According to María Luisa Calvache Quesada, researcher in charge of project and professor of the Department of Geodynamics of the UGR, the dam, approximately located 14 kilometres upstream of the aquifer, will produce an alteration in river Guadalfeo´s volume of water and in the alluvial flow. To determine such effects in a quantitative way, the researchers have prepared a mathematic model that reproduces the hydrodynamic operation and the aquifer’s hydrochemistry, according to specific parameters. They have considered four scenes in which they have modified the values that contribute to refill the aquifer, such as the volume of river Guadalfeo, the volume that flows under the stream through the alluvial and, indirectly, the return by irrigation and, on the other hand, water extractions.
As a result, the scientists have obtained an aquifer’s vulnerability map to discern the most vulnerable areas according to three factors: variations in the subterranean water level, the pumped volume and the advance of the saline wedge.
Of the four areas, the one located at the east of the watercourse of the Brujas shows the lower vulnerability degree, against the area located at the northwest of river Guadalfeo, very vulnerable due to the larger extractions and piezometric level variations than in the rest of the aquifer, although the sea intrusion is not be important in this area as it has no direct contact with sea water.
Salobreña, a very vulnerable area
The area of Salobreña shows a high vulnerability level, although the advance of the saline wedge is lower. Finally, the area of the old mouth of the river shows a medium vulnerability level, although sea intrusion is very important here as there are numerous permeable materials and sea water could advance inland very easily.
According to the analysis, variables and models used in the study, the researchers conclude that the incidence of the hydraulic work will depend on the management of the resource to maintain the current conditions of the subterranean dams. The researchers have suggested the distribution of control points to alert to possible extreme conditions to be lightened with an ‘emergence supply’ from the river or the alluvial.
The researchers have been collecting data for four years and have established the initial conditions of the subterranean dam. According to the scientists, this is the most important aquifer of the coast of Granada due to the quantity and quality of this water resource.
Reference
Professor María Luisa Calvache Quesada. Department of Geodynamics
Phone number. 958 244 031 / 958 243 352.
E-mail. calvache@ugr.es
