Submitted to: Transactions in Geographic Information Systems
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/15/2003
Publication Date: 1/15/2004
Citation: Diluzio, M., Arnold, J.G. 2004. A GIS-coupled hydrological model system for the watershed assessment of agricultural nonpoint and point sources of pollution. Transactions in Geographic Information Systems (GIS). 8(1):113-136. Interpretive Summary: Decision-makers use watershed models to determine the impact of land management on water quality and supply within a watershed or river basin. Watershed models are critical tools used in national conservation assessments by NRCS (Natural Resources Conservation Service) and watershed assessments by EPA (Environmental Protection Agency). Watershed models require significant input data including weather, topography, soils, land use and management. Assembling this data can be expensive and time consuming. In this study a GIS (geographic information system) interface was developed to automate development of spatial input data, decreasing the time and money required to run watershed models. The linked watershed/GIS model developed in this study is being used around the world for water resource assessments.
Technical Abstract: This paper introduces AVSWAT, a GIS based hydrological system linking the Soil and Water Assessment Tool (SWAT) water quality model and the ArcView Geographic Information System software. The main purpose if AVSWAT is the combined assessment of nonpoint and point pollution loading at the watershed scale. The GIS component of the system, in addition to the traditional functions of the data acquisition, storage, organization and display, implements advanced analytical methods with enhanced flexibility to improve the hydrological characterization of a study watershed. Intuitive user friendly graphic interfaces, also part of the GIS component, have been developed to provide an efficient interaction with the model and the associated parameter databases, and ultimately to simplify water quality assessments, while maintaining and increasing their reliability. This is also supported by SWAT, the core of the system, a complex, conceptual, hydrologic, continuous model with spatially explicit parameterization, building upon the United State Department of Agriculture (USDA) modeling experience. A step-by-step example application for a watershed in Central Texas is also included to verify the capability and illustrate some of the characteristics of the system, which has been adopted by many users around the world.