English Abstract This report describes a procedure to develop a risk
assessment methodology for contaminated sites with respect to the risk of
dispersal in groundwater. The methodology was originally intended for
landfills, but is for example also usable for risk assessment of
contaminated industrial sites and sludge depots or to determine the priority
of remediation. A Geographic Information System database can be constructed
from available databases and preliminary modelling studies, which should
then be ranked according to a fuzzy logic system, and incorporated into a
Decision Support System. The final product, the Decision Support System, is
a flexible instrument for making environmental policy decisions where the
available data is vaguely defined and/or incomplete.