Policy paper

Updated hydraulic model is now available

An updated 1 dimensional (1D) hydraulic model is now available for the Lower Thames catchment.



An updated 1D hydraulic model for the Lower Thames catchment is now available for use on the River Thames Scheme. The model is being used to:

  • produce an updated economic (benefits) assessment (used for the Strategic Outline Business Case)
  • propose capacity improvements to each of the weir structures at Sunbury, Molesey and Teddington
  • develop a hydraulic concept design for the River Thames Flood Channel to optimise the channel capacity and map reductions in flooding that the scheme will create

We are building on this 1D model to create a 1D/2D model. This is the largest and most complex hydraulic model produced by the Environment Agency to date, and the largest in Europe. The 1D/2D model will add an additional level of accuracy over the 1D, as it will enable us to better understand direction of flood water flow and water velocities. The 2D model will be used to address the following areas for the River Thames Scheme:

  • better understand the behaviour of water within the flood plain
  • inform the location of bunds (which help direct the water into the flood alleviation channel)
  • model the interface with the River Thames tributaries
  • review which areas may benefit from community measures or property level products

The 1D/2D model will improve our understanding of flood risk and will update our catchment modelling from Hambledon Lock to Teddington Lock on the lower River Thames. This will be used to update our flood risk products available to our partners and the public.

Find more detail on the River Thames Scheme.

Published 15 July 2016