Work is progressing well on Southern Water’s multi-million pound scheme to radically change the Victorian sewer system in Portsmouth.
Working at various locations in the city, this £20 million scheme, which started in the autumn, will reduce the risk of properties in Portsmouth and Southsea being flooded by overflowing sewers.
Work is now complete at Kirtley Close, in the north of the city, and repairs to prevent tidal infiltration to the sewer network at Spice Island, where we have been using techniques which require less digging to minimise disruption, are well underway.
The next stop will be Shamshaw Park where the project team will be updating a pumping station, closely followed by Tangier Road where a pipe is being laid to take rainwater to a new outfall in the Great Saltern Lake.
Since Victorian times, the sewers in the city have carried both wastewater and rainwater in a combined system. Once complete, this project will see large amounts of rainwater – up to 6,000 litres per second during storms – diverted away from the existing combined sewers and into new sewers that discharge this rainfall into the sea.
This will ease pressure on the sewer system and also reduce the amount of water flowing to Eastney Pumping Station during heavy rain, reducing the risk of flooding.
Southern Water’s Project Manager Jon Kenrick said: “This is a major investment for the whole city and the benefits should be seen long into the future. We have been liaising closely with the local communities in which we are working and would like to thank everyone for their patience so far.”
Eastney Pumping Station is also seeing improvements with the addition of an innovative “real time” monitoring system to give early warning of severe weather along with the refurbishment of the site’s control system, pumps and screens.
A further £10 million scheme is being planned for the outfall at Fort Cumberland, which in times of heavy rain releases water into the Solent to prevent flooding.
The engineering solution is complex but work due to start this spring will deliver changes to the way stormwater is handled at the station. Further investment is also being planned to repair and upgrade the screens which remove debris from the stormwater. These screens were severely damaged during a storm in 2010 and require major refurbishment as a result.
In the long-term, Southern Water is looking to make more improvements to Portsmouth’s wastewater system to further reduce the risk of flooding.