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Banking Water Now for Arizona's Future

Water Storage

Recharge and Recharge and Facilities


What is Recharge?


Direct recharge is the process of flooding an area and allowing water to percolate down through the soil, replenishing underground aquifers. In the future, the recharged water can be pumped out with recovery wells for use in meeting demand. The Arizona Water Banking Authority participates in direct recharge by partnering with operators of recharge projects to store excess CAP supplies at those facilities.

Indirect recharge or in lieu recharge is the process of using renewable surface water supplies instead of groundwater to irrigate farmland. The reduction in groundwater pumping results in allowing groundwater to remain in the aquifer and is referred to as "groundwater savings". The Arizona Water Banking Authority participates in indirect recharge with the agricultural community using CAP water as the alternative surface water supply.

Long-term storage credits are accrued by the Arizona Water Bank through permitted facilities that store water either through direct recharge or indirect recharge. The added volume in the aquifer creates the credit. Credit is given for water that reaches the aquifer (3-5% delivery loss) minus the 5% cut to the aquifer.

In 1986, the Arizona Legislature established the Underground Water Storage and Recovery program to allow persons with surplus supplies of water to store that water underground and recover it at a later time for the storer's use.  In 1994, the Legislature enacted the Underground Water Storage, Savings, and Replenishment Act which further defined the recharge program.  The recharge program is administered by the Arizona Department of Water Resources (ADWR).  Additional information on recharge and the permitting process can be found at ADWR's website.


Types of Facilities


The Arizona Water Bank stores water at two types of facilities: Underground Storage Facility (USFs) and Groundwater Savings Facility (GSFs).


An Underground Storage Facility (USFs) is a facility that physically stores water in the aquifer through direct recharge. The most common type of recharge project uses infiltration (spreading) basins in which water is spread out over a large surface area and water infiltrates or seeps into the alluvial material eventually reaching the aquifer. These areas are typically located adjacent to stream channels where infiltration rates are high due to the porous nature of the soils. Another type of recharge project involves the use of injection (recharge) wells where water is forced directly into the aquifer through the borehole of the well. This recharge method is less common than infiltration basins because of its higher operational expense. Both infiltration basins and injection wells are categorized as Constructed USF's since they use some type of constructed device to operate.

The other type of USF is called a Managed USF where water is discharged into a streambed and allowed to flow naturally down the channel without the assistance of any construction. Water infiltrates (percolates) into the aquifer below the stream channel.

A Groundwater Savings Facility (GSFs) is an indirect recharge facility that uses surface water (CAP water) instead of pumped groundwater. The Arizona Water Bank partners with an entity (farmer or irrigation district) that would have been pumping groundwater to grow a crop and provides CAP water in-lieu of the pumped groundwater. The Water Bank then gets a long-term storage credit for the groundwater not pumped.