Las Vegas Sun

March 29, 2024

Drought:

Deliveries to be cut as Lake Powell approaches crisis level

Lake Powell Pipeline

AP

This Aug. 21, 2019, image shows Glen Canyon Dam at Lake Powell in Page, Arizona.

Updated Wednesday, April 27, 2022 | 5:23 p.m.

Lake Mead Bathtub Ring

A view of intake towers at Hoover Dam Saturday, July 13, 2019. The white stripe on the rocks is the Lake Mead Launch slideshow »

Lake Mead’s “bathtub ring” is set to become even more pronounced this year.

The lingering drought is the overriding reason that the lake’s water level will fall again in 2022, but it’s also because less water will be released upstream on the Colorado River from Lake Powell.

This month, the seven Colorado River Basin States — Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming — agreed with federal officials’ recommendations to institute a 480,000 acre-foot reduction from Glen Canyon Dam on Lake Powell to reduce the risk of the lake declining below 3,490 feet.

The Department of Interior sent a letter April 8 to the seven Colorado River Basin states making the suggestion, stating that “it is our collective judgment that additional cooperative actions should be taken this spring to reduce the risk of Lake Powell declining below critical elevations.”

The basin states, in a response letter, expressed concern that the water level of Lake Powell would decline below critical elevations, making the dam inoperable. With low-runoff conditions and record droughts over the past two decades, water storage in the Colorado River reservoirs is at a historic low, the states’ letter says.

Lake Powell is at 25% capacity, and Lake Mead is around 35% capacity. The basin states are concerned that the water level of Lake Powell will decline below critical elevations, which would require any further releases to be made through massive outlet tubes at the foot of the dam.

Glen Canyon Dam was not envisioned to operate solely through the outlet works for an extended period of time, Tanya Trujillo, the assistant secretary of the interior, wrote in the letter. Operating at this low lake level “increases risks to water delivery and potential adverse impacts to downstream resources and infrastructure,” she wrote.

Those adverse impacts include generating electricity for parts of the Western U.S. and providing drinking water for the city of Page, Ariz., and the LeChee Chapter of the Navajo nation, Trujillo wrote.

Water released from Lake Powell flows down the Colorado River and into Lake Mead, where it is stored and used by Nevada, California, Arizona and Mexico. Releasing less water from Lake Powell has the potential to reduce Lake Mead by about another seven feet in elevation, said Bronson Mack, public information officer with the Southern Nevada Water Authority.

Taylor Hawes, the Colorado River program director for the Nature Conservancy, said the reduction in water release was a reflection of the unprecedented nature of conditions in the Colorado River Basin. The Upper Basin states also recommended releasing 500,000 acre-feet of water from Flaming Gorge reservoir in Wyoming to protect Lake Powell.

“We are in uncharted territory,” Hawes said in an email. “These dire conditions affect everyone in this region — whether a city dweller who gets drinking water from the Colorado River system, a farmer, rancher, or someone who recreates on or near rivers.”

The proposed changes should be a call to action to change the way parties use and manage the river and its tributaries, Hawes said.

Southern Nevada has been “preparing for this for 20 years,” Mack said, investing in water conservation and water infrastructure.

It invested $1.3 billion in new infrastructure in Lake Mead with its deep-water intake No. 3 pump and a low lake level pumping station. Both give the water authority access to the water supply regardless of Lake Mead’s elevation level, Mack said.

On Wednesday, the Southern Nevada Water Authority will turn on the low lake level pumping station to a full operational status instead of its current testing status, Mack said. The low lake level pumping station is the deepest pumping station, forcing water up from the bottom of the lake and bringing it to its treatment facilities.

The SNWA’s pumping station No. 1 is inoperable, Mack said, since lake levels have dropped to a point where it can no longer pump water. If lake levels continue to drop and its pumping station No. 2 becomes inoperable, the authority can pump from the intake station No. 3 and the low-lake level pumping station.

Meantime, the water authority continues to tout Southern Nevada’s water conservation effort.

“Through our water conservation efforts, we have reduced our demands here locally on Lake Mead,” Mack said, “so we’re taking less water but serving more people than we did two decades ago.”

About 99% of the water used for indoor purposes in Southern Nevada is recycled. Residential water use — from washing machines, dishwashers, showers and toilets — gets collected in the sanitary sewer system, travels to wastewater treatment facilities where it is treated and released safely back into Lake Mead through the Las Vegas Wash.

“Every gallon that we return to Lake Mead allows us to bring another gallon into the valley through the drinking water treatment process without it counting against our allocation (of the Colorado River water),” Mack said. “So our indoor water use is virtually a perpetual motion machine.”

The water Southern Nevada uses outdoors, which accounts for 60% of the total water usage, can’t be recycled, however, so the state and the water authority have taken steps to reduce outdoor water use, from limiting the ability to grow grass, limiting the size of swimming pools and installing drought-resistant plants in landscapes.

While the decision to curtail water releases from Lake Powell is temporary, the Colorado River Basin states are preparing for less water in 2023. The states’ letter says that water releases in 2023 should be “carefully monitored.”

“We’re all reliant on being able to access water out of Lake Mead,” Mack said. “We’re all reliant on the entire Colorado River as a whole. And we have a history of working cooperatively amongst the seven states to address some of the water challenges that are facing the Colorado River.”

CORRECTION: Corrected infrastructure investment dollar figure to "$1.3 billion" instead of "million" | (May 3, 2022)