The State of Vermont issued its first hydraulic geometry report in 2001 and then did a follow-up report in 2006 with a focus on smaller streams. For both reports, I took a look at the data and tried to add a bit more analysis (2001 review and 2006 review) and I offered some critiques to the reports.
One aspect that surprised me upon closer inspection of the USGS measurement data were how few overbank measurements were made. The USGS has a very well established protocol on stream measurements and rating curve development. All of that is great, but at some point, even the best made curves do start to become and extrapolation at higher flows. While I can fully appreciate staffing and resource limitations, as well as very legitimate safety concerns, it did surprise me that in some cases, several feet of stage change were essentially an educated and professional judgement guess for the associated discharge during high flow runoff events.
With respect to hydraulic geometry curves, this link is one I check perhaps 3 or 4 times a year to see if there are any updates, particularly for my area of interest in New England.