The protection of karst water resources: the example of the Larzac karst plateau (south of France)

Wide karst plateaus extend in the carbonate rocks of the Grands Causses are a, north of Montpellier (south of France). They are surrounded hard rock ba se that feeds important rivers, as the Tarn River and tributaries, and cros ses plateaus creating deep gorges. The Larzac plateau, the most southern, m akes a link with the Meditterranean region. It is traversed by one of the n ational roads and another main road under construction from Clermont-Ferran d to Montpellier;pain. The karst water resource of the plateau, springs, is used as a water supply for the Millau area (30,000 inhabitants); but it al so recharges ce rivers, mainly during the summer and fall the water level i s low, in a region that is well known for water recreation activities, for fish farming and,, above all, for sheep farming and Roquefort cheese produc tion. The fundamental question was should the karst and its water resource be fully protected by strict regulations (for example as a nature reservati on) in land-use management of the plateau based upon the knowledge of its h ydrogeological functioning and its karst structure? Decisions, concerning t he similar to 500-km(2) area were elaborated from detailed hydrogeological studies, which included natural and artificial tracing, analysis of aquifer functioning, landscape analysis, and assessment and mapping. Recommendatio ns proposed to local and regional decision makers to define what were the p references in terms of water resource protection and water quality restorat ion. Following such an approach in a karst area is not easy for hydrogeolog ists or for decision makers. In non-karstic regions, protection zones curre ntly extend over small areas of a few square kilometers, which control of a small municipality. In the present example, the main watt recharge areas t hat extend respectively over 100 and 110 km(2). Included some of which use them for their water supply, whereas others an and land management project. The recent French Water Act, which heritage, allows for general management by all the users, and it deals which it flows. The regulation tools seem v ery well suited to karst region is needed to educate users and decision mak ers, and with the help together in a frame work that is larger than the usu al municipal limits.