Toddbrook Reservoir repairs reach major £15m milestone

During a media open day on Friday June, 23 the Canal and River Trust, which cares for Toddbrook Reservoir, announced the installation of nearly 1,000 sheet piles forming the route of the new £15 million overflow spillway channel had begun.

A new interactive fly-though 3D computer model showing how the finished structures will look is now available on the trust’s website and members of the public are invited to see progress up close at two public open days hosted on site on Friday 7 and Saturday 8 July.

Julie Sharman, chief operating officer with the Canal and River Trust, said: “We have reached a significant milestone with the project and it’s important to share the progress made on the construction work to restore the reservoir - particularly so everyone can now see the route of the new overflow spillway. It’s essential that we restore the reservoir both for the amenity value to the community in Whaley Bridge and also for its role in supplying water to the Peak Forest and Macclesfield canals.”

The existing auxiliary spillway on the dam wall was damaged in the summer of 2019 after excessive rainfall and there were fears the dam could collapse and the water could cascade down and flood the town of Whaley Bridge as well as the surrounding area.

Residents were told to leave their homes and a national emergency operation to save the dam was launched involving emergency services, partner agencies and volunteers and even saw former prime minister Boris Johnson visit the dam.

Since then the reservoir has been kept virtually empty.

Following two public consultations and a detailed planning application, work started on the chosen restoration scheme in autumn last year and is expected to take just over two years to complete. The northern end of the town’s Memorial Park has been temporarily closed to the public to make way for the site compound and spillway works.

Lynn Pegler, communications manager for the trust, said: “The project, designed by Arup and is being delivered by principal contractor Kier, involves removing the damaged auxiliary spillway and replacing it with a new overflow spillway structure to the north of the dam.

“This will feature a side channel weir, tumble bay, spillway channel and stilling basin, which will link into the existing bypass channel flowing into the River Goyt in the town’s Memorial Park.”Now the sheet piles are in place, the ground can be excavated to form the new channel, which will be lined in concrete, forming a base and side walls for the new spillway, says the trust.

These will be constructed over the coming months, starting with the weir and tumble bay at the top by the reservoir, followed by the spillway chute, stilling basin and two cylindrical concrete turrets, which are an essential engineering feature to slow the water flow before it enters the open channel and River Goyt.

A further 500 concrete piles will be installed at two locations – the top of the dam crest and tumble bay, and at the stilling basin.

The trust says this involves pouring concrete into cylindrical columns, which are then reinforced with steel to form the structure’s foundations. A couple of further short periods of sheet piling are also expected to take place from early August.

Julie said: “This month we are also celebrating the significant role female engineers are playing in delivering the Toddbrook construction project, not only from the Canal and River Trust but also from our contractors Kier and engineering designers Arup.

“Leading up to International Women in Engineering Day on 23 June, my colleagues have visited several local schools to hopefully inspire a new generation of female students to pursue careers in science and engineering.

“It is fantastic that we are leading by example on such a challenging and high-profile construction project.”

At the end of the main construction works, concrete panels from the 1970s auxiliary spillway will be removed and the dam will then be repaired and grassed over.

A new playground will be rebuilt in the Memorial Park, which will also be re-landscaped with trees, wildlife habitats, additional paths and a new footbridge over the bypass channel. The sailing club will be relocated behind the new tumble bay, where it will feature a new slipway, clubhouse, boat storage and car park.

The trust says temporary sheet piles will be kept in place at the dam crest throughout construction to maintain essential flood protection measures. High volume pumps will also remain in the reservoir to manage water levels until the end of the restoration project.

Next month there will be an open day where the public can go behind-the-scenes of the project.

The open days on Friday July, 7 and Saturday July, 8 are both free and everyone is welcome however places do need to be booked in advance.

The event is being organised by the Trust and contractors Kier, the open days will be held next to the site cabins by the Whaley Bridge Athletic Football Club and will give visitors a chance to walk onto the dam wall for a great panoramic view of the new spillway construction project.

Project engineers will also be on hand to explain details of the scheme in more detail.To secure a place visit the Canal and River Trust website: canalrivertrust.org.uk/restoring-toddbrook-reservoir.