Difference between revisions of "Case study:Restoration of the river Børselva"

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|Multi-site=No
 
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|Project picture=Borselva.jpg
 
|Project picture=Borselva.jpg
|Project summary=Condition in 1999 - before measures: Siltation and overgrowth of macrophytes due to greatly reduced water flow (hydropower regulation) and drainage from agriculture. Very poor conditions for fish and other aquatic organisms. Nearly 70% of the water area in Børselva was covered by plants. Important wetland biotopes for wetland birds were about to disappear. Large parts of the trout’s spawning and growing areas were destroyed.
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|Project summary=In 1999, before the measures were carried out, there was siltation and overgrowth of macrophytes due to the greatly reduced water flow (hydropower regulation) and drainage from agriculture. 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 about to disappear. Large areas of trout spawning and growing areas were destroyed.
  
Measures implemented: Measures in the agricultural channel ("Bruksåskanalen"): Erosion control, establishment of sedimentation ponds with vegetation filters and revegetation along the channel. Establishment of three paved thresholds in Børselva, laying of spawning gravel. 1 km of the overgrown part of the river was opened with an excavator and by laying of fiber fabric with stone and gravel on top. Dredging and opening of the rest of the Børselva with a large excavator ("Langemann"). Testing of different water discharges in Børselva (from the dam in Børsvatnet) - main focus on “flushing floods” and winter water flow.
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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 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.
  
 
Condition in 2019 – after measures: Studies show major environmental improvements, but the environmental objectives of good chemical status and good ecological potential have not yet been achieved. 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).
 
Condition in 2019 – after measures: Studies show major environmental improvements, but the environmental objectives of good chemical status and good ecological potential have not yet been achieved. 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).

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Location: 68° 18' 14", 16° 42' 48"
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Project overview

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Status In progress
Project web site
Themes Habitat and biodiversity, Hydropower, Hydromorphology, Land use management - agriculture
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 picture

Project summary

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In 1999, before the measures were carried out, there was siltation and overgrowth of macrophytes due to the greatly reduced water flow (hydropower regulation) and drainage from agriculture. 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 about to disappear. 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 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.

Condition in 2019 – after measures: Studies show major environmental improvements, but the environmental objectives of good chemical status and good ecological potential have not yet been achieved. 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).

Monitoring surveys and results

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www.fylkesmannen.no/contentassets/74f02cdd90cb485ea8def16785a345d3/ballangen---borselva---2016---etterundersokelser-etter-restaureringstiltak---vannvegetasjon-og-fisk---niva-rapp-7083-2016.pdf

Lessons learnt

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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


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Catchment and subcatchment



Site

Name Børselva
WFD water body codes 172-5-R (EU-ID:NO172-5-R)
WFD (national) typology RNM2321
WFD water body name Børselva
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body No
National/international site designation Norway - Naturreservat
Local/regional site designations National Reserve
Protected species present Yes
Invasive species present No
Species of interest
Dominant hydrology Artificially regulated
Dominant substrate
River corridor land use Broadleaf/mixed woodland (semi natural), Improved/semi-improved grassland/pasture, Wetland, Tall herb/rank vegetation
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) 0.15
0.15 m³/s
150 l/s
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m)
Project started 1997/01/01
Works started
Works completed
Project completed
Total cost category 100 - 500 k€
Total cost (k€) 296
296 k€
296,000 €
Benefit to cost ratio
Funding sources Ballangen Energi AS, The Norwegian Water Resources and Energy Directorate (NVE)

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
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 Hydropower, Land drainage
Hydromorphology
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications Cut back of plants, Introduction of spawning gravels, Creation of mini-treshold, Creation of pools, sediment, Sediment trap building
Floodplain / River corridor Erosion protection
Planform / Channel pattern
Other
Non-structural measures
Management interventions Reduced pollution, Flow management
Social measures (incl. engagement)
Other


Monitoring

Hydromorphological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Fish Yes Yes No No No

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative

Any other monitoring, e.g. social, economic

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative


Monitoring documents



Additional documents and videos


Additional links and references

Link Description
http://www.fylkesmannen.no/contentassets/74f02cdd90cb485ea8def16785a345d3/ballangen---borselva---2016---etterundersokelser-etter-restaureringstiltak---vannvegetasjon-og-fisk---niva-rapp-7083-2016.pdf Report
http://faktaark.naturbase.no/?id=VV00000213
http://felles.naturbase.no/api/dokument/hent/18653.PDF

Supplementary Information

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