Lake Oroville is California's second-largest reservoir and the dam is the tallest such structure in the US. "The emergency spillway meets FERC's engineering guidelines for an emergency spillway".
At a 1:45 p.m. news conference in Oroville, officials said the threat of a concrete wall collapsing at the head of the emergency spillway has been minimized and residents can return home. "The guidelines specify that during a rare flood event, it is acceptable for the emergency spillway to sustain significant damage".
"Dams, bridges, roads and all ports around the country have fallen into disrepair", he said. While watching the emergency spillway revealed signs it could collapse on Sunday, Stork was present to see how events played out.
A document released by three environmental groups more than a decade ago said that the dam's "ungated spillway" design could result in the "loss of crest control" and threaten people's lives.
The state water resources department said crews using helicopters would drop rocks to fill a huge gouge, and authorities were releasing water to lower the lake's level after weeks of heavy rains in the drought-plagued state.
City personnel inspect San Diego's dams on a weekly basis for things such as erosion, leaks or anything that could compromise the integrity of a dam or spillway, such as brush and tree growth, rodent holes and fallen boulders; cracks are measured monthly, according to the Public Utilities Department.
At this time experts are not concerned that rising water levels will pose a threat. "I think that will be sufficient".
Water flows into the Feather River, and from there into the California Aqueduct, supplying farmers in the Central Valley and municipal water departments in Southern California.
Evacuation orders for almost 2,00,000 people living below the tallest dam in the United States remained in place early on Monday after residents were abruptly told to flee when a spillway appeared in danger of collapse.
State Water Project contractors, including the Metropolitan Water District of Southern California, were involved in the relicensing.
"They did look at that issue and they determined that [the existing emergency spillway] did meet the appropriate FERC guidelines", Kightlinger said.
"We did not say it was a cost issue", he added. But I welcome more scrutiny.
On Friday, Brown requested a Presidential Major Disaster Declaration for recovery efforts following January storms that tore through California, causing flooding, mudslides, power outages and damage to critical infrastructure. "We're in a very complex society where things can go wrong", he said.