Devastating flooding which left dozens homeless and caused damage valued at three-quarters of a million pounds was made worse because river authorities mothballed a sluice gate a mile downstream.
That was the claim yesterday from an independent flooding expert, who was commissioned by civic leaders in Malmesbury, Wiltshire, to come up with quick fixes to the problem of flooding at the bottom of the town's ancient High Street.
Last October and November, the two branches of the River Avon burst their banks in the town in the worst floods in living memory. The Environment Agency pledged to undertake a major study of what could be done, but warned any action could take years to research and implement.
So the mayor at the time, town councillor Ray Sanderson, set up a group of people to come up with their own ideas. Next Monday they present their findings.
The town council-led study included work by independent flood-risk management expert Edward Evans, who said it is possible the floods in the town had been made worse by changes to a weir system a mile downstream.
"In the past, the main river flowed through the Cowbridge Sluice feeder channel and the sluice was operated regularly by the Environment Agency after the mill was abandoned," his report said. "However, it was very labour-intensive to operate and the EA ceased operating it and built the present Cowbridge Weir.
"It was very striking during the site inspection how flat and slow moving the water was downstream of the confluence of the two branches of the Avon, clearly being ponded up by Cowbridge Weir," he added.
The report said that when the sluice gates at Cowbridge were opened, river levels dropped significantly, leading residents and councillors to believe that, while the floods were inevitable, they were made worse because it was initially closed.
Now, council chiefs are working on signing an agreement with the present owners of the sluice – a housing developer called Mintons, which has turned a former office complex into homes – to open the sluice regularly during the winter.
"We are formulating operating rules for agreement with the EA with a view to getting the sluice back into operation for the coming winter," said Mr Sanderson. "We have met the former operators to pick their brains on the weir and sluice and the operating rules."
Residents flooded out of their homes have only recently been allowed back, although some have refused and have settled elsewhere.
As well as the sluice issue, the study concluded a number of other short-term measures, including lowering a footpath, clearing out the area under the Town Bridge, realigning a river wall and cutting a channel across a nearby meadow, could reduce the risk.