Integration of the soil and water assessment tool with the Information System in watersheds modeling

Geographic Information Systems have become indispensable tools for watershed-scale hydrologic analysis and modeling. The integrative capabilities of GIS can emulate real-world complexity, facilitating interdisciplinary research and communication. Landsat Thermal Mapper raster images represent topography, land use, land cover, as well as spatial data of surface and ground water hydrology, weather, and soils types are all integrated in GIS themes such as views, tables, charts, and layouts. GIS is being used in data visualization, processing, and management. This paper presents a case study on the integration between the Geographical Resources and Assessment Support System (GRASS) and the distributed parameter and physical process watershed model, Soil and Water Assessment Tool (SWAT) for the management of land practices. This integration proved to be effective and efficient for input data extraction and management for simulating the baseline conditions as well as other scenarios. SWAT is capable of continuous time simulation and flexible domain delineation. The spatial distribution of SWAT output results was successfully presented by using Geomedia-Intergraph software. By using SWAT-Geomedia integration, areas under sever water quality problems could be identified. Sediment and nutrients loads were studied in order to determine a better management of surface water resources in large agricultural watershed.