The cataclysmic 10 inches of rain have failed to materialize. As of the time of this writing, inflows into Lake Orovilles are still manageable.
Above is a photo showing the damage to the primary spillway, taken three days ago when they had stopped the flows over it. I do not own this photo: I believe it belongs to the Associated Press, but I hijacked it from a blog that did not attribute it. My use of it here should be considered ‘fair use,’ but I’ll gladly take it down if anyone wants to be a dick about it.
Here is another hijacked, fair-use qualifying picture of what it looks like when water flows down and hits the hole.
Now, there had been a lot of anxiety that water diverting from the spillway off to the right would erode back into the reservoir, causing a catastrophic failure. Every competent person to whom I have spoken has indicated that this is impossible in the short term. Although it looks bad, that is because most of the topsoil has been removed. Water is now flowing over bedrock, which erodes far more slowly. Although it is not ideal to use the spillway in this condition in the long-term, we have been assured that it does not create an immediate risk.
So although this doesn’t encapsulate all of the details, the reason we had to evacuate, in essence- follows: Damage to the primary spillway caused engineers to reduce flows down that system. Lake inflows raised water levels to 901 feet, causing water to flow over the earthen, emergency spillway. Water going over the emergency spillway started to erode the earth under the “concrete lip,” creating a risk of weakening the ground under the lip (of the emergency spillway) which could have resulted in the top 30 feet of the emergency spillway collapsing, flooding every town on the feather river to the south. So they evacuated, and started hammering water out of the primary spillway, with the goal of reducing lake levels to the point that the emergency spillway would not have to be used during the storms that are currently occuring. Over the past several days, the lake levels have been reduced by about 50 feet.
So, long story short, there isn’t really a threat of a failure at the dam. More of a problem is the incoming rain and increased outflows at the dam may create localized flooding downstream.
I think we are pretty much in the clear. It might rain a lot, and we’ll likely lose power, but I don’t think we’re going to have to bug out again.
Here is a blurry dog photo.
There are a number of conspiracy theories floating around about the dam. I have run most of them to their source and found none credible. The National Guard is not preparing to evacuate everyone to Merced. There is not a Governor-directed media black-out. Illegal immigrants did not break the dam by soaking up all of the infrastructure money. God is not punishing California for whatever.
Although I still worry about the citizens of Oroville, we are pretty much in the clear down here in Yuba City. So long as the levees hold. Which they should.