Enhancing the Resilience of Idaho’s Transportation Network to Natural Hazards and Climate Change

This research compiled information on past landslides, including date-referencing and geo-locating events; analyzed and mapped variables contributing to slide susceptibility; demonstrated the conditions of the future climate models that may increase landslide hazards; and designated the transportation routes most vulnerable to weather-triggered landslides. The study area was reduced to the northern and central counties, as primary and secondary transportation routes in the remainder of Idaho rarely cross areas of high topographic relief. The slide events located in this pilot study generally occur in areas of high susceptibility based on aspect, slope, and geology. The transportation routes most at risk given projections of climate change are in the northern-most counties of Idaho: Interstate 90 and northern sections of U.S. Highway 95. Luckily, these areas generally have dense canopy cover, an indicator of slope stability. However, land use changes, forestry management policy changes, and the threat of large-scale wildfires could each impact slope stability. With a larger, detailed record of landslide events, predictive models for homogeneous “landslide” regions could be combined with historical and projected climate data to isolate specific sections of highways most vulnerable to extreme weather-triggered slope failures. LiDAR could greatly reduce the time and cost of compiling a landslide inventory for Idaho.