The NY Times Sunday Magazine had a very interesting article about the challenges facing the American West with the combination of booming population growth and ever decreasing precipitation. I found two points particularly interesting.
One, that the water rights treaties that divide up the river waters out west were based on assumptions that flows in the Colorado River were average at the time. It turns out that those flows were probably much higher than average and the flows we see now are probably much more accurate.
Two, that Aurora, Colorado is starting construction on building some wells ~30 miles downstream on the South Platte River, which is also downstream of the outfall of their wastewater treatment plant, and then pumping it back to Aurora. They bought the water rights there from some farmers, but essentially, they are planning on recycling their wastewater for use as drinking water. What better way to guarantee flows in the river!
Photo of Lake Mead (100 feet lower than it used to be) from The New York Times