What Geology Has to Say About Building a 1,000-Mile Border Wall

Last month, President Donald Trump took steps to make good on a campaign promise to turn the United States’ existing border fence into a "big, beautiful" wall. On January 25, the White House issued an Executive Order announcing the creation of a “secure, contiguous, and impassable physical barrier … to prevent illegal immigration, drug and human trafficking, and acts of terrorism.” Now the U.S. Customs and Border Protection—the office tasked with enforcing border regulations—is scrambling to make that order a concrete reality.

Today’s fence consists of roughly 650 miles of disparate segments, made out of a combination of steel posts and rails, metal sheeting, chain link, concrete vehicle barriers and wire mesh. To replace that fence with what has been described as a 20- to 50-foot concrete structure that will traverse 1,000 of the some 2,000 miles of the U.S.’s border with Mexico will be no easy feat. Besides dealing with a proposed Mexican lawsuit and navigating the private ownership of much of Texas’ lands, there is another concern few have addressed in detail: geology.

Compared to building a marble palace or high-steepled church, erecting a wall may seem relatively straightforward. It isn’t. (Just ask the Chinese, whose Great Wall took 2,000 years to build and failed to keep out invaders.) Though most wall designs are fairly simple, builders must adapt to a wide range of terrains, explains Gary Clendenin, a senior hydrogeologist at ICF. The southern U.S. border alone contains desert, wetlands, grasslands, rivers, mountains and forests—all of which create vastly different problems for builders.

“The length of this thing presents challenges that just aren’t typically undertaken in a construction project,” says Clendenin.

Can these hurdles be overcome? Smithsonian.com asked two scientists, a geophysicist and a hydrogeologist, which geologic factors the wall’s builders should take into account first if they are to execute this ambitious project.

 

Read the full article at Smithsonian.com