Municipalities Increasingly Ignoring FEMA Flood Risk Maps, Drawing Their Own
In flood-prone regions of the country, a growing number of cities have lost confidence in the ability of the federal government's flood maps to recognize the increasing risks that come with global warming. From Houston to Baltimore to Cedar Falls, Iowa, and now Mexico Beach, Florida, local officials are going beyond the federal standards and have started to require homes in a much wider area—beyond the usual 100-year floodplain—to be built to higher flood-protection standards.
In Mexico Beach, the move was triggered in part by the Federal Emergency Management Agency's decision to reclassify dozens of properties that flooded last year in Hurricane Michael. The homes had been in the high-risk 100-year flood zone, where flood insurance generally is required, but FEMA moved them to the minimal-risk 500-year flood zone, where flood insurance is optional. The city's goal is to have more homes and businesses higher and drier, so they're less likely to suffer flood damage when the next storm hits.
Hundreds of communities and as many as 22 states already require new construction be elevated higher than federal requirements in the high-risk 100-year floodplain, which is based on a 1 percent chance of flooding in any given year. Now, a small but growing number of cities and counties are also extending the additional building-height standards to the wider 500-year floodplain.
Officially, the 500-year floodplain means a 0.2 percent annual chance of flooding, but climate change may be loading the dice for higher risks. "We now are seeing this trend start because people are getting these extreme events," said Larry A. Larson, a professional engineer and senior policy advisor for the national Association of State Floodplain Managers.
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https://insideclimatenews.org/news/19032019/fema-flood-maps-risk-zones-cities-climate-change-mexico-beach-houston-outer-banks
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