Newly discovered damage to part of the dam holding back America's second-largest reservoir has people who rely on the Colorado River worried about their ability to get the water they need.

Plumbing issues at Glen Canyon Dam, which holds back the second-largest reservoir in the U.S., are causing concerns about future water delivery to southwestern states.

A set of Glen Canyon Dam pipes that were eroding from the inside have been recoated — two months early and under budget, according to the U.S. Bureau of Reclamation.

As Gus Levy traipses across the 710-foot-tall Glen Canyon Dam, there's a bounce in his step as he details the complicated workings of this structure built in 1960.

To critics, Glen Canyon Dam was one of the U.S.'s biggest environmental mistakes. But it generates electricity for about 5 million people in seven states.

Damage to Glen Canyon Dam reveals vulnerabilities of the entire Colorado River system Recently discovered issues could affect how Upper Basin states deliver water to Lower Basin states.

“This solution would solve Glen Canyon Dam’s water delivery problem, and could also afford the Bureau maximum operational flexibility at Lake Powell,” the report says.

Newly discovered damage in Glen Canyon Dam would require releasing less water at low reservoir levels — a problem that increases water risks in the Southwest.

But Lake Powell would still stretch 100 miles into Glen Canyon at dead pool. That’s because there is a significant design flaw in the dam: There is no drain at the bottom.

"That would allow operation of the dam from dead pool all the way down to river level, allowing for full operational flexibility of Glen Canyon Dam at every level,” Balken said.