Streamflow regressions, daily mean streamflow estimates, and annual and monthly streamflow statistics for Clearwater River tributaries in Central Idaho

The U.S. Geological Survey (USGS), in cooperation with the Nez Perce Tribe, used streamflow measurements at 12 ungaged, partial-record sites and developed relationships with nearby USGS real-time streamgages (index sites) to provide daily mean streamflow values at partial-record sites in the Clearwater River basin. Daily mean streamflow was estimated by developing a regression relationship between streamflow at each partial-record site and the index site for the period of record of the index site. The regressions are then used to estimate annual and monthly mean, median, and 80-percent exceedance probability streamflow at each partial-record site for the last 30 water years (1994 to 2024). The daily mean and monthly streamflow statistics at partial-record sites will support the Nez Perce Tribe's effort to monitor streamflow in previously ungaged basins.