15 July 2021

This month a curious discovery in 2014 that predicted low water in the Colorado River and Lake Mead has come to alarming fruition. Lake Mead is going dry.

The 20 year drought in the U.S. West is now severe, shown on the U.S. Drought Monitor map below.

Consequently the Colorado River is running very low and Lake Mead reached a crisis point last month. The Guardian reports:

In June [2021], the level of Lake Mead plunged below 1,075ft, a point that will trigger, for the first time, federally mandated cuts in water allocations next year. …

Should second tier cuts occur, Arizona will lose nearly a fifth of the water it gets from the Colorado River. Nevada’s first-round cut of 21,000 acre-ft (an acre-ft is an acre of water, one foot deep) is smaller, but its share is already diminutive due to an archaic allotment drawn up a century ago when the state was sparsely populated.

— The Guardian: Severe drought threatens hoover dam reservoir and water for us west

The crisis is due to lack of precipitation but we learned in 2014 that loss of rain and snow is dwarfed by the depletion of groundwater.

Using nine years of NASA’s GRACE satellite data from the Colorado River Basin, UC Irvine and NASA scientists made an alarming discovery.  From December 2004 to November 2013 the watershed lost 53 million acre-feet of water, an amount almost twice the size of Lake Mead.  More than 75% of that loss was from groundwater.  No one knows how much water is underground but it’s going fast.

— Outside My Window: Even Less Water Than We Thought

It’s a little spooky to see such a recent discovery come to pass so soon. Learn about the discovery in this vintage blog: Even Less Water Than We Thought.

Read about the current situation at: Severe Drought Threatens Hoover Dam Reservoir — and Water for U.S. West.

(photos from Wikimedia Commons, drought map from US Drought Monitor; click on the captions to see the originals)