UNUSUAL ‘THREE-SIDED’ DAM ALLOWS NAVIGATION AT HOLLOWFORTH AQUEDUCT

30 September 2024

UNUSUAL ‘THREE-SIDED’ DAM ALLOWS NAVIGATION AT HOLLOWFORTH AQUEDUCT

A monumental effort, including construction of a three-sided dam, by the local Canal & River Trust team has enabled boaters on the Lancaster Canal to navigate across Hollowforth Aqueduct following a breach at the aqueduct earlier this summer.

On 20 July, the Trust’s emergency team responded to a breach of the canal at the Grade II-Listed Hollowforth Aqueduct. The damage was extensive and affected both the embankment and a section of the aqueduct, requiring substantial and expensive repairs. The charity’s local team acted quickly to install temporary dams across the canal to isolate the breach, preventing further water loss, and protecting the canal and surrounding areas from further damage.

With the canal route and water supply temporarily severed by a dam either side of the breach site, one of the initial priorities was to install bypass pumps to ensure a water supply to keep boats afloat. Beyond that, the Team’s priority turned towards the long-term repair of the breach and how, if at all possible, to create an immediate navigable channel for boaters wanting to cross the aqueduct to continue their journeys.

A three-sided dam around the breach site, which would allow controlled navigation between the north and south of the breach for those boats that needed to move, was designed. In preparation for the dam, clay was carefully placed in the canal bed, creating a solid foundation. Silt samples indicated high levels of metal contamination, so the silt had to be removed before boats could pass. Once the dam was in place, a dredger boat passed through, clearing and testing the way for other boats to ensure it was safe. On 26 September, the aqueduct reopened for controlled boat passage until 3 October.

The works to date have required input from multiple teams across the charity. A topographical survey is needed to confirm that the embankment is safe for reinstatement and, with the canal structure Listed, the design of the repair requires Listed Building Consent. Similarly, environmental legislation has required a bat survey to determine that there aren’t bats roosting within the aqueduct.

Away from the immediate breach, 500 metres of stock-proof fencing has been put up to ensure that livestock are kept away from the work site, and several trees have been removed to provide access. Additionally, the site compound has been reinforced with stone, making it ready to accommodate the heavy machinery that will be required for the repair work.

The Trust’s engineers have completed a first engineering design for the final repair work. The works will be finished in 2025, with an end date dependent on whether building consent is required.

Jon Horsfall, regional director at Canal & River Trust, said: “Completing the repairs to re-open the navigation for our boaters and all others who enjoy the canal is a priority, however they are complex and will take several months to complete. We’re glad to have been able to find a temporary solution for those boaters who needed to cross Hollowforth Aqueduct in the meantime.

“Our design team, along with our geotechnical engineers, have been on the ground putting together a solid plan to rebuild the embankment and the damaged aqueduct. We’ve also been busy with ecology and heritage surveys, and we’ve agreed on a plan that respects and protects the historical aspects of the site.

“The Lancaster Canal is going to be 200 years old in two years’ time, but centuries of use and battering by the elements have taken their toll, and the work to repair the breach will take significant funding. We’re doing all we can to get the canal back open as quickly as possible, and we welcome support from all parties.”

To support Canal & River Trust, please visit: Support us | Canal & River Trust (canalrivertrust.org.uk)

To find out more about the repairs at Hollowforth Aqueduct, please visit: Lancaster Canal, Hollowforth Aqueduct. | Canal & River Trust (canalrivertrust.org.uk)

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For further media requests please contact:

Fran Read, Canal & River Trust

m 07796 610 427 e fran.read@canalrivertrust.org.uk

Fran Read (she/her)

National press officer

I work Mondays, Tuesdays, Thursdays, and Fridays

M  07796 610 427

E  fran.read@canalrivertrust.org.uk

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