The fragile and immature soils in the sloping terrain of the Himalayan landscape is susceptible to soil erosion. Besides this, climate change may significantly enhance the soil erosion. Policymaking needs reliable estimation of the soil erosion to suggest suitable conservation measures. Hence, keeping this in view, the study was carried out to simulate climate change impacts on soil erosion for a small watershed of Lesser Himalayan region employing calibrated SWAT model. The model was calibrated and validated using the observed surface runoff and sediment yield data obtained from the watershed gauging station. The SWAT model performed well in estimating surface runoff (r(2) =0.85) and sediment yield (r(2) =0.86) with high model Nash-Sutcliffe Efficiency (NSE) for surface runoff (NSE= 0.81) and sediment yield (NSE= 0.70). The highest average soil loss was estimated from the scrubland (42.8 tons ha(-1) year(-1)) and the least from the moderately dense forest (20.1 tons ha(-1) year(-1)) during the current period. Subsequently, the calibrated SWAT model simulated to predict soil erosion in future. MarkSim DSSAT weather generator is a web-based tool used to obtain future climate scenarios. The downscaled General Circulation Model (GCM) projections were obtained from the MarkSim DSSAT weather generator tool. These projections Representative Concentration Pathway (RCP) 4.5 and 8.5 indicated an increase in rainfall depth of 12.3-14.2%. The predicted soil erosion revealed an increase in annual soil erosion rate from 18.1 to 20.9% under various emission scenarios during the twenty-first century. The outcomes exposed that climate change may increase the variability and rates of soil erosion by increasing rainfall intensities and depths. The comprehensive information generated from the study will help the government and policymakers to suggest suitable conservation measures in preparing sustainable land use plan in the Himalayan region.
Sooryamol, KR; Kumar, S; Regina, M; Raj, AD
Modelling climate change impact on soil erosion in a watershed of north-western Lesser Himalayan region
Journal Of Sedimentary Environments