Glen Canyon Dam - Long-Term Cavitation Damage To Key Water Release System Revealed
EDIT
Conservation groups are calling for changes to the management of Lake Powell, the nation’s second largest reservoir, after the discovery of damaged plumbing within the dam that holds it back. The damage is to Glen Canyon Dam’s “river outlet works,” a critical set of small tubes near the bottom of the dam that were originally intended to release excess water when the reservoir is nearing full capacity. The reservoir is currently only 32% full, beleaguered by climate change and steady demand. Water experts think the river outlet works may soon become the only way to pass water from Lake Powell, situated in far northern Arizona, to the Colorado River on the other side. Experts worry that damage to those tubes could impede the ability to use them regularly.
It’s the latest twist in the saga of Glen Canyon Dam, which has been at the center of recent concern about the shrinking Colorado River, even before news of the damaged pipes came to light. Water experts fear Lake Powell could drop so low that water would be unable to pass through hydropower turbines that generate electricity for about 5 million people across seven states. If it falls even lower, water would be unable to pass through the dam at all, keeping it out of the Grand Canyon just downstream of Lake Powell.
EDIT
The recent damage to the outlet works is the product of a process called “cavitation.” It happens when small air bubbles in the water pop while passing through the dam’s plumbing. That implosion is strong enough to create shock waves that tear away small chunks of protective coating on the insides of pipes. In recent years, the outlet works has been used to release temporary bursts of water designed to boost ecosystems in the Grand Canyon. The cavitation damage was discovered during inspections of the pipes after a series of those planned water bursts in April 2023.
In an informational webinar on Monday, Reclamation officials explained the damage and said it was not the result of one specific event, but has occurred over time. Nick Williams, Upper Colorado River power manager for the Bureau of Reclamation said cavitation damage is more likely when reservoir levels are low. The river outlet works can still carry water, but will require repairs – such as a fresh coating of epoxy that is scheduled for either later this year or early 2025. Even with a fully functioning river outlet works system, those pipes are only capable of carrying a relatively small amount of water. If the outlet works become the only means of passing water through the dam, the Colorado River’s Upper Basin states – Colorado, Wyoming, New Mexico, and Utah – could fail to meet a longstanding legal obligation to pass a certain amount of water to their downstream neighbors each year.
EDIT
https://www.kunc.org/news/2024-04-12/a-plumbing-issue-at-this-lake-powell-dam-could-cause-big-trouble-for-western-water
= new reply since forum marked as read
Okay, for the sake of documentation I suppose. I don't do math yet it all makes sense to me. 
