Flood Inundation Mapper

Posted on: 7/31/2017 - Updated on: 2/27/2020

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The USGS Flood Inundation Mapper is an online flood mapping tool. Once a community develops a flood inundation map library through a collaborative effort with USGS, inundation maps are uploaded to the web-based mapper for broader viewing and access. Users can select a specific location and explore several different data sets, including current stream conditions, the estimated extent of historic flood events, and theoretical flooding scenarios. The current conditions data page gives a snapshot of current flood risk: it charts stream flow gauge height over the past four days, provides a prediction of stream gauge height over the upcoming 4 days, and identifies a flooding threshold at which agency “action” may be required. Users can also explore inundation patterns for historic flood events, or map theoretical inundation events by adjusting stream gauge height to model different flood levels. Spatial flooding extent for historic and theoretical events is mapped onto a user-decided base layer, with choices including topographical and street maps, allowing users to identify areas and assets that are vulnerable to different flood stages. The USGS mapper also provides and maps potential loss estimates for various flood scenarios. Users can analyze how building and vehicle loss changes with flood severity (as well as the spatial distribution of these losses), the amount and type of debris a flood may generate, and what sort of shelter requirements a city or county would need to provide to accommodate displaced citizens. Data from the mapper can be downloaded, and users can register for alerts for sites of interest. The USGS Flood Inundation Mapper can be used by various agencies and stakeholders to visualize and prepare for a variety of flood scenarios by identifying assets and areas most at risk. Information from the flood mapper can be integrated into a variety of planning efforts for both municipalities and natural resource managers.

Phase of Adaptation: Awareness, Assessment, Planning


Land managers, water utility managers, natural resource managers, local authorities, planners, policymakers, engineers, scientists, public


U.S. Geological Survey (USGS)

Managing Organizations

The USGS is a science organization that provides impartial information on the health of our ecosystems and environment, the natural hazards that threaten us, the natural resources we rely on, the impacts of climate and land-use change, and the core science systems that help us provide timely, relevant, and useable information.