noun
a unit of volume commonly used in the United States in reference to large-scale water resources, equal to the volume of water needed to cover one acre of land to a depth of one foot
The reservoir has a capacity of 10,000 acre-feet of water.
The lake can hold about 10,000 acre-feet of water.
That dam can store a whole bunch of acre-feet.
Her love for him was as deep as an acre-foot of water.