Flood Risk AreasBuildings located in many low lying areas of the Great Lakes have been repeatedly damaged by coastal flooding. In Michigan, coastal floods periodically result in millions of dollars of property loss to homes and businesses. State and local government facilities and operations are also severely affected by flooding and post flood recovery costs. Approximately 300 miles of Michigan's Great Lakes mainland is subject to coastal flooding. Although flooding is a natural, inevitable event, severe flood damage is avoidable.
The flood risk area program requires new construction in the 100- year floodplain of the Great Lakes to be elevated to prevent property damage. The 100-year flood is defined as a flood that has a one percent chance of being equaled or exceeded in any year. It does not mean that a flood of this size only happens every 100 years; such a flood could occur more than once in a 12 month period. Forty-one coastal communities have designated flood risk areas mapped and regulations in effect. These designated communities have approved zoning ordinances and regulate construction in flood risk shorelands locally. The Department periodically monitors performance and provides technical assistance.