Source: National Geographic

Wall with Mexico

Recently, a certain GOP presidential candidate has said that the answer to America’s immigration problem is a giant wall on the Mexican-American border. Political consensus and Mexico’s willingness or unwillingness aside for the moment, how much would a wall like this actually cost?

Let’s assume that hypothetical “President Trump” would be able to get this plan mutually approved by all relevant parties. That would already be an enormous feat, since the border spans six Mexican states and four U.S. states, and has almost two dozen commercial railway lines running across it (source: Wikipedia).

The border runs a distance of 1,954 miles, across national parks, by major cities, and over various waterways (the eastern half of the border follows the Rio Grande almost perfectly). This last part is not uncommon: rivers constitute entire or partial borders in over 140 places around the world.

However, since this border runs coast-to-coast, we’d need to extend a little further than just the land-mass. Otherwise, you could take a few steps out on the beach and cross with ease. Based on this data, and I use the word ‘data’ loosely here, let’s suggest building the wall out a half-mile on either side, bringing us to a nice, clean 1,955 mile distance.

But how tall should the wall be? And for that matter, what should it be made out of? And who will build it? We’ll get to the latter two questions in a minute. The height requirement of the wall is fairly abstract: it just needs to be too tall to be easily scalable. Yes barbed wire on top looks scary, but someone willing to attempt the crazy endeavor of crossing the border into the United States of Trump is likely to be prepared enough to bring a rug. So height is our main defense.

Sadly, humans are generally not that good at climbing things (anymore?). So let’s make our wall too tall. The Lowe’s down the street sells Extension Ladders up to 40 ft. tall, so we’ll go with 45 ft. for good measure. Yes, a few capable, athletic, and determined people will still be able to make it, but in general we don’t seem to mind those immigrants. We’re making the wall this tall so we can cut all other border-related costs like customs and patrolling. Otherwise, what’s the point?

Next, material. We need something solid, strong, and able to be easily made in America instead of that other place we usually buy things from. Fortunately, America makes more cement than any country in the world except for China, India, and Indonesia. So cement it is.

Now, who to build the wall? The obvious answer in these situations is typically: cheap immigrant labor. However, I don’t anticipate laborers lining out the door to sign up for this project. So we’re faced with a dilemma. Minimum wage in the US is $7.25 per hour federally. However, New Mexico, Arizona, and California all have state-imposed minimum wages that are higher than this rate. Let’s estimate at $10 per hour average for the whole border.

The following is going to sound like on of your high school word-math problems. If we have 100 men building a concrete wall that is 1 foot wide, 45 feet tall, and 1,955 miles long, and they can build .1 mile per 5 days, how long will it take them to finish the wall? These numbers are simply an estimate, but I assume that special concrete-pouring technology will be invented (if it hasn’t already) to make this massive project slightly less unrealistic. With this (and assuming work 20 hours per day), we get a labor cost of almost $2 billion. Also, the raw material alone (no equipment included) would cost about $1.6 billion (based on $93 per cubic yard). This starts our costs off at $3.6 billion before factoring in equipment.

Although this number is likely not 100% accurate, since I low-balled the time required to build one mile of wall but am also assuming a perhaps unnecessarily tall wall, the order of magnitude seems to be right. According to homewyse, a “vendor neutral, comprehensive online reference for the house and home”, and their Retaining Wall Installation Cost Calculator, a wall of this size should run you anywhere from $8.3 to $12.1 billion.

Of course, I can think of a much cheaper solution:



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Mathew is an Economics major from Brown University with a penchant for puns and analogies (as if you couldn't tell by reading this blog). He lives in Boston with his wife, Kate, and two dogs, Teddy and Luna.

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