Specialist Piling Supporting a Major Flood Defence Project
Seven years ago, in August 2019, Toddbrook Reservoir in Whaley Bridge became the focus of a major emergency.
Following a period of extreme rainfall, the reservoir’s auxiliary spillway was overwhelmed, with sections of the concrete structure failing as water cascaded down the dam. With concerns over the integrity of the reservoir and the potential consequences for the town below, around 1,500 residents of Whaley Bridge were evacuated while water levels were reduced to a safe level.
The dramatic events made national headlines and highlighted the importance of maintaining and upgrading critical water infrastructure.
Fast forward seven years, and the long-running restoration project is now entering its final stages. The reservoir is slowly being refilled as work nears completion, with the aim of returning it to full operation and restoring its important role in supplying water to the Macclesfield and Peak Forest Canals.
A major engineering challenge
Built in the 1830s, Toddbrook Reservoir sits in the High Peak area of Derbyshire and covers approximately 36 acres, with a capacity of around 1.3 million cubic metres of water.
Following the 2019 incident, a multi-million-pound remediation scheme was developed and led by the Canal & River Trust. The project involves replacing the failed spillway arrangement with a new side channel weir, tumble bay and spillway system designed to safely manage excess water and discharge it towards the River Goyt.
During the emergency response in 2019, more than 600 tonnes of aggregate stone and around 10,000 sandbags were dropped by Chinook helicopters to help protect and stabilise the dam while the reservoir level was brought down.
The subsequent permanent works presented a very different challenge: delivering a complex new water management structure within a sensitive environment, while maintaining stringent controls over noise, vibration and construction activity.
This is where specialist piling played an important role.
Ivor King’s role on the project
Ivor King – The Piling People were proud to play a significant part in the Toddbrook Reservoir remediation scheme, providing piling design services and specialist installation expertise across a number of phases of the project.
Our scope included the installation of both temporary and permanent steel sheet piling, together with concrete bored piles supporting the new structures.
In total, around 1,000 steel sheet piles, up to 12 metres in length, were installed using a combination of leader-rig and excavator-mounted piling equipment, including vibratory and impact hammers.
The piling works were undertaken with strict control measures in place to ensure that specified noise and vibration limits were maintained. Working within a live project environment close to the local community, minimising disruption was a key consideration throughout the works.
Forming the new spillway
One of the principal applications for the sheet piling was the new spillway chute.
The sheet piles form part of the structure designed to safely divert excess water from the reservoir towards the River Goyt through the new side weir and stilling basin.
The new arrangement is designed to reduce the energy of flowing water as it leaves the reservoir, providing a controlled route for discharge during periods of high water levels.
Installing the piles accurately and efficiently was therefore a critical part of constructing the new system.
Deep foundations for the tumble bay
Alongside the sheet piling, Ivor King also installed concrete bearing piles to provide foundations for the new tumble bay.
Around 430 concrete bearing piles were installed using the Continuous Flight Auger (CFA) piling technique, with the piles reaching an average depth of approximately 20 metres.
A further 50 bored piles were installed to form the turrets either side of the stilling bay.
A cofferdam for the deep excavation
The construction of the new tumble bay also required significant excavation.
To facilitate these deep excavations safely, a sheet pile cofferdam was installed around the work area, creating a secure temporary working environment.
The temporary works also included steel walings fabricated at Ivor King’s main facilities, demonstrating the benefit of our in-house fabrication capabilities and our ability to provide an integrated piling solution.
Importantly, the sheet piles forming the cofferdam were designed to be incorporated into the permanent structure, helping to maximise the value and efficiency of the installed materials.
A project requiring specialist expertise
Toddbrook Reservoir presented a combination of technical, environmental and logistical challenges.
Working on a major water infrastructure project in the aftermath of a significant reservoir incident required careful planning, precise installation and close attention to the surrounding environment.
From the installation of more than 1,000 sheet piles to the construction of almost 500 CFA and bored piles, Ivor King’s involvement covered a range of specialist piling techniques and applications.
The project also demonstrates the versatility of piling as a construction solution – from forming permanent structures and deep foundations to creating temporary cofferdams that allow complex works to be carried out safely.
Looking back – and looking ahead
Seven years on from the emergency that led to the evacuation of Whaley Bridge, Toddbrook Reservoir is now approaching an important milestone.
As the reservoir slowly refills and the restoration works move towards completion, the new infrastructure will play a vital role in ensuring the reservoir can once again operate safely and fulfil its original purpose.
For Ivor King, the project is another example of how specialist piling expertise can contribute to the delivery and restoration of critical UK infrastructure.
Our case study video, filmed in 2023, provides a closer look at the works carried out by our team at Toddbrook Reservoir, including the installation of the sheet piles, CFA piles and temporary works.
Take a look at our Toddbrook Reservoir Case Study video to see the Ivor King team in action.
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