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.
Work continues on the important temporary repair project to enhance the resilience of Toddbrook Dam’s auxiliary spillway. Stringent working conditions have been introduced to protect staff against coronavirus, including the use of extra protective equipment and ‘social distancing’ rules.
The effectiveness of the dam’s waterproof clay core has been improved by the installation of a concrete ‘cut off beam’, completed at the end of March. This will be further enhanced by the installation of a crest wall in late April. Sturdy concrete waterproof barriers will be constructed on the spillway slope to channel any overflowing water into the central undamaged section.
The new features will ensure that the spillway is secure in any extreme weather events. They will remain in place until permanent reconstruction of the auxiliary spillway is undertaken – a project which is likely to take several years and cost around £10 million.
The record rainfall totals in February caused major delays to the construction project and provided a severe test for the pumping system. Everything worked as it should. Our 11 high volume pumps were highly efficient in keeping water levels very low and the reservoir almost drained.
Work to install the clay core ‘cut off beam’. A rail and bogey system has been introduced to reduce manual handling
Over the next few weeks we will be repairing boundary walls and clearing vegetation.
In late spring, the temporary works to the dam will be followed by improvements to the Todd Brook inlet structures at the head of the reservoir. This will provide greater control over how much water flows from the brook into the reservoir or around it via a bypass channel. During normal weather conditions, while the reservoir remains drained, all flow is sent down the bypass channel ie, none into the reservoir.
Two independent inquiries have been commissioned into what happened last August.
These are published in full here:
The Canal & River Trust welcomes the Government-commissioned Independent Reservoir Review report from Professor Balmforth which examines the cause of the damage to Toddbrook Reservoir last summer and makes recommendations for the improvement of reservoir safety across England and Wales.
Both the Balmforth report and a separate independent report by expert reservoir engineer Dr Andrew Hughes, commissioned earlier by the Trust and also published today, identify that serious hidden design flaws, inherent in the concrete auxiliary spillway from the time of its installation in 1970, caused its partial collapse on 1 August 2019 following several days of heavy rainfall.
Since the incident last August, the Trust has implemented measures to enhance reservoir inspection and maintenance and will now be fully reviewing both reports and acting on their findings to ensure the ongoing safe stewardship of the reservoirs in its care.
The events last summer, although happening after heavy rainfall, were unexpected. At no point in the Toddbrook spillway’s 50-year history were design flaws identified; successive inspections by independent Engineers - from the Government-appointed All Reservoir Panel, in accordance with the Reservoirs Act - did not raise any questions about its design until the most recent independent inspection report. This was received by the Trust only three months prior to the incident and did not identify an immediate threat to safety, or direct that any urgent precautionary measures be taken.
The Trust acknowledges that maintenance of the spillway in some periods of its 50 year life – including pre-2012 under Government-owned British Waterways – might have been more stringent; although both Professor Balmforth and Dr Hughes conclude that the inherent design flaws mean that it is very likely that the spillway would have failed in an extreme weather event regardless.
Richard Parry, chief executive of the Canal & River Trust, comments: “I welcome the publication of the independent report into the cause of the spillway failure at Toddbrook reservoir last summer, and its recommendations to enhance safety across all reservoirs in England and Wales. Keeping people safe is always our top priority; we welcome any steps that reduce risks to local people and are fully committed to acting on all the lessons learnt from this incident and taking the actions arising from both these reports.
“Once again, I would like to thank the emergency services for their heroic efforts last summer, the residents of Whaley Bridge who have coped magnificently with the disruption, together with the Trust’s employees, volunteers and partners. The Trust has begun preliminary work on repairing Toddbrook reservoir prior to its full restoration, and we remain fully committed to liaising closely with the local community as our repair work progresses.”
Recent improvements made by the Trust include:
The Canal & River Trust’s reservoirs and waterways are a vital element of the UK’s infrastructure, and the reports published today provide an important opportunity for all reservoir owners to learn from what happened to ensure the highest standards of public safety in the future.
We're currently working to enhance the resilience of the Toddbrook auxiliary spillway following damage caused in August 2019 after heavy rainfall.
The temporary works to the dam will be followed by improvements to the Todd Brook inlet structures at the head of the reservoir. This will provide greater control over how much water flows from the brook into the reservoir or around it via a bypass channel. The project includes installing a new footbridge across the inlet weir.
As the charity that cares for Toddbrook Reservoir and 2,000 miles of waterways across England and Wales, we're working closely with contractors Kier to keep the reservoir drained as preparations are made for its long-term repair – a process that is likely to take several years and cost around £10 million.
From 6 January 2020, temporary works are being carried out on the dam’s auxiliary spillway, which was damaged in the summer of 2019. A protective, waterproof nib (short wall) will be inserted all along the spillway crest which will reach down into the dam’s clay core.
The spillway crest will be increased in height by just over one metre at either end and sturdy concrete waterproof barriers will be installed on the spillway slope to channel any overflowing water into the central undamaged section – which will be lined for extra protection.
The new features will ensure that the spillway is secure in any extreme weather events. They will remain in place until permanent reconstruction of the auxiliary spillway is undertaken.
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 north west 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. In 2020, these will be replaced by a new structure, potentially incorporating a footbridge, to provide a greater degree of control over water flows.
The Trust will continue to monitor the bypass channel closely. During normal weather conditions, while the reservoir remains drained, all flow is sent down the bypass channel ie, none into the reservoir.
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.
Our weekly surgeries, held every Wednesday at the Transhipment Warehouse by the canal basin, have been suspended until further notice due to the coronavirus.
However, you can still contact the Trust or get in touch with our Whaley Bridge community liaison manager, Gillian Renshaw, by emailing: email@example.com.
The Canal & River Trust has sponsored new sports shirts for the Whaley Bridge Football Club Under 12’s team as a ‘thank you’ for the club’s incredible contribution towards the Toddbrook Reservoir dam repair works.
Part of the club’s grounds, off Park Road, have been occupied by construction site cabins, installed by the Trust and its contractor Kier as a base while the damaged reservoir dam wall is repaired.
Trust engagement manager Gillian Renshaw said: “Everyone at Whaley Bridge Football Club has been fantastic and made us feel so welcome. From chinooks landing on their playing fields during the emergency last August to the inconvenience of the long-term repair project, the club’s volunteer organisers and players could not have been more helpful.
“This is a situation that none us wanted or envisaged but we are trying our best to fix everything – a job which is made so much easier with the understanding and support of the club. We are delighted to show our appreciation of their efforts by sponsoring their Under 12’s new kit.”
Whaley Bridge AFC development officer John Hind said: “For the Junior Football club, it has been a challenging first season without a pitch and we are indebted to Furness Vale FC and Chinley FC for their help. We have enjoyed tremendous support from the local community who have continued to rally around after the events in August. We would like to thank the Canal & River Trust, Kier and also High Peak Borough Council, ‘Ditch your Goretex’ ‘keep your chinook up’ discount football kits, Tesco and Waitrose supermarkets for their donations to the club.”
Photo shows Canal & River Trust Whaley Bridge engagement manager Gillian Renshaw (back centre) with Whaley Bridge AFC Under 12s team, proudly sporting their new football kit. Whaley Bridge AFC development officer John Hinds is back row far left.
|Construction||Built in 1830s. Opened in 1840 as a feeder for the Peak Forest and Macclesfield canals|
|Volume:||1,238 megalitres – equivalent to 495 Olympic-sized swimming pools|
|Dam wall height:||23.8m|
|Environmental status||Site of Special Scientific Interest (SSSI)|
Last date edited: 31 March 2020