Case study:Rehabilitation of the river Segeråga: Difference between revisions

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{{Case study status
{{Case study status}}
|Approval status=Draft
}}
{{Location
{{Location
|Location=66.7167015, 13.2745597
|Location=66.71876048455148, 13.2851743630509
}}
}}
{{Project overview
{{Project overview
|Status=In progress
|Status=In progress
|Themes=Fisheries, Habitat and biodiversity, Land use management - agriculture, Monitoring, Water quality
|Themes=Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Water quality
|Country=Norway
|Country=Norway
|Main contact forename=Kjetil
|Main contact forename=Kjetil
|Main contact surname=Hansen
|Main contact surname=Hansen
|Contact organisation=Municipality of Rødøy
|Contact organisation=Rødøy
|Contact organisation url=www.rodoy.kommune.no/
|Partner organisations=Norwegian Institute for Nature Research (NINA),
|Multi-site=No
|Multi-site=No
|Project summary=Project background
Segeråga is located in Rødøy and Meløy municipality in the northern part of Norway. The river has been exposed to significant man-made changes during the last 30 years. New cultivation problems in the upper part of the river, with drainage and ditching of large peatlands, have had a documentable and significant negative ecological consequence for the river. The river has had increased sludge of fine particulate inorganic material (sludge/fine sand). The fish stock have probably been significantly reduces because of this.
The primary goal for the project is to increase the stocks of anadromous salmonids in Segeråga compared to the period 2013-2019.
A secondary goal is that the content of erosion and organic material in the water is reduced compared to the pre-situation, and that the river's quality as a habitat for fish and freshwater organisms is improved, especially through a reduction in the sludge of functional areas for trout and salmon.
Implementation
The project started with surveys in 2014, 2015 and 2016. Two reports describes the aquatic ecological status of segeråga, through benthic and juvenile fish surveys in the watercourse, supplemented with some water chemistry.
Based on this knowledge from the surveys, as well as field inspections and problemmapping, a rehabilitationplan was made in 2017. The rehabilitationplan suggests rehabilitation measures to re-establish the river as a river with sea-migrating salmonids, with particular emphasis on recovering the sea trout stock. This project was also a pilot project for this type of smaller rivers with man-made changes and new cultivation problems.
The rehabilitation started in 2017 includes measures as removing the inorganic material (sludge/fine sand), digging out ponds, gravel for spawning grounds, fish ladder, reduce runoff from agricultural land, habitat improvement, sediment ponds and reinforcement of riverbanks.
Summary/conclusion
The project successfully implemented all planned measures, with some locale adjustments in the field, such as the placement of spawning gravel. There has been no conflict with the landowners, and some have been involved in the measures. The project has been possible due to a committed municipality and funding from the state.
The last measures were implemented in 2020. Therefore, the results of the measures are not yet available. It will be important to monitor the river in a few years, to see the result from the measures and evaluate the project.
|Project title=Rehabilitation of the river Segeråga
}}
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{{Image gallery}}
{{Image gallery}}
{{Case study image
|File name=Removing inorganic material.JPG
|Caption=Removing inorganic material (sludge/fine sand. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=After measures in the lower part of river.JPG
|Caption=After removal of the inorganic material (sludge/fine sand), reinfoorcement of river bank and gravel for spawning grounds. Photo: Kristin B. Klausen, local watercoordinator.
}}
{{Case study image
|File name=Excavation of sediment ponds.JPG
|Caption=Excavation of sediment ponds in the upper part of the river. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=Sediment pond after measure.JPG
|Caption=Sediment pond. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=Excavation of sediment pond in the middel part.JPG
|Caption=Excavation of sediment ponds in the middle part of the river. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=Sediment pond in the middle part after measure.jpg
|Caption=Sediment ponds in the middle part of the river after measure. Photo: Kristin B. Klausen, local watercoordinator.
}}
{{Case study image
|File name=Construction of fishing ladder.jpg
|Caption=Construction of fishing ladder. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=Fish ladder after measure.JPG
|Caption=Fish ladder after measure. Photo: Kristin B. Klausen, local watercoordinator.
}}
{{Case study image
|File name=Digging of ditches and reinforcement of ditches.JPG
|Caption=Digging of ditches and reinforcement of ditches. Photo: Kjetil Hansen, Rødøy municipality
}}
{{Case study image
|File name=After digging of ditches and reinforcement of ditches.jpg
|Caption=After digging of ditches and reinforcement of ditches. Photo: Kristin B. Klausen, local watercoordinator.
}}
{{Case study image
|File name=Gravel for spawning grounds.jpg
|Caption=Gravel for spawning grounds. Photo: Kristin B. Klausen, local watercoordinator.
}}
{{Image gallery end}}
{{Image gallery end}}
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{{Case study subcatchment}}
{{Case study subcatchment}}
{{Site
{{Site}}
|Name=Segeråga
{{Project background}}
|WFD water body code=159-194-R
{{Motivations}}
|WFD (national) typology=RMM1221
{{Measures}}
|WFD water body name=Segeråga
|Pre-project morphology=shallower, overgrown
|Desired post project morphology=Run-glide, Ponded, Pool-riffle,
|Heavily modified water body=No
|Protected species present=No
|Invasive species present=No
|Species=Atlantic salmon (Salmo salar), Sea trout (Salmo trutta), arctic charr (Salvelinus alpinus),
|Dominant hydrology=Perennial Snow-rain (SR)
|Dominant substrate=Silt
|River corridor land use=Intensive agriculture (arable), Coniferous woodland (semi natural),
}}
{{Project background
|Reach length directly affected=10000
|Total cost category=100 - 500 k€
|Total1 cost=206
|Funding sources=Norwegian Environment Agency, County Governor og Nordland
|Investigation and design cost category=10 - 50 k€
|Invst and design cost=36
|Investigation and design Lead organisation=Rødøy municipality
|Works1 and supervision cost category=100 - 500 k€
|Wrk and supervision cost=170
|Works and supervision Lead organisation=Rødøy municipality
}}
{{Motivations
|Specific mitigation=Land drainage,
|Hydromorphological quality elements=Channel pattern/planform, Continuity of sediment transport, Flow velocities, Structure & condition of riparian/lake shore zones, Substrate conditions, Width & depth variation,
|Biological quality elements=Fish: Abundance, Fish: Age structure, Invertebrates: Diversity,
|Physico-chemical quality elements=Nutrient concentrations,
|Other motivation=Bank erosion,
}}
{{Measures
|Bank and bed modifications measure=Construction gravel bays, gravel for spawning grounds, Removal of sediment, Removal of fish barriers, Natural erosion embankments, er
|Floodplain / River corridor=Removal of sediments,
|Planform / Channel pattern=Decrease sedimentation, Creation of pond,
|Other technical measure=Fish habitat restoration, Improving fish migration, sediment ponds
|Management interventions=Reducing bank side collapse (source of sediment),
}}
{{Hydromorphological quality elements header}}
{{Hydromorphological quality elements header}}
{{Hydromorphological quality element table row
{{Hydromorphological quality element table row

Latest revision as of 13:30, 17 February 2021

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Location: 66° 43' 7.54" N, 13° 17' 6.63" E
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Project overview

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Status In progress
Project web site
Themes Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Hydromorphology, Water quality
Country Norway
Main contact forename Kjetil
Main contact surname Hansen
Main contact user ID
Contact organisation Rødøy
Contact organisation web site
Partner organisations Norwegian Institute for Nature Research (NINA)
Parent multi-site project
This is a parent project
encompassing the following
projects
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Project summary

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Monitoring surveys and results

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Lessons learnt

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Image gallery


Removing inorganic material (sludge/fine sand. Photo: Kjetil Hansen, Rødøy municipality
After removal of the inorganic material (sludge/fine sand), reinfoorcement of river bank and gravel for spawning grounds. Photo: Kristin B. Klausen, local watercoordinator.
Excavation of sediment ponds in the upper part of the river. Photo: Kjetil Hansen, Rødøy municipality
Sediment pond. Photo: Kjetil Hansen, Rødøy municipality
Excavation of sediment ponds in the middle part of the river. Photo: Kjetil Hansen, Rødøy municipality
Sediment ponds in the middle part of the river after measure. Photo: Kristin B. Klausen, local watercoordinator.
Construction of fishing ladder. Photo: Kjetil Hansen, Rødøy municipality
Fish ladder after measure. Photo: Kristin B. Klausen, local watercoordinator.
Digging of ditches and reinforcement of ditches. Photo: Kjetil Hansen, Rødøy municipality
After digging of ditches and reinforcement of ditches. Photo: Kristin B. Klausen, local watercoordinator.
Gravel for spawning grounds. Photo: Kristin B. Klausen, local watercoordinator.
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Catchment and subcatchment



Site

Name
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body
National/international site designation
Local/regional site designations
Protected species present
Invasive species present
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
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)
Average channel gradient category
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m)
Project started
Works started
Works completed
Project completed
Total cost category
Total cost (k€)
Benefit to cost ratio
Funding sources

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
Hydromorphology
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications
Floodplain / River corridor
Planform / Channel pattern
Other
Non-structural measures
Management interventions
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
Substrate conditions Yes No Yes No No Awaiting results
Width & depth variation Yes No Yes No No Awaiting results

Biological quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Fish: Abundance Yes No No Yes No Awaiting results
Fish: Age structure Yes No No Yes No Awaiting results
Invertebrates: Diversity Yes No No Yes No Awaiting results
Invertebrates: Abundance Yes No No Yes No Awaiting results

Physico-chemical quality elements

Element When monitored Type of monitoring Control site used Result
Before measures After measures Qualitative Quantitative
Nutrient concentrations Yes No No Yes No Awaiting results
PH Yes No No Yes No Awaiting results

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://https://brage.nina.no/nina-xmlui/handle/11250/2446580 Plan for rehabilitation of the river
http://https://brage.nina.no/nina-xmlui/handle/11250/2436896 Fish biological survey
http://https://niva.brage.unit.no/niva-xmlui/handle/11250/2478427 Survey of physico-chemical quality elements and biology

Supplementary Information

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