3. Summary of Soil and Groundwater Quality

Investigations of soil contaminant concentrations were completed in support of the wider CRL project. In relation to the Aotea station area, the investigations (refer references in Section 9) identified that significant soil contamination was unlikely to be encountered during land disturbance activities. Soil analyses completed did not exceed the permitted activity contaminant concentrations outlined in the Ministry for the Environment (MfE) Resource Management National Environmental Standard for Assessing and Managing Contaminants in Soil to Protect Human Health Regulations 2011 (NES CS) and Auckland Unitary Plan Operative in Part (AUP) Permitted Activity Criteria. Existing documentation indicates that there is a low probability of encountering large scale contamination within the works area. This includes groundwater contamination.

There is however, the potential to encounter gravel type fill materials (surface to approximately 2m below ground level) for which soil contaminant concentrations (heavy metals or heavy end hydrocarbons) may be in the order of applicable standards defined by the NES CS and AUP. The primary source of potential contamination within the works area relates to the presence of fill of unknown origin. This is largely due to the fact the works are to be completed within an urban setting comprising road infrastructure. In addition, asbestos is likely to be present in the underground wastewater and stormwater pipes due to the age of these network utilities.

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Aotea Station Main Works