Water supply in the Alt Emporda area was obtained from ground water until 1987 when its high salinity contents forced managers to use surface water instead to satisfy the demand. In dry years, however, surface water may not suffice. In this paper, we study the hydrological behavior of this leaky aquifer system to finally estimate the feasibility of supplying low salinity ground water to complete local needs. We start on the hypothesis that aquitard salt leaching is the main factor of salinity. Hydrogeological parameters of this leaky aquifer system are estimated using standard pumping tests, and fitting simulated drawdown using monthly withdrawal rates with head levels recorded from 1984 to 1987 in selected piezometers. Based on a mass-balance approach, we conclude that the aquitard did not behave as the only cause 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 another source of salinity, as shown by simulated drawdowns.
|Journal||Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere|
|Publication status||Published - 1 Jan 1999|