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Faulty Design Turns Lukeville Border Fencing Into Artificial Dam

Courtesy of the National Park Service

The Southwest’s deserts are home to some of the most unpredictable flooding on the planet, and Arizona’s borderlands are no exception. Some floods happen during the days-long winter storms that soak the desert in El Niño years. But the most violent floods come in the summer monsoon season, when superheated air rises from the desert, drawing in moisture from the nearby Sea of Cortez.

The House of Representatives and then the Senate passed Representative Peter King’s Secure Fence Act of 2006, which required 700 miles of pedestrian exclusion fencing be built along the border. President George W. Bush signed the bill into law the following month. Two years later, the Consolidated Appropriations Act of 2008 required the Department of Homeland Security to finish 300 miles of that fencing by the end of that year.

By early 2008, Homeland Security had installed just under six miles of pedestrian fencing along the border near Lukeville, to ensure that migrants seeking to enter the U.S. from Sonoyta without permission had to traverse miles of unforgiving desert rather than skirting AZ 85 toward Ajo and civilization. Mindful of the threat from flash flooding, the fence was designed with wide-meshed iron grates along its bottom where it crossed washes, with 6- by-24-inch slots designed to allow water to pass more readily than the tight mesh making up the rest of the fence. During the project’s cursory environmental review, National Park Service scientists expressed concern that the grating wasn’t sufficient to prevent flooding problems. The Department of Homeland Security decided otherwise and built the fence.

On July 12 of that year, in a week in which nighttime low temperatures in Lukeville never dropped below 85°F, a series of powerful afternoon storm cells dumped two inches of rain in an hour.

When the flood reached the Homeland Security fence near Lukeville, the flood gate did not work as it was originally intended. Flood-borne debris instead plastered itself up against the base of the fence, forcing floodwaters up and over the inadvertent plug. On the downstream side of the fence, a cascade of water flowed over the debris, washing away the soil at fence’s base. Locals said the fence “acted like a dam,” backing up water as much as seven feet in some places along the fence near Lukeville.

The flood did significant damage to the Gringo Pass store, filling the entire building with water and debris. The owners eventually sued the federal government for $6 million to cover damages. The Lukeville Port of Entry on the border, and its Mexican counterpart in Sonoyta, also sustained heavy damage.

After the July 2008 floods in southern Arizona, the Army Corps of Engineers hired the contracting firm Michael Baker Jr., Inc. to assess possible threat from desert washes crossing the 600-odd miles of both border pedestrian fencing and vehicle barrier built under the Secure Fence Act and related programs. Baker’s report, provided in May 2009, was sobering.

In the area surveyed between San Diego and El Paso, Baker counted 27 washes that were capable of carrying flash floods like Lukeville 2008 or larger, which required radical redesign of the border barriers that crossed them. Another 135 washes were almost as threatening, but Baker assessed them as posing a manageable flood risk if the Border Patrol was diligent in clearing brush and debris away from the fence. (If you’re wondering who the Border Patrol would hire to do that brush hauling, you’re probably not alone.)

What redesigns did Baker suggest? Mainly that the sections of fence crossing washes prone to flood be replaced with gates that would be lifted or removed during monsoon season, or in advance of storms. In other words, make the fence less of a fence; make it more porous and permeable — and not coincidentally, less effective at keeping people from crossing the border.

Staff from the National Park Service’s Organ Pipe National Monument also produced their report detailing the extensive impacts of the pedestrian fence on the 330,000-acre monument, concluding that the fence failed to meet U.S. Corps of Engineers hydrologic performance standards set by CBP in its original environmental assessment for the project.

In 2010 the Army Corps of Engineers installed 10 such liftable gates near Lukeville as a pilot project. When monsoon season came along in 2011, someone apparently forgot to lift them. On August 7, a monsoonal storm dumped up to two inches of rain in the Ajo Mountains just northeast of Lukeville. The resulting flash flood tore out 40 feet of the new fence.

The Department of Homeland Security’s continued push to waive the National Environmental Policy Act (NEPA) and other laws on the southern border is having catastrophic effects on the environment and communities on both sides of the border. 


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