Completed in 2022, the Newhaven Flood Alleviation Scheme was designed and built in response to the devastating 2013 floods which impacted the south coast of England. With hurricane-force winds and the greatest storm surge in 60 years, over 60 properties were flooded as well as local businesses and major national infrastructure including the A26 and the Lewes to Seaford rail line. Arcadis worked in collaboration with our client the Environment Agency, to design a scheme to reduce flood risk from the sea to 430 homes and 390 businesses.
Arcadis working with our Construction Partner Jackson Civil Engineering, designed and built over 4km of flood defences to provide up to a 1-in-200-year standard of protection, taking into account the effects of climate change. In addition to homes and businesses, the scheme also reduces the risk of flooding to local infrastructure including the A26, the rail line and Newhaven train station, as well as the Local Port.
The scheme incorporates a variety of flood defences including clay embankments, demountable barriers (stop logs), reinforced concrete flood walls, low-level grass bunds and temporary barriers. The temporary defences run along the A26 and across the rail line, providing the first flood defence to cross a working rail line in the UK. We worked in partnership with Network Rail team to ensure its successful design and delivery.
Other unique aspects to this scheme include:
- the use of cement-free concrete for sections of the defence, offering our client the potential to reduce their embedded CO2 by up to 88%.
- Seeding defence embankments with wildflowers to enhance biodiversity.
- The use of chalk within the embankment shoulders, saving the client approximately £240,000.
In addition to flood protection, the scheme supports the wider regeneration of Newhaven and will help bring new investment, jobs and homes to the area. The scheme, forecast to cost £18 million, was delivered under budget and with a limited time extension, despite the impact of Covid-19 restrictions.