Influence of climatic changes on groundwater resources: the case of Monte Cucco (Central Italy)

In Central Italy, temperature increased and rainfall decreased during the 20th century; according to the “analogous approach” and to the latest IPCC report, a groundwater recharge decrease of about 20% is likely to occur in the next decades. This will cause a decrease in groundwater resources. The impact of climatic variations on groundwater should be evaluated by means of site specific studies, as the geological framework is almost as important as the recharge variations. Presented here is the case of Monte Cucco (Central Apennines, Italy), which is an east-vergent asymmetric anticline, delimited by a thrust fault on the east side. The anticline core is made of limestones, bounded by marly formations. Many springs, which supply high quality drinkable water, emerge at the contact between limestones and marls and/or between limestones and the thrust line. The west springs have a higher discharge than the east springs, which are located at higher elevation. The structure’s hydrogeological budget indicates that roughly 30% of the recharge feeds not the springs, but a deeper regional flow, probably directed southwest. The recharge areas of springs and of the regional flow are delimited by dynamic piezometric divides, which, as the water table lowers, move towards the higher springs, whose recharge area shrinks. Since the deep regional flow in Monte Cucco is at a lower elevation than the local springs, the local springs’ discharge will be more influenced by a decrease in the recharge than the regional flow, with the greater impact on the east springs.