Almost 40,000 birds have made their home on a nature reserve created using soil from tunnel excavations for the Elizabeth line.
Three million tonnes of earth were transported from London to Wallasea island in Essex and used to lift the ground level and make wetlands.
The RSPB bought the island in the mid-2000s and has been constructing the ideal conditions for wetland birds to feed, nest and refuel. The sea wall was removed in 2015 to make water flow on to the island for the first time in 400 years.
The charity then constructed islands, some of them from the Elizabeth line soil, and created lagoons and salt marshes. The wetland area now protects residents against flooding by absorbing storm waters.
Wallasea was once bereft of birds but now its visitors include 800 avocets, more than 10,000 knot waders, nearly 3,000 grey plovers and a similar number of bar-tailed godwits. It has reached a record of 39,000 birds overwintering on the site.
Rachael Fancy, the site manager, said: “When I first started working at Wallasea it looked an awful lot like a construction site – because that’s what it was. But just 10 years on, there’s no evidence of the diggers or trucks. There’s just thousands and thousands of birds who now use it as a refuge, shelter and nursery for their chicks. It’s an almost unbelievable transformation.”
Project managers said successful use of soil from the Elizabeth line showed that construction and nature restoration could go hand in hand.
Milo Sumner, coastal programmes manager at RSPB England, said: “Wallasea shows what’s possible when business has an ethos of working with, and alongside, nature. The creation of the Elizabeth line was one of the most ambitious infrastructure projects in decades, and by collaborating we were able to create a win for nature and people from what would otherwise have been a huge pile of wasted soil.
“We’d like to say a huge thank you to Transport for London for jumping on this opportunity, and of course to our teams and volunteers who helped make it a reality.”
