IN THE COASTAL WATERSHEDS OF THE CONTERMINOUS UNITED STATES

2004 to 2009

Status and Trends of Wetlands
U.S. Department of the Interior

Fish and Wildlife Service

and

National Oceanic and Atmospheric 

Administration

National Marine Fisheries Service
Status and Trends of Wetlands

IN THE COASTAL WATERSHEDS OF THE CONTERMINOUS UNITED STATES

2004 to 2009
Status and Trends of Wetlands

in the Coastal Watersheds of the 

Conterminous United States

2004 to 2009

Thomas E. Dahl

U.S. Fish and Wildlife Service

and

Susan-Marie Stedman

NOAA, National Marine Fisheries Service
iii

Acknowledgments

The authors would like to recognize key individuals from their respective agencies 

who have supported the completion and review of this study. Specifically, from the 

U.S. Fish and Wildlife Service, Gary Frazer, Assistant Director, Ecological Services; 

Paul Souza, Deputy Assistant Director, Ecological Services; Martha Balis-Larson, 

Chief, Division of Budget and Technical Support; Jonathan Phinney, Chief, Branch 

of Geospatial Mapping and Technical Support. From the National Oceanic and 

Atmospheric Administration’s National Marine Fisheries Service; Tom Bigford, Chief, 

Habitat Protection Division, Office of Habitat Conservation; and Buck Sutter, Director, 

Office of Habitat Conservation.

Peer review of the study findings and report was provided by the following subject matter experts: Jim Dick, U.S. Fish and Wildlife Service, Regional Wetlands Coordinator, 

Albuquerque, NM; Mark Gernes, Research Scientist, Minnesota Pollution Control Agency, 

St. Paul, MN; Virginia Hansen, U.S. Environmental Protection Agency, Gulf Ecology 

Division, Gulf Breeze, FL; Dr. Mary Kentula, U.S. Environmental Protection Agency, 

National Health and Environmental Effects Research Laboratory, Western Ecology 

Division, Corvallis, OR; William Kirchner, U.S. Fish and Wildlife Service, Regional 

Wetlands Coordinator, Portland, OR; Emily Sheehan, ORISE Fellow, U.S. Environmental 

Protection Agency, Office of Wetlands, Oceans and Watersheds, Wetlands Division, 

Washington, D.C. 

A Technical Review Team from the U.S. Fish and Wildlife Service was responsible for 

ensuring the validity of standard operating procedures, technical protocols, project 

documentation and quality assurance. Key personnel from the National Standards 

and Support Team in Madison, WI contributed considerable efforts to this project 

including Mitchell T. Bergeson, Geographic Information Systems Specialist; Andrew Cruz, 

Information Technology Specialist; Jane Harner, Geographic Information Analyst, 

Rusty K. Griffin, Physical Scientist and Sydney Nick, Geospatial Analyst.

Myra Price, U.S. Environmental Protection Agency, Office of Wetlands, Oceans and 

Watersheds, Wetlands Division, Washington, D.C. assisted in field verification work in 

both the Gulf of Mexico and the Pacific coastal regions. Technical review and editorial 

assistance was provided by Dr. Bill Wilen and Jo Ann Mills, U.S. Fish and Wildlife 

Service, Headquarters, Arlington, VA. 

Partial funding for this study was provided by the U.S. Environmental Protection Agency, 

Office of Wetlands, Oceans and Watersheds, Wetlands Division.

This report should be cited as:

T.E. Dahl and S.M. Stedman. 2013. Status and trends of wetlands in the coastal watersheds

of the Conterminous United States 2004 to 2009. U.S. Department of the Interior, Fish and Wildlife Service 

and National Oceanic and Atmospheric Administration, National Marine Fisheries Service. (46 p.)
Conversion Table

U.S. Customary to Metric

inches (in.) x 25.40 = millimeters (mm)

inches (in.) x 2.54 = centimeters (cm)

feet (ft) x 0.30 = meters (m)

miles (mi) x 1.61 = kilometers (km)

square feet (ft2) x 0.09 = square meters (m2)

square miles (mi2) x 2.59 = square kilometers (km2)

acres (A) x 0.40 = hectares (ha)

Farenheit degrees (FE) 0.5556 (FE-32) = Celsius degrees (CE)

Metric to U.S. Customary

millimeters (mm) x 0.04 = = inches (in.)

centimeters (cm) x 0.39 = inches (in.)

meters (m) x 3.28 = feet (ft)

kilometers (km) x 0.62 = miles (mi)

square meters (m2) x 10.76 = square feet (ft2)

square kilometers (km2) x 0.39 = square miles (mi2)

hectares (ha) x 2.47 = acres (A)

Celsius degrees (CE) 1.8(CE) + 32 = Fahrenheit degrees (FE)

General Disclaimer

The use of trade, product, industry, or firm names or products in this report is for informative 

purposes only and does not constitute an endorsement by any agency of the U.S. Government.

iv
v

Table of Contents

Executive Summary .........................................................................................................1

Introduction.....................................................................................................................4 

Coastal Wetlands.............................................................................................................6 

Study Area.....................................................................................................................10

Study Methods...............................................................................................................12

Habitat Definitions........................................................................................................13 

Study Limitations...........................................................................................................14

Results: Status of Wetlands in Coastal Watersheds, 2009...............................................16 

Changes in Wetlands of the Coastal Watersheds, 2004 to 2009.....................................20

Trends in Saltwater Wetlands, 2004 to 2009 .................................................................22

Trends in Coastal Freshwater Wetlands, 2004 to 2009 ..................................................26

Discussion.....................................................................................................................32

Summary ......................................................................................................................38

References Cited............................................................................................................40 

Appendix: Definitions of Habitat Categories..................................................................43 
vi

List of Figures

Figure 1. Aerial view of saltwater (intertidal) wetlands that include emergent 

salt marsh and non-vegetated shoals and sandbars ...............................................5

Figure 2. Coastal mangroves colonize intertidal areas along the coast of the 

southern United States..........................................................................................7

Figure 3. Saltwater marshes of a coastal watershed along the Gulf Coast of Louisiana .....7

Figure 4. Freshwater wetlands of a coastal watershed in Alabama ...................................7

Figure 5. Storm damage and saltwater inundation resulting from Hurricane Irene

 along the coast of North Carolina in 2011 ...........................................................8 

Figure 6. Tidal waters flood a city street in Key West, Florida ..........................................8

Figure 7. Changes in population density in the United States from 1980 to 2008 ............9

Figure 8. Coastal Watersheds of the Conterminous United States 

as used in this study............................................................................................11

Figure 9. Freshwater and saltwater wetland by area in the coastal watersheds, 2009.....16

Figure 10. Percent of all coastal wetland area by coastal region, 2009 ..........................17

Figure 11. Relative wetland density of the coastal watersheds along the Atlantic,

Gulf of Mexico, Great Lakes and Pacific as determined by this study, 2009........17

Figure 12. Saltwater (intertidal) wetland distribution (area in acres) by coastal 

regions, 2009......................................................................................................19

Figure 13. Rocky shoreline along the coast of California................................................19

Figure 14. Freshwater wetland distribution (area in acres) by coastal regions, 2009.......19

Figure 15. Wetland gains and losses in the coastal watersheds of each 

coastal region between 2004 and 2009 ..............................................................20

Figure 16. Attribution of loss or conversion of saltwater wetlands in the coastal 

watersheds of the Atlantic, Gulf of Mexico and Pacific, 2004 to 2009 ................22

Figure 17. Coastal watersheds of the upper Gulf of Mexico showing the magnitude

 of intertidal (saltwater) wetland loss to open water, 2004 to 2009......................23

Figure 18. Tidal saltmarsh in coastal Washington ..........................................................25

Figure 19. Estimated losses and gains in area for the freshwater wetland 

types in the coastal watersheds, 2004 to 2009....................................................26

Figure 20. Forested wetland losses in the coastal watersheds of the 

Southeastern U.S. (North Carolina to Texas) as attributed to upland 

land use categories, 2004 to 2009 ......................................................................27

Figure 21. This aerial image shows the proliferation of freshwater ponds in a 

south Florida coastal watershed overtaken by development................................30

Figure 22. Attribution of loss or conversion of freshwater wetlands in the 

coastal watersheds, 2004 to 2009.......................................................................31

Figure 23. The term “Other” lands has been used to describe land in transition 

when it was not possible to categorize a distinguishable land use 

(i.e. urban or agriculture) ....................................................................................33 

Figure 24. A residential housing development built on filled wetland in the upper 

portion of a coastal watershed in Louisiana ........................................................35
vii

List of Tables

Table 1. Area (in acres) of coastal watersheds and shoreline (in miles) 

included in this study..........................................................................................10

Table 2. Wetland, deepwater and upland categories used to conduct this study............14

Table 3. Estimated freshwater wetland area in the coastal watersheds 

of the Atlantic, Gulf of Mexico, Great Lakes and Pacific as 

compared to the conterminous United States, 2009............................................18

Table 4. Changes in wetland area for the coastal watersheds of the

Atlantic, Gulf of Mexico, Great Lakes and Pacific, 2004 to 2009........................21

Table 5. Estimated status and change in wetland area for selected 

categories in the coastal watersheds of the Atlantic, 

Gulf of Mexico, Great Lakes and Pacific, 2004 to 2009......................................21

Table 6. Estimated changes to saltwater (intertidal) wetlands of the Atlantic, 

Gulf of Mexico and Pacific coastal watersheds, 2004 to 2009 ............................24

Table 7. Estimated changes to freshwater wetlands of the Atlantic, 

Gulf of Mexico, Great Lakes and Pacific, 2004 to 2009......................................28

Executive Summary

Coastal wetlands in the United States are diverse and 

include both saltwater wetlands that occur along the 

coastal shorelines and freshwater wetlands that extend 

inland within the coastal drainages. Influenced by water 

that connects the upper reaches of the watershed with 

the oceans or Great Lakes, these wetlands play a pivotal 

role in the watershed. Wetlands in coastal watersheds 

provide crucial habitat for wildlife by providing 

spawning grounds, nurseries, shelter, and food for finfish, 

shellfish, birds and other wildlife. These wetlands also 

help improve water quality by filtering and detoxifying 

runoff from residential, agricultural, and urban areas. 

Furthermore, there is an increasing awareness of the 

important role these coastal wetlands play in buffering 

coastlines against storm and wave damage and in 

stabilizing shorelines in the face of climate change 

impacts. 

In 2008, the U.S. Fish and Wildlife Service (USFWS) in 

coordination with the National Oceanic and Atmospheric 

Administration (NOAA) released a report documenting 

wetland trends in the coastal watersheds of the Atlantic, 

Gulf of Mexico and Great Lakes (Stedman and Dahl 

2008). That study did not include the wetlands in the 

coastal watersheds along the Pacific coast. Findings 

from that study indicated that there was a net loss of 

an estimated 361,000 acres of wetland in the coastal 

watersheds of the eastern U.S. between 1998 and 2004. 

There was considerable variation in trends among the 

three coastal regions studied. Watersheds of the Great 

Lakes experienced net gains in wetlands, whereas 

watersheds along the Atlantic and Gulf of Mexico 

coasts experienced an overall net loss of an estimated 

60,180 acres annually. Attribution of these losses 

pointed to development and other human activities as 

the principle cause of loss in the Gulf of Mexico and salt 

water intrusion or inundation as the primary cause of the 

losses observed in the mid-Atlantic region. The release of 

that information stimulated discussion at the Federal level 

centering on the need for increased wetland protection 

and restoration measures in the coastal watersheds 

and the role of federal, state or local mechanisms in 

protecting these coastal resources. 

Working in conjunction with principal Federal agencies 

the USFWS and NOAA have produced updated data on 

more recent trends of wetlands in the coastal watersheds 

to help prioritize conservation planning efforts and 

contribute additional information on coastal wetland 

trends. 

This report updates and expands previous information on 

coastal wetland loss by incorporating new data for the 

coastal watersheds of the Atlantic, Gulf of Mexico and 

Great Lakes and in addition, providing information for 

the Pacific coast along the States of Washington, Oregon 

and California. It presents the latest status information 

on coastal wetland resources and provides estimates of 

losses or gains that occurred in the coastal watersheds 

in the conterminous U.S. between 2004 and 2009. The 

information presented provides data on the areal extent of 

wetlands but does not assess wetland condition or other 

qualitative changes to wetlands in coastal watersheds.

Suisun Marsh, California 
2 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

To estimate wetland extent and change, this study 

used randomly selected 4.0 square mile (2,560 acres 

or 1,036 ha) sample plots and digital high-resolution 

imagery to identify change in wetlands, deepwater 

habitats and uplands. A total of 2,614 plots were used to 

sample the coastal watersheds and ground verification 

was done for 380 plots (14.5 percent). Wetlands and 

deepwater habitats were described using the USFWS 

biological definition of wetland (Cowardin et al. 1979) 

and followed the procedural, quality control and analysis 

protocols as have been developed for the National 

Wetlands Status and Trends reporting conducted by 

USFWS.

In 2009, there were an estimated 41.1 million acres of 

wetlands in the coastal watersheds of the United States. 

This area represented 37.3 percent of total wetland 

area in the conterminous U.S. Of the wetland area in 

the coastal watersheds, an estimated 34.6 million acres 

(84.3 percent) were freshwater wetlands and 6.4 million 

acres (15.7 percent) were saltwater wetlands. Between 

2004 and 2009, wetland area in the coastal watersheds 

of the U.S. declined by an estimated 360,720 acres. The 

average annual rate of change was an estimated loss of 

80,160 acres, a 25 percent increase in the rate of wetland 

loss from the previous reporting period1

. The increase in 

the rate of coastal wetland loss was statistically significant 

(p = 0.007) when results from this study were compared 

to the coastal wetland loss estimates from the 1998 to 

2004 study as reported by Stedman and Dahl (2008).

The watersheds of the Atlantic and Gulf of Mexico had 

very similar amounts of wetland area (15.9 million and 

15.4 million acres, respectively) in 2009. Watersheds 

of the Great Lakes had an estimated 8.5 million 

acres of wetland. The Pacific coastal watersheds had 

the least amount of wetland area with an estimated 

1.3 million acres. The Atlantic, Gulf of Mexico, and 

Pacific coastal regions experienced net wetland losses 

between 2004 and 2009 of 111,960 acres, 257,150 acres 

and 5,220 acres, respectively. The watersheds of the 

Great Lakes region experienced a net gain in wetland 

area of an estimated 13,610 acres. Seventy one percent 

of the estimated wetland losses were in the coastal 

watersheds of the Gulf of Mexico. 

1

The average annual rate of loss for the six years between 1998 and 

2004 was 59,000 acres compared to the average annual rate of loss for 

the 4.5 years between 2004 and 2009 being 80,160 acres.

Saltwater wetlands sustained an estimated net loss of 

95,000 acres as modest gains in marine and estuarine 

non-vegetated wetlands (flats, shoals and bars) were 

overshadowed by losses of estuarine vegetated wetlands, 

which declined by 2.4 percent. Most of the vegetated 

estuarine losses were to open saltwater deepwater habitats, 

and virtually all of these losses occurred in the Gulf of 

Mexico. 

In the freshwater system, emergent marshes and shrub 

wetlands increased in area; however, freshwater forested 

wetlands declined by an estimated 405,700 acres resulting 

in a net loss of freshwater vegetated wetland area of 

328,800 acres (1.0 percent) between 2004 and 2009. 

Forested wetlands lost to uplands in silviculture accounted 

for an estimated 179,080 acres or 65 percent of the 

freshwater wetland losses to upland land uses. Regionally, 

the Pacific coast sustained a small net loss (5,180 acres) of 

freshwater wetlands, while the Atlantic experienced larger 

net losses of 112,290 acres, the Gulf of Mexico sustained 

net losses of 161,870, and the Great Lakes saw a modest 

net gain of 13,610 acres in their coastal watersheds. 

The area of freshwater ponds increased by almost 

six percent, although many were located in urban or 

suburban developments as likely water detention ponds 

or ornamental ponds as opposed to targeted wetland 

reestablishment projects. The vast majority of these new 

ponds (99 percent) were constructed in the watersheds of 

the Atlantic and Gulf of Mexico. 

Although both saltwater and freshwater wetlands sustained 

net losses between 2004 and 2009, some coastal wetland 

gains occurred through reestablishment projects. These 

were most prevalent on agricultural lands primarily in the 

coastal watersheds of the Great Lakes, South Carolina, 

Georgia, and the upper reaches of the watersheds in 

central Florida. In general, wetland reestablishment in 

coastal watersheds has lagged behind reestablishment rates 

observed nationally for a variety of reasons. A strategy 

of achieving “no net loss” by offsetting wetland acreage 

losses with wetland creation or reestablishment does not 

appear to be effective in the coastal watersheds as wetland 

losses have increased in some coastal regions. Continuing 

losses of wetlands in coastal watersheds have direct costs 

for people and longer-term resource implications for fish, 

wildlife and other natural resources.
Executive Summary  ﻿﻿ 3

Black Skimmers (Rynchops niger), Laughing Gulls (Leucophaeus atricilla), Sandwich Terns (Thalasseus sandvicensis), Gulf coast 

of Florida 

This report is the result of a cooperative effort between the U.S. Department of the Interior’s Fish and 

Wildlife Service and the National Oceanic and Atmospheric Administration’s National Marine Fisheries 

Service. Continuing efforts to monitor coastal wetland status and trends described in this report have 

been supported by the Federal Interagency Coastal Wetlands Workgroup – a multi-agency group 

comprised of members from the Environmental Protection Agency, NOAA, USFWS, U.S. Army Corps 

of Engineers, Natural Resources Conservation Service, the Federal Highway Administration and the 

U.S. Geological Survey. 
4 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Introduction

Coastal wetland ecosystems include not only the 

wetlands adjacent to the ocean coast or Great Lakes 

but also those within the coastal watershed boundary 

(NOAA 2012). Thus coastal wetlands included in the 

study can be described as all wetlands in each 8-digit 

hydrologic unit code2 watershed that drains directly to 

the ocean coast and contain a tidal waterbody, as well 

as watersheds that drain directly to one of the Great 

Lakes. Both saltwater and freshwater wetlands are 

included within this watershed-based ecosystem concept. 

Mangrove forests, fresh and saltwater marshes (Figure 1), 

forested and shrub wetlands, coastal shoals, tidal mud 

flats, sand spits (bars), beaches, tidal pools and freshwater 

ponds occur in coastal wetland ecosystems. 

The Federal Government, working closely with 

States, other partner organizations, and the public 

has a crucial role to play in identifying stressors 

facing coastal environments and in developing and 

implementing actions that ensure the continued health 

and availability of our Nation’s ocean, coastal, and Great 

Lakes resources. The U.S. Fish and Wildlife Service 

(USFWS) and the National Oceanic and Atmospheric 

Administration’s National Marine Fisheries Service 

(NOAA Fisheries) have collaborated in a number of 

efforts to produce information on coastal wetland habitats 

as they influence fish and wildlife species distribution, 

enhance the physical or ecological condition of coastal 

areas (e.g. storm surge protection and water quality 

improvement) and provide socioeconomic benefits to 

many Americans. 

In 2008, USFWS in conjunction with NOAA released 

a report documenting wetland trends in the coastal 

watersheds of the Atlantic, Gulf of Mexico and Great 

Lakes (Stedman and Dahl 2008). The findings from 

that study indicated that an estimated 38 percent of all 

wetland acreage in the conterminous United States was 

found in these coastal watersheds. Coastal watersheds 

had sustained an estimated 361,000 acres of wetland 

loss between 1998 and 2004 or an average of nearly 

60,000 acres each year. The loss of these coastal habitats 

diminished the health of these ecosystems and reduced 

their ability to provide environmental and socioeconomic 

services (Wolanski et al. 2009). The release of that report 

stimulated discussion at the Federal level centering on 

increased wetland protection and restoration measures in 

the coastal watersheds. Monitoring of coastal indicators 

including wetland loss has shown that coastal planning 

and management policies over the past 30 years have 

limited, but not curtailed, harmful cumulative impacts 

on coastal ecosystems (USEPA 2012). As a result, there 

is continuing interest in the effectiveness as well as the 

limitations of federal, state or local mechanisms to protect 

these coastal resources. 

In response to concerns about the rate of wetlands loss in 

coastal watersheds, the Environmental Protection Agency 

(EPA) has been leading an interagency effort to examine 

wetland losses in coastal watersheds and identify stressors, 

strategies, policies and information to protect and restore 

coastal wetland resources. This interagency effort has 

a goal to raise awareness of coastal wetland functions, 

threats and conservation opportunities to reverse losses of 

wetlands in coastal watersheds. The Interagency Coastal 

Wetlands Workgroup (ICWWG) established by EPA also 

includes NOAA, USFWS, U.S. Army Corps of Engineers, 

Natural Resources Conservation Service, Federal Highway 

Administration and the U.S. Geological Survey. With the 

support of the ICWWG, EPA and NOAA held a series 

of seven workshops in coastal watersheds3

, soliciting 

information and views from those most familiar with 

wetland issues in those watersheds regarding wetland 

stressors, effective tools and strategies for reducing wetland 

loss in coastal watersheds. The results of those workshops 

have been published in a set of regional reports available 

on the EPA and NOAA web sites (USEPA 2013a; 2013b).

At roughly the same time, USFWS embarked on a national 

update of the National Wetlands Status and Trends 

Study for the time period from 2004 to 2009. Working 

in conjunction with principal Federal agencies,4

 that 

study formed the basis for this update on the status and 

2 Drainage basins in the United States have been divided and subdivided at four different levels and each assigned a unique hydrologic 

unit code consisting of eight digits based on these four levels.

3 Workshops were conducted in the following watersheds: Cape Cod, 

Delaware Estuary, York River (VA), Lower and Middle Neuse River (NC), 

Indian River (FL), Mississippi Coastal, and Galveston Bay.

4

 Funding or technical assistance for the National Wetlands Status and 

Trends study was provided by the Environmental Protection Agency, 

Department of Agriculture (Natural Resource Conservation Service), 

Department of the Army (Army Corps of Engineers), National Oceanic and 

Atmospheric Administration (National Marine Fisheries Service) and the 

Department of the Interior (Fish and Wildlife Service). Additional support 

for work in the coastal watersheds was provided by EPA and NOAA.
more recent trends of wetlands in coastal watersheds. 

This report expands the information for the coastal 

watersheds of the conterminous U.S. by updating data 

for the coastal watersheds of the Atlantic, Gulf of Mexico 

and Great Lakes, which were included in the previous 

coastal watersheds report, and adding information for the 

Pacific Coast along the States of Washington, Oregon and 

California. 

This report presents the latest status information on 

coastal wetland resources and provides estimates of 

losses or gains5

 that occurred in the coastal watersheds 

in the conterminous U.S. between 2004 and 2009. 

The information presented provides data on the 

areal extent of wetland types, both past and present, 

to help prioritize conservation planning efforts for 

coastal wetland resources and contribute additional 

information to the ICWWG to facilitate strategy and 

policy development. Additional wetland impacts 

have occurred in non-coastal watersheds which 

cumulatively drain to coastal waters and thus have an 

additive influence on coastal ecosystems (Dahl 2011). 

This increases the importance of coastal wetlands 

in ecosystem interchange and function. This study 

does not assess wetland condition or other qualitative 

changes to wetlands in coastal watersheds. Readers 

are referred to the National Coastal Condition Report 

IV (USEPA 2011) for information on the qualitative 

aspects of coastal resources.

5

 Wetland loss or gain as used in this report is defined as a decline or 

increase in wetland area.

Introduction 5

Figure 1. Aerial view of saltwater (intertidal) wetlands that include emergent salt marsh and non-vegetated shoals 

and sandbars (foreground). Atlantic coastline of Virginia, 2008.
6 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Coastal Wetlands 

Wetlands in coastal watersheds are part of a diverse and 

complex set of ecosystems that are vital to the Nation’s 

economy and an important part of our natural heritage. 

Centuries ago, coastal wetlands and estuaries provided 

the fish, waterfowl and building materials that supported 

native populations and European settlers. That vital role 

continues today, with more than half of the fish caught 

for recreational or commercial purposes in the U.S. 

depending on estuaries and their coastal wetlands at 

some point in their life cycles (Lellis-Dibble et al. 2008). 

Other wetlands in the coastal watersheds provide 

nurseries, shelter and food for finfish (Figure 2), shellfish, 

shorebirds and marine mammals (Twilley et al. 1996; 

Spalding et al. 2010). Coastal wetlands also provide 

resting, feeding and breeding habitat for 75 percent of 

the Nation’s waterfowl and other migratory birds (USEPA 

2005; 2012). Healthy coastal wetlands are among the 

most productive ecosystems on the planet, comparable 

to rainforests and coral reefs. That productivity is 

particularly important to the nearly 45 percent of the 

Nation’s endangered and threatened species that depend 

on wetland habitats (USFWS 1995). 

In addition to providing habitat for fish and wildlife, 

wetlands in the coastal watersheds benefit humans 

by improving water quality (through the filtering and 

detoxifying of runoff), protecting coastal communities 

against damage from erosion and flooding, and providing 

recreational opportunities for wildlife viewing and 

exploration, hunting, fishing and tourism. The overall 

level of economic activity generated in all coastal 

counties in the U.S. is over $6.6 trillion or just under half 

of the Nation’s gross domestic product in 2011 (NOAA 

2012). Because they provide such crucial services it is 

in our national interest to responsibly use, conserve and 

protect these coastal resources.

Coastal wetland types are diverse and include salt 

marshes (Figure 3), mangrove swamps, freshwater 

forested swamps (Figure 4), flat-woods, freshwater 

marshes, shrub depressions and wetlands adjacent to 

tidal rivers. The definitive factor in describing coastal 

wetlands is the tidal influence and hydrologic connection 

of the watershed with the ocean (or the Great Lakes). 

For this reason, coastal wetlands can be described as all 

wetlands in watersheds that drain to the Atlantic Ocean, 

Gulf of Mexico or Pacific Ocean, and contain a tidal 

waterbody; as well as wetlands that drain directly to 

one of the Great Lakes.6

 All wetlands in these coastal 

watersheds formed the target population included in 

this study.7 This landscape-level or ecosystem-based 

approach encompasses concepts fundamental to working 

toward integrated, comprehensive policy development, 

management and conservation of our coastal resources.

The distribution and condition of wetlands in coastal 

watersheds are strongly influenced by natural processes. 

Both man-made and natural stressors influence wetland 

abundance, type, distribution and vulnerability to 

changes. Saltwater wetlands are found at the interface of 

land and sea where they form linkages between inland 

landscapes and the ocean. These intertidal wetlands 

experience oceanic influences in areas of high energy 

where tides, winds, waves and currents alter shorelines 

and inundate coastal landscapes (Figures 5 and 6). 

Wetlands along this interface are subject to erosion, 

saltwater inundation, salinity changes, land subsidence 

and changes in sediment deposition patterns. Coastal 

wetlands in the upper parts of a watershed are subject 

to less erosion, but may still be affected by the other 

factors mentioned. In some situations coastal wetlands 

can adapt to these changes in a number of ways, such as 

moving inland with rising sea level, changing vegetation 

composition or distribution in response to salinity 

changes, or colonizing new areas when spits or barrier 

islands change location. However, human impacts on the 

landscape can impede the ability of coastal wetlands to 

adapt to their dynamic environment.

6

 NOAA has used a specific methodology to identify coastal watersheds using hydrologic unit boundaries that contain tidal water bodies. 

This excludes several areas that actually drain to one of the coastlines 

(i.e. surrounded by coastal watersheds) but do not contain tidal water 

bodies. There may also be limitations due to the precision of watershed 

boundary demarcation. 

7 The Pacific coast included watersheds in Washington, Oregon and 

California.
Figure 3. Intertidal (saltwater) marshes of a coastal 

watershed along the Gulf of Mexico, Louisiana.

Figure 4. Freshwater wetlands of 

a coastal watershed, Alabama.

Coastal Wetlands 7

Figure 2. Mangroves colonize 

intertidal areas along the coast of the 

southern United States. 
Figure 5. Storm damage and saltwater inundation resulting 

from Hurricane Irene along the coast of North Carolina, 2011.8

In addition to the property damage and threats to coastal 

residents, the frequency and intensity of coastal storms can 

also influence coastal wetland types and distribution through 

erosion, deposition of sediments or by increasing salinity.

8

 The impacts of Hurricane Irene (2011) or Hurricane Sandy (2012) 

were not included in this study timeframe.

8 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Figure 6. Tidal waters flood a city street in Key West, Florida. 

Rising sea levels, saltwater inundation or coastal storms are a 

concern along certain coastlines. 
Losses and degradation of wetlands in coastal watersheds 

can be directly traced to population pressures and 

conversion of wetlands to developed or agricultural uses, 

with resulting changes in water flow, increased pollution 

and habitat fragmentation (Stedman and Dahl 2008). 

As human habitation in coastal areas has increased, 

population density in the coastal counties has risen to 

be far greater than that of non-coastal counties (Crossett 

et al. 2004). For example, in coastal North Carolina, 

the lands situated between the ocean and the interior 

have exhibited consistently higher growth of residential 

development than lands far from the coast (Crawford 

2007), and that same trend can be seen elsewhere in 

many coastal states. However, census data understate the 

impacts of development in many coastal areas because 

they do not account for seasonal influxes of residents 

and the related infrastructure needed to support coastal 

oriented tourism and growth (Beach 2002). Coastal 

development often contributes to land use changes that 

increase impervious surface area, affect water quality 

or disturb natural habitats through loss or fragmentation 

(Crawford 2007). The effects of development on 

wetlands are important as some estimates indicate that 

development will cover one quarter of the land area of 

the Nation’s coastal watersheds by 2015 (Beach 2002). 

Figure 7 shows the increase in population in coastal 

counties in the conterminous U.S. These increases in 

population density are frequently associated with greater 

demands for resources (USEPA 2013a) and wetlands in 

coastal watersheds are more likely to be lost or degraded 

when wetlands come into conflict with land development 

interests or other stressors associated with urbanization, 

infrastructure development, or land-use changes that alter 

hydrology (Dahl 2011). 

Non Coastal Counties

Coastal Counties

1970 1980 1990 2000 2010

Year

450

400

350

300

250

200

150

100

50

0

Persons per Square Mile

Coastal Wetlands 9

Figure 7. Changes in population density in the conterminous United States from 1970 to 2010. Data adapted from NOAA 

(2012). 
Study Area 

The study area was the coastal watersheds of the 

Atlantic, Great Lakes, Gulf of Mexico and Pacific coasts 

(Figure 8). NOAA uses a specific methodology (NOAA 

1999) to identify coastal watersheds by combining 

information on the extent of ocean-derived tidal 

influence and the mapping of watershed (drainage) 

boundaries. The 8-digit hydrologic unit watersheds 

that contained tidal water bodies were used to denote 

coastal watersheds for this study. A similar method was 

used in the Great Lakes region to identify the extent of 

non-tidal coastal watersheds of the Great Lakes.

The outer coastal boundary was determined by the 

extent of the coastal sampling frame used by the 

FWS’ National Wetlands Status and Trends Study 

for the Atlantic, Gulf of Mexico, Pacific and Great 

Lakes coastal areas. The total area sampled in these 

four coastal areas was 246.9 million acres9

 (Table 1). 

The inland study boundary coincided with the 

corresponding coastal watershed boundaries as 

provided by NOAA however, along the Pacific coast, 

this inland boundary was truncated by the Coast Range 

Physiographic Region boundary. The San Francisco Bay 

was also modified to include Sourin Bay. 

The Atlantic coastline extends approximately 

2,070 miles from Maine to south Florida. Coastal 

regions vary considerably from the steep rocky 

shorelines of New England to broad, flat coastal 

marshes in the Carolinas and the limestone landscapes 

of south Florida. Much of the Atlantic coast is typified 

by large coastal bays and sounds including Delaware 

Bay, Chesapeake Bay, Albemarle Sound, Pamlico 

Sound and the Indian River Lagoon. Barrier islands 

such as North Carolina’s Outer Banks provide physical 

barriers between waves and tidal energy of the ocean 

and mainland features. Tidal stages range between a few 

inches in the Carolinas to 7 to 13 feet in parts of New 

England (USEPA 2012). The negative effects of human 

habitation on coastal wetlands and other natural resources 

can be readily seen in the urban corridor that stretches 

from New York City to Washington D.C. (National Fish 

Habitat Board, 2010). The coastal counties along the 

Southeast Atlantic had the largest rate of population 

increase (79%) of any coastal region in the conterminous 

United States between 1980 and 2006.

The Gulf of Mexico has about 1,630 miles of shoreline 

extending from the subtropical reefs of the Dry Tortugas 

in Florida to the extensive coastal flats and marshes of the 

Texas coast. The Mississippi delta (including Barataria 

and Terrebonne Bays) and its associated habitats are a 

major feature of this coastal area, as are Tampa Bay, 

Mississippi Sound and Galveston Bay. Engle (2011) has 

summarized some of the ecosystem services provided by 

wetlands along the Gulf coast. The economic importance 

of the resources in the Gulf were recently underscored by 

the Deepwater Horizon oil spill in 2010,10 which affected 

hundreds of species of resident and migratory wildlife, 

commercial and recreational fishing, tourism and regional 

businesses of many types. A majority of the wetland loss 

(61,800 acres) found in coastal watersheds between 1998 

and 2004 occurred along the Gulf of Mexico. Some of that 

loss was associated with the long-term continuing erosion 

and subsidence of the Mississippi delta, but more was 

related to development and other human activities along 

the entire coastline (Stedman and Dahl, 2008). 

9 This study incorporated some estuarine embayments not included 

in the total land area figure.

10This study did not include any wetland losses due to the Deepwater 

Horizon oil spill in 2010 since the effective dates of data collection for 

this study were between 2004 and 2009.

10 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Table 1. Area (in acres) of coastal watersheds and shoreline (in miles) included in this study (shoreline information courtesy of 

NOAA, National Ocean Service).

Coastal Watershed Area of Coastal Watersheds 

(acres) Coastline (miles) Tidal Shoreline (miles)

Atlantic Coast 89,096,000 2,070 28,670

Gulf Coast 67,562,000 1,630 17,140

Great Lakes (United States 

only)

55,869,000 5,180 

(including connecting rivers)

NA

Pacific Coast 34,372,000 1,290 7,860

Total 246,899,000 10,170 53,670
Recognized collectively in federal law as the Nation’s 

“fourth seacoast”, the Great Lakes and their connecting 

channels and rivers comprise the world’s largest body 

of freshwater (U.S. Commission on Ocean Policy 2004). 

The watersheds of the Great Lakes encompass a diversity 

of habitats including glacial scours, coniferous forests, 

rocky shorelines and sand dunes. The coastal wetland 

ecosystems of the Great Lakes include about 30,000 

islands, bogs, fens, coastal marshes, coastal ridges and 

swales, shrub swamps, wet prairies, forested wetlands 

and alvars. Only a small percentage of the original extent 

of wetlands remains around the Great Lakes after over 

200 years of intensive development and urbanization 

(Mitsch and Wang 2000). 

For the first time this study included wetlands in 

the coastal watersheds of Washington, Oregon and 

California. These three states have 1,290 miles of 

shoreline extending from Puget Sound to the California – 

Mexico border, with more than 410 estuaries and bays 

(USEPA 2012). The Pacific coast lacks the extensive 

coastal plain found elsewhere in the U.S. and instead is 

characterized by steep topographic relief between land 

and sea. As a result, saltwater marshes and estuarine 

flats are found only in discontinuous segments. Intertidal 

wetlands are located principally in coastal embayments 

such as Grays Harbor, Willapa Bay and Puget Sound 

in Washington; the Columbia River Estuary, Coos Bay, 

Tillamook Bay and Yaquina Bay in Oregon; and 

Humboldt Bay, San Francisco Bay, Bolsa Chica Bay 

and the Tijuana Estuary in California. Since the 1850’s 

90 percent of California’s original coastal wetland 

acreage has disappeared, and many of the remaining 

wetlands are in danger of being further degraded or 

destroyed due to filling, diking, dredging, pollution and 

other human disturbances (CA Natural Resources Agency 

2013). The coastal areas of Oregon and Washington 

are somewhat less degraded than those of California, 

but dams and other water diversions affect the timing, 

quantity and quality of freshwater flows down rivers and 

into estuaries (Gleason et al. 2011). 

Study Area 11

Freshwater wetland on Madeline Island, Wisconsin. 

Figure 8. Coastal Watersheds of the 

Conterminous United States (shown in 

darker green) as used in this study.
Study Methods

1212 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009 

In the previous study by Stedman and Dahl (2008), and 

in the present study analysis of the USFWS National 

Wetlands Status and Trends dataset was conducted to 

provide updated information specifically on the status 

and extent of wetland resources in the coastal watersheds 

and the recent changes that had occurred. Randomly 

selected plots were assessed using digital high-resolution 

imagery to identify change in wetlands, deepwater 

habitats and uplands. Imagery used to detect changes 

included digital high resolution (<1 meter) multispectral 

or infrared satellite imagery as well as true color 

photography (1 meter resolution).11 Each sample plot 

was 4.0 square miles total area (2,560 acres). A total of 

2,614 plots were used to sample the coastal watersheds. 

Wetland, deepwater and upland habitat changes were 

determined by intensive analysis of the aerial imagery, 

determination of wetland types and identification of the 

changes that occurred between the respective target 

dates. The mean dates of the aerial imagery used to 

determine wetland trends were 2004 and 2009, with 

the difference being an average of 4.5 years. For this 

study, wetlands 1.0 acres and larger composed the 

target population.12 However, actual results indicated 

that for each wetland category included in the study, 

the minimum size represented was less than 1.0 acre. 

Additional information on the study design, data 

collection and analysis procedures has been discussed 

by Dahl (2011). Changes were recorded in areal extent 

or type of wetland observed on the sample plots between 

2004 and 2009. 

Ground verification of features on the aerial imagery 

was done for at least portions of 380 sample plots 

(14.5 percent) during 2009 and 2010. Field verification 

addressed questions regarding image interpretation, land 

use coding and attribution of wetland gains or losses. 

Field work was also performed as one of the quality 

control measures to verify that plot information was 

accurate. Verification involved field visits to a variety of 

wetland types and geographical settings. 

To reflect reliability, each statistical estimate generated 

is accompanied by a coefficient of variation expressed as 

a percent. The wetland area estimates produced for this 

study include all wetlands regardless of land ownership. 

The results represent the latest wetland monitoring 

information specific to the coastal watersheds areas of the 

Atlantic, Gulf or Mexico, Great Lakes and Pacific. 

11 About 40 percent of the sample sites used satellite imagery and 

60 percent aerial photography. 

12 Smaller wetlands were detected and included in the study, but it 

cannot be determined that all wetlands less than 1.0 acre were detected.

Cape Romain, South Carolina.
Habitat Definitions 13

Habitat Definitions

During the mid-1970s USFWS began work on a 

biological definition of wetland and standardized 

nomenclature for the classification of wetland types. This 

system described by Cowardin et al. (1979), was adopted 

as a standard by USFWS and subsequently became a 

Federal Geographic Data Committee (FGDC) Standard 

for mapping, monitoring and reporting on wetlands 

(FGDC 1996). This institutionalization of a biological 

definition and classification system has facilitated its 

use in numerous Federal applications and has provided 

consistency and continuity by defining the biological 

extent of wetlands and common descriptors for wetland 

types. It is a two-part definition as indicated below:

Wetlands are lands transitional between 

terrestrial and aquatic systems where the water 

table is usually at or near the surface or the land 

is covered by shallow water. 

For purposes of this classification wetlands 

must have one or more of the following three 

attributes: (1) at least periodically, the land 

supports predominantly hydrophytes, (2) the 

substrate is predominantly undrained hydric soil, 

and (3) the substrate is nonsoil and is saturated 

with water or covered by shallow water at some 

time during the growing season of each year.

Cowardin et al. (1979) and other researchers (Gosselink 

and Turner 1978; Mitsch and Gosselink 1993) recognized 

that hydrology was universally regarded as the most 

basic feature of wetlands and that hydrology, not the 

presence of vegetation, determines the existence of 

wetland (Cowardin and Golet 1995). For this reason, 

in areas that lack vegetation or soils (e.g. coastal mud 

flats, sand beaches, rocky bars and shorelines) hydrology 

determines that these areas are wetlands. In practice, 

three indicators - hydrophytic vegetation, undrained 

hydric soil, and wetland hydrology; two indicators 

- hydrophytic vegetation and wetland hydrology or 

undrained hydric soil and wetland hydrology; or a single 

indicator - wetland hydrology, may be used to identify 

wetland based on the conditions at any particular site 

(FGDC 2013).

Cowardin et al. (1979) defined “estuarine” and “marine” 

wetlands as saltwater systems; consequently no estuarine 

or marine wetlands were identified in the coastal 

watersheds of the Great Lakes portion of this study. 

Shoreline wetlands of the Great Lakes were included 

with other freshwater wetlands in the Great Lakes coastal 

watersheds.

Ephemeral waters, which are not recognized as a wetland 

type, and certain types of “farmed wetlands” as defined 

by the Food Security Act were not included in this study 

because they do not meet the Cowardin et al. definition. 

Habitat category definitions used in this study are given 

in synoptic form in Table 2. Complete definitions of 

wetland types and land use categories used in this study 

are provided in Appendix A.

Wetlands and deepwater habitats are defined separately 

by Cowardin et al. (1979) because the term wetland does 

not include deep, permanent water bodies. Deepwater 

habitats are permanently flooded land lying below the 

deepwater boundary of wetlands. Deepwater habitats 

include environments where surface water is permanent 

and often deep, so that water, rather than air, is the 

principal medium in which the dominant organisms 

live, whether or not they are attached to the substrate. 

For the purposes of conducting status and trends work, 

all lacustrine (lake) and riverine (river) waters as well 

as deep, open water estuaries and marine waters were 

considered deepwater habitats.

Upland included lands not meeting the definition of 

either wetland or deepwater habitats. An abbreviated 

upland classification system patterned after the 

U. S. Geological Survey land classification scheme 

described by Anderson et al. (1976), with five generalized 

categories, was used to describe uplands in this study. 

Blue Crab (Callinectes sapidus), Monroe County, Florida
Study Limitations

The identification and delineation of wetland habitats 

through image analysis formed the foundation for 

deriving the wetland status and trends data results 

reported here. Because of the limitations of aerial imagery 

as the primary data source to detect some wetlands, 

certain wetland types were excluded from study. These 

limitations included the inability to detect small wetland 

areas; inability to accurately detect or monitor certain 

types of wetlands such as seagrasses that may require 

hyperspectral or other specialized imagery or analysis 

techniques (Dierssen et al. 2003; Peneva et al. 2008), 

submerged aquatic vegetation, or submerged reefs (Dahl 

2005); and inability to consistently identify certain 

forested wetlands either because of their small size, 

canopy closure, or lack of visible hydrology. 

Freshwater wetland, Weeks Bay, Alabama

Table 2. Wetland, deepwater, and upland categories used to conduct this study. The definitions for 

each category appear in the Appendix.

Saltwater Habitats Common Description

Marine Subtidal* Open ocean

Marine Intertidal Near shore

Estuarine Subtidal* Open-water/bay bottoms

Estuarine Intertidal Emergents Salt marsh

Estuarine Intertidal Forested/Shrub Mangroves or other estuarine shrubs

Estuarine Intertidal Unconsolidated Shore Beaches/bars/shoals

Riverine* (may be tidal or non-tidal) River systems

Freshwater Habitats

Palustrine Forested Forested swamps

Palustrine Shrub Shrub wetlands

Palustrine Emergents Inland marshes/wet meadows

Palustrine Unconsolidated Bottom (ponds) Open-water ponds/aquatic bed

Lacustrine* Lakes and reservoirs

Uplands

Agriculture Cropland, pasture, managed rangeland

Urban Cities and incorporated developments

Silviculture Planted or intensively managed forests; silviculture

Rural Development Non-urban developed areas and infrastructure

Other Uplands Rural uplands not in any other category barren lands

*

Constitutes deepwater habitat

14 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009
Freshwater wetlands, Big Pine Key, Florida

Study Limitations15

Coastal marsh, Pettaquamscutt Cove, Rhode Island
Results: Status of Wetlands in Coastal Watersheds, 2009

In 2009, there were an estimated 41.1 million acres of 

wetlands in the coastal watersheds of the United States.13 

This area represented 37.3 percent of total wetland area in 

the conterminous U.S. Of the wetland area in the coastal 

watersheds, an estimated 34.6 million acres (84.3 percent) 

were freshwater wetland types and 6.4 million acres 

(15.7 percent) were saltwater as shown in Figure 9.

Saltwater wetlands were composed of estuarine emergent 

marshes, estuarine shrub wetlands and estuarine or marine 

non-vegetated wetland areas such as beaches, shoals, 

mud flats, coastal spits and sand bars. Estuarine emergent 

marshes were found to be the most prevalent saltwater 

wetland type making up an estimated 66.2 percent of all 

saltwater wetlands. Estuarine shrub wetlands and nonvegetated saltwater wetlands comprised an estimated 

12.4 percent and 21.3 percent by area, respectively, in 

2009.

Freshwater wetlands were found in each of the coastal 

watershed regions and made up an estimated 84 percent 

of the total wetland area of these watersheds in 2009. 

Freshwater wetlands were least prevalent in the Pacific 

watersheds and most abundant in the watersheds of the 

Atlantic. There were an estimated 20.8 million acres of 

forested wetland (this represented 60.2 percent of the 

area of all freshwater wetlands in the coastal watersheds). 

Freshwater shrub wetland area was estimated to have 

been 6.7 million acres (19.4 percent) with an estimated 

5.9 million acres (17.1 percent) of freshwater emergent 

marshes and 1.2 million acres (3.3 percent) of freshwater 

ponds in 2009. 

The watersheds of the Atlantic and Gulf of Mexico have 

very similar amounts of wetland area (15.9 million and 

15.4 million acres, respectively) with the Atlantic coastline 

having an estimated 460,000 acres more than the Gulf of 

Mexico. Watersheds of the Great Lakes had an estimated 

8.5 million acres of wetland. The Pacific coastal watersheds 

had the least amount of wetland with an estimated 

1.3 million acres. The percent of wetland area for each of 

the coastal regions in shown in Figure 10.

The distribution and relative wetland density of wetlands 

within the coastal watersheds in this study are shown in 

Figure 11.

13 Stedman and Dahl (2008) found 39.8 million acres of wetlands in the 

coastal watersheds. This study includes the additional coastal watershed 

area of the Pacific coast in Washington, Oregon and California.

Freshwater 

wetland area

Saltwater 

wetland area

84.3%

15.7%

Wetland Density

0−2%

3−4%

5−8%

9−12%

13−15%

16−25%

16 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009
0−5%

6−10%

11−15%

16−25%

26−40%

>40%

Wetland Density

Atlantic

20.7%

37.5%

38.7%

3.1%

Gulf of Mexico

Great Lakes

Pacific

Results 17

Figure 9. (Far left) Freshwater and saltwater wetland by 

area in the coastal watersheds (Atlantic, Gulf of Mexico, 

Great Lakes and Pacific), 2009.

Figure 10. (Left) Percent of all coastal wetland area by 

coastal region, 2009.

Figure 11. Relative wetland density of the coastal 

watersheds along the Atlantic, Gulf of Mexico, Great 

Lakes and Pacific as determined by this study, 2009
All saltwater (intertidal) wetlands in the conterminous 

U.S. (6.4 million acres) are located in the coastal 

watersheds. The distribution of saltwater wetland 

area in the coastal watersheds of the Atlantic, Gulf of 

Mexico and Pacific14 is shown in Figure 12. The coastal 

watersheds along the Gulf of Mexico had the largest 

saltwater wetland area in 2009 with 3.4 million acres. 

The Atlantic had an estimated 2.4 million acres and the 

Pacific slightly over 700,000 acres. There were fewer 

wetlands along the Pacific coast of Washington, Oregon 

and California as these coastlines are characterized by rock 

outcrops, and less extensive areas of coastal plain (Figure 13). 

Coastal watersheds of each coastal region also 

support considerable freshwater wetland types. An 

estimated 33.2 percent of all freshwater wetland area 

in the conterminous U.S. (Table 3) is located in these 

coastal watersheds. The Atlantic watersheds had the 

highest percentage with about 13.5 million acres of 

freshwater wetland. The Gulf of Mexico had slightly over 

12 million acres and the Great Lakes had 8.5 million acres. 

The Pacific coastal watersheds had the least amount of 

freshwater wetland area with an estimated 556,000 acres 

(Figure 14).

14 Because Cowardin et al. (1979) defines “marine” and “estuarine” 

wetlands as saltwater systems, no estuarine or marine wetlands were 

identified in the coastal watersheds of the Great Lakes portion of this 

study. All wetlands of the Great Lakes watersheds were freshwater 

wetlands.

Table 3. Estimated freshwater wetland area in the coastal watersheds of the Atlantic, Gulf of Mexico, Great Lakes and Pacific as 

compared to the conterminous United States, 2009. The coefficient of variation (CV) for each entry (expressed as a percentage) is 

given in parentheses.

Wetland Category

Area in Acres

Wetland in Coastal Watersheds, 

2009

Wetland in Conterminous U.S., 

2009

Percent Wetland Area in Coastal 

Watersheds, 2009

Freshwater Non-vegetated 

(ponds)1

1,145,503 6,709,300 17.1%

(4.5) (4.5)

Freshwater Forested 20,838,893 51,623,300 40.4%

(3.2) (2.7)

Freshwater Shrub 6,713,742 18,511,500 36.3%

(5.7) (4.2)

Freshwater Emergent 5,922,215 27,430,500 21.6%

(5.9) (7.6)

Freshwater Vegetated2 33,474,851 97,565,300 34.3%

(2.8) (2.9)

All Freshwater Wetlands 34,620,353 104,274,600 33.2%

(2.7) (2.8)

1

 Includes the category: Palustrine Unconsolidated Bottom.

2

 Includes the categories: Palustrine Forested, Palustrine Shrub and Palustrine Emergent.

18 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009
(52%)

(37%)

(11%)

3,349,800

2,377,700

713,800

Gulf of Mexico

Atlantic

Pacific

Great Lakes

Figure 12. Saltwater (intertidal) wetland distribution 

(area in acres) by coastal regions, 2009.

(34.8%)

(39%)

(1.6%)

12,061,700

13,490,900

555,700

8,512,100

(24.6%)

Figure 14. Freshwater wetland distribution (area in 

acres) by coastal regions, 2009.

Results: Staus of Wetlands in Coastal Watersheds, 2009 19

Figure 13. Rocky shoreline along the coast of California.
Changes in Wetlands of the Coastal Watersheds, 2004 to 2009

The estimated wetland area and changes for the coastal 

watersheds of the Atlantic, Gulf of Mexico, Great Lakes 

and Pacific from 2004 to 2009 are presented in Table 4. 

Differences between the 2004 estimates of all wetlands 

in coastal watersheds in this study as compared to 

estimates for the same time period reported by Stedman 

and Dahl (2008) were due to the addition of the Pacific 

coast wetland area that was not included previously.15

Collectively, saltwater and freshwater wetland area 

declined by an estimated 360,720 acres between 2004 

and 2009. The average annual rate of change for all 

wetlands in the coastal watersheds was a loss of 80,160 

acres over the period of this study. This was a 25 percent 

increase in the rate of coastal wetland loss reported for 

the period between 1998 and 2004.

The Atlantic, Gulf of Mexico and Pacific coastal regions 

experienced net wetland losses of 111,960 acres, 

257,150 acres and 5,220 acres, respectively. The 

watersheds of the Great Lakes region experienced a net 

gain in wetland area of an estimated 13,610 acres. Seventy 

one percent of the estimated wetland losses between 2004 

and 2009 were in the coastal watersheds of the Gulf of 

Mexico. 

There was an estimated net loss of 95,000 acres 

of saltwater wetlands. Modest gains in marine and 

estuarine non-vegetated wetland (flats, shoals and bars) 

were overshadowed by losses of estuarine vegetated 

wetlands which declined by 2.4 percent (Table 5). Most 

of the vegetated estuarine losses were to open saltwater 

(deepwater habitats) and virtually all of these losses 

occurred in the Gulf of Mexico. 

Freshwater wetlands overall, experienced a net loss of 

more than 265,000 acres. Freshwater pond area increased 

by almost six percent and freshwater emergent marshes 

and shrub wetlands also increased in area. However, 

freshwater forested wetlands declined by 405,700 acres 

resulting in a net loss of freshwater vegetated wetland area 

of 328,800 acres (1.0 percent) between 2004 and 2009.

Changes to wetland area between 2004 and 2009 by 

coastal region are graphically displayed in Figure 15.

15 When normalized the difference in the estimated total wetland 

area for 2004 between the two studies is <1.0 percent or within the 

statistical margin of error.

20,000

-20,000

0

-80,000

-60,000

-40,000

-100,000

-120,000

-140,000

-160,000

-180,000

Acres

Saltwater 

Wetland Loss

Freshwater 

Wetland Loss

Saltwater 

Wetland Gain

Freshwater 

Wetland Gain

Atlantic Gulf of Mexico Pacific Great Lakes

Coastal Region

20 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Figure 15. Wetland gains and 

losses in the coastal watersheds of 

each coastal region between 2004 

and 2009.
Table 4. Changes in wetland area for the coastal watersheds of the Atlantic, Gulf of 

Changes in the Wetlands of the Coastal Watersheds 21

Mexico, Great Lakes and Pacific, 2004 to 2009.

Coastal Region Wetland Area 2004 

(acres)

Wetland Area 2009 

(acres)

Net Change 

(acres)

Percent 

Change

Atlantic 15,980,550 15,868,594 -111,957 -0.7 %

Gulf of Mexico 15,668,626 15,411,472 -257,153 -1.6 %

Great Lakes 8,498,448 8,512,056 13,608 +0.2 %

Pacific 1,274,725 1,269,504 -5,221 -0.4 %

Total 41,422,348 41,061,625 -360,723 -0.9 %

*

Table 5. Estimated status and change in wetland area for selected categories in the coastal watersheds of the Atlantic, Gulf of 

Mexico, Great Lakes and Pacific, 2004 to 2009. The coefficient of variation (CV) for each entry (expressed as a percentage) is given 

in parentheses.

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Marine Intertidal 231,221 239,658 8,437 3.6%

(15.2) (14.8) (50.1)

Estuarine Intertidal 

Non-vegetated1

1,114,614 1,135,468 20,854 1.9%

(12.9) (12.7) (44.3)

Estuarine Intertidal 

Vegetated2

5,190,437 5,066,146 -124,290 -2.4%

(4.5) (4.5) (17.2)

All Intertidal (Saltwater) 

Wetlands

6,536,271 6,441,272 -94,999 -1.5%

(4.5) (4.5) (21.1)

Freshwater 

Non-vegetated3

1,082,424 1,145,503 63,079 5.8%

(4.6) (4.5) (23.3)

Freshwater Forested 21,244,634 20,838,893 -405,741 -1.9%

(3.2) (3.2) (19.6)

Freshwater Shrub 6,657,614 6,713,742 56,128 0.8%

(5.7) (5.7) (*)

Freshwater Emergent 5,901,405 5,922,215 20,811 0.4%

(5.9) (5.9) (*)

Freshwater Vegetated 

Wetlands4

33,803,653 33,474,851 -328,802 -1.0%

(2.7) (2.8) (19.6)

All Freshwater Wetlands 34,886,077 34,620,353 -265,723 -0.8%

(2.6) (2.7) (23.8)

All Wetlands 41,422,349 41,061,625 -360,723 -0.9%

(2.3) (2.3) (19.0)

 Statistically unreliable

1

 Includes the category: Estuarine Intertidal Unconsolidated Shore 

2

 Includes the categories: Estuarine Intertidal Emergent and Estuarine Intertidal Shrub

3

 Includes the categories: Palustrine Unconsolidated Bottom 

4

 Includes the categories: Palustrine Emergent, Palustrine Forested and Palustrine Shrub.
Trends in Saltwater Wetlands, 2004 to 2009

The majority of saltwater (estuarine and marine) wetlands 

fall into three types: estuarine intertidal emergent 

wetlands (salt and brackish water marshes), estuarine 

shrub wetlands (mangrove swamps and other salt-tolerant 

woody species), and marine or estuarine intertidal nonvegetated wetlands. The latter category included exposed 

coastal beaches subject to tidal flooding, as well as sand 

bars, tidal mud flats, shoals and sand spits. 

There were an estimated 6,441,300 acres of saltwater 

wetlands in the conterminous U.S. in 2009. Nonvegetated wetland types experienced considerable 

amount of change related to the constantly changing 

shape of the coastline. Estuarine vegetated wetlands 

experienced a decline of 124,300 acres between 2004 

and 2009. As was seen in the earlier study covering 1998 

to 2004, loss to open saltwater was responsible for the 

majority of these losses (Figure 16). 

Saltwater wetland (vegetated and non-vegetated) area 

declined by an estimated 1.5 percent. This represented 

a 35 percent increase over the rate of saltwater wetland 

loss reported by Stedman and Dahl (2008) for the period 

between 1998 and 2004. The increased loss rate was 

attributed to accelerated losses in the Gulf of Mexico 

where the estimated rate of saltwater wetland loss more 

than doubled from 44,800 acres between 1998 and 2004 

to 95,300 acres between 2004 and 2009 (Figure 17). 

These losses accounted for 99 percent of all saltwater 

wetland losses to open deepwater between 2004 and 

2009. Saltwater wetland losses in the Gulf of Mexico 

have been attributed to the effects of severe coastal 

storms16 such as Hurricanes Katrina and Rita in 2005 and 

Hurricane Ike in 2008, which inundated wetlands with 

storm surge, abnormally high tides, increased rainfall, 

runoff, increased sediment and debris deposition and 

16 Coastal storms include tropical storms, hurricanes and winter 

storms.

Freshwater 

Wetlands

Upland 

Development

Other

Uplands

Open

Saltwater

20,000

-40,000

-120,000

-100,000

-80,000

-60,000

0

Acres

-20,000

22 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Figure 16. Attribution of loss or conversion of saltwater wetlands in the coastal watersheds of the Atlantic, Gulf of Mexico and 

Pacific, 2004 to 2009
Acres

0 −100

101−300

301−700

701−2500

2501−4510

TEXAS

LOUISIANA MISSISSIPPI

ALABAMA

FLORIDA

Trends in Saltwater Wetlands 23

Figure 17. Coastal watersheds of the upper Gulf of Mexico showing the magnitude of saltwater (intertidal) wetland loss to open water, 2004 

to 2009.

erosion. Considerable losses of wetland area resulted 

from Hurricane Katrina alone (Costanza et al. 2006). 

By comparison, a small percentage of saltwater wetland 

losses have been traced to discrete anthropogenic 

actions17 in the Gulf of Mexico.

In contrast, the coastal watersheds of the Atlantic 

experienced a small net gain of about 330 acres 

(<1.0 percent) of saltwater wetlands (Table 6)18. Intertidal 

non-vegetated wetlands increased by approximately 

2,200 acres and estuarine shrub wetlands increased by 

approximately 4,400 acres between 2004 and 2009. 

Saltwater inundation of freshwater wetlands and some 

uplands, primarily along the Atlantic coastline near 

Delaware Bay, coastal South Carolina and Georgia and 

in the Gulf of Mexico along the coast of central Florida, 

coastal Louisiana and Texas, resulted in the conversion 

of an estimated 7,800 acres of freshwater wetland and 

1,940 acres of upland to become saltwater wetlands. 

However, there was also an estimated loss of 7,360 acres 

of estuarine saltmarsh in the coastal watersheds of the 

Atlantic. The majority of the losses in estuarine marsh 

area were attributed to erosion and/or inundation related 

to increases in sea level predominately along shorelines 

near Delaware Bay. 

The density and distribution of saltwater wetlands in the 

Pacific coastal watersheds was very different compared to 

other coastlines. The watersheds of the Pacific contained 

the least amount of coastal wetland area and the Pacific 

was the only coastline where saltwater wetland area 

exceeded freshwater wetland. The tidal range in some 

of the northwestern tidal wetlands can exceed 9-10 feet 

(Seliskar and Gallagher 1983), which contributes to the 

formation of extensive coastal sand and mud flats. An 

estimated 70 percent (497,500 acres) of all intertidal 

wetlands19 in the watersheds of the Pacific coast were 

non-vegetated. The remaining 30 percent were emergent 

saltmarsh wetlands that were found fringing the borders 

of rivers that flowed to the coast (Figure 18). There was 

very little change in any of the saltwater wetland types in 

the Pacific coastal watersheds between 2004 and 2009. 

The overall net change was an estimated loss of about 

40 acres. 

19 Includes marine intertidal and estuarine intertidal non-vegetated 

wetlands. 

17 Land subsidence and sea level rise may be attributed to human 

actions but could not be traced to a specific event or spatial change such 

as wetland fill, drainage or otherwise mechanically altering wetland area.

18 These estimates pre-date any coastal wetland changes resulting 

from Hurricane Sandy that struck the Atlantic seaboard in 2012
Table 6. Estimated changes to saltwater (intertidal) wetlands of the Atlantic (A), Gulf of Mexico (B) and Pacific (C) 

coastal watersheds, 2004 to 2009. (The Coefficient of Variation [CV] for each entry is given in the parentheses.)

A. Estimated Changes to Saltwater Wetlands of the Atlantic Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Marine Intertidal 106,526 107,609 1,084 1.0%

(23.4) (23.2) (*)

Estuarine Intertidal 

Non-vegetated1

302,473 304,684 2,211 0.7%

(17.5) (17.4) (98.5)

 Estuarine Emergent 1,846,327 1,838,965 -7,362 -0.4%

(6.8) (6.8) (61.9)

 Estuarine Shrub 122,037 126,433 4,397 3.6%

(15.3) (15.1) (73.9)

Estuarine Intertidal 

Vegetated2

1,968,363 1,965,398 -2,965 -0.2%

(6.5) (6.5) (*)

All Intertidal (Saltwater) 

Wetlands

2,377,362 2,377,691 329 0.0%

(6.5) (6.4) (*)

B. Estimated Changes to Saltwater Wetlands of the Gulf of Mexico Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Marine Intertidal 33,146 40,499 7,353 22.2%

(35.5) (30.7) (52.3)

Estuarine Intertidal 

Non-vegetated1

406,222 424,865 18,643 4.6%

(13.9) (13.3) (48.1)

 Estuarine Emergent 2,332,470 2,211,674 -120,796 -5.2%

(6) (6.1) (17.4)

 Estuarine Shrub 673,236 672,750 -486 -0.1%

(14.8) (14.6) (*)

Estuarine Intertidal 

Vegetated2

3,005,706 2,884,424 -121,282 -4.0%

(5.7) (5.8) (17.3)

All Intertidal (Saltwater) 

Wetlands

3,445,073 3,349,788 -95,285 -2.8%

(5.3) (5.4) (20.4)

 Statistically unreliable

1

 Includes the category: Estuarine Intertidal Unconsolidated Shore 

2

 Includes the categories: Estuarine Intertidal Emergent and Estuarine Intertidal Shrub

24 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

*
Trends in Saltwater Wetlands   ﻿  25

Figure 18. Tidal saltmarsh in coastal Washington. This study found 30 percent of saltwater wetlands along in the Pacific coastal 

watersheds were emergent saltmarsh.

Table 6. Estimated changes to saltwater (intertidal) wetlands of the Atlantic (A), Gulf of Mexico (B) and Pacific (C) 

coastal watersheds, 2004 to 2009. (The Coefficient of Variation [CV] for each entry is given in the parentheses.)—Continued

C. Estimated Changes to Saltwater Wetlands of the Pacific Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Marine Intertidal 91,549 91,549 0 0.0%

(23.9) (23.9) (0)

Estuarine Intertidal 

Non-vegetated1

405,919 405,919 0 0.0%

(29.9) (29.9) (0)

 Estuarine Emergent 216,313 216,269 -43 0.0%

(39.4) (39.4) (99)

 Estuarine Shrub 55 55 0 0.0%

(98.7) (98.7) (0)

Estuarine Intertidal 

Vegetated2

216,367 216,324 -43 0.0%

(39.4) (39.4) (99)

All Intertidal (Saltwater) 

Wetlands

713,836 713,793 -43 0.0%

(24) (24) (99)

 Statistically unreliable

1

 Includes the category: Estuarine Intertidal Unconsolidated Shore

2

 Includes the categories: Estuarine Intertidal Emergent and Estuarine Intertidal Shrub

*
Trends in Coastal Freshwater Wetlands, 2004 to 2009

Overall, freshwater wetlands declined by an estimated 

265,720 acres (0.8 percent) between 2004 and 2009. 

Regionally, there was a small net loss (5,180 acres) along 

the Pacific, net losses of 112,290 acres along the Atlantic, 

large net losses (161,870 acres) along the Gulf of Mexico 

and a modest net gain of 13,610 acres in the watersheds 

of the Great Lakes. The estimated changes to freshwater 

wetland types by coastal region are shown on pages 

28–29 in Table 7. There were gains in area of freshwater 

shrub wetlands, emergent wetlands, and ponds; however 

these gains were offset by large losses of freshwater 

forested wetlands (Figure 19). 

Forested wetland area declined by an estimated 

405,740 acres between 2004 and 2009, a decrease 

of 1.9 percent. Forested wetlands declined in each of 

the coastal watershed areas with the exception of the 

Great Lakes. The greatest amount of change occurred 

in coastal watersheds from North Carolina to Florida 

on the Atlantic, and Florida to Texas on the Gulf of 

Mexico, where forested wetland area declined by an 

estimated 443,780 acres between 2004 and 2009. Of 

this total change in forested wetland area, 63 percent 

of the acreage was cleared and converted to other 

wetland types, such as freshwater shrubs. An estimated 

36 percent (158,340 acres) was lost to upland land 

uses. A comparatively small increase of an estimated 

47,940 acres of forested wetlands in the Great Lakes 

region offset some of the large losses of forested 

wetlands in the southeastern U.S. The estimated losses 

of freshwater forested wetland in the coastal watersheds 

made up over 64 percent of all forested losses in the 

conterminous U.S. between 2004 and 2009; thus the 

causes for those losses have far reaching implications 

for wetland management, protection and regulation 

strategies. The activities that converted forested wetland 

to upland in the southeastern U.S. and the amount of 

loss attributed to those activities are shown in Figure 20.

100,000

-100,000

-500,000

-400,000

-300,000

-200,000

0

Emergent Shrub Forested Ponds All Freshwater 

Types

Acres

26 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Figure 19. Estimated losses and gains in area for the freshwater wetland types in the coastal watersheds of the Atlantic, 

Gulf of Mexico, Great Lakes and Pacific, 2004 to 2009
44.3%

39.1%

10.2%

6.1%

Development

Silviculture

Other Uplands

Agriculture

Figure 20. Forested wetland losses in the coastal watersheds of the Southeastern U.S. (North Carolina to Texas) 

as attributed to upland land use categories, 2004 to 2009. Total forested wetland losses to upland in this region were 

estimated to have been 158,340 acres over the years covered by this study.

Trends in Coastal Freshwater Wetlands 27

Freshwater forested wetland near Weeks Bay, Alabama.
Table 7. Estimated changes to freshwater wetlands of the Atlantic (A), Gulf of Mexico (B), Great Lakes (C), and Pacific (D)

coastal watersheds, 2004 to 2009. (The Coefficient of Variation [CV] for each entry is given in the parentheses.)

A. Estimated Changes to Freshwater Wetlands of the Atlantic Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Freshwater Non-vegetated 

(ponds)1

424,868 457,646 32,778 7.7%

(8.8) (8.4) (29.3)

Freshwater Forested 8,708,003 8,503,633 -204,370 -2.3%

(3.9) (3.9) (29.6)

 Freshwater Shrub 2,607,902 2,623,595 15,692 0.6%

(7.9) (8) (*)

 Freshwater Emergent 1,862,415 1,906,028 43,614 2.3%

(10.3) (9.9) (83.9)

Freshwater Vegetated2 13,178,320 13,033,256 -145,064 -1.1

(3.4) (3.4) (29.4)

All Freshwater Wetlands 13,603,188 13,490,902 -112,286 -0.8%

(3.3) (3.3) (37.3)

All Wetlands3 15,980,550 15,868,594 -111,957 -0.7%

(2.9) (2.9) (37.3)

B. Estimated Changes to Freshwater Wetlands of the Gulf of Mexico Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Freshwater Non-vegetated 

(ponds)1

376,721 407,641 30,919 8.2%

(6.5) (6.3) (30)

Freshwater Forested 7,311,885 7,063,638 -248,247 -3.4%

(5.1) (5.1) (19.3)

 Freshwater Shrub 1,744,905 1,802,400 57,495 3.3%

(9.6) (9.5) (77.3)

 Freshwater Emergent 2,790,041 2,788,005 -2,035 -0.1%

(9.5) (9.4) (*)

Freshwater Vegetated2 11,846,831 11,654,043 -192,788 -1.6%

(4.1) (4.2) (24.3)

All Freshwater Wetlands 12,223,552 12,061,684 -161,868 -1.3%

(4) (4) (28.6)

All Wetlands3 15,668,626 15,411,472 -257,153 -1.6%

(3.3) (3.3) (20.8)

28 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

 Statistically unreliable

1

 Includes the category: Palustrine Unconsolidated Bottom 

2

 Includes the categories: Palustrine Forested, Palustrine Shrub and Palustrine Emergent

3

 Includes all freshwater and saltwater wetlands 

*
Table 7. Estimated changes to freshwater wetlands of the Atlantic (A), Gulf of Mexico (B), Great Lakes (C), and Pacific (D)

coastal watersheds, 2004 to 2009. (The Coefficient of Variation [CV] for each entry is given in the parentheses.) —Continued

C. Estimated Changes to Freshwater Wetlands of the Great Lakes Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area, 2009 Change, 2004 to 2009 Change (percent)

Freshwater Non-vegetated 

(ponds)1

230,418 229,254 -1,163 -0.5%

(9) (9.6) (*)

Freshwater Forested 5,066,597 5,114,536 47,940 0.9%

(9.2) (9.1) (41.3)

 Freshwater Shrub 2,191,113 2,174,479 -16,635 -0.8%

(12.3) (12.3) (*)

 Freshwater Emergent 1,010,320 993,787 -16,534 -1.6%

(11.7) (11.9) (93.3)

Freshwater Vegetated2 8,268,030 8,282,802 14,771 0.2%

(7.7) (7.7) (73)

All Freshwater Wetlands 8,498,448 8,512,056 13,608 0.2%

(7.5) (7.5) (74.5)

All Wetlands3 8,498,448 8,512,056 13,608 0.2%

(7.5) (7.5) (74.5)

D. Estimated Changes to Freshwater Wetlands of the Pacific Coast

Wetland Category

Area in Acres

Estimated Area, 2004 Estimated Area,2009 Change, 2004 to 2009 Change(percent)

Freshwater Non-vegetated 

(ponds)1

50,417 50,961 544 1.1%

(12) (12.3) (*)

Freshwater Forested 158,150 157,085 -1,064 -0.7%

(27.8) (28) (46.9)

 Freshwater Shrub 113,693 113,269 -424 -0.4%

(23.1) (23.2) (*)

 Freshwater Emergent 238,629 234,395 -4,234 -1.8%

(22.6) (23) (65)

Freshwater Vegetated2 510,472 504,750 -5,722 -1.1%

(15.9) (16.1) (53.7)

All Freshwater Wetlands 560,889 555,711 -5,178 -0.9%

(14.7) (14.8) (59)

All Wetlands3 1,274,725 1,269,504 -5,221 -0.4%

(15.5) (15.5) (58.5)

 Statistically unreliable 

1

 Includes the category: Palustrine Unconsolidated Bottom 

2

 Includes the categories: Palustrine Forested, Palustrine Shrub and Palustrine Emergent

3

 Includes all freshwater and saltwater wetlands 

Trends in Coastal Freshwater Wetlands 29

*
Although there was an overall increase in freshwater 

emergent wetland area, emergent marshes declined 

along every coastline with the exception of the Atlantic 

where there was a net gain of an estimated 43,610 acres. 

The majority of this increase was attributed to the 

reestablishment of emergent wetlands in areas formerly 

classified as upland agriculture, other conservation 

practices or land retirement.

Freshwater shrubs exhibited an increase of 56,120 acres 

in the conterminous U.S. Freshwater shrub wetlands 

declined in the coastal watersheds of the Pacific and 

Great Lakes but increased in the coastal watersheds of the 

Atlantic and Gulf of Mexico. Freshwater shrub wetland 

area increased as freshwater forests in the southeastern 

U.S. were cleared and the areas were reclassified as 

shrub wetlands.

Freshwater ponds increased in area by an estimated 

5.8 percent between 2004 and 2009. Urban ponds 

increased in area by 19 percent or 55,700 acres while 

natural ponds declined in area by 3.9 percent or 

16,400 acres. The vast majority of these new ponds 

(99 percent) were constructed in the watersheds of the 

Atlantic and Gulf of Mexico and many were located 

in urban or suburban developments as likely water 

detention or ornamental ponds as opposed to targeted 

wetland reestablishment projects (Figure 21). 

30 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Figure 21. This aerial image shows the proliferation of freshwater ponds in a south Florida coastal watershed overtaken by development. 

Many vegetated wetlands have been replaced by artificially created, open water ponds (darker areas).
Overall, the largest land use associated with freshwater 

wetland loss in coastal watersheds was silviculture, 

followed by development (both urban and rural), 

which together account for 84 percent of the wetland 

loss. Freshwater wetland loss to deepwater habitats or 

saltwater wetlands is a smaller percentage of the total loss 

(16 percent), and a small amount of freshwater wetlands 

were gained from agricultural lands and other uplands. 

The loss or conversion of all freshwater wetlands from 

2004 to 2009 is shown in Figure 22. 

100,000

50,000

-200,000

-150,000

-100,000

-50,000

0

Acres

Deepwater Intertidal

Wetlands

Agriculture Other 

Uplands

Silviculture Urban 

and Rural

Development

Trends in Coastal Freshwater Wetlands 31

Figure 22. Attribution of loss or conversion of freshwater wetlands in the coastal watersheds, 2004 to 2009.
32 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Discussion

Similar to the previous coastal wetland study conducted 

by Stedman and Dahl (2008), the majority of the 

estimated wetland losses in coastal watersheds between 

2004 and 2009 occurred in the freshwater system and 

were attributed to different types of human activity 

that converted wetlands to uplands. Understanding 

the underlying cause(s) of these losses is important, 

particularly as they relate to efforts to adjust policy or 

management strategies to reverse this trend. Based on 

this study, the following issues appear to be central to 

understanding the ongoing loss of wetlands in coastal 

watersheds.

Lack of Reestablishment of 

Wetlands in Coastal Watersheds

Past studies of wetlands in the conterminous United 

States have documented losses that total about half of the 

wetland acreage that existed pre-European colonization 

(Dahl 1990). The Clean Water Act of 1977 (CWA)20 and 

other federal and state laws protecting wetlands have 

decreased losses, and reestablishment programs have 

reversed some losses. For the Nation as a whole, there 

has been a marked decrease in the overall rate of wetland 

loss since 1998. One of the federal strategies to help 

reduce wetland losses has been to promote and enable 

wetland reestablishment and creation projects. This 

strategy has enjoyed some success and some wetland 

losses have been offset by wetland reestablishment, 

especially in agricultural areas (Dahl 2011). 

Results from this study indicated that some wetland 

losses in coastal watersheds were being offset by wetland 

reestablishment and creation projects. For example, 

there were net gains in freshwater wetland area from 

agricultural lands (50,230 acres) and lands classified 

as “other uplands” (15,290 acres) (Figure 23). Coastal 

wetland gains occurred through reestablishment projects, 

changes in coastal geomorphology and in response 

to changing hydrology. Wetland reestablishment as 

measured by the conversion from upland to wetland21

was most prevalent on agricultural lands primarily in 

the coastal watersheds of South Carolina, Georgia and 

the upper reaches of the watersheds in central Florida 

and in the watersheds of the Great Lakes. In the Great 

Lakes watersheds historical conversion of wetlands to 

agricultural land uses through ditching and draining 

(Miller et al. 2012) has provided ample possibilities for 

wetland reestablishment.

However, the strategy of offsetting wetland losses with 

wetland reestablishment and creation does not appear 

to be as effective in coastal watersheds as it has been 

nationally. Wetland losses in coastal watersheds have 

continued to outdistance wetland gains, by an estimated 

360,720 acres between 2004 and 2009. This rate of loss 

increased by 25 percent since the previous reporting 

period of 1998 to 2004,22 and these continued losses of 

wetlands have direct costs for people and longer-term 

resource implications for fish, wildlife and other natural 

resources. 

Several factors are likely responsible for wetland 

reestablishment in coastal watersheds lagging behind 

reestablishment rates nationally, including the logistical 

difficulties of working in coastal ecosystems, competing 

land use interests and higher costs to reestablish coastal 

wetlands (Stedman and Dahl 2008). The reestablishment 

of intertidal wetlands poses unique challenges related to 

their complex linkages to terrestrial and marine habitats 

(Atkinson 2003). Sustainable wetland reestablishment 

opportunities in coastal watersheds are further limited by 

geography, human encroachment, land-use resulting in 

fewer suitable sites, geophysical processes from the sea 

that hamper reestablishment efforts (i.e. coastal storms, 

sea level rise, erosion and subsidence) and the amount of 

historic wetland area available for reestablishment. Some 

coastal watersheds have been developed to a point where 

wetland reestablishment or mitigation opportunities may 

be very limited given the changes in regional hydrology 

or the current land use. These changes reduce the 

chances for successful implementation of a watershedbased approach for compensatory mitigation of wetland 

losses.

20 The Clean Water Act of 1977 [P.L. 95217] (U.S. Army Corps of 

Engineers 1987)

21 Emergent wetlands typify wetland reestablishment projects.

22 Some of these increased losses were due to the addition of the 

Pacific coastal watersheds which contributed about 1,160 acres per year 

to the overall wetland loss rate.
 33

Figure 23. The term “Other” lands has been used to describe land in transition 

when it was not possible to categorize a distinguishable land use (e.g. urban or 

agriculture). In this photograph, a coastal freshwater wetland has been filled 

(loss in area) but the land use could not be determined (Louisiana, 2009).

Wetland Gains and Loss Examples on “Other” Lands (Undetermined Land Use)

This study found an estimated 15,290 acre net increase in freshwater wetland came from uplands 

classified as “other” lands or lands with undetermined land use. 

Other lands have included areas such as prairie, unmanaged or non-patterned upland forests, 

scrub lands, barren and abandoned land, lands enrolled in set-aside programs, conservation 

easement or other lands designated as wildlife management areas. Lands in transition may also 

fit into this category when land has been cleared but not yet developed to the point of a 

distinguishable land use (Figure 23).
Tidal salt marsh, Washington
Losses to Development

Of the estimated freshwater wetland losses to upland, 

urban and rural development accounted for an estimated 

97,800 acres or 37 percent (Figure 24). Urban and rural 

development was an important factor in wetland loss 

in coastal watersheds during the previous time period 

(1998-2004) as well (Stedman and Dahl, 2008). Coastal 

development has been identified by local stakeholders 

as a serious threat to coastal wetlands due to the direct 

and indirect effects of residential and commercial 

development, associated recreational development 

and expansion of supporting infrastructure including 

roads, bridges and utilities (USEPA 2013a). There is 

general recognition that once wetlands are lost through 

development, the loss of their functions and values 

is often irreversible (Mitsch and Gosselink 2000). 

Recognizing the potential for degradation of the Nation’s 

waters, the U.S. Congress enacted the CWA to maintain 

and restore the chemical, physical and biological 

integrity of the waters of the United States. Section 404 

of the Act requires avoidance and minimization of 

impacts to aquatic resources, including wetlands, and 

requires compensatory mitigation to offset losses that 

result from authorized development. Development can 

and does occur without authorization or in wetlands 

not under CWA jurisdiction. An area considered to be a 

wetland under the Cowardin classification system may 

or may not be a wetland under jurisdiction or it may be 

exempt from protection under the CWA for a number of 

reasons including how wetlands are delineated per the 

Army Corps of Engineers Wetland Delineation Manual 

(U.S. Army Corps of Engineers 1987) or recent Supreme 

Court rulings that have limited the CWA’s jurisdiction. 

The CWA has undoubtedly reduced the loss of coastal 

wetlands to development, but not eliminated it.

Some states have implemented wetland regulatory 

programs governed by rules and/or state statutes that may 

extend protection beyond the jurisdiction of the CWA.

Discussion 35

Figure 24. A residential housing development built on filled wetland in the upper portion of a coastal watershed in Louisiana.
Forested Wetlands and Silviculture

This study found that forested wetland area declined by 

an estimated 443,780 acres in the coastal watersheds of 

the southeastern U.S. between 2004 and 2009. Of this 

total change in forested wetland area, 63 percent of the 

acreage was cleared and converted to other wetland 

types, but was not considered a wetland loss, and an 

estimated 36 percent (158,340 acres) was lost to upland 

land uses. Of the forested wetland area lost to upland, 

an estimated 44 percent or 69,700 acres were attributed 

to silvicultural practices in the southeastern coastal 

watersheds. Other studies have also reported substantial 

changes to wetlands due to silviculture practices (USEPA 

2013a; Swords 2012; Dahl 2011; 1999; NCSU 2008). 

Harvesting or the removal of trees from forested wetlands 

does not, in itself, constitute a wetland loss.23 However, 

some activities associated with forested plantations 

involve drainage ditching, intensive site preparations, 

timber stand management and harvest practices that 

can alter or eliminate site hydrology, thereby causing 

a loss of wetland. Under Section 404 of the CWA a 

permit is not required for the discharge of dredged or fill 

material associated with normal silviculture activities 

or the construction of and maintenance of forest roads. 

However, the CWA and implementing regulations also 

state that activities that convert “waters of the United 

States” to upland always require authorization under 

Section 404. These two concepts, that certain actions are 

exempt from the federal wetland regulatory process and 

that any action that converts wetlands as waters of the 

United States always requires authorization seem to be 

at odds and in practice, it is unclear whether silvicultural 

practices that cause the loss of wetlands are fully 

understood or addressed in a consistent manner under 

the existing regulatory provisions.

A Memorandum to the Field issued by EPA and the 

Army Corps of Engineers in 1995 provided specific 

guidance for pine plantations in the southeast U.S. on 

the circumstances where mechanical silvicultural site 

preparation activities will or will not require a permit. 

Mechanical silvicultural site preparation activities in 

seasonally flooded and other wetter wetland types 

require a permit (USEPA 2010). Other forested wetlands 

including temporarily flooded or saturated forested 

areas do not require a permit for silvicultural activities, 

although a number of Best Management Practices are 

recommended to minimize impacts. When applied to the 

southeastern coastal watersheds, this guidance means 

that no CWA permit is required for silvicultural activities 

in approximately 6.5 million acres of forested wetlands 

including pine flatwood wetlands, seepage forests, 

saturated hammocks, pond pine woodland and forested 

wet flats. It was in these forested habitats that wetland 

losses were the greatest. 

23 A wetland was not considered lost unless there was sufficient 

artificial drainage, ditching or filling to substantially alter hydrology. 

Removal of tree canopy without hydrologic alteration resulted in change 

in wetland classification (i.e. forest to shrub wetland or forest to 

emergent wetland).

36 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

White ibis (Eudocimus albus), Corkscrew Swamp Sanctuary, Florida 
Losses of Saltwater Wetlands

Saltwater wetland losses were observed most notably 

in the Gulf of Mexico where erosion and/or inundation 

were the primary causes of these losses. Throughout the 

northern coastal region of the Gulf of Mexico, saltwater 

wetlands have been adversely affected by the cumulative 

effects of oil and gas development (Dahl 2011)24 which 

has increased the vulnerability of these wetlands to 

climate related changes (Twilley 2007) such as increased 

frequency and intensity of hurricanes and other coastal 

24 This study did not address impacts from the Deepwater Horizon oil 

spill in 2010. 

storm events. Costanza et al. (2008) cited the experience 

of Hurricane Katrina as an example of the enormous 

costs incurred by allowing coastal wetlands to degrade. 

Although Louisiana has developed a comprehensive 

plan25 to protect and restore the remainder of the states 

coastal wetlands, other Gulf of Mexico states are only 

beginning this process prompted by the need to plan 

for restoration of the damage caused by the Deepwater 

Horizon oil spill of 2010.

25 Coast 2050: Toward a Sustainable Coastal Louisiana. http://www.

coast2050.gov/

Discussion   ﻿  37

Mud flats, Picnkney Island NWR, South Carolina.
38 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Summary

This study examined recent trends in coastal wetland 

extent and type throughout the coastal watersheds of 

the conterminous United States. Wetland trends were 

measured by the examination of remotely sensed imagery 

for 2,614 sample plots in the coastal watersheds of 

the Atlantic, Gulf of Mexico, Great Lakes and Pacific. 

Wetlands and deepwater habitats were described using 

the USFWS biological definition of wetland as defined 

by Cowardin et al. (1979). The information in this study 

provides a quantitative measure of the areal extent of all 

wetlands, regardless of ownership, but does not draw 

conclusions about trends in the quality or condition of 

wetlands in the coastal watersheds. The data provide 

baseline information to facilitate ongoing collaborative 

efforts to assess coastal wetland losses and conservation. 

The study found that in 2009 there were an estimated 

41.1 million acres of wetlands in the coastal watersheds 

of the Atlantic, Gulf of Mexico, Great Lakes and Pacific. 

This represented 37.3 percent of the total wetland area in 

the conterminous U.S. 

Changes in wetland area between 2004 and 2009 

indicated that the coastal watersheds of the Atlantic 

declined by an estimated 111,960 acres. The Gulf 

of Mexico sustained larger losses of an estimated 

257,150 acres and the watersheds of the Pacific 

5,220 acres. The watersheds of the Great Lakes had a net 

gain in wetland area of an estimated 13,610 acres.

Both saltwater and freshwater wetlands sustained 

net losses between 2004 and 2009. There were an 

estimated 95,000 acres of saltwater wetland losses and 

265,720 acres of freshwater wetland losses.

Between 2004 and 2009, wetlands in the coastal 

watersheds declined by an estimated 360,720 acres or 

80,160 acres per year. This rate of wetland loss was about 

six times greater the estimated rate of wetland loss for 

the entire Nation for the same time period.26 The average 

annual rate of wetland loss in the coastal watersheds 

has increased by 25 percent over the previous reporting 

period. This increase in the rate of coastal wetland loss 

was statistically significant (p = 0.007) when results from 

this study were compared to the coastal wetland loss 

estimates from 1998 to 2004.

The increase in the rate of wetland loss was attributed 

to losses of saltwater wetlands in the Gulf of Mexico 

resulting from coastal storms in combination with 

freshwater wetland losses in both the Atlantic and Gulf of 

Mexico in the southeastern U.S. Large losses of freshwater 

forested wetland area were attributed to urban and rural 

development as well as silvicultural operations.

Wetlands in the coastal watersheds make up an 

increasingly fragile network of lands that continue 

to shrink in area. In coming years sea level rise 

threatens inundation or displacement of coastal lands, 

infrastructure and ecosystems (Day et al. 2008; Tebaldi 

et al. 2012). Dealing with the impacts of sea level rise 

will include a mix of engineering solutions and adaptive 

management strategies which, depending on their 

implementation, may have substantial impacts on coastal 

wetland systems.

In the upper portions of the coastal watersheds, 

stressors associated with residential and infrastructure 

development or land use changes that alter wetland 

distribution and extent continue to constrict wetland area. 

Of particular concern is the continued loss of vegetated 

wetlands to human related causes. In some regards, our 

understanding of coastal processes and interactions has 

not kept pace with the cumulative impacts resulting from 

wetland loss due to human-induced actions. 

In some parts of coastal watersheds, wetlands are 

vulnerable to both development on the landward side 

and coastal ocean processes from the sea. This has 

imposed considerable challenges for coastal wetland 

resource management, including mitigation options. 

At the Federal level there is recognition that more needs 

to be done to curtail wetland losses and to effectively 

protect and restore wetlands in the coastal watersheds 

26 From 2004 to 2009 wetlands declined by an estimated 

62,300 acres, nationally (13,800 acres per year).
as these efforts are important to coastal and marine 

habitat conservation (National Ocean Council 2013). 

To better address imminent threats to coastal wetlands, 

federal agencies have been working collaboratively to 

understand the underlying causes of coastal wetland 

loss and how wetland trends are affected by wetland 

regulatory processes, land utilization practices and 

trends, and other factors. Those efforts have factored 

into the development of the National Ocean Policy 

Implementation Plan (National Ocean Council 2013) 

that describes specific actions Federal agencies will take 

to address key challenges and promote stewardship of 

coastal resources. The data in this report provide new and 

more comprehensive information about coastal wetland 

trends and may be instrumental in further formulation of 

recommendations to improve the management of wetlands 

in coastal watersheds, reduce losses and ensure that 

coastal infrastructure and resources are protected.

Summary  39

Pee Dee River, South Carolina. 
40 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

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Appendix 43

APPENDIX: Definitions of Habitat Categories

Wetlands27 In general terms, wetlands are lands where saturation with water is the dominant 

factor determining the nature of soil development and the types of plant and 

animal communities living in the soil and on its surface. The single feature that 

most wetlands share is soil or substrate that is at least periodically saturated with or 

covered by water. The water creates severe physiological problems for all plants and 

animals except those that are adapted for life in water or in saturated soil. 

Wetlands are lands transitional between terrestrial and aquatic systems 

where the water table is usually at or near the surface or the land is covered 

by shallow water. For purposes of this classification wetlands must have one 

or more of the following three attributes: (1) at least periodically, the land 

supports predominantly hydrophytes 28, (2) the substrate is predominantly 

undrained hydric soil 29, and (3) the substrate is non-soil and is saturated 

with water or covered by shallow water at some time during the growing 

season of each year.

The term wetland includes a variety of areas that fall into one of five categories: 

(1) areas with hydrophytes and hydric soils, such as those commonly known as 

marshes, swamps, and bogs; (2) areas without hydrophytes but with hydric soils— 

for example, flats where drastic fluctuation in water level, wave action, turbidity, or 

high concentration of salts may prevent the growth of hydrophytes; (3) areas with 

hydrophytes but non-hydric soils, such as margins of impoundments or excavations 

where hydrophytes have become established but hydric soils have not yet 

developed; (4) areas without soils but with hydrophytes such as the seaweed covered 

portions of rocky shores; and (5) wetlands without soil and without hydrophytes, 

such as gravel beaches or rocky shores without vegetation.

Marine System The marine system consists of the open ocean overlying the continental shelf and 

its associated high energy coastline. Marine habitats are exposed to the waves and 

currents of the open ocean. Salinity exceeds 30 parts per thousand, with little or 

no dilution except outside the mouths of estuaries. Shallow coastal indentations or 

bays without appreciable freshwater inflow and coasts with exposed rocky islands 

that provide the mainland with little or no shelter from wind and waves are also 

considered part of the Marine System because they generally support a typical 

marine biota. 

Estuarine System The estuarine system consists of deepwater tidal habitats and adjacent tidal wetlands 

that are usually semi enclosed by land but have open, partly obstructed, or sporadic 

access to the open ocean and in which ocean water is at least occasionally diluted 

by freshwater runoff from the land. The salinity may be periodically increased 

above that of the open ocean by evaporation. Along some low energy coastlines 

there is appreciable dilution of sea water. Offshore areas with typical estuarine 

plants and animals, such as red mangroves (Rhizophora mangle) and eastern oysters 

(Crassostrea virginica), are also included in the Estuarine System.

27 Adapted from Cowardin et al. 1979.

28 The U.S. Army Corps of Engineers has published the list of plant species that occur in wetlands of the 

United States. See: http://wetland_plants.usace.army.mil.

29 U.S. Department of Agriculture has developed the list of hydric soils for the United States. 

See: http://soils.usda.gov/use/hydric/.
44 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Marine and Estuarine Subsystems

Subtidal The substrate is continuously submerged by marine or estuarine waters

Intertidal The substrate is exposed and flooded by tides. Intertidal includes the splash zone of coastal 

waters.

Palustrine The palustrine (freshwater) system includes all nontidal wetlands dominated by trees, shrubs, 

persistent emergents, emergent mosses or lichens, farmed wetlands, and similar wetlands 

that occur in tidal areas where salinity due to ocean derived salts is below 0.5 parts per 

thousand. It also includes wetlands lacking such vegetation, but with all of the following 

four characteristics: (1) area less than 20 acres; (2) an active wave formed or bedrock 

shoreline features are lacking; (3) water depth in the deepest part of a basin less than 6.6 feet 

at low water; and (4) salinity due to ocean derived salts less than 0.5 parts per thousand. 

Classes

Unconsolidated bottom Unconsolidated bottom includes all wetlands with at least 25 percent cover 

of particles smaller than stones, and a vegetative cover less than 30 percent. 

Examples of unconsolidated substrates are: sand, mud, organic material, cobble 

gravel.

Aquatic Bed Aquatic beds are dominated by plants that grow principally on or below 

the surface of the water for most of the growing season in most years. 

Examples include seagrass beds, pondweeds (Potamogeton spp.), 

wild celery (Vallisneria americana), waterweed (Elodea spp.), and 

duckweed (Lemna spp.).

Rocky Shore Rocky shore includes wetland environments characterized by bedrock, stones, 

or boulders which singly or in combination have an aerial cover of 75 percent or 

more and an aerial vegetative coverage of less than 30 percent.

Unconsolidated Shore Unconsolidated shore includes all wetland habitats having two characteristics: (1) 

unconsolidated substrates with less than 75 percent areal cover of stones, boulders 

or bedrock and; (2) less than 30 percent areal cover of vegetation other than 

pioneering plants.

Emergent Wetland Emergent wetlands are characterized by erect, rooted, herbaceous hydrophytes, 

excluding mosses and lichens. This vegetation is present for most of the growing 

season in most years. These wetlands are usually dominated by perennial plants.

Shrub Wetland Shrub Wetlands include areas dominated by woody vegetation less than 20 feet 

tall. The species include true shrubs, young trees, and trees or shrubs that are 

small or stunted because of environmental conditions.

Forested Wetland Forested Wetlands are characterized by woody vegetation that is 20 feet tall or 

more.

Farmed Wetland Farmed wetlands are wetlands that meet the Cowardin et al. definition where the 

soil surface has been mechanically or physically altered for production of crops, 

but where hydrophytes will become reestablished if farming is discontinued.
Appendix 45

Deepwater Habitat Wetlands and deepwater habitats were defined separately because the term wetland 

does not include deep, permanent water bodies. For conducting status and trends 

studies, Riverine and Lacustrine were considered deepwater habitats. Elements of 

Marine or Estuarine systems can be wetland or deepwater. Palustrine includes only 

wetland habitats.

Deepwater habitats were permanently flooded land lying below the deepwater of 

wetlands. Deepwater habitats include environments where surface water is permanent 

and often deep, so that water, rather than air, is the principal medium in which the 

dominant organisms live, whether or not they were attached to the substrate. As 

in wetlands, the dominant plants were hydrophytes; however, the substrates were 

considered nonsoil because the water is too deep to support emergent vegetation.

Riverine System The riverine system includes deepwater habitats contained in a channel, with the 

exception of habitats with water containing ocean derived salts in excess of 0.5 parts 

per thousand. A channel is an open conduit either naturally or artificially created which 

periodically or continuously contains moving water, or which forms a connecting link 

between two bodies of standing water.

Lacustrine System The lacustrine system includes deepwater habitats with all of the following 

characteristics: (1) situated in a topographic depression or a dammed river channel; 

(2) lacking trees, shrubs, persistent emergents, emergent mosses or lichens with greater 

than 30 percent coverage; (3) total area exceeds 20 acres. 

Uplands

Agriculture30 Agricultural land may be defined broadly as land used primarily for production of 

food and fiber. Agricultural activity is evidenced by distinctive geometric field and 

road patterns on the landscape and the traces produced by livestock or mechanized 

equipment. Examples of agricultural land use include cropland and pasture; orchards, 

groves, vineyards, nurseries, cultivated lands, and ornamental horticultural areas 

including sod farms; confined feeding operations; and other agricultural land including 

livestock feed lots, farmsteads including houses, support structures (silos) and adjacent 

yards, barns, poultry sheds, etc.

Urban Urban land is comprised of areas of intensive use in which much of the land is 

covered by structures (high building density). Urbanized areas are cities and towns that 

provide the goods and services needed to survive by modern day standards through a 

central business district. Services such as banking, medical and legal office buildings, 

supermarkets, and department stores make up the business center of a city. Commercial 

strip developments along main transportation routes, shopping centers, contiguous 

dense residential areas, industrial and commercial complexes, transportation, power 

and communication facilities, city parks, ball fields and golf courses can also be 

included in the urban category.

Silviculture Silviculture includes forested plantations or areas of planted and managed forest stands. 

Planted pines, Christmas tree farms, clear cuts, and other managed forest stands, 

such as hardwood forestry are included in this category. Forested plantations can be 

identified by observing the following remote sensing indicators: 1) trees planted in 

rows or blocks; 2) forested blocks growing with uniform crown heights; and 3) logging 

activity and use patterns.

30Adapted from Anderson et al. 1976.
46 Status and Trends of Wetlands in the Coastal Watersheds of the Conterminous United States 2004 to 2009

Rural Development Rural developments occur in sparse rural and suburban settings outside distinct urban 

cities and towns. They are characterized by non-intensive land use and sparse building 

density. Typically, a rural development is a cross-roads community that has a corner 

gas station and a convenience store which are surrounded by sparse residential housing 

and agriculture. Scattered suburban communities located outside of a major urban 

center can also be included in this category as well as some industrial and commercial 

complexes; isolated transportation, power, and communication facilities; strip mines; 

quarries; and recreational areas such as golf courses, etc. Major highways through rural 

development areas are included in the rural development category.

Other Land Use Other land use is composed of uplands not characterized by the previous categories. 

Typically these lands would include native prairie; unmanaged or non-patterned 

upland forests and scrub lands; and barren land. Lands in transition may also fit into 

this category. Transitional lands are lands in transition from one land use to another. 

They generally occur in large acreage blocks of 40 acres or more and are characterized 

by the lack of any remote sensor information that would enable the interpreter to 

reliably predict future use. The transitional phase occurs when wetlands are drained, 

ditched, filled, leveled, or the vegetation has been removed and the area is temporarily 

bare.

Laughing gulls (Leucophaeus atricilla), Sandwich terns (Thalasseus sandvicensis), and Brown pelicans (Pelecanus occidentalis) on 

Indian Beach, Florida (Nicole Rankin/USFWS)
Front cover photo, top.

Freshwater wetlands of 

coastal Alabama.

Front cover photo, bottom.

Whalehead Beach , Oregon.

Inside cover photo. 

Cave Point, Wisconsin .

(Taylor Trimble)

Blue Crab photo, page 13, by

Phil’s 1stPix , Flickr .

All photos, unless 

otherwise noted, were 

provided courtesy of the 

U.S. Fish and Wildlife 

Service .

Graphic services provided

by the Columbus Publishing 

Service Center, Scientific

Publishing Network, 

U.S. Geological Survey.
U.S. Department of the Interior

Fish and Wildlife Service

http://www.fws.gov

and

National Oceanic and Atmospheric 

Administration

National Marine Fisheries Service

http://www.nmfs.noaa.gov/

October 2013