This aerial view looks east toward Oroville Dam and Lake Oroville, showing the damaged spillway with its outflow of 100,000 cubic feet per second (cfs) at the Butte County site. The California Department of Water Resources has a goal to lower the lake level by 50 feet to handle the next round of winter storms. Photo taken February 15, 2017. Dale Kolke / California Department of Water Resources

Spectators view water cascading into the Feather River from the damaged Oroville Dam spillway on Saturday afternoon in Butte County. Oroville Dam itself remains safe and there is no imminent threat to the public. Photo taken February 11, 2017. Dale Kolke / California Department of Water Resources, FOR EDITORIAL USE ONLY

Water flows down the auxiliary spillway at Oroville Dam on Saturday, February 11, 2017, after the lake level exceeded 901 feet elevation above sea level. The volume of water is expected to pose no flood threat downstream and should remain within the capacity of the Feather River and other channels to handle. Oroville Dam in Butte County itself remains safe with no imminent threat to the public. Florence Low / California Department of Water Resources

Heavy equipment operators dig access points to the riverbank to allow heavy equipment access to remove the sediment and debris from the diversion pool area just below the damaged spillway at Oroville Dam in Butte County. Photo taken February 17, 2017. Brian Baer/ California Department of Water Resources

Old Route 49 bridge crossing over the South Yuba River in Nevada City, Calif. saw local and regional visitors during the atmospheric river event across Northern California on January 9, 2017. Kelly M. Grow/ California Department of Water Resources, FOR EDITORIAL USE ONLY

A night view of the damaged Oroville Dam spillway as the California Department of Water Resources increased the outflow form the Oroville Dam spillway from 55,000 cubic feet per second (cfs) to 60,000 (cfs), in anticipation of the expected increase of inflows into Lake Oroville from the latest round of winter storms. Photo taken February 20, 2017. Zack Cunningham / California Department of Water Resources

Rescue swimmers and aircrewmen from Coast Guard Air Station Cape Cod, Mass., conduct hoist training evolutions June 23, 2015. The MH-60 Jayhawk Helicopter pilots steadied the aircraft while the flight mechanics lowered and recovered the rescue swimmers to simulate recovering people in distress. (U.S. Coast Guard photo by Petty Officer 3rd Class Ross Ruddell)

An aerial view of the Oroville Dam site and with a huge debris field in the diversion pool area just below the damaged spillway. The California Department of Water Resources gradually reduced the outflow from the spillway from 50,000 cubic feet per second (cfs) to zero on February 27, 2017. The reduction allows work to begin to remove the debris and reduce water surface elevation in the diversion pool, so the Edward Hyatt Powerplant can go operational. This will allow for better management of reservoir levels during the upcoming spring runoff season. Photo taken February 27, 2017. Dale Kolke / California Department of Water Resources