Climatic Characterization and Response of Water Resources to Climate Change in Limestone Areas: Considerations on the Importance of Geological Setting

Abstract

This work analyzes the response of springs fed by karst/fractured limestone aquifers, which extensively outcrop in central Italy, to climatic variations. In the central Italy area, climatic variations are represented by a general decrease in annual and winter precipitation. It is shown how groundwater regime, the discharge of springs, and their response to climate change depend to a great extent on the geologic and structural setting of the system. Some mountain springs of central Italy are local systems representing the overflow of a deeper regional flow feeding larger base springs, often of poor quality. A dynamic groundwater divide separates the recharge areas of base springs from those of local springs: if, due to low recharge, the piezometric surface lowers, the watershed moves toward systems located at higher altitudes, reducing their recharge areas. Therefore, local springs connected to a base flow are more vulnerable to climate change than those which are not. The Bagnara and Lupa springs, taken as examples, have similar mean discharges (approximately