Case study:Water of Dye Fish Pass Project
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Project overview
Status | Complete |
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Project web site | |
Themes | Fisheries |
Country | Scotland |
Main contact forename | Nick |
Main contact surname | Elbourne |
Main contact user ID | User:NickRRC |
Contact organisation | River Restoration Centre |
Contact organisation web site | |
Partner organisations | River Dee Trust |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
The Water of Dye is a tributary of the Water of Feugh - itself a tributary of the River Dee. 15km along the 26km length of the Dye are two weirs - the upper acting as a partial impoundment to supply a nearby drinking water storage reservoir and the lower Crump weir acting as a flow accelerator for flow monitoring purposes.
Fisheries surveys conducted between 1997 and 2006 showed that the weirs were acting as significant barriers to upstream Atlantic salmon migration - cutting off 11km of good spawning and nursery habitat.
In 2008, two fish passes were installed on the two weirs. This initially involved constructing pre-weirs below the pre-existing weir structures, in order to raise tailwater levels to ease fish passage. In addition, the upper weir also had a 'step-pool' pass installed, as the weir was deemed to be particularly steep for fish passage. This allowed to fish to climb the weir in two 'jumps'.
In order to determine the ecological success of the project, the River Dee Trust conducted pre/post-restoration electro-fishing surveys, to track any changes in fish abundance above and below the weirs. These surveys determined the following:
- Statistically significant increase in salmon parr above the weir in 2010 and 2011, compared with pre-restoration baseline.
- In 2011, salmon parr numbers u/s of weir were found to be not statistically different to abundances d/s for the first time - indicating that the fish pass had been successful in promoting free u/s passage for spawning.
- Decline in trout fry and parr above weir following fish pass installation, however the control site d/s showed no significant decline. Possibly due to outcompetition for habitat and territory by salmon, which are naturally far more suited to the habitat. A similar issue was seen following fish pass installation on the Tweed.
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 | North East Scotland |
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River basin | Dee |
Subcatchment
River name | Water of Dye |
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Area category | 10 - 100 km² |
Area (km2) | |
Maximum altitude category | 500 - 1000 m |
Maximum altitude (m) | 778778 m <br />0.778 km <br />77,800 cm <br /> |
Dominant geology | Siliceous |
Ecoregion | Great Britain |
Dominant land cover | Upland Moorland/Grassland |
Waterbody ID |
Site
Name | Water of Dye |
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WFD water body codes | 23329 |
WFD (national) typology | Small, Mid, Organic |
WFD water body name | Water of Dye - upper catchment |
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 | No |
Invasive species present | No |
Species of interest | Salmon, brown/sea trout |
Dominant hydrology | |
Dominant substrate | Peat/Bedrock |
River corridor land use | Pasture |
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) | |
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Project started | 2008 |
Works started | |
Works completed | |
Project completed | |
Total cost category | |
Total cost (k€) | |
Benefit to cost ratio | |
Funding sources | Life-Nature Conservation of Atlantic Salmon in Scotland |
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 | River Dee Trust |
Reasons for river restoration
Mitigation of a pressure | |
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Hydromorphology | |
Biology | Upstream migratory fish passage for spawning. |
Physico-chemical | |
Other reasons for the project |
Measures
Structural measures
| |
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Bank/bed modifications | Installation of fish passes into two existing weirs. |
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 |
Biological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative | |||
Fish | Yes | Yes | No | Yes | Yes | Improvement |
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
Image gallery
Additional documents and videos
Additional links and references
Link | Description |
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http://www.riverdee.org.uk/FileLibrary/Content/Publications/2012%20Survey%20Bulletin Dye%20fish%20passes.pdf | River Dee Trust - 2012 Bulletin |
http://www.riverdee.org.uk/FileLibrary/Content/Publications/Dye%20fish%20passes%202011 %20survey%20bulletin.pdf | River Dee Trust - 2011 Bulletin |
Supplementary Information
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