OROVILLE, Calif. - The head of California's water agency says repairs to the damaged concrete spillway at Oroville Dam will cost between $100 million and $200 million.

Department of Water Resources Acting Director Bill Croyle said Tuesday that teams are already working on plans for repairing the dam's main spillway.

Croyle says the preliminary cost estimate is based on limited information. He says long-term repairs will likely begin after the spring runoff season, when crews can close the floodgates for an extended period without the lake refilling with melting snow.

In the meantime, crews are working aggressively to fortify an adjacent emergency spillway, where erosion threatened to undermine a concrete wall that holds water in the reservoir.