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Measurements of wave runup on an atoll island using LiDAR

Sam Rose·Chris Blenkinsop·Gerd Masselink·Ian L. Turner·Kévin Martin·Curt D. Storlazzi
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Abstract

Coral atoll islands are highly susceptible to flooding and overwash due to their low-lying nature and the impacts of climate change. This study presents the first long-term, high-resolution field dataset of wave runup on a coral atoll island, collected over 6 weeks using a shore-mounted LiDAR scanner. The LiDAR data captured swash dynamics on a steep coral rubble beach fronted by a conglomerate platform. Results demonstrate the limitations of depth-based swash extraction methods, particularly for thin swash events, where depth thresholds lead to significant underprediction. Further analyses show that low-frequency oscillations (infragravity and very-low-frequency bands) and high-frequency components (transitional bores) dominate the spectra on the reef platform and are reflected in the swash signal. The displayed swash spectra highlight the critical role of low-frequency oscillations in extreme runup events, emphasizing their contribution to island flooding and overwash.

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Sam Rose, Chris Blenkinsop, Gerd Masselink, Ian L. Turner, Kévin Martin, Curt D. Storlazzi. 2026-03-05. Measurements of wave runup on an atoll island using LiDAR. https://pubs.usgs.gov/publication/70262912

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