Identification of priority management practices for soil erosion control through estimation of runoff and sediment yield using soil and water assessment tool on Salma watershed in Afghanistan

Abstract

AbstractTo reduce reservoir sedimentation, sustainable water resource management necessitates the identification and control of significant erosion zones. The SWAT (soil and water assessment tool) distributed model was used to analyse runoff and sediment output, identify major erosion basins in the Salma dam, and assess best management practices for reducing sediment transport to reservoirs in order to extend their usable life. The groundwater delay and groundwater discharge regression for water discharge and soil depth, and Manning's coefficient of channel roughness for sediment yield, were the most sensitive factors. In the temporal assessment for the calibration and validation periods, SWAT reproduced the simulated daily flows and sediment loads. According to the water balance, actual evapotranspiration predominated, accounting for around 42% of the basin's average annual precipitation. The model revealed that the majority of the catchments were in the very severe erosion class, with extremely high‐prone catchments in the minority, demonstrating the model's potential for implementing and evaluating the effects of management options. According to the simulation exclusion fence, streambank stabilization, conservation crop rotation, check dams, brush layering, brush mattress and terracing can all be utilized to minimize soil erosion in the research areas. This research can be used to formulate a strategy for reducing sediment loads in the Salma as well as similar watersheds in Afghanistan.