How many gallons are in one acre-foot of water?

One acre-foot of water is defined as the amount of water that covers one acre of land to a depth of one foot. To understand why the correct answer is 325,850 gallons, it helps to break down the units involved in an acre-foot measurement.

An acre is equivalent to 43,560 square feet. When you fill this area to a depth of one foot, you are effectively filling it with a volume of water equal to 43,560 cubic feet. Since there are approximately 7.48 gallons in a cubic foot, the total number of gallons in one acre-foot can be calculated as follows:

1. Multiply the number of cubic feet by the number of gallons per cubic foot:

43,560 cubic feet × 7.48 gallons/cubic foot = 325,851 gallons.

This calculation shows that one acre-foot is indeed about 325,850 gallons when rounded to the nearest whole number, which matches the correct answer provided. This understanding is particularly important in irrigation, water resource management, and environmental studies, where knowing the volume of water over a specific land area is crucial for planning and conservation efforts.