Nitrogen source apportionment for the catchment, estuary, and adjacent coastal waters of the river Scheldt
Vermaat, J.E.; Broekx, S.; Van Eck, B.; Engelen, G.; Hellmann, F.; De Kok, J.L.; Van der Kwast, H.; Maes, J.; Salomons, W.; Van Deursen, W. (2012). Nitrogen source apportionment for the catchment, estuary, and adjacent coastal waters of the river Scheldt. Ecol. Soc. 17(2): 30. http://dx.doi.org/10.5751/ES-04889-170230 In: Ecology and Society. Resilience Alliance Publications: Wolfville, Nova Scotia, Canada. ISSN 1708-3087; e-ISSN 1708-3087, more |   |
| Author keywords | catchment hydrology, coupled modeling, estuary, eutrophication, land use, systems analysis, watershed nutrient loading |
| Authors | | Top | | - Hellmann, F.
- De Kok, J.L., more
- Van der Kwast, H., more
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| Abstract | Using the systems approach framework (SAF), a coupled model suite was developed for simulating land-use decision making in response to nutrient abatement costs and water and nutrient fluxes in the hydrological network of the Scheldt River, and nutrient fluxes in the estuary and adjacent coastal sea. The purpose was to assess the efficiency of different long-term water quality improvement measures in current and future climate and societal settings, targeting nitrogen (N) load reduction. The spatial-dynamic model suite consists of two dynamically linked modules: PCRaster is used for the drainage network and is combined with ExtendSim modules for farming decision making and estuarine N dispersal. Model predictions of annual mean flow and total N concentrations compared well with data available for river and estuary (r² = 0.83). Source apportionment was carried out to societal sectors and administrative regions; both households and agriculture are the major sources of N, with the regions of Flanders and Wallonia contributing most. Load reductions by different measures implemented in the model were comparable (~75% remaining after 30 yr), but costs differed greatly. Increasing domestic sewage connectivity was more effective, at comparatively low cost (47% remaining). The two climate scenarios did not lead to major differences in load compared with the business-as-usual scenario (~88% remaining). Thus, this spatially explicit model of water flow and N fluxes in the Scheldt catchment can be used to compare different long-term policy options for N load reduction to river, estuary, and receiving sea in terms of their effectiveness, cost, and optimal location of implementation. |
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