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Testing Groundwater Recharge Strategies with Recycled Water 

What’s the purple hydrant and pipe about?

Post Date: 7/30/2021

Flagstaff Water Services is taking an exciting first step in evaluating ideal locations for aquifer recharge of our Class A+ reclaimed water, working toward a reliable water future.

Last year, seepage studies were conducted in three washes around town to measure infiltration rates for aquifer recharge, where a newly installed purple hydrant released 500 to 1,000 gallons per minute of reclaimed water. 

About 20% of the City’s annual reclaimed water resource is used by customers, with another 10% released into the Rio de Flag wash to satisfy an agreement the City has with the Arizona Game and Fish Department, supporting riparian habitat. This leaves 70% of reclaimed water available to earn aquifer recharge credits through the Arizona Department of Water Resources programs. Currently, the excess water is discharged to the Rio de Flag, complying with the state discharge permit for water quality, but not necessarily providing an intentional water resource benefit to the Flagstaff community.

Indirect aquifer recharge is one of several options under consideration in the Reclaimed Water Master Plan, which will guide the best and highest use of uncommitted reclaimed water.

The results of the seepage study are available on pages 16 and 17 of the Report to the Water Commission. Whether for a short term or long-term benefit, this project informs just one of many options that support a sustainable water management future for the Flagstaff community.

Questions or comments? Reply to ldeem@flagstaffaz.gov or call Lisa Deem, at (928) 213-2471

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