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

Revision as of 12:07, 19 February 2016 by Pearlsinperil (talk | contribs)

Jump to: navigation, search
This case study is pending approval by a RiverWiki administrator.
Approve case study


(0 votes)

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

Location: 54° 31' 51", -3° 26' 37"
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 In progress
Project web site http://
Themes Fisheries, Habitat and biodiversity, Hydromorphology, Water quality
Country England
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 West Cumbria Rivers Trust, Environment Agency, Lake District National Park, United Utilities
Parent multi-site project

Case_study:Pearls in Peril LIFE project

This is a parent project
encompassing the following
Project picture

Project summary

Edit project overview to modify the project summary.

The River Ehen, supports the largest viable population of pearl mussels left in England, estimated at between 350,000 and 500,000 individuals (Ian Killeen 2006). The Ehen is the most important river in England for freshwater pearl mussels, both biogeographically and for its size and population structure. 13km of the main River Ehen, from the outlet of Ennerdale Water, to the confluence of the River Keekle in Cleator Moor are designated as protected sites for both pearl mussels and Atlantic Salmon.

Pearls in Peril has delivered actions that work to reduce diffuse pollution, siltation and erosion and aim to improve water quality to safeguard the future of the River Ehen freshwater pearl mussel population.

The project has produced a river wide Conservation Management Plan that, for the first time, brought together stakeholders across the catchment to identify key issues and priorities. Directed by the Management Plan and supported by project partners the project has completed over 240m of willow spiling, fenced livestock from 5km of riverbank, provided alternative livestock waterings and planted over 7000 trees. Three riverbank sites have been restored with bank re-profiling, tree planting and fencing. In river obstructions causing erosion and scour have been removed and brash bundles have been used to encourage natural river bank restoration.

Volunteers have undertaken incredible amounts of work including hedge laying, making brash bundles and tree planting.

Monitoring surveys and results

Edit project overview to modify the Monitoring survey and results.

Monitoring work has been undertaken including sonde data collection, freshwater pearl mussel survey and electro-fishing. On the River Ehen Atlantic salmon are the preferred host fish for as part of the freshwater pearl mussel lifecycle.

Lessons learnt

Edit project overview to modify the lessons learnt.

Pearls in Peril is supported on the River Ehen by a Technical Steering Group. This Group brings together key stakeholders in the catchment and shares information on other activities and projects being undertaken. Through this group many opportunities have been realised and additional benefits gained. This approach is worth considering for future projects on rivers where there are many interested stakeholders.

Image gallery


Catchment and subcatchment


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)
Project started
Works started
Works completed
Project completed
Total cost category
Total cost (k€)
Benefit to cost ratio
Funding sources

Cost for project phases

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

Reasons for river restoration

Mitigation of a pressure
Other reasons for the project


Structural measures
Bank/bed modifications
Floodplain / River corridor
Planform / Channel pattern
Non-structural measures
Management interventions
Social measures (incl. engagement)


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

Edit Supplementary Information