The Thames Tideway Tunnel will broadly follow the River Thames
Our tidal physical model of the Thames
London’s Victorian sewerage system is a combined system designed to deal with both rain water runoff from streets and buildings and foul water from homes and businesses. Part of the combined system design allows the system to overflow into the tidal River Thames to reduce the risk of back up into streets and houses. CSO discharges have a detrimental effect on water quality in the river and increase risks to users of the river. Control of CSOs are required to meet European environmental guidance outlined in the Urban Waste Water Treatment Directive (UWWTD).
To address the problem Thames Water plans to tackle the problem through a three stage programme of treatment works improvements and construction of two transfer and storage tunnels: the Lee Tunnel and the Thames Tideway Tunnel. The Thames Tideway Tunnel is the last of the projects and consists of a 15.5 mile long tunnel, up to 70 m deep and 7.2 m/6.5 m diameter main tunnel. The tunnel will broadly follow the path of the River Thames through London. Once a flow event is intercepted and redirected into the tunnel it will be transferred for treatment at Beckton STW.
The multi billion project will involve major construction work at a number of sites on the foreshore of the tidal River Thames. Engineering works in the river are challenging and have the potential to change flow patterns, sediment movement and the morphological regime in the vicinity to foreshore sites. Since starting work on the project in 2009, HR Wallingford has helped the project design team understand the impact the proposed works will have on the river. We have carried out a comprehensive programme of fluvial computer modelling and selected physical modelling to evaluate these impacts. Results have been used to inform the development of the design of both temporary and permanent works, allowing development of a design that minimises the impact on the river environment. HR Wallingford’s findings have also provided a significant contribution to support the Environmental Statement presented within the Application for Design Consent.
HR Wallingford’s contribution to the project has included:
A comprehensive programme of fluvial modelling and assessment has been completed to evaluate the potential effects of the temporary and permanent works associated with the Thames Tideway Tunnel.