SEA LEVEL RISE, GREEN INFRASTRUCTURE AND RESILIENCE ALONG THE EXTANT BRUNSWICK-ALTAMAHA CANAL by LISA EMILY BIDDLE (Under the Direction of Jon Calabria) ABSTRACT Recent projections of sea level rise indicate that global mean sea levels could rise up to 2.0 meters (6.6 feet) by the end of this century. Coastal communities need to respond with innovative design strategies to adapt to uncertain changes in water levels and precipitation. This research-design thesis identifies green infrastructure as an adaptable design strategy that could enhance the resilience of coastal communities to adapt to sea level rise and increased flooding risk. This thesis suggests green infrastructure to attain these objectives, yet realizes limitations to its application in coastal protection. Green infrastructure is applied in a site design that specifically addresses sea level rise on the extant Brunswick-Altamaha Canal in Glynn County, GA. INDEX WORDS: Sea level rise, green infrastructure, Brunswick-Altamaha Canal, Glynn County, adaptation, soft coastal protection, landscape architecture, design SEA LEVEL RISE, GREEN INFRASTRUCTURE AND RESILIENCE ALONG THE EXTANT BRUNSWICK-ALTAMAHA CANAL by LISA EMILY BIDDLE BA, Dickinson College, 2008 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF LANDSCAPE ARCHITECTURE ATHENS, GEORGIA 2013 © 2013 Lisa Emily Biddle All Rights Reserved SEA LEVEL RISE, GREEN INFRASTRUCTURE AND RESILIENCE ALONG THE EXTANT BRUNSWICK-ALTAMAHA CANAL by LISA EMILY BIDDLE Major Professor: Jon Calabria Committee: Doug Pardue Rosanna Rivero Jason Evans Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May 2013 iv ACKNOWLEDGEMENTS This thesis would not have been possible without the help of many people and organizations. First, I would like to recognize my major professor, Jon Calabria, for his guidance and encouragement in working toward this thesis. I would also like to thank my reading committee, Doug Pardue, Rosanna Rivero, and Jason Evans for their time and expertise, as well as their dedication to studying issues of climate change. This thesis could not have been completed without the generous support of a graduate assistantship through the Office of the Vice President's Public Service and Outreach (PSO) Graduate Assistantship Program and the Carl Vinson Institute of Government. A special thank you to David Hainley for his time spent introducing me to the Brunswick-Altamaha Canal. I also owe tremendous gratitude to the CED faculty and staff who have inspired and guided me through this degree. To my classmates – your humor, generosity, and friendship over the past three years has meant the world to me. And last, but certainly not least, I must thank my parents for their immense support throughout the years. v TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ........................................................................................................... iv LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1 INTRODUCTION .........................................................................................................1 Research Objectives .................................................................................................3 Methodology and Thesis Structure ..........................................................................4 2 SEA LEVEL RISE PROJECTIONS AND COASTAL ADAPTATION STRATEGIES................................................................................................................7 Global Sea Level Rise Projections ..........................................................................8 Storm Events ..........................................................................................................10 Impacts of Sea Level Rise and Storm Events ........................................................12 Sea Level Rise on the Georgia Coast .....................................................................14 Adaptation Approaches for Sea Level Rise ...........................................................19 Discussion: Diverse Approaches to Coastal Adaptation Planning ........................23 Conclusion .............................................................................................................24 3 GREEN INFRASTRUCTURE AS A RESILIENT SEA LEVEL RISE ADAPTATION STRATEGY ............................................................................................26 Green Infrastructure Defined .................................................................................27 vi Green Infrastructure as a Climate Change Adaptation Strategy ............................30 Benefits of Green Infrastructure Approach ............................................................31 Limitations of Green Infrastructure Approach ......................................................48 Design Precedents ..................................................................................................51 Conclusion .............................................................................................................62 4 THE BRUNSWICK-ALTAMAHA CANAL & FEASIBILITY OF ITS REUTILIZATION .............................................................................................................64 History of Brunswick-Altamaha Canal ..................................................................65 Present Condition of the Canal ..............................................................................69 Proposed Reutilization of the Canal ......................................................................74 Reutilization Planning and Sea Level Rise ............................................................77 Conclusion .............................................................................................................84 5 DESIGN APPLICATION ............................................................................................86 Site Selection .........................................................................................................86 Design Process and Site Inventory ........................................................................88 Site Design .............................................................................................................90 Design Discussion ..................................................................................................94 6 CONCLUSION ..........................................................................................................111 REFERENCES ............................................................................................................................114 APPENDICES A BRUNSWICK-ALTAMAHA CANAL CONNECTIVITY STUDY .............................126 B BRUNSWICK-ALTAMAHA CANAL VEGETATION STUDY ..................................137 vii LIST OF TABLES Page Table 1: Sea Level Rise Impacts ....................................................................................................12 Table 2: Comparison of hard and soft structural option for coastal protection .............................21 Table 3: Green infrastructure types ................................................................................................30 Table 4: Green infrastructure benefits classified using the triple bottom line ...............................32 Table 5: Green infrastructure benefits classified using the Landscape Architecture Foundation .33 Table 6: Classification of green infrastructure practices in the MOMA Rising Currents .............53 Table 7: Case study comparison chart ...........................................................................................62 viii LIST OF FIGURES Page Figure 1: Thesis Structure Diagram .................................................................................................6 Figure 2: Sea level rise scenarios produced for the U.S. National Climate Assessment .................9 Figure 3: Impacts of a 0.5m or 1.0m sea level rise on coastal flood frequency ............................11 Figure 4: Sea level rise trends based on tidal gauge data ..............................................................15 Figure 5: The shape of Georgia’s coastline and hurricane tracks ..................................................17 Figure 6: Storm surge inundation map for Glynn County, GA .....................................................19 Figure 7: Diagram of coastal adaptation responses to sea level rise ..............................................20 Figure 8: A conceptual comparison of CSO capture over time for green infrastructure ...............37 Figure 9: Morphologies of tidal wetlands and corresponding habitats ..........................................38 Figure 10: The process of coastal squeeze .....................................................................................40 Figure 11: Visualizations of sea level rise and adaptation scenarios in British Columbia ............45 Figure 12: Storm surge signage examples .....................................................................................46 Figure 13: ARO and dlandstudio’s “New Urban Ground” ............................................................55 Figure 14: “Topographical Shifts” poster, Rising Tides Competition ...........................................57 Figure 15: The RAYDike, Rising Tides Competition ...................................................................58 Figure 16: The Picnic Sea Spot ......................................................................................................60 Figure 17: Location map of Brunswick-Altamaha Canal in Glynn County, GA ..........................65 Figure 18: Early 19th century trade routes between Central Georgia and the Georgia Coast ........66 Figure 19: General canal dimensions as designed .........................................................................67 ix Figure 20: The original routing plan and profiles produced by the engineer ................................67 Figure 21: Impacts of railroad on commerce flow .........................................................................68 Figure 22: Beaver dams along the Brunswick-Altamaha Canal north of Harry Driggers Blvd ....70 Figure 23: The Brunswick-Altamaha Canal towpath looking south from Hwy 99 .......................71 Figure 24: The Brunswick-Altamaha Canal at Harry Driggers Blvd looking north ......................71 Figure 25: The Brunswick-Altamaha Canal towpath at Harry Driggers Blvd ..............................72 Figure 26: The Brunswick-Altamaha Canal at Glynco Parkway looking north ............................72 Figure 27: The Brunswick-Altamaha Canal at Old Jesup Rd bridge looking north ......................73 Figure 28: Sea level at current MHHW and with a 6’ rise ............................................................79 Figure 29: Zoomed view, sea level at current MHHW and with a 6’ rise .....................................81 Figure 30: SLAMM output showing vegetation changes ..............................................................83 Figure 31: Site location maps ........................................................................................................97 Figure 32: Site photos ....................................................................................................................98 Figure 33: Existing site conditions and site inventory ...................................................................99 Figure 34: Sea level rise inventory maps .....................................................................................100 Figure 35: Site concept plan ........................................................................................................101 Figure 36: Diagram of applied adaptation strategies ...................................................................102 Figure 37: Site Plan – current mean sea level ..............................................................................103 Figure 38: Site Plan – 6 foot sea level rise ...................................................................................104 Figure 39: Site sections ................................................................................................................105 Figure 40: Diagrams of path types ...............................................................................................106 Figure 41: Diagrams of swale function ........................................................................................107 Figure 42: Vignette of bioswales and multi-use path ..................................................................108