TUCSON, Ariz.— The Center for Biological Diversity released a new report today that links groundwater pumping at Fort Huachuca to reduced flows on the San Pedro River in southeastern Arizona.

The continuing downward hydrographic trend of Fort Huachuca’s monitoring wells shows that groundwater use is outpacing aquifer recharge, threatening people, plants and animals who rely on the aquifer and the San Pedro River adjacent to the fort.

“This data definitively proves that Fort Huachuca’s voracious groundwater pumping is an existential threat to the San Pedro River and all the creatures it sustains,” said Robin Silver, a cofounder of the Center. “The U.S. Army has spent decades denying that it’s doing anything to harm the river. That has to change today. With this data, the Army can no longer bury its head in the sand about its dominant role in killing the river.”

On May 16, 2005, a U.S. Army Corps of Engineers report about dropping levels on Fort Huachuca’s groundwater monitoring wells concluded: “it is likely this decline in water levels currently extends to the river, resulting in a reduction of groundwater discharge to the river when compared to predevelopment conditions.”

The Center applied the same methodology used in that 2005 report to link the steady drop in water levels at the fort’s own monitoring wells to the decline in the river’s flow. The water table under Fort Huachuca has dropped so sharply that underground water is now flowing backwards between two of the base’s monitoring wells, instead of following the historical flow towards the river.

Fort Huachuca is the single largest local user of the San Pedro River. Since 1950 the fort has used 400,000 acre-feet of water — enough to fill nearly 52,000 Olympic-sized swimming pools — which has not been replenished by recharge back into the aquifer.

The base’s population and related groundwater pumping were rapidly growing even before Trump announced he would be sending more troops to Fort Huachuca.

The San Pedro River is the last free-flowing desert river in the Southwest. Millions of neo-tropical songbirds rely on the river to complete their yearly migrations.

Endangered species who depend on the San Pedro include the southwestern willow flycatcher, Huachuca water umbel, desert pupfish, loach minnow, spikedace, yellow-billed cuckoo, Arizona eryngo and northern Mexican garter snake.