Flood Alleviation Scheme

Protecting people and planes…

As a result of climate change, Crawley has seen increased flooding occur throughout the town over the years. In 2000, when the last significant flood occurred, 109 properties were flooded and the A23 under Gatwick Airport’s South Terminal was closed for three days causing major disruption to the whole region.

Following the flooding in 2000, the Upper Mole Flood Alleviation Scheme was developed by the Environment Agency to adapt to future changes in climate and provide an improved level of flood protection for thousands of people living in Crawley, South West Horley as well as Gatwick Airport.

The project involves creating new, or improving existing reservoirs to store large amounts of water during spells of heavy rainfall. The stored water will slowly be released back into the river, which will help reduce the risk of high flows that would have otherwise caused flooding to nearby properties.

The proposed storage reservoir sites are Tilgate Lake in Tilgate Park, on the Gatwick Stream at Worth Farm, the Stanford Brook at Clay’s Lake Pease Pottage and the River Mole in Ifield.

The first project in this multi-million pound scheme is planned to take place at Tilgate Lake. The proposed plan is to raise the height of the existing dam by 2.5 metres (8.2 ft). Whilst this will cause temporary disruption to the lake’s users, it will protect thousands of people’s homes from the risk of flooding in the future.

Please visit our dedicated Tilgate Dam Improvement Scheme page, to find out more about the specific plans for the project.

Adapting to Climate Change

The climate in the South East is changing which will increase the frequency and intensity of extreme weather such as flooding and droughts.

Crawley Borough Council is committed to making sure that our wildlife, infrastructure, communities and individuals are able to cope with these unavoidable changes by putting measures in place such as the ‘Upper Mole Flood Alleviation Scheme’ to help prevent future problems caused by an increase in rainfall.

To find out more about what the council are doing to adapt to and combat climate change please visit the Adapting to Climate Change page.

For further information and advice on flooding, please view the Flooding page.

Contact Details

If you have any further questions about the Upper Mole Flood Alleviation Scheme or the Tilgate Dam project, please contact Sophie Lee at the Environment Agency on sophie.lee@environment-agency.gov.uk