1987 Wetland Delineation Manual - The Wetlands Regulation Center

Wetland Delination Manual, 1987 32
d. Stream and tidal gage data. These documents provide records of tidal and stream flow
events. They are available from either the USGS or CE District office.
e. Environmental impact assessments (EIAs), environmental impact statements (EISs), general
design memora da (GDM), and other similar publications. These documents may be available
from Federal agencies for an area that includes the project area. They may contain some
indication of the location and characteristics of wetlands consistent with the required criteria
(vegetation, soils, and hydrology), and often contain flood frequency and duration data.
f. Documents and maps from State, county, or local governments. Regional maps that
characterize certain areas (e.g., potholes, coastal areas, or basins) may be helpful because they
indicate the type and character of wetlands.
g. Remote sensing. Remote sensing is one of the most useful information sources available for
wetland identification and delineation. Recent aerial photography, particularly color infrared,
provides a detailed view of an area; thus, recent land use and other features (e.g. general type
and areal extent of plant communities and degree of inundation of the area when the
photography was taken) can be determined. The multiagency cooperative National High
Altitude Aerial Photography Program (HAP) has 1:59,000-scale color infrared photography for
approximately 85 percent (December 1985) of the coterminous United States from 1980 to
1985. This photography has excellent resolution and can be ordered enlarged to 1:24,000 scale
from USGS. Satellite images provide similar information as aerial photography, although the
much smaller scale makes observation of detail more difficult without sophisticated equipment
and extensive training. Satellite images provide more recent coverage than aerial photography
(usually at 18-day intervals). Individual satellite images are more expensive than aerial
photography, but are not as expensive as having an area flown and photographed at low
altitudes. However, better resolution imagery is now available with remote sensing equipment
mounted on fixed-wing aircraft.
h. Local individuals and experts. Individuals having personal knowledge of an area may
sometimes provide a reliable and readily available source of information about the area,
particularly information on the wetness of the area.
i. USGS land use and land cover maps. Maps created by USGS using remotely sensed data
and a geographical information system provide a systematic and comprehensive collection and
analysis of land use and land cover on a national basis. Maps at a scale of 1:250,000 are
available as overlays that show land use and land cover according to nine basic levels. One
level is wetlands (as determined by the FWS), which is further subdivided into forested and
nonforested areas. Five other sets of maps show political units, hydrologic units, census
subdivisions of counties, Federal land ownership, and State land ownership. These maps can
be obtained from any USGS mapping center.
25 February 1997 Environmental Techncal Services Co. 834 Castle Ridge Rd Austin, Texas 78746