Runnymede’s Environmental Characteristics

Water and Flood Risk

Watercourses and lakes are a key characteristic of the Borough, with the River Thames running along the Borough’s eastern boundary, and the Basingstoke Canal forming the south-eastern boundary. The River Wey, Addlestone Bourne and Chertsey Bourne run through the Addlestone and Chertsey areas of the Borough, so much of the eastern side of the Borough is subject to fluvial flood risk. The River Thames and its tributaries are the primary sources of flood risk in the Borough, but other sources include the Hurst Ditch, Meadlake Ditch and the Moat (tributaries of the Chertsey Bourne system).

Recent trends in the ecological status of waterbodies within Runnymede are, in the main, either moderate or poor, with the condition of several declining over time. There are various reasons for this, including sewage discharge, agriculture, recreation, and poor nutrient management.

Two groundwater units – the Chobham Bagshot Beds (good overall status) and Lower Thames Gravel (poor overall status) units also lie within Runnymede. Groundwater Source Protection Zones have been designated to protect water supplies from pollution.

The Environment Agency identifies Runnymede as an area of serious water stress, with projections that water demand will outstrip supply in the regional by 2080.

Water & Flood Risk Headlines

Within Runnymede, there are:

  • 8 Main Rivers
  • 1 Canal
  • 3 Groundwater Source Protection Zones
  • 12,418 residential properties and 1,267 commercial properties in Flood Zone 2
  • 8,620 residential properties and 668 commercial properties in Flood Zone 3
  • More than 20% of properties situated in Flood Zone 3
  • 0 formal flood defences, but 1 proposed (River Thames Scheme)

Flood Zone 1 is not shown in the map, but covers all areas not contained within Flood Zones 2 and 3.

What does this mean for the Local Plan?

The new Local Plan, as far as it is able to do so, and without repeating national decision-making policies (NDMPs), should retain, strengthen and/or implement policies/actions relating to sustainable use of water/water efficiency (potentially including commercial development) as well as protecting and aiding opportunities to improve water quality. 
 
The Local Plan should also seek to minimise the risks from and to development by avoiding inappropriate development in areas of flood risk (with sustainable drainage required through NDMPs). Protection and enhancement of blue infrastructure assets/connections should also be included including flood protection measures where possible. The new Local Plan should continue to ensure that the sequential approach to flood risk is adopted, and to support the delivery of the River Thames Scheme. 

Sources of further baseline information:

Detailed baseline information, an analysis of existing conditions and future trends, and how this information will inform the new Local Plan, can be found in Chapter 6 of the SA Scoping Report available on the new Local Plan evidence base web page:

Sources of other useful information: