The supply of drinking water in Denmark is based on high-quality groundwater resources. The authorities are in the process of identifying the areas from where we will be getting this water in the future.
GEUS’ activities in brief
As a specialist data centre, GEUS assists the Danish Nature Agency in the national groundwater mapping and in safeguarding that data and results collected are properly stored in GEUS’ databases and can be put to use in water resources management in the future. This assistance also includes specialist consultancy services, as well as development of standards and geoguidelines to standardise and improve the efficiency of groundwater mapping at a high, professional level. Geoguidelines have been prepared on topics such as groundwater potential mapping, hydrological modelling, geological model creation, mapping of chalk reservoirs, and assessments of the vulnerability of groundwater aquifers to nitrates.
Geophysical measurements are an important aspect of groundwater mapping. GEUS and the Danish Nature Agency are involved in a collaboration with Aarhus University to optimise the use of, and to further develop, geophysical methods in national groundwater mapping, e.g. helicopter-borne SkyTEM measurements. GEUS provides input to guidelines on how to carry out geophysical measurements, including how to process and interpret these.
In connection with national groundwater mapping, GEUS is responsible for running databases of geological models and reports containing information on the geology of Denmark, as well as the GERDA database, which contains large quantities of geophysical data from groundwater mapping activities.
Geology in 3D
GEUS conduct research and development within 3D geological modelling
and has established detailed 3D geological models for several areas throughout Denmark. The models integrate borehole data, geophysical (especially airborne and seismic data) and geochemical data with geological mapping and other geological information and knowledge. The models are typically targeted groundwater flow modelling, but since they are basically build as multi purpose models, they can be applied in other relations.
National water resources mapping
GEUS runs and develops a national water resources model, the so-called DK-model, which is used to estimate the exploitable water resources available for water supply. The model describes both groundwater and surface water flows. The DK-model is a large-scale model, which calculates the overall water balance as well as the degree of utilisation and extent of the groundwater resources, taking into account the climate, land use and current water abstraction strategies. GEUS’ vision for development of the model is that it should be a common reference framework for national work on mapping, monitoring and management of Danish water resources.
Identification of areas sensitive to pesticides
Concurrently with national groundwater mapping activities, GEUS has been looking into whether it is possible to identify areas that are particularly sensitive to pesticide leaching to the groundwater. These efforts, launched as a part of the Government's Pesticides Plan II, have been conducted in collaboration with the Department of Agroecology at Aarhus University. Conclusions, so far, indicate it is possible to identify sandy soils that are particularly sensitive to pesticides, whereas the work on clay soils is pending further study.