Hydrogeological setting and groundwater safety in an overexploitation situation: the Valle Maggiore context (Piedmont, Italy)

The well field in the Valle Maggiore, at which about 14,000,000 m3/year are extracted by means of 37 water wells, play a fundamental role in supplying drinking water to a large territory of the Asti district (Central Piedmont, Italy). Since 1996 to present, a groundwater withdrawal of about 1,000,000 m3/year has been recorded at the well field, because of a continuous increase of water demand. This situation has caused an overexploitation of the deep aquifer, evidenced by the progressive lowering of the piezometric level (locally up to 0,8 m/year) and the consequent spatial reduction of the artesian zone. The study of the geologic setting and the hydrogeologic reconstruction of a wide area around the Valle Maggiore were the first step of this work. From these elaborations, three hydrogeologic complexes have been recognized. In order to decrease the overexploitation, four different scenarios for a better groundwater management at Valle Maggiore well field have been proposed.All the simulations provide an increase of the piezometric level, even up to 30 m. The fourth scenario seems to ensure the better performances: the piezometric level rises up to 27 m in the Valle Maggiore area and the current amount of drinking water would be preserved without having to build new wells.