Co-sponsored by NUON-WATER, Velp, The Netherlands.
During the last decades, nitrate concentrations in recently infiltrated water from infiltration areas in "de Veluwe" have slowly increased. As the dominant vegetation in these infiltration areas is mainly forests, the drinking water company NUON-WATER is very interested in the role of the forests with respect to nitrate leaching. Due to increased atmospheric nitrogen deposition, many forests in the Netherlands are nitrogen saturated. This could have resulted in increased nitrate losses to the groundwater.
In a case study in the 10 km2-infiltration area "Edese bos", nitrate leaching is quantified using a dynamic GIS, consisting of a combination of a GIS and a regional nitrate leaching model called WANDA. The GIS contains information of soil type, tree species, age of the stand, nitrogen deposition and carbon and nitrogen storage in the organic layer of the forest stands. WANDA calculates nitrate leaching as a function of these variables. This dynamic GIS is used for scenario analyses to assess effects of decreased nitrogen deposition, forest management options and changes in landuse.