By Paul Reoch

A FLOOD defence expert appointed by Perth and Kinross Council has said that a £500,000 scheme in Milnathort was “adequate,” despite it being breached almost a year ago.

Dozens of residents of the Kinross-shire village were forced to flee their homes on December 13 when the Back Burn burst its banks.

Several householders—some of whom have still to return to their homes—have hit out at the council’s response to the flood, with some even considering taking legal action.

Initially, the council instructed Arup Scotland, which had built the scheme at Milnathort, to investigate the flooding.

Its report, compiled and validated by consultant engineers Atkins, revealed it would have been at a “manageable level” if one section of embankment had been built to the right level.

The report said an earth bund at 5 Wester Loan collapsed, leading to the centre of Milnathort being flooded and around 40 residents having to leave home.

In the wake of subsequent fierce criticism, the council enlisted the services of Professor Richard Hey to review “the standard” of the existing flood defences and identify any possible “soft engineering” measures upstream that might help further reduce the risk of flooding.

Professor Hey is an expert in sustainable flood management and had been recommended to the council by WWF (World Wildlife Fund). His appointment was questioned by some villagers, with claims that he cost the council £1000 per day.

In his report he states that he finds the flood mitigation scheme at Milnathort to be adequate and the deluge last December was in “all probability” higher than the defences were designed to withstand.

Professor Hey’s report also asserts that the design was in line with national criteria, albeit that a small section of embankment had not been constructed to the correct level, and that the permanent repair of the existing scheme will reinstate the designed level of protection.

The study also identifies possible measures to increase the capacity to store flood water upstream of Milnathort that may be beneficial, but Professor Hey states the practicalities would need “further investigation.”

He says while he might have used some different “methodologies” and “assumption,” Arup’s design was to the required one-in-100-year level of protection.

In fact, he estimates that the level of flooding experienced in Milnathort may have exceeded a one-in-200-year event.

He said, “The cumulative effect of the heavy rainfall over the five days prior to December 13 would have resulted in much of the soil water storage and surface detention capacity of the catchment area being filled prior to the onset of the critical storm.

“This lack of upstream storage capacity, together with raised burn water levels, aggravated the flooding in Milnathort.”

The professor—whose report will be discussed at the enterprise and infrastructure committee on Wednesday—noted that after the flooding an investigation of the bed of the river upstream did not find any wood debris, and he casts doubt on the “speculation” in Atkins’ report that trapped debris might have reduced the flow area by 40%.

“The main source of floating material appeared to be garden waste and this has been brought to the attention of local people in order that they don’t inadvertently contribute to the risk of flooding,” he said.

The report states that the “run-off” from the M90 has added to the problem of limited space for the burn to convey floodwater. “It is proposed that Transport Scotland should be approached to address this matter.

“And although residents in Milnathort have asked for de-silting to be carried out, there is no evidence of significant bank erosion,” Professor Hey said.

“In addition, reducing the level of Loch Leven would not have affected the flood levels.

“However, the issue of surface water drainage in the village should be investigated and, if necessary, rectified before any further development is permitted. This is the responsibility of Scottish Water who have given an undertaking that this will be investigated.”

Professor Hay does not consider installing a flood warning system as it would give a “very limited” opportunity to react.

And he notes that a temporary solution to replace the failed bund is in place but that a permanent solution can’t be “progressed” until after April.

He concludes that once remedial works to the flood defence scheme have been completed, Milnathort will be protected to the standard originally agreed.

He advises “further discussion” be held with the Scottish Government to explore the availability of specific grant funding to investigate additional upstream “soft engineering” measures.

Jim Irons, the council’s executive environment director, said, “Given the number of communities who are still without any flood protection at all, I can’t recommend that resources be diverted to investigate these other matters at this time unless there is government grant funding for pursuing these measures on a trial or pilot basis.”

The costs of investigating the possibilities outlined to reduce the risk is estimated at £50,000, for which no budget exists.

John Kellas, the convener of the enterprise and infrastructure committee, said, “We will continue to do all we can as a council to take whatever steps are practical to improve flood defences across Perth and Kinross.

“Milnathort is one of a number of communities that have suffered the misery of flooding in recent years and I welcome this report’s confirmation that the existing flood defences at Milnathort will provide the specified level of protection.”