The natural flow of the Colorado river should be around 20,000 cubic feet per second

The Columbia river dumps 265,000 cubic feet per second of fresh water into the ocean! Over 10 times what the un-interrupted flow of the Colorado should be!

My idea is the best and everyone else's is terrible! (just kidding) but honestly they do not need to pump much, just dump a small portion of the Columbia into a pipe near Portland, lay 1000 miles of pipe on the ocean floor to LA with no tunneling needed and very minimal disturbance to any ecosystems and if there is a leak big stinking deal as that fresh water was just about to end up in the ocean anyhow. The only pumping needed would be to pump it out of the southern end of the pipe into the LA water plant or a reservoir or something. If you try to get it from the other side of the Rockies you will need at least 1500 miles of pipe, drilling through mountains and under or over roads, securing right of ways, pumping it up hill several thousand feet takes a lot of energy, that's how we make so much energy damming it up and letting it fall a couple hundred feet. This plan frees up the portion of Colorado river water going to southern California cities so Phoenix and Vegas can have more, heck we could probably get Mexico to chip in some of the cost if we let some more of the Colorado flow into Mexico.