Yorkshire Water is to fund a study of a town’s drainage system where hundreds of homes were flooded last year.
More than 700 properties were flooded following the deluge on August 3 and there were calls for compensation after the firm admitted Carr Lane pumping station in the town temporarily failed.
A new report says three foul water pumps at the station shut down half an hour after the rain started falling.
Yorkshire Water says the pumps went into “failsafe” mode, because sensors were unable to determine water levels. The pumps were out of action for 72, 45 and 63 minutes respectively.
Two of the four bigger storm pumps were also out of action, one having been removed for maintenance, while the other had been “electrically isolated.”
Since the event residents and councillors have argued that this must have contributed to the scale of the flooding, but the report, written by engineers at East Riding Council, says it is “unknown” and a further study would be required to find out.
It says the unavailability of the two pumps meant the station’s capacity was reduced for an hour and a half, adding: “As the efficiency of the storm pumps or the volume of water they pumped during the storm is unknown, the effect this had on the volume of flood water is also unknown.”
But it insists that “even if the drainage system was “as new” and operated to a 100 per cent capacity, there would have been significant areas of flooding.”
It also reveals that because of a lack of accurate rainfall recording apparatus, it was impossible to say just how much rain fell. It is estimated that at least 30mm of rain fell in a 45-minute period, equating to a one in 45 year event. Anecdotally it is suggested more than twice as much, 64mm, fell.
Among a series of remedial and improvement works, the company has already altered the way the pumps work to ensure they don’t switch off as they did in August.
Both YW and the council are also recommended to look at building an extra sewer on Millennium Way to carry surface water to provide added protection, over and above a recently installed tank. Houses in the area are 4ft below the level of the road.
The council is also looking at the potential for protecting individual properties and bidding for funding from Defra so the recommendations can be carried out.
Goole councillor and Labour group leader Pat O’Neill said: “It is very disappointing. There is nothing there that is going to stop it happening again. Now is the time of year when people are seeing a substantial rise in their insurance premiums. This report won’t in any way console the flood victims.”
Coun Keith Moore added: “I am not surprised they are saying that the drainage couldn’t cope – because everybody has been saying it for so long because there have been so many new properties built and more to come on stream.”
YW says it is already addressing some of the issues with the council and others and will be funding a £275,000 hydraulic study of the town’s drainage and sewerage system to help identify “potential future” weakenesses. Flood Strategy Manager Wendy Kimpton said: “We welcome today’s report and fully endorse its findings that no drainage system could realistically have been expected to cope with the sheer volume of rain which fell over a very short period on August 3.
“The subsequent flooding had a traumatic impact on many people in the town and it’s incumbent on all the agencies involved to continue to work together to minimise the risk of flooding in the future.”
YW has recently completed a £1m programme of improvements at Carr Lane – a project already underway when last year’s flooding occurred.