The question, as stated, cannot be answered sensibly. A gallon is a measure of volume, with dimensions [L3]. A square foot is a measure of area, with dimensions [L2]. The two measure different things and basic dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information.
There are approximately 1.34 million cubic feet in 90 million gallons.
That's simple arithmetics: 14 million gallons per day is 14 million gallons per 86400 seconds, so it's about 162 gallons per second. 162 gallons is about 21.66 cubic feet. Divide that by the area of channel section of 500 square feet and you get about 0.043 feet/second.
1 acre = 43,560 square feet1 million acre-feet = (106) x (43,560) x (1) = 4.356 x 1010 cubic feet = 325,851,428,600 gallons (rounded)
None ... gallons is a measurement of volume, square feet is area not volume.
You cannot convert a measure of area (square feet) to a measure of volume (gallons). Gallons is a measure of volume, or of 3 dimensions. You'd need cubic feet (not square feet) to convert it to gallons.
400 Square Feet.
There are zero gallons in any number of square feet, as square feet have no distance in the tird dimension to qualify a volume.
280.298 Imperial gallons
Water volume of 35.2 km3 (28,500,000 acre·ft)----- 28.5 million acre-feet x 43,560 square feet in an acre = 1.24 trillion cubic feet x 8.1 (gallons in a cubic foot) = 10 trillion gallons
4.5 million square feet = about 0.161 square miles.
There are 144 square feet in 2000 gallons, assuming you are asking about surface area coverage. This can vary based on how you are spreading the gallons (e.g., on soil, on a floor).
1 million gallons per day equates to about 0.001522472 cubic feet per second.