[verum ago]

Um, isn’t the elevation of Lake Powell higher than the Mississippi? That is a lot of pumping for 250,000 gallons a minute.

Lake Powell's full pool elevation is 3700' AMSL. The river elevation at the Old River Control Structure is listed as 24' AMSL. Heck, the Mississippi's source (Lake Itasca in Minnesota) is listed as being at 1475' AMSL. Insofar as I can tell, none of the MIssouri River branches / tributaries get anywhere near that elevation while still having enough flow that such a massive withdrawal wouldn't be devastating. Heck, the Mississippi River at its confluence with the Ohio (Cairo, IL) is still only at 730' AMSL.

Doing some quick back of the envelope calculations, in order to lift water at the rate listed in the article (which is 250k gallons per second, not per minute), I get a power expenditure of ~10.4 gigawatts. That assumes 100% efficiency (lol), and ignores the friction loss from 1157 miles of pipeline (great circle distance from ORCS to nearest part of Lake Mead), which would probably be in the GW range itself. (You'd definitely want to use a pipeline, or else your evaporation losses would be horrible given the climate of the lands said pipeline is crossing).

And, as other posters have pointed out, the Rocky Mountains are in the way- just spending a quick moment skimming the Santa Fe area (which aforementioned Great Circle route passes through) I can't find a route that crests at anything lower than the elevation of Santa Fe itself ~7200' AMSL. And you have to take this into account, as you can't just siphon water over the mountain range to the lower elevation of Lake Mead- since siphons work partly by atmospheric pressure, they stop working beyond the equivalent weight in a water column of the atmosphere- around 33 ft.

So to make this idea work, we're probably looking at an enormous steel pipeline well over a thousand miles long, through some very rugged country, and taking the Rocky Mountain Crest into account, requiring I would guess around 25-30 GW of power for pumping.

Simple, right?

*Sigh* but the proponents of these "Take Mississippi River water and send it to the West" projects never seem to get beyond the point of going 'Well, there's too much water over here, and not enough over here, and if I squint they're not that far apart on a map so we'll just dig a ditch. Problem solved!"

[Campion]

I get 20.6 GW required to get 250,000 gal of water per second up the 7,300 ft elevation of the continental divide. Of course you could recover a chunk of that energy, maybe 7 Gw or so, with hydro plants on the downslope end of the pipeline, so it’s not a total loss.

[AZJeep]

No, not simple, but doable!
Huge benefits. Something we can concentrate on - like the Interstate system! That was not simple either!
Definitely more useful than the fast railroads CA spends billions on.
We have just shut down the Navajo power station which could provide like 20% of the power needed.
Like I mentioned, CAP pumps water uphill like 2,200 ft. All the time. This would be like CAP X 5 project. Again, not a problem for America fifty years ago!
Unfortunately we are going downhill!
What could be done during pres. Eisenhower, cannot be done during Resident Biden!