GUADALUPE CANYON, Ariz. — The demolition crews kept right on blasting through the Peloncillo Mountains long after Donald Trump lost the election, a result that doomed their contracts. They carved steep roads at dizzying angles and gouged a wide path through the ridgeline where the border wall would go.

The clock ran out before they built it, leaving behind a mutilated landscape and a boneyard of steel fence panels stacked by the hundreds.

At more than $41 million per mile, Guadalupe Canyon was the most expensive segment of a $15 billion megaproject that ranked among the costliest in U.S. history. Today the abandoned border wall site is a liability for U.S. Customs and Border Protection, with loose rocks and boulders sliding down the mountainsides.

Sage Goodwin, whose family’s nearby ranch house rattled daily through nine months of blasting in 2020, wants the government to repair the damage to their land. He filed suit against the Trump administration and is now waiting for CBP to indicate how far it’s willing to go to put the mountain back together and prevent a flood that could wash out the road to his home.

Sage Goodwin stands alongside an unfinished segment of border wall at his family’s ranch in Guadalupe Canyon, Ariz. Washington Post photo by Salwan Georges

“We want to be reasonable and realistic,” Goodwin said. “We want to roll back the destruction and help CBP come up with a model that balances ecological values, ranching values and border security.”

In the year since President Biden halted border wall construction, his administration has been developing plans to put its own stamp on Trump’s pet project. Biden has waved off calls from activists to tear the structure down and recycle the steel. The president promised while he campaigned that there would “not be another foot,” but his government has been adding new barriers as it shores up 13 miles of flood levees along the Rio Grande and fixes other segments left in a precarious state by the contractors rushing to build right up to Biden’s inauguration.

In recent weeks, CBP officials have been soliciting input from ranchers, environmental advocates, landowners and others as the Biden administration prepares to spend hundreds of millions for border wall remediation. The money, which will include unused construction funds, will go to clean up worksites, stabilize areas facing erosion and remedy some of the worst environmental damage, while also allowing CBP to close gaps in the wall. The precise details – where and how much money – remain undefined.

CBP officials say the efforts will be focused on southern Arizona’s Tucson sector, including remote and ecologically fragile areas where the most destructive blasting occurred, such as Guadalupe Canyon, as well as the dry creek beds and channels that surge during summer “monsoon” thunderstorms. Segments of the wall were damaged in flooding last year, and erosion along the base of the structure has left its foundation exposed at multiple locations across southern Arizona.

Republicans have been clamoring for Biden to close gaps in the wall that have become busy crossing points for migrants and smugglers. In some locations those spaces are a few feet across, but they’re far wider in others, and it’s unclear what the Biden administration will consider closing a gap vs. building new barriers.

Paul Enriquez, the deputy director of the CBP infrastructure division responsible for the border wall, said the Biden administration’s remediation effort will prioritize “safety, erosion and flood control,” to ensure roads and hillsides don’t wash out and the barrier itself “does not fail and cause some sort of life safety issue for the public, local residents or agents who patrol in that area.”

An unfinished border wall construction site near Sasabe, Ariz., where crews blasted through the mountains but didn’t build the barrier. Washington Post photo by Salwan Georges

At abandoned construction sites and staging areas used to store materials and heavy equipment, CBP is preparing to clean up and replant vegetation, but officials say locations where blasting occurred can’t be easily put back together.

“We’ll be working with federal land managers to identify an appropriate restoration method,” Enriquez said in an interview. “And, in some instances where we had temporary roads installed, we’ll be remediating those areas, as well.”

Looming over Biden’s repair plan is the possibility Trump could run for office again, whipping up crowds with chants of “Finish the Wall!” and promises to bring back the bulldozers. Trump built 450 miles of new barriers during his term but had plans for at least 250 more.

Trump was unable to build in many of the areas identified by CBP as a top priority, especially along the Rio Grande in Texas. Nearly all of the land there is in private hands, and, despite placing his son-in-law Jared Kushner in charge of the effort to seize those properties using eminent domain, Trump built relatively little in South Texas.

His administration went for the lowest-hanging fruit, building along public land in New Mexico and Arizona – including national forests and wildlife preserves – that was already under federal control. Some of those remote locations had few crossings to begin with.

The barrier’s performance so far is mixed. It has funneled illegal entries and smuggling activity toward gaps and crossing points that remain open. But determined smugglers scale it with cheap makeshift ladders or saw through it with common demolition tools available at any hardware store. In Texas, the wall doesn’t stop migrants from crossing the Rio Grande because the structure can’t be built on the river, the natural border with Mexico.

Immigration arrests by CBP along the Mexico border are higher than ever. Republican support for the project appears to have further intensified during Biden’s presidency, and lawmakers have been pounding him for halting the project.

Rep. John Katko, R-N.Y., the highest-ranking Republican on the House Homeland Security Committee, said the Biden administration’s border wall remediation plan and its approach to border security, generally, are “insufficient.”

“Frontline homeland security personnel, especially the Border Patrol, are stretched far too thin and lack the resources needed to address the overwhelming and historic flow of migrants crossing the southwest border,” Katko said in a statement. “Every dollar appropriated by Congress for border barrier funding should be used for that very purpose.”

Trump obtained roughly $15 billion for the wall project, two-thirds of which came from diverted military and counternarcotics funding. The Biden administration said it will return $2.2 billion in unused funds to the Pentagon.

The Department of Homeland Security and CBP did not respond to multiple requests seeking to clarify how much money was spent on the wall and what leftover funds may be available for Biden’s remediation projects.

Biden has called the wall “a waste of money” and “not a serious policy solution,” but Enriquez, of CBP, says it remains a valuable asset.

“The barrier provides impedance and denial, and it’s one of the tools that our Border Patrol agents use in their mission to secure the border,” Enriquez said. “The administration has indicated that that’s not their policy at this time, and we respect that. And so what other methods can we use to help secure those areas?”

CBP said it continues to move forward on an environmental assessment and public comment solicitation for 86 additional miles of barriers in the Rio Grande Valley approved under Trump. But agency officials say they do not have the Biden administration’s approval to proceed with construction.

Guadalupe Canyon runs through the heart of the rugged Peloncillo range, a crucial wildlife corridor that is one of the few unobstructed bridges between the Rocky Mountains and Mexico’s northern Sierra Madre. The canyon’s large sycamore and cottonwood trees create a shaded oasis during the hot summer months.

Goodwin’s family and neighboring ranchers have worked for decades to protect hundreds of thousands of acres in these remote areas of southern Arizona and New Mexico using “conservation ranching” methods that closely manage livestock grazing and restore native habitat. Those efforts received wide acclaim after 1996 when a wild jaguar that roamed across the border from Mexico was the first to be photographed on U.S. soil in a generation.

Several other jaguars have been documented in southern Arizona since then, but many of their pathways are now potentially blocked by the border wall.

Goodwin said he and other like-minded landowners are eager to go back to an earlier era of cooperation with the government.

“We want to be a part of CBP achieving its overall goals in a way that benefits the values important to us and meets their objectives,” he said. “We have confidence there is a way to do that and not jeopardize what we’ve been working on for three generations now.”

Goodwin said he recognizes the need for barriers in populated areas but that improved surveillance technology can provide solutions in areas that should remain open to wildlife.

“The mountains are a natural deterrent,” he said. “The grade of the international border is so steep the contractors couldn’t get their equipment up there.”

In the scramble to build as quickly as possible before Biden took office, construction crews in several areas of southern Arizona skipped over locations that required additional engineering or custom wall panels. That included stream channels that need flood gates and areas at border markers that are supposed to afford CBP agents access to the south side of the barrier in case of an emergency. In other locations, crews working from opposite directions needed irregular-sized segments to fill a gap, and the panels didn’t arrive in time.

One span of the barrier east of Sasabe, Ariz., has two dozen gaps in the wall and other segments with misshapen, temporary panels welded to the structure like patches.

Myles Traphagen, a conservation biologist who has mapped and documented the impact of border wall construction using motion-activated wildlife cameras, wants the Biden administration to leave the gaps open to provide a minimal degree of safe passage for large animals.

When a Mexican gray wolf with a radio collar headed south last fall, it hit the barrier and walked parallel to it for miles before eventually turning back. The young male wolf, nicknamed Mr. Goodbar, later suffered a gunshot wound that resulted in a leg amputation.

CBP says its remediation will add more wildlife openings in the barrier, but Traphagen says they’re too small for species like wolves, jaguar, bighorn sheep, ocelot or Sonoran pronghorn to cross. “Nothing larger than a rabbit is going to use them,” he said. “It’s only a veneer of environmental compliance.”

“The majority of the remediation work they’re planning is occurring to support existing border wall infrastructure, not for ecological restoration,” Traphagen said.

On one recent afternoon along the wall east of Sasabe, a group of families with small children crossed through a gap in the wall and began trekking along the border road, looking to turn themselves in to U.S. agents and start the asylum process. Most of the families were from Nicaragua, part of a historic surge of migration from the country following president Daniel Ortega’s re-election to a fourth term last year, in elections the Biden administration denounced as fraudulent.

“We can’t live in our country anymore,” said one mother who was traveling with two young daughters. She said she was trying to get to Arkansas.

A woman calling herself Butterfly drove up to the group in a battered Honda Accord and started handing out teddy bears. She had called the Border Patrol to come pick up the families, she said. Butterfly, from Spokane, Wash., said she was with a group called Veterans on Patrol but is not a veteran herself.

“We give little gifts to the kids. We want to make sure there’s no trafficking going on,” she said, driving off.

In another area nearby where the wall abruptly ends, U.S. border agents with all-terrain vehicles, dogs and a helicopter chased a separate group that was trying to slip away into the craggy Baboquivari Mountains. After the agents left, another group of men in camouflaged clothing approached from the Mexico side, heading for another gap in the wall. They appeared to be part of a smuggling operation.

“What are you doing here?” they yelled, shouting obscenities after seeing a photographer and reporter. Traphagen, who wore a pistol on his hip which he said he began carrying after harassment from contractors’ security teams, suggested a quick departure.

Border security concerns “are real,” he said. “Human and drug smuggling are real. There is a degree of border security that is needed. The idea of having open borders is not a reality.”

Traphagen said he supports more technology along the border as well as use of smaller “vehicle barriers,” long employed by CBP to stop smugglers from driving through, which don’t block wildlife.

At some locations near gaps and open gates in the wall where he has left motion-activated cameras, Traphagen has captured images of pumas, javelina, deer and other species crossing back and forth into Mexico, but during months and months of footage, he said, not a single person appeared.

“If we can accomplish border security with a smaller footprint and more compassion toward the land and its people, I think we could start constructively trying to solve this problem,” he said.