Posted on November 16, 2007

A Fence Without Offense

Richard Marosi, Los Angeles Times, November 16, 2007

A crew of U.S. Border Patrol agents, sweating under a hot Texas sun, squared off against an array of formidable-looking frontier fences.

They swung axes at posts, used blowtorches to melt steel, tore through sheet metal with crow bars and scaled walls with ladders.

Government engineers working with the agents rammed remote-control SUVs loaded with 10,000 pounds of sand into the barricades at 40 mph.

The agents drew on secrets learned from smugglers. The engineers had decades of expertise designing defenses for nuclear stockpiles.

Together, in a nine-week project called Fence Lab, they were trying to solve one of the nation’s most vexing problems—how to find fencing strong enough to protect the U.S. from one of the largest human migrations in history but sensitive to the fact that Mexico and the U.S. are friendly nations.

Consider the government’s requirements.

The fence must be formidable but not lethal; visually imposing but not ugly; durable but environmentally friendly; and economically built but not flimsy.


The largest fence expansion in the history of the southwest border is well underway, with more than 70 miles erected this year and 225 planned for 2008. Often lost amid the debate over how to control the border is the thought process behind the physical barriers themselves.


In the shadow of the Huachuca Mountains in Naco, Ariz., a double-layer steel mesh barricade stretches across the frontier like a sheet of honeycomb netting. Alongside small towns in California and Arizona, tall steel tubes form what look like giant picket fences. Outside Yuma, Ariz., a wall of steel plates burns hot as a skillet in the desert heat.

Fence design is constantly evolving. The mesas and canyons along the San Diego-Tijuana border form a sort of museum of the successes and failures.


None of the new generation barriers have angled parts or horizontal slats. Most of the newer fencing is transparent because border agents complained that the solid steel mats blocked their view of smugglers staging crossings in Mexico.


Proposals had to meet certain specifications. The barrier had to be 15 to 18 feet high. It had to be able to withstand the impact of a vehicle moving at 40 mph. It had to be strong enough to keep smugglers from cutting through it in less than 15 minutes. It had to be “aesthetically pleasing” and able to be erected at a pace of at least one mile per day.


In all, the government tested nine barriers at Fence Lab, held at the Texas Transportation Institute at College Station.

Tight security—no cellphones, no cameras, no private contractors as witnesses—aimed to ensure that information about construction methods and raw materials would not be leaked to smuggling organizations.

The dozen or so Border Patrol agents on hand came from the fence crews that roam the border to patch, weld and make other repairs to torn-up barriers. The engineers from Sandia National Laboratories, a Department of Energy research and development lab with Cold War-era roots, called the agents “the red team.”


In other words, the red team attacked—with battery-powered saws, grinders, fire axes and ladders taken from Tijuana human smugglers. One by one, in a matter of minutes, they reduced the fences to tatters. The engineers hadn’t expected that.


The results did not mean the designs were scrapped. At least one fence similar to a tested one has since been erected. The goal, experts say, isn’t to find a barrier that can’t be breached.

“There’s nothing that’s impenetrable, no material that can’t be cut given certain time frames,” said Rowdy Adams, a Border Patrol chief.

The idea is to develop fences that slow down illegal crossers, agents say, allowing time to stop migrants before they disappear into border communities, known as the melt zone. At Fence Lab, the designs deemed most promising took the longest to conquer.


Hollow steel tubing, once easily cut by blowtorch-wielding smugglers, is now filled with concrete. Immigrants still get through it, but it takes time because they have to use slower-cutting saws. Rectangular posts have given way to harder-to-climb rounded ones. Fencing has grown taller.

In urban areas where the melt zone is just a quick dash from the border, layers of barriers are erected to make that dash much harder.

In San Luis, Ariz., migrants who scale the landing-mat fence now find themselves blocked by a newly installed secondary barrier made of steel mesh. The mesh is a favored material because of its tight cross-hatch pattern, which makes it difficult to find a toehold for climbing. It was recently put up along 32 miles east of San Luis, the longest stretch of continuous fencing on the border.

In rainy areas, however, mesh and solid-steel fencing won’t do because they impede water flow and can cause flooding. That’s why in places like the monsoon-drenched Altar Valley south of Tucson, the government is placing tall steel tubes four inches apart, gaps too small for people but big enough so that water can flow freely.


One of the Fence Lab barriers that agents seem to like best so far is a double-mesh barrier made of thick welded wires in a tight honeycomb-like design. The tiny holes between the wires make climbing difficult. Axes and crow bars are useless because the layers give under pressure. Blow torches get through, but it takes more than 15 noisy minutes to cut both layers.

Still, this summer a similarly constructed double-mesh fence went up along seven miles of border in Naco, Ariz., and within days Mexican smugglers had found a way to defeat it. By inserting screwdrivers into the holes to use as handholds, they are able to scale the fence as if it’s a pegboard.


After all, said Agent Sean King, based in Tucson, only the most athletic migrants possess the strength to pull themselves over with screwdrivers, and they can’t do it en masse.