The North Carolina Department of Transportation (NCDOT) Ferry Division has faced a number of environmental challenges in recent years, including Hurricane Dorian (2019) which caused extensive service disruptions as well as the need to use the ferry system to remove 9,000 truckloads of storm debris (totaling over 6,650 tons) from Ocracoke Island (Virginian-Pilot, 2020). Shoaling caused by inlet processes has also caused delays and interruptions and necessitated frequent dredging along the Hatteras Island to Ocracoke Island route. Additionally, changes in channel depth and orientation have resulted in the Ferry Division having to re-direct ferry routes and implement structural stabilization measures. Storms with extreme rainfall such as hurricanes Matthew (2016) and Florence (2018) can cause extensive flooding and problems for facilities on the sound side shorelines. Sea level is currently rising and rates of rise are predicted to increase for the foreseeable future [IPCC 2021 projects sea level rise to 2100], which will amplify storm surge and wave impacts. There is a need to evaluate the vulnerability of the system’s facilities across the state, both now and as climate change progresses. This will enable the Division to plan for adaptation projects to ensure that the system operates successfully into the future.
As NCDOT plans for future transportation system resilience, there is a need for statewide assessment of current and future vulnerability of each of the transportation modes. The NCDOT Resilience Strategy Report (2021) describes NCDOT’s short-term strategies for resilience, including “address gaps in resilience planning and standards for ferry.” This is described as “assess ferry channels and conduct vulnerability and criticality assessments to address future impacts.” The proposed research will directly address this specific short-term strategy.
The aims and scope of the study will be (a) to assess the vulnerability of all of the Ferry Division’s infrastructure assets with respect to natural hazards (present and forecast to the 2040 and 2060 planning horizons); (b) to assess the condition of ferry channels at present as well as potential climate impacts (c) to prioritize assets for adaptation measures where needed; and (d) to provide recommendations on potential adaptation options as well as timeframes for implementation and ballpark cost estimates.
The Federal Highway Administration (FHWA's) Vulnerability Assessment and Adaptation Framework, 3rd Edition (FHWA-HEP-18-020), will serve to guide the proposed vulnerability assessment of ferry assets. This framework is designed to help transportation agencies and their partners to assess the vulnerability of transportation systems to extreme weather and climate effects. The five steps to conduct a vulnerability assessment include: 1) Set Objectives & Define Scope; 2) Compile Data; 3) Assess
Vulnerability; 4) Analyze Adaptation Options and 5) Incorporate Results Into Decision-Making. These steps correspond to Tasks 3 through 7 in the proposed study. Tasks 1 and 8 are study project management tasks; the Kick-Off Meeting and Final Report and Deliverables, respectively. Task 2 is an expansion of the preliminary literature review that was conducted for the preparation of this proposal.