BAM Nuttall is carrying out the remediation contract for the former South London Mail Centre in Nine Elms ahead of its redevelopment. Its location in one of the largest regeneration areas in London brings its own unique challenges.
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. The site will be redeveloped with high-rise homes, a primary school and 2.5 ha of public space.
The works include 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 Nuttall 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 challenges faced at Nine Elms.
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.
The site clearance included discovery of two large-diameter Thames Water pipes running beneath the area to be excavated. A 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.
Material has to be carefully tracked as part of the remediation verification process. For this process, we have been using the PODfather. PODfather is an online tool, 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.
The whole Nine Elms area is undergoing a £15bn makeover, so inevitably there are other contractors working nearby, as well as residents living in, or moving into, the new developments. We 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.
The project is on track to complete in August this year.