Coastal infrastructureForecasting future flooding in the Pacific Northwest

Published 3 April 2015

Unlike the South or East coast of the United States, coastal flooding in the Pacific Northwest comes primarily from large waves generated by major storms instead of hurricanes. The Pacific Northwest is dotted by small, low-lying, coastal cities where populations tend to cluster. These communities can be isolated and are susceptible to devastation from major storms that bring substantial wind, waves, and storm surge. With climate change, it is anticipated that storms will only become more frequent and intense, signifying a need to understand how the areas will be affected.

The Pacific Northwest is dotted by small, low-lying, coastal cities where populations tend to cluster. These communities can be isolated and are susceptible to devastation from major storms that bring substantial wind, waves, and storm surge. With climate change, it is anticipated that storms will only become more frequent and intense, signifying a need to understand how the areas will be affected.

David Hill, a researcher at Oregon State University, is focused on the hydrology and hydrodynamics in coastal areas, which represent the boundary between terrestrial and marine environments. His research on future levels of flooding in Tillamook Bay was published in the Journal of Geophysical Research in January 2015.

This particular project is a blending of our interests in estuarine and coastal hydrodynamics and our interests in climate change,” Hill said. “We’re interested in getting a good quantitative understanding of the extreme water levels we can expect from coastal flooding.”

Unlike the South or East coast of the United States, coastal flooding in the Pacific Northwest comes primarily from large waves generated by major storms instead of hurricanes.

We get big storms here, it’s not uncommon to see wave heights that are ten meters,” Hill said. “Those waves do a couple of things, they can overtop dunes and sea walls. There is also a curious effect where as those waves approach shore and break, they actually push the water up, creating a storm surge effect.”

Storm surge is the abnormal rise of water generated by a storm, causing extreme flooding in coastal areas. It is costly, often leading to the damage or loss of houses and businesses, as well as the potential loss of life. A TACC release notes that in a report released by the Intergovernmental Panel on Climate Change (IPCC), climate scientists detailed how carbon emissions will impact future climate, and in turn sea level rise. These changes in climate will also lead to an increase in extreme storms and flooding in the future.

Hill and his team of researchers wanted to quantify exactly how flooding will change in the Pacific Northwest on a decadal to century time scale. The researchers developed a novel approach to the issue by using climate data from the IPCC and directly modeling all of the components that cause flooding at the coast including, waves, tides, winds blowing over the surface of the ocean and estuaries, precipitation, and stream flow.