title: Modeling flow and nitrate fate at catchment scale in Brittany (France).
abstract: In the intensive pig-farming (Sus scrofa) area of Brittany (western France), many surface and subsurface water resources are contaminated by nitrate (NO3) with concentrations that chronically exceed the European Community 50 mg L(-1) drinking standard. To ensure sustainable water supply, the fate of NO3 must be considered in both surface water and ground water. The fate of N was investigated in a Britain catchment, the Coët-Dan watershed, with an integrated management tool: the hydrological SWAT model coupled with the ground water model MODFLOW, and its companion contaminant and solute transport model MT3DMS. The model was validated with respect to water quantity during a 6-yr period and for the NO3 concentration during a 44-mo period, at two gauging stations in the catchment. The coupled models reproduced accurately the measurements. At the basin outlet, the Nash-Sutcliffe coefficients were 0.88 for monthly flow for the entire period and 0.87 for monthly N load. Alternative scenarios were simulated and showed potential benefits of decreasing manure application from 210 to 170 kg N ha(-1) as required by the European Commission Nitrates Directive.
authors.affiliation: Joint Research Centre of the European Commission, Inst. for Environment and Sustainability, Soil and Waste Unit, TP 460, 21020 Ispra (VA), Italy. conan@eau-rhin-meuse.fr
authors.forename: Céline
authors.initials: C
authors.lastname: Conan
authors.forename: Fayçal
authors.initials: F
authors.lastname: Bouraoui
authors.forename: Nadine
authors.initials: N
authors.lastname: Turpin
authors.forename: Ghislain
authors.initials: G
authors.lastname: de Marsily
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bidoglio
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D005602:France; D006801:Humans; D008962:Models, Theoretical; D009566:Nitrates / Q000032:analysis* / Q000737:chemistry; D013552:Swine; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical