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Groundwater protection in fractured media: a vulnerability-based approach for delineating protection zones in Switzerland
Auteur(s)
Pochon, Alain
Tripet, Jean-Pierre
Kozel, Ronald
Meylan, Benjamin
Sinreich, Michael
Date de parution
2008
In
Hydrogeology Journal
Vol.
7
No
16
De la page
1267
A la page
1281
Résumé
A vulnerability-based approach for delineating groundwater protection zones around springs in fractured media has been developed to implement Swiss water-protection regulations. It takes into consideration the diversity of hydrogeological conditions observed in fractured aquifers and provides individual solutions for each type of setting. A decision process allows for selecting one of three methods, depending on the spring vulnerability and the heterogeneity of the aquifer. At the first stage, an evaluation of spring vulnerability is required, which is essentially based on spring hydrographs and groundwater quality monitoring. In case of a low vulnerability of the spring, a simplified method using a fixed radius approach ("distance method") is applied. For vulnerable springs, additional investigations must be completed during a second stage to better characterize the aquifer properties, especially in terms of heterogeneity. This second stage includes a detailed hydrogeological survey and tracer testing. If the aquifer is assessed as slightly heterogeneous, the delineation of protection zones is performed using a calculated radius approach based on tracer test results ("isochrone method"). If the heterogeneity is high, a groundwater vulnerability mapping method is applied ("DISCO method"), based on evaluating discontinuities, protective cover and runoff parameters. Each method is illustrated by a case study.
Type de publication
Resource Types::text::journal::journal article
