Posted on 02/12/2017 4:26:47 PM PST by janetjanet998
Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]
The Oroville Dam is the highest in the nation.
Quite possible, likely even. PG&E owns some of the upstream generation, and they will regulate output to a schedule just as we do at TVA. All depends on the power load curve and other priorities (lake levels, river levels, etc.).
I’m not sure when the 6th unit is due back. I recall reading that they had shipped the 6th turbine out for the installation of new blades, but I’m not 100% sure of that. Without the turbine, of course, the 6th unit cannot pass water.
Re: 2458 - It seems that they’ve re-routed the flow down the spillway, perhaps to work on/under the right side. Sandbags upstream again, I suspect.
Resume: Expert in Spillway Failures from Hydraulic Jacking - joints, cracks in spillway…
Points of note underlined in this particular resume. Mr. John Trojanowski (expert in Stagnation Pressure "hydraulic jacking" failures/design issues in dam spillways).
They already know what was wrong - so do other dam owners around the world too by now..
Yes they diverted the waterflow to do more emergency repair drilling on the right side of the spillway. See the image in post 2,444. You can see the "mud" type flow from drill work that left its traces on the lip and edges of the concrete.
What is of interest is the debris that has a look of fiber clumps. Not sure what this is - if it is just simply dirt with grass. If so, this would have to have come from the inlet to the spillway (can't imagine workers clomping around on the spillway with clod & dirt with grass - but it's possible).
Seems that Mr. Trojanowski (a cool name that brings me back to the city of my youth where seemingly everybody’s last name ended in “ski”, “sky”, or “ovich”) has the right background for this situation.
I noticed that John France has worked on 3 dams with which I am remotely familiar - Wolf Creek in Kentucky, and Center Hill and Chilhowee dams, both in Tennessee. While the scope of those jobs are certainly different (Wolf Creek required a complete “Grout Curtain” at the base of the concrete dam to deal with erosion and piping issues that had plagued the dam since construction in the early 1950s), I’m sure that he brings some share of experiential expertise also.
This entire episode has been quite educational and intriguing. If I wasn’t late in my career already, I’d be considering moving into this area.
Don’t look now, but the flow is way up for the last hour. Hydro-chicanery.
I think there were errors the past few hours first underestimating then overestimating
I read somewhere else that the inflow is indeed calculated by the known outflow and the lake level change
looks like the lake level was in error with false decreases..messing up the inflow numbers
also looks they they changed the the path of the water seepage...it was directed all the way to the right of the main spillway
Possibly, though I think they might be changing release levels upstream from the reservoir.
I liked it better when the incoming numbers dropped though. :)
If they stay with their stated safety factor of 265 foot maximum,
they only have 26 inches left to go.
The lake level rose about 5 inches in the last 24 hours.
They’re anticipating releasing possibly on Friday. They also said that it will be at a rate of 40,000 to 50,000 cfs, so it will be a pretty strong release. I suspect that once they do, they’ll drop it down to about 845 or so before they close down the spillway again. Just a guess.
Hopefully, they won’t be washing down a lot of fresh debris as that could cause issues for the plant. I know that they’re thinking about that issue.
That was a great update.
Thanks!
There are many reservoirs in the Feather River basin.
http://www.sacriver.org/aboutwatershed/roadmap/watersheds/feather/upper-feather-river-watershed
Frenchman Lake is a 25 minute drive from my home. Snow is very deep(in the typical places) and the lake is full.
More pictures have been added.
It sounds like they may be holding back somewhat upstream to allow time to prepare for using the main spillway at Oroville again. I wonder if, when they open it up, they will open up also upstream so that inflows increase into the Oroville Reservoir...
The Almanor sensor is still not recording data.
https://cdec.water.ca.gov/cgi-progs/queryDaily?ALM
Rumor is it is very near full. I sent an email to a fishing guide there. We will she what he has to say.
Thanks - looking forward to hearing back about Almanor. Given the coming melt, I would think they they’ve been releasing water as much as possible. If I recall, that lake only releases something like 5000 cfs, though I could be quite wrong.
Yes, thanks for the interesting update.
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