Climate Change, Sea Level Rise and Coastal Subsidence Along The
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Climate Change, Sea Level Rise and Coastal Subsidence along the Gippsland Coast: Implications for geomorphological features, natural values and physical assets Phase 2 - Gippsland Climate Change Study Woodside Beach 30% 40% Existing % occurance 2070 High Level % occurance 35% 2070 Mid Level % occurance 25% 2070 High Level % difference average 30% 2070 Mid Level difference average 25% 20% 20% 15% 15% 10% % Wave field 5% 10% % Change in average Hm0 0% -5% 5% -10% 0% -15% N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW Wave Direction N Calm 0.27 % Gippsland Coastal Board Final Report May 2008 Wave Height (m) Above 5 4 - 5 3 - 4 2 - 3 1 - 2 10 % Below 1 Climate Change, Sea Level Rise and Coastal Subsidence along the Gippsland Coast: Implications for geomorphological features, natural values and physical assets Phase 2 - Gippsland Climate Change Study Final Report Gippsland Coastal Board Gippsland Coastal Board 574 Main Street, PO BOX 483 BAIRNSDALE VIC 3875 Phone: (03) 5152 0451 Fax: (03) 5152 0444 E-mail: [email protected] Prepared for the Gippsland Coastal Board by: Eric Sjerp (Ethos NRM) Allan Charteris (Water Technology) May, 2008 Disclaimer This report is not to be used for purposes other than that for which it was intended. The conclusions, projections and modelling used in this report are based on the best available information at the time. Where this report is to be made available, either in part or in its entirety, to a third party, Ethos NRM and Water Technology reserve the right to review the information and documentation contained herein and update findings, conclusions and recommendations as required. ETHOS NRM WATER TECHNOLOGY ENVIRONMENTAL PLANNING & NATURAL WATER, COASTAL AND ENVIRONMENTAL CONSULTANTS RESOURCE MANAGEMENT CONSULTANTS PO Box 204, 162 Macleod St 15 Business Park Drive Bairnsdale, Vic. 387 Notting Hill, Vic. 3168 Telephone: 03-5153 0037 Telephone: 03-9558 9366 Facsimile: 03-5153 0038 Facsimile: 03-9558 9365 E-mail: [email protected] E-mail: [email protected] Website: www.ethosnrm.com.au Website: www.watech.com.au Specialist advice from: ENVIRONMENTAL GEOSURVEYS COASTAL GEOMORPHOLOGY SPECIALISTS Gippsland Coastal Board Page i Climate Change, Sea Level Rise and Coastal Subsidence along the Gippsland Coast: Implications for geomorphological features, natural values and physical assets Phase 2 - Gippsland Climate Change Study Final Report Gippsland Coastal Board TABLE OF CONTENTS EXECUTIVE SUMMARY ................................................................................................ 1 1 INTRODUCTION...................................................................................................... 8 1.1 BACKGROUND ..................................................................................................... 8 1.2 STUDY OBJECTIVE AND METHODOLOGY ................................................................ 8 1.3 PREVIOUS STUDIES AND REPORTS ....................................................................... 9 1.3.1 Climate Change Impacts and Adaptation in Gippsland Project...................11 1.4 ABOUT THE GIPPSLAND COASTAL BOARD...........................................................12 1.5 POLICY BASIS.....................................................................................................12 2 FEATURES OF THE GIPPSLAND COAST ............................................................14 2.1 NATURAL VALUES...............................................................................................14 2.2 MAJOR COASTAL TOWNS AND INFRASTRUCTURE..................................................15 3 CLIMATE CHANGE AND SEA LEVEL RISE..........................................................17 3.1 GLOBAL CLIMATE CHANGE..................................................................................17 3.2 CLIMATE CHANGE IN AUSTRALIA AND VICTORIA ....................................................19 3.3 GLOBAL AND AUSTRALIAN SEA LEVELS................................................................24 3.4 SUMMARY OF PHASE 1 GIPPSLAND CLIMATE CHANGE STUDY................................27 3.4.1 Stage 1 Report: The effect of climate change on coastal wind and weather patterns...................................................................................................................27 3.4.2 Stage 2 Report: The effect of climate change on storm surges ..................28 3.4.3 Stage 3 Report: The effect of climate change on extreme sea levels in Corner Inlet and the Gippsland Lakes .....................................................................30 4 COASTAL SUBSIDENCE.......................................................................................32 5 COASTAL GEOLOGY, EROSION POTENTIAL AND SEDIMENT TRANSPORT ..36 5.1 COASTAL GEOLOGY AND EROSION POTENTIAL .....................................................36 5.2 SEA LEVEL RISE AND COASTAL EROSION.............................................................38 5.3 WAVE MODELLING AND SEDIMENT TRANSPORT....................................................42 6 POTENTIAL IMPACTS AND THREATS TO THE GIPPSLAND COAST.................46 6.1 OVERVIEW OF POTENTIAL IMPACTS .....................................................................46 6.2 SAN REMO TO WILSON’S PROMONTORY...............................................................48 6.2.1 Coastal Erosion Potential ...........................................................................48 6.2.2 Coastal Erosion Threats - Environmental ...................................................48 6.2.3 Coastal Erosion Threats - Cultural..............................................................49 6.2.4 Coastal Erosion Threats – Infrastructure....................................................49 6.2.5 Vulnerable Sites .........................................................................................49 6.3 CORNER INLET AND NOORAMUNGA COAST...........................................................51 6.3.1 Coastal Erosion Potential ...........................................................................51 6.3.2 Coastal Erosion Threats - Environmental ...................................................51 6.3.3 Coastal Erosion Threats - Cultural..............................................................52 6.3.4 Coastal Erosion Threats – Infrastructure....................................................52 6.3.5 Vulnerable Sites .........................................................................................52 6.4 NINETY MILE BEACH AND GIPPSLAND LAKES........................................................54 6.4.1 Coastal Erosion Potential ...........................................................................54 6.4.2 Coastal Erosion Threats - Environmental ...................................................54 Gippsland Coastal Board Page ii Climate Change, Sea Level Rise and Coastal Subsidence along the Gippsland Coast: Implications for geomorphological features, natural values and physical assets Phase 2 - Gippsland Climate Change Study Final Report Gippsland Coastal Board 6.4.3 Coastal Erosion Threats - Cultural..............................................................55 6.4.4 Coastal Erosion Threats – Infrastructure....................................................55 6.4.5 Vulnerable Sites .........................................................................................55 6.5 LAKES TYERS TO NSW BORDER .........................................................................59 6.5.1 Coastal Erosion Potential ...........................................................................59 6.5.2 Coastal Erosion Threats - Environmental ...................................................59 6.5.3 Coastal Erosion Threats - Cultural..............................................................59 6.5.4 Coastal Erosion Threats – Infrastructure....................................................59 6.5.5 Vulnerable Sites .........................................................................................59 7 ADAPTIVE MANAGEMENT FOR SEA LEVEL RISE AND CLIMATE CHANGE ALONG THE GIPPSLAND COAST...............................................................................62 7.1 ADAPTIVE MANAGEMENT.....................................................................................62 7.2 PRO-ACTIVE RESPONSE TO CLIMATE CHANGE THREATS .......................................62 7.2.1 Awareness Raising.....................................................................................62 7.2.2 Future Planning..........................................................................................63 7.3 RE-ACTIVE RESPONSE TO CLIMATE CHANGE THREATS .........................................64 7.3.1 Do Nothing .................................................................................................64 7.3.2 Planned Retreat .........................................................................................65 7.3.3 Adaptation..................................................................................................65 7.3.4 Protection...................................................................................................66 7.4 RISK MANAGEMENT ............................................................................................67 8 RECOMMENDATIONS FOR FUTURE WORK .......................................................69 8.1 IMPROVED CLIMATE CHANGE AND SEA LEVEL RISE MODELS .................................69 8.2 GEOLOGICAL SURVEY.........................................................................................69