Water levels at Lake Mead this week have dropped to historic lows, bringing the nation’s largest reservoir within 150ft of the ‘dead pool’ – when the reservoir is so low that water cannot flow downstream of the dam.
On Wednesday, Lake Mead’s water level was measured at 1,044.03 feet, its lowest elevation since the lake was filled in the 1930s. If the reservoir dips below 895 feet — a possibility still years away – Lake Mead would reach a dead pond, with huge consequences for millions of people across Arizona, California, Nevada and parts of Mexico.
“These are extremely serious things,” said Robert Glennon, a professor emeritus at the University of Arizona who specializes in water law and policy.
Persistent drought conditions over the past two decades, exacerbated by climate change and increased water demand in the southwestern United States, have contributed to the depletion of Lake Mead. Although the reservoir is at risk of becoming a dead pool, it would likely take several more years to reach that level, Glennon said.
Meanwhile, the United States Bureau of Reclamation and water managers in the Southwestern United States are working to manage the flow of water in the Colorado River and regulate the use of the water between the states of the region. These measures are designed to help replenish Lake Mead, which was created on the Colorado River on the Arizona-Nevada border when the Hoover Dam was built in the early 1930s, and another badly depleted reservoir, Lake Powell, which was created along the border of Utah and Arizona.
Dead pool wouldn’t mean there was no water left in the reservoir, but even before Lake Mead reached that point, there were fears that water levels could drop so low that hydroelectric power generation would be hindered.
“Power generation in our western reservoirs is becoming a problem as the water level in the reservoirs drops,” Glennon said.
When a reservoir is depleted, there is less water flowing through the turbines and less liquid pressure to spin them, which means the turbines produce less electricity, he added.
Glennon said Lake Mead water levels have unexpectedly seen significant drops in recent years. Around this time last year, Lake Mead’s elevation was measured at around 1,069 feet, according to the Bureau of Reclamation. In 2020, water levels at the end of June were around 1,087 feet.
In late April, falling Lake Mead water levels exposed an intake valve that began supplying Nevada customers in 1971. The following month, two sets of human remains were discovered due to receding shoreline of the tank.
Glennon said the situation at Lake Mead is forcing local officials to take “dramatic steps” to replenish the reservoir, especially as climate change is expected to worsen drought conditions in the West and will continue to affect the amount of water flowing into the Colorado River.
“It’s the 23rd year of drought, and we don’t know if it’s a 23-year drought, a 50-year drought or maybe a 100-year drought,” he said. “We just don’t know what will turn things around.”
Catherine Prociv contributed.