Colorado River watershed

The Drying of the West

Revisit the Colorado River

As you hopefully remember from class, the Colorado River starts in north central Colorado, but has tributaries even further north, so that the watershed encompasses parts of seven states. The flow of the river was wildly overallocated so that even in normal times the total of the allotments (16.5 million acre-feet) is greater than the entire flow of the river (which was averaging 16.3 million acre-feet). And these are not normal times. The prolonged drought means that there has been a long term steady decline.

Originally I had planned to try and due a full update about the Colorado, but there is simply too much going on – water levels are dropping and are projected to continue to drop for the next five years (and beyond that too), shortage measures are being applied in areas all over the watershed and there are bodies, WWII landing craft and ghost towns are being exposed in Lake Mead. The best I can do for you here is remind you of the links to the water level data we used in class. If you are interested in following the water levels in Lake Mead and Lake Powell, I recommend these sites:

An x-y line graph of water levels in Lake Mead from when the dam was first complete to mid-July 2022. The graph has horizontal lines showing important benchmarks.
Lake Mead Water Levels graph from Arachnoid.com from July 18, 2022. You can see that water levels have dropped below the line indicating Shortage Condition II. The water level hasn’t been this low since the dam first began filling in the late 1930s.
  • You can see another interesting way of exploring the data at the Lake Online website (https://mead.uslakes.info/Level/), where data from the last few years is compared.
Line graphs showing the water level in Lake Mead for 2020, 2021 and 2022.
LakeLevels allows you to compare the lake levels for the past 6 (six) years (you can add years by clicking on the boxes under the graph on the website)
Lake Powell water levels 2020, 2021 and 2022 from Lake Levels website.
As you can see in the LakeLevels graph for July 18, 2022, Lake Powell received its annual Spring runoff boost in May/June (as well as extra water from a reservoir upstream) but even with that water, the level in the lake is incredibly low – lower than it has been since it was filling in the late 60s. Lake Powell is currently still above the Power Generation Limit level of 3490 feet for the Glen Canyon Dam, but the lower the water level gets, the generators become less efficient and less efficient. They are currently operating at about 60 percent of capacity. If the level drops to 3490 feet (or so) it will stop generating power entirely, endangering the power supply for some 5 million people across seven western states. The power won’t suddenly switch off for all of these people, but much more strain will be placed on the grid resulting in more rolling blackouts, brownouts and higher prices for electricity.

This is why in May 3, 2022, the Bureau of Reclamation announced two emergency measures. First, that under a Drought Contingency Plan adopted in 2019, approximately 500 thousand acre-feet (kaf) of water will be released from Flaming Gorge Reservoir from May 2022 through April 2023. Flaming Gorge Reservoir is the largest reservoir in Wyoming (though it actually laps the boarder into Utah) and is located on the Green River approximately 455 river miles upstream of Lake Powell. Second, that another 480 kaf will be left in Lake Powell by reducing Glen Canyon Dam’s annual release volume from 7.48 maf to 7.0 maf, as outlined in the 2007 Interim Guidelines that control operations of Glen Canyon Dam and Hoover Dam.

And if you are wondering why we are worried about the Colorado River, other than empathy and sympathy for fellow humans and the regional ecosystems, remember – Colorado River water is used to grow about 25% of the nations crops, including about 90% of our winter vegetables. Less water means higher food prices and lower availability for all of us.