Abstract
There is an increasing demand for groundwater vulnerability maps which illustrate the exposure of aquifers against pollution. These maps show areas of greatest potential for groundwater contamination on the basis of local subsurface conditions. Parameters affecting vulnerability are mainly permeability and thickness of each protective layer. For unconsolidated sediments, the permeability is strongly related to the clay content, which can be deduced from indirect resistivity methods, like electrical-imaging. Such geophysical methods can be of great help in groundwater vulnerability studies because they disturb neither the structure nor the dynamics of the soil. Sensibility analysis was performed of the electrical resistivity tomography method for accurately mapping soil media. Managers and public administrators may effectively use this method for assessing the potential risk of groundwater contamination. In the studied zone, electrical resistivity exhibits a wide range of variability that can be easily correlated to soil parameters, such as clay content and hydraulic conductivity. A numerical index of protection has been assessed from the geophysical information derived from 2D electrical resistivity tomography. This work represents a preliminary approach on the natural vulnerability evaluation of shallow aquifers at the Empordà basin (NE Spain) that is highly affected by diffuse pollution by nitrates.
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Casas, A., Himi, M., Diaz, Y. et al. Assessing aquifer vulnerability to pollutants by electrical resistivity tomography (ERT) at a nitrate vulnerable zone in NE Spain. Environ Geol 54, 515–520 (2008). https://doi.org/10.1007/s00254-007-0844-1
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DOI: https://doi.org/10.1007/s00254-007-0844-1