Assessment of soil erosion in upper tungabhadra sub basin by using universal soil loss equation and geospatial techniques

Abstract

Soil erosion is an acute problem in India. Soil erosion not only affects the agriculture sector by directly decreasing the crop productivity but also indirectly exacerbates water scarcity by reducing the storage capacity of reservoirs. It is important but very difficult to estimate the precise extent of soil lost in a particular hydrological event of a watershed. Many experimental and theoretical methods were proposed to get the volume of soil lost. Graphical models were also developed for finding the computational and graphical results for soil erosion using different software programmes. Remote Sensing and Geographical Information System Software are emerging as important tools for estimating soil erosion. The main objective of the present study is to find out the quantity of soil lost from Upper Tungabhadra Sub basin by using Universal Soil Loss Equation (USLE), Remote Sensing (RS) and Geographical Information System (GIS). This is accomplished by determining the Soil erodibility (K), Rainfall erosivity (R), Topographic factor (LS), cropping factor (C) and conservation factor (P). The Tungabhadra Upper sub basin constitutes 45 watersheds having different geographical patterns with an average annual rainfall varying from 200 to 2500 mm. The factors affecting the erosion have been obtained by developing Rainfall erosivity, soil erodibility, Digital Elevation Model, Land use Land cover, and Annual rainfall maps.