Imagine you have a pipe 22' across and 500' long. Connected to the end of the pipe is a large pump capable of moving 1,140,000 gallons of water every minute (152,000 cubic feet of water per minute). How can you determine how fast the water will flow in the pipe? Actually, it is very easy to calculate. All you have to do is divide the pump capacity by the cross-sectional area of the pipe.