Thames Tideway Tunnel: CSO Diversions

Mariners are advised that constructors for the Thames Tideway Tunnel are in the process of connecting the tunnel to new combined sewers at seven sites on the Thames. 

At this stage in the process the new combined sewers are connected to the Tunnel but the tunnel is operating to half its capacity. This means that any rainwater and raw sewage which would normally be collected by the Tunnel and transferred to a treatment plant at Beckton may instead discharge directly into the river at these sites if the half tunnel becomes overwhelmed or is not available. 

This half tunnel testing period is expected this period to be in effect until later in 2025. 

The seven sites and their associated Notice to Mariners are:

If no Notice to Mariners number is associated with a site this means that it has not yet been connected to the warning system. This Port Wide Notice will be updated regularly as new CSO sites are diverted. 

CSO discharge alerts and warnings will be broadcast by London VTS on Ch 14. Additionally, the live status of each CSO is available at www.pla.co.uk/cso-status

Mariners should pay attention to warning lights and exercise caution when navigating in the vicinity of these sites.