Trump’s border wall scarred sacred lands, displaced wildlife and drained water. Can it be taken down?

While the long-term effects are uncertain, researchers say the construction of the wall has cut through habitats already threatened by the changing climate.

By: Erin Stone, Anton L. Delgado and Ian James

Along the southernmost edge of Arizona, where the San Pedro River once flowed freely over the border from its headwaters in Mexico, a 30-foot steel wall slices across the channel. The barrier resembles a fortress, with massive floodgates, a concrete bridge and light poles that tower over the riverbed.

Before the Trump administration broke ground on the new wall, the river and the shady forest along it had cut through the only opening in a stretch of 40 miles of fence. Now, environmentalists and others who live near the border fear for the animals that will hit an impenetrable barrier on their journeys north and south and they wonder what will happen the next time dangerous floods rush through.

The river, which provides habitat for a diverse array of wildlife, has emerged as a symbol of the ecological damage that conservationists say was inflicted when new segments of wall severed wilderness areas across the borderlands.

“Just watching that progression over the last year and a half, it’s like watching a slow death,” said Myles Traphagen, a biologist and program manager with the conservation group Wildlands Network.

Traphagen has been tracking the construction work for the past three years, watching as miles and miles of the landscape were reshaped.

Elsewhere along the border, animal tracks form a trail in the desert alongside a recently built stretch of the wall.

Gravel roads zigzag up the disfigured faces of mountainsides torn apart by explosives.

Grasslands, deserts and wetlands bear the scars of equipment that carved up the landscape. Where trees and cactuses once stood, there are stretches of bare soil scraped by construction vehicles.

A bulldozer sits parked on a road cut into a steep mountainside of Guadalupe Canyon, which was blasted to make way for the wall. A support beam props up the edge of the 30-foot steel wall while the last of the concrete dries.

In rolling hills near the border, where a well hummed for months pumping water for construction, a rocky gully now sits bone dry. The spring disappeared during one of the hottest, driest years on record, leaving a sandy streambed.

The lands were transformed during nearly four years of construction for a wall that former President Donald Trump vowed to build as a defense against illegal immigration. In flurries of work during the final months of his administration, new wall segments sprang up in some of the wildest areas of the borderlands.

By the end of 2020, the Trump administration had completed 452 miles of border wall, at an estimated cost of nearly $16 billion from U.S. taxpayers and diverted military funds. Half of that construction occurred in Arizona. When Trump left office in January, U.S. Customs and Border Protection said about 226 miles of new steel-bollard barrier had been built in the state.

The construction has cut through fragile ecosystems in some of North America’s hotspots of biodiversity, where animal species like bears and jaguars once roamed unimpeded. While the long-term effects on the environment are uncertain, conservationists say the barriers and water use have worsened conditions for habitats already threatened by the changing climate.

Now that construction has stopped, President Joe Biden and his administration are left with the question of what to do next.

Environmental activists and tribal leaders say some of the damage is permanent, from the blasted mountains to the millions of gallons of water that can’t be put back in the ground. But they believe other effects of the wall can be reversed and they want the Biden administration to go further than stopping construction.

They are urging the government to begin habitat restoration efforts and take down sections of wall that are blocking wildlife migration pathways so that animals can once again move freely. They argue that in strategic places, some of the damage can and should be undone and that it’s time to start healing these scars on the landscape where possible.

This push to remove some of the barriers faces resistance from Republican members of Congress who say they want to finish planned portions of the wall. But calls for removing certain segments of the wall have come from Democratic former Interior secretaries Bruce Babbitt and Sally Jewell.

“These are really significant, important wildlife areas,” said Babbitt, who was also Arizona governor from 1978 to 1987. “And the idea that it all requires a 30-foot wall just makes no sense.”

The Trump administration built border wall across the San Pedro River. Wildlife advocates call for opening up portions of wall so animals can cross.

On a recent afternoon, Traphagen walked along the border toward the San Pedro River, dwarfed by the newly built fencing that runs across the floodplain. His eyes were glued to his phone.

“We want data for site-specific restoration, latitude and longitude of areas that are sensitive and in need of immediate restoration,” Traphagen said. He was testing an app he and other conservation advocates are using to map out coordinates for sections of wall that they hope the Biden administration will consider tearing down.

The San Pedro River is a haven for migratory birds and wildlife, providing food and water in the arid landscape. In the past, animals like mountain lions and javelina regularly crossed through this corridor, passing through Normandy-style vehicle barriers. Those barricades, which were barely visible from afar, were removed and replaced by steel fencing, which forms a dark partition, severing the view.

This new fencing, which now stretches from Coronado National Memorial to the New Mexico state line, is impassable for many species.

Traphagen walked along the bridge and counted the floodgates — there are more than 50 on the west side of the river.

“The first thing we need to do is open these gates,” he said.

The Trump administration built new sections of wall along the Arizona-Mexico border.

An ‘ecocide’

Beside a newly built stretch of wall in the San Bernardino Valley, a wide strip of cleared land cuts through grasslands, wetlands and thickets of mesquite trees. On the bare ground beside the wall, animal tracks have cut a trail that runs east and west along the Mexican side of the barrier.

José Manuel Pérez Cantú manages land abutting the border on a cattle ranch where for years conservationists have worked to restore the ecosystem. He squatted and pointed to the tracks.

“This is probably a javelina family, going west,” Pérez said.

“We have seen a lot of tracks of wildlife trying to find a path to cross,” he said. “Wildlife is trying to find a way through, and they are not finding it.”

Pérez and his colleagues have been working to restore once-degraded lands at Cuenca los Ojos, a reserve of conservation-focused ranches, to prevent erosion and bring back native grasslands and flowing streams.

The efforts have shown success. But the sudden burst of wall construction has been a major setback, Pérez said. He described the new barrier as “an ecocide.”

Now the wall blocks many animals from searching for water, food or mates, Pérez said. Researchers have been studying wildlife on the ranch using motion-sensor cameras, and they used to see animals like bobcats and mountain lions moving north and south. Lately they see those animals looping back, unable to find a way.

“They don't know how to cross and how to get to the habitat,” Pérez said.

In one part of this border ranch, some animals once crossed to the U.S. side to drink at a windmill. When the barrier went up, Pérez and others rehabilitated an old well and used a solar-powered pump to create a water source on the Mexican side of the border.

Now animals of all sorts — mountain lions, racoons, skunks — come to drink, appearing regularly on wildlife cameras.

But the new watering hole doesn’t solve the much bigger problems for wildlife and the ecosystem, Pérez said. The barrier bisecting their habitat blocks the movement of individuals, which is vital for maintaining healthy populations.

“Diversity depends on a continuous flow of new individuals,” Pérez said. If the flow is cut off, “everything is going to be struggling.”

Pérez leads the nonprofit Cuenca de los Ojos A.C., which manages 131,000 acres across nine ranch properties on the Mexican side of the border. The cattle ranches are maintained as conservation lands and have been used by researchers studying rare species from bees to desert fish for years.

The name Cuenca Los Ojos refers to "ojo de agua," meaning a spring or waterhole, and translates as “watershed of the springs.” Parts of the land have water in pools and streams year-round, like the flowing stretches of the San Bernardino River and wetlands in Mexico just south of the lush oasis at the San Bernardino National Wildlife Refuge on the U.S. side, which attracts a rich variety of migrating birds.

In a pond a few hundred yards south of the border, American coots bobbed in the water. Other birds squawked in the surrounding mesquites and willows.

A central focus of the organization’s work has been maintaining the wildlife corridors and restoring streams and grasslands.

Valer Clark, the organization’s founder, has led the efforts to restore the watersheds. The lands were previously degraded by decades of overgrazing, upstream forest-cutting and erosion. The restoration work has involved ancient techniques building thousands of loose rock water-catchment structures called trincheras and larger permeable rock-filled structures called gabions. The structures hold back soil and sediment, prevent further erosion and help recharge the aquifer.

The construction work left a wide strip of denuded lands, which Pérez and others fear could worsen erosion.

Pérez is also concerned about water pollution from the rusting metal of the wall itself. And he worries that the illumination from the powerful lights on the wall, if turned on, could alter the nocturnal movements of insects, birds and bats.

There are also unknowns about how the construction has affected — and will affect — water sources.

Groundwater was pumped from two wells near the national wildlife refuge starting in October 2019 for construction, according to Customs and Border Protection. About 128 million gallons were withdrawn.

During an extremely dry year, Pérez said, that pumping sucked out a lot of water and left “less water running through the system.”

Over the long term, the barrier could also affect the flow of water across the border during storms. In 2014, Hurricane Odile drenched the valley and unleashed floodwaters that reached about three feet deep in places, Pérez said. He wonders what would happen in a flash flood now that the wall runs through low-lying parts of the watershed.

The border wall is reflected in the San Bernardino River, which flows to wetlands south of the border.

In the San Bernardino National Wildlife Refuge, a series of gates were built as part of the wall, which Border Patrol says it will open during large floods.

But Pérez said no one knows how those gates could be opened quickly in the sort of flood that regularly inundated the area during heavy monsoon rains.

In a big flood, he said, debris could pile up along the wall, hindering the flow of floodwaters along the San Bernardino River.

“Every creek and every arroyo has a door and a lock. Imagine the timing to open all in an event of flooding. I don’t know how they are going to be doing that,” he said. “It will be collecting more and more trees and sediment and junk. It will block the water. It will be a big concern.”

Walking along the wall, Pérez paused and rapped his knuckles on a rusting metal gate.

“We are trying to restore the natural flow of water,” Pérez said. “It’s going to change it a lot.”

When he reached the San Bernardino River, he peered at a pond on the U.S. side. The river, a small creek at that point, poured through openings in the wall, cascading with a trickling sound, and flowed on into Mexico, where thick vegetation lined its banks.

Previously, there had been only a small bridge and Normandy-style barriers here. When crews erected the wall, they pumped the river dry while they worked, Pérez said.

A large red hose, apparently left over from that work, dangled through an opening in the wall, lying in the stream.

Construction workers also laid a deep concrete foundation and Perez said it’s unclear how that barrier could affect the flow of shallow groundwater along the border.

“It’s 10 feet deep, full of concrete,” Pérez said. “We don’t know how the aquifer is going to be affected.”


Wildlife at risk

Ascending the Huachuca Mountains in southeast Arizona, golden grassland turns green, a woodland of oak and juniper. At higher elevations, the landscape turns into ponderosa pine forest. The temperature drops drastically.

“This is why this is arguably some of the highest biodiversity in the U.S.,” said Aletris Neils, a biologist who runs Conservation CATalyst, a Tucson-based group that monitors populations of jaguars and ocelots in Arizona.

In January, an ocelot was photographed in these mountains. That same month, a jaguar was photographed about 100 miles east, in another southeast Arizona mountain range.

At the top of Montezuma Pass, a scenic overlook, the black line of border wall can be seen snaking east until it disappears on the horizon. Neils looked out at the valley below, which is a known wildlife migration corridor. 

“If we don't act, we're not going to have jaguars and ocelots in the future,” she said.

In a side canyon nearby, the winds disappear and the air grows still. A sycamore grows beside several species of oak. A waist-high Yucca madrensis, which grows in these mountains and in northern Mexico, stands beside a burst of Huachuca agave. This is where north meets south, where the Rocky Mountains, Sierra Madre, and Sonoran and Chihuahuan deserts converge.

“They call this the borderlands, but I actually see it as the heartland of North America,” said Traphagen. “The black bear and the jaguar cross paths, the javelina and the coatimundi. White-tailed deer. Everything kind of occurs here. It's this meeting ground.”

Mountain canyons are important migration corridors because they provide cover, water and rich food sources. Rivers like the San Pedro are also natural migratory pathways, providing water and shade in an arid landscape.

During the Bush administration, conservationists and the federal government arrived at a compromise to use vehicle barriers, passable by most animals, instead of steel fencing in some of these corridors.

Under Trump's leadership, only about 55 miles of border fencing were constructed in areas, like remote mountain ranges, where no barriers previously existed. The rest of the 226 miles built in Arizona replaced vehicle barriers or previous types of bollard or wire-mesh fencing designed to prevent humans from illegally crossing the border, according to Customs and Border Protection spokesperson Matthew Dyman.

Now, the entire stretch of border between Coronado National Memorial and Guadalupe Canyon near the New Mexico state line, about 70 miles, is an unbroken stretch of barrier, cutting most species off from populations in Mexico.

The borderlands are the northernmost or southernmost habitats for many species. Scientists and environmentalists say this fragmentation caused by the wall could devastate genetic diversity, with cascading effects on the ecosystem.

“Things like the jaguar are charismatic and they tend to suck the air out of the room,” said Traphagen. “What I’m worried about is the everyday impacts on common species: deer, mountain lions, javelina, bighorn sheep.”

In such a dry environment, animals need more space to roam to find seasonal water sources and forage, Traphagen said, especially during an extremely hot and dry year like 2020.

“So in a time when animals need more space in order to fulfill their life cycles and needs, they’re getting that fragmented,” he said.

In its Environmental Stewardship Plan for border wall construction, Customs and Border Protection acknowledged that larger mammals, such as jaguars, could “experience the loss of genetic diversity when populations across the border are no longer able to mate.”

The plan says the new fencing includes openings for wildlife, 8 by 11 inches, placed intermittently. But conservationists say those openings, about the size of a piece of standard printer paper, are much too small for most species and that animals are unlikely to walk along the wall to find a way through.

Traphagen has already seen a drastic change in the behavior of mountain lions in the San Bernardino National Wildlife Refuge. He has been monitoring the area using trail cameras since last year and has been tracking construction since it began.

Before the wall, mountain lions often passed from north to south. Now they're blocked.

“I think what they’re doing is they’re coming down, there’s the wall, they pace back and forth and then go back and they just keep repeating this same cycle,” Traphagen said.

Sky Island Alliance, a conservation group that focuses on the borderlands, has been studying wildlife along a stretch of the border since last March. So far, the group has photographed 106 species with trail cameras at 58 sites on both sides of the border.

“We didn't expect to have more than a hundred species within the first six months of the study,” said Emily Burns, program director for the group. “That was just really exciting to us. We knew this is a highly biodiverse region, but it's been so fantastic seeing the number of species that are present.”

They’ve captured images of North American porcupines, whose southernmost range is in the borderlands, as well as white-nosed coati, a subtropical mammal whose northern range is in Arizona.

“The border wall could really isolate a smaller population of coatis in the United States from the core population,” Burns said.

In southern Arizona, the decline of the endangered Sonoran pronghorn serves as an example for how fragmentation can devastate a species.

In the early 2000s, a combination of border wall construction, development, drought and the expansion of Highway 2, a major interstate just south of the border, reduced the U.S. population of pronghorn to just 25 individuals. There was still a healthy population of 600 in Mexico, but the U.S. group could not maintain genetic diversity because they could no longer cross the border.

To salvage the species, scientists started a captive breeding program in 2004. Now there are about 460 wild Sonoran pronghorn in the state, according to John Hervert, Arizona Game and Fish Department's lead for Sonoran pronghorn recovery.

“We know that one of the biggest causes of mortality for the Sonoran pronghorn is that they were having trouble getting across the border even before the wall went up because of the traffic on Mexican Highway 2,” said Gary Nabhan, an ecologist and author who has worked extensively in the borderlands. “Now we have a 30-foot wall. Those are basically two isolated populations now.”

Nabhan worries that many species could face the same fate with the new border fencing.

“There's this anxiety because we don't know what's going to happen and how fast,” said Nabhan. “How does that affect plant populations or an animal population that was virtually cut in half by the fence? And how far does that effect ripple away from the border itself?”


Groundwater pumping for the wall

On Jan. 19, the final full day for the Trump administration, crews were still at work in the Coronado National Memorial. Heavy machines were carving a road into a steep mountainside by the border.

The sounds of construction echoed through the grasslands, the beep-beep of trucks as they dumped boulders and sent them clattering down the hillside. A water truck chugged its way up the zigzagging road, spraying the dirt path with water to keep the dust down.

Nearby, a generator hummed beside a well, sending water pouring through a thick hose to a storage tank for construction.

Looking through binoculars, Zoe Fullem followed the water truck as it climbed toward the peak.

She walked toward a spring, passing through trees. Reaching the streambed, her boots sank into dry sand. Fullem, community science manager for Sky Island Alliance, hasn’t seen any spring water here since the summer of 2020.

Fullem said it’s not clear how the groundwater pumping might have affected the spring. But the pumping, coupled with the dry year and the effects of climate change, only increases her concerns.

“In such a dry place here, in the Sky Islands, springs are a really, really important source of perennial water for wildlife,” said Fullem. “Our data shows all sorts of wildlife use this water for drinking during times of the year when there aren’t any other water sources in the area.”

Data from Customs and Border Protection shows that at least 463 million gallons of groundwater were pumped from 24 wells along the border for construction purposes during the 2020 and 2021 fiscal years. For comparison, roughly 4,200 single-family homes in the Phoenix area could use that amount of water in a year. Three Arizona golf courses with average water consumption would use slightly more.

The agency’s environmental plan says the groundwater pumping could “have moderate to major adverse impacts on the availability of water resources in the region.”

But the effects of pumping haven't been well studied. And the government waived multiple environmental laws, so the effect of construction on springs and aquifers can only be speculated.

The spring that Fullem visited hasn’t had water since September.

Brit Rosso, a former National Park Service employee who volunteers for the Sky Island Alliance, previously saw flowing water and pools here where animals would come to drink. Rosso stood on the dry streambed, where he has been coming regularly since 2019.

“I’m disheartened but still optimistically hopeful that we’re going to see water here again,” Rosso said. “There are so few water sources as you go through here for wildlife. So, if they’re not getting it here, they’re going to have to go somewhere else and find water.”

After surveying the spring and recording his observations on a tablet, Rosso walked uphill to another water source, a seep that formed a muddy puddle among bushes and deer grass.

“This is providing a little sliver of life, of water, for wildlife,” Rosso said. “That’s just so encouraging.”


Mourning damage to the land

The Nde benah, or Traditional Territory, of the Chiricahua and Warm Springs Apache, two of four western Apache bands, span from the San Pedro River to the Rio Grande Valley, from northern Mexico to Interstate 40 in Arizona and New Mexico. Traditional lands of the O’odham — Tohono, Akimal, Ak-Chin and Hia-Ced — extend from the San Pedro to the Colorado River, from Phoenix to Hermosillo, Sonora.

The Apaches and O’odham long passed freely between what would later become the United States and Mexico.

“This is where we were created and so this land to us is life and death,” said Joe Saenz, a Warm Springs Apache descendant and current Nantan, or president, of the Chiricahua Apache Nation, headquartered in southwest New Mexico and not yet recognized or acknowledged by the U.S. government.

Like many borderlands tribes, the modern division of Apacheria, the lands inhabited by Apache peoples, began with the end of the U.S.-Mexico War in the mid-1800s, when the Treaty of Guadalupe Hidalgo and the Gadsden Purchase drew a new line on the map. That didn’t stop Apache resistance as they fought off a genocide that didn't end until 1886, when Geronimo, the famous Apache leader, surrendered in the Peloncillo mountains in southeast Arizona.

Many Apache were forcibly resettled on the San Carlos reservation farther north. Others were forced from the Traditional Territory, eventually displaced to the Fort Sill reservation in Oklahoma. But many, like Saenz’s ancestors, escaped to the Sierra Madre mountains in Mexico, remaining on the land they believe the Creator, Yusen, made for their people and their animal relatives.

The latest iteration of the border wall is yet another insult to the injury of that violent history, said Bill Swims After His Horses Bradford, the Nation’s attorney general, and shows a failure of the U.S. government to uphold its legal obligations under treaties negotiated in the mid-to-late 1800s.

“Our relationship with this land is very intimate,” said Saenz. “The only way to describe this wall is like a hatchet to our body that cuts us in half. What we have been experiencing and what this land has been experiencing, it's pretty severe, pretty violent. And we see a very strong need to correct this.”

The Chiricahua were ignored in discussions about wall construction, but they hope the Biden administration will better engage with tribes. Even if there is more robust consultation, the Chiricahua and O’odham tribes say much of the damage has already been done.

Construction at O’odham sacred sites, like Quitobaquito Springs, has sparked outcry. Blasting of Monument Hill to make way for newer, taller barriers near Organ Pipe Cactus National Monument has disturbed burial sites.

“Get a knife and cut across your chest and tell me if your chest is ever going to be the same,” said Verlon Jose, former chairman of the Tohono O’odham Nation. “Yes, it will heal, but there's going to be forever a scar there.”

There is an intimate connection between land, humans and animals in O’odham and Apache culture. It’s a reason the scars on the landscape have been particularly painful for them to witness. Some Chiricahua Apache say the wall is as much a desecration to their land as the Mount Rushmore monument is to the Lakota.

The Chiricahua consider all of their Traditional Territory sacred and their creation stories describe specific relationships with different animals. For example, the bear is highly respected and is not allowed to be hunted or touched. The coyote teaches the importance of balance in the ecosystem. Cutting off migration corridors puts these animals and the ecosystem at risk, Saenz said.

“We can't separate ourselves from the environment, the animals,” Saenz said. “That’s what I foresee with all of this, that it's going to bleed into the air, the water, the animals, sooner or later.”

At the western edge of the Apaches’ ancestral territory, about 12 miles from the border, Sandy Anderson lives on land she bought in 1984. When Anderson first arrived, the property was filled with junk cars and garbage, but she said she saw it for what it could be.

She and her then-husband restored the grassland and trees. In 2001, she founded the nonprofit Gray Hawk Nature Center, and her home became a learning center for children. Now her back yard is part of the San Pedro Riparian National Conservation Area, a 40-mile federally protected stretch of the river.

Anderson has led thousands of school kids along the river, teaching them about native wildlife and plants. She’s rescued or inherited dozens of reptiles, including a five-foot western diamondback, a skink and a Gila monster. She has two adopted wild horses that she trained herself. She befriended a roadrunner named Clack “that loved me unconditionally.” He was recently killed by a hawk. She wears one of Clack’s feathers in the band of her hat.

Over the years, Anderson has watched monsoon floods swell the river to her doorstep. She thinks one good flood will knock out the 30-foot wall that now cuts across the river. Still, she worries for the effect on wildlife.

“It is a travesty, a tragedy, against the natural world,” Anderson said, walking along the riverbank about 100 yards from her house. “It should have never happened. It has got to be fixed.”

Anderson is saddened by what’s been lost in places like Guadalupe Canyon, where much of the damage is irreversible.

“The mountains, they’ll never heal, not in many, many lifetimes,” Anderson said. “It literally is like having your heart ripped out for no reason. That wall stops everything but what it was intended to stop and the degradation that it has wrought on the landscape is incalculable.”


Removing ‘strategic segments’

Now that long stretches of wall are built, nearly 70 conservation groups on both sides of the border have been discussing ways of restoring habitats and blocked wildlife crossings. Their proposal lists 13 segments in Arizona they say should be removed or modified, from Organ Pipe Cactus National Monument to the Peloncillo Mountains at the New Mexico state line. Defenders of Wildlife, one of the groups that signed the proposal, published its own report based on this work.

These organizations are demanding that about 58 of the 226 miles of new fencing be removed and the land restored.

But not everyone agrees. The Malpai Borderlands Group, a coalition of ranchers and environmentalists in southeast Arizona, declined to sign the proposal, saying it didn’t fully address all their concerns, particularly about security.

“We don’t think it addresses the security issue at all and that needs to be addressed. The fact of the matter is the wall hasn’t made the border any more secure,” said Bill McDonald, a fifth-generation rancher and founder of the group. “To me security is the number one thing and then you worry about wildlife migration, things like that.”

McDonald said the unfinished sections of the border wall pose a security risk and that the conservation groups’ proposal doesn’t address this issue in the areas where they think the wall should be removed. A wall was never the answer for McDonald; it was just “a political thing and I think that’s played out.”

Another proposal by the Borderlands Restoration Network, a nonprofit partnership of U.S. and Mexico-based conservationists, argues that restoring bladed land and blasted mountains using erosion control structures and native plants are immediate steps to mitigate damage.

One floodgate stands open on March 14 in the border wall that built across the San Pedro River in southeastern Arizona. Conservation advocates have urged...

They also want to see floodgates opened at waterways like the San Pedro. At least one of the floodgates was seen wide open at the river on March 14, and conservationists hope to see more of them permanently unlocked and pushed aside.

Ultimately, they want the restoration to be more holistic, a way to address unemployment and support healthy cross-border relations.

“The wall should be removed in selected places. We're not talking about a massive tear down… we think that ought to be done very carefully and with a lot of thought as to what the security concerns are,” said Ron Pulliam, an ecologist and founder of the network, who co-authored the proposal.

Clark, the founder of Cuenca Los Ojos, said in some areas, the techniques she has used can help restore the land. She said building rock structures that help prevent erosion is one way to address cleared areas that are prone to flooding.

“The only thing you can do now is try and avoid massive erosion problems,” Clark said. “When you scar up a mountainside so that there's no vegetation, nothing left, you really don't know until the first big monsoon what's going to happen.”

In February, Babbitt and Jewell, the former interior secretaries, said in a letter to Biden that they believe “a new approach is desperately needed, one that restores degraded lands and waters.”

Babbitt and Jewell signed the letter along with 26 conservation advocates, tribal leaders and others, calling for removal of “strategic segments” of the wall. They’re urging the administration to “mitigate the worst impacts of the border wall by reopening critical wildlife corridors, restoring riparian habitats, and healing the scars of construction before seasonal monsoon rains make the situation much worse.”

They also called for employment opportunities to restore the borderlands as part of Biden’s plans for a Civilian Climate Corps.

“Federal investment in a restoration economy will benefit both people and nature, with returns far exceeding program costs, and improve the United States’ relationship with our southern neighbor and close ally,” Babbitt and Jewell said in the letter.

If left unchanged, the environmental damage from new sections of wall will accumulate over time, Babbitt said in an interview.

“It's time now to step back from this pell-mell," Babbitt said. "We're going to wreck everything without regard to any kind of environmental impact. Step back and pause and analyze all of the tradeoffs in terms of, are all of these stretches necessary? The answer, I think, would be clearly no.”

In Arizona, the desert bears the scars of equipment that carved the landscape.

Babbitt noted that barriers have walled off the border in many areas for decades, and he said he thinks there are places where having those barriers makes sense.

“But what happened here is they just went ahead and said, ‘We want a barrier all the way,’ irrespective of the tradeoffs and the actual necessity and the damage to the environment and wildlife corridors,” Babbitt said.

“Those decisions, those tradeoffs have never been discussed,” he said. “And that, to me, is really the beginning point for the changes that ought to take place.”

The majority of the U.S.-Mexico border in Arizona falls in the district of Rep. Raúl Grijalva, D-Ariz., who has been a vocal opponent of a physical border barrier since before a 30-foot wall became one of Trump’s signature campaign promises.

While he supports wall removal, Grijalva, who also serves as chair of the House Committee on Natural Resources, said the first step has to be a scientific study on the wall’s effects. He said he thinks a study would prove that the wall “is unnecessary and does quantifiable damage to the environment and the people of the borderlands.”

In 2019, Trump declared a national emergency at the U.S.-Mexico border, saying it “presents a border security and humanitarian crisis that threatens core national security interests.” This paved the way for the administration to issue dozens of waivers, bypassing environmental and cultural laws.

The controversial executive power was made possible after the Sept. 11 attacks, when Congress granted then-President George W. Bush the authority to sidestep the laws to speed up border wall construction on the California-Mexico border. The waiver authority wasn’t limited to that period of time, so the Trump administration used it to accelerate border wall construction during his term.

Grijalva said he’d like to see those environmental waivers repealed and he expects that will be discussed in Congress.

Reflecting the deep political divisions on the issue, Arizona Attorney General Mark Brnovich filed a lawsuit against the Department of Homeland Security this month arguing that, in halting construction, the Biden administration flouted compliance with the National Environmental Policy Act.

Environmental activists have said construction continued past the seven days to wind down allowed by Biden’s presidential proclamation.

As of Jan. 19, there were approximately 18 miles of incomplete new border barrier in Arizona. The additional work was related to making incomplete sections safe, including transporting heavy machinery, storing and securing materials and preparing sites to stop work, CBP spokesperson Rob Daniels said in an emailed response to questions from The Arizona Republic.

Work near Walker Canyon in the Pajarito Mountains “was delayed for more than a week due to inclement weather,” Daniels wrote. “If this area is not stabilized, there is a serious risk of slope failure causing both safety and environmental issues if left as is.”

In some areas, the 30-foot fencing comes to an abrupt halt, leaving an open border where vehicle barriers were shoved aside or mountains bulldozed for a wall not yet built.

For example, near the town of Sasabe, 20 foot gaps in fencing were blocked by barbed wire or stacked bollard fencing that had not yet been erected. A small mountain at the end of the segment had been blasted through, its steep face now sandy and bare.

If conservation advocates have their way, this section of wall — along with other parts across Guadalupe Canyon and the San Pedro River — will come down.

A year ago, the San Pedro River, flowing north from its headwaters in Mexico, passed quietly into the United States under a steel bar across the riverbed. Border patrol agents parked their trucks on either side of the river.

On a wintry afternoon, an agent sat in his truck, his tattooed arm hanging out the window. He was a combat veteran, he said, and he liked patrolling the river. It was mostly peaceful and serene, a far cry from the chaos he had experienced in Iraq and Afghanistan. He’d even seen a few mountain lions slink across the border at night.

That day, there were signs of what was to come. Pink flags were tied around a dozen or so cottonwoods. The words “remove trees” were scribbled on small wood posts placed in front of them.

A year later, those cottonwood trees are gone. Thirty-foot fencing has replaced the Normandy-style vehicle barrier in the riverbed. The dirt patrol road is now a cement bridge. Light poles 100 feet tall loom above the remaining cottonwoods. Boulders cover the ground below.

In early February, the river flowed through a 15-by-20 foot floodgate, its steel bars reflected in the calm, ankle-deep water. For a few yards, the river disappeared under the rocks. Then it reemerged, continuing on its northward path.