Knowing the conversion factor between GPM and MGD is only half the job — a process control operator also needs to move fluently through longer conversion chains (GPM to MGD to CFS and back) and, critically, needs to turn a velocity reading and a pipe size into an actual flow number. This guide puts the Q = VA equation to work with real pipe dimensions, building directly on the geometry you've already covered for circular cross-sections.
Full Conversion Chains
You already know the GPM ↔ GPD ↔ MGD relationships from the fundamentals level. Now add CFS (cubic feet per second) to the chain, which requires converting between gallons and cubic feet.
The key conversion factor: 1 cubic foot = 7.48 gallons (this comes from the geometry of a cubic foot combined with the definition of a gallon, and is one of the most-used constants in this field — worth memorizing).
CFS to GPM:
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