DAM FINE WORK
TEMPORARY REPAIR COMPLETE ON RESERVOIR WHICH FACED DISASTER
ENGINEERS have completed a temporary repair of the Toddbrook
Reservoir dam almost a year after it partially collapsed and threatened to inundate Whaley Bridge.
More than 1,500 people were evacuated from the picturesque Derbyshire town when the spillway began crumbling during heavy rainfall in early August last year.
A huge emergency operation involving the RAF and hundreds of firefighters and police officers saw the damaged wall shored up with hundreds of tonnes of aggregate while the reservoir was hastily drained.
Professor David Balmforth, a reviewer of reservoir safety, blamed ‘poor design’ and ‘intermittent maintenance over the years’ for the failure of the dam in his report about the breach in March.
Engineers have now revealed the temporary repair of the damaged spillway has been completed.
The dam’s waterproof clay core has been made more effective by the installation of a concrete ‘cut off beam’ and an enhanced crest wall along the top of the dam to protect against extreme downpours.
These new features will remain in place until the end of the permanent reconstruction project.
A final design has not yet been decided, but engineers expect it will cost £10m and take three years.
The Canal & River Trust charity, which cares for the reservoir and 2,000 miles of waterways, has worked with contractors Kier through record winter rainfall and the coronavirus crisis to increase the resilience of the dam’s auxiliary spillway.
The temporary repair has been completed save for the installation of new pressure relief holes and joint repairs.
Any excess rainwater falling in the reservoir continues to be removed by pumps and it will remain drained until the permanent reconstruction project is finished in around 2023.
Once this first repair phase is completed, the construction site boundaries will be reduced and some footpaths around the reservoir will be reopened to the public for a few months until spring 2021, when the permanent repair works are expected to begin.
Daniel Greenhalgh, Canal & River Trust north west regional director, said: “We are delighted to have completed this first phase in the restoration of Toddbrook Reservoir. We have had to cope with some challenging operating conditions but we can confirm the dam spillway is totally secure against any extreme weather event.”
He added: “We are currently examining a range of potential repair options and the views of local residents are a key part of the decision-making process. We are planning to host a public consultation event in late summer and then confirm the preferred option in the autumn.
The first phase of the permanent works will begin in spring 2021 at the Todd Brook inlet channel at the head of the reservoir.