The failure of the spillway wasn’t just a scary experience for Oroville, but also a costly one for a city that was already struggling financially. Right now, costs are up by millions of dollars, but it’s crucial to repair the dam which provides water for more than 25 million Californians. Kiewit construction crews continue to be hard at work making repairs on the Oroville Dam Spillway. Construction is being done in two phases, with the first completed in November.