# 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. Thisreport, 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

N A T IONALO CEA NIC
ANDA T M O SPH ERICAD MINISTRA TIO N U

.S

.DEPA R T M E N T

OFC OMMER CE### Richard 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 ScienceWe 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 Alexanderand 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, NOAAThis report is the culmination of almost seven years of effort to assess comprehensively the scale, scope, and characteristics of nutrient enrichment andeutrophic 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. coastalwaters. 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; reauthorizationof 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 ofthe 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 andresource managers. I encourage you to use this work to stimulate further efforts to protect our natural resources.

iv 

# Foreword

### Eutrophication is the accelerated productionof 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 lossof submerged aquatic vegetation. These impacts are interrelated and usually viewed as having a negative effect on water quality and ecosystem health. Eutrophication has beenrecognized as a problem in freshwater systems for many years, but only in the past three decades has concern grown about thewidespread occurrence of eutrophic conditions in estuarine systems. Due to the complexity of the phenomena and the lack of consistent national data sets, the severity andextent 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 conditionsin 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 basedprimarily 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 percentof the estuarine surface area of the coterminous United States, plus the MississippiRiver 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 ofimproving 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 EutrophicationHigh 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 moderateto 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-leveleutrophic 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 managersincludes spatial and temporal information about eutrophication symptoms, including chlorophyll a, macroalgae, epiphytes, dissolved oxygen, submerged aquatic vegetation, and nuisance/toxic algaesurvey 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. 

## Impaired Uses of Estuaries 

# 3 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 atrisk 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 timefor 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 shouldbe priorities for preventive management. These estuaries represent approximately 3% of the national estuarine surface area. All of the typical point and nonpoint pollution sourceswere 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.



## Future Eutrophic Conditions 

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

Assessment Data: projected population growth estimatesadapted from the U.S. Census Bureau and NOAA susceptibility data Description: Experts at the National Workshop usedpopulation 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.


## Data Gaps and Research Needs 

# 6 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 todate, 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. 

## Data Gaps and Research Needs, continued 

# 6

Toward A National Strategy 

# 7 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 facilitateddiscussions with the participating estuarine eutrophication experts. 

### The National Assessment process confirms thatmuch 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 isneeded, 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, andcharacterization 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 condition s, this is usually a slow process that results in healthy and productive ecosystems. In recent decades, however, a variety of human activities has greatl y 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. Lighter freshwater Denser seawater inhibits mixing with upper oxygen-rich layer. Oxygen from wave action and photosynthesis mixes with upper fresher water 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 ProblemEutrophication refers to a process in which the addition of nutrients to water bodies, primarily nitrogen and phosphorus, stimulates algal growth. Thisis 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, suchas 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 growthof 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 algalspecies 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 activitieshave 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, andBlack Seas, to the estuaries and coastal waters of Japan, China, and Australia. Eutrophic symptomshave also been observed in the United States, including the Chesapeake Bay, Long Island Sound, and thenorthern Gulf of Mexico. More recently, it has become clear that nearly all U.S. estuaries exhibit somelevel 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 symptomsmay also cause risks to human health, including serious illness and death, that result from the consumption of shellfish contaminated with algal toxins, orfrom direct exposure to waterborne or airborne toxins. It should be noted that although nutrients causeeutrophic 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 increasedwater temperatures, causing lower dissolved oxygen with no changes in nutrient inputs. At the sametime, 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 environmentalproblems. For instance, extensive losses of submerged aquatic vegetation and the associated loss of fish habitat have occurred, many coastal waterbodies 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 ofeutrophication 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 withinthe 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 AssessmentSince its inception in 1992, NOAA’s National Estuarine Eutrophication Survey has synthesized the best available information on eutrophication-relatedsymptoms 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 majorU.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 toconsistently 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) todevelop 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 amongestuaries, as well as facilitate summaries of national and regional results. To accomplish this, two obstacles—data quality and a lack ofmethodology 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 forall 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 31other systems, some of the symptom data provided by the experts was rated as “speculative” becauseit was based on spatially or temporally limited field observations. The overall confidence levels for these estuaries was therefore assessed aslow. The evaluations for each symptom were carried through the assessment process to provide a basisfor assigning a confidence rating to the overall assessment of eutrophic conditions. This confidenceevaluation is important, because incomplete or uncertain data were sometimes included in the overallassessment 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 severalquestions while determining the best way to integrate the existing data:

Are all eutrophic symptoms and their characteristics equally important? Should all 16 symptomsbe 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 arepresent “high” eutrophic symptoms in all estuaries? The Eutrophication Model. To help overcome these obstacles and properly interpret the information, theCore 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. Whilethis 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 aas an indicator), epiphyte abundance, and macroalgae, represent the first possible stage ofwater-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 biologicaland 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 concentrationsmay be very high while dissolved nutrient concentrationsare low. This scenario is common during peak phytoplankton production because theseorganisms 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 submergedaquatic 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 primarysymptoms. 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 overallsecondary value for the estuary. This weights the secondary symptoms higher than the primary symptoms, because the secondary symptoms take longerto 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 dividedinto 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 RiverPlume actually fell at either extreme of this continuum, where the numerical scoring systemsare 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: Category Assigned Score Range 

### 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. Low > <

0 0.3 0.3 0.6 > < Moderate 1 0.6 < > 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, whichsuggests that they are in the early stages of eutrophication and may be on the edge of developing moreserious 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 secondarysymptoms 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 islonger 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 modeldoes 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 inNOAA’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 whythese 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 themagnitude 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 theguidance 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 modelwas 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 betweeneutrophic 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 thevolume 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 processesmay 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 highcoastal 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 basicunderstanding 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 tonational 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, andnonagricultural sources. In addition, NOAA provided information on coastal population and land usage, which were used as comparative estimators of loading. Estuarine susceptibility estimates werebased 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, weremore 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 thesesymptoms, 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 andAgricultural 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 impairthe 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 includedrecreational 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 theyear 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 inputsand 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 theability 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 thenation’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. Themost 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 ofthe 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 thelevel 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 onlymeans 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 someof 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 ofoverall 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 coastlinesexhibited high levels of eutrophic conditions (Figures 6 and 7). This means that in these estuaries, oneor more symptoms occurred at problem levels every year, or persistently, across a major part of eachestuary. 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 expr essions of eutrophic conditions. The Middle Atlantic and Gulf of Mexico have the highest per centages of estuaries with high eutr ophic conditions. The Pacific and South Atlantic r egions

contain the highest per centage of estuaries that lack sufficient information to confidently assess eutr ophic conditions. An additional forty estuaries (not
shown) have moderate levels of eutr ophic 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 ofmicroscopic 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 aquaticvegetation by encrusting leaf surfaces and thereby reducing the light available to the plant leaves. Macroalgaeare 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 oxygenoccurs 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 whenlight 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 bloomsare 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. Abouthalf of these estuaries were located in the South Atlantic and Pacific regions. In more than 80 percent of estuaries with high andmoderate levels of eutrophic conditions, the assessment confidence was high; conversely, confidence was high in fewer than half of the systems assessedas 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. Theimmediate 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, anestuary is in the first stages of displaying undesirable eutrophic conditions. High expressions of chlorophyll aoccurred in 39 estuaries, high expressions of macroalgal abundanceoccurred 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 maybe 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 aand macroalgae were observed in estuaries of all regions (Figure 9). While high levels of primary symptoms are strongindicators 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. Thisfinding is important because these symptoms can have serious consequences, including negative impacts on commercialfish 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 exhibitedmoderate 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 inthe Gulf of Mexico, Middle Atlantic, and South Atlantic regions. These geographical differences maybe 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 andhuman-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 potentialmanagement targets. The data for these ancillary assessments were not as robust, and were less rigorously reviewed, than the Eutrophication Surveydata, 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 consideredthe 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 overalllevel 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, nitrogenvalues were used as the primary estimates of nutrient inputs, and information on population densityand 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 bemade. Many estuaries assessed as having high levels of overall eutrophic conditions also had high susceptibility and moderate to high levels of nutrient

### 14 National Overviewinputs. These estuaries are very sensitive to nutrient inputs, and as a result, many were assessed as having a high level of human-related influence onthe 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 ofeutrophic 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 ashaving 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 aslow 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 theseestuaries were lower susceptibility and lower nitrogen inputs; 31 of these estuaries had moderate or low nitrogen inputs, and 28 had moderate or lowsusceptibility. In these systems, natural characterisFigure 10. Influencing factors on the expression of eutrophic conditions

Estuarine Susceptibility The estuarine susceptibility estimates are based on estuarineflushing 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 datasets 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 overallnutrient 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 influ ence the expression of eutrophic conditions in the nation’s estuaries. The purpose was to develop an understanding of why eutrophic cond itions 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 quant ities 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)

2 (1) 8 (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 eutrophicconditions 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, orbetween 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 andhigh 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 lowdue to tidal ranges greater than six feet, and nitrogen inputs are generally low due to low populationdensities and densely forested watersheds. The overall eutrophic conditions in some of these estuaries were assessed as high because toxic blooms occurredeach 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 havemoderate to high expressions of at least one secondary symptom of eutrophication is of considerableimportance, 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 toxicblooms. 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 doesnot directly address economic losses, however, seasonal economies may suffer when eutrophic symptoms occur during the height of the tourist and/orfishing seasons. The cost of implementing strategies to reduce nitrogen inputs may also be considerable. For example, the U.S. Environmental Protection A gency’s Long Island Sound Study reported in1998 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 RegionCommercial/RecreationalFishingFish**Consumption**ShellfishSwimmingBoatingAestheticsTourismNumber ofEstuaries WithImpaired Uses

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 likelyto 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 ofeutrophic symptoms (Figure 11). Although this information is qualitative, it is still useful in understanding the nature of impaired uses on a nationalbasis. In all, some type of use impairment was identified in 69 estuaries. The most frequently reportedimpairments 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 assimilativecapacity—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 generalworkshop 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 highsusceptibility (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 recommendedtarget for the Pacific, Gulf of Mexico, and South Atlantic regions; wastewater treatment plants were important in the North Atlantic; and agriculture andatmospheric sources were most frequently recommended in the Middle Atlantic. Notable among thepoint 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 almostexclusively for the Gulf of Mexico and Middle Atlantic regions. Another important nonpoint source identified as needing management action in theSouth 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 ofpopulation 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 mostpart, 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 samein 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

RegionWaste WaterTreatment PlantsCombinedSewer OverflowOnsite DisposalIndustryAnimalOperationsUrbanAgricultureForestryRangeAtmospheric

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 Grays Harbor Willapa Bay CoquilleRiver Rogue River Siuslaw River Umpqua River Coos Bay Siletz Bay Yaquina Bay Alsea River Nehalem River Tillamook Bay Netarts Bay Bellingham/Padilla/

Samish Bays Sequim/Discovery
Bays Worsen Improve Conditions Expected To: Future Eutrophication Trends (2020) 

### Figure 13. Expected trends in eutrophication through 2020
Experts at the National Assessment W orkshop determined that conditions ar e expected to worsen in mor e than half of the nation’ s estuaries, and along all

of the coasts, by 2020. However , the experts cautioned that uncertainty is inher ent in these predictions and that they may be unduly pessimistic. A number

of factors that affect eutr ophic conditions may change over time, making it difficult to pr edict with substantial certainty the ultimate effect of population growth on nutrient loadings and the subsequent expr ession 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. 1970to 1995) was based on data from NOAA’s Estuarine Eutrophication Survey. These data areless certain, and the assessments were less rigorously reviewed at the National AssessmentWorkshop. 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 forwhich conditions improved. For dissolved oxygen, conditions improved in more estuaries than those that worsened. Overall, eutrophicconditions worsened in 48 estuaries and improved in 14. In 26 systems, there was no trend in overall eutrophic conditions since 1970. Mostof the estuaries that showed overall improvement were located in the Gulf of Mexico. Thegreatest number of estuaries in which conditions worsened were in the Gulf of Mexico and Middle Atlantic regions. Worsening trends have been attributed to ageneral increase in population density in estuarine watersheds. Some of these estuaries arehistorically 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 andSarasota 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 alsoneed 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 ofnutrient 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 whichthe 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 furtherclarification. Climate change, specifically global warming, will affect water levels, circulation, temperature and salinity, all of which will have an effect on thesusceptibility 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 predictivemodels 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 cond itions; 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 tovariations 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 var y greatly among estuaries, and identifiable subregional differences occur in response to inputs. Therefore, in addition to region al 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-pointingarrow. 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 wasbased 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 overalleutrophic 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 susceptibilityvalues for each estuary to determine the overall influence of human activities on the development of eutrophic conditions. The overall human influenceis 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 NationalAssessment 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 expertsreviewed 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 trendsMore 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 theeutrophic 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 todevelop 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 ofthe estuarine systems, with six being in the high category. Estuaries with these conditions were locatedalong 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
awas expressed at moderate levels for a majority of estuaries; macroalgal abundance problems occurredin 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 eutrophicconditions, nuisance/toxic algal blooms and overabundance of macroalgae were the principle symptoms contributing to the observed overall condition. Moderate expression of chlorophyll aand low expression of depleted dissolved oxygen were also observed in most of the systems with high eutrophicconditions, 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 coastalshoreline 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 arecharacteristic 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 berelated to point-source controls and declining Atlantic Menhaden runs. The confidence levels for the assessment of eutrophic conditions were low for four estuaries. Informationwas 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 tobe 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 nutrientinputs 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 coastalsystems is from offshore coastal waters. Consequently, many of the eutrophic symptoms expressed in the region, such as toxic algal blooms, arethought to be primarily natural conditions. Eutrophic

Condition

Kennebec/Androscoggin Rivers Chlorophyll a Epiphytes Macroalgae SAV Loss Low Dissolved Oxygen Nuisance/

Toxic Blooms

Estuary 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 ConcernsThe most frequently noted nutrient sources to target for management efforts were wastewater treatment plants and combined sewer overflows. Urbanrunoff, agriculture, aquaculture, and atmospheric inputs were also identified as sources of concern, but in relatively few estuaries.


## Future Outlook to 2020By the year 2020, eutrophication symptoms are expected to worsen in about one-third of the systems, primarily due to increased nutrient inputs frompopulation 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 systemswere noted to have low confidence levels for assessment. Important data and research needs generally includeimproved 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 isneeded to assess the effects of winter-summer population changes on eutrophic conditions. ditions, only one, Boston Harbor, had high humaninfluences. 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 astoxic 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-areaclosures 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 Susceptibility Nitrogen Input Overall Human Influence

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 imp acts 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 todevelop 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. Theexpression 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 nutrientinputs; 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 ofeutrophic conditions, and an additional five showing moderate conditions.

high expressions of primary symptoms. The five estuaries exhibiting moderate eutrophic conditionsdisplayed similar symptoms, except that the secondary symptoms were somewhat less severe. An improvement in at least one symptom is notedas the most recent trend in close to half of the estuaries. Unfortunately, most of these improvements aremodest, 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 controlshould be maintained and fortified. In the Chesapeake Bay and its tributaries, for example, submerged aquatic vegetation suffered severe declinesin 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 useis 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 pervasivein 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
ahad 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 problemsin 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 eutrophicconditions 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 Epiphytes Macroalgae SAV Loss Low Dissolved Oxygen Nuisance/

Toxic Blooms

Estuary 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 eutrophicconditions were generally high, although three estuaries were rated as low. The Connecticut River hadthe least data and the lowest confidence. Information was sparsest for trends in epiphyte abundance. 

## Influencing Factors The expression of severe eutrophic conditionstended 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 BuzzardsBay and Delaware Bay, exhibited fewer impacts (although these systems may have had small, more localized areas of high symptoms). Nitrogen inputswere 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 overallhuman influence were generally high; three estuaries were rated as low. 

## Impaired Uses The loss of habitat (primarily submerged aquaticvegetation) 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 managenutrient 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 severelyin 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 Susceptibility Nitrogen Input Overall Human Influence

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 neededto 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 resourcesin 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 todevelop 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 wastewatertreatment 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 Figure 22. Eutrophic conditions and symptoms 

### The South Atlantic region includes 22 estuaries, encom- passing more than 4,440 square miles of water surface area. The region is comprised of extensive barrier and seaislands that parallel the shoreline. The coastal environment consists of shallow lagoonal estuaries, extensive tidalmarshes and drowned river valleys. Estuarine circulation patterns are dominated mainly by wind and seasonalfreshwater 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 (1.5-7.0feet) 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. Majorpopulation 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 theSt. 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
ahad the most pronounced expression in five estuaries located in North Carolina and Florida. Of the secondary symptoms, depleted dissolved oxygenwas 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 aand 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, theconfidence 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 halfof 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 Epiphytes Macroalgae SAV Loss Low Dissolved Oxygen Nuisance/

Toxic Blooms

Estuary 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, lowtidal 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 theestuaries 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, largeanimal 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 2020Based on the experts’ knowledge of watershed activities, population trends, and nutrient-loading estimates, 12 estuaries were predicted to develop worsening eutrophication conditions through 2020; atpresent, 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 bloomsever 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 NeedsThe South Atlantic is generally a poorly studied region. The confidence level of the assessment of overall eutrophic condition was low for 12 systems, andan additional six were specifically identified as requiring improvements in basic monitoring. The need fordata in this region is critical, given the projected increases in population and the susceptibility of many Eutrophic Condition

Moderate Low Susceptibility Nitrogen Input Overall Human Influence

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 dataon 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 loadingin 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 A tlantic. 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 13 14 15 16 17 18 19 20

21

22 23 24 25 26 27 28 29 30 31 32 33
34

35 36

37 38

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 todevelop or become more pronounced by 2020.
Improve: symptoms are expected to decline through 2020.

### 33 Gulf of Mexico Figure 25. Eutrophic conditions and symptoms 

### The Gulf of Mexico region includes 37 estuaries plus the Mississippi River Plume, encompassing more than 24,000square 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 arehighly diverse, consisting of unrestricted open bays, semienclosed lagoons, tidal marshes and delta complexes. Thefresh 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 warmerthan 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 toestuaries 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 werecharacterized 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, lowdissolved 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 per

## Of all regions, the Gulf of Mexico has the greatest percentage of estuarieswith 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 warmwaters result in higher levels of expression of eutrophic conditions. Eutrophic

Condition Symptom Expression Chlorophyll a Epiphytes Macroalgae SAV Loss Low Dissolved Oxygen Nuisance/

Toxic Blooms

Estuary 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 Figure 26. Eutrophic conditions and influencing factors 

### vasive, occurring in 28 estuaries, eight of which 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 theobserved 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 tohigh 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 tohigh, 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 highfor 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 correspondedwell 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 Susceptibility Nitrogen Input Overall Human Influence

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 UsesImpaired uses were difficult to define as being directly related to eutrophication. Results from theWorkshop, 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 physicalmakeup 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, andMermentau 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 recycledwithin 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 forbetter 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 todevelop or become more pronounced by 2020.
Improve: symptoms are expected to decline through 2020.

### 37 Pacific Figure 28. Eutrophic conditions and symptoms 

### The Pacific region includes 39 estuaries, encompassing 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 environmentssupport estuaries, bays and lagoons. Estuaries are typically small and separated by large distances. Estuarine circulation patterns are dominated mainly by seasonalfreshwater inflow in Southern California and by freshwater inflow and tides in the larger estuaries of centralCalifornia 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 thenorthern 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
awas expressed at high levels in 11 systems, most ofthem in Southern California and northern Washington. Macroalgal abundance was observed at moderate to high levels in 13 estuaries, most of them alsofound 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 higheutrophic conditions were elevated levels of chloro

## The Pacific region, more than any other, is characterized by insufficientdata. 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 Epiphytes Macroalgae SAV Loss Low Dissolved Oxygen Nuisance/

Toxic Blooms

Estuary 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 Figure 29. Eutrophic conditions and influencing factors 

### phyll a, coupled with various combinations of 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 the27 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 InfluenceIn 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 theTijuana Estuary, Newport Bay, San Pedro Bay, Anaheim Bay and San Francisco Bay. Three of these— Newport, Anaheim and San Pedro—are among thetop 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 systemswere generally small, with good flushing capabilities, and nutrient loading appeared to be moderate. In general, restricted circulation and moderate tohigh 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 SouthernCalifornia and Washington; impaired uses were unknown in Oregon and northern California. Eutrophic

Condition

Moderate Low Susceptibility Nitrogen Input Overall Human Influence

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 andforestry. 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 ColumbiaRiver—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 2020Thirty-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 expectedto 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 inthese areas. In addition, research is needed to determine the fate of nutrients and their eventual impactson 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 highin 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 conditionswere 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 whichvery 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 theirimpacts 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 leastone 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 mostfrequently reported as being impaired were commercial fishing and shellfish harvesting. Recreational fishing, swimming, and boating, all of which contributeto 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 surfacearea 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 thegreatest number of estuaries (43 and 46, respectively). 

## Key Findings 

# Conclusions

### 42 Conclusions 

## Influencing Factors on EutrophicationMost 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). Ofthe 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, especiallywhen nutrient inputs are not extremely high. Furthermore, of the 38 estuaries with a low expression ofeutrophic 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, thenit 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, conditionscan be moderated or reversed with appropriate management action. The success of these efforts depends in parton 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 influenceand 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 theseestuaries 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 thoseestuaries 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, thathave 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 ConcernsExperts 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 arehighly susceptible to retaining nutrients and are located in watersheds in which significant populationgrowth is projected. Most of these estuaries are located in the South Atlantic and Gulf of Mexico regions. Only eight (6%) of 138 estuaries are expectedto 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 futureoutlook 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 inplace, 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 reducenutrient inputs in order to counteract the effects of expected population growth and other factors that promotethe 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 managementtargets. 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 theMiddle 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 138estuaries, 39 (nearly 30%) were rated as “low confidence” for the assessment of eutrophic conditions. The factors leading to low confidence include oneor 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 asland use and population. This information is necessary to assess overall eutrophic conditions, to establish baseline conditions, and to track the conditionof 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 sourcesof 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 thetriggering of toxic algal blooms. Better characterization of basic circulation patterns would increase understanding of how nutrients are processed oncethey 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 doneto 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 clarifythe linkages between eutrophication and impacts on estuarine resources, including fisheries, recreation and tourism, and risks to human health. The National Assessment process confirms thatmuch remains to be done to adequately characterize nutrient pressure on estuaries. Betterquantification 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 isneeded, 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 manage

ment, 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 estuarineeutrophication is indeed a problem of national significance. It indicates that human-related nutrientsources, 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 therapid advance of scientific understanding of the linkages between eutrophication and marine resources.A national strategy is needed, especially one that effectively integrateswatershed-specific approaches to assessment and management into a comprehensive approach.


## How Can These Results Be Used? National Assessment results can beused 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 thatare in serious condition should be priorities for management actions; those in less serious condition, but at risk ofdeterioration, should be closely monitored, and efforts should be made toidentify 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 willallow 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 MANAGEMENT RESPONSE ENVIRONMENTAL TRIAGE

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 associatedeutrophic conditions have been identified as a critical problem in the nation’s estuaries for over three decades.

As the 20 th

## century comes to a close, a cogent and comprehensive national strategy still remains elusive. likely benefit from, treatment. By such sorting, aframework 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 eutrophicsymptoms 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 nutrientcontrol 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 remediationplans. For instance, different plans should be implemented for those estuaries that, although in seriouscondition, might be improved with additional management effort; those in less serious condition but at risk of worsening that should be closely monitoredand 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 ofeutrophic conditions, the influence of human activities, and the natural sensitivity to nutrients, to assure the most effective results within the constraintsof 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 actuallyknown 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) andfixed, continuous monitoring that emphasizes temporal resolution (both short- and long-term) and the tracking of nutrients and eutrophic symptoms. Thedata base and framework can also be used to determine how monitoring programs can be integratedacross scales (local, regional, national) and across media (water, air, land).
The assessment results also reconfirm the need formonitoring 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. Observationalsystems, 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 estuariesas mixing zones between rivers and oceans is invaluable for determining where to direct many researchefforts. 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 withlocal and regional estuarine scientists and coastal resource managers. Two workshops held in January 1991 consisted of presentations by invited speakersand discussions of the measures and effects associated with nutrient problems. The purpose was tofacilitate 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 developingrecommendations 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 incompatibledata 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 andestuarine 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 eutrophicationThis 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 fromdiscussions 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 overa 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 ofexisting 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 ( >2m g/l ≤5m g/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:

• Limitin g factors to al g al biomass ( N, P, Si, li g ht, other) • S p atial covera g e 1 , Months of occurrence, Fre q uencyof occurrence 2

• Secchi disk de p ths: Hi g h ( <1m ) , Medium ( 1 ≥ m, ≤ 3m ) , Low ( >3m ) , Blackwater area • Concentrations 3,4

• Concentrations: Problem (significant impact upon biological resources) No Problem (no significant impact)

• Months of occurrence, Fre q uencyof occurrence 2

• Occurrence

• Dominant s p ecies • Event duration ( Hours, Da y s, Weeks, Seasonal, Other)

• Abundance

• Maximum dissolved surface concentration:
Hi g h ( ≥ 1 m g /l ) , Medium ( ≥ 0.1, <1 m g /l ) , Low ( ≥ 0, < 0.1 m g /l )

High ( ≥ 0.1 mg/l), Medium ( ≥ 0.01, <0.1 mg/l), Low ( ≥ 0, < 0.01 m g /l )

• Dissolved oxyg en condition

( Surface, Bottom, Throu g hout water column ) ( Hi g h, Medium, Low, Not a factor) • Stratification (degree of influence): • Water column depth:

• Dominant p rimary p roducer: Pelagic, Benthic, Other • Tem p oral shift

• Dominant taxonomic g rou p ( number of cells ) :

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

Crustaceans, Molluscs, Annelids, Diverse mixture, Other • Tem p oral shift

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

PHOSPHORUS • Maximum dissolved surface concentration: • S p atial covera g e 1 , Months of occurrence • Limitin g factors

• Contributin g factors 5

• Concentrations 3,4
• Contributin g factors 5

• Event duration 3,4

• Fre q uencyof occurrence 3,4
• Contributin g factors 5

• Abundance 3,4
• Contributin g factors 5

• Concentrations 3,4

• Contributin g factors 5

• Concentrations 3,4
• Contributin g factors 5

• Min. avg. monthly bottom dissolved oxygen conc.3,4

• Fre q uencyof occurrence 3,4

• Event duration 3,4
• S p atial covera g e 3,4
• Contributin g factors 5

• Contributin g factors 5

• Contributing factors 5

• Contributin g factors 5

• S p atial covera g e 3,4
• Contributin g factors 5

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 continuall ythrou g hout the y ear) ( 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 • S p atial covera g e 1 , Months of occurrence, Fre q uencyof occurrence 2

• Months of occurrence, Fre q uencyof occurrence 2

• Months of occurrence, Fre q uencyof occurrence 2

• S p atial covera g e 1 , Months of occurrence

• S p atial covera g e 1 , Months of occurrence, Fre q uencyof occurrence 2

• S p atial covera g e 1 ( maximum values observed over a typ ical annual cy cle ) ( 1970 - 1995 )

(no trends information collected)

Problem (significant impact upon biological resources) No Problem (no significant impact)

Observed No OccurrenceALGAL CONDITIONSNUTRIENTSDISSOLVED OXYGENECOSYSTEM / COMMUNITY RESPONSE Problem (significant impact upon biological resources) No Problem ( no si g nificant im p act )

### 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 collectinformation 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, includingsite visits with selected experts to fill data gaps, regional assessment workshops to finalize and reach consensus on the responses to each question, andregional reports on the results. Estuaries were targeted for site visits based upon the completenessof 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 extensiveknowledge and insight about an estuary). In general, these persons had either filled out a surveyform and/or participated in a site visit. Preparations included sending all regional data to participants prior to workshops. Participants werealso 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 ofinformation sources from statistically tested monitoring data to general observations. Following the workshops, results were summarized for review by workshop participants. The information was thencompiled 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 parametersthat are related to nutrient enrichment. These parameters, in various combinations and at specific levels, are reflections of eutrophic conditions. Foreach of these parameters, information on characteristics of timing, duration, spatial coverage, andfrequency 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. Datagaps 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 werebased on either very limited data or general observations. The extent of data gaps and speculative responses is important because formulations developedto assess the rating of eutrophication status on a national basis use combinations of the parameters andparameter characteristics. The power of these formulations to accurately discriminate among systems isreduced 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 therewas 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 Reliability Spatial Coverage Reliability Frequency Reliability Sum of DCR Area Survey res p onse 3 Low Highly certain Not eval. Not eval. Not eval. Not eval. -- DCR value 3 1 1 1 1 1 1 3 Survey res p onse 28.8 Medium Highly certain High Spec-ulative Periodic Highly certain -- DCR value 28.8 1 1 1 0 1 1 0 Survey res p onse 18.1 Unknown Unknown Unknown Unknown Unknown Unknown -- DCR value 18.1 0 0 0 0 0 0 0 49.9 -- -- -- -- -- -- 3 System Total Tidal Fresh

Mixing

Seawater Salinity Zone



### Note that the speculativereliability rating for the spatial coverage call in the mixing zone and the unknown call for chlorophyll aconcentration 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 afor 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 AssessmentIn 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 datafor 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 ofeutrophic 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 testseveral analytical and numerical methods. Ultimately, a single model was developed that made maximum use of the survey data and best describedthe 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 aas an indicator), epiphyte abundance, and macroalgaerepresent the first possible stage of water quality degradation associated with eutrophication. Althoughnitrogen 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 ConditionA 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 ofthe 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 takingan 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 overallcategories 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

Episodic High Episodic Moderate 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

Episodic High
Episodic Mod/Low/Very Low 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 Episodic Low/Very Low Low 0.25

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 AND AND IF

Periodic

Periodic

Periodic Any Spatial Coverage

Any Spatial Coverage 

### Phase 1: Primary Symptoms Method Description. This method assesses the level of expression of chlorophyll
aconcentrations, epiphyte abundance problems, and macroalgal abundance problems. The method uses onlythe 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

AND IF THEN 

### 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 AND IF 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 A z = surface area of a single zone
A t = 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

Episodic High Episodic Moderate/Low/Very Low 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
Episodic High
Episodic Moderate/Low/Very Low 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 AND AND IF 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 AND IF THEN

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 Frequency Nuisance Blooms

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
Frequency Toxic Blooms

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 AND IF THEN AND

### Appendix A: Methods

58 Phase 3: Determination of the OverallLevel 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 assessmentsbased 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 reviewedeach primary and secondary symptom assessment for all 138 estuaries in the survey. In some cases changes were made to theseassessments based on the experts knowledge of the estuary. For instance, borderline estuaries with values around 0.3 and 0.6were 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 1Low Primary Symptoms Moderate Primary SymptomsHigh Primary Symptoms

0.3 0.6 1 n= total number of zones in estuary A z = surface area of a single zone
A t = 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 aquaticvegetation 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. Forblooms 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 / VOL estuary



### 1 / VOL estuary



### 1 / VOL fwf 

### 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 ofnutrient 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 largepart 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 partof 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) 31 LOW and
and
and
and
and
and
and
and (10 00to 10 -02 ) macro (>6) small (10 -03, 10 -04 ) MODERATE (10 00, 10 -01 ) moderate (10 -02 ) (10 -03, 10 -04 ) (10 00, 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) ofthe 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

60Combining 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 highEXP 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 flushnutrients, 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 PopulationCensus, 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 pressurewith respect to the observed eutrophic symptoms. Estimates of total nitrogen loads are provided for five major nutrient source types: pointsources, fertilizer, livestock, atmospheric deposition, and nonpoint/nonagricultural. Data areavailable 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, NOAAaggregated 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 andthe 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 InputHigh SusceptibilityModerate SusceptibilityLow 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

MODERATE LOW LOW LOW OVERALL LEVEL OF HUMAN INFLUENCEHighModerateLow 

### High Moderate Low DILUTION PotentialFLUSHING 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 OutlookThis analysis was performed as an attempt to determine the likelihood of whether conditions in an estuary will worsen, improve, or stay the sameover the next twenty years. In the analysis, nutrient input changes are predicted to determinewhich 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 offuture nutrient input changes. However, population projections are subject to unpredictablechanges. Therefore, experts at the National Assessment Workshop were asked to make modifications to the determinations of future nutrient changes, based on their knowledge of plannedor 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 ConcernsExperts at the National Assessment Workshop identified impaired uses which they judged to be relatedto 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 andhabitat 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 andnonpoint sources which they judged as most important to target for managing nutrients. These sources included wastewater treatment, combined seweroverflow, on-site waste disposal such as septic systems, industrial discharge, large animal operations,urban runoff, agriculture, forestry practices, rangeland use, atmospheric inputs, and aquaculture. Alsoevaluated 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 NeedsExperts 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

Chlorophyll a 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

64 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

Chlorophyll a 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 - estu

arine 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

Chlorophyll a 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 - estu

arine 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

66 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

Chlorophyll a 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 - estu

arine 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 partici pant filled out all or part of an initial data collection form for one or more estuaries. The regional assessment column indicates that theparticipant 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 M aine Maritime Academy √ √ Laurice Churchill Maine Dept. of Marine Resources √ Philip Colarusso U.S. Environmenal Protection Agency √ Canthy Coniaris University of New Hampshire Michael Connor M assachusetts Water Resources Auth. √ Jerome Cura M enzie-Cura & Associates Inc. √ √ Lee Doggett Maine Dept. of Environmental Protection √ √ William Ellis Maine Maritime Academy √ Bernie Gardner University of M assachusetts √ √ Hap Garritt Woods Hole Oceanographic Institute √ Chris Garside Bigelow Laboratory for Ocean Sciences √ √ Diane Gould M assachusetts Bay Program √ √ Chris Heinig Inte rtide 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 Darli ng 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 M assachusetts 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 M aryland 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 Inte rstate 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 Sali sbury State University √ Stephen Jordan Maryland Dept. of Natural Resources √ Renee Khan Ma ryland 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 Maryl and - 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 Coll ege 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 Fi sheries √ 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 Ca lifornia St. University at Long Beach √ √ Randall Brown C alifornia 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 El khorn 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 Or egon 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 Cali fornia 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 Ca lifornia 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 M etropolitan King County √ √ Mark Silberstien Elkhorn Slough Nat. Est. Research Reserve √ Lawrence Small O regon 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 B attelle/Marine Sciences Laboratory √√ √ Bruce Thompson San Francisco Estuary Institute √ Ken Thompson Irvine Ranch Water District √ Tim Unterwegner Or egon 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. En vironmental 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 √√√√