SEPA
                        United States :r;-/->:  -
                        Environmental Protection;
                        Agency     ;  -   '    i'
                             ^Office of Water; ; -;;   r ':  v  '  :
                             Office of "Wetlands,   ^  ;;;'
                             Oceans arid Watersheds (45Q2T)
                          :EFA;843-F-01-062b
                            •September 2001;
                       Do you think all wetlands are the same? Think again. Each
                       wetland differs due to variations in soils, landscape,
                       climate, water regime and chemistry, vegetation, and
                       human disturbance. Below are brief descriptions of the
                       major types of wetlands found in the United States
                       organized into four general categories: marshes, swamps,
                       bogs, and fens.

                               MARSHES are periodically saturated,
                               flooded, or ponded with water and charac-
                       terized by herbaceous (non-woody) vegetation
                       adapted to wet soil conditions. Marshes are
                       	  further characterized as tidal marshes
                                and non-tidal marshes.
  Many vernal pools fill with water in
  fall or spring.
Freshwater marshes like this one in
Sequoia National Park, are dependent
on rainfall, runoff, and seasonal
flooding for their water supplies.
Farmland surrounds these prairie
potholes in Nebraska.
Tidal (coastal) marshes occur along
coastlines and are influenced by tides
and often by freshwater from runoff,
rivers, or ground water. Salt marshes
are the most prevalent types of tidal
marshes and are characterized by salt-
tolerant plants such as smooth cord-
grass, saltgrass, and glasswort. Salt
marshes have one of the highest rates of
  primary productivity associated with
  wetland ecosystems because of the
  inflow of nutrients and organics
  from surface and/or tidal water.
  Tidal freshwater marshes are located
  upstream of estuaries. Tides influence
  water levels but the water is fresh.
  The lack of salt stress allows a
  greater diversity of plants to thrive.
  Cattail, wild rice, pickerelweed,
  and arrowhead are common and
  help support a large and diverse
  range of bird and fish species,
  among other wildlife.

  Nontidal (inland) marshes are
  dominated by herbaceous plants
  and frequently occur in poorly
  drained depressions, floodplains,
  and shallow water areas along the
  edges of lakes and rivers. Major
  regions of the United States that
  support inland marshes include the
  Great Lakes coastal marshes, the
  prairie pothole region, and the
  Florida Everglades.
• Freshwater marshes are characterized by
 periodic or permanent shallow water, little
 or no peat deposition, and mineral soils.
 They typically derive most of their water
 from surface waters, including floodwater
 and runoff, but do receive ground water
 inputs.

> Wet meadows commonly occur in poorly
 drained areas such as shallow lake basins,
 low-lying depressions, and the land
 between shallow marshes and upland areas.
 Precipitation serves as their primary water
 supply, so they are often dry in the summer.

1 Wet prairies are similar to wet meadows
 but remain saturated longer. "Wet prairies
 may receive water from intermittent
 streams as well as ground water and
 precipitation.

 Prairie potholes develop when snowmelt
 and rain fill the pockmarks left on the
 landscape by glaciers. Ground water input
 is also important.

 Playas are small basins that collect rainfall
 and runoff from the surrounding land.
 These low-lying areas are found in the
 Southern High Plains of the United States.

 Vernal pools have either bedrock or a hard
 clay layer in the soil that helps keep water
 in the pool. They are covered by shallow
 water for variable periods from winter to
 spring, but may be completely dry for most
 of the summer and fall.

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Trees found in
swamps are some-
limes buttressed at
the base, which
helps anchor them in
the saturated soils.
Forested swamps serve a
critical role in the water-
shed by reducing the risk
and severity of flooding
to downstream areas.
   SWAMPS are fed primarily by surface water
   inputs and are dominated by trees and
shrubs. Swamps occur in either freshwater or
saltwater floodplains. They are characterized by
very wet soils during the growing season and
standing water during certain times of the year.
Well-known swamps include Georgia's Oke-
fenokee Swamp and Virginia's Great Dismal
Swamp. Swamps are classified as forested,
shrub, or mangrove.

Forested swamps are found in broad
floodplains of the northeast, southeast, and
           south-central United States and
           receive floodwater from nearby
           rivers and streams. Common
           deciduous trees found in these areas
           include bald cypress, water tupelo,
           swamp white oak, and red maple.

           Shrub swamps are similar to
           forested swamps except that
           shrubby species like buttonbush and
           swamp rose dominate.

Mangrove swamps are coastal wetlands char-
acterized by salt-tolerant trees, shrubs, and other
plants growing in brackish to saline tidal waters.
These tropical and subtropical systems have a
North American range that extends from the south-
ern tip of Florida along the Gulf Coast to Texas.

    BOGS are freshwater wetlands characterized
    by spongy peat deposits, a growth of ever-
green trees and shrubs, and a floor covered by a
thick carpet of sphagnum moss. These systems,
whose only water source is rainwater, are
usually found in glaciated areas of the northern
United States. One type of bog, called a
pocosin, is found only in the
Southeastern Coastal Plain.
    FENS are ground
    water-fed peat-
forming wetlands
covered by grasses,
sedges, reeds, and
wildflowers. Willow
and birch are also
common. Fens, like
bogs, tend to occur in
glaciated areas of the
northern United
States.
Bog ecosystems
support
cranberries,
blueberries, and
carnivorous
plants like the
pitcher plant.
                                               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
                                For more information, visit www.epa.gov/owow/wetlands.
   On  the Internet
   EPA's Wetland Home Page contains information and pictures on several
    types of wetlands	www.epa.gov/owow/wetlands/facts/types.html
   Types of Wetlands and Their Roles in the Watershed, part of North Carolina
    State University's WATERSHEDSS 	http://h2osparc.wq.ncsu.edu/info/wetlands/types3.html
   Wetlands of the United States from the USGS Northern Prairie
    Wildlife Research Center	www.npwrc.usgs.gov/resource/1998/uswetlan/types.htm
   Prairie Potholes	www.greatplains.org/resource/1999/ppjv/ppjv.htm

   In Print
   Wetlands, W.J. Mitsch,  and J.G. Gosselmk. 1993. Van Nostrand Reinhold, New York, NY.
   In Search of Swampland: A Wetland Sourcebook and Field Guide. R.W Tiner, 1998. Rutgers University Press, Piscataway, NJ.
   Adopting a Wetland—A Northwest Guide.  S. Yates. 1989.

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