Supporting Technical Assessments

U:\2021\BM210482_IBo_Waihi_North_Project\Documents\WNP_Freshwater_Report_May_2022\FINAL_Freshwater_Report_FOR DELIVERY_June 2022\FINAL DELIVERED 17 JUNE 2022\WAI-985-000-REP-LC-0007_Rev0_Freshwater_20220621_FINAL.docx 12.3 Wetland Indigenous Biodiversity Significance The Willows Road Farm wetland contains two mature swamp maire trees which have been classified as ‘Threatened – Nationally Critical’, although we acknowledge that this is a precautionary measure based on the uncertainty surrounding myrtle rust. However, swamp maire is noted as being rare within the Waihi Ecological District (Kessels & Associates 2010). No other wetlands in the WNP project area meet the criteria as significant for indigenous biodiversity. 13.0 Water Treatment Plant Reconsenting 13.1 Introduction The Waihi North Project will utilise the existing WTP to treat water from the mining operations. The Waihi North Project will not result in any different types of water requiring treatment and water being conveyed to the WTP for treatment will continue to come from across the Waihi Epithermal District. OGNZL holds resource consents that provide for the discharge of treated water from the WTP to the Ohinemuri River via multi-port diffusers at two consented locations (“WTP Discharge Consent”). The current WTP Discharge Consent authorises the discharge of treated water into the Ohinemuri River under five different operating regimes, with each operating regime containing specific controls in relation to discharge volume, rate, the percentage of discharge relative to river flow and discharge quality. GHD (2022A) concluded that, based on the water balance analysis completed, it is predicted that the Waihi North Project can be implemented using the existing and upgraded WTP functionality, and within the current consent discharge and receiving environment conditions, subject to renewal of those consents for an appropriate term. The capacity of the current WTP facilities will require upgrading throughout the project’s lifetime to cope with the expected volume of water requiring treatment. No changes to the water quality limits from the discharge from the WTP are required to accommodate the Waihi North Project. Nevertheless, in this section we consider the various guidelines for water quality applicable to the Ohinemuri River, and the effectiveness of the existing water quality criteria provided for in the respective guidelines and resource consents on the ecological values of the Ohinemuri River. In section 19, we go on to consider the appropriateness of retaining the existing instream water quality criteria for the protection of instream ecological values. 13.2 Water quality guidelines 13.2.1 National Policy Statement Freshwater Management 2020 (NPSFM) The NPS-FM came into effect in September 2020. As outlined in Section 5.2 above, the NPSFM requires regional councils, through their regional plans, to set freshwater objectives that

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