California officials are trying to speed up repairs on Oroville Dam’s battered flood-control spillway. The Department of Water Resources have asked federal regulators to let it demolish and replace an additional 240 feet of the spillway’s 3,000-foot concrete chute before the rains comes this fall, leaving less work for next year. That 240-foot section originally was going to be replaced next summer as part of the two-year plan for repairing the spillway, whose massive structural problems in February sparked the emergency evacuation of 188,000 downstream residents.