Collapse of 200-year-old Wakefield weir ‘potentially imminent’ unless repairs completed
Experts have warned that a 200-year-old weir could collapse unless strengthening work on the historic structure is carried out.
Repairs works required at the Grade-II listed weir at Kirkthorpe, in Wakefield, were identified almost a decade ago but have yet to be completed, according to a report.
The structure, on the river Calder to the east of the city, helps to control the flow of water into the Aire and Calder Navigation.
A hydropower plant was built next to the weir in 2016, which led to the sudden failure of its sluices.
A survey found indications of instability and scour – when water erodes the sediments that surround the base or support structures.
A report by the Canal & River Trust to Wakefield Council requesting permission to carry out the work said it was “concerned about the stability of the weir.”
The document states: “The aim of the proposed works is to re-establish the structural integrity of Kirkthorpe weir and prevent future scouring issues.
“This intervention is of crucial importance to safeguard the Grade II-listed structure in the long term as structural failure is a potential imminent risk.”
The local authority previously granted permission for the repairs to go-ahead in 2022 but the work was not carried out.
Details of the planned work are included in a re-submitted application made after permission expired in June this year.
A weir is a small barrier, or small-scale dam, built across a stream or river to raise the water level slightly on the upstream side.
They allow water to pool behind them, while allowing water to flow steadily over the top.
Kirkthorpe weir acts to maintain levels at Stanley Ferry, Birkwood Lock and back up the river to Fall Ings Lock in Wakefield.
Experts say the solution to fix the weir is to install a “sheet pile cut-off” at the toe of the weir.
They also propose installing rip rap – a layer of large stones – acting as scour protection.
The existing weir and its sluices were constructed in 1827 and granted listed status in 1986.
An earlier weir was built at Kirkthorpe in the early 18th century following an Act of Parliament, passed in 1699, to improve the navigability of the Calder between Wakefield and Castleford.
The structure is jointly-owned by the Canal & River Trust and the council.
The site comprises a stepped and curved stone weir with three sluices positioned across the river.In 2015, the council granted permission to Yorkshire Hydropwer Limited to build and operate a new hydropower station adjacent to the weir.
The hydropower scheme utilises the flow of the river to generate approximately 2.3 million units of electricity per year.
It was noted during its construction in September 2016 that the central sluice pier had shifted, subsiding into a scour hole that had formed rapidly within the riverbed beneath it.
Remedial work was carried out to brace the structure.