Hydrogeomorphic Regions in the Chesapeake Bay Watershed.

This data set was used to compare base-flow and ground-water nitrate loads to
assess the significance of ground-water discharge as a source of nitrate load
to non tidal streams in the Chesapeake Bay watershed.

Generalized lithology (rock type) and physiography based on geologic formations
were used to characterize hydrgeomorphic regions (HGMR) within the Chesapeake
Bay watershed. These HGMRs were used in conjunction with existing data to
assess the significance of ground-water discharge as a source of nitrate load
to non tidal streams in the Chesapeake Bay watershed (Bachman and others,
1998). This work is part of the U.S. Geological Survey's (USGS) Chesapeake Bay
initiative to develop an understanding and provide scientific information for
the restoration of the Chesapeake Bay and its watershed (Phillips and Caughron,
1997).

Any use of trade, product, or firm names is for descriptive purposes only and
does not imply endorsement by the U.S. Geological Survey.

Although this Federal Geographic Data Committee-compliant metadata file is
intended to document the data set in non proprietary form, as well as in
ARC/INFO format, this metadata file may include some ARC/INFO-specific
terminology.

The HGMR data set is the result of combining digital data sets of physiography
and rock type from numerous sources.