Case study:Inchewan Burn Bed restoration

From RESTORE
Jump to: navigation, search
0.00
(0 votes)


To discuss or comment on this case study, please use the discussion page.


Location: 56° 33' 27", -3° 34' 45"
Edit location
Loading map...
Left click to look around in the map, and use the wheel of your mouse to zoom in and out.


Project overview

Edit project overview
Status Complete
Project web site
Themes Fisheries, Habitat and biodiversity, Hydromorphology
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 http://www.therrc.co.uk
Partner organisations
Parent multi-site project
This is a parent project
encompassing the following
projects
No
The restored Inchewan Burn

Project summary

Edit project overview to modify the project summary.


During the creation of a bypass by the river, the burn was engineered by encasing it in gabion baskets to provide structural protection for the roadway piers. Reno mattresses were also used to prevent down-cutting by the burn. In the high-energy environment of the burn, the reno mattresses' protective PVC layer was eroded and the galvanised coating of the mattresses exposed, causing them to split open and the withheld material released. The remaining wire became a hazard for fish, snaring many. Additionally, the downstream gabions would often block surface water in low-flow conditions, with water simply flowing 'through' them in the gaps in between. Accordingly, fish migration was often blocked.

The restoration saw the removal of the reno mattresses and the introduction of boulders to create pools, diversify flow and collect sediment. These boulders were set in concrete to prevent their movement in high flows. Timber extraction of non-native conifer plantation. Planting of native broadleaf tree species. Local school children helped to plant the native broadleaf tree species.

Monitoring surveys and results

This case study hasn’t got any Monitoring survey and results, you can add some by editing the project overview.

Lessons learnt

This case study hasn’t got any lessons learnt, you can add some by editing the project overview.


Image gallery


The restored burn
The degraded reno mattresses
Low flow in the old wire bed
ShowHideAdditionalImage.png


Catchment and subcatchment

Catchment

River basin district Tay
River basin Inchewan

Subcatchment

River name Inchewan Burn
Area category
Area (km2)
Maximum altitude category
Maximum altitude (m)
Dominant geology Siliceous
Ecoregion Great Britain
Dominant land cover Urban, Woodland
Waterbody ID



Site

Name Birnam
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology Single channel, Straight, Embanked, Revetments
Reference morphology Step-pool, Pool-riffle, Single channel
Desired post project morphology
Heavily modified water body Yes
National/international site designation
Local/regional site designations
Protected species present Yes
Invasive species present No
Species of interest atlantic salmon (Salmo salar)
Dominant hydrology Quick run-off
Dominant substrate Bedrock
River corridor land use Urban, Woodland
Average bankfull channel width category 5 - 10 m
Average bankfull channel width (m)
Average bankfull channel depth category 0.5 - 2 m
Average bankfull channel depth (m)
Mean discharge category 1 - 10 m³/s
Mean annual discharge (m3/s)
Average channel gradient category 0.01 - 0.1
Average channel gradient
Average unit stream power (W/m2)


Project background

Reach length directly affected (m) 100 m
0.1 km
10,000 cm
Project started 2007/09/01
Works started
Works completed 2007/11/01
Project completed
Total cost category 50 - 100 k€
Total cost (k€) 100 k€
100,000 €
Benefit to cost ratio
Funding sources Scottish Environment Protection Agency, Perth Council, Scottish Natural Heritage

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design Perth Council John Monteith
Stakeholder engagement and communication Perth Council John Monteith
Works and works supervision Perth Council
Post-project management and maintenance Perth Council
Monitoring Perth Council John Monteith



Reasons for river restoration

Mitigation of a pressure
Hydromorphology Quantity & dynamics of flow, continuity of sediment transport, Flow velocities
Biology Restore free passage for fish and promote fish spawning (ie. salmonids).
Physico-chemical
Other reasons for the project Landscape enhancement


Measures

Structural measures
Bank/bed modifications Removal of artificial wire/stone bed, Replicated upstream boulder bed step/pool sequence
Floodplain / River corridor Removal of non-native species, Large scale planting of native species
Planform / Channel pattern In-channel placement of boulders to provide flow diversity
Other
Non-structural measures
Management interventions
Social measures (incl. engagement) Student Education
Other Local support


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 No Yes Yes No No 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



Additional documents and videos


Additional links and references

Link Description
http://www.therrc.co.uk/rrc case studies1.php?csid=52 River Restoration Centre Case Study
http://www.therrc.co.uk/case studies/sepa article inchewan%20burn.pdf SEPA article
http://www.therrc.co.uk/2012%20Conference/Outputs/Gilvear%202%20Final.pdf Inchewan Burn Post Project Appraisal: David Gilvear's presentation from the RRC 2012 Conference

Supplementary Information

Edit Supplementary Information

RRC visit notes (2008):

The new bed has enabled free passage to the upper burn and has had a dramatic impact on the visual ‘eyesore’ previously viewed by users of the popular pathway. The construction of a step-pool bedrock and boulder bed has added stability to the channel and now allows a much freer movement of bed sediment.

The concept of needing to anchor the ‘key’ boulders into the engineered bed but burying this structural element under 500mm+ of placed material allowed concerns over structural stability, morphology and aesthetics to be integrated into a common solution.