THE DEVELOPMENT AND PROGRESS OF MANAGED AQUIFER RECHARGE IN ARIZONA: A GUIDE FOR OTHERS TO FOLLOW

The growth in the use and application of managed aquifer recharge (MAR) in Arizona is a good example of progressive development of this technology for the improvement of the management of the limited water resources of a semiarid region. It can be used as a guide for areas which are evaluating appropriate methodologies applicable to better the administration of their water supply. In Arizona this development was realized in four phases.

Phase 1: Experimental Studies. It consisted of academic and institutional research and small scale testing using both direct surface and well recharge. The best known work of this phase was the Flushing Meadows Project to study soil aquifer treatment. This phase lasted from the late 1960s to the early 1980s.

Phase2: Demonstration Projects. This phase was triggered by the urgency to store excess Colorado River (CAP) water at the completion to Phoenix of the Central Arizona Project aqueduct in the mid-1980s. The City of Phoenix Cave Creek and Agua Fria projects tested the feasibility to store in the regional alluvial aquifer the CAP water using either wells or basins, respectively. Aquifer storage of reclaimed water was also evaluated in several demonstration projects.

Phase 3: Development of Large Capacity Water-Spreading Facilities. The completion in 1994 of the Granite Reef Underground Storage Project started this phase and was followed by seven more MAR facilities with capacities exceeding 60 million cubic meters/year, the last one of these completed in 2009. Only two of these facilities store reclaimed water in addition of CAP water. The increase direct use of CAP water and the excess of storage capacity terminated this phase.

Phase 4: Operation of Small to Intermediate Capacity MAR Facilities. During the on-going phase only projects with capacities smaller than 25 million cubic meters/year are being developed. Most of these facilities only store reclaimed water and many use vadose zone recharge wells similar in design to those first used in Scottsdale’s Water Campus Facility. Other new MAR facilities are planned using fractured rock aquifers. The Town of Payson will use ASR wells to store 4 million cubic meters/year of reservoir water in the Proterozoic Payson Granite aquifer.