Where can I find flood maps?
FEMA is the official public source for flood maps for insurance purposes:
- FEMA’s Flood Map Service Center
- FEMA’s National Flood Hazard Layer
NOAA is responsible for producing flood forecast maps that combine precipitation data with USGS streamflow data:
- NWS - National Water Prediction Service: River forecasts and long range flood outlook
- Coastal Inundation Dashboard: Real-time and historical coastal flooding information
USGS flood map products include:
- USGS Flood Information: Maps and resources for current and historical floods.
- Flood Inundation Mapper: Shows where river flooding might occur over a range of water levels. Only available for a few areas.
- Flood Event Viewer: Data collected during short-term flood events like hurricanes and multi-state storms. Includes rapid-deployment gages, temporary sensors, and high-water marks.
- Coastal Change Hazards Portal: Extreme storms, shoreline change, and sea-level rise.
Related
Filter Total Items: 17
Estimating the magnitude and frequency of floods at ungaged locations on urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina, using data through the 2022 water year Estimating the magnitude and frequency of floods at ungaged locations on urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina, using data through the 2022 water year
In 2024, the U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, updated the methods for predicting the magnitude and frequency of floods at ungaged locations on streams in urban areas in Tennessee. The study area included 136 streamgages in urban areas in Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina that had at least 10...
Authors
Daniel M. Wagner, David E. Ladd
Flood-inundation maps for Río Grande De Loíza in and near Caguas, Puerto Rico, 2026 Flood-inundation maps for Río Grande De Loíza in and near Caguas, Puerto Rico, 2026
Digital flood-inundation maps for a 2.7-mile reach of Río Grande De Loíza in Caguas, Puerto Rico, were created by the U.S. Geological Survey. Water-surface profiles were computed for the stream reach by using a one-dimensional, steady-state, step-backwater model. The model was calibrated to the current (2025) stage-streamflow relation (rating curve) for the U.S. Geological Survey...
Authors
Chad J. Ostheimer, Legna M. Torres-Garcia, Julieta M. Gomez-Fragoso
Flood-inundation maps for Río de la Plata in and near Comerío, Puerto Rico, 2025 Flood-inundation maps for Río de la Plata in and near Comerío, Puerto Rico, 2025
Digital flood-inundation maps for a 3.1-mile reach of Río de la Plata in and near Comerío, Puerto Rico, were created by the U.S. Geological Survey (USGS). Water-surface profiles were computed for the stream reach by using a one-dimensional steady-state step-backwater model. The model was calibrated to the current (2025) stage-streamflow relation (rating curve 11.0) for the USGS...
Authors
Chad J. Ostheimer, Legna M. Torres-Garcia
How USGS gages are used in flood forecasting How USGS gages are used in flood forecasting
The U.S. Geological Survey (USGS) operates an extensive nationwide network of stream, rain, and groundwater gages. These instruments are used to monitor how much water there is across the Nation at any given moment. Stream data are collected at streamgages every 15 minutes, transmitted to USGS servers, and updated online in real time. To improve awareness of current water conditions and...
Authors
Steven Sobieszczyk
Guidelines for determining flood flow frequency — Bulletin 17C Guidelines for determining flood flow frequency — Bulletin 17C
Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including...
Authors
John F. England, Timothy A. Cohn, Beth A. Faber, Jery R. Stedinger, Wilbert O. Thomas, Andrea G. Veilleux, Julie E. Kiang, Robert R. Mason,
Field manual for identifying and preserving high-water mark data Field manual for identifying and preserving high-water mark data
This field manual provides general guidance for identifying and collecting high-water marks and is meant to be used by field personnel as a quick reference. The field manual describes purposes for collecting and documenting high-water marks along with the most common types of high-water marks. The manual provides a list of suggested field equipment, describes rules of thumb and best...
Authors
Toby D. Feaster, Todd A. Koenig
Related
Filter Total Items: 17
Estimating the magnitude and frequency of floods at ungaged locations on urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina, using data through the 2022 water year Estimating the magnitude and frequency of floods at ungaged locations on urban streams in Tennessee and parts of Alabama, Georgia, Mississippi, North Carolina, and South Carolina, using data through the 2022 water year
In 2024, the U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, updated the methods for predicting the magnitude and frequency of floods at ungaged locations on streams in urban areas in Tennessee. The study area included 136 streamgages in urban areas in Tennessee, Mississippi, Alabama, Georgia, South Carolina, and North Carolina that had at least 10...
Authors
Daniel M. Wagner, David E. Ladd
Flood-inundation maps for Río Grande De Loíza in and near Caguas, Puerto Rico, 2026 Flood-inundation maps for Río Grande De Loíza in and near Caguas, Puerto Rico, 2026
Digital flood-inundation maps for a 2.7-mile reach of Río Grande De Loíza in Caguas, Puerto Rico, were created by the U.S. Geological Survey. Water-surface profiles were computed for the stream reach by using a one-dimensional, steady-state, step-backwater model. The model was calibrated to the current (2025) stage-streamflow relation (rating curve) for the U.S. Geological Survey...
Authors
Chad J. Ostheimer, Legna M. Torres-Garcia, Julieta M. Gomez-Fragoso
Flood-inundation maps for Río de la Plata in and near Comerío, Puerto Rico, 2025 Flood-inundation maps for Río de la Plata in and near Comerío, Puerto Rico, 2025
Digital flood-inundation maps for a 3.1-mile reach of Río de la Plata in and near Comerío, Puerto Rico, were created by the U.S. Geological Survey (USGS). Water-surface profiles were computed for the stream reach by using a one-dimensional steady-state step-backwater model. The model was calibrated to the current (2025) stage-streamflow relation (rating curve 11.0) for the USGS...
Authors
Chad J. Ostheimer, Legna M. Torres-Garcia
How USGS gages are used in flood forecasting How USGS gages are used in flood forecasting
The U.S. Geological Survey (USGS) operates an extensive nationwide network of stream, rain, and groundwater gages. These instruments are used to monitor how much water there is across the Nation at any given moment. Stream data are collected at streamgages every 15 minutes, transmitted to USGS servers, and updated online in real time. To improve awareness of current water conditions and...
Authors
Steven Sobieszczyk
Guidelines for determining flood flow frequency — Bulletin 17C Guidelines for determining flood flow frequency — Bulletin 17C
Accurate estimates of flood frequency and magnitude are a key component of any effective nationwide flood risk management and flood damage abatement program. In addition to accuracy, methods for estimating flood risk must be uniformly and consistently applied because management of the Nation’s water and related land resources is a collaborative effort involving multiple actors including...
Authors
John F. England, Timothy A. Cohn, Beth A. Faber, Jery R. Stedinger, Wilbert O. Thomas, Andrea G. Veilleux, Julie E. Kiang, Robert R. Mason,
Field manual for identifying and preserving high-water mark data Field manual for identifying and preserving high-water mark data
This field manual provides general guidance for identifying and collecting high-water marks and is meant to be used by field personnel as a quick reference. The field manual describes purposes for collecting and documenting high-water marks along with the most common types of high-water marks. The manual provides a list of suggested field equipment, describes rules of thumb and best...
Authors
Toby D. Feaster, Todd A. Koenig
Updated Date: September 30, 2026