February 14, 2017
The Sunday night mandatory evacuation of 200,000 people in the area below Oroville Dam, including Marysville and other communities, has been lifted as of 1:00 p.m. today (Tuesday) and residents are free to return to their homes. Butte County Sheriff Kory Honea said “it is safe to reduce the order to an evacuation warning” which means that residents must remain vigilant “in case the situation changes”.
Damage to the main spillway from the dam after a series of heavy storms resulted in reduced outflows and filling of the lake to capacity. This necessitated opening the emergency spillway for the first time in the 48 year history of the structure. The area below the emergency spillway was unpaved, causing concerns that the spillway itself could be undermined. That triggered the evacuation order on Sunday evening.
By Tuesday afternoon, clear skies resulted in reduced flow into the lake behind the dam. Increasing outflow to 100,000 cubic feet per second gradually dropped the water level from 901 feet to 889 feet, eliminating the need to utilize the emergency spillway.
Governor Jerry Brown had declared an emergency, seeking federal assistance. In praising the Department of Water Resources, he said “we have to depend on the professionals and the engineers. They tell us what we need, and then we do it.” Acting DWR Director Bill Croyle said “our goal is to remove as much water from the reservoir as possible so we don’t have to use” the emergency spillway, which is currently being strengthened by placing large rocks into the eroded area. Meanwhile, DWR observed “there is no further erosion of the (main) spillway” and “clear water is coming out because it’s hitting bedrock.” DWR’s goal is to reduce the lake level to 850 feet by this weekend.
PECG commends the DWR Engineers and other personnel who responded and worked around the clock to address this emergency situation, as well as Caltrans personnel who facilitated the evacuation Sunday night.
The Caltrans District 3 Marysville office was closed on Monday and Tuesday and affected employees were provided with paid Administrative Time Off (ATO). Caltrans has informed PECG that employees are expected to return to work on Wednesday but “management will certainly consider employee requests to take additional time off on a case by case basis.”