Wells show San Pedro water levels too low to meet court order

The imperiled San Pedro River is now below court-ordered minimum levels in four of nine monitoring wells used to track the health of the river’s national conservation area, federal records show.

A judge set those levels about a year ago when he issued an order specifying and quantifying the amount of federal reserved water rights in the San Pedro National Riparian Conservation Area. The area spans nearly 57,000 acres, stretches about 40 miles and runs from the Mexican border to St. David south of Benson.

The only way to get the well levels back to meeting the court requirements is to reduce groundwater pumping near the river, said environmental activist Robin Silver.

“Our leaders are leaving the San Pedro River unprotected and future homeowners vulnerable to their taps running dry, while these well levels continue to drop,” said Silver. “There’s still time to save this vibrant ecosystem, but people have to stop pretending there’s an endless supply of water. This new information shows it’s slipping away.”

U.S. Geological Survey records from June 2024 show:

• Three wells have fallen below the court-ordered minimums just since the August 2023 order from Michael Brain, a Maricopa County Superior Court judge.
• A fourth is also below the limit, although it rose three feet from the most recent well report prior to that, from January 2024.
• A fifth monitoring well is less than one foot above the federal limit and its water level stands at six to seven feet below the most recent well measurements before that, from 2011.

Those four wells’ water levels range from less than a foot to about 3 feet below the limits Brain set. Three of the four wells’ levels are also at least 3 feet below where they stood in the early 2010s.

Water levels in two other monitoring wells are significantly above the federal limits and no information is available on the other two wells.

The U.S. Bureau of Land Management, which owns and manages the conservation area, did not immediately respond to a request Tuesday to comment on the well levels.

Brain’s ruling followed a protracted legal dispute between the BLM and other water users including a mining company and the city of Sierra Vista.

Silver, who announced the well levels in a news release Tuesday, said the most logical way to reduce groundwater pumping near the San Pedro in a reasonable time period is to “downsize” Fort Huachuca, the area’s single biggest water user.

A co-founder of the Tucson-based Center for Biological Diversity, Silver has won several court cases over the past two decades overturning various federal biological opinions that allowed the fort to keep operating at its then-current levels despite the presence of several endangered species living near the river. The most recent of those rulings came in December 2023.

The U.S. Fish and Wildlife Service has revised the biological opinion after each of the earlier rulings. It was ordered by federal courts to “reinitiate consultation” with the fort over the river issue in the latest ruling, which typically means to revise the biological opinion once again. Silver has said he intends to keep suing to overturn these opinions in an effort to reduce the job count at the fort, one of Southeast Arizona’s largest employers.

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A major center for military intelligence, cybersecurity and drone training, Fort Huachuca is a joint-services installation training over 9,000 students a year, hosting about 5,600 military, 8,000 civilians and over 11,000 family members.

The fort is home to the U.S. Army Intelligence Center, the Army Network Enterprise Technology Command, the Electronic Proving Ground, the 2-13th Aviation Regiment, the Joint Interoperability Test Command and Libby Army Airfield, which shares its runway with Sierra Vista Municipal Airport.

The new well data, Silver said, “show how extremely dire the situation is for the San Pedro River ...,” Silver said. “Inaction in every direction is sucking the San Pedro dry and endangering the animals and plants that depend on this treasured river to survive.”

Silver has also sued the Arizona Department of Water Resources and Gov. Katie Hobbs to try to force them to start work on possibly designating the Upper San Pedro Basin as an Active Management Area.

He’s also sued the ADWR and Hobbs to try to force them to review and possibly revoke a decision ADWR made many years ago finding that a nearly 7,000-home development planned in Sierra Vista had an adequate 100-year water supply. That finding was necessary to allow the project to be built although it hasn’t started construction yet.

ADWR and the Governor’s Office have said in court filings that the first lawsuit is without merit and they have asked the court to dismiss it. They haven’t yet responded to the second lawsuit.

Asked about the latest well level reports on Tuesday, ADWR spokesman Doug MacEachern said, “As a matter of policy, ADWR does not comment on issues related to pending litigation.”

The river in general has suffered reduced flows over the past several decades that many past studies have blamed on over-pumping of the aquifer. Local, state and federal officials have been able to cut into the river basin’s groundwater deficit in the past decade or so but it remains about 3,000 acre-feet a year in the most recent estimate.

A 2021 ADWR report on the river concluded water levels in the Upper San Pedro Basin had declined an average of 3.9 feet between water years 2007 and 2019. A water year typically covers the period from October of one year through September of the following year.

Overall, ADWR found “considerable decline” in well readings, after evaluating water level changes in 320 wells across the basin, the department said in an article posted on its website in 2021.

The declining water levels show that historic cumulative groundwater pumping of approximately 2 million acre-feet since 1940 is overtaking efforts to mitigate excessive water use, Silver said.

Fort Huachuca, the single largest user of San Pedro River water, has taken 400,000 acre-feet since 1940, he said. Silver was citing a 2010 report on water use in the basin prepared by a Fort Huachuca consultant. It was discussing water use starting in 1902, and projecting future water use from 2010 through 2105.