A damaged flood control spillway at the Oroville Dam may have to be used as early as next week as storm runoff and snowmelt continue to fill the massive reservoir on the Feather River, state water officials said. The spillway has been dry since Feb. 27, when engineers with the Department of Water Resources rapidly reduced the flow of water down the concrete chute from 50,000 cubic feet per second to zero so they could repair the spillway and restart a nearby hydroelectric plant.