Down to the Salton Sea, it's surface sits 65m below the Gulf of California. You dig a 200m wide canal and massive network of locks, all you've done is build a half trillion dollar shortcut from the Colorado River to the Coachella valley, an area with no infrastructure.

Or you could build a 20 mile tunnel from the Port of LA/Long Beach to offload the road network. I even know a local guy with a tunnel boring machine company.