Difference between revisions of "Case study:Nursery habitat for the freshwater pearl mussel in Haukåsvassdraget"

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{{Project overview
 
{{Project overview
 
|Status=Complete
 
|Status=Complete
|Themes=Habitat and biodiversity, Hydromorphology, Land use management - agriculture, Water quality, Urban
+
|Themes=Habitat and biodiversity, Hydromorphology, Land use management - agriculture, Monitoring, Social benefits, Spatial planning, Water quality, Urban
 
|Country=Norway
 
|Country=Norway
 
|Main contact forename=Håvard
 
|Main contact forename=Håvard

Latest revision as of 11:11, 4 December 2019

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Location: 60° 29' 40", 5° 22' 22"
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Project overview

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Status Complete
Project web site
Themes Habitat and biodiversity, Hydromorphology, Land use management - agriculture, Monitoring, Social benefits, Spatial planning, Water quality, Urban
Country Norway
Main contact forename Håvard
Main contact surname Bjordal
Main contact user ID
Contact organisation Bergen municipality
Contact organisation web site http://www.bergen.kommune.no
Partner organisations University of Bergen (UiB), Norwegian Environment Agency, Rådgivende Biologer AS, Entrepreneur Magne Løvaas AS
Parent multi-site project
This is a parent project
encompassing the following
projects
No
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Project summary

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The Haukås watercourse (Haukåsvassdraget) is located in the northern part of Bergen municipality. The catchment is just under 9 km2 and the length is about 6 km. There are large flood variations. The remnant population of the freshwater pearl mussel can be documented back to the 17th century by court records. Bergen municipality purchased a large wetland area, Haukåsmyrene in the early 1900s. Agriculture developed throughout the river area and resulted in the lowering of water levels, cultivation, canalization and drainage. Then came a period of strong urbanization and development. The mussels were thought to be extinct until 2002. Then a few hundred old mussels were found - a typical sign that the water conditions are too poor for recruitment. The water quality and possible measures were quickly identified by a close cooperation between public management and the academic community.

Comprehensive mapping of both diffuse and point source emissions where conducted and requests where sent in order to stop/reduce pollution. Two important challenges had to be solved to save the mussel population; a) the mussels had to be helped with recruitment, b) the river's water conditions had to be improved.

A nursery habitat for the freshwater pearl mussel was built in a side stream following a Czech concept. Based on experience, such nursery habitats create good growing conditions for both mussel and trout. When the mussels grow larger, they can release and settle in favorable locations in the main river. It should be mentioned that the Haukås marshes (Haukåsmyrane), which are central to the watercourse, have already been designated as a priority restoration area for wetlands.

There are continuous improvements in breeding and cultivation of freshwater pearl mussels. The pioneering work of the University of Bergen's facility at Austevoll is a success that provides hope for both the mussels in Haukås and other endangered populations. Batches of mussels were released back in the river with promising results. It is still too early to know for sure how the mussel habitat will work overtime. The biological and water chemistry developments are being monitored.

Unfortunately, there has been recorded episodes of pollution into the river that has led to mussel death the past years. For instance, in 2017 (Johnsen, G.H, S. Kålås & I. Wathne 2018. Status for elvemusling i Haukåsvassdraget 2017. Radgivende Biologer AS, rapport 2629, 34 sider, ISBN 978-82-8308-485-6.)

Monitoring surveys and results

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https://www.radgivende-biologer.no/wp-content/uploads/2019/06/2629.pdf

Lessons learnt

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The situation in the small urban Haukåsvassdraget is unclear. It will take time to achieve safe and stable good ecological conditions. Cultivation breeding of the freshwater pearl mussel is already a success. In order to succeed in returning mussels to the main river, water conditions must be improved. Facilitating nursery habitats could be a supplement in the conservation work. The mussel habitat at Haukås is an important trial project.


Image gallery


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Catchment and subcatchment



Site

Name Haukåsvassdraget
WFD water body codes 061-176-R
WFD (national) typology RWL1321
WFD water body name Haukåsvassdraget
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 No
Species of interest The freshwater pearl mussel
Dominant hydrology
Dominant substrate
River corridor land use Urban
Average bankfull channel width category
Average bankfull channel width (m)
Average bankfull channel depth category
Average bankfull channel depth (m)
Mean discharge category 0.1 - 1.0 m³/s
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 2014/01/01
Works started
Works completed
Project completed 2016/01/01
Total cost category
Total cost (k€) 129
129 k€
129,000 €
Benefit to cost ratio
Funding sources Norwegian Environment Agency, Bergen municipality, Fana stein og gjenvinning AS, Haukås jordsortering AS

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 Pollution incident, Urbanisation
Hydromorphology
Biology Invertebrates: Disturbance-sensitive species
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications
Floodplain / River corridor Creation of side channel, Habitat creation
Planform / Channel pattern
Other
Non-structural measures
Management interventions Ensuring biodiversity, Reduced pollution
Social measures (incl. engagement) Awareness raising, Environmental education activities with local schools
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
Invertebrates: Disturbance-sensitive species 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://uni.no/media/manual upload/LFI 296 4opplag.pdf Measures Handbook for better physical aquatic environment
http://www.radgivende-biologer.no/wp-content/uploads/2019/06/2629.pdf Report

Supplementary Information

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