Draft Waipara River and Tributaries Environmental Flow Regimes Report No. R07/10 White Gorge Flow recorder site looking upstream: Photo Herb Familton ECan, 14th March 2006. ISBN 978-1-86937-639-0 MAY 2008 58 Kilmore Street 75 Church Street P O Box 345 P O Box 550 CHRISTCHURCH TIMARU Phone: (03) 365 3828 Phone: (03) 688 9069 Fax: (03) 365 3194 Fax: (03) 688 9067 Website: www.ecan.govt.nz Customer Services Phone 0800 324 636 Contents 1. Introduction ............................................................................................................... 1 1.1 Background................................................................................................................. 1 1.2 Important background information to aid understanding of this report ....................... 1 1.3 Terms and Abbreviations............................................................................................ 4 1.4 Allocation regimes/allocation blocks ........................................................................... 4 1.5 Description of the water resource units of the catchment........................................... 6 2. Hydrology and abstractions .................................................................................... 8 2.1 Background................................................................................................................. 8 2.2 Surface water.............................................................................................................. 8 2.3 Waipara Surface and Groundwater System ............................................................. 10 2.4 Flows to lagoon......................................................................................................... 11 2.5 Existing Upper Waipara abstractions........................................................................ 12 2.6 Existing Lower Waipara abstractions........................................................................ 14 2.7 Implications of the Tutton Sienko et. al. decision ..................................................... 14 2.8 Viticulture .................................................................................................................. 15 2.9 Stream Depletion Effects .......................................................................................... 16 2.10 Plantation Forestry and Willows ............................................................................... 16 2.11 Impact of water storage on catchment hydrology..................................................... 17 2.12 Water storage potential............................................................................................. 17 3. Upper Waipara instream values and their flow requirements............................ 18 3.1 Indigenous fish - Objective WQN1(b) ....................................................................... 18 3.2 Indigenous riverbed birds - Objective WQN1(b)....................................................... 18 3.3 Flows needed to provide for cultural values -Objective WQN1(c)(d)........................ 18 3.4 Flows needed to provide for natural character, landscape values and natural features - Objective WQN1(f).................................................................................... 19 3.5 Trout and salmon -Objective WQN1(g) .................................................................... 20 3.6 Flows needed to provide for amenity/recreation values (Objective WQN1 (h)......... 21 3.7 Flows needed to remove excessive periphyton, fine sediment, and invading woody weeds........................................................................................................................ 22 3.8 Summary of flow requirements for instream values ................................................. 23 4. Reliability of supply for the Upper Waipara ......................................................... 25 4.1 Importance of reliability of supply ............................................................................. 25 4.2 Assessment of the impact of restrictions for 1988 – 2005........................................ 25 4.3 Effect of restrictions: ................................................................................................. 25 4.4 Reliability of Supply Upper Waipara and the frequency and duration of restrictions 26 5. Evaluation of minimum flow monitoring sites and options for the Upper Waipara .................................................................................................................... 30 5.1 Introduction ............................................................................................................... 30 5.2 Minimum flow monitoring site Upper Waipara mainstem ......................................... 30 DRAFT STAFF REPORT ON WAIPARA RIVER AND TRIBUTARIES PROPOSED FLOW AND ALLOCATION MANAGEMENT REGIME i (NOT COUNCIL POLICY) 5.3 Comparative evaluation of minimum flow options (50L/s; 80L/s; 110L/s) against proposed NRRP Objective WQN1............................................................................ 30 5.4 Weighing of Weka Creek instream and out-of-stream values .................................. 33 6. Allocation limits – Upper Waipara......................................................................... 34 6.1 A allocation blocks .................................................................................................... 34 6.2 Cumulative effects of allocation ................................................................................ 34 6.3 Freshes and floods ................................................................................................... 35 6.4 Upper Waipara A allocation block options................................................................ 35 6.5 Upper Waipara B allocation block............................................................................. 39 6.6 C allocation block cut-off limits and block size for Upper Waipara mainstem .......... 40 6.7 Weka Creek allocation blocks................................................................................... 40 7. Lower Waipara instream values and their flow requirements............................ 41 7.1 Lower Waipara River mainstem................................................................................ 41 7.2 Objective WQN1 values and flow requirements for Home Creek............................. 43 7.3 Objective WQN1 values and flow requirements for Omihi Stream........................... 44 8. Reliability of Supply for the Lower Waipara......................................................... 45 9. Evaluation of monitoring sites and minimum flow options for the Lower Waipara .................................................................................................................... 47 9.1 Minimum flow monitoring sites.................................................................................. 47 9.2 Evaluation of minimum flows .................................................................................... 47 10. Allocation Limits – Lower Waipara ....................................................................... 54 10.1 Lower Waipara Block Options .................................................................................. 54 10.2 Home Creek A and B blocks..................................................................................... 55 10.3 Omihi Stream A and B Blocks .................................................................................. 56 11. Other matters .......................................................................................................... 57 11.1 Average daily take versus maximum rate of take..................................................... 57 11.2 Phasing in of any new environmental flow and allocation regimes .......................... 57 11.3 Flow sharing.............................................................................................................. 58 11.4 Installation of water meters, data logging, and data transmission............................ 58 12. Appendices.............................................................................................................. 61 12.1 Appendix 1 - recommendations of the review........................................................... 61 12.2 Appendix 2 - list of Waipara River Technical Reports .............................................. 64 12.3 Appendix 3 - effect on abstractors of proposed changes in flow regime for Lower Waipara River, Home Creek, and Omihi Stream...................................................... 66 12.4 Assessment of the cost to abstractors of proposed changes to the flow management regime for the Waipara River below Omihi confluence ............................................ 74 12.4 Appendix 4 - Technical Panel field notes for Home Creek, Omihi Stream, and Weka Creek......................................................................................................................... 78 12.5 Appendix 5 - Statutory Acknowledgement for Waipara River................................... 86 12.6 Appendix 6 – attributes, technical information, and evaluation of main stem flow regime options .......................................................................................................... 88 II DRAFT STAFF REPORT ON WAIPARA RIVER AND TRIBUTARIES PROPOSED FLOW AND ALLOCATION MANAGEMENT REGIME (NOT COUNCIL POLICY) 12.7 Appendix 7 - White Gorge flow exceedance percentiles: October to April and May to September................................................................................................................