A federal audit of Southwest border wall construction – largely bypassing environmental protection laws – under former President Donald Trump found threats to endangered wildlife and “irreparable” damage to natural and cultural resources, including destroying a burial site and igniting explosives on sacred Indigenous sites in Arizona.

The two-year “Southwest Border” investigation released Thursday by the U.S. Government Accountability Office, or GAO, revealed that federal contractors used explosives to clear sovereign Indigenous lands to make way for expanding a patrol road. 

“The blasting damaged portions of Monument Hill, a site that the Hia-C’ed O’odham, ancestors of the Tohono O’odham, and other Tribes historically used for religious ceremonies and that remains important to several Indigenous communities,” the audit states.

Monument Hill contains the remains of Apache and O’odham ancestors who fought in intertribal battles, according to Tohono O’odham Nation officials. 

Tohono O’odham Nation leaders told federal investigators that the “damage and destruction to such sites is often irreparable because it can disrupt or end rites revered or cherished by specific cultural groups.”

Rep. Raúl Grijalva, D-Ariz., originally requested the federal audit following an outcry from communities along the border opposed to the government constructing hundreds of miles of walls and other barriers in Arizona, California, Texas and New Mexico.

The Tohono O’odham Nation is among the geographically largest tribes in the U.S. With an estimated 2.8 million acres in Southern Arizona’s Sonoran Desert, the sovereign nation stretches across the border into the Mexican state of Sonora.

Near the rugged border lies another sacred site — Quitobaquito Springs – a large desert oasis where O’odham people hold ceremonies. U.S. government contractors working on the border project “cleared a large area near the springs, destroying a burial site that the Tribe had sought to protect,” according to Tohono O’odham Nation officials interviewed by federal investigators for the audit.

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Tohono O’odham leaders were among the most vocal and vehement of communities to fight Trump’s 2016 campaign promises to build a border wall. Then Vice Chair Verlon Jose made national headlines when he told local news organizations: “Over my dead body will a wall be built.” 

Tribal members rallied to protect their sacred and sovereign lands. In 2017, Jose stood before a caravan of supporters inside a remote Topawa desert mission on tribal lands. He explained the sacred meaning of the land to his people, and the history of U.S. government officials harming ancestral sites and severing Indigenous families with border walls.

“It’s an Indigenous issue; it’s a human issue,” he said of the border wall’s impact. “This is a world issue, and we should do everything — I know we are — to stop that wall from happening.”

He recognized elders as early environmental and cultural leaders who had long balked at the construction of a wall that would endanger wildlife, land and people. “We have a responsibility to every living thing in this world,” Jose said.

In July, years after his charge against a wall he believed would have a lasting grim impact, Jose was elected chairperson of the Tohono O’odham Nation.

The new GAO audit analyzed federal agency data, plans and included interviews with government agencies. Stakeholders from Indigenous and other communities near the border construction or with expertise in resource and environmental protection along the border also were interviewed.

The audit documented instances when border “barrier construction activities destroyed many saguaro cacti in Arizona.”

In interviews with federal investigators, Tohono O’odham Nation leaders said that the “saguaro is significant to O’odham culture and livelihood, as the saguaro provides an important fruit source and is a sacred plant to be given utmost respect, as a relative.”

Saguaro cactus that did not survive transplantation in Arizona, May 2022 Credit: GAO

Many more saguaros died when federal government contractors transplanted the plants, according to a National Park Service official interviewed.

In Arizona, it is illegal to cut down a saguaro or other native plants on private land without a permit and the landowner’s permission. Violating the state law can draw a felony and hefty fines. It also is illegal to remove any plant from federal lands.

The U.S. Customs and Border Protection, or CBP, the Department of Homeland Security and the Department of Defense relied on waivers to bypass “cultural and natural resource-related laws in constructing border barriers from January 2017 through January 2021,” according to the audit.

Grijalva responded to the audit in a statement to Arizona Luminaria.

“Across the globe, there is widespread understanding that fences and walls are not an effective border security strategy — they are merely symbolic messages of hate and division,” he says. “But what makes Trump’s border wall so egregious is that his administration waived dozens of environmental, public health, cultural preservation, and even contract procurement laws to build it.”

While CBP and other related agencies, like the Department of the Interior, have made plans to mitigate the damage, the audit finds that better interagency cooperation and methods to assess the extent of the harm could improve these efforts.

Among the GAO audit recommendations are ensuring that the head of CBP works with the Department of the Interior to document a mitigation strategy that defines each agencies’ roles and responsibilities, as well as identifies costs, funding sources and time frames. The plan should also specify “when agencies are to consult with Tribes.”

Grijalva criticized the lack of federal government accountability to local constituents.

“Before construction even started, communities, tribes, and other stakeholders were raising the alarm about the colossal damage that bypassing such fundamental protections would have,” Grijalva says. “And once construction began, they were documenting the destruction through social media, local media, and any other outreach they could. It was that outreach that put this request in motion.”


In January 2017, Trump signed an executive order, calling for the development of walls and other barriers along the U.S.-Mexico border to stop migrants from crossing into the U.S.

From January 2017 to January 2021, CBP and the Department of Defense were tasked with leading the project, which resulted in the installation of 458 miles of border barriers – more than half in Arizona. The construction projects primarily replaced existing border structures, while about 87 miles of new barriers were installed where none previously existed, according to CBP data.

In his first month in office, President Joe Biden paused construction of the wall, declaring it a waste of money and “not a serious policy solution” to controlling the flow of people crossing the Southern border.

Shortly thereafter — amid concerns over the project’s cultural and environmental effects — Grijalva, U.S. representative for Arizona’s 7th Congressional District, requested the GAO investigate and produce a public audit assessing impacts of the border barriers and recommending actions to address problems or violations.

In addition to interviews with federal agencies, tribal governments and community stakeholders, GAO investigators looked at policies and agency assessments. 

Consequences of bypassing laws

The GAO found various instances of construction damaging locations of cultural significance.

The border barriers also resulted in widespread environmental consequences, including animal migration and native habitat disruption. The audit identified areas of protected lands with “significant erosion.”

A U.S Forest Service official said that a mountainside in the Pajarito Mountains on the Coronado National Forest is in danger of collapse due to the border barrier construction. Government contractors built a massive construction staging area near the top of the peak, “clearing the mountainside of its vegetation that kept the soil in place.”

“As a result, silt is draining down the side of the mountain and, according to Forest Service officials, is beginning to fill a human-made pond, threatening to eliminate it as a drinking source for cattle and wildlife,” the audit states.

GAO investigators also recorded concerns over flooding and the depletion of water resources.

According to the 72-page audit, agencies tasked with executing the project, the Department of Defense, CBP and the U.S. Army Corps of Engineers, largely relied on their authority to bypass laws such as the National Historic Preservation Act and National Environmental Policy Act to expedite construction.

Because of this, the agencies’ reviews — meant to assess and mitigate negative effects for natural and cultural resources before construction projects — didn’t meet standard legal protections.

Additionally, assessment methods varied between agencies. CBP and Army Corps officials say they did their best to meet legal standards for assessments, despite not needing to. However, the process was rushed due to the project’s urgency, according to the audit.

Meanwhile, the abrupt termination of border barrier construction under the Biden administration delayed the completion of some projects meant to guard against environmental harm. At one Arizona site, building ceased before agency officials were able to install a proper water drainage system.

Following Biden’s executive order to stop construction, DHS targeted four priorities for spending the remaining funds for border barriers: “addressing safety hazards; installing missing components, such as lights, cameras, and detection technology to incomplete portions of the barrier system; conducting project site restoration; and mitigating environmental and cultural resource impacts from barrier construction.” 

The GAO audit found agency officials have primarily focused on safety hazards. Investigators recommend interagency collaboration and delegation to more effectively tackle areas of concern.

In the course of producing an early impact assessment, CBP consulted various officials and stakeholders for feedback. The audit found that such stakeholders wanted more detailed information from CBP officials with greater transparency as to how and if the agency acts on their contributions and concerns.

One shift under the Biden administration noted in the audit may signal improved responsiveness.

For years, environmental and conservation groups, as well as government officials with natural resource agencies, have raised concerns about stadium-bright border lights being installed in areas that could harm protected species and habitat. In May, officials with the National Park Service told Arizona Luminaria they were seeking International Dark Sky Park certification for Organ Pipe Cactus National Monument.

A recent backlash from community stakeholders, over limited information about plans to nix or proceed with turning on the wave of blinding beacons in pristine desert, spurred CBP to issue a June statement to Arizona Luminaria that the agency would refer to federal standards to assess the environmental impact of the lights.

The audit confirms that effort is now underway, as well as failures in oversight.

CBP’s own assessment of potential impacts of construction in Arizona documents that the “agency did not survey the project location at the right time of year to identify many of the potentially affected species or their potential habitats,” the audit states.

Referencing the completion of unfinished border barrier projects, including lights, cameras and detection technology, the audit states CBP “has begun environmental planning” and will not award contracts until “after this planning is complete.”

Grijalva criticized Republicans for working to weaken the Clean Water Act, National Environmental Policy Act and other environmental protections. The U.S. Supreme Court’s conservative majority has sided with Republicans, limiting federal environmental and conservation powers, while boosting property and business rights.

“They are pushing bill after bill that will gut these laws just so fossil fuel and mining companies can shortcut environmental reviews and make money more quickly and easily,” Grijalva says. “But as this report makes clear, those shortcuts have major consequences, the burden of which will fall on communities and American taxpayers.”


The GAO audit recommended CBP work more cooperatively with the Department of the Interior to organize efforts to address immediate and long-term concerns due to the border barrier. The agencies agreed to the recommendation.

The audit also suggests CBP gather input and learn from the experience to improve their methods of assessing the impact of any future projects.

Grijalva took aim at the quagmire that ensues when federal agencies have divided priorities.

“The report made clear that federal land management agencies, like the Interior Department and the U.S. Forest Service, must have a major role in environmental restoration efforts,” he says. “The majority of Trump’s border wall was built on public lands, and these agencies are the ones that have the scientific knowledge and expertise to restore these lands as effectively as possible.”

The Southern Arizona congressman says he’s lobbying for transferring $225 million from DHS to the Department of the Interior and Forest Service in the fiscal year 2024 budget to aid in completing environmental restoration projects.

“So much damage has been done, but we still have the opportunity to keep it from getting worse. Environmental restoration and mitigation work is already underway, but we need to make sure those efforts are being led by science and input from the right stakeholders, including tribes and communities along the border,” Grijalva says. “So many corners were cut in building the wall — let’s not repeat history by cutting corners in restoration.”

Dianna M. Náñez contributed to this article

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Carolina Cuellar is a bilingual journalist based in Tucson covering South Arizona. Previously she reported on border and immigration issues in the Rio Grande Valley for Texas Public Radio. She has an M.S....