Wildlife habitat created from super-sewer spoil

Little ringed plovers are among birds spotted at the Rainham site. Image: Sonika Agarwal, Unsplash

Spoil excavated from London’s 25km super sewer project is being used to create a wildlife habitat inside the M25 motorway, which circles the UK capital.

Nearly 1.5m tonnes of clay and chalk from the Thames Tideway Tunnel project is transforming the 100-hectare site in Rainham, Essex. Clay excavated and transported by barge from west London is creating an impermeable layer to retain water in new lakes, while the chalk excavated from the east of London is being used to create a varied landscape.

The plot on the northern bank of the Thames is owned by the Royal Society for the Protection of Birds (RSPB) and managed by the Port of London Authority and its contractor Land & Water. It sits close to two existing RSPB sites – Rainham Marshes and Wennington Marshes Nature Reserve - and is already home to a number of bird species, including lapwing, little ringed plover and red shank.

Clay and chalk are being used to create the 100-hectare wildlife habitat. Image: Tideway

“To see this site being restored in this way, using material dug out from deep beneath London, is just fantastic."

Alan Johnson, RSPB

Alan Johnson, RSPB’s area manager for Kent and Essex, said, “To see this site being restored in this way, using material dug out from deep beneath London, is just fantastic. Many bird species are returning and we fully expect the wildlife here to flourish as the site develops over the coming years.”

Historically, the site has been used as a dredging disposal facility but in recent times, there has been a desire from the RSPB and Natural England to restore it to a wetland for wildlife.

Tideway is delivering a major upgrade of London’s sewer system to cope with the city's growing population. Due to complete in 2025, the 7.2m-diameter, 25km tunnel will intercept, store and ultimately transfer sewage waste away from the River Thames.

In its early planning phase, Tideway had committed to beneficially reuse 85% of its excavated spoil and for 90% of this material to be transported by river – and Rainham was seen as an ideal site.

Samantha Freelove, Tideway legacy and sustainability manager, said, “As we work to protect the River Thames from sewage pollution, we want to be an environmental project not just in what we’re doing but in how we’re doing it. That’s why our collaboration with the RSPB and Land & Water, to ensure the spoil we’re excavating is being reused in the best way possible, has been so important.”

The Tideway Tunnel will intercept, store and transfer sewage away from the Thames. Image: Tideway