Flood Inundation Mapping (FIM) Program

Science Center Objects

Floods are the leading cause of natural-disaster losses in the U.S. 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 continue to rise with increased urbanization in flood-hazard areas.

Screenshot of new USGS Flood Inundation Mapper from a mobile phone

Screenshot of the new mobile-friendly USGS Flood Inundation Mapper. This screenshot was taken during Minor Flooding Stage (National Weather Service) in St. Paul, Minnesota, on April 7, 2020.

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.


Flooding on the Baraboo River, Wisconsin

Flooding on the Baraboo River, Wisconsin. (Credit: Chuck Dunning, USGS)

History of the USGS Flood Inundation Mapping (FIM) Program

2002: Washington State Dynamic Snoqualmie Model Report - First FIM library with on-demand mapping during a flood event. FloodPath's dynamic mapping is only turned on during events. 

2007: North Carolina Tar River lidar derived FIM report - First project to detail the lidar processing needed to support flood inundation mapping and document the standard FIM methodology 

2008: Midwest floods spark a discussion about starting a uniform USGS FIM initiative 


  • April - First preliminary FIM website, guidance, and templates released online 
  • June - First FIM coordination meeting in Atlanta. The FIM Mapper is launched with the Findlay, Ohio, library. The prospectus outlining the FIM Program is finalized 
  • Fall - FIM Toolbox is released with guidance documents 
  • December - Second FIM Coordination meeting in Louisville 

2011 (January): USGS Scientific Investigations Map template is distributed via the Toolbox. FIM becomes a National Program with Office of Surface Water leadership 

2012 (November): Started working with the National Weather Service and the U.S. Army Corps of Engineers on an interagency FIM requirements team, Integrated Water Resources Science and Services (IWRSS). The first regional FIM team is formed in the Midwest Area (remaining regional teams formed in 2013). 

2013 (December): FIM Program Strategic meeting 


  • May - SIR Template is released via the Toolbox 
  • June - National FIM Strategic Planning meeting 

2015: February - Release of USGS FIM Policy Memorandums and updated FIM Toolbox 

Beloit, Wisconsin flood of June 2008

Photo of Rock River, looking west-southwest, June 21, 2008. (Credit: Allan Brillman)