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  • Writer's pictureMark L. Johnson


Aridification is the process whereby a region becomes increasingly drier (arid) over a long period of time.

Climate change and the resulting higher temperatures have caused increased evaporation, lower soil moisture, lower snowpack and lower stream/river flow in the western US. This is aridification. The term drought is no longer apropos.

In Water Woes-I we learned that the Colorado River Compact (1922) allocated 16.5 million acre-feet per year (MAF) of Colorado River water to the Basin States and Mexico but recent studies show that today there is really only 12.4 MAF available. This 4.0 MAF shortfall is proof that aridification is happening.

Since we are in a state of aridification, and 30% of Marana's Designated Assured Water Supply (DAWS) comes from the Colorado River---how can Marana be approving new housing with water demands well beyond its DAWS? See TA Alert! More Rooftops & Water.

Water is the sustenance of life. Marana leaders need to use common sense and take steps now to protect our precious water resources.

The following articles and podcasts provide some excellent background on aridification and the status of the Colorado River watershed.


Climate Change and The Aridification of North America, Jonathan Overpeck & Brad Udall, 5/19/20

This Article describes the process of aridification and the impact of climate change on that process in the Southwest and other areas of the US. You may recognize the last name Udall. Brad Udall is a scientist at Colorado State University and is the son of Mo Udall who was a US Congressman from Arizona for 30 years. His entire family has been prominent in government and water issues in the West.


America's West Faces A Megadrought. What's The Solution?

This is an On Point (NPR) podcast with host Meghna Chakrabarti. She interviews Brad Udall and the owners of Mountain Island Ranch (Utah/Colorado). They discuss aridification and the impact of climate change on ranching in the West. I highly recommend listening to this podcast (50 minutes). Click on the button below to listen,


Colorado River Status

CAP Know Your Water News reports that inflow to Lake Powell in June was 30% of the 30-year average and cumulative runoff for the runoff season (April-July) was 22% of the 30-year average.

The Lower Colorado Water Weekly Report(7/19/21) shows Lake Powell at 33% full and Lake Mead at 35% full!

Although we've had some nice monsoonal rain here in the Tucson region this week, it is really just "a drop in the bucket". The Colorado River situation remains dismal. Remember 36% of Arizona's water supply comes from the Colorado River.


Extreme actions underway to ensure Glen Canyon Dam can continue to generate power, Brian Maffly, Salt Lake Tribune, 7/19/21

The Colorado River not only supplies water for agriculture and municipal use but also provides major hydroelectric power for the western states. A power crisis looms over the West as the reservoir levels continue to drop at Lake Powell (Glen Canyon Dam) and Lake Mead (Hoover Dam). See current status above.

This Article discuss recent steps taken by the US Bureau of Reclamation (USBR) to release water from Flaming Gorge Reservoir to Lake Powell to ensure hydroelectric power generation can continue at Glen Canyon Dam. Thanks to TA Member Joe Thomas for providing this article.

Glen Canyon Dam Hydroelectric Unit has a capacity of 1.320 megawatts and supplies power to several western states.

Hoover Dam Hydroelectric Unit has a capacity of 2,080 megawatts and supplies power to California and several Indian Tribes.


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