HDOT Climate Resilience Action Plan | May 2021

Figure 5 Selected Repairs Sites on HDOT-Highways Roads Associated with Emergencies Since 1997 (clockwise from top left: Kaua‘i County, City and County of Honolulu, Hawai‘i County, and Maui County) Source: State-Owned Roads: HDOT Highways Division, LRMS; Base maps: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community; World Ocean Reference: Esri, GEBCO, NOAA, National Geographic, Garmin, HERE, Geonames.org, and other contributors

HAZARDS EXAMINED IN THIS ACTION PLAN Understanding and proactively addressing how roads are exposed to climate-related hazards helps inform State agencies and communities about changing environmental conditions that may impact the performance of the highway system. The Exposure Assessment report describes where HDOT roads, bridges, culverts, and tunnels may be exposed to hazard events associated with changing climate conditions. The Exposure Assessment report builds on analyses undertaken to estimate future conditions by international (e.g., the Intergovernmental Panel on Climate Change), national (e.g., NOAA and USGS), and local researchers (e.g., the University of Hawai‘i, HDOT). These overviews use the latest scientific data and analytical approaches available for each hazard specific to Hawai‘i. Table 1 shows the exposure assessments in this Action Plan and described in the Exposure Assessments document accompanying this Action Plan. Each of the exposure assessment technical overviews provides the following: ⊲ Information on previous works and existing data ⊲ The methodology used for determining the exposure of assets to the hazard of interest

Table 1 Exposure Assessments

Exposure Assessments

Hazards Examined

• Rockfalls and landslides • Sea Level Rise (marine flooding and groundwater inundation) • Annual high wave flooding • Coastal erosion • Storm surges

Climate-related exposure assessments

• Tsunamis • Wildfires

Other exposure assessments

• Lava flows

⊲ The results of the application of the methodology, along with maps and charts to communicate the degree to which assets may be affected ⊲ Recommendations for the HDOT ⊲ Improvements to existing data and models to support the assessment of risk and resilience related to the State road system

14 HAWAI I HIGHWAYS C L I MAT E ADAP TAT I ON ACT I ON P L AN