Simulating the Impact of Conservation Interventions on Runoff and Sediment Yield in a Degraded Watershed Using the WEPP Model

Aim The present study aimed to use the WEPP model to simulate the impact of various conservation interventions on runoff and sediment yield and determine the optimum areal extent of a watershed to be treated economically. Materials Methods The study watershed (located in the Shivalik region of North-West India) was divided into various hillslopes and channels. The input files required to run the WEPP model were prepared for each hillslope and channel. The WEPP model was calibrated and validated by using monitored hydrological data (2015-2019). The impact of check dams and sedimentation basins, individually and in combination, on runoff, sediment yield, and sediment delivery ratio was simulated. Findings The simulation results indicated that channel erosion is predominant in the watershed, and check dams are more efficient in controlling runoff and sediment yield than sedimentation basins. However, the coupled implementation of both interventions was much more effective than the individual implementation of each intervention. The simulated runoff and sediment yield decreased by 72% and 90%, respectively, with a significant reduction of about 95% in sediment delivery ratio (SDR) compared to the untreated watershed. The results further revealed that treating 66% of the watershed area with both the interventions can be considered as an optimum area that should be treated. Conclusion In the absence of any recommendations for implementing management interventions in the Shivalik region of India, the results of the present study would serve as guidelines for treating degraded watersheds for their rehabilitation under limited financial resources.