ADWR team steps up to provide analysis of groundwater supplies in every Arizona basin

December 8, 2023

The Arizona Legislature has asked ADWR to conduct periodic groundwater “supply and demand” assessments in order to improve our understanding of the current and future water conditions and to assist in future planning throughout the state.

Example of a depicted water budget, including the available supplies and demands and how they contribute to changes in groundwater in storage.

The law's timeline is specific. It requires that beginning this year, the Department shall conduct annual water supply-and-demand assessments for at least six of Arizona’s 51 groundwater basins. Further, a water supply-and-demand assessment is to be completed for all groundwater basins, including Arizona’s initial active management areas, at least once every five years.

For areas of the state outside the regulatory range of the Department, making assessments can be challenging. Outside of Active Management Areas, data is limited.

Nevertheless, ADWR analysts accepted the enormous challenge of producing the first round of Supply and Demand assessments – on time, at the end of a frenetic “sprint” to meet their assigned deadline.

Assessing supply and demand of groundwater in Arizona’s basins required developing analysis methods specifically tailored to the unique requirements of the project, which included focusing on “average well depth” – an approach that distinguishes these reports from the Department's typical hydrological assessments. Rather than using a standard depth across all basins for groundwater volume estimates, these assessments use a customized depth for each basin to better understand how much water is accessible using typical existing infrastructure.

This was an interdisciplinary exercise that required putting together a team from the Department’s Active Management Area and Statewide Planning sections, as well as collaboration with its hydrology, surface water, wells, adjudications, and legal divisions.

Together, that assembled team provided expertise in hydrology, data analysis, data visualization, stakeholder outreach and engagement, and reporting.

Diagram of a typical Basin and Range aquifer, not to scale. This diagram does not represent actual geology and is only for illustrative purposes. The dashed lines represent different depths used to calculate storage which can make a significant difference to the estimated volume of water. The blue shaded area represents the saturated volume calculated in the 2023 Supply and Demand Report.

All groundwater basins are distinct. The team’s game plan ensured the methods that were developed addressed the complexities and inherent dynamics of each basin. This included examining industrial, agricultural, and municipal uses and the multiple identified supplies in each basin. The team also developed projection scenarios to explore different outcomes for the basins based on changing parameters in the future.

In all, the team produced seven in-depth basin reports and a Methods Appendix detailing the analysis methods. This material underwent a rigorous and multi-faceted review process to ensure accuracy, reliability, and consistency with regulatory standards.

The team also created a user-friendly and interactive dashboard using PowerBI to offer a visually intuitive platform for stakeholders to explore and understand the findings of the assessments.

The team also designed a new landing page on the Department's website to host the reports and related materials.