On the Variables to be Considered in Assessing the Impact of Climate Change to Alluvial Aquifers: A Case Study in Central Italy

AbstractMost of the scientific community agrees that global climate change is occurring with a general increase in mean overall temperature (+0.74±0.18°C from 1906-2005) and that the precipitation pattern in Europe is trending toward wetter conditions in the northern region and drier conditions in the southern and central-eastern regions. A much larger uncertainty concerns how the changes in precipitations will impact on the water resources, particularly on the groundwater. The goal of this paper is to investigate the variables to be considered in order to estimate the Sustainable Pumping Rate of an aquifer (SPR) in a context of climate change. For this goal the case study of the Petrignano d’Assisi porous aquifer has been considered, mainly fed by the inflow from the carbonatic ridges and by the effective infiltration; it is exploited since the 1970s through a well field (about 350 l/s). Changes in the precipitation regime could significantly affect the recharge to the aquifer and the related SPR. This study shows the key role played by the interactions of the aquifer with the surface bodies (rivers): in case of a significant decreasing in the effective infiltration, the aquifer system decreases the outflow to the rivers (base flow) leaving almost constant the sustainable pumping rate