Cape Fear River flooding, 2018. (Photo by Matt Born / StarNews

NC - Why flooding from hurricanes in the Wilmington area could get a whole lot worse

The Cape Fear region is no stranger to flooding associated with tropical weather systems dumping massive amounts of rain on the region.

TJust in the past six years, Eastern North Carolina has seen two record-setting rainfall events, with Hurricanes Matthew in 2016 and Florence in 2018 each dumping more than 2 feet of rain − often on the same water-logged areas - and leading to billion-dollar property, public infrastructure and agricultural losses.

But a recent study out of Princeton University finds that hurricane-driven flood hazards in the Wilmington area could dramatically increase in coming decades due to climate change-driven weather changes boosting both the amount of precipitation in inland areas and the dangers from storm surge associated with increased sea-level rise closer to the coast.

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Avantika Gori, a doctoral student at Princeton, and Dr. Ning Lin, an associate professor of civil and environmental engineering at the university, looked at the interaction between sea-level rise and rainfall runoff to develop a model of what could happen during a massive storm event in the Cape Fear watershed. Using a physics-based storm simulations and new statistical models, the researchers quantified what could happen in certain storm events due to both increased storm surge − driven largely be sea-level rise − and more intense rainfall tied to a warming climate.

Maps  showing 100-year flood depths across the lower Cape Fear estuary for 1980-2005 (far left map) and in high-emission scenarios later this century.

"Traditionally, researchers are either looking at one aspect like coastal flooding and damage from storm surge or what's happening inland with the rains," Gori said. "What we wanted to do was look at the combination of the two, because that can make things a lot worse rather than just analyzing one or the other."

The picture they painted wasn't a pretty one.

The study, published in late November in the Advancing Earth and Space Science journal (AGU), found that by 2100 the combination of sea-level rise and increased rainfall could lead to a 27% increase in the 100-year flood extent, and a 62% increase in the 100-year flood volume along the Cape Fear Estuary.

Graphics showed areas of Brunswick County, particularly along Town Creek and near the mouth of the Cape Fear, seeing much larger areas inundated by floodwaters. And the sheer amount of water might not be the only concern. Getting the water out, in effect having it drain to the coast, could be an increased problem due to the volume of water being pushed inland due to increase storm surge − not to mention the challenges of levees, berms and raised roadways meant to channel the water toward those exit routes.

"It really was eye-opening to see what could happen," Gori said.

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