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, Cairngorm 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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Catchment and subcatchment

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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

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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

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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	SEPA Restoration fund, CNPA

Cost for project phases

Reasons for river restoration

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Mitigation of a pressure	Removal of artificial constraints (embankments and boulders) to restore morphology and habitat of a multi braided watercourse that had been canalised into a single channel.
Hydromorphology
Biology
Physico-chemical
Other reasons for the project	Demonstrate and monitor natural flood management techniques in the catchment

Measures

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Structural measures
Bank/bed modifications	Removal of 900m3 of embankment material. Removal of in stream boulders and replacement with wood structures. Additional strategic wood structures introduced. Graded extracted gravel to be used for sediment reintroduction
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