The Novljanska Žrnovnica pumping station is located in the Žrnovnca bay near the town of Novi Vinodolski, and it supplies water needs of the surrounding towns and villages. The catchment area is made of carbonate and clastic rocks and it has all the geological characteristics of of the Dinarides. During the summer months tourism booms and the need for drinking water is higher in comparison to the rest of the year. For this reason the system is connected to the water supply system of the town of Rijeka due to its stability and the possibility of water supply during this period. Excessive pumping of groundwater lowers the water level in relation to the natural state of an aquifer and thus changes the equilibrium conditions. Consequently, the salt water boundary shifts towards the upper parts of the aquifer where freshwater conditions previously prevailed. This problem was noticed back in the seventies and an attempt was made to solve it by installing an injection curtain that would prevent the contact between fresh and salt water. Later on, hydrogeological research was carried out with the aim of obtaining larger pumping quantities of water with fewertechnical interventions at the pumping station. Positive results were obtained in terms of directing the work towards the implementation of new catchment interventions in the vicinity of the existing ones and the idea of widening and deepening the injection curtain was abandoned.