Flood Inundation Mapping (FIM) Program

Floods are the leading cause of natural-disaster losses in the United States. More than 75 percent of declared Federal disasters are related to floods, and annual flood losses average almost $8 billion with over 90 fatalities per year. Although the amount of fatalities has declined due to improved early warning systems, economic losses have continued to rise with increased urbanization in flood-hazard areas. The USGS Flood Inundation Mapping (FIM) Program helps communities protect lives and property by providing tools and information to help them understand their local flood risks and make cost-effective mitigation decisions.

The USGS Flood Inundation Mapping Program has two main functions:

1) Partner with local communities to assist with the development and validation of flood inundation map libraries.
A flood inundation map library is a set of maps that shows where flooding may occur over a range of water levels in the community’s local stream or river. The USGS works with communities to identify an appropriate stream section, gather the necessary data to model where flooding will likely occur, and verify that the maps produced are scientifically sound. To learn more about the scientific process of developing a map library, visit the FIM Science section.

Inundation maps can be used for:

• Preparedness - "What-if" scenarios
• Timely Response - tied to real-time gage and forecast information
• Recovery - damage assessment
• Mitigation and Planning - flood risk analyses
• Environmental and Ecological Assessments - wetlands identification, hazardous spill cleanup

To help communities create a flood inundation map library, the USGS created the FIM Toolbox, which contains development resources and contact information.

2) Provide online access to flood inundation maps along with real-time streamflow data, flood forecasts, and potential loss estimates.
Once a community’s map library is complete, it is uploaded to the USGS FIM Mapper, an online public mapping application. The FIM Mapper allows users to explore the full set of inundation maps that shows where flooding would occur given a selected stream condition. Users can also access historical flood information and potential loss estimates based on the severity of the flood. The FIM Mapper helps communities visualize potential flooding scenarios, identify areas and resources that may be at risk, and enhance their local response effort during a flooding event.

The USGS works with the National Weather Service, the U.S. Army Corps of Engineers, and the Federal Emergency Management Agency to connect communities with federal flood-related science thereby ensuring the quality and consistency of flood inundation maps across the country.

Partners: