Flash flooding in Preston last week proved that the technical issues faced during construction of the city’s new sewer tunnels were a thing of the past with the new tunnels coping well under the demand.
Autumn 2012 saw the completion of the twin state of the art pipe-jacked tunnels – the first of their type in the UK – after facing major leaks in excavation and emergency evacuations since work started four years earlier.
Since the 3.5km long underground tunnel, capable of holding 40 million litres of storm water, was switched on engineers from United Utilities have not had a chance to see it fully tested until this week.
During the height of the storm the tunnel was pumping 1,500 litres of storm water a second to Preston Wastewater Treatment Works and John Oldham, Network Manager from United Utilities admits that 15mm of rain in just 15 minutes did mean that “some areas witnessed flooding”, as the highway and residential roads struggled to deal with the volume of rain.
Bearing in mind the challenges encountered – such as tackling three sewer emergencies in 13 months – by the engineers from KMI water, a joint venture comprising Kier Construction, J Murphy & Sons and Interserve Project Services, which worked for United Utilities, the news that the completed project is clearly fit for purpose must be very welcome.