Members of the Association of State Dam Safety Officials and the U.S. Society on Dams carried out an independent investigation into the human and technical problems that caused the crisis at California's Oroville Dam. The experts issued their report Friday.
Both spillways at the half-century-old Oroville Dam gave way in February 2017, forcing 200,000 people downstream to be evacuated. The feared uncontrolled release of massive amounts of water over the top did not happen, and residents were allowed to return home days later.
The independent panel of dam safety experts say the structure had inherent design and construction weaknesses.
The crisis started when massive chunks of the dam's main concrete spillway suddenly began washing away.
The report faulted California's Department of Water Resources, which owns and operates the dam, an anchor of California's water system, and dam regulators for allegedly failing to recognize and address problems in the 770-foot structure over decades of inspections and reviews.
The report states the original spillway designer was hired out of a postgraduate program in the late 1960s. He had very limited engineering experience and had never designed a spillway before.
It goes on to say cracks, which were the root of the problems last year, were first reported as early as 1969, but over the years they had been overlooked.
The state has said repairs to the structure will cost more than $500 million. Residents and businesses downstream, including in the 19,000-resident town of Oroville at the foot of the dam, have filed more than $1 billion in damage claims.
"Repairing a dam is great ... but what's happened to the view of Oroville as a safe place to live?" asked David Steindorf of American Whitewater, one of the environmental groups that had long complained that the state ignored concerns about the dam's construction flaws. "There's a lot of long-term impacts that need to be addressed."
Few in Oroville FOX40 talked to Friday were the least bit surprised by the report's findings.
"We saw them trying to repair the cracks in that thing a couple of times and looked at eachother and said, 'Wait a minute, this doesn't look right,'" said resident Joeline Webber.
"You got to trust them? Wrong! And that's the way all of us feel," said Sony Teddleton.
Genoa Widener started the Facebook page "Not Just a Spillway" and has since been collecting signatures asking the federal government remove and replace the DWR as the operator of the Oroville Dam. The nearly 500-page independent report had many flocking to sign Widener's online petition.
"Online does have about 400 signatures as of now," Widener told FOX40 Friday. "I posted it this morning."
Widener says the overwhelming feeling of mistrust around her hometown was a major reason she started doing what she could to get the dam in the hands of another agency.
"It's my community and somebody just needs to step up and say enough is enough," Widener said.
The experts said the Oroville crisis made clear that it was essential for dam managers and inspectors to review original dam construction in light of modern engineering practices.
"Like many other large dam owners, DWR has been somewhat overconfident and complacent regarding the integrity of its civil infrastructure," the experts said.
In a statement, Joel Ledesma, a deputy director at the water agency, said state officials had supported the independent review "so we can learn from the past and continue to improve now and into the future."
"We will carefully assess this report, share it with the entire dam-safety community and incorporate the lessons learned going forward," Grant Davis, the agency's director, said in the statement.
The water agency said it would assess its organizational structure as a result of Friday's findings and already was assessing its dam-safety program.
Dam experts said the Oroville crisis is a warning for operators around the world.
"The fact that this incident happened to the owner of the tallest dam in the United States, under regulation of a federal agency, with repeated evaluation by reputable outside consultants, in a state with a leading dam safety regulatory program, is a wake-up call for everyone involved in dam safety," the experts' report said.
The average age of the more than 90,000 dams in the U.S. is 56 years, making thorough inspections and maintenance increasingly important for the safety of people downstream, dam experts said.