The National Ocean Service: Working for America’s Coasts

More information or access to data, products, and services can be obtained from our Web sites:

Special Projects Office

http://spo.nos.noaa.gov

National Centers for Coastal Ocean Science

http://www.nccos.noaa.gov

The National Ocean Service (NOS) approaches the 21st century with a clear vision–that our coasts and oceans

enjoy robust health, provide a rich bounty of resources, and are wisely managed to endure competing uses. As

the nation's principal advocate for coastal and ocean stewardship, the National Ocean Service develops the

national foundation for coastal and ocean science, management, response, restoration, and navigation. This

report, developed by the NOS Special Projects Office and the National Centers for Coastal Ocean Science, strengthens this foundation, helping to bridge the gap between science, management, and public policy.

The Special Projects Office works to increase the effectiveness of coastal management in the United States, thereby

ensuring continued economic prosperity and environmental well-being throughout the nation's coastal regions.

A main objective of the Special Projects Office is to provide expertise, products, and services that assist the NOS

in designing and implementing an effective program of coastal stewardship throughout the agency. This effort

includes exploring ways to leverage the agency's considerable expertise into a force that more directly supports

and influences the sound management and protection of coastal areas. Special Projects is in a unique position to

bridge the gap between NOS scientific efforts and coastal management policy issues.

The National Centers for Coastal Ocean Science (NCCOS) works to understand the ocean and coastal environment, and the influences of human activities, by conducting research, monitoring, and assessments of these

delicate and important areas. NCCOS activities include understanding and predicting impacts of pollution and

coastal development on sensitive habitats and resources; helping to protect coastal property and residents from

storms and other natural hazards; understanding the causes and consequences of harmful algal blooms, such as

red tides and toxic Pfiesteria piscicida; understanding how climate change may affect our lives; and determining

the complex factors that affect fish populations.

To receive copies of this report, contact:

Pam Rubin

NOS Special Projects Office

pam.rubin@noaa.gov

301-713-3000, ext. 121

1305 East-West Highway, 9th Floor

Silver Spring, MD 20910-3281

This report should be cited as: Bricker, S.B., C.G. Clement, D.E. Pirhalla, S.P. Orlando, and D.R.G. Farrow. 1999.

National Estuarine Eutrophication Assessment: Effects of Nutrient Enrichment in the Nation’s Estuaries. NOAA,

National Ocean Service, Special Projects Office and the National Centers for Coastal Ocean Science. Silver Spring,

MD: 71 pp.
National Estuarine Eutrophication Assessment

Effects of Nutrient Enrichment in the Nation’s Estuaries

Special Projects Office

and the

National Centers for Coastal Ocean Science

National Ocean Service

National Oceanic and Atmospheric Administration

1305 East-West Highway

Silver Spring, MD 20910

September 1999

 Suzanne B. Bricker, Christopher G. Clement, Douglas E. Pirhalla,

 S. Paul Orlando, Daniel R.G. Farrow

NAT OINALOCEANIC ANDATMOSPHERICADMINISTRATOIN

U.S.DEPARTMENT OFCOMMERCERichard Alexander U.S. Geological Survey

Walter Boynton University of Maryland

David Brock Texas Water Development Board

Darell Brown U.S. Environmental Protection Agency

David Chestnut South Carolina Department of Health and Environmental Control

David Flemer U.S. Environmental Protection Agency

Holly Greening Tampa Bay National Estuary Program

Thomas Malone University of Maryland

Gregory McMurray Oregon Department of Environmental Quality

Jan Newton Washington Department of Ecology

Jonathan Pennock University of Alabama/Dauphin Island Sea Lab

Andrew Robertson National Oceanic and Atmospheric Administration

Donald Stanley East Carolina University

J. Kevin Summers U.S. Environmental Protection Agency

Terry Whitledge University of Alaska

National Assessment Core Group

National Assessment Workshop Participants

Merryl Alber University of Georgia

Donald Boesch University of Maryland

Thomas Brosnan National Oceanic and Atmospheric Administration

Brian Cole U.S. Geological Survey

Elizabeth Cosper Cosper Environmental Services, Inc.

Christopher D’Elia State University of New York at Albany

Ernest Estevez Mote Marine Laboratory

Peggy Fong University of California

Fred Holland South Carolina Department of Wildlife and Marine Resources

Renee Karrh Maryland Department of Natural Resources

Jack Kelly U.S. Environmental Protection Agency

Peter Larsen Bigelow Laboratory for Ocean Science

Theodore Loder University of New Hampshire

Robert Magnien Maryland Department of Natural Resources

Michael Mallin University of North Carolina

Hank McKellar University of South Carolina

Gary Powell Texas Water Development Board

Randy Shuman Metropolitan King County, Washington

Richard Smith U.S. Geological Survey

Ronald ThomBattelle Marine Science Laboratory

David Tomasko Southwest Florida Water Management District

Richard Valigura National Oceanic and Atmospheric Administration

Peter Verity Skidaway Institute of Oceanography

Richard Wetzel Virginia Institute of Marine Science

We would like to thank all of the estuarine research scientists and coastal resource managers whose contributions of data, information, and expertise were the key to making this report possible (Appendix C). The Core

Group was instrumental in developing methods for aggregating the data and, along with the other participants

in the National Assessment Workshop, reviewed and analyzed the results and made recommendations for a

national-level response to eutrophication problems in the nation’s estuaries.

This report is the result of the dedication and cooperation of many individuals who remained committed during the long duration of the project. Special thanks go to Daniel J. Basta, Director of NOS Special Projects, for his

vision and unflagging support, and to Richard Alexander and Richard Smith of the U.S. Geological Survey for

use of their SPARROW model results prior to publication. We also thank our NOS colleagues Charles Alexander

and C. John Klein for technical advice; Alison Hammer, John Hayes, Percy Pacheco, and Scot Frew for invaluable support provided for the National Assessment Workshop; Denise Yver for designing the report cover; and

Pam Rubin for reviewing and editing the manuscript.

ii

Acknowledgments
Foreword..........................................................................................................................iv

Executive Summary ........................................................................................................ v

Eutrophication Diagram ............................................................................................... ix

Introduction ..................................................................................................................... 1

Estuarine Eutrophication: Background to the Problem....................................................... 1

The Nation’s First Comprehensive Estuarine Eutrophication Assessment ...................... 3

The National Report: A Challenge to Interpret the Data ..................................................... 3

Extending the Assessment: Toward a National Strategy ..................................................... 6

Organizing the Results: Seven Key Questions ...................................................................... 8

Using this Report and the Data ............................................................................................... 8

National Overview ......................................................................................................... 9

Eutrophic Conditions ................................................................................................................ 9

Completing the Picture ........................................................................................................... 13

Regional Summaries .................................................................................................... 19

North Atlantic .......................................................................................................................... 20

Middle Atlantic ........................................................................................................................ 24

South Atlantic........................................................................................................................... 28

Gulf of Mexico.......................................................................................................................... 32

Pacific ........................................................................................................................................ 36

Conclusions.................................................................................................................... 41

Toward A National Strategy ....................................................................................... 45

Data Sources .................................................................................................................. 47

Appendices

A. Methods ................................................................................................................... 49

B. Table of Results ......................................................................................................... 63

C. Participants............................................................................................................... 67

iii

Table of Contents
Nancy Foster, Ph.D.

Assistant Administrator for Ocean Services

 and Coastal Zone Management

National Ocean Service, NOAA

This report is the culmination of almost seven years of effort to assess comprehensively the scale, scope, and characteristics of nutrient enrichment and

eutrophic conditions in the nation’s estuaries. It provides the most comprehensive assessment of this issue ever assembled for our nation’s estuaries,

and the results represent a significant contribution to the development of a

national strategy to control nutrient enrichment problems affecting U.S. coastal

waters. With this information, we have the opportunity to make a real difference in the actions this nation takes to address this important issue.

These results provide a valuable context for a host of ongoing and planned

activities addressing estuarine eutrophication, including reauthorization of

the Coastal Zone Management Act, particularly section 6217; reauthorization

of the Clean Water Act; the states’ development of Unified Watershed Assessments and Watershed Restoration Priorities as part of the Clean Water Action

Plan; the Report on the Status of the Nation’s Ecosystems; the Committee on

Environment and Natural Resources Gulf of Mexico Hypoxia Study; and

NOAA’s National Dialogues on Coastal Stewardship.

As important as the results themselves is the process used to acquire this information. The approach explicitly recognized that much of what is known

about these problems resides within the knowledge and experience of experts

around the nation. Hence, a process was developed to systematically obtain

information from more than 300 experts on estuarine eutrophication. Those

interested in this innovative approach to information synthesis can review the

Appendices to learn more about these methods and how to apply them.

During the past year, the National Ocean Service (NOS) has undergone a reorganization, and is emerging with a new focus on coastal stewardship. One of

the new roles for NOS is as a catalyst to ensure that scientific results are targeted to providing solutions to environmental problems and to preserving

the nation’s coastal and ocean resources. This report is also an example of the

type of activity that is needed to better bridge the gap between scientists and

resource managers. I encourage you to use this work to stimulate further efforts to protect our natural resources.

iv

Foreword
Eutrophication is the accelerated production

of organic matter, particularly algae, in a water body. It is usually caused by an increase

in the amount of nutrients being discharged

to the water body. As a result of accelerated

algal production, a variety of impacts may

occur, including nuisance and toxic algal

blooms, depleted dissolved oxygen, and loss

of submerged aquatic vegetation. These impacts are interrelated and usually viewed as

having a negative effect on water quality and

ecosystem health. Eutrophication has been

recognized as a problem in freshwater systems for many years, but only in the past

three decades has concern grown about the

widespread occurrence of eutrophic conditions in estuarine systems. Due to the complexity of the phenomena and the lack of

consistent national data sets, the severity and

extent of the problem had never been adequately characterized at the national scale.

What are the severity and extent of

eutrophic conditions exhibited within

the estuaries of the United States?

To what extent are eutrophic conditions

in the nation’s estuaries caused by human activities?

To what extent do eutrophic conditions

impair the use of estuarine resources,

and what are the important impaired

uses?

Where should management efforts be

targeted to achieve the greatest benefit

toward remediation and protection from

degradation?

v

The National Assessment

This report presents the results of a National

Assessment Workshop held in August 1998

to address the problem of estuarine

eutrophication. The assessment was based

primarily on the results of the National Estuarine Eutrophication Survey, conducted

by NOAA from 1992 to 1997, but was

supplemented by information on nutrient

inputs, population projections, and land use

drawn from a variety of sources. It covers

138 estuaries, representing over 90 percent

of the estuarine surface area of the coterminous United States, plus the Mississippi

River Plume. The final assessment presented here was undertaken at the National

Assessment Workshop by a select group of

experts, all of whom participated in the

eutrophication survey. The Workshop was

structured around answering seven key

questions regarding the severity and extent

of eutrophication in the nation’s estuaries.

All results presented in this report were reviewed by the Workshop participants.

About Estuarine Eutrophication

To what extent can the severity and extent of eutrophic conditions be expected

to increase by the year 2020, given the

natural susceptibility of estuaries and the

potential for increasing nutrient inputs?

Which data gaps and research and monitoring needs are most critical in terms of

improving the ability to assess and respond to eutrophication symptoms?

How can the results of this assessment

be translated into a national strategy?

1.

2.

3.

4.

5.

6.

7.

Key Questions

Executive Summary
vi

Executive Summary

Eutrophication Severity and Extent

Human Influence on Eutrophication

High expressions of eutrophic conditions are exhibited in 44 estuaries, representing 40% of the

total estuarine surface area studied. An additional

40 estuaries exhibit moderate conditions. When

considered together, the estuaries with moderate

to high conditions represent 65% of estuarine surface area in the study.

High conditions occur in estuaries along all coasts,

but are most prevalent in estuaries along the Gulf

of Mexico and Middle Atlantic coasts.

82 estuaries, representing 67% of estuarine surface area, exhibit moderate to high expressions of

at least one of the following symptoms: depleted

dissolved oxygen, loss of submerged vegetation,

and nuisance/toxic algal blooms.

A high level of human influence is associated with

a majority (36) of the 44 estuaries with high

eutrophic conditions.

Only six (14%) of the 44 estuaries with high-level

eutrophic conditions have corresponding highlevel nitrogen inputs. An additional 22 of the 44

estuaries have moderate-level nitrogen inputs.

Of the 44 estuaries with high-level eutrophic conditions, more than half (25) exhibit a high susceptibility to retaining nutrients.

Human influence on the expression of eutrophic conditions is substantial.

Symptoms of eutrophication are prevalent in the nation’s estuaries.

Assessment Data: National Estuarine Eutrophication Survey

Description: rigorous multi-year effort to synthesize the best

available information about eutrophic conditions

Characteristics:

consistent and comparable national data set was produced

through survey of over 300 estuarine scientists and managers

includes spatial and temporal information about eutrophication symptoms, including chlorophyll a, macroalgae, epiphytes, dissolved oxygen, submerged aquatic vegetation,

and nuisance/toxic algae

survey data aggregated by estuary and final results reviewed by experts at the Assessment Workshop

collection, evaluation, and review of the survey data was most

rigorous of all evaluations in the National Assessment

•

•

•

•

Watershed monitoring data from the U.S. Geological Survey provided first-order estimates of nitrogen inputs.

U.S. Census Bureau population estimates and Department of Agriculture Agricultural Census data were used

as potential nutrient pressure indicators.

Estuarine susceptibility was determined using NOAA

data on freshwater inflow, tide, and estuarine geometry.

Characteristics: assessment based on data less rigorously

evaluated and reviewed than for eutrophic conditions

Description: provides estimates of human-related nutrient inputs, estuarine susceptibility, and human influence

Assessment Data:

•

•

•

1

2

Assessment Data: expert evaluations at Workshop

Description: Experts identified impaired uses they judged

to be related to estuarine eutrophic conditions.

Characteristics: Although the information is not supported

by a comprehensive national data set, it does provide a

rough insight into the extent of problems stemming from

eutrophic conditions.

69 estuaries were identified by workshop participants as having human-use impairments related

to eutrophication.

Compared to other impaired uses, commercial/

recreational fishing and shellfisheries were identified as impaired for human use in the greatest

number of estuaries, 43 and 46, respectively.

3 Impaired Uses of Estuaries

Impairments to estuarine resources, and fisheries in particular, are of great concern.

Key Findings
vii

Executive Summary

Eutrophic conditions will most likely worsen in

86 estuaries by the year 2020.

Of the 86 estuaries expected to worsen, 43 exhibit

only low to moderate eutrophic conditions.

The 10 estuaries that exhibit low eutrophic conditions and have high susceptibility are most at

risk of future degradation if human-related nutrient inputs increase.

The 23 estuaries with high expressions of eutrophic

conditions and high susceptibility are likely to require

greater management effort and longer response time

for results than those estuaries with low susceptibility. These estuaries represent approximately 10% of

the national estuarine surface area.

There are 10 estuaries that have low eutrophic conditions and high susceptibility; accordingly, they should

be priorities for preventive management. These estuaries represent approximately 3% of the national estuarine surface area.

All of the typical point and nonpoint pollution sources

were identified at the Workshop as important to target in order to manage nutrient problems. However,

there are some important regional differences in nutrient sources, such as combined sewer overflows in

the North Atlantic.

Potential Management Concerns

Management requirements are dependent on eutrophic conditions and susceptibility.

4

Assessment Data: NOAA susceptibility and Eutrophication Survey data plus expert evaluations at Workshop

Description: In addition to evaluating eutrophic conditions and susceptibility (see numbers 1 and 2), experts

identified pollution sources important for managing

nutrient inputs in each watershed.

Characteristics: Although the pollutant source information is not based on a comprehensive national data set,

the expert evaluation of important point and nonpoint

sources is useful for gaining a first-order understanding

at the national level of the types of actions, and the level

of effort, that will be required to address the problem.

5 Future Eutrophic Conditions

Without preventive efforts, eutrophic conditions can be expected to continually worsen.

Assessment Data: projected population growth estimates

adapted from the U.S. Census Bureau and NOAA susceptibility data

Description: Experts at the National Workshop used

population growth and estuarine susceptibility estimates, along with their knowledge of the estuarine watersheds, to project the direction and magnitude of

change in current eutrophic conditions.

Characteristics: The reliability of this information is inherently vulnerable to unforeseen changes in input levels from nutrient pollution sources.

6 Data Gaps and Research Needs

Much remains to be done to better characterize and understand estuarine eutrophication.

Assessment Data: expert experience and knowledge, in

combination with data completeness and reliability

analysis of the Eutrophication Survey results

Description: Experts at the National Assessment Workshop identified data gaps and research needed to improve the assessment of the severity, human influence,

impacts, and appropriate responses to eutrophication

problems in estuaries.

Given all of the monitoring and research done to

date, information and knowledge is still inadequate in 48 estuaries (low confidence or inadequate data for assessment). These estuaries represent approximately 25% of the nation’s estuarine surface area.

All participants in the National Assessment process agreed that research is needed to clarify the

linkages between eutrophication and impacts on

estuarine resources, including fisheries, recreation

and tourism, and risks to human health.
viii

Executive Summary

A national strategy, which incorporates the results

of this assessment, should be developed to help

set priorities and support decision-making at the

national level.

The strategy should focus on management, monitoring, and research, and should effectively integrate with regional, state, and local programs.

For estuaries in serious condition, priorities

should focus on management action; for those in

less serious condition but at risk, the focus should

be on monitoring and prevention.

Estuaries for which there is insufficient information for evaluation should undergo basic monitoring and assessment activities.

6 Data Gaps and Research Needs, continued

7 Toward A National Strategy

Assessment results will be valuable in setting national priorities.

Assessment Data: expert experience and knowledge base

Description: These recommendations were developed

at the National Assessment Workshop from facilitated

discussions with the participating estuarine eutrophication experts.

The National Assessment process confirms that

much remains to be done to adequately characterize nutrient pressure on estuaries. Better quantification is needed of total nutrient inputs, inputs

by source, and estimators of nutrient pressure

(e.g., population, land use). Atmospheric and

groundwater inputs are least well quantified.

Better characterization of physical factors is

needed, including basic circulation patterns, effects of weather patterns, climate change, changing land use, and resultant effects on nutrient delivery, circulation, and eutrophic conditions.

Other research needs include defining the relationship between nutrient inputs and toxic blooms, better characterization of assimilative capacity, and

characterization of the effects of seasonal population changes.

Key Findings, continued
Estuarine Eutrophication: Nutrient Sources and Effects in Estuaries

Eutrophication is a process in which the addition of nutrients to water bodies stimulates algal growth. Under natural conditions, this is usually a slow

process that results in healthy and productive ecosystems. In recent decades, however, a variety of human activities has greatly accelerated

nutrient inputs to estuarine systems, causing excessive growth of algae and leading to degraded environmental conditions.

Eutrophication Diagram

ix

Atmospheric nitrogen from 

automobile and power 

plant emissions.

Nitrogen and phosphorus is 

transported to the estuary, 

where it spurs overgrowth of algae, 

causing numerous problems.

Nitrogen and 

phosphorus from 

fertilizers applied to 

crops and from 

farm animals.

Nitrogen and 

phosphorus 

from urban 

runoff. Nitrogen and 

phosphorus 

from waste 

water treatment 

plants.

Epiphytes (a type of 

algae) encrust leaf blade, 

dramatically reducing light 

available to the plant.

Thick blooms of algae or 

overabundance of macroalgae 

prevent sunlight from 

penetrating the water column.

Deeper SAV 

generally dies 

off first as light 

is diminished.

Bacteria use oxygen to 

decompose algal material.

Algae die off and settle 

to the bottom.

Oxygen from wave action 

and photosynthesis mixes with 

upper fresher water layer.

Lighter freshwater

Denser seawater 

inhibits mixing with 

upper oxygen-rich layer.

Increases occur in the duration, frequency, 

and spatial extent of nuisance/toxic blooms.

Shellfish 

become 

contaminated 

with algal 

toxins.

Immobile 

shellfish die off.

Sometimes fish kills 

occur, but more likely, 

fish avoid area.

Submerged Aquatic Vegetation (SAV) Decline Depleted Dissolved Oxygen Nuisance/Toxic Algal Blooms

Thick blooms of algae or 

overabundance of 

macroalgae generate too 

much organic matter.

Consequences

• Less habitat is available for fish and shellfish.

• Impacts on commercial and recreational fisheries.

• Impacts to tourism.

Consequences

• Less habitat is available for fish and shellfish.

• Lower commercial and recreational fish yields.

• Impacts to tourism.

• Human health endangered by exposure to toxins.

• Closure of shellfish beds to harvest.

• Impacts on commercial and recreational fisheries.

• Impacts to tourism.

Consequences

Types of sources are diverse and levels of 

nutrients generated vary greatly depending on a 

number of factors. However, population is the 

common factor that creates demand for the 

products and services that affect the level of 

nutrient pollution emanating from these sources. 

Some toxic 

blooms cause 

fish kills.

Wind blows toxins shoreward, 

where they may cause human 

respiratory problems.
x
1

Estuarine Eutrophication: Background to

the Problem

Eutrophication refers to a process in which the addition of nutrients to water bodies, primarily nitrogen and phosphorus, stimulates algal growth. This

is a natural process, but it has been greatly accelerated by human activities. Estuaries have always received nutrients from natural sources in the watershed and from the ocean. In recent decades, however, population growth and related activities, such

as various agricultural practices, wastewater treatment plants, urban runoff, and the burning of fossil

fuels, have increased nutrient inputs by many times

the levels that occur naturally.

Increased nutrient inputs promote a complex array

of symptoms, beginning with the excessive growth

of algae, which, in turn, may lead to other, more serious symptoms. In addition to the rate of algal

growth, nutrient inputs may also affect which algal

species are favored. This process is poorly understood, but some unfavorable species (e.g., Pfiesteria)

appear to be linked to nutrient inputs.

This report presents the results of a comprehensive National Assessment to address the problem of estuarine eutrophication.

The assessment includes evaluations of eutrophic conditions, human influence, impaired estuarine uses, future conditions,

data gaps and research needs, and recommendations for a national strategy to respond to the problem.

Eutrophication refers to a process in

which the addition of nutrients to

water bodies stimulates algal growth.

In recent decades, human activities

have greatly accelerated nutrient inputs, causing the excessive growth of

algae and leading to degraded water

quality and associated impairments of

estuarine resources for human use.

Introduction

In recent decades, eutrophication problems have

been reported globally, from the Baltic, Adriatic, and

Black Seas, to the estuaries and coastal waters of Japan, China, and Australia. Eutrophic symptoms

have also been observed in the United States, including the Chesapeake Bay, Long Island Sound, and the

northern Gulf of Mexico. More recently, it has become clear that nearly all U.S. estuaries exhibit some

level of eutrophic symptoms, although the scale, intensity and impacts vary widely, as do the levels of

nutrient inputs that produce these symptoms.

Whether nutrient additions result in degraded water quality depends on the extent of additional input and on natural characteristics that affect estuarine susceptibility to nutrients. In some estuaries, nutrients cause dense algal blooms to occur for months

at a time, blocking sunlight to submerged aquatic

vegetation. Decaying algae from the blooms uses

oxygen that was once available to fish and shellfish.

In other estuaries, these or other symptoms may occur, but less frequently, for shorter periods of time,

or over smaller spatial areas. In still other estuaries,

the assimilative capacity, or ability to absorb nutrients, may be greatly reduced, though no other symptoms are apparent. These eutrophic symptoms are

indicative of degraded water quality conditions that

can adversely affect the use of estuarine resources,

including commercial and recreational fishing, boating, swimming, and tourism. Eutrophic symptoms

may also cause risks to human health, including serious illness and death, that result from the consumption of shellfish contaminated with algal toxins, or

from direct exposure to waterborne or airborne toxins.

It should be noted that although nutrients cause

eutrophic symptoms, other human and natural influences may cause or affect the expression of such A red tide causes a fish kill.

Photo courtesy of Woods Hole Oceanographic Institution
2

Introduction

symptoms. These influences include engineered

water flow, which decreases estuarine flushing rates;

and development, dredging, and disease, which

change nutrient assimilative capacity through losses

of wetlands, sea grasses, oysters, and other filter

feeders. In addition to nitrogen and phosphorus,

there are other nutrients (e.g., silica) and trace elements that may be important under certain conditions, but their role is less understood.

Climate changes may also be significant for future

conditions. Global warming may result in increased

water temperatures, causing lower dissolved oxygen with no changes in nutrient inputs. At the same

time, flushing times and exchange rates might increase with rising sea levels, which could possibly

offset these effects.

For more than 40 years, scientists and natural resource managers have worked to understand, document, and resolve the complex issues associated with

eutrophication in the nation’s estuaries. Nonetheless,

information concerning algal blooms, low dissolved

oxygen, and other eutrophic symptoms was slow to

capture the attention of the public, administrators,

and legislators. Recently, the consequences of these

symptoms have become more apparent, helping to

raise awareness of nutrient-related environmental

problems. For instance, extensive losses of submerged aquatic vegetation and the associated loss

of fish habitat have occurred, many coastal water

bodies have suffered worsening episodes of low dissolved oxygen, and blooms of nuisance and toxic

algae have been occurring in new areas. For example,

Pfiesteria was first identified as a major fish-killing

agent in the Neuse and Pamlico River estuaries of

North Carolina in 1992; in 1997, outbreaks occurred

in tributaries of the Chesapeake Bay, where they had

previously not been observed.

Given the rising concern of the scientific community and the public at large, NOAA began to investigate and evaluate the need for a more deliberate

national response to the problem of estuarine

eutrophication. In order to determine the national

extent of this problem and to provide a basis for an

appropriate and effective national response, it was

necessary to survey the overall symptoms of

eutrophication within the nation’s estuaries. Historical information and ongoing field programs offered

the raw materials, but the task remained to construct

a comprehensive and consistent characterization of

the symptoms of eutrophication. In addition, it was

essential to present the results of the survey within

the context of everyday use impairments (e.g., swimming, fish consumption) that are important to the

American public. In fact, the population of U.S.

coastal and upstream areas is projected to increase

by more than 13 percent by 2010, suggesting that

nutrient-related problems are likely to get worse.

This underscores the need to stimulate additional

public involvement by presenting and publicizing

the best available information to concerned citizens,

resource managers, and policy makers alike.

Figure 1. Data characteristics of NOAA’s Estuarine Eutrophication Survey

*See Appendix A for detailed descriptions of the symptoms.

DATA SHEETS COMPILED FOR 138 ESTUARIES REGIONAL DATA SUMMARIES COMPILED

Between 120 - 1,200 Data Values per Estuary

Chlorophyll a

Turbidity

Suspended Solids Problems

Nuisance Algae Problems

Toxic Algae Problems

Macroalgae Problems

Epiphyte Problems

Total Dissolved Nitrogen

Total Dissolved Phosphorus

Anoxia

Hypoxia

Biological Stress

Primary Productivity Dominance

Pelagic Community Dominance

Benthic Community Dominance

Submerged Aquatic Vegetation (SAV)

Eutrophication Symptoms*

Existing Conditions

Concentrations

Presence/Absence of Conditions

Spatial Coverage

Months of Occurrence

Frequency of Occurrence

Duration of event

Trends in Conditions (1970 - 1995)

Direction and Magnitude of Change

 Frequency

 Duration

 Spatial coverage

Dominance Shifts

Contributing Factors to Change

Reliability of Information

Symptom Information Collected for 

Each Salinity Zone North Atlantic

Middle Atlantic

South Atlantic

Gulf of Mexico

Pacific

Eutrophication 

Survey Data 

Summary
3

Introduction

The Nation’s First Comprehensive

Estuarine Eutrophication Assessment

Since its inception in 1992, NOAA’s National Estuarine Eutrophication Survey has synthesized the best

available information on eutrophication-related

symptoms from more than 300 scientists and environmental managers. Recently published in five regional reports, the data characterize the spatial domain, severity, duration, frequency and past trends

of 16 eutrophication related conditions in estuaries

of the coterminous United States (NOAA 1996,

1997a, 1997b, 1997c, 1998).

The 138 estuaries characterized in this study represent more than 90 percent of both the total estuarine

water surface area and the total number of major

U.S. estuaries. Although not an estuary, the Mississippi River Plume is also included because of its importance to the Gulf of Mexico and associated estuaries to the west. Alaska, Hawaii and U.S. territories were not included in this assessment due to limited resources.

A common spatial framework (salinity zones representing tidal fresh, mixing, and saltwater environments) and predefined data categories were used to

consistently characterize the information on conditions and trends for each estuary. In all, this survey

produced an array of data containing more than

40,000 data values (120 to 1,200 per estuary; Figure

1). While providing the best possible information on

the problem, this array of data was also challenging

to interpret.

The National Report: A Challenge to

Interpret the Data

NOAA worked with a “Core Group” of 15 scientists

and resource managers (see Acknowledgments) to

develop and apply methods that would best integrate the survey data for each estuary. It seemed reasonable that eutrophication symptoms and their

time/space characteristics could be combined in a

way that provided a single value to represent the

status of eutrophication symptoms in each estuary.

Moreover, this index would allow comparisons,

ranking, and priority-setting among

estuaries, as well as facilitate summaries of national and regional results. To accomplish this, two obstacles—data quality and a lack of

methodology for combining numerous parameters into a single value—

would have to be overcome.

Data Quality. An analysis of data

completeness and the reliability of

symptom data was performed for

all estuaries so that confidence levels could be estimated for the data.

For 17 estuaries, symptom data

were so limited that an assessment

of overall eutrophic conditions

could not be made. Most of these

were on the Pacific Coast. For 31

other systems, some of the symptom data provided by the experts

was rated as “speculative” because

it was based on spatially or temporally limited field observations. The

overall confidence levels for these

estuaries was therefore assessed as

low. The evaluations for each symptom were carried through the assessment process to provide a basis

for assigning a confidence rating to the overall assessment of eutrophic conditions. This confidence

evaluation is important, because incomplete or uncertain data were sometimes included in the overall

assessment because it was the best information available.

Developing a Methodology to Aggregate Symptom Data.

There was no method available for combining sympExperts interpret survey results at the National Assessment Workshop.
4

Introduction

tom data into a single assessment for each estuary;

therefore, the Core Group had to address several

questions while determining the best way to integrate the existing data:

Are all eutrophic symptoms and their characteristics equally important? Should all 16 symptoms

be considered in the national assessment? Do certain symptoms logically group or occur in a linear

sequence?

Do all eutrophic symptoms have the potential to

exist in all estuaries?

Is the threshold for symptoms the same in all estuaries? For example, does a given concentration

of chlorophyll a represent “high” eutrophic symptoms in all estuaries?

The Eutrophication Model. To help overcome these

obstacles and properly interpret the information, the

Core Group participated in two work sessions to develop and test several analytical and numerical

methods. Ultimately, a single model was developed

that made maximum use of the survey data. While

this model does not account entirely for the complexity of this issue, it uses available information to

best describe the sequence and severity of eutrophic

conditions (Figure 2). The model used six symptoms

that were most directly related to nutrient inputs.

Three primary symptoms, algal abundance (using

chlorophyll a as an indicator), epiphyte abundance,

and macroalgae, represent the first possible stage of

water-quality degradation associated with eutrophication. Although nitrogen and phosphorus concentrations in the water column are related to nutrient

inputs, they are also influenced by other biological

and chemical processes. As a result, elevated concentrations do not necessarily indicate that eutrophic

symptoms are present, nor do

low concentrations necessarily

indicate that eutrophication is

not present. As an example,

chlorophyll a concentrations

may be very high while dissolved nutrient concentrations

are low. This scenario is common during peak phytoplankton production because these

organisms assimilate the nutrients very efficiently. Thus, nutrient concentrations in the water column were not included as

primary symptoms in the

model.

In many estuaries, the primary

symptoms lead to secondary

symptoms, such as submerged

aquatic vegetation loss, nuisance and toxic algal blooms (although for toxic forms the linkage is not well established), and

low dissolved oxygen. In some

cases, secondary symptoms can

exist in the estuary without

originating from the primary

symptoms. This occurs, for instance, in many North Atlantic

estuaries where toxic algal

blooms are transported from the

coastal ocean. In other places,

disease or suspended sediments

have contributed to declines in

submerged aquatic vegetation.

Nitrogen and 

Phosphorus

Extreme Chl-a

Concentrations

Problematic 

Epiphytic Growth 

SAV Spatial 

Coverage

Diatoms to 

Flagellates

Benthic 

Dominance to 

Pelagic 

Dominance

Anoxia

Hypoxia

Biological Stress

Nuisance Bloom 

Problems

Toxic Bloom 

Problems

Primary 

Symptoms

Secondary 

Symptoms

Extreme Chl-a

Concentrations

Problematic 

Macroalgal

Growth

Problematic 

Macroalgal

Growth

Loss of Submerged 

Aquatic Vegetation

SAV Spatial 

Coverage Trends

Decreased Light 

Availability

Algal Dominance 

Changes Harmful Algae 

Increased 

Organic Matter

Decomposition

Low Dissolved 

Oxygen 

External 

Nutrient Inputs

Figure 2. The simplified eutrophication model used for the National Assessment

•

•

•
5

Introduction

Determining Overall Eutrophic Conditions. A numerical scoring system was developed to integrate

information from all six primary and secondary

symptoms to determine the overall status of

eutrophic symptoms in each estuary. This scoring

system was implemented in three phases according

to the methods described in Figure 3 (see Appendix

A for a detailed description).

First, a single index value was computed from all

primary symptoms. The scoring system gave equal

weight to all three symptoms and considered the

spatial and temporal characteristics of each. The

scores for the three symptoms were then averaged,

resulting in the highest values being assigned to estuaries having multiple primary symptoms that occur with great frequency, over large spatial areas of

the estuary, and for extended periods of time. Likewise, the lowest scores indicate estuaries that exhibit

few, if any, characteristics of the primary symptoms.

Next, a single index value was computed from all

secondary symptoms. The scoring system again gave

equal weight to all symptoms and their spatial and

temporal characteristics. The highest score of any of

the three symptoms was then chosen as the overall

secondary value for the estuary. This weights the secondary symptoms higher than the primary symptoms, because the secondary symptoms take longer

to develop, thereby indicating a more chronic problem, and being more indicative of actual impacts to

the estuary.

Finally, the range of numeric scores assigned to primary and secondary symptoms was divided

into categories of high, moderate, and low. Primary and secondary scores were then compared in a matrix so that overall categories

could be assigned to the estuaries (Figure 3).

Estuaries having high scores for both primary

and secondary conditions were considered to

have an overall “high” level of eutrophication.

Likewise, estuaries with low primary and secondary values were assigned an overall “low”

level of eutrophication. The Core Group members, using the matrix as a guide, then assigned

scores to the remaining estuaries based on their

interpretations of each estuary’s combined

values.

Interpreting the Model Results. While the

model offered a potentially wide scale over

which to define the severity of the problem,

few of the 138 estuaries or the Mississippi River

Plume actually fell at either extreme of this continuum, where the numerical scoring systems

are more easily interpreted. Logically, estuaries with few primary symptoms and low numeric scores were considered to be relatively

unaffected by nutrient-related conditions when

compared to estuaries with both primary and

secondary symptoms and higher numeric

scores.

Most estuaries showed varying degrees of both

primary and secondary symptoms, so that the

meaning of these scores was more difficult to

determine. This was particularly true for two

conditions, for which these general guidelines

for interpretation were offered:

High or moderate primary symptoms and low secondary symptoms. These estuaries have relaPrimary and Secondary Symptom Index values are ranked and split into 

categories as follows:

Score Range Category Assigned

2

1 Individual scores are determined for the primary symptoms and combined into a 

single primary symptom index. Individual scores are determined for the secondary 

symptoms and combined into a single secondary symptom index. 

3 Primary and Secondary Symptom Categories are cross compared in a matrix to 

determine the overall level of expression of eutrophic conditions.

OVERALL LEVEL OF EXPRESSION OF EUTROPHIC CONDITIONS

LOW

MODERATE

MODERATE LOW MODERATE HIGH

Moderate secondary 

symptoms indicate 

substantial eutrophic 

conditions, but low primary 

symptoms indicate other 

factors may be involved in 

causing the conditions.

Level of expression of 

eutrophic conditions is 

minimal.

High secondary symptoms 

indicate serious problems, 

but low primary symptoms 

indicate other factors may 

also be involved in causing 

the conditions.

Primary symptoms 

beginning to indicate 

possible problems but 

still very few secondary 

symptoms expressed.

Primary symptoms high but 

problems with more serious 

secondary symptoms still 

not being expressed.

Level of expression of 

eutrophic condtions is 

substantial.

Substantial levels of 

eutrophic conditions 

occurring with secondary 

symptoms indicating 

serious problems.

Primary symptoms high 

and substantial secondary 

symptoms becoming more 

expressed, indicating 

potentially serious 

problems.

High primary and 

secondary symptom levels 

indicate serious 

eutrophication problems.

MODERATE LOW HIGH

MODERATE MODERATE HIGH HIGH

Secondary Symptoms

Primary Symptoms

Low Moderate High

0 0.3 0.6 1

Low Moderate High 0.3

0.6

1

In This Report:

LOW and MODERATE LOW are grouped together as LOW.

HIGH and MODERATE HIGH are grouped together as HIGH.

> 0 < 0.3 Low

> 0.3 < 0.6 Moderate

> 0.6 < 1 High

Figure 3. Steps followed in determining the overall level of expression of

eutrophic conditions in estuaries
6

Introduction

tively well developed conditions associated with algal blooms, epiphytes, and/or macroalgae, which

suggests that they are in the early stages of eutrophication and may be on the edge of developing more

serious conditions. These systems may be susceptible to additional nutrient inputs and could begin

to develop secondary symptoms of eutrophication.

High or moderate secondary symptoms and low primary

symptoms. For these estuaries, advanced secondary

symptoms exist, even though the “prerequisite” primary symptoms (as suggested by the model) may

not be well developed. Three possible interpretations

are offered to describe these conditions. For some

estuaries, the secondary conditions were transported

from offshore coastal areas, rather than originating

within the estuary. This occurs, for example, with

toxic bloom conditions in North Atlantic estuaries.

Alternatively, it is possible that nutrient-related water quality conditions have recently improved, but

the response time to reduce secondary symptoms is

longer than it is for primary symptoms. The secondary symptoms that remain may be residual conditions that also may improve as nutrient concentrations continue to decrease. Finally, it is possible that

secondary conditions in an estuary are related only

partially, or not at all, to nutrient enrichment. For

example, submerged aquatic vegetation losses in Long

Island Sound have been attributed to both disease and

nutrient enrichment.

Through the use of a simple model, a framework

was established to help understand the sequence,

processes, and symptoms associated with nutrient

enrichment. Despite its limitations (e.g., the model

does not account for changes in assimilative capacity from losses of wetlands), the model represents

the first attempt to synthesize large volumes of data

and to derive a single value for eutrophication in

each estuary. With this foundation, the next steps

are to (1) expand understanding of the relationship

between eutrophication and nutrient sources, and

(2) evaluate appropriate responses to the problem.

Extending the Assessment: Toward a

National Strategy

This National Assessment focuses on the data in

NOAA’s Estuarine Eutrophication Survey, the fundamental goal of which was to describe the scale,

scope, and severity of nutrient enrichment conditions nationwide, and to compare the various expressions of eutrophic symptoms in individual estuaries. In a sense, the model represents a form of

environmental triage—separating estuaries that are

in serious condition, but could potentially improve,

from those that presently do not experience many

symptoms, but are seemingly at risk. In turn, this

represents a starting point for understanding why

these conditions exist, how and why conditions differ across estuaries, whether certain problematic conditions may respond to remedial actions, and which

of these actions would best protect estuaries from

further degradation.

To do so means to go beyond the survey data. At the

very least, more information is needed about the

magnitude and sources of nutrient inputs, the natural ability of estuaries to flush or assimilate incoming nutrients, and the relative influence of both of

these factors on the expression of eutrophication.

Moreover, these results need to be associated with

use impairment and public health issues that bring

the message to the public and help to set priorities

for management and research activities. With the

guidance of the Core Group, the National Assessment was expanded to include additional data sets

that begin to examine these linkages.

Expanding the Model. To accommodate the additional analyses, the original eutrophication model

was expanded (Figure 4) so that eutrophic symptoms could be compared with other national data

sets, specifically estuarine transport (i.e., flushing,

also referred to as susceptibility), nutrient inputs and

sources, and eutrophication-related estuarine use

impairments. The data for these assessments were

derived from a variety of sources, described below.

These assessments were intended to allow general

observations about the linkages between symptoms,

nutrient loading and susceptibility, and between

eutrophic conditions and use impairments. Recommendations for potential responses to the problem

were developed from conclusions based on these

observations.

Susceptibility. Estimates were made of the natural

tendency of an estuary to retain or export nutrients.

The rate at which water moves through the estuary

was determined by examining tidal action and the

volume of freshwater flowing in from rivers. In general, if the water (and nutrients) are flushed quickly,

there is not sufficient time for problems to develop

and the estuary is not particularly susceptible. If the

estuary acts more like a bathtub, with nutrient-rich

water sitting in the system for a long time, then there

is time for nutrients to be taken up by algae. These

estuaries are more susceptible to developing

eutrophic symptoms.

Although only dilution and flushing were included

in this susceptibility estimate, biological processes

may also affect susceptibility. For instance, filter feeders raise an estuary’s capacity to assimilate more
7

Introduction

nutrients before showing symptoms. Wetlands,

which retain nutrients that might otherwise enter

estuarine waters, also improve an estuary’s ability

to fend off eutrophic symptoms.

Nutrient Inputs. The level of nutrients entering estuaries is a critical factor in determining the level to

which they will develop symptoms. Excess nutrient

inputs are mainly human-related and are due to high

coastal population density, various agricultural practices (e.g., fertilizer applications, animal feedlot operations), the burning of fossil fuels, and sewage

treatment effluents.

Estuarine Use Impairments. Impaired resources (in

terms of human use) were evaluated to gain a basic

understanding of the level of negative impacts occurring in the nation’s estuaries. These include impacts to recreational activities, such as swimming

and boating, as well as to commercial operations,

such as fishing and shellfishing.

Potential Management Concerns. Evaluations were

also made of the most important sources to target in

order to manage nutrient inputs into estuaries.

Data Sets and Data Quality. NOAA had access to

national data sets that were used for characterizations; however, the assessments were largely based

on the knowledge and experience of the Core Group

and other Workshop participants.

For nutrient-loading estimates, NOAA provided

comparative data for 1987 (adapted from the U.S.

Geological Survey’s SPARROW model; Smith et al.,

1997) for five major sources: fertilizer, livestock

wastes, point sources, atmospheric deposition, and

nonagricultural sources. In addition, NOAA provided information on coastal population and land

usage, which were used as comparative estimators

of loading. Estuarine susceptibility estimates were

based on an estuary’s dilution potential and flushing potential, which are calculated from freshwater

Nitrogen and 

Phosphorus

USGS SPARROW MODEL, NOAA CA&DS 

DATA, CORE GROUP EUTROPHICATION SURVEY DATA CORE GROUP

Potential Effects and 

Use Impairments

Decreased 

Light Availability

Loss of 

Submerged 

Aquatic 

Vegetation

Algal 

Dominance 

Changes

Nuisance/Toxic 

Algal Blooms 

Increased 

Organic Matter 

Production

Low 

Dissolved 

Oxygen 

Secondary 

Symptoms

Primary 

Symptoms

External Nutrient Inputs 

and Susceptibility

Loss of Habitat

Commercial Fishing 

Recreational Fishing

Tourism

Offensive Odors

Aesthetic Values

Tourism

Fish Kills

Commercial Fishing 

Recreational Fishing

Aesthetic Values

Tourism

Commercial Fishing 

Recreational Fishing

Human Health Problems

Swimming

Tourism

Increase of Algal Toxins

Loss of Habitat

Commercial Fishing 

Recreational Fishing

Tourism

Influence of 

Physical and 

Biological 

Processes

 (i.e. freshwater 

inflow, flushing, 

wetlands uptake, 

filter feeders)

Figure 4. The expanded eutrophication model
8

Introduction

inflow, tidal prism, and estuary geometry (NOAA’s

Coastal Assessment & Data Synthesis System, 1998).

These data sets were synthesized and interpreted less

rigorously than the symptom data, and thus, were

more speculative than the data for eutrophic symptoms.

The assessment of estuarine-use impairments and

management targets was not based on hard data;

rather, it was derived from the expert knowledge of

participants at the National Assessment Workshop.

Despite the speculative nature of these assessments,

the information was still very useful, providing insight into the consequences of eutrophic symptoms

in estuaries, and into the most effective management

actions for reducing them.

See Appendix A for details on the methods and information sources used in the assessment.

Organizing the Results: Seven Key

Questions

Seven questions, which follow the logic sequence of

the expanded eutrophication model, were developed

to help organize results for the National Assessment.

Question 1 examines the results of the model. Questions 2 through 4 examine linkages between these

symptoms, pollution sources, and coastal use impairments. Questions 5 through 7 identify priority

management, monitoring, and research needs.

1. What are the severity and extent of eutrophic conditions exhibited within the estuaries of the United

States?

This analysis is based on the eutrophication data set

and its interpretation using the eutrophication

model.

2. To what extent are eutrophic conditions in U.S.

estuaries caused by human activities?

The U.S. Geological Survey SPARROW model provided first-order estimates of nutrient loads for 1987

from five major sources. Population estimates and

Agricultural Census data also were used to represent the potential for nutrient sources. In addition,

an indicator of estuarine flushing potential was developed based on freshwater inflow, tide, and estuarine geometry.

3. To what extent do eutrophic conditions impair

the use of estuarine resources, and what are the important impaired uses?

Core Group members selected from a list of seven

use impairments for each estuary. This list included

recreational and commercial fishing, fish consumption, shellfishing, swimming, boating, aesthetics, and

tourism.

4. Where should management efforts be targeted to

achieve the greatest benefit toward remediation and

protection from future degradation, and what are

the most important sources to target?

Core Group members selected from a list of 10 point

and nonpoint nutrient source targets.

5. To what extent can the severity and extent of

eutrophic conditions be expected to increase by the

year 2020, given the natural susceptibility of estuaries and the potential for increasing nutrient inputs?

Projected population growth estimates were used

to represent the potential for future nutrient inputs

and thus, changes in eutrophic conditions. Susceptibility was used to determine the expected severity

of change.

6. Which data gaps and research and monitoring

needs are most critical in terms of improving the

ability to assess and respond to eutrophic conditions?

Core Group members listed these, based on their experience and the findings of Questions 1 through 5

above.

7. How can the results of this assessment be translated into a national strategy?

Recommendations were developed from discussions

between members of the Core Group.

Using this Report and the Data

This report contains five sections that are organized

according to the seven questions listed above. The

report emphasizes the results from the eutrophic

symptoms model (i.e., Question 1) as they represent

the culmination of the multi-year survey work and

provide an unprecedented classification for the

nation’s estuaries. The results of the expanded assessment model (i.e., Questions 2 through 7) are also

provided, but at a more general level consistent with

the less rigorous methods of data collection. The

most direct responses to the seven questions are provided in the Executive Summary, while the National

Overview and Regional Summaries sections are

supplemented by mapped and tabular displays of

the synthesized results. The Conclusions and Recommendations sections propose next steps, as suggested by the Core Group and other Workshop participants. The data and methods used in this National Assessment are described in the Appendices.

The digital data can be accessed on-line at:

http://cads.nos.noaa.gov
9

National Overview

The expression of overall eutrophic conditions is high in 44 U.S. estuaries. These

estuaries are located mainly in the Gulf

of Mexico and Middle Atlantic regions;

however, certain estuaries along all

coastlines exhibit high levels of

eutrophic conditions.

This assessment characterizes the overall eutrophic conditions and the water-quality problems associated with nutrient

enrichment for 138 U.S. estuaries. A Core Group of eutrophication experts collaborated with NOAA and was instrumental

in developing methods to assess the results of the National Eutrophication Survey. At a National Assessment Workshop,

the Core Group and additional experts reviewed and interpreted the Survey results, and analyzed the factors that influence

the development of problematic conditions. They also reported on impairments in estuarine uses, potential management

concerns, and the future outlook to the year 2020. Note that the Mississippi River Plume was also characterized, and is

counted as an additional “estuary” in the figures, but is not included in surface area statistics.

Eutrophic Conditions

The assessment of overall eutrophic conditions is

based on the combined level of expression of six

symptoms: chlorophyll a, epiphyte abundance,

macroalgal abundance, depleted dissolved oxygen,

submerged aquatic vegetation loss, and nuisance/

toxic algal blooms. The level of expression of each is

determined by the concentration, spatial coverage,

frequency of occurrence, and/or other factors (refer

to Figure 3, page 5).

For each symptom assessment, an evaluation of the

level of confidence was made based on the temporal and spatial representativeness of the data. The

confidence evaluation is important, because in some

cases the data were incomplete or uncertain, but still

provided the best information available and the only

means of presenting a national picture. These symptom confidence ratings provided the basis for evaluating the confidence of overall eutrophic conditions.

The data for 17 estuaries were too sparse to provide

an overall view of eutrophic conditions although

limited data existed for certain symptoms in some

of these estuaries (see page 18 for list). For an additional 38 estuaries, the overall assessment confidence

was rated as low (see Appendix B).

Figure 5. Level of expression of eutrophic conditions Figure 6 . Eutrophic conditions by region

Overall Conditions. National Assessment Workshop participants concluded that the expression of

overall eutrophic conditions was high in 44 estuaries, representing 40% of the total estuarine surface

area studied (Figure 5). These estuaries were located

mainly in the Gulf of Mexico and Middle Atlantic

regions; however, some estuaries along all coastlines

exhibited high levels of eutrophic conditions (Figures 6 and 7). This means that in these estuaries, one

or more symptoms occurred at problem levels every year, or persistently, across a major part of each

estuary. An additional 40 estuaries exhibited moderate eutrophic conditions. When considered together, the estuaries with moderate to high conditions represent 65% of the estuarine surface area

studied. The remaining 38 estuaries exhibited low

Moderate Moderate Low

5

10

15

20

25

30

35

High Moderate High Low

5

10

15

20

25

30

35

North 

Atlantic Middle 

Atlantic South 

Atlantic

Gulf of 

Mexico

Pacific

Number of Estuaries

Number of Estuaries

Eutrophic Condition

High

Moderate High

Moderate

Moderate Low

Low

Grouped as High in this Report Grouped as Low in this Report

0 High

0 Low

Low Confidence

Moderate to High 

Confidence

Moderate High to 

High Expression Moderate Expression Moderate Low to 

Low Expression

Low Confidence

Moderate to High 

Confidence

Low Confidence

Moderate to High 

Confidence

Eutrophic Condition and Assessment Confidence

Grouped as High in this Report

Grouped as Low in this Report

National Overview
10

National Overview

Boston Harbor

Chesapeake Bay Mainstem

Barnegat Bay

Delaware Inland Bays

Patuxent River

Potomac River

Neuse River

Lake 

Pontchartrain

Florida Bay

Upper Laguna Madre

Baffin Bay

Lower Laguna Madre

Mississippi 

River Plume

Corpus Christi Bay

San Francisco Bay

Tijuana Estuary

Newport Bay

York River

Tangier/Pocomoke Sounds

Long Island Sound

Gardiners Bay

Great South Bay

St. Croix River/Cobscook Bay

Englishman Bay

Narraguagus Bay

Sheepscot Bay

Casco Bay

Tomales Bay

Elkhorn Slough

Pamlico/Pungo Rivers

St. Johns River

Calcasieu

Lake

Tampa Bay

Sarasota Bay

Charlotte Harbor

Caloosahatchee R.

Galveston Bay

Choctawhatchee 

Bay

San Antonio Bay

New River

South Ten Thousand Islands

Hood Canal

South Puget 

Sound

High Levels of Expression of Eutrophic Conditions

Perdido Bay

Forty-four estuaries along all of the nation’s coasts were assessed by workshop participants as showing high expressions of eutrophic conditions. The

Middle Atlantic and Gulf of Mexico have the highest percentages of estuaries with high eutrophic conditions. The Pacific and South Atlantic regions

contain the highest percentage of estuaries that lack sufficient information to confidently assess eutrophic conditions. An additional forty estuaries (not

shown) have moderate levels of eutrophic conditions.

Note: Conditions are not necessarily related in whole to human-related eutrophication; to various degrees natural causes and other human disturbances

may also play a role. For instance, some estuaries in Maine are typified by natural occurrences of toxic algae, which drift in from the open ocean. Once in the

estuary, however, these blooms may be sustained by human nutrient inputs.

Figure 7. Estuaries with high levels of expression of eutrophic conditions Estuaries in this category exhibit varying combinations of eutrophic symp- toms, including high expressions of chlorophyll a, macroalgal abundance problems, epiphyte abundance problems, low dissolved oxygen, nuisance and toxic algal blooms, and loss of submerged aquatic vegetation. Typi- cally, this means that one or more of these symptoms occur over large ar- eas of the estuary, annually or persistently, and/or for long durations.
11

National Overview

Chlorophyll a is a measure used to indicate the amount of

microscopic algae, called phytoplankton, growing in a water body. High concentrations are indicative of problems

related to the overproduction of algae.

Epiphytes are algae that grow on the surfaces of plants or

other objects. They can cause losses of submerged aquatic

vegetation by encrusting leaf surfaces and thereby reducing the light available to the plant leaves.

Macroalgae are large algae, commonly referred to as “seaweed.” Blooms can cause losses of submerged aquatic vegetation by blocking sunlight. Additionally, blooms may also

smother immobile shellfish, corals, or other habitat. The

unsightly nature of some blooms may impact tourism due

to the declining value of swimming, fishing, and boating

opportunities.

Low dissolved oxygen occurs as a result of large algal

blooms that sink to the bottom and use oxygen during the

process of decay. Low dissolved oxygen can cause fish kills,

habitat loss, and degraded aesthetic values, resulting in the

loss of tourism and recreational water use.

Losses of submerged aquatic vegetation (SAV) occur when

light is decreased due to turbid water associated with overgrowth of algae or as a result of epiphyte growth on leaves.

The loss of SAV can have negative effects on the ecological

functioning of an estuary and may impact some fisheries

because the SAV beds serve as important habitat.

Nuisance and toxic algal blooms are thought to be caused

by a change in the natural mixture of nutrients that occurs

when nutrient inputs increase over a long period of time.

These blooms may release toxins that kill fish and shellfish.

Human-health problems may also occur due to the consumption of seafood that has accumulated algal toxins or from the

inhalation of airborne toxins. Many toxic algal blooms occur

naturally; however, the role of nutrient enrichment is unclear.

Common Symptoms of Eutrophication

Figure 8. Level of expression of symptoms within each overall category of eutrophic condition

levels of eutrophic conditions, meaning that symptoms were not observed at problem levels or that

problem conditions occurred infrequently or only

under specific and unusual circumstances. About

half of these estuaries were located in the South Atlantic and Pacific regions.

In more than 80 percent of estuaries with high and

moderate levels of eutrophic conditions, the assessment confidence was high; conversely, confidence

was high in fewer than half of the systems assessed

as having low eutrophic conditions. Most of the estuaries with low confidence are located in the Pacific and South Atlantic regions.

Symptoms: Common Signs of Eutrophication. The

immediate response to nutrient inputs is the overgrowth of algae. The primary symptoms of increased

nutrient concentrations in the water column are high

levels of chlorophyll a, epiphytes, and/or

macroalgae (see sidebar, right). It is thought that once

primary symptoms are observed at high levels, an

estuary is in the first stages of displaying undesirable eutrophic conditions.

High expressions of chlorophyll a occurred in 39 estuaries, high expressions of macroalgal abundance

occurred in 24 estuaries, and high expressions of epiphyte abundance occurred in 11 estuaries (see Figure 8 for an accounting of symptom expression broken down by eutrophic condition category). Overall, at least one of these primary symptoms was expressed at high levels in 58 estuaries. In some cases,

high levels may be natural, but this observation indicates that 40 percent of the nation’s estuaries may

be in the first stages of developing problems associated with eutrophication. On a regional basis, epi10 20 30 40

Chlorophyll a

Epiphyte 

Abundance

Macroalgal 

Abundance

Low Dissolved 

Oxygen

Submerged 

Aquatic 

Vegetation Loss

Nuisance/

Toxic Algae

10 20 30 40 10 20 30 40

Primary Symptoms Secondary Symptoms

High Moderate Low

High Eutrophic Conditions

(44 Estuaries)

Moderate Eutrophic Conditions

(40 Estuaries)

Low Eutrophic Conditions

(38 Estuaries)

50

Number of Estuaries Number of Estuaries Number of Estuaries

Symptom 

Expression
12

National Overview

phyte problems occurred mainly in Gulf of Mexico

estuaries, while higher levels of chlorophyll a and

macroalgae were observed in estuaries of all regions

(Figure 9).

While high levels of primary symptoms are strong

indicators of the onset of eutrophication, the secondFigure 9. Expression of eutrophic symptoms

These maps depict estuaries with moderate to high levels of expression of eutrophic symptoms, indicating areas of possible

concern. Note that these symptoms are not necessarily related in whole to human-related nutrient inputs; natural causes and

other human disturbances may also play a role, to various degrees, in the expression of symptoms.

ary symptoms, which include low dissolved oxygen,

the loss of submerged aquatic vegetation, and the

occurrence of nuisance and toxic blooms, indicate

more serious problems, even at moderate levels.

Note that while there is a direct causative link between nutrients and primary symptoms, there are

many other factors, both natural and human related,

A

A A

A A

A

Primary Symptoms Secondary Symptoms

Chlorophyll a Low Dissolved Oxygen

Macroalgal

Abundance

Problems

Epiphyte

Abundance

Problems

Nuisance and/or

Toxic Algal Bloom

Problems

Submerged Aquatic

Vegetation Loss
13

National Overview

More than half of U.S. estuaries have

moderate to high expressions of at least

one of the secondary symptoms. This

finding is important because these symptoms can have serious consequences, including negative impacts on commercial

fish yields, degraded recreational opportunities, increased risks to human health,

and adverse affects on tourism.

that may contribute to the occurrence of secondary

symptoms.

Depleted dissolved oxygen was expressed at moderate or high levels in 42 estuaries. Twenty-seven estuaries had moderate or high levels of submerged

aquatic vegetation loss, and 51 estuaries exhibited

moderate or high nuisance/toxic algal blooms (Figures 8 and 9). Overall, moderate or high levels of at

least one secondary symptom was observed in 82

estuaries, representing 67% of the nation’s estuarine

surface area—an indication that eutrophication is

well developed and is potentially causing serious

problems in more than half of U.S. estuaries. The

secondary symptoms were restricted regionally, with

the exception of nuisance and toxic blooms, which

were observed in systems along all coasts. Losses of

submerged aquatic vegetation were mostly limited

to the Gulf of Mexico and Middle Atlantic regions,

This crab could not survive in the anoxic zone near the mouth

of the Mississippi River. Photo courtesy of Nancy Rabalais,

courtesy of the National Undersea Research Program.

and low dissolved oxygen was observed mainly in

the Gulf of Mexico, Middle Atlantic, and South Atlantic regions. These geographical differences may

be useful for developing regionally specific indicators that are more sensitive than the nationally applied model used here.

Completing the Picture

These results provide a picture of the overall

eutrophic conditions in the nation’s estuaries and

the specific symptoms that occur. Nevertheless,

questions remain, such as: What factors influence

the development of these symptoms? What types of

use impairments do these symptoms cause? What

are the management implications? At the National

Assessment Workshop, the Core Group used data

and information about estuarine susceptibility and

human-related nutrient inputs, which, together, provided the basis for evaluating the overall human influence on these conditions. Participants relied

heavily on their experience and prior knowledge to

evaluate estuarine-use impairments and potential

management targets. The data for these ancillary assessments were not as robust, and were less rigorously reviewed, than the Eutrophication Survey

data, and some findings were inconclusive. This information was included, however, because it helped

to complete the national picture.

Influencing Factors. In an effort to determine the

level of human influence on the development of

eutrophication, workshop participants considered

the overall eutrophic condition with respect to nutrient inputs and estuarine susceptibility to retain

nutrients. Figure 10 (next page) shows the input data

separately from the susceptibility data, as well as

the aggregated results, which represent the overall

level of human influence. Although both phosphorus and nitrogen cause nutrient enrichment problems in estuaries, at the time of the Assessment

Workshop, national-level information was available

only for nitrogen inputs. For this reason, nitrogen

values were used as the primary estimates of nutrient inputs, and information on population density

and land use was used as a general indicator of nutrient pressure to help account for phosphorus and

corroborate nitrogen estimates. The nitrogen input

estimates were based on watershed monitoring data

from the U.S. Geological Survey, as produced by the

SPARROW model (Smith et al., 1997).

While these data were variable and did not show

distinct groupings, some generalizations could be

made. Many estuaries assessed as having high levels of overall eutrophic conditions also had high susceptibility and moderate to high levels of nutrient
14

National Overview

inputs. These estuaries are very sensitive to nutrient inputs, and as a result, many were assessed as

having a high level of human-related influence on

the development of eutrophic conditions. The converse also seems to hold true; that is, most estuaries

with low susceptibility and low inputs of nutrients

had a low overall level of eutrophic conditions. These

estuaries are less sensitive to development of

eutrophic conditions even with human related nutrient inputs.

The assessment results highlight these generalizations; of the 44 estuaries with high levels of eutrophic

conditions, workshop participants assessed 36 as

having a high level of human influence on the development of conditions. It is important to note that

a common feature of these estuaries was high or

moderate susceptibility. It is also noteworthy that

most of the 44 estuaries have moderate, not high (as

in only six of the estuaries), levels of nutrient inputs.

In estuaries with high or moderate susceptibility,

even a moderate level of nutrient input may be sufficient to cause serious eutrophic symptoms. In these

systems, natural estuarine characteristics, such as

low tidal exchange, enhance the expression of symptoms. Most of these estuaries were located in the

Gulf, Middle Atlantic, and Pacific regions.

In contrast, 38 estuaries exhibited low overall

eutrophic conditions. The common traits of these

estuaries were lower susceptibility and lower nitrogen inputs; 31 of these estuaries had moderate or

low nitrogen inputs, and 28 had moderate or low

susceptibility. In these systems, natural characterisFigure 10. Influencing factors on the expression of eutrophic conditions

Estuarine Susceptibility

The estuarine susceptibility estimates are based on estuarine

flushing and dilution capacity - freshwater inflow, tidal flushing, and degree of stratification. These characteristics influence the transport and fate of nutrients in coastal water bodies, and help to determine the susceptibility of an estuary to

retain nutrients. These data were derived from national data

sets contained in NOAA’s Coastal Assessment and Data Synthesis system.

Overall Human Influence

An estimation of the overall level of human influence on the

expression of eutrophic conditions was determined for each

estuary by combining estuarine susceptibility estimates with

indicators of nutrient pressure. Although nitrogen input was

used as the primary indicator of nutrient pressure, workshop

participants made appropriate modifications to the overall

nutrient pressure assessment, based on analysis of population density and land use data as general nutrient pressure

indicators.

Nitrogen Inputs

Nitrogen yield estimates, adapted from USGS’s SPARROW

model, characterize the level of nitrogen inputs to estuaries

for five major nutrient source types: point sources, fertilizer,

livestock, atmospheric deposition, and nonpoint/nonagricultural. These data provide a rough snapshot estimation of nitrogen input conditions for 1987.

At the National Assessment Workshop, an attempt was made to characterize the natural conditions and human activities that influence the

expression of eutrophic conditions in the nation’s estuaries. The purpose was to develop an understanding of why eutrophic conditions differ

among estuaries and to provide a basis for guiding management responses to problems. These figures indicate that the response to a given

level of nutrient is highly variable and is primarily due to differences among estuarine susceptibility to nutrients. Some estuaries are so

susceptible that only small amounts of additional nutrients will cause problems, while others can seemingly take in large quantities and still

display few eutrophic symptoms (but may pass the nutrients on to other receiving bodies downstream).

9 8

5

19 19

13

10

13

25

Susceptibility

Eutrophic Condition

Low Moderate High

High

Moderate

Low

Number of Estuaries

16

12 13

15

22 22

4 3 6

Eutrophic Condition

Nitrogen Input

Low Moderate High

High

Moderate

Low

Number of Estuaries

21

(14)

10

(2) 6

(0) 7

(4)

19

(10)

8 2 (1)

(4)

11

(2)

36

(5)

Low Moderate High

Eutrophic Condition

Overall Human Influence

High

Moderate

Low

Number of Estuaries

(parentheses indicate fraction 

of total with low confidence)
15

National Overview

Most estuaries with high eutrophic

conditions also have high levels of human influence due to a combination of

moderate to high nutrient inputs and

natural susceptibility.

tics appeared to suppress the expression of symptoms. It should be noted, however, that 10 of the estuaries with low eutrophic conditions exhibited high

susceptibility.

It is important to note that although these generalizations can be made, the relationships between nutrient inputs and the expression of symptoms, or

between susceptibility and the expression of symptoms (Figure 10), are not entirely predictable. For instance, not all of the 44 estuaries with high eutrophic

conditions had high nutrient inputs and high susceptibility, though most did follow this general rule.

There were exceptions, including six estuaries assessed with high levels of eutrophic conditions and

low human influence. Five of these are located in

the North Atlantic region, where susceptibility is low

due to tidal ranges greater than six feet, and nitrogen inputs are generally low due to low population

densities and densely forested watersheds. The overall eutrophic conditions in some of these estuaries

were assessed as high because toxic blooms occurred

each year; these events were natural, however, originating offshore and then drifting into the estuaries.

Once a bloom has reached an estuary, it is possible

that land-based nutrients maintain it.

Impaired Uses Relative to Symptoms. The finding

that more than half of the nation’s estuaries have

moderate to high expressions of at least one secondary symptom of eutrophication is of considerable

importance, because these symptoms may negatively impact estuarine resources in a variety of ways

(Figure 11). For instance, losses in the nation’s fishery resources may be directly caused by fish kills

associated with low dissolved oxygen and toxic

blooms. Declines in tourism occur when low dissolved oxygen causes noxious smells and floating

mats of algae create unfavorable aesthetic conditions.

Risks to human health increase when the toxins from

algal blooms accumulate in edible fish and shellfish,

and when toxins become airborne, causing respiratory problems due to inhalation. This report does

not directly address economic losses, however, seasonal economies may suffer when

eutrophic symptoms occur during

the height of the tourist and/or

fishing seasons. The cost of implementing strategies to reduce nitrogen inputs may also be considerable. For example, the U.S. Environmental Protection Agency’s Long

Island Sound Study reported in

1998 that the potential cost of reducing nitrogen levels from point

sources alone (70 treatment plants)

in the Long Island Sound watershed would be about $2.5 billion.

The magnitude of estuarine impacts cannot currently be quantiShellfishing is a typical impaired estuarine use. Photo courtesy

of Zoe Rasmussen, Puget Sound Water Quality Action Team.

Figure 11. Number of estuaries with resources impaired for human use

Pacific 12 0 11 4 0 5 0

Gulf of Mexico 11 5 12 4 1 4 10

South Atlantic 8 3 3 1 1 02

Middle Atlantic 12 0 9 6 2 8 2

North Atlantic 0 0 11 0 1 0 0

National 43 8 46 15 5 17 14

Region

Number of Estuaries With Impaired Uses

Commercial/Recreational Fishing

Fish Consumption

Shellfish

Swimming

Boating

AestheticsTourism

12

16

9

19

13

69
16

National Overview

Experts at the National Assessment

Workshop predicted that more than

half of the nation’s estuaries are likely

to develop worsening eutrophic conditions during the next 20 years.

fied; however, eutrophication experts at the National

Assessment Workshop identified estuarine uses that

they knew or suspected to be impaired because of

eutrophic symptoms (Figure 11). Although this information is qualitative, it is still useful in understanding the nature of impaired uses on a national

basis. In all, some type of use impairment was identified in 69 estuaries. The most frequently reported

impairments were to commercial fishing and shellfish harvesting. Considered regionally, fishing and/

or shellfishing impairments were reported for all

coasts. Other frequently reported impairments were

aesthetics in the Middle Atlantic, and tourism in the

Gulf of Mexico region. The loss of assimilative

capacity—the ability of an estuary to receive nutrients without exhibiting symptoms—also appears to

be important, particularly in the South Atlantic.

Recommended Management Actions. The general

workshop recommendation is for authorities to manage from a watershed perspective, focusing on controllable sources of nutrients and on strategies tailored to individual watershed characteristics in order to maximize potential improvements. This is especially important, given that nutrient-control strategies may not be universally applicable across geographic regions. The individually tailored management plans should also take into account overall

eutrophic conditions and the factors influencing the

level of expression in each estuary, so that efforts

can focus on estuaries that will benefit the most from

nutrient controls. For instance, the 23 estuaries with

high expression of eutrophic conditions and high

susceptibility (which represent about 10% of the national estuarine surface area studied) will likely require greater management efforts and a longer response time for results, than those estuaries with low

susceptibility. In contrast, the 10 estuaries with low

eutrophic conditions and high susceptibility (about

3% of national estuarine area) should be priorities

for preventive management.

On a national basis, the most frequently recommended management targets were agriculture,

wastewater treatment, urban runoff, and atmospheric deposition (Figure 12). Although previous

management efforts have targeted point sources,

they were still one of the top three targets recommended. In all regions except the North Atlantic,

however, nonpoint sources are the primary focus,

representing 60 percent of the recommended targets.

Agriculture was the most frequently recommended

target for the Pacific, Gulf of Mexico, and South Atlantic regions; wastewater treatment plants were important in the North Atlantic; and agriculture and

atmospheric sources were most frequently recommended in the Middle Atlantic. Notable among the

point sources were combined sewer overflows, specifically in the North Atlantic, and wastewater treatment plants in all regions. Of the nonpoint sources,

atmospheric deposition was among the most frequently recommended targets, but was noted almost

exclusively for the Gulf of Mexico and Middle Atlantic regions. Another important nonpoint source

identified as needing management action in the

South Atlantic and Gulf of Mexico were large animal production facilities.

Future Outlook to 2020. At the National

Assessment Workshop, projections were

made to predict what might happen to

U.S. estuaries in the future. The future

outlook was based on predictions of

population growth and expert knowledge of specific management and development activities that are planned

for the watersheds. Past trends were

also considered, to varying degrees,

for this determination (for the most

part, this information was not explicitly dealt with at the Workshop; see

sidebar, page 18). The future outlook

assessment (Figure 13) indicates that

overall eutrophic conditions will

worsen in 86 estuaries, stay the same

in 44, and improve in only eight estuFigure 12. Sources that experts at the National Assessment Workshop identified as

most important targets to manage nutrient inputs

Region

Waste Water Treatment PlantsCombinedSewer Overflow

Onsite Disposal

Industry

Animal Operations

Urban

AgricultureForestryRangeAtmospheric

Pacific 11 0 5 1 0 7 14 3 0 0

Gulf of Mexico 11 0 2 9 5 11 15 1 5 11

South Atlantic 8 0 2 3 4 12 13 5 0 0

Middle Atlantic 8 1 3 0 1 5 12 0 0 12

North Atlantic 11 7 0 0 0 2 1 0 0 1

National 49 8 12 13 10 37 55 9 5 24
17

National Overview

Boston Harbor

Chesapeake Bay Mainstem

Barnegat Bay

Patuxent River

Potomac River Lake 

Pontchartrain

Florida

Bay

Upper Laguna Madre

Baffin Bay

Lower Laguna Madre

Mississippi R.

Plume

Corpus Christi Bay

San Francisco Bay

Tijuana Estuary

San Diego Bay Mission Bay

Newport Bay

San Pedro Bay Anaheim Bay

York River

Tangier/Pocomoke Sounds

New Jersey Inland Bays

St. Croix River/

Cobscook Bay

Bluehill Bay

Damariscotta River

Drakes Estero

Tomales Bay

Puget Sound

 Hood Canal

 Whidbey Basin/Skagit Bay

 S. Puget Sound

 Port Orchard System

Monterey Bay

Albemarle Sound

St. Johns 

River

Calcasieu

Lake

Suwannee 

River

Sarasota Bay

Charlotte Harbor

Caloosahatchee R.

Apalachicola 

Bay

Galveston Bay

Choctawhatchee Bay

Pensacola Bay

Perdido Bay

San Antonio Bay

Charleston Harbor

North Ten Thousand Islands 

South Ten Thousand Islands

Great Bay

Hampton Harbor

Plum Island Sound

Massachusetts Bay

Casco Bay

Rappahannock River

James River

Chester River

Choptank River

Maryland Inland Bays

Chincoteague Bay

Savannah River

Ossabaw Sound

St. Catherines/Sapelo Sounds

St. Andrew/St. Simons Sounds

Biscayne Bay

Altamaha River

St. Marys River/Cumberland Sound Indian River

Broad River

Bogue Sound

New River

St. Helena Sound

Apalachee Bay

St. 

Andrew 

Bay

Breton/

Chandeleur

Sounds

Mermentau 

Estuary

Terrebonne/

Timbalier Bays

Matagorda Bay

Eel River

Bellingham/Padilla/ Samish Bays

Sequim/Discovery 

Bays

Grays Harbor

Willapa Bay

Nehalem River

Tillamook Bay

Netarts Bay

Siletz Bay

Yaquina Bay

Alsea River

Siuslaw River

Umpqua River

Coos Bay

CoquilleRiver

Rogue River

Worsen

Improve

Future Eutrophication Trends (2020)

Conditions Expected To:

Figure 13. Expected trends in eutrophication through 2020 Experts at the National Assessment Workshop determined that conditions are expected to worsen in more than half of the nation’s estuaries, and along all of the coasts, by 2020. However, the experts cautioned that uncertainty is inherent in these predictions and that they may be unduly pessimistic. A number of factors that affect eutrophic conditions may change over time, making it difficult to predict with substantial certainty the ultimate effect of population growth on nutrient loadings and the subsequent expression of eutrophic conditions in estuaries. Each symbol represents expected changes in the ex- pression of eutrophication conditions by 2020. Ab- sence of a symbol indicates no expected change from current conditions. Predictions are based primarily on projected population growth, coupled with suscep- tibility to nutrient inputs.
18

National Overview

The assessment of symptom trends (ca. 1970

to 1995) was based on data from NOAA’s Estuarine Eutrophication Survey. These data are

less certain, and the assessments were less rigorously reviewed at the National Assessment

Workshop. For 51 estuaries, data was insufficient to assess trends.

A greater number of estuaries were reported

to have worsening conditions for chlorophyll

a, epiphytes, macroalgae, nuisance blooms,

toxic blooms, and submerged aquatic vegetation loss, than the number of estuaries for

which conditions improved. For dissolved oxygen, conditions improved in more estuaries

than those that worsened. Overall, eutrophic

conditions worsened in 48 estuaries and improved in 14. In 26 systems, there was no trend

in overall eutrophic conditions since 1970. Most

of the estuaries that showed overall improvement were located in the Gulf of Mexico. The

greatest number of estuaries in which conditions worsened were in the Gulf of Mexico and

Middle Atlantic regions.

Worsening trends have been attributed to a

general increase in population density in estuarine watersheds. Some of these estuaries are

historically rural, with farming and urban development intensifying concurrently. Notably,

recent toxic blooms in the Middle Atlantic and

South Atlantic regions are thought to be linked

to the increase in confined animal operations

and the release of untreated animal wastes into

local water bodies. Successes have also been

reported, with improvements in water quality

over time. These trends are attributed to the

implementation of strategies that primarily

reduce point sources, as mandated by the Clean

Water Act. In addition, some of the National

Estuary Program estuaries, such as Tampa and

Sarasota Bays, are good examples of successful nutrient-reduction strategies that have reversed eutrophic conditions.

Past Trends in Eutrophication

In 17 estuaries, there was insufficient data

to assess overall eutrophic conditions:

Merrimack River

Albemarle Sound

Pamlico Sound

St. Helena Sound

Lake Borgne

Santa Monica Bay

Drakes Estero

Rogue River

Coquille River

Coos Bay

Umpqua River

Siuslaw River

Alsea River

Siletz Bay

Netarts Bay

Tillamook Bay

Nehalem River

aries during the next 20 years. At present, overall

eutrophic conditions are moderate to low in 43 of the

estuaries that are predicted to worsen; conditions are

unknown in 12 additional estuaries predicted to

worsen. The 10 estuaries that currently exhibit low

eutrophic conditions, and are highly susceptible, are

at particular risk of developing worsening conditions

if nutrient inputs increase. Most of the estuaries with

negative outlooks are located in the Pacific and Gulf

of Mexico regions. These predictions tend to mirror

historic trends; over time, more estuaries have experienced worsening conditions.

Data Gaps and Research Needs

The greatest need is for data that better characterize

the levels of eutrophic symptoms in estuaries. For 17

estuaries, there is insufficient information to assess

conditions, and for many more (31), the assessment

reliability is low due to limited or uncertain data. These

estuaries represent 25% of the nation’s estuarine area.

Physical processes and levels of nutrient inputs also

need to be better characterized, so that causal linkages can be made and used to develop appropriate

management plans.

Process-oriented research is needed to improve understanding of the mechanisms involved in the progressive development of eutrophication. For example,

little is known about “thresholds,” such as the level of

nutrient inputs above which toxic blooms will flourish. Research must be done to improve the understanding of historically higher levels of biological grazing

as a controlling mechanism, and of the ways in which

the decline of this mechanism affects the rate of development of eutrophic symptoms. The influence of

phosphorus and other nutrients as contributors to

eutrophication, relative to nitrogen, also needs further

clarification. Climate change, specifically global warming, will affect water levels, circulation, temperature

and salinity, all of which will have an effect on the

susceptibility of estuaries, and, thus, the potential development of symptoms. Finally, the combined effects

of nutrient inputs and other pollutant stressors on the

health of estuaries should be investigated. All of this

information should be used to develop predictive

models that will enhance and ensure effective management actions.
19

This section focuses on five major regions of the coterminous U.S. It highlights regional differences in overall eutrophic conditions; the factors influencing the development of these conditions; the associated impairments to human uses of estuarine resources; the future outlook; and the priorities for management, data and research. Differences between regions occur due to

variations in estuarine susceptibility in combination with the level of nutrient inputs reaching estuarine waters. In some regions, the climate, shoreline structure, coastal topography, and circulation and flushing patterns are similar across the entire

region, and its estuaries respond similarly, for the most part, to nutrient inputs. In other regions, these characteristics vary

greatly among estuaries, and identifiable subregional differences occur in response to inputs. Therefore, in addition to regional

summaries, detailed results are provided for each of the 138 estuaries and the Mississippi River Plume. To facilitate comparison

among the regions, brief descriptions are provided of physical settings, general land-use characteristics and the locations of

major population centers. Also provided are confidence levels for the assessments.

Eutrophic Conditions and Expression of Symptoms.

The overall eutrophic condition is a reflection of the

combined levels of expression of six individual

symptoms: three primary symptoms (chlorophyll a,

epiphyte abundance, and macroalgal abundance)

and three secondary symptoms (dissolved oxygen

conditions, loss of submerged aquatic vegetation,

and the occurrence of nuisance/toxic algal blooms).

Each estuary received an overall rating, as well as

ratings for the level of impact of each individual

symptom. The overall eutrophic condition, and the

level of impact for each individual symptom, are

characterized as high, medium, or low. In addition,

improving symptoms, as indicated by the most recent

trend direction, are noted with an upward-pointing

arrow. A summary table is provided to facilitate comparison of the individual symptom levels with the

overall level of eutrophic condition (Figures 16, 19,

22, 25, 28).

Data Quality. The level of confidence in the assessment of eutrophic conditions was determined for

each estuary characterized in this report and was

based on the temporal and spatial representativeness of the data. Figure 14 illustrates the varying confidence levels among the five regions. There are 17

estuaries for which an assessment of overall

eutrophic condition was not possible due to insufficient information (see box, page 18). Whenever possible, information on individual symptoms was provided for these estuaries.

Factors Influencing Eutrophic Conditions. Participants at the National Assessment Workshop combined nitrogen input estimates with susceptibility

values for each estuary to determine the overall influence of human activities on the development of

eutrophic conditions. The overall human influence

is characterized as high, moderate or low. A summary table facilitates the comparison of individual

and overall influencing factors with the severity of

eutrophic conditions (Figures 17, 20, 23, 26, 29).

Impaired Uses in Estuaries. Experts at the National

Assessment Workshop identified general impairments due to eutrophic conditions within estuaries.

The regional assessments highlight this information.

Future Outlook on Eutrophic Conditions. When considering the outlook for 20 years hence, the experts

reviewed present conditions and inputs, historic conditions and inputs, and projections of future inputs

based primarily on projected population growth.

Each regional map shows the estuaries in which conditions are expected to worsen or develop, and those

in which conditions are expected to improve. In other

estuaries, conditions are expected to remain the

same, or there is insufficient information with which

to make a prediction.

Management Concerns, Data and Research Needs.

Workshop participants identified management targets, data gaps, and research needs for each estuary.

Figure 14. Eutrophication Assessment Confidence Levels

Regional Summaries

5

10

15

20

25

30

35

North 

Atlantic

Middle 

Atlantic

South 

Atlantic

Gulf of 

Mexico

Pacific

Number of Estuaries

Level

High

Medium 

Low

Confidence
20

North Atlantic North Atlantic

2

3

4 5

6

7

8

9

10

11

12

13

14

15

16

17

18

Eutrophic Conditions and Trends

?

?

1. St. Croix R./Cobscook Bay

2. Englishman Bay

3. Narraguagus Bay

4. Blue Hill Bay

5. Penobscot Bay

6. Muscongus Bay

7. Damariscotta River

8. Sheepscot Bay

9. Kennebec/Androscoggin R.

10. Casco Bay

11. Saco Bay

12. Great Bay

13. Hampton Harbor Estuary

14. Merrimack River

15. Plum Island Sound

16. Massachusetts Bay

17. Boston Harbor

18. Cape Cod Bay

1

Figure 15. Level of expression of eutrophic conditions and future trends

More than half of the North Atlantic estuaries have moderate to high eutrophic conditions, as assessed by workshop participants. Only a few, however, have a substantial level of human influence. The major nutrient source for

most North Atlantic estuarine and coastal systems is from offshore coastal waters; consequently, many of the

eutrophic symptoms expressed in the region are thought to be primarily natural conditions, especially for chlorophyll a concentrations and toxic algae. Additionally, the high degree of tidal flushing and low freshwater inputs

characteristic of many of the systems tend to minimize impacts due to human-related nutrient inputs. Future

increases in nutrient inputs are likely to exacerbate some of these naturally occurring conditions.

High: symptoms generally occur periodically and/or over extensive area.

Moderate: symptoms generally occur less periodically and/or over

medium area.

Low: few symptoms occur at more

than minimal levels.

Insufficient data for analysis

Worsen: symptoms are expected to

develop or become more pronounced by 2020.

Improve: symptoms are expected

to decline through 2020.
21

North Atlantic

Eutrophic Conditions

Overall Conditions. Moderate or higher levels of

eutrophic conditions occurred in more than half of

the estuarine systems, with six being in the high category. Estuaries with these conditions were located

along the length of the coast, with estuaries exhibiting low eutrophic conditions interspersed between

them.

Expression of Symptoms. Close to half of the estuaries exhibited at least one of the six symptoms at

high levels. For the primary symptoms, chlorophyll

a was expressed at moderate levels for a majority of

estuaries; macroalgal abundance problems occurred

in almost half of the systems; and epiphyte problems were minimal. For the secondary symptoms,

moderate to high levels of nuisance/toxic blooms

occurred in more than half of the systems; depleted

dissolved oxygen occurred at low levels in more than

half, and losses of submerged aquatic vegetation

were minimal.

In general, for those systems with high eutrophic

conditions, nuisance/toxic algal blooms and overabundance of macroalgae were the principle symptoms contributing to the observed overall condition.

Moderate expression of chlorophyll a and low expression of depleted dissolved oxygen were also observed in most of the systems with high eutrophic

conditions, although these symptoms tended to occur regardless of overall eutrophic condition.

The North Atlantic region includes 18 estuarine systems,

encompassing roughly 2,000 square miles of water surface area. In the northern part of the region, the coastal

shoreline consists mainly of drowned river valleys characterized by numerous small embayments, rocky shoreline, wave-cut cliffs, and large, rocky islands. The southern part of the region contains more cobble, gravel, and

sand beaches, and tidal marshes are more extensive. A

high degree of tidal flushing and low freshwater input are

characteristic of many of these systems. Major population centers, including Portland and Boston, are located

in this southern portion.

Submerged aquatic vegetation improved in a few estuaries, largely due to replanting efforts as well as recovery from wasting disease. In Casco Bay, improvements in levels of dissolved oxygen appeared to be

related to point-source controls and declining Atlantic Menhaden runs.

The confidence levels for the assessment of eutrophic

conditions were low for four estuaries. Information

was sparsest on trends in submerged aquatic vegetation. There are less data for the Merrimack River

estuary than for any other system in the region.

Influencing Factors

Nutrient inputs from human sources are thought to

be high in only three North Atlantic estuarine systems, primarily because freshwater inflow in the region is generally low and drains from watersheds

with sparse populations. Susceptibility to nutrient

inputs is low in most systems because of the dominance of tidal flushing. As a result of the low nutrient inputs and low susceptibility, human influence

is generally very low in the region.

Of the six estuaries exhibiting high eutrophic conFigure 16. Eutrophic conditions and symptoms

The major nutrient source for many

North Atlantic estuarine and coastal

systems is from offshore coastal waters. Consequently, many of the

eutrophic symptoms expressed in the

region, such as toxic algal blooms, are

thought to be primarily natural conditions.

Eutrophic

Condition

Kennebec/Androscoggin Rivers

Chlorophyll a

Estuary

Epiphytes

Macroalgae

Low Dissolved

Oxygen

SAV Loss

Nuisance/

Toxic Blooms

St. Croix River/Cobscook Bay

Englishman Bay

Narraguagus Bay

Blue Hill Bay

Penobscot Bay

Muscongus Bay

Damariscotta River

Sheepscot Bay

Casco Bay

Saco Bay

Great Bay

Hampton Harbor Estuary

Merrimack River

Plum Island Sound

Massachusetts Bay

Boston Harbor

Cape Cod Bay

?

?

?

?

?

?

? ?

? ??? ?

Symptom Expression

Primary Secondary

No 

Expression

High Moderate Low Insufficient 

Data

?

Improving

Symptom
22

North Atlantic

Potential Management Concerns

The most frequently noted nutrient sources to target for management efforts were wastewater treatment plants and combined sewer overflows. Urban

runoff, agriculture, aquaculture, and atmospheric inputs were also identified as sources of concern, but

in relatively few estuaries.

Future Outlook to 2020

By the year 2020, eutrophication symptoms are expected to worsen in about one-third of the systems,

primarily due to increased nutrient inputs from

population increases and the growth of the aquaculture industry. Of these estuaries, St. Croix River/

Cobscook Bay, Great Bay, and Plum Island Sound

are expected to worsen the most. Conversely, Casco

Bay and Boston Harbor are expected to improve, to

a limited extent.

The confidence levels for the assessment of the future outlook was low for two estuaries.

Data Gaps and Research Needs

Several estuaries were identified as requiring better

baseline symptom data, although only four systems

were noted to have low confidence levels for assessment.

Important data and research needs generally include

improved assessments of nutrient inputs from rivers, groundwater, and aquaculture; better understanding of circulation dynamics; and improved estimates of population growth and land use. For systems with seasonal population changes, research is

needed to assess the effects of winter-summer population changes on eutrophic conditions.

ditions, only one, Boston Harbor, had high human

influences. Furthermore, according to expert consensus at the National and Regional Assessment Workshops, offshore coastal waters are the major nutrient source for most estuarine systems in this region.

Consequently, certain eutrophic symptoms, such as

toxic algal blooms, are thought to be primarily natural conditions. Human-related nutrient inputs, however, may exacerbate these natural conditions.

The confidence level of the assessment of anthropogenic influence was low for three estuaries.

Impaired Uses

Very few uses of estuarine resources were identified

as being impaired by eutrophication in this region.

The impaired use of shellfish resources was the most

extensive problem identified; however, shellfish-area

closures were attributed mainly to natural toxic algal blooms, which can lead to paralytic shellfish poisoning in people. Minor problems were also noted

for boating.

Figure 17. Eutrophic conditions and influencing factors Eutrophic Condition

Moderate Low

Overall Human 

Influence

Susceptibility

Nitrogen Input

Englishman Bay

Narraguagus Bay

Blue Hill Bay

Penobscot Bay

Muscongus Bay

Damariscotta River

Sheepscot Bay

Kennebec/Androscoggin Rivers

Casco Bay

Saco Bay

Great Bay

Hampton Harbor Estuary

Plum Island Sound

Massachusetts Bay

Boston Harbor

Cape Cod Bay

Merrimack River

Insufficient 

Data

Estuary

St. Croix River/Cobscook Bay

High

?

?

Influencing Factors
23

North Atlantic

A high degree of tidal flushing and low freshwater input, characteristic of many North Atlantic estuaries, tend to minimize impacts

due to human-related nutrient inputs. Photo courtesy of Miranda Harris, NOAA.
24

Middle Atlantic

1

2

3 4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

1. Buzzards Bay

2. Narragansett Bay

3. Gardiners Bay

4. Long Island Sound

5. Connecticut River

6. Great South Bay

7. Hudson River/Raritan Bay

8. Barnegat Bay

9. New Jersey Inland Bays

10. Delaware Bay

11. Delaware Inland Bays

12. Maryland Inland Bays

13. Chincoteague Bay

14. Chesapeake Bay

15. Patuxent River

16. Potomac River

17. Rappahannock River

18. York River

19. James River

20. Chester River

21. Choptank River

22. Tangier/Pocomoke Sounds

Eutrophic Conditions and Trends

?

High: symptoms generally occur periodically and/or over extensive area.

Moderate: symptoms generally occur less periodically and/or over

medium area.

Low: few symptoms occur at more

than minimal levels.

Insufficient data for analysis

Worsen: symptoms are expected to

develop or become more pronounced by 2020.

Improve: symptoms are expected

to decline through 2020.

Middle Atlantic

Figure 18. Level of expression of eutrophic conditions and future trends

In this region, the expression of high eutrophic conditions is extensive and the level of human influence is high.

Eutrophic symptoms are widespread and likely have substantial impacts on many estuarine natural resources. The

expression of pronounced eutrophic symptoms tends to be more pervasive in enclosed or river-dominated estuaries, while ocean-influenced systems exhibit fewer impacts. There are numerous ongoing efforts to control nutrient

inputs; however, the ecological response to nutrient reductions is often slow in many of these systems, and consequently, the positive effects of these efforts may have yet to materialize. The widespread influence of atmospheric

nutrient sources, together with rapid rates of development, pose a great challenge to the control of nutrient inputs

and eutrophication.
25

Middle Atlantic

Eutrophic Conditions

Overall Conditions. Estuaries with moderate to high

eutrophic conditions were widespread and evenly

spaced throughout the region, with close to half of

the estuarine systems exhibiting high levels of

eutrophic conditions, and an additional five showing moderate conditions.

high expressions of primary symptoms. The five

estuaries exhibiting moderate eutrophic conditions

displayed similar symptoms, except that the secondary symptoms were somewhat less severe.

An improvement in at least one symptom is noted

as the most recent trend in close to half of the estuaries. Unfortunately, most of these improvements are

modest, and follow long periods of declining conditions. Improving trends are a positive sign that management efforts are working; however, where conditions are moderate to high, there is still much room

for improvement, and efforts at nutrient control

should be maintained and fortified. In the Chesapeake Bay and its tributaries, for example, submerged aquatic vegetation suffered severe declines

in the 1960s and 1970s, primarily as the result of nutrient enrichment, and only recently have nutrient

management and other factors contributed to the

slight improvement.

The Middle Atlantic region includes 22 estuarine systems, encompassing more than 7,790 square miles of water surface area. Coastal areas are characterized by irregular shorelines, wide, sandy beaches, numerous barrier island formations, and extensive salt marshes. Tides range

from one to six feet but generally fall within the lower

part of the range. Tidal flushing is most dominant in the

northern part of the region, while freshwater inflow is

more important in the Chesapeake Bay systems. Land use

is characterized by large urban tracts and extensive agricultural areas. Major population centers include Providence, Hartford, New York City, Philadelphia, Baltimore,

Washington, D.C., and Richmond.

Figure 19. Eutrophic conditions and symptoms

The expression of severe eutrophic

conditions tends to be more pervasive

in enclosed or river-dominated estuaries, while the more ocean-influenced

systems experience fewer impacts.

Expression of Symptoms. Well over half of the estuaries exhibited at least one of the six symptoms at

high levels. Of the primary symptoms, chlorophyll

a had the most pronounced expression, with high

levels in half of the estuaries and moderate levels in

the rest. Macroalgal abundance problems occurred

in 10 estuaries, and in five of these at moderate to

high levels. Epiphyte abundance problems occurred

in more than one-quarter of the estuaries. Extensive

expressions of secondary symptoms were also noted

in the region. Depleted dissolved oxygen occurred

in every estuary, although it tended to be expressed

at low levels. Both submerged aquatic vegetation

loss and nuisance/toxic algal blooms were problems

in more than half of the estuaries, primarily occurring at moderate to high levels.

There did not appear to be a single symptom dominating the overall expression of high eutrophic conditions. Rather, there was a wide and varied array

of symptoms contributing to the overall conditions

observed. The 10 estuaries exhibiting high eutrophic

conditions had varying combinations of low dissolved oxygen, submerged aquatic vegetation loss,

and nuisance/toxic algal blooms. In most of these

estuaries, these secondary symptoms coincided with

Eutrophic 

Condition

Symptom Expression

Chlorophyll a

Estuary

Epiphytes

Macroalgae

Low Dissolved 

Oxygen

SAV Loss

Nuisance/

Toxic Blooms

Buzzards Bay

Narragansett Bay

Gardiners Bay

Long Island Sound

Connecticut River

Great South Bay

Hudson River/Raritan Bay

Barnegat Bay

New Jersey Inland Bays

Delaware Bay

Delaware Inland Bays

Maryland Inland Bays

Chincoteague Bay

Chesapeake Bay (mainstem)

Patuxent River

Potomac River

Rappahannock River

York River

James River

Chester River

Choptank River

Tangier/Pocomoke Sounds

?

?

?

?

?

?

? ? ?

? ?

Primary Secondary

No 

Expression

High Moderate Low Insufficient 

Data

?

Improving

Symptom
26

Middle Atlantic

The confidence levels for the assessment of eutrophic

conditions were generally high, although three estuaries were rated as low. The Connecticut River had

the least data and the lowest confidence. Information was sparsest for trends in epiphyte abundance.

Influencing Factors

The expression of severe eutrophic conditions

tended to be more pervasive in enclosed or riverdominated estuaries, such as the Chesapeake Bay

and its tributaries and the Delaware Inland Bays,

while ocean-influenced systems, such as Buzzards

Bay and Delaware Bay, exhibited fewer impacts (although these systems may have had small, more localized areas of high symptoms). Nitrogen inputs

were moderate to high in 15 estuaries, and susceptibility was moderate to high in all systems. Accordingly, human influence was considered to be extremely strong in this region. Of the 15 estuaries with

moderate to high eutrophic conditions, 12 also exhibited high human influence.

Additionally, several systems displayed minimal

eutrophic conditions despite a substantial level of

human influence. It is possible that some of these

systems are close to developing full-scale eutrophic

symptoms. Alternatively, some of the systems may

not be as susceptible as the data indicated, or the

estimates of nitrogen inputs may have been too high.

The confidence levels for the assessment of overall

human influence were generally high; three estuaries were rated as low.

Impaired Uses

The loss of habitat (primarily submerged aquatic

vegetation) was the most cited impaired use (15 estuaries), followed closely by degradation of recreational and commercial fishing (12 estuaries). Shellfish resources, swimming, and aesthetic values were

impaired in a moderate number of estuaries, while

tourism and boating were affected to a small extent.

Almost all impaired uses occurred in systems in

which eutrophic symptoms were moderate or high.

Potential Management Concerns

The most important sources to target to manage

nutrient inputs in the region were identified as atmospheric inputs, agricultural runoff, and discharges from wastewater treatment plants. Urban

runoff, septic systems, combined sewer overflows,

and animal operations were also noted as important

targets, but in fewer estuarine basins.

Future Outlook to 2020

Eutrophication conditions are expected to worsen

slightly in 10 estuaries, and to worsen more severely

in three. In eight systems (primarily those from Buzzards Bay south through Delaware Bay), no substantial changes are predicted. Great improvement is not

expected in any of the region’s estuaries.

The confidences levels for the assessment of the future outlook was low for four estuaries. The reliability of all of this information is, however, inherently

vulnerable to unforeseen changes.

Figure 20. Eutrophic conditions and influencing factors Eutrophic Condition

Moderate Low

Overall Human 

Influence

Susceptibility

Nitrogen Input

Insufficient 

Data

Estuary

High ?

Chesapeake Bay

Barnegat Bay

Delaware Inland Bays

Patuxent River

Potomac River

Tangier/Pocomoke Sounds

Long Island Sound

York River

Great South Bay

Gardiners Bay

Rappahannock River

Hudson River/Raritan Bay

Chester River

Choptank River

Maryland Inland Bays

Narragansett Bay

New Jersey Inland Bays

Delaware Bay

James River

Connecticut River

Chincoteague Bay

Buzzards Bay

Influencing Factors
27

Middle Atlantic

Data Gaps and Research Needs

Better quantification of nutrient sources, especially

from the atmosphere and groundwater, is needed

to determine a more accurate assessment of nutrient loading pressures. A major research need for this

region is a concrete determination of, and a more

definitive knowledge of, the relationship between

the human factors that influence eutrophication and

the quality and quantity of living marine resources

in the estuaries. This will entail clarifying and quantifying water-quality pathways; that is, both humanrelated and naturally occurring nutrient inputs, and

the nature of their cascading effects throughout the

trophic levels of the various estuarine systems.

This dense bloom of cyanobacteria (blue-green algae) occurred in the Potomac River estuary downstream of Washington, D.C.

Photo courtesy of W. Bennett, U.S. Geological Survey.
28

South Atlantic

1. Albemarle Sound

2. Pamlico Sound

3. Pamlico/Pungo Rivers

4. Neuse River

5. Bogue Sound

6. New River

7. Cape Fear River

8. Winyah Bay

9. N. Santee/S. Santee Rivers

10. Charleston Harbor

11. Stono/North Edisto Rivers

12. St. Helena Sound

13. Broad River

14. Savannah River

15. Ossabaw Sound

16. St. Catherines/Sapelo Sounds

17. Altamaha River

18. St. Andrew/St. Simons Sounds

19. St. Marys River/Cumberland Sound

20. St. Johns River

21. Indian River

22. Biscayne Bay

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

Eutrophic Conditions and Trends

?

?

?

?

South Atlantic

Figure 21. Level of expression of eutrophic conditions and future trends

High: symptoms generally occur periodically and/or over extensive area.

Moderate: symptoms generally occur less periodically and/or over

medium area.

Low: few symptoms occur at more

than minimal levels.

Insufficient data for analysis

Worsen: symptoms are expected to

develop or become more pronounced by 2020.

Improve: symptoms are expected

to decline through 2020.

High eutrophic conditions occur mostly in the northern and southern parts of this region. These conditions are

indicated mainly by high expressions of chlorophyll a, harmful algal blooms, and low dissolved oxygen levels.

More than half of the estuaries exhibiting minimal eutrophic conditions are likely to develop more pronounced

symptoms due to increased nutrient loading. In the affected estuaries, fishing, fish consumption, and shellfish

resources are identified as impaired uses. Important sources identified as management concerns are wastewater

treatment plants, large animal operations, and other agricultural activities. Urban and forestry sources will become more important as efforts are made to minimize future degradation, especially in systems that currently

exhibit few impacts.
29

South Atlantic

The South Atlantic region includes 22 estuaries, encom- Figure 22. Eutrophic conditions and symptoms

passing more than 4,440 square miles of water surface

area. The region is comprised of extensive barrier and sea

islands that parallel the shoreline. The coastal environment consists of shallow lagoonal estuaries, extensive tidal

marshes and drowned river valleys. Estuarine circulation patterns are dominated mainly by wind and seasonal

freshwater inflow in North Carolina, and mainly by freshwater inflow and tides in South Carolina and Georgia.

Estuarine circulation along the Florida coast is dominated

by wind forcing and human engineering. Tidal range

throughout the region is moderately low to high (1.5-7.0

feet) and influences mixing in the water column, primarily near the inlets. The dominant land uses are agriculture and industry, and, to a lesser extent, forestry. Major

population centers include Miami, Jacksonville, and Savannah.

Eutrophic Conditions

Overall Conditions. The South Atlantic region contains only four estuarine systems characterized as

having high levels of eutrophic conditions: the Neuse

River, Pamlico/Pungo Rivers, New River, and the

St. John’s River. Most of the other systems were relatively unaffected. Nevertheless, almost half of the

region’s estuaries exhibited eutrophic conditions at

low to moderate levels. Most of these estuaries are

in South Carolina and Georgia.

Expression of Symptoms. In five estuaries, at least

one of the six individual symptoms was expressed

at high levels. Of the primary symptoms, chlorophyll

a had the most pronounced expression in five estuaries located in North Carolina and Florida. Of the

secondary symptoms, depleted dissolved oxygen

was considered high only in the Neuse River; however, low to moderate conditions occurred in almost

every other estuary in the region. Nuisance/toxic

algal blooms occurred at high levels in both the New

and Neuse Rivers and at moderate levels in the

Pamlico/Pungo Rivers of North Carolina. The loss

of submerged aquatic vegetation was a problem in

almost half of the estuaries, but mainly at low to

moderate levels.

In general, the symptoms most often associated with

high expressions of eutrophic conditions were high

chlorophyll a and nuisance/toxic algal blooms, although various levels of other symptoms were

known to occur.

Some data existed for the Albemarle and Pamlico

Sounds, but it was for very limited portions of the

systems. St. Helena Sound also had insufficient data

for an overall assessment. In 10 other estuaries, the

confidence levels for assessments were low. Information was sparsest for trends in submerged aquatic

vegetation.

Influencing Factors

The overall level of human influence was low in half

of the region’s estuaries, especially in South Carolina and Georgia, and moderate in most of the remaining estuaries. Human influence was most pronounced in the Pamlico/Pungo Rivers, the Neuse

River and the New River.

While few estuaries in the South Atlantic exhibit high eutrophic conditions, many estuaries have moderate

to high susceptibility. Furthermore,

conditions are expected to worsen in

10 estuaries that currently exhibit low

to moderate eutrophic conditions.

Eutrophic 

Condition

Symptom Expression Chlorophyll a

Estuary

Epiphytes

Macroalgae

Low Dissolved

Oxygen

SAV Loss

Nuisance/

Toxic Blooms

Albemarle Sound

Pamlico Sound

Pamlico/Pungo Rivers

Neuse River

Bogue Sound

New River

Cape Fear River

Winyah Bay

N. Santee/S. Santee Rivers

Charleston Harbor

Stono/North Edisto Rivers

St. Helena Sound

Broad River

Savannah River

Ossabaw Sound

St. Catherines/Sapelo Sounds

Altamaha River

St. Andrew/St. Simons Sounds

St. Marys River/Cumberland Sd.

St. Johns River

Indian River

Biscayne Bay

?

?

? ?

?

?

? ?

?

?? ??

?? ?

?

Primary Secondary

?

No 

Expression

High Moderate Low Insufficient 

Data

?

Improving

Symptom
30

South Atlantic

Figure 23. Eutrophic conditions and influencing factors

Many factors influence the expression of eutrophic

conditions in South Atlantic estuaries. The limited

number of systems in which eutrophic conditions

were high generally had restricted circulation, low

tidal exchange, and moderate to high nitrogen inputs. In most of the other estuaries, which were relatively unaffected by eutrophication, the influence of

tidal marshes (which act as a nutrient filtering

mechanism), strong tides, and low nitrogen inputs

combined to keep eutrophic conditions at bay.

The confidence levels for the assessment of overall

human influence were low in 10 estuaries.

Impaired Uses

Although impaired uses in the South Atlantic were

difficult to relate directly to eutrophic conditions,

results from the National Assessment Workshop did

suggest that the most important impaired uses occurring in the region were commercial and recreational fishing, shellfishing, and fish consumption.

Swimming, boating and tourism were also affected,

to a lesser extent.

Potential Management Concerns

The areas requiring specific management focus are

driven by dominant land-use practices around the

estuaries with problematic conditions. For the systems with the most pronounced expressions of

eutrophication, the most important nutrient sources

to focus on are wastewater treatment plants, large

animal operations, and agricultural activities. In estuaries with intermediate to low eutrophic symptoms, management efforts to control nutrients from

urban, agricultural, and, to a lesser extent, forestry

sources, will minimize further degradation.

Future Outlook to 2020

Based on the experts’ knowledge of watershed activities, population trends, and nutrient-loading estimates, 12 estuaries were predicted to develop worsening eutrophication conditions through 2020; at

present, more than half of these systems are relatively pristine and as yet unaffected by eutrophication. Coastal Georgia and South Carolina were projected to have the greatest relative population growth

of all coastal regions in the nation, and thus, despite

moderate to low symptoms at present, the likelihood

that these estuaries will develop future problems is

inordinately high. In fact, the first red tide blooms

ever reported in South Carolina and Georgia occurred in June 1999. Estuaries that currently exhibit

moderate to high levels of eutrophication, and that

were predicted to develop worsening conditions, are

Charleston Harbor, the Savannah River, St. Marys

River, St. Johns River, and the Indian River. Bogue

Sound, the New River, and St. Helena Sound were

noted as potentially showing improvement in the

future.

The confidence levels for the assessment of the future outlook were low for three estuaries and moderate for the rest. The reliability of all of this information is, however, inherently vulnerable to unforeseen changes.

Data Gaps and Research Needs

The South Atlantic is generally a poorly studied region. The confidence level of the assessment of overall eutrophic condition was low for 12 systems, and

an additional six were specifically identified as requiring improvements in basic monitoring. The need for

data in this region is critical, given the projected increases in population and the susceptibility of many

Eutrophic 

Condition

Moderate Low

Overall Human 

Influence

Susceptibility

Nitrogen Input

Insufficient 

Data

Estuary

High ?

Neuse River

Pamlico Sound

Pamlico/Pungo Rivers

New River

St. Johns River

Cape Fear River

Charleston Harbor

Indian River

St. Marys River/Cumberland Sound

Savannah River

Winyah Bay

Stono/North Edisto Rivers

N. Santee/S. Santee Rivers

Broad River

St. Catherines/Sapelo Sounds

St. Andrew/St. Simons Sounds

Bogue Sound

Ossabaw Sound

Altamaha River

Biscayne Bay

St. Helena Sound ?

Albemarle Sound ?

?

?

?

Influencing Factors

?
31

South Atlantic

of the systems. Other identified needs were better data

on organic as well as inorganic nutrient loads and concentrations; time-series data sets in both impacted and

pristine systems; and more data on the comparative

roles of shallow intertidal habitats and water-column

processes. Research on the effects of nutrient loading

in blackwater systems, and comparative data on nutrient processing in blackwater versus alluvial rivers,

were also deemed imperative.

Population growth and the associated development of relatively pristine estuarine watersheds is a major concern for the South Atlantic.

Photograph courtesy of Michael A. Mallin, Center for Marine Science Research, University of North Carolina at Wilmington.
32

Gulf of Mexico

1. Florida Bay

2. S. Ten Thousand Islands

3. N. Ten Thousand Islands

4. Rookery Bay

5. Charlotte Harbor

6. Caloosahatchee River

7. Sarasota Bay

8. Tampa Bay

9. Suwannee River

10. Apalachee Bay

11. Apalachicola Bay

12. St. Andrew Bay

13. Choctawhatchee Bay

14. Pensacola Bay

15. Perdido Bay

16. Mobile Bay

17. East Mississippi Sound

18. West Mississippi Sound

19. Lake Borgne

20. Lake Pontchartrain

21. Breton/Chandeleur Sounds

22. Mississippi River

23. Barataria Bay

24. Terrebonne/Timbalier Bays

25. Atchafalaya/Vermilion Bays

26. Mermentau Estuary

27. Calcasieu Lake

28. Sabine Lake

29. Galveston Bay

30. Brazos River

31. Matagorda Bay

32. San Antonio Bay

33. Aransas Bay

34. Corpus Christi Bay

35. Upper Laguna Madre

36. Baffin Bay

37. Lower Laguna Madre

38. Mississippi River Plume

1

2

3

4

5 6

7

8

9

10

11

12 17 16 15 14 13

18

19

20

21

22 23

24

25 26 28 27

29

30

31

32

33

34

36 35

37

38

Eutrophic Conditions and Trends

?

?

The expression of high eutrophic conditions is extensive, and human influence is substantial, in the Gulf of Mexico

region. Although there is a great diversity of estuary types, common characteristics, such as low tidal flushing,

warm water, and long algal growing seasons, create conditions that make many of the region’s estuaries susceptible to eutrophic problems. The most significant symptoms in the overall expression of eutrophic conditions are

low dissolved oxygen and loss of submerged aquatic vegetation. Impaired resource uses are evident in many, but

not all, of the affected systems. Conditions are expected to worsen in more than half of the estuaries by 2020.

Gulf of Mexico

Figure 24. Level of expression of eutrophic conditions and future trends

High: symptoms generally occur periodically and/or over extensive area.

Moderate: symptoms generally occur less periodically and/or over

medium area.

Low: few symptoms occur at more

than minimal levels.

Insufficient data for analysis

Worsen: symptoms are expected to

develop or become more pronounced by 2020.

Improve: symptoms are expected

to decline through 2020.
33

Gulf of Mexico

The Gulf of Mexico region includes 37 estuaries plus the Figure 25. Eutrophic conditions and symptoms

Mississippi River Plume, encompassing more than 24,000

square miles of water surface area. The region is comprised of a gently sloping, lowland area as part of the Gulf

Coastal Plain. Estuarine and coastal environments are

highly diverse, consisting of unrestricted open bays, semienclosed lagoons, tidal marshes and delta complexes. The

fresh water that flows naturally into estuaries can fluctuate greatly in the Gulf, and depends on seasonal rainfall patterns. Estuarine circulation patterns are generally wind driven, and coastal waters are usually warmer

than in other regions due to the subtropical climate. Estuaries have fairly low tidal energy (0.5-3.5 ft. tide range),

and water depths are typically shallow when compared to

estuaries in other regions. Land-use activity in the watersheds is typically dominated by agricultural practices.

Major population centers include Houston, New Orleans

and Tampa.

Eutrophic Conditions

Overall Conditions. The Gulf of Mexico was significantly affected by elevated expressions of

eutrophication. Almost half of the estuaries were

characterized as having high levels of eutrophic conditions. Estuaries noted as having the highest-level

conditions were Florida Bay, Lake Pontchartrain,

Calcasieu Lake, the Mississippi River Plume, Corpus Christi Bay and the Laguna Madre system. Fourteen estuaries were characterized as having moderate levels of eutrophic conditions, and only six were

characterized as having low-level conditions.

Expression of Symptoms. In 20 estuaries, at least

one of the six individual symptoms was expressed

at high levels. Of the primary symptoms, chlorophyll a

was expressed at high levels in 12 estuaries that were

located mainly on the coasts of western Florida,

Louisiana and lower Texas. In eight estuaries, epiphytes were considered moderate to high; in seven

estuaries, magroalgal abundance was considered

moderate to high. Of the secondary symptoms, low

dissolved oxygen occurred at high levels in four estuaries, mainly along the Florida coast and in the

Mississippi River Plume. The loss of submerged

aquatic vegetation was a problem in almost half of

the estuaries, but usually at low to moderate levels.

Nuisance/toxic algal blooms also tended to be perOf all regions, the Gulf of Mexico has

the greatest percentage of estuaries

with high eutrophic conditions, despite low to moderate nutrient inputs.

In addition to the prevalence of moderate to high susceptibility, the generally long growing season and warm

waters result in higher levels of expression of eutrophic conditions.

Eutrophic

Condition

Symptom Expression Chlorophyll a

Estuary

Epiphytes

Macroalgae

Low Dissolved

Oxygen

SAV Loss

Nuisance/

Toxic Blooms

Florida Bay

South Ten Thousand Islands

North Ten Thousand Islands

Rookery Bay

Charlotte Harbor

Caloosahatchee River

Sarasota Bay

Tampa Bay

Suwannee River

Apalachee Bay

Apalachicola Bay

St. Andrew Bay

Choctawhatchee Bay

Pensacola Bay

Perdido Bay

Mobile Bay

East Mississippi Sound

West Mississippi Sound

Lake Borgne

Lake Pontchartrain

Breton/Chandeleur Sounds

Mississippi River

Barataria Bay

Terrebonne/Timbalier Bays

Atchafalaya/Vermilion Bays

Mississippi River Plume

Mermentau Estuary

Calcasieu Lake

Sabine Lake

Galveston Bay

Brazos River

Matagorda Bay

San Antonio Bay

Aransas Bay

Corpus Christi Bay

Upper Laguna Madre

Baffin Bay

Lower Laguna Madre

?

?

?

? ?

??? ?

? ?

?

Primary Secondary

No 

Expression

High Moderate Low Insufficient 

Data

?

Improving

Symptom
34

Gulf of Mexico

vasive, occurring in 28 estuaries, eight of which Figure 26. Eutrophic conditions and influencing factors

showed high levels. All eight of these estuaries were

located in the coastal systems of Florida, western

Louisiana and the lower Texas coast.

In the systems with high eutrophic conditions, the

symptoms that generally contribute the most to the

observed overall condition were the loss of submerged aquatic vegetation, increased turbidity associated with high concentrations of chlorophyll a,

and low levels of dissolved oxygen. Moderate to

high levels of nuisance/toxic algal blooms and epiphyte abundance were also major factors in systems

with pronounced expressions of eutrophication.

In general, recent improving trends are due primarily to better management of point and nonpoint

nutrient sources. Where conditions are moderate to

high, however, there is still much room for improvement, and efforts to control nutrient inputs should

be maintained and fortified.

The Gulf of Mexico is generally a well studied region; the confidence levels for the assessment of

overall eutrophic conditions were medium to high

for 31 systems. The confidence levels for the assessment of overall eutrophic conditions were low for

only six systems. Data availability was generally

very good; Lake Borgne was the only estuary with

insufficient data for an assessment.

Overall Human Influence

The overall level of human influence was high in

more than half of all Gulf systems and corresponded

well with high levels of eutrophic conditions (Figure 27). Human influence was considered most

prominent in the Mississippi River Plume, Lake

Pontchartrain, Upper and Lower Laguna Madre, and

Baffin Bay. Noted for having relatively low human

influence were Rookery Bay, the Suwannee River,

Apalachee Bay, and Breton/Chandeleur Sounds.

Many factors influenced the expression of eutrophication in Gulf estuaries. The following influencing

factors were generally associated with moderate to

pronounced levels of expression: low tidal energy,

low flushing rates with increased nutrient inputs,

and low dissolved oxygen levels generally due to

warmer waters and the longer growing season.

These factors contributed significantly to the high

levels of human influence in many Gulf estuaries

with pronounced eutrophic conditions, even though

nitrogen inputs were generally moderate (Figure 27).

For example, although population density is relatively low in the Baffin Bay and Upper Laguna

Madre watersheds, human influence is magnified

Eutrophic 

Condition

Moderate Low

Overall Human 

Influence

Susceptibility

Nitrogen Input

Insufficient 

Data

Estuary

High ?

Lake Pontchartrain

Baffin Bay

Upper Laguna Madre

Lower Laguna Madre

Calcasieu Lake

Corpus Christi Bay

Caloosahatchee River

Charlotte Harbor

Sarasota Bay

Tampa Bay

Choctawhatchee Bay

Perdido Bay

Apalachicola Bay

Pensacola Bay

Sabine Lake

Galveston Bay

San Antonio Bay

Matagorda Bay

St. Andrew Bay

Mobile Bay

East Mississippi Sound

Lake Borgne

Terrebonne/Timbalier Bays

Atchafalaya/Vermilion Bays

Brazos River

Aransas Bay

Suwannee River

West Mississippi Sound

Mississippi River

Apalachee Bay

Breton/Chandeleur Sounds

Mermentau Estuary

Barataria Bay

?

Mississippi River Plume ? ?

Florida Bay ?

South Ten Thousand Islands ?

North Ten Thousand Islands ?

Rookery Bay ?

Influencing Factors
35

Gulf of Mexico

due to these estuaries’ high susceptibility.

The confidence level in the assessment of human influence was low for 11 estuaries.

Impaired Uses

Impaired uses were difficult to define as being directly related to eutrophication. Results from the

Workshop, however, did suggest that the most impaired uses were recreational and commercial fishing and shellfishing. Habitat-level impacts, such as

the loss of submerged aquatic vegetation, were also

noted.

Potential Management Concerns

The areas requiring specific management focus are

driven by agriculture, which is the dominant land

use in the region’s watersheds. Management target

areas are diverse because of the varied physical

makeup and forcing mechanisms that drive conditions in the estuaries. Wastewater treatment plants,

industrial discharges, and agricultural practices are

common management targets. Atmospheric inputs

are important in low-flow systems. Upland inputs

should be targeted for large fluvial systems such as

the Mississippi, Mobile, and Apalachicola Rivers.

Future Outlook to 2020

Of the 38 Gulf estuaries studied, 23 were predicted

to develop worsening conditions over the next 20

years, six of them to a high degree (Mississippi River

Plume, Lake Pontchartrain, Corpus Christi Bay,

Upper and Lower Laguna Madre, and Baffin Bay).

Florida Bay, Breton/Chandeleur Sounds, and

Mermentau Estuary were noted as potentially showing signs of future improvement. The level of confidence for the assessment of the future outlook was

low for 12 estuaries.

Data Gaps and Research Needs

Research areas, such as biogeochemical cycling and

nutrient budget analyses, require an understanding

of the processes by which elements are recycled

within estuaries. According to the experts, these processes are poorly understood and in need of more

attention. Participants at the workshop noted that

phosphorus may be an important contributor to

eutrophication in some Gulf of Mexico estuaries;

however, the relative roles of nitrogen and phosphorus need clarification. The experts also called for

better understanding of individual estuaries’ assimilative capacity, and more research on inlet circulation and approaches to inlet management.

In Florida Bay, this macroalgae bloom smothered the surrounding submerged aquatic vegetation.

Photograph courtesy of Brian LaPointe, Harbor Branch Oceanographic Institute.
36

Pacific

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

1. Tijuana Estuary

2. San Diego Bay

3. Mission Bay

4. Newport Bay

5. San Pedro Bay

6. Alamitos Bay

7. Anaheim Bay

8. Santa Monica Bay

9. Morro Bay

10. Monterey Bay

11. Elkhorn Slough

12. San Francisco Bay

13. Central San Francisco/

 San Pablo/Suisun Bays

14. Drakes Estero

15. Tomales Bay

16. Eel River

17. Humboldt Bay

18. Klamath River

19. Rogue River

20. Coquille River

21. Coos Bay

22. Umpqua River

23. Siuslaw River

24. Alsea River

25. Yaquina Bay

26. Siletz Bay

27. Netarts Bay

28. Tillamook Bay

29. Nehalem River

30. Columbia River

31. Willapa Bay

32. Grays Harbor

33. Puget Sound

34. Hood Canal

35. Whidbey Basin/Skagit Bay

36. South Puget Sound

37. Port Orchard System

38. Bellingham/Padilla/Samish Bays

39. Sequim/Discovery Bays

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30 31

32

33

35

34

36

37

38

39

Eutrophic Conditions and Trends

?

?

?

?

?

?

?

?

?

?

?

?

?

Pacific

Figure 27. Level of expression of eutrophic conditions and future trends

High eutrophic conditions occur in the extreme north and south of the region, and on the central California coast.

These estuaries tend to have restricted circulation and high nutrient inputs. Symptoms are expected to develop or

worsen in the majority of systems, primarily due to projected population increases and development pressures.

Estuarine habitats and shellfisheries are the most affected resources. In general, the most important nutrient

sources for management concern are agriculture, forestry, wastewater treatment plants, and urban runoff. The

assessment confidence is generally low, except in San Francisco Bay and Puget Sound.

High: symptoms generally occur periodically and/or over extensive area.

Moderate: symptoms generally occur less periodically and/or over

medium area.

Low: few symptoms occur at more

than minimal levels.

Insufficient data for analysis

Worsen: symptoms are expected to

develop or become more pronounced by 2020.

Improve: symptoms are expected

to decline through 2020.
37

Pacific

The Pacific region includes 39 estuaries, encompassing Figure 28. Eutrophic conditions and symptoms

more than 2,750 square miles of water surface area. The

region consists of a relatively straight and uninterrupted

shoreline with rocky shores, sandy beaches and occasional

river outlets. Limited areas of flat, lowland environments

support estuaries, bays and lagoons. Estuaries are typically small and separated by large distances. Estuarine

circulation patterns are dominated mainly by seasonal

freshwater inflow in Southern California and by freshwater inflow and tides in the larger estuaries of central

California and Washington state. The tidal range is moderately high (5.0-7.5 feet). Forestry, agriculture and industry are the dominant land uses in the region’s watersheds. Some of the major population centers include Los

Angeles, San Diego, San Francisco and Seattle.

Eutrophic Conditions

Overall Conditions. Pacific Coast estuaries exhibited a wide range of eutrophic conditions. High-level

conditions occurred in seven estuaries, mainly in the

northern and southern sections of the region (Figure 29). Among these were Tijuana Estuary, Newport Bay, and San Francisco Bay. Eleven estuaries

fell into the moderate range; these were interspersed

throughout California and the Pacific Northwest.

Nine estuaries were relatively unaffected by

eutrophic conditions.

Expression of Symptoms. In 19 estuaries, at least

one of the six individual symptoms was expressed

at high levels. Of the primary symptoms, chlorophyll

a was expressed at high levels in 11 systems, most of

them in Southern California and northern Washington. Macroalgal abundance was observed at moderate to high levels in 13 estuaries, most of them also

found in Southern California and Washington. Epiphyte abundance was minimal. Eight estuaries exhibited losses in submerged aquatic vegetation; two

of these at high levels. Nuisance/toxic algal blooms

occurred in 21 estuaries, 12 of which were in the

moderate to high range.

In general, the symptoms contributing most to high

eutrophic conditions were elevated levels of chloroThe Pacific region, more than any

other, is characterized by insufficient

data. Although the estuaries with unknown conditions are generally perceived to have few eutrophic problems, many have moderate susceptibility and are predicted to develop

eutrophic symptoms by 2020.

Eutrophic 

Condition

Symptom Expression Chlorophyll a

Estuary

Epiphytes

Macroalgae

Low Dissolved

Oxygen

SAV Loss

Nuisance/

Toxic Blooms

Tijuana Estuary

Mission Bay

Newport Bay

San Pedro Bay

Monterey Bay

Elkhorn Slough

San Francisco Bay

Central San Francisco/

San Pablo/Suisun Bays

Eel River

Humboldt Bay

Klamath River

Yaquina Bay

Columbia River

Willapa Bay

Puget Sound

San Diego Bay

Alamitos Bay

Anaheim Bay

Santa Monica Bay ?

Morro Bay

Drakes Estero ?

Tomales Bay

Rogue River ?

Coquille River ?

Coos Bay ?

Umpqua River ?

Siuslaw River ?

Alsea River ?

Siletz Bay ?

Netarts Bay ?

Tillamook Bay ?

Nehalem River ?

Grays Harbor

Hood Canal

Whidbey Basin/Skagit Bay

South Puget Sound

Port Orchard System

Bellingham/Padilla/

Samish Bays

Sequim/Discovery Bays

? ?

?

? ?

?? ?

? ?

?? ? ? ?

?

??? ?

? ? ?

?

?? ??

?? ?

?? ?

?? ? ??

?? ?

?? ?

?? ?

?

?? ?

?? ?

? ?

?

?

? ?

Primary Secondary

No 

Expression

High Moderate Low Insufficient 

Data

?

Improving

Symptom
38

Pacific

phyll a, coupled with various combinations of Figure 29. Eutrophic conditions and influencing factors

macroalgal abundance, nuisance/toxic algal blooms,

and low dissolved oxygen. High chlorophyll a concentrations is also a fairly common natural condition in some North Pacific estuaries due to naturally

occurring seasonal blooms.

Recent improvements in certain symptoms were primarily attributed to point source controls and hydrologic changes.

The confidence levels for the assessment of eutrophic

conditions was generally low in this region. Of the

27 estuaries that were characterized, 11 had low confidence levels. Twelve estuaries, most of them in Oregon, had insufficient data for an assessment of conditions. Part of the reason for the paucity of data,

however, is that eutrophication generally is not perceived to be a problem in these systems.

Overall Human Influence

In general, estuaries with high-level eutrophic conditions also had high levels of human influence (Figure 30). Human influence on the expression of

eutrophic symptoms was most pronounced in the

Tijuana Estuary, Newport Bay, San Pedro Bay, Anaheim Bay and San Francisco Bay. Three of these—

Newport, Anaheim and San Pedro—are among the

top 10 U.S. estuaries with respect to population density in the watershed. Tijuana Estuary is also notable

because three-quarters of the watershed is located

in Mexico, making management an international

challenge. The Tijuana River is the primary source

of freshwater to the estuary; it is also a source of

untreated sewage from the city of Tijuana.

Although 12 estuaries had insufficient data for an

assessment of eutrophic conditions, these systems

were generally small, with good flushing capabilities, and nutrient loading appeared to be moderate.

In general, restricted circulation and moderate to

high levels of nutrient inputs were noted as the principle factors contributing to elevated eutrophic

symptoms in Pacific Coast systems.

The level of confidence in the assessment of overall

human influence was low for 30 estuaries.

Impaired Uses

The uses most often cited as impaired were fishing,

shellfishing, swimming and aesthetic value. Most of

these responses addressed the estuaries of Southern

California and Washington; impaired uses were unknown in Oregon and northern California.

Eutrophic 

Condition

Moderate Low

Overall Human 

Influence

Susceptibility

Nitrogen Input

Insufficient 

Data

Estuary

High ?

?

?

Tijuana Estuary

Newport Bay

San Francisco Bay

Elkhorn Slough

Tomales Bay

Hood Canal

South Puget Sound

Port Orchard System

Anaheim Bay

San Diego Bay

Morro Bay

Whidbey Basin/Skagit Bay

Bellingham/Padilla/

Samish Bays

Sequim/Discovery Bays

Willapa Bay

Grays Harbor

Puget Sound

Central San Francisco/

San Pablo/Suisun Bays

San Pedro Bay

Mission Bay

Humboldt Bay

Eel River

Monterey Bay

Yaquina Bay

Klamath River

Columbia River

Alamitos Bay

Santa Monica Bay

Drakes Estero

Coos Bay

Siuslaw River

Tillamook Bay

Rogue River

Alsea River

Netarts Bay

Nehalem River

Coquille River

Umpqua River

Siletz Bay ?

?

?

?

?

?

?

?

?

?

?

?

?

?

Influencing Factors
39

Pacific

Potential Management Concerns

Potential sources to target to improve conditions in

Washington estuaries are wastewater treatment

plants, on-site animal operations, agriculture and

forestry. In Southern California, wastewater treatment plants, urbanization, agriculture and forestry

were cited.

With the exception of three estuaries—San Francisco

Bay, Central San Francisco Bay and the Columbia

River—experts noted that reductions in nutrient inputs would significantly improve water-quality conditions. Workshop participants also recommended

that management efforts focus primarily on the

coastal portions of the watersheds.

Future Outlook to 2020

Thirty-one estuaries were predicted to develop worsening conditions during the next 20 years. Five of

these—Tijuana Estuary, San Diego Bay, Newport Bay,

Hood Canal and South Puget Sound—are expected

to get much worse. The reported reason for worsening conditions was increasing population pressures

along most of the coast.

The level of confidence in the assessment of the future outlook was low for 24 (nearly two-thirds) of

Pacific estuaries.

Data Gaps and Research Needs

The estuaries of the Pacific Coast are predominantly

understudied, particularly in Oregon and in some

areas of California. Thus, there is a need for baseline

monitoring of basic water-quality parameters in

these areas. In addition, research is needed to determine the fate of nutrients and their eventual impacts

on primary production and human uses of the resources. If water quality is to be managed properly

in the presently pristine systems, as well as in those

with insufficient data, a much better understanding

is needed of the linkages between nutrient inputs,

productivity and eutrophic symptoms.

A bloom of nuisance algae mars an estuary in the state of Washington. Photo courtesy of Puget Sound Water Quality Action Team.
40

Conclusions
41

Conclusions

The National Estuarine Eutrophication Assessment provides a picture of nutrient-enrichment related water quality conditions in the nation’s estuaries. These conclusions are based on data and information about water quality conditions, the

influence of natural and human-related factors, estuarine use impairments, and management recommendations compiled

for 138 estuaries (>90% of U.S. estuarine surface area) and also for the Mississippi River Plume. The results, which were

reviewed and synthesized by experts at a National Assessment Workshop, provide a comprehensive assessment of the

location, magnitude, and consequences of eutrophication in the nation’s estuaries.

Eutrophic Conditions in Estuaries

The overall expression of eutrophic conditions was high

in 44 (one-third) of the 138 estuaries studied, and moderate in an additional 40 estuaries. Thus, 84 estuaries—

60% of those studied—exhibited moderate to high

eutrophic conditions. Although the greatest number

of estuaries with pronounced problems were found

in the Gulf of Mexico and Middle Atlantic regions,

estuaries showing high levels of eutrophic conditions

were found along all of the nation’s coasts. Furthermore, it is important to note that the estuaries assessed

as having a high expression of eutrophic conditions

were those that have been the best studied. In the

many estuaries that are understudied or for which

very little is known, eutrophication may be more serious than the limited data reveal.

Symptoms and Related Use Impairments

About 40 percent (58) of the nation’s estuaries show high

levels of chlorophyll a, epiphytes, or macroalgae, signs

of the initial stages of eutrophication. In terms of their

impacts on estuaries, the most important symptoms indicative of eutrophication are low dissolved oxygen, the

loss of submerged aquatic vegetation, and blooms of

nuisance and toxic algae. More than half (82) of U.S.

estuaries, representing 67% of the estuarine surface area

studied, had moderate to high expressions of at least

one of these symptoms. This finding is of concern because these symptoms can have serious consequences,

including negative impacts on commercial fisheries, the

loss of recreational opportunities, and potential risks to

human health.

The experts identified more than half of the studied

estuaries as having use impairments related to

eutrophic conditions. The implications are serious and

affect not only the natural resources but also the

economy and human health. The resource uses most

frequently reported as being impaired were commercial fishing and shellfish harvesting. Recreational fishing, swimming, and boating, all of which contribute

to tourism in coastal areas, were also reported as impaired to some degree. The reported risks to human

health include the consumption of tainted shellfish,

as well as direct skin contact or the inhalation/ingestion of water during an active bloom of toxic algae.

High expressions of eutrophic conditions are exhibited in 44 estuaries, representing 40% of the

total estuarine surface area studied.

High conditions occur in estuaries along all

coasts, but are most prevalent along the Gulf

of Mexico and Middle Atlantic coasts.

Key Findings

82 estuaries, representing 67% of the surface

area studied, exhibit moderate to high expressions of either depleted dissolved oxygen, loss

of submerged aquatic vegetation, or nuisance/

toxic algal blooms.

69 estuaries were identified by workshop participants as having human use impairments related to eutrophication.

Compared to other impaired uses, commercial/

recreational fishing and shellfisheries were

identified as impaired for human use in the

greatest number of estuaries (43 and 46, respectively).

Key Findings

Conclusions
42

Conclusions

Influencing Factors on Eutrophication

Most estuaries that showed high levels of eutrophic conditions were moderately to highly influenced by human-related nutrient inputs (e.g., wastewater treatment,

agriculture, urban runoff, atmospheric deposition). Of

the 44 estuaries with high expressions of eutrophic conditions, 36 were assessed as being highly influenced by

human activities despite relatively moderate nutrient

inputs. Most of these estuaries were in the Gulf of

Mexico, the Middle Atlantic, and the Pacific regions.

Most of the 44 estuaries (86 %) also had moderate to

high susceptibility to retaining nutrient inputs; that is,

their unique physical characteristics made them vulnerable to developing the symptoms of eutrophication.

It follows that susceptibility is an important factor in

the expression of high eutrophic conditions, especially

when nutrient inputs are not extremely high. Furthermore, of the 38 estuaries with a low expression of

eutrophic conditions, 10 had high susceptibility, suggesting that they are at risk of future degradation, if

human-related nutrient inputs increase.

Implications for Management

The assessment of eutrophic conditions and influencing

factors provides a basis for identifying priority estuaries

needing remedial and preventive management action. The

level of human influence is a factor in determining to what

degree management actions can reduce or reverse

eutrophic problems; if the major influence is natural, then

it is likely that little can be done, except to plan appropriately. If the major influence is human-related, then impacts

may be reduced with appropriate management actions.

Therefore, in the 36 estuaries with high expressions of

eutrophic conditions and high human influence, conditions

can be moderated or reversed with appropriate management action. The success of these efforts depends in part

on susceptibility; low susceptibility enhances the effectiveness of nutrient reductions by flushing or diluting nutrients at the same time that inputs are reduced, while highly

susceptible estuaries may require greater effort due to their

natural tendency to retain nutrients.

Of the non-impacted estuaries, those with moderate to high

susceptibility are in need of preventive action because they

are most at risk of developing problems if nutrient inputs

increase. In contrast, the estuaries that have low overall

expressions of eutrophic conditions, low human influence

and low susceptibility may not benefit as much from management action. In general, these estuaries are less susceptible to developing problems to begin with. Some estuaries, such as many of those in Maine, exhibit naturally high

levels of eutrophic symptoms, mostly due to toxic algal

blooms. In these estuaries, however, reductions in nutrient

inputs are not likely to greatly affect conditions. While these

estuaries should not be ignored, nutrient control is not urgent at the present time.

A high level of human influence is associated

with 36 of the 44 estuaries (82%) with a high

expression of eutrophic conditions.

Only six of the 44 estuaries (14%) with highlevel eutrophic conditions have corresponding

high-level nitrogen inputs.

Of the 44 estuaries with high-level eutrophic

conditions, more than half (25) exhibit a high

susceptibility to retaining nutrients.

Key Findings

The 23 estuaries with high expressions of

eutrophic conditions and high susceptibility

will likely require greater management effort

and longer response time for results than those

estuaries with low susceptibility. These estuaries represent approximately 10% of national

estuarine surface area in the study.

There are 10 estuaries, representing 3% of the

national estuarine surface area studied, that

have low eutrophic conditions and high susceptibility. Of the non-impacted estuaries, these

are the most at risk of developing problems.

Key Findings
43

Conclusions

Future Outlook and Management Concerns

Experts at the National Assessment Workshop estimated that the severity and extent of eutrophic conditions would worsen in 86 (nearly two-thirds) of

the studied estuaries and in the Mississippi River

Plume during the next 20 years, during which time

the coastal population is expected to increase by

more than 10 percent. The estuaries most at risk are

those that presently do not show symptoms but are

highly susceptible to retaining nutrients and are located in watersheds in which significant population

growth is projected. Most of these estuaries are located in the South Atlantic and Gulf of Mexico regions. Only eight (6%) of 138 estuaries are expected

to improve unless more is done to resolve this pervasive environmental problem.

There is reason for optimism that eutrophication effects

can be moderated or reversed. The predictions of future

outlook may not have taken into account the effectiveness of management efforts presently being pursued but

not yet completely effective, and those presently planned

but not yet implemented. There have been measurable

improvements in estuaries (e.g., Tampa Bay, Sarasota Bay,

and parts of Chesapeake Bay) for which there are comprehensive watershed nutrient reduction strategies in

place, and from which lessons can be learned. The improvements are mainly a result of point source treatment.

However, there is a continued need to further reduce

nutrient inputs in order to counteract the effects of expected population growth and other factors that promote

the development of eutrophic problems. If further management actions are implemented and better coordinated

now, it is possible that the future outlook will be more

positive.

Nutrient inputs from agriculture, wastewater treatment, urban runoff, and atmospheric deposition

were identified as the most important management

targets. Agricultural nutrient sources were mentioned as especially important for management consideration in the Pacific, Gulf of Mexico, and South

Atlantic regions. Wastewater treatment plants were

identified most often in the North Atlantic. In the

Middle Atlantic, agriculture and atmospheric deposition were equally recommended as sources requiring management. The participants also emphasized

the importance of managing nutrient inputs from a

watershed perspective. Management plans must also

take into account human and natural factors, including

sources of nutrients as well as watershed alterations that

affect the delivery of nutrients (e.g., the loss of wetlands)

to maximize the benefit from nutrient reductions.

Eutrophic conditions could worsen in 86 estuaries by the year 2020 if projected development

patterns are realized.

Of the 86 estuaries projected to worsen, 43 exhibit only low to moderate eutrophic conditions.

Of particular concern, especially if human-related nutrient inputs increase, are the 10 estuaries with low eutrophic conditions and high

susceptibility.

All of the typical point and nonpoint pollution sources were identified at the National Assessment Workshop as important to target in

order to manage nutrient problems. There are,

however, some regional differences in important nutrient sources (e.g., combined sewer

overflows in the North Atlantic).

Key Findings
44

Conclusions

Data Gaps and Research Needs

Among the most important data gaps highlighted

by this assessment is the lack of information about

the levels of eutrophic symptoms and trends. Of 138

estuaries, 39 (nearly 30%) were rated as “low confidence” for the assessment of eutrophic conditions.

The factors leading to low confidence include one

or more unknown symptoms, poor spatial or temporal resolution of data, and the inclusion of information based on expert judgment and observation

rather than data. An additional 17 estuaries (12%)

have insufficient data to make any assessment at all.

In general, better characterization is needed for existing levels and trends of symptoms and of nutrient inputs, including estimators of inputs such as

land use and population. This information is necessary to assess overall eutrophic conditions, to establish baseline conditions, and to track the condition

of an estuary. It would be especially useful in evaluating the success of management actions. This information is also needed to determine causal relationships so that appropriate management strategies

can be implemented. Among the primary sources

of human-related nutrient inputs, more data are particularly needed for atmospheric and groundwater contributions, which are not well known due to

the difficulties in obtaining accurate measurements.

Additionally, better estimates of population growth

are needed for future projections of water quality.

Research is also needed to improve scientists’ understanding of the mechanisms involved in, and influences on, the eutrophication process, such as the

triggering of toxic algal blooms. Better characterization of basic circulation patterns would increase understanding of how nutrients are processed once

they reach an estuary, and thus, the potential outcome in terms of eutrophication. Factors that affect

nutrient delivery, such as weather patterns, land use,

and dramatic changes in seasonal population density due to tourism, should also be studied. Other

research should be directed toward understanding

the linkages between the expression of eutrophic

symptoms and the resulting impacts to biological

resources and risks to human health.

Despite all of the monitoring and research done

to date, information and knowledge still is inadequate in 48 estuaries (low confidence or inadequate data for assessment). These estuaries

represent approximately 25% of the estuarine

surface area studied.

All participants in the National Assessment

process agreed that research is needed to clarify

the linkages between eutrophication and impacts on estuarine resources, including fisheries, recreation and tourism, and risks to human

health.

The National Assessment process confirms that

much remains to be done to adequately characterize nutrient pressure on estuaries. Better

quantification is needed of total nutrient inputs, inputs by source, and estimators of nutrient pressure (e.g., population and land use). Atmospheric and groundwater inputs are least

well quantified.

Better characterization of physical factors is

needed, including basic circulation patterns, effects of weather patterns, climate change,

changing land use, and resultant effects on nutrient delivery, circulation, and eutrophic conditions.

Other research needs include defining the relationship between nutrient inputs and toxic

blooms, better characterization of assimilative

capacity, and characterization of the effects of

seasonal population changes.

Key Findings
45

Toward A National Strategy

At present, there is not a comprehensive national strategy to address the potentially worsening problems of estuarine eutrophication. However, the results from this Assessment can help provide an improved basis for setting national priorities for management, monitoring, and research. In combination with successes in individual estuaries, such as those recently reported for

Tampa and Sarasota Bays, these results can provide the information necessary to help guide the development of a comprehensive

national strategy to reduce problems where they are presently observed and protect the nation’s coastal waters from further

degradation.

Why is a National Strategy Needed?

This National Assessment confirms that estuarine

eutrophication is indeed a problem of national significance. It indicates that human-related nutrient

sources, both nearby and far removed, are substantial contributors to eutrophic conditions within estuaries. Furthermore, many estuarine watersheds

cross the boundaries of states, requiring regional,

subregional and interagency cooperation. Similarly,

there are many important needs with regard to research, monitoring, and assessment that also call for a cogent national strategy. In many instances, for

example, eutrophication research has

been conducted on a parochial and

piecemeal basis, which can impede the

rapid advance of scientific understanding of the linkages between

eutrophication and marine resources.

A national strategy is needed, especially one that effectively integrates

watershed-specific approaches to assessment and management into a

comprehensive approach.

How Can These Results Be

Used?

National Assessment results can be

used to help better focus national attention on existing and emerging priority areas for action; i.e., management,

monitoring, and research. The framework shown (Figure 30) can be used

to organize assessment results for this

purpose. In particular, estuaries that

are in serious condition should be priorities for management actions; those

in less serious condition, but at risk of

deterioration, should be closely monitored, and efforts should be made to

identify preventive measures. In addition, estuaries for which there is insufficient information should be targeted for basic monitoring and assessment activities.

The framework incorporates the overall eutrophic

condition of an estuary, its natural susceptibility to

retain nutrients, and the level of nutrient inputs, to

help set priorities for appropriate actions that will

allow the most effective results given environmental concerns and resource limitations. This process

can be considered environmental triage—necessary

due to limited resources—which allows the sorting

of estuaries into groups based on their need for, or

Toward a National Strategy

Figure 30. A framework for developing a national strategy

Estuaries with No or 

Low symptoms

Impacted Estuaries - 

“Naturally Occurring”

Impacted Estuaries -

Human Influenced 

Eutrophication 

Moderate to 

High 

Susceptibility

Low 

Susceptibility

•Nutrient Management 

 (reduce inputs)

•Research 

•Nutrient Management 

 (reduce inputs)

•Remediation (restore sea grasses, 

 oyster beds, wetlands, etc.)

•Research 

•Research (linkages between 

 nutrients and symptoms - e.g. 

 harmful algal bloom research)

None to Low 

Secondary Symptoms

None to Low Primary 

Symptoms

Low Overall Eutrophic 

Conditions

Moderate to High 

 Human Influence

 Nutrient Inputs

ENVIRONMENTAL TRIAGE MANAGEMENT RESPONSE

Moderate to High 

Eutrophic Conditions

Low Human Influence

Unknown or 

Low Confidence 

in Susceptibility

•Susceptibility Research and Analysis

Considerations for Priority Setting 

and Actions Needed

Assessment of Eutrophic 

Condition and Human Influence

Assessment of 

Susceptibility

Unknown/Low 

Assessment 

Confidence

 •Assessment of Eutrophic Condition

•Assessment of Nutrient Inputs

• Preventive Measures 

• Early Warning Monitoring

Moderate to 

High 

Susceptibility

Low 

Susceptibility

•Susceptibility Research and Analysis

•Preventive Measures

•Early Warning Monitoring

“Naturally 

Occurring”

Symptoms 

Unknown or 

Low Confidence 

in Susceptibility e.g. Toxic Blooms

Eutrophic Conditions

Nutrient Inputs

priority need for basic assessments 

requires more intensive effort

requires less intensive effort
46

Toward A National Strategy

Nutrient enrichment and associated

eutrophic conditions have been identified as a critical problem in the nation’s

estuaries for over three decades.

As the 20th century comes to a close, a

cogent and comprehensive national

strategy still remains elusive.

likely benefit from, treatment. By such sorting, a

framework is created that allows for logical and effective decisions on how to allocate limited management, monitoring, and research resources among a

large number of estuaries. Note that this is not the

only way that the National Assessment results might

be used; this framework is offered as guidance for

how the information might be used in planning a

national strategy.

Management

The national assessment indicates that eutrophic

symptoms are driven, in large measure, by humanrelated nutrient sources. However, the response of a

system to reductions in nutrient input is dependent

upon its natural susceptibility in combination with

the level of nutrient input it receives. Thus, in the

management of nutrient sources, no one nutrient

control strategy is likely to achieve the desired results in all estuaries across the nation.

The proposed assessment framework provides a

basis for distinguishing between the remediation of

systems that are already impacted, and preventive

measures in systems that are at risk due to potential

increases in nutrient loading. Both are necessary for

improving and protecting the health of the nation’s

estuaries, and the assessment results should be used

to guide appropriate management and remediation

plans. For instance, different plans should be implemented for those estuaries that, although in serious

condition, might be improved with additional management effort; those in less serious condition but at

risk of worsening that should be closely monitored

and managed; and those for which a basic assessment is needed because there is presently insufficient information to evaluate conditions. The selection of priority estuaries for management action

within these groups should be based on the level of

eutrophic conditions, the influence of human activities, and the natural sensitivity to nutrients, to assure the most effective results within the constraints

of limited resources. The national assessment provides a heretofore unavailable capability to target

the nation’s investments to control eutrophication.

Monitoring and Research

Some of the most useful information that has been

developed while conducting this assessment is a

comprehensive understanding of what is actually

known about the phenomenon called “eutrophication,” how well it is known, and whether it is understood well or not at all. When taken together, the

assessment data base and framework provide a

“working model” for designing and evaluating the

efficiency and effectiveness of alternative national

strategies for monitoring and research.

For example, there is a need to strike the right balance between monitoring designed primarily to describe spatial patterns or extent (e.g., EPA’s Environmental Monitoring and Assessment Program) and

fixed, continuous monitoring that emphasizes temporal resolution (both short- and long-term) and the

tracking of nutrients and eutrophic symptoms. The

data base and framework can also be used to determine how monitoring programs can be integrated

across scales (local, regional, national) and across media (water, air, land).

The assessment results also reconfirm the need for

monitoring programs that are capable of documenting ephemeral or real-time changes in symptoms,

such as day-to-night fluctuations in dissolved oxygen, as well as over long time frames. Observational

systems, such as the Global Ocean Observing System that is presently being developed, need to be

promoted and sustained.

Within the framework of research, the detail that the

assessment provides on the perspective of estuaries

as mixing zones between rivers and oceans is invaluable for determining where to direct many research

efforts. For example, the results of this national assessment should provide useful input to the National

Research Council’s ongoing study of the causes and

management of coastal eutrophication, which will

help to further identify key science needs.
47

Toward A National Strategy

Data sources referenced during the National Assessment Workshop

Data Sources

Physical and Hydrologic Characteristics Nutrient Indicators

NOAA, 1985. National Estuarine Inventory, Volume 1: Physical and 

Hydrologic Characteristics. National Ocean Service, Silver Spring, MD.

Note: This information is now included as part of NOAA’s Coastal 

Assessment and Data Synthesis System (CA&DS) and can be accessed 

at http://cads.nos.noaa.gov.

NOAA. 1993. Tide Tables 1993, High and Low Water Predictions. National 

Ocean Service, Silver Spring, MD

USGS, not dated. Water Resources Data. Gaged Streamflow Data. Water 

Resources Division, Reston, VA.

Smith, et al., 1997. Spatially Referenced Regressions on Watershed 

Attributes (SPARROW). In: Regional Interpretation of Water Quality 

Monitoring Data. Water Resources Research, Vol 33, No. 12, pp. 2781-98

USDA, 1987 and 1992. Census of Agriculture. CD-ROMs for 1987 

and 1992. 

USGS, 1990. County Level Estimates of Nitrogen and Phosporus 

Fertilizer Use in the US 1945-85. In: Alexander and Smith, 1990. 

USGS Open File Report 90-130.

US EPA, 1990 and J. Fletcher 1992 (written comm., U West VA). 

County Level Estimates of Nitrogen Fertilizer Sales in the 

Conterminous US 1986-91. In: Alexander and Smith, 1990. USGS 

Open File Report 90-130.

USGS, various dates. Land Use and Land Cover (LUDA).

US Bureau of the Census, undated. 1970 and 1990 population 

estimates. Population Estimates Program, Population Division. 

Washington, DC.

NPA Data Services, Inc, 1988. Key Indicators of County Growth 

1970-2010. Washington, DC.

Estuary Boundaries and 

Water Surface Areas

Estuarine Salinity Zones

Estuary Average Depth

Estuary Volume

Watershed Boundaries (EDAs & 

FDAs) and Land Surface Areas

Vertical Stratification

Freshwater Inflow

Dilution Potential

Flushing Potential

Susceptibility: Estuarine Export 

Potential (EXP)

Tide Range

NOAA. 1998. Coastal Assessment and Data Synthesis System. 

National Ocean Service, Silver Spring, MD.

Nitrogen Loads (kg/yr)

and Yields (kg/sq. mi/yr)

Nitrogen Trends from Livestock 

(1978-92)

Nitrogen Trends from Fertilizer 

Use (1970-91)

Cropland Area Trends (sq.miles) 

(1978-92)

Land Use (sq. miles)

Population (1970 and 1990)

Population (2010)

Soil Conservation Service, April, 1992, the Agricultural Waste 

Management Field Handbook, Chapter 4.

USDA, 1987 and 1992. Census of Agriculture. CD-ROMs for 1987 

and 1992. 

Eutrophication

NOAA. 1998. NOAA’s estuarine eutrophication survey, vol. 5: Pacific 

Coast region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 75 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, vol. 4: Gulf of 

Mexico region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 77 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, volume 3: 

North Atlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 46 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, vol. 2: MidAtlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 51 pp.

NOAA. 1996. NOAA’s estuarine eutrophication survey, vol. 1: South 

Atlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 50 pp.

Eutrophic Conditions and 

Trends
48
Appendix A: Methods

49

National Survey: Data Collection and

Synthesis

NOAA conducted three workshops in 1991-92 with

local and regional estuarine scientists and coastal resource managers. Two workshops held in January

1991 consisted of presentations by invited speakers

and discussions of the measures and effects associated with nutrient problems. The purpose was to

facilitate the exchange of ideas on how to best characterize eutrophication in U.S. estuaries and to consider suggestions for the design of NOAA's proposed data collection survey. A third workshop, held

in April 1992, focused specifically on developing

recommendations for conducting a nationwide survey.

Given the limited resources available for this project,

it was not practical to try to gather and consolidate

the existing data records. Even if it were possible to

do this, it would be very difficult to merge these data

into a comprehensible whole due to incompatible

data types, formats, time periods, and methods. Alternatively, NOAA elected to systematically acquire

a consistent and detailed set of qualitative data from

the existing expert knowledge base (i.e., coastal and

estuarine scientists) through a series of surveys, interviews, and regional workshops. Based on the

workshops and additional meetings with experts,

NOAA identified information requirements for a set

of parameters which could be used to characterize

estuarine nutrient enrichment and eutrophication

This appendix describes the methodology used in the National Eutrophication Survey and the National Estuarine Eutrophication Assessment. The survey process was used to establish a database of current (ca. 1995) eutrophication conditions and

trends (ca. 1970-1995) for all coastal regions of the coterminous United States. The National Assessment is an aggregation

and interpretation of the Eutrophication Survey data plus additional assessments of human influence, future outlook,

impaired uses, potential management concerns, and data gaps and research needs.

conditions. To be included in the survey, a parameter had to be (1) essential for accurate characterization of nutrient enrichment related phenomena; (2)

generally available for most estuaries; (3) comparable among estuaries; and (4) based upon existing

data and/or knowledge (i.e., no new monitoring or

analysis required).

The next step was to establish response ranges for

each parameter to ensure discrete gradients among

responses. For example, the survey asked whether

total dissolved nitrogen in the water column is high,

medium, or low based upon specific thresholds

(High ≥ 1 mg/l, Medium ≥ 0.1 < 1 mg/l, low > 0

<0.1 mg/l, or unknown). The ranges were determined from reviewing nationwide data and from

discussions with eutrophication experts. The thresholds used to classify ranges are designed to distinguish conditions among estuaries on a national basis.

Data Collection Framework. For each parameter,

information was collected for existing conditions and

recent trends (circa 1970-1995). Existing conditions

describe maximum parameter values observed over

a typical annual cycle (e.g., normal freshwater inflow, average temperatures, etc.). For instance, for

nutrients, information was collected characterizing

peak concentrations observed during the annual

cycle such as those associated with spring runoff

and/or turnover. For chlorophyll a, information was

collected on peak concentrations that are typically

reached during a bloom period.

Additional information describing the timing and duration of

existing conditions was collected.

Survey

Design

testing, 

review

National 

Survey

 next steps 

workshop

Site 

Visits

Assessment 

Workshops

Regional 

Reports

Eutrophication Survey Process

Appendix A: Methods
Appendix A: Methods

50

Eutrophication Survey Parameters

CHLOROPHYLL A

TURBIDITY

SUSPENDED SOLIDS

NUISANCE ALGAE

TOXIC ALGAE

MACROALGAE

EPIPHYTES

NITROGEN

ANOXIA (0 mg/l)

HYPOXIA (>0mg/l ≤ 2mg/l)

BIOL. STRESS (>2mg/l ≤ 5mg/l)

PRIMARY PRODUCTIVITY

PLANKTONIC COMMUNITY

SUBMERGED AQUATIC VEG.

INTERTIDAL WETLANDS

EXISTING CONDITIONS TRENDS

Hypereutrophic (>60 μg chl-a/l) High (>20, ≤60 μg chl-a/l)

Medium (>5, ≤20 μg chl-a/l) Low (>0, ≤5 μg chl-a/l)

• Surface concentrations:

• Limiting factors to algal biomass (N, P, Si, light, other)

• Spatial coverage1, Months of occurrence, Frequency of occurrence2

• Secchi disk depths:

High (<1m), Medium (1≥m, ≤3m), Low (>3m), Blackwater area

• Concentrations3,4

• Concentrations:

Problem (significant impact upon biological resources)

No Problem (no significant impact)

• Months of occurrence, Frequency of occurrence2

• Occurrence

• Dominant species

• Event duration (Hours, Days, Weeks, Seasonal, Other)

• Abundance

• Maximum dissolved surface concentration:

 High (≥1 mg/l), Medium (≥0.1, <1 mg/l), Low (≥0, < 0.1 mg/l)

High (≥0.1 mg/l), Medium (≥0.01, <0.1 mg/l), 

Low (≥0, < 0.01 mg/l)

• Dissolved oxygen condition

(Surface, Bottom, Throughout water column)

• Stratification (degree of influence): (High, Medium, Low, Not a factor)

• Water column depth:

• Dominant primary producer:

Pelagic, Benthic, Other

• Temporal shift

• Dominant taxonomic group (number of cells):

Diatoms, Flagellates, Blue-green algae, Diverse mixture, Other

Crustaceans, Molluscs, Annelids, Diverse mixture, Other 

• Temporal shift

BENTHIC COMMUNITY

• Dominant taxonomic group (number of organisms): • Temporal shift

PARAMETERS

PHOSPHORUS

• Maximum dissolved surface concentration:

• Spatial coverage1, Months of occurrence

• Limiting factors

• Contributing factors5

• Concentrations3,4

• Contributing factors5

• Event duration3,4

• Frequency of occurrence3,4

• Contributing factors5

• Abundance3,4

• Contributing factors5

• Concentrations3,4

• Contributing factors5

• Concentrations3,4

• Contributing factors5

• Min. avg. monthly bottom

 dissolved oxygen conc.3,4

• Frequency of occurrence3,4

• Event duration3,4

• Spatial coverage3,4

• Contributing factors5

• Contributing factors5

• Contributing factors5

• Contributing factors5

• Spatial coverage3,4

• Contributing factors5

NOTES

(1) SPATIAL COVERAGE (% of salinity zone): High (>50, ≤100%), Medium (>25, ≤50% ), Low (>10, ≤25%), Very Low (>0, ≤10% ), 

 No SAV / Wetlands in system 

(2) FREQUENCY OF OCCURRENCE: Episodic (conditions occur randomly), Periodic (conditions occur annually or predictably), 

 Persistent (conditions occur continually throughout the year)

(3) DIRECTION OF CHANGE: Increase, Decrease, No trend

(4) MAGNITUDE OF CHANGE: High (>50%, ≤100%), Medium (>25%, ≤50%), Low (>0%, ≤25%) 

(5) POINT SOURCE(S), NONPOINT SOURCE(S), OTHER

• Spatial coverage1, Months of occurrence, Frequency of occurrence2

• Months of occurrence, Frequency of occurrence2

• Months of occurrence, Frequency of occurrence2

• Spatial coverage1, Months of occurrence

• Spatial coverage1, Months of occurrence, Frequency of occurrence2

• Spatial coverage1

(maximum values observed over a typical annual cycle) (1970 - 1995)

(no trends information collected)

Problem (significant impact upon biological resources)

No Problem (no significant impact)

Observed

No Occurrence

ALGAL CONDITIONS NUTRIENTS DISSOLVED OXYGEN ECOSYSTEM / COMMUNITY RESPONSE

Problem (significant impact upon biological resources)

No Problem (no significant impact)
Appendix A: Methods

51

NOAA's National Estuarine Inventory (NEI) was

used as a spatial framework to collect and organize

information. Each parameter was characterized for

three salinity zones as defined in the NEI (tidal fresh

0-0.5 ppt, mixing 0.5-25 ppt, and seawater >25 ppt),

providing a consistent basis for comparisons among

the estuarine systems.

Data Collection. Survey forms designed to collect

information on 16 parameters related to nutrient enrichment and eutrophication were mailed in 1993 to

over 400 experts who had agreed to participate in

the survey. The response rate was approximately 25

percent with at least one response for 112 of the 129

estuaries being surveyed. The survey methods and

Regional Workshop Assessment Review Process

Part 3

• –––––––

• –––––––

• –––––––

• –––––––

• –––––––

Part 2

• ––––––– • –––––––

• ––––––– • –––––––

• –––––––

Estuary 1 Salinity Zone 

Considerations

Part 1

• ––––––– • –––––––

• ––––––– • –––––––

• –––––––

 question 1

 question 2

 question 3

Not Answerable

Notes

Consensus

Next Part

Next 

Estuary

Part 1

Spatial Framework Example

initial results were evaluated in May 1994 by a panel

of NOAA, state, and academic experts. The panel

recommended that NOAA proceed with a regional

approach for completing data collection, including

site visits with selected experts to fill data gaps, regional assessment workshops to finalize and reach

consensus on the responses to each question, and

regional reports on the results. Estuaries were targeted for site visits based upon the completeness

of the data received from the original mailed survey forms. The new information collected from

site visits was incorporated into the project data

base and summary materials were then prepared

for regional workshops.

Workshop participants included local and regional experts (at least one per estuary representing the group of people with the most extensive

knowledge and insight about an estuary). In general, these persons had either filled out a survey

form and/or participated in a site visit. Preparations included sending all regional data to participants prior to workshops. Participants were

also encouraged to bring to the workshops relevant data and reports. During the workshops,

NOAA staff facilitated a careful discussion and

review of the survey data and salinity maps for

each estuary and recorded the results accordingly.

Participants were also asked to rank the reliability as either highly certain or speculative inference, reflecting the robustness of the data the response is based on. This is especially important

given that responses are based upon a range of

information sources from statistically tested monitoring data to general observations. Following the

workshops, results were summarized for review by

workshop participants. The information was then

compiled into regional reports that were also reviewed by participants prior to publication.
Appendix A: Methods

52

Analysis of Data Completeness and

Reliability (DCR)

The estuarine eutrophication survey is a compilation of information for 16 water quality parameters

that are related to nutrient enrichment. These parameters, in various combinations and at specific

levels, are reflections of eutrophic conditions. For

each of these parameters, information on characteristics of timing, duration, spatial coverage, and

frequency of occurrence was also collected as appropriate. The robustness of this data set is affected

by two factors - missing data and data that are

judged to be based on speculative inference. Data

gaps were created when respondents could not supply information —either information was not available or was of insufficient quality or quantity to give

a reasonable answer. Responses were deemed speculative when, in the respondents judgment, they were

based on either very limited data or general observations. The extent of data gaps and speculative responses is important because formulations developed

to assess the rating of eutrophication status on a national basis use combinations of the parameters and

parameter characteristics. The power of these formulations to accurately discriminate among systems is

reduced if they contain significant gaps or a high degree of speculative inferences.

Data completeness and reliability was defined as the

percent of the total area of the estuary for which there

was a known value that was considered highly certain for each parameter. DCR was calculated as follows:

2. A rating based on the DCR score was assigned to each parameter and to the entire system as follows:

High = 75 - 100 %

Medium = 50 - 74%

Low = 0 - 49%

 The entire estuarine system DCR value was then computed as the mean of the parameter DCRs.

Chlorophyll a Concentration * Spatial Coverage * Frequency * Reliability

Epiphytes Concentration * Frequency * Reliability

Macroalgae Concentration * Frequency * Reliability

Dissolved Oxygen** Concentration * Spatial Coverage * Frequency * Reliability

SAV Direction of change * Magnitude *Reliability

Nuisance algae Concentration * Frequency * Duration * Reliability

Toxic algae Concentration * Frequency * Duration * Reliability

** (mean of Anoxia, Hypoxia, and Biological Stress

The DCR scores were used by participants at the National Assessment Workshop to help assign confidence

ratings to the overall eutrophic conditions assessment of estuaries (see Appendix B).

Surf. Area 

(sq. mi.)

Concentration ReliabilitySpatial 

Coverage Reliability

Frequency ReliabilitySum of 

DCR Area

Survey 

response 3 Low Highly 

certain Not eval. Not eval. Not eval. Not eval. --

DCR value 3 1 1 1 1 1 1 3

Survey 

response 28.8 Medium Highly 

certain High Spec-ulative Periodic Highly certain --

DCR value 28.8 1 1 1 0 1 1 0

Survey 

response 18.1 Unknown Unknown Unknown Unknown Unknown Unknown --

DCR value 18.1 0 0 0 0 0 0 0

System Total 49.9 -- -- -- -- -- -- 3

Tidal Fresh

Mixing

Seawater

Salinity Zone

Note that the speculative reliability rating for the spatial coverage call in the mixing zone and the

unknown call for chlorophyll a concentration in the seawater zone result in the areas of these zones

being zeroed out in the calculation. Note also that spatial coverage and frequency are not evaluated

when concentrations are low. Thus, the DCR value for this parameter for this estuary would be:

(3 (tidal fresh) + 0 (mixing) + 0 (seawater))/System Total = 3/49.9 = 0 .061

Thus the DCR in the example above would be rated Low (6.1%).

The following is an example of the DCR calculation of chlorophyll a for an estuary.

1. A DCR calculation was made for each estuary by using the following combinations of parameter characteristics:
Appendix A: Methods

53

The National Assessment

In all, the eutrophication survey produced a data array containing over 40,000 data values (120-1,200/

estuary). While providing the best possible resolution of the problem, the array also represented a challenge to interpret the data. NOAA worked with a

“core group” of 15 scientists and managers who participated in the original data survey to develop and

apply methods that best integrate the survey data

for each estuary. It seemed reasonable that eutrophication symptoms and their time/space characteristics could be combined in a way that provided a

single categorical value to represent the status of

eutrophic conditions for each estuary. The assessment also included human influence, impaired uses

of estuaries, nutrient management targets, future

outlook, and data gaps and research needs.

The Eutrophication Model. The core group participated in two work sessions to develop and test

several analytical and numerical methods. Ultimately, a single model was developed that made

maximum use of the survey data and best described

the sequence and severity of eutrophication conditions. The model used six symptoms that were most

Nitrogen and 

Phosphorus

Extreme Chl-a

Concentrations

Problematic 

Epiphytic Growth 

SAV Spatial 

Coverage

Diatoms to 

Flagellates

Benthic 

Dominance to 

Pelagic 

Dominance

Anoxia

Hypoxia

Biological Stress

Nuisance Bloom 

Problems

Toxic Bloom 

Problems

Primary 

Symptoms

Secondary 

Symptoms

Extreme Chl-a

Concentrations

Problematic 

Macroalgal

Growth

Problematic 

Macroalgal

Growth

Loss of Submerged 

Aquatic Vegetation

SAV Spatial 

Coverage Trends

Decreased Light 

Availability

Algal Dominance 

Changes Harmful Algae 

Increased 

Organic Matter

Decomposition

Low Dissolved 

Oxygen 

External 

Nutrient Inputs

Eutrophication model used for National Assessment

directly related to nutrient inputs. Three primary

symptoms, algal abundance (using chlorophyll a as

an indicator), epiphyte abundance, and macroalgae

represent the first possible stage of water quality degradation associated with eutrophication. Although

nitrogen and phosphorus concentrations in the water column are directly related to nutrient inputs,

elevated concentrations do not necessarily indicate

that eutrophication symptoms are present. Likewise,

low water column concentrations do not necessarily translate to no problems present. Thus, these were

not included as primary symptoms in the model.

In many estuaries, the primary symptoms lead to

secondary symptoms, such as submerged aquatic

vegetation loss, nuisance and toxic algal blooms, and

low dissolved oxygen (anoxia and hypoxia). In some

cases, secondary conditions can exist in the estuary

without originating from the primary symptoms.

This occurs, for instance, in many North Atlantic estuaries where toxic algal blooms are transported into

these systems from the coastal ocean.

Determining the Overall Eutrophic Condition

A numerical scoring system was developed to integrate information from all six primary and

secondary symptoms to determine the

overall status of eutrophication symptoms

in each estuary. This scoring system was

implemented in three phases.

First, a single index value was computed

from all primary symptoms. An average of

the three symptoms was then made to provide an overall score for the primary symptoms.

Next, a single index value was computed

from all secondary symptoms. The highest

secondary score of the three symptoms was

assigned to the estuary rather than taking

an average. This was done because an estuary exhibiting high impacts from only one

of the conditions may be just as impacted

as an estuary with all three symptoms.

Finally, the range of numeric scores assigned

to primary and secondary symptoms were

divided into categories of high, moderate,

and low. Primary and secondary scores were

then compared in a matrix so that overall

categories could be assigned to the estuaries. A detailed description of these three

phases follows.
Appendix A: Methods

54

Chlorophyll a Level of Expression Determination

Concentration

Hypereutrophic 

or

High

Spatial Coverage

High

Moderate

Low

Frequency

Periodic

Periodic

Periodic

High Episodic

Moderate Episodic

Spatial coverage and frequency of occurrence are used to determine the level of expression for each 

salinity zone and are then aggregated up to the estuary level (See Estuary Aggregation Rules ).

Expression

High

High

Moderate

Moderate

High

THEN

Concentration

Medium

1

1

0.5

1

0.5

Very Low Periodic Moderate 0.5

Spatial Coverage

High

Moderate

Low/Very Low

Frequency

High Episodic

Mod/Low/Very Low Episodic

High

Moderate

Low

Low

Moderate

1

0.5

0.25

0.5

0.25

Unknown Flag A 0.5

Unknown Flag A 0.5

Concentration

Low Low 0.25

Value

Expression

Expression

Any Frequency

Any Frequency

Low/Very Low Low 0.25 Episodic

Unknown Flag A 0.5

Unknown Flag A 0.5

Any Spatial

Coverage

Spatial Coverage Frequency

Any 

Frequency

Concentration Spatial Coverage Frequency

Unknown Unknown Unknown

Not included in calculation 

at zone level

IF AND AND

Periodic

Periodic

Periodic

Any Spatial

Coverage

Any Spatial

Coverage

Phase 1: Primary Symptoms Method Description. This method assesses the level of expression of chlorophyll

a concentrations, epiphyte abundance problems, and macroalgal abundance problems. The method uses only

the survey information pertinent to each particular symptom to determine the level of expression. For chlorophyll a, concentration, spatial coverage and frequency of occurrence are used; for epiphytes and macroalgae, the

frequency of occurrence of problem conditions was used.

Classification Criteria. The following is a set of decision rules which were applied to the eutrophication survey

data to determine the level of expression of the primary symptoms.
Appendix A: Methods

55

Flags A through C are used to identify components for which not enough data was available. In these cases, assumptions

were made based on conservative estimates that unknown spatial coverage is at least 10 percent of a zone, and that

unknown frequency is at least episodic.

Phase 1: Primary Symptoms Method, continued.

Epiphyte Problem Level of Expression Determination

The frequency of problematic epiphytic growth is used to 

determine level of expression at the salinity zone level and is 

then aggregated up to the estuary level (See Estuary 

Aggregation Rules).

Epiphyte 

Problems

Observed

High

Moderate

Frequency

Episodic

Unknown Flag B

Expression Value

1

0.5

0.5

Unknown Unknown Not included in 

calculation at zone level

Periodic

IF THEN AND

Macroalgae Problem Level of Expression Determination

The frequency of problematic macroalgal growth is used to 

determine level of expression at the salinity zone level and is 

then aggregated up to the estuary level (See Estuary 

Aggregation Rules).

Macroalgae 

Problems

Observed

High

Moderate

Frequency

Episodic

Unknown Flag C

Expression Value

1

0.5

0.5

Periodic

Unknown Unknown Not included in 

calculation at zone level

IF AND THEN

Estuary Aggregation Rules

For each symptom (chlorophyll a, epiphytes, and macroalgae), an area weighted expression 

value for each zone is determined. First the surface area of the salinity zone is multiplied by 

the symptom expression value for the zone and then divided by the surface area of the entire 

estuary to obtain an area weighted value for the zone. The area weighted values are then 

summed to obtain the estuary level of expression value for the symptom.

Estuary Expression Value

≥ 0 to ≤ 0.3

>0.3 to ≤ 0.6

>0.6 to ≤ 1

Level of Expression Category Assigned

Low

Moderate

High

The level of expression of the primary symptoms for the estuary is determined by 

calculating the average of the three estuary level of expression values (chlorophyll a, 

epiphytes, and macroalgae).

The estuary is then assigned a category for Primary Symptoms as follows: 

n= total number of zones in estuary

Az= surface area of a single zone

At= total surface area of estuary

Symbols:

A t

A z

∑

i = 1

n

Expression 

Value = symptom level of expression 

 value for estuary

1.

2.

3.
Appendix A: Methods

56

Low Dissolved Oxygen Level of Expression Determination

Spatial coverage and frequency of occurrence are used to determine level of expression at the zone level and are then 

aggregated up to the estuary level (See Estuary Aggregation Rules ).

Anoxia

Observed

Spatial Coverage

High

Moderate

Low

Frequency

Periodic

Periodic

Periodic

High Episodic

Moderate/Low/Very Low Episodic

Expression

High

High

Moderate

Low

Moderate

Hypoxia

Observed

1

1

0.5

0.5

0.25

Very Low Periodic Low 0.25

Spatial Coverage

High

Mod

Low/Very Low

Frequency

Periodic

Periodic

Periodic

High Episodic

Moderate/Low/Very Low Episodic

High

Moderate

Low

Low

Moderate

1

0.5

0.25

0.5

0.25

Unknown Flag A 0.25

Unknown Flag B 0.25

Biological Stress

Observed

Spatial Coverage

High

Moderate/Low /Very Low

Frequency

Periodic

Periodic

Episodic

Moderate

Low

Low

0.5

0.25

0.25

Unknown Flag C 0.25

Any Spatial Coverage

Value

Expression Value

Expression Value

Any frequency

Any frequency

Any frequency

IF AND AND THEN

Phase 2: Secondary Symptoms Method Description. This method uses the same approach as used for the

primary symptoms in order to assess the level of expression of depleted dissolved oxygen (anoxia, hypoxia,

biological stress), submerged aquatic vegetation decline, and nuisance/toxic blooms. The method uses the information pertinent to each particular symptom to determine the level of expression. For depleted dissolved

oxygen, spatial coverage and frequency of occurrence were used; for submerged aquatic vegetation decline, the

magnitude of change of the decline in spatial extent was used; for nuisance/toxic blooms, the duration of bloom

events and frequency of occurrence was used.

Classification Criteria. The following is a set of decision rules which were applied to the eutrophication survey

data to determine the level of expression for low dissolved oxygen conditions, submerged aquatic vegetation

declines, and nuisance/toxic blooms.
Appendix A: Methods

57

Phase 2: Secondary Symptoms Method Description, continued.

Flags A through F are used to identify impacts for which not enough data was available for the components. In these

cases, assumptions were made based on conservative estimates that unknown spatial coverage is at least 10 percent of

the zone, unknown duration is at least days, and unknown frequency is at least episodic.

Nuisance and Toxic Blooms Level of Expression Determination

Submerged Aquatic Vegetation (SAV) Loss Level of Expression Determination

The magnitude of loss of the decline is used to determine the level of expression at the 

zone level and is then aggregated up to the estuary level (See Estuary Aggregation Rules ).

SAV Loss

Observed

High

Moderate

Low

Magnitude of Loss

High

Moderate

Low

Unknown Flag D

Expression Value

1

0.5

0.25

0.25

IF THEN AND

The duration of bloom events and frequency of occurrence is used to determine impact severity at the salinity zone level, 

and are then aggregated up to the estuary level (See Estuary Aggregation Rules).

S = seasonal, M = months, V = variable, W = weeks, D = days, WS = weeks to seasonal, WM = weeks to months, 

DW = days to weeks

Nuisance Blooms Frequency

Problem

Duration Expression

DW, V, W

D

Moderate

Low

Episodic

Unknown

M, WM, WS, S, PR Periodic High 1

Value

Periodic 0.5

Periodic 0.25

DW, V, W

D

M, WM, WS, S, PR

Episodic

Episodic

Moderate

Low

0.5

0.25

Low 0.25

Flag E 0.25

Toxic Blooms Frequency

Problem

Duration Expression

DW, W, V

D

Moderate

Low

Episodic

Unknown

M, WM, WS, S, PR Periodic High 1

Value

Periodic 0.5

Periodic 0.25

DW, W, V

D

M, WM, WS, S, PR

Episodic

Episodic

Moderate

Low

0.5

0.25

Low 0.25

Flag F 0.25

Any Frequency

Any frequency

IF AND AND THEN
Appendix A: Methods

58

Phase 3: Determination of the Overall

Level of Expression of Eutrophic Conditions. The primary and secondary symptoms were next compared in a matrix to determine an overall ranking of eutrophic conditions for the estuary. The overall assessments were reviewed by experts at the National Assessment Workshop. In some cases

changes were made to these assessments

based on the experts knowledge of the estuary. For instance, if an estuary was near

the borderline of moderate and moderately

high, expert judgement may have been used

to move the category up or down based on

comparison with the condition of other

similar estuaries in the area.

In this report low and moderate low are

grouped together as low; moderate high and

high are grouped together as high.

Phase 2: Secondary Symptoms Method Description, Continued.

Interpretation and Review. At the National

Assessment Workshop, experts reviewed

each primary and secondary symptom assessment for all 138 estuaries in the survey.

In some cases changes were made to these

assessments based on the experts knowledge of the estuary. For instance, borderline

estuaries with values around 0.3 and 0.6

were sometimes moved up or down a category level based on the experts knowledge

of recent conditions not reflected by the

original survey data.

OVERALL LEVEL OF EXPRESSION OF EUTROPHIC CONDITIONS

LOW

MODERATE

MODERATE LOW MODERATE HIGH

Moderate secondary 

symptoms indicate 

substantial eutrophic 

conditions, but low 

primary indicates other 

factors may be involved 

in causing the conditions.

Level of expression of 

eutrophic conditions is 

minimal.

High secondary symptoms 

indicate serious problems, 

but low primary indicates 

other factors may also be 

involved in causing the 

conditions.

Primary symptoms 

begining to indicate 

possible problems but 

still very few secondary 

symptoms expressed.

Primary symptoms high but 

problems with more serious 

secondarysymptoms still not 

being expressed.

Level of expression of 

eutrophic condtions is 

substantial.

Substantial levels of 

eutrophic conditions 

occurring with secondary 

symptoms indicating 

serious problems.

Primary symptoms high and 

substantial secondary 

symptoms becoming more 

expressed, indicating 

potentially serious 

problems.

High primary and 

secondary symptom 

levels indicate serious 

eutrophication problems.

MODERATE LOW HIGH

MODERATE MODERATE HIGH HIGH

Low Secondary 

Symptoms

Moderate Secondary 

Symptoms

High Secondary 

Symptoms

0 0.3 0.6 1

Low Primary Symptoms Moderate Primary Symptoms High Primary Symptoms

0.3

0.6

1

n= total number of zones in estuary

Az= surface area of a single zone

At= total surface area of estuary

Symbols:

A t

A z

∑

i = 1

n

Expression 

Value

symptom level

of expression

value for estuary

= 

For each symptom (anoxia, hypoxia, biological stress, submerged aquatic

vegetation loss, nuisance blooms, toxic blooms), an area weighted expression value for each zone is determined. First the surface area of the salinity

zone is multiplied by the symptom expression value for the zone and then

divided by the surface area of the entire estuary to obtain an area weighted

value for the zone. The area weighted values are then summed to obtain

the estuary level of expression value for the symptom.

The level of expression of the secondary symptoms for the estuary is determined by choosing the highest of the three estuary level symptom expression values (depleted dissolved oxygen, submerged aquatic vegetation loss, and nuisance/toxic blooms). For dissolved oxygen the highest

value is chosen from the anoxia, hypoxia, or biological stress values. For

blooms the highest value is chosen from the nuisance or toxic bloom values.

The estuary is then assigned a category for Secondary Symptoms as follows:

1.

2.

3.

Expression Value

≥ 0 to ≤ 0.3 

>0.3 to ≤ 0.6

>0.6 to ≤ 1

Level of Expression Category Assigned

Low

Moderate

High

Estuary Aggregation Rules
Appendix A: Methods

59

IF: Vertical Stratification THEN: Dilution Volume IF: Dilution Value Dilution Potential

Vertically Homogenous 

•all year

•throughout estuary

Minor Vertical Stratification

•navigation channels

•upper estuary

Vertically Stratified

•most of year

•most of estuary

1 / VOLestuary

1 / VOLestuary

1 / VOLfwf

10-13

10-12

HIGH

10-10

10-09

10-11 MODERATE

LOW

Number 

of Estuaries

30

63

45

Type

A

B

C

(fwf = freshwater fraction)

Determining Overall Human Influence

This analysis was performed as an attempt to determine

the extent to which human activities have contributed to

the observed eutrophic symptoms and conditions. The

underlying assumption is that any particular level of

nutrient input will have varying effects in different estuaries due to varying levels of susceptibility to the nutrient inputs. Therefore, separate analyses of both susceptibility and nutrient inputs were made and then the results

of each were combined to determine the overall level of

human influence.

Susceptibility: Determining the Estuarine Export Potential (EXP)

Estuarine susceptibility to nutrients is dependent in large

part on the amount of time that nutrients entering a system stay in the system before exiting the system. The estuarine export potential is a method, developed as part

of NOAA’s Coastal Assessment and Data Synthesis system, to estimate relative determinations of this amount

of time by defining the relative capacity of estuaries to

dilute and flush dissolved nutrient loads. The analysis

uses physical and hydrologic data to define separately 1)

a dilution rating and 2) a flushing rating. In both cases,

the higher the rating, the greater the capacity to dilute or

flush nutrient loads (conversely, lower ratings suggest a

greater tendency to retain nutrient loads).

2. Decision Rules for FLUSHING Potential. This analysis assumes that a greater capacity to flush nutrient

loads exists for estuaries that have large tide and freshwater influences.

Type Tide Range (ft) Freshwater Inflow/Estuary Volume Flushing Potential Number 

of Estuaries

1 macro (>6) large or moderate HIGH 12

2 21

3 meso (>2.5) large HIGH 15

4 meso (>2.5) MODERATE 16

5 meso (>2.5) small LOW 26

6 micro (<2.5) large 4 HIGH

7 micro (<2.5) 13

8 micro (<2.5) LOW 31

and

and

and

and

and

and

and

and

(1000 to 10-02)

macro (>6) small (10-03, 10-04) MODERATE

(1000, 10-01)

moderate (10-02)

(10-03, 10-04)

(1000, 10-01)

moderate (10-02) MODERATE

small (10-03, 10-04)

1. Decision Rules for DILUTION Potential. This analysis assumes that a larger portion of the water column is potentially available to dilute nutrient loads in a vertically homogenous estuary than in a vertically stratified system. The

assumption is that for stratified systems, nutrients are most often retained in the upper portion (freshwater fraction) of

the water column. In contrast, downward transport (more complete mixing) is likely in vertically homogenous systems. Type B estuaries are generally vertically homogenous, although stratification is observed (confined) in narrow

navigation channels or the extreme upper reaches of an estuary. In this case, nutrients are assumed to be diluted

throughout the entire water column.
Appendix A: Methods

60

Combining Dilution Potential and Flushing Potential. By combining dilution and flushing components, an EXP is determined. Estuaries in the upper left portion of the matrix generally have a high

EXP that suggests an ability to dilute and flush nutrient loads. Estuaries in the lower right portion suggest estuaries that lack the ability to dilute or flush

nutrients, making them more susceptible to nutrient pollution.

Nutrient Inputs. In order to develop an understanding of the amount of nutrient inputs being delivered to the estuarine systems from human activities, nationally comparable data sets had to be developed. Estimates of nitrogen and phosphorus

loads from point, nonpoint, and atmospheric sources

were developed for each estuarine watershed. The

USGS' SPARROW (spatially referenced regressions

of contaminant transport on watershed attributes)

model was used as the primary indicator of nitrogen pressure. In addition, a host of other data sets

were used as surrogate nutrient pressure indicators

to help substantiate load estimates. These included

EPA's county level estimates of fertilizer sales, USGS'

county level estimates of fertilizer use, USGS' Land

Use/Land Cover, U.S. Census Bureau Population

Census, and U.S. Department of Agriculture Census of Agriculture (see Data Sources Table).

A brief description of the SPARROW model is

provided here, as this was the principal data set

used to evaluate the extent of nitrogen pressure

with respect to the observed eutrophic symptoms. Estimates of total nitrogen loads are provided for five major nutrient source types: point

sources, fertilizer, livestock, atmospheric deposition, and nonpoint/nonagricultural. Data are

available for all USGS 8-digit hydrologic catalog units and are based on measurements from

a national network of stream gaging stations

(NASQAN) that operated during 1970-1988. For

the purposes of the national workshop, NOAA

aggregated data for the 8-digit units to the watershed scale, though this may have overestimated actual loads to some estuaries. The modeled estimates provide a snapshot of conditions

during the early-1980s and do not offer time

series data.

Determination of the Overall Level of Human Influence. The susceptibility to retain nutrients and

the level of nitrogen inputs were compared in a matrix to determine an overall ranking of the overall

level of expression of human influence on eutrophic

conditions in the estuary.

Low Nutrient Input Moderate Nutrient Input High Nutrient Input

High Susceptibility Moderate Susceptibility Low Susceptibility

Symptoms observed in the 

estuary are likely 

predominantly naturally 

related or caused by human 

factors other than nutrient 

additions.

Symptoms observed in the 

estuary are predominantly 

naturally related or caused 

by factors other than nutrient 

additions.

Symptoms observed in the 

estuary may be naturally 

related or the high level of 

nutrient additions may cause 

problems despite low 

susceptibility.

Symptoms observed in the 

estuary are minimally to 

moderately related to 

nutrient inputs.

Symptoms observed in the 

estuary are moderately 

related to nutrient inputs.

Symptoms observed in the 

estuary are moderately to 

highly related to nutrient 

additions.

Even low nutrient additions 

may result in problem 

symptoms in these 

estuaries.

Symptoms observed in the 

estuary are moderately to 

highly related to nutrient 

additions.

Symptoms observed in the 

estuary are probably closely 

related to nutrient additions.

MODERATE

MODERATE

MODERATE HIGH

MODERATE HIGH

HIGH

MODERATE LOW

LOW LOW MODERATE LOW

OVERALL LEVEL OF HUMAN INFLUENCE

High Moderate Low

High Moderate Low

DILUTION Potential

FLUSHING Potential

HIGH EXP. Estuary has capacity to dilute 

and flush nutrients

MODERATE EXP. Estuary has capacity 

to either dilute or flush nutrients

LOW EXP. Estuary does not have capacity to 

dilute or flush nutrients

ESTUARINE EXPORT POTENTIAL AND SUSCEPTIBILITY

Low 

Susceptibility

Low 

Susceptibility

Low 

Susceptibility

Moderate 

Susceptibility

Moderate 

Susceptibility

Moderate 

Susceptibility

High 

Susceptibility

High 

Susceptibility

High 

Susceptibility

Experts at the National Assessment Workshop reviewed and, when appropriate, modified the susceptibility or nutrient pressure assessments. Modifications were made based on higher quality data

available for some estuaries and expert knowledge

and judgement.
Appendix A: Methods

61

Determining Future Outlook

This analysis was performed as an attempt to determine the likelihood of whether conditions in

an estuary will worsen, improve, or stay the same

over the next twenty years. In the analysis, nutrient input changes are predicted to determine

which direction conditions will move. The estuarine susceptibility to nutrients is then used to determine the magnitude. Population projections

are used as a primary indicator of the level of

future nutrient input changes. However, population projections are subject to unpredictable

changes. Therefore, experts at the National Assessment Workshop were asked to make modifications to the determinations of future nutrient

changes, based on their knowledge of planned

or likely changes that will take place in the estuarine basins that will affect the level of nutrients entering the system.

Identifying Impaired Uses and Potential

Management Concerns

Experts at the National Assessment Workshop identified impaired uses which they judged to be related

to the expression of eutrophic conditions in the water body. These impaired uses included recreational

and commercial fishing, fish consumption, shellfish,

swimming, boating, aesthetics, tourism, SAV and

habitat loss, and loss of assimilative capacity. Although this information is not supported by a comprehensive data set, it does provide a rough picture

of the extent of problems stemming from eutrophic

conditions. The experts also identified the point and

nonpoint sources which they judged as most important to target for managing nutrients. These sources

included wastewater treatment, combined sewer

overflow, on-site waste disposal such as septic systems, industrial discharge, large animal operations,

urban runoff, agriculture, forestry practices, rangeland use, atmospheric inputs, and aquaculture. Also

evaluated were potential effectiveness of nutrient reductions and watershed focus areas. Although these

assessments were not based on a national data set,

the expert evaluations are useful for gaining a first

order understanding at the national level of what

types and level of actions will be required to address

eutrophication.

Identifying Data Gaps and Research Needs

Experts at the National Assessment Workshop identified data gaps and research needs for improving

the assessment of the severity, human influence,

impacts, and appropriate response to eutrophication

in estuaries. The experts used their experience and

knowledge, in combination with data completeness

and reliability analysis of the eutrophication survey

results, to produce these findings.

Future Nutrient 

Pressures Decrease

No Change in Future 

Nutrient Pressures 

Future Nutrient 

Pressures Increase

High Susceptibility Moderate Susceptibility Low Susceptibility

Nutrient related 

symptoms observed in 

the estuary will most 

likely remain 

unchanged.

Nutrient related 

symptoms observed in 

the estuary are likely 

to worsen only 

minimally.

Nutrient related 

symptoms observed in 

the estuary are likely to 

improve.

Nutrient related 

symptoms observed in 

the estuary will most 

likely remain 

unchanged.

Nutrient related 

symptoms observed in 

the estuary are likely 

to substantially 

worsen.

Nutrient related 

symptoms observed in 

the estuary are likely to 

improve somewhat.

Nutrient related 

symptoms observed in 

the estuary will most 

likely remain 

unchanged.

Nutrient related 

symptoms observed in 

the estuary are likely 

to substantially worsen.

FUTURE OUTLOOK FOR EUTROPHIC CONDITIONS

Nutrient related 

symptoms observed in 

the estuary are likely to 

improve substantially.

IMPROVE HIGH NO CHANGE WORSEN LOW

IMPROVE LOW

IMPROVE LOW

NO CHANGE

NO CHANGE

WORSEN HIGH

WORSEN HIGH 
Appendix A: Methods

62

Data sources referenced during the National Assessment Workshop. Physical and Hydrologic Characteristics Nutrient Indicators

NOAA, 1985. National Estuarine Inventory, Volume 1: Physical and 

Hydrologic Characteristics. National Ocean Service, Silver Spring, MD.

Note: This information is now included as part of NOAA’s Coastal 

Assessment and Data Synthesis System (CA&DS) and can be accessed 

at http://cads.nos.noaa.gov.

NOAA. 1993. Tide Tables 1993, High and Low Water Predictions. National 

Ocean Service, Silver Spring, MD

USGS, not dated. Water Resources Data. Gaged Streamflow Data. Water 

Resources Division, Reston, VA.

Smith, et al., 1997. Spatially Referenced Regressions on Watershed 

Attributes (SPARROW). In: Regional Interpretation of Water Quality 

Monitoring Data. Water Resources Research, Vol 33, No. 12, pp. 2781-98

USDA, 1987 and 1992. Census of Agriculture. CD-ROMs for 1987 

and 1992. 

USGS, 1990. County Level Estimates of Nitrogen and Phosporus 

Fertilizer Use in the US 1945-85. In: Alexander and Smith, 1990. 

USGS Open File Report 90-130.

US EPA, 1990 and J. Fletcher 1992 (written comm., U West VA). 

County Level Estimates of Nitrogen Fertilizer Sales in the 

Conterminous US 1986-91. In: Alexander and Smith, 1990. USGS 

Open File Report 90-130.

USGS, various dates. Land Use and Land Cover (LUDA).

US Bureau of the Census, undated. 1970 and 1990 population 

estimates. Population Estimates Program, Population Division. 

Washington, DC.

NPA Data Services, Inc, 1988. Key Indicators of County Growth 

1970-2010. Washington, DC.

Estuary Boundaries and 

Water Surface Areas

Estuarine Salinity Zones

Estuary Average Depth

Estuary Volume

Watershed Boundaries (EDAs & 

FDAs) and Land Surface Areas

Vertical Stratification

Freshwater Inflow

Dilution Potential

Flushing Potential

Susceptibility: Estuarine Export 

Potential (EXP)

Tide Range

NOAA. 1998. Coastal Assessment and Data Synthesis System. 

National Ocean Service, Silver Spring, MD.

Nitrogen Loads (kg/yr)

and Yields (kg/sq. mi/yr)

Nitrogen Trends from Livestock 

(1978-92)

Nitrogen Trends from Fertilizer 

Use (1970-91)

Cropland Area Trends (sq.miles) 

(1978-92)

Land Use (sq. miles)

Population (1970 and 1990)

Population (2010)

Soil Conservation Service, April, 1992, the Agricultural Waste 

Management Field Handbook, Chapter 4.

USDA, 1987 and 1992. Census of Agriculture. CD-ROMs for 1987 

and 1992. 

Eutrophication

NOAA. 1998. NOAA’s estuarine eutrophication survey, vol. 5: Pacific 

Coast region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 75 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, vol. 4: Gulf of 

Mexico region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 77 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, volume 3: 

North Atlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 46 pp.

NOAA. 1997. NOAA’s estuarine eutrophication survey, vol. 2: MidAtlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 51 pp.

NOAA. 1996. NOAA’s estuarine eutrophication survey, vol. 1: South 

Atlantic region. Silver Spring, MD: Office of Ocean Resources 

Conservation and Assessment. 50 pp.

Eutrophic Conditions and 

Trends
Appendix B: Table of Results

63

This appendix contains results of the National Estuarine Eutrophication Assessment, including some information that is not provided elsewhere in the

report, i.e., overall primary and secondary assessments, nutrient reduction effectiveness, and the type of watershed focus. The data is also presented as

determined at the Assessment Workshop, i.e., “moderate low” was not combined with “low,” nor was “moderate high” combined with “high.”

Impaired uses are indicated by their assessment basis: highly certain, moderately certain, or reasonable inference. Primary Secondary Influencing Future Impaired Uses Potential Management Concerns

Eutrophic Condition

Wastewater Treatment

Combined Sewer Overflow

On-site (septics, etc.)

Industry

Animal Operations

Urban Runoff

Agriculture

Forestry Activities

Rangeland Use

Atmosphere

Aquaculture

Other

Would Nutrient Reductions

Improve Conditions?

Watershed Focus

Rec./Comm. Fishing

Fish Consumption

Shellfish

Swimming

Boating

Aesthetics

Tourism

SAV/Habitat Loss

Assimilative Capacity

Expected Change (2020)

Confidence

Overall Human Influence

Confidence

Susceptibility

Nitrogen Yield

Low Dissolved Oxygen

SAV Loss

Nuisance/Toxic Blooms

Overall Secondary Level

a Chlorophyll 

Epiphyte Abundance

Macroalgal Abundance

Overall Primary Level

N - none observed; L - low; ML - moderate low; M - moderate; MH - moderate high; H - high; U - unknown; IH - improve high; IL - improve low; NC - no change; WL - worsen low; WH - worsen high RI - reasonable inference;

MC - moderately certain; HC - highly certain; WC - water column; ENTR - entire watershed; EDA - estuarine drainage area; FDA - fluvial drainage area

North Atlantic

St. Croix River/Cobscook Bay MH MH L L H L L N H H L H L M WH M HC NO WC √

Englishman Bay MH MH M N H H N U M M L MH L L NC MH HC NO WC √

Narraguagus Bay MH MH M N N M N U H H L MH L L NC MH HC NO WC √

Blue Hill Bay ML ML M N N M N N L L L H L L WL M HC NO U

Penobscot Bay L MH L N N L N U N L ML MH L M NC MH NO EDA √ √

Muscongus Bay ML L M N N M L U L L L L L M NC M HC NO EDA √

Damariscotta River M H M N N M N N M M M H M M WL M MC NO WC √

Sheepscot Bay MH MH M N M M L U H H ML H M M NC MH HC NO EDA

Kennebec/Androscoggin Rivers ML H M N N M L N N L L H L M NC MH NO U √

Casco Bay MH H M L M L L M H H ML MH L L IL MH HC U ENTR √√ √

Saco Bay M MH L U N L L U H H L MH L L NC M RI NO ENTR √ √

Great Bay M MH M L M M L N L M ML MH M L WH MH MC U FDA √ √

Hampton Harbor Estuary ML L M N N M L N N L L ML L L WL M MC NO U √

Merrimack River U U U U U L U M U M L ML L L NC ML U U

Plum Island Sound ML MH M N N M L N N L MH M M H WH L U FDA √

Massachusetts Bay M MH M N H H N L M M M MH L H WL MH HC YES EDA √√ √

Boston Harbor MH H M H M H M L N L MH H M H IL MH YES EDA √√ √

Cape Cod Bay M MH M N L M L L L M ML H M L NC H NO ENTR √ √

Middle Atlantic

Buzzards Bay ML H M L L L L L N L ML H M L NC H U U

Narragansett Bay ML H M N L L L L M M MH H M H NC H U U

Gardiners Bay MH H M N N M L H M H ML M M L NC M HC HC HC HC HC HC YES ENTR √ √√

Long Island Sound MH H H L H H M L M M MH H H M NC H HC HC HC YES ENTR √ √√

Connecticut River ML L M U U M L U N L M L M M NC L U U

Great South Bay MH H H N N H L M M M M H H L NC H HC HC HC HC YES ENTR √ √

Hudson River/Raritan Bay M H H L L M M N M M MH H M H NC H HC HC MC YES ENTR √√ √

Barnegat Bay H H H N H H L U H H MH H H M WL H MC YES ENTR √

New Jersey Inland Bays ML L M N L M L U L L MH L H M WH L U U

Delaware Bay ML H M N N M L N N L MH H M H NC H U ENTR √ √

Delaware Inland Bays H H M U H H L N H H MH MH H L NC M HC MC MC HC RI YES ENTR √√ √

Maryland Inland Bays M M H M N M L N M M M H H L WL L RI RI RI RI YES EDA √ √

Chincoteague Bay ML L M U U M L N N L M L H L WL L U U

Chesapeake Bay H H H H N H H H N H H H H M WL H RI HC HC RI YES ENTR √ √√

Patuxent River H H H U N H M H H H MH H H M WL H RI HC RI MC YES ENTR √ √√

Potomac River H H H U L M H M M H MH H H M WL H RI HC MC YES ENTR √ √√

Rappahannock River M H H N N M M N N M H H H M WL H RI HC MC YES ENTR √ √√

York River MH H M N N M M M N M MH H H L WH H RI HC RI MC YES ENTR √ √√

James River ML H H N N M L N N L MH H M M WL H RI RI YES ENTR √ √√

Chester River M H M U N M L L N L MH H H M WL H RI MC YES ENTR √ √

Choptank River M H M H M H L H M H MH H H M WL H RI MC YES ENTR √ √

Tangier/Pocomoke Sounds MH H H H H H L H L M H H H H WH H HC HC HC RI U ENTR √

Appendix B: Table of Results
Appendix B: Table of Results

64Primary

Symptoms

Secondary

Symptoms

Influencing

Factors

Future

Outlook Impaired Uses Potential Management Concerns

Eutrophic Condition

Confidence

Wastewater Treatment

Combined Sewer Overflow

On-site (septics, etc.)

Industry

Animal Operations

Urban Runoff

Agriculture

Forestry Activities

Rangeland Use

Atmosphere

Aquaculture

Other

Would Nutrient Reductions

Improve Conditions?

Watershed Focus

Rec./Comm. Fishing

Fish Consumption

Shellfish

Swimming

Boating

Aesthetics

Tourism

SAV/Habitat Loss

Assimilative Capacity

Expected Change (2020)

Confidence

Overall Human Influence

Confidence

Susceptibility

Nitrogen Yield

Low Dissolved Oxygen

SAV Loss

Nuisance/Toxic Blooms

Overall Secondary Level a Chlorophyll 

Epiphyte Abundance

Macroalgal Abundance

Overall Primary Level

N - none observed; L - low; ML - moderate low; M - moderate; MH - moderate high; H - high; U - unknown; IH - improve high; IL - improve low; NC - no change; WL - worsen low; WH - worsen high

RI - reasonable inference; MC - moderately certain; HC - highly certain; WC - water column; ENTR - entire watershed; EDA - estuarine drainage area; FDA - fluvial drainage area

South Atlantic

Albemarle Sound U U L N N L L L L L M L M M WL M NO EDA √√ √

Pamlico Sound U U M N N M L L M H M L M M NC M MC YES ENTR √ √

Pamlico/Pungo Rivers MH H H N N H M M M M MH H H M NC M HC MC RI YES ENTR √√√

Neuse River H H H N N H H L H H H H H H NC M HC MC MC HC MC MC YES ENTR √ √√

Bogue Sound ML M M U N M N U L L L L H L IL M U EDA √√ √

New River MH M H N N H L U H H MH M L M IL M MC RI RI MC YES ENTR √ √√

Cape Fear River M M H N N H L U N L M L H M NC M MC RI U ENTR √√√

Winyah Bay ML L M N N M M N N M M M M M NC M RI NO EDA √ √

N. Santee/S. Santee Rivers ML L U N N L M U N M ML M M L NC M NO U

Charleston Harbor M H M N M M M N N M M M M M WH M HC HC YES ENTR √ √√

Stono/North Edisto Rivers ML M U N N L M N N M M M H L NC M NO EDA √ √

St. Helena Sound U U L U U L M U U M L M L L IL M NO EDA √ √

Broad River ML M L U U L M U N M ML M M L WH M NO ENTR √√ √

Savannah River M M M N N M M N N L L M L M WL M HC HC NO ENTR √√√

Ossabaw Sound ML L M N N M L U N L L ML L M WL M NO ENTR √√√

St. Catherines/Sapelo Sounds ML L M N N M L N N L ML L M L WH M NO EDA √ √

Altamaha River ML M M N N M L N N L L M M M WL M NO ENTR √√√

St. Andrew/St. Simons Sounds ML L M N N M L N N L ML L M L WH M NO EDA √ √

St. Marys R./Cumberland Snd. M L M N N M M N N L ML L M L WH M RI NO EDA √√√ √

St. Johns River MH L H M N H M L L M M L H L WH L U U

Indian River M L M M M M M M L M M L H L WH L U U

Biscayne Bay L L L N N L L N N L U U H U WH L U U

Gulf of Mexico

Florida Bay H MH M H H H H M M H MH L M U IL M HC HC RI RI HC HC YES ENTR √√ √

South Ten Thousand Islands MH L M N N M H L N H MH L H U WL M U U

North Ten Thousand Islands M M M N N M M U N M M L H U WL L U U

Rookery Bay ML M L N N L L N N L ML L H U NC L U U

Charlotte Harbor MH M H M N M H L M H MH M H L WL M U ENTR √ √√

Caloosahatchee River MH M H N N H L L N L MH M M M WL M RI RI MC YES FDA √

Sarasota Bay MH H M H L M M N H M MH H M H WL M RI YES ENTR √√ √

Tampa Bay MH H H N N H L N M M MH H M M NC M MC MC YES ENTR √ √√

Suwannee River M M M N M L L N L L ML M M L WL M NO FDA √ √√

Apalachee Bay ML L M N N M L N M M ML L M L WL L U U

Apalachicola Bay M H M N N M M N M M MH H M M WL M U U

St. Andrew Bay M M M L L L M U L M M L M L WL L YES EDA

Choctawhatchee Bay MH M M H L M M M H H MH M M M WL L RI RI YES EDA

Pensacola Bay M M M U U M M M N M MH M M M WL L RI YES EDA √ √

Perdido Bay M M M N H H M N L M MH M H M WL L RI MC YES EDA √ √

Mobile Bay M M M N N M M L M M M M M M NC M HC U ENTR √ √

East Mississippi Sound M L M N N M M M L M M L M M NC L MC U U

West Mississippi Sound ML M M L N L L M L M M M M M NC L U U

H
Appendix B: Table of Results

65

Primary

Symptoms

Secondary

Symptoms

Influencing

Factors

Future

Outlook Impaired Uses Potential Management Concerns

Eutrophic Condition

Confidence

Wastewater Treatment

Combined Sewer Overflow

On-site (septics, etc.)

Industry

Animal Operations

Urban Runoff

Agriculture

Forestry Activities

Rangeland Use

Atmosphere

Aquaculture

Other

Would Nutrient Reductions

Improve Conditions?

Watershed Focus

Rec./Comm. Fishing

Fish Consumption

Shellfish

Swimming

Boating

Aesthetics

Tourism

SAV/Habitat Loss

Assimilative Capacity

Expected Change (2020)

Confidence

Overall Human Influence

Confidence

Susceptibility

Nitrogen Yield

Low Dissolved Oxygen

SAV Loss

Nuisance/Toxic Blooms

Overall Secondary Level a Chlorophyll 

Epiphyte Abundance

Macroalgal Abundance

Overall Primary Level

N - none observed; L - low; ML - moderate low; M - moderate; MH - moderate high; H - high; U - unknown; IH - improve high; IL - improve low; NC - no change; WL - worsen low; WH - worsen high

RI - reasonable inference; MC - moderately certain; HC - highly certain; WC - water column; ENTR - entire watershed; EDA - estuarine drainage area; FDA - fluvial drainage area

Gulf of Mexico (continued)

Lake Borgne U U U U U L N U M M M L M M NC L U U

Lake Pontchartrain H M M H H H L H M H H M M M WH M YES U

Breton/Chandeleur Sounds ML L U U N L L L N L ML L M L IL L U U

Mississippi River ML M M N N M L N N L M H L M NC M U U

Barataria Bay M M HNNHMNL M M M M M NC M U U

Terrebonne/Timbalier Bays M M H N N H L U L L M M H L WL M U U

Atchafalaya/Vermilion Bays M M H N N H L L N L M M L L NC M U U

Mississippi River Plume H H H N N H H N H H H H U U WH M U U

Mermentau Estuary L L U N N L N N N L L L M M IL L U U

Calcasieu Lake H M H N N H M M H H MH M M M WL M YES U

Sabine Lake M M M N N M L N L L MH M M M NC M RI YES EDA √ √ √√ √

Galveston Bay MH H M N N M L H L H MH M M M WL M HC HC HC HC HC YES EDA √ √ √√ √

Brazos River M M M N N L M N L M M M M L NC M RI MC RI RI YES EDA √√√

Matagorda Bay M M M N N M L N L L MH M H L WL M MC RI YES EDA √ √√ √ √√√

San Antonio Bay MH M M H H H L L L L MH M M L WL M RI RI YES ENTR √ √ √ √√

Aransas Bay MMMMHM L L L L M M H M NC L RI RI RI RI YES ENTR √ √√ √

Corpus Christi Bay H M H H H H L N H H MH M H L WH H MC RI RI YES EDA √ √√ √

Upper Laguna Madre H H H N N H M M H H H M H M WH M MC MC MC YES EDA √ √ √√

Baffin Bay H L H N N H L N H H H L H M WH L MC MC MC MC YES ENTR √ √√√ √√

Lower Laguna Madre H H H N N H L M H H H M H L WH H MC MC MC MC YES ENTR √ √√√ √√

Pacific

Tijuana Estuary H H H N H H M N L M H H H H WH H RI RI HC HC YES EDA √

San Diego Bay M L U N H H L U L L MH L H M WH L U U

Mission Bay ML L L N N L N N N L MH L H M WL L U U

Newport Bay H MH H N H H H M L M H H H H WH H HC HC HC HC YES EDA √ √

San Pedro Bay L L L N N L N N L L H L H H WL U U

Alamitos Bay ML L UNNLMNLMUUHUU U U

AnaheimBay M M U N H H L U L L H M H H WL M MC MC YES ENTR √ √

Santa Monica Bay U U U U L L U N L L MH L M H NC U U

Morro Bay M L U U H H L H H H MH L H M NC U U

Monterey Bay ML M M N N L L N M M ML ML L L WL M U ENTR √ √

Elkhorn Slough MH L M H H H M N M M MH L H M NC U U √ √

San Francisco Bay H H H N N H L H N H H H M M WL M NO EDA √ √

Cent. SF./San Pablo/Suisun Bays M H M N N M L M H M L H L M NC MH NO ENTR √ √√

Drakes Estero U U U U U L U U N L MH L L M WH U U

Tomales Bay MH L U N N L N N H H MH L H M WH U U

Eel River L L L N N L N N N L M L M M WL U U

Humboldt Bay L L L N N L N N N L MH L H M NC U U

Klamath River L L L N N L N N N L ML L M L NC U U

Rogue River U U U U U L N L U L M L M M WL L U U

Coquille River U U L U U L N N U L ML L M L WL L YES EDA √
Appendix B: Table of Results

66Primary

Symptoms

Secondary

Symptoms

Influencing

Factors

Future

Outlook Impaired Uses Potential Management Concerns

Eutrophic Condition

Confidence

Wastewater Treatment

Combined Sewer Overflow

On-site (septics, etc.)

Industry

Animal Operations

Urban Runoff

Agriculture

Forestry Activities

Rangeland Use

Atmosphere

Aquaculture

Other

Would Nutrient Reductions

Improve Conditions?

Watershed Focus

Rec./Comm. Fishing

Fish Consumption

Shellfish

Swimming

Boating

Aesthetics

Tourism

SAV/Habitat Loss

Assimilative Capacity

Expected Change (2020)

Confidence

Overall Human Influence

Confidence

Susceptibility

Nitrogen Yield

Low Dissolved Oxygen

SAV Loss

Nuisance/Toxic Blooms

Overall Secondary Level a Chlorophyll 

Epiphyte Abundance

Macroalgal Abundance

Overall Primary Level

N - none observed; L - low; ML - moderate low; M - moderate; MH - moderate high; H - high; U - unknown; IH - improve high; IL - improve low; NC - no change; WL - worsen low; WH - worsen high

RI - reasonable inference; MC - moderately certain; HC - highly certain; WC - water column; ENTR - entire watershed; EDA - estuarine drainage area; FDA - fluvial drainage area

Pacific (continued)

Coos Bay U U MMMM N N U L M L M M WL L YES U

Umpqua River U U L U U L N U U L ML L M L WL L U U

Siuslaw River U U M U U L L N U L M L M M WL L U U

Alsea River U U M U U L N N U L M L M M WL L U U

Yaquina Bay ML H M N N M L N N L ML L M L WL L U U

Siletz Bay U U U U U L N U U L ML L M L WL L U U

Netarts Bay U U M U U M N N U L M L H M WL L U U

Tillamook Bay U U L U U L N N U L M L M M WL L U U

Nehalem River U U L U U L N N U L M L M M WL L U U

Columbia River ML M H N N H N N L L L ML L L NC ML NO FDA √

Willapa Bay M M M N H H N M M M ML M L M WL M RI RI YES EDA √ √√

Grays Harbor M M M N H H N U M M ML ML L M WL M RI RI YES EDA √ √√

Puget Sound M M H N H H L L M M ML M L M WL M MC MC MC YES EDA √ √√

Hood Canal MH M H U U H M U N M MH M H L WH MH MC MC YES EDA √ √√

Whidbey Basin/Skagit Bay M M H U U H L U L L M ML M M WL M RI RI YES EDA √√ √

South Puget Sound MH M H U N H L U M M MH M H M WH MH MC MC MC MC YES EDA √√ √

Port Orchard System MH M H U H H L L M M M ML M M WL M RI RI YES EDA √√ √

Bellingham/Padilla/Samish Bays M M H U M H N N M M M ML M U WL M RI RI YES EDA √ √

Sequim/Discovery Bays M L H U H H L U M M M ML M U WL M RI HC YES EDA √ √
Appendix B: Table of Results

67

The individuals listed here contributed to the creation of this report. A check mark for a survey form indicates that a participant filled

out all or part of an initial data collection form for one or more estuaries. The regional assessment column indicates that the participant was involved in site visits or attendance at regional assessment workshops. Individuals noted for methods development and the

National Assessment Workshop columns contributed to the development of data aggregation methods and/or analyzed and reviewed

national-level assessments of the resulting data.

Survey Form

Regional 

Assessment

Methods 

Development

National 

Assessment

North Atlantic

Arnold Banner U.S. Fish and Wildlife Service √

Seth Barker Maine Dept. of Marine Resources √

Joceline Boucher Maine Maritime Academy √ √

Laurice Churchill Maine Dept. of Marine Resources √

Philip Colarusso U.S. Environmenal Protection Agency √

Canthy Coniaris University of New Hampshire

Michael Connor Massachusetts Water Resources Auth. √

Jerome Cura Menzie-Cura & Associates Inc. √ √

Lee Doggett Maine Dept. of Environmental Protection √ √

William Ellis Maine Maritime Academy √

Bernie Gardner University of Massachusetts √ √

Hap Garritt Woods Hole Oceanographic Institute √

Chris Garside Bigelow Laboratory for Ocean Sciences √ √

Diane Gould Massachusetts Bay Program √ √

Chris Heinig Intertide Corporation √

Charles Hopkinson, Jr. Woods Hole Oceanographic Institute √

John Hurst Maine Dept. of Marine Resources √

Kenneth Keay Massachusetts Water Resources Auth. √

Maureen Keller Bigelow Laboratory for Ocean Sciences √ √

Jack Kelly U.S. Environmenal Protection Agency √√ √

Peter Larsen Bigelow Laboratory for Ocean Sciences √√ √

Theodore Loder University of New Hampshire √√√√

Caroline Martorano University of New Hampshire

Lawrence Mayer University of Maine √

Bernard McAlice Darling Marine Center √

Mike Mickelson Massachusetts Water Resources Auth. √ √

Paul Mitnik Maine Dept. of Env. Protection √ √

Byard Mosher University of New Hampshire √

Carter Newell Great Eastern Mussel Farm √

Judith Pederson MIT Sea Grant √

David Phinney Bigelow Laboratory for Ocean Sciences √

Frederick Short University of New Hampshire √

John Sowles Maine Dept. of Env. Protection √ √

David Taylor Massachusetts Water Resources Auth. √ √

David Townsend Bigelow Laboratory for Ocean Sciences √

Robert Vadas University of Maine √

Middle Atlantic

Josephine Aller State University of New York at Stony Brook √

Charles App U.S. Environmenal Protection Agency √

Sima Bagheri New Jersey Institute of Technology √

Robert Biggs Roy F. Weston Inc. √

Donald Boesch University of Maryland - Horn Point √√ √

Henry Bokuniewicz State University of New York at Stony Brook √

Walter Boynton University of Maryland √ √√

Denise Breitburg Academy of Natural Sciences √

Thomas Brosnan National Oceanic and Atmospheric Administration √√ √

Claire Buchanon Interstate Commission on the Potomac River Basin √ √

Nick Carter Maryland Dept. of Natural Resources √

James Casey Maryland Dept. of Natural Resources √

Carl Cerco Army Corps of Engineers √

Jonathon Cole Institute of Ecosystem Studies √

Robert Connel New Jersey Dept. of Env. Protection √ √

Sherri Cooper Duke University √

David Correll Smithsonian Environmental Res. Cent. √ √

Elizabeth Cosper Cosper Environmental Services, Inc. √√ √

Joseph Costa Buzzards Bay Project √ √

Christopher D'Elia State University of New York at Albany √ √

Christopher DeAcutis Rhode Island Dept. of Env. Mgmt. √

Robert Diaz Virginia Institute of Marine Science √ √

Diana Domotor Maryland Dept. of the Environment √

Bill Eisele New Jersey Dept. of Env. Protection √ √

Deborah Tan Everitt Maryland Dept. of the Environment √ √

Thomas Fisher University of Maryland - Horn Point √

Anne Giblin Marine Biological Laboratory √

Howard Golub Interstate Sanitation Commission √

Sandy Groppenbucher New Jersey Dept. of Env. Protetion √ √

Appendix C: Participants
Appendix C: Participants

68

Survey Form

Regional 

Assessment

Methods 

Development

National 

Assessment

Middle Atlantic (continued)

Marilyn Harlin University of Rhode Island √

Donald Heinle CH2M Hill √ √

Frederick Hoffman Virginia Water Control Board √ √

Norbert Jaworski U.S. Environmental Protection Agency √

Tom Jones Salisbury State University √

Stephen Jordan Maryland Dept. of Natural Resources √

Renee Khan Maryland Dept. of Natural Resources √

Grace Klein-MacPhee University of Rhode Island √

Al Korndoerhfer New Jersey Dept. of Env. Protection √ √

Robert Magnien Maryland Dept. of Natural Resources √√ √

Thomas Malone University of Maryland - Horn Point √√√√

James Maughan CH2M HILL √

Bruce Michael Maryland Dept. of the Environment √ √

Doreen Monteleone New York St. Dept. of Economic Development √

Jon Morrison U.S. Geological Survey √

James Mummam New Jersey Dept. of Env. Protection √ √

Robert Nuzzi Suffolk County Dept. of Health Services √ √

Jay O' Reilly NOAA, National Marine Fisheries Service √

Paul Olsen New Jersey Dept. of Env. Protection √ √

Christine Olsen Connecticut Dept. of Env. Protection √

Robert Orth College of William and Mary √

Candace Oviatt University of Rhode Island √

John Paul U.S. Environmental Protection Agency √ √

Jonathan Pennock University of Alabama/Dauphin Island Sea Lab √√√√

Ernest Pizzuto Connecticut. Dept. of Environmental Protection √ √

Kent Price University of Delaware √

Ananda Ranasinghe Versar Inc. √

Louis Sage Bigelow Laboratory for Ocean Sciences √ √

James Sanders Benedict Estuarine Research Lab √

Sybil Seitzinger Rutgers University √

Valerie Shaffer Virginia Institute of Marine Science √

Frederick Short University of New Hampshire √ √

David Simpson Connecticut Dept. of Env. Protection √

Carl Sindermann Oxford Laboratory √

Theodore Smayda University of Rhode Island √

Paul Stacey Connecticut Dept. of Env. Protection √ √

R. Lawrence Swanson State University of New York at Stony Brook √

Robert Thomann Manhattan College √

James Thomas NOAA, National Marine Fisheries Service √

Elaine Trench U.S. Geological Survey √

Jefferson Turner University of Massachusetts-Dartmouth √

Steve Weisberg Versar Inc. √ √

Richard Wetzel College of William and Mary √ √

Robert Whitlatch University of Connecticut √

Gary Wikfors NOAA, NMFS/N.E. Fisheries Science Center √

Charles Yarish University of Connecticut √

South Atlantic

Merryl Alber University of Georgia √ √

Jim Alberts University of Georgia √ √

Clark Alexander Skidaway Institute of Oceanography √

Richard Alleman South Florida Water Management Dist. √

Dennis Allen University of South Carolina √

Richard Barber Duke University Marine Laboratory √

Diane Barile Marine Res. Council of East Florida √

Vincent Bellis East Carolina University √

Jackson Blanton Skidaway Institute of Oceanography √

Elizabeth Blood J. W. Jones Ecological Research Center √ √

Bob Brody St. Johns River Water Mgmt. Dist. √ √

Deborah Bronk University of Georgia √

Ramesh Buch Dade County Env. Resources Mgmt. √

JoAnn Burkholder North Carolina State University √

Larry Cahoon Univ. of North Carolina at Wilmington √ √

David Chestnut South Carolina Dept. of Health & Env. Control √√√

Daniel Childers Nat. Marine Fisheries Service/NOAA √

Robert Christian East Carolina University √

John Cooper East Carolina University √

Terry Davis Florida Dept. of Environmental Reg. √

Betsy Deuerling City of Jacksonville √

Phillip Dunstan College of Charleston √

Bob Frease Marine Resources Council of East Fl. √

Greg Graves Florida Dept. of Environmental Reg. √

Guy Hadley Florida Dept. of Environmental Reg. √

Jess Hawkins III North Carolina Div. of Marine Fisheries √

Jim Henry Georgia State University √

John Higman St. Johns Water Management District √

Robert Hodson University of Georgia √ √

Fred Holland South Carolina Dept. of Wildlife and Marine Res. √√ √
Appendix C: Participants

69

Survey Form

Regional 

Assessment

Methods 

Development

National 

Assessment

South Atlantic (continued)

Jeff Hyland NOAA, National Ocean Service √

William Kirby-Smith Duke University √

David Knott South Carolina Wildlife & Marine Res. √

Alan Lewitus University of South Carolina, Baruch Institute √

Wayne Magley Florida Dept. of Environmental Reg. √ √

Michael Mallin Univ. of North Carolina - Wilmington √√ √

Susan Markley Dade County Environmental Resources Mgmt. √

Hank McKellar University of South Carolina √√ √

Mary Ann Moran University of Georgia √

James Nelson Skidaway Institute of Oceanography √

Jimmie Overton North Carolina Division of Env. Mgmt. √

Hans Paerl University of North Carolina √

James Pinckney University of North Carolina - Chapel Hill √

Lawrence Pomeroy University of Georgia √

Joe Rudek North Carolina Environmental Defense Fund √

Russell Sherer South Carolina Dept. of Health and Env. Cntrl. √

Donald Stanley East Carolina University √√√

Stuart Stevens Georgia Dept. of Natural Resources √

Steve Tedder North Carolina Div. of Environmental Management √

Patricia Tester NOAA, National Marine Fisheries Service √

Bob Van Dolah South Carolina Dept. of Wildlife and Marine Res. √√√√

Peter Verity Skidaway Institute of Oceanography √√ √

Robert Virnstein St. Johns River Water Mgmt. Dist. √

Randy Walker Skidaway Institute of Oceanography √

Cecelia Weaver Dade County Env. Resources Mgmt. √

A. Quinton White Jacksonville University √

Richard Wiegert University of Georgia √

Herbert Windom Skidaway Inst. of Oceanography √

John Windsor Jr. Florida Institute of Technology √ √

Gulf of Mexico

Neil Armingeon Lake Pontchartrain Foundation √

Don Axelrad Florida Dept. of Environmental Protection √

Bruce Baird U.S. Army Corp of Engineers √

Ronnie Best National Biological Survey √

Tom Bianchi Tulane University √ √

Jan Boydstun Louisiana Dept. of Env. Quality √

Joe Boyer Florida International University √

Jim Bowman Texas Natural Resources Cons. Comm. √

David Brock Texas Water Development Board √ √

Fred Bryan Louisiana State University √

David Burke Gulf Coast Research Laboratory √

Dave Buzon Texas Parks and Wildlife Department √

Tom Cardinale Hillsborough County Env. Prot. Comm. √

Sneed Collard University of West Florida √

Emelise Cormier Louisiana Dept. of Env. Quality √

Michael Dagg Louisiana Universities Marine Consortium √

John Day Louisiana State University √

Charly Demas U.S. Geological Survey √

Richard DeMay Barataria/Terrebonne National Estuary Program √

Dennis Demcheck U.S.Geological Survey √

Hudson Deyoe Texas A&M University √

Robert Dickey Gulf Coast Research Laboratory √

Juli Dixson University of Southern Mississippi √

Kelly Dixon Mote Marine Laboratory √

Peter Doering South Florida Water Mgmt. Dist. √ √

Quay Dortch Louisiana Universities Marine Consortium √ √

Tom Doyle National Biological Survey √

Ken Dunton University of Texas √

H. Lee Edmiston Apalachicola Natl. Est. Research Reserve √ √

Ernest Estevez Mote Marine Laboratory √√ √

Janice Fellers Suwannee River Water Mgmt. District √

Nichole Fisher Texas A&M University √

David Flemer U.S. Environmental Protection Agency √√√√

James Fourqurean Florida International University √

Gary Gaston University of Mississippi √ √

Cynthia Gorham-Test U.S. Environmental Protection Agency √

Holly Greening Tampa Bay Estuary Program √ √√

George Guillen Texas Water Commission √

Joe Hand Florida Dept. of Environmental Protection √

Albert Hindrichs Louisiana Dept. of Env. Quality √

Dan Haurnet South Florida Water Mgmt. Dist. √

Richard Iverson Florida State University √ √
Appendix C: Participants

70

Survey Form

Regional 

Assessment

Methods 

Development

National 

Assessment

Gulf of Mexico (continued)

J. O. Roger Johansson City of Tampa Bay Study Group √

Lori Johnson National Biological Survey √

Clifford Kenwood Lake Pontchartrain Foundation √

Larry Land U.S. Geological Survey √

Brian LaPointe Harbor Branch Oceanographgic Inst. √ √

Graham Lewis North West Florida Water Mgmt. District √

Skip Livingston Florida State University √

Steven Lohrenz University of Southern Mississippi √

Rodney Mach U.S. Army Corp of Engineers √

Robert Mattson Suwannee River Water Mgmt. Dist. √ √

Jerry McLelland Gulf Coast Research Laboratory √

Ben McPherson U.S. Geological Survey √

Russell Miget Texas A&M University √

Cynthia Moncrieff Gulf Coast Research Laboratory √

Paul Montagna University of Texas at Austin √ √

Ralph Montgomery Environmental Quality Lab √

Gerold Morrison S.W. Florida Water Mgmt. District √ √

Harriet Perry Gulf Coast Research Laboratory √

Michael Perry Southwest Florida Water Mgmt. District √

Michael Poirrier University of New Orleans √ √

Gary Powell Texas Water Development Board √ √

Warren Pulich Texas Parks and Wildlife Department √

Nancy Rabalais Louisiana Universities Marine Cons. √ √

Chet Rakocinski Gulf Coast Research Laboratory √

Donald Ray Florida Dept. of Environmental Reg. √

Donald Redalje University of Southern Mississippi √ √

Bill Rizzo National Biological Survey √

Patrick Roques Texas Natural Resources Cons. Comm. √

Dugan Sabins Louisiana Dept. of Env. Quality √ √

William Schroeder University of Alabama √ √

James Seagle Florida Dept. of Natural Resources √ √

Frank Shipley Galveston Bay Natl. Estuary Program √

Thomas Smith III Rookery Bay Natl. Est. Research Reserve √

Kerry St. Pe' LA Dept. of Environmental Quality √

Dean Stockwell University of Texas at Austin √ √

J. Kevin Summers U.S. Environmental Protection Agency √√√

Carmelo Tomas U.S. Environmental Protection Agency √

David Tomasko S.W. Florida Water Management District √√ √

R. Eugene Turner Louisiana State University √ √

Steven Twidwell TNRCC/Water Plan. & Assmnts. Div. √

Robert Twilley University of Southwestern Louisiana √√ √

Gabriel Vargo University of South Florida √ √

Richard Volk Corpus Christi Bay National Estuary Program √

Michael Waldon University of Southwestern Louisiana √

Albert Walton Jr. Florida Dept. of Environmental Reg. √

William Wardle Texas A&M University at Galveston √

Jeff Waters Lake Ponchartrain Basin Foundation √

James Webb Jr. Texas A&M University at Galveston √

Jay Zieman University of Virginia √

Pacific

Jim Arthur Bureau of Reclamation √

Shirley Birosik Los Angeles Water Quality Control Bd. √ √

Milton Boyd Humboldt State University √

Karleen Boyle University of California - Los Angeles √

Donald Brown California St. University at Long Beach √ √

Randall Brown California Dept. of Water Resources √

Barbara Ann Butler Oregon Institute of Marine Biology √

Jane Caffrey Elkhorn Slough Nat. Est. Research Reserve √

John Chapman Hatfield Marine Science Center √

James Cloern U.S. Geological Survey √

Brian Cole U.S. Geological Survey √ √

Eugene Collias Northwest Consultant Oceanographers Inc. √

Barry Collins California Dept. of Fish and Game √

Andrea Copping Washington Sea Grant √

Frank Cox Washington Dept. of Health √

Clayton Creech Hatfield Marine Science Center √

Scott Dawson Santa Ana Regional Water Quality Control Board √

Andrew DeVogelare Elkhorn Slough Natl. Est. Research Reserve √

Robert Emmett NOAA, National Marine Fisheries Service √

Peggy Fong University of California - Los Angeles √ √
Appendix C: Participants

71

Survey Form

Regional 

Assessment

Methods 

Development

National 

Assessment

Pacific (continued)

Jon Graves Columbia R. Estuary Study Task Force √

Michael Graybill South Slough Nat. Est. Research Reserve √

John Hannum North Coast Regional Water Quality Control Board √ √

Jan Hodder Oregon Institute of Marine Biology √

James Hollibaugh San Francisco State University √

Carol Janzen University of Delaware √

John Johnson Oregon Dept. of Fish and Wildlife √ √

Deborah Johnston California Dept. of Fish and Game √ √

Michael Josselyn San Francisco State √

Christopher Kinner Irvine Ranch Water District √

Eric Klein Orange Co. Public Facilities & Resources Dept. √

Katie Kropp Morro Bay National Estuary Program √

Gregg Langlois California Dept. of Health Services √

Peggy Lehman California Dept. of Water Resources √

Lisa Levin Scripps Institution of Oceanography √

Michael Martin California Dept. of Fish and Game √

Larry Marxer Oregon Dept. of Environmental Quality √

Gregory McMurray Oregon Dept. of Environmental Quality √√√

Peter Michael San Diego Water Quality Control Board √ V

Bruce Moore Orange Co. Public Facilities & Resources Dept. √

Chad Nelsen Oregon Dept. of Land Cons. & Dev. √

Avis Newell Oregon Dept. of Environmental Quality √

Jan Newton Washington State Dept. of Ecology √√√√

Frederic Nichols U.S. Geological Survey √

James Nybakken Moss Landing Marine Laboratory √

Don Oswalt Oregon Dept. of Land Cons. & Dev. √

Bill Paznokas California Dept. of Fish and Game √

Greig Peters San Diego Water Quality Control Board √

Bill Peterson Hatfield Marine Science Center √

Chris Prescott Puget Sound Water Quality Authority √

Harlan Proctor California Dept. of Water Resources √

Don Reish California State University √

Jack Rensel University of Washington √

Curtis Roegner Oregon Institute of Marine Biology √

Greg Ruiz Smithsonian Env. Research Center √

Steve Rumrill South Slough Nat. Est. Research Reserve √

Mary Beth Saffo University of California at Santa Cruz √

Kathleen Sayce Shoalwater Botanical √

Larry Schemel U.S. Geological Survey √

Lynda Shapiro Oregon Institute of Marine Biology √

Randy Shuman Metropolitan King County √ √

Mark Silberstien Elkhorn Slough Nat. Est. Research Reserve √

Lawrence Small Oregon State University √

David Specht U.S. Environmental Protection Agency √

Pete Striplin Striplin Environmental Assoc. √

Barbara Sullivan Oregon State University √

Kathy Taylor Columbia R. Estuary Study Taskforce √

Ronald Thom Battelle/Marine Sciences Laboratory √√ √

Bruce Thompson San Francisco Estuary Institute √

Ken Thompson Irvine Ranch Water District √

Tim Unterwegner Oregon Dept. of Fish and Wildlife √

William Winchester North Coast Reg. Water Quality Control Board √

Karen Worcester Cent. Coast Reg. Water Quality Control Board √ √

Jack Word Battelle Ocean Sciences √

Joy Zedler University of Wisconsin √ √

National

Richard Alexander U.S. Geological Survey √

Darrell Brown U.S. Environmental Protection Agency √ √

Andrew Robertson National Oceanic and Atmospheric Administration √ √

Dick Smith U.S. Geological Survey √

Richard Valigura National Oceanic and Atmospheric Administration √ √

Terry Whitledge University of Alaska Fairbanks √√√√