Flowing north from Mexico into the Gila River in southeast Arizona, the San Pedro is one of the Earth's the most biologically diverse and important ecosystems. It supports 400 species of birds (nearly half of the U.S. total), 100 species of butterflies, 83 species of mammals and 47 species of amphibians and reptiles. It has the second highest diversity of land-mammals in the world. It was designated the first "globally important bird area" by the American Bird Conservancy and one of the northern hemisphere's eight "last great places" by The Nature Conservancy. In 1988 Congress recognized the unparalleled value of the San Pedro, designating 45 miles of it as the nation's first Riparian National Conservation Area.
Nevertheless, the river is drying up due to unsustainable sprawl and agribusiness. Baseflows have declined 67% since the 1940s and will eventually disappear if aggressive water conservation actions are not taken soon. The continuous expansion of Fort Huachuca is the single biggest contributor to the deadly overdraft of the river.
A lawsuit forced Fort Huachuca to submit its 10 year operation plans to the U.S. Fish & Wildlife Service for review under the Endangered Species Act. The Fish & Wildlife Service issued a draft decision that the Fort's operations would jeopardize the flycatcher and umbel. It laid out concrete actions the military would have to take to save the river. Under heavy political pressure, however, the agency later reversed itself, declaring that the military's water conservation plan was adequate. This decision was challenged in court. Noting that the Service's own biologists complained that the conservation plan "doesn't even come close" to offsetting the military's water withdrawals, judge Alfredo Marquez ruled that the agency "sidestepped its obligation to make an accurate "no jeopardy" decision based on the best available evidence."
Fort Huachuca will now have to develop a new, stronger water conservation plan and re-submit it for review to the U.S. Fish & Wildlife Service.