USGS National Streamflow Information Program
Status information in PDF format for easy printing.
The National Streamflow Information Program (NSIP) provides the Nation with streamflow information that is used for critical societal needs including the protection of life and property from floods, design of bridges and culverts, water resource management, aquatic habitat assessments, reservoir operation, and recreation safety and enjoyment. The USGS streamgage network is supported by four funding sources: the USGS Cooperative Water Program, the USGS NSIP, other Federal agencies (primarily the Corps of Engineers and Bureau of Reclamation), and 850 State and local funding partners (figure 1). The last two sources currently account for nearly 70 percent of the USGS streamgage network funding.
In 2008, the USGS operated about 7,600 streamgages. The number of active streamgages had been relatively constant since 1997 (figure 2). Because the streamgaging network depends heavily on partner interests and funds, there are often significant year-to-year changes in individual streamgages in operation causing instability in the network. While the network grew slightly in some parts of the Nation, other areas had significant numbers of important long-term streamgages being discontinued due to a lack of cooperator funds. Currently, there are 278 streamgages in 38 States either at risk of being discontinued or that already have been shut down since October 2009. The USGS has been unable to locate other funding partners to support these streamgages and has inadequate funds in the NSIP to maintain them. Not only are there a large number of streamgages being discontinued in some areas, but those streamgages can also account for a substantial percentage of the network in that area. There is a vast amount of information accumulated through the records of these streamgages. The longest period of record for these at risk streamgages is 114 years, with many others having 70 to over 100 years of record. For a list of the currently at risk streamgages, see the USGS web page: http://streamstatsags.cr.usgs.gov/ThreatenedGages/ThreatenedGages.html.
Network instability has important implications because the loss of long record streamgages reduces the potential value of streamflow information for infrastructure design applications and environmental assessments. Long records of streamflow are vital to the characterization of regional hydrologic conditions (for purposes of water supply planning and flood hazard assessments) as well as for documenting and understanding changes that occur in streamflow due to changes in land use, water use, groundwater development, and climate. From 1995 to 2008, 948 critical streamgages with 30 or more years of record were discontinued. In FY 2007 and 2008 alone, 210 critical long record streamgages were discontinued.
The federal funding for USGS programs supporting streamgaging is shown in Figure 3. NSIP received a $5.0M funding increase in 2010 and the President has proposed no funding increase in 2011. The 2010 increased funds have been used to help stabilize the streamgaging network and support climate change evaluations. The Cooperative Water Program (CWP) received a $1.2M increase in 2010 and the President has proposed no increase for 2011. The graphs in Figure 3 show the funding trends for these two programs over the past decade. The NSIP is currently funded at about 20 percent of planned full funding.
The USGS continues to make great advances in upgrading streamgages with near real-time data delivery capabilities (figure 2). Over 89 percent of all USGS streamgages have telemetry (satellite, radio, or phone) and now deliver data to users in near real-time via the World Wide Web. NSIP is also investing resources into long-term improvements in the overall delivery of streamflow information to users. These improvements include: database enhancements to streamline the computational process and to improve user's access to real-time and historical streamflow information, new assessment methods to define trends and estimate streamflow at ungaged locations, and research and development to measure streamflow more accurately, less expensively, and more safely. Some specific advances recently incorporated into the USGS streamgaging program include: (a) the use of non-contact radar sensors to measure river stage in special conditions; (b) the use of acoustic Doppler technology to measure streamflow more quickly, more accurately, and under extreme flow conditions and in difficult measuring locations; (c) the use of new software (the Graphical Ratings and Shift Application Tool (GRSAT)) to develop and maintain rating curves, enhancing streamflow data quality, and reducing labor hours; and, (d) upgrades to high data rate satellite telemetry radios at over 3,000 streamgages. For more information on recent improvements, see "U.S. Streamflow Measurements and Data Dissemination Improve", EOS, v. 85, No. 21, May, 2004 or http://water.usgs.gov/osw/pubs/EOS-Streamflow.pdf and "Recent Improvements to the U.S. Geological Survey Streamgaging Program", FS2007-3080 (http://pubs.usgs.gov/fs/2007/3080/).
The National Academy of Sciences review of the USGS's plan for the NSIP (located at http://www.nap.edu/books/0309092108/html) concluded the NSIP was "a sound, well conceived program that meets the nation's needs for streamflow measurement, interpretation, and information delivery" (The National Academy of Sciences, 2004, Assessing the National Streamflow Information Program).
The National Hydrologic Warning Council completed an independent, two phase, cost/benefit analysis of the USGS streamgage program. Phase one evaluated the wide range of uses of USGS streamflow information. The second phase analysis, which focused only on streamflow information benefits for flood protection concluded that "…the benefit clearly exceeds the estimated cost of operating and maintaining the network." The reports describing their evaluations are available at the National Hydrologic Warning Councils webpage: http://nhwc.udfcd.org/publications.htm.
For additional information on the National Streamflow Information Program, contact the program coordinator, J. Michael Norris, email@example.com, 603-226-7847, or visit http://water.usgs.gov/nsip/.