Tuesday, October 04, 2005

Outdated FEMA Flood Maps Put Millions At Risk

FEMA Information - Legislative Actions:

FEMA's flood maps are dangerously out of date and terribly unreliable.
[July 12, 2005] Experts from across the country testified before a House Subcommittee that FEMA’s billion dollar map modernization program was digitizing obsolete data. FEMA testified that in many cases maps do not necessarily change over time.

Experts unanimously agree that floodplains change over time as a result of land clearing associated with development, erosion, and other factors. FEMA’s maps have an average age over well over ten years, with some experts claiming the average age is eighteen years. One expert testified to “garbage in, garbage out” in regards to the modernization program.

To anyone working in a government GIS office (at least in the Midwest) this shouldn't be a surprise. When a county or local government digitizes a new dataset for parcels, streams or any other feature, the data is never encouraged to be distributed to any other agency let alone a central source. There is little to no communication between agencies or varying levels of government.

Wouldn't it be nice if there was a REAL, LIVE repository of the most current GIS datasets (vector and raster)? Even if each state put together there own web service that enabled this it would be a significant start.

Often this type of discussion gets bogged down in details of metadata and standards compliance. My opinion - get something operational now and work out the details later. Hell, set up an FTP server at the state level that allows public AND private entities to upload/download their own and other datasets. A basic solution CAN be done on the cheap without requiring everyone to have a web guru on staff.

In August 2005, Congress moved to freeze FEMA's flood mapping efforts.
House appropriators took the action because they said they were misled by officials. The lawmaker said the program was "originally portrayed as a means to update all of the nation's flood maps."

The department last year began updating 25,000 of the 100,000 maps with geographic information systems and posting them on the Internet. Seventy percent of the maps are more than 10 years old, according to the Government Accountability Office.

A 2004 GAO report found that the maps become outdated because of property development that can cause erosion and changes in drainage patterns of rainwater.

The GIS technology would let FEMA meld different types and sources of data by linking multiple digital databases and graphically displaying layers of information on the Internet. GAO said an example includes layers of a map of all the streets in a specified area, on top of the area's topography or elevation data, and aerial photographs and streams in the same area.

"These themes are all key elements needed to create flood maps that accurately depict floodplains and can be used to identify properties in these areas," GAO said. FEMA said it also would use light detection and ranging remote-sensing technologies to collect highly detailed and digital elevation data.

ABC News did a story tonight on how these garbage maps resulted in tens of thousands of home owners in New Orleans NOT getting flood insurance (and subsequently losing everything).
Based on those maps, residents of parts of St. Bernard Parish in Louisiana were told that they did not need federal flood insurance. They lived in sections of the parish that fall outside FEMA's designated Flood Hazard Area.

FEMAinfo.us has a tremendous amount of information and detailed links on how FEMA's flood mapping operation is truly a disaster in it's own right.


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