Sunday, February 12, 2017

Officials warn of “imminent failure” at Oroville Dam’s emergency spillway

Immediate evacuation from the low levels of Oroville and areas downstream is ordered.
A hazardous situation is developing with the Oroville Dam auxiliary spillway. Operation of the auxiliary spillway has lead to severe erosion that could lead to a failure of the structure. Failure of the auxiliary spillway structure will result in an uncontrolled release of flood waters from Lake Oroville. In response to this developing situation, DWR is increasing water releases to 100,000 cubic feet per second.
Immediate evacuation from the low levels of Oroville and areas downstream is ordered.
This in NOT A Drill. This in NOT A Drill. This in NOT A Drill.
Chris Orrock, a spokesman for the Department of Water Resources, told The Bee the failure happened as the bottom of the emergency spillway began to erode.
“It happened quickly,” he said. 
Sutter County also put out an alert on Facebook:
We have received information about the potential for increased flows in the Feather River of as much as 100,000 cubic feet per second. We are gathering as much information as possible and will be providing additional information as soon as it is verified.

Officials are warning those living downstream of Lake Oroville’s dam to evacuate because of a risk that the dam’s emergency spillway could collapse.
“They have what they expect to be an imminent failure of the axillary spillway,” said Mike Smith, a spokesman for the California Department of Forestry and Fire Protection. “What they’re expecting is as much as 30 vertical feet of the top of the spillway could fail and could fail within one to two hours. We don’t know how much water that means, but we do know that’s potentially 30 feet of depth of Lake Oroville.”
The Department of Water Resources, which operates the dam, said in a 4:42 p.m. Twitter post that the emergency spillway could fail within the next hour. 
“Oroville residents evacuate northward,” the Tweet said.

Well, and I thought they had dodged the bullet at least for a couple of days.

So, just before I saw this, I got off the phone with a friend who has some knowledge of this sort of thing.  He told me that the emergency spillway shouldn't be necessary to use absent a 1000 year event.  He feels that the management of this was exceptionally poor to allow this situation to develop.  We also had big floods in 97 and 86, and nothing like this occurred.  He speculated that the people in charge were far more concerned than they let on.  He was especially dismayed that they were playing such games as changing the name of the emergency spillway to the "auxiliary" spillway.

Further, he told me the water content of this years snowpack is exceptionally high. This spring, they are expecting high runoff for weeks at a time.  Before we knew the emergency spillway was going to fail, he told me the job of the water managers for the next three or so months would be to get as much water out of the reservoir as they possibly could.  Now, it may be that that issue is moot.

If the emergency spillway fails, there is no telling how big of a hole the water will carve, but enormous energy will be released.  Whatever it does, from that point on the river flow from now through  the spring melt will be uncontrolled to great extent, and will very likely wreck havoc downstream.  Levees in the valley will almost certainly fail. Oroville will suffer extreme damage.

Not good at all.  Three days ago the water managers were telling us they didn't think the water would ever get to the top of the emergency spillway.  Now, disaster looms.

Finally, someone on social media posted a picture of an inspection of the main spillway that was done back in 2015.  Trucks were parked at about the exact spot were the spillway failed.  The question was asked if those responsible actually knew of a fault, but didn't do anything.  Who knows, but I believe that very probably, there was a fault that was identified, but the authorities, dealing with a limited repair budget and a drought, shelved the problem pending further money and seemingly a wealth of time.  Note, this is speculation, but an investigation will be inevitable.  I hope the shredders at the state water department have been secured, lest evidence disappear. 

The Feather River flows right through the middle of the Marysville/Yuba City metropolitan area.  Further downstream, Sacramento and the delta.

Read more here:

Read more here:

1 comment: