Natural and cultural resources in the Organ Pipe Cactus National Monument, 517 square miles of mountain ranges and desert land, would be put at risk from the building of the wall, the park service determined in a remarkable report that raised questions about one of the president’s most cherished policy initiatives.

Scientists have found stone tools, rock shelters, artifacts and ancient engravings in the area, which has been populated for 16,000 years. That includes Quitobaquito Springs, where ancient cultures obtained seashells and salt along what is known as the Old Salt Trail.

The National Park Service found 17 archaeological sites that “likely will be wholly or partially destroyed by the forthcoming border fence construction.” An additional five sites that park experts want protected under the National Register of Historic Places could also be damaged.

Artifacts that have yet to be discovered “will be destroyed over the course of ensuing border wall construction,” the report said. The wall is expected to be constructed over a section of the southern border of the national park called the Roosevelt Reservation, “an area of great concern, whose cultural and natural resources are imperiled,” according to the National Park Service.

The unveiling of the report, first obtained by The Washington Post, highlights how the construction of Trump’s border wall can cause the efforts of one agency to undercut the mission of another. While the Department of Homeland Security has primarily become an immigration enforcement agency under the Trump administration, the National Park Service remains responsible for preserving the land that is guaranteed to be damaged by Trump’s barriers.

“Each day, we learn new ways President Trump’s wasteful wall will destroy the land near the border,” Rep. Bennie Thompson of Mississippi, the chairman of the House Homeland Security Committee, said in a statement. “It is clear that the environment and historical sites around the border area are extremely sensitive. Even replacing currently existing fence could permanently damage these areas.”

In recent months, Trump has pressured homeland security officials to speed the construction of his border wall. After the Supreme Court ruled in July that the administration could use $2.5 billion in Defense Department money for the construction of the wall, Customs and Border Protection and the Army Corps of Engineers began building about two miles of barriers a week.

Trump has promised that 500 miles of wall would be erected in his first term. So far, his administration has built 66 miles of replacement fencing or barriers, largely in areas where dilapidated impediments already existed.

The agency has also been able to waive environmental protection laws that would require the administration to produce an in-depth environmental impact analysis and perform environmental monitoring after construction.

Environmental experts said the construction of the wall will affect more than just the archaeological sites identified in the report. The unearthing of the area surrounding the barriers and the installation of lights on the wall will devastate wildlife and contaminate cultural lands, they say. The Organ Pipe Cactus Monument is sandwiched between the Cabeza Prieta National Wildlife Refuge and the Tohono O’odham Reservation. Leaders of the Tohono O’odham say the border wall would virtually split the indigenous community in half.

Laiken Jordahl, a borderlands campaigner at the Center for Biological Diversity, said the wall would lead to “the severe degradation of Organ Pipe as a whole.”

“The lights that will be installed on top of the wall, blasted into the wilderness, the ground water being sucked up — it’s more than just a border wall,” said Jordahl, who used to work on the memorial. “All of these activities will just increase the desertification of the region.”

Jeremy Barnum, a spokesman for the National Park Service, softened the tone of the critical report on Tuesday. In a statement, he said that because of the location of the southern border, “a handful of parks are challenged with managing impacts stemming from various cross-border illegal activities.”

“As such, the National Park Service works closely with the Department of Homeland Security to provide for life and safety and to protect monument resources,” Barnum said.

The National Park Service website also highlights that the Arizona park was exposed to damaging illegal border crossings and smuggling in the 1990s and early 2000s.

The Army Corps of Engineers is replacing the vehicle barriers and fencing along the 30-mile southern border of the Organ Pipe National Monument with a 30-foot-tall steel bollard fence, according to the park service report, which involved five days of field work in June.

Kevin Dahl, Arizona senior program manager for the National Parks Conservation Association, said Trump’s campaign promise would harm not only the archaeological sites but also the tribal lands.

“Many of these archaeological sites were produced by the ancestors of people who still live in the area and have great concerns about the impact of the wall on their sacred space,” Dahl said. “It’s not going to reduce drugs or immigration of asylum-seekers. It’s just pretty wallpaper to fulfill a campaign promise that should have never been made.”

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