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weirdness in norcal

Daveroo

Members +
middle of last week we had one warm storm after another,then at some point the powers that be noticed an irregularity in the spillway at lake oroville.they stopped the flow to see what was going on,and found a huge hole in it.while they were looking at the damage,the lake was still filling,rapidly.the spillways capacity is well over 100,000cfm,its was only flowing at less than 30,000cfms until this morning,BUT yesterday morning at 8:26am pst,the water began to flow over the emergency spillway,which isnt more than a low concrete wall next to the main spillway,and is only a fewe (25?) feet lower than the top of the dam. the dam is the tallest earthen dam in the USA,the local news was saying the tallest period in the US,even taller than the hoover dam,but id have to look at the numbers to believe that.
so the situation today is that the water was almost 2 feet above the top of the concrete top on the emergency spillway.with more than 130,000 cfm coming into the lake,and only 40,000cfm out of the mail spillway,and the earth infront of (down stream) and under the emergency spillway wall is now earoding from under the concrete.and at 4pm they announced an imminent colapse,saying it would happen by 5,5:30 pm at the lastest,so now they are evacuating every one along the feather river,from yuba city to oroville.not sure on the mileage,but its aways.
they started to reliese 100,000 cfms in the main spillway,which has lowered the water over the concrete,but hasnt lessened the threat down river.nor the threat to the concrete.

around 6pm,cal fire had dispatched all of the handcrews here in NYP,which borders the butte ranger unit,oroville is in that responce area,as well as two engines and a bulldozer,also heard my dozer operator buddy on the air in butte,he came from the redding area.

to say the least its a mess at the moment.
 
Wow I'd the folks in Oroville. When I lived in Northern California our rains were consistent and the snowfall occasionally got a little high but not life threatening. It's like Texas, we went from 5 year drought and lost so many lakes, now they are all overflowing causing havoc for the Corps of Engineers. Stay dry Dave!
 
This morning, FOX news reported rocks were being dropped by helicopter into the hole in the spillway to prevent further erosion... good luck with that. I read 188,000 evacuated.

Dick
 
I grew up in the Bay Area, and spent a year at school between Marysville and Oroville, so I know the area pretty well. As txnetcop mentioned, our rain/snow falls were a lot more consistent then. But at least you've got lotsa water now :D
Stay dry, and SAFE.
Pat☺
 
This morning, FOX news reported rocks were being dropped by helicopter into the hole in the spillway to prevent further erosion... good luck with that. I read 188,000 evacuated.

Dick

Saw the Army doing the same thing with CH-47s in New Orleans right after Katrina.

All of the attention seems to be directed toward the emergency spillway. No word about the main dam, which I guess is still all right. I have noted a whopping hole in the bottom of the dam's regular spillway - 100,000 cufps is guaranteed to seriously erode that thing. One thing that interested me was to look at the edges of that big hole in the floor of the spillway and not see any traces of reinforcing steel around the edges of the hole.
 
Hey All,

In addition to that spillway and dam I read somewhere the levees in the delta were near failing...

And four more inches of warm rain on snow coming...

Need to check these to be sure but maybe some of you know.

-Ed-

Update Levee breach potential validated - evacuations already...

http://sacramento.cbslocal.com/2017...of-walnut-grove-due-to-imminent-levee-breach/

Dan Swain's blog on CA weather is outstanding and supports what I said... I suspect weather service will say the same.

http://weatherwest.com/
 
I read today that the spillway has never before been used (51 years). If so, it failed on the first run. Maybe a little rebar would have helped.

Dick
 
I know your nowhere near the Dam or Oroville.
Be safe bud. It dont look good at all.
I hope your mom is doing better bud. Take care of yourself.
Craig.
 
I read today that the spillway has never before been used (51 years). If so, it failed on the first run. Maybe a little rebar would have helped.

Dick


Two spillways failed on first use. Doesn't say much for the contractor, or even worse inspections that knew about the fault and let it go. Bear in mind that this dam was built on a bond debacle and long term maintenance probably was not given serious consideration.

Update: The mandatory evac has been lifted and changed to voluntary. Like Ed pointed out there is much more water coming, warm storms and massive spring runoff. This is going to be an on going threat, so if you are in the area keep your situational awareness on WFO.

The inflow is approx. 2x what can be let out during peak storms. The lake can re-fill in a very short time and reach the top of the e-spillway. The main spillway is already FUBAR, but the bedrock ridge between that structure and the actual dam should act as a containment. Hopefully...

The e-spillway sits on a terrain feature that is very shallow, so the actual pressure against that structure is only elevated at absolute peak. Even if that structure erodes, the hydrodynamics are not entirely un-manageable.


All that said, I hope the people who's homes and lives are in the flood plain are able to go back in, retrieve their belongings and animals, then find suitable re-location until the engineering is resolved.

This entire scenario is far from under containment.


NorCal Weather Side Note:

Six months ago, I moved away from NorCal Eastern Sierra. Current snow loads are now so massive, my home is in jeopardy of being badly damaged or destroyed.
My wife and I are moving back to protect the house. :dizzy:

Friends have been posting video of their homes buried six feet below snow grade. Entire neighborhoods are buried, and the infrastructure has been so depleted by budget cuts, everyone is pretty much on their own.

I'm not whinging about the move, which is badly timed and an inconvenience. I look at the Oroville situation and thank my lucky stars that my rather insignificant problem is...well...rather insignificant.
 
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the local news was saying the tallest period in the US,even taller than the hoover dam,but id have to look at the numbers to believe that.
Yep - I heard it was 13 ft higher! The whole spillway looks like a total f**kup - I'd be hunting down the people who were in charge of installing the spillways - something seriously wrong there.......
 
This things needs some Yakety Sax over layed to make it less depressing.
 
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