Construction crews have begun demolishing the destroyed portion of the main spillway at Oroville Dam as they race to repair the structure in time for the next rainy season.
State water officials and construction managers said Wednesday they expect to begin pouring fresh concrete in June, starting at the bottom of the 3,000-foot chute and working their way up.
The spillway is the main outlet for Oroville Dam, the country's tallest.
Huge swathes of the spillway began washing away in February. When a second, emergency spillway also began giving way Feb. 12, authorities ordered the temporary evacuation of 188,000 people downstream.
Crews aim to replace the lower portion of the spillway by Nov. 1, when winter rain and snow increase the flow of water into the lake.