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Why might USGS streamflow data be revised?

Real-time USGS streamflow data are PROVISIONAL, meaning that the data have not been reviewed or edited. These data might be subject to significant change and are not official until reviewed and approved by the USGS.

Real-time streamflow data can be affected by:

  • backwater from ice or debris such as log jams
  • algae 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.

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

Learn More: Streamgaging Basics