Highlights • The present study measured the C factor value using NDVI time series, extracted from Landsat 8 OLI imageries. • The forest areas of the basin are more prone to soil erosion, compared to any other LULC category. • Upraised slope significantly affects soil loss rate and sediment yield. • Around 174.31 Km² (9.16 %) land area contributed 57.54 % of gross soil loss. • The upstream parts of the river basin are highly susceptible to soil erosion.

Abstract As a major contributor of land degradation, water borne soil erosion poses a threat to environmental and socioeconomic sustainability worldwide. Recently, various anthropogenic factors have aggravated soil erosion related problems in most of the humid and semi arid parts of the developing countries like India. Therefore, accurate quantification of the spatially distributed soil erosion along with the identification of erosion hot spots is of paramount significance for designing extensive management strategies to combat erosion hazard. The present study aimed to estimate mean annual soil loss in a tropical river basin such as Kumari river basin (KRB, area: 195125 ha) in the Chotanagpur plateau region in India. In addition, the study also quantified mean sediment yield and identified the main sediment sources within the basin. For these purposes, the present study introduced a raster based spatially distributed approach that integrated RUSLE and sediment delivery ratio (SDR) models with remote sensing (RS) and GIS. The results depicted that annual soil loss within the basin varied from 0 to 208.34 t ha ^{– 1} yr ^{– 1} with an average of 1.92 t ha ^{– 1} yr ^{– 1}. The computed annual soil loss was about 364.05 × 10³ tonnes, of these, 209.46 × 10³ (∼58 %) were lost from only 8.93 % of the total basin area at intolerable rate. Similarly, the estimated sediment yield within the basin ranged from 0 to 64.53 t ha ^{– 1} yr ^{– 1} with a mean of 1.15 t ha ^{– 1} yr ^{– 1} and followed a similar distribution pattern of soil erosion. Being characterized by steep topography, the forest patches in the upstream part of the basin showed the most critical erosion risk. The methodology adopted in the current research displayed acceptable correctness and enabled spotting of most vulnerable areas of water erosion and critical sediment sources, initiating a comprehensive anticipating aid for the implementation of proper land management and soil conservation plans. This perspective is surmised to be helpful for extensive study of water erosion in other tropical river basins.