Friday May 13, 2022
The Conversation —
Journalists reporting on the status and future of the Colorado River are increasingly using the phrase “dead pool.” It sounds ominous. And it is.
Dead pool occurs when water in a reservoir drops so low that it can’t flow downstream from the dam. The biggest concerns are Lake Powell, behind Glen Canyon Dam on the Utah-Arizona border, and Lake Mead, behind Boulder Canyon Dam on the Nevada-Arizona border. These two reservoirs, the largest in the U.S., provide water for drinking and irrigation and hydroelectricity to millions of people in Nevada, Arizona and California.
Some media reports incorrectly define dead pool as the point at which a dam no longer has enough water to generate hydroelectricity. The more accurate term for that situation is the minimum power pool elevation.
As a 22-year drought in the Colorado River basin lingers, reaching minimum power pool elevation is the first problem. Lakes Powell and Mead have turbines at the bases of their dams, well below the surface of the reservoirs. Water flows through valves in intake towers in the reservoirs and is channeled through the turbines, making them spin to generate electricity.