From: kiran (Kiran R)
Message-Id: <199711241323.NAA17129@ces.iisc.ac.in>
X-URL: http://www.epa.gov/emap/html/dataI/wetlands/tOtherPlants.html
Subject: Wetland Map - EMAP :http://www.epa.gov/emap.html-dataI-wetlands-tOtherPlants.html
Status: R


   United States Environmental Protection Agency EMAP Logo
   Wetlands
   
   Wetlands Map EMAP used the U.S. Fish and Wildlife Service's National
   Wetlands Inventory definition of wetlands: Wetlands are lands
   transitional between terrestrial and aquatic systems where the water
   table is usually at or near the surface or where shallow water covers
   the land and where at least one of the following attributes holds: 1)
   the land predominantly supports aquatic plants at least periodically;
   2) undrained hydric soils are the predominant substrate; and 3) at
   some time during the growing season, the substrate is saturated with
   water or covered by shallow water. Wetlands are characterized and
   distinguished by soil, hydrology, salinity, vegetation, and other
   factors. The variety of common names for wetlands--marshes, swamps,
   potholes, bogs, fens, and pocosins--attest to the diversity of wetland
   types. In wetlands, water saturation is the dominant factor
   determining the nature of the soil and the types of plant and animal
   communities living in the soil and on its surface.
   
   The target population for wetland sampling included all vegetated
   emergent wetlands in the United States greater than one-half hectare
   (a little larger than 1 acre) (Figure Above). The EMAP grid had to be
   adequate to determine regional and national wetlands condition, define
   trends, and estimate the extent of common wetland resources. Regional
   estimates of the rare wetland resources, however, did require a
   sampling frame with finer resolution. These sampling units were
   derived by increasing (augmenting) the EMAP grid density or by listing
   all the rare wetlands in a region and sampling from this list frame.
   
   EMAP's Wetlands Group cooperated with the Fish and Wildlife Service
   National Wetlands Inventory to design and implement this EMAP
   component.
   
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                                                    Last Updated 09/03/97
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