HYDROLOGIC SIMULATION OF RUNOFF USING SWAT MODEL

Abstract

Water, the single most important requirement for life, is probably the only natural resource to touch all aspects of human civilizations- from agriculture and industrial development to the cultural and religious values embedded in society. As the fresh water is becoming a scarce resource, its quantitative assessment gaining importance day by day. Thus, importance of rainfall-runoff modeling can hardly be over-emphasized. Among the multitude of rainfall-runoff models available in literature, the Soil and Water Assessment Tool (SWAT) has gained popularity in recent past. This is a distributed watershed model developed by Agricultural Research Service of United States Department of Agriculture to predict the impact of land management practices on water, sediment and agricultural chemical yields in complex watersheds. It is a comprehensive model which requires a significant amount of data and parameters for simulation of runoff and loadings mainly from rural catchments. To setup the SWAT model, a watershed is subdivided into a number of sub watersheds. These watersheds are further subdivided into Hydrologic Response Units (HRU) which are units of unique intersection of land use and soil. Watershed map inputs i.e. topographic, land use and soil maps, are provided to this model in the form of well treated digital raster maps in addition to several model compatible databases prepared by using latest Remote Sensing and Geographical Information System techniques. Most of the equations are solved at HRU level in SWAT. Thus, this study is aimed at to test the applicability of SWAT model to simulate runoff response from sub-Himalayan Chaukhutia watershed.