This notice commences the legal process that ADWR must follow to consider whether to designate the Willcox Groundwater Basin as a subsequent AMA. As a part of that legal process, ADWR is accepting comments and will hold a public hearing at 1:00 p.m. on November 22, 2024, at the Willcox Community Center. Information on the hearing, including webinar information, is available on ADWR’s website.  
Written comments not submitted at the hearing described above must be received no later than 5:00 P.M. on November 22, 2024, by mail or hand-delivery. Electronic or faxed submissions must be submitted prior to midnight on November 22, 2024. 
  
Sharon Scantlebury 
Docket Supervisor 
Arizona Department of Water Resources 
1110 W. Washington, Suite 310 
Phoenix, AZ 85007 
(602) 771-8686 (fax) 
[email protected] 
 
This notice also puts into place a temporary limitation on the expansion of irrigated acres: only acres that were irrigated between October 23, 2019, and October 23, 2024, may be irrigated going forward. This limitation remains in effect until ADWR makes a decision on whether to create an AMA. The limitation will remain in effect permanently if an AMA is established, but the limitation will be lifted if an AMA is not established. 

ADWR initiated a formal process to consider creating an AMA in the Willcox Groundwater Basin that includes opportunities for public participation:  

• Anyone interested may attend the public hearing at 1:00 p.m. on November 22 at the Willcox Community Center. Hearing details and webinar information can be found at on ADWR’s website (https://www.azwater.gov/find-info-on/how-do-i/willcox-groundwater-basin). 
• There is a public comment period in addition to this hearing, and anyone can submit comments at the hearing or in writing.  Written comments not submitted at the hearing described above must be received no later than 5:00 P.M. on November 22, 2024, by mail or hand-delivery. Electronic or faxed submissions must be submitted prior to midnight on November 22, 2024. 

  
Sharon Scantlebury 
Docket Supervisor 
Arizona Department of Water Resources 
1110 W. Washington, Suite 310 
Phoenix, AZ 85007 
(602) 771-8686 (fax) 
[email protected] 
 
Anyone who would like updates about the Willcox Groundwater Basin can request to be added to an Interested Parties Email List by sending an email to Dennis Troutman, AMA Outreach Coordinator, at [email protected].

 If an AMA is established in the Willcox groundwater basin:  

1. Anyone using water from a well with a maximum pump capacity of 35 gallons per minute (gpm) or less may not need a groundwater right. Please contact AMA Customer Service for more information at 602-771-8585 or [email protected]. 
2. Those using water from non-exempt wells (defined as greater than 35 gpm, OR irrigating 2 or more acres, OR using more than 10 AF for non-irrigation purposes) must submit an application for a grandfathered groundwater right within 15 months after the establishment of the AMA (A.R.S. § 45-476). NOTE: An applicant would be able to request consideration of substantial capital investment (SCI) that was made between October 23, 2019. and October 23, 2024, related to bringing land into irrigation (A.R.S. § 45-452(G)). These requests are considered on a case-by-case basis. 
3. After the application deadline, ADWR would publish a registry of all applications received, and anyone in the basin would have 180 days to file any written objections (A.R.S. § 45-479). 
4. ADWR would begin issuing grandfathered rights after the objection period ended.  

Dry wells can be reported through ADWR’s Dry Well Portal. If you are reporting a well that went dry in the past, it would be helpful to include information on when that well went dry. 

There are not currently plans to publish data from the Dry Wells Portal as a map, but information regarding dry wells observed by ADWR’s Field Services staff was presented at the September 26 Informational Meeting and can be found on slide 24.

Very generally, the main tools available to manage groundwater in an AMA are increasing recharge, reducing pumping through conservation, and encouraging the use of alternative supplies like effluent. More specifically, part of the establishment of an AMA is to lay out detailed strategies on how those general tools might be applied in a given basin, including developing a management goal and specific customized conservation programs created with local stakeholder input. Substantial customization is possible in that process; for this reason, ADWR will not speculate on what tools might be developed or utilized in a given basin. 

ADWR has not done specific modeling to simulate the impact of an INA or AMA. However, an INA allows existing irrigation to continue without limits on the volumes used and has no limits on other uses, so pumping could reasonably be expected to continue at current rates or increase. Under an AMA, specific conservation programs would be developed to reduce pumping over time, so groundwater decline could be expected to slow over time.  

ADWR does not have authority to exclude or stop specific existing users from pumping groundwater entirely.  Under the Groundwater Code, most existing water uses are grandfathered in and allowed to continue water use when a new AMA is created. These water uses are subject to mandatory conservation requirements designed to reduce withdrawals of groundwater, which are developed in collaboration with local stakeholders.  

Increasing recharge is one of the primary ways to reverse the water budget imbalance and improve the water level elevations across the basin. The potential impact of recharge would depend on the volume of water available to recharge and the recharge location.  

Unfortunately, it’s very difficult to predict when subsidence will cause an earth fissure to form. Earth fissures occur where there is land subsidence and subsurface bedrock ledges or ridges. The bedrock ledges or ridges within a subsidence feature cause deferential subsidence, which applies lateral stress to the formation material. The lateral stress creates hairline cracks in the soil that are later eroded into large subsurface voids.

The hydrologic data presented at the September 26 meeting included water level data collected by ADWR at specific well sites, as well as information about land subsidence and fissures, and analysis of that data to show trends in water level declines, subsidence, and fissuring. The 2023 Supply & Demand Report analyzes available information to estimate the water demands by sector and overall water supplies available within the basin.

ADWR cannot quantify or attribute general water level declines to specific water users but can make estimates of water use by sector. The 2023 Supply & Demand Report for the Willcox basin estimated the following sector water uses for the 2022 calendar year: 

• Agricultural: 155,805 AF 
• Industrial: 11,268 AF 
• Municipal: 910 AF

Groundwater overdraft occurs when more water is extracted from an aquifer than is recharged, resulting in declining water levels and loss of storage. The estimated overdraft in the Willcox Basin is 3.5 times more water going out than coming in, based on data from the USGS and the 2018 Willcox groundwater model. ADWR estimates 70,000 acre-feet per year of recharge in the basin (including incidental recharge from irrigated agriculture) and 247,000 acre-feet per year of outflow from the aquifer via pumping wells, native plant evapotranspiration, and underflow to adjacent basins.

In 2021, ADWR and the Arizona State Land Department (ASLD) published a report titled “Potential Water Storage Sites on Arizona State Trust Land” which identified multiple potential sites for recharge in the Willcox Basin. ADWR has not assessed the potential volumes or scale for recharge at these sites at this time.   

The report can be found here.