What is CFS on a river gauge?
CFS vs gauge height
Most USGS gauges report both numbers, and they answer different questions. Gauge height (stage, in feet) is how high the water surface sits above a local reference point — it is what flood stages are based on. Discharge (CFS) is how much water is moving.
For anything other than flood thresholds, CFS is usually the more useful of the two, because it is comparable in a way gauge height is not. Height depends on an arbitrary datum chosen when the gauge was installed, so “4.2 ft” means nothing unless you already know that specific gauge. Most run descriptions and fishing reports are therefore written in CFS. More detail in how to read a river gauge.
Why there is no universal “good” CFS
A flow that is perfect on one river is unrunnable on another. 300 cfs might be a great level on a small technical creek and barely a trickle on a wide river. Channel width, gradient, and bed shape all change what a given volume of water does.
That means flow ranges are always per run. The reliable sources are a local outfitter, a regional guidebook, or a community database such as American Whitewater, which publishes recommended ranges for specific stretches. Once you have the range for your run, the live gauge tells you where today sits within it.
The more useful question: high or low for the season?
A raw CFS value does not tell you whether a river is running unusually high or low — that depends entirely on what is normal for that river at that time of year. 800 cfs could be a spring low or a late-summer flood on the same gauge.
This is exactly what our streamflow conditions map shows. Each gauge is ranked against roughly ten years of its own daily record for the same week of the year, so a gauge is labelled from “extremely low” through “normal” to “extremely high” relative to its own history. It is the fastest way to answer “is this river running well right now?” without knowing the river.
A note on safety
Flow numbers inform a decision; they do not make it. Higher discharge means faster water, more force, and fewer places to stop, which raises the consequences of any mistake — but strainers, low-head dams, cold water, and changing weather are dangerous at any level. Get local knowledge for the run, and if a river is at or above flood stage, it is not a recreation question at all.
Frequently asked questions
What does CFS mean on a river gauge?
CFS is cubic feet per second — the volume of water passing the gauge each second. One cubic foot is about 7.5 gallons, so 1,000 cfs is roughly 7,500 gallons per second. It measures how much water is moving, while gauge height measures how high the surface sits.
What is a good CFS for kayaking?
There is no universal number. A good flow is specific to each run — 300 cfs can be ideal on a small creek and far too low on a big river. Use the run description from a local outfitter, guidebook, or American Whitewater for that specific stretch, then check the live gauge against it.
Is CFS or gauge height more useful for paddling?
CFS is usually more comparable, because most run descriptions and trip reports are written in cubic feet per second. Gauge height depends on an arbitrary local datum, so a height reading only means something if you already know that gauge.
How do I know if today's flow is high or low for the season?
Compare it with the gauge's own history rather than a raw number. The streamflow conditions map on this site ranks each gauge against about ten years of its own record for the same week of the year, so you can see whether flow is well below normal, normal, or unusually high.
Does higher CFS always mean more dangerous?
Higher flow generally means faster water, more force, and fewer places to stop, which raises the consequences of a mistake. But hazards depend on the specific run — strainers, low-head dams, and cold water are dangerous at any flow. Flow numbers inform a decision; they do not make it.
Check flows now
See how flows compare with normal across the country, or find gauges near you.