ENGEO was engaged by Fletcher Residential Limited to initially complete a detailed site investigation (DSI) for land known as Super Lot 05 within the Eastern Frame of Christchurch. The land was previously used for various commercial uses and was acquired by the Crown as part of the post-Canterbury-earthquakes Christchurch City redevelopment. The site, with an area of 6,205 m2 located close to the Central Business District, was rezoned for high-density residential development.
ENGEO provided the full range of environmental assessment services, with the exception of a preliminary site inspection, which was provided by the landowner’s consultant. The initial engagement was for completing a DSI of the entire site. As ENGEO had not completed the PSI previously, we reviewed this and completed a data-gap analysis with any information gaps to be further assessed during the DSI.
Initial consultation with Heritage New Zealand and their archaeologists was also required during the DSI as the site was registered as having pre-1900 land activity. The appropriate permissions were obtained and information on the fill material was provided to the archaeologist.
Underground service owners were contacted for asset plans prior to completing the DSI and were notified of ENGEO’s intention to excavate close to their assets.
The project involved consultation with a lot of varied stakeholders. As the land was Crown land, Ōtākaro Limited, the entity for delivering Crown-led Anchor Projects in central Christchurch and divesting the balance of Crown land, was a primary stakeholder. Ōtākaro and their consultants were consulted during the DSI peer review process until a satisfactory agreement on residual petroleum hydrocarbon risk could be found.
Due to the site’s long and varied history, several areas of land contamination were identified. Contaminants included petroleum hydrocarbons, asbestos, polycyclic aromatic hydrocarbons and heavy metals. For geotechnical reasons, a large volume of fill material was required to be excavated and removed from the site. ENGEO completed additional assessments to characterise the waste material to provide recommendations for the most cost-effective disposal location.
Following the DSI, ENGEO’s scope of works was increased to provide a remedial options appraisal, remedial cost benefits assessment, resource consent assistance, additional supplementary DSI works on the site, consultation with stakeholders including Otakaro and their environmental consultants, and consultation with Christchurch City Council environmental health officers and Environment Canterbury.
During the consent process, ENGEO consulted with both Christchurch City Council (CCC) and Environment Canterbury (ECan) regarding the proposed consent conditions and ensuring they were suitable for the client and suitably protective of human health and the environment.
ENGEO consulted with CCC extensively on their implementation of the UK Water Industry Regulation Guidance for the Selection of Water Supply Pipes to be used in Brownfield Sites. CCC were requiring strict adherence to the guideline, which would have meant the majority of the site to be excavated to a depth of one metre. ENGEO successfully enabled them to agree to a more risk-based approach and therefore avoided the need for further soil removal.
Following the granting of land-use consents from CCC and resource consents for the discharge of contaminants to land and water from ECan, ENGEO was retained by Fletchers to provide a site management plan for the works, a long-term site management plan for the body corporate, and consent compliance during the works.
“ENGEO was appointed to provide Environmental Engineering Services on Super Lot 5 within the One Central (formerly East Frame) development. This was a high profile site and a responsive and pragmatic approach to the proposed remediation strategy was necessary. ENGEO more than fulfilled the brief, delivering comprehensive and timely advice that specified, in understandable language, the potential paths to compliance and the relative merits of each. They were easy to deal with and very knowledgeable, utilising their industry experience and relationships to smoothly negotiate the consenting pathway”
Thanks to the project team involved; Sean Freeman, Daniel Kaminski, Gareth Oddy and Dave Robotham