Impacts of Climate Change and Variability on Transportation Systems and Infrastructure: The Gulf Coast Study, Phase 2 Task 3.2: Engineering Assessments of Climate Change Impacts and Adaptation Measures U.S. Department of Transportation August 2014 Gulf Coast Study, Phase 2 FHWA-HEP-15-004 Gulf Coast Study, Phase 2—Task 3.2: Engineering Analysis and Assessment Impacts of Climate Change and Variability on Transportation Systems and Infrastructure The Gulf Coast Study, Phase 2 Engineering Analysis and Assessment Final Report, Task 3.2 Prepared for: The USDOT Center for Climate Change and Environmental Forecasting Project managed by: Office of Planning, Environment, and Realty Federal Highway Administration, USDOT Robert Hyman, Robert Kafalenos, Brian Beucler Prepared by: Parsons Brinckerhoff and ICF International With contributions from South Coast Engineers Date: August 2014 Contract No.: GS-10F-0124J Report No.: FHWA-HEP-15-004 U.S. Department of Transportation i August 2014 Gulf Coast Study, Phase 2—Task 3.2: Engineering Analysis and Assessment Acknowledgements The authors gratefully acknowledge the assistance from the following: The Mobile Metropolitan Planning Organization’s Climate Change Work Group The U.S. Department of Transportation’s Gulf Coast Phase 2 Technical Advisory Committee Local Experts on Highways: Kevin Harrison and Tom Piper of the South Alabama Regional Planning Commission; Lee Reach, Don Powell, David Ramsey of the Alabama Department of Transportation; Ricky Mitchell and Tina Sanchez, Mobile County; Nick Amberger of the City of Mobile Local Experts on Ports: Jerald Kichler We also gratefully acknowledge the time and effort provided by the peer reviewers of this report (in alphabetical order): Eric Brown, Federal Highway Administration (FHWA); Gary Carr, Federal Railroad Administration; Andrea Hendrickson, Minnesota Department of Transportation; Casey Kramer, Washington State Department of Transportation; Jeffrey Knaub, Maryland State Highway Administration (MDSHA); Khalid Mohammed, FHWA; Cynthia Nurmi, FHWA; Karuna Pujara, MDSHA; and Laurel Radow, FHWA. Principal Authors and Reviewers (in alphabetical order) John Baesch, Tiffany Batac, Glenn Bottomley, Chris Dorney, Mary Erchul, Everett Gupton, Jake Keller, Robert Kinghorn, Justin Lennon, Benny Louie, Gary McVoy, Michael Meyer, Jerry Ramsden, Robert Snyder, Victor Sokol, and Stefany Wang of Parsons Brinckerhoff Anne Choate and Beth Rodehorst of ICF International Brian Beucler, Rob Hyman, and Rob Kafalenos of the Federal Highway Administration (FHWA) Other Contributing Authors (in alphabetical order) Michael Flood and Ismail Karatas of Parsons Brinckerhoff Susan Asam, Brenda Dix, Katy Maher, Mike Savonis, and Cassandra Snow of ICF International Scott Douglass and Bret Webb of South Coast Engineers Cover photo credits, clockwise from top left: Parsons Brinckerhoff U.S. Department of Transportation ii August 2014 Gulf Coast Study, Phase 2—Task 3.2: Engineering Analysis and Assessment Contents 1. Executive Summary ...................................................................................................................1 1.2 Overview of the General Process for Transportation Facility Adaptation Assessments ...................................................................................................................2 1.3 Overview of Case Studies Selected to Demonstrate the Process ........................................3 1.4 Key Lessons Learned ...........................................................................................................6 2. Background ..............................................................................................................................15 2.1 Overview of Gulf Coast Project .........................................................................................15 2.2 Purpose of the Engineering Assessments ..........................................................................19 2.3 Report Roadmap ................................................................................................................20 3. A General Process for Transportation Facility Adaptation Assessments ..........................22 3.1 Overview ............................................................................................................................22 3.2 The Process ........................................................................................................................24 3.2.1 Step 1 – Describe the Site Context ........................................................................................ 24 3.2.2 Step 2 – Describe the Existing / Proposed Facility............................................................... 24 3.2.3 Step 3 – Identify Climate Stressors that May Impact Infrastructure Components................ 25 3.2.4 Step 4 – Decide on Climate Scenarios and Determine the Magnitude of Changes .............. 25 3.2.5 Step 5 – Assess Performance of the Existing / Proposed Facility ......................................... 27 3.2.6 Step 6 – Identify Adaptation Option(s) ................................................................................. 29 3.2.7 Step 7 – Assess Performance of the Adaptation Option(s) ................................................... 30 3.2.8 Step 8 – Conduct an Economic Analysis ............................................................................... 30 3.2.9 Step 9 – Evaluate Additional Decision-Making Considerations ........................................... 31 3.2.10 Step 10 – Select a Course of Action .................................................................................... 32 3.2.11 Step 11 – Plan and Conduct Ongoing Activities ................................................................. 32 4. Case Studies ..............................................................................................................................33 4.1 Introduction ........................................................................................................................33 4.2 Selection of Cases ..............................................................................................................33 4.3 Approach ............................................................................................................................33 4.4 Individual Case Studies......................................................................................................37 4.4.1 Culvert Exposure to Precipitation Changes – The Airport Boulevard Culvert over Montlimar Creek .................................................................................................................. 37 4.4.2 Bridge Over Navigable Waterway Exposure to Sea Level Rise – The Cochrane- Africatown USA Bridge ........................................................................................................ 89 4.4.3 Bridge Approach Embankment Exposure to Sea Level Rise – US 90/98 Tensaw- Spanish River Bridge (Western Approach) ........................................................................ 102 4.4.4 Bridge Abutment Exposure to Storm Surge – US 90/98 Tensaw-Spanish River Bridge (Western Abutment) ................................................................................................ 126 4.4.5 Bridge Segment Exposure to Storm Surge – The US 90/98 Ramp to I-10 Eastbound at Exit 30 ............................................................................................................................ 158 4.4.6 Road Alignment Exposure to Storm Surge – I-10 (Mileposts 24 to 25) .............................. 187 4.4.7 Coastal Tunnel Exposure to Storm Surge – The I-10 (Wallace) Tunnel ............................. 222 4.4.8 Shipping Pier Exposure to Storm Surge – Dock One at the McDuffie Coal Terminal ....... 233 4.4.9 Pavement Mix Design Exposure to Temperature Changes................................................. 251 4.4.10 Continuous Welded Rail Exposure to Temperature Changes ........................................... 263 4.4.11 Operations and Maintenance Activity Exposure to Climate Change and Extreme Weather Events .................................................................................................................. 272 U.S. Department of Transportation iii August 2014 Gulf Coast Study, Phase 2—Task 3.2: Engineering Analysis and Assessment 5. Lessons Learned .....................................................................................................................294 5.1 Introduction ......................................................................................................................294 5.2 Applicability of a General Process for Transportation Facility Adaptation Assessments ...............................................................................................................294 5.2.1 Lack of Engineering Guidance or Reference Materials for Considering Climate Change ............................................................................................................................... 296 5.3 Developing General Input Values for Engineering Designs ............................................297 5.3.1 Utilizing Climate Data in Engineering Assessments .......................................................... 297 5.3.2 Addressing the Design Storms vs. Modeled Future Storms ................................................ 298 5.3.3 Downscaling Climate Scenario Data for Engineering Design ........................................... 300 5.3.4 Considering