Streamflow Information Program

Science Center Objects

The U.S. Geological Survey (USGS) operates and maintains a national network of about 8,000 streamgages (2018) to provide long-term, accurate, and unbiased streamflow information (often called discharge) to meet the multiple needs of many diverse users. Streamflow information is fundamental to national and local economic well-being, protection of life and property, and efficient and effective management of water resources. Long-term streamflow information is critical for use in water management, computation of flood and drought flows for water infrastructure, and analysis of climate-related trends. The USGS operates the national streamgaging network in partnership with more than 850 federal, state, tribal, regional, and local agencies. (Hodgkins and others, 2014)

For more information visit Groundwater and Streamflow Information Program.

The National Streamflow Information Program (NSIP), now (2019) the Groundwater and Streamflow Information Program (GWSIP), was started in 2002 in response to Congressional and stakeholder concerns about the ongoing decrease in the number of active USGS streamgages (particularly streamgages with long periods of record), the inability of the USGS to fund high-priority streamgages when faced with reduced partner funds, and the increased demand for streamflow information via the Internet beginning in the late 1980s.

The NSIP had five major goals:

1. Develop, maintain, and fully fund an enhanced, stable baseline streamgaging network that meets Federal needs for streamflow information, including the need for long-term datasets. This baseline network is supplemented by streamgages funded by partnerships to meet state, regional, and local needs.

2. Improve the timeliness, reliability, and convenience of streamflow information delivery to users. This includes robust and redundant data delivery systems that ensure continued availability of data during catastrophic events and provide improved storage, retrieval, and data analysis abilities.

3. Make regional assessments of existing streamflow information on an ongoing basis to identify trends and to estimate streamflow at locations without streamgages. These trend analyses can help to identify the effects of land-use, water-use, and climatic changes.

4. Improve the understanding of floods and droughts through additional measurements and analyses.

5. Perform and fund research and development activities to advance equipment technologies and measurement and analysis techniques for greater accuracy and lower cost.

Implementation of the USGS next-generation water observing systems under the Groundwater and Streamflow Information Program (GWSIP) will take NSIP to new heights. The Delaware River Basin pilot provided an opportunity in 2018 to develop the next-generation observing system in a nationally important, complex interstate river system. 

First streamflow records on the San Juan River near Bluff, Utah, were made using a chain gage (directly below horses) in 1914.

First streamflow records on the San Juan River near Bluff, Utah, were made using a chain gage (directly below horses) in 1914.

(Public domain.)

Consistent with the NSIP and GWSIP, the Utah Water Science Center partners with about 40 entities and operates about 150 gages throughout Utah.  Changes in technology since 1915 have catapulted the collection of streamflow data into the next century and beyond. One hundred years ago it took days, first by train and then by horse, just to reach the remote San Juan River gage near Bluff, Utah. Today, streamflows at this gage and elsewhere, are updated every hour via satellite and are accessible to anyone in the world with internet access.  

RC Pierce makes a measurement at the San Juan near Bluff, Utah gage in 1915 from hand-hewn cable car

RC Pierce drew the short straw and was assigned to the San Juan River gage near Bluff, Utah in 1915. This Utah station had the distinction of being the most isolated station in the country. It was 180 miles from the nearest railroad station. Pierce is making a measurement from a hand-hewn cable car using a 60-pound solid-lead weight he cast in Salt Lake City. The weight was attached to an improvised wooden reel (similar to a yacht steering wheel) 4 feet in diameter. (Image was reproduced from a glass slide discovered in Utah Water Science Center collections. The black frame was part of the slide. (Public domain.))


San Juan River gage near Bluff, Utah 2017

San Juan River gage near Bluff, Utah, 2017. Today, radar is used to measure stage of river (left) and measurements are made from an all-aluminum cable car using Acoustic Doppler Current Profiler (ADCP) technology. (Public domain.)