The first problem is the Mississippi river. The bottom of the Mississippi River is already as SEA LEVEL as it flows from Missouri into Arkansas. This is the main reason it is a "Lazy, Hazy" river, it is mostly at sea level when it hit Tennessee and Arkansas. They is not that much further down it can go to reach the sea.
Worse At Minneapolis/St Paul the Mississippi is only 750 feet above sea level:
http://en.wikipedia.org/wiki/Mississippi_River
Lake Superior os 601 Feet above sea level:
http://en.wikipedia.org/wiki/Lake_Superior
Thus you have to pump water UPHILL from Lake Superior to the Mississippi River. if you decide on the short route from Lake Superior to the Mississippi River.
On the other hand, you could wait till the Mississippi River is below the Great Lakes, The Mississippi river is 350 feet above sea level when its largest tributary, the Ohio joins it at Cairo Illinois.
Side note: In proper naming of rivers and tributaries, when two rivers join, the larger by volume is considered to be the main river, the smaller the tributary. This is NOT always followed, more for historical reasons then anything else. In the case of the Mississippi, when the Ohio joins the Mississippi, the Ohio is the LARGER RIVER. Thus under proper naming the Mississippi stops at Cairo. and the Ohio flows to New Orleans. LaSalle had sailed from what is now Chicago and thus kept the name Mississippi for the river AFTER the Ohio Joins it. I mention this for it is the OHIO that is the main tributary of the Mississippi. The Mississippi is smaller in volume to the Ohio, even given the extra water provided by the Missouri river which joins the Mississippi at St Louis which is 50 UPSTREAM from the Cairo and the Ohio River.
The next major river to join the Mississippi River is the Arkansas River. The Arkansas is a major tributary to the Mississippi River. starting near Colorado Springs Colorado and flowing through Kansas then Arkansas to the Mississippi River:
http://en.wikipedia.org/wiki/Arkansas_River
The next major river to join the Mississippi is the Red River. These rivers join and do not join each other in Louisiana. The whole Mississippi River Delta is the joining of these two rivers AND the break up of the Mississippi into various streams flowing into the Gulf of Mexico. For more details look up information of that Delta.
I bring this up, for any water being pumped to the South West will have to follow the Missouri and then the Plate Rivers, the Arkansas River, or the Red River.
The biggest problem with the Arkansas and Red River is the headwaters of both are next to the head waters of the Rio Grande River. Thus any water via either river will be directed to the Rio Grande and thus New Mexico, West and South Texas as opposed to Arizona and the Colorado River.
Worse the head water of the Arkansas is 9,728 ft above sea level. Thus the water would have to be pumped over 1400 miles and then up at least 1 3/4 miles.
The Red River is formed by the combination of Buck Creek and "Prairie Dog Town Fork Red River"
http://en.wikipedia.org/wiki/Red_River_of_the_South
Prairie Dog Town Fork Red River starts at an elevation of 3,471 ft, but it itself the result of two other water streams coming together. Once you look it over, the numbers for the Red River are similar to the Arkansas Rivers, 1400 miles long and up 1 3/4 miles.
Both the Arkansas and Red Rivers borders the Rio Grande Drainage area in Colorado, the Rio Grande starts at 12,000 feet above sea level. over 2 miles above sea level. That is what you have to get over or go under the Rio Grande to get water further west (and that is if Texas will leave you, Texas wants that water also).
http://en.wikipedia.org/wiki/Rio_Grande
The Colorado River is the best route to get water to Arizona and California. Water flows naturally downhill, and the Colorado can be directed to flow into Southern California if needed. Thus the problem is getting water to the Colorado River, which starts at an attitude of 10,184 feet above sea level (i.e. about two miles high).
http://en.wikipedia.org/wiki/Colorado_River
An Alternative method is to reverse flow(or pump water along) the Missouri, Plate and South Plate Rivers. The South Plate starts its Drainage area north of the Arkansas river and thus easier to connect to the Colorado River for you can avoid the Rio Grande River headwaters. You still have to get the water over those mountains, which means pumping that water up hill at least 1400 miles AND up at least 2 miles.
Formula for Calculating price:
http://www.engineeringtoolbox.com/water-pumping-costs-d_1527.html
To pump one acre foot of water uphill 2000 feet costs 3000 kwh. To pump water up and over the Rockies we have to do at least 10,000 feet. Thus 15,000 kwh. In my home area it is about 16 cents to kwh, thus if we assume just 10 cents per kwh, you are looking at $1500 per acre foot.
Cite for 2000 KwH to move one Acre Foot of Water:
http://www.bigpictureagriculture.com/2014/02/how-much-energy-does-california-use-to-move-water.html
What is a Acre foot (please note that is what an average American use per year):
http://en.wikipedia.org/wiki/Acre-foot
The Colorado River is expected to flow 15 MILLION acre foot per year (it has not been thus the crisis). To replace that 15 MILLION ACRE Foot, that would require at least $22.5 BILLION dollars per year just in the electricity costs. That will be the costs to OPERATE the system, construction would be in the trillions.
Thus pumping the water from the Great Lakes to the Southwest is talk and always will be talk. The problem is in the details and the high mountains of Colorado is the MAIN DETAIL. The second biggest detail is the water in the Great Lakes comes mostly from CANADA, and the most of the waters in the Mississippi comes from rain the falls EAST of the Mississippi River. Yes, it is possible to move water to the Southwest, but the price will be excessive.
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