As a test run at the Oroville Dam spillway commenced Wednesday afternoon, the director of the Department of Water Resources said at a press conference in Sacramento he expected the bottom of the spillway to be eroded away by spring, with a replacement completed by fall. This came after a gaping hole in the spillway at the Oroville Dam, the tallest dam in the U.S., appeared Tuesday morning. The hole in the spillway is 180 feet wide and 30 feet deep, DWR public information officer Eric See said.