Use of geochemistry in groundwater vulnerability mapping in Denmark

The principal aim of mapping ground-water vulnerability in Denmark is to ensure optimal protection of present and future drinking-water resources. Groundwater vulnerability mapping of areas up to 1000 km² has been taking place over the past seven years. The scale of mapping has been adjusted to meet the demands for details of regulation of land use requested by Danish legislation. Groundwater vulnerability mapping comprises analyses and integration of geological, geophysical, hydrological and geochemical data. This paper focuses on the geochemical reactions between groundwater and sediment. Geochemical knowledge may sometimes not be fully and systematically utilised in groundwater vulnerability mapping. This paper presents different geochemical approaches and demonstrates how these can be successfully integrated with geological, geophysical and hydrological data.