Affiliation: | a Jeune Équipe “Contraintes, Déformations, Écoulements”, Faculté des Sciences, place Leclerc, 25030 Besançon Cedex, France b Laboratoire d'hydrogéologie, Faculté des Sciences, 33 rue Louis Pasteur, 84000 Avignon, France |
Abstract: | The much contrasted orographic and climatic characters of southeastern France serve to establish a hydrological balance of the porous aquifers in the region. Comparing a regional average gradient of 18O content versus elevation, which was calculated on low-water period karst waters content, with a −10.5‰ average δ of Alpine rivers, an estimate of the percentages brought to these aquifers is proposed under the form of an abacus. It appears that the main groundwaters of the Var, the Durance and the Rhône are fed by an average of 20–30% of Provençal underground contribution, and 70–80% shallow contribution from the Alpine rivers. These figures reveal that local supplies range between 25 and 10% of the average yearly discharge flowing in the porous and shallow aquifers. |