As local authorities continue to face strong pressure to permit development on brownfield land, the cost of remediation works remains high. It is widely acknowledged that brownfield land presents positive opportunities for the development of much-needed housing and amenities while improving the aesthetic value of disused industrial sites.
It is understandably preferable that necessary development takes place on brownfield rather than greenfield land and does not eat up the green belt. As developers struggle to recoup their costs in an economically difficult climate, the cost of remediation can make the ideal planned development unviable.
RPS has successfully secured planning permission for 400 new homes at St. Mary’s Park in Maidenhead at appeal, despite the proposed development’s shortfalls in relation to adopted council standards for S106 and affordable housing. The site, believed to be one of the most contaminated in the UK, had been the subject of unlicensed tipping and required extensive remediation works estimated at around £28m.
RPS experts were able to demonstrate that the cost of such significant remediation works meant that the developer could not deliver a financially viable outcome without reduced S106 payments, and no affordable housing provision. Significantly, the Planning Inspector noted that the developer was best placed to identify acceptable profit margins for a scheme, and, with the Secretary of State, concluded that the environmental benefit of remediating the land greatly outweighed the acknowledged shortfalls.
In order to accurately assess the extent of contamination to an area of land, a robust site investigation must be carried out, and an appropriate Conceptual Site Model (CSM) compiled before the remediation strategy can be designed. The CSM must work within the context of the proposed end use for the site, and identify contaminant sources and possible pathways and receptors.
As a recent case study, site remediation is now scheduled to begin shortly on a site on behalf of Shepway District Council, which has been identified under Part 2(a) of the Environmental Protection Act. Previous remediation had been insufficient and unacceptable contamination levels had been discovered to remain. RPS was engaged to assist in resolving the problem, where contamination on the site was found to be present to a significant depth.
The CSM found there were no volatile contaminants in the soil, so the risks would only exist in direct contact, dust generation, or ingestion of the contaminated soil. This enabled the design of an effective remediation strategy to install a 600mm barrier level of imported clean soil, removing the risks of subsidence and the expense that extraction of the affected soil would pose. Further cost savings were made as RPS was able to secure a DEFRA Capital Grant for the remediation works also.
RPS is an approved supplier under the OGC Buying Solutions Framework agreement, and has extensive remedial expertise in site investigation, quantative and qualitative risk assessment, remedial design, supervision and completion reporting.
Contact:
Maidenhead scheme:
David Green
T: +44 (0) 161 237 9858
E: david.green@rpsgroup.com
Remediation of existing residential site:
Rob Glavin
T: +44 (0) 20 7939 8000
E: glavinR@rpsgroup.com