Expect Las Vegas water shortage to remain in effect as Lake Mead projections come out

LAS VEGAS ( KLAS ) — Water shortage levels for Southern Nevada are not expected to change when the federal government makes its anticipated once-a-year announcement this week.

The decision is made each year in mid-August, based on projections for Lake Mead’s level in the coming year. Lake Mead is the nation’s largest reservoir. It’s currently only a third full.

But for Las Vegas, that’s only half the story. Conservation measures and water recycling have allowed Las Vegas to reduce water use while the city has added residents. The Southern Nevada Water Association (SNWA) continues to promote conservation to reduce outdoor water use.

So far this year, Nevada has recycled about 150,000 acre-feet of water, returning treated wastewater to Lake Mead via the Las Vegas Wash. An acre-foot is 325,851 gallons — literally, the amount needed to cover an acre with a foot of water. That’s enough to supply two to three households for a year.

Recycling effectively cuts the amount of water used because SNWA gets credit for the water returned to Lake Mead. About 85% of all water used indoors is reused. But none of the water used outside is recycled. That accounts for about 60% of the total amount of water that we use.

During hot summer months, the amount of water lost to outdoor use rises as sprinklers run six days a week. Figures in the table above show that 79% of the water used in February was recycled while only 41% was recycled in July.

So far this year, SNWA has received credit for 54% of the water that’s been taken out of Lake Mead thanks to recycling efforts. That number will increase as it cools down and less water is used outdoors in November and December.

Lake Mead is currently at 1,061.75 feet (the elevation of the lake’s surface) and is expected to be about 2½ feet deeper in January, about 1,064.30 according to forecasts released in July.

On Aug. 7, the lake began to rise. Levels upstream in Lake Powell began to fall on July 10. The charts below show Lake Mead on the left and Lake Powell on the right:

The difference in Lake Mead’s level is only a few inches.

The Las Vegas valley and all of the desert Southwest is currently under Tier 1 water restrictions, which began in January 2022 . More than 40 million people rely on the river for water.

Here’s how it works: In August, the U.S. Bureau of Reclamation looks ahead at next year’s projections for Lake Mead and then sets the water restrictions, which begin the following January.

As long as the level remains below 1,075 feet, restrictions will continue. And 1,075 is not in the projections for the next two years, even though the lake briefly got there earlier this year . Projections show a range of possibilities, but the “most probable” levels at Lake Mead fall in the Tier 1 range: above 1,050 feet and below 1,075 feet.

And the most probable five-year outlook indicates more of the same:

If the projection is true, Southern Nevada will remain under Tier 1 restrictions through 2029.

If anything, the five-year projection is optimistic, with the most probable line showing a stable Lake Mead. That’s contrary to recent history, when wild swings plunged the lake to a new low followed by a dramatic recovery. The projections are simply probabilities based on the best climate models available. The projection is no guarantee the lake level will stay where it is five years from now. Roll the dice 100 times and the most-probable result is the average of all the rolls. That doesn’t mean you won’t see snake eyes — maybe even next year.

This year’s winter was slightly above normal, with snowpack reaching 111% in April. But the scorching temperatures in Las Vegas are a reminder of what scientists say is ahead for the Colorado River. The area is heating up, with an average temperature that has increased more than 2 degrees since the “megadrought” began in 2000. Lake Mead has dropped more than 150 feet during the drought.

La Niña conditions expected this year will mean continued dry conditions for the Southwest.

Conservation efforts have been effective — but have they come too late? Kyle Roerink of the Great Basin Water Network believes so.

Roerink is looking past the benefits of the past two winters, at projections 10 and 20 years out. He says Nevada is pretending it’s not the most arid state in the U.S., and growth just can’t continue. Conservationists are waiting to hear what the government has to say this week.

Elected officials have trumpeted projects paid for by President Joe Biden’s Inflation Reduction Act to increase the efficiency of water delivery. Billions have been spent on agreements with tribes and water agencies to reduce water use, which will help to prop up lake levels at Lake Mead and Lake Powell.

Calculating exactly how the federal spending translates to a more stable Lake Mead is difficult because there are so many moving pieces, and the time frames vary on many of the agreements.

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