Lower Thames Flood Risk Management Strategy

The Lower Thames Flood Risk Management Strategy is a long-term plan to manage flood risk in the Lower Thames area. The Environment Agency produced the plan with other public bodies.

The strategy aims to reduce the risk of river flooding to 15,000 properties with a one per cent annual (1 in 100 year) chance of flooding, from Datchet to Teddington.

We will carry out the Lower Thames Strategy in two phases. Phase 1 includes:

  • ecological surveys of the River Thames;
  • individual property protection measures;
  • capacity increases to Sunbury, Molesey and Teddington weirs;
  • widening and deepening the Desborough Cut;
  • developing outline planning proposals for the engineering channel.

Phase 2 includes:

  • the detailed engineering design;
  • securing detailed planning permission;
  • building three flood diversion channels.

The Lower Thames Strategy also includes improving mapping information for emergency evacuation plans.

Progress on individual property-protection measures

Individual property protection measures include flood barriersIndividual property protection measures include door barriers, non-return valves, sump pumps and airbrick covers. 

This part of the project will provide individual flood protection to those properties that will not be fully protected by the planned engineering work. This is estimated to apply to some 1,600 properties across the Lower Thames area and the work is planned to take place over the next three years.

Residents living in properties identified as eligible for the scheme have been sent details of how to register for a threshold survey. We would like to thank all residents who took part in our doorstep survey in January.

Between December 2012 and February 2013, we held drop-in events for residents in the boroughs of Richmond, Windsor and Maidenhead, Runnymede, Spelthorne and Elmbridge so they could find out more about the scheme, and register for the individual property-protection measures project.

Registration for threshold surveys closed on 4 March and surveys were done between 4 and 8 March 2013. These surveys, and the property questionnaire, will help to confirm the property’s flood risk and its suitability for property-level flood protection. We will be writing to residents in April 2013 to inform them of the outcome.

In April and May 2013 we will be appointing suitable companies to do the work. In May and June we will analyse the results and recommend a package of flood-protection measures for each property. Installation is expected to begin during late spring or early summer.

Property protection measures are being installed in Chaseside Gardens, Rosemead and Bridge Road in Chertsey. Around 30 properties were surveyed and installation began in November 2012.

We installed individual property-protection measures at 57 properties in Spelthorne and Elmbridge and 40 in Runnymede, as part of a pilot study in 2012. Since then we have held exercises to test how well residents who have had these measures installed were able to activate them following a flood warning. 

Other work in progress

  • In April 2012, we began our three-year programme of ecological baseline surveys. These are essential for us to understand the local environment. So far we have done bird surveys and water-level surveys.
  • We are carrying out studies to improve the capacity of Sunbury, Molesey and Teddington weirs.
  • We have involved local residents throughout the development of the Lower Thames Strategy, through public exhibitions.
  • We are continuing to work with local authorities, other professional partners and communities as the strategy develops.

Timescales and funding

We expect the Lower Thames Strategy project to last 15-20 years. This is dependent on funding.

Following changes to the way flood defence funding is allocated, we currently have a significant shortfall for carrying out all of the Lower Thames Strategy. We are progressing Phase 1 with support from the local levy, and we are working with partners to bridge the funding gap by identifying various sources of contributions.

Working in partnership is key to the success of the Lower Thames Strategy, and we will continue to explore all avenues of funding to complete the project.

Further reading

Contact us

If you have any questions about the Lower Thames Strategy, please contact us:


This page was updated on 15 March 2013.