The next phase of Southern Water’s sewer sealing programme to tackle decades of groundwater-related flooding in the Lavant Valley is set to begin in West Dean.

The scheme is designed to prevent groundwater forcing its way into local sewers, as this can overload pipes, pumping stations and treatment works, causing storm overflows and flooding. This West Sussex scheme will then in turn improve water quality in the River Lavant – a unique chalk stream which feeds Chichester Harbour.

So far, Southern Water teams have sealed 15km of sewers in the Lavant Valley, using specialist plastic linings to seal ageing pipe joints and prevent infiltration through the chalk aquifer.

Now, attention is turning to a further 5km of sewer in West Dean, as the project continues to move down the valley. The water company has also made upgrades to its nearby treatment works at Lavant where there is a manmade wetlands which helps to naturally filter flows.

Southern Water programme delivery lead Andy Morris said:

“The chalk ground in the Lavant Valley acts like a sponge, soaking up rainfall for months at a time. When this groundwater enters our sewer network, it can overload the system and lead to sewer flooding and storm overflows.

“By sealing these ageing pipes, we’re not only protecting homes and businesses — we’re also helping to improve the health of the River Lavant, which is a valuable chalk stream.

“Reducing groundwater infiltration means fewer storm overflows, which in turn supports better water quality downstream in Chichester Harbour. This work is already making a real difference for local communities and the environment, and moving into West Dean is another important step forward.”