Federal officials rectified an oversight in border wall construction Tuesday after a sharp-eyed wildlife advocate noticed the gates in the wall across the San Pedro River were welded shut.

β€œAlarm bells went off” when Myles Traphagen, borderlands program coordinator for the Wildlands Network, saw the gates welded shut Friday, as opening them during a heavy rain would thus be a β€œdaunting task.”

He posted photos online, and the Arizona Daily Star asked the Army Corps of Engineers, which oversees wall construction, about the welding Monday. By Tuesday morning, a construction worker was removing the silver-dollar-sized pieces of metal, known as β€œtack welds,” that kept the gates from opening.

Typically, tack welds are done during construction to keep gates from swinging freely open, said Jay Field, a spokesman for the Army Corps. The welds are undone when installation is complete and the project is inspected.

β€œSince construction was paused before inspections could be accomplished some of the tack welds remained,” Field said.

The removal of the tack welds was to be finished Tuesday, Field said, although some will remain on gates that have not been completely installed yet.

President Biden ordered a pause in border wall construction on Jan. 20. As a candidate, he said his administration would not build another foot of wall. While construction is paused, officials are conducting a 60-day evaluation of the wall projects.

The gates on the wall across the San Pedro River are designed to allow water to flow under the wall, which is made of 30-foot-tall steel bollards filled with concrete. The bollards are 6 inches wide and separated from each other by 4 inches of space to allow Border Patrol agents to see activity in Mexico.

Without the gates, debris such as trees and boulders could be swept against the wall, building up pressure until the bollards collapse and send a rush of water and debris down the river. Sections of shorter bollard fencing were toppled over by debris buildup near Lukeville and Nogales in the past decade.

Water levels in the San Pedro River have reached 17 feet in recent years during monsoon storms, according to a U.S. Geological Survey gauge about 5 miles north of where the river flows north across the border.

A few inches of water flowed through the river bed on Tuesday as a construction worker moved from gate to gate, grinding off the welding. He started on the eastern bank and continued into the center of the roughly 500-foot-wide river bed.

This section of border wall is being built by Southwest Valley Constructors, a New Mexico-based affiliate of construction giant Kiewit. The contractor was awarded $2.2 billion to build 88 miles of border wall in Arizona.

Customs and Border Protection officials did not respond to an inquiry from the Star. Last fall, they told a meeting of wildlife advocates, local residents and representatives from congressional offices that the plan was to keep the gates open on the San Pedro River during monsoon season. A Border Patrol agent would open the gates when heavy rains came during other times of the year.

The fact that β€œsuch a simple thing” was overlooked, led Traphagen to ask: β€œWho’s minding the store?”

Said Field: β€œWhen alerted, our guys went out and took care of it.”


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Contact reporter Curt Prendergast at 573-4224 or cprendergast@tucson.com or on Twitter @CurtTucsonStar.