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Transportation, Climate Change & Extreme Weather Vulnerability Assessment Webinar Series - May 30, 2013

Session 2: System-Level Vulnerability Assessments

May 30, 2013 3:00-4:30 PM EDT


Available at:

(Note: a transcript is also being posted with this summary)


The presenters included: Rob Kafalenos of the Federal Highway Administration (FHWA) Office of Natural Environment, Carol Lee Roalkvam of Washington State Department of Transportation (WSDOT), Sara Polgar of San Francisco Bay Conservation and Development Commission (BCDC), Stefanie Hom of Metropolitan Transportation Commission (MTC), and Jeffrey Perlman of New Jersey Transportation Planning Authority (NJTPA).

Session Overview:

Understanding how climate change and extreme weather will affect a given transportation network is a key first step for transportation planning. Session 2 of the Webinar Series focused on the use of transportation asset information and climate projections to identify vulnerabilities in transportation infrastructure.

FHWA's Climate Change and Extreme Weather Vulnerability Assessment Framework, which serves as the outline for this webinar series, is modeled after five pilot projects conducted by partner Metropolitan Planning Organizations (MPOs) and State Departments of Transportation (DOTs). The second session in the webinar series included presentations from three of these five pilot programs to serve as example applications of system-level vulnerability and risk assessments. The three organizations each employed different methodologies in conducting their assessments and represent the a wide range of approaches.

Washington State DOT's Vulnerability Assessment: Asking the "Climate Question," Carol Lee Roalkvam

WSDOT's pilot project made use of $189,500 in FHWA matching funds to develop qualitative vulnerability rankings for all state-owned assets based on asset management and cost/risk assessment tools, climate change data, and, notably, field personnel knowledge of threats and assets. WSDOT's goal for this assessment was to preserve existing assets in a changing environment. To meet this goal, WSDOT chose an approach that involved understanding climate change within the existing statewide asset management framework. Although the assessment did not extend to any external assets (e.g. local street networks or privately-owned railroads), it considered the state-owned transportation network in its entirety. As a result, WSDOT's pilot has the broadest scope of the five pilot projects included in the Vulnerability Assessment Framework.

In 2010 FHWA published a draft Risk Assessment Model that WSDOT used as a basis for conducting its risk assessments, with some modifications. The first step of WSDOT's assessment involved determining asset criticality. To accomplish this, WSDOT held 14 interdisciplinary workshops with field staff, local maintenance supervisors, engineers, and other staff with deep knowledge of particular assets. During the workshops, WSDOT staff defined the character of each individual highway segment, ferry terminal, or other asset, including its use, functional class, and level of redundancy.

The second step in WSDOT's vulnerability assessment process was to identify climate threats resulting from temperature, precipitation, hydrologic shifts, and sea level rise (SLR). WSDOT accomplished this stage of the process by using past experience to gauge future impacts and climate threats. During the asset criticality workshops, WSDOT shared digital elevation maps,basin hydrology maps, projected soil moisture changes, and other information in order to qualitatively assess the consequences of climate change and their specific impacts on WSDOT's many transportation assets. Each asset was assigned a numbered record impact score, which ranged from "reduced capacity" to "temporary operations failure" to "complete catastrophic failure." The results were displayed on a map that depicted the vulnerability of the statewide transportation assets.

WSDOT's vulnerability assessment underscores the value of its current asset management and retrofit programs, as well as the utility of capturing its field staff's unique qualitative knowledge of particular assets.

Adapting to Rising Tides: Transportation Vulnerability and Risk Assessment Pilot, Sara Polgar and Stefanie Hom

Adapting to Rising Tides is a collaborative partnership between MTC, BCDC, the California Department of Transportation (Caltrans), FHWA, and local partners. The goal of the project is to increase the preparedness and resilience of Bay Area communities to SLR and other climate change impacts, including more frequent flooding, elevated groundwater, salinity intrusion, and erosion of shoreline protection. The study focused on Alameda County as a sub-region within the larger San Francisco metropolitan area.

Like WSDOT, MTC and its partners also made use of the FHWA pilot model for conducting vulnerability assessments, with a few modifications. MTC decided that asset screening was premature for their assessment because they had not yet conducted the requisite consequence analysis. Instead, MTC selected multi-modal assets for its assessment. The assets were selected based on physical characteristics, functional characteristics, jurisdiction, and social/economic functions. Next, MTC developed shoreline categories based on an area's primary function and potential to protect against flooding. MTC also developed inundation maps for six climate scenarios based on two SLR projections (16 inches by mid-century and 55 inches by end of the century) and three water level conditions (hide tide, extreme hide tide, and extreme high tide plus locally generated wind waves). The shoreline categories and inundation maps enabled MTC to visualize transportation vulnerability and risk.

The resulting risk assessment drew on two factors: the likelihood of an impact and the magnitude of the consequence. MTC based consequence on the cost and time required to replace an asset, the socio-economic impact of inundation, the effect on public safety, and the degree of redundancy in the system. MTC combined this risk rating with asset characteristics and vulnerability ratings into a risk profile for each asset being studied. These unique risk profiles, which are included in the larger report, are useful in informing the development of appropriate adaptation measures because they display outcomes in a more accessible format than a broader reference report.

Lessons learned from the pilot include the difficulty of prioritizing assets prior to the completion of consequence analysis, the utility of SLR exposure as a filter for asset selection, the importance of arriving at an accepted definition of exposure, sensitivity, and adaptive capacity in developing the definition of vulnerability, and the value of soliciting stakeholder input early in the risk assessment process, in order to make the process transparent and to better define consequence impacts criteria.

Assessing the Vulnerability of New Jersey's Transportation System to the Impacts of Climate Change, Jeffrey Perlman

NJTPA's process of identifying vulnerable transportation assets included articulating objectives, selecting and characterizing relevant assets, assessing asset criticality, identifying key climate variables, and ranking vulnerabilities. The agency's approach to the pilot differed from WSDOT's in that it relied on a quantitative, rather than qualitative methodology, although NJTPA is considering incorporating interviews with field staff into future vulnerability analyses.

While WSDOT conducted a statewide analysis, NJTPA limited their analysis to a project study area, which it further divided into one central and one coastal study area. The study area crossed three MPO jurisdictions: NJTPA, the South Jersey Transportation Planning Organization (SJTPO), and the Delaware Valley Regional Planning Commission (DVRPC). Relevant assets for the vulnerability analysis included roads, bridges, tunnels, railways, airports, wetlands, and navigation facilities. In assessing criticality, NJTPA rated its inventoried assets in terms of usefulness for evacuation, access provided to jobs, and traffic volumes.

NJTPA considered three climate threats: SLR and storm surge impacts, temperature and precipitation, and inland flooding impacts. The agency assessed climate impacts to assets according to three greenhouse gas emissions scenarios and threshold analyses of temperature, precipitation, and cold/frost days. NJTPA's resulting climate change projections revealed significant changes in days above 95 degrees Fahrenheit, consecutive days without precipitation, frequency of storms, and days with frost by 2050 and 2100.

To conduct the vulnerability analysis, NJTPA built a GIS database that incorporated LiDAR data for ground elevations, local subsidence data, and projected SLR and storm surge estimates into the roadway and rail network, in order to identify assets that are vulnerable to flooding and inundation. The resulting analysis, which predicted the flooding of specific transportation assets and other extreme climate impacts, is a powerful tool for planning.

NJTPA also analyzed the impacts of Hurricanes Irene and Sandy by geo-referencing inundated segments of the roadway network. The agency compared actual inundation and inland flooding from the storms against the projected models of SLR and storm surge. NJTPA found that the model matched reality well.

As a result of this first pilot, NJTPA is working with FHWA to conduct a vulnerability analysis and adaption analysis across the New York metropolitan area. During the proposed 18-24 month study, the project partners will look at lessons learned from Hurricane Sandy, including assets damaged by the storm and adaption strategies that might improve resiliency region-wide.

Updated: 10/20/2015
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