A long-standing drought in the American Southwest is getting worse by the day, threatening reservoirs and groundwater supplies.
And the first sign of “serious damage” could be a whirlpool, according to the operators of the nation’s second-largest reservoir, Lake Powell, reports the Washington Post.
Lake Powell is already a quarter of its size and a drop in the water level of another 38 feet down the concrete face of the 710-foot Glenn Canyon Dam would put the surface of the reservoir close to the tops of eight underwater openings that allow river water to pass through the hydroelectric dam.
Lake Powell could suddenly transform into something resembling a funnel, with water circling the openings, the dam’s operators say. Should this happen, the massive turbines would have to be shut down because of the risk of destruction by air bubbles.
The only outlet for Colorado River water from the dam would then be a set of smaller, deeper, and rarely used bypass tubes with a far more limited ability to pass water downstream to the Grand Canyon.
Such an outcome – known as a “minimum power pool” – was once unfathomable here. Now, the federal Bureau of Reclamation projects that day could come as soon as July.
Things could get worse, leading to an even more catastrophic event. The water level could fall all the way to the lowest holes, so only small amounts could pass through the dam. Such a scenario — called “dead pool” — would transform Glen Canyon Dam into a hulking concrete plug corking the Colorado River.
A “lifeline of the Southwest”
The Colorado River has long been known as the “lifeline of the Southwest.” The river supplies water to 40 million people in seven states, 29 Native American tribes, and parts of Mexico. Farmers use it to irrigate nearly 5.5 million acres of agricultural land.
The 1,450-mile-long river begins in the Rocky Mountains of Colorado. It passes through Lake Powell, the Grand Canyon, and Lake Mead before ending in Mexico’s Sonoran Desert. Altogether, its drainage basin spans about 246,000 square miles, representing 8 percent of the land in the continental United States, and fuels a $1.4 trillion annual economy.
Back in August, the Bureau of Reclamation announced it would support studies to find out if physical modifications could be made to Glen Canyon Dam to allow water to be released below critical elevations, including dead pool.
The announcement implies they are studying such costly and time-consuming construction projects as drilling tunnels through the Navajo sandstone at river level, said Jack Schmidt, a Colorado River expert at Utah State University.
“There was a time in my professional career that if anybody from Reclamation ever said that, they’d be fired on the spot,” said Schmidt, who served as the chief of the U.S. Geological Survey’s Grand Canyon Monitoring and Research Center during the Obama administration.
Schmidt added, even raising that issue is“a huge sea change telling you how different the world is.”
