Smart Soil Strategies for Brownfield Development
- Client Name
- Argosy Property
- Location
- Auckland, New Zealand
Challenge
Argosy was seeking to establish a sustainable large scale commercial development on a brownfield site with a long industrial history. The site is adjacent to a Significant Natural Area (SNA), and overlies a volcanic aquifer that is used as a metropolitan drinking water supply.
SLR’s Land Quality & Remediation team undertook preliminary site investigations which identified an extensive history of industrial use, including steel pipe manufacturing and landfilling. Detailed investigations identified a variable soil profile across the site, and the presence of a range of contaminants in soil.
Argosy was seeking to meet Green Star standards for the build, and was keen to explore beneficial reuse of soil and construction material where possible.
Solution
SLR worked closely with Argosy, the Principal Contractor, and a range of other contractors to manage the risks associated with contaminants in soil, and to identify beneficial and sustainable reuse opportunities for both soil and construction material across all stages of the development (demolition, earthworks, civil).
Utilising data obtained from site investigations, SLR established a system to categorise soil for reuse. Soil with elevated concentrations of contaminants was subject to onsite stabilisation and placement, following bench and field tests which confirmed stability of contaminants and geotechnical suitability. Asbestos contaminated concrete was crushed under suitable controls on site to be reused as basecourse. Both these initiatives resulted in significant diversion of soil to landfill, and minimized the need to rely on imported aggregate.
A range of on site controls were established to manage contaminants in situ to minimize the risk to human health or the environment. Monitoring of the receiving environment was able to demonstrate there was no evidence that retention of soils on site would present an unacceptable risk to human health or the environment.
Impact
Our focus on soil and construction material reuse has resulted in significant cost savings for the client. It has also avoided large scale excavation and off site disposal requirements, with associated transport costs and emissions.
This approach has also contributed to meeting Argosy’s sustainability targets, and the desired outcomes of achieving a Green Star rated commercial building.
