Simulación de diferentes alternativas de gestión de los recursos hídricos del acuífero costero del río Verde (Almuñécar, España)

Abstract

The effects of various alternatives in managing the water from a coastal aquifer with sea-water intrusion problems (the river Verde alluvial aquifer, Almuñecar, Granada, Spain) have been analyzed by means of a finite element approximation. The differential equation which describes the horizontal flow of groundwater and the movement of a sharp interface between the fresh and salt water is solved in a steady state regimen for boundaries with flow and open boundary conditions. This stationary solution has shown very accurate results in calculating freshwater potentials, thicknesses of fresh and salt water, discharges of fresh water and the intrusion of salt water along the coast. Various alternatives were simulated in the aquifer which included: the operation of the planned Otivar reservoir at the head of the catchment basin, changes in the location of extractions from the aquifer, and artificial recharge by urban waste water in the proximity of the coast. These simulations revealed that a considerable advance in the interface is to be expected if the current pumping exploitation continues and a significant part of the surface flow of the river Verde is channeled from the planned Otivar reservoir to irrigate the Almuñécar plain. On the other hand, the injection of urban waste water in the proximity of the coast would contribute to limiting the advance of the interface in the aquifer. However, the replacement of exploitation by pumping wells, currently spread aH over the aquifer's surface area, by a comparatively shallower extraction close to the coast, would seem to constitute the most effective way of containing the advance of the interface. e, even for small flows discharging into the sea as a consequence of intensive exploitation.