Supporting Technical Assessments

Waihi North Project Preliminary Site Investigation (Ground Contamination) Williamson Water & Land Advisory Limited 30 3. HAIL Assessment Summary This section provides a review of historical and current activities to determine whether any industries or activities listed on the HAIL have occurred on the various project sites. The findings of the HAIL review inform the requirement and scope for pre-works soil sampling, and provides the basis for the NESCS resource consent application. This section describes the method for reviewing the land use history and describes the HAIL assessment findings and potential for ground contamination (if any was identified), of each area of the WNP. The location(s) and nature of HAIL activities identified across the WNP areas are provided as Figures 12 to 18. 3.1 Site history review methodology The land use history of each WNP site was determined through review of historical aerial imagery dating back to the 1940s sourced from Retrolens, an online imagery database, and Google Earth. The historical imagery was then georeferenced to the various project areas in QGIS. The findings of the aerial imagery review, alongside images from key imagery dates, is provided for each area of the WNP in Appendix A. WRC’s Land Use Information Register (“LUIR”) was searched for each of the WNP areas to identify properties known to be contaminated on the basis of chemical measurements, or potentially contaminated on the basis of past land use. The LUIR search findings are provided in Appendix A. OGNZL provided records of their dangerous goods stock inventories, their fire event records, and spill event records, and files giving an overview of site operations and dangerous goods storage facilities and handling procedures. This data is also summarised in the relevant parts of Appendix A. Based on the site history review and the site walkover descriptions (Section 2.2), a HAIL assessment has been undertaken for each WNP site. The HAIL assessment determines how likely it is for each potential source of contamination to have resulted in contamination that may be intersected by the proposed WNP works. Descriptions of the WNP works have been summarised from the Project Description, with figures and further information provided within the Project Description document. In each table in the following sections, HAIL activities highlighted in red have the highest risk, orange has a moderate risk and green where no human health or environmental risks are expected (i.e., not a HAIL in the context of the project; HAIL activities H and I are only ‘triggered’ when contaminant concentrations exceed thresholds relevant to the works being proposed).

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