More than 282,500 Indiana homes, businesses and other structures are at substantial risk of flooding, about 67 percent more than the government currently estimates, according to a recent study.
That study calculates that 113,600 Indiana propertiesthat are not currently in a mapped floodplain are at risk of flooding,representing an enormous potential cost to homeowners and the government alike.
Many neighborhoods across the state, from Mishawaka and South Bend to Indianapolis are particularly vulnerable, according to the analysis.
The problem, researchers say, is that Federal Emergency Management Agency floodplain maps are sometimes based on decades-old data, whereas global warming and urbanization have changed rainfall and drainage patterns. Updating the maps would be expensive, but not doing so could have dire consequences as cities approve construction in flood-prone areas.
Updating the maps could also erode property values in areas added into a 100-year floodplain, and put the burden of flood insurance on some families — at an average of $1,000 per year in Indiana.
Historically, people of color and people with low incomes are more likely to live in a floodplain, said Johnson, who does flood risk modeling for the state of Louisiana.
This is partially because when it comes time for a community to protect a population from flooding by investing in a levy, dam or otherwise, the project has to prove the protection's benefits will outweigh the costs of building it. Because more affluent communities have higher property values, they are more likely to be protected by preventive floodplain investments, he said.
Communities of color are also working against decades of marginalization in cities that compound their susceptibility to environmental events like flooding, said Elizabeth Browning, an environmental historian at Indiana University.
"When it comes to flooding, many communities of color do not have access to functioning sanitation infrastructure," Browning said. "In cities like Indianapolis, local government officials and public health departments have not historically devoted sufficient resources to shore up decaying sanitation systems, with excess rainfall and river overflows leading to significant public health problems."