2.15.1. Characteristics of Groundwater
The main aquifers are found in glacifluvial sand and gravel deposits. They cover only a few parts of Swedish territory, although more than three quarter of the Swedish population is supplied with drinking water from these resources. Till, another porous aquifer, covers 75 % of the country. Occasionally good yields can be achieved from these deposits, but wells in this area are mainly for single household supply. Aquifers in porous sedimentary rock are found in south-west of Sweden. They are very small regions as compared to the whole Swedish area. Karst groundwater is rare in Sweden. Aquifers in Archaean bedrock area have the largest extent of all aquifers. They can be found all over the country. Wells drilled in these rock types seldom yield more than 1l/s and are mainly for private water supply for single households.
2.15.2. Structure of the Administrative Organisations Concerning Groundwater Quality
The Ministry for Industry finances the Geological Survey of Sweden which is responsible for groundwater monitoring networks on a national level. Additionally the SGU is also responsible for environmental groundwater monitoring and produces reports and manuals on that topic that are delivered to the Environmental Protection Agency (EPA). The EPA is an organisation under the Ministry for Environment, which finances this kind of monitoring network. Databases on groundwater chemistry of both network systems are run and managed by the SGU. The 24 Swedish county authorities collect regional and local monitoring data -in co-operation with municipalities- and send them to the SGU. The SGU provides a handbook for sampling methodology, reports and data from the national database for them.
The main purposes for monitoring are:
the description of environmental status and the detection of changes caused by anthropogenic load (acidification, Eutrophication, heavy metals)
the assessment of the threat by anthropogenic load on groundwater quality as a basis for the formulation of environmental goals and on decisions on measurements (national and international) to achieve the goals.
The monitoring complies with national standards as the outline of the monitoring. Chemical analyses are made according to Swedish standards which usually agree with international standards. Integrated monitoring is carried out according to international standards. Quality assurance is determined by sampling methods according to manuals. Analyses are made by authorised laboratories. A complete set of variables allows ion balance control.
2.15.3. Monitoring of Groundwater Quality
The Country Wide Environmental Monitoring of Groundwater in Forest Ecosystems" undertakes monitoring activities in order to describe the environmental status and to reveal changes caused by anthropogenic load such as acidification, Eutrophication, heavy metals. The observation of water quality is a basis for the formulation of environmental goals and helps to decide measurements on both national and international level to achieve these goals. The Geological Survey of Sweden co-ordinates the whole monitoring programme and manages the network database and carries out reports. The SGU is supported by the Swedish counties that organise the local sampling of data with their regional programmes. Sampling sites are distributed taking account of the heterogeneity of the geology of Sweden. Two sampling sites are operating in each of the 27 different geological regions of Sweden.
Groundwater data are analysed by 2 public laboratories. The sampling methodology is standardised, as follows: 1) the material of observation tubes is polythene. 2) the sampling equipment is of inert material, 3) turnover of water before sampling, 4) polythene bottles for heavy metals are washed in strong acids, 5) filtering of samples before acid preservation -acid washed 0.45 µ membrane filter and finally 6) transport of samples in cool boxes. In the laboratories the quality control and assurance procedures are ion balance control, control of individual variables and internal laboratory control. Data are stored in a RDBMS database (MIMER) using PCs, main frame computers and SUN workstations. Reporting, software tools are SAS and SQL. Computerised data have been available since 1979. Data can be made available on floppy disks, paper sheets and reports. Data have to be paid for, but are not restricted. The SGU publishes the annual reports for e.g. county authorities or environmental agencies.
2.15.4. Structure of the Administrative Organisations Concerning Groundwater Quantity
The Swedish Ministry for Industry provides the financial basis for the Swedish Geological Survey (SGU). This is the responsible organisation for the database management within the groundwater quantity networks. The network is a national reference network. Local networks are connected with municipal water works. There is no connection between them and the national network, but the national one serves as a reference to the local ones. Quality assurance is done by manual checking of time series.
The objectives for the groundwater network are:
Study of regional and temporal variations of groundwater quality and quantity in relation to geology, topography and climate for groundwater resource estimation, reference purposes, forecasting and environment monitoring.
The SGU co-ordinates the monitoring activities and publishes the reports. Mass media agencies and subscribers of the information are monthly supplied with the reports.
2.15.5. Monitoring of Groundwater Quantity
The Swedish National Groundwater Network aims at studying temporal variations of groundwater quantity and quality in relation to geology, topography and climate. This should be a basis for groundwater resource estimation, reference purposes, forecasting and environmental monitoring. The responsible organisation is the Swedish Geological Survey (SGU) which co-ordinates the programme. In porous media 357 sampling sites are distributed in order to collect water level and temperature data. The majority of them are driven wells. The methodology of observation is standardised. Local observers manually measure the depth of the groundwater level twice a month and e-mail the result to SGU. Approximately 50 observers telephone the result of mid-month observations to a telephone recorder at the SGU on the day of observation. Quality control and assurance procedures are undertaken by intermittent manual control
The network has been in operation since 1955, the average length of record is approximately 20 years. Data are stored in a RDBMS database (MIMER) using PCs, main frame computers and SUN workstations. Reporting, software tools are SAS and SQL. Computerised data have been available since 1979. Data can be made available on floppy disks, internet, paper sheets and reports. The extraction of data is not free of charge whereas the data itself is not restricted. The SGU publishes reports about groundwater quantity monitoring.
For references, please go to http://www.eea.europa.eu/publications/92-9167-032-4/page017.html or scan the QR code.
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