United States
Environmental Protection
Agency
Office of Water
Office of Wetlands,
Oceans and Watersheds (4502T)
EPA 843-F-01 -002d
September 2001

Destroying or
degrading
wetlands can
lead to serious
consequences,
such as
increased
flooding,
extinction of
species, and
decline in water
quality. We can
avoid these
consequences
by maintaining
the valuable
wetlands we
still have and
restoring lost or
impaired
wetlands where
possible.
What Is the Status of Our Nation's Wetlands?
More than 220 million acres of wetlands are thought to
have existed in the lower 48 states in the 1600s. Since
then extensive losses have occurred, and more than
half of our original wetlands have been drained and
converted to other uses. The mid-1950s to the mid-
1970s ivere a time of major national wetland loss.
Since then the rate of loss has slowed.
The National Audubon Society notes that
bird populations continue to decrease as
wetlands are destroyed. In the past 15 years
alone, the continental duck breeding popu-
lation fell from 45 million to 31 million birds,
a decline of 31 percent. The number of birds
migrating over the Gulf of Mexico, which
rely on coastal wetlands as staging areas
(especially in Louisiana and Mississippi), has
decreased by one-half since the mid-1960s.
Approximately 100 million wetland acres
remain in the 48 contiguous states, but they
continue to be lost
Percentage of Wetlands
Acreage Lost, 1780s-l 980s
Twenty-two states have lost at
least 50 percent of their
original wetlands. Since the
1970s, the most extensive
losses have been in Louisiana,
Mississippi, Arkansas, Florida,
South Carolina, and North
Carolina.
Source: Wetlands,
2nl edition,
Van Nostrand and
Reinholdt, 1993.
at a rate of about
60,000 acres
annually. Draining
wetlands for
agricultural
purposes is
significant, but
declining, while
development
pressure is
emerging as the
largest cause of
wetland loss.
Unfortunately, many remaining wetlands are
in poor condition and many created wetlands
fail to replace the diverse plant and animal
communities of those destroyed.
When a wetland functions properly, it
provides water quality protection, fish and
wildlife habitat, natural floodwater storage,
and reduction in the erosive potential of
surface water. A degraded wetland is less able
to effectively perform these functions. For
this reason, wetland degradation is as big a
problem as outright wetland loss, though
often more difficult to identify and quantify.
What Is Adversely Affecting Our
Wetlands?
Human activities cause wetland degradation
and loss by changing water quality, quantity,
and flow rates; increasing pollutant inputs; and
changing species composition as a result of
disturbance and the introduction of nonnative
species. Common human activities that cause
degradation include the following:
Hydrologic Alterations. Awetland's character-
istics evolve when hydrologic conditions cause
the water table to saturate or inundate the soil for
a certain amount of time each year. Any change
in hydrology can significantly alter the soil chem-
istry and plant and animal communities. Common
hydrologic alterations in wetland areas include:
•	Deposition of fill material for development.
•	Drainage for development, farming, and
mosquito control.
•	Dredging and stream channelization for
navigation, development, and flood control.
•	Diking and damming to form ponds and
lakes.
•	Diversion of flow to or from wetlands.
•	Addition of impervious surfaces in the
watershed, thereby increasing water and
pollutant runoff into wetlands.
Pollution Inputs. Although wetlands are capable
of absorbing pollutants from the surface water,
there is a limit to their capacity to do so. The
primary pollutants causing wet-land degradation
are sediment, fertilizer, human sewage, animal
waste, road salts, pesticides, heavy metals, and

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selenium. Pollutants can originate from many
sources, including:
•	Runoff from urban, agricultural,
silvicultural, and mining areas.
•	Air pollution from cars, factories, and
power plants.
•	Old landfills and dumps that leak toxic
substances.
•	Marinas, where boats increase turbidity and
release pollutants.
Vegetation Damage. Wetland plants are
susceptible to degradation if subjected to
hydrological changes and pollution inputs.
Other activities that can impair wetland
vegetation include:
•	Grazing by domestic animals.
•	Introduction of nonnative plants that
compete with natives.
•	Removal of vegetation for peat mining.
What Can You Do?
Nearly 75 percent of all wetlands are privately
owned, making it imperative that the public
participate in wetland management and
protection. Here are some things you can do:
•	Conserve and restore wetlands on your
property.
•	Support local wetlands and watershed
protection initiatives by donating
materials, time, or money.
Pollutants such as
sediment, nutrients,
pesticides, and heavy
metals degrade wetlands
and water quality across
the country.
Work with your local municipalities and
state to develop laws and ordinances that
protect and restore wetlands.
Purchase federal duck stamps from your
local post office to support wetland acquisition.
Encourage neighbors and developers
to protect the function and value of
wetlands in your watershed.
Avoid wetland alteration or
degradation during project construction.
Maintain wetlands and adjacent buffer
strips as open space.
Reduce the amount of fertilizers,
herbicides, and pesticides applied to
lawns and gardens.
Participate in the Clean Water Act Section
program and state regulatory programs
by reviewing public notices and
commenting on applications.
404
American Avocet
rsmsi
A Global Overview of Wetland Loss and Degradation. Available on The Ramsar Convention on Wetlands' web site at
www.ramsar.org/about_wetland_loss.htm.
Wetland Issues. Available on-line at www.ncseonline.org/NLE/CRSreports/Wetlands/wet-5.cfm.
Wetlands Loss and Degradation. Visit the North Carolina State University Water Quality Group's on-line informational
database, WATERSHEDSS, at h2osparc.wq.ncsu.edu/info/wetlands/wetloss.html.
Wetlands and Agriculture: Private Interests and Public Benefits, Ralph E. Heimlich et al. USDA-ERS Report No. 765.
Available on-line atwww.ers.usda.gov/publications/aer765.
For more information, visit www.epa.gov/owow/wetlands.
The Wetland Fact Sheet Series
Wetlands Overview
Types of Wetlands
Functions & Values of Wetlands
Threats to Wetlands
Wetland Restoration
Funding Wetland Projects
Wetland Monitoring & Assessment
Sustainable Communities
Volunteering for Wetlands
Teaching about Wetlands

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