Modeling the Effect of Different Management Practices for Soil Erosion Control in a Mediterranean Watershed

To counteract the threat of soil erosion, European countries are called to identify the high-risk erosion areas and to adopt Best Management Practices (BMPs). The Soil and Water Assessment Tool (SWAT) was used to identify the critical source areas, for the current management, in the Carapelle watershed, an agricultural watershed located in the Puglia region (Southern Italy). SWAT was calibrated and validated both manually and automatically, using SWAT-CUP, for runoff and sediment load at daily time scale for a 5-years period. Results show that in the Carapelle the average annual sediment load is 5.95 t ha-1 y-1. A threshold of sediment yield 10 t ha-1 y-1 was selected to discretize the high erosion-risk areas, resulting in 59 HRUs characterized by agricultural land use. Three BMPs scenarios, based on the regional policies, were modeled: contour farming, no-tillage and reforestation. No-tillage is the most effective scenario, reducing soil erosion to 4.20 t ha-1. The study offers to watershed managers a methodology to discretize the high erosion-risk areas, test and choose the most effective BMPs for sediment load reduction.