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Pinal Active Management Area Stakeholders Address Projected Water Deficit

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by L. William Staudenmaier

In November 2019, the Arizona Department of Water Resources (ADWR) released the results of an updated groundwater model that projects a groundwater availability deficit over the next 100 years in the Pinal Active Management Area (AMA) in central Arizona.  The 100-year projection is driven by Arizona’s Assured Water Supply program, which requires new residential and commercial subdivisions in AMAs to demonstrate a 100-year assured water supply before the land can be subdivided and new homes constructed.

The Pinal AMA is unique in Arizona because its statutorily mandated “management goal” seeks to balance the long-term water needs of irrigated agriculture with the future development of the non-agricultural economy.  See A.R.S. § 45-562(B).  Specifically, this statute states the goal as allowing “development of non-irrigation uses” while also “preserv[ing] existing agricultural economies in the active management area for as long as feasible, consistent with the necessity to preserve future water supplies for non-irrigation uses.”  The results of ADWR’s updated groundwater modeling projections are likely to make this statutory balancing act significantly more difficult in the years ahead because ADWR’s model projects 80 million acre-feet of water demand over the next 100 years, but only 72 million acre-feet of currently available water supplies in the AMA.[1]  This 10% deficit is equivalent to 80,000 acre-feet of unmet water demand each year.  While this may prove to be a manageable number, until and unless the gap is filled, further non-agricultural development in the AMA (on lands that do not already have a documented assured water supply) is likely to be stalled.

To address this problem, a group of Pinal AMA water stakeholders has been formed to identify potential solutions.  The stakeholder group, officially known as the Pinal Groundwater Task Force, is chaired by Pinal County Supervisor Stephen Miller.  To date, the Task Force has met on two occasions – December 9, 2019 and January 6, 2020.  However, as Supervisor Miller indicated at the first of these meetings, most of the detailed work of the Task Force is likely to occur in smaller working groups focused on specific water use sectors.  Separate groups are focused on agricultural water uses, current and future water needs for residential and commercial development within the AMA, municipal water providers, and water utilities that operate in the AMA.  These working groups have begun meeting and are expected to continue meeting on a regular basis over the next several months as they identify potential solutions to the water supply gap in the Pinal AMA.

At the first Task Force meeting, Supervisor Miller described the effort as both an opportunity for stakeholders to identify solutions and a responsibility imposed on those stakeholders to do so – because without solutions, future growth in the Pinal AMA will be stalled.  Supervisor Miller and other members of the Task Force indicated that there will not be any single, comprehensive solution.  Instead, the water supply gap will need to be addressed through multiple creative solutions that involve both more efficient management of existing supplies and identification of new renewable water supplies that can be imported to the Pinal AMA in an economically viable manner.  Other solutions may involve further refinement of ADWR’s updated groundwater model to incorporate more realistic assumptions regarding future water use in both the agricultural and residential/commercial development sectors of the Pinal AMA economy.

Consistent with this multi-pronged approach, the separate working groups were asked to identify “immediately actionable solutions” as well as medium-term and long-term solutions that may require additional discussion over the coming months and years.  As the working groups develop potential solutions in each category, they will report back to the full Task Force where the solutions will be discussed by all stakeholders with the objective of identifying a final list for implementation.

This work is critically important to all stakeholders in the Pinal AMA.  In the words of Supervisor Miller, “the future of Pinal County is at stake.”  Given this level of significance, stakeholders can expect to participate in numerous meetings over the next several months in an attempt to identify, vet, and implement a package of solutions that will allow future economic development in the Pinal AMA in a way that continues to honor the statutory mandate to balance the agricultural economy with future expansion of the non-agricultural economy.

[1] ADWR’s report documenting its updated groundwater modeling projections, as well as a power point presentation and other documents describing the model update process, are available on ADWR’s website at: