Case study:Pearls in Peril LIFE+ GB Project - River South Esk

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Location: 56° 52' 0", -3° 10' 24"
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Project overview

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Status Complete
Project web site
Themes Fisheries, Habitat and biodiversity, Hydromorphology, Water quality
Country Scotland
Main contact forename Jackie
Main contact surname Webley
Main contact user ID User:Pearlsinperil
Contact organisation Scottish Natural Heritage
Contact organisation web site http://
Partner organisations
Parent multi-site project

Case_study:Pearls in Peril LIFE project

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Project summary

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The River South Esk is designated as a Special Area of Conservation with internationally important populations of freshwater pearl mussel and Atlantic salmon. It is presently assessed as being in ‘unfavourable’ condition by Scottish Natural Heritage (SNH). ‘Pearls in Peril’ is a UK-wide project to safeguard the future of the freshwater pearl mussel. The project undertook to restore sections of the River South Esk and an important tributary the 'White Water'. A study was commissioned to assess the impact of identified bank protection works on natural river processes and habitats important to the freshwater pearl mussel, prioritise sites for restoration and provide restoration designs.

A total of 21 bank protection sites in the upper river have previously been identified as impacting natural river processes since their construction during the 1990s. These are similar in appearance and purpose, comprising of large rock armour located on meander bends. They are present along three reaches of the upper River South Esk catchment, with nine at Moulzie in upper Glen Clova, eight at Acharn on the White Water upstream the confluence with the River South Esk, and four at Braedownie downstream of Acharn. There are no recorded populations of freshwater pearl mussel in these three river reaches, however downstream populations are influenced by the supply of suitable sediment from these reaches and by the health of the salmonid population.

Following stakeholder engagement,achieving all relevant licences and implementing necessary environmental protection measures; PIP removed 13 sections of rock armour river bank protection followed by bank reprofiling at Moulzie, Acharn and Braedownie as well as the re-connection of three paleochannels - one at Moulzie and two at Acharn on the main stem River South Esk and its tributary the White Water extending to 873m of in-stream river restoration work.

Monitoring surveys and results

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The work was completed in August 2015. Monitoring work is now underway and being implemented by the Esk District Salmon Fishery Board. Following large floods in December 2015 initial observations are showing a wider channel, improved composition of river substrates, availability of new salmonid spawning habitat, channel has become more sinuous.

Lessons learnt

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The timescales involved from conception to completion were longer than anticipated. The site presents a range of environmental sensitivities and land uses that required further consideration as part of the planning and physical works processes.

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Catchment and subcatchment


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Project background

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Reasons for river restoration

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Monitoring documents

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Supplementary Information

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