In 2001, ADWR undertook a review of the Upper San Pedro Basin to determine if it met the statutory requirements for designation as an AMA. This report reviews the water supply and demand of the USP Basin in the context of the statutory criteria and includes a discussion of whether any of the criteria have been met. Previously, ADWR conducted a study of the USP Basin and issued a report in 1988 in which ADWR determined that the Basin did not meet the statutory criteria for AMA designation. ADWR indicated in the report that it would reassess conditions in the Basin in ten to fifteen years. The study described in this report is an evaluation of whether the conditions of the USP Basin satisfy the statutory criteria. This report contains a description of the current and projected water resources and water demand in the Basin, incorporating new information since the previous review. The report examines historic water use trends, evaluates the groundwater resources of the Basin, and projects impacts of future water use on Basin groundwater supplies. The report includes an evaluation of the incidence of subsidence or fissuring, and of the potential for groundwater quality degradation due to groundwater use. The report further describes and evaluates the impact that AMA practices would have on water use, and includes a summary of findings, the director’s determination of whether the Basin should be designated and recommendations.

The Hydrology Division of the Arizona Department of Water Resources has been in the process over the last two years of updating the geology used in the Department’s Salt River Valley Regional Groundwater Flow Model. The geology update is the first phase of an overall plan to update the model’s geologic structure, numerical grid and extend the model’s steady-state and transient calibration periods. Releasing the provisional geologic report at this time allows us to provide the new data and analysis to water providers and other model users prior to the completion of the overall model update. Please be advised that the geologic data and interpretations that are included in this report and accompanying database are provisional at this time and subject to revision.

The Arizona Department of Water Resources manages the state’s water supply. Water management includes a wide variety of activities that are intended to protect and preserve the water supply. Examples of these activities include licensing well drillers, assuring the safety of dams, and developing mandatory conservation requirements for all water use sectors in Active Management Areas, protecting the state’s Colorado River allocation and facilitating Indian water rights negotiations among tribal representatives, local interests, federal and state officials and members of Congress.