SWAT-Based Development of Soil and Water Conservation Best Management Practices

Streamflow and sediment yield are key components of river systems and are strongly influenced by anthropogenic land use changes. Soil erosion remains a critical environmental concern, degrading crop productivity, water quality, aquatic ecosystems, and river morphology. Sediment transported from croplands to rivers and reservoirs introduces contaminants and exacerbates water pollution. This study evaluates the effectiveness of Best Management Practices (BMPs) in the Nagavali and Vamsadhara watersheds using a calibrated and validated Soil and Water Assessment Tool (SWAT) model, targeting high sediment-yielding areas. BMP scenarios—including filter strips, sedimentation ponds, contour farming, and contour stone bunding—were assessed at watershed and sub-watershed scales. At the watershed scale, 10 m filter strips reduced sediment yield by 29% and 53% in the Nagavali and Vamsadhara watersheds, respectively. Combined BMP implementation further reduced sediment yield by 37% and 72%, and streamflow by 16.5% and 54%, respectively. These reductions persisted under future climate scenarios. The results highlight the potential of targeted BMP implementation to enhance watershed sustainability and support informed land and water management decisions.