Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 7 1 2003 10.5194/hess-7-33-2003 http://www.hydrol-earth-syst-sci.net/7/33/2003/ http://www.hydrol-earth-syst-sci.net/7/33/2003/hess-7-33-2003.html http://www.hydrol-earth-syst-sci.net/7/33/2003/hess-7-33-2003.pdf 33 42 0000-00-00 Characterising and modelling groundwater discharge in anagricultural wetland on the French Atlantic coast Ph. Weng F. Giraud P. Fleury C. Chevallier Bureau de Recherches Géologiques et Minières, Service EAU/RMD, 1039 rue de Pinville, 34000 Montpellier, France INRA-SAD, 545, rue Bois Maché,17450 Saint-Laurent-de-la-Prée, France E-mail for corresponding author: p.weng@brgm.fr Interaction between a wetland and its surrounding aquifer was studied in the Rochefort agricultural marsh (150 km²). Groundwater discharge in the marsh was measured with a network of nested piezometers. Hydrological modelling of the wetland showed that a water volume of 770,000 m³ yr^–1 is discharging into the marsh, but that this water flux essentially takes place along the lateral borders of the wetland. However, this natural discharge volume represents only 20% of the artificial freshwater injected each year into the wetland to maintain the water level close to the soil surface. Understanding and quantifying the groundwater component in wetland hydrology is crucial for wetland management and conservation.</b></p> <p style="line-height: 20px;"><b>Keywords: </b>wetland, hydrology, groundwater, modelling, marsh