GROUNDWATER RESOURCES FROM CARBONATEROCKS IN MOUNTAINOUS REGIONS:HYDROCHEMICAL AND ISOTOPIC SURVEY OFGROUNDWATERS IN THE WESTERN PYRENEES(FRANCE)

摘要

Carbonate rock aquifers are one of the main water supply sources for the FrenchWestern Pyrenees. The discontinuous structure of these reservoirs is a main obstacle tothe development of such resources. By the way, since no other aquifer can be tapped,many communities have decided to improve their knowledge of the main springs overthe whole region. Four sites have been considered from 2003 to 2006 and have beenthe object of multidisciplinary investigations including: geological mapping, geophysicalinvestigations, dye tracing experiments and in situ hydrochemical survey. Stable isotopeshave been analysed on both rainfall ( 18O, 2H) and spring waters ( 18O, 2H, 13C, 34S) inorder to evaluate the origin of groundwaters, their residence time within the systemsand to appreciate the occurrence of exchanges with other aquifers. Finally, this studyprovides a good example of how to include hydrogeochemistry and isotopic tools in awater supply management policy.