2.3. Denmark

2.3.1. Characteristics of Groundwater

The Danish Groundwater resources are mainly situated in porous media. All regions combined have an area of 43,216 km² i.e. 99.9% of the national Danish territory. The resources in porous media can be divided in Quaternary sand and gravel deposit areas, in Miocene sand and gravel deposit areas and in chalk deposits. The most important potential water resource is precipitation (30,500 mio. m³/year). The evapo-transpiration is about 18,000 mio. m³/year. In Denmark 420 mio. m³/year of water are consumed by households, 225 mio. m³/year by industry and 400 mio. m³/year by agriculture. Denmark is able to gain 99% of the drinking water out of groundwater resources in porous aquifer.

2.3.2. Structure of the Administrative Organisations Concerning Groundwater Quality

Denmark has a nation-wide groundwater quality monitoring network. The head structure for all monitoring activities is the Danish Parliament the „Folketing" that makes the laws and ordinances and among them groundwater legal obligations. The „Fagdatacentre", the national Danish data centre, that is composed of different „Institutions" such as GEUS (DGU changed to GEUS Geological Survey of Denmark and Greenland) and DMU the former NERI. GEUS is the national data centre for groundwater quality and quantity monitoring that is responsible for the scientific content of the groundwater monitoring programme, the organisation of the programme, the evaluation of data and for reporting. The EPA is an administrative unit under the Ministry of Environment and Energy, that is responsible -as an executive body- to co-ordinate the whole groundwater monitoring programme „Aquatic Environment Nationwide Monitoring Programme" and provide the annual status of the programme. The 14 Danish counties (and 2 municipalities with „county"-status) are responsible for the data collection, data evaluation and the regional reporting. The counties send all data and reports to the Fagdatacentre, groundwater data to GEUS, surface water data to DMU.

The people’s supply of drinking water and therefore the collection of groundwater/drinking quality data differs a bit from the monitoring aforesaid structures. If groundwater is used as drinking water the 14 Danish counties (and 2 municipalities with „county"-status) are obliged to collect groundwater data and send them to GEUS. The 275 municipal units are responsible for the drinking water supply with respect to quality standards. The main objective for the network is to monitor groundwater quality in relation to land use and point sources. In addition the obtained quality data are also used for research and scientific work and for information to the general public.

2.3.3. Monitoring of Groundwater Quality

The Danish Groundwater quality monitoring programme (VAMP) covers the whole country. Quality data are observed by 1,100 sampling sites which were distributed under the consideration of monitoring all geological and hydrological settings in Denmark. Near half of these sampling sites are special wells for observation purpose. The main type (1,090) of the stations is a characterisation station to get the average situation of groundwater in the region.

Parameters observed are sampled between 2-4 times a year. They contain a number of physical descriptive parameters (pH, total hardness, temperature...), as well as major ions (calcium, nitrate, ammonium..), heavy metals (zinc, lead, cadmium..) or pesticides. Hydrochlorinated carbons and pesticides are sampled every other year. The analysing is made by 15 different private laboratories which are obliged to follow the „Danish Standard" for laboratory work. Scientific inspectors as well as county control are additional measurements for quality control and assurance methods. Raw data in a (digital) RDBMS by using a VAX (VMS) and PCs (Windows/DOS). Language, software, query and reporting tools are SQL, SAS, Datatrieve and Smartstar. Since 1989 computerised data have been available on floppy disks, paper sheets or reports. Data are available without restrictions but not free of charge at the Danish Geological Survey of Denmark and Greenland (GEUS). The GEUS is also responsible for publishing a yearbook about groundwater quality data. The target audience are the Danish Parliament and the general public.  

2.3.4. Structure of the Administrative Organisations Concerning Groundwater Quantity

Data about groundwater quantity (pumping rates) are collected by all waterworks, industries with own water supply and municipalities. The data are evaluated and stored by the municipalities and the 14 Danish counties (and 2 municipalities with „county"-status). Summarised data are sent to GEUS. The Counties and GEUS produce the annual report about the groundwater consumption. There are local networks (run by water works), regional networks (run by Counties) and a national network (run by GEUS) for groundwater level monitoring. The Counties also plan the regional use of groundwater in the different sectors such as households, industry or irrigation. The counties give license to larger groundwater abstractions and the municipalities give license to minor groundwater abstractions.

2.3.5. Monitoring of Groundwater Quantity

The Danish groundwater observation network is spread over the whole country. That means that there are 200 observation points distributed in an area of 43,216 km²; thereupon the sampling site density is about 0.5/100 km² in porous media. Most of the observation points are bored wells with indication of altitude and co-ordinates. These sampling sites observe the water level with a monthly frequency. The network has been in operation since 1950. Data stored refer to water level as well as ground level, co-ordinates and date of record. Data are loaded on to a digital RDBMS or a MS-ACCESS, by using VAX, VMS or Digital. Language, software, query and reporting tools are SAS, DATATRIEVE. The Geological Survey of Denmark and Greenland (GEUS) is responsible for data management. Data can be made available on floppy disks, paper sheets or reports. There are no restrictions but a fee has to be paid.

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