Instead of a Wall, Build a Canal

What if, instead of a wall, we were to build, along the southern border, a cargo shipping canal?

The U.S.-Mexico border is 1,989 miles long; of that, 1,255 is the Rio Grande river. The Rio Grande is, at its deepest, 60 feet, but much is much shallower. The rest of the border, including a small stretch of the Colorado river, changes elevation substantially, and crosses the southernmost subrange of the Rocky Mountains. For scale, the Panama Canal is only 48 miles long, and cuts through only one little 312 foot mountain. The Suez Canal is just 121 miles long, and crosses flat ground. This would be a much, much bigger undertaking.