Water exploration on the Lastove Island (Croatia) by electrical tomography and seismic methods

Water exploration was carried out at the island of Lastovo, situated farthest from the Croatian Adriatic coast. The investigated area is situated in a tipical karst field, close to the Lastovo town, with the name Prgovo Polje (Prgovo Field). There are several exploited water wells in this area, which produce 2-3 l/s of water, but this is not sufficient because of the growing demands for water. The main goal of this water exploration was to capture more water, minimum of 5-6 l/s. Previous explorations and wells made in the sixtees were aimed at very shallow aquifers, mainly fine-grained sands, but because of the strong pumping, water has become brackish and has to be desalted by adequate technology. With respect to the fact that more water can only be captured from deeper aquifers, target rocks were fractured carbonate rocks in the bedrock of clastics. Since the infrastructure in the area of Prgovo Polje is mainly completed, the first goal was to discover new resources in this area. The secondary goal was to get the water of as low a salinity as possible, since the price of desalinization technology depends on the water salinity.