Newly designated Ranegras Plain Active Management Area becomes Arizona’s 8th groundwater basin designated for comprehensive protection of groundwater supplies

Arizona has designated the Ranegras Plain Groundwater Basin as the state’s eighth Active Management Area (AMA), a significant step toward managing groundwater depletion in one of the state’s most stressed aquifers. 

Arizona Department of Water Resources Director Tom Buschatzke issued his Findings, Decision and Order on January 9, confirming significant groundwater declines and associated land subsidence in the basin, and finding that the basin meets the statutory criteria for AMA designation. 

As a result of the designation, the Ranegras Plain AMA becomes Arizona’s eighth AMA, and the third AMA established since 2022. 

AMAs are the product of Arizona’s 1980 Groundwater Management Code. They are groundwater basins within the state that are subject to certain statutory and administrative regulations regarding the withdrawal and use of groundwater. In addition, Arizona has three Irrigation Non-expansion Areas, or INAs, which require large-volume water users to measure and record water use, and cap the expansion of agricultural acreage.

The future of residents and businesses depends upon protecting the finite groundwater resources in the Ranegras Plain basin. This is a critical step in achieving that outcome, said Director Buschatzke.

For decades, groundwater levels in the Ranegras Plain, spanning portions of La Paz and Yuma counties, have been falling. ADWR data show that annual withdrawals have outpaced natural recharge by roughly 900 percent. One well in the basin shows a water level decline of over 240 feet since the 1980s. 

The increase in groundwater extraction has triggered land subsidence in the region, threatening wells, private property, and infrastructure, as well as future water storage capacity, since subsidence is an indication of permanent compaction of the aquifer.

Governor Katie Hobbs, speaking during her annual State of the State address on Monday, January 12, emphasized the urgency of state intervention. 

We can no longer sit idly by while our rural communities go without help, Hobbs said, framing the designation as a necessary measure to protect both families and farms, as well as Arizona’s groundwater supplies.

The Department first identified the Ranegras Plain Groundwater Basin as a basin experiencing significant groundwater level declines at the Governor’s Water Policy Council Rural Groundwater Management Committee meeting held on August 17, 2023.

The new AMA designation will require most water users using high-capacity (or, non-exempt) wells in the Ranegras Plain AMA to begin measuring and reporting groundwater use. Additionally new irrigation acres are prohibited beyond those irrigated within five years of the November 5, 2025, baseline, except in cases where a substantial capital investment has been made to bring the land into irrigation. 

As it did in the wake of the creation of the Willcox and Douglas AMAs, ADWR will work with local stakeholders to develop a Management Goal and Plan that includes mandatory conservation requirements.

During the formal process preceding the Director’s designation, the Department received hundreds of comments on the proposed AMA designation.  The vast majority of those comments indicated support for the AMA as essential to preserving dwindling water resources and the local economy.

ADWR staff will continue outreach and planning in the coming weeks as the Department implements the AMA framework, with ongoing dialogue expected among farmers, residents, and stakeholders as the region adapts to the new designation.