Cubic metre per second or cubic meter per second in American English (symbol m3 ⋅ s−1 or m3/s) is the unit of volumetric flow rate in the International System of Units (SI).
It corresponds to the exchange or movement of the volume of a cube with sides of one metre (39.37 in) in length (a cubic meter, originally a stere) each second.
[citation needed] It is commonly used between workers in the measurement of water flow through natural streams and civil works, but rarely used in writing.
Data in units of m3 ⋅ s−1 are used along the y-axis or vertical axis of a flow hydrograph, which describes the time variation of discharge of a river (the mean velocity multiplied by cross-sectional area).
A moderately sized river discharges in the order of 100 m3 ⋅ s−1.