Morphometric analysis to characterize the soil erosion susceptibility in the western part of lower Gangetic River basin, India

The present study is an attempt to identify the morphometric parameters for determining the soil erosion susceptibility (SES) in upper plateau fringe catchment and lower undulating plain catchment of Kangsabati basin using of multi-criteria decision model as compound factor (CF) and hydrological model as revised universal soil loss equation (RUSLE) under GIS platform. In this research, twenty morphometric parameters of three aspects, namely, linear, areal, and relief were taken from twenty-seven sub-basins to compute the morphometric priority rank using CF model. In contrary, soil erosion factors like rainfall, soil character, slope, and land cover management were taken to measure the potential annual soil erosion using RUSLE. The result showed that fourteen sub-basins in upper catchment (UC) with low compound value represent high morphometric priority rank whereas thirteen sub-basins in lower catchment (LC) with high compound value indicate lower morphometric priority rank. RUSLE estimated that higher rate of mean soil erosion (225 t ha−1 year−1) occurred in UC, whereas low rate of mean soil erosion (74 t ha−1 year−1) occurred in LC. Stepwise least regression of Akaike information criteria (AIC) showed that mean bifurcation ratio (p > 0.013), ruggedness index (p < 0.0001), and form factor (p > 0.034) are the best positive coefficient of erosion susceptibility (ES), but gradient ratio (p > 0.003) and elongation ratio (p > 0.024) have perfect inverse coefficient of high ES in LC. Gradient ratio (p > 0.044) is the only best inverse coefficient parameter of ES in LC due to presence of several conservative practices. Moreover, proper management strategy, effective morphometric, and erosion factors play vital role to determine the ES. © 2021, Saudi Society for Geosciences.