Insight from Surface Water-groundwater Interactions in an Alluvial Aquifer: Contributions of δ2H and δ18O of Water, δ34SSO4 and δ18OSO4 of Sulfates, 87Sr/86Sr Ratio

Abstract : Understanding water exchange between streams and groundwater, or surface water-groundwater interactions, is of primary importance for solving conflicts related to water use and for restoring water ecosystems. The main goal of this study was to demonstrate that combination of classic geochemical tools and isotopic tools (δ 2 H and δ 18 O of water, δ 34 S SO4 and δ 18 O SO4 of sulfates, 87 Sr/ 86 Sr) can lead to a better understanding of surface water-groundwater interactions for a main alluvial aquifer in the Alpes mountains (Isère River alluvial aquifer) used for drinking water supply. We report here the results that identified 3 aquifer units based on groundwater recharge.