Conclusion

This section briefly summarizes the results for Pu‘ukoholā Heiau NHS and Kaloko-Honokōhau NHP.

This report completes an assessment of coastal vulnerability to wave overtopping, sea-level rise, and flooding for two national park units in the Pacific Islands Network. Products included with this report include maps of coastal inundation and historical shoreline change, and digital elevation models of shoreline morphology. The identification of vulnerable sections in the two parks will allow NPS managers to monitor and possibly move cultural structures that might be threatened by coastal hazards.

Pu‘ukoholā Heiau NHS and Kaloko-Honokōhau NHP currently experience impacts from coastal hazards including large swell, tsunamis, and coastal erosion. The impacts include damage to coastal landmarks, archeological sites, and coastal habitats with local flora and fauna. These impacts will be greatly increased under future sea level conditions. The clearest indication of the effects of sea level is the increase of seasonal wave damage. To protect the historic sites near the coast, continuous monitoring of wave action should be done, specifically monitoring before, during, and after annual high tide events. Frequency of monitoring should increase as seasonal wave damage increases. Areas that will be threatened by sea-level rise include Pelakane Beach and Ala Kahakai NHT in Pu‘ukoholā Heiau NHS. Kaloko Seawall, the beach fronting ‘Aimakapā Fishpond, and ‘Ai‘ōpio Fishtrap in Kaloko-Honokōhau NHP are at greatest risk of deterioration due to coastal impacts. Tsunami hazards appear to be minimal for both parks.