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Abstract

Puʻuhonua O Hōnaunau National Historical Park, located south of Kona on the western shore of Hawaiʻi Island, is a significant site in Hawaiian culture and history. Park stewards have documented increasingly frequent impacts to park assets in recent years due to the compounding effects of sea-level rise, sea-level anomalies, astronomical tides, and surface gravity waves. Here we present a co-developed study of compound shoreline impacts affecting Puʻuhonua O Hōnaunau that addresses the needs and questions of park stewards. We utilize in situ observations of water level from an array of nearshore pressure sensors to validate a high-resolution 2D wave-transformation model (SWASH) that captures wave-driven contributions to total water level at the park shore. We find that the magnitude of wave-driven impacts is highly sensitive to small changes in swell angle, and that the nature of wave-driven impacts varies substantially within the park bounds due to the complex bathymetry and coastline of the region. We combine the model results with regional wave hindcasts, sea-level data, and projections of sea-level rise to quantify the frequency and extent of future tidal- and wave-driven flooding events in Puʻuhonua O Hōnaunau. Finally, we demonstrate distillation of our results for use by park stewards in the form of co-developed materials and products, including a novel augmented reality (AR) smartphone app currently available from the iOS and Google Play app stores.