Estimation of Soil loss Using USLE Model for Kulhan Watershed, Chattisgarh- A Case Study

Abstract

Soil erosion is the common land degradation problem in the worldwide because of its economic use and environmental impacts. To estimate soil erosion and to establish soil erosion management plans, many computer models have been developed and used. Remote Sensing (RS) and Geographic Information System (GIS) being a well-known tool available for dealing with the major water resources problems, it is used in the present study. The objective of the present study is to estimate the annual soil loss using USLE model for Kulhan watershed of Shivnath basin, sub-basin of Mahanadi basin, Chhattisgarh using RS and GIS techniques. Land useland cover and topographical data for the study area was derived using GIS and carried out geographical data analysis. Data collection includes for the study were annual rainfall data, digital elevation model (DEM) from shuttle radar topographic mission (SRTM), land-use classification map and soil series maps were obtained from Chhattisgarh Council of Science and Technology (CCOST), Raipur, Chhattisgarh.The five major input parameters used in the study are rainfall erosivity factor (R), Length slope factor (LS), soil erodability factor (K), vegetation cover factor (C) and erosion control factor (P). The rainfall erosivity factor had been determined from annual rainfall data of study area. The soil survey data was used to develop the soil erodability factor and DEM of study area was used to generate topographic factor (LS). The value of cover management factor and support practice factor were obtained from land use land cover map. After generation of input parameters, analysis was performed for estimation of soil erosion using USLE model by spatial information analysis approach. The quantitative soil loss (t/ha/year) ranges were estimated and classified the watershed into different levels of soil erosion severity and also soil erosion index map was developed. The watershed is classified according to Indian condition as suggested by Singh et, al.(2002) into different erosion classes such as (>5) slight, (5-10) moderate, (10-20) high, (20-40) very high, (40-80) sever, (>80) very severe. It was found that average annual soil erosion for study area is 0.1783t/ha/yr and 83.97% of total area is under slight erosion risk class and only 0.45% of total area is under very severe class which is near the bank of main stream line.