Effectiveness of geophysical surveys for water wells relocation in overexploited aquifers (the example of Maggiore and Traversola Valleys, Northwestern Italy)

Abstract

Aquifer overexploitation is a common problem in drinking water management. This will become more and more important given the general reduction of water resources. To overcome overexploitation, one of the most adopted solution is the relocation of extraction wells. To establish the positions of new wells, a precise knowledge of the hydrogeological setting is required. Specific surveys are therefore necessary to obtain information over wide investigation zones. Geophysical methods, particularly electromagnetic and electrical, can be useful with this aim. In the present paper a case history on the combined use of ERT (electrical Resistivity Tomography) and TDEM (Time Domain Electromagnetic) soundings is reported.Surveys have been performed within the Maggiore and Traversola Valleys, to investigate the uppermost part of the Quaternary deposits, hosting the near surface aquifer. The electromagnetic data have been inverted with a Spatially Constrained approach by assuming a quasi 1D model of the sub-surface. Geophysical surveys allowed for depicting the depth and lateral continuity of the supposed aquifer level in the surveyed area up to a depth of about 200 m and proposing potential positions for well relocation.

Hydrogeology of the western Po plain (Piedmont, NW Italy)

“…The hydrogeological map was produced in English and Italian because this study is addressed not only to an international audience of researchers, but also to public administrations, stakeholders, and local professionals working on groundwater management. More specifically, this map represents a basic step for future investigations (aquifer vulnerability, recharge areas, wellhead protection areas …) or studies aimed at solving current problems of groundwater resources in Piedmont, such as groundwater contamination (Lasagna et al, 2013(Lasagna et al, , 2015(Lasagna et al, , 2016b(Lasagna et al, , 2018Lasagna & De Luca, 2016Martinelli et al, 2018), overexploitation (De Luca et al, 2018;Lasagna et al, 2014Lasagna et al, , 2019a, piezometric level variations as response to climate change (Lasagna et al, 2019b(Lasagna et al, , 2020.…”