National Water Summary on Wetland Resources
United States Geological Survey Water Supply Paper 2425
STATE SUMMARY HIGHLIGHTS
Following are a few notable facts about the wetlands of the 50 States, the
District of Columbia, Puerto Rico, the Virgin Islands, and several islands
of the Pacific Ocean, as reported in the State summaries:
Wetlands cover about 10 percent of Alabama and range in size from small
areas of less than an acre to the 100,000-acre forested tract in the
Mobile-Tensaw River Delta. Most of the State's forested wetlands are
bottom-land forests in alluvial flood plains. Coastal waters support
extensive salt marshes. Wetland acreage in the area that is now Alabama
has been reduced by about one-half in the last two centuries. Major causes
of wetland loss or alteration have been agricultural and silvicultural
conversions in the interior; dredging on the coast; industrial, commercial,
and residential development; erosion; subsidence; and natural succession of
Alaska has more area covered by wetlands--about 170 million acres--than the
other 49 States combined. More than 70,000 swans, 1 million geese, 12
million ducks, and 100 million shorebirds depend on Alaskan wetlands for
resting, feeding, or nesting. Freshwater Alaskan wetlands include bogs,
fens, tundra, marshes, and meadows; brackish and saltwater wetlands include
flats, beaches, rocky shores, and salt marshes. Most of the State's
freshwater wetlands are peatlands (wetlands that have organic soils), and
cover as many as 110 million acres. Alaska's coastal wetlands are
cooperatively protected and managed by local governments, rural regions,
and the State.
Less than 1 percent of Arizona's landscape has wetlands. Since the late
1800's, streams and wetlands throughout Arizona have been modified or
drained, resulting in the loss of more than one-third of the State's
original wetlands. The most extensive Arizona wetlands are in riparian
zones and include oxbow lakes, marshes, cienegas, and bosques. Nonriparian
wetlands include tinajas, playas, and caldera lakes. Extreme aridity and
seasonally varying precipitation are the climatic characteristics that most
significantly influence wetland formation and distribution in Arizona.
Recreational use of wetlands provides economic benefits to the State.
About 8 percent of Arkansas is wetland. The most extensive areas are
forested wetlands (swamps and bottom-land forests) along major rivers.
Arkansas wetlands, especially those in the Mississippi River Valley, are a
critical component of the series of wetlands along the Mississippi Flyway.
Wetlands in the Cache-Lower White River system have been designated as one
of nine "Wetlands of International Importance" in the United States.
Arkansas has lost more wetland acres than any other inland State; most of
the loss has been due to conversion to farmland. Arkansas has adopted a
program that applies an antidegradation policy to substantial alteration of
water bodies, including adjacent wetlands.
California's wetlands have significant economic and environmental value,
providing benefits such as water-quality maintenance, flood and erosion
attenuation, prevention of saltwater intrusion, and wildlife habitat. The
Sacramento-San Joaquin Delta regularly harbors as much as 15 percent of the
waterfowl on the Pacific Flyway. California has lost as much as 91 percent
of its original wetlands, primarily because of conversion to agriculture.
Flooded rice fields, which are converted wetlands, covered about 658,600
acres in the mid-1980's. Rice farmers, State and university researchers,
and private organizations are cooperatively studying the feasibility of
managing rice fields for migratory waterfowl habitat. Wetland protection
is identified as a goal of The California Environmental Quality Act of
Wetlands cover about 1 million acres of Colorado--1.5 percent of the State's
area. Wetlands occur in all life and climatic zones, from the high
mountains to the arid plains and plateaus. Wetland types in Colorado
include forested wetlands, willow carrs, fens, marshes, alpine snow glades,
and wet and salt meadows. Wetlands are vital to wildlife in the State,
particularly in the arid regions. Colorado's wetland area has decreased by
about one-half in the last two centuries, and losses are continuing due to
a variety of land-development pressures; however, irrigation and changes in
land-use practices have resulted in new wetlands, principally in the San
Luis Valley and near Boulder.
Wetlands cover about 173,000 acres of Connecticut--5 percent of the State's
land surface. Connecticut has lost an estimated one-third to three-fourths
of its original wetlands over the 200-year period between the 1780's and
1980's. Forested wetlands, primarily red maple swamps, are the predominant
wetland type, constituting 54 percent of the State's wetlands. Salt
marshes, tidal flats, and beaches are the primary coastal wetlands.
Wetland protection in Connecticut is carried out at the Federal, State, and
(or) local government level, depending on the type and location of the
Wetlands cover about 17 percent of Delaware. Wetlands in Delaware are
diverse. Extensive estuarine wetlands line Delaware Bay and the Atlantic
Ocean. Delmarva bays, which are seasonally flooded depressions in the
Coastal Plain, contain marsh, shrub, and forest vegetation. More than
one-half of Delaware's wetlands have been converted to nonwetland uses or
otherwise altered since the 1780's. The State Wetlands Act controls
development in tidal wetlands, and a proposed statute would establish a
State-run nontidal-wetlands regulatory program. Delaware has established
its own wetland classification, which has five categories that are based on
a wetland's functions and values.
District of Columbia
The District of Columbia has about 250 acres of wetlands; all are
palustrine or riverine. Most occur along the tidal reaches of the Potomac
and Anacostia Rivers. About 87 percent of the District's wetlands have
been drained or filled since the District was established in the 1790's.
The National Park Service owns and maintains most wetlands in the District
of Columbia. To alter wetlands, permits must be obtained from the U.S.
Army Corps of Engineers and the Department of Consumer and Regulatory
Affairs. Wetland conservation is accomplished on Federal and local levels
and through the activities of private organizations.
Florida has about 11 million acres of wetlands, more than any of the other
47 conterminous States. The abundance of wetlands in Florida is due
primarily to the low, flat terrain and plentiful rainfall. Most of
Florida's wetlands are forested freshwater habitats on stream flood plains,
in small depressions and ponds, and covering wet flatwoods. The
Everglades, in southern Florida, is a large freshwater marsh that once
received surface- and ground-water flows from the Kissimmee River-Lake
Okeechobee Basin but which now depends on water releases from canals and
water-retention areas. Florida has lost nearly one-half of its wetlands,
primarily to agricultural drainage. The State protects wetlands by
regulating development in wetland areas, acquiring wetlands and land
adjacent to wetlands, and requiring local governments to produce long-range
plans for wetland protection.
Georgia has more than 7.7 million acres of wetlands. Georgia's wetlands
are diverse, ranging from mountain seepage areas to estuarine tidal flats.
This diversity is primarily due to the wide variety of landforms present,
each of which can have different geologic and hydrologic characteristics.
The greatest acreages of wetlands are in the coastal plain, where
flood-plain wetlands are most extensive and tidal freshwater swamps and
estuarine marshes meet. Most of Georgia's wetlands are forested freshwater
habitats associated with streams. The Okefenokee Swamp in Georgia, one of
the largest freshwater wetlands in the United States, is a mosaic of
emergent marshes, aquatic beds, forested and scrub-shrub wetlands, and
Wetlands constitute less than 3 percent of the State, but they have had a
major economic effect on Hawaiian society both before and after European
contact. Wetlands are habitats for several species of birds and plants
endemic to the Hawaiian Islands. Wetland formation in Hawaii is influenced
by climate, topography, and geology; wetlands form where local hydrologic
conditions favor water retention near the land surface. Although rainfall
is high in many areas of the islands, steep topography and the high
permeability of the volcanic rock that forms the islands result in rapid
discharge of storm runoff to the ocean as surface-water and ground-water
flow. Coastal wetland losses have been greatest on Oahu, where wetlands
have been drained and filled for resort, industrial, and residential
Most of Idaho's 386,000 acres of wetlands are in flood plains and riparian
areas along streams and other water bodies. Since about 1860, when mining
and farming began in the State, wetland acreage has decreased by 56
percent. The Idaho State Water Plan states that, insofar as is possible,
the State should assume responsibility for wetland management and
protection. Policy plans made by the Idaho Department of Fish and Game for
1991 to 2005 focus land-acquisition efforts on wetland areas where habitat
protection is critical. Many private organizations and groups have
participated in projects involving wetland acquisition and restoration.
Wetlands cover about 3.5 percent of Illinois. The largest acreage of
wetlands is in the bottom-land forests and swamps along the State's major
rivers. Northeastern Illinois also has a large concentration of wetlands.
Illinois has lost as much as 90 percent of its original wetlands over the
last 200 years; most of the losses have been due to drainage for conversion
to agricultural and other uses. The primary State law governing wetlands
is the Interagency Wetland Policy Act of 1989, which sets a goal of no net
loss of wetlands due to projects funded by the State. Wetlands can be
owned and protected by the public as County Forest Preserve Districts.
About 85 percent of Indiana's wetlands have been lost since the 1780's,
primarily because of conversion to agricultural land. The current rate of
wetland loss is about 1 to 3 percent of the remaining wetlands per year.
Most of the wetlands remaining in Indiana, about 813,000 acres, are in the
northeastern part of the State, including extensive wetlands in and near
the Indiana Dunes National Lakeshore. The Department of Natural Resources
is developing a State wetland conservation plan under a grant from the U.S.
Environmental Protection Agency. Several River Basin Commissions are
encouraging or pursuing wetland restoration as a flood-control measure with
an added benefit of recreation potential.
Iowa has diverse wetlands that include prairie-pothole marshes, swamps,
sloughs, bogs, fens, and ponds. Wetlands cover about 1.2 percent of Iowa,
but about 200 years ago more than 11 percent of the State's area was
wetland. Conversion of wetlands to agricultural lands, largely in the
prairie-pothole region, has been the primary cause of wetland loss.
Wetland acreage has been slowly increasing since 1987 as a result of the
Prairie Pothole Joint Venture, a cooperative Federal, State, county, and
private-organization program. The Wetland Reserve Program of the 1990
Food, Agriculture, Conservation, and Trade Act has the potential to add a
substantial number of additional acres.
Kansas has about 435,000 acres of wetlands, which include sandhill pools
along the Arkansas River, playa lakes in western Kansas, freshwater marshes
such as those in Cheyenne Bottoms, and salt marshes such as those in
Quivira National Wildlife Refuge. Kansas wetlands are important to
migrating waterfowl and shorebirds, which depend on the few remaining
wetlands in the Central Flyway. Kansas has lost about one-half its
wetlands during the last 200 years, mostly due to conversion to cropland
and depletion of surface and ground water due to irrigation withdrawals.
Wetland preservation and restoration are being accomplished through
cooperation among Federal and State agencies and private organizations.
Wetlands compose less than 2.5 percent of Kentucky's land area, but they
have considerable environmental, socioeconomic, and esthetic value. Most
Kentucky wetlands lie shoreward of rivers, lakes, and reservoirs and
include cypress swamps, bottom-land hardwood forests, marshes, and ponds.
More than one-half of Kentucky's original wetlands have been lost,
primarily as a conversion to cropland and pastureland; most conversions
have been in western Kentucky. The State fosters protection of wetlands
through a system of registry and dedication agreements with private
entities. Most of Kentucky's wetlands are privately owned.
Wetlands are a major source of income for the people of Louisiana,
providing revenues from harvesting of fish and shellfish, trapping, and
recreation. Most of the State's wetlands are freshwater swamps, but the
area of coastal marsh is substantial: Louisiana's coastal marshes represent
as much as 40 percent of the coastal marshes in the United States.
Wetlands once covered more than one-half of the area that is now Louisiana,
but wetland acreage has declined to less than one-third of the State's land
surface over the last 200 years. The Louisiana Coastal Wetlands
Conservation and Restoration Program implements specific projects to
conserve, enhance, restore, and create coastal wetlands.
Maine's wetlands are diverse, ranging from inland swamps and peatlands to
coastal salt marshes and mud flats. One-fourth of the State is wetland,
and most wetlands are owned by individuals, timber companies, or other
private landowners. Land-use changes have led to wetland losses. Early in
Maine's history, expansion of fishing and farming communities along the
coast resulted in the filling of many coastal wetlands. Wetlands along
inland waterways were converted to agricultural use. Recent losses have
been due to urbanization and other development. Wetland conservation in
Maine is a combined effort by Federal, State, and local governments and
private organizations and landowners.
Maryland has about 591,000 acres of wetlands, one-half of which are tidal
and one-half nontidal. Extensive estuarine wetlands exist on both sides of
the Chesapeake Bay. The Delmarva Peninsula has many wetlands in Delmarva
bays, topographic depressions whose wetness is controlled by the water
table. About 64 percent of Maryland's wetlands have been converted to
nonwetland uses since the 1780's. To obtain permits for altering wetlands
in Maryland, a single State-Federal application is submitted to the
Maryland Department of the Environment. Wetland conservation in Maryland
is accomplished on the Federal, State, and local level and through the
activities of private organizations.
Wetlands cover about 590,000 acres of Massachusetts, about 12 percent of
the State's area. Massachusetts has lost about 28 percent of its original
wetlands since the 1780's. Agricultural and urban expansion have caused
most of the losses. Forested wetlands, primarily red maple swamps,
comprise more than one-half of the State's wetlands; estuarine and marine
wetlands account for about one-fifth. Regulatory functions of wetland
conservation in Massachusetts are performed at the Federal, State, and
local government level, and private organizations are active in land
acquisition and management, research, education, and policy review and
Wetlands cover about 15 percent of Michigan. They provide many benefits,
including flood and erosion attenuation, water-quality maintenance,
recreation, and wildlife habitat. Michigan's wetlands are largely
associated with surface features that are the result of glaciation. Most
Michigan wetlands are vegetated by forest or shrubs, but fresh marsh is
abundant in coastal and inland areas. About one-half of the State's
wetlands have been converted to other uses, primarily agriculture. The
Goemaere-Anderson Wetland Protection Act of 1980 (Public Law 203) and other
State statutes are the basis for Michigan's wetland-conservation program.
The U.S. Environmental Protection Agency has oversight of the State
Minnesota has about 9.5 million acres of wetlands, about one-half the
wetland acreage present in predevelopment times. Most wetland losses have
been due to drainage for agriculture. Minnesota's wetlands are diverse,
ranging from extensive northern peatlands to small prairie potholes.
Minnesota has about 150,000 to 200,000 acres of wild rice beds. The
centerpiece of Minnesota's efforts to protect wetlands is the Wetland
Conservation Act of 1991, which sets a goal of no net wetland loss. The
law fills the gap in wetland protection between larger, deepwater habitats
that are already protected by Minnesota statute and agricultural wetlands
that are addressed by the Federal "Swampbuster" provisions.
Wetlands occupy more than 13 percent of Mississippi. Bottom-land forests,
swamps and freshwater marshes account for most of Mississippi's wetland
acreage; coastal marshes also are extensive. Wetlands in Mississippi are a
key part of the Lower Mississippi Valley Joint Venture program for the
restoration of Mississippi Flyway waterfowl populations. Nearly
three-fifths of the State's wetlands have been converted to nonwetland
uses, primarily agriculture. Mississippi wetlands have been and continue
to be a source of timber, and the cleared, fertile lands have become
productive farmland. The Natural Heritage Program identifies and
inventories priority wetlands.
Missouri's wetlands occupy 643,000 acres, about 1.4 percent of the State's
area. Swamps and other forested wetlands, marshes and fens, and shrub
swamps constitute most of the wetland acreage. Missouri's location on the
Mississippi Flyway makes the State a favored wintering area for hundreds of
thousands of waterfowl and other birds, including bald eagles. Missouri
has lost as much as 4.2 million acres (87 percent) of its original
wetlands. Most wetland loss has been due to agricultural conversions,
urban development, and flood-control measures. The State has developed a
wetland-management plan to guide its efforts in the restoration and
management of wetlands until the year 2000.
Wetlands cover only a small part of Montana, but their ecological and
economic importance far outweighs their relative size. About 27 percent of
the wetlands present before 1800 have been converted to other land uses,
primarily cropland. Losses to cropland have been particularly great in
north-central and eastern Montana, an area that is part of the Nation's
most valuable waterfowl production area, the prairie pothole region of the
northern Great Plains. Montana has no comprehensive wetland-protection
program; however, the Water Quality Bureau of the Montana Department of
Health and Environmental Sciences is developing enforceable water-quality
and biological standards specific to Montana wetlands.
Nebraska has three wetland complexes recognized as being of international
importance as migrational and breeding habitat for waterfowl and nongame
birds: the Rainwater Basin wetlands in south-central and southeastern
Nebraska, the Big Bend reach of the Platte River (directly north of the
Rainwater Basin), and the Sandhills wetlands in north-central and
northwestern Nebraska. Nebraska has lost about 1 million acres of wetlands
in the last 200 years--about 35 percent of the State's original wetland
acreage. Conversion to agricultural use was the primary cause for most of
the losses, but urbanization, reservoir construction, highway construction,
and other activities also contributed.
Wetlands cover less than 1 percent of Nevada but are some of the most
economically and ecologically valuable lands in the State. Benefits of
wetlands include flood attenuation, bank stabilization, water-quality
improvement, and fish and wildlife habitat. Desert wetlands include
marshes in playa lakes, nonvegetated playas, and riparian wetlands;
mountain wetlands include fens and other wetlands that form in small
glacial lakes. More than one-half of Nevada's original wetlands have been
lost, primarily due to conversion of wetlands to cropland and diversion of
water for agricultural and urban use; many others have been seriously
degraded by human activities. Some wetlands have been created by mine
dewatering and sewage treatment.
Wetlands occupy as much as 10 percent of New Hampshire and are an integral
part of its natural resources. Swamps and peatlands comprise most of the
State's wetlands. Many wetlands have been converted to nonwetland uses
such as crop or pastureland. Others have been altered or degraded by
urbanization, peat mining, timber harvesting, road building, all-terrain
vehicle use, and other causes. New Hampshire regulates wetlands primarily
through State law and the rules of the Wetlands Board; local conservation
commissions have an advisory role in local wetland protection. During 1987
to 1993, the State acquired diverse wetlands by purchase and donation or
protected wetlands through conservation easements.
New Jersey has about 916,000 acres of wetlands, most of which are in the
coastal plain. Forested wetlands are the most common and widely
distributed wetlands in the State. Salt marshes are the most common
wetlands in coastal areas. Wetlands are ecologically and economically
valuable to the State. Cranberry growing is a significant industry in New
Jersey; more than 3,000 acres of cranberry bog wetlands were under private
management in 1992. Between the 1780's and 1980's, New Jersey lost about
39 percent of its wetlands. Wetlands have been drained primarily for crop
production and pasturage and filled for housing, transportation,
industrialization, and landfills.
Wetlands cover about 482,000 acres (0.6 percent) of New Mexico; most are in
the eastern and northern areas of the State. New Mexico's wetlands include
forested wetlands, bottom-land shrublands, marshes, fens, alpine snow
glades, wet and salt meadows, shallow ponds, and playa lakes. Riparian
wetlands and playa lakes are especially valuable to migratory waterfowl and
wading birds. New Mexico has lost about one-third of its wetlands, mostly
due to agricultural conversion, diversion of water to irrigation,
overgrazing, and urbanization. Other causes of loss or degradation have
been mining, clear cutting, road construction, streamflow regulation, and
invasion by nonnative plants.
New York has about 2.4 million acres of wetlands. One-half of the 160
species identified as endangered or threatened by the Department of
Environmental Conservation are wetland dependent. Counties in the
Adirondack Mountains and those south and east of Lake Ontario have the
largest percentages of wetland area; counties that make up New York City
and Long Island, along the border with Pennsylvania, and in the Catskills
have the smallest percentages. From the 1780's to 1980's, about 60 percent
of New York's wetland area was lost, primarily because of conversion to
agriculture and other land uses. Counties may facilitate wetland
acquisition through the funding of bond acts.
About 5.7 million acres of North Carolina--17 percent of the State--is
wetland. The Coastal Plain contains 95 percent of the State's wetlands.
Before colonization by Europeans, North Carolina had about 11 million acres
of wetlands. Nearly one-third of the wetland alterations in the Coastal
Plain have occurred since the 1950's; most have resulted from conversion to
managed forests and agriculture. The Roanoke River flood plain has one of
the largest intact and least disturbed bottom-land hardwood forests in the
mid-Atlantic region. About 70 percent of the rare and endangered plants
and animals in the State are wetland dependent.
Wetlands once covered about 4.9 million acres of North Dakota--11 percent of
the State. By the 1980's, the acreage had decreased to about 2.7 million
acres, a loss of about 45 percent. Most of the losses have been caused by
drainage for agricultural development. The rate of agricultural
conversions in the future will likely depend on crop prices and other
economic factors. Most of North Dakota's wetlands are prairie potholes,
which provide nesting and feeding habitat for migratory waterfowl and
wading birds. About one-half the Nation's duck population originates in
the Prairie Pothole Region of North Dakota and other prairie States.
Ohio's wetlands cover about 1.8 percent of the State. Swamps, wet
prairies, coastal and embayment marshes, peatlands, and wetlands along
stream margins and backwaters are the most common Ohio wetlands. Wetland
area in Ohio has declined by 90 percent during the last 200 years, from
about 5,000,000 acres to about 483,000 acres. Drainage of wetlands for
agriculture has been the primary cause of wetland loss, but recreational
use, fluctuating water levels, urban development, mining, logging, and fire
also have contributed. Ohio designates all wetlands as State Resource
Waters. As such, wetland water quality is protected from degradation that
may interfere with designated uses.
Wetlands cover about 950,000 acres (2 percent) of Oklahoma. Wetlands in
Oklahoma include bottom-land hardwood forests and swamps; marshes and wet
meadows; aquatic-bed wetlands characterized by submersed or floating plants
in ponds, lakes, rivers, and sloughs; and sparsely vegetated wetlands such
as intermittently flooded playa lakes. Most forested wetlands are in
eastern Oklahoma, where precipitation is highest and evaporation lowest.
Riparian wetlands and playa lakes in drier western Oklahoma are especially
valuable to wildlife. Nearly two-thirds of Oklahoma's original wetlands
have been lost as a result of agricultural conversions, channelization,
impoundment, streamflow regulation, and other causes.
Wetlands are economically and ecologically valuable to Oregon and can be
found statewide. Oregon had nearly 1.4 million acres of wetlands as of the
mid-1980's, a decline of more than one-third over the previous 200 years.
Most of the losses were due to conversion to agricultural uses, primarily
in the Willamette River Valley and Upper Klamath Basin. To improve the
effectiveness and efficiency of Oregon's efforts to conserve, restore, and
protect wetlands, the State has developed the Wetland Conservation
Strategy. The strategy is based on the recommendations of advisory
committees representing Federal, State, and local agencies and interest
About 1.4 percent (404,000 acres) of Pennsylvania is covered by wetlands.
Deciduous and forested wetlands are the most common types, followed by open
water, marshes, shrub wetlands, and others. Wetlands are most densely
distributed in the glaciated northwestern and northeastern parts of the
State. Wetland area in Pennsylvania has decreased by more than one-half in
the last 200 years. The primary causes of wetland loss or degradation have
been conversion to cropland, channelization, forestry, mining, urban
development, and the construction of ponds and impoundments. About 50
private conservancy organizations in the State work to protect and preserve
natural lands, including wetlands, on a local level.
Wetlands in Puerto Rico are diverse, ranging from interior montane wetlands
of the rain forest to intertidal mangrove swamps along the coast. Puerto
Rico's wetlands are valuable natural resources that provide habitat for
wildlife and a water supply for several large cities. Nearly all of Puerto
Rico's wetlands have been modified by man--historically for sugar cane
agriculture and more recently for housing development, transportation,
tourist facilities, and other types of development. Wetland restoration
efforts are underway at several locations throughout Puerto Rico; an
example is the freshwater wetlands of Laguna Cartagena, once one of the
most important waterfowl habitats on the island.
Wetlands cover about 65,000 acres of Rhode Island, about 10 percent of the
State's area. Forested wetlands, primarily red maple swamps, are the most
abundant wetland type and account for nearly three-quarters of the State's
wetlands. Once more common in Rhode Island, Atlantic white cedar wetlands
are now found mostly in the southwestern part of the State. Wetlands are
regulated primarily at the State-government level in Rhode Island;
different agencies regulate coastal and freshwater wetlands. Local
land-use controls are an additional wetland-protection measure. Many of
Rhode Island's natural resources have been acquired and protected through
cooperative efforts of private and public entities.
Nearly one-quarter of South Carolina is wetland--about 4.6 million acres.
South Carolina's wetlands provide flood attenuation, erosion control,
water-quality maintenance, recreational opportunities, and fish and
wildlife habitat. South Carolina wetlands are important wintering areas
for migratory waterfowl on the Atlantic Flyway. Wetlands in the State
include wet pine flatwoods, pocosins, Carolina bays, beaver ponds,
bottom-land forests, swamps, fresh and salt marshes, and tidal flats.
About 80 percent of the wetlands are freshwater and forested. Wetland
acreage in South Carolina has declined by more than one-quarter since the
late 1700's, primarily as a result of human activities.
Wetlands occupy about 1.8 million acres (3.6 percent) of South Dakota.
These wetlands are of great economic and esthetic value because they
provide important habitat for wildlife (especially migratory waterfowl),
hydrologic benefits that include water retention and flood attenuation, and
numerous recreational opportunities. By far the most common wetland type
in South Dakota is the prairie pothole, which occurs in glaciated eastern
South Dakota. Wetland area in South Dakota has decreased by about 35
percent during the last 200 years--from about 2.7 million to about 1.8
million acres. Agricultural conversions, notably in the prairie pothole
region, have accounted for most wetland losses.
Estimates of Tennessee's wetland area range from 640,000 to 1,400,000
acres. Although wetlands constitute a small percentage of Tennessee, they
are ecologically and economically valuable to the State. Bottom-land
forests are the most common Tennessee wetlands; they are most abundant in
the flood plains of rivers in the western part of the State. Nearly
three-fifths of Tennessee's original wetlands have been lost; major causes
of loss or degradation in Tennessee have included agricultural conversions,
logging, reservoir construction, channelization, sedimentation, and
urbanization. The Tennessee Wetlands Acquisition Act of 1986 authorizes
the acquisition of wetlands by use of real estate transfer taxes.
Wetlands cover about 7.6 million acres of Texas, 4.4 percent of the State's
area. The most extensive wetlands are the bottom-land hardwood forests and
swamps of East Texas; the marshes, swamps, and tidal flats of the coast;
and the playa lakes of the High Plains. Wetlands provide flood
attenuation, bank stabilization, water-quality maintenance, fish and
wildlife habitat, and opportunities for hunting, fishing, and other
recreational activities. Commercial fisheries benefit directly from
coastal wetlands. Texas has lost about one-half of its original wetlands
as a result of agricultural conversions, overgrazing, urbanization,
channelization, water-table declines, construction of navigation canals,
and other causes.
Wetlands cover only a small part of Utah but provide critical aquatic
habitat in an arid environment as well as economic and other benefits.
Utah wetlands include the shallows of small lakes, reservoirs, ponds, and
streams; riparian wetlands; marshes and wet meadows; mud and salt flats;
and playas. The largest wetlands in the State surround Great Salt Lake.
Because of the importance of Great Salt Lake and its associated wetlands to
migratory waterfowl and shorebirds, in 1991 the lake was designated a
Hemispheric Reserve in the Western Hemisphere Shorebird Reserve Network.
Streamflow regulation and agricultural, residential, industrial, and
ski-area development have resulted in widespread wetland losses.
Estimates of the area covered by wetlands in Vermont range from 4 to 6
percent of the State's total area. The largest wetlands are in the valleys
of the northeast and in river flood plains and deltas in the Lake Champlain
Valley. Vermont's wetlands provide flood and erosion control,
water-quality maintenance, timber, and recreational opportunities. As much
as 35 percent of Vermont's wetlands have been lost; major causes have been
conversion to agriculture and residential and recreational development.
The State is undertaking the Vermont Wetlands Conservation Strategy, a
comprehensive review of current wetland conservation programs that will
recommend actions to improve wetland conservation in Vermont.
U.S. Virgin Islands
Wetlands in the U.S. Virgin Islands comprise about 3 percent of the land
surface. Wetlands are habitat for fish, shellfish, and birds, including
endangered species such as the peregrine falcon and brown pelican.
Freshwater is scarce in the islands, and wetlands there are mainly
estuarine and marine types such as salt ponds, mangrove forests, sea grass
beds, and coral reefs. Shoreline wetlands are vulnerable to destruction
from construction of tourist facilities and water-dependent developments
like marinas and to degradation by sedimentation and septic tank leachate.
The Territorial Legislature adopted the Indigenous and Endangered Species
Act of 1990, which establishes a policy of "no net loss of wetlands" to the
maximum extent possible.
Virginia has about 1 million acres of wetlands; one-quarter are tidal and
three-quarters are nontidal. Forested wetlands (swamps) are the most
common wetlands in the State. Both shores of the Chesapeake Bay have
extensive estuarine wetlands. Conversion to nonwetland uses (agricultural,
urban, industrial, and recreational), channelization and ditching, and
other causes have resulted in the loss of about 42 percent of Virginia's
wetlands since the 1780's. Development in wetlands is regulated in part by
means of the Virginia Water Protection Permit. Local governments may adopt
prescribed zoning ordinances and form citizen wetland boards to regulate
their own tidal wetlands; the State retains an oversight and appellate
Wetlands cover only about 2 percent (939,000 acres) of Washington, but they
benefit the State both ecologically and economically. Wetlands are nursery
and feeding areas for anadromous fish such as salmon and steelhead trout.
About 75 percent of the State's wetlands contain freshwater and include
forested and shrub swamps, bogs, fens, marshes, wet prairies and meadows,
vernal pools, and playas. About 25 percent are estuarine or marine and
include marshes, tidal flats, beaches, and rocky shores. Estimates of
wetland loss in Washington range from 20 to 50 percent; causes of loss or
degradation include agricultural conversion, urban expansion, siting of
ports and industries, logging, and invasion of nonnative plants and
Wetlands constitute less than 1 percent of West Virginia's surface area but
contribute significantly to the State's economic development and ecological
diversity. Common West Virginia wetlands include swamps, peat bogs, marl
wetlands, marshes, wet meadows, and ponds. The Canaan Valley and Meadow
River wetlands together contain about 14 percent of the State's wetlands.
The Canaan Valley wetland complex is the largest in the central Appalachian
Mountains. West Virginia has lost about one-fourth of its original
wetlands; primary causes have been agricultural conversions,
channelization, pond and reservoir construction, and urbanization. Some
wetlands have been created as a result of beaver activity.
Western Pacific Islands
Most of the wetlands in the Mariana, Samoan, Caroline, and Marshall Islands
(referred to as the Western Pacific Islands in this report) are in coastal
areas. Wetlands on the islands include mangrove swamps, marshes, and coral
reefs. Wetlands are of economic importance on many islands because the
staple food, taro, is grown in converted or constructed wetlands. On the
larger islands, wetlands are important wildlife habitat. Available trend
information indicates that on many islands there has been wetland loss or
degradation due to agricultural conversion, urban expansion, or firewood
cutting. Wetland activities on islands under United States jurisdiction
are subject to Federal regulation.
Wetlands cover more than 5 million acres (15 percent) of Wisconsin. Common
wetlands include swamps and marshes in southern Wisconsin and peatlands in
northern Wisconsin. Wetlands are most numerous in glaciated parts of the
State; the unglaciated "driftless" section of southwestern Wisconsin has
few wetlands, except in stream valleys filled with unconsolidated outwash
and alluvium. Wetland acreage has decreased by nearly one-half over the
last 200 years, primarily owing to agricultural development. In 1991 the
State became the first to adopt water-quality standards for wetlands; the
standards allow the State to control wetland development under section 401
of the Clean Water Act.
Wetlands cover about 1.25 million acres (2 percent) of Wyoming and are the
most diverse ecosystems in the State's semiarid environment. The Laramie
Plain Lakes wetland complex is home to the Wyoming toad, an endangered
species. Trend information indicates that wetland acreage in Wyoming has
decreased over time, primarily due to agricultural and urban development.
However, agricultural diversions, whose original purpose was to flush salts
and increase hay-meadow production, have enhanced wetlands along the Bear
River; the Bear River wetland is one of the most productive and diverse
bird habitats in Wyoming. The Wyoming Wetlands Act is the basis for
wetland program development by the State.
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