This can only be calculated once the length of the pipe in question has been established.
This pipe will hold 23,500.7 gallons of water.
100 feet by 100 feet by one inch equates to 6,233.76 gallons of water.
There are 22.85 gallons in a waste line which is 2 inches in diameter and is 140 feet long. This can be calculated as pi * r *r *length *7.48051 where r and length are both expressed in feet. (pi = 3.14159265).
100 feet of 3-inch pipe holds 36.73 gallons of water.
About 235 gallons of water.
22.44 gallons for each inch of the water's depth.
12,239.9 gallons of water per 3,000 feet.
5.5 gallons per 15 feet of 3-inch pipe.
111 gallons of water.
14.7 gallons of water.
A 72-inch pipe 16 feet long holds up to 3,384.1 US gallons of water.
You would need 2,451 feet of 2-inch pipe for 400 gallons.