A dozen Democratic members of Congress are urging the Trump administration to halt plans for a new Border Patrol road across Mariscal Mountain until officials address concerns about the project’s environmental effects and potential impact on the Rio Grande.
U.S. Rep. Lloyd Doggett of Texas led the group in a letter sent Friday to Homeland Security Secretary Markwayne Mullin, Secretary of State Marco Rubio, U.S. Customs and Border Protection Commissioner Rodney Scott and U.S. International Boundary and Water Commission Commissioner Chad McIntosh.
“We ask that no work begin on road building across Mariscal Mountain until several issues are addressed and questions answered,” the lawmakers wrote. “Blasting a road across the mountain could send spoil toward, and potentially into, the Rio Grande.”
CBP maps show the proposed patrol road crossing Mariscal Mountain in the southeastern portion of Big Bend National Park, along the international boundary with the Mexican state of Coahuila. Lawmakers said construction would require blasting and extensive bulldozing in environmentally sensitive terrain.
The letter cites a 1970 international boundary agreement that prohibits construction or the disposal of excavated material from altering the Rio Grande’s normal flow. Lawmakers warned that rock and other debris could enter the narrow river channel, potentially obstructing it or changing the river’s course.
CBP awarded Southwest Valley Constructors a $1.72 billion contract May 11 for border infrastructure work that includes the proposed project.
The lawmakers questioned the road’s value to border security, noting that the Big Bend Sector recorded 148 migrant encounters in June — the fewest of any Border Patrol sector along the Southwest border. The Rio Grande Valley Sector recorded 2,227 encounters during the same month, according to CBP data.
“This poses no benefit to border security and would only cause irrevocable damage to the mountain,” the lawmakers wrote.
They said an existing road north of Mariscal Mountain is regularly patrolled and adequate for Border Patrol operations. The proposed road would sit about 1,700 feet above the border in an area where anyone crossing the Rio Grande would first have to climb cliffs rising about 1,400 feet, according to the letter.
The lawmakers also cited Southwest Valley Constructors’ work in Guadalupe Canyon, Arizona, in 2020, where they said construction debris was documented crossing into Mexican territory.
The letter asks federal officials to disclose whether a hydraulic analysis has been conducted, provide construction and debris-disposal plans, identify CBP officials overseeing the Big Bend projects and explain whether Mexican officials have been consulted. The lawmakers also requested information about payments to Southwest Valley Constructors and a briefing for congressional staff.
They requested written responses by Aug. 14.
Texas Democratic Reps. Vicente Gonzalez, Veronica Escobar, Greg Casar, Joaquin Castro, Jasmine Crockett, Sylvia Garcia, Lizzie Fletcher, Julie Johnson and Christian Menefee signed the letter. Democratic Reps. Donald Beyer Jr. of Virginia and Jared Huffman of California, the ranking member of the House Natural Resources Committee, also signed it.
