Department of Nature and Environment The Municipality of Århus Groundwater protection and spatial planning in the Municipality of Århus Niels Cajus Pedersen, M.Sc., Municipality of Århus Birthe Eg Jordt, M.Sc., Orbicon A/S

Department of Nature and Environment The Municipality of Århus Scope The number of citizens and the urban areas is expected to increase significantly in the future. Not only will the need of drinking water to supply the citizens increase but also the risk of groundwater contamination. This presentation will show how the Municipality of Århus has incorporated groundwater protection in the location of new urban areas. Focus on protection of vulnerable groundwater resources

Department of Nature and Environment The Municipality of Århus Area km km 2 Population5.5 mio0.3 mio Population density127 /km /km 2

Department of Nature and Environment The Municipality of Århus Water supply in the Municipality of Århus Facts –Only source of drinking water is groundwater –Yearly consumption approx. 20 mio m 3. –40 water works –180 water supply wells –Groundwater level has been lowered with up to meters due to water abstraction. Political objectives –Treatment of groundwater only by aeration and filtration –Self-sufficient with drinking water within the Municipality

Department of Nature and Environment The Municipality of Århus Water supply in the Municipality of Århus Particularly valuable water abstraction areas Expected to fullfill the future needs for drinking water

Department of Nature and Environment The Municipality of Århus Water supply in the Municipality of Århus 180 water supply wells

Department of Nature and Environment The Municipality of Århus State of the water supply in the Municipality of Århus Groundwater resources are scarce and under pressure A high level of protection is needed, in order to live up to the political objectives

Department of Nature and Environment The Municipality of Århus National Planning Strategy In the Danish national planning strategy from 2006 there was a significant change in the urban development of Denmark Two growth centres in Denmark were now expected to attract most of the development in jobs and housing

Department of Nature and Environment The Municipality of Århus Spatial planning in the Municipality of Århus Strategy for spatial planning in the Municipality of Århus was revised in 2007 according to the national planning strategy The Municipality of Århus is a main part of the western urban region and is expected to increase its number of houses by and inhabitants by in the next 30 years The growth of inhabitants in Århus will take place in both existing urban areas, by increasing population density (higher, more dense) new cities. Expected to be the only way to make sustainable cities. Will be located in the rural area

Department of Nature and Environment The Municipality of Århus Spatial planning in the Municipality of Århus Acitivities in urban areas cause risk of groundwater contamination. A number of water supply wells have been closed due to pollution from xenobiotics (pesticides and chlorinated compounds) Internal guidelines for groundwater protection in the Municipality of Århus for planning and administration have been made: –Location of activities which could pollute groundwater are prohibited or restricted in areas, where groundwater resources are vulnerable and in wellhead protection zones. –The wellhead protection zones cover areas within 300 meter from any water supply well.

Department of Nature and Environment The Municipality of Århus Vulnerability of groundwater resources Vulnerability of aquifers in the Århus area is closely connected to the clay cover above the aquifers. Many contaminants are either degraded or adsorbed in clayrich sediments Clay cover of more than 15 meters above the aquifers seems to give a sufficient protection The clay cover has been mapped geophysically in most of the particularly valuable water abstraction areas

Department of Nature and Environment The Municipality of Århus Vulnerable areas Vulnerable areas has been mapped in most of the particulary valuable water abstraction areas Covers approx. 150 km 2

Department of Nature and Environment The Municipality of Århus Supplementary mapping of vulnerability The supplementary geophysical mapping was conducted in May 2007 The mapping was carried out in areas where new cities were planned, and where the protection of valuable groundwater resources was unknown The geophysical results and the information about the groundwater vulnerability was then used in the ongoing planning process and the location of the new cities.

Department of Nature and Environment The Municipality of Århus Location of new cities

Department of Nature and Environment The Municipality of Århus Location of new cities

Department of Nature and Environment The Municipality of Århus Location of new cities

Department of Nature and Environment The Municipality of Århus Location of new cities

Department of Nature and Environment The Municipality of Århus Location of new cities

Department of Nature and Environment The Municipality of Århus Future planning – Recreational zones Recreational zones of 1,5 km around the new cities Integration of recreational and environmental considerations

Department of Nature and Environment The Municipality of Århus Future planning New city Forest Wetlands Tracks

Department of Nature and Environment The Municipality of Århus Conclusion This case has shown how results from geophysical mapping and the knowledge about vulnerabilty have been used in the present planning proces Supplementary geophysical mapping was done during the planning proces to improve the decisionmaking process Location of future urban areas has to a large extent been adapted to the vulnerability of the groundwater