Appendix F. Ecological Assessment Report Williamson Water & Land Advisory Limited 1 Te Ruaotehauhau Stream Water Storage Reservoir Preliminary Assessment of Ecological Values and Effects 1 September 2020 puhoistour.co.nz PUHOI STOUR LIMITED LYSAGHT BUILDING | 101 PAKENHAM STREET AUCKLAND 1010 Te Ruaotehauhau Stream Water Storage Reservoir – Preliminary Assessment of Ecological Values and Effects Prepared by Puhoi Stour Ltd in association with Tonkin & Taylor Ltd. Alicia Wong, Sam Heggie-Grace, Justine Quinn, Josh Markham, Trevor Connolly, Martin Neale. Document History PSL Report Number 2020/11 Version Date Reviewed by Draft for PSL review 27/08/2020 Martin Neale Final 28/08/2020 Martin Neale PUHOI STOUR | PAGE 2 Table of Contents Table of Contents ........................................................................................................................................................................... 3 1. Introduction ............................................................................................................................................................................ 5 2. Site description ...................................................................................................................................................................... 5 3. Methods ................................................................................................................................................................................. 7 3.1 Desktop assessment .................................................................................................................................................... 7 3.2 Freshwater values assessment .................................................................................................................................... 8 3.2.1 Stream classifications .......................................................................................................................................... 8 3.2.2 Macroinvertebrates .............................................................................................................................................. 8 3.2.3 Fish ...................................................................................................................................................................... 9 3.2.4 Stream ecological valuation ............................................................................................................................... 10 3.3 Terrestrial values assessment .................................................................................................................................... 11 3.3.1 Ecosystem types ................................................................................................................................................ 11 3.3.2 Bats .................................................................................................................................................................... 12 3.3.3 Birds ................................................................................................................................................................... 12 3.3.4 Herpetofauna ..................................................................................................................................................... 12 3.3.5 Invertebrates ...................................................................................................................................................... 13 3.4 Assessment of effects................................................................................................................................................. 13 4. Freshwater ecological assessment ..................................................................................................................................... 13 4.1 Freshwater values ...................................................................................................................................................... 13 4.1.1 Stream classification and values ........................................................................................................................ 13 4.1.2 Macroinvertebrates ............................................................................................................................................ 15 4.1.3 Freshwater fauna ............................................................................................................................................... 15 4.1.4 Summary of freshwater ecology values ............................................................................................................. 16 4.2 Assessment of ecological effects - freshwater ............................................................................................................ 16 4.2.1 Sedimentation during construction ..................................................................................................................... 16 4.2.2 Injury or mortality of freshwater fauna ................................................................................................................ 17 4.2.3 Fish passage ...................................................................................................................................................... 18 4.2.4 Permanent modification of stream habitat .......................................................................................................... 19 4.2.5 Downstream water quality effects ...................................................................................................................... 21 4.2.6 Downstream habitat effects ............................................................................................................................... 22 5. Terrestrial and wetland ecological assessment ................................................................................................................... 22 5.1 Terrestrial ecological values .............................................................................................................................................. 22 PUHOI STOUR | PAGE 3 5.1.1 Pūriri forest (WF7.2) ........................................................................................................................................... 23 5.1.2 Riparian swamp forest (WF8) ............................................................................................................................ 23 5.1.3 Secondary broadleaf forest with old-growth remnants (VS5) ............................................................................. 24 5.1.4 Tōtara treeland (AVS1) ...................................................................................................................................... 24 5.1.5 Volcanic boulderfields ........................................................................................................................................ 24 5.1.6 Exotic forest ....................................................................................................................................................... 25 5.1.7 Indigenous-dominated wetlands ........................................................................................................................ 25 5.1.8 Wet pasture grass .............................................................................................................................................. 25 5.1.9 Bats .................................................................................................................................................................... 25 5.1.10 Avifauna ............................................................................................................................................................. 26 5.1.11 Herpetofauna ..................................................................................................................................................... 27 5.1.12 Invertebrates ...................................................................................................................................................... 27 5.2 Assessment of ecological effects - terrestrial............................................................................................................. 28 5.2.1 Vegetation effects .............................................................................................................................................. 28 5.2.2 Fauna effects ..................................................................................................................................................... 31 5.2.3 Fauna effects management ............................................................................................................................... 31 5.2.4 Measures to reduce fauna ecological effects summary ..................................................................................... 33 6. Recommendations to manage effects ................................................................................................................................. 35 7. Report applicability .............................................................................................................................................................. 37 8. Appendices .........................................................................................................................................................................