Extreme weather exposes more people and places to flooding

As extreme weather events become more frequent and intense due to climate change, the number of people and places exposed to flooding is likely to increase. Until recently though, surprisingly little research has been conducted about how floodplain development patterns vary across communities. 

Now, a team of scientists led by the University of North Carolina (UNC) has found that new housing construction in flood-prone areas has significantly contributed to increasing risk across North Carolina, regardless of community and government efforts to reduce flood damage. According to the experts, more than ten new residences have been built in this state’s 100-year floodplains for each residence removed through government buyouts (through which flood-prone properties are purchased and restored to open space).

“We’ve been putting more and more people in harm’s way, and we see that pattern across the state – in coastal and inland communities, in urban and rural areas,” said study lead author Miyuki Hino, an assistant professor of City and Regional Planning at UNC. “Communities across the state are working to reduce their flood risk through buyouts, elevating homes, and upgrading infrastructure, but it’s harder to see those benefits when we’re adding more houses and people to floodplains at the same time.”

The researchers investigated new construction across five million parcels in North Carolina in order to develop standardized measures of floodplain development and assess the relationship between flood risk management initiatives and development outcomes.

“We find that community effort towards flood risk management doesn’t always correspond to limiting floodplain development,” said study co-author Antonia Sebastian, an assistant professor of Earth, Marine, and Environmental Sciences at UNC. “Rather, communities rewarded by FEMA for high effort were continuing to allow more housing to be developed in the floodplain.”

Since local governments play a major role in flood risk management, knowing the areas where communities are building in floodplains, and clarifying what measures are needed to encourage development in safer areas, is crucial for reducing damages and risk.

“Strategic planning and zoning can encourage growth in safer areas and maximize open space in floodplains. As we see heavier downpours and wetter hurricanes, managing development is critical to reducing flood damages in the long term,” Hino explained.

“We have long assumed that communities across the state have continued building in floodplains, at least to some extent. But, the sheer scale of this construction is really surprising, especially in that it dwarfs the large-scale efforts to move homes out floodplains and out of harm’s way. The enormous public costs of buyouts are also shared by local governments – in many cases, the same local governments encouraging new building in floodplains. Today’s new floodplain construction may be tomorrow’s buyouts,” concluded co-author Todd BenDor, an expert in Sustainable Community Design at UNC.

The study is published in the Journal of the American Planning Association. 

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By Andrei Ionescu, Earth.com Staff Writer

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