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Groundwater pollution remediation and protection 269

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The Drastrup Project, north Jutland, Denmark
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A unique example of spatial planning to achieve sustainable land cover with low intensity grazing (Fig. 1). Planting began in the late
use in a groundwater catchment area with the aim of improving 1990s and the new forest was inaugurated in September 2001
and protecting groundwater quality is provided by the Drastrup (Municipality of Aalborg 2001).
Project in north Jutland, Denmark. The motivation for the project The initial preparation of soil in the new forest area by deep
was decreasing water quality from the diffuse input of nitrate and ploughing caused an initial flush of nitrate (up to 40 mg L −1 as N)
pesticides, with concentrations of nitrate up to 125 mg L −1 in but it is considered that as the trees grow, soil nitrate concentra-
groundwater. The Drastrup area, covering about 870 ha, is one tions will begin to decline after 4–6 years. Trees demand a high
of two large groundwater catchment areas for the city of Aalborg, nitrogen uptake during the first 15 years of growth, and so effect-
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contributing 20%, or approximately 1.7 × 10 m , of the annual ively reduce soil nitrate leaching, but later soil nitrate concentra-
municipal water supply demand (Fig. 1). tions may increase as a result of atmospheric inputs of nitrogen to
To protect the underlying Chalk aquifer and demonstrate the the ageing forest canopy. In areas of grassland, soil monitoring
effects of land use change on nitrate leaching, it was decided to has shown that conversion to grassland quickly reduces nitrate
apply a municipal planning act to execute voluntary land distribu- concentrations to effectively zero within the first 2–3 years of con-
tion among farmers in the groundwater catchment area near Frejlev version (Fig. 2a).
and Drastrup. The farm owners received compensation in the form Since the implementation of land-use change in 1994, depth
of either payments or as land outside of the groundwater catch- sampling of groundwater may now be showing signs of improve-
ment area. The project also had the objective of establishing a ment in water quality, although further years of monitoring
recreational area close to Aalborg for the benefit of its citizens are required to identify unambiguously an improvement in water
through the creation of a new, 230-ha recreational forest compris- quality from natural background variation in nitrate content
ing a non-rotation, mixed age forest with some permanent grass (Fig. 2b).

Fig. 1 The Drastrup area, Denmark, showing the area of new forest planted to protect groundwater from the leaching of nitrate.
After the Municipality of Aalborg (2001).