摘要：Using the systems approach framework (SAF), a coupled model suite was developed for simulating land-usedecision making in response to nutrient abatement costs and water and nutrient fluxes in the hydrological network of the ScheldtRiver, 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 andis combined with ExtendSim modules for farming decision making and estuarine N dispersal. Model predictions of annual meanflow and total N concentrations compared well with data available for river and estuary (r2 ≥0.83). Source apportionment wascarried out to societal sectors and administrative regions; both households and agriculture are the major sources of N, with theregions of Flanders and Wallonia contributing most. Load reductions by different measures implemented in the model werecomparable (~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 withthe business-as-usual scenario (~88% remaining). Thus, this spatially explicit model of water flow and N fluxes in the Scheldtcatchment can be used to compare different long-term policy options for N load reduction to river, estuary, and receiving seain terms of their effectiveness, cost, and optimal location of implementation
关键词：catchment hydrology; coupled modeling; estuary; eutrophication; land use; systems analysis; watershed nutrient;loading
