Ecological effects of water management in the Netherlands: The model DEMNAT

Abstract

In the Netherlands extensive drainage of agricultural land and extraction of groundwater has caused a structural lowering of the phreatic groundwater level as well as a decreasing influence of upward seepage in the root zone of the soil with negative consequences for most groundwater-dependent ecosystems. In Dutch, this environmental stress is known as 'verdroging'. The English term most frequently used is desiccation, but here the term is used with a broader interpretation, to include changes in (soil)water quality due to groundwater depletion. Since the late 1980s desiccation has been recognised by the Dutch government as a major environmental problem. As part of the development of abatement strategies various models have been built. These models are used to analyse the consequences of different water management scenarios for separate landuse functions, such as agriculture, shipping and public water supply. In order to account for the natural environment in these analyses the national ecohydrological model DEMNAT (Dose Effect Model NAture Terrestrial) was developed. A brief description is given of the latest model version. Moreover, results are discussed based on recent applications at national, regional, as well as local scales. Some perspectives for future model developments are discussed. (C) 2000 Elsevier Science B.V.