The California Department of Water Resources (DWR) just issued this updated statement regarding the expected failure of the auxiliary spillway at Oroville Dam in Butte County. The agency noted that “Oroville Dam itself is sound and is a separate structure from the auxiliary spillway.”
The agency also said DWR has doubled the flow down its main spillway 55,000 cubic feet per second (cfs) to 100,000 cfs to avert more erosion on the auxiliary spillway.
In a press conference in Oroville at noon, Eric See, DWR public information officer, said, “the flows from the auxiliary are on the decline and the overall conditions are stable,” but the situation has changed dramatically since them. Here is the complete statement:
“Based on information received from the California Department of Water Resources (DWR) and the incident command team managing Lake Oroville, counties and cities near Lake Oroville and the surrounding area issued evacuation orders for residents. The concern is that erosion at the head of the auxiliary spillway threatens to undermine the concrete weirand allow large, uncontrolled releases of water from Lake Oroville. Those potential flows could exceed the capacity of downstream channels.
To avert more erosion at the top of the auxiliary spillway, DWR doubled the flow down its main spillway from 55,000 cubic feet per second (cfs) to 100,000 cfs. The next several hours will be crucial in determining whether the concrete structure at the head of the auxiliary spillway remains intact and prevents larger, uncontrolled flows.
Current flows are contained with downstream channels.
Flow over the auxiliary spillway weir began Saturday morning and has slowed considerably. DWR officials expect that flow to stop entirely soon, which will reduce the erosion on the downstream side of the structure.”
At 6:08 pm the National Weather Service Sacramento issued a statement via Twitter: “#OrovilleDam itself is not compromised at current time. Failure would be on auxiliary spillway.”
Local agencies in regions that could be impacted by the auxiliary spillway failure also issued emergency evacuation orders.
The Marysville Police Department tweeted: “An emergency evacuation of the City of Marysville and Yuba County has been issued.”
Caltrans District 3 tweeted, “Marysville/Yuba County now being included in the evacuation notice due to Oroville Dam emergency spillway potential failure.”
@NewsCenterHQ, in a tweet, said: “#BREAKING NEWS: Evacuations affecting up to 100,000 people in southern Butte County, CA. #OrovilleDam”
The City of West Sacramento emphasized in a tweet, “There are NO evacuation orders for the City of West Sacramento. Releases from Oroville Dam will dissipate in the Sutter and Yolo Bypasses.”
Nbcbay.com issued a #BREAKING UPDATE via Twitter: “Freeway jammed with cars as people evacuate area where Oroville Dam may collapse.”
This tweet shows the confusion that some media outlets are having in understanding the difference between Oroville Dam, the primary spillway and the auxiliary spillway. Actually Oroville Dam is not in danger of collapsing; it’s the auxiliary spillway that could fail.
The San Francisco Chronicle accurately reported on the evacuation order: “Butte County residents near Lake Oroville, including the entire town of Oroville and nearby regions, were ordered to evacuate Sunday evening after the emergency spillway next to the reservoir’s dam suffered a possible structural failure, officials said. ‘There has been severe erosion of the emergency spillway and a possible structural breach that could send uncontrolled water down the stream,’ said Chris Orrock, a spokesman with the California Department of Water Resources.
Residents downstream from Lake Oroville to the Sutter County line were under a mandatory evacuation order. Counties around the reservoir, the second largest in the state, down to Sacramento were warned about the possibility of flooding.”
Read more from the San Francisco Chronicle here: Evacuation ordered for Oroville as dam spillway expected to fail: http://www.sfchronicle.com/news/article/Lake-Oroville-discharging-water-over-dam-s-10926950.php?cmpid=twitter-premium
The California Department of Fish and Wildlife reported some good news on their Twitter page: Feather River Hatchery evacuated. All personnel safe and accounted for.#OrovilleSpillway.”
Finally, Mark Finan of KCRA 3 TV reported: “8pm, Lake Oroville was at 901.02′. Flow is now ending over the emergency spillway.”
Lets all pray and hope that the auxiliary spillway doesn’t fail. My heart goes out to everybody impacted by the evacuation.
I will post more updates from local, state and federal agencies, media and NGOs as I receive them.