Truro flood defence completion of a new tidal barrier

The completion of the work secures the city’s protection against rising flood risks for the next three decades.

The Environment Agency confirmed that newly installed flood defence gates are now fully operational, safeguarding 185 commercial and residential properties in the city centre.

The gates form the heart of Truro’s flood risk management system, working in tandem with the Idless and New Mills Dams to mitigate threats from tidal surges and river flooding.

The ambitious engineering project began in April 2024, replacing ageing infrastructure that had reached the end of its serviceable life. Installation of the new gates was completed in August 2024 using a 400-tonne crane during spring tides to ensure optimal conditions. Final completion of the barrier work is expected by the end of October 2025.

During construction, contingency plans were tested when tidal surges exceeded forecasts. Temporary stoplogs were deployed for the first time at the site, successfully preventing flooding and validating the Environment Agency’s emergency planning.

“This project represents a significant investment in Truro’s flood resilience,” said Andrew Houghton, Operations Manager at the Environment Agency. “The barrier and its controls are more reliable, meaning we can ensure effective flood risk management for the community into the future.”

Philip Ramsay, Operations Director for Kier Natural Resources, Nuclear & Networks, added: “We’ve applied innovative techniques and experience from other sectors to make these gates more efficient and reliable.”

Beyond flood protection, the project has delivered unexpected community benefits. The old barrier control room, no longer needed due to upgraded specifications, has been repurposed as a pavilion at Perranporth Cricket Club.

The prefabricated building now provides additional changing facilities, supporting the growth of female cricket at the club.

Meanwhile, upgrades to the Idless Flood Storage Reservoir on the River Allen are nearing completion and expected to be operational by December.

These improvements will enhance the dam’s resilience during severe weather, ensuring continued protection during extreme conditions.

At New Mills Dam, Environment Agency teams successfully conducted a major emergency exercise in July, demonstrating their ability to rapidly reduce water levels using high-volume pumps.

A follow-up desktop exercise in September completed comprehensive training and reinforced best practice procedures for reservoir safety nationwide.

Together, the tidal barrier, Idless reservoir upgrades, and New Mills Dam preparedness form a multi-layered defence system designed to protect Truro from increasingly frequent and intense flooding linked to climate change.

The announcement coincides with Flood Action Week, the Environment Agency’s annual campaign urging residents to check their flood risk and prepare accordingly. With the Met Office forecasting a wetter-than-average autumn, the agency warns that communities must remain vigilant despite ongoing drought conditions in some areas.

Residents are encouraged to visit Gov.uk/prepare-for-flooding to assess their flood risk, sign up for warnings, and explore property-level resilience measures.