Case study:Restorations of Ritobäcken brook
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Project overview
Status | Complete |
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Project web site | |
Themes | Habitat and biodiversity |
Country | Finland |
Main contact forename | Jukka |
Main contact surname | Jormola |
Main contact user ID | |
Contact organisation | SYKE |
Contact organisation web site | http://www.environment.fi |
Partner organisations | |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
Ritobäcken brook is a small tributary of River Sipoonjoki which is located near to Helsinki partly in a Sipoonkorpi National Park. Brook serves as a drainage channel for the surrounding agricultural fields which constitute 13% of the 10 km2 catchment area. The brook is also a reproduction area for the vulnerable sea run brown trout (Salmo trutta) of the Baltic Sea. Brook has been restored twice. First time was 2006 when 230 meters of dredged and straightened brook was restored as the aim of improving the habitat for the existing brown trout stock. The object was to support the natural development of the brook by adding sinousity and width and depth variation. Also stones and gravel were added and replaced to create habitats for the brown trout.
In 2010 brook was restored as the aim of maintaining and enhancing the habitat diversity of the brook for migratory fish while decreasing flooding of the fields. Because of the significant bank and bed erosion in the upstream reaches and reduced conveyance in the downstream reaches fields were inundated during high flows. The two-stage cross-section was constructed on excavating a floodplain on one side of the channel and leaving the opposite side and bottom intact to prevent the digging of the stream bed. The flood terrace has so far been large enough to prevent flooding to the arable areas. Spawning brown trout have been monitored downstream in autumn 2010 and 2011, showing that no harm for fish was done by the excavation. The increase of trout habitat to the excavated section upstream can also be expected, with help of further restoration.
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 | Southern Finland |
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River basin | Sipoonjoki River |
Subcatchment
River name | Ritobäcken brook |
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Area category | 10 - 100 km² |
Area (km2) | 12 km²1,200 ha <br /> |
Maximum altitude category | |
Maximum altitude (m) | |
Dominant geology | Organic (i.e. Peat) |
Ecoregion | Fenno-Scandian Shield |
Dominant land cover | Intensive agriculture |
Waterbody ID |
Other case studies in this subcatchment: Ritobäcken-environmentally preferable two-stage drainage channels
Site
Name | Cathment of Ritobäcken Brook |
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WFD water body codes | |
WFD (national) typology | |
WFD water body name | |
Pre-project morphology | Sinuous, Straightened |
Reference morphology | over-widened |
Desired post project morphology | |
Heavily modified water body | |
National/international site designation | EU - Special Area of Conservation |
Local/regional site designations | |
Protected species present | |
Invasive species present | |
Species of interest | |
Dominant hydrology | Ephemeral |
Dominant substrate | |
River corridor land use | Intensive agriculture (arable) |
Average bankfull channel width category | |
Average bankfull channel width (m) | |
Average bankfull channel depth category | 0.5 - 2 m |
Average bankfull channel depth (m) | |
Mean discharge category | |
Mean annual discharge (m3/s) | |
Average channel gradient category | |
Average channel gradient | 0.002 |
Average unit stream power (W/m2) |
Project background
Reach length directly affected (m) | |
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Project started | 2009/01/01 |
Works started | 2010/01/01 |
Works completed | 2010/01/01 |
Project completed | |
Total cost category | |
Total cost (k€) | |
Benefit to cost ratio | |
Funding sources | Ministry of Agriculture and Forestry; Ministry of Environment; Regional ELY-centre; and EU |
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
Measures
Structural measures
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Bank/bed modifications | Adding sinuosity, Introducing gravel, Re-introducing stones |
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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http://www.balticdeal.eu/Paljok Farm/Baltic Deal.mht | Information about restauration of the Ritobacken brook |
http://civil.aalto.fi/en/research/water/research/environmental hydraulics/sediment processes/ | Physical sediment processes in environmental channels |
http://www.restorerivers.eu/Portals/27/Ritob%C3%A4cken%20brook,%20Finland.pdf | Restoration of Ritobäcken brook |