Why are Lake Powell and Lake Mead dropping so fast?

Recently the Bureau of Reclamation has placed an additional requirement on the 7 states that make up the Upper and Lower Colorado River Group.  They must come up with an additional 2-4 million acre-feet of water by August 2022 or else the Bureau will take things into its own hands.

But what is driving this?

For starters, the climate is hotter in the upper and lower basin states due to climate change.  This dries out the ground under the snowpack, so that when it melts, it is absorbed quicker.  This leaves less runoff. There is even some sublimation going on, that is, a sold, snow, turning immediately into gas, or water vapor, which does not add to the runoff.  Since the runoff into Lake Powell is the main supplier of water to that Lake, the lake receives less runoff now than it did before.  In fact, this year, the runoff is about 51% of last year’s runoff.

Secondly, when the air temperature is hotter, as it has been recently, the rate of evaporation is higher, again leaving less water in the lakes.

Thirdly, consider the shape of lake Powell.  The reservoir from the side has a “v” – type shape, with less water available the further down the level sinks.  This has also caused an increase in the downdraw from the reservoirs.

And fourthly, as Lake Powell shrinks, the powers that be have chosen to focus on keeping the water level high enough in Lake Powell to continue to supply electricity to the Southwest.  This has left even less water for Lake Mead.

All of this has led to an accelerating loss of water level in Lake Powell and Lake Mead. Some experts predict that Arizona will be in a Tier 2a and Tier 2b status as early as the end of next year.   In Tier 2b even the larger cities in Arizona will be affected.

As I contributed to the online Bureau of Reclamation webinar on 7/16/22, I stated that I don’t believe that Arizona can conserve its way out of this predicament.

We are in year 22 of an unknown length drought, with no end in sight.

The puzzle to me is why none of the powers that be have even seriously considered starting a de-salinization project in the Gulf of Baja.

There have been recent articles in the Arizona Republic by some reporters that have stated that de-sal is at least 10 years away. (see Arizona Republic reporter Allhands) I know that this a fallacy because San Diego’s de-sal plant took only 3-4 years from design to implementation. (see internal link…)

And if you look at the platforms of the candidates for Arizona governor, only Marco Lopez and Karrin Robson have uttered the ”de-sal” word.  The longer we wait while embracing the fantasy that “ the rain will come”, the longer we will have before we secure for ourselves a sustainable supply of water.(author)