M&A’s long-term technical support results in permitting and successful operation of the largest recharge and recovery facility in Arizona.
Client: Central Arizona Water Conservation District (CAWCD) - Time frame: 2000–2009
- Location: Lower Hassayampa Basin, Western Arizona
CAWCD manages the CAP, which conveys water from the Colorado River to users in central and southern Arizona. Because Arizona’s allotment of CAP water historically exceeded customer demand, CAWCD hired M&A to investigate the feasibility of storing surplus water underground, where it would be available for future recovery during times of shortage. Beginning in 2000, we investigated six groundwater basins in western Arizona to determine the suitability for artificially recharging 200,000 to 300,000 AFY.
Our work resulted in the successful permitting of the Tonopah Desert Recharge Project located in the Lower Hassayampa Basin, about 50 miles west of Phoenix. The underground storage facility (USF) permit obtained from ADWR allows CAWCD to recharge up to 2 million AF over 20 years. Recharge operations began in January 2006, and more than 330,000 AF were successfully stored during the first 3 years of operations.
This facility now has the largest underground storage capacity in Arizona. Planning for recovery operations is in progress.
At the onset of the project, M&A characterized the hydrogeology of six groundwater basins in western Arizona, examining their structural and stratigraphic features, groundwater occurrence, and groundwater chemistry. To evaluate conditions in the vadose and saturated zones, we conducted exploratory drilling, trenching, geophysical investigations, and infiltration tests. We also developed a groundwater flow and transport model to predict the effects of full-scale recharge operations on groundwater levels and water quality.
Using information from the characterization efforts, we ranked the suitability of six sites for recharge operations, ultimately selecting the Tonopah Desert site as the most favorable for large-scale recharge.
M&A prepared the application for a USF permit, developing hydrogeologic reports, modeling results, and monitoring and contingency plans. To facilitate monitoring, we installed dual-completion piezometers in the vadose zone. We also conducted pumping tests and collected water samples at monitoring wells that were installed for this project.
M&A is involved in planning the recovery effort to enable CAWCD to retrieve the stored underground water supplies when there are shortages on the Colorado River. We designed a recovery well field that optimized production capability while minimizing the costs associated with well construction and ongoing operation and maintenance.
To help CAWCD manage ongoing recharge and future recovery operations at this remote facility, M&A’s HydroGeoMetrics Team designed an automated data-acquisition and telemetry system to continuously monitor groundwater levels in wells and piezometers.
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