Someone somewhere made this point somewhere, but it is worth repeating: a good chunk of the U.S. Mexican border is the Rio Grande River. If you want to build a wall along that border, you can only build it on the Mexican side of the river if the Mexican government gives the Trump administration permission to build there. And that won't happen.
So that leaves either building it on the American shore of the river, or figuring out how to build it going through the middle of thee River. Building in the middle is going to raise all kinds of technical challenges. It will be a lot more expensive to build and maintain. And if a mid-river wall is an actual impermeable wall, it would essentially cut off water from the Mexican side of the river. That's because the Rio Grande begins inside the U.S. in Colorado, then meanders down through New Mexico before it becomes the Mexican border with the U.S. states of New Mexico and Texas. If a solid wall were built down the center of the river in the portion where it functions as a border, it would not just be a wall, it would be a dam, making the Mexican half a dry river bed. That would violate the 1944 U.S.-Mexican treaty relating to the utilization of the Colorado and Tijuana Rivers, and of the Rio Grande. Which means they would have to make a mid-river "wall" into something more like an underwater fence. (A fence might also violate the treaty. It certainly would affect the ecosystem of the river).
The only remaining possibility is to build the wall on the U.S. banks of the Rio Grande River. This is probably the only practical solution (although there still would be an "underwater wall" issue for the point where the river becomes the U.S.-Mexican border, after flowing in from the inland U.S. At that point, even a wall that is entirely on the U.S. side of the river would have to cross the river). But building a wall on the U.S. side of the Rio Grande River would essentially give the river to Mexico. Actually, that's not just an issue where there is a river. The entire border wall would necessarily leave a sliver of U.S. territory on the Mexican side, even where it is a land crossing. How would that play out politically? Not only wouldn't Mexico pay for the wall, the U.S. would effectively pay Mexico for the wall through territorial concessions. Is that really putting America first?
So that leaves either building it on the American shore of the river, or figuring out how to build it going through the middle of thee River. Building in the middle is going to raise all kinds of technical challenges. It will be a lot more expensive to build and maintain. And if a mid-river wall is an actual impermeable wall, it would essentially cut off water from the Mexican side of the river. That's because the Rio Grande begins inside the U.S. in Colorado, then meanders down through New Mexico before it becomes the Mexican border with the U.S. states of New Mexico and Texas. If a solid wall were built down the center of the river in the portion where it functions as a border, it would not just be a wall, it would be a dam, making the Mexican half a dry river bed. That would violate the 1944 U.S.-Mexican treaty relating to the utilization of the Colorado and Tijuana Rivers, and of the Rio Grande. Which means they would have to make a mid-river "wall" into something more like an underwater fence. (A fence might also violate the treaty. It certainly would affect the ecosystem of the river).
The only remaining possibility is to build the wall on the U.S. banks of the Rio Grande River. This is probably the only practical solution (although there still would be an "underwater wall" issue for the point where the river becomes the U.S.-Mexican border, after flowing in from the inland U.S. At that point, even a wall that is entirely on the U.S. side of the river would have to cross the river). But building a wall on the U.S. side of the Rio Grande River would essentially give the river to Mexico. Actually, that's not just an issue where there is a river. The entire border wall would necessarily leave a sliver of U.S. territory on the Mexican side, even where it is a land crossing. How would that play out politically? Not only wouldn't Mexico pay for the wall, the U.S. would effectively pay Mexico for the wall through territorial concessions. Is that really putting America first?
