The San Pedro Riparian National Conservation Area protects one of the river’s few stretches that stay wet year-round and is part of a critical corridor for desert wildlife. Ash Ponders

From Audubon Magazine

New Perils Threaten to Destroy an Embattled Desert Haven for Birds

Advocates have long fended off proposals that would deplete Arizona's San Pedro River, but today's threats add up to a daunting challenge.

Late one summer evening, just as the day’s monsoon rains receded, a 68-year-old activist named Robin Silver climbed through a barbed-wire fence outside Tombstone, Arizona. He was headed for a riverbend near the site of a ghost town locals know as Charleston. It had taken Silver most of the afternoon to cover the short distance from the nearest road, his path obstructed by pools and clots of dislodged cottonwoods—evidence of the season’s capricious flash floods.

At the bend, Silver stopped and peered up- and downstream. Beyond him in both directions ran the San Pedro River, its banks a ribbon of greenery unfurling gently through the red desert. “This is where the Charleston Dam site was,” Silver said. “Where it would have gone across.” Commissioned in the late 1960s as part of the U.S. Bureau of Reclamation’s vast network of reservoirs and canals, the proposal was scuttled in 1977 over concerns about its cost and impact on the river. A relatively minor move in the bureau’s remaking of the American map, Silver explained, it nevertheless granted the San Pedro a rare fate: Today it remains one of the last major free-flowing rivers in the Southwest.

Silver unshouldered his pack. “We come into places like this and dam the river, farm the fields, kill everything,” he said. A group of Turkey Vultures erupted from the canopy. “But this place still has a shot.”

Silver is a co-founder of the Center for Biological Diversity, a national organization that advocates for endangered species. In the decades since the Charleston Dam was defeated, CBD, local Audubon chapters, and other advocates have waged a near-constant battle to save the San Pedro and its riparian habitat, which serves as a breeding ground or migratory stopover for hundreds of bird species. They have won multiple lawsuits, arguing that the San Pedro is a vital but increasingly fragile island of biodiversity. “You hear us use the word last a lot,” Silver said of the San Pedro. “We’ve dammed and diverted the Rio Grande, the Gila, the Agua Fria, the Santa Cruz, the Colorado. They’re gone.”

With their complementary advocacy styles—she’s quietly consistent, he’s hard-charging and pugnacious—Tricia Gerrodette (top) and Robin Silver are among the San Pedro’s most dedicated defenders. Photos: Ash Ponders

In recent years the conflict over the river has shifted upstream, to the Army’s Fort Huachuca and the military community built around it, Sierra Vista. As the small city’s population has exploded, nearly doubling to more than 40,000 since 1980, so has its water consumption, damaging the aquifer that supports the river and drying up wetlands and tributaries. Since 2016 Silver and allies have been embroiled in a legal fight on two fronts: a suit alleging that the fort concealed its unsustainable water use for years, and an effort to block a massive housing development whose financier has ties to the Trump administration. But while the cases are similar to others they’ve won, river advocates have new reason to worry. The administration’s sweeping changes to the Endangered Species Act and Clean Water Act—historically two of the most effective tools for protecting the San Pedro—appear to have weakened the river’s defenses, even as it strains under a climate granting up to 40 percent less rain than decades ago.

A lifelong Arizonan, Silver was beginning to contend with the reality that the river might be on the verge of collapse. This was one reason he’d wanted to visit the dam site; seeing the undeveloped bend helped remind him of what had been overcome and what could still be lost. Standing in the river, he brought up the cautionary tale of the nearby Santa Cruz. Once a vibrant mosaic of trout holes and willow brakes, the Santa Cruz is now mainly a desiccated stretch of sand—its waters drained as the city of Tucson grew around it. “We stopped the Charleston,” Silver told me. “But these things never really die.”
 

K

nown through history as “Beaver River” and the “Valley of the Shadow of Death” for its confusing array of pools and biting insects, the San Pedro has long served as a rare shaded route through the scorching and disorienting Chihuahuan and Sonoran deserts. Ranchers still sometimes happen upon spear tips in the river from the last ice age, when Clovis people hunted mammoths along its banks.

From its headwaters in Mexico’s Sierra Madre Occidental to its confluence with the Gila River, the San Pedro runs dry in stretches and for parts of the year. It erupts in mid-summer, when deluges of monsoon rain scour the high mountains, gushing through its tributaries. The floods, like the desert, are volatile, and every year yields a different river. In a Nature Conservancy survey this past June, only 46 of the river’s 174 miles were wet. The river does not cease running, however; it merely drops a few feet from view. Below ground it flows on, seeping through sands and gravel, the riot of vegetation along its banks evidence of the hidden waters.

 

San Pedro

River Watershed

River

Major road

San Pedro Riparian

National Conservation

Area (SPRNCA)

ARIZONA

San Pedro River

watershed

SONORA

The planned 28,000-home Villages at Vigento would destroy tributaries and use about 2 billion gallons of water per year.

The San Pedro Riparian National Conservation Area was the first Globally Important Bird Area in the country.

Benson

Growing communities capture groundwater from rain and snow in the Whetstone and Huachuca Mountains, a vital water source for the San Pedro.

Whetstone

Mtns.

Charleston

Sierra

Vista

Pumping by Fort Huachuca, one of the area’s biggest water users, began harming the river as early as 2003, per a leaked report.

Huachuca

Mtns.

ARIZONA

SONORA

U.S.-Mexico border

A new border wall segment across the San Pedro will cut off wildlife and could act as a dam for monsoon floods.

20 Miles

0

10

Map: Lucy Reading-Ikkanda

 

San Pedro

River Watershed

River

Major road

San Pedro Riparian

National Conservation

Area (SPRNCA)

ARIZONA

San Pedro River

watershed

SONORA

The planned 28,000-home Villages at Vigento would destroy tributaries and use about 2 billion gallons of water per year.

Benson

The San Pedro Riparian National Conservation Area was the first Globally Important Bird Area in the country.

Whetstone

Mtns.

Growing communities capture groundwater from rain and snow in the Whetstone and Huachuca Mountains, a vital water source for the San Pedro.

Charleston

Sierra

Vista

Pumping by Fort Huachuca, one of the area’s biggest water users, began harming the river as early as 2003, per a leaked report.

Huachuca

Mtns.

ARIZONA

SONORA

U.S.-Mexico border

A new border wall segment across the San Pedro will cut off wildlife and could act as a dam for monsoon floods.

20 Miles

0

10

Map: Lucy Reading-Ikkanda

Although naturally occurring, these buried stretches are expanding and drying out as Sierra Vista and surrounding communities grow. Situated between the river and mountains, the city sucks up the groundwater that would otherwise seep into the San Pedro from below. According to a 2014 report to Congress, the Sierra Vista area is depleting its aquifer at the rate of about 1.6 billion gallons each year. With more wells capturing more water, stream flows have become increasingly dependent on rain, even as the Southwest suffers one of the harshest megadroughts of the past 1,200 years—and the first fueled by human-driven climate change. Some scientists are convinced that, absent a radical intervention, the San Pedro will run dry by century’s end. “This river is already teetering on the edge for natural reasons,” says Mark Murphy, a senior water scientist with the engineering company NV5 who has provided expert analysis to the legal team for San Pedro advocates. “It can be pushed over it so easily.”

One of the few stretches that remain wet year-round lies just east of Sierra Vista, in the San Pedro Riparian National Conservation Area. Around 350 bird species have been recorded at SPRNCA, among them Vermilion Flycatchers, Gray Hawks, and Tropical Kingbirds. Its nearly 57,000 acres are also home to more than 80 mammal species, and some of the few recent jaguar sightings in the United States happened nearby. 

Early one morning in August, I met up there with an activist and friend of Silver’s. Tricia Gerrodette is a slight woman of 70 with a graying squall of hair and oval glasses. We talked in the shade near the San Pedro House, a nearly century-old restored ranch that serves as a nexus of SPRNCA’s trail system. The air was heavy from overnight rain. As hikers stopped to wipe mud from their clothes, Gerrodette asked about their sightings, her face lifting with inquisitive warmth at the mention of each bird—seen or hoped for.

Gerrodette isn’t on staff at CBD or any other organization, but fellow advocates say she is critical to their ongoing fights. “She knows the river, knows the policies, and monitors so many different agencies,” says Sandy Bahr, Arizona chapter director at the Sierra Club. While Silver has been successful with a more hard-charging style of activism, Gerrodette’s quiet consistency in the lonelier, unglamorous tasks, such as filing public-records requests, has helped activists stay ahead of encroaching developments.

When Gerrodette and Silver began researching ways to protect the San Pedro in the 1990s, they found that state water law left them few options. Like many states, Arizona observes little legal connection between groundwater and an adjacent river; water users are free to keep pumping even if it drains a stream. This regulatory vacuum has forced advocates to think creatively, shifting their focus toward protecting the river’s dependents, often via the Endangered Species Act. The strategy has worked. Beginning with the Southwestern Willow Flycatcher, in 1995, activists have forced the government to list eight species that rely on the San Pedro, tying population declines to dwindling flows and withered riparian habitat, and thus helping to ensure would-be water users don’t cause further destruction. Building cases around those listed species, they’ve won multiple lawsuits against the fort, compelling it to decrease or offset its pumping, often by helping stormwater soak back into the aquifer.

But as more developments have descended on the river, this legal strategy has grown tenuous. In the past two years, Trump officials announced rollbacks to the ESA that, among other things, made it harder to protect critical habitat targeted for development. When I visited, the San Pedro’s advocates weren’t sure what the changes meant for ongoing litigation over the river, especially with lawsuits pending over the rollbacks themselves. (There’s now hope that President-elect Joe Biden’s administration could patch protections back together.) Even so, many had the sinking feeling that, after years of compounding strain, the river was beginning to slip beyond reach. “The ESA has made us all believers in a second chance,” Bahr says. “But sometimes you don’t get one.”
 

T

he town of Benson, Arizona, sits about 30 miles downstream from Sierra Vista, in a hot lowland valley along the I-10 freeway. A once thriving railroad stop that has dwindled to about 5,000 people, it has been offered new life by a housing proposal that envisions a Tuscan-style village spread atop a nearby scrubby mesa. Watercolor mock-ups for the 28,000-home community, marketed as The Villages at Vigneto, depict golf courses, vineyards, and cobblestone piazzas. The real estate firm financing the build, El Dorado Holdings, run by Arizona Diamondbacks co-owner Mike Ingram, has made a name for itself developing such sprawling desert communities. In Benson, one of the state’s fastest-shrinking towns, the project promises nothing short of a rebirth: as many as 70,000 new residents, $23 billion in economic output, and more than 16,000 jobs.

Vigneto appeared on Gerrodette’s radar in 2014, when El Dorado bought the land and the activists sued to block its Clean Water Act permit. She found the absurdity of it all laughable—Tuscany in Arizona?—but knew the project’s scope was too serious to write off. The issue, beyond its sheer size, was its location: Perched just uphill from the river’s west bank, Vigneto appeared to require razing dozens of tributaries and pumping around 2 billion gallons of groundwater per year. El Dorado maintained that Vigneto would be a “water-sensitive community” that, with low-flow toilets and repurposed rainwater, would use roughly half of what the Sierra Vista area consumes annually.

The Villages at Vignetto development site in Benson, Arizona, in August 2020. Ash Ponders

But in 2016 the U.S. Army Corps of Engineers yielded to the activists and suspended Vigneto’s permit pending a consultation with the U.S. Fish and Wildlife Service about the project’s impacts on endangered species. Later that year, Steve Spangle, a top FWS official in the area, determined that Vigneto’s water use would likely damage habitat for ESA-listed wildlife along the San Pedro and called for a detailed study. 

And yet, in late 2018, Gerrodette learned that the Army Corps and the FWS had reversed course, granting the permit without review. She was baffled; in all the years she’d spent investigating developments, she’d never seen a permit reissued without study, much less explanation. The following spring, after filing another lawsuit to challenge Vigneto, she learned that Spangle was claiming he’d been pressured into the decision. Spangle told the Arizona Daily Star that he “got rolled” by his superiors at the Department of the Interior, after David Bernhardt, then deputy secretary, met with Ingram in secret at a Montana hunting lodge. As CNN and other outlets picked up on the story, uncovering additional details connecting Ingram, Bernhardt, and other high-level Trump appointees, Congress announced an investigation. The local activists quickly