Developing reliable upper-end extensions of stage-discharge rating curves is often challenging due to limited high-flow measurements. This presentation outlines a clear hierarchy of preferred approaches—starting with direct flow measurements, followed by indirect methods—and then focuses on practical in-office techniques that can be performed without field work. Methods include estimating peak flows using areal regression (Q vs. drainage area), transferring peak discharges from upstream or downstream gages, and leveraging the StreamStats cross-section cutting tool along with the AreaComp3 software program to generate control and channel geometry. These desk-based strategies allow hydrologists to effectively vet rating descriptor pairs, assess curve shape, and confidently extend ratings to higher stages.
