Case study:Allt Lorgy River Restoration

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Location: 57° 16' 18.18" N, 3° 50' 33.26" W
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Project overview

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Status In progress
Project web site
Themes Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring
Country Scotland
Main contact forename Liz
Main contact surname Henderson
Main contact user ID
Contact organisation Spey Catchment Initiative
Contact organisation web site http://speyfisheryboard.com
Partner organisations Spey Fishery Board, Cairngorms National Park Authority, Scottish Natural Heritage, SEPA
Parent multi-site project
This is a parent project
encompassing the following
projects
No
Straightened section of the Allt Lorgy Burn

Project summary

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This project aims to restore the morphology and habitat of a 600m section of moderately high energy river and its floodplain by removing significant artificial constraints (man made embankments and boulders. Over the years these have canalised the water course from a multi braided to a single channel. By kick starting the process the intention is that over time the watercourse will do its own work to re-establish a natural equilibrium. In September 2012, five artificial embankments were lowered by the removal of over 900m3 of material. In stream boulders were removed and replaced with large wood structures. Additional wood structures were introduced in key locations and some of the extracted gravel was graded and stockpiled ready to be used for sediment reintoduction. Culvert pipes were removed from the floodplain and one large drainage ditch was in filled.

Monitoring surveys and results

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Lessons learnt

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Image gallery


Before - artificial embankment
After - lowered embankment
Before - Cross channel boulders
After - Wood Structure
Before - Upstream Left bank bar
After - Upstream left bank bar
Before - Large floodplain ditch
After - Floodplain ditch infilled
Downstream view post works
Downstream view during first flood event
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Catchment and subcatchment

Catchment

River basin district Scotland RBD
River basin River Spey

Subcatchment

River name River Avon
Area category 100 - 1000 km²
Area (km2) 545545 km² <br />54,500 ha <br />
Maximum altitude category 500 - 1000 m
Maximum altitude (m) 700700 m <br />0.7 km <br />70,000 cm <br />
Dominant geology granite, sedimentary, metamorphosed sedimentary
Ecoregion Great Britain
Dominant land cover Moorland, agriculture, forestry
Waterbody ID 23084



Other case studies in this subcatchment: River Avon Our Water Environment


Site

Name
WFD water body codes
WFD (national) typology
WFD water body name
Pre-project morphology
Reference morphology
Desired post project morphology
Heavily modified water body
National/international site designation
Local/regional site designations
Protected species present
Invasive species present
Species of interest
Dominant hydrology
Dominant substrate
River corridor land use
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) 600600 m <br />0.6 km <br />60,000 cm <br />
Project started 2012/03/01
Works started 2012/09/17
Works completed 2012/09/24
Project completed
Total cost category 10 - 50 k€
Total cost (k€)
Benefit to cost ratio
Funding sources CNPA, Scottish Environment Protection Agency

Cost for project phases

Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname
Investigation and design 1 - 10 k€ CBec Eco Engineering Dr H Moir
Stakeholder engagement and communication Less than 1 k€ Spey Catchment Initiative Liz Henderson
Works and works supervision 1 - 10 k€ Allan Munro Construction /Spey District Fishery Board
Post-project management and maintenance 1 - 10 k€ Spey Catchment Initiative Liz Henderson
Monitoring 1 - 10 k€ tbc



Reasons for river restoration

Mitigation of a pressure Flood risk management
Hydromorphology Channel pattern/planform
Biology
Physico-chemical
Other reasons for the project


Measures

Structural measures
Bank/bed modifications Removal of in stream boulders and replacement with wood structures, Additional strategic wood structures introduced, Graded extracted gravel to be used for sediment reintroduction, Embankment lowering
Floodplain / River corridor Removal of 3 culvert pipes. Infilling of a large drainage ditch.
Planform / Channel pattern
Other Site fenced to enable natural regeneration to take place. Supplementary planting planned for Spring 2013. Long term site monitoring programmed planned.
Non-structural measures
Management interventions
Social measures (incl. engagement)
Other Demonstration site for natural flood management techniques


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
http://youtu.be/-ugGQaLjz9g Allt Lorgy UK River Prize video

Supplementary Information

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