Final Report: Diagnosing and communicating the effect of climate variability on frequency of coastal inundation
Dates
Acquisition
2023-02-10
Summary
Increased coastal flooding due to sea-level rise (SLR) threatens the culture, habitat, and essential infrastructure of the Hawaiian and U.S. Affiliated Pacific Islands. The purpose of this project was to respond to the needs of Pacific Island communities for improved information about the frequency of coastal flooding—both in the near term and throughout the 21st century. Seasonal sea-level and flooding forecasts were produced by combining multiple types of information into a single forecast that performs better out to six months than any individual forecast. The forecasts are provided on a website created for this project. Projections of tidal flooding for the 21st century were produced for 35 island locations across the Pacific Ocean [...]
Summary
Increased coastal flooding due to sea-level rise (SLR) threatens the culture, habitat, and essential infrastructure of the Hawaiian and U.S. Affiliated Pacific Islands. The purpose of this project was to respond to the needs of Pacific Island communities for improved information about the frequency of coastal flooding—both in the near term and throughout the 21st century. Seasonal sea-level and flooding forecasts were produced by combining multiple types of information into a single forecast that performs better out to six months than any individual forecast. The forecasts are provided on a website created for this project. Projections of tidal flooding for the 21st century were produced for 35 island locations across the Pacific Ocean based on a novel technique developed to relate future tidal variations and sea-level rise to changes in flooding frequency. Results show that tidal variations can sometimes cancel the effect of sea-level rise on flooding, while other times tidal variations cause the frequency of flooding to increase rapidly. Such rapid increases are expected in Hawai‘i beginning in the mid 2030s. The analysis for all locations can be explored on website created for this project. Finally, local assessments were made for American S¯amoa and Pu‘uhonua o H¯onaunau (PUHO) National Historical Park based on observations and models that simulate how waves move from deep water to shore. The results from American S¯amoa will be will be incorporated into a forthcoming Sea-Level Rise Viewer for American S¯amoa. Results from PUHO were documented in a report demonstrating that high-tide flooding will become a chronic issue in the park by the mid 2040s while the extent of wave-driven flooding will be constrained by areas of higher land elevation.
