Streamgaging Network

When planning for a flood, there are three key questions that must be answered:  What areas will be flooded? How deep will the floodwaters get? When will the flood arrive? A flood inundation map library is a set of maps that together show where flooding may occur – and how deep it may be - over a range of potential flooding scenarios in a stream or river.

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.

For more than a century, Canada and the United States have maintained a system of monitoring streamflow and water levels for shared waters. Today, the USGS and Environment and Climate Change Canada (ECCC) maintain a network of International Gauging Stations and International Support Gauging Stations that are determined to be mutually beneficial to both agencies.

Federal Priority Streamgages (FPS) are automated stations that monitor water conditions in streams and rivers throughout the country. Originally established in 1999, these are important for meeting specific long-term needs of the Nation. The FPS Network was recently re-prioritized which resulted in size of the network increasing to nearly 12,400 locations.

To manage our water resources effectively, we need to understand how much water is available and its usefulness. The USGS monitors the nation’s water resources through various national observing networks that use a range of technologies and methods to assess real-time water conditions and predict future changes in water availability for human and ecological uses.

Regional Water Availability Assessments are scientific assessments of water availability in different hydrologic regions across the Nation. They are designed to capture a range of conditions in major drivers of water availability.

The USGS Water Resources Mission Area is assessing how much water is available for human and ecological needs in the United States and identifying where and when the Nation may have challenges meeting its demand for water.

As of October 2024, the USGS Groundwater and Streamflow Information Program supports the collection and (or) delivery of both streamflow and water-level information at 8,705 sites and water-level information alone at 3,460 additional sites. The data are served online—most in near real-time—to meet many diverse needs including the protection of life, property, the environment, and our economy.

Centennial Streamgages are USGS streamgages that have been in operation for more than 100 years.

The Willamette River Basin reflects the conflicting water demands between humans and ecosystems—particularly salmon— and the challenge resource managers face throughout the Pacific Northwest.

Get the facts and figures about the USGS Streamgaging Network, one of the largest streamgaging enterprises in the world!

Get access to spatial datasets related to water through the NSDI node on ScienceBase.