See more of the story

– President Donald Trump’s border barrier likely will require the installation of hundreds of storm gates to prevent flash floods from undermining or knocking it over, gates that must be left open for months every summer during “monsoon season” in the desert, according to U.S. border officials, agents and engineers familiar with the plans.

The open, unmanned gates in remote areas already have allowed for the easy entry of smugglers and migrants.

At locations along the U.S. southern border where such gates already are in operation, Border Patrol agents must manually raise them every year before the arrival of the summer thunderstorms that convert riverbeds into raging torrents that carry massive amounts of water and debris, including sediment, rocks, tree limbs and vegetation. Trump’s wall, which features 30-foot metal bollards spaced 4 inches apart, effectively acts as a sewer grate that traps the debris; and when clogged, the barriers cannot withstand the power of the runoff.

Because the gates typically are in isolated areas that lack electricity, they cannot be operated from afar. That requires the Border Patrol to leave the gates open for months, increasing the need for U.S. agents to monitor the sites because smugglers and other border-crossers can enter through the large gaps and advance northward following stream channels and narrow canyons to avoid detection.

The flooding risks are one of the biggest engineering challenges to Trump’s vision of a linear man-made structure spanning hundreds of miles of desert, canyons and mountains. But the Trump administration has said little about how it plans to manage the border region’s hydrology.

Though Trump has boasted that his new “border wall system” will be an impermeable force against illegal crossings and drug trafficking, the need for open gates is another notable weakness that smugglers and migrants can exploit to slip through the barrier and evade capture.

Smugglers have learned how to cut through the new steel bollards using common tools they can buy at hardware stores, and some have demonstrated that the wall can be climbed with handmade ladders and rope. Most of the hard narcotics that enter the U.S. via Mexico pass through official border crossings, hidden in vehicles and among cargo, not through the remote areas where Trump’s new barriers are being erected.

Roy Villareal, chief of the Border Patrol’s Tucson sector, which covers most of Arizona, described the addition of the floodgates as an example of how his agency has learned to adjust to the realities of the Southwest’s extreme weather and topography.

“The border is so diverse,” Villareal said. “You have to plan for water flow. … People think it’s just this monolithic wall, sort of like the Great Wall of China, where you drop it into place and that’s all there is to it. And that’s not the reality at all.”

John Ladd, whose ranch extends along the border for 10 miles west of tiny Naco, Ariz., said the Border Patrol and the U.S. Army Corps of Engineers began installing 18-foot bollards on his property in 2008, adding “lift gates” that could be opened during the summer to allow floodwaters through.

Ladd, who supports Trump and his wall project, said his border span now has about 70 gates, and U.S. agents use a forklift to raise them at the beginning of every summer. They initially were designed to be hoisted by agents using the winch on their Border Patrol vehicles, Ladd said, but the gates were so heavy that “the front end of their trucks would start lifting off the ground.”

When the gates were installed on Ladd’s ranch, smugglers would drive through the openings with loads of marijuana, he said, so the Border Patrol lowered the height of the opening to 4 feet. The vehicle incursions have stopped, but illegal crossings and smuggling increase along his property during the summer months, when the gates are left open, the rancher said.

“They know as soon as the Border Patrol opens them,” he added, referring to traffickers.