Gauge Description:

Paddlers have historically referred to a stage reading taken from the Hwy.23 bridge. However, with USGS gauges now online, confusion arises because the gauges do not directly correlate. In an effort to modernize and standardize, the more accurate and unmistakable gauge (cfs) reading will be used here.

Translation between paddlers "bridge gauge" and the USGS 'Sandstone gauge' is roughly -3 feet. Bridge gauge levels above 2' (5.2' on USGS) are runnable, though many paddlers will suggest better play begins at 4' on the bridge (6.72' on USGS).

A somewhat more detailed statistical analysis of the data suggests the following conversion:
23 Bridge Level = ( 1.31 x Internet Sandstone Level ) - 4.8

"Maximum" as given here (2300 cfs) is only an indication of a level above which the character of the run will change from 'friendly play' to more pushy and having more consequence. The river is runnable much higher, with the understanding that holes will become 'keepy', and undercuts will become dangerous (deadly).

A local boater suggests the following ratings:

These are conservative ratings. At levels over 2300 CFS (4 feet bridge gauge), the undercuts become active, drawing the class IV ratings.