The Altar Valley west of Tucson is one of the few unfragmented desert grasslands left in Arizona. It stretches more than 600,000 acres, from the Sierrita Mountains to the Baboquivari Mountains, and comprises working ranches and the Buenos Aires National Wildlife Refuge.

The valley is home to threatened and endangered species; jaguar Macho B prowled its mountains from 1996 until his death in 2009. In other words, the Altar Valley is what saving the wide-open spaces of the West is all about.

Kinder Morgan, the nation's largest pipeline provider, wants to construct a 59-mile pipeline down the Altar Valley to export natural gas to Mexico. The pipeline will cross the border at Sasabe, though existing pipelines cross at Naco, Nogales and Yuma, and a federally designated energy corridor runs through the Santa Cruz Valley. Kinder Morgan won't say why Sasabe, whose main industry is smuggling, is its crossing point.

The company has identified two routes down the Altar Valley. One would follow Arizona 286, a sparsely traveled two-lane blacktop. Because Kinder Morgan would require an additional 100-foot utility corridor through the refuge, the U.S. Fish and Wildlife Service opposes that "eastern route." The "western route" would veer away from Arizona 286, carving a new road and utility corridor across pristine desert grassland, which refuge biologists acknowledge would be even more environmentally destructive.

Local Border Patrol agents oppose both routes. According to agent Roger San Martin, "The installation of a pipeline would inadvertently create a route of egress for transnational criminal organizations. ... The rise in illegal traffic would subsequently result in a more robust smuggling infrastructure and a higher crime rate to border communities on both sides of the international border."

Pima County opposes the pipeline because the Altar Valley is critical to its Sonoran Desert Conservation Plan. The county invested $44 million in the valley by purchasing ranches that otherwise would have gone to speculative real estate. It owns more than 20,000 acres in fee title and holds an additional 62,000 acres of State Trust and Bureau of Land Management grazing leases in the watershed.

The Altar Valley Conservation Alliance, a 501(c)(3) grass-roots organization founded by local ranchers in 1995, works to promote conservation and sustainable stock-raising.

In January 2012, the alliance restored eight washes along a road near the proposed "western route." Even with an estimated 74 days of volunteer time, the work cost about $160,000, or roughly $20,000 per wash. Multiply that by the approximately 200 washes Kinder Morgan proposes to cross, and you have a very conservative estimate of $4 million to keep the pipeline from becoming an enormous erosive feature.

Ranchers in the alliance also know that new utility corridors mean more smugglers with AK-47s cutting fences and puncturing waterlines - and more horrific deaths from heatstroke or exposure as coyotes abandon migrants who slow them down.

A pipeline through the Altar Valley is ill-conceived and will degrade both border security and one of the last unfragmented valleys in Southern Arizona. It will lead to environmental damage in Mexico as well, carving a new utility corridor through fragile country. It will also threaten the Upper Gulf of California and Colorado River Delta Biosphere Reserve, which was recently named a UNESCO World Heritage site.

Please join the Altar Valley Conservation Alliance, Pima County, Sky Island Alliance and the Buenos Aires National Wildlife Refuge in opposing the location of Kinder Morgan's pipeline through the Altar Valley.

We should not sacrifice the safety of our citizens or the integrity of our desert grasslands to fuel speculative schemes in Mexico.

Thomas E. Sheridan, a research anthropologist and professor of anthropology at the University of Arizona, is a community representative for the Altar Valley Conservation Alliance.