SOIL LOSS ASSESSMENT IN KESINGA WATERSHED USING SWAT AND USLE

Abstract

Land system change i.e. degradation of land is one of the nine principles of earth system which is often used to check the amount of destruction that has caused to nature. The term sixth mass extinction heard nowadays is also related to these principles. In the recent UNCCD (United Nations Convention To Combat Desertification) summit the Indian government announced to restore 26 million hectares of degraded land. The major factor that contributes to land degradation is soil erosion. In this work, the Tel river sub-basin’s southern part was taken for analysing the amount of soil getting eroded. The area of the catchment was 11400 sq.km. Soil loss assessment was performed using two models. First using Universal Soil Loss Equation (USLE) which is an empirical equation wherein various maps of factors were prepared and overlay operation was performed using Geographic Information System (GIS). Another model used was SWAT ( Soil and Water Assessment Transport) in which HRUs (Hydrologic Response Units ) are created and analysis was done. The result obtained from SWAT is then calibrated and validated using SWAT- CUP (Calibration and Uncertainty Procedure). The comparison was done between the output and actual sediment yield from the Annual Sediment Report of CWC (Central Water Commission). The soil loss estimated using USLE was 0.801 MT whereas from SWAT it is 1.092 MT. The observed data is 0.961 MT (million tonnes). Soil loss was overestimated when SWAT was used and underestimated when performed using USLE.