Authorities ‘should have been better prepared for floods’
THE flooding that hit Stockport after ‘ unprecedented’ rainfall last year could have been less devastating had the authorities been better prepared, according to a new report.
It also finds that ‘design shortcomings’ mean the A555 Manchester Airport Relief Road - which was closed several times during the four-day deluge in July 2019 - will ‘remain vulnerable to flooding from prolonged or frequent heavy rainfall’.
The four consecutive days of ‘torrential and intense’ rain at the end of July - expected once in 266 years - caused an estimated £1m of damage to homes and businesses in the borough.
The worst-hit areas included Bramhall, Cheadle Hulme and Hazel Grove as the Micker Brook and Poise Brook burst their banks and the drainage system failed to cope with the sheer volume of water.
The misery inflicted on residents led to Stockport council commissioning consultants Mott Macdonald to carry out an independent review into why the flooding happened and what measures could mitigate it in future.
While the review is clear that rainfall was ‘severe across a wide swathe of the borough’ and some flooding was inevitable, it adds that safeguards were not what they might have been.
The criticism includes the responsible ‘risk management authorities’ (RMAs) including Stockport council, the Environment Agency, United Utilities and Highways England - as well utility and infrastructure providers such as Network Rail and the Canal and River Trust.
It states: “RMA actions in the July 2019 event appear to have been largely reactive Some reduction of flooding may have been achieved had critical structures been checked for blockages and where necessary maintained either in response to severe weather forecasts or as a part of regular planned work in readiness for the summer downpours that the area appears vulnerable to.”
Furthermore, it was found that not all the recommendations from a report on the serious flooding of 2016 had been acted on.
Mott MacDonald says it has not seen any evidence that the Environment Agency had taken steps towards reducing flooding from Lady Brook, at Bramhall Green, Hazel Grove Brook or Poise Brook.
And Network Rail is still to carry out the ‘crucial clearance’ of a culvert in Adswood Road, despite having been ‘aware of the problem for a number of years’.
The council is also yet to look into improving highway drainage in the Kintore Avenue area Hazel Grove, or review its management of road closures during flood events.
However the report acknowledges the authority ‘has pursued many worthwhile flood risk management actions that were not in the recommendations from 2016 which likely to have been of value in mitigating impacts in the July 2019 flooding event’.
One of the main highways issues was the A555 Manchester Airport Relief Road, which was hit by closures over the duration of the four-day weather event.
The investigation found there were problems with the road’s drainage network - with pumps being overwhelmed and storage ponds overflowing - but that this mainly affected the highway itself, and had ‘little effect’ on downstream flooding.
A pumping station at Hall Moss Lane - part of a section known as ‘Network E’ - was operating with one temporary pump, which was supplemented with additional ones as events unfolded and conditions allowed.
However, contrary to local suspicions at the time, the report says that no water was diverted from the usual route ‘ie there was no temporary pumping into Lady Brook from the A555’.
A series of recommendations are made in the report, which says that correcting construction defects would ‘improve the drainage system and can be expected to reduce the incidence of flooding’.
But, whatever steps the council and other authorities take in light of the findings, the report’s executive summary warns there is no silver bullet for Stockport’s flooding problems.
“Each flood incident represents considerable disruption and hardship for affected residents and each resident seeks a solution,” it states.
“But in many cases there are no quick or easy wins, solutions will need to be evaluated to ensure the actions are appropriate, effective and affordable.”
The draft report will be discussed by the council’s scrutiny and area committees at the end of September.
There will also be virtual meetings held online in which residents will be able to register to attend.