3:47 p.m. ET, August 16, 2022
Why the actual water level in Lake Mead doesn't match up with what was announced today
From Angela Fritz, CNN Senior Climate Editor
We should address the elephant in the room: There is actually less water in Lake Mead than what the US Bureau of Reclamation reported on Tuesday.
And, significantly, it was enough to prevent Southern California from having to take its first mandatory cut of Colorado River water.
So what’s happening?
Earlier this year, the bureau
announced an emergency plan to keep Lake Powell from plummeting so low that Glen Canyon Dam wouldn’t be able to generate hydropower. It is releasing more water from upstream reservoirs, and it’s also withholding water in Lake Powell, rather than sending it downstream to Lake Mead and the Lower Colorado River Basin.
Lake Powell was supposed to release 7.48 million acre-feet of water to Lake Mead this year. Instead, it only released 7 million, leaving 480,000 in Powell.
Tuesday’s report took that into account. It lays out the numbers as if that water was delivered to Lake Mead.
Of course, all of this water is still in the same Colorado River system. Lake Powell and Lake Mead are like massive buckets that manage the rate of flow through the river and ensure everyone along it has the water they need.
Patti Aaron, a spokesperson for the bureau, previously explained it to CNN this way:
“If ‘actual elevation’ projected January 1 elevations are used in August, it would almost certainly put the Lower Basin in Tier 2 in 2023,” Aaron said. “To keep the water accounting ‘operationally neutral’ and not penalize the Lower Basin for leaving the water to benefit Lake Powell, we will run the models as if the [480,000 acre-feet] had been delivered to Lake Mead.”
Notably, running the math this way wasn’t enough to prevent the Lower Basin from falling into a Tier 2 shortage — but it was enough to prevent California from having to make cuts.
The real “physical elevation” of Lake Mead is expected to be around 1,041 feet come January. The projection after adding the withheld water was 1,047.
And California doesn’t experience a Colorado River water cut until Mead is projected to drop to 1,045 feet.