Edit project overview: Case study:Dam removal at Grönkullen, River Rolfsån

Please enter a description of the project: Grönkullen hydro power station is located in one of the upstream tributaries of River Rolfså, River Sörån. Restorations took place after the county administrative board wanted to make migration possible for lake dwelling brown trout in lake Lygnern. Because a chemical plant and a railway are situated next to the river and there is a possible concentration of chemicals in the river, investigations were accomplished to find out whether the dam removal has any effect to the stability conditions. Conclusion was that there would not be any significant effect of the dam removal to the stability or water levels of the river. Investigations were made in 2002-2004 and the municipality of Bollebygds bought the plant 2005 to be able to remove the dam. Restoration was done in 2005. A new river was rebuilt upstream and downstream of the old dam, altogether along a 200 m stretch. A small part of the old dam was saved as a reminder of how it once was. Stones and gravel were added to the river bank. Total cost of the restoration was about 5 million Swedish crones (ca. 500 000 euros).

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Lessons learnt: