Salinization processes in a coastal leaky aquifer system (Alt Emporda, NE Spain)

Water supply in the Alt Emporda area was obtained from ground water until 1 987 when its high salinity contents forced managers to use surface water in stead to satisfy the demand. In dry years, however, surface water may not s uffice. In this paper, we study the hydrological behavior of this leaky aqu ifer system to finally estimate the feasibility of supplying low salinity g round water to complete local needs. We start on the hypothesis that aquita rd salt leaching is the main factor of salinity. Hydrogeological parameters of this leaky aquifer system are estimated using standard pumping tests, a nd fitting simulated drawdown using monthly withdrawal rates with head leve ls recorded from 1984 to 1987 in selected piezometers. Based on a mass-bala nce approach, we conclude that the aquitard did not behave as the only caus e of salinity. Sea water intruded in the upper unconfined source bed leaked to the aquifer through the aquitard, and it represented the main origin of chloride. Moreover, sea water intrusion in the main aquifer was likely ano ther source of salinity, as shown by simulated drawdowns. (C) 1999 Elsevier Science Ltd. All rights reserved.