Project Overview

Below you will find a brief overview of the works that will take place at Tilgate Lake to improve the dam.

If you would like to view detailed maps and diagrams please download the Environment Agency’s Improving Tilgate Dam document.

Tilgate Dam

The plan is to increase the amount of water that can be stored at the lake, when there is a flood risk, by raising the height of the existing dam by 2.5 metres (8.2ft). Dam works will not affect the lake’s normal water level. Raising the dam will allow extra water to be stored when flows are high, such as during a heavy downpour of rain, which will enable the water to be released back into the river in a controlled way, helping to reduce the risk of high flows that would have otherwise caused flooding to nearby properties.

Material for the Dam

The Environment Agency is proposing to use earth from Tilgate Park to build part of the new dam. This will mean digging a hole (borrow area) to the east of the lake. Using soil from the same site means that it does not have to be brought in from elsewhere, which reduces the number of lorries needed to access the site. Once a sufficient amount of soil has been removed from the site, a new reed bed habitat will be planted in its place and the area will be cleared of vegetation to improve the views of the lake.

Timings

Winter 2009/2010

Planning permission was approved and removal of trees took place to provide access to the dam and borrow area.

Spring 2010

The lake to be lowered to enable fish removal (for the latest information on fish removal, please download this statement or call the Environment Agency, details below). As a result it will be fenced off to ensure the safety of adjacent users. The existing footpath on the western side will remain open along with the dam crest and fisherman’s car park. The path on the eastern side will be redirected through the woodland. The fish will be removed from the lake.

Summer/Autumn/Winter 2010

Works to enhance the dam crest will commence towards the end of May 2010. The Lake and Fisherman’s car park will be closed.

Spring 2011

Works scheduled to be completed.

What are the positive and negative impacts of this project?

Positive Impacts

• Reduced flooding: This project will impact on thousands of lives in Crawley by reducing the risk of flooding to people’s homes as part of the Upper Mole Flood Alleviation Scheme.

• Create new wildlife habitats at Tilgate Park: New reed bed and deadwood habitats as well as new tree planting will improve the environments for wildlife such as grass snakes, bats and slow worms.

• Create an attractive recreation area: New picnic and seating areas around the dam will be created.

• Better views of the lake: Existing bank side trees and rhododendron near the borrow area to the east of the lake will be cleared to ensure better views.

• Increase the safety of the dam: The existing structure of the dam will be reinforced and then increased by 2.5 metres. This will ensure that during spells of heavy rainfall the dam will be secure enough to hold an increased volume of water.

• Better disabled access: There will be full disabled access on both the old and new paths on the top of the dam.

Negative Impacts

Temporary Disruptions

To ensure the safety of those working on the dam, the lake’s water height will have to be lowered. This will have several impacts on the lake’s users:

• The lake will be completely out of use during the construction period (likely to be around one year).
• The footpaths surrounding the lake will be closed to walkers/runners.
• The Fisherman’s car park will also be closed. Please note that the main car park will remain open.

Other impacts…

• Loss of some woodland and vegetation: Inevitably in a large scale project such as this one there will be some loss of woodland and vegetation. To offset this loss, new trees will be replanted and new wildlife habitats will also be created.

• Increased traffic movement: During the transportation of clay to Tilgate Park there will be increased traffic movement through the Tilgate area.

PLEASE NOTE: TILGATE PARK WILL STILL BE OPEN TO THE PUBLIC AS PER USUAL. ONLY THE LAKE ITSELF, THE PATHS AROUND THE LAKE AND THE FISHERMANS CAR PARK WILL BE CLOSED.

Funding of the Tilgate Dam project

The Upper Mole Flood Alleviation Scheme is approximately £15 million project funded by the Environment Agency, with Crawley Borough Council contributing around £100,000 towards the Tilgate Dam project. The Council is also committed to maintaining the area around the dam after the works are completed.

Each time there is major flooding the resulting damage and costs are in excess of several hundred thousand pounds. Therefore by going ahead with this project it will save thousands of taxpayer’s money in the long run.

Contact Details

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