Geographic Information Systems
Report on Nine Aggregate Ecoregions
The strategic plan of the U.S. EPA calls for a survey and report on
the condition of the Nation’s lakes, rivers and streams. GLEC is the
lead contractor for this important multi-year effort. In support of this
project, EPA asked GLEC to construct nine unique ecoregions for
the conterminous U.S. and then analyze and report on each ecoregion’s
physiographic, ecological, and anthropogenic characteristics.
GLEC’s GIS specialists combined and modified existing detailed
ecoregions into the nine new ecoregions, and then overlaid pertinent
spatial data such as hydrography, climate, habitat, land cover,
census data, pollution, and industrial and agricultural activity. Spatial
analysis techniques were then employed to extract statistics and
characteristics of each ecoregion.
Figure 25. Ecoregions surveyed for the WSA (U.S. EPA/WSA).
Click image to enlarge.
map provides a
for the probability-based water
quality survey data
the field sampling
efforts. The project
in order to relate
the natural features, natural history, ecology, and human impacts
within each ecoregion. The nine aggregate ecoregion map has been
published in EPA’s Wadeable Streams Assessment report and will
be included in a comprehensive report to the U.S. Congress on the
health of the nation’s waters.
In addition to the GIS components of the survey of the nation’s
waters, GLEC is responsible for study design, logistics support,
field crew training and field sampling support for assessing habitats,
chemistry, and macroinvertebrate health.