Over the past few months, the Canal and River Trust says good progress has been made with restoration of Toddbrook Reservoir, near Whaley Bridge in England. A major project to repair the reservoir swung into action after the dam auxiliary spillway was damaged during a period of intense rainfall in August 2019. Work to create a new reservoir overflow spillway is now in a final phase of intense activity over the next nine months.
With the challenging excavations and successful installation of foundations and piling complete, contractor Kier is now said to be well on course to build the new side weir, tumble bay and spillway with hundreds of tons of reinforced concrete.
On the site of the old playground, foundations are being laid to construct a new bridge over the channel just before it enters the River Goyt. And the stilling basin staircase and two large turrets, whose job is to slow down the water flow, are now clearly visible and nearly finished. Ultimately, they will be partially buried as part of the final landscaping works.
Later this spring, when the overflow spillway structure is sufficiently advanced, the work will be inspected by a government-approved specialist reservoir engineer before a new opening in the dam is made to enable completion of the spillway structure. The damaged concrete panelling will then be removed, the dam slope repaired over the summer and completely grassed over.
Re-filling of the reservoir will be allowed to take place naturally over the winter 2025/spring 2026, after the dam spillway and weir construction project is completed. Safety is paramount, the Canal and River Trust says, and the gradual rise in water level will be a phased 16-week monitored process. The effectiveness of the reservoir will be thoroughly tested to ensure the integrity of the new structure, as levels are held at eight different heights during the re-filling process.
The speed at which it re-fills will be influenced by the prevailing weather conditions in early 2026, but the trust is hopeful by the summer, the reservoir will be fully restored as a community resource for sailing, angling and swimming.
Scottish plans
SSE has unveiled plans to repower Lochay hydropower station in Perthshire, Scotland, with modern and efficient turbine technology.
Refurbishment of the existing 45MW hydroelectric power station, which was commissioned in 1958, is expected to breathe at least another 40 years of operational life into the scheme, ensuring it continues to play a vital role in the UK and Scotland’s renewable energy system for decades to come. Located in Killin, Lochay currently delivers around 170GWh of renewable generation each year.
The refurbishment works will see all main generation components being replaced with modern, efficient technology which will result in improved hydro power generation output without the need for any increased water volumes. All existing building and civil infrastructure from the1950s construction will be retained.
Main construction works began in April 2025, with delivery of the three-year programme expected to support up to 80 construction roles at its peak.
Robert Bryce, Director of Hydro, SSE Renewables said this announcement “further cements hydro’s vital role in the path to achieving UK and Scottish net zero carbon emissions targets”.
“As with many of our hydro stations,” he added, “Lochay has been a key part of the energy landscape for generations and this latest chapter will ensure it remains so for decades to come.”
- Voith Hydro – appointed as lead mechanical and electrical (M&E) contractor. Voith previously supported SSE Renewables in turbine and generator refurbishment projects at Deanie and Grudie Bridge power stations in Scotland and was also the main M&E contractor for the recently completed Tummel replant project (see below).
- Global Infrastructure – an Inverness-headquartered civil engineering and construction contractor appointed to undertake enabling works including site establishment and general site readiness, and expected to support a host of local and UK-based subcontractors.
- AJT Engineering Ltd – based in Aberdeen and appointed to design, procure and install the automatic self-closing valve protecting the steel penstock supplying the station, as well as assessment and recoating the internals of the penstock supported by specialist painting contractor Jack Tighe.
- Stantec – with bases in Edinburgh and Glasgow, is leading on civil design aspects and has been supporting SSE Renewables on the refurbishment project through its development.
- Konecranes Demag UK – based in East Kilbride and awarded the contract to modernise and upgrade the 70-year-old, 60 tonne station crane.
- McDonald Scaffolding – from Invergordon and appointed as scaffolding contractor.
SSE also recently completed a £50 million refurbishment of Perthshire’s iconic Tummel Bridge Power Station, increasing its potential generation from 34 to 40MW during optimum conditions. Such investment was one of the company’s largest ever for its hydro fleet, and involved replacement of the station’s two original Camel Back twin-runner, horizontal Francis turbines with new modern runner technology, extending the hydro power plant’s working life by at least 40 years.
Commissioned in 1933, Tummel Bridge Power Station is one of the oldest hydro power plants in Scotland and is at the centre of the overall Tummel Valley Hydro Scheme Cascade.
Housed within an iconic Category A listed structure, it currently delivers around 140GWh each year and plays an important strategic role in efficiently moving water onwards to the Clunie and Pitlochry power stations.
“Refurbishment schemes like Tummel Bridge are an integral piece of our low carbon future. Retrofitting existing energy assets with modern, highly efficient equipment, rather than rebuilding them, brings added value for our clients as well as the communities they serve,” said Craig Scott, Director of Hydropower at Stantec.
Other Scottish based supply chains firms involved in project delivery here included Global Energy Group which was responsible for forebay stoplog fabrication and tailrace gate modifications, while Rosyth-based KAEFER oversaw corrosion protection works on the penstocks and water intake structures.
Australian dam project
In Australia, AECOM has been appointment as the dams engineering services provider for Seqwater’s Dam Improvement Programme in Queensland, and will include the next tranche of upgrades on Wivenhoe, Somerset and North Pine Dams.
Enabling works are expected to commence on-site at Somerset Dam this year as part of the first stage of its upgrade. Staged strengthening works are also expected to commence at North Pine Dam to deliver enhanced safety benefits ahead of the major upgrade, and geotechnical investigations at Wivenhoe Dam concluded in late 2024.
The Lake Macdonald Dam Improvement Project is also part of Seqwater’s Dam Improvement Programme and will enhance water security, enabling the dam to withstand future extreme weather events.
Works including aquatic fauna surveys and the construction of haul roads and office buildings commenced in November 2024 to prepare the site for major construction activities this year. Ongoing gradual lake lowering has also been occurring since late 2024 ahead of the wet season and upcoming works. It also involves building a temporary upstream cofferdam to facilitate the safe construction of a new spillway, plus reconstruction of the existing earth embankments to ensure the dam meets modern regulatory requirements and continues to operate safely. The upstream cofferdam will keep the lake water level as high as possible throughout construction to ensure that ongoing environment, recreation and community amenity is maintained.
Australian bulk water supplier Seqwater owns and operates 26 dams that provide water security and flood mitigation for the Southeast Queensland region. Seqwater CEO, Emma Thomas, said while dams in the region were built to high safety standards of the time and remain safe, dam design and engineering has evolved significantly since.
“Through Seqwater’s Dam Improvement Programme, we’re investing in the longevity of our region’s dams to ensure they meet updated regulatory requirements and provide water security and flood mitigation benefits for generations to come,” she said. “The Dam Improvement Programme is an enormous undertaking. These projects are extremely complex and require extensive planning and technical expertise to ensure these major investments deliver strategic outcomes vital to the livelihoods of Southeast Queenslanders.”
