Water School

What is an acre-foot?

An acre-foot is commonly used to measure water volume. It is the amount of water needed to cover one acre (43,560 square feet) with one foot of water. One acre-foot is equal to 325,851 gallons of water, enough to cover a football field with a foot of water.

Measuring acre footage is an important way to calculate the volume of large water resources, like irrigation sources, reservoirs, sewers, canals, and human-made lakes, such as Possum Kingdom Lake, which is located in Palo Pinto, Jack, Young, and Stephens counties.

This water supply reservoir holds about 540,000-acre-feet of water and almost half is available as water supply for the Brazos River basin. With 230,750-acre-feet available for water supply, it is important to measure any changes in the amount of water available. 

Without a tool to measure the volume of water, it would not only be difficult to know how much water is in an area, but it would also make it hard for organizations like the Brazos River Authority from acting proactively to prevent water loss. 

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The information provided on this site is intended as background on water within the Brazos River basin. There should be no expectation that this information is all encompassing, complete or in any way examines every aspect of this very complex natural resource.

If you have questions about a post or would like additional information, please contact us or call 888-922-6272.

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