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University of Hawaii Online Tool Predicts Flooding, Sea Levels

Researchers developed a new forecast model to better predict large waves approaching the coast of West Maui, where sea-level changes and coastal erosion continue to imperil vital infrastructure and properties.

Hawaii Flooding.jpg
University of Hawaii researchers say an increase in wave-plus-tide-driven flooding has worsened coastal erosion on West Maui.
(Contributed Photo/Don McLeish)
University of Hawaii researchers recently developed an online forecast tool to alert residents when large waves threaten West Maui, a region that's grown increasingly vulnerable to wave-driven flooding and coastal erosion amid rising sea levels caused by climate change.

According to a university news release, the team designed a high-resolution Wave Run-Up Forecast model to monitor real-time conditions around several of the region’s shorelines and predict large-wave flooding nearly a week in advance, giving officials time to issue safety warnings.

Tara Owens, a coastal specialist and co-investigator, said the new forecast model and online tool could be used by government agency officials for emergency response planning, as well as for construction projects designed with nearshore conditions in mind.

“When the forecast indicates that impacts are anticipated, actions might include warnings for safety issues or traffic impacts on coastal roads where wave overwash is common ... avoidance of affected beaches, messages in resort areas to guests about changing ocean conditions, and relocation of canoes, kayaks or lawn furniture,” she told Government Technology after last week's announcement of the model.

Owens said the team's model was the culmination of a three-year project funded through a $500,000 grant from the National Oceanic and Atmospheric Administration's Regional Coastal Resilience Program. Additional support came from the Joint Institute for Marine and Atmospheric Research, University of Hawaii Sea Grant program and Pacific Islands Ocean Observing System.

According to researchers, nearshore conditions around West Maui have grown increasingly unpredictable in recent years. Researchers say these ever-changing conditions have imperiled property and vital infrastructure like the Honoapiʻilani Highway, the only access point to and from the area.

“West Maui has an extremely complex nearshore environment. Waves, currents and water levels are influenced by the highly variable ocean floor, which ranges from deep ocean channels to shallow plateaus. This dynamic environment can lead to significant, yet unexpected, wave run-up and coastal flooding,” co-investigator Douglas Luther explained in a university news release.

Owens said researchers built upon other forecast models similar to those used by the National Weather Service for measuring coastal wind and making wave projections. From there, the team developed and augmented its new BOSZ, or “Boussinesq Ocean and Surf Zone" model, to produce detailed simulations of individual wave dynamics using nearshore sensors by the coast.

Though the science of wave modeling isn't completely new, Owens said, the model can better predict exactly when and where major flooding will occur.

“What is very unique about this project is operationalizing the model to predict potential wave impacts in real time," she said, adding that wave modeling is continually evolving and improving.

The model was created with the help of local residents who provided Owens' team with hundreds of photos showing examples of flooding on West Maui.

“The community photos were a crucial element to provide site-specific wave flooding examples along the shoreline to identify thresholds when light, hazardous and critical impacts may occur,” she said.

The new tool could be applied to monitor coastal conditions elsewhere, such as in Florida, where climate change researchers say the sea levels near the shore are projected to continue rising by as much as an inch every three years.

The forecast model could also assist engineers in developing flood mitigation barrier projects similar to the ones currently being built in Venice, Italy, a city that climate scientists say is on the verge of sinking following record-breaking floods in recent years.

In order to better respond to sea-level changes, Owens said, researchers must predict the frequency of wave-driven flooding, as well as the force of those waves eating away at shorelines.

“Erosion and high-wave impacts are expanding and worsening in Hawaii, and throughout the Pacific, in the face of sea-level rise. Changing water levels will affect how the waves interact with the shoreline, and climate models also predict increasing wave energy,” she said. “A better understanding of the phenomena contributing to wave impacts is important to enhance safety and to inform protection and preservation of infrastructure, sensitive coastal ecosystems, recreation, and cultural sites and uses.”

The team hopes to further improve the model's wave forecasting capabilities such that officials will be able to develop long-term erosion and flood mitigation projects in the years ahead. Owens said the team also hopes to expand its work throughout Hawaii in the near future.

“One of the next steps for the project team is to look to the future to better understand how changing water levels with sea-level rise will increase wave energy at the shoreline. Wave [characteristics] will be simulated for different wave conditions with various sea-level rise scenarios,” she said.
Brandon Paykamian is a staff writer for Government Technology. He has a bachelor's degree in journalism from East Tennessee State University and years of experience as a multimedia reporter, mainly focusing on public education and higher ed.