Peak-flow frequency analyses for selected streamgages in Dawson and Richland Counties, and the Powder River Basin, Montana, based on data through water year 2022

The USGS Wyoming-Montana Water Science Center (WY–MT WSC) completed a report (Sando and McCarthy, 2018) documenting methods for peak-flow frequency analysis following implementation of the Bulletin 17C guidelines. The methods are used to provide estimates of peak-flow quantiles for 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (AEPs) for selected USGS streamgages. This data release presents peak-flow frequency analyses based on methods described by Sando and McCarthy (2018), for selected streamgages in Dawson and Richland Counties, and the Powder River Basin, based on data through water year 2022.