We are currently working on a major project to restore Toddbrook Reservoir after the dam auxiliary spillway was damaged in August 2019 after a period of intense rainfall.
Many thanks to everyone who took part in the three week public consultation into options for restoring Toddbrook Reservoir. Over 1,000 people visited the virtual consultation room online and 151 attended the drop-in events held in Whaley Bridge on 18 and 19 September. We are grateful to everybody who filled in a feedback form and gave their views.
The Trust, together with its specialist design consultants Arup, will now be examining all the comments and feedback. We intend to publish a report in mid-October to outline the design and development process to date, specifically explaining why two preferred options were chosen and others discounted.
A couple of mapping errors in the details presented in the consultation materials have been pointed out, for which we apologise. These have been corrected and only the corrected versions will be considered in our further design work.
A summary of feedback from all the consultation responses will be published on the website by the end of October 2020.
Public safety and compliance with the strict requirements of the Reservoirs Act will be our top priority, ensuring the reservoir is restored with the benefit of the best 21st century engineering expertise.
Over the next couple of months we will be completing a number of ground investigation and environmental impact assessments. Reservoir safety, technical constraints, access, buildability, community and environmental impact, planning, cost and green energy potential will all help to shape the important decision on the chosen repair option.
Once the preferred option is confirmed, a full report explaining the Trust’s decision will be published around the end of November.
Work will start on site, initially at the Todd Brook inlet, in spring 2021. This major project is likely to take about three years to complete. The high-volume pumps will remain in situ and water levels kept very low until the repair project is finished in 2023.
Toddbrook Reservoir normally provides just over a third of the water supply needed to keep the beautiful Peak Forest and Macclesfield canals operational. It is essential we repair the reservoir to secure the long term future of the canal network in High Peak and East Cheshire.
The footpath along the northern side of the reservoir, next to the bywash channel, opens to the public again from Saturday 3 October for a few months. No construction work will take place over winter, allowing this part of the site to be de-restricted, but the path will have to be closed again when work resumes in the spring. Due to safety concerns, it will be necessary to keep the footpath over the dam bridge closed throughout the project until the reservoir restoration is completed in 2023.
As part of the first phase of restoring Toddbrook Reservoir, an important repair project to the dam’s damaged auxiliary spillway has now been completed, greatly increasing its resilience against extreme weather events.
A protective, waterproof nib or short wall has been added to the crest of the dam wall above the damaged spillway. This reaches down to create a seal with the dam’s clay core and ensures no water from inside the reservoir can penetrate beneath the concrete slabs at the top of the spillway.
The spillway crest has also been increased in height by just over one metre with the installation of a sturdy waterproof concrete wall. Engineers completed the job with the installation of new pressure relief holes and joint repairs on the spillway.
Arup’s role will be to devise a solution to upgrade the existing overflow system, increase drawdown capacity, improve dam stability and address other recommendations made to improve reservoir safety following the 2019 incident.
Rachel Sandham, Project Director at Arup, said: “The disruption experienced by the community last year was deeply unsettling, but our work will ensure the longevity of the dam to keep residents downstream safe. We will be working closely with the Canal & River Trust to ensure that local residents are involved in the process and we are already exploring options of virtual consultations, should social distancing measures need to remain in place in the longer-term.”
Toddbrook Reservoir is fed by a stream, Todd Brook, which is diverted at the head of the reservoir to either feed into the reservoir or along a bypass channel. The bypass channel runs along the northwest edge of the reservoir before feeding directly into the River Goyt.
After the emergency in August 2019, the masonry weir at the inlet channel was raised with the installation of mesh baskets filled with sandbags.
Starting in spring 2021, the plan is to replace these with a new structure, incorporating a footbridge, to provide a greater degree of control over how much water flows from the brook into the reservoir or around it via the bypass channel.
During normal weather conditions, while the reservoir remains drained, all flow is sent down the bypass channel ie. none into the reservoir. Expert hydrologists are constantly monitoring localised weather forecasts and water levels in the reservoir and bypass channel via a series of remote sensors. They can then alert colleagues if the on-site pumps need to be activated or sluice gates opened.
Following intense heavy rainfall at the end of July 2019, several concrete panels on the Toddbrook dam spillway collapsed. Around 1,500 residents of Whaley Bridge were evacuated from their homes for up to six nights as a safety precaution. Trust staff and volunteers worked around the clock with the local emergency services, including Derbyshire Fire & Rescue, Derbyshire Police and the Environment Agency, to stabilise the dam wall.
Over a billion litres of water were pumped from the reservoir during this emergency phase and water levels continue to remain nearly empty while the dam is repaired. This is likely to take several years.
You can contact the Trust or get in touch with our Whaley Bridge community liaison manager, Gillian Renshaw, by emailing: firstname.lastname@example.org.
Last date edited: 1 October 2020