FINAL REPORT: Georges River Coastal Management Program Scoping Study December 2020 Document history Revision: Revision no. 02 Author/s M. Rosenthal M. Sano Checked M. Sano E. Zavadil Approved E. Zavadil Distribution: Revision no. 01a Issue date 18 May 2020 Issued to Peter Ryan (Georges Riverkeeper) Description: Draft for comment Revision no. 02 Issue date 4 December 2020 Issued to Peter Ryan (Georges Riverkeeper) Description: Final Report Citation: Please cite as: Alluvium (2020). Georges River Coastal Management Program Scoping Study. Report by Alluvium for Georges Riverkeeper. December 2020. Acknowledgement: Alluvium acknowledges the Traditional Owners and custodians of the lands on which we work. The sites assessed are on the lands of the Dharug and Dharawal People, and we acknowledge them as Traditional Owners. We pay our respects to their elders, and the elders of all Aboriginal and Torres Strait Islander Peoples, past, present, and into the future. Contents 1 Introduction 1 1.1 Scoping study purpose 1 1.2 Study area 1 1.3 Report structure 6 2 Program context 7 2.1 NSW Coastal Management Framework 7 2.2 Coastal Management Programs 8 3 Strategic context 11 3.1 Physical setting 12 3.1.1 Landscape context, geology and soils 12 3.1.2 Coastal processes, sediment supply and transport 14 3.1.3 Coastal hazards 17 3.1.4 Shoreline management 20 3.2 Hydrology and hydrodynamics 24 3.2.1 Catchment hydrology 24 3.2.2 Groundwater 24 3.2.3 Hydrodynamics 25 3.2.4 Tides 26 3.2.5 Flooding 26 3.3 Climate 27 3.3.1 Current climate 27 3.3.2 Past observations 27 3.3.3 Future projections 28 3.3.4 Sea level rise 29 3.4 Ecological value 32 3.4.1 Terrestrial vegetation 33 3.4.2 Seagrass meadows 33 3.4.3 Mangroves, saltmarshes and reedlands 34 3.4.4 Upper catchment freshwater ecosystems 34 3.4.5 Fauna 35 3.4.6 Threatened Ecological Communities 35 3.4.7 Invasive species 37 3.4.8 Environmental pressures 37 3.4.9 Towra Point Nature Reserve 37 3.5 Built urban environment 39 3.5.1 Imperviousness 39 3.5.2 Planning and development 40 3.5.3 Residential density 40 3.5.4 Industrial density 40 3.5.5 Designated growth areas within the catchment 41 3.6 Society, culture, and heritage 43 3.6.1 Cultural diversity 43 3.6.2 Indigenous heritage 43 3.6.3 Early British Australian heritage 43 3.6.4 Population 44 3.7 Economy 45 3.7.1 Economic sectors 45 3.7.2 Ecosystem services 46 Georges River Coastal Management Program Scoping Study - 2020 iii 3.7.3 Recreational use 46 3.7.4 Primary production 46 3.7.5 Regional socio-economic summary 47 3.7.6 Economic considerations for CMP development 47 3.8 Legal framework 48 3.8.1 Acts of Parliament 48 3.8.2 State Environmental Planning Policies 48 3.8.3 Governance 50 3.9 Urban and regional planning 52 3.9.1 State level plans 52 3.9.2 Regional plans 52 3.9.3 Local plans 53 3.9.4 Development application process 55 3.9.5 LEP and LSPS reviews 55 3.10 Natural resource management 57 3.10.1 Georges Riverkeeper Strategic Plan (2018) 57 3.10.2 Metropolitan water management 58 3.10.3 Groundwater management 59 3.10.4 Crown land and National Parks 60 4 Review of key coastal management arrangements 64 4.1 Botany Bay Water Quality Improvement Plan (2011) 64 4.2 Georges River Estuary Coastal Zone Management Plan (2013) 68 4.3 Towra Point PoM, Formal Assessment of Change in Ecological Character and Response Strategy 72 5 CMP Stakeholder and community engagement context 74 5.1 Stakeholder and Community Engagement Strategy 74 5.2 Engagement activities during the Scoping Study 74 5.3 Incorporating contributions from stakeholder engagement into the Scoping Study 74 5.4 Response to COVID-19 75 6 Determine the scope of the CMP 76 6.1 Purpose, vision and objectives 76 6.2 Geographical extent of Georges River CMP 76 6.3 Alignment with Coastal Management Areas 77 6.3.1 Coastal Wetlands and Littoral Rainforest Area 77 6.3.2 Coastal Vulnerability Area 77 6.3.3 Coastal Environment Area 77 6.3.4 Coastal Use Area 78 6.4 Synthesis of values 82 6.4.1 Lower Georges River Estuary and Botany Bay 82 6.4.2 Upper Catchment 82 6.4.3 Values identified during the stakeholder engagement workshop 83 6.4.4 Summary list of key values underpinning the Coastal Management Program 84 6.5 Synthesis of issues 85 6.5.1 Issues identified in the CZMP 85 6.5.2 Relevant threats identified in the MEMA TARA 85 6.5.3 Issues identified in the BBWQIP 86 6.5.4 Issues identified during the stakeholder engagement workshop 86 6.5.5 Summary list of priority issues to consider in the Coastal Management Program 86 6.6 First pass risk assessment 87 6.6.1 First pass risk assessment for environmental values 89 Georges River Coastal Management Program Scoping Study - 2020 iv 6.6.2 First pass risk assessment for social values 90 6.6.3 First pass risk assessment for economic values 91 6.7 Prioritised list of issues to be addressed by the Coastal Management Program 92 7 Knowledge gaps: determine where action is required 93 7.1 Overview 93 7.2 Knowledge gaps related to identified values, issues, and risks 93 7.3 Knowledge gaps addressed by the Marine Estate Management Strategy (MEMS) 100 8 Preliminary business case 101 8.1 Environmental and social considerations 101 8.2 Economic considerations 101 8.2.1 Preliminary damage / loss assessment 102 8.2.2 Tourism 102 8.2.3 Case study consideration: Brighton Le Sands Beach 103 8.2.4 Case study consideration: Urban stream amenity value 103 8.3 Risks of preparing/not preparing a CMP 104 8.3.1 Statutory obligations 104 8.3.2 Delaying/avoiding action will incur significant future cost 105 8.3.3 Risks of preparing a CMP 105 8.4 Funding and cost sharing opportunities 105 8.4.1 Coasts & Estuaries Grant and alignment with MEMS 105 8.4.2 Alignment with other grants and programs 106 8.4.3 Sharing cost with other CMPs for certain studies 106 9 Forward plan 108 9.1 Governance options for the CMP preparation and implementation 108 9.1.1 Individual CMPs for each Council LGA 108 9.1.2 Georges River catchment wide CMP 109 9.1.3 Whole of Botany Bay CMP 109 9.1.4 Recommended approach 109 9.2 Proposed components for each Stage of CMP forward plan 110 9.3 Consideration of fast tracking 113 9.4 Stakeholder review and endorsement 113 10 References 114 Appendix A –Stakeholder and Community Engagement Strategy 118 Appendix B – Stakeholder study tour and workshop 153 Appendix C – Overview of CZMP implementation to date 173 Appendix D – First pass risk assessment details 245 Appendix E – Overview of information gathering survey responses 250 Appendix F – RCAT analysis 270 Appendix G – Economic analysis 280 Appendix H – Additional relevant legislation 288 Appendix I –Planning documentation for Member Councils 292 Georges River Coastal Management Program Scoping Study - 2020 v Figures Figure 1. A map of the study area including LGA boundaries across the Georges River catchment 2 Figure 2. The Georges River catchment divided into sub-catchments corresponding with Georges Riverkeeper water quality report cards 4 Figure 3. The study area contains stretches of sandy coastline which have experienced past shoreline stability issues 5 Figure 4. An overview of the changes that have occurred to legislation, policies and guiding material involved in NSW coastal management reform 7 Figure 5. Summary of several key documents/programs that influence the CMP process 8 Figure 6. Five stages to preparing a CMP (OEH 2018) 8 Figure 7. Acid sulphate soil risk within the Georges River catchment (NSW DPE 2013) 13 Figure 8. Conceptual model of coastal processes and natural assets along the Botany Bay shoreline (modified from BMT WBM 2003) 15 Figure 9. Sediment transport pathways along Lady Robinsons Beach (modified from Advisian 2016) 16 Figure 10. Satellite imagery of the series of groynes along Silver Beach installed to manage a westward longshore sediment transport in southern Botany Bay 21 Figure 11. Comparison of sediment accumulation at groynes to the south (left) and north (right) of Lady Robinsons Beach. Build-up of sediment along groynes demonstrates the prevailing direction of sediment transport 22 Figure 12. Towra Point was the site of beach nourishment works in 2003 with approximately 60,000 m 3 of sand from the spit relocated to the receding shoreline (Google 2020) 22 Figure 13. Ramsgate baths beach restoration is occurring in 2019 (image below) with 28,000 m 3 of sand from the spit formed near the Georges River 16ft Sailing Club at Sandringham. Bayside Council, 2019 23 Figure 14. A temporary installation of geobags is installed to protect heritage items including Norfolk Island Pines in Kamay Botany Bay National Park 23 Figure 15. Highest, lowest and mean monthly rainfall from 1968 to 2019 at Bankstown Airport (BOM 2019) 27 Figure 16. Modelled inundation scenarios (2100 +0.74m at highest tide) from a simple bathtub model provide an indication of the areas at risk within the Georges River catchment (Coastal Risk 2017) 29 Figure 17. Zones within the study area (circled) which face varying degrees of risk to shoreline recession (OEH 2017) 30 Figure 18.