Some perspective:
Typical waterflow (at least in recent years) in the Feather River below Oroville Dam is less than 10,000 CFM. This is all the water sent through the dam for power generation, fish hatchery support, irrigation, etc.
The main spillway - the narrow channel to the left of the dam in the picture below - as of late last night was running at 100,000 CFM. It has the capacity to run 250,000 CFM, though of course it’s got a huge gaping hole in it right now (and probably much bigger now than in this image, which was taken before last night’s emergency. The spillway is 200’ wide so approximately a 20-lane freeway.
The “emergency” spillway is a non-adjustable concrete weir farther to the left of the main spillway. Actually two different weirs, but basically it’s the “lip of the bathtub”. When water gets that high, it’s going over the emergency spillway. There is no decision at that point. From what I could find, the emergency spillway was running at no more than 12,500 CFM yesterday when it started to erode. It is supposed to handle, I think, around 80,000 CFM
The emergency spillway holds back about 30’ of Lake Oroville’s total depth (which is about 700’ at the dam). If the erosion works backward to the weirs and undermines them, a 30’ wall of water (and trees, boulders, the concrete weirs, the parking lot, etc.) is going down the hillside, and 25 square miles (surface area of Lake Oroville) x 30’ of water is pouring out after it. It would be like sending all of Lake Sonoma or most of Clear Lake down the hillside over the course of a few hours.
It’s called the “emergency” spillway for a reason.
Oh, fun fact: there is enough material in the Oroville Dam to build a 2-lane highway around the Earth. I did not know that.
It will be interesting to see if Trump get any help going their way soon or will he be as inept as Bush was with NO. God there is so much stuff a president needs to do well that I just think Trump is going to fuck up even when he’s not trying to.
FOX: Sir Trump always said there is/was no drought in California. Liberals think only in terms of global warming. Lord Jesus gives us free water. Too much in fact.
Good thing we have the Best Infrastructure Anywhere.
FEMA was quite effective under Obama. Be it tornados in the Midwest or superstorms Irene and Sandy they were on the ground. I can attest to this first hand in the NYC area.
More perspective for people not in California (I’m not, but I’m from there). The collapse of the emergency spillway of Oroville Dam would release approximately the same amount of water onto the town of Oroville, and all points downstream, as the total volume of any of these reservoirs.
Source: Aquastat dataset for North America, using 500-600 million m3 as a range. http://www.fao.org/nr/water/aquastat/dams/index.stm
Last I checked, they were still getting btw 95000-100000 CFM coming into the lake so wed-fri will be critical
Today’s picture of the erosion near the emergency spillway. This is what caused the evacuation. If it erodes back to the weir, the foundation will be compromised and then it’s goodbye Hwy 70 corridor.
And here’s the forecast for Oroville:
They have 48-60 hours to shore up that spillway.
Yup. That weather report is what all of us who live in the area are talking about right now. I live about a 35 minute drive uphill from there. Our local fairground is one of a number of hosting sites for the evacuees. I guess there was a pretty big debate over what the emergency spillway could handle during the last relicensing for the damn.
I’m sure this dam is the only power producing site where anyone has ever overestimated its safety./s