Existing Risk and Future Susceptibility of Soil Erosion in the Silabati River Basin, Eastern India

The process by which water removes particles from the earth’s crust, either through the direct impact of raindrops or surface runoff, is known as water erosion. This phenomenon is a natural part of the landscape’s evolution, referred to as geologic erosion, and to some extent it is unavoidable. In the present study, the Revised Universal Soil Loss Equation (RUSLE) and the Frequency Ratio (FR) are utilized to estimate the current rate of soil erosion and to predict future areas susceptible to erosion, respectively. The average rate of soil erosion in the Silabati River Basin is estimated 4.35 t/ha/yr., well below the basin’s maximum permissible rate (the ’T’ value) of 12.5 t/ha/yr. However, 12.03% of the basin exceeds this threshold. Nineteen soil erosion conditioning factors, viz., Rainfall, Elevation, Slope of surface, Aspect of slope, Topographic curvature, Lithology, Geomorphology, Percent of Sand, Silt, Clay, and Organic carbon, Land Use/Land Cover (LULC), Vegetation Concentration, Drainage density (Dd), Topographic Wetness Index (TWI), Terrain Roughness Index (TRI), Stream Power Index (SPI), Distance from road and river were considered for soil erosion susceptibility assessment. Areas with high susceptibility to erosion are primarily located in the upper river basin, characterized by high elevation, steep slopes, high sand, silt content, and low clay and soil organic carbon (SOC). Moderately susceptible areas are found alongside the river and in lower basin regions, where steep slopes and agricultural activities dominate. The central areas have low susceptibility due to dense vegetation. Validation procedures have been carried out using the Receiver Operating Characteristic (ROC) curve to assess the reliability of the adopted model for soil erosion susceptibility. Assessing soil erosion susceptibility using a geo-statistical bi-variate approach can be highly effective for planning erosion control measures, a crucial step for integrated soil and water resources management in the River Basin.