Reverse the flow of the Missouri and Platte Rivers and then dig a tunnel through the sub hills of the Rockies, connecting this to the Rio Grande (Providing Water from the Great Lakes). Afterward, we can cut another tunnel through the Rockies to the Colorado (Getting Water into the Rest of the South West). You can measure this is Hundreds of Trillions of Dollars. We can NOT afford it, no one can. It is a pipe dream.
If we decide to keep this strictly in the west, Digging a Ditch through the Great Basin from the Snake or Columbian Rivers would be cheaper than from the Mississippi, still in the hundreds of Trillions of Dollar for you STILL have to cut through mountains. The Same with the Missouri, the Rockies are NOT something you can ignore away.
The third option of reversing the Red River to the Rio Grande is more doable, but again expensive for most of its water comes from streams joining it as it approaches the Mississippi (This ie do to the fact that the water that flows in the Red comes from the Caribbean and falls as rain over Eastern Texas and into Oklahoma and Arkansas. Thus you just can NOT reverse flow the upper Red River, it goes not have that big a flow, you have top reverse flow the LOWER Red River and again you are looking at digging a ditch so deep that it will cost hundreds of Trillions of Dollars). The Upper Missouri suffers from a similar Situation (Through it is Further north and thus gets a lot of water do to the West-East flow of Rain Storms that is characteristics of Temperate Climates).
Now you can cut the cost of moving the water Westward by pumping the water over some of the Mountains, but this will be EXPENSIVE (Do to high energy costs) given the height you have to lift the water. Thus want you save in digging you make up in operating costs.
As you can see the problem is NOT our ability to get the water to the Southwest, but getting water to the Southwest at a price WE CAN AFFORD. To reverse flow the above rivers will bankrupt this country.
Please note the above IGNORES the problem of the height of above rivers, if you look below you will see various elevations of the above five Rivers. (Missouri, Plate, Red Rivers and the Rio Grande and the Colorado Rivers), The problem is how DEEP a trench you have to dig to get this water from the Missouri, Plate, and Red Rivers to the Rio Grande and Colorado Rivers. Furthermore the area of the Missouri, Plate, Red Rivers that can provide the needed water is so down stream and the head water of the Colorado and Rio Grande are so HIGH this si not simply a quick cut but a trench on both sides of the diversion (i.e. we will have to DIG the Rio Grande and Colorado rivers out to accept the flow from the Missouri, Plate and Red Rivers) AND to dig them to the point they are BELOW the point we started to reverse flow the Missouri, Plate and Red Rivers (Which mean almost the entire length of the Colorado and Rio Grande Rivers). This digging Adds more to the Project costs (and limiting the Effect of the Flow reversal for the water will not be able to join the Rio Grande and Colorado Rivers until both rivers are much closer to the Coast than where most of the Drought is Occurring).
When you look at a map this becomes CLEAR, The problem with the Southwest it is TO LOW (and the intervening land is to high) compared to where the extra water in the Missouri and Red Rivers is for a direct flow if these rivers were reversed. If you want to take water from the Great lakes or the Mississippi you are looking at EXTREME costs that will DOOM the project before it even starts. This idea is brought up by people who do NOT understand water flow (i.e. it flows DOWNHILL) and basic geography.
A second problem is most of the water that flows into the Great Lakes is from CANADA. This is do to the last Ice age, the Glaciers forced all streams and rivers to flow SOUTHWARD, even if they were within 20 miles of the right is now the Great Lakes. Michigan is the big exception (But it is surrounded on three sides by the Great Lakes and the Northern Peninsular is also sides on Three sides by the Great Lakes). Thus Canada will OBJECT to its water being taken instead of going through the St Lawrence to keep up shipping into and out of the Great Lakes.
Elevation above Sea Level:
River water would be diverted from:
Missouri River:
Maden, ND 1644 Feet
Pierre, SD 1484 Feet
Sioux City Iowa 1115
Omaha NE 1034 Feet (Where the Platte joins the Missouri).
Nemaha NE 886 Feet
Kansas City 750 feet
Platte River:
Park Colorado (Mountain Range from which the Platte starts) 11910
Jefferson CO, 6565 Feet
Lincoln, NE, 1890 (North Channel)
Butler NE 1440 (South Channel)
Red River:
Vernon, TX 1215 Feet
Texarkana, TX 295
Shreveport LA 210 Feet
Rivers getting the water:
Rio Grande River:
Taos NM (Rio Grande) 6565
Bernalillo NM 4951
El Paso TX (Rio Grande) 3695
Bewster, TX 1841
(Notice the Rio Grande is 3/4 through its length and almost to the Gulf of Mexico till it is low enough to take water from the highest point of the Red River where you have sufficient water flow). The Platte suffers from the same cold facts, where the Plate has sufficient water (as it joins the Missouri) the Platte is to low and the Rio Grande is to hIgh in elevation for this to work. The same with the Missouri (and that is IGNORING the distance between the Rio Grande and these three rivers, it would be MUCH easier to divert the RIO GRANDE into the Red or the Platte but that would be just removing water from the area is shortest supply.
Colorado River:
Coconino AZ (Little Colorado River) 5010 Feet
Las Vegas NV (Colorado River) 2028 Feet
La Paz AZ (Colorado River) 367 Feet
Feet Meters Location
9000 2750 Colorado headwaters (Rocky Mountains)
6100 1850 midway to Colorado-Utah border
4300 1300 Colorado-Utah border
3850 1170 midway to Utah-Arizona border
3700 1130 Utah-Arizona border (Wahweap Bay)
3000 900 midway to Grand Canyon (Rider Point)
2800 850 Grand Canyon North Rim
2500 760 Grand Canyon South Rim
1200 365 Lake Mead
600 183 after Hoover Dam
485 150 California-Nevada-Arizona border
100 30 California-Arizona-Mexico border
http://en.wikipedia.org/wiki/Colorado_River_(U.S.)
Thus to connect the Platte or the Missouri Rivers into the Colorado you have to dig from Omaha NE UNDER the Rocky Mountains to a point SOUTH of Las Vegas. This makes the diversion to the Rio Grande look a lot better but BOTH are almost physically impossible.
One last comment, the Missouri is the largest river by Volume discussed above, and it is SMALLER than the Upper Mississippi at St Louis (Where the two rivers meet to form the Lower Mississippi) and the Ohio river which Joins the Mississippi at Cairo Illinois. To get the water needed in the Southwest means DRAINING the Missouri almost completely and even that may NOT be enough (i.e. dig an even deeper trench to get water from the Mississippi itself).
http://www.graphicmaps.com/aatlas/infopage/elvation.htmhttp://www.waterwebster.com/index.htm