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Defining protection for groundwater catchments used for human drinking water in karst areas Volume 9, issue 1, Janvier-Février 2010

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École des hautes études en santé publique (EHESP) Département EST Avenue du professeur Léon Bernard 35043 Rennes cedex, Direction départementale des Affaires sociales des Pyrénées Atlantiques (DDASS) Cité administrativeBoulevard Tourasse 64026 Pau cedexFrance, UFR Sciences et techniques Laboratoire de Chrono-Environnement16, route de Gray25030 Besançon cedexFrance
  • Key words: water pollutants, public policy, water pollution, water supply
  • DOI : 10.1684/ers.2010.0317
  • Page(s) : 71-9
  • Published in: 2010

Although France mandates the definition of catchment protection zones for all drinking water sources, implementation has been delayed in the districts that tap their water from karst areas. The complexity of flow patterns and especially the very high flow velocities through conduits in these aquifers make it difficult to delineate protection zones, which in any case have little if any effect on the episodes of turbidity and microbiological pollution that can affect these waters. It is therefore important to define, even before the protection zones, management tools and water processing methods that will facilitate permanent compliance with quality criteria, including turbidity in the water supply. The size of the inner protection zone must provide an appropriate response time in case of pollution. We propose a longitudinal extension of this zone corresponding to a 2-h transfer time for the fastest flow known for each specific system. The inner protection zone can be completed by satellite protection zones around the sinkholes. The part of the drainage basin not included in the inner protection zone should be the outer protection zone. In this “alert area”, planning measures appropriate to the karstic environments should be applied.