BAM Nuttall is delivering a vast site cleanup in the heart of one of London’s biggest regeneration zones. James Kenny explains.
Clearing any site can be difficult, but when it is located in the middle of one of the largest regeneration areas in London this brings its own unique challenges.
BAM Nuttall has the remediation contract for the former South London Mail Centre in Nine Elms. Awarded in May last year, BAM’s contract is to clean up the site ahead of its redevelopment.
This includes site clearance, demolition of the remaining post office facilities, removal of below-ground obstructions, remediation including onsite soil and water treatment, and bulk earthworks. Utility diversions to maintain supply to the Royal Mail delivery building are also in the contract.
“BAM has a strong track record on large urban remediation sites, from working at the Queen Elizabeth Olympic Park and also the King’s Cross Goods Yard sites, which has helped prepare us for the scenarios here,” says Dominic Scholey, agent for BAM Nuttall on the South London Mail Centre project.
The 6ha site had been used by Royal Mail since the 1970s, and prior to that was part of the Nine Elms gasworks, built in the latter part of the 19th century. Now valued at more than £600m, the site will be redeveloped with up to 1,870 high-rise homes, a primary school and 2.5 ha of public space.
The size of the excavation for the contract is 160,000 cu m. Some 97% of fill material is being processed from site excavation. This includes crushing and screening of concrete and bio remediation of contaminated soils.
“Space is at a premium, so there has been considerable planning for such an extensive earthworks operation while separating out hazardous material from the old gasworks,” says Scholey. “It is not just a cut and fill job, it is more like a jigsaw puzzle.”
Top: The vast Nine Elms development site is a patchwork of former buildings and utilities. Above: The site is fringed by new housing, requiring careful liaison
The site clearance included discovery of two large-diameter Thames Water pipes running beneath the area to be excavated. As Scholey says: “The greatest challenge was understanding how the pipe would react with the removal of the material above due to the mix of construction materials used over time to maintain the sewer.
“The sewer comprised cast iron/brickwork and concrete at various sections along the length of the run. We needed to engage geotechnical experts in order to determine the rate of upward movement of the pipeline due to the London clay lying beneath.
“This resulted in a change in methodology of excavation to ensure no cracks formed due to upward movement,” he adds.
Material has to be carefully tracked as part of the remediation verification process. For this process, BAM has been using the PODfather. Scholey explains: “PODfather is an online tool that we use with PalmPilots, which tracks material movement via GPS around the site. It provides live updates on which materials are being moved where, in what volumes, and details of hazardous materials.”
With this location, another challenge that the project faced was dealing with the surrounding projects and changing local community. The whole Nine Elms area is undergoing around a £15bn makeover, so inevitably there are other contractors working nearby, as well as residents living in, or moving into, the new developments.
Scholey says they have kept an open dialogue with the council and local residents through a fortnightly newsletter and have also set up an “odour committee” to check if any of the hazardous materials become an issue for local residents.
He says the project is on track to complete in August this year.