US
From The Daily Caller
Tim Pearce
Energy Reporter
5:19 PM 08/11/2017
California is receiving $22.8 million from federal disaster officials to aid in cleanup procedures for the February collapse of the Oroville River Dam spillway, the Federal Emergency Management Agency announced Wednesday.
The Oroville River Dam crisis led Lake Oroville to overflow and endangered hundreds of thousands of people.
Both federal and state governments had been warned about the condition of the spillway from as far back as 2005. The crisis caused $500 million in damages. California contends the federal government should pay 75 percent but, depending on the findings of federal investigators, the state may receive significantly less, the Ventura County Star reports.
“That [$22.8 million] was just the first of many reimbursements,” California Department of Water Resources (DWR) spokeswoman Erin Mellon said, according to the Ventura County Star.
Despite what Mellon says, emergency federal funds to the state may be cut off if federal regulators believe the crisis was caused by lack of routine maintenance.
“Is there a maintenance issue here, because they’re not going to cover that. If it’s an emergency response, they’re going to cover,” then-DWR director Bill Croyle told lawmakers in May according to the Ventura County Star.
Three environmental groups filed a petition to Federal Energy Regulatory Commission (FERC) to reinforce the Oroville River Dam spill in 2005. The groups claimed that the dam, completed in 1968, did not meet modern safety standards. FERC rejected the petition on the advice of the California DWS, The Mercury News reports.
During the dam’s last inspection in 2015, regulators inspected the spillway “from some distance,” the regulators’ report said according to the Redding Record Searchlight.
HT/TA
I will. And as a taxpayer (if you are), you should too. It is the death of a thousand cuts (or more). Billions and billions are wasted this way just at the Federal level. If you add in all the state and local governments it is a staggering amount. I know for a fact that I pay well over 50% of my income in Federal, State, and Local taxes and fees. It is infuriating to think that so much of it is wasted by incompetent/corrupt government officials. Frankly, if you are not outraged, then you are part of the problem.
Best media coverage of the Oroville Dam is by this vblogger:
https://www.youtube.com/user/blancolirio
Over the last six months, Juan Browne has created 56 (and counting!) fascinating videos about the Oroville Dam situation, averaging 12.2 minutes each. If you want to understand the topicin depth, be prepared to burn 11.4 hours to watch it all at normal speed, or 7.6 hours at 1.5x speed.
Phil. (August 16, 2017 at 5:41 am )
I’ve been busy this week but decided to check back to this thread. Thanks for your input. You seem to be informed of the flows , pool elev, etc. I looked into it as it was happening and pretty much moved on since.
If you are an engineering type with basic hydraulics understanding and an understanding of a ballistic curve (basic physics of horizontal velocity vs acceleration of gravity) it is relatively simple to plot a back of the envelope curve. Locate the profile of the discharge chute (spillway) and bring your ballistic curve of the water onto the chute below the ‘ski jump’. If I find time I’ll look over my always cluttered desk and maybe I can find the notes I used in my earlier calculations and show my work. But to be honest my tractor repairs are much more important to me now.
There are two ways to get 90,000 cfs through the chute. Lower velocity and deeper depth OR higher velocity and less depth. If the operator allows the pond level to rise 50 ft before release then the discharge will be under higher pressure and therefore the velocity will be much greater for a given flow rate. The ballistic curve will change at the ‘ski jump’.
If the original design was done to allow for releases to begin to maintain pool elev at I believe was about 814′ (bottom of spillway ?) and the operator brought the pool elev up another 50 ft or more to bank/conserve water then that could have led to a flow velocity exceeding the design criteria of the spilllway. Over 6 million lbs. of water per sec. accelerated by gravity and ….. well the result is obvious.
eyesonu August 18, 2017 at 7:02 am
If the original design was done to allow for releases to begin to maintain pool elev at I believe was about 814′ (bottom of spillway ?) and the operator brought the pool elev up another 50 ft or more to bank/conserve water then that could have led to a flow velocity exceeding the design criteria of the spilllway.
The floor of the spillway is at 814′ so until that is reached there can be no flow over the spillway. The practice is to maintain a certain head because if the flow into the valve is too shallow it can scour the inlet and cause damage. My understanding is that the optimum is about 850, it reached 820′ on 1/09 at which time the inflow was ~90,000 cfs, they gradually increased the outflow over the next couple of days (flood control rules limit how fast they can change the flow rate) and on 1/14 they had balance at about 849′ (23,000 in, 21,000 out). They balanced it between 849 and 854 until the 6th Feb, on the 5th the inflow was ~31,000 and outflow 30,000 cfs. The problem started the next day when the inflow went up to 49,000 they increased the output and still kept it about 850′ but then the break happened. Several more inches of rain increased the daily average inflow to 155,000 cfs, Water level went from 850 to 902 in a few days.
If the outflow is unrestricted at 852′ the outflow is 100,000 cfs.
On the 7th the hourly inflow rate went up from 77,000 to 132,000 in 6 hr, while the outflow was at 47,000 and then increased to 57,000 cfs the water level only went up a couple of feet to 854′, but that’s when the spillway broke. Inflow peaked at an hourly rate of ~190,000 cfs which rapidly pushed the water level over 900′.
The design criterion of the spillway wasn’t reached at anytime
HTH
Phil, I appreciate your dialog. As you carefully state “your understanding”, I’ll be rather blunt that your sources or “understanding” has more holes than a fishing seine.
To state that at low flow starting at 814′ would cause scouring is complete BS. An optimum flow at 850′? Optimum for what? Equal BS.
Please check your sources for your “understanding”.
I’ve simply offered insight here and not going to get into an absolute bullshit discussion with you.
You win! I will not play with you! Maybe someone else will.
Phil;, I cross checked your values as in the above comment of yours. What kind of BS are you pushing here?
http://cdec.water.ca.gov/cgi-progs/queryDaily?ORO&d=17-Feb-2017+08:15&span=30days
One more for you pertaining to your comment.
http://cdec.water.ca.gov/cgi-progs/queryDaily?ORO&d=18-Jan-2017+08:15&span=30days
eyesonu August 18, 2017 at 8:24 pm
Phil;, I cross checked your values as in the above comment of yours. What kind of BS are you pushing here?
http://cdec.water.ca.gov/cgi-progs/queryDaily?ORO&d=17-Feb-2017+08:15&span=30days
That’s the source of the daily averaged data and it confirms the values I used, e.g. I said:
“Several more inches of rain increased the daily average inflow to 155,000 cfs, Water level went from 850 to 902 in a few days.”
The site you referenced gives the inflow as 155498 cfs on 2/09.
I also referred to hourly data which can be found here:
https://cdec.water.ca.gov/cgi-progs/queryF?s=ORO&d=10-Feb-2017+04:40&span=12hours
You’ll see that the flow peaks at 190435 cfs at 19:00 on 2/09 as I said.
To state that at low flow starting at 814′ would cause scouring is complete BS. An optimum flow at 850′? Optimum for what? Equal BS.
You appear to misunderstand, I said:
“The practice is to maintain a certain head because if the flow into the valve is too shallow it can scour the inlet and cause damage.”
For example at a level of 830′ you could have a flow of 25,000 cfs according to the outlet graph in the manual and the depth at the inlet is 16′, if you release at the same rate but at a water level of 850′ you now have a depth of 36′. Thus the velocity in the inlet is reduced by more than a factor of two, substantially reducing the erosion. See for example:
http://slideplayer.com/slide/9479174/
This was explicitly addressed in one of the news conferences (Feb 15th), where they explained as the water level dropped they’d have to reduce flow to prevent erosion at the inlet.
W/r/t scouring the inlet, I believe I’ve heard Juan Browne say more or less the same thing that Phil said.
eyesonu, I think you might have missed the word “inlet.” He’s talking about the upstream side of the gates, in the reservoir. That side is not paved (maybe it should be!), and so if the flow rate over the gravel is too high it scours the inlet, moving rocks and gravel through the gates and down the spillway.
Dave and Phil; I did take Phil’s comment to refer to the gate?intake for the spillway chute. If there was an issue for scouring in the lead in channel in the lake I could not imagine that was not previously addressed with large rip-rap (quick and cheap fix). They build hurricane breakwater’s with it on sand bottoms for god’s sake.
Phil; Your above comment references dates beginning on Jan 9 and then ref Jan 14 and then continuing thru Feb 6. I had to spend a good bit of time to try and figure what you were trying to say. To be honest I was not concerned about the lake inflows. The lake levels will reflect that and is what is relevant. Keep in mind that my point was the water velocity in the discharge chute and the effect of a ballistic curve in the water it would entail.
I watched this saga 6 months ago and have no dog in this hunt and really could care less at this point as it is under control. It could have been a bad situation had circumstances (more rain, etc) been different. Anyway I don’t have time to continue with this discussion but there was a post on WUWT and I tossed out a comment pertaining to the chute. I still stand behind that comment and would like to divulge into a detailed calc with the proper documents necessary when I have time. It’s the kind of things I like to do. Inquiring minds want to know.
Quick note for any who may not grasp a quick pressure calculation on H2O pressure at depth. The pressure on the water at the bottom of the spillway gate with a 50′ pond/pool level above would be 3,120 lbs/sq ft. (over three thousand lbs. per sq. foot). The water would come out of the open gates quite forcefully and fast. If I have time I’ll show my work when I look into my hydraulics handbook. Anyways, I now have tractor parts in hand so back to serious/important work that I don’t need to explain.
A link to the profile and measurements of the spillway/chute and gates would be greatly appreciated. There was a lot of discussion on metebunk and I really don’t have the time to go through it again now.
If one of you hydraulic engineers would like to step in, have at it.
eyesonu August 18, 2017 at 11:31 am
Quick note for any who may not grasp a quick pressure calculation on H2O pressure at depth. The pressure on the water at the bottom of the spillway gate with a 50′ pond/pool level above would be 3,120 lbs/sq ft. (over three thousand lbs. per sq. foot). The water would come out of the open gates quite forcefully and fast.
As I showed above the dam operators were attempting to maintain a water level of 850′ (as their licensing conditions require them to in order to maintain the flood control reserve). Since the floor of the spillway is at 814′ that gives a depth of 36′ or about a pressure of 15psi (less than the water pressure in the faucet in your house).
The velocity is given by:
v=sqrt(2.g.depth)
Using metric units v= sort(2×9.8×10) = 14m/sec
Increasing to the hypothetical 50′ above the spillway would only increase the velocity to ~18m/sec.
If anyone wants to find what the spillway actually looks like they can find detailed specs in:
https://ia800302.us.archive.org/3/items/zh9californiastatew2003calirich/zh9californiastatew2003calirich_bw.pdf
pp63, hint it’s nothing like a ski jump!
Nice shot of the inlet at 6.16 in
Some pics of the ski jump:
https://www.metabunk.org/attachments/20170216-135932-rvyvp-jpg.24739/
https://www.metabunk.org/attachments/flr2014-jpg.24951/
https://www.metabunk.org/attachments/20170210-223837-9hube-jpg.24434/
Those photos are not of anything resembling a ski jump, eyesonu. Ski jumps are concave-upward. Those photos show a section of the spill way which is concave-downward.
Here’s what a ski jump looks like (with an ISIS skier at the 2014 Sochi Winter Olympics) :
http://robrogers.com/wp-content/uploads/2014/01/010214_Ski_Jump.jpg
Dave, you just need to attach the concave-downward slope of the spillway as shown in the photos and you got a winner!