Cat's out of the bag. Lake Mead's water levels on the Colorado River have dropped to levels below that of the 1930's, threatening water supplies throughout the southwest. The New York Times covers this in an article that lays out the issues with the water supply for the entire region as a La Niña condition develops in the Pacific Ocean, meaning a long, dry spell.
Lake Mead, behind Hoover Dam, is downstream from Lake Powell, which is a reservoir built to back up Mead, and Diamond Valley Lake was also completed recently for emergency water storage. All of these are being drawn down, with Mead being the foremost indicator of the systemic loss of capacity.
The southwest has suffered the sharpest temperature increase in North America over the last decade, with a rapidly diminishing snow pack, loss of vegetation, expansion of forest pests, and rampant wildfires. And yet the demands for regional growth continue unabated.
The extreme climate events of this summer, known as "Global Wierding" is being reported widely throughout the press. The impact of this on food and water supplies all over the world are going to be devastating, particularly since populations are already stressing their resources. Many people sense a real danger point approaching, as these events wipe out entire regional sources of food and water. The environmental equation is tipping to a severe imbalance of natural resources and processes that provided the habitability that humanity has always taken for granted.
Partly, it's because we've treated everything as a problem in mechanics instead of systems that require replenishment and limitations on the extractions that our civilization makes from the land and the ocean. A good example of this systemic process is here in the Chance of Rain blog, with a link to the USGS database.
The best place to intimately understand this is right in our Grand Canyon, where fragile life survives in the great caverns carved by the river over the eons. What happens when the flow finally stops?