I grew up in Denver, back in the 1950's. The mountains were pretty much covered with snow, at the higher elevations, year round. I remember going up to Mt. Evans one July, and getting stranded in a snow storm for several hours. We took a trip to Denver this past April, and went up to Central City, one day. I was amazed at the number of houses built along the slopes of I-70 in recent years. Decades ago, most of those houses would have been snowed in for 7 or 8 months of the year. The only snow we saw was at the very tops of the peaks, and it was melting rapidly, and filling the creeks.
Lake Powell is little more than a wide river, and Lake Mead is at its lowest since the 1930's, when it was built. The Great Salt Lake in Utah is slowly drying up. The aquifer feeding Phoenix is being increasingly depleted. If these trends continue, much of the SW will begin to resemble Death Valley.
We are very near....if not AT...the "tipping point" where there is little that we can do to reverse these trends....even if somehow all the world governments were able to come together on any meaningful changes....good luck with that.
There is an abundance of water in the Midwest and Southern states, but building the means to move some of that water West would take years, and cost trillions. Here, it's sometimes hard to find a day dry enough to mow the lawn. The millions of people living in these arid regions will soon face some major problems, and water will become the "new gold".