Isotopic and hydrogeological characterisation of the Narces de la Sauvetat (Haute-Loire) site: research report before site planning - Final report

This study addressed the application of isotopic tools to characterise and quantify, if possible, the circulation of underground waters in the peat-land of Narces de la Sauvetat. It is based on the combined analysis of geochemical and hydrogeological approaches. The study of field data (conductivity, temperature, flow rate, piezometric measurements) and the hydrogeological approach demonstrate that several aquifers contribute to the supply of the peat-land. The interpretation of water geochemical analyses and of isotopic analyses of usual or innovating isotopes (water molecule, strontium, lithium) allows water exchange directions and rates within the peat-land to be characterised and assessed. These elements can be used to propose adequate conditions for a refilling of the peat-land.