Case study:Dam removal at Grönkullen, River Rolfsån
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Project overview
Status | Complete |
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Project web site | |
Themes | Fisheries, Habitat and biodiversity, Hydropower |
Country | Sweden |
Main contact forename | Andreas |
Main contact surname | Bäckstrand |
Main contact user ID | |
Contact organisation | Länsstyrelsen västra Götalands län |
Contact organisation web site | http://projektwebbar.lansstyrelsen.se/rolfsan/Sv/folj-atgardsarbetet/Pages/soran.aspx?keyword=gr%C3%B6nkullen |
Partner organisations | |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
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 there is a chemical plant and a railway situated next to the river and there is possible consentrations of the chemical in the river investigations were accomplished to find out weather the dam removal has any affection to the stability conditions. Conclusion was that there would not be any significant affection of the dam removal to the stability or water levels of the river. Investigations were made in 2004-2005 and the municipality of Bollebygds bought the plant to ba able to remove the dam. Restoration was done in 2005. Stones and gravel were added to the river bank along a 200 meter stretch and small part of the dam was saved. Total cost of the restoration was about 600 000 euros.
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)
Catchment
River basin district | Skagerrak and Kattegat River basin |
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River basin | Rolfsån River Basin |
Subcatchment
River name | River Rolfsån |
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Area category | |
Area (km2) | |
Maximum altitude category | |
Maximum altitude (m) | |
Dominant geology | Organic (i.e. Peat) |
Ecoregion | Fenno-Scandian Shield |
Dominant land cover | Woodland, Intensive agriculture (arable) |
Waterbody ID |
Other case studies in this subcatchment: Apelnäs fishway at River Rolfså, Biologisk återställning i Rolfsåns vattensystem, Bosgården nature-like fishway at River Rolfså, Restorations of River Nolån-Hulta dam removal, ´Restorations of River Nolån-Bypass channel in Hulta Hydro power plant, ´Restorations of River Nolån-Fishway in Forsa hydro power plant, Ålgårda nature-like bypass channel at River Rolfsån
Site
Name | Grönkullen hydro power station |
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WFD water body codes | |
WFD (national) typology | |
WFD water body name | River Sörån |
Pre-project morphology | Artificial bed, Artificial channel, Embanked, Over deepened, Over-widened |
Reference morphology | |
Desired post project morphology | |
Heavily modified water body | Yes |
National/international site designation | |
Local/regional site designations | |
Protected species present | No |
Invasive species present | No |
Species of interest | Lake dwelling brown trout |
Dominant hydrology | Artificially regulated |
Dominant substrate | |
River corridor land use | Woodland |
Average bankfull channel width category | |
Average bankfull channel width (m) | |
Average bankfull channel depth category | |
Average bankfull channel depth (m) | |
Mean discharge category | |
Mean annual discharge (m3/s) | |
Average channel gradient category | |
Average channel gradient | |
Average unit stream power (W/m2) |
Project background
Reach length directly affected (m) | 200200 m <br />0.2 km <br />20,000 cm <br /> |
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Project started | 2002 |
Works started | 2005/08/01 |
Works completed | 2005/10/31 |
Project completed | 2005/10/31 |
Total cost category | 500 - 1000 k€ |
Total cost (k€) | 600600 k€ <br />600,000 € <br /> |
Benefit to cost ratio | |
Funding sources |
Cost for project phases
Phase | cost category | cost exact (k€) | Lead organisation | Contact forename | Contact surname |
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Investigation and design | |||||
Stakeholder engagement and communication | |||||
Works and works supervision | |||||
Post-project management and maintenance | |||||
Monitoring |
Reasons for river restoration
Mitigation of a pressure | Barriers to fish migration, Hydropower |
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Hydromorphology | Continuity for organisms, Quantity & dynamics of flow |
Biology | Fish |
Physico-chemical | |
Other reasons for the project |
Measures
Structural measures
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Bank/bed modifications | Barriers removal, Bed-raising |
Floodplain / River corridor | |
Planform / Channel pattern | |
Other | |
Non-structural measures
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Management interventions | |
Social measures (incl. engagement) | |
Other |
Monitoring
Hydromorphological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative |
Biological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative |
Physico-chemical quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative |
Any other monitoring, e.g. social, economic
Element | When monitored | Type of monitoring | Control site used | Result | ||
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Before measures | After measures | Qualitative | Quantitative |
Monitoring documents
Image gallery
Additional documents and videos
Additional links and references
Link | Description |
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Supplementary Information
Edit Supplementary Information