cfs
cubic foot per second
Volumetric flow rateexact by definition
The cubic foot per second is exactly 0.028316846592 cubic metres per second, about 28.3 L/s or 449 US gpm. It is the unit of surface water hydrology in North America: stream gauging, flood flows, culvert design and water rights are all in cfs.
Watch out: One cfs sustained for a day is 1.983 acre-feet, which is why the western water world calls it a "cfs-day" and treats the near-2 relationship as a rule of thumb.
| 1 cfs | 1,699.0108 L/min |
Where the unit came from
Also called the cusec, and in western US water law the "miner's inch" was defined as a fraction of one, varying by state, which is a good illustration of what happens when a unit is written into statute rather than into physics.
Solvers that use volumetric flow rate