California's Lake Oroville Main Spillway Severely Damaged/Eroded. Oroville Dam's Recently Reconstructed Main Spillway Fundamentally Flawed

They are boring holes next to the new blacktop road. I remember that this area was deeply excavated during the repair process. I believe they repaired the dam to weir junction at a deep level.

They could be installing test wells to see how much seepage intrusion there is? Just an idea

Highest precip reading in the basin is at Bucks lake: 0.76" so far from this storm today.

Picture of the manlifts under the gate structure

[link to pbs.twimg.com (secure)]

How did I find it then, fresh reboot and clean OS and IP?

More rain is on the way, too.

4pm readings:

Same as the 3pm ones. Same readings for the past three hours...

This is what I already said pages back to the person above... let me see if I can get these together

[link to imgur.com (secure)]

What could they be doing with the gates?

didn't know you had already posted...odd.

They have been trying to repair THAT.. They hope that will prevent blow out.. it won't.

Are they using those as jacks of some sort to put pressure on a failing or cracking section?

They don't appear to have buckets attached to lift anyone.

God help us if they are

Trying to open them.

Over the last 10 hours the reported increase in AF stored has been just 610 AF:

[link to cdec.water.ca.gov]

YET...if we calculate the difference between CFS inflows and CFS outflows during that same period, each hour by hour as follows:

OUT-------IN--Difference

9,522 10,668 +1146
9,448 10,417 +969
9,367 11,340 +1983
9,552 10,852 +1300
9,439 9,752 +313
9,591 9,752 +161
9,543 10,679 +1136
9,850 10,777 +927
9,724 9,660 -64
9,828 10,643 +825

That is an average hourly CFS differential of +869.6. That means a net increase of 869.6x60x60 cubic feet of water flowed in every hour for ten hours= 31,305,600 cubic feet added the past ten hours.

1 acre foot = 43,560 CF

31,305,600/43,560 = 719 acre feet (AF)

119 AF are thus leaking UNREPORTED, every ten hours, through other places...the main spillway gates, seeping under the spillway, etc... or about 12 acre feet per hour.

That's a LOT of leakage.

Depends...

That was tremendous. Hadn't seen that one.

If anybody thinks it might be out of date and not worth watching or listening, think again. The majority of it is very pertinent.

Two things that struck me.....

One is that Cahill says the gates are so bad they probably can't handle outflows higher than 40,000. Now Folsom dam had the same exact kind of radial Tainter gates, and the gate failed at 40,000. A big part of that was corroded trunnion pins.
[link to www.usbr.gov (secure)]

Oroville had the same kind of corrosion in the past and I don't know what got fixed. Maybe aging gates like this are not safe past 40,000?

The other thing was that Cahill said they should have closed up the gates and taken a chunk out the Emergency SW weir and rebuilt a brand new spillway there. The only way to make it safe. They had two years and maybe it could have been done, but too late now. It was an interesting part of the presentation.

A lot more, give it a listen.

Now we all watch and wait.

145 CFS is currently leaking, unreported, if the figures they are giving us are accurate.

So many great posts here. Thanks. It is mostly piping through the hill, correct?

So many great posts here. Thanks. It is mostly piping through the hill, correct?

That's what I was thinking, but those wouldn't support much pressure/weight.

Don't forget about evaporation.

Seriously?

Dear lord.

719 acre feet when you are talking 3,150,000 acre feet is like a few drops in bucket.

A wind shift in a lake that size will move the measuring gauge up or down more than that amount of water added into the lake.

The surface area of Oroville Lake at the level it is now is somewhat over 16,000 acres. Adding 719 acre feet of wter to that amount of surface area raises the lake by .0449 of a foot, or about 1/2 inch. (719/16,000 = .0449 .... 12" x .0449 = .54 of an inch)

Even on a small farm pond with NO WIND pushing water from one end of the pond to the other end I doubt you could accurately measure the lake level to 1/2 of an inch.

Hey science guys...

could this be the source of the vibrations? Not the water flowing down?

[link to www.catholic.org (secure)]

Today's modern Radial Gate designs have revealed a new and powerful force dynamic that was not well known years ago. Up to 60 ton Radial Gates have experienced a powerful "vibration" oscillation condition from critical flow levels in the gate openings. A standing wave of high and low pressure oscillation develops on the lower skin plates of the radial gate that transfers a complex set of distortions and movements to the massive steel gate structure. Indeed, experts are now attributing this powerful resonant oscillation vibration condition as a key component to the catastrophic failure of the Folsom Radial Tainter Gate in 1995 [11]. The power of this multi-mode form of oscillation in the massive trunnion gate structure would be dominant in forces applied to the Oroville Spillway Radial Gate design to these weakly coupled side seal assemblies.

EXACTLY! THAT'S WHY I LINKED IT UP LAST NIGHT.

I'M GLAD YOU ENJOYED IT!

Honestly I don’t take anything about this dam seriously because Only a Miracle is holding it together.

Yeah but if I understood the calculations, this is per hour. So at 1/2" per hour, that is a rise of over a foot a day. And this is with normal conditions. Now factor in the coming rainfall and the increased snow melt that will accompany...it's not an insignificant number.

I know a bad angle when I see one. The gate that is below the orange tarp above, that gate is leaning to the left.