Effects of Climatic Changes on Groundwater Availability in a Semi-arid Mediterranean Region

The effects of climatic changes on rain amount and distribution during the year to-gether with the consequences on availability of water resources are ongoing challeng-es. These problems are particularly striking on semi-arid regions, which are traditional-ly affected by water scarcity. The Mediterranean basin is characterized by semi-arid climate, moreover, some Mediterranean regions have high-permeability karst areas, with poor availability of shallow water. Therefore, in these regions groundwater con-stitutes the main autochthonous water resource. Aquifers are mostly fed by direct rainfalls, whereas these produce an effective infiltration. However one effect of climat-ic changes is the decreasing of precipitations and the change of their distribution dur-ing the year, conditioning the amount of infiltrating water. This is due to the increas-ing number of high intensity rainfall events as well as to the increasing of summer precipitations. These events notoriously produce high runoff, while infiltration is quite limited. Here this issue is investigated looking at long timeseries of precipitations and piezometric data for two aquifers in south Apulia, southeast Italy.