Department of Commerce National Oceanic and Atmospheric Administration Office of National Marine Sanctuaries Office of Response and Restoration Risk Assessment for Potentially Polluting Wrecks in U.S. Waters Distircyt March 2013 National Oceanic and Atmospheric Administration Office of National Marine Sanctuaries Daniel J. Basta, Director Lisa Symons John Wagner Office of Response and Restoration Dave Westerholm, Director Doug Helton Department of Commerce National Oceanic and Atmospheric Administration Office of National Marine Sanctuaries Office of Response and Restoration Risk Assessment for Potentially Polluting Wrecks in U.S. Waters Distircyt Images of tanker Dixie Arrow portraying types of information used to assess pollution risk and construct risk assessment packages. Top left: Historical photograph of Dixie Arrow sinking. Bottom left: Historical USCG sinking assessment of Dixie Arrow depicting torpedo impact locations. Right: Underwater site of the shipwreck in its current condition off the coast of Cape Hatteras, North Carolina. March 2013 Table of Contents Table of Contents Acknowledgements ....................................................................................................................... v Dedication ...................................................................................................................................... vi Executive Summary .................................................................................................................. ES-1 Project Background ................................................................................................................................ ES-1 Project Results and Summary ................................................................................................................ ES-3 Section 1: Introduction Background ..................................................................................................................................................1 Goals and Organization of this Report .........................................................................................................2 Problem Definition/Framing the Issue...........................................................................................................3 History of Concern for Potentially Polluting Wrecks ...........................................................................3 Historical Context/Maritime Landscapes/Battle of the Atlantic ..........................................................4 Other Hazards from Wrecks .........................................................................................................................5 Non-petroleum Cargo ........................................................................................................................5 Munitions ...........................................................................................................................................6 Legal Issues .................................................................................................................................................6 Case Histories – U.S. ..................................................................................................................................7 International Wreck Case Studies and Risk Assessment Approaches .......................................................11 Case Histories – International ..........................................................................................................11 International Risk Assessment Efforts .............................................................................................12 Section 2: Prioritizing Potentially Polluting Wrecks in U.S. Waters ......................................... 15 Initial Wreck Screening Process .................................................................................................................15 Initial Screening Factors ..................................................................................................................15 Initial Screening Factors: Data Sources ...........................................................................................16 Secondary Wreck Screening Process ........................................................................................................17 Archival and Historic Research ........................................................................................................17 Shipwreck Site Formation ................................................................................................................19 Corrosion and Age ...........................................................................................................................22 Interpreting Sinking Records ......................................................................................................................24 Casualty Information ........................................................................................................................24 Wreck Condition and Salvage..........................................................................................................27 Vessel Risk Factors ....................................................................................................................................27 Pollution Potential Tree ..............................................................................................................................28 Section 3: Consequence Analysis and Results: Getting to the Tradeoffs ............................... 35 Use of Worst Case Discharge and Most Probable Discharge .....................................................................35 Enviornmental Impact Modeling ..................................................................................................................36 Introduction ......................................................................................................................................36 Model Description ............................................................................................................................36 Vessels Modeled .............................................................................................................................37 i Table of Contents Model Inputs ....................................................................................................................................43 Analysis of Results ..........................................................................................................................46 Model Limitations .............................................................................................................................48 Risk Scoring and Ranking ...........................................................................................................................48 Probability vs. Consequences..........................................................................................................48 Ecological Resources at Risk (Eco RAR) ..........................................................................49 Socio-economic Resources at Risk (SRAR)......................................................................50 Water Column Impacts ....................................................................................................................53 Water Surface Impacts ....................................................................................................................54 Shoreline Impacts ............................................................................................................................54 Summaries of Risk Factor Scores ...................................................................................................55 Final Resources at Risk Score Determination .................................................................................56 Challenges and Limitations of Risk Assessment .............................................................................57 Distributions of RULET Wrecks by U.S. Coast Guard District .........................................................58 Section 4: Considerations for Reducing the Risks of Potentially Polluting Wrecks in the United States ..................................................................................................................... 74 Factors Affecting Planning for Assessment and Removal Operations ........................................................75 Wreck Assessment and Oil Removal ..........................................................................................................78 Tools and Technologies ...................................................................................................................78 Diving ........................................................................................................................................79 Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) ............79 Sonar Technology ....................................................................................................................80 Ultrasonic Thickness (UT) Hull Gauging ...................................................................................81 Neutron Backscatter .................................................................................................................83 Oil Removal Technologies ...............................................................................................................84