Uncovering JAPA

Considering Flood Risk in Development Decision Making

Between 1991 and 2020, there were 29 major disaster declarations for floods or storms in the state of North Carolina. Climate change has led to more frequent major flood events, prompting the adoption of various flood mitigation strategies. These include public buyouts of at-risk properties and federal floodplain management incentive programs, such as the Community Rating System (CRS).

Rethinking Heat Action Plans for Buildings

Despite the notable uptick in major flood events in North Carolina, new development in floodplains has far outpaced buyouts. However, in "Growing Safely or Building Risk? Floodplain Management in North Carolina," (Journal of American Planning Association, Vol. 90, No. 1) Miyuki Hino, Todd K. BenDor, Joran Branham, Nikhil Kaza, Antonia Sebastian, and Shane Sweeney explore the effectiveness of CRS participation and buyouts.

The authors found that CRS participation and buyouts did not consistently lower new floodplain development. Their findings underscore the need to consider flood risk more urgently in development decision-making.

The authors measured high versus limited levels of floodplain development at the scale of community (roughly equivalent to the U.S. Census designation 'places'). The authors found that as the number of buyouts in a community increased, the more likely they were to have high levels of floodplain development.

They also found no statistically significant correlation between voluntary participation in the CRS program and the level of floodplain development. This challenges the preconceived understanding that buyouts and CRS participation might indicate communities with flood mitigation measures that would prevent new floodplain development.

Figure 1: Floodplain development patterns in developable land.

Figure 1: Floodplain development patterns in developable land.

Socioeconomic Dynamics of Flood Risk

The factors that best explained the new floodplain development were median home prices and proximity to the coast. As median home prices increase, inland communities become less likely to have high levels of new floodplain development. For coastal communities, it was the inverse: as median home prices increase, the likelihood of a community having a high level of new floodplain development also increases.

The authors suggest that the economic and geographic stratification of new floodplain development underscores that 'risk' is a socially constructed concept. Wealthier communities near the coast may be more willing to take on flood risk, while in inland communities, poorer households may lack affordable alternatives and end up in high-risk flood areas.

Although avoiding development in floodplains is not the only indicator of successful flood mitigation, the authors argue that their findings do indicate room for improvement when it comes to managing new development, especially in areas that are at risk of climate-induced hazards. They suggest that further research into the factors that affect what risk management strategies communities use is needed and urge planners to consider factors beyond buyouts and CRS participation when assessing new development in high-risk flood areas.

Top image: iStock / Getty Images Plus - David Garrison

Felix Rosen is a master's student in the urban planning program at Harvard University Graduate School of Design.

February 1, 2024

By Felix Rosen