TUCSON, Ariz.― Conservationists filed a petition late Wednesday with the Arizona Department of Water Resources that seeks to curtail rampant groundwater depletion in southeastern Arizona’s Upper San Pedro Basin.

“Rapacious groundwater pumping across the Upper San Pedro threatens the continued existence of life in this entire region,” said Robin Silver, a cofounder of the Center for Biological Diversity. “We’ve been asking the state to protect this biologically rich watershed for decades, but pumping continues unabated. The Hobbs administration must immediately use its power as promised to intervene on behalf of the people, plants and animals of southeastern Arizona.”

The petition, filed by the San Pedro Alliance, asks Arizona Department of Water Resources Director Tom Buschatzke to designate the Upper San Pedro Basin as the state’s seventh active management area. Arizona’s 1980 Groundwater Management Act grants the director the authority to designate active management areas “to preserve the existing supply of groundwater for future needs” and requires the department to certify a 100-year water supply for new development in those areas.

The Upper San Pedro Basin extends from the U.S.-Mexico border in southeastern Arizona to north of Benson. The U.S. Army’s Fort Huachuca is located in the basin and is the largest single source of groundwater pumping.

“Over the last two decades the Department of Water Resources has permitted thousands of new wells in the Upper San Pedro, despite numerous studies that show it’s in severe overdraft,” said Tricia Gerrodette, president of San Pedro 100. “Our ability to preserve the river for the future is being foreclosed. We need an active management area designation now.”

The San Pedro River is the last free-flowing desert river in the Southwest. Endangered species that depend on it include southwestern willow flycatchers, Huachuca water umbels, desert pupfish, loach minnows, spikedace, yellow-billed cuckoos, Arizona eryngo and northern Mexican garter snakes.

The department has 60 days to respond to the petition.