Gas works: Risk assessment, Remediation and Materials Management Planning

Materials Management Remediation Site Assessments

A former gas works site was successfully approved for redeveloped into retirement apartments after multiple phases of investigations, monitoring and risk assessment proved that the required pile foundation work would not impact to the underlying sensitive groundwater resource. This was a complicated site with significant contamination levels and complex hydrological regimes to consider. An MMP was also used to manage reuse and removal of soils on site.

Project: Redevelopment of former gasworks into retirement apartments with managed landscaped areas. EPS supported the client from feasibility to final validation. A preconstruction assessment was carried out during foundation reveal of the former gas holder to assist a piling risk assessment, also continuous downstream monitoring of groundwater was undertaken during enabling and piling works to monitor the impact to the groundwater resource and receptors downstream.

Scope: SI comprised 3 x 20m and 16 x 8m boreholes and 4 trial pits. Full geotechnical and environmental testing, groundwater monitoring, MMP. Factual and interpretive reporting, liaison with CLO, support with NHBC warranty requirements.

Nature of site: A former gas works in the western part which prior to works was operating as a car dealership. The eastern half was a derelict warehouse with a history of use as a coating/product finishing factory. Sensitive location within a SPZ and underlain by a principal aquifer. Groundwater was found to be in continuity with the shallow contaminated material.

Client: National housebuilder/developer.

Duration of works: 1.5 years, 13 separate project phases. Validation ongoing.

Value: Circa £45,000