Headwaters Economics has conducted an analysis of flood and socioeconomic data to illustrate where flood risks disproportionality affect vulnerable populations.

Floods both expose and reinforce inequities. Over 53 million people in the United States live in high flood risk areas, but certain groups – such as people of color and Hispanics, mobile home residents, and people with disabilities – are more likely to be impacted by a flood than others.

A community’s vulnerability to flooding is based on its exposure to rising water, its infrastructure, local government capacity, and people’s ability to prepare for, respond to, and recover from a flood event – often referred to as social vulnerability.

Socially vulnerable groups tend to have more exposure to flooding and be disproportionately impacted in the short and long terms.  

In a new analysis, we find:

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The unequal impacts of flooding are well documented, yet hard to change. Historic economic, political, and land use decisions have led to certain groups facing higher risk while also having less ability to access resources and less power to advocate for changes. Compounding these vulnerabilities, disaster recovery systems in the United States have been shown to further reinforce patterns of inequities and unequal access to resources.

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Headwaters Economics has conducted an analysis of flood and socioeconomic data to illustrate where flood risks disproportionality affect vulnerable populations, especially in lower-capacity communities where local governments face challenges in planning and executing disaster mitigation projects. In the interactive map below, one can filter counties by flood risk, community capacity, and demographic characteristics of populations that may be particularly vulnerable to floods. This tool can help identify places that need more resources, technical assistance, and long-term investments to address flood risk and protect community members.

Too many local governments lack the staff and resources they need

Local governments are largely responsible for investing in and maintaining projects to decrease flood risk, but not every community has the time, staff, and resources needed to proactively plan and implement projects that can decrease flood risk. Analyses of federal funding for mitigation projects demonstrate that lower-capacity communities are less likely to access climate resilience funding.

Land use, infrastructure, and other government decisions impact flood risk, such as the amount of impervious surface and deferred maintenance on stormwater and wastewater systems. Unincorporated communities and other places that lack local government resources face additional complications to disaster management and emergency response.

State policies and government capacity also shape local communities’ ability to plan for, respond to, and recover from flooding. However, state flood resilience policies vary, including the extent to which they focus on equity and social vulnerability.

How to address the unequal impacts of flooding

Disaster policies too often fail to account for the impacts faced by vulnerable populations, but there are positive steps that can be taken at the federal, state, and community levels.

Prioritize people and wellbeing in disaster policies, rather than property losses. Many disaster policies are focused on property values, damage assessments, and repair costs. As a result, high-income places often receive more attention and resources. Disaster policies and programs that prioritize social vulnerability metrics such as impacts to affordable housing or low-income people would lead to more equitable outcomes.

Limit administrative burdens. Reducing the time and expertise needed to access resources can help create more equitable outcomes. For instance, instead of using the current application process for disaster recovery aide, FEMA could switch to categorical eligibility, which would mean people impacted by disasters would automatically qualify for assistance.

Proactively fund projects that address the root causes of social vulnerability. Addressing flood risk can have complementary benefits for communities. Flood mitigation projects in places that have a history of disinvestment can be designed to also deliver improved water, wastewater, and/or stormwater infrastructure. Investments that build community wealth by addressing flood risk and social inequality are key for building long-term resilience.

Target communities and regions with high flood risk and limited government capacity. Many communities with high flood risk and social vulnerabilities lack the staff, resources, and expertise needed to implement solutions. Federal agencies and technical assistance providers should prioritize working in these regions with a focus on strengthening local government capacity, with particular attention to the potential of regional solutions.

Data sources & methods

Flood risk data

First Street Foundation provided flood data from their Flood Factor platform for use in this research. Flood risk is defined as the percent of properties within each county that have a >1% chance of a flood in a given year. We rank each county’s flood risk relative to the entire nation:

  • Very High: > 90th percentile (higher flood risk than 90% of U.S. counties)
  • High: > 75th percentile
  • Medium: > 50th percentile
  • Low: ≤ 50th percentile (lower flood risk than 50% of counties in the U.S.)

Socioeconomic data 

The socioeconomic variables are from U.S. Census Bureau’s American Community Survey (ACS). Data are from the latest release of the ACS five-year estimates (2017-2021). These estimates represent data collected over the five-year period. The primary advantage of using multiyear estimates is the increased statistical reliability of the data for less-populated areas and small-population subgroups.

ACS is a survey of residents with reported margins of error based on the number of respondents. The margin of error as reported by ACS is displayed in the mouse-over tooltip for each county.

The variable “People of Color and Hispanics” is the difference between the Total Population estimate and the estimate for “non-Hispanic” people that also self-identified as “White alone.”

Data about community capacity are from Headwaters Economics’ Rural Capacity Map.                       

How to cite this research

The unequal impacts of flooding. 2023. Headwaters Economics. Bozeman, MT.

Kris Smith, Ph.D.

  kris@headwaterseconomics.org       802.989.5385

Kristin “Kris” Smith, Ph.D., is the Lead Researcher for Headwaters Economics’ FloodWise Community Assistance program. Her research on hazards, natural resources, and rural economic development is informed by her on-the-ground work with local governments and technical experts helping communities reduce flood risk.