Targeted regulation of nitrogen loads – a spatial modelling case study of a Danish catchment

Berit Hasler1, Line Blok Hansen1 , Maria Konrad 1 ,  Hans Estrup Andersen 2, Mette Termansen1

1 Aarhus University, Dept. of Environmental Sciences, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.

2 Aarhus University, Dept. of Bioscience, Vejlsøvej 25, DK_8600 Silkeborg, Denmark


Nutrient loads cause eutrophication, and the non-point character of this pollution problem has been studied for decades. Efforts have been made to reduce nutrient loads and eutrophication in both Europe and the US, but additional actions are required to achieve good water quality aimed for in water quality policies. Novel data describing the spatial relationships between biophysical, hydrological factors and agricultural production now enable modelling of the non-point pollution and the spatial configuration of costs to reduce these loads. Spatial data have been used to model and analyze the cost-effective choices of abatement measures taking the nonpoint and diffuse distribution of the loads of nitrogen to the sea into account. Applying a cost-minimization model at a fine spatial resolution, we identify spatially distributions of the cost-effective implementation of abatement measures. We conclude that spatially differentiated implementation of abatement measures reduce costs compared to uniform regulations, and that including detailed modelling of the spatial configuration of the nitrogen retention in targeting also enables a reduction of the costs of N abatement.