A court-ordered monitoring well tracking the health of the San Pedro River has run dry, according to new government data, and environmental groups say it’s further evidence that overpumping at the U.S Army’s Fort Huachuca is endangering the last intact river system in southern Arizona.
The Summers monitoring well was recorded as dry on June 30, according to data from the U.S. Geological Survey, meaning the water table had dropped below the depth of the well. Water in the well has been measured periodically since 1987, and this was the first time it came up dry.
The well is located near the San Pedro River, approximately seven miles north of Fort Huachuca. It is one of nine monitoring wells established by court rulings in 2023 and 2024 that quantified the amount of water entitled to the San Pedro Riparian National Conservation Area.
Congress created the San Pedro Riparian National Conservation Area in 1988, conserving almost 57,000 acres in southern Arizona to protect and enhance the rare desert ecosystem. The law also required that federal water rights be reserved for the conservation area.
Two other monitoring wells located near Fort Huachuca also showed declining groundwater levels falling below the court-ordered threshold.
‘San Pedro is being sucked dry’
During the driest times of the year, the San Pedro River relies on seeps and springs from underground aquifers to maintain its baseflow. When the the water levels in the aquifers fall, the river can dry up on the surface.
The national conservation area is managed by the Bureau of Land Management, and officials at the BLM did not respond to a request for comment on the declining wells.
“What more proof do our leaders need that the San Pedro is being sucked dry?” said Robin Silver, a co-founder of the Center for Biological Diversity, in a news release.
The center, an environmental advocacy organization based in Tucson, has tracked the health of the San Pedro River for years and has filed multiple lawsuits against the Arizona Department of Water Resources challenging the agency’s handling of the river and groundwater management.
The Arizona Department of Water Resources declined to comment on the well due to ongoing litigation.
The single largest user of groundwater in the area is Fort Huachuca, which has taken 400,000 acre feet of water since 1940, according to the center. Sierra Vista, located near the military base, also uses the aquifer as a primary water source.
Officials at Fort Huachuca did not immediately respond to requests for comment on this story.
“Years of inaction and relentless over-pumping in Fort Huachuca and Sierra Vista are pushing the river and the extraordinary plants and animals it sustains to the brink,” Silver said. “Arizona and the federal government must act urgently and decisively to save this ecological treasure from extinction.”
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In 2022, the San Pedro River was named one of the ten most endangered rivers in the United States by American Rivers, an environmental advocacy group, which cited excessive groundwater pumping as a major threat to the river’s survival.
The river is home to multiple endangered species protected by federal law, including the yellow-billed cuckoo, southwestern willow flycatcher, desert pupfish and Huachuca water umbel. The river also serves as a critical migration corridor for millions of songbirds every year.
John Leos covers environmental issues for The Arizona Republic and azcentral. Send tips or questions to john.leos@arizonarepublic.com.
Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust.
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This article originally appeared on Arizona Republic: A court-ordered monitoring well on Arizona’s San Pedro River runs dry