By Rose Law Group Reporter
Casa Grande, AZ – After two years of studies analyzing the state’s 2019 Assured Water Supply Groundwater Model for Pinal Active Management Area (AMA) used by state regulators to determine if an
assured water supply exists using groundwater in Pinal County, a Pinal AMA Groundwater Task Force
chaired by Pinal County Supervisor Stephen Q. Miller, presented a summary of its own study to the Arizona Department of Water Resources (ADWR) on Tuesday March 29th. This new study demonstrates that all assured water supply and municipal demands over the next 100-years can in fact be met.
According to Supervisor Miller, “the original 2019 model reflects a regulatory approach which does not take into account the unique operations of water providers and this new submittal corrects that.” According to Terri Sue Rossi, Water Resources Manager for Arizona Water Company, the original 2019
model showed 8.1 million acre-feet of demands that could not be met using groundwater given assumptions in the regulatory model. “This volume represented only 10% of the total demands. This meant 90% of the demands in the model were in fact met. We let this be our guide.” Rossi who led the team of modeling experts explained that based on direction from ADWR, the modeling team set out to resolve unmet demands associated with assured water supply and municipal demands. “We needed to show that through a more robust operational strategy we could meet about 2 million acre-feet of assured water supply demands the original model showed could not be met.” According to Nathan Miller of Matrix New World, and the lead groundwater modeler, the team was able to meet those demands largely by accounting for water providers deepening and replacing existing wells and constructing new wells in locations more suitable for pumping groundwater consistent with how a water utility would most likely operate its water system over time.
Supervisor Miller and others acknowledge that while results are promising, growing our communities
entirely on groundwater is not sustainable. For example, the newly completed study continues to show depth-to-groundwater levels northwest of Eloy continuing to exceed assured water supply limits of 1,100 feet below the land surface. Jake Lenderking, Senior Vice-President of Global Water Resources described the latest study as an important step towards increased sustainability in the Pinal AMA and addressing ADWR concerns in the groundwater model. “This is a big step forward,” said Lenderking, “but more work needs to be done including figuring out how much groundwater use is sustainable and how we will collectively secure alternative supplies for the future. We look forward to working with ADWR and their staff to find the best solution.” For more information on this study, please contact Michael Cruz listed above.
