Climate change and Mediterranean coastal karst aquifers: the case of Salento (southern Italy)

Abstract

Second half of the 20th century was characterized by an increase of groundwater discharge. Numerous aquifers are overexploited in the world and in particular in the Mediterranean area. Problems tie to overexploitation, as piezometric decline and increase of seawater intrusion, are amplified in karst coastal aquifers where the whole effect could be a groundwater quality and quantity degradation. Focusing on Mediterranean countries, most part of coastal aquifers of Spain, France, Portugal, Slovenia, Croatia, Greece, Albania, Turkey, and Italy are karstic and affected, to different degrees, by seawater intrusion due high pumping extraction rates and low recharge. (COST, 2005; Polemio et al., 2010). Climate change may particularly aggravate these requirements, especially in the Mediterranean areas, due to the combined effects of semiarid condition climate, or reduced recharge and consequent increase of discharge (Cotecchia et al., 2003; Polemio 2005; Polemio et al., 2009). The general purpose of this paper is to prove the capability of large-scale numerical models in management of groundwater, in particular for achieve forecast scenarios to evaluate the impacts of climate change on groundwater resources of karst coastal aquifer of Salento (Southern Italy). The computer codes selected for numerical groundwater modelling were MODFLOW and SEAWAT. Three forecast transient scenarios, referred to 2001-2020, 2021-2040 and 2041-2060, were implemented, on the basis of calibrated and validated model, with the aim to predicting the evolution of piezometric level and seawater intrusion. The scenarios were discussed considering the effects of climate change, sea level rise and change of sea salinity.