Critical water reservoirs in West at all-time low

The drought at Lake Mead is so severe the original water intake valve is now visible

As the West grapples with an ongoing climate change-fueled megadrought, Lake Mead— the largest water reservoir in the U.S., which supplies water to 25 million people— has sunk to alarmingly low water levels.

According to a Twitter post from the Southern Nevada Water Authority, for the first time, the lake’s original water intake valve is now exposed. The valve in question has been in service since 1971 and, thanks to the drought, can no longer draw water.

Lake Mead is a human-made reservoir, formed by the Hoover Dam on the Colorado River along the border of Nevada and Arizona, and is the main water source for Las Vegas, 30 miles away. The Colorado River, which provides water to seven western states, has been in crisis due to drought and dropping water levels for several years. Last summer, the federal government declared an official water shortage on the river for the first time, meaning emergency measures must now be taken to restrict water use and prop up lake levels.

The reservoir has three valves; one that can intake water at 1050 feet above sea level (that’s the one that’s no longer working now), one that can intake water at 1000 feet above sea level, and the third and final valve— which was constructed by the Southern Nevada Water Authority seven years ago in response to the drought— that can intake water at 900 feet above sea level.

On Monday, the Southern Nevada Water Authority turned on the third valve and a new $650-million low lake pumping station, which was completed in 2020.

Currently, Lake Mead is about 30 percent full. As of Thursday, the reservoir’s elevation sat at about 1,056 feet above sea level.

If this crisis continues to worsen and the second valve also becomes inoperable, this third valve only has the ability to supply water to Nevada. If the lake dips below an elevation of 900 feet, Hoover Dam will no longer be able to release water downstream from the Colorado River to California, Arizona, and Mexico. That’s obviously bad news. In Arizona, for example, the Colorado River is the state’s main source of water — including the roughly five million people in the cities of Phoenix and Tucson. Farms in Arizona have already been cut off earlier this spring, causing thousands of acres of alfalfa and cotton to go dry.

This week, 6 million residents in Southern California will also be required to cut down on water usage. In an unprecedented move, the Metropolitan Water District of Southern California ordered a restriction— limiting outdoor watering to one day a week.

“Metropolitan has never before employed this type of restriction on outdoor water use. But we are facing unprecedented reductions in our Northern California supplies, and we have to respond with unprecedented measures. We’re adapting to climate change in real time,” Metropolitan General Manager Adel Hagekhalil said in a press release.

According to the Metropolitan Water District of Southern California, 25 percent of Southern California receives its water from the Colorado River Aqueduct. However, the state as a whole gets the majority of its water from snowpack in the Sierra Nevadas. The outlook for snowpack is also pretty bleak due to the drought. As the summer snowmelt season kicks into full gear, snowpack levels are already critically low — the lowest in the past seven years.

Upstream from Lake Mead, Lake Powell — the second-largest reservoir on the Colorado River — is also running dry. Levels at Lake Powell reached a new record low earlier this year since the reservoir built on the Utah/Arizona border was first filled in 1980. Without drastic measures — like siphoning water from other reservoirs in Utah — Lake Powell is expected to drop low enough to prevent operation of the massive hydropower turbines that supply electricity for more than three million people across the region.

Even further upstream in the mountains of Colorado, investment companies are already bidding up the cost of water rights that farmers and other landowners hold — in a dystopian sign of gearing up for drier days ahead.

Unfortunately, there is no natural end in sight for the western mega-drought, North America’s driest dry spell in 1,200 years. The region is experiencing the driest 22-year period in knowable history, according to a study published in Nature earlier this year. The same scientists say that around 40 percent of the severity of the drought can be attributed to human-caused climate change.

This drought is also unique in recorded climate history because it is not driven primarily by precipitation deficits, but by exceedingly high temperatures, which cause faster evaporation rates.

Rapid drying over the past two decades across the West has also increased the risk of wildfires, insect damage to trees, a decline of snowpack, and brought heat waves that would have been “virtually impossible” without the burning of fossil fuels and other causes of climate change.

A drought caused primarily by climate change will not go away by hoping for a few good rainy seasons. It can go away only through large-scale climate action.