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This project analyzes past groundwater trends and forecasts future scenarios in karst regions of the Mediterranean impacted by climate change. The study includes data collection, statistical analysis, and mathematical modeling to assess the effects on groundwater availability and seawater intrusion.
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The following activities will be developed at selected case studies in the Mediterranean region: The impact of climate change on ground water recharge in karst and carbonate rocks: Task 5.3.4 a) Identification and analysis of ground water trends in the past decades b) Application of selected climate scenario and forecast for the future decades
Groundwater trends in the past decades The identification of case study will be performed on the basis of • i) available data; • ii) significantly, as for hydrogeological features and quantitative pressures. Part of the effort will be devoted to the data collection (meteorological, hydrological, piezometric levels, etc). Data analysis will be supported by statistical methods
What is the response of groundwater to such a meteorological cycle? What is the quantitative interplay between drought, recharge decrease and increased groundwater overexploitations? Aquifer levels seem to have no particular recovery after the observed wet set.
Model forecast Mathematical models will be run under different climate scenarios in order to forecast the future decades evolution of groundwater availability (discharge and storage) in relation to the selected case study. The model will be able to define the reduction of coastal aquifer volumes due to the increase of seawater intrusion as a consequence of groundwater overexploitation.
Variation on groundwater storage during years Microsoft Excel Worksheet showing the computation of the intrusion extent Li
Xcoast x y Distance parallel y (m) Distance from coastline (m) Plot of 50% saltwater/freshwater interface with respect to the coastline by using the model equations and its transformation to the position Xi by mean of the coordinates of the coastline (Xcoast).
Model development Idealization of the parallel set of fractures and Ghyben-Herzberg sharp stationary interface under Dupuit assumption (horizontal motion).
Seawater extent, L: • Hs (m) is the depth (below the sea surface) at the outflow section of the 50% sharp interface saltwater/freshwater. Obviously, Hs=0 can also be set for zero discharge; • B(m) is the saturated aquifer thickness where =0 ; • bi (m) is the sum of the all horizontal apertures in the vertical aquifer column, while Nf is the total number of the horizontal fractures in the saturated thickness B.
Evaluation of seawater intrusion extent into freshwater, in vertical plans ZX at distance y between them, in order to locate the three-dimensional development of the intrusion.
Comparison of the freshwater outflow zones at Torre S. Isidoro: (a) springs monitored by Cotecchia (1977: 145-158); (b) springs visualized by Landsat Thematic Mapper photo (1997); (c) springs zones defined by computational procedures (1980 and 1999).
