Case study:Restoration of the river Børselva: Difference between revisions
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Latest revision as of 09:12, 25 February 2020
Project overview
Status | In progress |
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Project web site | http://www.borselva.no/bakgrunn/bakgrunn.php |
Themes | Fisheries, Habitat and biodiversity, Hydropower, Hydromorphology, Land use management - agriculture, Monitoring |
Country | Norway |
Main contact forename | Lars |
Main contact surname | Sæter |
Main contact user ID | |
Contact organisation | County Governor of Nordland |
Contact organisation web site | http://www.fylkesmannen.no/nordland |
Partner organisations | The Norwegian Water Resources and Energy Directorate (NVE), Ballangen Energi AS, Norwegian Institute for Water Research (NIVA) |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
In 1999, before the measures were carried out, there were problems with siltation and overgrowth of macrophytes in the river channel, due to the greatly reduced water flow resulting from hydropower production and agricultural drainage. There were very poor conditions for fish and other aquatic organisms. Nearly 70% of the water area in Børselva was covered by plants. Important habitats for wetland birds were in danger of disappearing. Large areas of trout spawning and growing areas were destroyed.
Measures implemented in the agricultural channel ("Bruksåskanalen") included erosion control, establishment of sedimentation ponds with vegetation filters and revegetation along the channel. Three paved thresholds were established in Børselva, with the laying of spawning gravel. 1 km of the overgrown part of the river was opened with an excavator and fiber fabric was laid, with stone and gravel on top. Dredging and opening of the rest of the Børselva with a large excavator ("Langemann") was carried out. Different water discharges in Børselva (from the dam in Børsvatnet) were tested - with the main focus on “flushing floods” and winter water flow.
Monitoring surveys and results
The condition in 2019 after the rehabilitation work showed major environmental improvements, but the environmental objectives of good chemical status and good ecological potential have not yet been reached. Further measures are required to reduce agricultural runoff and to implement the final regime for environmentally based water discharges. As of 2019, the hydroelectric license is under review at NVE (The Norwegian Water Resources and Energy Directorate).
Litterature e.g.: www.fylkesmannen.no/contentassets/74f02cdd90cb485ea8def16785a345d3/ballangen---borselva---2016---etterundersokelser-etter-restaureringstiltak---vannvegetasjon-og-fisk---niva-rapp-7083-2016.pdf
Lessons learnt
The measures in the Børselva watercourse (Børselvvassdraget) have created better water quality and hydrological continuity (open water flow) in the formerly overgrown watercourse. The flow levels have improved, self-cleaning has improved and pollution has been reduced. This has resulted in a more varied benthic fauna, better spawning and growing conditions for the trout and improved conditions for the bird fauna.
Image gallery
Catchment and subcatchment
Site
Project background
Cost for project phases
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Any other monitoring, e.g. social, economic
Monitoring documents
Additional documents and videos
Additional links and referencesSupplementary InformationEdit Supplementary Information
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