Background: A decrease in the number of streamgaging stations and a disapportionate loss of streamgaging stations with long-term records, together with an increasing demand for streamflow information, led Congress to request an evaluation of the U.S. Geological Survey's streamgaging network's ability to meet the streamflow information needs of the Nation. A November 1998 report to Congress concluded that for five national goals evaluated, the ability of the network to meet the goals was declining and had been for the last 10 to 20 years. The decline was attributed to the absolute loss in the number of streamgaging stations and the USGS's declining ability to continue operating high-priority stations when partners discontinue funding. The report also stated that new and changing issues have greatly increased the demand for streamflow information, and that new technologies are needed to support the network to improve the reliability of the data, decrease costs, and decrease uncertainty of the information the network provides.
Major components of the National Streamflow Information Program (NSIP): The National Streamflow Information Program is a vision of the infrastructure that the USGS believes is needed to meet the streamflow information requirements of the Nation. This plan proposes methods to increase the quantity and quality of streamflow information, to improve the way streamgaging stations are funded and located, and new ways to collect, store, and distribute streamflow information. NSIP consists of five major components:
1. Enhanced nationwide streamgaging network (Federal-Interest Streamflow Network):
There would be a Federal-interest network of stations that would be operated by the USGS even in the absence of support of funding partners. It would include about 5,300 stations to meet five critical Federal goals funded entirely by Federal appropriation. The fixed costs of the total USGS streamgaging program (about 40% of total network costs) also would be funded by Federal appropriation, but the marginal costs for all other streamgaging stations would be funded by partners (including cost sharing under the Cooperative Water program). The following table shows the number of stations needed to meet the critical Federal goals, how well the network in 1996 met the goal, and the number of additional stations required to fully meet the goal.
Critical Federal Interest |
Number of sites or reaches to be served |
Level of attainment in 1996, in percent |
Number of additional streamgaging stations needed to meet goal |
Flows across State lines |
350 |
56 |
160 |
NWS Flood-Forecast Sites |
3100 |
66 |
1100 |
Flows from key river basins |
350 |
57 |
150 |
Sentinel Watersheds |
800 |
58 |
350 |
Water Quality |
700 |
76 |
320 |
TOTAL |
2,080 | ||
Note: Some of the figures above have been updated as of July 2000 from Open-File Report 99-456. | |||
2. Intensive data collection during major floods and droughts:
Additional information would be collected to better characterize major floods and droughts. This additional information would include systematic field surveys of precipitation, river stage, and river discharge; the installation of temporary streamgages during events; opportunistic sampling of sediment, nutrients, bacteria, pesticides, and hydrocarbons; and characterization of changes in geomorphology of river channels and reservoir sedimentation.
3. Streamflow information would be interpreted on regional and national scales:
A permanent program of systematic streamflow analysis and interpretation would be established. Regional assessments would be done within physiographic provinces over a period of 10 years. A national assessment would be done every 10 years. The streamflow characteristics analyzed and evaluated would include mean and median flows, flood and low-flow characteristics, seasonal cycles, and evaluations of long-term trends. Information from the assessments would be fed back into network design process. The goal would be to estimate flow characteristics at any site on any stream with a low standard error.
4. Enhanced streamflow information delivery and products:
A new data base system would be designed and implemented which provides backup computer and communication mechanisms for reliable data delivery. Stage and discharge information would be available at the time resolution that it was collected at (15-, 30-, or 60-minutes). Data presented also would have uncertainty bounds associated with it. User specified formats and statistics would be available for unified historical and current data.
5. Methods development and research:
New and emerging technologies for streamflow measurements will be identified, evaluated, and developed as appropriate. This will provide for safer and less-costly data collection in the future. Current needs are for non-contact stage and discharge measurement capabilities, techniques for streamgaging error estimation, dynamic models for continuous streamflow estimation, new methods for flood frequency, trend analysis, and regionalization, and models for real-time inundation mapping of flood risk areas.