Vegas Gamble: Lake Mead plunges to record low

They're rolling the dice again in Vegas. This time the bet is on how long water supplies from Lake Mead will last.

Lake Mead is at an all time record low this month; the lowest level since the Hoover Dam was dedicated creating Lake Mead 75 years ago.

Lake Mead water level. (Click to enlarge)

I had the opportunity to see the stunningly beautiful and amazingly engineered Hoover Dam first hand on Monday. I also saw the beached white bathtub ring on the canyon walls above Lake Mead that shows how precipitously the lake level has plunged in the past 12 years.

Lake Mead on Monday. Note the bleached rocks showing high water of the past, and how far the lake has dropped exposing the Hoover Dam intake straws.

(Photos by Paul Huttner. Click to enlarge)

Lake Mead is a major reservoir on the Colorado River just east of Las Vegas. Vegas draws 90% of its water supply from Lake Mead. This week Lake Mead fell to just 39% of capacity and stands at 1083.55 feet above sea level. That is the lowest level since the lake was created in the 1930s. Lake Mead was nearly full just 12 years ago in 1998.

Why the plunge in water levels?

Call it the perfect storm for water supplies in the southwest.

Lake Mead is one of several reservoirs along the Colorado River system in the southwest. The usually mighty Colorado River supplies precious water and hydroelectric power to Las Vegas, Phoenix, Tucson, Los Angeles and San Diego. Explosive population growth in the southwest over the past 50 years has largely been made possible by river water from the Colorado.

Hoover Dam spillway and hydroelectric power plant below the Dam. The new bridge arches gracefully over the canyon.

It also provides extensive water for agriculture in southern California. That salad you ate last week quite possibly grew on Colorado River water.

Back in the 1920s and '30s when water managers estimated supplies form the Colorado they used average flow rates from one of the wetter decades on record. They estimated the Colorado would produce 17.1 million acre feet annually, and they allotted cities and farms accordingly. Reality has been closer to 14 million acre feet per year.

Much lower than anticipated flows have left most of the Hoover Dam intakes exposed.

After the huge El Nino event of 1997-'98 dumped flooding rains and copious amounts of snow on the southern Rockies, Lake Mead brimmed at nearly 100% capacity. Since then, 12 years of drought in the southwest has drained the lake to its current 39% level.

These stunning NASA images show how the decline in water levels has made entire sections of Lake Mead dissapear over the last 25 years.

Lake Mead August 1985 (NASA Landsat 5 image. Click to enlarge)

Lake Mead August 2010 (NASA)

Dr. Ken Dewey at the University of Nebraska-Lincoln is an expert on all things Colorado River. I have interviewed him on Jet Streaming in the past, and he has a wealth of information on Lake Mead here.

Could Lake Mead run dry?

This summer's transition to La Nina in the Pacific Ocean is not good news for water resources on the Colorado. La Nina winters tend to run warm and dry in the desert southwest. Snow pack usually runs below average in the Colorado basin.

The trend of warmer spring temperatures at high elevation tends to cause greater evaporation of snow pack in the Rockies before it can melt and runoff into the Colorado River watershed where it can turn into liquid gold in the reservoir system.

Some researchers have run models that estimate Lake Mead has a 50% chance of going dry by 2021! If it happens, that's just 11 years for water managers to scramble to find alternative ways to bring water to thirsty Las Vegas.

Your intrepid weather reporter atop the Hoover Dam Monday.

(Photo by Eric James Miller)

There are other options, like releasing more water from Lake Powell upstream. Right now water managers in Las Vegas are scrambling to build another "straw" into Lake Mead online to feed water to Vegas because the Lake level has dropped below current intake pipes.

The view of Lake Mead from Boulder City, Nevada. Note new islands expanding as the water level drops.

The southwest has been in what some researchers call a "mega drought" for the past 12 years. If the drought continues another decade, southwestern cities like Las Vegas are going to face some very difficult and costly decisions about where to draw water for thirsty residents and farms. Right now Las Vegas is paying homeowners $1 per square foot to convert water draining lawn space to native desert landscape. (xeriscape)

Moblie weather lab view of Lake Mead flying out of Vegas Tuesday.

We've had our share of (in some cases record) floods in Minnesota this year. While floods cause major short term problems for those in the path, we can be thankful for the abundance of water they provide.

I witnessed first hand this week what the slice of life looks like in a place where water is scarce and dwindling. It made me more thankful than ever to live in a state where fresh clean water is all around us.

It really makes you appreciate the land of 10,000 lakes.

PH