Great Lakes Coastal Flood Hazard Studies

Federal Emergency Management Agency logoThe Federal Emergency Management Agency (FEMA) has initiated a coastal analysis and mapping study to produce updated Digital Flood Insurance Rate Maps (DFIRMs) for coastal counties around the Great Lakes. This storm surge study is one of the most extensive coastal storm surge analyses to date, encompassing coastal floodplains in eight states. Ultimately, the study will update the coastal storm surge elevations for all of the U.S. shoreline of the Great Lakes. This new coastal flood hazard analyses will utilize updated 1-percent-annual chance stillwater elevations obtained from a comprehensive storm surge study conducted by the U.S. Army Corps of Engineers.

An updated coastal flood study will provide a better estimate of coastal flood hazards and risk for the Great Lakes. The current, or effective, Flood Insurance Rate Maps (FIRMs) are outdated primarily due to the age of data and methodologies, many of which date back to the 1970s. Major changes in National Flood Insurance Program (NFIP) policies and methodologies have occurred since the effective dates of many Flood Insurance Studies (FIS) in the area, creating the need for an update that would reflect a more detailed and complete hazard determination. For more information, please visit

Public outreach is an important of the study. Meetings were held with officials from each coastal community and interested members of the public to provide information on the study and to solicit existing data that could be used. FEMA calls this process "Discovery", and documents the results in a report.

FEMA's Discovery Reports provide users with a comprehensive and holistic understanding of historical flood risk, existing coastal data, and current flood mitigation activities within each lake's basin. The Discovery Report also provides users with a summary of FEMA's intent to proceed with a coastal flood hazard study under FEMA's Risk Mapping, Assessment, and Planning (Risk MAP) program and the Great Lakes Coastal Flood Study (GLCFS) project.

To view or download a Discovery Report, click on a lake from the following list (or scroll down):

Lake Erie
Lake Michigan
Lake St. Clair
Lake Huron - anticipated in 2013
Lake Superior - anticipated in 2013

Click the links below to open the documents; right-click and select "Save As…" to download the documents to your computer.


Lake ErieRisk Assessment, Mapping, and Planning Partners logo

The basin-wide final draft Discovery Report for Lake Erie is available at the Great Lakes Coastal Flood Study Web Site.

A 45-day public comment period on the final draft report will close on January 27, 2013.  Any comments on the draft report should be provided to


Lake MichiganStrategic Alliance for Risk Reduction logo

The final draft Discovery Report for Lake Michigan is available at the Great Lakes Coastal Flood Study web site.  The final draft includes all Michigan communities along the Lake Michigan shoreline.

A 45-day public comment period on the final draft report will close on January 11, 2013.  Comments can be sent to


Lake St. ClairStrategic Alliance for Risk Reduction logo

A 45-day public comment period for this final draft report closed on November 30, 2012.