Modelling and management of a Mediterranean karstic coastal aquifer under the effects of seawater intrusion and climate change

Abstract

The study and management of the groundwater resources of a large, deep, coastal, karstic aquifer represent a very complex hydrogeological problem. Here, this problem is successfully approached by using an equivalent porous continuous medium (EPCM) to represent a karstic Apulian aquifer (southern Italy). This aquifer, which is located on a peninsula and extends to hundreds of metres depth, is the sole local source of high-quality water resources. These resources are at risk due to overexploitation, climate change and seawater intrusion. The model was based on MODFLOW and SEAWAT codes. Piezometric and salinity variations from 1930 to 2060 were simulated under three past scenarios (up to 1999) and three future scenarios that consider climate change, different types of discharge, and changes in sea level and salinity. The model was validated using surveyed piezometric and salinity data. An evident piezometric drop was confirmed for the past period (until 1999); a similar dramatic drop appears to be likely in the future. The lateral intrusion and upconing effects of seawater intrusion were non-negligible in the past and will be considerable in the future. All phenomena considered here, including sea level and sea salinity, showed non-negligible effects on coastal groundwater.

Monitoring and Management of Karstic Coastal Groundwater in a Changing Environment (Southern Italy): A Review of a Regional Experience

“…These trends were also observed in Italy, where seawater intrusion is the main cause of groundwater quality degradation in coastal karst aquifers, the largest of which are located in the Apulian region [15] ( Figure 3). Climate change, particularly with regard to changes in temperature, precipitation, sea level, and sea water salinity, is a key factor for future decades, potentially worsening the risks of groundwater degradation, as in the case of coastal Mediterranean aquifers [16,17].…”

“…Water 2016, 8,148 3 of 16 In previous decades, climate variations and droughts in the Mediterranean contributed to the increasing overexploitation trend, with negative consequences in terms of seawater intrusion [6,7,[11][12][13][14]. These trends were also observed in Italy, where seawater intrusion is the main cause of groundwater quality degradation in coastal karst aquifers, the largest of which are located in the Apulian region [15] (Figure 3).…”

“…The implementation of new management strategies of groundwater resources has become extremely important [15,23,24]. These strategies have to be validated with the use of numerical models of key processes [2,16]. [18,19]).…”

The Compatibility of Geothermal Power Plants with Groundwater Dependent Ecosystems: The Case of the Cesine Wetland (Southern Italy)

“…It outcrops inland; this portion of the Salento Peninsula is recharged only by direct rainfall infiltration [29]. This aquifer is confined in the study area and show hydraulic conductivity from medium to high fracturing and karst.…”

“…The groundwater flow in the Salento peninsula can be schematized considering two different types of aquifers [29]. The former is represented by a unique aquifer, hundreds of meters thick, which correspond to the intensely fissured and karstic carbonate Mesozoic basement; it extends over the whole Salento Peninsula but does not outcrop in the study area; it is hereinafter called deep aquifer [30,31].…”