engleski

Interdisciplinary investigations of managed aquifer recharge potential on the small island of Vis (Croatia)

Managed aquifer recharge (MAR) refers to a suite of methods by which excess surface water is diverted underground where it is stored for subsequent recovery. Although MAR has a long history of implementation in aquifers with intergranular porosity, its application in the karst environment presents major challenges due to the high heterogeneity of karst aquifers (Dillon et al., 2019). This research was focused on conducting a MAR feasibility study on the island of Vis, a small karstic island in the Croatian part of the Adriatic Sea, where favorable geological and hydrogeological conditions enabled the formation of high-quality karst aquifers, making the island autonomous in terms of water supply. The island’s main aquifer is protected from seawater intrusions by several hydrogeological barriers, however, climate change and high seasonal pressures related to tourism pose a threat to the future availability of freshwater. To investigate whether a MAR operation is feasible and suitable for the karst aquifer on Vis, detailed field and laboratory investigations were carried out. Field investigations included in-situ measurements of physicochemical parameters on water samples from springs and boreholes, groundwater monitoring (conductivity, temperature, and water levels), geophysical methods (ERT, magnetotellurics, and seismic refraction), and structural measurements. Laboratory analyses included measurements of stable water isotopes, principal cations and anions, tritium activity, and analyses of stable isotopes from dissolved sulphates. The results corroborated the available conceptual model of the water resources detailing the geometry of the carbonate aquifer and of the fracture systems driving the water circulation. A 3D numerical model (FEFLOW) of the island will be developed to simulate various scenarios of climate change, with and without MAR. The integration of the obtained results with historical data and previous research will be used for implementing efficient and sustainable management of the karst aquifer through MAR or alternative solutions on Vis island.

Vis island ; Groundwater ; Karst hydrogeology ; Climate change ; Managed aquifer recharge

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