HYDROLOGIC PARAMETER-ESTIMATION USING GEOGRAPHIC INFORMATION-SYSTEM

The use of geographic information systems (GIS) can make the task of compiling necessary spatial data and the required hydrologic parameters for modeling watershed runoff relatively easy. Furthermore, recent advances in hydrologic modeling of watersheds have favored the use of physically based methods such as the geomorphological instantaneous unit hydrograph (GIUH) for simulating watershed runoff. A hydrologic model that uses such a procedure is called the watershed hydrology simulation (WAHS) model. The application of this model in hydrology can be facilitated by using a GIS to compile the required data base, composed of various geomorphic and other hydrologic characteristics as spatial-data input. This process is demonstrated in this paper for select watersheds within the Big Sandy River basin in northeastern Kentucky using a GIS software program called ARC/INFO. Although runoff simulation results using the WAHS model did not compare well with the observed data, this study clearly demonstrates the advantages and disadvantages of using a GIS in runoff modeling that require geomorphic and other spatial data bases.