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Fish Rescue and Relocation Project in the River Rheidol

APEM Group - Case Study

Statkraft, Europe’s largest generator of renewable energy, called upon APEM Group’s specialist team for a technically challenging fish rescue from a subterranean fish pass, downstream of the hydropower scheme at Rheidol Reservoir, near Aberystwyth in Ceredigion, Wales.

Project Context

APEM were appointed by Statkraft to capture and relocate fish prior to essential maintenance work on the reservoir’s fish pass. The pass encompasses a series of chambers that are situated at regular intervals to ensure that the fish have places to rest as they pass through the structure. Over time these chambers can become inundated with debris and thus require maintenance to ensure they function correctly.

To support the essential maintenance works, APEM’s fish experts were deployed to relocate any fish before the culverts were drained and cleared.

Rheidol Fish rescue

Project Summary:

Location: Wales, UK.

Site area: 80m culvert

APEM Group Services: Environmental Assessment, Monitoring and Improvement

Species Found: European eels, Atlantic salmon, brown trout, perch, minnow

Rheidol Fish rescue

Project Challenges

Confined spaces and site terrain

A key challenge of this project was that most of the work was conducted below ground level in a controlled space. The APEM Group team had to be accredited to work in confined spaces to carry out the work safely.

Environmental Permits

APEM Group worked with Natural Resources Wales to obtain and implement the required Environmental Permits, within a tight timeframe, which ensured the mandated works had minimal impact on the rest of the local wildlife.

Electric Fishing

The method of catchment for efficient species relocation was electric fishing. This required specialist expertise from APEM Group’s team to catch all the fish safely in the enclosed spaces.

The APEM Group Solution

The APEM Group specialist team worked methodically through the culvert, targeting holding chambers within the fish pass, capturing fish from a range of species, including brown trout, perch, minnows and European eels (which are now considered to critically endangered and protected by UK law).

Once captured, all the fish were carefully craned to the surface before being relocated to suitable habitats downstream of the reservoir.


Fish were re-introduced back into the waters around our hydropower plant back in 1967, and the river remains a popular spot for anglers to this day. As a working power station, providing clean energy to Welsh homes, Statkraft’s Rheidol Hydropower plant requires regular maintenance, including on the innovative ‘fish lift’ that allows the salmon and trout to reach their old spawning grounds. This has now been completed to a high standard, ensuring fish can continue to pass upstream and downstream, as they have for almost 60 years.

Paul Pearson, Statkraft Mechanical Technician


Commercial and Environmental Impact

Due to strong and long-standing relationships with UK environmental regulators, the APEM Group team secured the appropriate permits and implemented a biosecurity plan for project deployment.

The work was completed safely and efficiently, to a very high standard, ultimately protecting the common and rarer species encountered, as well as ensuring the subsequent maintenance completed by Statkraft continued on schedule.

Contact Us

APEM Group are a world-class environmental consultancy with a global team of passionate scientist and technical experts. Specialists in providing high class solutions that have a positive environmental and societal impact, the APEM Group house a wide breadth and depth of core product and service-based competencies across Air, Land and Sea.

Have a project in mind? Contact us today.

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