Millions of tonnes of earth from the construction of new rail tunnels are being used to help create a huge wetland nature reserve which will be the largest in Europe.
The scheme to create coastal habitat twice the size of the City of London on Wallasea Island, Essex, using 4.5 million tonnes of earth excavated for London's Crossrail project, will be launched by new Environment Secretary Owen Paterson.
The project by the RSPB aims to turn low-lying farmland into 670 hectares (1,650 acres) of wetland habitat for tens of thousands of migratory birds and other wildlife such as otters, herring and saltwater plants, as well as providing around eight miles of coastal walks and cycle routes.
The earth, which will arrive by ship from Crossrail's tunnels in London, will be used to create higher and lower areas of ground on the island to restore the original wetland landscape of mudflats, saltmarshes and lagoons.
Crossrail has constructed a new jetty and facility to handle the material at Wallasea Island, and more than 2,000 ship-loads of excavated earth will be delivered, with up to 10,000 tonnes unloaded per day at the operation's peak.
The RSPB, which bought the land for the large scale conservation project, warns that there has been dramatic loss of coastal habitat in the past 400 years and without schemes such as Wallasea, rising sea levels could lead to the loss of another 1,000 hectares (2,500 acres) in the next decade.
The Government has a target to recreate 3,600 hectares (8,900 acres) of saltmarshes and mudflat habitat by 2015