This page features aerial photos of the Granite Reef Underground Storage Project (GRUSP), near Mesa, Arizona.
Roughly four miles downstream from the Granite Reef Diversion Dam, the GRUSP is a water-banking facility designed for storing water for future use in Phoenix. The project is funded and owned by the Salt River Project and six municipalities in Arizona, including Phoenix and Scottsdale. The project banks between 40,000 and 50,000 acre-feet per year when fully operational.
Here’s how the artificial groundwater storage works: First, Colorado River water flows through the Central Arizona Project canal and into the Salt River Project canal, where it deposits into the GRUSP Delivery Channel. Then, at the facility, the water is measured and distributed into recharge basins, which are the large and porous storage spaces made of sand and gravel. Here, the water seeps into the ground, contributing to the water already stored in the existing aquifer below.
The storage project was offline for around a year after the GRUSP delivery channel was washed out by flooding in 2020. The delivery channel was reconstructed in early 2021 and resumed artificial recharge in May 2021.
Learn more:
- Arizona’s Family, “SRP storing water underground to help with the drought” May 25, 2021.
- SRP: Newsroom, “SRP’s granite reef underground storage project (GRUSP) back online to assist with drought,” May 19, 2021.
- Casey Kuhn, “Water savings and checking accounts: How cities bank on future supply,” KJZZ, June 7, 2018.
| Date | January 10, 2019 |
| Location | Salt River, near Mesa, Arizona (map) |
| Credit | Ted Wood/The Water Desk |
| Rights | Free to reuse under Creative Commons license. |
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