‘Long road ahead’ in reservoir restoration
MAINTAINING water supplies for boating on the Peak Forest Canal looks set to become a challenge over the next few years in the wake of the Toddbrook Reservoir emergency.
The news came in a meeting held by Canal & River Trust to give an update on progress at the site above the town of Whaley Bridge in Derbyshire.
On July 31 last year there was heavy rainfall across Derbyshire and the Peak District, resulting in Toddbrook reservoir becoming very full and excess water flowing over the spillway on the dam wall.
For some as yet unknown reason, part of the concrete covering the spillway broke away and exposed the clay and soil dam beneath it.
With the integrity of the dam possibly compromised, large parts of the town were evacuated while the levels in the reservoir were reduced by 12 highcapacity pumps moving water out into the River Goyt.
The reservoir is now nearly empty of water and plans are progressing towards a permanent repair and eventual return to use to provide water to the Peak Forest Canal.
The latest update was through a media day at the reservoir and a public meeting in Buxton, which was attended by nearly 100 people.
At present, the meeting heard, the reservoir is nearly empty and the flow of water from the main source, Todd Brook, has been diverted around the reservoir down the bypass channel into the River Goyt.
The pumps that emptied the reservoir are still in place, with one on an automatic system to pump if the water level rises following heavy rainfall.
The restoration works will see a temporary waterproof wall erected along the spillway crest, which will reach down into the dam’s clay core. This will be followed by the installation of sturdy concrete barriers on the spillway slope to channel any overflowing water into the central undamaged section.
This will all remain in place until permanent reconstruction of the dam is undertaken.
Improvements were also to be made to the Todd Brook inlet channel at the head of the reservoir.
After the emergency in the summer, the masonry weir was raised with the installation of mesh baskets filled with sandbags. In the year ahead, these will be replaced by a footbridge incorporating sluice gates, providing a higher degree of control over water flows from the brook into the reservoir or around the reservoir via a bypass channel.
New footbridge
A new pedestrian footbridge across the brook will also be built to create a safe route for people wishing to walk from one side of the valley to the other.
The fate of Toddbrook reservoir’s fish population is a positive one. The week before Christmas a third rescue was undertaken to net as many as possible before the reservoir was drained further, which would have left them unable to breathe in the lower oxygen and higher silt environment.
This followed successful fish rescues in August and October when thousands of coarse fish – bream, roach, perch and pike – were captured in large nets and then transported to another trust reservoir near Birmingham.
Before the incident it was understandably a popular angling spot.
In total it is estimated that about 30,000 fish, equating to five tonnes, will have been rehomed by the end of the process.
There are two separate independent enquiries ongoing, one commissioned by CRT and the other by the Government.
Once these have reported, a longterm plan will be developed to repair the dam.
Simon Bamford, asset improvement director for the trust, said: “Once we know what caused the damage to the dam we will be able to work out a detailed plan for repairing it, including a precise timetable and costings.
“At the head of the reservoir we know a footbridge has been on the wish list of some local residents, so we are delighted we can incorporate this into the design for improving the inlet.”
It is anticipated that the full works to make the reservoir able to once again supply the Peak Forest Canal could take several years and cost around £10 million.
Daniel Greenhalgh, CRT’s North West regional director, said while the priority was keeping Whaley Bridge and its residents safe, this might not be great for boaters, following on from the last two years of lock rebuilding on the Marple flight, as there would be a real challenge over the next few years of maintaining water supplies on the Peak Forest Canal, with restrictions in lock usage likely.
Julie Sharman, chief operating officer with the trust, said: “More public open days are planned for the spring and we will be sending a newsletter to more than 3000 Whaley Bridge homes to explain about the repair works.”
The Canal & River Trust described the works as “a long road ahead for the restoration and reinforcement of the Toddbrook Reservoir”.