Groundwater Recharge and Replenishment

Water resources in Pima County support the natural environment as well as the urban community. The District’s statutory authority under ARS 48-3603 allows us to construct and operate groundwater recharge facilities that also have flood control benefits. Through the Groundwater Recharge and Replenishment program, the District uses this authority to replenish area aquifers. The Regional Flood Control District is involved in several pilot recharge projects, primarily intended to evaluate groundwater quality and riparian habitat viability.

The Marana High Plains Effluent Recharge Project was conceived as a two-year constructed pilot project to investigate the feasibility of using treated Santa Cruz River effluent to enhance riparian habitat while recharging the aquifer. Because of favorable recharge rates, the project was extended beyond the pilot stage, as noted in the fact sheet.

The Lower Santa Cruz Replenishment Project was completed in 1998 by the District in partnership with the Central Arizona Water Conservation District. The project was constructed in conjunction with a flood control levee along the Santa Cruz River to protect the Town of Marana from flooding and to provide for underground storage of Central Arizona Project water. Entities storing water include the Arizona Water Banking Authority, Central Arizona Groundwater Replenishment District, Metropolitan Domestic Water Improvement District, the Town of Marana and Robson Communities.

The Lower Santa Cruz Managed Recharge Project is a cooperative effort among the US Bureau of Reclamation, Pima County, the City of Tucson, Metropolitan Domestic Water Improvement District and the Town of Oro Valley to store effluent underground for recovery at a later time. Each of the cooperators have control of a share of effluent generated at Pima County’s Ina Road Water Pollution Control Facility and Roger Road Wastewater Treatment Plant that is discharged to the Santa Cruz River.

Located at the Avra Valley Wastewater Treatment Facility, the Avra Riparian Restoration and Groundwater Replenishment Project is a proposed project that will create a world-class site for wildlife watching; protection and enhancement of scarce riparian areas and wildlife habitat; environmental education and other outdoor recreations activities, while reclaiming, reusing and recharging valuable and scarce water resources.