分野別セミナー

Despite its vast coastline and unique coastal ecosystems and resources, Hawai‘i Island has never had a comprehensive shoreline assessment of coastal vulnerabilities or any systematic monitoring of long-term shoreline change rates. Consequently, Hawai‘i Island is in a weak position for adapting to the potential impacts of sea-level rise (SLR) and coastal erosion. This project quantifies historic and current coastal erosion rates for three diverse coastal geomorphologies found on Hawai‘i Island, to better predict and manage changes due to SLR. Shoreline records, including historic aerial photographs and three-dimensional datasets collected from small unmanned aerial systems (sUAS) have allowed us to quantify erosion and accrual at locations that represent calcareous beaches (Hāpuna State Beach Park), sea cliffs (Honoli‘i Beach Park), and subsiding coastal lava fields (Kapoho Tide Pools). These data are merged with SLR and subsidence projections to estimate future impacts to coastal communities and natural and cultural resources. Results from this study suggest that Hawai‘i County’s current coastal zone management strategies are not adequate in the face of contemporary coastal processes, and each coastal study site will be significantly impacted if SLR continues to increase as expected. Results from this study will be incorporated into the county's GIS database and made available to the public through the statewide GIS system. These data will provide a visualization tool for coastal communities and Hawai‘i County workers to understand local impacts of SLR and consider necessary adaptations.