Developing a Flood Monitoring Network in Pennsylvania

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Water information is fundamental to national and local economic well-being, and to the protection of life and property. The USGS streamgage network is the largest in the U.S. and collects stream water levels from more than 10,000 streamgages nationwide. 

Even with almost 400 streamgages in Pennsylvania, there is still a need for additional data collection at unmonitored locations during flooding. Water levels and associated data at both gaged or ungaged streams and rivers during and after major storm events help 

• determine impact areas from severe flooding, 
• assist with emergency management decisions, 
• support risk assessment, and 
• inform future mitigation efforts.

Flood Data Collection in Pennsylvania, a web geonarrative, describes the compilation of available data related to flood hazards. An interactive web mapper, Pennsylvania Bridge Over Water Locations Being Considered for Flood Data Collection, helped select sites for the flood network. Geospatial data includes: 

• locations of bridges over water,
• scour-critical bridges,
• densely populated areas,
• historical hurricane tracks,
• historical flood event data collection sites,
• counties with historical disaster declarations,
• Social Vulnerability Index data, and
• aggregated flood-related disaster data provided by FEMA:
  • insurance claims, 
  • individual assistance applications, and 
  • repetitive loss records. 

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Using the geonarrative, 50 sites across Pennsylvania were chosen to be included in the network. Field reconnaissance was conducted at each of the sites, to select the best suited flood sensor for the site conditions and survey local elevations of interest. Elevations of local points of interest, including bridge decks, road intersections, walking paths, and parking lots, were surveyed. Use of these elevation data in the USGS Real-Time Flood Impact Map helps convey immediate flood risks. Water level data are displayed in the USGS Flood Event Viewer and USGS Water Data For the Nation. In April 2026, USGS scientists deployed water level sensors at 26 flood network locations across Pennsylvania. A total of 22 of these provide data in near real-time. A table of the currently deployed sensors within the Pennsylvania Flood Network is provided below. 

USGS PAWSC Rapid Deployment Network Location Table

Last updated: 9/21/2026

[BRKEY, Pennsylvania Department of Transportation bridge identifier number}