This unit represents exactly 43,560 cubic feet, or roughly 326,000 US gallons. Hydrologists, reservoir operators, and irrigation engineers use it to quantify large bodies of water because it translates easily to land area and rainfall depth. It provides a more intuitive scale for municipal water supply and agricultural usage than millions of gallons.
Heard on the job
The reservoir level dropped again this week, and we're down another four hundred acre-feet since the last survey.
Insider tip
When speaking to the public, water managers often use the rule of thumb that one acre-foot equals the annual water usage of two to three suburban households.