Upgrades to infrastructure by Southern Water paired with innovative new technology and automated intelligence have dramatically reduced storm overflows from Terminus Road in Cowes, Isle of Wight.

At Terminus Road, wastewater from North Cowes joins up with wastewater from Cowes High Street before being pumped away for treatment. This system includes a storm overflow to protect low-lying areas of Cowes from flooding.

When the storm overflow was activating more often than it should, the water company investigated and discovered that a sharp bend in the pipework underneath Terminus Road was causing water to back up into the sewer system. This would cause the sewer to fill to capacity and then trigger storm overflows to get rid of the excess water.

Traditional engineering and modern AI technology

Photo: New and improved pipework and the smart sewer gate installed at Terminus Road

Southern Water removed the existing pipework that was causing the backlog and rebuilt it to remove the tight bend, allowing water flow to pass through with ease.

The utility also installed a Centaur smart sewer gate controlled by downstream sensors placed in flood risk areas. If the sensors predict a flood risk, the Centaur gate will operate to prevent flooding.

Reducing storm overflows

Storm overflow releases from the Terminus Road overflow immediately decreased once the pipework had been adapted, and stopped completely following the installation of the smart sewer gate in November.

Since completion, there have been no storm overflow releases from the Terminus Road overflow, despite incredibly heavy and frequent rainfall. Roughly 135 storm overflow releases were prevented in 2024 and releases have decreased by 94% overall.

A graph showing how many storm overflow releases were predicted through 2023 and early 2024, vs how many actually happened, showing a dramatic reduction.