Trant IOW Support Southern Water with Successful Pilot Scheme Tackling Sewage Spills


May 03, 2023

A new pilot scheme undertaken by Southern Water on the Isle of Wight has seen the installation of 200-litre water butts to a number of households and facilities in the village of Havenstreet. The water butts capture and slow the return of rainwater into the water systems, reducing pressure on storm overflows and helping to reduce spills by 70 per cent.

The project is part of a £5 million investment into a number of nature-based engineering solutions for sustainable drainage schemes (SuDS) to help deal with rainwater run-off from hard surfaces. The main area of focus is to slow the flow of rainwater entering the water network during heavy rainfall events.

The concept was initially trialled at one large nursing home where up to five tonnes of water was coming off the 800m² roof when it rained and overwhelming the CSO. Trant Engineering commissioned bespoke planters in keeping with the old Victorian building which are able to absorb a significant amount of rainwater.

“Slow drain” butts were offered to residents in the village of Havenstreet and on one street, with 72 per cent of households using them, the nearby CSO (which previously activated 27 times a year when rainfall exceeded 5mm) saw only one spill during the six-month trial. Southern Water expects the butts to keep annual incidents down to single figures.

The installation of water butts allows rainwater to be captured, and a drain halfway up the receptacle slowly releases the water back into the network over a five-hour period which prevents nearby combined sewage overflows (CSOs) from being overwhelmed.

The Havenstreet trial was so successful that the Department for Education requested that planters and water butts be installed at twelve primary schools and five academies across the IOW.

“The timescale for SuDS for the schools has been so tight but Ian Deakin and a team from Trant have risen to every challenge and pulled it out of the bag. I’m so grateful for the team, who have gone above and beyond to support us in making things happen” says Laura Moran, Project Manager of Southern Water’s Clean Rivers and Seas Taskforce.

Following the success of the scheme, Southern Water plans to carry out similar trials in Kent, Hampshire and East Sussex.