Case study:Malltraeth Marsh
Project overview
Status | Complete |
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Project web site | |
Themes | Habitat and biodiversity |
Country | Wales |
Main contact forename | Nick |
Main contact surname | Elbourne |
Main contact user ID | |
Contact organisation | River Restoration Centre |
Contact organisation web site | http://www.therrc.co.uk |
Partner organisations | |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
The channel was canalised, embanked, and virtually featureless carrying highland water from upstream across a flat lowland valley. Marsh either side is grazing land designated as SSSI.
Aims of the project:
• To restore the open water characteristics of remnant cut-off channels of the Cefni that were being to be lost through drying and reed/rush/sweet-grass invasion.
• Combined with local restoration of high water tables, these measures ensured that the wildlife interests which gave rise to its notification as an SSSI are maintained and enhanced.
Works carried out:
• excavation of drying relic meanders and other open water areas
• sluices on drains/ditches to raise water levels in summer
• sluices and/or bunds to raise winter water levels
• willow/scrub control and other vegetation management
• improved bank profiles to the many ditches that traverse the floodplain
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Edit the catchment and subcatchment details
(affects all case studies in this subcatchment)
Site
Name | Malltraeth Marsh |
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WFD water body codes | |
WFD (national) typology | |
WFD water body name | |
Pre-project morphology | Embanked, Straightened |
Reference morphology | Wetland marsh |
Desired post project morphology | |
Heavily modified water body | No |
National/international site designation | UK - Site of Special Scientific Interest |
Local/regional site designations | Special Area of Conservation |
Protected species present | No |
Invasive species present | No |
Species of interest | |
Dominant hydrology | |
Dominant substrate | |
River corridor land use | Wetland, Rough unimproved grassland/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) | 70007,000 m <br />7 km <br />700,000 cm <br /> |
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Project started | 1993 |
Works started | |
Works completed | |
Project completed | 1996/01/01 |
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 |
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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
Mitigation of a pressure | Impoundments (not hydropower) |
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Hydromorphology | |
Biology | |
Physico-chemical | |
Other reasons for the project |
Measures
Structural measures
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Bank/bed modifications | |
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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Supplementary Information
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