title: Successful reduction of diffuse nitrogen emissions at catchment scale: example from the pilot River Odense, Denmark.
abstract: Land-based total nitrogen (N) loadings to Danish coastal waters have been markedly reduced since 2000. This has been achieved by general measures reducing discharges from all point sources and N leaching from farmed land supplemented with more local and targeted mitigation measures such as restoration of wetlands to increase the catchment-specific N retention. In the catchment of River Odense, restoration of wetlands has been extensive. Thus, in the major gauged catchment (485 km(2)) eleven wetlands (860 ha) have been restored since 2000. A comparison of data on N concentrations and loss from a gauging station in the River Odense with data from a control catchment (772 km(2)), in which a significantly less intensive wetland restoration programme has been undertaken, showed an excess downward trend in N, amounting to 124 t N yr(-1), which can be ascribed to the intensive wetland restoration programme carried out in the River Odense catchment. In total, the N load in the River Odense has been reduced by 377 t N yr(-1) (39%) since 2000. The observed downward trend is supported by monitoring data from two wetlands restored in 2001 and 2004 in the River Odense catchment.
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: J
authors.initials: J
authors.lastname: Windolf
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: H
authors.initials: H
authors.lastname: Tornbjerg
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: C C
authors.initials: CC
authors.lastname: Hoffmann
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: J R
authors.initials: JR
authors.lastname: Poulsen
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: G
authors.initials: G
authors.lastname: Blicher-Mathiesen
authors.affiliation: Department of Bioscience and DCE - National Centre of Environment and Energy, Aarhus University, Vejlsøvej 25, DK-8600 Silkeborg, Denmark E-mail: jwn@bios.au.dk.
authors.forename: B
authors.initials: B
authors.lastname: Kronvang
mesh_terms: D003718:Denmark; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation; D009584:Nitrogen / Q000032:analysis*; D045483:Rivers / Q000737:chemistry*; D053833:Wetlands
chemical_list: D009584:Nitrogen