Groundwater - Groundwater is the current sole source of water for District customers. Metro Water has 26 active wells that pump water from the aquifer underneath the Cañada del Oro Wash and Rillito River. Water from the wells is placed in storage tanks or reservoirs. The water is then pressurized to move underground through pipes to reach the customers. The Metro-Hub service area has 5 wells that pump water beneath the ground along Sabino Canyon Creek and Tanque Verde Wash. The Metro-Southwest service area has 5 wells that pump water.
Water Usage - Metro-Main customers used 7,285 acre-feet (2.37 billion gallons) of water in 2013. While all the water was pumped from wells, almost of it was calculated as recovered CAP water based on the credits the District accrued through its recharge efforts as described below.
Metro Hub customers used 867 acre-feet (283 million gallons) of water in 2013.
Metro Southwest customers used 356 acre-feet (116 million gallons) of water in 2013.
Other Water Sources - Based on the Arizona Groundwater Management Code and Metro Main and Metro Southwest - Diablo Village's assured water supply designations, the District has sought to use a renewable water source to reduce its dependency upon groundwater in these service areas. The urgency to utilize renewable water has increased as groundwater levels have declined on average two feet a year for over a decade in Metro Main. In Metro Southwest, there is a need to stabilize groundwater levels.
Central Arizona Project Water - Metro Water District has an annual 13,460 acre-feet allocation of CAP water. Metro Water has primarily looked at replenishing CAP water by pursuing projects in which the water is recharged by spreading basins (direct recharge projects) and in which CAP water is used in lieu of groundwater by farms (groundwater savings projects). In fact, Metro Water District helped initiate the Northwest Replenishment Program, an effort to recharge CAP water in northwest metropolitan Tucson. The first project under that Program, the Avra Valley Recharge Project (1996), was the first recharge project using spreading basins in Pima County and was done in partnership with CAP and BKW Farms.
Since 1996, Metro Water District has stored 144,514 acre-feet of water credits through its CAP water recharge efforts. After using those credits, the District has in its "account", 18,913 acre feet of CAP credits.
Over the years, the District has pursued how to bring CAP water to the service area, which has involved joint studies with other northwest Tucson water providers and the US Bureau of Reclamation.
Avra Valley Recharge Project and Recharge CAP Allocation - In 2010, the District Board approved the use of recharge as the initial treatment method for its CAP water allocation. Recharge was seen as a less expensive alternative with lower capital but still as effective as a treatment plant. The District's CAP allocation would be recharged in the Avra Valley Recharge Project (AVRP), which the District had entered an agreement in 2009 with CAP to acquire. The acquisition was completed in January 2011.
CAP Recharge, Recovery & Delivery System - The CAP Recharge, Recovery & Delivery System (CAP RRDS) will recover CAP water through wells that has been recharged at the Avra Valley Recharge Project and then move the water through a 13 mile transmission line to be blended with groundwater at the Herb Johnson Reservoir. This approach is similar to Tucson Water's usage of their Central and Southern Avra Valley recharge facilities. The Project is estimated to cost $36.1 million.
In April 2014, the Board approved a 10-year timeline to accomplish the three major components for the Project - Land Acquisition, Design, and Construction. The timeline ensures that the Project can be accomplished efficiently but also with the least financial impact to customers.
The District is still working with the Town of Marana, Town of Oro Valley and Flowing Wells Irrigation District, which are also exploring recharging their CAP allocation at the Lower Santa Cruz Recharge Project. The District and Oro Valley may use the same delivery line.
Recycled Water - The District has access to approximately 2,686 acre-feet of effluent or recycled water generated from its service area. In May 2001, the District approved an agreement with the City of Tucson to transfer the effluent that has historically been under the City's control. The District has secured with the area's other water providers to obtain credits from the effluent through a joint managed recharge project. The effluent could someday be used to replace groundwater irrigation for large turf facilities in the District. This would require utilizing a reclaimed system and construction of a delivery system to move the effluent where it may be needed. The credits earned annually from the joint management recharge project in the Santa Cruz can be used to offset groundwater pumpage or purchase of a recharge facility.
The District is also planning to deliver a portion of its recycled water to Cortaro-Marana Irrigation District (CMID), a local agricultural irrigation district. This would allow the District to receive substantially more recycled water credits and reduce groundwater pumping in the region by CMID.
The District constructed a pipeline to deliver reclaimed water to the Omni Tucson National's new nine holes. Pima County granted Omni Tucson National until 2016 before it has to start taking that water. The use of reclaimed water will help to reduce the decline of groundwater.