July 2, 2004

Much of southern Michigan set new records for the total amount of rainfall in May, and many southern Michigan communities experienced flood damage to homes and businesses. Nationally, flooding is recognized as the most costly natural hazard, causing greater loss of life and property than all other natural hazards combined. Over 10 million homes and commercial buildings are located in floodplains, and managing and limiting development in these areas is the most practical and effective means of preventing loss of life and property.

Floodplain regulations restrict development to elevations at or above the base flood elevation, defined as a flood event having a 1 percent chance of being equaled or exceeded in any given year. This has commonly become known as the "100-year flood." This approach has helped to keep development out of harm’s way, and has helped minimize loss of life and property damage.

Smaller floods can also cause damage, such as a 5-year flood event, a 10-year flood event, and a 25-year flood event, where there is a 20 percent, a 10 percent, and a 4 percent chance respectively of having an equal or greater flood occurring in a given year. The Department of Environmental Quality floodplain engineers estimate that the May flood events were generally in the range of a 5- to 10-year flood across most of southern Michigan; a 25-year flood for the Huron River at Hamburg, Livingston County; and a 50- to 100-year flood for the North Branch of the Clinton River in Macomb County.

The May 2004 floods were unfortunate events that demonstrated to residents in floodplain areas how susceptible lives and properties are to flooding. Actions to mitigate future flood impacts to residential and commercial structures include structure relocation outside of the floodplain, elevating structures above the site specific 100-year base flood elevation, or various flood-proofing measures. Federal financial assistance may be available in some areas.

One simple action that some residents located within floodplain areas can take is to obtain flood insurance for their buildings and contents. This insurance is available to all citizens living in communities that participate in the National Flood Insurance Program (NFIP). This program, administered by the Federal Emergency Management Agency, provides flood insurance at reasonable cost in exchange for floodplain development management commitments by participating communities. Standard homeowners and commercial property policies generally do not cover flood losses.

Citizens living in a community not participating in the NFIP are encouraged to discuss this with their local officials and support them in becoming NFIP participants.

Persons or communities interested in learning more about the NFIP can contact Les Thomas, NFIP State Coordinator, DEQ, P.O. Box 30458, Lansing, Michigan 48909, (517) 335-3448, thomasl@michigan.gov or access the NFIP website at www.fema.gov/fima/nfip.

Editor’s note: DEQ news releases are available on the department’s Internet home page at www.michigan.gov/deq.

Revised July 2, 2004 by Pat Watson