Assessing the Effects of Climate Change on streamflow and soil erosion in a Mediterranean Basin

This research investigates the impact of climate change on streamflow and sediment yield within the Carapelle basin, located in the Apulia Region of Italy, a Mediterranean environment. The study utilized three climate model projections, which were adjusted for bias to enhance accuracy. Statistical evaluations demonstrated an improved agreement between observed data and the corrected projections. The Soil and Water Assessment Tool (SWAT) was employed to model hydrological processes and sediment transport, with calibration and validation conducted using data from 2004 to 2011. The model exhibited satisfactory performance in simulating both streamflow and sediment load. Future projections for 2030-2050 indicate a potential temperature rise of up to 1.3°C and a reduction in average annual rainfall by as much as 38% relative to the baseline. These changes are expected to result in decreased water yield and sediment load. Among the climate models, the CMCC projection suggested the most significant decline in mean annual flow (67%), followed by reductions of 35% and 7% predicted by the MPI and EC-EARTH models, respectively. Sediment load reductions were estimated at 52.8% for CMCC, 41.7% for MPI, and 18.1% for EC-EARTH. Spatial analysis indicated that soil erosion remains a critical issue under future climate scenarios, particularly in areas with steep slopes and wheat cultivation, where sediment yield exceeds 10 t ha⁻¹. These findings underscore the necessity for proactive water resource management to address the anticipated decrease in water availability and highlight the importance of adopting sustainable agricultural practices to mitigate soil erosion.