River Difficulty Rating Calculator
Estimate whitewater class (I-VI) from river gradient, flow rate, channel width, obstacle density, and water temperature.
Inputs
Results
Whitewater class (I-VI)
4
Difficulty score (0-100)45.6
Gradient contribution16
Flow per ft width (cfs/ft)16
Cold water risk score5.5
Suggested experience (years)5
Class LabelIV — Advanced
How to Use This Calculator
- Look up the river gradient (ft per mile) from topo maps or guidebooks — Class II is ~10 ft/mile, Class IV is ~40–60 ft/mile.
- Check a USGS gauge for current flow rate in cfs and enter it.
- Enter the average navigable channel width in feet.
- Select obstacle density from few/none through very dense based on your scouting or guidebook description.
- Enter the water temperature in °F — cold water raises the consequence rating and overall difficulty.
- Read Whitewater Class (I–VI) and Suggested Experience (years) to match the run to your skill level.
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