Manuherikia Catchment Group Incorporated Overview of Proposed Catchment Management Approach Prepared by McKeague Consultancy February 2021 Quality Assurance Statement for: McKeague Consultancy Ltd | 16 Howard Street | Macandrew Bay| Dunedin 9014 Prepared by McKeague Consultancy Ltd: Sally Dicey, Susie McKeague, Ros Day Water Resource Management Ltd: Matt Hickey Landpro: Kate Scott, Christine Bright, Zoe McCormack WSP: Mike Kelly Reviewed by Susie McKeague Approved for issue by Susie McKeague This document has been prepared for the benefit of the Manuherikia Catchment Group Inc for the purpose of obtaining consents from the Otago Regional Council. No liability is accepted by this company or sub-consultant of this company with respect to its use by any other person. All rights reserved. No part of this tool may be reproduced, stored in a retrieval system or transmitted in any form by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of McKeague Consultancy Ltd. © McKeague Consultancy Limited Contents Executive summary ................................................................................................................................. 1 1. Development of a catchment proposal .......................................................................................... 4 2. Proposal Design ............................................................................................................................ 8 3. History of Water Management in the Manuherekia Catchment ................................................... 13 Existing Flow Sharing Agreements ................................................................................................ 14 Falls Dam Company Ltd - Operation and Rationing Regime ......................................................... 14 Manuherikia Catchment Water Strategy Group ........................................................................... 16 4. Physical Setting ........................................................................................................................... 18 4.1 Climate .................................................................................................................................. 18 4.1.1 Climate Change ................................................................................................................. 19 4.2 Land Use and Topography .................................................................................................... 20 4.3 Hydrology .............................................................................................................................. 21 4.4 Aquatic Ecology ..................................................................................................................... 22 4.5 Water Quality ........................................................................................................................ 23 5. Proposed Future Management of Water in the Manuherikia Catchment ..................................... 25 5.1 Flow Management Zones ...................................................................................................... 25 5.2 Regulatory Management Sites and Reference Sites ............................................................. 27 5.2.1 Three Tiered Approach to Flow Limits .............................................................................. 27 5.2.2 Flow Sharing to Support Flow Limits ................................................................................. 30 5.3 Above Falls Dam Management Zone .................................................................................... 31 5.4 Manuherikia Mainstem Management Zone ......................................................................... 32 5.4.1.1 Below Falls Dam ................................................................................................................ 33 5.4.1.2 Ophir ................................................................................................................................. 34 5.4.1.3 Campground ...................................................................................................................... 35 5.4.1.4 Residuals on Main Stem takes from the Manuherikia -Blackstone, Omakau, Manuherikia, Galloway schemes ............................................................................................................................. 36 5.4.2 Tributary Sub-catchments within the Manuherikia Mainstem Management Zone ......... 37 5.4.2.1 Dunstan Creek ................................................................................................................... 39 5.4.2.2 Lauder Creek and Thomson Creek .................................................................................... 40 5.4.2.3 Chatto Creek ..................................................................................................................... 41 5.4.2.4 Manor Burn ....................................................................................................................... 42 5.5 Ida Valley Management Zone ............................................................................................... 43 5.6 Residuals on individual takes. ............................................................................................... 45 5.7 Summary of Proposed Flow Limits During the Irrigation Season ......................................... 45 5.8 Proposed Winter Regime ...................................................................................................... 46 6. Irrigation and Allocation in the Manuherikia Catchment ............................................................... 47 6.1 Adaptation and development suited to lower summer flows .............................................. 50 6.2 What does this mean for allocation in the Manuherikia Catchment under the NPSFM (2020) 51 6.3 Irrigation Scheme management of water use ...................................................................... 52 7. Methods Underpinning applications ............................................................................................ 53 7.1 Water Demand ...................................................................................................................... 53 7.2 Water required for irrigation ................................................................................................ 53 7.2.1 Irrigated Area .................................................................................................................... 54 7.2.2 Aqualinc (2017) and Reasonable Irrigation Demand ........................................................ 56 7.2.3 Water required for frost-fighting ...................................................................................... 57 7.2.4 Water required for fruit-cooling ....................................................................................... 59 7.2.5 Water required for stock drinking water .......................................................................... 60 7.2.6 Water required for domestic use ...................................................................................... 61 7.2.7 Distribution losses ............................................................................................................. 61 7.3 Analysis of Metering Data ..................................................................................................... 62 7.4 Allocation Sought in Applications ......................................................................................... 63 7.5 Value of Existing Investment ................................................................................................. 64 8. Catchment Level Assessment of Effects on the Environment ..................................................... 65 8.1 Existing Environment ............................................................................................................ 65 8.1.1 Dams and Weirs ................................................................................................................ 66 8.1.2 Water takes ....................................................................................................................... 67 8.2 Effects on Hydrology ............................................................................................................. 67 8.3 Effects on Water Quality ....................................................................................................... 70 8.4 Effects on Ecology ................................................................................................................. 71 8.5 Effects on Natural Character and Amenity ........................................................................... 73 8.6 Effects on Recreational Values.............................................................................................. 77 8.7 Effects on Cultural Values ..................................................................................................... 79 8.8 Effects related to Climate Change ........................................................................................ 85 8.9 Effects of Dams ..................................................................................................................... 86 8.10 Economic and Social Effects .................................................................................................. 87 8.11 Cumulative Effects ...............................................................................................................