By way of background on those maps, the National Flood Insurance Program (NFIP) makes flood insurance available for properties in participating communities – Ann Arbor is a participant. If a building has a federally-backed mortgage and it’s located within the “1% annual change floodplain” (previously called the “100-year floodplain) then flood insurance is required.

Ann Arbor’s most recent FIRM dates from Jan. 2, 1992. In 2004, the Federal Emergency Management Agency (FEMA) began a map revision process for Washtenaw County. Various drains in the city were re-analyzed, using updated data, and on July 27, 2007, FEMA issued preliminary maps. After required public review, appeal and revisions, on Oct. 3, 2011, FEMA issued a letter with a final determination, indicating that the new maps would become effective on April 3, 2012. [.pdf of Oct. 3, 2011 letter] [.pdf of Dec. 20, 2011 reminder letter]

Compared to the previous 1992 maps, 321 parcels are no longer analyzed as lying within a floodplain. However, 116 parcels that were previously not analyzed as in a floodplain are now in a floodplain, according to the new maps. Building-wise, 452 structures are no longer analyzed as lying within a floodplain, while 88 buildings are now in a floodplain, according to the new maps. [See also Chronicle coverage: "Column: Digital Information Flood."]

This brief was filed from the city council’s chambers on the second floor of city hall, located at 301 E. Huron. A more detailed report will follow: [link]