Whitewater Flow Calculator

Evaluate river flow conditions for paddling suitability using flow rate, width, and depth to calculate velocity, Froude number, and feature suitability.

Inputs

Flow rate (cfs)

River width (ft)

Average depth (ft)

Feature Type

Tab to move between fields

Results

Flow velocity (ft/s)

2.78

Froude number0.28

Flow per ft width (cfs/ft)8.3

Feature suitability (0-100)28

Estimated whitewater class1

How to Use This Calculator

Look up the current flow rate in cfs from a USGS stream gauge for your river section.
Measure or estimate the average river channel width in feet at the feature you are evaluating.
Estimate the average water depth in feet across the channel.
Select the type of feature you are assessing: surfing wave, play hole, eddy lines, or general class run.
Read Flow Velocity (ft/s) and Froude Number — a Froude number above 1 indicates supercritical (fast, steep) flow.
Check Feature Suitability Score (0–100) and Estimated Whitewater Class to decide if current conditions match your skill level.

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