Man, this is not a joke I have proposed a mile-wide, sea level canal from Brownsville, Texas, following the Rio Grand River and the US border, all the way to Chula Vista, California. The cut would be nearly a mile deep in places, of course, but with the development of anti-gravity sleds and laser cutting beams, dumping the spoils from this earth movement into a specified site in the Gulf of Mexico, essentially building a new island on the sea floor up to the surface, and making El Paso, Texas into a major seaport by carving out a huge basin there.
Good thinkin!