Environmentalists ask state to regulate groundwater pumping near the San Pedro

An environmental coalition is making the third effort in 35 years to secure state management of groundwater for the beloved but hotly contested San Pedro River.

Calling itself the San Pedro Alliance, the group asked the Arizona Department of Water Resources late Wednesday to create a state-run Active Management Area to oversee and protect groundwater resources in the Upper San Pedro River Basin.

“What we want it to accomplish is that the basin will be at safe yield. That is defined as no more groundwater is being withdrawn than is being replaced annually,” said Robin Silver, leader of the alliance and a founder of the Tucson-based Center for Biological Diversity.

The river basin has been in a deficit situation for decades, with more groundwater pumped every year than is replenished by rainfall, artificially recharged sewage effluent, storm water and other sources.

The size of the deficit has declined substantially since the 1990s. But many scientists, environmentalists and studies have continued to warn that the river could eventually dry up if the deficit isn’t eliminated.

If an Active Management Area is created for the San Pedro basin, it will be the seventh of its kind in the state. Five such areas, including one in the Tucson area, were created with passage of the pioneering Arizona Groundwater Management Act in 1980.

Last November, voters in the Douglas area approved a referendum to create a sixth management area, for the Douglas Basin. Voters in the Willcox area turned down creation of a water management scheme at that election for the Willcox Basin.

Likely opponents in Sierra Vista

The San Pedro Alliance petition will likely be opposed by many community leaders in the Sierra Vista area, including officials of the Upper San Pedro Partnership. That’s a nonprofit group representing 15 federal, state and local agencies, along with a realtors’ group, a major local developer, and other conservation groups not affiliated with the alliance’s effort. The partnership has sought to preserve the river without resorting to mandatory curbs on water use or limits on population growth.

Robert Glennon, a retired University of Arizona law professor who has extensively researched water issues and criticized what he sees as excessive water use across the state, is non-committal about an Active Management Area for the San Pedro Basin.

It is a “blank slate” today about what kinds of powers such an area will have, he said, adding, “It’s hard to say if an AMA is good or bad without knowing what this one will do.”

The Upper San Pedro Basin stretches from Arizona’s border with Mexico to an area of the river north of Benson known as the Narrows. It covers more than 1,700 square miles, making it larger than Rhode Island and more than 80% of the size of Delaware.

It includes the cities of Sierra Vista, Bisbee and Tombstone and covers the entire length of the 40-mile-long San Pedro Riparian National Conservation Area. That area was created by Congress in 1988 to protect the river from future degradation.

Lacking any dams or diversions, the San Pedro is the last remaining free-flowing desert river in the Southwest. The river has long had global recognition as prime habitat for birds, mammals and other wildlife.

Pressures on aquifer

But urban and rural growth along the river have put pressure on the area’s groundwater aquifer.

Conservation measures and major retirements of farmland in the area have shrunk the deficit from 15,000 acre-feet annually a generation ago, to about 5,100 acre-feet in 2015, to around 3,800 acre-feet as of 2020. But existing statistical margins of error in the deficit calculations are large enough to make the real difference between 5,100 acre-feet and 3,800 acre-feet meaningless, Silver said.

In 1988 and again in 2005, ADWR rejected efforts by the Sierra Club and the San Pedro Alliance, respectively, to get an Active Management Area declared for the Upper San Pedro Basin.

In 2005, then-ADWR Director Herb Guenther wrote that creation of an AMA for the basin wasn’t necessary “because there are sufficient groundwater supplies to meet the future needs of municipal, industrial and agricultural water users.”

Glennon observed, “If Robin thinks that this petition is going to get a different reception from (current ADWR Director) Tom Buschatzke and DWR, what is it in his presentation that will turn heads at DWR and make them want to create an AMA when twice before they refused?”

Silver said his response to that question is contained in the petition he submitted to ADWR.

In the petition, the San Pedro Alliance said ADWR’s 2005 decision ignored the federal government’s use of river water in the federally run San Pedro Riparian National Conservation Area. It includes a two-mile-wide area along the river, running from the Mexican border to just south of Benson.

The river has a “congressionally assigned right” to river water, the petition noted.

The petition also cited what it said was ADWR’s approval of the drilling of more than 1,800 new wells in the San Pedro Basin since 2005.

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It also cited the state’s finding that an adequate, 100-year water supply exists in the basin for the nearly 7,000-home Tribute development in Sierra Vista — a project that Silver himself tried unsuccessfully to stop in court.

It also mentioned the proposed 28,000-home Villages at Vigneto project in Benson, lying about 4 miles west of the river. That project’s approval under the Clean Water Act was suspended in 2021, but a U.S. Supreme Court decision this year is likely to free Vigneto from the act’s authority over development along the normally dry streams running through the project site.

The alliance also cited an acknowledgment by the Upper San Pedro Partnership in 2014 that it hadn’t met a commitment it made and that Congress had ordered in the 2000s to eliminate the basin’s groundwater deficit by 2011. That year, the deficit was about 5,100 acre-feet.

“The only way the river is going to survive is if there is a way to enforce what has already been promised by the locals,” Silver said. “The only way to enforce that is with an AMA. There’s no other mechanism to enforce it.”

City manager disputes need

In reply, Sierra Vista City Manager Chuck Potucek, who chairs the partnership’s administrative committee, said, “An AMA really does nothing to help improve conditions in the river. Based on everything we have done and we are doing, I think we are held to a higher standard here already than other places in the state.”

He posed the question of which of the existing Active Management Areas have met their goals of ending groundwater overdrafts by 2025, as set by the state groundwater law. A 2021 report from an Arizona State University water research group found none of them but the Tucson Active Management Area have come close to achieving “safe yield.”

That report, citing information provided by ADWR, noted the Tucson area has reached safe yield on and off in recent years, but said that achievement would clearly be threatened if major cuts to the Central Arizona Project canal system occur due to continually shrinking water supplies on the Colorado River from which CAP water comes.

“Our numbers are so much of a pittance compared with those places,” Potucek said of the San Pedro Basin’s groundwater deficit compared to those in the Phoenix, Tucson, Prescott and Pinal County AMAs. The U.S. Geological Survey’s estimate of a 3,800 acre-foot deficit in 2020 is an “old number.” he said. “I have a feeling it is less.”

Sierra Vista has done “a lot of work” on building codes to require Environmental Protection Agency-certified, water-saving plumbing fixtures in new homes. Plus, the city’s population now is growing less than 1% a year. “We don’t have growth that’s driving deficits here,” Potucek said.

Cochise County has since 2002 operated an effluent recharge project near the river in an area northeast of Sierra Vista, he said. Authorities have also created two projects to capture and recharge storm water for the river north and south of the effluent project, known as the Environmental Operations Park. More such projects are planned.

“The deficit — it’s a metric, a number we need to keep working on,” Potucek said. “The focus of a lot of our efforts continues to be on conservation, trying to get these projects going.”

Silver, however, noted that in a ruling last month establishing a numerical water right for the river’s conservation area, Maricopa County Superior Court Judge Mark Brain was skeptical that the existence of such projects would eliminate the need for federally guaranteed water rights.

New court ruling’s impact

Over the multi-year course of the case Brain decided, agencies and companies that opposed federal efforts to “quantify” the conservation area’s water rights said either that the recharge projects make that unnecessary, or that the feds should take these projects into account in their calculation of river water rights.

Brain, however, wrote, “Given that the relevant entities cannot guarantee that their efforts will continue in perpetuity, or that their recharge efforts will maintain the groundwater levels, the recharge efforts cannot serve as a substitute for a guaranteed water right.”

If that’s the case, the recharge projects also can’t serve as a substitute for state management of the river, Silver said.

The San Pedro Partnership’s chairman, Bisbee Mayor Ken Budge, said there’s not always a direct connection between the river’s groundwater deficit status and its long-term health.

“You can’t just assume because there’s more pumping than recharge, that means the river will run dry. There are many mitigation projects that have occurred and are occurring, and we’ve planned more, that will start (replenishing) the San Pedro,” said Budge.

It’s important to protect our water and keep the river viable, said Budge, who said he spoke for himself and not the entire partnership. “It’s such a great flyway and an important ecological part of Southern Arizona.”

But creating an Active Management Area won’t necessarily help the river survive, he said.

“The deficit figure does not necessarily directly connect with groundwater running into the river, versus what’s happening hundreds and hundreds of feet below the ground. It’s much more complicated than that,” he said.

Tricia Gerrodette, president of another conservation group, the San Pedro 100, countered, “There really is quite a direct connection. The wells that are near to former agricultural wells that pumped huge amounts of water have indeed started to rise in some cases. And other large wells have slowed their rate of decline but I’m not aware of many wells in the regional aquifer that are no longer declining.

“And maybe you can’t just assume because there’s recharge projects that the river will run wet,” said Gerrodette, who supports the AMA petition drive.