A commonly used measure of water for the purposes of reservoirs and large-scale water use. One acre-foot is equal to one acre of water at a depth of one foot. In other words, one acre-foot equals 325,851 gallons of water, roughly half the size of an Olympic swimming pool.


Geologic formation that contains sufficient saturated permeable material to yield significant quantities of groundwater to wells and springs. The formation could be sand, gravel, limestone, sandstone or fractured igneous rocks.

Aquifer Storage and Recovery:

Aquifer storage and recovery (ASR) is the storage of water in a suitable aquifer through a well during times when water is available, and the recovery of water from the same aquifer during times when it is needed.


Maximum amount of raw water that could be produced by a source during a repeat of the Drought of Record, regardless of whether the supply is physically connected to or legally accessible by Water User Groups.

For more Regional Water Planning definitions, please see Chapter 357.10 of the Texas Administrative Code, found here.