Heading image: The tall bleached “bathtub ring” is visible on the rocky banks of Lake Powell on June 24, 2021 in Page, Arizona. Photo: Justin Sullivan (Getty Images)
You may have seen images of dried-up lakes and reservoirs in the American Southwest but might not realize that this particular drought recently ‘celebrated’ its 22nd year—a mind-numbingly long time for a part of the country to experience severely below-average rain/snowfall. This drought covers the vast area from Montana to Northern Mexico on the north/south axis, and between the Pacific Ocean and the Rocky Mountains when measured east to west. You can see it most clearly in Lake Mead and Lake Powell, the two largest reservoirs in the US. Lake Mead is now filled to just 35% of its capacity, its lowest level since April 1937. Lake Powell is in even worse shape, filled to just 31% of capacity.
Scientists looking at tree ring data have now concluded that this is the most severe drought in this region going back at least 1,200 years, and that 2002 was the second-driest year since 800 AD. (The year 1580 was apparently the driest on record.) The record-low rainfall, and reservoir levels, are particularly troublesome because they represent the primary fresh water source to the cities of San Diego, Las Vegas, Phoenix and Los Angeles—plus some 4-5 million acres of farmland all over the Southwest. Under an emergency allotment agreement, Arizona will have to make do with an 18% reduction in its total water use, while Nevada and Mexico are going to experience a 7% and 5% water reduction, respectively.
Of course, droughts eventually end, right? Unfortunately, this one may be with us a while longer, forcing additional water-tightening measures and some pretty dramatic future headlines about severe water shortages. Based on computer models, there are forecasts estimating that the Lake Mead and Lake Powell reservoir water levels are going to drop an additional 34 feet over the next two years.
Sources:
https://gizmodo.com/american-southwest-is-experiencing-worst-drought-in-1-2-1848536119
https://earthobservatory.nasa.gov/images/148758/lake-mead-drops-to-a-record-low