1980s FEMA Flood Maps Not Remotely Adequate For Sandy, And FEMA Knew It Beforehand
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The flaws in the maps had significant impact. Developers relied on FEMA's assessment of risks when they built new homes near the water. And homeowners and businesses made crucial decisions about where to buy or lease property on the assurance that they were outside of the high-risk zones. Thousands of the buildings incorrectly identified as outside the flood zone were damaged when seawater surged ashore as Hurricane Sandy made landfall on Oct. 29, 2012.
State and city officials had been asking FEMA for years to revise the maps with technology and modeling methods that didn't exist when they were first drawn in the 1980s. William S. Nechamen, New York State's floodplain chief, warned FEMA in a 2005 letter that the failure to do so "will lead to higher than necessary flood damages and more expenses placed on individuals and on FEMA."
Yet, despite Nechamen's warning, FEMA missed chances to make changes that could have protected city dwellers from some of the worst of Sandy's destruction.
During a push to modernize flood maps in the mid-2000s, FEMA decided to save money in New York City and much of the rest of the country by digitizing old flood maps without updating the underlying information, rather than using new technology to create more accurate maps.
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http://www.climatecentral.org/news/federal-flood-maps-left-new-york-unprepared-for-sandy-and-fema-knew-it-16826