Smart sewer gates and pipe upgrades to reduce storm overflows in Cowes
Upgrades to infrastructure paired with innovative new technology and automated intelligence dramatically reduced storm overflows from Terminus Road in Cowes, Isle of Wight. Here's how...
The problem at Terminus Road
At Terminus Road, wastewater from North Cowes joins up with wastewater from Cowes High Street before being pumped away for treatment. In this system, there is a storm overflow to protect low-lying areas of Cowes from flooding.
When the storm overflow was activating more often than it should, we 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
We 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.
We 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.
Note: the outfall pipe associated with the Terminus Road storm overflow is also connected to a different storm overflow in Cowes, so there may still be releases from the outfall despite the Terminus Road overflow not activating anymore. We will of course address releases from other storm overflows as part of our Clean Rivers and Seas Plan.
What's next?
Work is underway to install roadside sustainable drainage systems in Gurnard to manage surface water run-off from roads. This will help reduce localised flooding and ease the strain on the sewer system when it rains.
Look at our Clean Rivers and Seas Plan to see all our planned storm overflow investments on an easy-to-use interactive map.