Case study:Ålgårda nature-like bypass channel at River Rolfsån

Jump to: navigation, search
(0 votes)

To discuss or comment on this case study, please use the discussion page.

Location: 57° 29' 19", 12° 14' 27"
Edit location
Loading map...
Left click to look around in the map, and use the wheel of your mouse to zoom in and out.

Project overview

Edit project overview
Status In progress
Project web site
Themes Fisheries, Habitat and biodiversity, Hydropower
Country Sweden
Main contact forename Andreas
Main contact surname Bäckstrand
Main contact user ID User:Arolam
Contact organisation Länsstyrelsen Västra Götalands län
Contact organisation web site
Partner organisations
Parent multi-site project

Case_study:Biologisk återställning i Rolfsåns vattensystem

This is a parent project
encompassing the following
Ålgårda bypass channel (photo Maria Arola)

Project summary

Edit project overview to modify the project summary.

The watercourse of River Rolfsån is one of the rare inland water areas in Sweden which has vivid salmon and sea trout populations. Besides Atlantic salmon (Salmo salar) and sea trout (Salmo trutta trutta) there are also lake (Salmo trutta lacustris) and stream trout (Salmo trutta fario). Also endangered species freshwater pearl mussel (Margaritifera margaritifera) and European eel (Anguilla anguilla) exist in the watercourse. To maintain these populations the fish need to be able to migrate upstream and downstream. This is why several bypass channels have been built in Rolfså River during last years.

The bypass channel to Ålgårda hydropower plant was finished in October 2012. After the bypass channel has been built, the fish and benthic invertebrates are now able to migrate upstream from the Ålgårda power station. At the same time the hydropower production is ongoing. During winter 2012-2013 also a technical fishway will be finished and by summer 2013 some low sloping bar racks for downstream migration will be completed. In addition a fishery management plan is being prepared in 2013.

Building of a bypass channel is the only option to enable migration for all fauna, also the benthic invertebrates. Bypass channels are also more recommendable than technical fishways because of their contribution to landscape.

Monitoring surveys and results

This case study hasn’t got any Monitoring survey and results, you can add some by editing the project overview.

Lessons learnt

This case study hasn’t got any lessons learnt, you can add some by editing the project overview.

Image gallery

Ålgårda Hyro power plant (photo. Outi Laamanen)
Old channel (photo. Outi Laamanen)
New nature-like bypass channel (photo. Outi Laamanen)
(photo. Outi Laamanen)
(photo. Outi Laamanen)

Catchment and subcatchment


River basin district Skagerrak and Kattegat River basin
River basin Rolfsån River Basin


River name River Rolfsån
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, Dam removal at Grönkullen, River Rolfsån, 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


Name Ålgårda bypass channel
WFD water body codes
WFD (national) typology
WFD water body name River Rolfsån
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body No
National/international site designation
Local/regional site designations
Protected species present Yes
Invasive species present Yes
Species of interest Atlantic salmon (Salmo salar), freshwater pearl mussel (Margaritifera margaritifera), European eel (Anguilla anguilla). Invasive species present: The signal crayfish (Pasifastacus leniusculus)
Dominant hydrology Artificially regulated
Dominant substrate
River corridor land use
Average bankfull channel width category 10 - 50 m
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category 10 - 100 m³/s
Mean annual discharge (m3/s) 11,6
",6" is not declared as a valid unit of measurement for this property.
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)

Project background

Reach length directly affected (m) 100
100 m
0.1 km
10,000 cm
Project started
Works started
Works completed
Project completed
Total cost category 5000 - 10000 k€
Total cost (k€)
Benefit to cost ratio
Funding sources National Fund for compensation of hydropower production (Svenska naturskyddsföreningens Bra miljöval) and owner company of the power plant Triventus AB, Regional Environment Authority (Länsstyrelsen Västra Götaland)

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

Reasons for river restoration

Mitigation of a pressure
Hydromorphology Quantity & dynamics of flow
Biology Fish: Disturbance-sensitive species, Fish: Species composition, Invertebrates: Disturbance-sensitive species
Other reasons for the project


Structural measures
Bank/bed modifications Building nature-like bypass channel, Creation of fish passes
Floodplain / River corridor
Planform / Channel pattern
Non-structural measures
Management interventions
Social measures (incl. engagement)


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

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

Supplementary Information

Edit Supplementary Information