USGS Water Resources Information

Provisional Data Information

Note: these USGS Illinois WSC real-time data web pages use an older interface and eventually will be replaced by the USGS national real-time data web pages located at http://waterdata.usgs.gov/il/nwis/rt. Please update any bookmarks to use the national real-time data pages. If you have any questions, please email gs-w-il_NWISWeb_Maintainer

Real-time data from streamflow-gaging stations are transmitted to the USGS, Illinois District office in Urbana through telephone lines or through the Geostationary Operational Environmental Satellite (GOES) data-collection system. Data are transmitted from each station at intervals of between 1 to 3 hours and are loaded onto the Illinois District computer system.

Real-time data available on the Illinois Water Resources pages are provisional, which means they have not been reviewed or edited. These data may contain significant errors and are not citeable until reviewed and approved by the U.S. Geological Survey. For example, stage data may have errors due to a malfunction of the sensing or recording equipment. Discharge data may contain errors because the stage-discharge relation used to compute discharge may be in error as the result of the following:

Data users are cautioned to consider carefully the provisional nature of the data before basing decisions utilizing the data that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences.

Data are reviewed and corrected periodically to ensure accuracy. Data from station record are considered provisional until they are published. The data are usually published within 6 months of the end of the water year (Sept. 30). Shortly after that time, the published data will be made available on these pages as historical data.

Information concerning the accuracy of these data or concerning other hydrologic data may be obtained from:

John LaTour
Hydrologist
U.S. Geological Survey
Illinois Water Science Center
1201 W. University Ave.
Urbana, IL 61801
(217) 344-0037 ext.9723
<jklatour@usgs.gov>
<-- Go to the Illinois NWIS-W Data Retrieval page
<-- Go to the Illinois Water Resources page
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Comments and questions are welcome! Please email gs-w-il_NWIS-W_Data_Inquiries@usgs.gov.

Department of the Interior, U.S. Geological Survey, Illinois Water Science Center
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