In Brief:
Not all communities face the same amount of danger from flood exposure, but their respective risks vary in some surprising ways. Although Native American and Hispanic communities face greater-than-average risks, Black and Asian households actually are at lower risk of flooding than white households nationwide, according to a new study.
“‘Surprising’ would be the one adjective I would put on it,” says George Galster, an urban affairs professor at Wayne State University in Detroit and lead author of the paper. “The presumption was that virtually all minority groups everywhere are going to be disproportionately in danger, and we did not find that.”
Even setting aside potential racial disparities, the more detailed picture of flood risk has implications for state and local policymakers. Local leaders have become more attentive to flood risks in recent years after taking a fairly lax attitude to building in floodplains for decades, Galster says. Nonetheless, they may be permitting dangerous construction if they’re going by the existing federal measures of flood risk.
Galster and his co-authors describe their paper as the first “national portrait of the annual probability of experiencing flooding faced by members of different racial/ethnic and income groups.” They used a new set of flood data from the First Street Foundation that provides a more granular picture of property-level risk than the flood zone maps published by the Federal Emergency Management Agency.
Galster has spent the last 50 years studying urban segregation and racial discrimination in housing markets. He became interested in the racial dynamics of climate risks like flooding through conversations with his son, Joshua Galster, an environmental scientist at Montclair State University in New Jersey who co-authored the paper.
Much research has explored the disparate impacts of environmental and climate risks, showing that Black people and other minority groups are disproportionately exposed to, for example, hotter temperatures and air pollution. But there was a gap in the research when it came to understanding how flood risks intersect with race at a national level.
“I really couldn’t find a lot of research out there that has explored, explicitly, this question of who’s most likely to get flooded out,” says George Galster.
Underestimating the Danger
The First Street Foundation data measures risks from coastal flooding, river flooding and pluvial flooding — the type of flooding that’s created by heavy rainfall that can’t be quickly absorbed, such as flash floods.
In addition to sea-level rise, climate change is contributing to stronger storms and more flash flooding. Official flood maps have not kept pace with the increasing incidence of those events. As a result, Galster says, “We’re underestimating our danger by a big amount.”
As flood risks grow, both cities and states could consider policies that encourage denser development in less flood-prone areas. States will have to consider whether they can or should provide “last resort” property insurance, Galster says.
“Are [states] going to be prepared to help more and more thousands of people who are rendered homeless by these floods?” he asks. “Are they going to have to promulgate state-level building codes that look at where new buildings will or will not be permitted, and override local prerogatives?”
Complicated Picture on Racial and Income Disparities
The paper breaks down risks by state and differentiates between coastal and inland communities. Lower-income people are at greater risk of flooding in inland areas, but not in coastal communities. That could be partly explained by the demographics of coastal spaces. Even though they pose a greater risk of flooding, beachfront and coastal areas are highly desirable real estate.
Some lower-income places that have seen damage from hurricanes and floods are seeing spikes in real estate investment by wealthier people, as existing homeowners are unable to afford the increasing costs of repairs and maintenance. As a result, higher-income groups are disproportionately exposed to coastal flooding. “Nobody wants to be flooded out, but these groups can cover their losses a lot more readily,” Galster says.
His research finds that Native Americans in inland communities face higher risks of flooding than non-Hispanic whites nationally, especially in Iowa, Louisiana, North Carolina and Washington. It’s “a sizable disparity that we believe has been neglected” in the literature on environmental justice and flooding, the authors write. “It is clear … that Native American communities should be the focus of innovative programs for flood risk-transfer, property buyout and relocation subsidies, flood mitigation infrastructure and post-flood recovery support.”
Nationwide, the data show that non-Hispanic Black and Asian residents face lower flood risks than white communities. Galster admits the authors don’t have “a totally persuasive explanation” as to why this is the case. But they posit that Black and Asian households tend to be closer to the centers of metropolitan areas, which are often less flood-prone than outlying areas.
Although the paper explores how flood risks map onto racial demographics nationally, more granular local studies could help cities understand which groups of residents are most vulnerable to floods. “When it comes to racial inequities in exposure to flooding, it’s a frustratingly complicated and context-laden answer,” Galster says. “It’s really hard to make generalizations.”
