Environmental Flow Determination for the Maribyrnong River Final Recommendations Revision C July 2006 Environmental Flow Determination for the Maribyrnong River –Final Recommendations Environmental Flow Determination for the Maribyrnong River FINAL RECOMMENDATIONS L:\work\NRG\PROJECTS\2005\034 Maribyrnong E-flows\02\03 Recommendations Paper\Recommendations RevC.doc Document History: ISSUE REVISION AUTHOR CHECKED APPROVED DESCRIPTION DATE NUMBER Preliminary Draft 30.11.2005 A A Wealands C Arnott C Arnott for Comment Final Draft for 18.01.2006 B A Wealands C Arnott C Arnott Comment Inclusion of 31.01.2006 B1 A Wealands C Arnott C Arnott estuary recommendations 18.07.2006 C A Wealands C Arnott C Arnott Final Report Natural Resources Group Earth Tech Engineering Pty Ltd ABN 61 089 482 888 Head Office 71 Queens Road Melbourne VIC 3004 Tel +61 3 8517 9200 Environmental Flow Determination for the Maribyrnong River –Final Recommendations Contents Contents .................................................................................................................. i Tables....................................................................................................................... i 1 Introduction ................................................................................................... 4 Outline of this Report.............................................................................................5 The Maribyrnong River Catchment .......................................................................6 2 Environmental Flow Analysis....................................................................... 7 2.1 Surveys of selected reaches ........................................................................7 2.2 Hydraulic and Hydrologic Modelling ...........................................................7 2.2.1 Representativeness of the Model .......................................................................... 9 2.2.2 Hydraulic Model Sensitivity Assessment and Analysis ........................................ 10 2.3 Rates of Rise and Fall.................................................................................12 3 Reach Recommendations........................................................................... 13 4 Estuary Recommendations ........................................................................ 61 5 Supporting Recommendations .................................................................. 66 6 Conclusion .................................................................................................. 67 7 References................................................................................................... 68 Tables Table 2-1 Upper and lower error limits for a 25% change in boundary conditions at the same water elevation for the recommended low flow and bankfull flow. ....11 Table 2-2 Recommended maximum rates of rise and fall (expressed as a percentage of the previous days flow) for all reaches of the Maribyrnong River catchment. ......................................................................................................12 Table 3-1 Flow Processes and Flow Components for Reach One – Deep Creek Upper Catchment ............................................................................................15 Table 3-2. Flow Recommendations for Reach One – Deep Creek Upper Catchment ........................................................................................................................18 Table 3-3 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach One....................................................................................18 Table 3-4 Flow Processes and Flow Components for Reach Two – Deep Creek Mid Catchment.......................................................................................................20 Table 3-5. Flow Recommendations for Reach Two – Deep Creek Mid Catchment 23 Table 3-6 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach Two ....................................................................................23 Page i Recommendations RevC.doc July 2006 Rev C Environmental Flow Determination for the Maribyrnong River –Final Recommendations Table 3-7 Flow Processes and Flow Components for Reach Three – Emu Creek.25 Table 3-8. Flow Recommendations for Reach Three – Emu Creek .......................27 Table 3-9 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach Three .................................................................................27 Table 3-10 Flow Processes and Flow Components for Reach 4 – Deep Creek Lower Catchment ............................................................................................29 Table 3-11. Flow Recommendations for Reach Four – Deep Creek Lower Catchment.......................................................................................................32 Table 3-12 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach Four ...................................................................................32 Table 3-13 Flow Processes and Flow Components for Reach 5 – Riddells Creek.35 Table 3-14. Flow Recommendations for Reach Five – Riddells Creek ..................38 Table 3-15 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach Five....................................................................................39 Table 3-16 Flow Processes and Flow Components for Reach Six – Jacksons Creek Upper Catchment ............................................................................................41 Table 3-17. Flow Recommendations for Reach Six – Jacksons Creek Upper Catchment.......................................................................................................44 Table 3-18 Comparison of Flow Recommendations to Current Flow Regime – Reach Six........................................................................................................46 Table 3-19 Flow Processes and Flow Components for Reach 7 – Jacksons Creek Lower Catchment ............................................................................................49 Table 3-20. Flow Recommendations for Reach Seven – Jacksons Creek Lower Catchment.......................................................................................................52 Table 3-21 Comparison of Flow Recommendations to Current Flow Regime – Reach Seven...................................................................................................53 Table 3-22 Flow Processes and Flow Components for Reach 8 – Maribyrnong River Freshwater Reach..................................................................................56 Table 3-23. Flow Recommendations for Reach Eight – Maribyrnong River Freshwater Reach...........................................................................................59 Table 3-24 Comparison of Flow Recommendations to Current and Natural Flow Regimes – Reach Eight...................................................................................60 Please cite this document as: Earth Tech (2006) Environmental Flow Determination for the Maribyrnong – Draft Final Recommendations Paper . Unpublished Report to Melbourne Water Corporation by the Maribyrnong River Environmental Water Requirements Technical Panel. Page ii Recommendations RevC.doc July 2006 Rev C Environmental Flow Determination for the Maribyrnong River –Final Recommendations Acknowledgements: The Maribyrnong River Environmental Water Requirements Technical Panel (the Technical Panel) consists of (in alphabetical order, with fields of expertise): Michael Aberton Riparian vegetation Chris Arnott Chair of the technical panel Tim Doeg Macroinvertebrate ecology and Fish Brian Finlayson Geomorphology Jeremy Hindell Estuarine processes Geoff Vietz Hydrology and Hydraulic modelling The Earth Tech project management team consists of: Chris Arnott Project Manager Amanda Wealands Project Support The Technical Panel wishes to acknowledge the assistance of Christine Hughes (MW) and the Steering Committee and Advisory Group for their assistance in this phase of the project. The Steering Committee for the project consisted of: Jamie Ewert Melbourne Water Corporation Paul Louws Western Water Phil Mitchell Department of Sustainability and the Environment Cameron Welsh Southern Rural Water The Advisory Group consisted of: Arnie Azaris Sunbury Conservation Society Wade Bland Hume City Council David Blicblau Deep Creek Landcare Christina Cheers Friends of Emu Bottom Reserve Garrett Hall EPA Gary Lawes MW Diverter Lachlan Milne Shire of Macedon Ranges Bill Mole SRW Diverter John Robinson Port Phillip and Westernport Catchment Management Authority Chris Ryan SRW Diverter Leon Stackpole EPA Fiona Stevens Department of Sustainability and the Environment (Coast Action Coast Care) Ian Sutherland Friends of Emu Bottom Reserve Ian Taylor Sunbury Landcare Zoe Thomson Brimbank City Council Eddie Tsyrlin Melbourne Water Page i Recommendations RevC.doc July 2006 Rev C Environmental Flow Determination for the Maribyrnong River –Final Recommendations Acronyms/Abbreviations used in this report: CRC Co-operative Research Centre DSE Department of Sustainability and Environment EVC Ecological Vegetation Class EWR Environmental Water Requirements FLOWS The “Statewide Method for Determining Environmental Water Requirements” IFU Internal Floodplain Unit LWD Large Woody Debris MW Melbourne Water Corporation Technical