APPENDIX C Lake Macdonald Water Lowering – Adaptive Management Plan Table of Contents Table of Contents C.1 INTRODUCTION ....................................................................................................................................................... 1 C.1.1 Background .................................................................................................................................................. 1 C.1.2 Site Description ............................................................................................................................................ 1 C.1.3 Purpose and Objectives ................................................................................................................................ 1 C.2 LOWERING LAKE MACDONALD ............................................................................................................................... 3 C.2.1 Water Quantity ............................................................................................................................................ 3 C.2.2 Drawdown Method ...................................................................................................................................... 3 C.2.3 Discharge Location ....................................................................................................................................... 5 C.2.4 Maintenance of Water Level Following Drawdown ..................................................................................... 5 C.3 WATER QUALITY ...................................................................................................................................................... 6 C.3.1 Water Quality in Lake Macdonald ................................................................................................................ 6 C.3.2 Potential Impacts of Lowering Lake Macdonald .......................................................................................... 6 C.3.3 Management Measures ............................................................................................................................... 7 C.4 EROSION AND SEDIMENT CONTROL ....................................................................................................................... 9 C.4.1 Sediment in Lake Macdonald ....................................................................................................................... 9 C.4.2 Potential Impacts of Lowering Lake Macdonald .......................................................................................... 9 C.4.3 Management Measures ............................................................................................................................... 9 C.5 AQUATIC FLORA AND FAUNA ................................................................................................................................ 11 C.5.1 Flora and Fauna in Lake Macdonald and Six Mile Creek ............................................................................ 11 C.5.2 Matters of National and State Environmental Significance ....................................................................... 12 C.5.3 Potential Impacts of Lowering Lake Macdonald ........................................................................................ 13 C.5.4 Management Measures ............................................................................................................................. 14 C.6 AQUATIC FAUNA SALVAGE AND RELOCATION ...................................................................................................... 16 C.6.1 Purpose ...................................................................................................................................................... 16 C.6.2 Baseline Surveys ......................................................................................................................................... 16 C.6.3 Salvage and Relocation Targets.................................................................................................................. 17 C.6.4 Relocation Sites .......................................................................................................................................... 17 C.6.5 Schedule and Resourcing ........................................................................................................................... 18 C.6.6 Capture Methods ....................................................................................................................................... 20 C.6.7 Holding and Transport Methods ................................................................................................................ 20 C.6.8 Monitoring ................................................................................................................................................. 21 C.7 BIOSECURITY.......................................................................................................................................................... 22 C.7.1 Biosecurity Matter in Lake Macdonald ...................................................................................................... 22 C.7.2 Potential Impacts of Lowering Lake Macdonald ........................................................................................ 22 C.7.3 Management Measures ............................................................................................................................. 23 C.8 INCIDENT AND CONTINGENCY PLANNING ............................................................................................................ 25 C.8.1 Lowering of Lake Macdonald ..................................................................................................................... 25 C.8.2 Aquatic Fauna Relocation........................................................................................................................... 25 C.8.3 During the Construction Period ................................................................................................................. 26 C.9 COMMUNITY INVOLVEMENT ................................................................................................................................ 28 C.10 REHABILITATION OF LAKE MACDONALD ............................................................................................................... 29 C.10.1 Aquatic Habitat .......................................................................................................................................... 29 C.10.2 Aquatic Fauna ............................................................................................................................................. 29 C.10.3 Water Quality ............................................................................................................................................. 29 C.10.4 Removal of Project Infrastructure .............................................................................................................. 29 C.11 PERMITS AND QUALIFICATIONS ............................................................................................................................ 30 C.11.1 Permits and Approvals ............................................................................................................................... 30 C.11.2 Qualifications ............................................................................................................................................. 30 LAKE MACDONALD WATER LOWERING – ADAPTIVE MANAGEMENT PLAN Seqwater Six Mile Creek Dam Safety Upgrade Project 25 January 2019 C-iii Table of Contents C.12 REFERENCES .......................................................................................................................................................... 31 Appendices BACKGROUND INFORMATION – WATER QUALITY BACKGROUND INFORMATION – AQUATIC FLORA AND FAUNA List of Tables Table C.2-1: Proposed Lake Macdonald dewatering plan. ................................................................................................. 4 Table C.3-1: Management of water quality during the lowering of Lake Macdonald ........................................................ 7 Table C.4-1: Management of erosion and sediment during the lowering of Lake Macdonald ........................................ 10 Table C.5-1 Species listed under the NCA and EPBC ......................................................................................................... 12 Table C.5-2: Management of aquatic flora and fauna during the lowering of Lake Macdonald ...................................... 14 Table C.6-1: Initial dewatering aquatic fauna salvage schedule ....................................................................................... 19 Table C.7-1: Management of pest animal biosecurity matters during the lowering of Lake Macdonald ........................ 23 Table C.7-2: Management of pest plant biosecurity matters during the lowering of Lake Macdonald ........................... 24 Table C.12-1:Water Quality Objectives for Protection of Aquatic Ecosystems in lowland waters of the Mary River Basin. .......................................................................................................................................................................................... 33 List of Figures Figure C.1-1: Lake Macdonald location and Project area ..................................................................................................