Electrical imaging as a non-destructive technique to estimate the vulnerability of shallow aquifers to point-source and diffuse pollution
by
Albert Casas
University of Barcelona (Spain)
Coauthors: Josefina C. Tapias, Mahjoub Himi, Albert Casas

The impact of industrial wastes and agricultural practices on groundwater quality is of particular concern by the fact that a great mass of the population receives their drinking water supply from shallow wells that may become irreversibly polluted. In order to protect groundwater there is an increasing demand for vulnerability maps which illustrate the exposure of aquifers against pollution. These maps are designed to show areas of greatest potential for groundwater contamination on the basis of local subsurface conditions. Parameters affecting groundwater vulnerability are, besides the depth to water table, the thickness and hydraulic properties of each protective layer. Groundwater protective layers covering groundwater table plays a crucial role in protecting groundwater from infiltrating contaminants. The protection depends heavily on the structure and texture of the groundwater covering layers. Sandy layers with low thickness will lead to a fast infiltration of contaminants whereas silty and clayed layers – because of their low hydraulic conductivity – have a higher protective potential. For soils and unconsolidated sediments, the permeability is strongly related to the clay content, which can be deduced indirectly by resistivity methods, like electrical-imaging. This paper shows the effectiveness of the proposed methodology.

Date received: September 4, 2004

Copyright © 2004 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caon-29.