ECOLOGICAL ASSESSMENT FOR CONSTRUCTION OF A PROPOSED IRRIGATION SCHEME SOUTH OF THE HURUNUI RIVER, IN NORTH CANTERBURY R5004 ECOLOGICAL ASSESSMENT FOR CONSTRUCTION OF A PROPOSED IRRIGATION SCHEME SOUTH OF THE HURUNUI RIVER, IN NORTH CANTERBURY Contract Report No. 5004 June 2020 Project Team: Des Smith - Project manager and report author Melanie Lapointe - Field survey and report author Peter Heenan - Field survey and report author Jamie MacKay - Field survey and report author Carey Knox - Field survey and report author Brian Patrick - Field survey and report author Stella McQueen - Report author Erin Gallagher - Field survey, report author William Shaw - Peer review Prepared for: Amuri Irrigation Company Ltd 50 Mountainview Road PO Box 194 Culverden 7345 CHRISTCHURCH OFFICE: 7A VULCAN PLACE, MIDDLETON, CHRISTCHURCH 8024; P.O. BOX 9276, TOWER JUNCTION, CHRISTCHURCH 8149; Ph 03-338-4005 HEAD OFFICE: 99 SALA STREET, P.O. BOX 7137, TE NGAE, ROTORUA Ph 07-343-9017; Fax 07-343-9018, email [email protected], www.wildlands.co.nz CONTENTS 1. INTRODUCTION 1 2. PROPOSED WORKS 1 3. METHODS 2 3.1 Overview 2 3.2 Literature review 2 3.3 Field visits 2 3.4 Vegetation 2 3.5 Avifauna 4 3.6 Lizards 4 3.7 Terrestrial invertebrates 5 3.8 Stream surveys 6 3.9 Fish and aquatic macroinvertebrates 6 3.10 Ecological significance assessment 6 4. ECOLOGICAL CONTEXT 7 4.1 Ecological districts 7 4.2 Protected areas 7 4.3 Recommended areas for protection 9 4.4 Hurunui River and its tributaries 9 4.5 Other ecological sites recorded previously 10 5. TERRESTRIAL VEGETATION, HABITATS, AND SPECIES 10 5.1 Overview 10 5.2 Ecological significance assessment 10 5.3 Vegetation and flora 10 5.4 Avifauna 12 5.5 Lizards 15 5.6 Terrestrial invertebrates 18 5.7 Terrestrial vegetation and habitat sites 19 Hurunui River intake 21 Hurunui River Marginal Strip 22 Waitohi River Terraces 25 Rank grass as lizard habitat 25 Other surveyed sites 26 6. AQUATIC HABITATS AND SPECIES 32 6.1 Surface water quality 32 6.2 Aquatic fauna 34 Fish 34 Macroinvertebrate communities 36 6.3 Aquatic habitats 37 Hurunui River intake 37 Stream and river crossings 40 © 2020 Contract Report No. 5004 7. POTENTIAL ECOLOGICAL EFFECTS AND MEASURES TO AVOID, REMEDY AND/OR MITIGATE POTENTIAL ADVERSE EFFECTS 44 7.1 Overview 44 7.2 Construction effects on terrestrial vegetation and palustrine wetland habitats 44 Hurunui River intake and sediment pond site 44 Hurunui River Marginal Strip 46 Waitohi River terraces 48 Rank grass habitats for lizards 49 Other surveyed sites 50 Exotic pest plants/woody weeds/algae 50 7.3 Operational effects on terrestrial vegetation and habitats 50 7.4 Operational effects on aquatic habitats and surface water quality 51 Overview 51 Disturbance and loss of aquatic fauna habitat at the intake 51 Disturbance and loss of aquatic habitat across the pipeline alignment 54 Entrainment, impingement, and mortality of aquatic fauna 55 Sedimentation 57 Spills and contamination 59 Alteration of watercourse hydrology 59 Fish passage restrictions 60 Reduced functioning of riparian margins 60 Spread of didymo and pest plants 61 Cumulative effects 61 7.5 Measures to avoid, remedy, and/or mitigate potential adverse effects 62 Guidelines on fish salvage 63 Other measures 65 7.6 Overall assessment 65 8. CONCLUSIONS 66 ACKNOWLEDGMENTS 68 REFERENCES 68 APPENDICES 1. Proposed irrigation infrastructure and operational requirements 74 2. Ecological district overviews 87 3. Rapid stream assessment data sheet 89 4. Bird records for the Hurunui River 90 5. Results from rapid stream assessments 91 6. Fish species in the Hurunui Catchment, from NZFFD data 94 7. Macroinvertebrate results 99 8. Ecological significance assessment 100 © 2020 Contract Report No. 5004 Reviewed and approved for release by: _______________________ W.B. Shaw Director/Principal Ecologist Wildland Consultants Ltd Wildland Consultants Ltd 2020 This report has been produced by Wildland Consultants Ltd for the Amuri Irrigation Company Ltd. All copyright in this report is the property of Wildland Consultants Ltd and any unauthorised publication, reproduction, or adaptation of this report is a breach of that copyright. © 2020 Contract Report No. 5004 1. INTRODUCTION Amuri Irrigation Company Ltd (Amuri) has completed a takeover of Hurunui Water Project Ltd (HWP). Through this amalgamation, Amuri have secured the existing HWP resource consents that will enable irrigation to occur south of the Hurunui River and to provide water for irrigation to landowners in the Hurunui District. Amuri also wishes to secure construction-related consents to irrigate up to 4,000 hectares of land. The scope of works requires construction of a water intake in the Hurunui River, a sediment pond at the intake site, clearance of vegetation, excavation and back-filling of trenches, laying of an underground pipeline network, creation of storage ponds, and river and stream crossings. The project covers an area of 21,058 hectares and is centred on Hawarden. The northeastern boundary of the project area is bounded by the Hurunui River downstream from the Mandamus River confluence (Figure 1). The eastern limit of the project area follows SH7 until it reaches the Waikari River valley through to the start of the Scargill Valley. The southern limit follows the Waikari River valley up to Pyramid Valley. The western boundary skirts the foothills of the Southern Alps. This report comprises an ecological review drawing on the results from various ecological surveys and an assessment of ecological effects. This will support the resource consent application for the construction of the irrigation scheme. Specifically, this report addresses potential effects on: x Terrestrial ecology, including vegetation, lizards, and invertebrates. x Aquatic ecology, including avifauna, as well as surface water quality. This assessment does not address the effects of water abstraction and the use of water for irrigation (which has already been consented). Existing resource consents (CRC120675, CRC190085, CRC172780) have authorised the taking and use of water for irrigation associated with this project. This ecological assessment addresses the potential ecological effects of constructing and maintaining the water intake, sediment pond, pipelines, and other associated infrastructure (described in the next sections). This includes assessment of the location and design of the ‘in the water’ infrastructure such as the intake channel and the discharge channel, and any related vegetation clearance. The aquatic ecological assessment also considers whether the fish screen design meets the requirements of consent CRC190085 and the standards set out by NIWA (2007). 2. PROPOSED WORKS Proposed works include the construction of an intake channel in the bed of the Hurunui River, diversion of the river bed to manage braided channels, a sediment pond, and an underground pipeline network south of the Hurunui River. This ecological assessment is for construction and maintenance of the irrigation infrastructure (water intake, sediment pond, pipe alignments) based on preliminary plans provided in March 2020 (Figure 1). © 2020 1 Contract Report No. 5004 Descriptions and construction methods for the following infrastructure requirements are provided in Appendix 1: x Hurunui River intake (Riley Consultants 2020). x Pipeline alignments (Beca 2020). Operational requirements are also described in Appendix 1. 3. METHODS 3.1 Overview This assessment provides an evaluation of ecosystems, habitats, species, and ecological values in the project area based on a literature review and field surveys. Construction of infrastructure and ongoing maintenance of that infrastructure has been addressed in this assessment. Effects associated with operation of the irrigation scheme are addressed in existing consents. 3.2 Literature review To evaluate the ecological values of the site within a wider context, a literature search was undertaken for relevant existing ecological information. The literature search included databases such as the Department of Conservation Herpetofauna Database, New Zealand Freshwater Fish Database, and eBird, and ecological reports, including information previously gathered by Amuri and Hurunui Water Project Ltd. 3.3 Field visits Field visits took place from 11 April to 1 May 2019 and covered the entire project area (Figure 1). An additional field visit was undertaken on 28 February 2020 to assess the-proposed intake site within the Hurunui River bed and a Department of Conservation marginal strip. 3.4 Vegetation Routes of the proposed pipelines and proposed intake site were initially surveyed on 23 April 2019, and, following pipeline realignment and a new intake location, were resurveyed on 28 February 2020. These surveys aimed to identify, describe, and assess the vegetation and habitats present, evaluate ecological values, and assess potential effects on indigenous vegetation and habitats. Photographs were taken to illustrate issues and points of interest. The surveys aimed to characterise areas rather than a specific point location, and to identify vegetation and habitats of ecological value. © 2020 2 Contract Report No. 5004 © 2020 3 Contract Report No. 5004 3.5 Avifauna A search of the eBird database was undertaken to see whether the database held records of any threatened bird species observed within a 10 kilometre radius of the existing Amuri intake on the Hurunui River. ‘eBird’ is a citizen science, global, on- line checklist database programme. Observations of single birds through to checklists