Case study:Restoration of the River Korvajoki
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- 1 Project overview
- 2 Image gallery
- 3 Catchment and subcatchment
- 4 Site
- 5 Project background
- 6 Reasons for river restoration
- 7 Measures
- 8 Monitoring
- 9 Additional documents and videos
- 10 Additional links and references
- 11 Supplementary Information
|Project web site|
|Themes||Fisheries, Habitat and biodiversity, Hydromorphology|
|Main contact forename||Jarmo|
|Main contact surname||Huhtala|
|Main contact user ID||User:Kasvio|
|Contact organisation||Centre for Economic Development, Transport and the Environment for Lapland|
|Contact organisation web site|
|Parent multi-site project|
| This is a parent project
encompassing the following
The River Korvajoki is 2 900 meters long and it flows though forest areas from the Lake Korvajärvi to the Lake Simojärvi. The river bed is mainly sand and contains rocks and gravel. The water quality in the river is good or very good.
The Centre for Economic Development, Transport and the Environment for Lapland restored three sections in the river. The restoration was made to improve the living conditions of the fish and other species. Rocks and gravel was placed to the river to make rapid areas more suitable for the trouts to reproduce. The aim of the retoration was to improve the living conditions of migratory fish and to make the river more nature-like and closer to its natural state. Trouts, grayling and macro invertebrates will benefit from the restoration and not only in the river but also in the nearby lakes. The rivers in the area are straightened for log floating since 1900 century. Also the natural state in the rivers are altered because of intense forestry and bog drainage.
The restoration plan was accepted 4.3.2011 and the work started immediately. The plan was restore six rivers in the area. The area is highly appreciated among the fly fishers and its very popular recreational area.
The restoration plan aimed to slow down the current and produce suitable nesting habitats for the trouts and shelter places for the juveniles. Also versatility to the river bed was improved by digging few wider areas. Gravel was brought and placed to the river in several places bed to ensure the nesting habitats for the migratory fish. Before the restoration many stones were taken away from from the river and places a side of the river. All the stones that were piled up next to the river were used in the restoration work. Tree junks and other wooden material was used to make the flow more versatile and give more sheltered areas for juveline fish and living habitats and food for macro inveretbrates.
The lenght of the first restored area is 1 170 meters and the width is 2,5 in average the area in total was 3 000 m2. The second was not restored in anyhw beacuse there are several extremely vulnerable pearl mussels (Margaritifera margaritifera). The thirds section was 600 meters, width 3 meters and the area was 2 000 m2. The flow in that sections was slow so the gravel, rocks and wooden particles were placed in the channel to make the flow curve more.
Monitoring surveys and results
Catchment and subcatchment
Cost for project phases
Reasons for river restoration
Hydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Additional documents and videos