
Blocked drains were not responsible for causing flooding to dozens of homes and businesses in a North Yorkshire town, a report has concluded.
More than 50 properties were affected after heavy rain caused flash flooding in Knaresborough on May 6 last year.
Residents were forced to evacuate their homes, with some unable to return for several months.
After the incident, householders blamed blocked drainage gullies for causing the flooding.
But a North Yorkshire Council report concluded that while some gullies in the town had been blocked for some time, this was not a reason for the flooding.
Site visits conducted by highways staff after the incident found that only a small number of gullies were under-performing due to blockages.
The document said:
“Given the drainage networks were already beyond capacity and were not allowing any further surface water to enter their
systems, the apportionment of blame on the non-operational gullies is likely to be less than expected and cannot be ruled as a clear reason for the flooding or that the flooding was amplified due to these non-functional gullies, in such an extreme event.”
The report said that in flash flood conditions, gullies could become ‘blinded’ — meaning debris on top of the drain stops surface water entering the system.
Blinded gullies were found in the flooded areas including Blind Lane, near Orchard Close.
Blockages found in Yorkshire Water’s sewer network in two small-diameter sewers in St Margaret’s Gardens and Queens Road were also not to blame, the report said.
It said:
“The drainage system failed to convey water away quickly enough to avert the flooding as it is simply not designed with the capacity to cope with the amount of water which was present, and as such no further capacity assessments are necessary as a result of the one in 516 year event.”
The report, which will be discussed by senior officers and councillors from the council’s environment directorate next Friday, made a number of recommendations including working with communities to improve resilience.
It also suggested that Yorkshire Water and North Yorkshire work together to separate surface water and foul drainage by promoting the use of sustainable drainage systems.
Knaresborough resident Mark Robinson and his family were left homeless after their house was flooded.
He was critical of the report’s findings saying he believed the drains would have been cleared more regularly if Harrogate Borough Council still existed.
He added:
“No one seems to want to take responsibility for this happening but are happy to blame each other.
“No one would take accountability for this, meanwhile my family were made homeless for approximately five months.”
Mr Robinson paid tribute to Chain Lane Community Hub for their help to residents at the time of the flooding.