Research Projects 2018-2020

West Maui wave run-up forecasts

Co-INVESTIGATOR: Mark Merrifield
Graduate Student: Camilla Tognacchini

Scenic beach pictures showing extreme erosion at the very base of the Royal Kahana hotel.
Kahana Beach in West Maui illustrates the extreme beach erosion due to increasing wave impacts from sea level rise now threatening buildings and infrastructure.

The long-term rising trend in sea level (typically, an inch or so every 10 years around Hawaiʻi) alone will not be obvious to the casual observer at the seashore. What will become more apparent over time is that the high tides tend to be higher than “normal” and tend to last longer, flooding the low-lying shore lands more frequently and for longer periods.  Such flooding events are intensified, especially on Pacific Islands, by the occasional arrival of large swells from distant storms, resulting in even higher flooding events with more violent wave-driven inundation (which we call “run-up” events). West Maui is already impacted by chronic shoreline erosion due to wave run-up events. Buildings and local infrastructure are threatened by regular seasonal wave run-up and the attendant coastal erosion. Even worse, these events are anticipated to become more severe and more common due to the sea level rise and higher wave energies expected from climate change. In order to mitigate the impacts of these episodic flooding events, early warning is essential. We plan to develop run-up event forecasts up to a week in advance for the vulnerable West Maui shores by first collecting and analyzing appropriate water level and water current data, then applying well-understood and previously used methods of forecast model development. The forecasts, which will update every 3 hours, will be validated with the help of citizen scientist observers along the shoreline. We anticipate that coastal managers, emergency management personnel, property owners, and the general public will regularly use the forecasts to make short- and long-term decisions about how to prepare for and respond to coastal erosion and flooding impacts. The forecasts will enhance planning and response to such coastal erosion and flooding, thereby improving community and economic resilience.