ABSTRACT
Krivova, M.; Olsen, M.; Allan, J.; Parrish, C.; Leshchinsky, B.; Senogles, A.; Herrmann, J., and Dundas, S., 2024. Vulnerability assessment of risk for a coastal highway in Oregon, U.S.A.
Threading its way through Oregon, U.S. Highway 101 operates as a crucial conduit, intertwining functional necessity with the aesthetic appeal of sweeping coastal vistas. Unfortunately, many locations along this vital route are under constant threat from coastal hazards, such as seacliff erosion, landslides, and recurrent wave runup leading to overtopping and flooding. Given the daunting challenges associated with maintaining functional infrastructure in such rugged, dynamic terrain, as well as the balance between the preservation of the natural state of the coastline and the infrastructure providing access, sites must be prioritized for mitigation. Using quantitative assessment methods, such as the Coastal Vulnerability Index (CVI), can play a pivotal role in systematically identifying high-risk sites in need of remediation. Based on the findings of previous studies, the CVI was tailored to assess the vulnerability of the highway system to coastal geologic hazards. In this study, 71 hazardous sites were pinpointed for evaluation and possible remedial action. To capture the spectrum of hazards faced at each site, 26 parameters were used and classified into three primary categories, namely inundation, erosion, and landslides. This study presents a unique approach in implementing the CVI by considering the potential uncertainties in the calculations. The novelty lies in the usage of a Monte Carlo simulation to assign weights based on the uncertainties of each parameter. This innovative simulation approach enables assessment of the sensitivity of the overall CVI estimation based on the influence of parameter uncertainties. Ultimately, this approach provides a more robust, less subjective, and comprehensive vulnerability assessment process than current implementations of CVI that do not incorporate uncertainty.
