The unit, decoded
What is CFS, really?
Every river gauge in the country reports in cubic feet per second. Picture a box one foot on each side — a basketball fits inside with room to spare — filled with water. One CFS means one of those boxes sweeps past you every second.
Turn any reading into things you can picture
| Every second | — | gallons |
|---|---|---|
| Every second | — | basketballs' worth |
| Every minute | — | backyard hot tubs (400 gal) |
| Every hour | — | Olympic pools (660,000 gal) |
Rough reference points
| CFS | What that volume tends to mean |
|---|---|
| 50 | Small-creek volume — tubes drag gravel in the shallow spots. |
| 300 | A modest floatable river's summer pace on many curated reaches here. |
| 1,500 | A full, businesslike river — the water is doing the paddling. |
| 10,000 | Big-river volume: think the Deschutes or lower Shenandoah with momentum. |
| 100,000+ | Flood-scale flow on most rivers people float. Nobody's floating. |
The same CFS reads differently in different channels — width, depth, and gradient decide the feel. That's why every river page here compares a reading with that river's own history, never with a universal scale.
Common questions
How many gallons is 1 CFS?
One cubic foot holds about 7.48 gallons, so 1 CFS is 7.48 gallons every second — about 449 gallons a minute, or roughly 646,000 gallons in a day. A garden hose runs around 0.02 CFS; a fire hose, about 0.3.
Is 300 CFS a lot of water?
It depends entirely on the channel it's squeezed into. 300 CFS spread across a wide, shallow gravel bed is a lazy drift; the same 300 CFS pinched between boulders is a fast chute. That's why RiverDates always frames a reading against the same river's own history instead of calling any number big or small.
What's the difference between CFS and gauge height?
Gauge height (stage) is how deep the water is at one measuring point, in feet; CFS is how much water is moving past it. Stage is local — a sandbar shift can change what three feet means — while CFS travels: it's the number flow records, forecasts, and this site all share.