The Canal & River Trust has today shared the findings of its interim investigation into the Llangollen Canal breach that occurred at Whitchurch, Shropshire, last December.
Prepared by Canal & River Trust engineers, supported by technical experts, the initial findings suggest the breach was most likely caused by a combination of specific factors in this location. This included a long-term, deep-seated leak beneath the canal bed that was undetectable to the Trust’s inspection regime, combined with a steep-sided, high embankment predominantly constructed of sand. This long-term leakage is thought to have eroded material below the canal bed and created a void, ultimately resulting in collapse.
The investigation, which continues as the site is drained and cleared, has not identified other factors at play such as heavy rainfall, overtopping, fallen trees or animal excavations. Final conclusions cannot be drawn until the site has been fully cleared and the investigation completed, including inspections of two nearby culverts which are currently not thought to be contributory factors.
Campbell Robb, Canal & River Trust chief executive, said: “The breach at Whitchurch was a distressing and frightening experience for all those affected. We remain deeply sorry for the impact this event has had on boaters and the wider community and once again I’d like to thank all who responded so swiftly and generously when this event happened. We are committed to repairing the canal and reinstating navigation as soon as we can do so safely.
“While breaches of this scale remain extremely rare, we are already taking forward a number of recommendations from the investigation. We have a comparable inspection regime to organisations looking after similar infrastructure but we are augmenting this, including exploring different methods of geophysical surveying technology to better inspect beneath canal beds.”
Although it will take most of the year, the Trust is already progressing the repair of the canal, getting the navigation back open as quickly as possible. This includes completing a key 100-metre-long access track across farmland from the A41 which will be used to bring in c20,000 tonnes of aggregate needed to rebuild the canal’s embankment. Construction is likely to start this spring once in-depth ground investigation works are complete as part of due diligence to confirm the design of the embankment rebuild. Last week, an important ecological milestone was also achieved with the rescue and safe return to the canal of around 1,000 fish that had been washed into the large pool of water that formed in a neighbouring field.
The full investigation is still ongoing and will be completed and published in the coming months. Its ultimate purpose will be to improve the Trust’s and other historic infrastructure resilience by identifying what may have contributed to the embankment failure and how it can be mitigated.
