Oxford Station Redevelopment
Project Scope and Delivery
The SYSTRA Geo-Environmental team is working on the Oxford Station Redevelopment Scheme for Network Rail. As part of the outline design for the scheme, a ground investigation identified a potential contamination risk within one of the development areas. This potential contamination risk was raised by the Network Rail design team and SYSTRA was commissioned to develop and manage a contaminated land strategy on behalf of Network Rail.
Working closely with Network Rail and the design team, SYSTRA undertook contaminated land risk assessments to understand the level of risk and identified a remediation strategy to address the risks that aligned with the local constraints.
SYSTRA designed a delineation survey to define the contamination area and assess the relevant pollutant linkages. Using this survey, SYSTRA demonstrated that, although significant organic contamination was evident, the ground conditions at the site were suitable for the risk to the recognised watercourse receptor to be limited by installing a low permeability barrier along the pollution pathway. Additionally, using a Controlled Water Detailed Quantitative Risk Assessment, proactive remediation targets were developed for removal of contaminated material within the made ground and treatment of hydrocarbon contamination within the groundwater.
A remediation strategy was developed to meet these targets through application of Sustainable Remediation Forum initiatives, while also considering the operational needs of the site. This led to a proposal for a combined remedial approach, with localised excavation and disposal of the main contaminated area; ex-situ pump and treat of the perched groundwater within the made ground; localised oil skimming to reduce free phase oil; and monitored natural attenuation of the aquifer to monitor improvements against the remedial targets.