HYDROGEOLOGICAL SURVEYS AND CONSIDERATION OF THE ENVIROMENTAL IMPACT OF INTENSIVE AGRICULTURE IN THE "CAMPO DE DALIAS" (ALMERIA, SPAIN).
The Instituto Tecnológico Geominero de España (I.T.G.E) has been performing hydrological surveys in the area since 25 years ago with the aim of understanding the behaviour and potenciality of these aquifers, misuse risks of them and to facilitate their rational management. The sea water intrusion is the main impact in the intensive agriculture at the present time. The importance of its socioeconomic impact is great as it will limit the use of this groundwater resources by spoiling the quality of the water demanded. The salinity is now affecting to some sectors of the aquifers.
The main findings of these hydrogeological investigations can be summarized in these points: 1. Existence of a very complex hydrogeological estructure (with two or more overlapped aquifers). 2. Difficulty to reach the adecuate knowledge of the dynamics of these aquifers because of the lacking of enough specific boreholes for the studies, having to use the irrigation infrastructure of private exploitation wells. 3. Existence of sea water intrusion in the main aquifers of the "Campo". 4. The technical problems in the construction of the needed deep boreholes, with the adecuate completion that is necessary for a trusty experimentation.
In this context, the study of the contamination of the aquifers by saline intrusion is very complicated: into the wells exist vertical currents between the aquifers drilled that mistake the control of the salinity evolution. The developping of the process in inland and deep zones of the main aquifers can't be known, nor the connections between these and the zones already affected. Also, the high cost of the measures control with the adequated register tools and the lacking of manual probes with adequate lenght and accuracy, are other important limitations for the study.