Icon Site Environmental Management Plan 2006–2007
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Icon Site Environmental Management Plan 2006–2007 Published by Murray-Darling Basin Commission Postal Address GPO Box 409, Canberra ACT 2601 Office location Level 5, 15 Moore Street, Canberra City Australian Capital Territory Telephone (02) 6279 0100 international + 61 2 6279 0100 Facsimile (02) 6248 8053 international + 61 2 6248 8053 E-Mail [email protected] Internet http://www.mdbc.gov.au For further information contact the Murray-Darling Basin Commission office on (02) 6279 0100 This report may be cited as: The Chowilla Floodplain and Lindsay-Wallpolla Islands Icon Site Environmental Management Plan 2006–2007 MDBC Publication No. 33/06 ISBN 1 921038 99 3 © Copyright Murray-Darling Basin Commission 2006 This work is copyright. Graphical and textual information in the work (with the exception of photographs and the MDBC logo) may be stored, retrieved and reproduced in whole or in part, provided the information is not sold or used for commercial benefit and its source The Chowilla Floodplain and Lindsay-Wallpolla Islands Icon Site Environmental Management Plan 2006–2007 is acknowledged. Such reproduction includes fair dealing for the purpose of private study, research, criticism or review as permitted under the Copyright Act 1968. Reproduction for other purposes is prohibited without prior permission of the Murray-Darling Basin Commission or the individual photographers and artists with whom copyright applies. To the extent permitted by law, the copyright holders (including its employees and consultants) exclude all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or in whole) and any information or material contained in it. The development of an environmental management plan for The Chowilla Floodplain and Lindsay-Wallpolla Islands cannot, and is not intended to, affect or diminish any existing private rights to own or occupy land within the region covered by the plan, or the way in which such land is used in future. Contents EXECUTIVE SUMMARY VI INTRODUCTION 1 PART A: The Icon Site 3 1. Background 4 1.1 POLICY CONTEXT 4 1.2 SITE DESCRIPTION AND VALUES 4 2. Making a difference: improving the ecology of the Icon Site 7 2.1 OBJECTIVES 7 2.2 FLOW NEEDS 7 2.3 SHORT-TERM FLOW MANAGEMENT ACTIONS 8 3. Getting it right: Support systems and processes 9 3.1 ROLES AND RESPONSIBILITIES: CROSS BORDER ARRANGEMENTS 9 3.2 CONSULTATION 10 3.3 MONITORING, EVALUATION AND REPORTING 11 3.4 FURTHER INTEGRATION OPPORTUNITIES 12 3.5 MAKING TRADEOFFS: PRIORITISING COMPETING MANAGEMENT ACTIONS 12 3.6 MANAGING POTENTIAL LEGAL AND RISK ISSUES 14 PART B: The Chowilla Floodplain 15 4. General description 16 4.1 HYDROLOGICAL OPERATION 16 4.2 LAND TENURE 19 4.3 KEY VALUES: ECOLOGICAL, CULTURAL AND SOCIAL 20 5. Current condition 25 6. Threats 28 7. Objectives, targets and flow requirements 37 8. Current management opportunities 43 8.1 WEIR POOL MANIPULATION 43 8.2 OPERATION OF LOCAL STORAGES 45 8.3 RIVER MURRAY SYSTEM-SCALE OPERATIONAL CHANGE 46 8.4 WETLAND MANAGEMENT 47 8.5 WATERING PROJECTS/FLOODPLAIN IRRIGATION 49 8.6 LAND MANAGEMENT 50 8.7 POTENTIAL NEW OPTIONS 53 9. Long term management: Proposed actions 57 9.1 NEW FLOW CONTROL ENVIRONMENTAL REGULATOR ON DOWNSTREAM SECTION OF CHOWILLA CREEK 57 9.2 UPGRADE PIPECLAY CREEK WEIR, SLANEY CREEK WEIR AND BANK E 60 9.3 GROUNDWATER MANAGEMENT SCHEME 61 9.4 PREFERRED OPTIONS: COSTS AND TIMING 64 10. Management roles and responsibilities 65 11. Monitoring 66 PART C: Lindsay-Wallpolla Islands 72 12. General description 73 12.1 HYDROLOGY 73 12.2 LAND TENURE 75 12.3 KEY VALUES: ECOLOGICAL, SOCIAL, CULTURAL 75 13. Threats 79 14. Objectives and flow requirements 84 Chowilla Floodplain and Lindsay-Wallpolla Islands Icon Site Environmental Management Plan 2006-07 i 15. Current management opportunities 87 15.1 SOURCES OF ENVIRONMENTAL FLOWS 87 15.2 WATER DELIVERY 87 15.3 WEIR MANIPULATION 88 15.4 COMPLEMENTARY MANAGEMENT 89 15.5 GROUNDWATER MANAGEMENT 90 15.6 FUTURE OPTIONS 94 16. Future management: Proposed structures and flows for key sites 95 16.1 WEBSTER’S AND HORSESHOE LAGOONS 95 16.2 LAKE WALLAWALLA 102 16.3 PRELIMINARY OPERATING RULES 106 16.4 PREFERRED STRUCTURES 111 17. Management roles and responsibilities 114 18. Monitoring, evaluation and reporting 116 APPENDIX I: CHOWILLA INTEGRATED NRM PROJECT 127 APPENDIX II: LIST OF STRATEGIES AND PLANS RELATED TO THE EMP 129 APPENDIX III: VEGETATION GROUPS MAPPED ON CHOWILLA 131 APPENDIX IV: THREATENED PLANT ASSOCIATIONS AT CHOWILLA 135 APPENDIX V: RATED SPECIES OF FLORA AND FAUNA (CHOWILLA) 136 APPENDIX VI: LINDSAY AND WALLPOLLA ISLANDS FLOW PATHS 139 APPENDIX VII: FLOOD INUNDATION MAPS FOR LINDSAY ISLAND 149 APPENDIX VIII: BACKGROUND INVESTIGATIONS 150 Planning 150 APPENDIX IX: EVC MAPS FOR LINDSAY, MULCRA AND WALLPOLLA ISLANDS 151 APPENDIX X: PROPOSED SHORT-TERM MANAGEMENT ACTIONS 154 Chowilla Floodplain and Lindsay-Wallpolla Islands Icon Site Environmental Management Plan 2006-07 ii List of figures Figure 1: The Living Murray Icon Sites ................................................................................................................1 Figure 1.1: The Chowilla Floodplain and Lindsay-Wallpolla Islands Icon Site .....................................................5 Figure 4.1: The Chowilla floodplain boundary....................................................................................................16 Figure 4.2: Chowilla schematic – Chowilla anabranch system ..........................................................................18 Figure 4.3: Vegetation communities of the Chowilla floodplain..........................................................................21 Figure 6.1: Flood extent at 33,000 ML/day ........................................................................................................29 Figure 6.2: Flood extent at 62,000 ML/day Source: CSIRO, 2005.....................................................................30 Figure 6.3: Flood extent at 82,000 ML/day ........................................................................................................30 Figure 6.4: Flood extent at 100,000 ML/day ......................................................................................................31 Figure 6.5: Mechanisms that lead to the accession of saline groundwater to floodplain streams, following major floods ........................................................................................................................................................33 Figure 6.6: Groundwater movement before and after construction of Lock 6 ....................................................33 Source: Sharley and Huggan, 1995...................................................................................................................33 Figure 6.7: Sheep grazing exclusion map..........................................................................................................34 Figure 8.1: Example of desirable operating regime for Lock 5/6 weir pool manipulation ...................................44 Figure 8.2: Flow to South Australia, October 2000 – January 2001...................................................................45 Figure 8.3: Example operating conditions for Lake Victoria ...............................................................................46 Figure 9.1: Inundation coverage of the Chowilla floodplain at entitlement flows (5,000 ,ML/day) without an environmental regulator on the downstream section of Chowilla Creek....................................................57 Figure 9.2: Predicted inundation coverage of the Chowilla floodplain at entitlement flows (5,000 ML/day) with an environmental regulator on the downstream section of Chowilla Creek...............................................58 Figure 11.1: Conceptual adaptive management system flowchart.....................................................................68 Figure 12.1: Location of Lindsay, Mulcra and Wallpolla islands.........................................................................73 Figure 12.2: Maps for Lindsay, Mulcra and Wallpolla islands ............................................................................74 Figure 13.1: Percentage of total River Red Gum forest and Black Box woodland on Lindsay and Wallpolla islands inundated as a function of daily discharge in the River Murray .....................................................80 Figure 15.1: Groundwater elevation and salinity in the Channel Sands aquifer.................................................91 Figure 15.2: Interpreted extent of Coonambidgal Formation..............................................................................92 Figure 15.3: Interpreted thickness of clay (Blanchetown and Upper Parilla Formations) ...................................93 Figure 16.1: Location of proposed regulating structure at Webster’s Lagoon ....................................................95 Figure 16.2: Location of proposed regulating structure at Webster’s Lagoon ....................................................96 Figure 16.3: Location of proposed regulating structure at Horseshoe Lagoon...................................................97 Figure 16.4: Location of proposed regulating structure at Horseshoe Lagoon...................................................98 Figure 16.5: Location of proposed regulating structures at Lake Wallawalla ...................................................103