Regression equations for selected streamflow statistics based on data through water year 2021 in and near Wyoming

The U.S. Geological Survey (USGS), in cooperation with the Wyoming Water Development Office (WWDO), developed streamflow statistics regression equations using basin characteristics and streamflow statistics at streamgages for mean daily discharge data through water year 2021. This data release provides supplementary data to the Scientific Investigation Report (SIR), "Methods for Estimating Selected Streamflow Statistics at Ungaged Sites in Wyoming Based on Data through Water Year 2021" (Taylor and Sando, 2026).
These data include a table of regression equations for 243 streamflow statistics (regression_equations.xlsx). The statistics are mean annual maximum, mean annual, mean seasonal, and mean monthly streamflows; n-day statistics: M7D2Y, M7D10Y, M14D5Y, M30D5Y, V60D2Y, and V1D5Y; and the 0.1-, 0.2-, 0.5-, 1-, 2-, 4-, 5-, 10-, 20-, 25-, 30-, 50-, 60-, 70-, 75-, 80-, 90-, 95-, 98- and 99-percent durations for annual streamflows and 0.1-, 0.5-, 10-, 15-, 20-, 25-, 30-, 40-, 50-, 60-, 70-, 75-, 80-, 85-, 90-, 95-, and 99-percent duration for monthly streamflows. These data include a table of streamgages used in developing the regression equations (used_streamgages.csv) and a table of streamgages omitted from developing the regression equations (unused_streamgages.csv). Details on streamgage selection are in the accompanying SIR. Also included is an Excel file (covariance_matrices.xlsx) containing the regression covariance matrices, which are used to calculate the confidence and prediction intervals for the respective streamflow statistics estimated at ungaged sites. A data dictionary is included to describe the attribute information in the covariance matrices Excel file (data_dictionary.csv).