Case study:Dumbreck Marsh & Garrel Burn Restoration

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Location: 55° 58' 24.21" N, 4° 4' 16.63" W
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Project overview

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Status Complete
Project web site
Themes Environmental flows and water resources, Fisheries, Habitat and biodiversity, Hydromorphology, Social benefits, Urban
Country Scotland
Main contact forename Francis
Main contact surname Hayes
Main contact user ID User:Francis Hayes
Contact organisation SEPA
Contact organisation web site http://www.sepa.org.uk/
Partner organisations North Lanarkshire Council, SEPA, Scottish Government, Clyde River Foundation
Parent multi-site project
This is a parent project
encompassing the following
projects
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Project summary

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Dumbreck Marsh is a ‘brownfield’ wetland area which developed naturally on post-industrial land in the mid/late 20th Century. The area was once heavily used for colliery activities and mineral railways. After the decline of the colliery industries the land was left fallow and gradually accommodated wetland habitats and associated species – eventually including the endangered lapwing? – it also became a valued area for greenspace, public access, and wildlife for the local Kilsyth community and was designated as a Local Nature Reserve by North Lanarkshire Council in…19…. Recently the marsh has suffered drying out and loss of wildlife, with access routes becoming eroded and therefore limiting public access. Historical mapping shows the Garrel Burn was straightened into an entrenched channel over 250 years during either 17th or 18th century creating simplified channel lacking in morphological diversity and subsequently habitat complexity while also disconnecting it from its floodplain at Dumbreck. Continually dredging of the channel and embankment construction resulted in greater levels of incision and floodplain disconnection. Further to this, two weirs located within the river at Kilsyth prevented access to over 1.5 km of quality upstream habitat to migrating fish (eel, trout, salmon, lamprey).. By restoring around 600m of the burn to a more natural lowland meandering planform, with a wider and shallower channel displaying gravel bars and pool features, the river will be able to accommodate a greater variety of wildlife and provide more attractive fish habitat. The channel also now allows the Garrel Burn to naturally flood into the wetland zone to help recharge the marsh with water. Two weirs have had “pre-weir” fish ladders built below them to allow migrating fish to, once again, reach the upstream habitat available to them in Kilsyth. Public access has been substantially improved with new pathways and resurfacing of existing popular routes. Three new attractive footbridges also enhance the experience of the riverside for the public. The paths at Dumbreck contain a variety of options for public enjoyment including short circular walks, and connectivity with other networks including the John Muir Way. Further community and visitor engagement and improved interpretation of the sites industrial and natural heritage is an ongoing part of the strategy for the Council. The Dumbreck Marsh where enhancements have taken place covers an area of around 70 hectares. The length of Garrel Burn enhanced by the work is 1 km. Around 600 m of a new meandering channel has been created through Dumbreck Marsh. The whole length of the river (1km) has had INNS (Japanese knotweed and Himalayan Balsam) eradicated, with existing banks re-profiled and seeded. Fish (salmon, trout, eel and lamprey) have access to the improved river (1km), and also with new fish ladders built on the two weirs at the upstream end of the works, fish now have access to 1.5km of river habitat within Kilsyth. Over 2km of footpaths have been restore, along with 3 new footbridges and a board walk for public access. Habitat enhancements – scrapes, bird boxes, sand martin wall, woody structures placed in channel for habitat and channel form. Disabled car parking improved. Further tree planting planned with community volunteers in 2022. Ongoing engagement with local communities will be led by North Lanarkshire Council for greenspace access and local heritage.

Monitoring surveys and results

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Work completed in April 2022. To date the Clyde River Foundation undertook monitoring before and during works and have found all key fish species in the area - lamprey, trout, eel and salmon. We hope to see these species thriving in future years.

Lessons learnt

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Complex "post industrial" zones, despite appearing to be greenspace can be complex locations to undertake engineering due to subsurface utilities, contaminants and historic refuse material. However by careful design and management natural river form and function can be achieved providing more resilience for the river and its wildlife.


Image gallery


Fish pass (lower)
Upper fish pass
Garrel Burn channel before work
New Meanders 2021
New Meanders 2021
Before During and After
Before & After
Upper fish pass During Works.jpg
Gravel meander During Works.jpg
ShowHideAdditionalImage.png


Catchment and subcatchment



Site

Name
WFD water body codes
WFD (national) typology
WFD water body name Garrel Burn
Pre-project morphology Canalised
Reference morphology lowland meandering channel
Desired post project morphology lowland meandering channel
Heavily modified water body Yes
National/international site designation
Local/regional site designations Local Nature Reserve
Protected species present Yes
Invasive species present Yes
Species of interest Atlnatic salmon, European Eel, Lamprey, Sea trout
Dominant hydrology
Dominant substrate gravel
River corridor land use post industrial marsh
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 2016/04/01
Works started 2020/04/01
Works completed 2022/04/14
Project completed
Total cost category 1000 - 5000 k€
Total cost (k€)
Benefit to cost ratio
Funding sources North Lanarkshire Council, Scottish Government, SEPA Water Environment Fund

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design 100 - 500 k€ WSP/CBEC
Stakeholder engagement and communication North Lanarkshire Council
Works and works supervision 1000 - 5000 k€ George Leslie/WSP/CBEC
Post-project management and maintenance
Monitoring



Reasons for river restoration

Mitigation of a pressure Canalisation and Embankment
Hydromorphology Straightening, embanking, dredging
Biology Fish ecology, INNS, wetland ecology
Physico-chemical
Other reasons for the project Public wellbeing and access to nature


Measures

Structural measures
Bank/bed modifications re-meandering, lowland shallow channel form, pool/riffle sequences
Floodplain / River corridor Floodplain reconnection with Dumbreck Marsh LNR
Planform / Channel pattern Re-meandering
Other
Non-structural measures
Management interventions
Social measures (incl. engagement) Community council, rotary club, access forum engagement, plus education days with local school children via Clyde River Foundation
Other More to follow once site has "bedded in" and greened up


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

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

Supplementary Information

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