Agnps Watershed Modeling with Gis Databases

Geospatial databases built with geographic information systems served as primary sources of input data to the Agricultural NonPoint Source pollution model of watershed hydrology. Elevation, land cover, and soil data for four watersheds are the base from which we extracted the 22 input parameters required by the Agricultural NonPoint Source model. The study demonstrates the utility of employing geospatial databases as sources in watershed modeling to investigate the improved accuracy of the water-quality model results, and it shows examples of the automatic extraction of model input parameters from these databases. The study examines the implications of the results for modelers using this model in four watersheds: two in Georgia, and one each in Indiana and Washington. To demonstrate the development and practical utility of the user-friendly interface, a tool was created for generating input parameters, executing the pollution model, and analyzing model output. This tool uses object-oriented programming and macro languages to manipulate the raster databases. This investigation demonstrates new methods of automatically extracting the requisite input parameters for the Agricultural NonPoint Source pollution model from geographic information systems databases.