Modelling the impact of climate change on river runoff and sediment yield in Mediterranean basins: the Carapelle case study (Apulia, Italy)

Ossama M M Abdelwahab ¹ Giovanni Francesco Ricci ^1* Francesco Gentile ¹ Anna Maria De Girolamo ²

• ¹ University of Bari Aldo Moro, Bari, Italy
• ² Water Research Institute IRSA, National Research Council of Italy CNR, Bari, Italy

This study aims at analyzing the climate change impact on streamflow and sediment yield in a Mediterranean basin (Carapelle, Apulia Region Italy). Three climate model projections (CMCC, MPI, EC-EARTH) were used after bias correction. Statistical measures indicated enhanced fit between observed and corrected data post-bias correction. The SWAT model was used to simulate hydrology and sediment yield. It was calibrated and validated using measured data (2004-2011), showing satisfactory performance for streamflow and sediment load simulations. Climate model projections predicted for future (2030-2050) an increase of temperature (up to 1.3 °C) and a decrease in average annual rainfall compared to the baseline (up to 38%). Consequently, reductions in water yield and sediment load were predicted. The CMCC model projected the highest reduction in mean annual flow (67%), while a smaller reduction was predicted by EC-EARTH (7%) and MPI (35%). Sediment load reductions was quantified in 52.8% by the CMCC, 41.7% by MPI and 18.1% by the EC-EARTH model. However, the spatial analysis revealed soil erosion remained critical under CC (sediment yield >10t ha-1). Steep slope areas with wheat cultivation were more susceptible to soil erosion. Based on the results of this study, the water resources management will assume an important role to balance the reduced water availability expected for future. In addition, conservative agricultural management practices should be implemented to reduce soil erosion.