The effect of the seawater intrusion on the Robinzon coastal spring

Abstract

The Robinzon Spring, located 70 m from the seacoast, is a freshwater, perennial spring with a yield ranging from the maximum 2 m3/s to the minimum 0.165 m3/s. The spring occurs at the contact between permeable carbonate rocks and impermeable flysch deposits. This contact is deeply weathered, eroded and submerged below sea level. Such conditions emphasize the delicate relationship between the fresh- and seawater. The objective of the study was to shed more light on the hydrogeological setting of the spring's underground recharge area by means of borehole measurements and preexisting knowledge about the dynamics of the fresh- and seawater acquired from similar cases. The spring's underground area is divided into three zones: (i) zone of good water circulation (rockfall material and fractured dolomite), (ii) zone of poor water circulation (massive dolomites), and (iii) zone of 'trapped' water (contact between the dolomite and flysch deposits).