Lake Mead and Southwest
WGN Chief Meteorologist Tom Skilling hosts a special series, “Forecast – A Fragile Climate.” In his 50 years as a meteorologist, he has seen the atmosphere do things he never thought possible. This led him and the WGN team to travel across the country in search of the latest climate research and information. Serious work is underway – from tracking the Earth’s vital signs to large-scale climate adaptation projects.
At 1 p.mSkilling visits his beloved Alaska, an area changing three times faster than other parts of the world.
At 2 p.mwe’ve taken you to the epicenter of earth science, where the power of the human brain and sophisticated hardware intersect in the study of our changing planet.
In the final stretch, Skilling and the team head to the drought-stricken Southwest. The country’s driest metropolitan city is powered by the country’s largest reservoir and is in dire straits. But this is a story of innovation and how one community went to great lengths to adapt to a changing climate.
Lake Mead is 40 miles from Las Vegas.
Capt. Ray Pullen guides visitors in hopes of snagging a striped bass from the basin. He has fished the waters of Lake Mead for 27 years. In the last five, his business has almost stopped. It is not easy to get out on the water. Only one launch point remains, and it’s a dusty outbuilding where water once stood.
“This drought has been going on for 20 years,” he said.
Among the harsh beauty is an ugly reminder. What is called the “bathtub line” marks where the water table once reached. Since 2000, the reservoir has dropped about 170 feet.
“No one has seen this since the dam was built,” Poulin said. “It’s never been this low since they filled it up.”
It was back in the 1930s when the pool overflowed from the Colorado River. Hoover Dam was built for power, flood control, recreation, and water storage.
“It’s unbelievable,” Poulin said. “I moved here in 1996 from the great state of Maine and saw the water flowing over the dam, over the spillway, until maybe 2011. And now to watch her drop 170-plus feet is depressing.”
As demand grows beyond what the river can produce, Colorado River flows have dropped 20% from last century’s average. The last 22 years have been the driest on record in the river basin. Climate change is warming the region and has contributed to a sharp reduction in the amount of rain and snow in winter. The region is experiencing a drought that is believed to be the worst in 1,200 years. Nevertheless, 40 million people rely on natural resources. More than two million of them live in growing Las Vegas.
Ninety percent of the district’s water supply is pumped from the reservoir. But one intake is now exposed and no longer functional due to historically low water levels.
A few miles away in downtown Las Vegas, Deputy General Manager for Resources Colby Pellegrino makes it clear, “The future here is in water conservation.”
Pellegrino says the Southern Nevada Water Authority recognized the dire situation two decades ago when drought conditions forced their hand.
“What we are seeing may not be a temporary drought. It could be a permanent ecosystem, an environmental change where we will continue to get less rainfall, higher temperatures; and it will fundamentally change our basin and hydrology,” Pellegrino said. “We are seeing elevations that have never been seen in these reservoirs. And we know that climate change will continue to affect them.”
Rather than risk the rate rising naturally, the agency took drastic action.
“Climate change has affected us in many ways,” she said. “Heating temperature is key. We are seeing more days with temperatures above 100 degrees. We expect this to continue to grow. We’re thinking about mid-century, we’ll add about 30 more days above 100 degrees to what we have today. All this warming leads to more water use.’
To adapt, they dug deeper.
“The largest climate change adaptation project we’ve undertaken is the construction of our third intake and low-lake pumping station,” Pellegrino said. “Climate change will require adaptation, and this is one of the largest adaptation projects in the world. That’s 34 pumps penetrating Lake Mead deeper than ever before to continue supplying water to Las Vegas. This project cost 1.2 billion dollars. This is the largest amount spent on a climate adaptation project by any single city in the world.”
The system, called the “Third Straw,” completed in 2020, draws water from Lake Mead even when the level drops to the so-called “dead pool” — then water can no longer flow through Hoover Dam downstream to users in California, Arizona and Mexico.
“Our water supply does not go anywhere. “The Colorado River is basically snowmelt in the Rocky Mountains,” Pellegrino said. “So the biggest manifestation of climate change is how it changes the flow of the Colorado River. And that’s why we’re working hard to make the river a slightly more sustainable future. … We are a fairly new town. So when it goes down the drain, it’s captured and put back into the Colorado River through Lake Mead.”
The bigger problem is outside and the “incredibly dry environment”.
“Nothing grows outdoors without irrigation,” Pellegrino said.
Incentives and water-restriction programs have worked to reduce consumption, even as the region’s population grows rapidly.
“Since 2002, we’ve added about 750,000 people to this valley. We also use 26% less water,” said Pellegrino.
With the exception of schools, parks and cemeteries, the natural desert landscape is preferred – in some cases mandatory – to high-maintenance lawns.
“Money for weed,” Pellegrino said. “We pay $3 a square foot to have you remove and replace your grass.”
Golf courses have a water budget, just like casinos. These fancy fountains at Bellagio are nasty ground water pumped to great heights for entertainment, not to drain the system.
“We have no problems with growth. We have a water footprint problem,” Pellegrino said.
Even with the aggressive efforts, there is another problem: the tall structures surrounding Hoover Dam take water to generate power.
Forecast – Climate Series:
Part 1: What Alaska’s Glaciers Tell Us About Warming
Part 2: NASA’s thoughts and technology track the planet’s changes
Noe Santos knows water. He grew up in the area. The manager of river operations for the U.S. Department of the Interior says that current supplies do not match past allocations.
“What we didn’t know then, but we know now, is that the early 1900s was one of the wettest periods on record for the Colorado River,” he said.
Santos said things are different now, in drier times.
“On a good year, we lose about five feet of elevation with all the different uses and inflows,” he said. “We’re going to lose about 14 feet or so in height this year.”
At Hoover Dam, water creates power for 450,000 households. About 50% goes to California, with Nevada and Arizona sharing the other half.
“The next chapter in the history of the Colorado River is going to be uneventful,” Pellegrino said. “Everyone should use less.”
https://wgntv.com/weather/forecast-a-fragile-climate/forecast-a-fragile-climate-lowering-water-levels-spell-deep-trouble-for-drought-plagued-southwest/