CLARIFICATION: This story was updated to clarify the effect on Lake Mead if more water is held back in Lake Powell.
LAS VEGAS (KLAS) — An unprecedented proposal to keep more water in Lake Powell to ensure power production at Glen Canyon Dam could send the water level at Lake Mead seven to eight feet lower than initial projections, according to an official with the Southern Nevada Water Authority (SNWA).
Colby Pellegrino, SNWA deputy general manager, said the proposal would not drop Lake Mead levels below current requirements to meet water usage commitments.
But it comes as Lake Mead drops below 1,060 feet for the first time ever. The lake level is expressed in relation to sea level — not depth. The surface of the lake is currently 1,059.1 feet above sea level. It’s the lowest it’s been since 1937, when the lake was still filling.
The proposal to keep an additional 480,000 acre feet of water in Lake Powell — water that is normally released downriver to go to Lake Mead — would result in lower levels for Lake Mead. Allowing the normal flow of water downriver would keep Lake Mead levels higher and ensure confidence in water supplies. Most of the water released from Lake Mead is used by California.
The decision on whether to keep the water in Lake Powell is expected by April 22.
The urgency is twofold: Glen Canyon Dam produces power for customers in five states, and if power production infrastructure is damaged by low water levels, it could cause problems with future water releases, according to Assistant Interior Secretary Tanya Trujillo. She spoke to the Arizona Daily Star in Tucson, Arizona.
Hoover Dam can produce power when the level at Lake Mead is as low as 925-950 feet, Pellegrino said.
Seven states that belong to the Colorado River Basin will talk about the proposal and how to spread it out for “water year” 2022, which runs from October 2021 through September 2022.
When the federal government declared a water shortage last summer, it invoked Tier 1 cuts in water usage. Water conservation initiatives have kept supplies available through a 20-year-long drought — now sometimes described as a “megadrought.” Pellegrino emphasized the need for continued adherence to conservation measures.
If Lake Mead’s water level drops below 1,050 feet, Tier 2 cuts would kick in for Arizona, California, Nevada and Mexico.