses.
• Point and nonpoint source loading of nutrients and pesticides to aquifer
systems from agricultural land uses.
• Contamination of ground water with toxic chemicals from industrial
activities and leachate from landfills.
• Contamination of surface waters and ground water in areas character-
ized by rapid urbanization.
• Degradation of biological communities by riparian and bottom habitat
losses, river channel modifications, construction of locks and dams,
increasing backwater sedimentation rates and loss of wetlands, effects
of reservoir operations on fisheries, and eutrophication.
• Contamination of bottom sediments in the river with toxic chemicals
and subsequent benthic release and bioaccumulation of toxic sub-
stances within the aquatic food chain.
Water quality in the Upper Mississippi River, as measured by indicators
presented in this chapter such as DO, ammonia, fecal coliform bacteria, and
sediment levels of mercury, has improved greatly since the 1960s and 1970s as a
result of upgrades to wastewater treatment plants required by the 1972 CWA.
Despite these improvements, contaminant loading from municipal (nutrients) and
industrial (heavy metals, toxic chemicals) dischargers and runoff from urban
(heavy metals) and agricultural (nutrients, pesticides, sediments) watersheds
continue to adversely affect the ecological integrity of the Upper Mississippi
River. In addition to chemical inputs to the river, the Upper Mississippi River
Conservation Committee has warned that the ecosystem of the Upper Mississippi
River is threatened by structural alterations of the river such as continued stream
channelization, flood control levees that separate the river from the floodplain, and
the proposed expansion of the commercial navigation infrastructure (UMRCC,
1994). If the current ecological benefits are to be maintained and degraded
ecological conditions restored, an ongoing effort will be needed to maintain
environmental monitoring and research programs to document the status and
trends of the Upper Mississippi River to provide the scientific data needed for
effective resource management decisions (USGS, 1998).
12-28
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Chapter 12: Upper Mississippi River Case Study
References
Balogh, ST., D.R. Engstrom, I.E. Almendinger, M.L. Meyer, and D.K. Johnson.
1999. History of mercury loading in the Upper Mississippi River recon-
structed from the sediments of Lake Pepin. Environ. Sci. Technol. 33(19):
3297-3302.
Berner, E.K., and R.A. Berner. 1996. Global environment water, air and
geochemical cycles. Prentice Hall, Inc., Upper Saddle River, NJ.
Biedron, C.J., and D.D. Helwig. 1991. PCBs in common carp of the Upper
Mississippi River: Investigation of trends from 1973-1988 and the
design of a long term fish monitoring program. Tech. report. Minnesota
Pollution Control Agency, Water Quality Division, St. Paul, MN.
Buttleman, K., and W. Moore. 1999. Update on elevated levels of fecal
coliform bacteria in the Mississippi River above Lock and Dam No.l.
Tech. memorandum to chair and members of the Environment Committee
from Keith Buttleman, Director, Environmental Planning and Evaluation
Dept., MCES, and Bill Moore, Director, Wastewater Services Dept, MCES.
Metropolitan Council Environmental Services, St. Paul, MN. January 18.
Chapra, S.C. 1997. Surface water quality modeling. McGraw Hill, New York,
NY.
Christen, K. 1999. Gulf dead zone grows, perplexes scientists. Environ. Sci.
Technol. News & Research Notes 4(10): 396a-397a.
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extracted from general database that includes data from annual reports of
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January 24,2000.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to
1990. Population Division, U.S. Bureau of the Census, Washington, DC.
.
Fremling, C.R. 1964. Mayfly distribution indicates water quality on the Upper
Mississippi River. Science 146: 1164-1166.
Fremling, C.R., and D.K. Johnson. 1990. Recurrence of Hexagenia mayflies
demonstrates improved water quality in pool 2 and Lake Pepin, Upper
Mississippi River. In Mayflies and Stoneflies, ed. I.C. Campbell, pp. 243-
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FWPCA. 1966. Pollution of the Upper Mississippi River and major tribu-
taries. U.S. Department of the Interior, Federal Water Pollution Control
Administration, Great Lakes Region, Twin Cities Upper Mississippi River
Project, Chicago, IL. NTIS No. PB-217-267.
Galli, Joan. 1992. Minnesota Department of Natural Resources. Personal
communication, November 24,1992.
Garland, E., J.J. Szydlik, D.D. Di Toro, and C.E. Larson. 1999. Framework for
point and non-point source nutrient control evaluations. Presented at
WEFTEC'99, October 9-13, 1999, New Orleans, LA. Water Environment
Federation, Alexandria, VA.
Gilbertson, B. 1992. Minnesota Department of Natural Resources, Fisheries
Metro Office. Personal communication, September 11, 1992.
HydroQual. 1999a. Advanced eutrophication model of the Upper Mississippi
River, Summary Report. Draft report prepared for Metropolitan Council
Environmental Services, St. Paul, MN, by HydroQual, Inc., Mahwah, NJ.
April.
HydroQual. 1999b. Advanced eutrophication model of Pooh 2 to 4 of the
Upper Mississippi River. Draft report prepared for Metropolitan Council
Environmental Services, St. Paul, MN, by HydroQual, Inc., Mahwah, NJ.
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Hydroscience. 1979. Upper Mississippi River 208 Grant water quality
modeling study. Tech. report prepared for Metropolitan Waste Control
Commission, St. Paul, MN, by Hydroscience. August.
Iseri, K.T., and W.B. Langbein. 1974. Large rivers of the United States.
Circular No. 686. U.S. Department of Interior, U.S. Geological Survey.
James, W.F., J.W. Barko, and H.L. Eakin. 1996. Analysis of nutrient/seston
fluxes and phytoplankton dynamics in Lake Pepin (Upper Mississippi
River), 1996: Third Annual Report. Tech. report submitted to Metro
Council, St. Paul, MN.
James, W.F., J.W. Barko, and H.L. Eakin. 1999. Diffusive and kinetic fluxes
of phosphorus from sediments in relation to phosphorus dynamics in
Lake Pepin, Upper Mississippi River. Misc. Paper No. W-99-1. U.S.
Army Corps of Engineers, Engineering Research and Development Center,
Vicksburg, MS.
Johnson, D.K. 1999. Environmental studies of phosphorus in the Upper
Mississippi River, 1994-1998. Presented at Mississippi River Research
Consortium, Annual Meeting, La Crosse, WI, April 22-23,1999.
Johnson, D.K., and P.W. Aasen. 1989. The metropolitan wastewater treatment
plant and the Mississippi River: 50 years of improving water quality. J. Minn.
Acad. Sci. 55(1):134-138.
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Chapter 12: Upper Mississippi River Case Study
Karr, J.R. 1981. Assessment of biotic integrity using fish communities. Fisheries
6(6): 21-27.
Larson, C.E. 1999. Metropolitan Council Environmental Services, St. Paul,
Minnesota. Personal communication, March 12,1999.
Lee, K.E., and J.P. Anderson. 1998. Water quality assessment of the Upper
Mississippi River Basin, Minnesota and Wisconsin—Polychlorinated
Biphenyls in common carp and walleye fillets, 1975-95. U.S. Geological
Survey. Originally published as Water Resources Investigations Report 98-
4126. USGS Water Resources in Minnesota web site, .
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J. Environ. Eng. 122(5): 350-358.
Lung, W. 1996b. Fate and transport modeling using numerical tracers. Water
Resources Research 32(1): 171-178.
Lung, W. 1998. Trends in BOD/DO modeling for waste load allocations. ASCE
J. Environ. Eng. 124(10): 1004-1007.
Lung, W, and C. Larson. 1995. Water quality modeling of Upper Mississippi
River and Lake Pepin. ASCE J. Environ. Eng. 121(10): 691-699.
Malakoff, D. 1998. Death by suffocation in the Gulf of Mexico. Science 281
(JulylO): 190-192.
MCES. 1996. Separating combined sewers to improve and protect Missis-
sippi River water quality: A ten-year commitment. Annual Progress report
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apolis, St. Paul, and South St. Paul, and Metropolitan Council Environmental
Services, St. Paul, MN.
MCES. 1998a. Update (newsletter). Metropolitan Council Environmental
Services, St. Paul, MN. August 3 and November 25 issues.
MCES. 1998b. Protecting our future. Biennial Report 1996-98. Metropolitan
Council Environmental Services, St. Paul, MN. September.
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mental Services, St. Paul, MN. January/February.
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Department of Health, St. Paul, MN.
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Mississippi River Water Quality. Presented at Mississippi River Research
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Mockovak, C. 1990. Mississippi River water quality mirrors metro area history.
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St. Paul, MN.
Moffat, A. 1998. Global nitrogen overload problem grows critical. Science
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St. Paul, MN.
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MPCA. 1993. Mississippi River phosphorus study, section 8 benefit inven-
tory report. Tech. report prepared by Water Quality Division, Minnesota
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12-32
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Chapter 12: Upper Mississippi River Case Study
USEPA (STORET), STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
watersheds, Washington, DC.
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12-34
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Chapter 13
Willamette
River
Study
The Pacific Northwest
basin, covering a drainage
area of 277,612 square miles,
includes the "mighty" Columbia
River. Based on its annual discharge
(262,000 cfs, 1941 -1970), the Columbia is
the second largest river in the continental United
States (Iseri and Langbein, 1974). With a length of 270
miles, a drainage area of 11,200 square miles, and a mean
annual discharge of 35,660 cfs (1941-1970), the Willamette River
is the 15th largest waterway in the United States ranked on the basis
of annual discharge (Iseri and Langbein, 1974). Figure 13-1 highlights
the location of the Willamette River case study watersheds (catalog
units) identified in the Pacific Northwest basin as major urban-industrial
areas affected by severe water pollution problems during the 1950s and
1960s (see Table 4-2). In this chapter, information is presented to charac-
terize long-term trends in population, municipal wastewater infrastructure and
effluent loading of pollutants, ambient water quality, environmental resources, and
uses of the Willamette River. Data sources include USEPA's national water
quality database (STORET), published technical literature, and unpublished
technical reports ("grey" literature) obtained from local agency sources.
The Willamette River extends for 270 miles from its headwaters in the
southern Cascade Mountains in Douglas County, Oregon, to the city of Portland,
Oregon, where it meets the tidal Columbia River (Figure 13-2) (Iseri and
Langbein, 1974). More than two-thirds of Oregon's population lives within the
major urban centers that have developed in the valley. The basin provides exten-
sive natural habitat for fish and wildlife and supports a prosperous economy based
on agriculture, timber and wood products, and recreation.
Figure 13-1
Hydrologic Region 17 and
Willamette watersheds.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
124°
123°
122°
Figure 13-2
Location map of
Willamette River Basin.
River miles shown are
distances from the
confluence of the
Willamette River with the
Columbia River at
Portland, OR.
46°
45°
44C
IN
A
46°
45°
44°
124°
123°
122°
The Willamette River was once one of the Nation's most grossly polluted
waterways because of raw sewage discharges and inadequate levels of municipal
and industrial waste treatment. Since the late 1920s, when a survey found that
nearly half of the citizens of Portland were in favor of antipollution laws, public
opinion in Oregon has strongly favored regulatory controls on waste discharges to
clean up the Willamette River. As a result of strong legislative actions with
overwhelming public support, the cleanup has become a major national environ-
mental success. In particular, Oregon's legislative actions mandating a minimum
level of secondary waste treatment have played an important role in restoring the
ecological balance of the Willamette.
Physical Setting and Hydrology
With a watershed of 11,200 square miles, the Willamette River basin in
northwestern Oregon is bounded by the Coast (west) and Cascade (east) moun-
tain ranges which have a north-south length of 150 miles and an east-west width
of 75 miles (Figure 13-2). Elevations range from less than 10 feet at the mouth
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Chapter 13: Willamette River Case Study
Table 13-1. Physical characteristics of Willamette River at 6,000 cfs.
Source: Rickert et ai, 1976.
Reach
Upstream
Newberg Pool
Tidal
Length
(miles)
135.0
25.5
26.5
Average
Velocity
(cm/sec)
60
8
3
Travel
Time
(days)
2.8
3.9
10.0
near the Columbia River to 450 feet in the valley near Eugene to greater than
10,000 feet in the headwaters of the Cascade mountain range. Physical transport
in the river can be described in terms of three distinctive physiographic reaches
and characterized by the key physical parameters that strongly influence water
quality—length, summer low-flow velocity, and travel time (Table 13-1). The
longer travel time in the tidal portion of the Willamette River (10 days) can lead to
decreased water quality.
Seasonal variation in the river flow is the result of the region's heavy winter
rains and spring snowmelt from November through March. Low-flow conditions
occur during the summer months of July through September, with the seasonal
minimum occurring during August. Based on data from 1940-1990, monthly
average flows range from 6,246 cfs in August to 48,060 cfs in January (Figure
13-3). Before 1953, the natural summer low flow ranged from 2,500 cfs to 5,000
cfs at Salem. Since 1953 flow augmentation by 14 U.S. Army Corps of Engineers
(USAGE) reservoirs has been used to maintain a summer low flow of about 6,000
cfs at Salem (Mines et al., 1976) (Figure 13-4).
Figure 13-3
Monthly variation of flow of
the Willamette River at
Salem, Oregon (Gage
#14191000), 1951-1980.
Source: USGS, 1999.
ONDJFMAMJJAS
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 13-4
Long-term trends of
summer flow of the
Willamette River at Salem,
Oregon (Gage
#14191000), July-
September.
Source: USGS, 1999.
2.00
-1.50
CO
DC
1950
1960 1970 1980 1990
-1.00
-0.50
0.00
90%ile
mean & ratio
Population, Water, and Land Use Trends
Because of abundant natural resources, the river has played a key historical
role in the agricultural and industrial development of the valley. The Willamette
River, a major source for the basin's municipal (20 cities) and industrial (600
facilities) water supply, also provides irrigation water for the rich fruit and veg-
etable farms of the valley. Other major uses include commercial navigation,
hydroelectric power production, commercial and recreational fisheries, and water-
based recreational activities, including aesthetic enjoyment of the Greenway Trail
along the length of the river. As the region has grown, the river has also been
used—and misused—for municipal and industrial waste disposal, including the
disposal of wastewater generated by the pulp and paper industry since the 1920s.
Oregon's three largest cities—Salem, Portland, and Eugene—with a total
population of 1.8 million (nearly 70 percent of the state's population) are within
the Willamette River basin. The population of the basin has steadily increased
since World War II. With a significant wood products and agricultural economy,
the Willamette basin accounts for about 70 percent of the total industrial produc-
tion of Oregon. Industrial production, like the population of the basin, has steadily
increased over the past several decades.
The Willamette River case study area includes a number of counties identi-
fied by the Office of Management and Budget (OMB) as Metropolitan Statistical
Areas (MSAs) or Primary Metropolitan Statistical Areas (PMSAs). Table 13-2
lists the MSAs and counties included in this case study. Figure 13-5 presents long-
term population trends (1940-1996) for the counties listed in Table 13-2. From
1940 to 1996 the population in the area more than tripled (Forstall, 1995; USDOC,
1998).
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Chapter 13: Willamette River Case Study
Table 13-2. Metropolitan Statistical Area (MSA) counties in the Willamette River
case study. Source: OMB, 1999.
Portland-Salem, OR-WA CMSA
Clackmas, OR
Columbia, OR
Multnomah, OR
Washington, OR
Yamhill, OR
Clark, WA
Marion, OR
Polk, OR
Corvallis, OR MSA
Benton, OR
2,
Figure 13-5
Long-term trends in
population in the
Willamette River Basin.
Sources: Forstall, 1995;
USDOC, 1998.
0.'
1940 1950 1960 1970 1980 1990 1996
Historical Water Quality Issues
In the early 1920s, the Oregon Board of Health determined that the Lower
Willamette River near Portland was grossly polluted as a result of raw waste
discharges from municipal and industrial sources. In 1927, the Portland City Club
declared the Willamette "ugly and filthy" with "intolerable" conditions. The first
comprehensive water quality survey in 1929 found severely declining oxygen
levels downstream of Newberg with an estimated concentration of 0.5 mg/L at
the confluence with the Columbia River. Not surprisingly, bacteria levels were
also found to be significantly increased downstream of each major city along the
river. Industrial disposal from pulp and paper mills had resulted in extensive
bottom sludge deposits that frequently surfaced during summer low-flow condi-
tions as noxious, unsightly floating mats of sludge. By 1930 the municipal waste
from the 300,000 inhabitants of Portland flowed untreated into Portland Harbor,
resulting in severe oxygen depletion during the summer (Oregon State Sanitary
Authority, 1964;Gleeson, 1972).
During the 1950s Kessler Cannon, a state official, described the Willamette
River from Eugene to the Columbia River as the "filthiest waterway in the
Northwest and one of the most polluted in the Nation." Gross water pollution
conditions resulted in high bacteria counts, oxygen depletion, and fish kills (e.g.,
Gleeson and Merryfield, 1936; Merryfield et al., 1947; Merryfield and Wilmot,
1945). Cannon recounted the noxious conditions in the Willamette: "As the
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
bacteria count rose, oxygen levels dropped—to near zero in some places. Fish
died. The threat of disease put a stop to safe swimming. Rafts of sunken sludge,
surfacing in the heat of summer, discouraged water-skiing and took the pleasure
out of boating" (Starbird and Georgia, 1972). In 1967 the Izaak Walton League
described the Lower Willamette River as a "stinking slimy mess, a menace to
public health, aesthetically offensive, and a biological cesspool" (USEPA, 1980).
Legislative and Regulatory History
After more than a decade of public concern about the polluted conditions of
the Willamette River, the citizens of Oregon passed a referendum in 1938 setting
water quality standards and establishing the Oregon State Sanitary Authority.
With the establishment of the Sanitary Authority, it became Oregon's public policy
to restore and maintain the natural purity of all public waters. As a result of
regulatory actions by the Sanitary Authority, all municipalities discharging into the
Willamette implemented primary treatment during the period from 1949 to 1957,
with all costs borne by the municipalities. Beginning in 1952 industrial waste
discharges from the pulp and paper mills were controlled by required lagoon
diversions during summer months. In 1953 the new USAGE dams began to
operate, resulting in augmentation of the natural summer low flow. Although not
originally planned for water quality management, summer reservoir releases have
become a significant factor in maintaining water quality and enabling salmon
migration during the fall.
Although tremendous accomplishments had been made in controlling water
pollution in the Willamette basin, large increases in industrial production and in the
population served by municipal wastewater plants exceeded the assimilative
capacity of the river. By 1960 the Sanitary Authority required that all municipali-
ties discharging to the Willamette River achieve a minimum of secondary treat-
ment (85 percent removal of BOD5). In 1964 the pulp and paper mills were
directed to implement primary treatment, with secondary treatment during the
summer months. In 1967, industrial secondary treatment was required on a year-
round basis. The Sanitary Authority had thus established a minimum policy of
secondary treatment for all municipal and industrial waste dischargers with the
option of requiring tertiary treatment if needed to maintain water quality. The state
initiated the issuance of discharge permits for wastewater plants in 1968, 4 years
before the 1972 CWA established the National Pollutant Discharge Elimination
System (NPDES). The policy adopted in 1967 remains the current water pollution
control policy of the state of Oregon for the Willamette River (ODEQ, 1970).
In response to the 1965 Federal Water Quality Act, Oregon established
intrastate and interstate water quality standards in 1967 that were among the first
new state water quality standards to be approved by the federal government. The
1972 CWA provided even further authority for Oregon to issue discharge permits
limiting the pollutant loading of municipal and industrial facilities.
From 1956 to 1972, Federal Construction Grants to Oregon totaled $33.4
million for municipal wastewater facilities (CEQ, 1973). Since 1974 the cities of
Salem, Corvallis, and Portland have received Construction Grants under the 1972
CWA to build and upgrade secondary waste treatment facilities.
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Chapter 13: Willamette River Case Study
Impact of Wastewater Treatment:
Pollutant Loading and Water
Quality Trends
As a result of the stringent regulatory requirements for municipal and
industrial waste treatment, total pollutant loading has decreased substantially over
the past 30-40 years (Figure 13-6) while total wastewater flow has increased
over the same period. By 1972, when the CWA was passed, the total oxygen
demand of wastewater discharges to the Willamette had been decreased to 25
percent of the demand of the pollutant load discharged in 1957 (CEQ, 1973).
Following the implementation of basinwide secondary treatment for municipal and
industrial wastewater sources, water quality model budgets have shown that
about 46 percent of the oxygen demand in the Willamette River during the critical
summer months results from upstream nonpoint source loads from rural tributary
basins. The remaining half of the total oxygen demand is accounted for by
municipal (22 percent) and industrial (32 percent) point source loads (Rickert and
Mines, 1978).
Severe summer oxygen depletion has been the key historical water quality
problem in the Willamette River. Over the past 20 years, however, summer
oxygen levels have increased significantly as a result of (1) the implementation of
basinwide secondary treatment for municipal and industrial point sources and
(2) low flow augmentation from reservoir releases. Based on data obtained from
the earliest water quality survey in 1929 to the most recently available monitoring
programs, the dramatic improvements in summer oxygen levels in the river are
clearly shown in the spatial distribution of oxygen from Salem to Portland Harbor
(Figure 13-7) and the long-term historical trend for oxygen in the lower Willamette
River near Portland Harbor (Figure 13-8). These historical data sets document
the grossly polluted water quality conditions that existed prior to implementation of
a minimum level of secondary treatment for municipal and industrial discharges to
the river.
700
1940
Year
I Municipal
Mun + Industrial
Figure 13-6
Long-term trends in
municipal and industrial
effluent BOD5 loading to
the Willamette River.
Source: Gleeson, 1972;
ODEQ, 1970.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Figure 13-7
Long-term trends in the
spatial distribution of DO in
the Willamette River.
Source: Rickert, 1984.
-80
-60 -40
Miles from Columbia River
-20
Figure 13-8
Long-term trends in
summer DO in the Lower
Willamette River at
Portland, OR, for RF reach
17090012017 (mile 0-
15.7).
Source: USEPA (STORET).
'1950' ' " ' ' 'I'g'eb' 1970 1980
Portland - Milwaukie OR (Mile 0-15.7)
1990
Although the current status of the river is visibly much improved and water
contact sports and salmon migration are once again possible in most of the river,
there are still concerns about the levels of toxic contamination. Oregon's 1990
water quality status assessment report (ODEQ, 1990a) classified the river as
"water quality limited" as a result of seven contaminants exceeding USEPA draft
sediment guidelines (arsenic, chromium, lead, zinc, and DDT), state water quality
standards (arsenic), or both (2,3,7,8-TCDD). Surveys have found levels of toxic
chemicals in water, sediments, and fish tissue at various locations in the river
basin (ODEQ, 1994). Surveys conducted by ODEQ in 1994 indicated that levels
of metals (arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel,
silver, and zinc), pesticides (chlordane and DDT), other organic chemicals (carbon
tetrachloride, creosote, dichloroethylene, dioxin, PAHs, PCBs, phenol, pentachlo-
rophenol, phenanthrene, phthalates, trichloroethane, trichloroethylene, and
trichlorophenol), and bacteria exceed regulatory or guidance criteria for the
protection of aquatic life and human health in at least one location of the river.
As a result of these findings, in 1990 the Oregon legislature directed ODEQ
to develop a comprehensive study that would generate a technical and regulatory
understanding and an information base on the river system that could be used to
protect and enhance its water quality. To meet this directive, ODEQ developed
and implemented a comprehensive, multiphase investigation known as the
Willamette River Basin Water Quality Study (WRBWQS) (ODEQ, 1990b; Tetra
Tech, 1995).
13-8
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Chapter 13: Willamette River Case Study
Impact of Wastewater Treatment:
Recreational and Living Resources
Trends
The first comprehensive study of the Willamette River biota was conducted
by Dimick and Merryfield (1945) in the summer of 1944. Their study was specifi-
cally intended to assess the impact of water pollution on fish and benthic inverte-
brates in the river. Benthos are particularly good indicators of long-term trends in
water quality because most benthic species are sedentary and have long life
spans. Their state of health is therefore a gauge of both past and present water
quality. Reactions to even occasional toxic discharges are measurable as vari-
ances in the species assemblages of benthic invertebrates. For pollution studies,
benthos are divided into three categories: (1) intolerant species (e.g., stoneflies,
mayflies, caddisflies) are indicative of good water quality because of their inability
to survive in or tolerate low DO concentrations; (2) facultative species are
indicative of a transition between good and poor water quality because they can
survive under a wide range of DO conditions; and (3) tolerant species (e.g.,
sludgeworms), which are adapted to low DO levels, become dominant where
poor water quality is prevalent.
Dimick and Merryfield (1945) found very different biological conditions in
different stretches of the river. Upstream of Salem, where pollutant sources to the
river were few, they found an abundance of healthy fish and populations of
intolerant caddisfly, mayfly, and stonefly nymphs (Figure 13-9). From below
Salem to Portland, where pollutant loadings to the river were greatest, they found
few to no fish, dead fish in or on the banks of the river, and a total absence of
stoneflies and mayflies. They further noted that the biomass of insect larvae
downstream of Salem was less than that upstream, and that largemouth bass
collected below Salem were generally smaller than normal and in poor physical
condition. Both of these conditions are indicative of poor water quality.
Figure 13-9
Spatial distribution of
tolerant and intolerant
benthic organisms in the
Willamette River upstream
and downstream of
municipal waste
discharges in 1945.
Source: Dimick and
Merryfield, 1945.
SB WF NE OC
Location on Willamette River
PO
SA=Salem (1 mile above city); SB=Salem (2 miles below city); WF=Wheatland Ferry; NE=Newberg
(0.8 miles above city); OC=Oregon City (above and below Willamette Falls); PO=Portland (0.3 miles
upstream of Sellwood Bridge)
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Dimick and Merryfield attributed the poor biological condition below Salem
to the effects of pollution, but it is uncertain whether fish were directly affected or
whether their populations were diminished because of the lack of their inverte-
brate foodstuffs (Dimick and Merryfield, 1945). Regardless, the study demon-
strated that pollution was a major factor in the decline of the river's commercial
and sport fisheries.
In 1983 the study was repeated to assess the changes that had occurred in
the river since its cleanup began. Hughes and Gammon (1987) sampled the same
sites that Dimick and Merryfield had sampled in 1944. Although the 1983 study
showed some signs of a pollution-stressed river below Salem, the differences
between the findings of the studies demonstrated a marked improvement in water
quality. Where Dimick and Merryfield had found only tolerant species associated
with sluggish, warm water and muddy or sandy substrates, Hughes and Gammon
found many intolerant species suited to fast-moving, cold water and rubble and
gravel bottoms.
The improvements in the fish communities of the Willamette River between
1944 and 1983 (Figure 13-10) were not solely due to water quality improvements.
Historically, the river provided important spawning and nursery grounds for
salmon and steelhead, but dams built along the river prevented these fish from
reaching their spawning grounds. Corrections to this situation have accompanied
water quality improvements. Fish ladders have been built at dams, and four large
fish hatcheries have been put into operation, producing 3.8 million salmon per year
(Bennett, 1991). The dams also provide flow augmentation during autumn low-
flow periods, thereby providing faster moving, oxygenated water to running fall
chinook salmon (Starbird and Georgia, 1972).
Water quality has nevertheless played an important role in the survival and
return of both natural-born and hatchery-reared salmon in the Willamette River. In
1965 only 79 chinook salmon were counted in the fall run. That number increased
to 5,000 in 1971 (Starbird and Georgia, 1972). A record high of 106,300 spring
chinook salmon were counted in the 1990 run, up 30 percent from the 1985-1989
average of 81,900. The 1990 catch of chinook salmon of 27,700 was 39 percent
greater than the 1980-1989 average of 20,000 (Bennett, 1991). With the recent
and continuing population growth in the Portland area (where most of the salmon
are caught) and water quality improvements, interest in angling in the river has
increased dramatically. The Willamette River is once again able to support
important commercial and recreational fisheries.
Figure 13-10
Long-term trends of spring
chinook salmon runs.
Source: Bennett, 1991.
• Annual Catch 10-Year Average
1960 1970 1980 1990
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Chapter 13: Willamette River Case Study
Summary and Conclusions
The cleanup of the Willamette River has been accomplished because of
overwhelming public support; strong commitment by federal, state, and local
governments; comprehensive water quality studies that documented the extent of
the problems; and the implementation of sound engineering proposals for control-
ling water pollution. Public pressure and responsive political leadership have
resulted in the basinwide implementation of secondary treatment requirements
with a minimum of legal actions needed to ensure compliance with the regula-
tions. Water quality studies of the Willamette (e.g., Rickert, 1984; Rickert et al.,
1976) have demonstrated the importance of the minimum requirement of second-
ary waste treatment for municipal and industrial dischargers, as well as the
significance of background water quality and summer low-flow augmentation
from USAGE reservoirs, in achieving Oregon's water quality goals.
Vast improvements in the water quality of the Willamette River, facilitated
by stringent regulatory controls, have led to remarkable improvements in the
integrity of the river's biological communities. Of major importance, both
recreationally and economically, is the continuing recovery of the fisheries.
Salmon and steelhead on their migratory spawning runs are no longer precluded
from reaching their spawning grounds in the Willamette River basin because of
severely depressed or nonexistent concentrations of DO. Recreational anglers are
once again able to enjoy pursuing these valuable gamefish as the fish make their
way up the river to their spawning grounds. Another significant improvement is
the return of viable populations of resident species of gamefish, including bass,
catfish, perch, sturgeon, and crappies.
Although the severe water quality problems that have plagued the
Willamette River in the past are clearly gone, there are still reasons for concern
about the river's overall health (Tetra Tech, 1995). Until the continued presence
of toxic contaminants in the water and sediments, the loads of suspended sedi-
ment and nutrients, and the alteration of the habitat can be abated, the overall
ecological conditions of the Willamette River will continue to suffer.
For four decades beginning in the 1920s the Lower Willamette River near
Portland, Oregon, was considered one of the most polluted urban-industrial rivers
in the United States. In 1927 the Portland City Club declared the Willamette River
"ugly and filthy...with intolerable conditions." During the 1950s the Willamette
River was described as the "filthiest waterway in the Northwest and one of the
most polluted in the Nation." In 1967 the Izaak Walton League described the river
as a "stinking slimy mess, a menace to public health, aesthetically offensive and a
biological cesspool."
Three decades after enactment of strict water pollution control regulations
by the state of Oregon in the late 1960s and the federal Clean Water Act in 1972,
the remarkable improvements in water quality and the ecological health of the
river now provide important recreational and commercial benefits to the citizens
of the Willamette valley. Salmon and steelhead fisheries, once blocked by dams
without fish ladders and constrained by low dissolved oxygen conditions, are now
sustained by migratory populations that can safely reach upriver spawning
grounds. The local economies of major cities on the Willamette River are thriving,
and upscale developments are attracted to riverfront locations by the aesthetics of
a clean river that was once considered noxious with an unsightly riverfront.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Although the gross water pollution problems of the first half of the 20th century
have been eliminated, nutrient enrichment, sediment loading, and the lingering
presence of toxic chemicals in the river, sediment bed, and biota are ecological
problems that remain. Hopefully, they will be addressed in the early decades of
the 21 st century.
References
Bennett, D.E. 1991. 1990 Willamette River spring Chinook salmon run.
Oregon Department of Fish and Wildlife, Columbia River Management.
November.
CEQ. 1973. Chapter 2 in Cleaning up the Willamette. Fourth annual report on
environmental quality. Council on Environmental Quality, Washington, DC.
Dimick, R.E., and F. Merryfield. 1945. The fishes of the Willamette River
system in relation to pollution. Oregon State College Engineering Experi-
ment Station. Bulletin Series No. 20. June.
Forstall, R.L. 1995. Population by counties by decennial census: 1900 to
1990. Population Division, U.S. Bureau of the Census, Washington, DC.
.
Gleeson, G.W. 1972. The return of a river, the Willamette River, Oregon.
Oregon State University, Corvallis, OR.
Gleeson, G.W., and F. Merryfield. 1936. Industrial and domestic wastes of the
Willamette Valley. Engineering Experiment Station Bulletin No. 7. Oregon
State Agricultural College, Corvallis, OR.
Hines, W.G., D.A. Rickert, and S.W. McKenzie. 1976. Hydrologic analysis
and river quality data programs. U.S. Geological Survey Circular 715-D.
U.S. Department of the Interior, Arlington, VA.
Hughes, R.M., and J.R. Gammon. 1987. Longitudinal changes in fish assem-
blages and water quality in the Willamette River, Oregon. Trans. Am. Fish.
Soc. 116: 196-209.
Iseri, K.T., and W.B. Langbein. 1974. Large rivers of the United States.
Circular No. 686. U.S. Department of the Interior, U.S. Geological Survey,
Arlington, VA.
Merryfield, F., and W.G. Wilmot. 1945. 7945 progress report on pollution in
Oregon streams. Engineering Experiment Station Bulletin No. 19. Oregon
State University, Corvallis, OR.
Merryfield, F., W.B. Bollen, and F.C. Kachelhoffer. 1947. Industrial and city
wastes. Engineering Experiment Station Bulletin No. 22. Oregon State
University, Corvallis, OR.
ODEQ. 1970. Water quality control in Oregon. December. Oregon Depart-
ment of Environmental Quality, Portland, OR.
ODEQ. 1990a. Oregon 1990 water quality status assessment report: 305(b)
report. Prepared for U.S. Environmental Protection Agency by Oregon
Department of Environmental Quality, Portland, OR.
ODEQ. 1990b. Willamette River basin water quality study: Rationale for a
draft work plan. Oregon Department of Environmental Quality, Portland,
OR.
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Chapter 13: Willamette River Case Study
ODEQ. 1994. Oregon's 1994 water quality status assessment report: 305
(b) report. Prepared for U.S. Environmental Protection Agency by Oregon
Department of Environmental Quality, Portland, OR.
OMB. 1999. OMB Bulletin No. 99-04. Revised statistical definitions of Metro-
politan Areas (MAs) and Guidance on uses of MA definitions. U.S. Census
Bureau, Office of Management and Budget, Washington, DC. .
Oregon State Sanitary Authority. 1964. Report on water quality and waste
treatment needs for the Willamette River. Division of the State Board of
Health, Portland, OR. May.
Rickert, D.A. 1984. Use of dissolved oxygen modeling results in the manage-
ment of river quality. J. WPCF 56(1): 94-101.
Rickert, D.A., W.G. Mines, and S.W. McKenzie. 1976. Methodology for river
quality assessment with application to the Willamette River Basin,
Oregon. U.S. Geological Survey Circular 715-M. U.S. Department of the
Interior, Arlington, VA.
Rickert, D.A., and W.G. Hines. 1978. River quality assessment: Implications of
a prototype project. Science 200 (June 9, 1978): 1113-1118.
Starbird, E.A., and L.J. Georgia. 1972. A river restored: Oregon's Willamette.
National Geographic 141(6): 816-835.
Terra Tech. 1995. Willamette River basin water quality study: Summary and
synthesis of study findings. Prepared for Oregon Department of Environ-
mental Quality, Water Quality Division, Portland, OR, by Terra Tech, Inc.,
Redmond, WA.
USDOC. 1998. Census of population and housing. U.S. Department of
Commerce, Economics and Statistics Administration, Bureau of the Census -
Population Division, Washington, DC.
USEPA. 1980. National accomplishments in pollution control: 1970-1980.
U.S. Environmental Protection Agency, Office of Planning and Evaluation,
Washington, DC.
USEPA (STORET). STOrage and RETrieval Water Quality Information System.
U.S. Environmental Protection Agency, Office of Wetlands, Oceans, and
watersheds, Washington, DC.
USGS. 1999. Streamflow data downloaded from the U.S. Geological Survey's
National Water Information System (NWIS)-W Data retrieval for historical
streamflow daily values, .
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13-14
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Appendix A
Summary of Peer Review
Team Comments and Study
Authors' Responses
The Peer Review Team consisted of the following individuals.
Mr. Leon Billings
Mr. Tom Brosnan, National Oceanic and Atmospheric Administration
Mr. Michael Cook, U.S. Environmental Protection Agency
Mr. John Dunn, U.S. Environmental Protection Agency
Dr. Mohammad Habibian, Washington Suburban Sanitation Commission
Dr. Leo Hetling, Public Health and Environmental Engineering, New York State Department
of Environmental Conservation (retired)
Dr. Russell Isaacs, Massachusetts Department of Environmental Protection
Dr. Norbert Jaworski, U.S. Environmental Protection Agency (retired)
Dr. William Jobin, Blue Nile Associates
Mr. Ken Kirk, American Metropolitan Sewerage Association
Mr. John Kosco, U.S. Environmental Protection Agency
Mr. Rich Kuhlman, U.S. Environmental Protection Agency
Mr. Joseph Lagnese
Ms. Jessica Landman, National Resource Defense Council
Mr. Kris Lindstrom, K.P. Lindstrom, Inc.
Mr. Ronald Linsky, National Water Research Institute
Dr. Berry Lyons, University of Alabama
Dr. Alan Mearns, National Oceanic and Atmospheric Administration
Dr. Daniel Okun, University of North Carolina
Mr. Steve Parker, National Research Council
Mr. Richard Smith, U.S. Geological Survey
Mr. Phill Taylor, U.S. Environmental Protection Agency and Tetra Tech, Inc. (retired)
Dr. Red Wolman, Johns Hopkins University
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Appendix A: Summary of Peer Review Team Comments and Study Authors' Responses
EPA Instructions to Peer Review Team for Evaluation of
Draft Report Dated October 18,1998
• Feedback on accuracy and historical context of statements in the report.
• Evaluation of the reliability of the statistical techniques used to document "before and after" trends
in dissolved oxygen.
• Have we overlooked any significant work in the literature relevant to the study?
• Have we missed anything in interpretations of "before and after" data in relation to the historical
context of water pollution control activities in the United States?
• Has the study met the stated objective of identifying national-scale progress in water quality
achieved as a result of EPA's investment in water pollution control infrastructure?
The following key issues were identified in the responses received from 21 members of the Peer Review
Team. For each key issue, a summary of the major points raised by the members of the Peer Review Team is
presented along with our responses to the issue and where the relevant information is presented in the final
report.
Key Issues Identified by Peer Review Team
1. Target audience
2. Title of final report and objectives of the study
3. Executive Summary
4. Use of oxygen as key indicator for "before and after" trends
5. Availability of monitoring data in STORET
6. How representative is oxygen data used for "before and after" trends?
7. Statistical methods
8. Geographic representation of case study sites
9. Cost versus benefits analysis
10 . Editing for final report
Issue 1: Target Audience
Reviewers:
Linsky, Okun, Wolman, Hetling, Jobin, Isaacs, Parker, Billings , and Habibian
Comment summary:
Who is the audience for the report? How can the report provide useful information to policy makers,
legislators, regulatory agencies, and the general public? What is the overall message? How can the report be
structured to provide guidance for future water quality management programs? The report can be more than a
history; it can be an instrument for beneficial change. The report needs to clearly articulate the interrelat-
edness of the CWA and SDWA for water pollution control and water quality management in relation to both
public health (drinking water) and ecological quality of rivers and streams. The CWA and the secondary treatment
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
requirement have demonstrated some water quality success over 25 years. Future and continued successes for the
next 25 years, however, are not a given unless national policies are based on a sustainable strategy driven by citizen
stakeholder groups (Jobin). O&M costs are high and it is very important (but not politically highly visible) to main-
tain levels of funding as are replacement costs of obsolete POTWs. Jobin discusses three "traps" that have
hampered long-term sustainability of past water pollution control efforts. He points out the need to present
strong conclusions as well as recommendations to guide future efforts.
Response:
A discussion on the report audience has been included in Chapter 1 of the document. The primary
audience is the technical scientists and engineers who try to evaluate cause-effect relationships of pollutant
load and ambient water quality responses. The secondary audience is Congress, regulatory/policy profession-
als, and the informed public, who need to understand that a major public works program (the CWA Construc-
tion Grants and CWSRF programs) accomplished what it was designed to do—reduce BOD effluent loads from
municipal and industrial sources and improve dissolved oxygen in many previously degraded waterways of the
Nation. These same groups also need to understand that water pollution control efforts never end. The 1972 CWA
did not "solve" the problem; in fact, waste materials are generated continuously and effluent removal efficiencies
must increase in the future to compensate for population growth. Planning for O&M expenditures, as well as capital
expenditures for replacement of obsolete facilities and upgrades to maintain adequate levels/efficiency of wastewa-
ter removal is an ongoing requirement. Chapter 2 and the Executive Summary include a projection analysis that
demonstrates that many of the gains in national water quality improvements may be lost if future wastewater
infrastructure capacity does not keep pace with expected urban population growth.
Issue 2: Title of Final Report and Objectives of Study
Reviewers:
Landman, Hetling, Mearns, Kosco
Comment summary:
The title of the report, Progress in Water Quality: An Evaluation of the Benefits of the 1972 Clean
Water Act, is too broad and implies too large a scope of study (i.e., we address all issues of the CWA). The
title needs to be changed to be more representative of the data presented in the study. The authors need to
state more clearly up-front that the study was designed to evaluate the effectiveness of investments in POTW
upgrades on improving oxygen levels in previously degraded waterways and nothing more. The caveat for the
analysis is that POTW sources are only one component of many possible sources of oxygen-demanding loads
to waterways. It is important to get across the concept that improvements to POTWs alone are not sufficient
to restore and maintain water quality as a national goal. The study has demonstrated that upgrades to POTWs
had the expected result of improving oxygen levels in waterways once characterized by low levels. Can
changes in oxygen be isolated to the impact of POTW inputs alone? In this study the important contribution is
the findings of improvements in oxygen that are linked to POTW upgrades and investments—not the method-
ology.
Response:
The title has been changed to Progress in Water Quality: An Evaluation of the National Investment
in Municipal Wastewater Treatment. The objectives of the study are now clearly stated in Chapter 1 and the
Executive Summary. Also, Chapter 2 includes a section that compares POTW sources of BOD loading to
other major source categories (industrial point sources, CSOs, and urban and rural nonpoint sources) based on
EPA's NWPCAM. Statements have been added to stress that continued improvement in the Nation's water
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Appendix A: Summary of Peer Review Team Comments and Study Authors' Responses
quality conditions will require control of all major pollution sources, of which POTWs are only a portion.
(POTWs contribute about 21 percent of all point and nonpoint BOD sources nationwide.) In this document
both the findings and the data analysis methodology are given equal emphasis. A complete presentation of the
methodology allows the scientist or statistician to assess the level of rigor of the analysis, as well as demon-
strate the potential application of the methodology to other water pollution control performance measures.
Issue 3: Executive Summary
Reviewers:
Cook, Kirk, Landman, Dunn, Linsky, Brosnan, Kuhlman
Comment summary:
The Executive Summary is too long with too much defense of the methodology used for the analysis.
Most people, especially policy, regulatory, and general public, will read only the Executive Summary and not
care at all about (or understand) the technical details of how the analysis was performed. The key findings
need to be made very clear in a concise summary that in turn can be boiled down to a press release of a few
pages (which in turn can be boiled down to a "sound bite" and a "headline"). The Executive Summary needs a
discussion of the status of water quality nationwide in relation to all sources (synopsis of most recent national
water quality report to Congress?) The sequence of material presented in the Executive Summary should
follow the sequence presented in the main report. One suggestion is to publish only the Executive Summary
and put all the technical documentation of the main report on the EPA web site. The authors need to present
strong conclusions (Isaacs, Hetling) as well as solid recommendations (Hetling).
Response:
The Executive Summary has been entirely rewritten as a high-quality, "stand-alone" document that
presents the key findings of the study succinctly and in the same sequence as the main report. Also, the main
body of the report has been reorganized and streamlined and includes an introductory chapter (Chapter 1,
which is a road map to the rest of the report) as well as a summary and conclusions section at the end of each
chapter.
Issue 4: Use of Dissolved Oxygen as Key Water Quality Indicator for "Before and
After" Trends
Reviewers:
Hetling, Parker, Linsky, Jobin, Dunn, Smith, Jaworski
Comment summary:
Some reviewers, but not all, agreed that oxygen was most appropriate for questions posed for the study.
One reviewer suggested that dissolved oxygen saturation should have been used as the indicator rather than
dissolved oxygen concentration. The same reviewer also brought up a variety of statistical questions about
the approach and the validity of the techniques used for the analysis of dissolved oxygen trends. The review-
ers' consensus was that a more detailed rationale for the selection of dissolved oxygen as the key water
quality indicator used for the study was needed in the final report. The reviewers also recommended that a
better explanation of water quality standards for dissolved oxygen and the choice of 5 mg/L as a benchmark
concentration for comparison of "before and after" conditions be included in the final report. Some
reviewers suggested combining the discussion of factors affecting dissolved oxygen in rivers with the discus-
sion of pollutant loading.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Response:
Dissolved oxygen is a key chemical measure that has been used for many decades to characterize the
overall health of aquatic ecosystems. High concentrations (~5 mg/L) greater than about 60 percent saturation
levels are generally indicative of a healthy aquatic ecosystem whereas low concentrations (< 3 mg/L) less than
about 40 percent saturation may be indicative of a stressed ecosystem. A large historical database with
generally reliable measurements is available with records for a few waterways since the 1920s and 1930s.
There is a well-understood causal relationship between municipal and industrial wastewater loading of oxidiz-
able carbonaceous and nitrogenous materials (BOD), receiving waters' streamflow, and ambient concentra-
tions of dissolved oxygen. Excessive depletion of dissolved oxygen as a result of poorly treated wastewater
discharges was one of the major water pollution problems in many rivers and estuaries during the 1940s
through the 1960s. The technology of secondary treatment, required as a minimum technology for municipal
facilities by the 1972 CWA, is designed primarily to reduce the loading of BOD to improve dissolved oxygen
conditions in streams, rivers, and estuaries.
This issue is discussed in the Executive Summary and in Chapters 2 and 3 in the final report.
Issue 5: Availability of Monitoring Data in STORET
Reviewers:
Wolman, Hetling, Kirk, Lagnese
Comment summary:
The fact that the "before and after" trends analysis was based on an apparently limited data set of only
246 catalog units out of a total of 1,666 catalog units with reaches impacted by point source discharges
implies a significant problem with the availability and use of national-scale monitoring data from STORET
for "performance evaluations" of point and nonpoint source pollution control measures. The apparent lack of
a consistent and reliable water quality database on a national scale is a significant issue and needs to be
discussed in more detail in the final report. The reviewers asked if the final report could present recommen-
dations and conclusions about water quality monitoring programs that would provide guidance for future
policy decisions or analysis efforts.
Response:
National-scale assessments of "performance evaluations" of the impact of water pollution control
policies ideally should be based on a database large enough to provide a reliable sample of the effectiveness
of implementation of regulatory policy. The objective of the study was a quantitative assessment of how
much water quality has improved since the 1972 CWA. The purpose was to evaluate whether the national
investment of $61 billion (current year dollars) that was targeted toward upgrading municipal wastewater
treatment plants to secondary and better-than-secondary levels of treatment was, in fact, an effective regula-
tory policy for the Nation. As discussed under Issue 4, dissolved oxygen was selected as the key water
quality indicator for the evaluation. To characterize long-term trends in oxygen, data sets needed to be com-
piled to represent "before" conditions prior to the 1972 CWA for comparison to "after" conditions. Persistent
drought conditions were widespread in large areas of the northeast, middle Atlantic, and central United States
during both the early 1960s (1962-1966) and the late 1980s (1987-1988). Early in the study, 1961-1965 and
1986-1990 were selected as the 5-year blocks of time to represent "before and after" conditions. The choice
of 1961-1965 to represent conditions "before" the CWA was based, in part, on the availability of
national-scale dissolved oxygen data compiled from 1957-1965 by the FWQA (Gunnerson, 1965) from an early
monitoring program funded under the 1956 Amendments to the Federal Water Pollution Control Act.
After the "before and after" analysis was completed, an inventory of the availability of oxygen and other
water quality parameters in STORET from 1941-1995 was compiled. The limited availability of data for the
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Appendix A: Summary of Peer Review Team Comments and Study Authors' Responses
"before" period constrained the sample size of the data sets that could be compiled for the "before and after"
comparison. Nationwide, only 5,185 stations with 125,772 observations of oxygen were available for the
1961-1965 "before" period compared to 17,656 stations with 955,123 observations for the 1986-1990 "after"
years. The largest abundance of stations were monitored after passage of the 1972 CWA with 34,052 stations
and 749,125 observations recorded during 1971-1975. A considerably larger sample would most likely have
been available for the "before and after" trend analysis if the 5-year period of 1966-1970 (16,972 stations) or
1971-1975 (34,052 stations) had been selected as the "before" period rather then the period of much more
limited data availability, 1961-1965 (5,185 stations). Selection of 1961-1965 thus resulted in the analysis
being based on only about one-third of the data available in 1966-1970 and only about one-sixth of the data
available during the peak monitoring activity years of 1971-1975. Final selection of "before and after" data
sets is based on comparable "dry" hydrologic characteristics as a "filter" for the analysis.
Even with the limited data set available for the "before and after" analysis, the results clearly document
statistically significant improvements in dissolved oxygen with data sets aggregated over all spatial scales
from the relatively small RF1 reach to the catalog unit and the major river basin. The methodology can be
applied using 1966-1970 or 1971-1975 as the "before" period to enhance the robustness of the "before and
after" analysis for dissolved oxygen trends. The methodology can also be applied for other water quality
parameters for trend assessments of nutrients and TSS, for example, to evaluate the effectiveness of point and
nonpoint source control programs on these parameters.
Recommendations on monitoring programs:
• Sufficient federal funding to state and local government agencies should be made available for long
time periods (5- to 10-year programs) to ensure support for continuous operation of a national-scale
monitoring network and data collection efforts.
• Adequate federal funding must be made available to state and local governments to ensure the
continuation of state-local-federal data submission and data management activities, including ar-
chives of historical water quality data, with STORET designated as the centrally accessible data-
base for water quality data and information.
• State and local government agencies and university research groups receiving federal funds to
support water quality monitoring programs should be required to submit all data subjected to QA/
QC procedures in electronic format specified by EPA to STORET as the designated national
database repository for water quality data. All water quality data records submitted to STORET
should be required to be cross-referenced to geographic identifier codes defined for the Reach File
and the National Hydrography Database.
• Interagency coordination for joint sharing of water quality data and submission of data to STORET
should be established as standard operating procedure for all federal agencies involved in collecting
water quality data for monitoring, research, or other programmatic purposes in freshwater and
marine environments. Water quality data and information are collected by many federal agencies
other than EPA; USGS, NOAA, NPS, USDA, USAGE, U.S. Navy, and U.S. Coast Guard all collect
water quality data for a variety of geohydrologic, limnological, and oceanographic purposes. Comprehen-
sive national-scale assessments of the effectiveness of regulatory policies can be most successful only if
all available data are shared (subject to national security clearance constraints imposed by the
U.S. Navy) and pooled in a centrally accessible database designed to adhere to rigorous QA/QC proce-
dures.
• Adequate federal funding must be made available to ensure the development of state-of-the-art
software "tools" with up-to-date computer technology for the user community to be able to conduct
credible statistical analyses to evaluate the status and trends of key water quality parameters. Raw
data extracted from STORET and software "tools" should be made available on-line through EPA's
Office of Water web site.
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Issue 6: How Representative is Oxygen Data Used for "Before and After" Trends?
Reviewers:
Wolman, Hetling, Kirk, Lagnese, Parker, Lindstrom, Isaacs, Smith, Habibian
Comment summary:
Some reviewers thought that the "before and after" results were not particularly impressive as a basis to
proclaim national-scale improvements in dissolved oxygen. Other reviewers did, however, think the "before
and after" results were impressive and that the report presented solid evidence for documenting improvements
in oxygen that were undoubtedly significant. Some reviewers pointed out that NFS loads, even in reaches
impacted by point sources, probably confounded the analysis and contributed to "before and after" trends
where big improvements were not identified. Some reviewers suggested that the final report present data
showing (a) "before and after" oxygen trends for RF1 reaches impacted only by NFS under "dry" and "wet"
conditions; (b) "before and after" oxygen data for RF1 reaches showing the worst degradation using the point
source-impacted "dry" criteria; and (c) "before and after" BOD5 trends to correlate with the oxygen data. The
issues raised by the reviewers are twofold: (1) revise the report to present results to clearly document that
RF1 reaches with "before and after" improvements probably represent a significant portion of the US popula-
tion and municipal wastewater loads, and (2) show that the data filtering methodology for "dry" point source-
dominated reaches accurately represents the "worst-case" conditions response of ambient oxygen to changes
in waste loads.
Response:
Although the "before and after" evaluation of oxygen is based on data compiled from only 246 catalog
units and 311 RF1 reaches, the waterways included in the analysis accounted for about 62 million people
living in the 246 catalog units characterized by improvements in dissolved oxygen. The population repre-
sented in the "before and after" analysis thus accounts for about 31 percent of the total continental US
population of 197 million recorded in the 1990 census. During both the "before" and "after" periods, "dry"
hydrologic conditions (< 75 percent summer mean streamflow) were recorded in about 90 percent of all
catalog units for at least 1 of the 5 years of record with "dry" conditions persisting for an average of 2.5 years
during 1961-1965 and 2.7 years during 1986-1990. Filters used in the "before and after" analysis included
specification of hydrologic conditions as "dry,"" normal," or "wet" and selection of RF1 reaches defined by
the impact of nonpoint source and point source pollutant loads as "only PS impacted," "only NPS impacted,"
or "PS and NPS impacted." The results presented in the report emphasized the worst-case findings for "only
PS impacted" reaches under "dry" hydrologic conditions. The complete listing of the "before and after" data
for dissolved oxygen and BOD5 for the 246 catalog units with "before and after" data is presented in Appen-
dix D of this report. "Before and after" BOD5 data were correlated with "before and after" dissolved oxygen
data in the discussion of catalog unit and RF1 reach scale trends for the Upper White River catalog unit in
Indiana. The data tables identify the waterways ranked by the "before and after" change in oxygen and BOD5
from the greatest improvement to the worst degradation.
In response to a reviewer's suggestion, the "before and after" analysis was performed for RF1 reaches
impacted only by NPS loads under "dry" flow conditions. The results indicated that (a) very little "before and
after" data was available to characterize trends for reaches impacted only by NPS and (b) oxygen conditions
in NPS reaches were not characterized by the significant improvements identified for PS impacted reaches.
Selection of "dry" hydrologic conditions for at least 1 of 5 years for "only NPS impacted" reaches resulted in
extraction of a small sample of only 37 catalog units with sufficient "before and after" data sets. The greatest
improvement was characterized by oxygen increasing from 3.0 mg/L during 1961-1965 to 6.2 mg/L during
1986-1990 in the Lower Dan River watershed in North Carolina.
A-8
-------
Appendix A: Summary of Peer Review Team Comments and Study Authors' Responses
Issue 7: Statistical Methods
Reviewer:
Smith
Comment summary:
DO deficit data should be used instead of DO concentration data to account for possible differences in
temperature during the before and after periods. Discussions of the statistical effect of data aggregation should
be clarified, It should be stressed that pooling reach data at the national level enhances the ability to distinguish
signal from noise and obtain statistically significant results. More discussion is needed on uncertainty, particu-
larly where results are based on limited data. Some assessment should be made of the degree of statistical
dependence of DO concentration between reach-level results, to ensure there is no bias due to "clustering" of
monitoring stations in adjacent or nearby reaches.
Response:
Discussion has been added in Chapter 3 to address the selection of DO concentration over DO satura-
tion or DO deficit (see also Issue #4). The authors have adopted the wording "data aggregation" in conjunc-
tion with "spatial scale" in the description of the statistical methods and results. Discussion has also been
included in Chapter 3 to address uncertainty. Since the study authors found similar results in before versus
after DO concentration changes at all three data aggregation scales (i.e., two-thirds of hydrologic units at the
reach, catalog unit, and major river basin scales), additional analysis on spatial clustering of monitoring stations
was not performed.
Issue 8: Geographic Representation of Case Studies
Reviewers:
Lagnese, Parker, Kirk, Okun
Comment summary:
A few reviewers pointed out the lack of geographic diversity of case study sites. At least one case study
should have been selected to represent the western arid region. Other reviewers commented that the case
studies really presented a good documentation of improvements in water quality although how these were
related to the CWA was not always clearly explained.
Response:
The discussion on the study authors' logic for case study site selection has been expanded in Chapter 4.
Geographic diversity was not a priority in the selection process; instead, selection focused on heavily urban-
ized, highly populated waterways with a history of water quality problems related to municipal wastewater
treatment discharges. The case study chapters have been expanded to clarify the relationship of observed
water quality conditions to actions related to the CWA.
A-9
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Issue 9: Cost versus Benefit Analysis
Reviewers:
Lagnese, Parker, Linsky, Okun
Comment summary:
Not enough explanation is provided of how cost and benefit data were compiled for the three case
studies (Potomac, Upper Mississippi, and Willamette Rivers) presented in the Executive Summary and
Chapter 4 (overview of cases). A cost/benefit analysis is a major issue for the evaluation of the effectiveness
of the CWA. The cost/benefit data were, in fact, knowingly included in the Executive Summary without any
explanation at all.
Response:
The study authors agree that cos^enefit is a major issue for evaluation of the effectiveness of the
CWA. The original scope of this study was never intended to include cost versus benefit analysis of pollution
controls, but rather was to focus on national trends in population, wastewater treatment plant design capacity,
and water quality conditions in receiving waters. The cost versus benefit data provided for the three case
study sites was prepared under a separate study and does not extend to the other six case studies or nationally.
The study authors have chosen to remove the cost versus benefits data and information completely from the
document to avoid confusion or presentation of incomplete analyses since this is a national-scale study.
Issue 10: Editing for final report
Reviewers:
Wolman, Landman, Kirk
Comment summary:
Eliminate all self-congratulatory phrases claiming "success" or what a wonderful methodology and
study this is, etc. Edit out redundant material presented in several chapters. The tone of the report is "biased"
and "not objective." Provide a clear summery and conclusions sections where appropriate throughout the
document.
Response:
The document has been extensively revised and rewritten since the peer review. The study authors have
attempted to remove wherever possible any redundancy or biased statements. A summary and conclusions
section has been added at the end of each chapter. The entire study is based on factual information that speaks
for itself, allowing the readers to draw their own conclusions.
A-10
-------
Appendix B
National Municipal Wastewater
Inventory and Infrastructure,
1940 to 2016
Table Page
B-1 POTW facility inventory B-3
B-2 Resident population served by POTWs B-3
B-3 Wastewater flow B-3
B-4 Influent wastewater flow normalized to population served B-4
B-5 Influent CBOD5 load B-4
B-6 Effluent CBOD5 load B-4
B-7 CBOD5 removal efficiency B-5
B-8 Influent CBOD5 load normalized to population served B-5
B-9 Influent CBOD5 concentration B-5
B-10 Effluent CBOD5 concentration B-6
B-11 Influent CBODU load B-6
B-12 Effluent CBODU load B-6
B-13 CBODy removal efficiency B-7
B-14 Effluent CBODU concentration B-7
B-15 Influent NBOD load B-7
B-16 Effluent NBOD load B-8
B-17 NBOD removal efficiency B-8
B-18 Effluent NBOD concentration B-8
B-19 Influent BODU load B-9
B-20 Effluent BODy load B-9
B-21 Removal efficiency BODU B-9
B-22 Effluent BODU concentration B-10
B-23 Influent TSS load B-10
B-24 Effluent TSS load B-10
B-25 TSS removal efficiency B-11
B-26 Effluent TSS concentration B-11
B-27 Influent POC load B-11
B-28 Effluent POC load B-12
B-29 POC removal efficiency B-12
B-30 Effluent POC concentration B-12
B-31 Influent and effluent characteristics for CBOD5, CBOD^ TKN, andBODu B-13
B-32 Influent and effluent characteristics for TSS and POC B-15
B-33 Middle population projections of POTW loads of CBOD5, CBODy, NBOD and BODU, 1996-2050 B-16
B-1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table Page
B-34 Inventory of POTW facilities in 1972 in the United States B-17
B-35 Population served (millions) by POTW facilities in 1972 in the United States B-18
B-36 Data sources for trends in municipal wastewater treatment, 1940-2016 B-19
B-37 Municipal wastewater treatment categories presented in Appendix B tables B-20
Note: Values of -9.0 in the tables indicate that data was not available for the particular year and category of
waste treatment.
B-2
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table
Year
1940
1950
1962
1968
1972
19V3
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
B-1 . POTW facility inventory (Count)
No
Total
-9.0
11784.0
11698.0
14051.0
19355.0
-9.0
-9.0
-9.0
14850.0
15522.0
15662.0
15580.0
15541.0
15708.0
15613.0
16024.0
18303 0
Discharge
-9.0
0.0
0.0
0.0
142.0
-9.0
-9.0
-9.0
985.0
1361.0
1600.0
1726.0
1762.0
1854.0
1981.0
2032.0
2369.0
Raw
-9.0
5156.0
2262.0
1564.0
2265.0
1532.0
-9.0
-9.0
91.0
272.0
237.0
202.0
149.0
117.0
0.0
0.0
0.0
Primary
2938.0
3099.0
2717.0
2435.0
2530.0
2723.0
3032.0
-9.0
1306.0
1043.0
1036.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
64.0
-9.0
-9.0
-9.0
2972.0
2300.0
2083.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
2630.
3529.
6719.
10042.
13893.
16015.
16987.
2838.
6608.
7852.
7946.
8070.
8403.
8536.
9086.
9388.
9738
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Advanced
Secondary
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
2187.0
2443.0
2529.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
10.0
461.0
795.0
992.0
2719.0
701.0
251.0
231.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9 0
Less
than
Secondary
2938.0
3099.0
2717.0
2435.0
2594.0
-9.0
-9.0
2451.0
4278.0
3343.0
3119.0
2617.0
2112.0
1789.0
868.0
176.0
61 0
Greater
than
Secondary
0.0
0.0
0.0
10.0
461.0
-9.0
-9.0
-9.0
2888.0
2694.0
2760.0
2965.0
3115.0
3412.0
3678.0
4428.0
6135.0
B-2. Resident population served by POTWs
Total
70800000.0
91762001.0
118300000.0
140100000.0
141722242.0
-9.0
-9.0
-9.0
155227000.0
158337000.0
163525000.0
170643000.0
163319000.0
177536335.0
180614290.0
189710899.0
274722315.0
No
Discharge
0.0
0.0
0.0
0.0
825000.0
-9.0
-9.0
-9.0
2197000.0
3599000.0
4172000.0
5514000.0
5679000.0
6079611.0
7764363.0
7660876.0
14163722.0
B-3. Wastewater flow
Total
11682.0
15140.7
19519.5
23116.5
23384.2
-9.0
-9.0
-9.0
26799.5
25510.0
27202.7
27305.0
27956.8
29293 5
29801 4
31302.3
45329.2
No
Discharge
0.0
0.0
0.0
0.0
136.1
-9.0
-9.0
-9.0
362.5
438.3
490.9
600 0
608.0
1003.1
1281.1
1264.0
2337.0
Raw
32200000.0
35268437.0
14600000.0
10100000.0
4939928.0
3200000.0
-9.0
-9.0
3640000.0
2307000.0
1876000.0
1273000.0
1605000.0
1367172.0
0.0
0.0
0.0
Primary
18500000.0
24599743.0
42200000.0
44100000.0
50502813.0
54600000.0
-9.0
-9.0
18747000.0
19101714.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
1376059.0
-9.0
-9.0
-9.0
25333000.0
18214286.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
20100000.
31893821.
61500000.
85600000.
76270812.
105000000.
-9.
32523000.
56256000.
62680000.
67609000.
70656000.
72285000.
77954544
82907949.
81944349.
102321429
0
.0
0
0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
Advanced
Secondary
0.0
0.0
0.0
0.0
2257101.0
-9.0
-9.0
-9.0
30937000.0
47518000.0
50853000.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
300000.0
5550529.0
2700000.0
-9.0
45733000.0
18117000.0
4917000.0
5411000.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
18500000.0
24599743.0
42200000.0
44100000.0
51878872.0
-9.0
-9.0
40271000.0
44080000.0
37316000.0
33604000.0
33675000.0
28815000.0
26484096.0
21712715.0
17177492.0
5513147.0
Greater
than
Secondary
0.0
0.0
0.0
300000.0
7807630.0
-9.0
-9.0
-9.0
49054000.0
52435000.0
56264000.0
59525000.0
54935000.0
65650912.0
68229263.0
82928182.0
152724017.0
(million gallons per day)
Raw
5313.0
5819.3
2409.0
1666.5
815.1
528 0
-9.0
-9.0
600.6
380.7
309.5
210.0
264.8
225.6
0 0
0 0
0 0
Primary
3052.5
4059.0
6963.0
7276.5
8333.0
9009.0
-9.0
-9.0
3415.0
3035.4
2474.5
-9 0
-9.0
-9.0
-9 0
-9 0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
227.0
-9.0
-9.0
-9.0
3737.4
2895.1
2825.4
-9.0
-9.0
-9 0
-9.0
-9.0
-9.0
Secondary
3316.
5262
10147
14124
12584
17325
-9
5437
10138
9882
11009
11047
12140
12862
13679
13520
16883
.5
.5
.5
.0
.7
.0
.0
.5
.7
.1
.5
0
.0
.5
8
8
0
Advanced
Secondary
0.0
0.0
0.0
0.0
372.4
-9.0
-9.0
-9.0
4732.1
8654.9
9377.5
-9.0
-9 0
-9 0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
49.5
915.8
445.5
-9.0
7545.9
3813.2
751.6
714.7
-9 0
-9.0
-9.0
-9.0
-9 0
-9 0
Less
than
Secondary
3052.5
4059.0
6963.0
7276.5
8560.0
-9.0
-9.0
12653.6
7152.4
6157.1
5300.6
5335.0
4580.0
4369 9
3582.6
2834.3
909 7
Greater
than
Secondary
0.0
0.0
0.0
49.5
1288.3
-9.0
-9.0
7007.1
8545.3
8651.8
10092.2
10113 . 0
10364. 0
10832 4
11257 8
13683 . 1
25199 5
B-3
-------
Progress in Water Quality: An Evaluation of the National Investment in
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Municipal
Wastewater Treatment
B-4. Influent wastewater flow normalized to population served (gallons per person per day, default- 165)
Less Greater
Total
165.0
165.0
165.0
165.0
165.0
-9.0
-9.0
-9.0
172.6
161.1
166.4
160.0
171.2
165.0
165.0
165.0
165.0
No
Discharge
-9.0
-9.0
-9.0
-9.0
165 0
-9.0
-9.0
-9.0
165.0
121.8
117.7
108.8
107.1
165.0
165.0
165.0
165.0
B-5. Influent CBOD5
Total
9507.5
12322.5
15886.2
18813.6
19031.5
-9.0
-9.0
-9.0
21252.8
20528.9
21170.4
23395.3
23927.4
23840.8
24254.2
25475.7
36891.7
Kb
Discharge
0.0
0.0
0.0
0.0
110.8
-9.0
-9.0
-9.0
295.0
356.7
399.5
488.3
494.8
816.4
1042.7
1028.8
1902.0
B-6. Effluent CBOD5
Total
6343.7
7525.8
6882.9
6931.9
6767.9
-9.0
-9.0
-9.0
5509.8
5188.3
4379.9
3943.9
3923.5
4460.0
4033.7
3812.2
4024.9
No
Discharge
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Raw
165.0
165.0
165.0
165.0
165.0
165.0
-9.0
-9.0
165.0
165.0
165.0
165.0
165.0
165.0
-9.0
-9.0
-9.0
Primary
165.0
165.0
165.0
165.0
165.0
165.0
-9.0
-9.0
182.2
158.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
-9.0
-9.0
-9.0
-9.0
165.0
-9.0
-9.0
-9.0
147.5
158.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9 0
Secondary
165.0
165.0
165.0
165.0
165.0
165.0
-9.0
167.2
180.2
157.7
162.8
156.3
167.9
165.0
165.0
165.0
165.0
Advanced
Secondary
-9.0
-9.0
-9.0
-9.0
165.0
-9.0
-9.0
-9.0
153.0
182.1
184.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
-9.0
-9.0
-9.0
165.0
165.0
165.0
-9.0
165.0
210.5
152.9
132.1
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
than
Secondary
165.0
165.0
165.0
165.0
165.0
-9.0
-9.0
314.2
162.3
165.0
157.7
158.4
158.9
165.0
165.0
165.0
165.0
than
Secondary
-9.0
-9.0
-9.0
165.0
165.0
-9.0
-9.0
-9.0
174.2
165.0
179.4
169.9
188.7
165.0
165.0
165.0
165.0
load (metric tons per day)
Raw
4324.0
4736.1
1960.6
1356.3
663.4
429 7
-9.0
-9.0
488.8
309.8
251.9
170.9
215.5
183.6
0.0
0.0
0.0
Primary
2484 3
3303.4
5666.9
5922.1
6781.9
7332.1
-9.0
-9.0
2511.0
4700.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
184.8
-9.0
-9.0
-9.0
3210.0
2356.2
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
2699.2
4282.9
8258.7
11495.0
10242.2
14100.1
-9.0
3764.0
8222.0
7810.0
8623.0
9448.0
10378.0
10468.3
11133.5
11004.1
13740.4
Advanced
Secondary
0.0
0.0
0 0
0.0
303.1
-9.0
-9.0
-9.0
3419.0
6498.0
7030.0
-9 0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
40.3
745.4
362.6
-9.0
6141.4
3107.0
598.0
586.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
2484.3
3303.4
5666.9
5922.1
6966.7
-9.0
-9.0
10177.0
5721.0
5011.1
4280.0
4917.0
4325.0
3556.5
2915.7
2306.7
740.3
Greater
than
Secondary
0.0
0.0
0.0
40.3
1048.5
-9.0
-9.0
5392.0
6526.0
7041.3
7616.0
8371.0
8514.0
8816.1
9162.3
11136.2
20508.9
load (metric tons per day)
Raw
4324.0
4736.1
1960.6
1356.3
663.4
429.7
-9.0
-9.0
488.8
309.8
251.9
170.9
215.5
183.6
0.0
0.0
0.0
Primary
1614.8
2147.2
3683.5
3849.3
4408.2
4765.8
-9.0
-9.0
1487.0
2316.0
-9.0
-9 0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
92.4
-9.0
-9.0
-9.0
1167.0
1178.1
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
404.9
642.4
1238.8
1724.2
1536.3
2115.0
-9.0
518.0
1596.0
1469.0
1539.0
1135.0
1279.0
1570.2
1670.0
1650.6
2061.1
Advanced
Secondary
0.0
0.0
0.0
0.0
30.3
-9.0
-9.0
-9.0
362.0
752.0
582.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
2.0
37.3
18.1
-9.0
307.1
409.0
75.0
32.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
1614.8
2147.2
3683.5
3849.3
4500.6
-9.0
-9.0
4360.0
2654.0
2881.4
1975.0
2030.0
1834.0
2045.0
1676.5
1326.4
425.7
Greater
than
Secondary
0.0
0.0
0.0
2.0
67.6
-9.0
-9.0
324.0
771.0
528.1
614.0
608.0
595.0
661.2
687.2
835.2
1538.2
B-4
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-7.
Year
Default:
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table B-8.
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table B-9.
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
CBOD5
Total
33.3
38.9
56.7
63.2
64.4
-9.0
-9.0
-9.0
74.1
74.7
79.3
83.1
83.6
81.3
83.4
85.0
89.1
Influent
Total
0.296
0.296
0.296
0.296
0.296
-9.000
-9.000
-9.000
0.302
0.286
0.285
0.302
0.323
0.296
0.296
0.296
0.296
Influent
Total
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
-9.0
209.5
212.6
205.6
226.3
226.1
215.0
215.0
215.0
215.0
removal efficiency (Percent)
No
Discharge
100%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
100.0
-9.0
100.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
CBOD5
Kb
Discharge
-9.000
-9.000
-9.000
-9.000
0.296
-9.000
-9.000
-9.000
0.296
0.219
0.211
0.195
0.192
0.296
0.296
0.296
0.296
CBOD5
No
Discharge
-9.0
-9.0
-9.0
-9.0
215.0
-9.0
-9.0
-9.0
215.0
215.0
215 0
215.0
215.0
215.0
215.0
215.0
215.0
Raw
0%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
0.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Primary
35%
35.0
35.0
35.0
35.0
35.0
35.0
-9.0
-9.0
40.8
50.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
50%
-9.0
-9.0
-9.0
-9.0
50.0
-9.0
-9.0
-9.0
63 6
50.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
85%
85.0
85.0
85.0
85.0
85.0
85.0
-9.0
86.2
80.6
81.2
82.2
88.0
87.7
85.0
85.0
85.0
85.0
Advanced
Secondary
90%
-9.0
-9.0
-9.0
-9.0
90.0
-9.0
-9.0
-9.0
89.4
88.4
91.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
95%
-9.0
-9.0
-9.0
95.0
95.0
95.0
-9.0
95.0
86.8
87.5
94.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
42.5%
35.0
35.0
35.0
35.0
35.4
-9.0
-9.0
57.2
53.6
42.5
53.9
58.7
57.6
42.5
42.5
42.5
42.5
Greater
than
Secondary
92.5%
-9.0
-9.0
-9.0
95.0
93.6
-9.0
-9.0
94.0
88.2
92.5
91.9
92.7
93.0
92.5
92.5
92.5
92.5
load normalized to population served (Ibs CBODg per person per day, default = 0.296)
Raw
0.296
0.296
0.296
0.296
0.296
0.296
-9.000
-9.000
0.296
0.296
0.296
0.296
0.296
0.296
-9.000
-9.000
-9.000
concentration
Raw
215.0
215.0
215.0
215.0
215.0
215.0
-9 0
-9.0
215.0
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
-9.0
Primary
0.296
0.296
0.296
0.296
0.296
0.296
-9.000
-9.000
0.295
0.542
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
(mg/L,
Primary
215.0
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
194.2
409.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
-9.000
-9.000
-9.000
-9.000
0.296
-9.000
-9.000
-9.000
0.279
0.285
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
default =
Advanced
Primary
-9.0
-9.0
-9 0
-9.0
215.0
-9.0
-9.0
-9.0
226.9
215.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
0.296
0.296
0.296
0.296
0.296
0.296
-9.000
0.255
0.322
0.275
0.281
0.295
0.317
0.296
0.296
0.296
0.296
215.0 mg/L)
Secondary
215.0
215.0
215.0
215.0
215.0
215.0
-9.0
182.9
214.2
208.8
206.9
225.9
225.8
215.0
215.0
215.0
215.0
Advanced
Secondary
-9.000
-9.000
-9.000
-9.000
0.296
-9.000
-9.000
-9.000
0.244
0.301
0.305
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
Advanced
Secondary
-9.0
-9.0
-9.0
-9.0
215.0
-9.0
-9.0
-9.0
190.9
198.3
198.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
-9.000
-9.000
-9.000
0.296
0.296
0.296
-9.000
0.296
0.378
0.268
0.239
-9.000
-9.000
-9.000
-9.000
-9.000
-9.000
Advanced
Treatment
-9 0
-9.0
-9.0
215.0
215.0
215.0
-9.0
215.0
215.2
210.2
216.6
-9.0
-9.0
-9 0
-9.0
-9.0
-9.0
Less
than
Secondary
0.296
0.296
0.296
0.296
0.296
-9.000
-9.000
0.557
0.286
0.296
0.281
0.322
0.331
0.296
0.296
0.296
0.296
Less
than
Secondary
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
212.5
211.3
215.0
213.3
243.5
249.5
215.0
215.0
215.0
215.0
Greater
than
Secondary
-9.000
-9.000
-9.000
0.296
0 296
-9.000
-9.000
-9.000
0.293
0.296
0.298
0.310
0.342
0.296
0.296
0.296
0.296
Greater
than
Secondary
-9.0
-9.0
-9.0
215.0
215.0
-9.0
-9.0
203.3
201.7
215.0
199.4
218.7
217.0
215.0
215.0
215.0
215.0
B-5
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table B-10. Effluent CBOD5 concentration [mg/L]
Year
Total
Default;
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
143.5
131.3
93.2
79.2
76.5
-9.0
-9.0
-9.0
54.3
53.7
42.5
38.2
37.1
40.2
35.8
32.2
23.5
Kb
Discharge
0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
B-11. Influent CBODU
Total
11409.0
14786.9
19063.4
22576.3
22837.8
-9.0
-9.0
-9.0
25503.4
24634.7
25404.5
28074.3
28712.8
28609.0
29105.0
30570.9
44270.0
Kb
Discharge
0.0
0.0
0.0
0.0
132.9
-9.0
-9.0
-9.0
354.0
428.1
479.4
586.0
593.8
979.7
1251.2
1234.5
2282.4
B-12. Effluent CBODu
Total
8922.4
10943.4
11764.5
12689.4
12558.1
-9.0
-9.0
-9.0
11620.7
10685.4
9581.9
8439.7
8550.9
9869.3
9418.1
9232.0
10995.2
Kb
Discharge
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Raw Primary
215.0 139.75
215.0 139.8
215.0 139.8
215.0 139.8
215.0 139.8
215.0 139.8
215.0 139.8
-9.0 -9.0
-9.0 -9.0
215.0 115.0
215.0 201.6
215.0 -9.0
215.0 -9.0
215.0 -9.0
215.0 -9.0
-9.0 -9.0
-9.0 -9.0
-9.0 -9.0
Advanced
Primary
107.5
-9.0
-9.0
-9.0
-9.0
107.5
-9.0
-9.0
-9.0
82 5
107.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
32.25
32.3
32.3
32.3
32.3
32.3
32.3
-9.0
25.2
41.6
39.3
36.9
27.1
27.8
32.3
32.3
32.3
32.3
Advanced
Secondary
21.5
-9.0
-9.0
-9.0
-9.0
21.5
-9.0
-9.0
-9.0
20.2
23.0
16.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
10.75
-9.0
-9.0
-9.0
10.8
10.8
10.8
-9.0
10.8
28.3
26.4
11.8
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
123 . 63
139.8
139.8
139.8
139.8
138.9
-9.0
-9.0
91.0
98.0
123.6
98.4
100.5
105.8
123.6
123.6
123.6
123.6
Greater
than
Secondary
15.12
-9.0
-9.0
-9.0
10.8
13.9
-9.0
-9.0
12.2
23.8
16.1
16.1
15.9
15.2
16.1
16.1
16.1
16.1
load [metric tons per day]
Raw Primary
5188.9 2981.2
5683.3 3964.1
2352.7 6800.3
1627.6 7106.5
796.0 8138.2
515.7 8798.5
-9.0 -9.0
-9.0 -9.0
586.6 3013.2
371.8 5640.0
302.3 -9.0
205.1 -9.0
258.6 -9.0
220.3 -9.0
0.0 -9.0
0.0 -9.0
0.0 -9.0
Advanced
Primary
0.0
0.0
0.0
0.0
221.7
-9.0
-9.0
-9.0
3852.0
2827.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
3239.0
5139.5
9910.4
13794.0
12290.6
16920.2
-9.0
4516.8
9866.4
9372.0
10347.6
11337.6
12453.6
12561.9
13360.2
13204.9
16488.5
Advanced
Secondary
0.0
0.0
0.0
0.0
363.7
-9.0
-9.0
-9.0
4102.8
7797.6
8436.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
48.3
894.4
435.1
-9.0
7369.6
3728.4
717.6
703.2
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
2981.2
3964.1
6800.3
7106.5
8360.0
-9.0
-9.0
12212.4
6865.2
6013.3
5136.0
5900.4
5190.0
4267.8
3498.9
2768.1
888.4
Greater
than
Secondary
0.0
0.0
0.0
48.3
1258.2
-9.0
-9.0
6470.4
7831.2
8449.6
9139.2
10045.2
10216.8
10579.3
10994.8
13363.4
24610.6
load [metric tons per day]
Raw Primary
5188.9 2583.7
5683.3 3435.6
2352.7 5893.6
1627.6 6158.9
796.0 7053.1
515.7 7625.4
-9.0 -9.0
-9.0 -9.0
586.6 2379.2
371.8 3705.6
302.3 -9.0
205.1 -9.0
258.6 -9.0
220.3 -9.0
0.0 -9.0
0.0 -9.0
0.0 -9.0
Advanced
Primary
0.0
0.0
0.0
0.0
147.8
-9.0
-9.0
-9.0
1867.2
1885.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
1149.8
1824.5
3518.2
4896.9
4363.2
6006.7
-9.0
1471.1
4532.6
4172.0
4370.8
3223.4
3632.4
4459.5
4742.9
4687.7
5853.4
Advanced
Secondary
0.0
0.0
0.0
0.0
86.1
-9.0
-9.0
-9.0
1028.1
2135.7
1652.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
6.0
111.8
54.4
-9.0
921.2
1227.0
225.0
96.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
2583.7
3435.6
5893.6
6158.9
7201.0
-9.0
-9.0
6976.0
4246.4
4610.2
3160.0
3248.0
2934.4
3272.0
2682.5
2122.2
681.1
Greater
than
Secondary
0.0
0.0
0.0
6.0
197.9
-9.0
-9.0
939.6
2255.1
1531.5
1748.9
1763.2
1725.5
1917.5
1992.8
2422.1
4460.7
B-6
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-13. CBODU removal efficiency [Percent]
Year
Defaul t
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
Defaul t
Default
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Total
21.8
26.0
38.3
43.8
45.0
-9.0
-9.0
-9.0
54.4
56.6
62.3
69.9
70.2
65.5
67.6
69.8
75.2
No
Discharge
100%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
100.0
-9.0
100.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
B-14. Effluent CBOD
Total
CBOD0:CBOD
201.8
190.9
159.2
145.0
141.9
-9.0
-9.0
-9.0
114.5
110.7
93.1
81.7
80.8
89.0
83.5
77.9
64.1
1*5
Discharge
0.0
0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
o.o
B-15. Influent NBOD
Total
6123.3
7936.3
10231.5
12116.9
12257.2
-9.0
-9.0
-9.0
14047.4
13371.5
14258.8
14312.4
14654.1
15354.7
15620.9
16407.7
23760.1
No
Discharge
0.0
0.0
0.0
0.0
71.4
-9.0
-9.0
-9.0
190.0
229.7
257.3
314.5
318.7
525.8
671.5
662.6
1225.0
Raw
0%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
0.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Primary
13.3%
13.3
13.3
13.3
13.3
13.3
13.3
-9.0
-9.0
21.0
34.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
33.3%
-9.0
-9.0
-9.0
-9.0
33.3
-9.0
-9.0
-9.0
51.5
33.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
64.5%
64.5
64.5
64.5
64.5
64.5
64.5
-9.0
67.4
54.1
55.5
57.8
71.6
70.8
64.5
64.5
64.5
64.5
u concentration [mg/L; CBODU - BODS A
Raw
1.2
258.0
258.0
258.0
258.0
258.0
258.0
258.0
-9.0
-9.0
258.0
258.0
258.0
258.0
258.0
258.0
-9.0
-9.0
-9.0
load [metric
Raw
2784.9
3050.3
1262.7
873.5
427.2
276.8
-9.0
-9.0
314.8
199.5
162.3
110.1
138.8
118.2
0.0
0.0
0.0
Primary
1.6
223 . 60
223.6
223.6
223.6
223.6
223.6
223.6
-9.0
-9.0
184.0
322.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
1.6
172.0
-9.0
-9.0
-9.0
-9.0
172.0
-9.0
-9.0
-9.0
132.0
172.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
2.84
91.59
91.6
91.6
91.6
91.6
91.6
91.6
-9.0
71.5
118.1
111.5
104.9
77.1
79.0
91.6
91.6
91.6
91.6
Advanced
Secondary
76.3%
-9.0
-9.0
-9.0
-9.0
76.3
-9.0
-9.0
-9.0
74.9
72.6
80.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
87.5*
-9.0
-9.0
-9.0
87.5
87.5
87.5
-9.0
87.5
67.1
68.6
86.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
23.3%
13.3
13.3
13.3
13.3
13.9
-9.0
-9.0
42.9
38.1
23.3
38.5
45.0
43.5
23.3
23.3
23.3
23.3
Greater
than
Secondary
81.9%
-9.0
-9.0
-9.0
87.5
84.3
-9.0
-9.0
85.5
71.2
81.9
80.9
82.4
83.1
81.9
81.9
81.9
81.9
'.(CBODjBOD,)]
Advanced
Secondary
2.84
61.06
-9.0
-9.0
-9.0
-9.0
61.1
-9.0
-9.0
-9.0
57.4
65.2
46.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
3.0
32.25
-9.0
-9.0
-9.0
32.3
32.3
32.3
-9.0
32.3
85.0
79.1
35.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
1.6
197.80
223.6
223.6
223.6
223.6
222.2
-9.0
-9.0
145.6
156.8
197.8
157.5
160.8
169.3
197.8
197.8
197.8
197.8
Greater
than
Secondary
2.9
46.76
-9.0
-9.0
-9.0
32.3
40.6
-9.0
-9.0
35.4
69.7
46. 8
45.8
46.1
44.0
46.8
46.8
46.8
46.8
tons per day; NBOD = 4.57 x TKN]
Primary
1600.0
2127.6
3649.8
3814.1
4367.9
4722.2
-9.0
-9.0
1790.1
1591.1
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
119.0
-9.0
-9.0
-9.0
1959.0
1517.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
1738.4
2758.4
5319.0
7403.4
6596.5
9081.2
-9.0
2850.2
5314.4
5179.9
5770.8
5790.5
6363.4
6742.1
7170.5
7087.2
8849.5
Advanced
Secondary
0.0
0.0
0.0
0.0
195.2
-9.0
-9.0
-9.0
2480.4
4536.6
4915.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
25.9
480.1
233.5
-9.0
3955.3
1998.8
394.0
374.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
1600.0
2127.6
3649.8
3814.1
4486.9
-9.0
-9.0
6632.6
3749.1
3227.4
2778.4
2796.4
2400.7
2290.5
1877.9
1485.6
476.8
Greater
than
Secondary
0.0
0.0
0.0
25.9
675.3
-9.0
-9.0
-9.0
4479.2
4535.0
5290.0
5300.9
5432.5
5678.0
5901.0
7172.3
13208.8
B-7
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
TableB-16. Effluent NBOD
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
TableB-17
Year
Default:
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table B-18
Year
Defaul t :
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Total
5145.5
6475.2
7513.7
8591.1
8273.3
-9.0
-9.0
-9.0
7525.8
6916.3
7167.8
7030.9
7143.3
7327.0
7204.6
7093.2
8611.3
No
Discharge
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
. NBOD removal
Total
16.0
18.4
26.6
29.1
32.5
-9.0
-9.0
-9.0
46.4
48.3
49.7
50.9
51.3
52.3
53.9
56.8
63.8
No
Discharge
100%
-9.0
-9 0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
100.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
. Effluent NBOD
Total
116.4
113.0
101.7
98.2
93.5
-9.0
-9.0
-9.0
74.2
71.6
69.6
68.0
67.5
66.1
63.9
59.9
50.2
No
Discharge
0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
load [metric tons per day; NBOD = 4.57 x TKN]
Raw
2784.9
3050.3
1262.7
873.5
427.2
276.8
-9.0
-9.0
314.8
199.5
162.3
110.1
138.8
118.2
0.0
0.0
0.0
Primary
1248.0
1659.5
2846.8
2975.0
3406.9
3683.3
-9.0
-9.0
1396.2
1241.0
-9.0
-9 0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
92.8
-9.0
-9.0
-9.0
1528.0
1183.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
1112.6
1765.4
3404.2
4738.1
4221.8
5812.0
-9.0
1824.1
3401.2
3315.1
3693.3
3705.9
4072.6
4315.0
4589.1
4535.8
5663.7
Advanced
Secondary
0.0
0.0
0.0
0.0
42.9
-9.0
-9.0
-9.0
545.7
998.1
1081.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
4.4
81.6
39.7
-9.0
672.4
339.8
67.0
63.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
1248.0
1659.5
2846.8
2975.0
3499.8
-9.0
-9.0
5173.4
2924.3
2517.4
2167.2
2181.2
1872.5
1786.6
1464.7
1158.8
371.9
Greater
than
Secondary
0.0
0.0
0.0
4.4
124.6
-9.0
-9.0
-9.0
885.5
884.3
1145.1
1033.7
1059.3
1107.2
1150.7
1398.6
2575.7
efficiency [Percent]
Raw
0%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Primary
22%
22.0
22.0
22.0
22.0
22.0
22.0
-9.0
-9.0
22.0
22.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
concentration [mg/L;
Raw
138.47
138.5
138.5
138.5
138.5
138.5
138.5
-9 0
-9.0
138.5
138.5
138.5
138 5
138.5
138.5
-9.0
-9.0
-9.0
Primary
10S.O
108.0
108.0
108.0
108.0
108.0
108.0
-9.0
-9.0
108.0
108.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
22%
-9.0
-9.0
-9.0
-9.0
22.0
-9.0
-9.0
-9.0
2.2.0
22.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
NBOD =
Advanced
Primary
108.0
-9.0
-9.0
-9.0
-9.0
108 0
-9.0
-9.0
-9.0
108.0
108.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
36%
36.0
36.0
36.0
36 0
36.0
36.0
-9.0
36.0
36.0
36.0
36.0
36.0
36.0
36.0
36.0
36.0
36.0
Advanced
Secondary
78%
-9.0
-9.0
-9.0
-9.0
78.0
-9.0
-9.0
-9.0
78.0
78.0
78.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
83%
-9.0
-9.0
-9.0
83.0
83.0
83.0
-9.0
83.0
83.0
83.0
83.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
22%
22.0
22.0
22.0
22.0
22.0
-9.0
-9.0
22.0
22.0
22.0
22.0
22.0
22.0
22.0
22.0
22.0
22.0
Greater
than
Secondary
80. 5%
-9.0
-9.0
-9.0
83.0
81.6
-9.0
-9.0
-9.0
80.2
80.5
78.4
80.5
80.5
80.5
80.5
80.5
80.5
4.57 x TKN]
Secondary
88. 62
88.6
88.6
88.6
88.6
88.6
88.6
-9.0
88.6
88.6
88.6
88.6
88.6
88.6
88.6
88.6
88.6
88.6
Advanced
Secondary
30.46
-9.0
-9.0
-9.0
-9.0
30.5
-9.0
-9.0
-9.0
30.5
30.5
30.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
23.54
-9.0
-9.0
-9.0
23.5
23.5
23.5
-9.0
23.5
23.5
23.5
23.5
-9 0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
108.0
108.0
108.0
108.0
108.0
108.0
-9.0
-9.0
108.0
108.0
108.0
108.0
108.0
108.0
108.0
108.0
108.0
108.0
Greater
than
Secondary
27.0
-9.0
-9.0
-9.0
23.5
25.5
-9.0
-9.0
-0.3
27.4
27.0
30.0
27.0
27.0
27.0
27.0
27.0
27.0
B-8
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-19. Influent BODU load [metric tons per day; BODU = CBODU + NBOD]
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
Default
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Total
17532.4
22723.2
29294.9
34693.3
35095.0
-9.0
-9.0
-9.0
39550.8
38006.2
39663.3
42386.8
43366.9
43963.7
44725.9
46978.5
68030.1
No
Discharge
0.0
0.0
0.0
0.0
204.3
-9.0
-9.0
-9.0
544.0
657.8
736.7
900.5
912.5
1505.5
1922.7
1897.1
3507.4
B-20. Effluent BODy
Total
14067.9
17418.6
19278.2
21280.5
20831.4
-9.0
-9.0
-9.0
19146.5
17601.7
16749.8
15470.6
15694.2
17196.3
16622.7
16325.2
19606.6
No
Discharge
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Raw
7973.8
8733.6
3615.4
2501.1
1223.3
792.4
-9.0
-9.0
901.4
571.3
464.6
315.2
397.4
338.6
0.0
0.0
0.0
Primary
4581.2
6091.7
10450.1
10920.6
12506.1
13520.7
-9.0
-9.0
4803.3
7231.1
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
340.8
-9.0
-9.0
-9.0
5811.0
4345.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
4977.4
7897.9
15229.4
21197.3
18887.1
26001.4
-9.0
7367.0
15180.8
14551.9
16118.4
17128.1
18817.0
19304.1
20530.7
20292.1
25338.1
load [metric tons per day; BODU = CBOD
Raw
7973.8
8733.6
3615.4
2501.1
1223.3
792.4
-9.0
-9.0
901.4
571.3
464.6
315.2
397.4
338.6
0.0
0.0
0.0
B-21 . Removal efficiency BODy
Total
19.8
23.3
34.2
38.7
40.6
-9.0
-9.0
-9.0
51.6
53.7
57.8
63.5
63.8
60.9
62.8
65.2
71.2
fto
Discharge
100%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Raw
0%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Primary
3831.7
5095.1
8740.4
9133.9
10460.1
11308.7
-9.0
-9.0
3775.4
4946.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
[Percent]
Primary
16.4%
16.4
16.4
16.4
16.4
16.4
16.4
-9.0
-9.0
21.4
31.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
240.7
-9.0
-9.0
-9.0
3395.2
3068.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
29.4%
-9.0
-9.0
-9.0
-9.0
29.4
-9.0
-9.0
-9.0
41.6
29.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
2262.4
3589.9
6922.3
9635.0
8584.9
11818.6
-9.0
3295.2
7933.8
7487.1
8064.1
6929.3
7704.9
8774.4
9332.0
9223.5
11517.1
Secondary
54.5%
54.5
54.5
54.5
54.5
54.5
54.5
-9.0
55.3
47.7
48.5
50.0
59.5
59.1
54.5
54.5
54.5
54.5
Advanced
Secondary
0.0
0.0
0.0
0.0
558.9
-9.0
-9.0
-9.0
6583.2
12334.2
13351.4
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
74.3
1374.5
668.6
-9.0
11325.0
5727.2
1111.6
1077.8
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
4581.2
6091.7
10450.1
10920.6
12846.9
-9.0
-9.0
18845.0
10614.3
9240.6
7914.4
8696.8
7590.7
6558.3
5376.8
4253.7
1365.2
Greater
than
Secondary
0.0
0.0
0.0
74.3
1933.4
-9.0
-9.0
-9.0
12310.4
12984.6
14429.2
15346.1
15649.3
16257.3
16895.8
20535.7
37819.4
u + NBOD]
Advanced
Secondary
0.0
0.0
0.0
0.0
129.0
-9.0
-9.0
-9.0
1573.8
3133.7
2734.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Secondary
76.9%
-9.0
-9.0
-9.0
-9.0
76.9
-9.0
-9.0
-9.0
76.1
74.6
79.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
10.5
193.4
94.1
-9.0
1593.6
1566.8
292.0
159.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
85.9%
-9.0
-9.0
-9.0
85.9
85.9
85.9
-9.0
85.9
72.6
73.7
85.2
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
3831.7
5095.1
8740.4
9133.9
10700.8
-9.0
-9.0
12149.4
7170.7
7127.5
5327.2
5429.2
4806.9
5058.6
4147.2
3281.0
1053.0
Less
than
Secondary
22.9%
16.4
16.4
16.4
16.4
16.7
-9.0
-9.0
35.5
32.4
22.9
32.7
37.6
36.7
22.9
22.9
22.9
22.9
Greater
than
Secondary
0.0
0.0
0.0
10.5
322.4
-9.0
-9.0
-9.0
3140 6
2415.8
2893.9
2796.9
2784.8
3024.7
3143.5
3820.7
7036.4
Greater
than
Secondary
81.4%
-9.0
-9.0
-9.0
85.9
83.3
-9.0
-9.0
-9.0
74.5
81.4
79.9
81.8
82.2
81.4
81.4
81.4
81.4
B-9
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table
Year
B-22. Effluent BODU concentration [mg/L;
Total
Defaul t :
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
318.1
303.9
260.9
243.2
235.3
-9.0
-9.0
-9.0
188.7
182.3
162.7
149.7
148.3
155.1
147.4
137.8
114.3
No
Discharge
0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
B-23. Influent TSS load
Total
9507.5
12322.5
15886.2
18813.6
19031.5
-9.0
-9.0
-9.0
21811.1
20761.6
22139.2
22222.5
22753.0
23840.8
24254.2
25475.7
36891.7
No
Discharge
0.0
0.0
0.0
0.0
110.8
-9.0
-9 0
-9.0
295.0
356.7
399.5
488.3
494.8
816.4
1042.7
1028.8
1902.0
B-24. Effluent TSS load
Total
5782.1
6730.4
5454.7
5237.7
4953.1
-9.0
-9.0
-9.0
3628.7
3133.7
2934.9
2832.7
2707.8
2664.0
2286.0
2081.4
1908.1
tfo
Discharge
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Raw Primary
396.5 331.6
396.5 331.6
396.5 331.6
396.5 331.6
396.5 331.6
396.5 331.6
396.5 331.6
-9.0 -9.0
-9.0 -9.0
396.5 292.1
396.5 430.5
396.5 -9.0
396.5 -9.0
396.5 -9.0
396.5 -9.0
-9.0 -9.0
-9.0 -9.0
-9.0 -9.0
BODU = CBODU + NBOD]
Advanced
Primary
280.0
-9.0
-9.0
-9.0
-9.0
280.0
-9.0
-9.0
-9.0
240.0
280.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
180.2
180.2
180.2
180.2
180.2
180.2
180.2
-9.0
160.1
206.7
200.1
193.5
165.7
167 7
180.2
180.2
180.2
180.2
Advanced
Secondary
91.5
-9.0
-9.0
-9.0
-9.0
91.5
-9.0
-9.0
-9.0
87.9
95.7
77.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
55.8
-9.0
-9.0
-9.0
55.8
55.8
55.8
-9.0
55.8
108.5
102.6
59.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
305.8
331.6
331.6
331.6
331.6
330.2
-9.0
-9.0
253.6
264.8
305.8
265.5
268.8
277.3
305.8
305.8
305.8
305.8
Greater
than
Secondary
73. 8
-9 0
-9.0
-9.0
55.8
66.1
-9.0
-9.0
-0.3
97.1
73.8
75.8
73.1
71.0
73.8
73.8
73.8
73.8
[metric tons per day]
Raw Primary
4324.0 2484.3
4736.1 3303.4
1960.6 5666.9
1356.3 5922.1
663.4 6781.9
429.7 7332.1
-9.0 -9.0
-9.0 -9.0
488.8 2779.4
309.8 2470.4
251.9 -9.0
170.9 -9.0
215.5 -9.0
183.6 -9.0
0.0 -9.0
0.0 -9 0
0.0 -9.0
Advanced
Primary
0.0
0.0
0.0
0.0
184.8
-9.0
-9.0
-9.0
3041.7
2356.2
-9.0
-9.0
-9.0
-9 0
-9.0
-9.0
-9.0
Secondary
2699.2
4282.9
8258.7
11495.0
10242.2
14100.1
-9.0
4425.4
8251.5
8042.7
8960.2
8990.7
9880.3
10468.3
11133.5
11004.1
13740.4
Advanced
Secondary
0.0
0 0
0.0
0.0
303.1
-9.0
-9.0
-9.0
3851.3
7043.9
7632.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
40.3
745.4
362.6
-9.0
6141.4
3103.4
611.7
581.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
2484.3
3303.4
5666.9
5922.1
6966.7
-9.0
-9.0
10298.3
5821.1
5011.1
4314.0
4341.9
3727.5
3556.5
2915.7
2306.7
740.3
Greater
than
Secondary
0.0
0.0
0.0
40.3
1048.5
-9.0
-9.0
-9.0
6954.7
7041.3
8213.6
8230.6
8434.9
8816.1
9162.3
11136.2
20508.9
[metric tons per day]
Raw Primary
4324.0 1242.2
4736.1 1651.7
1960.6 2833.5
1356.3 2961.0
663.4 3390.9
429.7 3666.0
-9.0 -9.0
-9.0 -9.0
488 8 1389.7
309.8 1235.2
251.9 -9.0
170.9 -9.0
215.5 -9.0
183.6 -9.0
0.0 -9.0
0.0 -9.0
0.0 -9.0
Advanced
Primary
0.0
0.0
0.0
0.0
55.4
-9.0
-9.0
-9.0
912.5
706.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
215.9
342.6
660.7
919.6
819.4
1128.0
-9.0
354.0
660.1
643.4
716.8
719.3
790.4
837.5
890.7
880.3
1099.2
Advanced
Secondary
0.0
0 0
0.0
0.0
9.1
-9.0
-9.0
-9.0
115.5
211.3
229.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
0.8
14.9
7.3
-9.0
122.8
62.1
12.2
11.6
-9.0
-9.0
-9.0
-9 0
-9.0
-9.0
Less
than
Secondary
1242.2
1651.7
2833.5
2961.0
3446.4
-9.0
-9.0
4119.3
2302.2
2004.4
1725.6
1736.8
1491.0
1422.6
1166.3
922.7
296.1
Greater
than
Secondary
0.0
0.0
0.0
0.8
24.0
-9.0
-9.0
-9.0
177.6
176 0
240.6
205.8
210.9
220.4
229.1
278.4
512.7
B-10
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table
Year
B-25. TSS
Total
Defaul t :
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
39.2
45.4
65.7
72.2
74.0
-9.0
-9.0
-9.0
83.4
84.9
86.7
87.3
88.1
88.8
90.6
91.8
94.8
removal efficiency [Percent]
No
Discharge
100%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
100.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Raw
0%
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Primary
50%
50.0
50.0
50.0
50.0
50.0
50.0
-9.0
-9.0
50.0
50.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
B-26. Effluent TSS concentration [mg/L;
Total
Default;
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table
Year
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
130.8
117.4
73.8
59.9
56.0
-9.0
-9.0
-9.0
35.8
32.5
28.5
27.4
25.6
24.0
20.3
17.6
11.1
No
Discharge
0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
B-27. Influent POC load
Total
3137.5
4066.4
5242.4
6208.5
6280.4
-9.0
-9.0
-9.0
7197.6
6851.3
7305.9
7333.4
7508.5
7867.5
8003.9
8407.0
12174.2
No
Discharge
0.0
0.0
0.0
0.0
36.6
-9.0
-9.0
-9.0
97.4
117.7
131.8
161.1
163.3
269.4
344.1
339.5
627.7
Raw
215.0
215.0
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
215.0
215.0
215.0
215.0
215.0
215.0
-9.0
-9.0
-9.0
[metric
Raw
1426.9
1562.9
647.0
447.6
218.9
141.8
-9.0
-9.0
161.3
102.2
83.1
56.4
71.1
60.6
0.0
0.0
0.0
Primary
107.5
107.5
107.5
107.5
107.5
107.5
107.5
-9.0
-9.0
107.5
107.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
70%
-9.0
-9.0
-9.0
-9.0
70.0
-9.0
-9.0
-9.0
70.0
70.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
92%
92.0
92.0
92.0
92.0
92.0
92.0
-9.0
92.0
92.0
92.0
92.0
92.0
92.0
92.0
92.0
92.0
92.0
default Influent TSS
Advanced
Primary
64.5
-9.0
-9.0
-9.0
-9.0
64.5
-9.0
-9.0
-9.0
64.5
64.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
tons per day; POC
Primary
819.8
1090.1
1870.1
1954.3
2238.0
2419.6
-9.0
-9.0
917.2
815.2
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
61.0
-9.0
-9.0
-9.0
1003.8
777.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
17.2
17.2
17.2
17.2
17.2
17.2
17.2
-9.0
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
17.2
Advanced
Secondary
97%
-9.0
-9.0
-9.0
-9.0
97.0
-9.0
-9.0
-9.0
97.0
97.0
97.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
98%
-9.0
-9.0
-9.0
98.0
98.0
98.0
-9.0
98.0
98.0
98.0
98.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
60%
50.0
50.0
50.0
50.0
50.5
-9.0
-9.0
60.0
60.5
60.0
60.0
60.0
60.0
60.0
60.0
60.0
-60.0
Greater
than
Secondary
57.5%
-9.0
-9.0
-9.0
98.0
97.7
-9.0
-9.0
-9.0
97.4
97.5
97.1
97.5
97.5
97.5
97.5
97.5
97.5
= 21 5.0 mg/L]
Advanced
Secondary
6.45
-9.0
-9.0
-9.0
-9.0
6.5
-9.0
-9.0
-9.0
6.5
6.5
6.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
= TSS x (POM:TSS)
Secondary
890.7
1413.4
2725.4
3793.3
3379.9
4653.0
-9.0
1460.4
2723.0
2654.1
2956.9
2966.9
3260.5
3454.5
3674.0
3631.3
4534.3
Advanced
Secondary
0.0
0.0
0.0
0.0
100.0
-9.0
-9.0
-9.0
1270.9
2324.5
2518.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
4.3
-9.0
-9.0
-9.0
4.3
4.3
4.3
-9.0
4.3
4.3
4.3
4.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
x (C:DW)]
Advanced
Treatment
0.0
0.0
0.0
13.3
246.0
119.6
-9.0
2026.6
1024.1
201.9
191.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
86.0
107.5
107.5
107.5
107.5
106.4
-9.0
-9.0
86.0
85.0
86.0
86.0
86.0
86.0
86.0
86.0
86.0
86.0
Less
than
Secondary
819.8
1090.1
1870.1
1954.3
2299.0
-9.0
-9.0
3398.4
1921.0
1653.6
1423.6
1432.8
1230.1
1173.6
962 2
761.2
244.3
Greater
than
Secondary
5.38
-9.0
-9.0
-9.0
4.3
4.9
-9.0
-9.0
-0.3
5.5
5.4
6.3
5.4
5.4
5.4
5.4
5.4
5.4
Greater
than
Secondary
0.0
0.0
0.0
13.3
346.0
-9.0
-9.0
-9.0
2295.0
2323.6
2710.5
2716.1
2783.5
2909.3
3023.6
3674.9
6767.9
B-11
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table B-28. Effluent POC load [metric tons per day; POC = TSS x (POM:TSS) x (C:DW)]
Year
1940
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table B-29
Year
Default:
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
Table B-30
Total
3137.5
1944.0
2266.9
1876.1
1799.8
1724.5
-9.0
-9.0
-9.0
1244.1
1069.0
994.5
955.5
902.8
883.6
747.4
668.1
564.3
. POC
Total
38.0
44.3
64.2
71.0
72.5
-9.0
-9.0
-9.0
82.7
84.4
86.4
87.0
88.0
88.8
90.7
92.1
95.4
No
Discharge Raw
0.0
0.0
0.0
0.0
0.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
removal
No
Discharge
100*
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
100.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
. Effluent POC
1426
1426
1562
647
447
218
141
-9
-9
161
102
83
56
71
60
0
0
0
.9
.9
.9
.0
.6
.9
.8
.0
.0
.3
.2
.1
.4
.1
.6
.0
.0
.0
Primary
819.8
453.4
602.9
1034.2
1080.8
1237.7
1338.1
-9.0
-9.0
507.2
450.8
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
0.0
0.0
0.0
0.0
0.0
20.2
-9.0
-9.0
-9.0
333.1
258 0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
890.7
63.7
101.1
194.9
271.3
241.7
332.8
-9.0
104.4
194.7
189.8
211.5
212.2
233.2
247.1
262.7
259.7
324.3
Advanced
Secondary
0.0
0.0
0.0
0.0
0.0
2.7
-9.0
-9.0
-9.0
34.1
62.3
67.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.0
0.0
0.0
0.0
0.2
3.3
1.6
-9.0
27.0
13.7
2.7
2.6
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
819.8
453.4
602.9
1034.2
1080.8
1257.9
-9.0
-9.0
1503.5
840.3
731.6
629.8
633.9
544.2
519.2
425.7
336.8
108.1
Greater
than
Secondary
0.0
0.0
0.0
0.0
0.2
6.0
-9.0
-9.0
-9.0
47.7
45.3
70.1
53.0
54.3
56.7
59.0
71.7
132.0
efficiency [Percent]
Raw
-9
-9
-9
-9
-9
-9
-9
-9
-9
-9
0
-9
-9
-9
-9
-9
-9
0%
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
concentration
Primary
44.7%
44.7
44.7
44.7
44.7
44 7
44.7
-9.0
-9.0
44.7
44.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Primary
66.8%
-9.0
-9.0
-9.0
-9.0
66.8
-9.0
-9.0
-9.0
66.8
66.8
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
92.8%
92.8
92.8
92.8
92.8
92.8
92.8
-9.0
92.8
92.8
92.8
92.8
92.8
92.8
92.8
92.8
92.8
92.8
Advanced
Secondary
97.3%
-9.0
-9.0
-9.0
-9.0
97.3
-9.0
-9.0
-9.0
97.3
97.3
97.3
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
58.7*
-9.0
-9.0
-9.0
98.7
98.7
98.7
-9.0
98.7
98.7
98.7
98.7
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
55.8*
44.7
44.7
44.7
44.7
45.3
-9.0
-9.0
55.8
56.3
55.8
55.8
55.8
55.8
55.8
55.8
55.8
55.8
Greater
than
Secondary
98.0%
-9.0
-9.0
-9.0
98.7
98.3
-9.0
-9.0
-9.0
97.9
98.0
97.4
98.0
98.0
98.0
98.0
98.0
98.0
[mg/L; POC = TSS x (POM:TSS) x (C:DW);
default effluent POC = 70.95 mg/L;
Year
Total
No
Discharge
Default POM: TSS (mg/mg) 0.00
Default Effluent POC
1940
1950
1962
1968
1972
1973
1974
1976
1978
1980
1982
1984
1986
1988
1992
1996
2016
44.0
39.6
25.4
20.6
19.5
-9.0
-9.0
-9.0
12.3
11.1
9.7
9.2
8.5
8.0
6.6
5.6
3.3
(mg/L) 0.0
-9.0
-9.0
-9.0
-9.0
0.0
-9.0
-9.0
-9.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
Raw
0.
75
70.95
71
71
71
71
71
71
-9
-9
71
71
71
71
71
71
-9
-9
-9
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
.0
Primary
0.83
39.24
39.2
39.2
39.2
39.2
39.2
39.2
-9.0
-9.0
39.2
39.2
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
C:DW=0.44 mg C/mg DW]
Advanced
Primary
0.83
23.54
-9.0
-9.0
-9.0
-9.0
23.5
-9.0
-9.0
-9.0
23.5
23.5
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Secondary
0.67
5.07
5.1
5.1
5.1
5.1
5.1
5.1
-9.0
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
Advanced
Secondary
0,67
1.90
-9.0
-9.0
-9.0
-9.0
1.9
-9.0
-9.0
-9.0
1.9
1.9
1.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Advanced
Treatment
0.50
0.95
-9.0
-9.0
-9.0
0.9
0.9
0.9
-9.0
0.9
0.9
0.9
0.9
-9.0
-9.0
-9.0
-9.0
-9.0
-9.0
Less
than
Secondary
0.83
31.39
39.2
39.2
39.2
39.2
38.8
-9.0
-9.0
31.4
31.0
31.4
31.4
31.4
31.4
31.4
31.4
31.4
31.4
Greater
than
Secondary
0.585
1.38
-9.0
-9.0
-9.0
0.9
1.2
-9.0
-9.0
-0.3
1.5
1.4
1.8
1.4
1.4
1.4
1.4
1.4
1.4
B-12
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-31. Influent and effluent characteristics for CBOD5, CBODU, TKN, and BODy
5-day Carbonaceous BOD (CBOD )
Type Category
1. No Discharge
2 . Raw
3 . Primary
4 . Advanced Primary
5 . Secondary
6 . Advanced Secondary
7 . Advanced Treatment
8. Secondary (No. 6 + No. 7)
Ultimate Carbonaceous BOD (CBODu)
Type Category
1. No Discharge
2. Raw
3 . Primary
4 . Advanced Primary
5 . Secondary
6 . Advanced Secondary
7 . Advanced Treatment
8. Secondary (No. 6 + No . 7 )
Influent
mg/L
215.00
215.00
215.00
215.00
215.00
215.00
215.00
215.00
215.00
Effluent
mg/L
0.00
215.00
139.75
107.50
32.25
21.50
10.75
123.63
16.12
Removal
Percent
100.0
0.0
35.0
50.0
85.0
90.0
95.0
42.5
92.5
Conversion
Factor
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
Conversion Factor =CBODU:BODS ratios
Influent
mg/L
258.00
258.00
258.00
258.00
258. 00
258.00
258.00
258. 00
258.00
Effluent
mg/L
0.00
258.00
223.60
172.00
91.59
61.06
32.25
197.80
46.76
Removal
Percent
100.0
0.0
13.3
33.3
64.5
76.3
87.5
23.3
81.9
Conversion
Factor
1.000
1.200
1.600
1.600
2.840
2.840
3.000
1.600
2.900
Total Kjedhal Nitrogen (TKN) Organic-N + NH3-N
Type Category
1. No Discharge
2. Raw
3 . Primary
4 . Advanced Primary
5 . Secondary
6 . Advanced Secondary
7 . Advanced Treatment
8. Secondary (No. 6 + No. 7)
Influent
mg/L
0.30
30.30
30.30
30.30
30.30
30.30
30.30
30.30
30.30
Effluent
mg/L
0.00
30.30
23.63
23.63
19.39
6.67
5.15
23.63
5.91
Removal
Percent
100.0
0.0
22.0
22.0
36.0
78.0
83.0
22.0
80.5
Conversion
Fact
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
B-13
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Nitrogenous BOD NBOD = 4.57x TKN Conversion
Type Category
1. No Discharge
2 . Raw
3 . Primary
4 . Advanced Primary
5 . Secondary
6 . Advanced Secondary
7 . Advanced Treatment
8. Secondary (No. 6 +
Ultimate BOD (BOD} CBODu
Type Category
1. No Discharge
2 . Raw
3 . Primary
4 . Advanced Primary
5 . Secondary
6 . Advanced Secondary
7 . Advanced Treatment
8. Secondary (No. 6 +
Influent
mg/L
138.47
138.47
138.47
138.47
138.47
138.47
138.47
No. 4) 138.47
No. 7) 138.47
+ NBOD
Influent
mg/L
396.47
396.47
396.47
396.47
396.47
396.47
396.47
No. 4) 396.47
No. 7) 396.47
factor = 4. 75 mg
Effluent
mg/L
0.00
138.47
108.01
108.01
88.62
30.46
23.54
108.01
27.00
Effluent
mg/L
0.00
396.47
331.61
280.01
180.21
91.52
55.79
305.81
73.76
O2pergN
Removal
Percent
100.0
0.0
22.0
22.0
36.0
78.0
83.0
22.0
80.5
Removal
Percent
100.0
0.0
16.4
29.4
54.5
76.9
85.9
22.9
81.4
Conversion
Factor
4.570
4.570
4.570
4.570
4.570
4.570
4.570
4.570
4.570
Conversion
Factor
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
B-14
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-32. Influent and effluent characteristics for TSS and POC
Total Suspended Solids (TSS) TSS - Volatile SS + Non-volatile SS (fixed) = Organic SS + Inorganic SS
Influent
Type Category mg/L
1.
2.
3.
4.
5.
6.
7.
8.
9.
No Discharge
Raw
Primary
Advanced Primary
Secondary
Advanced Secondary
Advanced Treatment
Secondary (No. 6 + No . 7 )
215.
215.
215.
215.
215.
215.
215.
215.
215.
00
00
00
00
00
00
00
00
00
Effluent
mg/L
0
215
107
64
17
6
4
86
5
.00
.00
.50
.50
.20
.45
.30
.00
.38
Removal Conversion
Percent Fact
100.
0.
50.
70.
92.
97.
98.
60.
97.
0
0
0
0
0
0
0
0
5
1
1
1
1
1
1
1
1
1
.000
.000
.000
.000
.000
.000
.000
.000
.000
Paniculate Organic Carbon (POC)
POC = TSS x [(POM:TSS) x C:DW)]
POM:TSS = fraction of Particulate Organic Matter (Volatile SS:TSS)
C:DW = Carbon: Dry Weight = 0.44 mg C per mg DW
Conversion Factor = (POM:TSS) x (C:DW)
Type Category POM:
1.
2.
3.
4.
5.
6.
7.
8.
9,
No Discharge
Raw
Primary
Advanced Primary
Secondary
Advanced Secondary
Advanced Treatment
Secondary (No . 6 + No . 7 )
0
0
0
0
0
0
0
0
0
TSS
.00
.75
.83
.83
.67
.67
.50
.83
.58
Influent Effluent
mg / L mg / L
70
70
70
70
70
70
70
70
70
.95
.95
.95
.95
.95
.95
.95
.95
.95
0
70
39
23
5
1
0
31
1
.00
.95
.24
.54
.07
.90
.95
.39
.38
Removal Conversion
Percent Factor
100
0
44
66
92
97
98
55
98
.0
.0
.7
.8
.8
.3
.7
.8
.0
0
0
0
0
0
0
0
0
0
.330
.330
.365
.365
.295
.295
.220
.365
.257
B-15
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table B-33. Middle population projections of POTW loads of CBOD5, CBODU, NBOD and BOD^ 1996-2050
Population
Served
Year
1940
1950
1962
1968
1972
1978
1982
1988
1992
1996
1991
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
Population
132164569
151325798
NA
NA
NA
219555000
230075000
227258220
246928467
NA
267645000
270002000
272330000
274634000
276918000
279189000
281452000
283713000
285981000
288269000
290583000
292928000
295306000
297716000
300157000
302624000
305112000
307617000
310134000
312658000
315185000
317711000
320231000
322742000
325239000
327720000
330183000
332626000
335050000
337454000
339839000
342208000
344560000
346899000
349227000
351544000
353853000
356157000
358457000
360756000
363056000
365358000
367666000
369980000
372303000
374636000
376981000
379339000
381713000
384106000
386522000
388962000
391431000
393931000
Percent
53.
60.
70.
71.
78.
73.
72.
73.
74.
75.
75.
76.
77.
78
79.
80
80
81.
82
83.
84
84
,5%
6%
NA
NA
NA
.7%
7%
.1%
,1%
NA
.6%
,4%
,3%
, 1%
,9%
,7%
,5%
.4%
.2%
.0%
8%
.6%
.5%
,3%
.1%
.9%
85.7%
86
87.
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
88
.6%
.4%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
Effluent
CBOD5
mt/day -,
6344
7526
6883
6932
6768
5510
4380
4460
4034
3812
3853
3877
3899
3919
3938
3954
3970
3983
3996
4006
4016
4025
4032
4037
4042
4045
4046
4046
4044
4040
4073
4106
4138
4171
4203
4235
4267
4298
4330
4361
4391
4422
4452
4483
4513
4543
4573
4602
4632
4662
4691
4721
4751
4781
4811
4841
4871
4902
4933
4964
4995
5026
5058
5090
Load Effluent
CBOL\ CBODu
^ Removal
33.
38.
56.
63.
64.
74.
79.
81.
83.
85.
85.
85.
85.
85.
86.
86.
86.
86.
86.
87.
87.
87.
87.
87.
88.
88.
88.
88.
88.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
89.
3%
9%
7%
2%
4%
1%
3%
3%
4%
0%
2%
4%
6%
8%
0%
3%
5%
7%
9%
1%
3%
5%
7%
9%
1%
3%
5%
7%
9%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
mt/day !
8922
10943
11765
12689
12558
11621
9582
9869
9418
9232
9375
9478
9579
9678
9774
9868
9960
10050
10139
10226
10313
10398
10482
10566
10648
10730
10809
10887
10963
11037
11126
11215
11304
11393
11481
11569
11656
11742
11827
11912
11996
12080
12163
12246
12328
12410
12491
12573
12654
12735
12816
12897
12979
13060
13142
13225
13308
13391
13475
13559
13644
13731
13818
13906
Load
CBODu
fc Removal
21.
26.
38.
43.
45.
54.
62.
65.
67.
69.
70.
70.
70.
70.
71.
71.
71.
71.
72.
72.
72.
73.
73.
73.
73.
74.
74.
74.
74.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75.
75
75.
75.
75.
75.
75.
75.
75.
75
75.
75
75
75.
75
75
75
75
75
8%
0%
3%
8%
0%
4%
3%
5%
6%
8%
1%
3%
6%
9%
1%
4%
7%
9%
2%
5%
8%
0%
3%
6%
8%
1%
4%
6%
9%
2%
2%
2%
2%
2%
2%
.2%
2%
2%
2%
2%
.2%
2%
.2%
.2%
2%
.2%
2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
.2%
Effluent
NBOD
mt/day «
5146
6475
7514
8591
8273
7526
7168
7327
7205
7093
7208
7294
7378
7460
7541
7620
7698
7775
7851
7926
8000
8074
8148
8221
8294
8366
8437
8507
8576
8644
8714
8784
8853
8923
8992
9060
9129
9196
9263
9330
9396
9461
9526
9591
9655
9719
9783
9847
9910
9974
10037
10101
10165
10229
10293
10358
10422
10488
10553
10619
10686
10754
10822
10891
Load
NBOD
; Removal
16.0%
18.4%
26.6%
29.1%
32.5%
46.4%
49.7%
52.3%
53.9%
56.8%
57.1%
57.5%
57.8%
58.2%
58.5%
58.9%
59.2%
59.6%
59 9%
60.3%
60.6%
61.0%
61.3%
61.7%
62.0%
62.4%
62.7%
63.1%
63.4%
63.8%
63.8%
63.8%
63.8%
63.8%
63 8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63 8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
63.8%
Effluent
BODu
mt/day ?
14068
17419
19278
21281
20831
19147
16750
17196
16623
16325
16583
16772
16957
17138
17315
17489
17658
17825
17990
18152
18313
18472
18631
18787
18942
19096
19247
19395
19540
19681
19840
19999
20158
20316
20473
20629
20784
20938
21090
21242
21392
21541
21689
21836
21983
22129
22274
22419
22564
22709
22853
22998
23144
23289
23435
23582
23730
23878
24028
24178
24331
24484
24640
24797
Load
BODu
i Removal
19.8%
23.3%
34.2%
38.7%
40.6%
51.6%
57.8%
60.9%
62.8%
65.2%
65.5%
65.8%
66.1%
66.4%
66.7%
67.0%
67.3%
67.6%
67.9%
68.2%
68.5%
68.8%
69.1%
69.4%
69.7%
70.0%
70.3%
70.6%
70.9%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
71.2%
B-16
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-34. Inventory of POTW facilities in 1972 in the United States (USEPA, 1972)
Flow Range (MGD)
Facility Type
None (Raw)
Minor
Primary
Settling tank (no details)
Septic tank
Imhoff tanks
Mechanical cleaned tanks474
Plain, hop-bottom tanks48
Unknown
Intermediate
Secondary
Other
Activated sludge
Extended aeration
High rate trickling filter
Standard rate trickling filter
Intermediate sand filter
Land application
Oxidation pond
Unknown filter
Unknown
Tertiary
Unknown category
0-1
141
17
1523
92
252
624
264
3
33
18
10839
547
1151
1568
1231
1414
483
70
3638
249
488
373
18
1-5
9
4
312
16
3
19
59
0
7
21
1220
19
306
44
417
201
4
6
115
37
71
44
21
5-10
0
3
60
0
0
1
1
0
0
4
172
4
80
4
37
22
1
1
6
7
10
6
4
10-25
0
0
1
0
0
0
60
3
0
0
2
0
1
1
0
0
0
0
0
0
0
1
0
>25
4
0
76
6
1
2
40
2
4
14
156
3
82
4
36
8
0
0
3
2
18
5
14
Unknown
2111
20
558
17
394
36
898
56
69
7
1646
285
123
102
77
93
77
65
705
39
80
32
7
Total
2265
44
2530
131
650
682
113
64
14035
858
1743
1723
1798
1738
565
142
4467
334
667
461
64
TOTAL
12911
1610
245
255
4374
19399
B-17
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table B-35. Population served (millions) by POTW facilities in 1972 in the United States (USEPA, 1972)
Flow Range (MGD)
Facility Type
None (Raw)
Minor
Primary
Settling tank (no details)
Septic tank
Imhoff tanks
Mechanical cleaned tanks
Plain, hop-bottom tanks
Unknown
Intermediate
Secondary
Other
Activated sludge
Extended aeration
High rate trickling filter
Standard rate trickling filter
Intermediate sand filter
Land application
Oxidation pond
Unknown filter
Unknown
Tertiary
Unknown category
TOTAL
0-1
0.
0.
3.
0.
0.
1.
1.
0.
0.
0.
22.
0.
4.
1.
4.
4,
0.
0.
4.
0.
1.
0,
0
26.
,2
,1
5
.2
.2
1
.7
,2
.1
.1
.0
.3
,1
.4
,9
.4
.3
.1
.7
.6
.2
.5
.1
.4
1
0
0
5
0
0
0
4
0
0
0
19
0
5
0
7
2
0
0
1
0
1
0
0
26
-5
.2
.1
.4
.3
.1
.2
.5
.2
.1
.4
.2
.2
.4
.5
.0
.9
.1
.1
.3
.7
.0
.7
.4
.0
5-10
0.
0.
2.
0.
0.
0.
2.
0.
0.
0.
8.
0.
4.
0.
1.
1.
0.
0.
0.
0.
0.
0.
0.
11.
0
2
6
0
0
0
6
0
0
2
6
1
0
6
7
0
1
1
2
3
5
2
2
8
10-25
0
0
0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
0
0
0
0
0
0
1
.0
.0
.2
.0
.0
.0
.2
.0
.0
.0
.4
.0
.3
.1
.0
.0
.0
.0
.0
.0
.0
.2
.0
.8
>25 Unknown
1.
0.
21.
1.
0.
0.
16.
1.
2.
5.
46.
0.
29.
0.
4.
0.
0.
0.
0.
2.
7.
1.
5.
75.
8
0
8
0
4
5
1
8
0
1
.1
.2
.1
4
.8
.7
.0
0
.3
,8
.8
.1
.1
.9
3.
0.
12.
0.
0.
0.
4.
0,
6.
0.
5.
1,
0.
0,
1.
0.
0,
0.
0.
0
0.
0
0
21
.1
.7
,4
,6
.4
.1
.7
.0
,6
.1
.0
.4
.4
.1
.2
.3
.1
.2
.8
.1
.4
.1
.1
.4
Total
5
1
45
2
1
1
29
2
8
5
102
2
43
4
19
9
0
0
7
4
10
2
5
163
.3
.1
.9
.1
.1
.9
.8
.2
.8
.9
.3
.2
.3
.1
.6
.3
.6
.5
.3
.5
.9
.8
.9
.3
B-18
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Table B-36. Data sources for trends in municipal wastewater treatment, 1940-2016
1940 Population served data from FWPCA (1970). Inventory of municipal wastewater facilities from NCWQ (1976).
Data not available for no-discharge category; assumed zero for calculation of totals.
1950 Population served data and inventory of municipal wastewater facilities from USPHS (1951). Data not available
for no-discharge category; assumed zero for calculation of totals.
1962 Population served data and inventory of municipal wastewater facilities from USEPA(1974). Data not available
for no-discharge category; assumed zero for calculation of totals.
1968 Population served data and inventory of municipal wastewater facilities from USEPA (1974) and USDOI (1970).
Data not available for no-discharge category; assumed zero for calculation of totals.
1972 Population served data from ASIWPCA( 1984). Inventory of municipal wastewater facilities from EPA (1972).
Significant differences in population served data between USEPA (1972) (102.3 million) and ASIWPCA (1984)
(76.3 million) for secondary treatment. USEPA (1972) includes population served by oxidation ponds (7.5
million, 4467 facilities) and land application (0.5 million, 142 facilities) in the total population served of 102.3
million for "secondary" treatment. ASIWPCA (1984) reports 76.2 million served by secondary with no break-
down of categories of facilities given. To be consistent with trends in population served by secondary plants
reported for 1968 (85.6 million) and 1978 (56.3 million), the population served data from ASIWPCA (1984) is
used to estimate wastewater flow, influent and effluent loading of BOD5 for 1972.
1973 Population served data and inventory of municipal wastewater facilities from USEPA (1974). Data not available
for no-discharge category; assumed zero for calculation of totals.
1974 Inventory of municipal wastewater facilities from NCWQ (1976). Population served data not available for any
category.
1976 Population served data and inventory of municipal wastewater facilities from USEPA (1976). Data not available
for raw population served and effluent flow. Data not available for no-discharge category; assumed zero for
calculation of totals.
1978 Population served data, inventory of municipal wastewater facilities, wastewater effluent flow (as 1000 m3/
day), influent and effluent BOD loading data from USEPA (1978). Effluent flow from USEPA (1978) converted
from 1000 mVday to mgd using conversion factor of 0.2642. Population served by raw discharge reported as
364,000 persons in Table 10 of the EPA (1978) Needs Survey. To be consistent with trends in population served
by raw discharge for data reported for 1968 (10.1 million), 1972 (4.9 million), 1980 (2.3 million) and 1982 (1.9
million), the value for 1978 given in Table 10 appears to be in error by factor of 10. The population served by
raw discharge for 1978 is increased by a factor of 10 to 3.64 million for this study. Data reported in USEPA
(1978) for effluent flow, influent and effluent BOD loading for raw discharge, computed from erroneous
population served data, is not used. The number of facilities reported in USEPA (1978) as raw discharge
systems (n=91) is not consistent with trend of 2,265 raw facilities reported for 1972 and 237 raw facilities
reported for 1982. There is a possible factor of 10 error in Needs Survey data table since n=910 raw facilities
would be consistent with the decreasing trend in the number of raw facilities from 1972 to 1982.
1980 Population served data, inventory of municipal wastewater facilities, wastewater effluent flow (as 1000 m3/
day), influent and effluent BOD loading data and percent BOD removal from USEPA (1980). Effluent flow from
5 5
USEPA (1980) converted from 1000 mVday to mgd by conversion factor of 0.2642. Data not available for raw
effluent flow.
B- 19
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
1982 Population served data, inventory of municipal wastewater facilities, wastewater effluent flow (as 1000 m3/
day), influent and effluent BOD loading data, and percent BOD removal from USEPA( 1982). Effluent flow
5 5
from USEPA(1982) converted from 1000 mVday to mgd by conversion factor of 0.2642. Data not available for
raw effluent flow.
1984 Population served data, inventory of municipal wastewater facilities, wastewater effluent flow (as mgd),
influent and effluent BOD loading data, and percent BOD removal from USEPA (1984). Data not available for
5 5
raw effluent flow.
1986 Population served data, inventory of municipal wastewater facilities, wastewater effluent flow (as mgd),
influent and effluent BOD loading data, and percent BOD removal from USEPA (1986). Data not available for
5 5
raw effluent flow.
1988 Population served data and inventory of municipal wastewater facilities from USEPA (1989).
1992 Population served data and inventory of municipal wastewater facilities from USEPA (1993).
1996 Population served data and inventory of municipal wastewater facilities from USEPA (1997).
2016 Projection of population served and inventory of municipal wastewater facilities for the year 2016 from USEPA
(1997).
Table B-37. Municipal wastewater treatment categories presented in Appendix B tables
Total Sum of all treatment categories
No Discharge Municipal wastewater treatment facilities that do not discharge effluent to surface waters;
most no-discharge facilities are oxidation or stabilization ponds designed for evaporation and
or infiltration; no discharge also includes facilities designed for recycling and reuse or spray
irrigation systems.
Raw Collection system only; no treatment provided; effluent = influent
Primary Primary treatment
Advanced Primary Advanced primary treatment
Secondary Greater than secondary is the sum of advanced secondary + advanced treatment
B-20
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Data Sources
The primary data sources for the analysis of POTW wastewater trends included the municipal wastewater inventories
published by the USPHS from 1940 through 1968 (USPHS, 1951; NCWQ, 1976; USEPA, 1974) and USEPA' s Clean Water
Needs Surveys (CWNS) conducted from 1973 through 1996 (USEPA, 1976,1978,1980,1982,1984,1986,1989,1993,1997).
Each data source reported the number of municipal wastewater treatment plants and the population served by raw,
primary, advanced primary, secondary, advanced secondary and advanced treatment levels of wastewater treatment.
Where data was available to differentiate primary from advanced primary and advanced secondary from advanced
treatment, the data was added to define "less than secondary" and "greater than secondary" categories. For some of the
USEPA Needs Surveys, facility inventories and population served data was compiled as "less than secondary" and
"better than secondary"; data was not available to differentiate primary and advanced primary or advanced secondary
and advanced treatment levels of wastewater treatment. The USEPA Clean Water Needs Surveys also compiled effluent
flow, influent and effluent loading, and percent removal of BOD in the reports for 1978,1980,1982,1984,and 1986. For
the years in which this data was not available, wastewater effluent flow, influent and effluent BOD5, CBODu, TKN, NBOD,
BODu, TSS, and POC loading data was estimated based on (a) population served; (b) constant normalized flow rate of 165
gallons per capita per day (gpcd); (c) influent BOD5 of 215 mg/L and effluent BOD5 removal efficiencies; (d) effluent ratios
of CBODu: BOD5; (e) influent TKN of 30.3 mg/L and effluent TKN removal efficiencies; (f) influent TSS of 215 mg/L and
effluent TSS removal efficiencies; and (g) effluent ratios of the particulate organic fraction of TSS and a constant ratio of
carbon:dry weight (C:DW).
Constant Per Capita Flow Rate
The constant per capita flow rate of 165 gpcd is based on the mean (n=5) of the total population served and total waste-
water flow data compiled in the USEPA Clean Water Needs Surveys for 1978 through 1986 (see Table B-4). The rate of
per capita flow, ranging from 160 to 173 gpcd, includes residential (55 percent), commercial and industrial (20 percent),
stormwater (4 percent) and infiltration and inflow (20 percent) components of wastewater flow (see AMSA, 1997). The
constant per capita flow rate of 165 gpcd used in this study to estimate trends of municipal wastewater flow and loading is
identical to the typical United States average (165 gpcd) within the wide range (65-290 gpcd) of municipal water use that
accounts for residential, commercial and industrial, and public water uses in the United States (see Metcalf and Eddy,
1991). Public wastewater flow, obviously related to public water withdrawals, can range from 70 to 130 percent of the rate
of water withdrawal with a reasonable assumption being that wastewater flow is approximately equal to withdrawals by
water supplies (Steel, 1960).
Influent BOD.
D
The influent BOD5 concentration of 215 mg/L, consistent with many other estimates of raw wastewater strength (e.g.,
AMSA, 1997; Tetra Tech, 1999; Metcalf and Eddy, 1991), is based on the mean (n=5) nationally aggregated ratio of the
total influent BOD5 loading rate normalized to total wastewater flow reported in the USEPA Clean Water Needs Surveys
for 1978 through 1986 (see Table B-9). The influent concentration, ranging from 209 to 229 mg/L for these years, includes
the residential, commercial and industrial and infiltration and inflow contributions to the total influent BOD5 load to
municipal wastewater treatment plants. Using the influent BOD5 concentration of 215 mg/L and the normalized flow rate of
165 gpcd, the normalized influent BOD5 loading rate (0.296 Ib BOD5 per person per day) accounts for the nationally
aggregated mixture of domestic, commercial and industrial and infiltration and inflow components of wastewater. The
loading rate used in this analysis is almost a factor of two greater than the typical textbook value for the "population
equivalent" (PE) of 1 PE = 0.17 Ib BOD5 per person per day. Typical textbook values account for only the average per
capita residential load contributed by combined stormwater and domestic wastewater; the industrial and commercial
component is not included (Fair et al., 1971).
B-21
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Effluent BOD,
The effluent BOD5 loading rates, estimated using removal efficiencies typically assigned for NPDES permit limits and
wastewater treatment plant design assumptions, are based on an influent concentration of 215 mg/L and removal efficien-
cies (as percentage) assigned to each level of treatment. The BOD5 removal efficiencies assumed for primary (35 percent),
advanced primary (50 percent), and less than secondary (42.5 percent), although somewhat lower than removal efficien-
cies reported for primary (41 percent), advanced primary (64 percent), and less than secondary (54-57 percent) based on
PCS data compiled for the USEPA Clean Water Needs Surveys for 1976, 1978, and 1982, are consistent with typical
textbook values reported for BOD5 removal efficiency for primary treatment plants (see Metcalf and Eddy, 1991).
The BOD5 removal efficiencies assumed for secondary (85 percent), advanced secondary (90 percent), advanced waste
treatment (95 percent), and better than secondary (92.5 percent) are comparable to removal efficiencies for secondary (82-
86 percent), advanced secondary (89-92 percent), advanced waste treatment (87-94 percent), and better than secondary
(94 percent) based on PCS data compiled in the Clean Water Needs Surveys for 1976,1978, and 1982. The removal
efficiencies for secondary, advanced secondary and advanced waste treatment used in this study, consistent with
textbook design values, are based on an influent concentration of 215 mg/L and the ranges of removal efficiencies and
effluent concentrations of BOD5 used to define these treatment categories in the USEPA Clean Water Needs Survey for
1978 (USEPA, 1978).
Secondary treatment was defined in the 1978 Needs Survey by a BOD5 effluent concentration of 30 mg/L with the removal
efficiency ranging from 84 to 89 percent (USEPA, 1978). Advanced secondary was defined by an effluent BOD5 range of
10-30 mg/L, and advanced waste treatment was defined by an effluent BOD5 concentration less than, or equal to, 10 mg/L
(USEPA, 1978). Assuming a mean influent concentration of 215 mg/L, a mid-range effluent concentration of 20 mg/L for
advanced secondary, and 10 mg/L for advanced waste treatment, BOD5 removal efficiencies were assigned as 90 percent
for advanced secondary and 95 percent for advanced waste treatment.
Ultimate BOD
Influent and effluent loading rates of the ultimate carbonaceous BOD (CBODu) were estimated from the BOD5 loads and
conversion ratios of ultimate to 5-day BOD (CBODu:CBOD5) defined for each level of municipal treatment (Leo et al., 1984;
Thomann and Mueller, 1987). Since it is impossible to determine whether historical BOD effluent loads included the
5
suppression of nitrification (see Hall and Foxen, 1984), it is assumed that BOD5 is approximately equal to CBOD5 (see
Lung, 1998).
Loading rates for the nitrogenous component of oxygen demand (NBOD) are estimated from the influent concentration
and removal efficiencies of oxidizable nitrogen (TKN) for each level of treatment and the oxygen: nitrogen ratio of 4.57 g O2
pergN. Removal efficiencies for TKN are based on data compiled by: (a) Gunnerson et al. (1982) for primary (22
percent); (b) advanced primary (22 percent) assumed the same as primary, and (c) secondary (36 percent). TKN removal
efficiencies assigned for (d) advanced secondary (78 percent); and (e) advanced treatment (83 percent) are within the 25*
and 75th percentile ranges of data compiled for advanced secondary (72-92 percent) and advanced treatment (79-95
percent) from AMSA (1997). Less than secondary removal efficiencies are assigned as the mean of primary and advanced
primary removal percentages. Better than secondary removal efficiencies are assigned as the mean of advanced second-
ary and advanced treatment removal percentages.
The total ultimate BOD (BODu) load is calculated as the sum of the ultimate carbonaceous (CBODJ and nitrogenous
(NBOD) components of the effluent load of oxygen demanding substances. Table B-31 summarizes the influent and
effluent concentrations and removal efficiencies assumed for calculation of the loads of BOD5, CBODu, TKN, NBOD and
BOD.
B-22
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
Projection of Effluent Load Trends from 1996-2050
Projections of effluent loading trends for ultimate BOD are based on (a) U.S. Census Bureau "middle" population projec-
tions from 1996-2050 (U.S. Census, 1996); (b) constant wastewater inflow rate of 165 gpcd; (c) constant BODu influent
concentration of 396.5 mg/L; and (d) linear extrapolations of the percentage of projected population served by POTWs
and removal efficiencies for BOD5, CBODu, NBOD and BODu estimated for 1996 and 2016 using data obtained from the
1996 Clean Water Needs Survey (USEPA, 1997). It is assumed that the estimated design BODu removal efficiency (65
percent in 1996 and 71 percent in 2016) and the proportion of the United States population served by POTWs (72 percent
in 1996 and 88 percent in 2016) can be extrapolated linearly from 1996 to 2016. After 2016 it is assumed that these percent-
ages remain constant over time from 2016 to 2050 as 71 percent removal efficiency for BODu and 88 percent of the pro-
jected population served by POTWs.
Influent TSS and POC
The influent TSS concentration of 215 mg/L, consistent with other estimates of raw wastewater strength (e.g., Tetra Tech,
1999; Metcalf and Eddy, 1991), is based on the mean influent concentration from 60 wastewater facilities reported in
AMSA (1997). The influent concentration of POC (70.95 mg/L) was estimated from the particulate organic matter (POM)
(volatile suspended solids) fraction of influent TSS (POM:TSS=0.75) for "medium" strength raw wastewater and a C:DW
ratio of 0.44 mg C (mg DW)'1 (Metcalf and Eddy, 1991).
Effluent TSS and POC
Removal efficiencies for TSS are based on data compiled by (a) Gunnerson et al. (1982) for primary (50 percent); (b) NRC
(1993) for advanced primary (70 percent); and mean removal efficiencies computed from data reported by AMSA (1997)
for (c) secondary (92 percent); (d) advanced secondary (97 percent); and (e) advanced treatment (98 percent). Less than
secondary removal efficiencies are assigned as the mean of primary and advanced primary removal percentages. Better
than secondary removal efficiencies are assigned as the mean of advanced secondary and advanced treatment removal
percentages. Effluent concentrations of POC are estimated from particulate organic matter (volatile suspended solids)
fractions of TSS for primary and advanced primary (0.83), secondary and advanced secondary (0.67) obtained from Clark
et al. (1977). Data was not available to define the organic matter fraction of TSS for effluent from advanced treatment; a
value of 0.5 was assumed as a reasonable characterization of the organic matter fraction of effluent TSS. The organic
component of effluent TSS was converted to POC using a constant C:DW ratio of 0.44 mg C . (mg DW)'1 (Metcalf and
Eddy, 1991). Table B-32 summarizes the influent and effluent concentrations and removal efficiencies assumed for
calculation of the loads of TSS and POC.
B-23
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
References
AMSA. 1997. The AMSA financial survey. American Metropolitan Sewerage Association, Washington, DC.
ASIWPCA. 1984. America's clean water: The states evaluation of progress 1972-1982. Association of State and
Interstate Water Pollution Control Administrators (ASIWPCA), Washington, DC. Executive Summary and Technical
Appendix. Technical appendix provides state inventories of population served by municipal wastewater treatment
category and influent and effluent BOD5 loading for 1972 and 1982.
Clark, J.W., W. Viessman, and M.J. Hammer. 1977. Water supply and pollution control. 3rd ed. Harper & Row Publishers,
New York, NY.
Fair, G.M., J.C. Geyer, and D. A. Okun. 1971. Elements of water supply and wastewater disposal, 2nd ed. John Wiley &
Sons, Inc., New York, NY.
FWPCA. 1970. The economics of clean water. Vol. I, Detailed analysis. U.S. Department of the Interior, Federal Water
Pollution Control Administration (FWPCA), Washington DC, March 1970. Population served data for 1940 raw,
primary and intermediate and secondary treatment digitized from Figure 4, "Growth of Public Waste Handling
Services," pp. 75.
FWQA. 1970. Municipal waste facilities in the U.S.: Statistical summary, 1968 inventory. U.S. Department of the
Interior, Federal Water Quality Administration (FWQA), Washington, DC. Publication No. CWT-6.
Gunnerson, C.G., et al. 1982. Management of Domestic Waste. In Ecological stress and the New York Bight: Science
and management, ed. G.F. Mayer. Estuarine Research Foundation, Columbia, SC, pp. 91-112.
Hall, J.C, and R.J.Foxen. 1984. Nitrification in BOD5 test increases POTW noncompliance. WPCF55(12): 1461-1469.
Leo, W.M, R.V. Thomann and T.W. Gallagher. 1984. Before and after case studies: Comparisons of water quality follow-
ing municipal treatment plant improvements. EPA 430/9-007. Office of Water, Program Operations, U.S. Environmen-
tal Protection Agency, Washington, D.C.
Lung, W. 1998. Trends in BOD/DO modeling for waste load allocations. ASCEEnviron. Eng. 124(10): 1004-1007.
Metcalf and Eddy. 1991. Wastewater engineering: Treatment, disposal and reuse. 3rded. McGraw-Hill Series in Water
Resources and Environmental Engineering, New York, NY.
MWCOG .1989. Potomac River water quality, trends and issues in the Washington Metropolitan Area, 1982-1986,
Metropolitan Council of Governments, Washington DC. April.
NCWQ. 1976. Staff Report to the National Commission on Water Quality, U.S. Government Printing Office, Washington,
DC, p. II-5. Municipal facility inventory data for 1940 and 1974 taken from numerical data presented in FWQA (1970)
figure "Trends in Municipal Wastewater Treatment" for 1940 (2,938 primary, 2,630 secondary for a total of 5,568) and
1974 (3,032 primary, 16,987 secondary, 992 tertiary for a total of 21,011 facilities).
NRC. 1993. Managing wastewater in coastal urban areas. Committee on Wastewater Management for Coastal Urban
Areas, Water Science and Technology Board, Commission on Engineering and Technical Systems, National Research
Council, National Academy Press, Washington, DC.
Steel, E.W. 1960. Water supply and sewerage, 4th ed. McGraw-Hill, New York, NY.
Tetra Tech. 1999. Improving point source loadings data for reporting national water quality indicators. Final tech.
report prepared for U.S. Environmental Protection Agency, Office of Wastewater Management, Washington, DC, by
Tetra Tech, Inc., Fairfax, VA.
Thomann, R.V, and J.A. Mueller. 1987. Principles of surface water quality modeling and control. Harper & Row, Inc.,
New York, NY
U.S. Census. 1996. Population projections of the United States by age, sex, race and Hispanci origin: 1995-2050.
Current Population Reports, Population Division, U.S. Bureau of Census, Washington, DC.
USDOI. 1970. Municipal waste facilities in the U.S.: Statistical summary, 1968 inventory. U.S. Department of the
Interior, Federal Water Quality Administration (FWQA), Washington DC. Publication No. CWT-6.
USEPA. 1972. Working file notes from EPA Office of Municipal Pollution Control, Washington, DC. Handwritten tables
compiled from November 1972 EPA STORET data extraction and tabulation of population served and facilities
inventory for raw, primary, intermediate (advanced primary), secondary and tertiary treatment. Detailed types of
waste treatment facilities are compiled. Secondary treatment category (total of 14,035 facilities serving 102.3 million
persons) included the following subcategories: other; activated sludge; extended aeration; high rate trickling filters;
standard rate trickling filter; intermediate sand filtration; land application; oxidation pond; unknown filter; and
unknown. Primary data sources reproduced in Table B-34 and Table B-35.
B-24
-------
Appendix B: National Municipal Wastewater Inventory and Infrastructure, 1940 to 2016
USEPA. 1974. National water quality inventory, 1974. Report to Congress. Office of Water Planning and Standards,
U.S. Environmental Protection Agency, Washington, DC. EPA-440/9-74-001, Vol. I and Vol. II. Population served and
number of facilities for raw, primary, secondary and tertiary for 1962,1968, and 1973 compiled on p. 278. Data from
1962 and 1968 is from USPHS Municipal Waste Inventories. Data for 1973 is from STORE! database.
USEPA. 1976. 1976 NEEDS survey, conveyance and treatment of municipal wastewater. Summaries of technical data.
Water Program Operations, U.S. Environmental Protection Agency, Washington, DC. Data not available for popula-
tion served by no discharge, raw discharges or tertiary treatment. Data not available for facilities inventory.
USEPA. 1978. 1978 NEEDS survey, conveyance and treatment of municipal wastewater. Summaries of technical data.
Water Program Operations, U.S. Environmental Protection Agency, Washington, D.C. Data not available for raw
effluent flow.
USEPA. 1980. 1980 NEEDS survey, conveyance and treatment of municipal wastewater. Summaries of technical data.
Office of Water Program Operations, U.S. Environmental Protection Agency, Washington, DC. Data not available for
raw effluent flow.
USEPA. 1982. 1982 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC. Data not available for raw effluent flow.
USEPA. 1984. 1984 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC. Data not available for raw effluent flow.
USEPA. 1986. 1986 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC. Data not available for raw effluent flow.
USEPA. 1989. 1988 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC.
USEPA. 1993. 1992 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC. EPA-832-R-93-002.
USEPA. 1997. 1996 NEEDS survey, conveyance, treatment, and control of municipal wastewater, combined sewer
overflows and stormwater runoff. Summaries of technical data. Office of Water Program Operations, U.S. Environ-
mental Protection Agency, Washington, DC. EPA-832-R-97-003.
USPHS. 1951. Water Pollution in the United States. A Report on the Polluted Conditions of our Waters and What is
Needed to Restore their Quality. U.S. Federal Security Agency, Public Health Service, Washington, DC. NTIS No.
PB-218-308/BA. Population served and facilities inventory data for raw, primary and secondary treatment compiled
for 1950 (pp. 31-33) by major river basins.
B-25
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
B-26
-------
Appendix C
National Public and
Private Sector Investment
in Water Pollution Control
Table
C-1
C-2
C-3
CM
U.S. Environmental Protection Agency Construction Grants Program and Clean Water
State Revolving Fund expenditures for municipal water pollution control
Water pollution control abatement, current year-dollar
Water pollution control abatement, constant-dollar
Gross domestic product index and plant construction index used for inflation adjustment of
O&M and capital expenditures
C-3
C^
C-4
C-5
C-1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
C-2
-------
Appendix C: National Public and Private Sector Investment in Water Pollution Control
Table C-1. U.S. Environmental Protection Agency Construction Grants Program and Clean Water State Revolving
Fund expenditures for municipal water pollution control
Year
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Annual
CURRENT
($1000)
139
31
132080
3043502
2519179
4343443
4598985
7272400
2832399
5112276
3807997
3605439
2250355
3988124
4565966
2129228
2319335
2442281
3062053
1295664
945677
279960
284006
118912
105055
11065
0
0
0
0
0
Constructii
Cumulative
CURRENT
($1000)
139
170
132250
3175752
5694931
10038374
14637359
21909759
24742158
29854434
33662431
37267870
39518225
43506349
48072315
50201543
52520878
54963159
58025212
59320876
60266553
60546513
60830519
60949431
61054486
61065551
61065551
61065551
61065551
61065551
61065551
1321677
587221
59156653
0
61065551
DH urants— •
Annual
1995$
($1000)
512
100
364950
8006876
5774008
9027401
9075865
13507911
4907498
8119248
5526847
4602088
2716928
4770899
5363493
2481372
2761491
2859376
3389277
1382068
1002530
293754
300577
125501
108193
11065
0
0
0
0
0
J
Cumulative
1995$
($1000)
512
612
365562
8372438
14146446
23173847
32249712
45757623
50665121
58784369
64311216
68913304
71630232
76401131
81764624
84245996
87007487
89866863
93256140
94638208
95640738
95934492
96235069
96360570
96468763
96479828
96479828
96479828
96479828
96479828
96479828
1962605
842962
93674326
-65
96479828
L wicc
Annual
CURRENT
($1000)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
252227
1153764
1368882
1971827
1891382
1890597
1270191
1318463
1714318
792498
1240294
1299931
0
Grants data matched
III VVQLC7I UIUIW 1 n
Cumulative
CURRENT
($1000)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
252227
1405991
2774873
4746700
6638082
8528678
9798870
11117332
12831650
13624148
14864442
16164373
16164373
to River Basins >
Annual
1995$
($1000)
0
0
0
0
0
0
0
0
0
0
0
0
0
279181
1230703
1451183
2068972
2001739
1995337
1308148
1318463
NA
NA
NA
NA
NA
18
Cumulative
1995$
($1000)
0
g
Q
g
Q
g
g
Q
Q
g
g
Q
g
Q
g
g
Q
279181
1509883
2961067
5030039
7031778
9027115
10335264
11653726
NA
NA
NA
NA
NA
Grants data not matched to any CU
Grants data matched
Rounding error
Grants data for all
to River Basins 1
grants, USA total
-18
Sources: Construction Grants Program expenditures extracted August, 1995 from USEPA "GICS" database, Clean water State Revolving
Fund (CWSRF) expenditures obtained from USEPA Office of Wastewater Management, CWSRF Program, April, 2000
C-3
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Table C-2. Water pollution control abatement, current year-dollar (million $) Source: Vogan (1996)
Year
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
private
cap
P e
1,501
1,770
1,765
2,145
2, 607
2,827
2, 683
2, 873
2,795
2,848
2,937
2,422
2, 730
2, 670
2, 534
2, 614
2, 581
3, 196
4,430
4,666
4,532
4,335
4,720
0
private
o&m
p&e
789
972
1, 188
1,409
1,726
2, 064
2,357
2,788
2, 985
3,210
3,466
3,753
4, 052
4,350
4,741
5, 088
5, 427
5,767
6,492
6,223
6,522
6, 513
7,057
0
private
2 ,290
2, 742
2,953
3,554
4,333
4,891
5,040
5,661
5,780
6, 058
6, 403
6,175
6,782
7,020
7,275
7,702
8,008
8,963
10,922
10,889
11,054
10,848
11,777
0
public public
capital capital
2,260
2,534
3,105
3,762
4,082
4,287
4, 992
5, 945
6, 592
6,404
5,851
5,735
5, 794
6,193
6, 884
7,803
8,322
8, 350
8,730
9,015
9,589
5,126
0
0
29
22
29
32
36
52
63
81
61
57
86
73
54
63
40
37
28
49
77
64
14
11
10
0
public
capital
2,289
2,556
3,134
3,794
4, 118
4,339
5,055
6,026
6,653
6,461
5, 937
5, 808
5,848
6,256
6, 924
7, 840
8,350
8,399
8,807
9,079
9,603
5,137
10
0
public public ]
o&m o&m
sewer elec ut
1,125
1,308
1,567
1, 838
2, 156
2,553
2,977
3,399
3,915
4, 556
5, 168
5,643
6,057
6,554
7,201
7,792
8,363
9,325
10,262
10, 995
11,929
6,220
0
0
3
4
5
7
9
10
10
12
13
18
17
19
20
10
10
13
12
11
8
14
10
11
10
0
public public
o&m o&m
other tot O&M
0 1,128
1 1,313
1 1,573
0 1, 845
1 2,166
0 2,563
1 2,988
1 3,412
0 3,928
1 4,575
2 5,187
2 5,664
2 6,079
3 6,567
3 7,214
3 7, 808
3 8,378
3 9,339
3 10,273
3 11,012
3 11,942
3 6,234
3 13
0 0
public
cap+o&m
tot pub
3,416
3,869
4, 706
5,639
6,283
6,902
8, 043
9,438
10, 581
11, 035
11,123
11,472
11,927
12,823
14,138
15,648
16,727
17, 737
19, 080
20, 091
21,545
11,371
23
0
Pub+Priv
cap+o&m
Tot-Point
5,706
6, 611
7 , 659
9,193
10,616
11,793
13, 083
15, 099
16,361
17,093
17,526
17,647
18,709
19,843
21,413
23,350
24,735
26, 700
30, 002
30, 980
32,599
22,219
11, 800
0
Table C-3. Water pollution control abatement, constant-dollar (1995$ GDP index for O&M; PCI for capital)
(million $)
Year
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
private
cap
p&e
4, 147
4, 657
4, 045
4,458
5, 145
5,251
4, 649
4, 563
4, 057
3, 635
3,546
2,897
3,207
3,112
3,017
3,060
2,857
3,409
4,696
4, 896
4,796
4,575
4, 861
0
private
o&m
p&e
2, 642
3,057
3,437
3,720
4,287
4, 796
5, 078
5, 521
5,408
5,285
5,373
5, 591
5, 784
5, 986
6,356
6, 609
6, 785
6,904
7,443
6, 874
7,008
6, 851
7,270
0
private public
capital
tot sewer
6,789
7,714
7,482
8, 178
9,432
10,047
9,726
10,084
9,465
8, 920
8, 919
8,488
8, 991
9, 097
9, 373
9, 670
9, 642
10,314
12,140
11,770
11,804
11, 426
12,131
0
6,243
6,666
7, 116
7, 819
8,055
7,962
8,649
9,442
9,567
8, 174
7, 063
6, 860
6, 807
7,217
8, 196
9,136
9,211
8, 906
9,255
9,459
10, 148
5, 410
0
0
public public publi
elec
80
58
66
67
71
97
109
129
89
73
104
87
63
73
48
43
31
52
82
67
15
12
10
0
ut tot K sewe
6,323
6,724
7, 182
7,885
8, 126
8, 058
8,758
9,570
9,655
8,246
7, 167
6, 947
6,870
7,291
8,243
9, 179
9,242
8, 959
9,337
9,526
10, 163
5, 422
10
0
3,765
4, 114
4, 532
4,851
5,354
5, 933
6, 412
6,730
7,093
7,500
8,010
8, 406
8,645
9, 018
9, 653
10,122
10,455
11, 164
11, 766
12, 144
12, 817
6,542
0
0
c public public public public Pub+Priv
m o&m o&m o&m cap + o&m cap+o&m
r elec ut other tot O&M tot pub Tot-Point
10
12
15
20
23
24
22
25
26
33
28
29
29
14
13
17
15
13
9
16
11
11
10
0
0
3
3
0
3
0
2
2
0
2
3
3
3
4
4
4
4
4
3
3
3
3
3
0
3,775
4, 130
4, 550
4, 871
5, 380
5,956
6,437
6, 757
7, 118
7, 535
8, 042
8,438
8,677
9,036
9,670
10, 142
10,474
11, 180
11, 778
12, 163
12,831
6,557
13
0
10, 098
10, 854
11, 732
12,757
13, 505
14, 015
15, 195
16, 327
16, 774
15,781
15,209
15,385
15, 547
16, 326
17, 914
19, 321
19,715
20, 139
21, 115
21, 690
22,994
11,978
23
0
16, 887
18,568
19,214
20,935
22, 937
24,062
24, 921
26, 411
26,238
24,701
24, 128
23, 874
24, 538
25,424
27,287
28, 991
29,357
30,453
33,254
33,459
34,798
23,404
12, 154
0
Total 93537
C-4
-------
Appendix C: National Public and Private Sector Investment in Water Pollution Control
Table C-4. Gross Domestic Product Index and Plant Cost Index used for inflation adjustment of O&M
and capital expenditures. Source: Council of Economic Advisors (1997) and CE (1995).
FY
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
O&M
GDP
25
26
26
26
27
27
28
29
30
31
33
35
37
38
41
44
49
52
55
60
65
71
78
83
87
91
94
96
100
103
108
113
117
120
123
126
129
.6
.0
.3
.9
.2
.7
.4
.4
.3
.8
.4
.2
.1
.8
.3
.9
.2
.3
.9
.3
.6
.7
.9
.8
.2
.0
.4
.9
.0
.9
.5
.3
.6
.9
.5
.1
.9
Capital
PCI
137.
144.
165.
182.
192.
204.
218.
238.
261.
297.
314.
316.
322.
325.
318.
323.
342.
355.
357.
361.
358.
359.
368.
379.
2
1
4
4
1
1
8
7
2
0
0
9
7
3
4
8
5
4
6
3
2
2
1
1
C-5
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
References
CE. 1995. Economic indicators: Chemical engineering plant cost index. Chemical Engineering, The McGraw
Hill Companies, Vol. 102,No.7pp. 192.
Council of Economic Advisors. 1997. Table B-3, Chain Type price indexes for gross domestic product, 1959-
96, Appendix B, Statistical Tables Relating to Income, Employment and Production. In: Economic Report
to the President, Transmitted to the Congress, February, 1997 together with the Annual Report of the
Council of Economic Advisors, U.S. Government Printing Office, Washington, DC.
Vogan, C.R. 1996. Pollution abatement and control expenditures, 1972-94. Survey of current business.
Vol. 76, No. 9, pp. 48-67. U.S. Dept. of Commerce, Bureau of Economic Analysis, Washington, DC.
C-6
-------
Appendix D
Before and After CWA Changes
in 10th Percentile Dissolved
Oxygen and 90th Percentile
BOD5 at the Catalog Unit Level
Table Page
D-1 Before and After CWA Changes in 10th Percentile Dissolved Oxygen at the Catalog Unit Level D-3
D-2 Before and After CWA Changes in 90th Percentile BOD5 at the Catalog Unit Level D-7
D-1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
D-2
-------
Appendix D: Before and After CWA Changes in DO and BODS at the Catalog Unit Level
Table D-1 . Before and After CWA Changes in 1 0th Percentile Dissolved Oxygen (mg/L) at the Catalog Unit
Rank
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
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
Catalog
Unit No.
04030204
04120102
04110002
17010307
07070002
18060005
02050306
04030104
05080002
08030204
10170203
04040002
08030203
04040003
06010104
08030205
06010205
02040204
04100002
11070207
04040001
18090208
07120007
07130011
04100009
04130003
06010102
05050008
02040203
04110001
07090001
03010106
07130006
07120004
06010105
05030103
05080001
02040202
03100204
14010005
05090101
05050003
07010204
04030101
07140201
02040201
03170006
09020301
03100101
02070003
05030101
05030202
07130001
05090202
07120006
07090004
01080205
02070008
17050115
06010207
18070203
04090001
05090201
05120201
08020401
07060005
03050109
Catalog Unit
Name
LOWER FOX. WISCONSIN
CATTARAUGUS . NEW YOR
CUYAHOGA. OHIO.
LOWER SPOKANE. WASHI
LAKE DUBAY. WISCONSI
SALINAS. CALIFORNIA.
LOWER SUSQUEHANNA. M
OCONTO. WISCONSIN.
LOWER GREAT MIAMI . I
COLDWATER. MISSISSIP
LOWER BIG SIOUX. IOW
PIKE-ROOT. ILLINOIS
YOCONA. MISSISSIPPI.
MILWAUKEE. WISCONSIN
HOLSTON. TENNESSEE.
YALOBUSHA. MISSISSIP
UPPER CLINCH. TENNES
DELAWARE BAY. NEW JE
RAISIN. MICHIGAN OHI
SPRING. KANSAS MISSO
LITTLE CALUMET-GALIE
MQJAVE. CALIFORNIA.
LOWER FOX. ILLINOIS.
LOWER ILLINOIS. ILLI
LOWER MAUMEE . OHIO .
LOWER GENESEE . NEW Y
SOUTH FORK HOLSTON.
LOWER KANAWHA. WEST
SCHUYLKILL. PENNSYLV
BLACK-ROCKY. OHIO.
UPPER ROCK. ILLINOIS
ROANOKE RAPIDS. NORT
UPPER SANGAMON. ILLI
DES PLAINES. ILLINOI
UPPER FRENCH BROAD.
MAHONING. OHIO PENNS
UPPER GREAT MIAMI . I
LOWER DELAWARE . NEW
ALAFIA. FLORIDA.
COLORADO HEADWATERS-
RACCOON-SYMMES . OHIO
GREENBRIER. WEST VIR
CROW. MINNESOTA.
MANITOWOC-SHEBOYGAN .
UPPER KASKASKIA. ILL
CROSSWICKS-MESHAMINY
PASCAGOULA. MISSISSI
SANDHILL-WILSON. MIN
PEACE. FLORIDA.
CACAPON-TCWN. MARYLA
UPPER OHIO. OHIO PEN
UPPER OHIO-SHADE. OH
LOWER ILLINOIS-SENAC
LITTLE MIAMI . OHIO .
UPPER FOX. ILLINOIS
SUGAR. ILLINOIS WISC
LOWER CONNECTICUT. C
MIDDLE POTOMAC-CATOC
MIDDLE SNAKE-PAYETTE
LOWER CLINCH. TENNES
SANTA ANA. CALIFORNI
ST. CLAIR. MICHIGAN.
OHIO BRUSH-WHITEOAK.
UPPER WHITE. INDIANA
LOWER ARKANSAS . ARKA
APPLE-PLUM. ILLINOIS
SALUDA. SOUTH CAROLI
Mean
Before
CWA
0.160
1.323
0.295
3.500
0.880
3.180
0.880
0.500
1.185
0.000
0.000
0.940
0.000
2.180
0.157
0.000
1.614
0.530
4.059
1.600
0.570
4.020
3.780
1.940
2.068
1.043
2.623
1.463
3.830
1.688
2.760
1.423
0.000
1.477
4.100
2.627
3.533
1.298
2.598
4.880
3.200
3.233
4.200
5.010
3.260
3.446
2.266
4.100
4.030
4.600
4.530
3.765
4.174
4.005
4.595
5.900
4.300
5.100
6.470
5.260
3.833
5.213
4.400
3.802
5.650
3.946
2.645
Mean
After
CWA
7.205
7.600
6.501
9.700
6.683
8.750
6.196
5.800
6.468
5.208
5.143
5.940
4.854
6.957
4.869
4.629
6.082
4.910
8.340
5.625
4.555
7.977
7.576
5.722
5.847
4.710
6.183
5.013
7.367
4.910
5.980
4.608
3.130
4.605
7.033
5.540
6.443
4.172
5.387
7.560
5.835
5.720
6.680
7.490
5.700
5.815
4.541
6.347
6.250
6.800
6.702
5.830
6.186
5.999
6.550
7.800
6.163
6.937
8.300
7.081
5.633
7.000
6.170
5.552
7.390
5.582
4.270
# Stations
Differ-
ence
7.045
6.277
6.206
6.200
5.803
5.570
5.316
5.300
5.282
5.208
5.143
5.000
4.854
4.777
4.712
4.629
4.468
4.380
4.281
4.025
3.985
3.957
3.796
3.783
3.780
3.668
3.560
3.550
3.537
3.222
3.220
3.186
3.130
3.128
2.933
2.913
2.909
2.874
2.789
2.680
2.635
2.487
2.480
2.480
2.440
2.369
2.275
2.247
2.220
2.200
2.172
2.065
2.012
1.994
1.955
1.900
1.863
1.837
1.830
1.821
1.800
1.787
1.770
1.750
1.740
1.636
1.625
Before
CWA
1
3
2
1
1
4
1
1
6
1
1
1
1
2
1
1
1
1
17
1
2
2
2
1
8
4
3
3
1
6
1
4
1
18
1
6
3
16
4
1
1
3
1
3
6
7
5
2
4
1
1
2
9
2
2
1
1
1
1
2
6
6
1
37
2
5
6
After
CWA
6
2
25
1
3
1
10
2
4
11
9
1
16
3
5
11
7
8
2
4
11
3
11
20
7
2
10
7
9
6
8
6
21
49
7
2
4
24
3
2
3
1
2
5
11
4
13
3
2
1
39
3
14
15
39
2
7
14
1
4
9
1
3
14
2
6
68
Level
# Q years
Before
CWA
2
4
5
1
2
4
4
1
4
2
3
2
2
3
2
3
3
5
4
2
2
4
3
3
5
4
2
3
4
5
4
3
2
3
1
5
4
4
2
2
4
4
3
1
3
4
2
2
3
5
5
4
3
3
3
2
4
5
1
1
5
4
3
3
2
2
14
After
CWA
3
2
1
2
3
4
1
3
1
3
2
1
4
1
2
4
2
3
1
2
1
4
1
3
1
1
3
2
1
1
1
3
2
1
2
1
1
1
4
3
3
1
3
1
3
1
2
3
4
2
1
3
1
1
1
1
1
2
3
3
3
1
3
1
4
2
D-3
-------
Progress in Water Quality: An Evaluation of the National Investment In Municipal Wastewater Treatment
Rank
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
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
Catalog
Unit No.
17060107
02040205
07010206
07070003
03050103
10190006
10200203
05120114
03180004
04140203
05020002
17080005
05030203
07120005
07030005
06010108
070900Q6
07010207
17020006
05040005
18080003
06030005
18020103
03170008
14070006
11070103
06030001
11140208
07140106
05010009
08050003
03170001
05050002
02070007
05120202
08090203
07040001
03140305
02050103
17110013
08030100
05130108
05120103
17060110
17080001
05120111
11110207
04090005
11110104
06020001
08040303
17110007
17010305
08040304
03050208
17110019
10190007
17110011
07090005
05050005
07130002
10190018
04110003
10200101
17020015
07070005
04110004
04080204
08040302
08030206
07130003
07120003
05120106
Catalog Unit
Name
LOWER SNAKE-TUCANNON
BRANDYWINE-CHRISTINA
TWIN CITIES . MINNESO
CASTLE ROCK. WISCONS
LOWER CATAWBA. NORTH
BIG THOMPSON. COLORA
SALT. NEBRASKA.
LITTLE WABASH. ILLIN
LOWER PEARL . LOUISIA
OSWEGO. NEW YORK.
WEST FORK. WEST VIRG
LOWER COWLITZ . WASH!
LITTLE KANAWHA. WEST
UPPER ILLINOIS . ILLI
LOWER ST. CROIX. MIN
NOLICHUCKY. NORTH CA
KISHWAUKEE. ILLINOIS
RUM. MINNESOTA.
OKANOGAN. WASHINGTON
WILLS. OHIO.
HONEY-EAGLE LAKES. C
PICKWICK LAKE. ALABA
SACRAMENTO-LOWER THO
ESCATAWPA. ALABAMA M
LOWER LAKE POWELL. A
MIDDLE VERDIGRIS. KA
GUNTERSVILLE LAKE. A
SALINE BAYOU. LOUISI
BIG MUDDY. ILLINOIS.
LOWER ALLEGHENY. PEN
TENSAS. LOUISIANA.
CHUNKY-OKATIBBEE. MI
MIDDLE NEW. VIRGINIA
SHENANDOAH. VIRGINIA
LOWER WHITE . INDIANA
EASTERN LOUISIANA CO
RUSH-VERMILLION. MIN
ESCAMBIA. ALABAMA FL
OWEGO-WAPPASENING. N
DUWAMISH. WASHINGTON
LOWER MISSISSIPPI -GR
CANEY. TENNESSEE.
MISSISSINEWA. INDIAN
LOWER SNAKE. WASHING
LOWER COLUMBIA-SANDY
MIDDLE WABASH-BUSSER
LOWER ARKANSAS-MAUME
HURON. MICHIGAN.
ROBERT S . KERR RESER
MIDDLE TENNESSEE-CHI
DUGDEMONA. LOUISIANA
LOWER SKAGIT. WASHIN
UPPER SPOKANE. IDAHO
LITTLE. LOUISIANA.
BROAD-ST. HELENA. SO
PUGET SOUND. WASHING
CACHE LA POUDRE. COL
SNOHOMISH. WASHINGTO
LOWER ROCK. ILLINOIS
GAULEY. WEST VIRGINI
VERMILION. ILLINOIS.
LOWER SOUTH PLATTE.
ASHTABULA-CHAGRIN. 0
MIDDLE PLATTE-BUFFAL
LOWER CRAB. WASHINGT
LOWER WISCONS IN. WIS
GRAND. OHIO.
FLINT. MICHIGAN.
CASTOR. LOUISIANA.
UPPER YAZOO. MISSISS
LOWER ILLINOIS-LAKE
CHICAGO. ILLINOIS IN
TIPPECANOE. INDIANA.
Mean
Before
CWA
7.600
4.600
3.851
5.000
2.273
5.443
3.750
2.340
3.777
4.300
5.325
7.564
4.403
5.077
5.731
5.580
5.000
5.800
6.460
4.220
6.820
4.800
8.385
2.078
6.380
5.010
4.850
4.160
2.290
6.060
3.100
4.433
5.000
5.260
4.725
4.550
4.857
5.120
6.080
6.001
5.100
4.200
5.840
7.170
7.800
5.100
6.360
5.000
5.620
4.340
3.000
9.420
7.200
3.250
2.287
8.043
6.391
8.360
5.253
7.090
3.775
6.220
5.225
6.800
6.680
6.365
5.665
5.400
3.440
5.520
4.078
3.416
6.135
Mean
After
CWA
9.200
6.126
5.373
6.515
3.771
6.901
5.195
3.754
5.185
5.700
6.691
8.930
5.743
6.412
7.057
6.900
6.280
7.080
7.725
5.480
8.040
5.968
9.550
3.232
7.500
6.117
5.935
5.240
3.366
7.132
4.168
5.500
6.066
6.307
5.750
5.548
5.853
6.100
7.047
6.957
6.020
5.110
6.715
8.030
8.625
5.892
7.140
5.750
6.367
5.071
3.725
10.117
7.895
3.938
2.970
8.720
7.038
8.987
5.866
7.685
4.370
6.800
5.793
7.305
7.180
6.830
6.120
5.850
3.870
5.948
4.489
3.824
6.525
# Stations
Differ-
ence
1.600
1.526
1.522
1.515
1.498
1.458
1.445
1.414
1.408
1.400
1.366
1.366
1.340
1.334
1.326
1.320
1.280
1.280
1.265
1.260
1.220
1.168
1.165
1.153
1.120
1.107
1.085
1.080
1.076
1.072
1.068
1.067
1.066
1.047
1.025
0.998
0.996
0.980
0.967
0.956
0.920
0.910
0.875
0.860
0.825
0.792
0.780
0.750
0.747
0.730
0.725
0.697
0.695
0.688
0.683
0.677
0.647
0.627
0.613
0.595
0.595
0.580
0.568
0.505
0.500
0.465
0.455
0.450
0.430
0.428
0.412
0.407
0.390
Before
CWA
1
1
23
1
13
8
2
1
7
1
4
5
6
4
9
1
1
1
2
1
1
1
4
6
1
1
2
1
1
1
1
3
2
1
2
1
10
2
1
9
1
1
1
1
1
1
2
2
1
15
1
2
2
4
4
7
12
2
3
1
2
3
5
1
3
2
3
3
1
1
5
13
2
After
CWA
1
23
64
4
22
11
20
11
4
1
2
4
6
10
7
2
12
3
2
3
1
5
2
12
1
4
13
1
36
19
5
1
7
3
3
4
6
1
3
7
1
1
6
1
2
23
7
2
3
34
2
3
11
2
11
1
6
3
23
5
4
1
3
2
1
2
3
2
2
5
14
19
2
# Q years
Before
CWA
1
4
3
2
2
2
3
3
1
4
4
2
4
3
3
1
4
3
2
4
3
1
3
2
1
2
1
4
3
4
3
4
3
5
3
2
3
2
4
2
3
1
3
3
2
3
2
4
4
1
4
3
1
4
1
1
2
3
3
4
2
1
5
3
1
2
5
4
4
2
3
2
3
After
CWA
2
1
3
3
2
1
1
2
1
2
2
2
2
1
3
2
1
3
3
3
4
4
2
2
1
3
3
4
2
1
4
3
2
2
1
2
2
2
1
3
4
3
1
3
1
1
4
1
3
3
4
3
2
3
2
2
1
4
1
2
2
1
i
1
2
2
1
1
4
4
2
1
1
D-4
-------
Appendix D: Before and After CWA Changes in DO and BODS at the Catalog Unit Level
Rank
141
142
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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
Catalog
Unit No .
03050202
14080105
04030108
07080209
10270205
10200202
18030012
05020006
18040005
06010103
10180009
05080003
04080206
08040207
05050007
08070205
03040201
02070001
17020011
05070101
07020012
05140101
03180005
03050205
17090003
05120112
02070004
03160203
05050006
09030004
05020003
05020001
07090003
06030002
05070204
02070010
03040204
05050001
08040301
07140204
07040007
10240011
17110008
03050101
02080206
04080201
04030202
07080208
08050002
08040202
05120105
08080203
05020004
06040006
05070102
07040006
10300101
07040002
07020007
07010203
05120104
17100103
03040202
03160106
07140101
03050105
07050005
04030105
10170101
05120108
08040206
05010006
03050207
Catalog Unit
Name
SOUTH CAROLINA COAST
MIDDLE SAN JUAN. ARI
MENOMINEE. MICHIGAN
LOWER IOWA. IOWA.
LOWER BIG BLUE. KANS
LOWER PLATTE. NEBRAS
TULARE-BUENA VISTA L
YOUGHIOGHENY. MARYLA
LOWER COSUMNES-LOWER
WATAUGA. NORTH CAROL
MIDDLE NORTH PLATTE-
WHITEWATER. INDIANA
SAGINAW. MICHIGAN.
LOWER OUACHITA. LOUI
ELK. WEST VIRGINIA.
TANGIPAHOA. LOUISIAN
LOWER PEE DEE. NORTH
SOUTH BRANCH POTOMAC
WENATCHEE. WASHINGTO
UPPER GUYANDOTTE . WE
LOWER MINNESOTA. MIN
SILVER-LITTLE KENTUC
BOGUECHITTO. LOUISI
EDISTO. SOUTH CAROLI
UPPER WILLAMETTE. OR
EMBARRAS. ILLINOIS.
CONOCOCHEAGUE-OPEQUO
LOWER TAMBIGBEE . ALA
UPPER KANAWHA. WEST
UPPER RAINY. MINNESO
UPPER MONONGAHELA. P
TYGART VALLEY. WEST
PECATONICA. ILLINOIS
WHEELER LAKE . ALABAM
BIG SANDY. KENTUCKY
MIDDLE POTOMAC-ANACO
LITTLE PEE DEE . NORT
UPPER NEW. NORTH CAR
LOWER RED. LOUISIANA
LOWER KASKASKIA. ILL
BLACK. WISCONSIN.
INDEPENDENCE-SUGAR .
STILLAGUAMISH. WASHI
UPPER CATAWBA. NORTH
LOWER JAMES . VIRGINI
TITTABAWASSEE. MICHI
WOLF. WISCONSIN.
MIDDLE IOWA. IOWA.
BAYOU MACON. ARKANSA
LOWER OUACHITA-BAYOU
MIDDLE WABASH-DEER.
UPPER CALCASIEU. LOU
CHEAT. PENNSYLVANIA
LOWER TENNESSEE. KEN
LOWER GUYANDOTTE . WE
LA CROSSE-PINE. MINN
LOWER MISSOURI-CROOK
CANNON. MINNESOTA.
MIDDLE MINNESOTA. MI
CLEARWATER-ELK. MINN
EEL. INDIANA.
UPPER CHEHALIS . WASH
LYNCHES . NORTH CAROL
MIDDLE TOMBIGBEE-LUB
CAHOKIA- JOACHIM. ILL
UPPER BROAD. NORTH C
LOWER CHIPPEWA. WISC
PESHTIGO. WISCONSIN.
LEWIS AND CLARK LAKE
MIDDLE WABASH-LITTLE
BAYOU D'ARBONNE. ARK
MIDDLE ALLEGHENY-RED
SALKEHATCHIE . SOUTH
Mean
Before
CWA
3.553
4.790
6.440
6.540
5.880
6.900
7.240
7.197
8.460
6.095
7.000
6.880
4.899
4.000
6.400
6.200
4.120
6.300
9.300
6.400
5.439
3.400
6.000
4.006
7.657
5.080
6.040
5.988
7.050
7.200
6.325
7.028
5.500
5.486
5.720
4.340
3.686
5.973
5.450
4.130
7.450
5.420
8.675
4.667
6.140
6.035
7.205
3.827
3.700
2.635
6.860
4.590
6.886
5.400
6.387
6.740
5.150
7.260
6.803
6.200
7.000
7.900
4.917
5.520
4.490
6.700
5.980
6.240
7.500
6.800
2.880
8.000
3.805
Mean
After
CWA
3.932
5.160
6.750
6.845
6.170
7.173
7.500
7.446
8.700
6.333
7.233
7.100
5.117
4.200
6.577
6.353
4.270
6.450
9.450
6.545
5.580
3.530
6.100
4.053
7.699
5.102
6.060
5.967
6.990
7.135
6.250
6.926
5.388
5.368
5.550
4.160
3.480
5.734
5.200
3.864
7.180
5.125
8.360
4.321
5.774
5.660
6.825
3.445
3.287
2.220
6.435
4.162
6.432
4.930
5.850
6.200
4.586
6.662
6.197
5.541
6.290
7.185
4.189
4.776
3.658
5.867
5.100
5.300
6.548
5.802
1.867
6.977
2.770
# Stations
Differ-
ence
0.379
0.370
0.310
0.305
0.290
0.273
0.260
0.249
0.240
0.238
0.233
0.220
0.218
0.200
0.177
0.153
0.150
0.150
0.150
0.145
0.141
0.130
0.100
0.047
0.042
0.022
0.020
-0.020
-0.060
-0.065
-0.075
-0.102
-0.112
-0.119
-0.170
-0.180
-0.205
-0.240
-0.250
-0.266
-0.270
-0.295
-0.315
-0.345
-0.366
-0.375
-0.380
-0.382
-0.413
-0.415
-0.425
-0.428
-0.454
-0.470
-0.537
-0.540
-0.564
-0.598
-0.607
-0.660
-0.710
-0.715
-0.728
-0.744
-0.832
-0.833
-0.880
-0.940
-0.952
-0.998
-1.013
-1.023
-1.035
Before
CWA
3
1
1
1
1
1
1
11
2
2
1
1
19
2
1
2
19
1
1
2
17
1
2
5
6
1
1
8
2
1
6
6
1
2
1
1
9
3
1
1
1
1
2
3
1
2
2
6
2
4
1
6
8
1
3
1
1
1
6
1
1
2
17
1
1
1
3
1
1
3
1
2
2
# Q years
After Before
CWA CWA
9
1
2
2
2
2
2
5
1
3
8
1
3
1
7
3
39
1
2
4
8
5
2
7
7
15
14
15
2
4
19
4
6
13
2
81
11
17
2
19
3
2
1
36
20
3
2
6
3
7
1
5
4
4
2
2
5
6
3
18
2
2
18
7
16
29
1
1
3
7
3
26
7
2
2
1
2
2
2
3
4
3
1
2
3
4
4
4
3
2
4
1
3
2
2
2
1
1
3
5
2
3
1
4
4
2
1
3
5
2
1
4
3
2
3
3
1
3
3
1
2
3
4
2
4
4
3
3
3
3
2
3
3
3
2
2
2
2
1
4
1
1
3
3
4
1
After
CWA
3
1
3
2
1
1
4
1
3
3
2
1
1
4
2
2
3
1
4
1
3
1
2
3
1
2
2
2
2
2
2
2
2
3
4
2
3
2
1
4
3
2
3
2
3
1
3
2
4
4
2
3
2
2
3
2
1
3
3
3
1
1
3
4
4
3
3
3
3
2
3
1
3
D-5
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Rank
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
Catalog
Unit No.
11140202
05070201
05030204
10270207
05020005
05120101
10240008
10240006
05090203
03040205
16050101
03050201
16050102
08050001
05140202
12010004
08090201
05030201
08030201
08080202
04120103
08010100
04010302
07080202
05140206
04030201
05120113
03060101
12010005
03060106
05110003
11140203
11140304
Catalog Unit
Name
MIDDLE RED-COUSHATTA
TUG. KENTUCKY VIRGIN
HOCKING. OHIO.
LOWER LITTLE BLUE . K
LOWER MONONGAHELA. P
UPPER WABASH. INDIAN
BIG NEMAHA. KANSAS N
LITTLE NEMAHA. NEBRA
MIDDLE OHIO-LAUGHERY
BLACK. SOUTH CAROLIN
LAKE TAHOE. CALIFORN
COOPER. SOUTH CAROLI
TRUCKEE. CALIFORNIA
BOEUF. ARKANSAS LOUI
HIGHLAND-PIGEON. IND
TOLEDO BEND RESERVOI
LIBERTY BAYOU-TCHEFU
LITTLE MUSKINGUM-MID
LITTLE TALLAHATCHIE.
MERMENTAU. LOUISIANA
BUFFALO-EIGHTEENMILE
LOWER MISSISSIPPI -ME
BAD-MONTREAL. MICHIG
SHELL ROCK. IOWA MIN
LOWER OHIO. ILLINOIS
UPPER FOX. WISCONSIN
LOWER WABASH . ILLINO
SENECA. NORTH CAROLI
LOWER SABINE . LOUISI
MIDDLE SAVANNAH. GEO
MIDDLE GREEN. KENTUC
LOGGY BAYOU. ARKANSA
CROSS BAYOU. ARKANSA
Mean
Before
CWA
7.
6.
4.
7.
7
6.
7
6.
5.
3.
7
6.
7
4,
5,
4
6.
7.
4.
2.
1.
5.
7.
8.
5.
6.
4.
7.
6.
8.
5.
5
6.
.120
.173
860
.330
.937
.450
.340
.820
.400
.950
.190
.045
.780
.347
.140
.960
.400
.100
.810
.260
.880
.800
.460
.100
.800
.760
.990
.920
.580
.210
.850
.300
.640
Mean
After
CWA
6.050
5.100
3.717
6.070
6.661
5.173
6.060
5.520
4.043
2.581
5.818
4.566
6.264
2.629
3.388
3.200
4.620
5.301
3.006
0.430
0.000
3.830
5.463
6.080
3.642
4.400
2.550
5.416
3.836
4.957
1.942
1.006
1.253
# Stations
Differ-
ence
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1
-1.
-1
-1
-1.
-1
-1
-1
— P
-2.
-2
-2.
-2.
-2
-3.
-3
-4
-5
.070
.073
.143
.260
.275
.277
.280
.300
.357
.369
.372
.479
.516
.717
.753
.760
.780
.799
.804
.830
.880
.970
.997
.020
.158
.360
.440
.504
.744
.253
.908
.294
.387
Before
cm
2
3
1
1
3
3
1
1
1
2
1
1
3
3
1
1
2
1
2
2
2
1
2
1
1
1
1
1
2
1
6
2
2
After
CrtA
2
1
4
2
31
8
1
1
6
17
4
7
13
14
4
1
2
10
5
2
1
1
4
1
5
1
3
21
6
13
4
5
3
# Q years
Before
CWA
4
3
4
1
4
3
2
2
2
2
2
2
3
4
5
4
2
4
3
1
3
3
3
2
3
2
4
1
3
1
5
3
4
After
CWA
3
2
2
1
1
1
1
1
2
2
4
3
4
4
1
4
2
3
4
1
3
3
3
3
4
2
1
4
1
3
4
3
2
D-6
-------
Appendix D: Before and After CWA Changes in DO and BOD5 at the Catalog Unit Level
Table
Rank
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
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
D-2. Before and
Catalog
Unit No.
03050109
03050103
10270205
10190006
05120201
03170008
04100002
05050008
04110001
04040002
05120104
07040006
02040204
07010207
07040001
07010206
04030104
04080206
04090005
02070007
05070204
05120103
05090202
05030103
03050208
08040301
08020401
16050102
04030204
05070201
05010009
10190007
05050006
07070002
05140202
02040203
02040202
05120101
05050002
05090203
11110207
07030005
03160203
03040202
07080202
07010203
03050205
03140305
07020007
03100204
08040202
03080103
07020012
04030101
16020204
11110104
03050105
07060005
17080001
09030004
09020301
04110002
17090003
03040205
04080201
05090101
05140101
03160106
05140206
After CWA Changes in
Catalog Unit
Name
SALUDA. SOUTH CAROLI
LOWER CATAWBA. NORTH
LOWER BIG BLUE. KANS
BIG THOMPSON. COLORA
UPPER WHITE. INDIANA
ESCATAWPA. ALABAMA M
RAISIN. MICHIGAN OKI
LOWER KANAWHA. WEST
BLACK-ROCKY. OHIO.
PIKE-ROOT. ILLINOIS
EEL. INDIANA.
LACROSSE-PINE. MINN
DELAWARE BAY. NEW JE
RUM. MINNESOTA.
RUSH-VERMILLION. MIN
TWIN CITIES . MINNESO
OCONTO. WISCONSIN.
SAGINAW. MICHIGAN.
HURON. MICHIGAN.
SHENANDOAH. VIRGINIA
BIG SANDY. KENTUCKY
MISSISSINEWA. INDIAN
LITTLE MIAMI . OHIO .
MAHONING. OHIO PENNS
BROAD-ST. HELENA. SO
LOWER RED. LOUISIANA
LOWER ARKANSAS . ARKA
TRUCKEE. CALIFORNIA
LOWER FOX. WISCONSIN
TUG. KENTUCKY VIRGIN
LOWER ALLEGHENY . PEN
CACHE LA POUDRE. COL
UPPER KANAWHA. WEST
LAKE DUBAY. WISCONSI
HIGHLAND-PIGEON. IND
SCHUYLKILL. PENNSYLV
LOWER DELAWARE. NEW
UPPER WABASH. INDIAN
MIDDLE NEW. VIRGINIA
MIDDLE OHIO-LAUGHERY
LOWER ARKANSAS-MAUME
LOWER ST. CROIX. MIN
LOWER TAMBIGBEE . ALA
LYNCHES . NORTH CAROL
SHELL ROCK. IOWA MIN
CLEARWATER-ELK. MINN
EDISTO . SOUTH CAROLI
ESCAMBIA. ALABAMA FL
MIDDLE MINNESOTA. MI
ALAFIA. FLORIDA.
LOWER OUACHITA-BAYOU
LOWER ST. JOHNS. FLO
LOWER MINNESOTA. MIN
MANITOWDC-SHEBOYGAN .
JORDAN. UTAH.
ROBERT S . KERR RESER
UPPER BROAD. NORTH C
APPLE-PLUM. ILLINOIS
LOWER COLUMBIA-SANDY
UPPER RAINY. MINNESO
SANDHILL-WILSON. MIN
CUYAHOGA. OHIO.
UPPER WILLAMETTE . OR
BLACK. SOUTH CAROLIN
TITTABAWASSEE. MICHI
RACCOON-SYMMES . OHIO
SILVER-LITTLE KENTUC
MIDDLE TOMBIGBEE-LUB
LOWER OHIO. ILLINOIS
90th Percentile
Mean
Before
CWA
64.105
48.153
43.400
36.303
34.823
21.990
21.440
13.663
16.406
12.400
8.300
9.400
5.200
9.000
6.779
10.143
6.860
10.876
9.780
6.490
5.100
8.240
7.500
9.600
7.900
6.620
6.610
5.500
9.660
4.693
4.470
8.192
2.450
8.840
4.970
5.840
5.792
7.763
7.550
6.100
5.300
4.238
2.969
5.781
16.890
5.000
3.916
2.935
7.733
2.693
4.500
3.340
8.272
5.550
16.843
6.300
4.200
5.896
1.480
1.560
4.955
8.400
2.345
3.130
4.000
1.600
2.880
2.520
1.990
BOD6 (mg/L)
Mean
After
CWA
4.848
8.831
6.510
5.700
6.869
1.880
6.240
2.550
8.000
6.100
2.100
3.745
0.038
4.340
2.160
5.580
2.450
6.560
5.500
2.500
1.180
4.337
3.605
5.740
4.122
3.210
3.230
2.317
6.543
1.612
1.780
5.700
0.000
6.430
2.660
3.587
3.580
5.562
5.350
3.945
3.366
2.340
1.251
4.326
15.500
3.650
2.720
2.050
6.850
1.810
3.773
2.642
7.810
5.290
16.594
6.060
3.980
5.700
1.300
1.390
4.830
8.300
2.283
3.208
4.100
1.700
3.000
2.700
2.230
at the Catalog Unit
Level
# Stations
Differ-
ence
-59.257
-39.322
-36.890
-30.603
-27.955
-20.110
-15.200
-11.113
-8.406
-6.300
-6.200
-5.655
-5.162
-4.660
-4.619
-4.563
-4.410
-4.316
-4.280
-3.990
-3.920
-3.903
-3.895
-3.860
-3.778
-3.410
-3.380
-3.183
-3.117
-3.081
-2.690
-2.492
-2.450
-2.410
-2.310
-2.253
-2.211
-2.201
-2.200
-2.155
-1.934
-1.898
-1.718
-1.456
-1.390
-1.350
-1.196
-0.885
-0.883
-0.883
-0.727
-0.698
-0.462
-0.260
-0.249
-0.240
-0.220
-0.196
-0.180
-0.170
-0.125
-0.100
-0.062
0.078
0.100
0.100
0.120
0.180
0.240
Before
CWA
4
8
1
8
19
6
1
3
5
1
1
1
1
1
6
21
1
14
2
1
1
1
1
6
1
1
1
1
1
3
1
10
2
1
1
1
16
3
2
1
1
5
8
13
1
1
5
2
5
3
1
1
16
3
7
1
1
5
1
1
2
2
6
2
1
1
1
1
1
# Q years
After Before After
CWA
58
15
2
2
14
1
1
1
2
1
1
2
8
1
1
5
2
2
2
2
1
3
2
1
11
1
2
7
3
1
1
2
1
3
2
3
19
5
2
2
7
1
9
17
1
2
6
1
3
2
3
26
2
2
25
2
26
4
1
4
2
6
6
16
2
2
2
1
1
CWA
1
2
2
2
3
2
4
3
5
2
3
3
5
3
3
3
1
4
4
5
3
3
3
5
1
4
2
3
2
3
4
2
3
2
5
4
4
3
3
2
2
3
2
2
2
3
1
2
3
2
4
1
2
1
2
4
1
2
2
1
2
5
1
2
3
4
2
2
3
CWA
4
2
1
1
1
2
1
2
1
1
1
2
3
3
2
3
3
1
1
2
4
1
1
I
2
I
4
4
3
2
1
1
2
3
1
1
1
1
2
2
4
3
2
3
3
3
3
2
3
4
4
4
3
1
1
3
3
2
1
2
3
1
1
2
1
3
1
4
4
D-7
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Rank
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
Catalog
Unit No.
04090001
05030101
04030108
03050201
06020001
03060101
03040204
05120113
02040201
05030202
02070010
05110003
02070004
02070008
05050001
07080209
03040201
07040002
05120111
02050306
03050207
05090201
07070003
10240011
10300101
05120202
10200203
07120003
Catalog Unit
Name
ST. CLAIR. MICHIGAN.
UPPER OHIO . OHIO PEN
MENOMINEE. MICHIGAN
COOPER. SOUTH CAROLI
MIDDLE TENNESSEE-CHI
SENECA. NORTH CAROLI
LITTLE PEE DEE. NORT
LOWER WABASH. ILLINO
CROSSWICKS-NESHAMINY
UPPER OHIO-SHADE . OH
MIDDLE POTOMAC-ANACO
MIDDLE GREEN. KENTUC
CONOCOCHEAGUE-OPEQUO
MIDDLE POTOMAC-CATOC
UPPER NEW. NORTH CAR
LOWER IOWA. IOWA.
LOWER PEE DEE NORTH
CANNON. MINNESOTA.
MIDDLE WABASH- BUSSER
LOWER SUSQUEHANNA . M
SALKEHATCHIE . SOUTH
OHIO BRUSH-WHITEOAK.
CASTLE ROCK WISCONS
INDEPENDENCE-SUGAR.
LOWER MISSOURI-CROOK
LOWER WHITE. INDIANA
SALT. NEBRASKA.
CHICAGO ILLINOIS IN
Mean
Before
CWA
3
3
2
2
1
3.
3.
5
4
1.
3.
2.
2.
3.
2.
6
3.
2.
5
2
4.
1.
3
3
6
7.
9
7
.707
.200
.760
.540
.692
.720
.487
.540
.527
.900
.880
236
.200
.580
073
550
979
410
970
980
475
900
000
000
500
000
900
922
Mean
After
cm
4
3
3
3
2
4
5
7
6
3
5
4
4
5
4
9.
6
5
9
6.
9.
6
8.
8.
12.
13 .
20
19.
.000
.700
.420
.239
.455
.739
.054
.170
.215
.640
.762
.154
.200
.607
.251
.000
731
255
640
.800
.056
810
470
750
278
293
000
000
# Stations
Differ-
ence
0.293
0.500
0.660
0.699
0.763
1.019
1.566
1.630
1.688
1.740
1.882
1.918
2.000
2.027
2.178
2.450
2.753
2.845
3.670
3 820
4.581
4.910
5 470
5.750
5 .778
6.293
10 100
11.078
Before After
CW& CWA
6
1
1
1
11
1
7
1
7
1
1
5
1
1
3
2
18
1
1
1
2
1
1
1
1
1
2
13
1
2
1
6
6
14
11
1
4
2
38
2
2
14
11
1
36
2
1
2
5
2
3
1
5
3
1
6
# Q years
Before
CWA
4
5
1
2
1
1
2
4
4
4
5
5
5
5
1
2
2
2
3
4
1
3
2
3
3
3
3
2
After
CWA
1
1
3
3
3
4
3
1
1
3
2
4
2
2
2
2
3
3
1
1
3
3
3
2
1
1
1
1
D-8
-------
Appendix E
Before and After CWA Changes
in 10th Percentile Dissolved
Oxygen at the RF1 Level
Table
E-1 Before and After CWA Changes in 10th Percentile Dissolved Oxygen at the RF1 Level
E-3
E-1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
E-2
-------
Appendix E: Before and After CWA Changes in DO at the Rf1 Reach Level
Table D-1 . Before and
Rank
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
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
Rfl
Unit No.
10170203037
04100002001
04110002001
05030103007
07070002034
05120201004
05080002008
07120004018
07090001004
05020006031
04040002005
02040201011
04030101012
03170006007
06010102004
08030203006
04040003001
04030104002
08030205018
05050008006
04120102002
03050109053
07120004002
05120201013
03050103037
03170006025
18090208001
06010104007
04130003001
18020103014
02040202045
07010206001
07140201014
07120007006
02040205007
03050109068
02040202035
03180004009
05080001019
05090101004
07120003006
03100204003
02040202043
05120201011
04100009001
03100204001
02040202027
08030204015
07120004010
02040201004
18070203005
05090202001
07130001005
02040202085
01080205033
04100009005
07140201013
06010205001
03040201049
07060005028
02040202030
06010105021
07120006001
06020001020
04110001004
02040203002
05090201001
04040001010
After CWA Changes in 10th Percentile
Rfl
Name
BIG SIOUX R
RIVER RAISIN
CUYAHOGA R
MAHONING R
WISCONSIN R
WHITE R
GREAT MIAMI R
DU PAGE R, E BR
ROCK R
CASSELMAN R
ROOT R
NESHAMINY R
MANITOWOC R
PASCAGOULA R
HOLSTON R, S FK
ENID L
MILWAUKEE R
OCONTO R
GRENADA L
KANAWHA R
CATTARAUGUS CR
REEDY R
DBS PLAINS R
WHITE R
CATAWBA R
ESCATAWPA R
MOJAVE R
CHEROKEE L
GENESEE R
SACRAMENTO R
DELAWARE R
MISSISSIPPI R
KASKASKIA R
FOX R
BRANDYWINE CR, E BR
SALADA R
DELAWARE R
PEARL R
GREAT MIAMI R
OHIO R
LITTLE CALUMET R
ALAFIA R
DELAWARE R
WHITE R
MAUMEE R
ALAFIA R
DELAWARE R
COLDWATER R
DBS PLAINS R
DELAWARE R
SANTA ANA R
LITTLE MIAMI R
ILLINOIS R
DELAWARE R
CONNECTICUT R
MAUMEE R
KASKASKIA R
CLINCH R
JEFFRIES CR
MISSISSIPPI R
DELAWARE R
FRENCH BROAD R
FOX R
TENNESSEE R
BLACK R
WASSAHICKON CR
OHIO R
*B
Mean
Before
CWA
0.0000
1.6000
0.2950
1.0900
0.8800
0.6900
0.2000
0.5750
2.7600
2.9600
0.9400
2.6000
5.9500
0.0000
1.6000
0.0000
2.1800
0.5000
0.0000
0.0000
3.3000
1.9500
1.7620
2.2267
1.6780
0.0000
4.0200
0.1570
1.0425
5.9200
1.2000
2.5246
2.8933
4.4000
4.6000
0.5200
0.7000
2.0000
3.5000
3.2000
0.0000
2.7400
1.6000
3.3800
0.9835
2.4550
0.2000
0.0000
0.3000
2.8800
4.1400
4.0050
3.1900
0.4000
4.3000
4.0690
2.7400
1.6140
2.4400
3.3450
0.5000
4.1000
3.6600
3.2200
1.3775
3.8300
4.4000
0.5700
Dissolved Oxygen (mg/L) at the
Mean
After
CWA
7.2200
8.3400
6.4967
7.1600
6.8400
6.4240
5.8600
5.9200
8.0500
8.0000
5.9400
7.5600
10.9000
4.9200
6.4800
4.8673
6.9567
5.2000
4.6160
4.5667
7.6000
6.2270
6.0000
6.3750
5.8000
4.0983
7.9767
4.1007
4.7100
9.5500
4.7000
5.9924
6.2000
7.6800
7.7800
3.6925
3.8600
5.0000
6.4800
6.1600
2.9214
5.6000
4.4500
6.2200
3.8000
5.2600
3.0000
2.7990
3.0600
5.6300
6.8500
6.6800
5.8500
3.0300
6.8980
6.6660
5.3367
4.1965
5.0100
5.8900
3.0000
6.6000
6.1591
5.7067
3.8400
6.2750
6.8400
3.0056
RF1 Level
# Stations
Differ-
ence
7.2200
6.7400
6.2017
6.0700
5.9600
5.7340
5.6600
5.3450
5.2900
5.0400
5.0000
4.9600
4.9500
4.9200
4.8800
4.8673
4.7767
4.7000
4.6160
4.5667
4.3000
4.2770
4.2380
4.1483
4.1220
4.0983
3.9567
3.9437
3.6675
3.6300
3.5000
3.4678
3.3067
3.2800
3.1800
3.1725
3.1600
3.0000
2.9800
2.9600
2.9214
2.8600
2.8500
2.8400
2.8165
2.8050
2.8000
2.7990
2.7600
2.7500
2.7100
2.6750
2.6600
2.6300
2.5980
2.5970
2.5967
2.5825
2.5700
2.5450
2.5000
2.5000
2.4991
2.4867
2.4625
2.4450
2.4400
2.4356
Before
cm
1
2
2
1
1
5
1
4
1
1
1
1
1
1
1
1
2
1
1
2
1
4
2
3
5
1
2
1
4
1
2
13
3
1
1
1
1
2
1
1
1
2
1
3
4
2
1
1
3
3
2
2
2
1
1
3
2
1
2
4
2
1
1
2
4
1
1
2
After
CWA
1
2
24
1
1
1
1
3
1
1
1
1
1
7
2
3
3
1
4
3
2
10
1
2
1
6
3
3
2
2
1
26
2
4
1
4
2
1
1
1
7
1
1
1
2
1
1
1
4
1
2
1
2
1
1
5
3
2
2
1
3
1
11
3
2
2
1
5
E-3
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Rank
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
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
137
138
139
140
141
142
143
144
145
146
147
148
149
Rfl
Unit No.
03180004027
07130006003
03040201045
14010005007
03010106018
03170001001
06010207003
09020301004
Q7140106002
07120005013
05030103001
07040001001
11070207018
07120004017
03050101086
07040001012
05120202031
05140101002
05030101014
07090004004
03050208037
07120004019
07120004007
08020401001
05080001001
02040202048
05030203050
07130001025
17110013003
02040201002
03050103013
06020001030
17080005007
17110013004
07120004012
07140201004
17090003063
04080204005
07090006003
06010108010
05140202016
07130001026
02070007003
04140203001
06010102018
17080005002
04030101020
10190006002
07030005018
11110207005
07120005001
04030101008
03040202022
05020003026
03040204015
18040005002
18080003022
02050306013
03040201038
03040201005
03010106001
05120114001
05010009001
05020003016
11140208006
03180005003
05020002007
05050002030
07070003013
08080203011
10190007003
07020012013
03140305004
07130003018
03100101010
17110011002
05120103010
05130108022
03170008001
10200203040
03040202014
Rfl
Name
BOGUE LUSA CR
SANGAMON R
BIG BLACK CR
COLORADO R
ROANOKE R
OKATIBBEE CR
CLINCH R
RED R
BIG MUDDY R
ILLINOIS R
MAHONING R
MISSISSIPPI R
*A
DU PAGE R
CROWDERS CR
VERMILLION R
WHITE R
OHIO R
OHIO R
SUGAR R
SANDERS BR
DU PAGE R, W BR
CHICAGO SHIP CANAL
ARKANSAS R
MAD R
DELAWARE R
LITTLE KANAWHA R
ILLINOIS R
ELLIOT BAY
DELAWARE R
CANE CR
TENNESSEE R
COWLITZ R
DUWAMISH WATERWAY
DBS PLAINS R
L SHELBYVILLE
WILLAMETTE R
FLINT R
KISHWAUKEE R
NOLICHUCKY R
OHIO R
ILLINOIS R
SHENANDOAH R
OSWEGO R
S HOLSTON L
COWEMAN R
SHEBOYGAN R
THOMPSON R
ST CROIX R
ARKANSAS R
ILLINOIS R
E TWIN R
LITTLE LYNCHES R
MONONGAHELA R
LITTLE PEE DEE R
MOKELUMNE R
SUSAN R
SUSQUEHANNA R
BLACK CR
PEE DEE R
ROANOKE R
LITTLE WABASH R
ALLEGHENY R
MONONGAHELA R
SALINE BAYOU
BOGUE CHITO R
WEST FORK R
NEW R
CASTLE ROCK FLOWAGE
CALCASIEU R
CACHE LA POUDRE R
MINNESOTA R
ESCAMBIA R
ILLINOIS R
PEACE R
SNOHOMISH R
MISSISSINEWA R
CUMBERLAND R, CANEY
ESCATAWPA R
SALT CR
LYNCHES R
Mean
Before
cm
4
0
2
4
0
3
5
4
2
3.
1
3
1
4
1.
4
3.
3.
4
5.
1.
2.
0
5.
2
3
5.
4
4.
2 .
0
3.
8.
5
2.
5.
7
4
5.
5.
5
1.
5
4
3 .
5
4 .
5
5
6.
5
4.
4 .
5
4.
7 .
6
0
4.
4.
4
2
6.
6.
4
6
4.
5.
5.
4.
6
5.
5.
4
4
8.
5.
4
1
4.
5
.1333
0000
.1000
.8800
.3633
.3000
.2600
.1000
.2900
.9320
.9225
.9390
.6000
.0000
.9000
.2205
.4200
.4000
.5300
.9000
.9167
9333
0250
6500
8200
3100
1400
2700
3500
8400
0000
9000
1800
6940
1500
4000
5200
2350
0000
5800
1400
2000
2600
3000
7380
9900
5000
6500
7580
2000
2170
5800
6417
8100
6400
4800
8200
8800
5350
6133
6000
3400
0600
3000
1600
0000
8000
7000
0000
3200
2578
6690
1200
3920
1300
3600
8400
2000
5800
4000
5825
Mean
After
CWA
6
2
4
7
2
5
7
6
4
6
3
5
3
5
3
6
5
5
6
7
3
4
1
7.
4 .
5
6
5
5.
4
1
5.
9
7
3.
6.
8
5.
6.
7
6.
2 .
6
5.
5
7
5
6.
7
7
6.
5.
5
7 .
5.
8
8.
2.
5.
5
5
3 .
7 .
7.
5
7.
5
6
6
5.
7 .
6
6
5.
5
9.
6
5.
2
5 .
6.
.5600
.3875
.4500
.2200
.5700
.5000
.4390
.2600
.3988
.0400
.9200
.9000
.5000
.8620
.7600
.0800
.2700
.2500
.3760
.7000
.7033
7033
.7800
.3900
.5400
.0000
8250
.9000
.9600
.4200
.5800
.4717
.7300
2400
.6835
9100
9800
.6800
.4225
0000
.5400
.6000
6600
7000
1150
3400
8200
9620
0500
4900
4800
.8300
8850
0480
8600
TOOO
0400
0700
7100
7800
7600
5000
1850
4120
2400
0000
8000
7000
0000
3200
.2500
6600
1000
3650
0800
3000
7800
1100
4900
3007
4600
# Stations
Differ-
ence
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1.
1
1
1.
1
1
1.
1.
1
1.
1
1
1.
1.
1.
1
1.
1
1
1.
1.
1
1.
1
1
1
1.
1.
1
1.
1.
1
1
1.
1.
1
1
1.
1.
1.
1
1.
1.
1
1.
1.
1
0
0
0.
0.
0.
0
0.
0.
0
0
0.
.4267
.3875
.3500
.3400
.2067
.2000
.1790
.1600
.1088
.1080
.9975
.9610
.9000
.8620
.8600
.8595
.8500
.8500
.8460
.8000
.7866
7700
.7550
.7400
7200
6900
.6850
6300
6100
.5800
.5800
5717
.5500
5460
5335
5100
.4600
4450
4225
4200
4000
4000
4000
4000
3770
3500
3200
3120
2920
2900
2630
2500
2433
2380
2200
2200
2200
1900
1750
1667
1600
1600
1250
1120
0800
0000
0000
0000
0000
0000
9922
9910
9800
9730
9500
9400
9400
9100
9100
9007
8775
Before After
CWA CWA
3
1
1
1
3
2
2
2
1
1
4
2
1
2
1
2
1
1
1
1
3
3
1
2
1
2
1
1
2
2
1
1
1
5
1
1
3
2
1
1
1
1
1
1
1
2
1
3
2
1
2
1
3
1
2
1
1
1
2
3
1
1
1
1
1
2
1
1
1
2
9
1
2
2
1
2
1
1
3
1
2
1
4
1
1
1
1
2
1
8
2
1
2
1
5
2
1
1
1
5
1
3
9
2
2
1
2
4
2
1
1
1
11
2
3
2
2
1
1
2
1
1
1
2
1
2
1
1
5
1
2
3
1
2
3
1
1
1
1
1
1
1
2
14
1
1
1
1
2
1
1
1
1
1
2
1
1
1
1
8
9
1
E-4
-------
Appendix E: Before and After CWA Changes in DO at the Rf1 Reach Level
Rank
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
Rfl
Unit No.
05020002001
17060110001
17010305001
03040202012
07120004009
03040201008
18070203008
07120006007
05120113006
10190006001
07130002001
07020012001
17110019081
04110003008
03050202006
08040304014
08030206007
03040204018
17090003058
05030202005
17020011001
04080201001
05120201032
08090203007
17110007006
04110003005
08040304013
17020015001
03040204016
05120101004
04110004001
03160203006
07010207005
08040302001
03050103018
07010206002
05020003003
03050205015
04010302018
03040201039
08070205005
11110207011
04030108001
05050005005
07040007002
06030002052
18030012014
06030005051
03160203007
06010103019
03050103021
03050205021
04080206001
03050202011
10190007004
06020001032
06020001001
05120106002
07040001008
02070001001
17080005011
05020006024
03040202015
17090003009
09030004013
05020004001
05050001044
05120108018
10180009016
08030201005
02070010033
05020005030
03160203015
06020001033
03170008002
05070204034
05010006005
07030005003
08050001011
03050207015
04010302002
07050005019
08040301020
05120201007
Rfl
Name
WEST FORK R
SNAKE R
SPOKANE R
LYNCHES R
CHICAGO SHIP CANAL
PEE DEE R
SANTA ANA R
FOX R
WABASH R
THOMPSON R
VERMILION R
MINNESOTA R
*W
ASHTABULA R
ASHLEY R
LITTLE R
BLACK CR
LITTLE PEE DEE R
WILLAMETTE R
OHIO R
WENATCHEE R
TITTABABASSEE R
EAGLE CR
INTRACOASTAL WATERWA
SKAGIT R
CHAGRIN R
LITTLE R
CRAB CR
LITTLE PEE DEE R
WABASH R
GRAND R
TOMBIGBEE R
RUM R
CASTOR CR
CATAWBA R
MISSISSIPPI R
MONONGAHELA R
POLK SWAMP
MONTREAL R
BLACK CR
TANGIPAHOA R
ARKANSAS R
MENOMINEE R
GAULEY R
BLACK R
TENNESSEE R
KINGS R
WILSON L
TOMBIGBEE R
WATAUGA R
TWELVEMILE CR
EDISTO R
SAGINAW R
ASHLEY R
CACHE LA POUDRE R
TENNESSEE R
TENNESSEE R
TIPPECANOE R
MISSISSIPPI R
POTOMAC R, S BR
TOUTLE R
CASSELMAN R
LITTLE FORK CR
WILLAMETTE R
RAINY R
CHEAT R
NEW R
WABASH R
H PLATTE R
SARDIS L
POTOMAC R
DUNKARD CR
TOMBIGBEE R
TENNESSEE R
ESCATAWPA R
BIG SANDY R
ALLEGHENY R
ST CROIX R
BOEUF R
LEMON CR
WHITE R
CHIPPEWA R
RED R
WHITE R
Mean
Before
CWA
6
7
7.
5
0
5
3
5
4
6
3
4
8
5
3
3
5
4
7
5
9
6
4
4
9
5
3
6
3
6
5
5
5
3
4
4
5
3.
7
3
6
6
6
7
7.
5
7
4
6
6.
3
5
4
3
6.
4
4
6
5
6
8.
8.
6.
8.
7
6
6
6
7.
3 .
4.
7.
6
4
5
5.
7
5.
4.
3.
7.
5 .
5 .
5
7200
.1700
.2000
.1833
4460
7250
6267
.5300
.9900
.2400
7750
. 7316
.0429
.1517
.7200
2400
5200
.7300
.2700
7000
.3000
0350
.7600
.5500
4200
3350
.5200
.6800
4320
.3400
6650
6040
.8000
.4400
6725
4700
.5400
.3000
.8000
5450
2000
.5200
.4400
.0900
.4500
4790
2400
8000
.2400
.0950
7600
4000
8989
.6200
.7900
.4000
.6140
1350
5850
3000
.8000
.6100
.0933
.3600
2000
5033
6000
5000
0000
4200
3400
7100
8200
4400
3700
7200
2000
4125
1600
8050
1200
3400
4500
5271
Mean
After
CWA
7.5820
8 0300
8 0587
6 0100
1.2650
6.5400
4 4333
6.3343
5 7800
7.0000
4 .4750
5 4257
8 7200
5.7700
4.3300
3.8500
6.1100
5 3000
7.8400
6.2600
9 8600
6.5800
5 2967
5.0750
9.9350
5 8400
4 0250
7 1800
3 .9187
6.8050
6.120C
6 048C
6.2400
3.8700
5.1000
4 8606
5 9000
3 6500
8.1500
3.8888
6 5400
6 8600
6.7500
7.4000
7.7400
5.7500
7 5000
5 0500
6 4850
6.3333
3.9900
5 6200
5 1167
3 8350
6.9960
4.6000
4.8067
6 3000
5 7467
6 4500
8.9200
8.7200
6.1567
8.4000
7 2333
6 5300
6.5700
6.4700
6 9500
3 .3680
4.2520
7.6000
6 6950
4 .3000
5 2250
5.5500
7 0290
5.2200
3 9560
3.5950
6.8800
5 1000
5 2000
5 2750
# Stations
Differ-
ence
0.8620
0 8600
0 8587
0.8267
0.8190
0.8150
0 8066
0.8043
0 7900
0.7600
0.7000
0.6941
0 6771
0.6183
0.6100
0.6100
0 5900
0 5700
0.5700
0.5600
0 5600
0 5450
0.5367
0.5250
0.5150
0.5050
0 5050
0.5000
0.4867
0 .4650
0 4550
0 4440
0.4400
0.4300
0 4275
0 3906
0 3600
0.3500
0.3500
0 3438
0 3400
0.3400
0.3100
0.3100
0 2900
0 2710
0 2600
0 2500
0.2450
0 2383
0 2300
0 2200
0 2178
0 2150
0.2060
0.2000
0 1927
0 1650
0 1617
0 1500
0.1200
0.1100
0.0634
0.0400
0.0333
0 0267
-0 0300
-0.0300
-0.0500
-0.0520
-0.0880
-0.1100
-0.1250
-0 1400
-0.1450
-0 1700
-0.1710
-0.1925
-0.2040
-0.2100
-0.2400
-0.2400
-0.2500
-0 2521
Before After
CWA CWA
1
1
2
3
2
4
3
1
1
1
2
9
7
3
1
1
1
1
1
1
1
2
1
1
2
2
1
3
5
1
3
5
1
1
2
5
2
1
1
3
2
1
1
1
1
1
1
1
1
2
1
1
19
1
3
1
3
2
4
1
1
2
3
1
1
3
1
1
1
1
1
1
2
1
1
1
1
4
1
2
1
1
1
7
1
1
3
2
2
1
3
3
1
1
2
7
1
2
1
1
4
1
1
1
1
1
3
2
2
1
1
1
4
2
3
5
1
2
1
36
1
1
1
8
1
2
2
1
1
1
2
2
2
3
2
1
3
2
5
1
3
1
3
1
1
1
3
1
3
2
1
1
1
1
5
1
2
1
2
2
10
1
2
2
1
1
2
2
E-5
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Rank
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
Rfl
Unit No.
10190018001
05050006007
03050105019
06040006017
17110008007
06020001019
02080206006
05050007001
08080203008
03050202010
05120105009
07020007002
07080208002
05120101006
08090201013
05030204009
04090005001
05070102002
05120201009
05120201006
03050205016
03050201018
03060101024
03050109075
06010102009
08040202006
03040202024
05020001027
05120104001
08050002003
06030002001
03040201003
04030105002
03050103054
08050001024
12010005005
05020001001
03050101007
11140202005
05020006001
05070201010
05020005001
03160106031
05120101003
03050205009
08080203001
08050001026
10240006001
16050102006
05020004003
05030201007
07090005004
16050101004
05020003001
03050208004
08050003005
05120108005
05020005006
12010004010
05010006001
07120003002
05030203014
08080202035
08040202002
03040202004
03040205003
10270207005
03050101005
07090005006
07140204001
05120112010
08030201003
03060106055
05120111 001
17110013005
11140203012
03040201050
11140304013
Rfl
Name
S PLATTE R
KANAWHA R
BROAD R
TENNESSEE R
STILLAGUAMISH R
TENNESSEE R
JAMES R
ELK R
CALCASIEU R
ASHLEY R
WABASH R
MINNESOTA R
L MCBRIDE
WABASH R
TCHEFUNCTA R
HOCKING R
HURON R
GUYANDOTTE R
WHITE R
FALL CR
EDISTO R
COOPER RIVER W BR
GOLDEN CR
GEORGES CR
BOONE L
BAYOU DE LOUTRE
HANGING ROCK CR
TYGART VALLEY R
EEL R
BAYOU MACON
TENNESSEE R
CATFISH CR
PESHTIGO R
ROCKY CR
BAYOU LAFOURCHE
SABINE R
TYGART VALLEY R
CATAWBA R
RED R
YOUGHIOGHENY R
BIG SANDY R, TUG FK
MONONGAHELA R
TOMBIGBEE R
WABASH R
EDISTO R
CALCASIEU R
BAYOU BOEUF
LITTLE NEMAHA R
TRUCKEE R
CHEAT R
OHIO R
ROCK R
L TAHOE
MONONGAHELA R
ASHEPOO R
TENSAS R
WABASH R
MONONGAHELA R
TOLEDO BEND RES
ALLEGHENY R
CHICAGO SAN SHIP CA
LITTLE KANAWHA R
MERMENTAU R
OUACHITA R
LYNCHES R
BLACK R
LITTLE BLUE R
L WYLIE
ROCK R
KASKASKIA R
EMBARRAS R, N FK
LITTLE TALLAHATCHIE
SAVANNAH R
WABASH R
GREEN R
BAYOU DORCHEAT
JEFFRIES CR
*B
Mean
Before
CUR
7 0600
7.0500
6 7000
5.4000
8 6750
5.0460
6 1400
6 4000
6 0000
3 3200
6.8600
6 9480
3 2840
7 0000
6.4000
4.8600
5 0000
6. 6200
4 6700
5.9600
4.9000
6 0450
7 9200
7 5500
2.5300
1.5000
4 9800
7 2500
7 0000
3 7000
5.4940
2 4900
6 2400
2 9950
3.6800
6.5800
8 1000
4 8000
7 1200
8 1200
6.2500
7 6000
5 5200
6 0100
4 6000
3.4500
5.2000
6.8200
7 7050
7 0800
7 1000
7 0600
7.1900
7 6000
3 4000
3 1000
7 0000
8.5000
4.9600
8.8000
6 4122
5 3900
2 2600
3 7700
6.0400
4 7000
7 3300
7 3000
5 5000
4 1300
5.0800
6.2000
8 2100
5 1000
8 4200
5 3000
4 6200
6 6400
Mean
After
CWA
6 8000
6 7800
6.4200
5 1133
8 3600
4 7300
5 7930
6 0500
5.6000
2 9000
6 4350
6 5200
2.8525
6 5600
5 9600
4 3850
4 5000
6 1000
4 1400
5.4250
4 3500
5 4650
7.3400
6.9250
1 9000
0 8600
4 3067
6.5500
6 1300
2 8300
4 6000
1.5575
5.3000
2 .0087
2 6670
5 5400
7 0513
3 .7500
6.0500
7 0400
5 1000
6 4060
4.3000
4.7650
3 3350
2 1700
3 .9000
5 5200
6.3852
5.7500
5 7500
5 7000
5 8175
6.2260
1.9600
1.6400
5 4640
6 8383
3.2000
7 0150
4.6180
3 5800
0 3200
1 7900
4.0367
2.6890
5.3000
5.1025
3 1250
1 7150
2 6600
3 6400
5 6150
2 5000
5 6300
2 4300
0 4300
0 6300
# Stations
Differ-
ence
-0 2600
-0.2700
-0.2800
-0 2867
-0 3150
-0.3160
-0.3470
-0 3500
-0 4000
-0 4200
-0.4250
-0 4280
-0 4315
-0 4400
-0 4400
-0.4750
-0.5000
-0 5200
-0 5300
-0 5350
-0.5500
-0 5800
-0 5800
-0 6250
-0.6300
-0.6400
-0 6733
-0 7000
-0 8700
-0.8700
-0.8940
-0 9325
-0 9400
-0 9863
-1 0130
-1.0400
-1.0487
-1 0500
-1 0700
-1 0800
-1.1500
-1.1940
-1 2200
-1 2450
-1 2650
-1.2800
-1.3000
-1 3000
-1 3198
-1 3300
-1 3500
-1.3600
-1.3725
-1.3740
-1.4400
-1 4600
-1 5360
-1 6617
-1.7600
-1.7850
-1 7942
-1 8100
-1 9400
-1 9800
-2.0033
-2.0110
-2.0300
-2.1975
-2 3750
-2 4150
-2 .4200
-2 5600
-2 .5950
-2 .6000
-2 7900
-2 8700
-4 1900
-6 0100
Before
CWA
1
1
1
2
1
1
1
2
1
1
1
5
1
2
1
2
1
1
1
1
1
1
1
1
2
2
1
1
2
1
2
1
2
1
1
1
1
2
1
1
1
1
1
1
2
1
1
2
2
1
1
1
1
1
1
1
1
1
1
5
1
2
2
1
1
1
1
1
1
1
1
1
1
1
2
1
2
After
CWA
1
1
I
3
1
2
1
1
1
1
1
1
4
1
1
2
1
1
1
2
1
2
2
2
1
1
3
1
1
2
1
6
1
4
2
1
3
2
2
1
1
9
1
1
2
2
1
1
5
1
1
2
4
5
1
1
1
6
1
4
10
2
1
3
5
1
4
4
2
2
1
3
1
2
1
2
2
E-6
-------
Glossary
10th Percentile
90th Percentile
Activated sludge
Advanced primary treatment
Advanced secondary treatment
Advanced wastewater treatment
(AWT)
Aerobic
Algae
A low end statistic based on ranking a data set from the minimum to
the maximum value. The 10th percentile defines the value for which
10% of the ranked data set is less than the statistic and 90% of the
data set is greater than the statistic. Used in this study to define
"worst-case" conditions for evaluation of "before and after" trends of
dissolved oxygen.
A high end statistic based on ranking a data set from the minimum to
the maximum value. The 90th percentile defines the value for which
90% of the ranked data set is less the statistic and 10% of the data
set is greater than the statistic. Used in this study to define "worst-
case" conditions for evaluation of "before and after" trends of
BOD5.
A secondary wastewater treatment process that removes organic
matter by mixing air and recycled sludge bacteria with sewage to
promote decomposition.
Waste treatment process that incorporates primary sedimentation of
suspended solids with chemical addition and flocculation to increase
the overall removal of organic solids. Advanced primary treatment
typically achieves about 50% removal of suspended solids and BOD.
Biological or chemical treatment processes added to a secondary
treatment plant including a conventional activated sludge to increase
the removal of solids and BOD. Typical removal rates for advanced
secondary plants are on the order of 90% removal of solids and
BOD.
Wastewater treatment process that includes combinations of physical
and chemical operation units designed to remove nutrients, toxic
substances, or other pollutants. Advanced, or tertiary, treatment
processes treat effluent from secondary treatment facilities using
processes such as nutrient removal (nitrification, denitrification),
filtration, or carbon adsorption. Tertiary treatment plants typically
achieve about 95% removal of solids and BOD in addition to removal
of nutrients or other materials.
Environmental conditions characterized by the presence of dissolved
oxygen; used to describe biological or chemical processes that occur
in the presence of oxygen.
Any organisms of a group of chiefly aquatic microscopic nonvascular
plants; most algae have chlorophyll as the primary pigment for carbon
fixation. As primary producers, algae serve as the base of the aquatic
food web, providing food for zooplankton and fish resources. An
overabundance of algae in natural waters is known as eutrophication.
Glossary -1
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Algal bloom
Ambient water quality
Ammonia
Ammonia toxicity
Anadromous
Anaerobic
Anoxic
Anthropogenic
Assimilative capacity
Bacterial decomposition
Base flow
Benthic
Biochemical oxygen demand (BOD)
Rapidly occurring growth and accumulation of algae within a body of
water. It usually results from excessive nutrient loading and/or
sluggish circulation regime with a long residence time. Persistent and
frequent bloom can result in low oxygen conditions.
Natural concentration of water quality constituents prior to mixing of
either point or nonpoint source load of contaminants. Reference
ambient concentration is used to indicate the concentration of a
chemical that will not cause adverse impact to human health.
Inorganic form of nitrogen; product of hydrolysis of organic nitrogen
and denitrification. Ammonia is preferentially used by phytoplankton
over nitrate for uptake of inorganic nitrogen.
Under specific conditions of temperature and pH, the un-ionized
component of ammonia can be toxic to aquatic life. The un-ionized
component of ammonia increases with pH and temperature.
Characteristic of fish that live in the ocean but spawn in freshwater.
Example: Salmon and steelhead.
Environmental condition characterized by zero oxygen levels. De-
scribes biological and chemical processes that occur in the absence
ofoxygen.
Aquatic environmental conditions containing zero or little dissolved
oxygen. See also anaerobic.
Pertains to the [environmental] influence of human activities.
The amount of contaminant load (expressed as mass per unit time)
that can be discharged to a specific stream or river without exceeding
water quality standards or criteria. Assimilative capacity is used to
define the ability of a waterbody to naturally absorb and use waste
matter and organic materials without impairing water quality or
harming aquatic life.
Breakdown by oxidation, or decay, of organic matter by heterotrophic
bacteria. Bacteria use the organic carbon in organic matter as the
energy source for cell synthesis.
Sustained, low flow discharge rate in a stream derived from ground-
water discharge into the stream channel. During extended periods of
low precipitation, baseflow may account for most, or all, of the
streamflow.
Refers to material, especially sediment, at the bottom of an aquatic
ecosystem. It can be used to describe the organisms that live on, or
in, the bottom of a waterbody.
The amount of oxygen per unit volume of water required to bacteri-
ally or chemically oxidize (stabilize) the oxidizable matter in water.
Biochemical oxygen demand measurements are usually conducted
over specific time intervals (5,10,20,30 days). The term BOD5
generally refers to standard 5-day BOD test.
Glossary -2
-------
Glossary
Carbonaceous
Carbonaceous BOD
Chlorophyll
Coliform bacteria
Combined sewer overflows (CSOs)
Commercial water use
Concentration
Confluence
Constituent
Construction Grants Program
Consumptive use
Contamination
Conventional pollutants
Pertaining to or containing organic carbon derived from plant and
animal residues.
Biochemical oxygen demand accounted for by decomposition of
organic carbon derived from plant and animal residues.
A group of green photosynthetic pigments that occur primarily in the
chloroplast of plant cells. The amount of chlorophyll-a, a specific
pigment, is frequently used as a measure of algal biomass in natural
waters.
A group of bacteria that normally live within the intestines of mam-
mals, including humans. Coliform bacteria are used as an indicator of
the presence of sewage in natural waters.
A combined sewer carries both wastewater and stormwater runoff.
CSOs discharged to receiving water can result in contamination
problems that may prevent the attainment of water quality standards.
Water used for motels, hotels, restaurants, office buildings, and other
commercial operations.
Mass amount of a substance or material in a given unit volume of
solution. Usually measured in milligrams per liter (mg/1) or parts per
million (ppm).
The physical location where a lower order stream or river flows into
a higher order stream or river as a tributary. See mouth.
A chemical or biological substance in water, sediments, or biota that
can be measured by an analytical method (e.g., nitrate-N, organic
carbon, or chlorophyll).
Federal funding authorized by amendments (1956 through 1987) to
1948 Federal Water Pollution Control Act to provide technical
assistance and construction money to aid municipalities in building and
upgrading sewerage collection systems and municipal wastewater
treatment plants. After 1972 amendments, $61.1 billion (current year
dollars) in federal funding provided under Clean Water Act to
upgrade municipal wastewater facilities to a minimum of secondary
treatment.
That part of water withdrawn that is evaporated, transpired, or
incorporated into a manufactured product, or consumed by humans or
animals, or otherwise removed from the immediate waterbody
environment.
Act of polluting or making impure; any indication of chemical, sedi-
ment, or biological impurities.
As specified under the Clean Water Act, conventional contaminants
include suspended solids, coliform bacteria, biochemical oxygen
demand, pH, and oil and grease.
Glossary - 3
-------
Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Decay
Decomposition
Denitrification
Dilution
Discharge
Discharge permits (NPDES)
Dispersion
Dissolved oxygen (DO)
Diurnal
Domestic wastewater
Domestic water use
Drainage basin
Gradual decrease in the amount of a given substance in a given
system due to various loss/sink processes including chemical and
biological transformation, dissipation to other environmental media, or
deposition into storage areas.
Metabolic breakdown of organic materials; the by-products formation
releases energy and simple organics and inorganic compounds, (see
also respiration)
Describes the decomposition of ammonia compounds, nitrites, and
nitrates (by bacteria) that results in the eventual release of nitrogen
gas into the atmosphere.
Addition of a volume of less concentrated liquid (water) that results in
a decrease in the original concentration.
The volume of water that passes a given point within a given period
of time. It is an all-inclusive outflow term, describing a variety of
flows such as from a pipe to a stream, or from a stream to a lake or
ocean.
A permit issued by the U.S. EPA or a state regulatory agency that
sets specific limits on the type and amount of pollutants that a munici-
pality or industry can discharge to a receiving water; it also includes a
compliance schedule for achieving those limits. It is called the
NPDES because the permit process was established under the
National Pollutant Discharge Elimination System, under provisions of
the Federal Clean Water Act.
The turbulent mixing and spreading of chemical or biological constitu-
ents, including pollutants, in various directions from a point source, at
varying velocities depending on the differential instream flow charac-
teristics.
The amount of oxygen gas that is dissolved in water. It also refers to
a measure of the amount of oxygen available for biochemical activity
in water body, and as indicator of the quality of that water.
Actions or processes having a period or a cycle of approximately one
tidal-day or are completed within a 24-hour period and which recur
every 24 hours.
Also called sanitary wastewater, consists of wastewater discharged
from residences and from commercial, institutional, and similar
facilities.
Water used for household purposes such as drinking, food prepara-
tion, bathing, washing clothes and dishes, watering lawns and gar-
dens, flushing toilets etc. Also called residential water use.
A part of the land area enclosed by a topographic divide from which
direct surface runoff from precipitation normally drains by gravity into
a receiving water. Also referred to as watershed, river basin, or
hydrologicunit.
Glossary - 4
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Glossary
Dynamic model
Dynamic simulation
Ecosystem
Effluent
Enforcement conferences
Estuary
Eutrophication
Factor of Safety
Fecal coliform bacteria
Flocculation
Flushing characteristics
Frequency analysis
Freshwater
A mathematical formulation describing the physical behavior of a
system or a process and its temporal variability.
Modeling of the behavior of physical, chemical, and/or biological
phenomena and their variation over time.
An interactive system that includes the organisms of a natural
community association together with their abiotic physical, chemical,
and geochemical environment.
Municipal sewage or industrial liquid waste (untreated, partially
treated, or completely treated) that flows out of a treatment plant,
septic system, pipe, etc.
Joint State-Federal water pollution conferences convened by U.S.
Public Health Service under authority of 1956 amendments to the
1948 Federal Water Pollution Control Act. Federal regulatory author-
ity restricted to enforcement of water pollution problems only in
interstate waters because of the Commerce clause of the U.S.
Constitution. Fifty-one enforcement conferences were convened
from 1957-1972.
Brackish-water areas influenced by the ocean tides where the mouth
of the river meets the sea.
Enrichment of an aquatic ecosystem with nutrients (nitrogen,
phosphorusnitrates, phosphates) that accelerate biological productivity
(growth of algae, periphyton and macrophytes/weeds) and an unde-
sirable accumulation of plant algal biomass.
Coefficient used to account for uncertainties in representing, simulat-
ing, or designing a system.
Coliform bacteria that are present in the intestines or feces of warm-
blooded animals including humans. They are often used as indicators
of the sanitary quality of water. See Coliform bacteria.
The process by which suspended colloidal or very fine particles are
assembled into larger masses or flocules that eventually settle out of
suspension.
Measure of the displacement of water from a riverine or estuarine
system as controlled by the combined actions of freshwater inflow
and tidal mixing and exchange.
A numerical determination of the distribution of values for a param-
eter within a data set. See 10th percentile, median and 90th percen-
tile.
Water that contains less than 1000 mg/L of dissolved solids. Water
that contains more than 500 mg/L of dissolved solids is undesirable
for drinking water and many industrial uses.
Glossary - 5
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Gaging station
"Grey" literature
Hydrologic Accounting Unit
Hydrologic Catalog Unit
Hydrologic cycle
Hydrologic Region
Hydrologic Sub-Region
In situ
A specific location on a stream, river, canal, lake or reservoir where
systematic measurements of hydrologic data such as stage height and
streamflow are collected. The USGS maintains and operates a
network of stream gaging stations to collect hydrologic data for many
streams and rivers. Historical streamflow and stage height data is
available from the USGS streamflow database
(www.waterdata.usgs.gov/nwis-w). Earliest records are available
from the late 19th century for some rivers.
Unpublished technical reports and memoranda, data reports, or other
documents prepared by academic researchers, Federal, state or local
agencies or other institutions and organizations. Typically limited
distribution makes it difficult to obtain except from agency or institu-
tional sources.
Geographical sub-division of watersheds within each Hydrologic Sub-
Region. There are a total of 352 Accounting Units in the United
States with 334 Accounting Units located in the 48 states. Account-
ing Units are identified by a 6-digit code where the first 2-digits
identify the Hydrologic Sub-region as the larger hydrologic units.
Example: 070102 is the Accounting Unit for the Platte-Spunk basin of
the Upper Mississippi River basin.
Geographical sub-division of watersheds within each Hydrologic
Accounting Unit. There are a total of 2150 Catalog Units in the
United States with 2111 Catalog Units located in the 48 states.
Catalog Units are identified by an 8-digit code where the first 2-digits
identify the Hydrologic Accounting Unit. Example: 07010206 is the
Catalog Unit for the Twin Cities area of the Upper Mississippi River.
The representation of the cycle of water on earth based on all
hydrologic processes and the interactions of water between the
atmosphere, surface waters, polar ice, glaciers, and groundwater.
Largest geographical sub-division of the United States into a hierar-
chal succession of hydrologic units based on drainage area. There are
a total of 21 Hydrologic Regions in the United States with 18 Hydro-
logic Regions located within the 48 states. Hydrologic regions are
identified by a 2-digit numerical code from 01-21. Example: 07 is the
Hydrologic Region for the Upper Mississippi River basin.
Geographical sub-division of watersheds within each Hydrologic
Region. There are a total of 222 Sub-Regions in the United States
with 204 Sub-Regions located in the 48 states. Sub-regions are
identified by a 4-digit code with the first 2-digits used to identify the
larger Hydrologic Region. Example: 0701 is the Hydrologic Sub-
region for the Mississippi Headwaters of the Upper Mississippi River
basin.
Latin word for "in place"; in situ measurements consist of measure-
ment of component or processes in a full-scale system or a field
rather than in a laboratory.
Glossary - 6
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Glossary
Industrial water use
Influent
Inorganic
Loading, Load, Loading rate
Low-flow (7Q10)
Major river basin
Margin of Safety (MOS)
Mass balance
Mathematical model
Mean
Median (50th Percentile)
Milligrams per liter (mg/L)
Water used for industrial purposes such as fabricating, processing,
washing and cooling. Industries that use water include steel, chemical
and allied products, paper and allied products, mining and petroleum
refining.
Water volume flow rate or mass loading of a pollutant or other
constituent into a water body or wastewater treatment plant.
Pertaining to matter that is neither living nor immediately derived
from living matter.
The total amount of material (pollutants) entering the system from
one or multiple sources; measured as a rate in weight (mass) per unit
time.
Low-flow (7Q10) is the 7-day average low flow occurring once in 10
years; this probability-based statistic is used in determining stream
design flow conditions and for evaluating the water quality impact of
effluent discharge limits.
alternative terminology for Hydrologic Region.
A required component of the TMDL that accounts for the uncer-
tainty about the relationship between the pollutant load and the quality
of the receiving waterbody.
An equation that accounts for the flux of mass going into a defined
area and the flux of mass leaving the defined area. The flux in must
equal the flux out to achieve a mass balance.
A system of mathematical expressions that describe the spatial and
temporal distribution of water quality constituents resulting from fluid
transport and the one, or more, individual processes and interactions
within some prototype aquatic ecosystem. A mathematical water
quality model is used as the basis for waste load allocation evalua-
tions.
The numerical average of a set of observations; computed as the sum
of the observations divided by the number of observations in the data
set.
A middle statistic based on ranking a data set from the minimum to
the maximum value. The median value divides the data set into so
that one-half of the values are lower than the median and one-half of
the values are greater than the median. The median is also defined as
the 50th percentile value.
A unit of measurement expressing the concentration of a constituent
in solution as the weight (mass) of solute (1 milligram) per unit
volume (1 liter) of water; equivalent to 1 part per million (ppm) for a
water density ~1 g cm-3. 1 mg/L = 1000 ug/L; 1 g/L = 1000 mg/L.
Glossary - 7
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Waste/water Treatment
Million gallons per day (mgd)
Mineralization
Mixing characteristics
Most probable number (mpn)
Municipal wastewater inventory
N/P ratio
Natural waters
Needs Survey
Nitrate (NO3) and Nitrite (NO2)
Nitrification
Nitrifier organisms
Nitrobacter
Nitrogenous BOD (NBOD)
Nitrosomonas
Rate of water volume discharge representing a volume of 1 million
gallons of water passing across a given location in a time interval of 1
day. A flow rate of 1 mgd = 1.54723 cubic feet per second (cfs) =
0.04381 cubic meters per second (cms).
The transformation of organic matter into a mineral or an inorganic
compound.
Refers to the tendency for natural waters to blend; i.e. for dissolved
and particulate substances to disperse into adjacent waters.
Measure of concentration, or abundance, of total and fecal coliform
bacteria based on incubation results and a statistical interpretation of
the results.
US Public Health Service compilations of inventory of municipal
wastewater plants, population served and influent flow by different
categories of municipal wastewater treatment facilities. Inventories
compiled in 1950,1962 and 1968.
The ratio of nitrogen to phosphorus in an aquatic system. The ratio is
used as an indicator of the nutrient limiting conditions for algal
growth; also used as indicator for the analysis of trophic levels of
receiving waters.
Flowing waterbody within a physical system that has developed
without human intervention, in which natural processes continue to
take place; streams, rivers, lakes, bays, estuaries and coastal and
open ocean are examples of natural waters.
USEPA Clean Water Needs Surveys (CWNS) compiled from 1976
through 1996 at 2 to 4 year intervals. Needs Surveys document
inventory of wastewater plants, population served, influent flow and
effluent load of BODS and TSS by 6 different categories of municipal
wastewater treatment facilities. Information is compiled for existing
conditions (e.g., 1996) and 20-year projections (e.g., 2016).
Oxidized nitrogen species. Nitrate is the form of nitrogen used by
aquatic plants for photosynthesis.
Biologically mediated process of the oxidation of ammonium salts to
nitrites (via Nitrosomonas bacteria) and the further oxidation of nitrite
to nitrate via Nitrobacter bacteria.
Bacterial organisms that mediate the biochemical oxidative processes
ofnitrification.
Type of bacteria responsible for the conversion of nitrite to nitrate.
Refers to the biochemical oxygen demand associated with the
oxidation of ammonia to nitrite and nitrate.
Type of bacteria responsible for the oxidation of ammonia to the
intermediate product nitrite.
Glossary - 8
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Glossary
Nonpoint source
Numerical model
Nutrient
Organic matter
Organic nitrogen
Outfall
Oxidation
Oxygen demand
Oxygen depletion
Oxygen sag
Oxygen saturation
Parameters
Parts per million (ppm)
Pollution that is not released through pipes but rather originates from
multiple sources over a relatively large drainage area. Nonpoint
sources can be divided into source activities related to either land or
water use including failing septic tanks, improper animal-keeping
practices, forest practices, and urban and rural runoff from a drain-
age basin.
Models that approximate a solution of governing partial differential
equations which describe a natural process. The approximation uses
a numerical discretization of the space and time components of the
system or process.
A primary element necessary for the growth of living organisms.
Carbon dioxide, nitrogen, and phosphorus, for example, are required
nutrients for phytoplankton (algae) growth.
The organic fraction that includes plant and animal residue at various
stages of decomposition, cells and tissues of soil organisms, and
substances synthesized by the soil population. Commonly determined
as the amount of organic material contained in a soil or water sample.
Organic form of nitrogen bound to organic matter.
Location point where wastewater or stormwater flows from a
conduit, stream, or drainage ditch into natural waters.
The chemical union of oxygen with metals or organic compounds
accompanied by a removal of hydrogen or another atom. It is an
important factor for soil formation and permits the release of energy
from cellular fuels.
Measure of the dissolved oxygen used by a system (microorganisms)
and or chemical compounds in the oxidation of organic matter. See
also biochemical oxygen demand.
Deficit of dissolved oxygen in a natural waters system due to oxida-
tion of natural and anthropogenic organic matter.
Description of characteristic spatial trend of the concentration of
dissolved oxygen in a stream or river downstream of high loading rate
of oxygen-demanding materials from tributaries, municipal or indus-
trial wastewater dischargers, or urban stormwater and combined
sewer overflow systems.
The maximum amount of oxygen gas that can be dissolved in natural
waters by transfer of oxygen from the atmosphere across the air-
water interface. The concentration of oxygen saturation is greatly
influenced by water temperature, salinity or chlorides concentration
and elevation above mean sea level, and other water characteristics.
Constituents measured in water quality monitoring programs. Ex-
amples: dissolved oxygen, BOD5, TSS, water temperature.
Measure of concentration of 1 part solute to 1 million parts water (by
weight). See milligrams per liter.
Glossary - 9
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Parts per thousand (ppt)
Pathogens
Per-capita use
Phosphorus
Photosynthesis
Phytoplankton
Plankton
Point source
Pollutant
Pretreatment
Primary productivity
Measure of concentration of 1 part solute to 1000 parts water (by
weight). See milligrams per liter.
a microorganism capable of producing disease. Pathogens are of
great concern to protect human health relative to drinking water,
swimming beaches and shellfish beds.
The quantity of water used per person per day averaged over a time
interval of 1 day; expressed as gallons per capita per day (gpcd).
A measure of acidity indicated by the logarithm of the reciprocal of
the hydrogen ion concentration (activity) of a solution. pH values less
than 7 are acidic; values greater than 7 are basic; pH of 7 is neutral.
pH of natural waters typically ranges from -6-8.
A nutrient essential for plant growth that can play a key role in
stimulating the growth of aquatic plants in streams, rivers and lakes.
The biochemical synthesis of carbohydrate based organic compounds
from water and carbon dioxide using light energy in the presence of
chlorophyll. Photosynthesis occurs in all plants, including aquatic
organisms such as algae and macrophytes. Photosynthesis also
occurs in primitive bacteria such as blue-green algae.
A group of generally unicellular microscopic plants characterized by
passive drifting within the water column. See Algae.
Group of generally microscopic plants and animals passively floating,
drifting or swimming weakly. Plankton include the phytoplankton
(plants) and zooplankton (animals).
Pollutant loads discharged at a specific location from pipes, outfalls,
and conveyance channels from either municipal wastewater treat-
ment plants or industrial waste treatment facilities. Point sources can
also include pollutant loads contributed by urban stormwater systems
or tributaries to the main receiving water stream or river.
A contaminant in a concentration or amount that adversely alters the
physical, chemical, or biological properties of a natural environment.
The term include pathogens, toxic metals, carcinogens, oxygen
demanding substances, or other harmful substances.
The treatment of wastewater to remove or reduce contaminants prior
to discharge into another municipal treatment system or a receiving
water.
A measure of the rate at which new organic matter is formed and
accumulated through photosynthesis and chemosynthesis activity of
producer organisms (chiefly, green plants). The rate of primary
production is estimated by measuring the amount of oxygen released
(oxygen method) or the amount of carbon assimilated by the plant
(carbon method)
Glossary -10
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Glossary
Primary treatment plant
Publicly Owned Treatment Works
(POTW)
Public-supply withdrawals
Range
Raw sewage
Reach (of a river)
Reach File Version 1 (RF1)
Reach File Version 3
Reaction rate coefficient
Reaeration
Removal efficiency
Receiving waters
Residential water use
Wastewater treatment process where solids are removed from raw
sewage primarily by physical settling. The process typically removes
about 25-35% of solids and related organic matter (BOD5).
Municipal wastewater treatment plant owned and operated by a
public governmental entity such as a town or city.
Water withdrawn from surface water or groundwater by public or
private water suppliers for use within a community. Water is used for
domestic, commercial, industrial and public water uses such as fire
fighting.
Statistical measure expressing the difference between the minimum
and maximum values recorded for a given constituent in time and
space.
Untreated municipal sewage.
A linear or longitudinal section of a stream or river defined by the
upstream and downstream locations of lower stream order tributaries
flowing into a higher stream.
US EPA hydrologic database designed to define the downstream
hydraulic routing of a connecting network of streams, rivers, lakes
and reservoirs, bays and tidal waters. Version 1 of the Reach File
(Rfl) includes a network of 64,902 Rfl reaches that includes 632,552
miles of waterbodies in the 48 states. Rfl reaches are indexed using
an 11 -digit code.
US EPA hydrologic database that defines the downstream hydraulic
routing of a more complex connecting network of streams, rivers,
lakes and reservoirs, bays and tidal waters than the Rfl database.
Version 3 of the Reach File (Rf3) includes a network of 1,821,245
Rf3 reaches that includes about 3.5 million miles of waterbodies in
the 48 states. Rf3 reaches are indexed using a 17-digit code.
Coefficient describing the rate of transformation of a substance in an
environmental medium characterized by a set of physical, chemical,
and biological conditions such as temperature and dissolved oxygen
level.
The net flux of oxygen transferred occurring from the atmosphere to
a body of water with a free surface.
A measure of how much of a pollutant is removed from raw sewage
prior to discharge into a receiving water after completion of waste-
water treatment processes. Expressed as percentage calculated as
Removal % = [(influent - effluent) /(influent)] x 100.
Creeks, streams, rivers, lakes, estuaries, groundwater formations, or
other bodies of water into which surface water and/or treated or
untreated wastewater are discharged, either naturally or in man-made
systems.
See domestic water use.
Glossary -11
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Respiration
River basin
Rotating biological contactors (RBCs)
Salinity
SAV
Secchi depth
Secondary treatment plant
Sediment
Sediment oxygen demand (SOD)
Significance level
Stabilization pond
Standard Industrial Classification
(SIC) codes
Biochemical process by means of which cellular fuels are oxidized
with the aid of oxygen to permit the release of the energy required to
sustain life; during respiration oxygen is consumed and carbon dioxide
is released.
see watershed
A wastewater treatment process consisting of a series of closely
spaced rotating circular disks of polystyrene or polyvinyl chloride.
Attached biological growth is promoted on the surface of the disks.
The rotation of the disks allows contact with the wastewater and the
atmosphere to enhance oxygenation.
The total amount of dissolved salts, measured by weight as parts per
thousand (ppt). Salinity concentrations range from -0.5-1 ppt for tidal
fresh waters; ~20-25 ppt for estuarine waters; ~ 30 ppt for coastal
waters to ~35 ppt for the open ocean.
Submersed or submerged aquatic vegetation. SAV describes rooted
aquatic plants that grow in shallow clear water.
A measure of the light penetration into the water column. Light
penetration is influenced by turbidity.
Waste treatment process where oxygen-demanding organic materials
(BOD) are removed by bacterial oxidation of the waste to carbon
dioxide and water. Bacterial synthesis of wastewater is enhanced by
injection of oxygen.
Particulate organic and inorganic matter that accumulates in a loose,
unconsolidated form on the bottom of natural waters.
The solids discharged to a receiving water are partly organics, and
upon settling to the bottom, they decompose anaerobically as well as
aerobically, depending on conditions. The amount of oxygen con-
sumed in the sediment bed during aerobic decomposition of detrital
organic carbon deposited on the bottom of a waterbody; represents
another dissolved oxygen loss/sink for the waterbody.
A statistical measure of the certainty that can be associated with the
results of a statistical analysis.
Large earthen basins that are used for the treatment of wastewater
by natural processes involving the use of both algae and bacteria.
Four-digit codes established by the Office of Management and
Budget (OMB) to classify commercial and manufacturing establish-
ments by the principal type of activity. Example: 4952 = municipal
wastewater treatment plant.
Glossary -12
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Glossary
State Revolving Fund (SRF)
Station (monitoring)
Passed under the Amendments to the Clean Water Act (CWA) in
1987, the Clean Water State Revolving Fund (CWSRF) program
replaced the long-running federal Construction Grants program.
Under the CWSRF program, each state and Puerto Rico created
revolving loan funds to provide independent and permanent sources
of low-cost financing for a range of environmental water quality
projects. As payments are made on loans, funds are recycled to fund
additional water protection projects. While traditionally used to build
or improve wastewater treatment plants, loans are used increasingly
for agricultural, rural, and urban runoff control; wet weather flow
control, including storm water and sewer overflows; alternative
treatment technologies; small decentralized systems; brownfields
remediation; and estuary improvements projects.
Funds to establish SRF programs are provided through federal
government grants (83 percent of total capitalization) and state
matching funds (17 percent of total capitalization). To augment the
federal and state capitalization, states may use the assets of the fund
to support the issuance of bonds. At their option some states choose
to transfer some Construction Grant funds into their CWSRF.
From the beginning of capitalization in 1988 through 1999, federal
contributions to the CWSRF program grew to $ 16.1 billion. Additional
state match, state leveraged bonds, loan repayments and fund
earnings increased CWSRF assets to over $30 billion since 1988.
Specific location in a waterbody chosen to collect water samples for
the measurement of water quality constituents. Stations are identified
by an alphanumeric code identifying the agency source responsible
for the collection of the data and a unique identifier code designating
the location. Station measurements can be recorded from either
discrete grab samples or continuous automated data acquisition
systems. Station locations are typically sampled by state, federal or
local agencies at periodic intervals (e.g., weekly, monthly, annual
etc.) as part of a routine water quality monitoring program to track
trends. Station locations can also be sampled only for a period of time
needed to collect data for an intensive survey or a special monitoring
program.
Stoichiometric ratio
STORE!
Mass-balance-based ratio for nutrients, organic carbon, dry weight
and algae (e.g., nitrogen-to-carbon ratio).
U.S. Environmental Protection Agency (EPA) national water quality
database for STORage and RETrieval (STORET). Mainframe water
quality database that includes millions of data records of physical,
chemical, and biological data measured in waterbodies throughout the
United States.
Glossary -13
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
Storm runoff
Stream order
Streamflow
Surface waters
Suspended solids or load
Tertiary treatment
Total Kjeldahl Nitrogen (TKN)
Total Maximum Daily Load (TMDL)
Total coliform bacteria
Toxic substances
Transport of pollutants (in water)
Tributary
Rainfall that does not evaporate or infiltrate into the ground because
of impervious land surfaces or a soil infiltration rate lower than
rainfall intensity, but instead flows onto adjacent land or waterbodies
or is routed into a drain or sewer system.
A ranking, developed by Straher, of the relative size of streams and
rivers within a watershed based on the network of tributaries. The
smallest, headwater stream is classified as an Order 1 stream. The
stream formed by the confluence of two or more Order 1 streams is
classified as an Order 2 stream. In the United States, the Mississippi
River is an Order 10 river.
Discharge that occurs in a natural channel. Although the term
"discharge" can be applied to the flow of a canal, the word
"streamflow" uniquely describes the discharge in a surface stream
course. The term streamflow is more general than "runoff as
streamflow may be applied to discharge whether or not it is affected
by diversion or regulation.
Water that is present above the substrate or soil surface. Usually
refers to natural waterbodies such as streams, rivers, lakes and
impoundments, and estuaries and coastal ocean.
Organic and inorganic particles (solids/sediment) suspended in and
carried by a fluid (water). The suspension is governed by the upward
components of turbulence, currents, or colloidal suspension.
Waste treatment processes designed to remove or alter the forms of
nitrogen or phosphorus compounds contained in domestic sewage.
The sumtotal of organic and ammonia nitrogen in a sample, deter-
mined by the Kjeldahl method.
The sum of the individual wasteload allocations and load allocations.
A margin of safety is included with the two types of allocations so
that any additional loading, regardless of source, would not produce a
violation of water quality standards.
A particular group of bacteria that are used as indicators of possible
sewage pollution.
Those chemical substances, such as pesticides, plastics, heavy
metals, detergent, solvent, or any other material that are poisonous,
carcinogenic, or otherwise directly harmful to human health and biota
the environment.
Transport of pollutants in water involves two main process: (1)
advection, resulting from the flow of water, and (2) diffusion, or
transport due to turbulence mixing in the water.
A lower order stream compared to a receiving waterbody. "Tributary
to" indicates the largest stream into which the reported stream or
tributary flows.
Glossary -14
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Glossary
Trickling filter
Turbidity
Ultimate Biochemical Oxygen
Demand (UBOD or BOD0)
Urban drainage
Waste load allocation (WLA)
Wastewater
Wastewater treatment
Water pollution
Water quality
Water quality criteria (WQC)
Water quality standard (WQS)
Watershed
Zooplankton
A wastewater treatment process consisting of a bed of highly
permeable medium (e.g., gravel or stones) to which microorganisms
are attached and through which wastewater is percolated or trickled
over the biofilm that forms on the media.
Measure of the amount of suspended material in water.
Long term oxygen demand required to completely stabilize organic
carbon and ammonia in wastewater or natural waters; defined as the
sum of ultimate carbonaceous BOD and nitrogenous BOD.
Water derived from surface runoff or shallow groundwater discharge
from urban land use areas.
The portion of a receiving water's total maximum daily load that is
allocated to one of its existing or future point sources of pollution.
Usually refers to effluent from an industrial or municipal sewage
treatment plant. See also domestic wastewater.
Chemical, biological, and mechanical processes applied to an indus-
trial or municipal discharge or to any other sources of contaminated
water in order to remove, reduce, or neutralize contaminants prior to
discharge to a receiving water.
Any condition of a waterbody that reflects unacceptable water
quality or ecological conditions. Water pollution is usually the result of
discharges of waste material from human activities into a waterbody.
Numerical description of the biological, chemical, and physical
conditions of a water body. It is a measure of a water body to
support beneficial uses.
Water quality criteria include both numeric and narrative criteria.
Numeric criteria are scientifically derived ambient concentrations
developed by EPA or States for various pollutants of concern to
protect human health and aquatic life. Narrative criteria are state-
ments that describe the desired water quality goal.
A water quality standard is a law or regulation that consists of the
beneficial designated use or uses of a waterbody, the numeric and
narrative water quality criteria that are necessary to protect the use
or uses of that particular waterbody, and an antidegradation state-
ment.
See drainage basin.
Very small animals (protozoans, crustaceans, fish embryos, insect
larvae) that live in a waterbody and are moved passively by water
currents and wave action.
Glossary -15
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Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment
U.S. Environmental Protection Agency
Region 5, Library (Pf,. J2J)
Glossary -16
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A River Reborn
"Time has been good to the Potomac River—at least the
last 25 years have been . . . . A generation ago (1960s and
1970), when we had gone to the Potomac for thrills, the river
was ugly and almost frightening in its decay. The water was an
opaque red-brown sludge, smelly and foaming with unknown
chemical pollutants. The shore was littered with the rotting
carcasses of carp and with slime-covered tires, cans, glass and
other filth.
But as we sat talking this time, the water was clear—really
clear—as though we were in the countryside far from a big city.
We could see right to the sandy bottom. The shoreline was free of
debris, and the air smelled fresh.
Best of all were the birds. Mallards swooped overhead,
heading toward the water. Despite the season, some songbirds
still darted through the trees. And far out in the channel, close to
Virginia, a huge flock of birds circled round and round a cluster
of rocks. They seemed to be feeding out there (on what type of
freshwater creature?), and the sun glistened off their wings....
Who are the stewards of the Potomac? Who is responsible
for the amazing rebirth of a beautiful river? To all, I extend a
hearty thanks..."
—Letter to the editor of The Washington Post,
January 15, 1995 (Chase, 1995)
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