OROVILLE, Calif. (CBS) – After 11 months of investigation, an independent team on Friday released the final report on the Oroville spillway.

A report by the team of six dam experts found the problems with Oroville Spillway happened almost immediately after construction.

“Lots of capable people looked at this thing over the course of 50 years and it escaped all of them,” said John French, the team leader.

He says the spillway was designed in the 1960’s by someone who had no experience working with spillways. Cracks and drainage issues were noted within a year of construction but were never addressed.

“It got accepted that spillway was working with these conditions, they’re normal, they’re okay,” Explained French about the mindset of inspectors over the years.

Multiple agencies over 50 years missed opportunities or ignored warning signs. According to the report, the land was not suitable for a spillway. Over time, concrete deteriorated and steel bars rusted.

“Are you kidding? I stay off with their heads,” said one Oroville resident, “they have to change. This is unacceptable.”

People living below the dam are furious about the findings and the Department of Water Resources’ ability to operate and maintain the nation’s largest dam.

“I think some perjury prosecutions need to take place, I think some people need to go to jail,” said Don Blake, an Oroville resident, “this has got to come to an end.”

French says the Department of Water Resources, which owns and operates the dam, doesn’t bear full responsibility. He says Federal and state regulators also had opportunities to step in but didn’t.

“What will be most productive is if we learn why this happened and how we can change things to prevent similar things from happening again,” explained French.

DWR did respond to the finding saying, “We will carefully assess this report, share it with the entire dam safety community and incorporate the lessons learned going forward to ensure California continues to lead the nation on dam safety.”

According to the report, those lessons learned include a review of original design and construction plans for all dams and spillways. And to designate one person to be the head of dam safety.