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 At the time of rehabilitation of tributary 2 any culvert requirements for the haul road will need to be retro-fitted to provide passage for climbing fish. 14.4.5 Fish Salvage and Relocation 14.4.5.1 Effects Instream works during construction have the potential to cause injury and/ or mortality to native fish. Some detail of construction methods is provided within the engineering reports associated with the resource consent application. The construction methods and sequencing are yet to be confirmed, but it is envisioned that any instream works will be constructed in a manner to avoid mortality to native fish. 14.4.5.2 Effects management Prior to overburden placement over tributary 2, fish salvage and relocation will occur to avoid the potential for fish mortality. Fish salvage and relocation will be carried out as set out more fully in a recommended Fish Management Plan for WNP. Instream works will be temporary (for the duration of construction) and potential injury and/or mortality of native fish will be avoided through fish relocation efforts. Provided fish salvage and relocation is conducted, the potential effect (likelihood) of fish mortality is very low. 14.4.6 Sediment Discharge to Receiving Environments 14.4.6.1 Effects Earthworks over the Willows Road Farm site as well as other proposed activities (i.e., vegetation clearance, drilling, excavation, and stock piling) have the potential to reduce the water quality within Mataura Stream through erosion and sediment runoff and potential contaminants from the rock stack. Excessive fine sediment within a stream has the potential to cover the streambed and smother the natural habitat or fill spaces between the larger substrates. Sediment can also be abrasive and damage the fine structures and gills of the biota. Some species occurring in the Mataura Stream are particularly sensitive to sediment intrusions, notably those that affix or graze on the hard substrates or capture food from the water column. Amongst those species are the freshwater bioluminescent limpet Latia neritoides (suction to hard substrate and grazes on biofilms), blackflies (silk and basal hook adherence to hard substrates; also filter feeds from the water column), net-spinning caddisflies (build cased homes and filter the water column through silk-spun nets), substrate-dwelling mayflies and stoneflies. These modifications can influence the food available to native fish. 14.4.6.2 Effects management An erosion and sediment control plan will be prepared as part of the proposed works for the components of the WNP project. Details of erosion and sediment control are outlined Erosion and Sediment Management Plan (OGNZL 2021). Due to the size of the WKP portal infrastructure footprint, a number of sediment ponds are likely to be required to manage sediment laden runoff to protect Mataura Stream from excessive sedimentation.

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