In 2026 the National Geodetic Survey is releasing the North American-Pacific Geopotential Datum of 2022. This will have a wide range of implications on how we collect and disseminate spatial data. This session is an introduction to the new datum and its parts as well as discussion of how it will impact USGS Water systems and interpretive data.
This session will focus on a new tech memo from the NGS (NOS NGS 92). I will present the changes in field survey methods the NGS has outlined in the document and discuss potential changes to USGS GNSS data collection methods to bring us into compliance.
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.
