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 • Fish passage is to be maintained through any culverts installed in permanent or intermittently flowing waterways to allow the migration of eel species. • All native fish and trout within the working area are to be salvaged and relocated outside the area of works, prior to work starting. 18.2.5 Culverts and fish passage 18.2.5.1 Culverts Culverts will be installed at stream or overland flow path crossings. BECA (2022) state that culverts will typically be sized to accommodate the 20-yr storm flow. However, key culverts will be sized to the 100-year return event, where build-up of headwater and overland flow would have detrimental effects on infrastructure. Erosion protection devices will be installed where required. Typical scour protection and flow energy dissipation devices are discussed in BECA (2022). Culverts will either be concrete pipe or box culverts, subject to detailed design. 18.2.5.2 Fish passage requirements for culverts Regulations 62 and 63 of the NESF set out the information that is required to be collected and supplied to the Waikato Regional Council. That extent of detail is not provided here but the key culverts and their fish passage requirements are provided in Table 31 and located in Figure 27. Fish passage design should follow the guidance provided in the Fish Passage Guidelines (NIWA 2018), noting that these guidelines are for structures up to 4 m in length28. Table 31:Key Culverts at NRS and fish passage requirements. Locations of culverts shown in Figure 28. Culvert ID Design Storm AEP Approximate Length (m) Minimum Size (m) Fish passage requirements OHE_T8 1% 15-20 1.5 Passage for climbing fish required. OHE_TX 1% 15-20 1.05 Passage for climbing fish required. 28 The fish passage guidelines focus on the legislative requirements for providing fish passage and provide the necessary information to allow infrastructure designers to integrate the needs of fish into the design process.
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