A METHOD FOR QUANTIFYING THE EFFECTS OF GROUNDWATER SHORTAGES ON AQUATIC AND WET ECOSYSTEMS

This paper describes a method for quantifying the effects of groundwat er shortages or parching on aquatic and wet ecosystems. Linear relatio ns are determined between hydrological indicators and the degree to wh ich ecosystems are parched. The degree of parching is expressed as a n umber between 0 (not affected) and 1 (fully affected). The method take s into account the following processes: lowering of water tables, decr easing intensity of upward seepage, increasing water table fluctuation s and inflow of allochthonous surface water. It enables the degree of parching to be determined annually. The method was developed by the TN O Institute of Applied Geoscience and the Centre of Environmental Stud ies Leiden at the request of the Dutch government, which wishes to eva luate the effect of its environmental policy annually. It can also be used to monitor nature reserves on a local scale.