The brief
We assisted our client with the delivery of a 19ha online flood storage area to the Gatwick Stream tributary.
This scheme will allow for a one in 100 year level of protection and will help to prevent the flooding of Gatwick Airport and the A23. We were commissioned to undertake the soft landscaping, invasive species management and ecology elements of the works.
What we did
- Mechanically cut and hand pulled up to 0.82ha of Himalayan balsam along the existing Gatwick Stream, and implemented a subsequent spraying regime
- Ripped 12.5ha of compacted soil to shatter the clay pan and facilitate seeding
- Hydro-seeded the same area with a wildflower meadow grass mix suitable for clay
- Planted 10,700 native bare-root transplants
- Planted 680 8-10cm native bare-root specimen trees
- Supplied and planted native riparian plants along parts of the newly constructed scheme
- Undertook an electric fishing exercise in two phases to assist with in-channel works.
The works that we undertook on the Gatwick FAS were not without their challenges, including flooding of the site by the next-door sewage treatment works, very difficult ground conditions, and tight timescales. The works were completed successfully and the trees and grassland have since flourished. The site looks great.
Thomson project manager, Gatwick Airport flood alleviation scheme
