Center for Biological Diversity

The San Pedro River

San Pedro River
by Robin Silver


8-7-06: Sierra Vista To Fort Huachuca: “Get Lost!”

2-6-2006: ADEQ breaks law to benefit Sierra Vista developers

10-3-05: Local realtors/lenders warned to stop water supply ruse

3-17-05: Fort Huachuca violations of San Pedro compact challenged; Expansion exceeds mitigation, jeopardizes River

9-7-04: Consumer Complaint Filed against ADWR

6-8-04: Arizona Defends Its Right to Destroy the Last Free Flowing River in the Desert Southwest for Developers’ Benefit; Center for Biological Diversity Counters With Lawsuit

10-29-03: Rep. Grijalva proposes a win-win solution for the San Pedro River and Ft. Huachuca.

8-26-03: Groups appeal to Gov. Napolitano to help save San Pedro River

4-24-02: Dept. of Defense seeks exemptions from environmental laws

4-8-02: Judge rules Fort Huachuca endangering river, water conservation plan is inadequate

6-15-99: NAFTA Scientific Panel Declares San Pedro River is Seriously Overdrafted

6-15-1999: Ribbon of Life: An Agenda for Preserving Transboundary Migratory Bird Habitat on the Upper San Pedro River

Amphibians & Reptiles
Endangered Species






The San Pedro River Watershed, located along the Sonoran and Chihuahuan desert interface, and being influenced by both the Rocky Mountains and the Sierra Madre, is one of the most biologically diverse ecosystems on earth. It is also one of North America's most important wildlife havens. More than four hundred bird species--nearly half the U.S. total--live in or migrate through the basin. It is also home to 180 species of butterflies, 87 species of mammals, and 68 amphibians and reptiles. The San Pedro has the highest diversity of vertebrate species in the inland U.S. and the second highest diversity of land-mammals in the world.

In recognition of its biological importance, the American Bird Conservancy picked the San Pedro as its first "globally important bird area," The Nature Conservancy deemed it one of the eight "last great places" in the northern hemisphere, and in 1988, Congress recognized its value by establishing the nation's first Riparian National Conservation Area along a 45-mile stretch of the upper river.

If endangered species such as the jaguar, Mexican spotted owl, cactus ferruginous pygmy owl, southwestern willow flycatcher, loach minnow, spikedace, and Huachuca water umbel are to survive another century, it will be because humans had the foresight and political will to preserve this last great undammed river of the Southwest.

But the San Pedro River is drying up. Unsustainable water pumping has caused base flows to decline by 67% since the 1940s. The current population of more than 50,000 people in the upper basin is pumping more than 7,000 more acre feet (2.3 billion gallons) out of the aquifer each year than are recharged by rainwater. By 2020 the deficit will reach 13,000 acre feet (4.2 billion gallons) per year. Unless things change soon, the San Pedro will resemble the lower reaches of the Santa Cruz, Gila, Salt, and Colorado Rivers: dry, treeless, and devoid of the diversity of life which once graced its waters and shores.

The burgeoning water deficit is being caused by unsustainable population growth and lack of water conservation planning. Fort Huachuca, a U.S. Army base next to the town of Sierra Vista, is the largest single water user in the valley. The region's biggest employer, it is responsible for both large numbers of soldiers on base and large numbers of civilian contractors off base. Even so, it refuses to close down its federally funded golf course, or commit to concrete steps that will ensure the future of the river and the many species that depend on it.

Unplanned growth, combined with a lack of rational county and state water policies, is increasingly contributing to drying of the river as well. Though agribusiness has declined in both the U.S. and Mexican portions of the watershed, water inefficient crops also contribute to the problem.

The Center for Biological Diversity has worked to protect the San Pedro and its wildlife since filing our first Endangered Species Act petition to protect the Mexican spotted owl in 1989. The Center has also won Endangered Species Act protection for the cactus ferruginous pygmy owl, southwestern willow flycatcher, jaguar, Sonoran tiger salamander and Huachuca water umbel, and is seeking federal protection for the yellow-billed cuckoo, Gila chub, and Chiricahua leopard frog. The Center has also won the designation and protection of specific "critical habitat" areas along the river for the flycatcher, pygmy owl, loach minnow, and spikedace, and in the upper watershed for the spotted owl.

To reform water use in the basin and ensure the San Pedro remains a free-flowing river, the Center is pressuring Fort Huachuca to adequately mitigate its presence both on and off the base, is challenging the hydrologic basis of Arizona water law, and has joined with the San Pedro Alliance to ask the State of Arizona to designate the San Pedro River Basin an "Active Management Area". Aquifer pumping in Active Management Areas must be managed to ensure a one hundred year supply of water. Though the law applies statewide, the Sierra Vista urban area was excluded from AMA designation because of pressure by local development interests.

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