A stunning timelapse video has revealed how a huge concrete roof was installed on one of Severn Trent’s biggest storm overflow tanks.

The fascinating film shows separate lid sections going on top of the 25m deep by 25m wide mega-tank in Stroud, Gloucestershire, which will protect residents from flooding and boost river health. The roof installation took weeks to complete  but the video lasts just 85 seconds, which you can watch by clicking here  

The overflow tank has the capacity of 7,400m3, the equivalent of three Olympic sized swimming pools or over 24,500 bathtubs of water.

Now residents can hear more about the incredible feat of engineering - part of Severn Trent’s £25 million project to upgrade the town’s Victorian-built sewer network – at a community drop-in event. It is being held on Monday 30^th September at Cotswolds Bowls Club, based in Golden Jubilee Way, Stroud, GL5 3HQ, between 5.30pm and 7pm.

Severn Trent project manager Chloe Dobbs will be on hand to answer questions, along with representatives from our partners Galliford Try, who filmed the timelapse video.  

Chloe, 24, said: “I’m really looking forward to meeting residents and bringing them up to date on the project, including the huge new storm overflow tank.”

The massive tank, sited near the Ebley Bypass, will drastically improve water storage capacity in the area by around 1,300% during heavy rainfall, helping to reduce sewer flooding and spills into rivers and watercourses.  

It will have innovative smart controls that can hold storm water back during severe weather events and return it back to our treatment works when rainfall has subsided.

The Stroud scheme also includes installing four miles of new enlarged pipes, as well as separating surface water from the waste network.

Chloe added: “Customers and the environment have been central to this project. By creating so much extra storage, we are going to prevent future flooding for residents and businesses - and of course reduce potential overflow spills into waterways.”

The completion of the tank roof means a 30mph limit on the bypass has now been removed.  

The next phase of the project is to carry out upgrades to Severn Trent’s Stanley Downton Treatment Works by next May, to ensure that the new storm overflow works efficiently. A new project completion date has been set at September 2025, following some unforeseen equipment delays.  

Chloe added: “We’re working as quickly as possible to complete the project and would like to thank all the residents of Stroud for their ongoing patience.

“I’m really looking forward to meeting local people and answering any questions they may have on 30^th September.

“Customers and the environment have been central to this project. By creating so much extra storage, we are going to prevent future flooding for residents and businesses - and of course reduce potential overflow spills into waterways.”

Peter Richardson, Senior Project Manager, Galliford Try, said: “We are delighted to have been working with Severn Trent to deliver this innovative scheme that will bring so much benefit to the community, contributing to a reliable sewer network, protecting homes and businesses from blockages and flooding, and improving river health.”