National monitoring of Danish groundwater resources, operation of the Danish Pesticide Leaching Assessment Programme and national water resources modelling.
GEUS’ activities in brief
Groundwater monitoring in Denmark is primarily to protect the security of supply of drinking water, which is based almost exclusively on groundwater resources. Consequently, there is a special need to monitor and protect groundwater. However, the quality of groundwater can also greatly affect the quality of freshwater on the surface particular in watercourses.
In this context, GEUS is involved in national groundwater monitoring, in the Danish Pesticide Leaching Assessment Programme and in national water resources modelling.
Groundwater quality is monitored in the GRUMO programme through a series of special monitoring wells from which samples are taken each year. These samples are examined for substances such as nitrates, pesticides, chlorides, arsenic and organic pollutants. Groundwater quantity is monitored through the National Groundwater Level Monitoring Programme, which includes several daily measurements of groundwater levels throughout Denmark. The local units under the Danish Nature Agency are collecting this data. Furthermore, results from the waterworks well control analyses and information about the quantities of water pumped up are also used.
GEUS is the specialist data centre for groundwater and wells, and this entails providing expert advice on monitoring, including preparing annual status reports and technical instructions. Groundwater monitoring is part of the national programme for monitoring the aquatic environment and nature, NOVANA.
The Danish Pesticide Leaching Assessment Programme (VAP)
VAP is a monitoring programme to investigate whether approved pesticides or their degradation products leach into young groundwater in concentrations above the limit value. VAP enables rapid assessment and possible removal of otherwise approved pesticides from the market, if such pesticides prove able to leach into the groundwater during normal use. VAP today consists of five test fields, where correct agricultural practices are used. The fields represent the varying soil and climate conditions in Denmark, and are instrumental for monitoring the destiny of pesticides and their degradation products from the surface, through the soil column and until they end in drains and groundwater. VAP is managed collaboratively between GEUS, the Danish Environmental Protection Agency, as well as the Department of Agroecology and the Department of Bioscience under Aarhus University.
National water resources monitoring
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 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. The model describes both the groundwater flows and the surface water, and it therefore supports work on implementing the EU Water Framework Directive, which requires groundwater and surface water to be managed together.