Use Of Soil And Water Assessment Tool For Sediment Modeling

The soil is the natural, dynamic, heterogeneous, non-renewable resource, which supports plant and animal life. It is the most precious primary resource for the very existence of humankind. Soil and water problems in Varanasi are stressed due to rising population and climate change. The studies showed that the changing climate and intense human activities would complicate the situation endangering the water and soil resources. To support sustainable uses of these resources, an appropriate model is required in this area and to develop such model runoff, evapotranspiration and soil erosion modeling is essential. In this paper, soil and water assessment tool (SWAT) is used to model sediment yield processes of Varanasi watershed in the Ganga basin. Ten years of daily meteorological data, soil data procured from the National Bureau of Soil Survey, digital elevation model of 90 m resolution and Landsat 8 satellite imagery are used as inputs. The watershed was divided into 39 sub-basin for analysis and modeling. The Sufi-2, Parasol and GLUE algorithms were used for validation and calibration. The data was divided into two halves of 5 years each. First half was used for calibration and the second half for validation of the model. The results revealed that more than half of the annual precipitation water is lost in evapotranspiration and runoff. Sediment yield of various soil erosion-prone areas was estimated. The results from modeling would be further used to propose and model multiple water conservation and sediment filtration basin structures in the flood and soil erosion impacted areas. This study also revealed that how the SWAT model is valid to be used in hydrological and soil erosion modeling. These results can be further implemented for improving water and soil quality of the watershed.