Falmouth Stormwater Overflow Improvement Scheme
We're working fast to reduce spills in Falmouth
Falmouth's beach at Gyllyngvase has enjoyed Good bathing water for many years now.
But we know that sometimes the sewer system is struggling to cope. Our investigations tell us that this is for a number of reasons including population growth in the area, groundwater entering the sewers, and the age of some of our assets.
We're on a mission to reduce the impact the town's sewerage system is having on the environment, including in the estuary waters.
Queen Mary Gardens Programme
The Queen Mary Gardens Programme forms a key part of South West Water’s wider Falmouth Stormwater Overflow Improvement Scheme. This initiative aims to reduce the environmental impact of storm overflows in Falmouth by tackling infiltration, increasing stormwater storage, separating surface and foul water flows, and upgrading treatment capacity.
This scheme is part of South West Water’s ambitious Turning the Tide programme that will invest record amounts to target storm overflows throughout the region.
Project details
We’re building a new stormwater tank in Queen Mary Gardens that will hold 302,000 litres of water. This will mean more wastewater can be stored at times of heavy rainfall then treated, reducing our reliance on storm overflows in Falmouth.
The tank will be installed via the Queen Mary Gardens/Gyllyngvase car park, with all flows screened before entering. These screens are also being upgraded.
Programme of works
| Date | Activity |
|---|---|
| Monday 6 October | Start on site |
| April 2026 | Planned completion and reinstatement |
1. Surface water separation
Combined sewers take both foul sewage from homes and businesses, as well as surface water from roads, to the treatment works.
Being rainwater, surface water doesn't need much treatment before being released back into rivers. Sending it to the treatment works not only wastes energy and money in transporting and treating it, but also risks overloading our pump stations and storm tanks.
By seperating sewers (building one to hold the foul flows and one to hold surface water) we can reduce the flows inside our sewers and reduce the risk of storm overflows. The surface water is released into rivers after going through an oil interceptor.
2. Infiltration
Infiltration is when surface water or groundwater enters our sewers in places it's not meant to (e.g. through manhole covers).
This means that a lot more wastewater enters the sewers and increases the risk of activating our storm overflows.
To stop infiltration we'll be lining, repairing and replacing our pipes and manhole covers in hotspot areas. We call this rehabilitation work.
3. 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 The Moor, and we're investigating other potential areas.
4. Our treatment works
By upgrading our treatment works we can reduce the amount of time wastewater stays in our system. We're looking into ways to increase the volume of wastewater that can be treated at any time. A solution will be designed based on the results of our investigations.