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

Much of the resistance to Drumpf’s edicts comes not from the media, or Democrats, or the millions of people who voted against him, it comes from science. You know, actual facts, not ‘alternative’ (i.e. made up) facts.

Many of the science sites I visit daily, in the US and overseas, are girding for the coming four years of assaults on the truth.

The usually apolitical Smithsonian Magazine interviewed a geophysicist and a hydrologist about Drumpf’s pipe dream border wall and they spell out quite clearly why, if it did happen, it would take years and years to finish. (And wouldn’t keep out  people any more effectively than China’s Great Wall did)

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 International. The southern U.S. border alone contains desert, wetlands, grasslands, rivers, mountains and forests—all of which create vastly different problems for builders.

“You’re going to encounter hundreds, if not thousands, of different types of soils along [such a lengthy] linear pathway,” says Gary Clendenin, a senior hydrogeologist at ICF International. (In fact, there are over 1,300 kinds of soil in Texas alone.) And many of those soils aren’t going to be the right type to build on top of. At that point, would-be wall-builders have two options: Spend more time and money excavating the existing soils and replacing them with better dirt—or avoid the region altogether.

In the case of the border wall, they would have to traverse the entire length of the proposed path, working in segments to evaluate the region, collect data, develop plans. (This necessity makes the process of erecting walls—especially ones spanning thousands of miles—more challenging than building, say, a 95-story skyscraper.)

 “Quite frankly, that would take years to do,” says Clendenin, who specializes in linear projects like railways and roads. geophysicist Mika McKinnon agrees. One project she worked on, a three-mile stretch of pipeline, is now on year five of field surveys.

One thing they can’t always avoid, though, are regions at risk of earthquakes and floods. Rivers run along a sizeable portion of the U.S.-Mexico border, which can create a very real danger of flood. Building adjacent to rivers can also present unexpected legal issues: A 1970 treaty necessitates that the fence be set back from the Rio Grande river, which delineates the Texas-Mexico border. Because of this, the current fence crosscuts Texas landowner’s property and has gaps to allow landowners to pass.

Earthquakes are also relatively common in the western U.S. Depending on the build, some of these tremblors could cause cracks or breaks in the wall, says McKinnon. One example is the magnitude 7.2 quake that struck in 2010 near the California-Mexico Border, according to Austin Elliott, a postdoctoral student at the University of Oxford whose research is focused on the history of earthquakes. “If there had been a wall at El Centinela [a mountain in northern Mexico] it would have been offset.”

Source: What Geology Has to Say About Building a 1,000-Mile Border Wall | Science | Smithsonian

About Stan Flouride

THIS BLOG IS ALWAYS AD-FREE I make stuff and do things.
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