Characterizing Humboldt Bay's shoreline to determine coastal erosion and flood risk in the face of sea level rise.

This thesis project seeks to characterize shoreline erosion and the role of shoreline slope/type in coastal flood risk along a section of Humboldt Bay to help advise the California Department of Transportation (Caltrans) in their efforts to plan for sea level rise (SLR). At-risk sections of the 101-freeway safety corridor between Arcata and Eureka are of significant concern and are the focus of this project. Over a century of shoreline evolution and the role of land use changes are investigated using georeferenced historical maps, aerial imagery and historian records. Decadal shoreline changes are quantified using airborne lidar, including a recent survey from a Cal Poly Humboldt drone. Shoreline types (e.g. riprap, salt marsh) and slopes are characterized along transects with 100m alongshore spacing and used as input into the EurOTop equations for wave runup and overtopping. Various SLR and adaptation scenarios are considered, highlighting the benefits of natural shoreline infrastructure.