Stream-Gaging Program of the U.S. Geological Survey
Reston, Virginia, 1995
By Kenneth L. Wahl, Wilbert O. Thomas, Jr., and Robert M. Hirsch


The U.S. Geological Survey (USGS) stream-gaging program provides streamflow data for a variety of purposes that range from current needs, such as flood forecasting, to future or long-term needs, such as detection of changes in streamflow due to human activities or global warming. The development of data on the flow of the Nation's rivers mirrors the development of the country. From the establishment of the first stream-gaging station operated by the USGS in 1889, this program has grown to include 7,292 stations in operation as of 1994. Data from the active stations, as well as from discontinued stations, are stored in a computer data base that currently holds mean daily-discharge data for about 18,500 locations and more than 400,000 station-years of record. The stream-discharge data base is an ever-growing resource for water-resources planning and design, hydrologic research, and operation of water-resources projects.

More than 600 State, Federal, and local agencies provide funding for the stream-gaging program. More than 50 percent of the 7,292 stations operated by the USGS are funded through the Federal--State Cooperative Program whereby the USGS provides up to 50 percent of the funds and the State or local agency provides the rest. The USGS provides full support for fewer than 10 percent of the stations that it operates.

The uses of streamflow data are described, and the growth of the stream-gaging program is related to legislation and the need to manage the Nation's water resources better. The dynamic nature of the stream-gaging program is illustrated by noting the changes in the program from 1981 through 1986 and from 1985 through 1994.

A brief description is provided of techniques for measuring stage and discharge, computing streamflow records, and disseminating the data through published reports and electronic media. A brief history is provided of the nationwide evaluations of the stream-gaging program that were undertaken to ensure that the program was keeping abreast of changes in objectives and technology and meeting the needs of the data users. Finally, challenges for the future are identified. These challenges include maintaining a long-term and consistent data base, upgrading the stream-gaging structures and equipment, providing ready access of streamflow data to users, and training and maintaining a skilled staff to operate the stations in the stream-gaging program.

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