Climate change influence on runoff and soil losses in a rainfed basin with Mediterranean climate

The present research shows the results of possible effects of climate change on runoff and soil loss in a rainfed basin located in the Alt PenedSs and Anoia region (NE Spain). Viticulture is an important economic activity in this region, and vines for the production of high-quality wines and "cavas" are the main land use. Climate data for the period 2000-2012 and detailed soil and land use maps were used as input data for soil and water assessment tool to model the effects of climate change. The analysis compared simulated results for years with different climatic conditions during that period with predicted temperature and precipitation data for 2020, 2050 and 2080 based on data obtained from the Hadley Centre Coupled Model, version 3, A2 scenario and the trends observed in the area. The research confirmed the difficulty of predicting future soil loss in this region, which has very high inter-annual climate variability. Despite only small changes in precipitation, the model simulated a decrease in soil loss associated with a decrease in runoff, mainly driven by an increase in evapotranspiration. However, the trend in soil losses may vary when changes in precipitation balance the increase in evapotranspiration and when rainfall intensity increases. An increase in maximum rainfall intensity in spring and autumn (main rainy seasons) produced significant increases in soil loss: as high as 12 % for the 2020 scenario and 57 % for the 2050 scenario.