Keeping vacant, flood-prone lands free of development could save taxpayers billions, according to conservation scientists.
In a study published this week in the journal Nature Sustainability, the Nature Conservancy, University of Bristol and other institutions found that every $1 spent acquiring undeveloped properties in the 100-year floodplain — which have a 1% chance of flooding in any given year — returns $5 that would be spent on emergency services, flood insurance claims and other flood damage costs if those properties became developed.
As the number of people living in flood-prone regions like St. Louis is increasing, local governments should consider protecting undeveloped floodplain properties instead of building on them, said Barbara Charry, the floodplain and nature-based solutions strategy manager for the Nature Conservancy’s Missouri chapter.
“We’ve had over [recent] years, three floods of record, on the Meramec, Mississippi and Missouri rivers,” Charry said. “We can avoid flood damages by protecting natural areas and preventing them from being developed.”
Many local governments, however, may not have the money to buy flood-prone land, said Kris Johnson, the study’s lead author and deputy director of agriculture at the Nature Conservancy.
“It also could be through something relatively simple and cheap: stronger and better-enforced zoning regulations that really curtail and direct development outside of these areas at risk,” Johnson said.
The Nature Conservancy is working with the Army Corps of Engineers to develop a plan to improve floodplain management for the eight municipalities along the lower Meramec River.
The paper’s findings bolster positions that environmental groups have taken against developing low-lying areas in the St. Louis region. Many municipalities don’t consider the long-term costs of building in the floodplain, said David Stokes, executive director of the Great Rivers Habitat Alliance.
“You have elected officials, often part-time, suburban, elected officials — the only thing they’re capable of looking at is increasing sales tax dollars for their city,” Stokes said. “It’s been incredibly damaging. Not only have all these subsidies [for floodplain development] hurt the tax base of the region, not resulted in any true economic or job growth, flooding is worse in St. Louis because of all the flood-plain development that’s done here.”
Stokes recently opposed the city of Maryland Heights’ plan to create a tax incentive finance district to build pumps and levees in an area near the Missouri River. Developers want to build homes, businesses and other kinds of development there that will only push water to other communities and increase flood damages, he said.
Development in St. Louis County could raise the flood risk for communities across the Missouri River in St. Charles County, 40% of which is in the floodplain. The Maryland Heights proposal could affect every taxpayer, just as the Chesterfield Valley development has, said St. Charles County Executive Steve Ehlmann.
“Within Chesterfield, there are 316 properties with $147 million of federally backed flood insurance. If [the Monarch] levee ever breaks or if a terrorist blows a hole in it, the taxpayers are automatically on the hook for $147 million,” Ehlmann said.
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