What is Cubic Feet per Second?
Cubic Feet per Second meaning (Abbrev. CFP) – In hydrologic terms, a unit expressing rates of discharge. One cubic foot per second is equal to the discharge through a rectangular cross section, 1 foot wide by 1 foot deep, flowing at an average velocity of 1 foot per second. It is also approximately 7.48 gallons per second.
reference: National Weather Service Glossary