Provisional Streamflow Data

Surface-water and water-quality data from real-time streamflow gages are relayed to the Oregon Water Science Center Office in Portland through an automatic data-collection system. Data are transmitted from each station at intervals of 3-6 hours and are loaded onto the USGS computer system.

Real-time data are 'provisional' and have not been reviewed or edited. These data may be subject to significant change and are not official until reviewed and approved by the collecting agency. Real-time streamflow data may be changed after review because the stage-discharge relationship may have been affected by:

• backwater from ice or debris such as log jams
• algal and aquatic growth in the stream
• sediment movement
• malfunction of recording equipment

Data are reviewed periodically to ensure accuracy. Each station record is considered provisional until the data are published. The data are usually published within 6 months of the end of the water year; the water year starts October 1st and ends September 30th.

Data users are cautioned to consider carefully the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences.