NWDTW 2024

Annual peak streamflow data from USGS streamgages are a critical dataset engineers and hydrologists use for flood frequency analyses that inform bridge designs, floodplain maps, and other projects in and along rivers. Updated Federal guidelines for flood-frequency analysis (Bulletin 17C) were released in 2019, which allow for better use of information published by the USGS, such as censored (greater than or less than) data, and data sources outside of streamgage records, such as historic peaks. In this workshop, attendees will learn how annual peak-flow data are used, what peak flow qualification codes mean and when to use them, what flood information should be included in station descriptions and manuscripts in SIMS, the proper application of “highest since” notes to annual peaks, proper treatment of peak flows at crest-stage gages, and lots of other flood-related facts. An example streamgage will be analyzed with the PeakFQ software to demonstrate application of USGS data to a real-world flood-frequency problem.