NRCS GeoHydro—A GIS interface for hydrologic modeling

The US Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) has developed NRCS GeoHydro 9x, a new ArcGIS application, to complement the WinTR–20 application and assist USDA field staff, and other government, private, and foreign organizations. WinTR–20 is a storm event hydrologic model used to evaluate impacts of structural and land treatment measures. NRCS GeoHydro 9x, using geographic information systems (GIS) tools and techniques, performs hydrologic modeling on a drainage area to compute its catchments, drainage points, drainage lines, slope, runoff curve number, longest flow path, time of concentration (Tc), and cross-section details. The application acts as a GIS interface to WinTR–20 by exporting the results of GIS analyses of the drainage area in the input format of WinTR–20. NRCS GeoHydro 9x reinforces the idea that GIS tools and techniques enhance productivity by doing preliminary hydrologic analysis of the drainage area in an objective and accurate manner in a relatively short duration.