Reducing storm overflows to improve local water quality
Wastewater improvement work is taking place in Falmouth to help reduce the use of storm overflows and protect water quality in the local area, including nearby beaches and rivers.
Investigations identified that parts of the sewer system can struggle during periods of heavy rainfall. This is influenced by factors such as surface water and groundwater entering the system, along with increasing demand. A phased programme of improvements is being delivered to address these challenges and strengthen the long‑term resilience of the wastewater network.
This scheme forms part of the wider £760 million Turning the Tide programme, which is delivering wastewater improvements across the region.
Project phase 1: Queen Mary Gardens - Complete
The first phase of the scheme focused on improvements at Queen Mary Gardens to reduce pressure on the sewer system during heavy rainfall by increasing the amount of wastewater that can be temporarily stored and treated.
A new underground stormwater storage tank has now been built beneath Gyllyngvase car park, with a capacity of 302,000 litres. The tank will capture excess flows in the sewer network during periods of heavy rainfall and safely store them until there is capacity at the local treatment works to be fully treated.
The completion of this phase marks an important step in improving water quality in the area, including Gyllyngvase Beach. The car park has now been reinstated following the completion of works in May 2026.
Project phase 2: Further improvements across Falmouth
The second phase of the Falmouth Sewer Improvement Scheme will build on the work at Queen Mary Gardens and deliver further improvements across the wider catchment.
From June, the next stage of design work is expected to begin. This will identify further improvements, which may include reducing groundwater entering the network, separating surface water from the sewer system, and providing additional storage where needed. More detail about these plans will be shared once the design work is complete.
Storm storage
Storm water is the number one cause of storm overflows. The huge rainfalls we're experiencing as climate change takes hold are overwhelming our sewers, meaning our storm tanks fill up faster and start overflowing before our pumps have chance to reduce the volume inside them.
We're hoping that our work to reduce infiltration will help reduce the amount of storm water entering our sewers.
But, we're also making sure there's enough storage to hold it all. That's why we're looking into building brand new storm storage near Queen Mary Gardens and investigating other potential areas.