Clues to Oroville Dam Spillway Failure ‘Were All There In The Files,’ Top Investigator Says

The clues that the main spillway at the Oroville Dam could fail were embedded deep in state records, but officials did not recognize the evidence before the structure broke apart in February, investigators said Tuesday. A history of damage when the spillway was used, cracking in the concrete surface and unexpectedly large amounts of water exiting drains under the deck should have raised suspicions that something was wrong. But annual inspections gave the state false confidence that the spillway could handle a big flood event, investigators found.