Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[EarthResearcher333]

I believe the problem is bigger. Notice how "green" the grass is further up past the electrical tower. Now compare this to the greenest of green grass on the other hillside on the other side of the spillway. Unless the soils are richer on the left side, the darker green grass on the left side (far upslope) indicates a widespread saturation of the slope. At a certain elevation point, the spillway flow cannot get to this high (water table).

An unconfirmed report - many posts ago - was heard on the radio chatter of a crack in the gate roadway, and that there was water seepage coming out of the crack. I surmised - if the report was legit - that the location was on the ES side of the curve part of this bridge road. IF so, this crack would have been at an elevation in the hillside of the left side of the spillway (looking upslope). This may be a clue if there is a potential "piping" source at or beside the gates.

[EarthResearcher333]

Longitudinal Underdrain revealed: Conflicts with blueprint design - actual location fits with ability to connect to herring bone underslab drains

This is for the engineers: Regarding the "longitudinal" connecting sidewall drain pipe location: There had been discussion of what the original blueprint designs illustrated verses what the actual design was constructed as. This photo reveals that the longitudinal drain is beneath the lower part of the sidewall footing. This allows the herringbone pattern of underslab drains to connect in coupling joints to this "collector pipe". Each "collector pipe" will have a number of underdrains feeding captured water under the slabs (except for the "underflow" design flaw that channels down the spillway creating "washing voids").

Wet spots in the hillside soil infer water escape flows from (1) the upper hillside level (2) from the "underflow" design flaw of "uncaptured" water channelling down underneath the spillway. Water streaks area also observable on the edges of the sidewall footing. This too is from the same "escape" flow(s) mechanism.

Longitudinal side drain reveals actual construction design - conflicts with the design blueprints (blueprint design flawed in that it would force a complex coupling system with a "gravity jump point" + a sediment collection issue (i.e. not fully self-cleaning in the "upward joint/bend)

[abb]

I’m not sure the collection pipe turns up at the sidewall drain. That pic’s perspective isn’t true horizontal. I suspect (but do not know until we see as built dwgs) that the collection drains are pitched slightly below horizontal and then connect to the elbow at the wall.

The independent drain systems would have to overlap in the vertical plane to serve all the longitudinal (herringbone) drains.

I sure wish they’d come across with the drawings.

[janetjanet998]

could the wet arers just be from all the splashing when they decreased the flows?

[janetjanet998]

never minds just saw post 2797..wow

[meyer]

Flow through the Hyatt plant appears to have been bumped up a bit, to around the 13,000 cfs level.

[EarthResearcher333]

Not sure what the confusion is about. Even your original sketch (post 2094) identifies & agrees that there must be two overlapping sidewall drain pipes ** (one at the footing - "collector" and one heading to the next sidewall drain "elbow").

Had this discussion before (where you agreed post 2355) in where post 2,354 reveals the "optical illusion" of the true slope of the broken drain (see link - it shows a downslope at/near -2.5 degrees from horizontal).

** Took your original image and modified it: The green pipe "fix" is connected as a "erosion bypass repair" to a 12" drain that had been interconnected with the broken coupling elbow in the sidewall. The interconnection piping to the sidewall elbow is missing from the erosion and spillway chute fracturing.

The newly revealed "other" 12" sidewall longitudinal drain revealed itself after the recent spillway run as it facilitated erosion of debris that covered it prior. Perhaps there is a misunderstanding in thinking this "footing" drain was stated as connecting to the elbow above. This would be incorrect as the slope angle to this "footing" drain would have been positive (i.e. non-gravitational "flow" oriented). What the picture reveals is the natural "overlap" of sidewall drain piping. At some point, this longitudinal footing "collection" drain has a coupling that angles piping towards its next sidewall elbow drain outlet. The destroyed section further down the spillway is where this transition would occur (if not at the junction of the outline of the herringbone drain @ the broken edge of the main spillway).

For the Curious: an Optical illusion - Gravity Drain Pipe design flows downward..

Abb: I think you have it about right. It clarifies that manual iso layout sketch I posted upthread.

Abb's original sketch re: under slab drainage design..

Updated/modified sketch to illustrate what is in the image (prior discussion)

[abb]

Yes, that’s it. LOL, I’m gonna have to break out my old drawing desk and giant 30/60 and try to recreate the thing to scale. Autocad came along just about the time I gave up drawing for a living and went into sales and estimating.

The only thing I’m not seeing is where there could be a part of the piping that’s tilted above horizontal and could trap sediment.

[EarthResearcher333]

Flawed Drain design of original blueprints: Corrected in construction..

Hi Abb, This. The original blueprint design had the collector drains located at the top of the sidewall footer. If constructed this way, the underslab drains would have had to connect to this topside footer drain through an "upwards" coupling. This is where there would be a problem with a "self-cleaning" full gravity flow design.

You got it right in your drawings on the actual construction architecture (with a tweak of angling the underdrains to be "herringbone" patterned). :-)

Flawed Drain design of original blueprints: Built differently from blueprints in actual construction. (Abb was correct).

[Repeal The 17th]

How would this be done today with updated knowledge/technology?

[abb]

My $0.02 opinion is that the slab should be constructed to prevent as much water infiltration as possible. Joints should be properly spaced to allow for initial shrinkage during concrete curing, and subsequent heating/cooling movement. This would minimize random, unplanned cracking.

The joints MUST be properly sealed. And then the joints MUST be inspected for sealant deterioration and promptly repaired.

Whether this can be done to a sufficient degree to make a drainage system unnecessary, I don’t know.

[Repeal The 17th]

Still no updates to the pictures since ‘Bambi’.
https://pixel-ca-dwr.photoshelter.com/galleries/C0000OxvlgXg3yfg/G00003YCcmDTx48Y/Oroville-Spillway-Damage

[Mr. K]

diversity training

[EarthResearcher333]

"How would this be done today with updated knowledge/technology?"

I'm assuming you're asking about the drains...

The FRpost link below provides modern design technology based on spillway design history and failure knowledge gained. Oroville's main flaw was in designing the drain "within" the slab, thus forming thinning zones (and severe slab cracking in the drain pipe zones). Aggravating this was that the slab design had no bottom rebar reinforcement, which affected the flexure resistance. Modern designs incorporate a superior "water stop" system to minimize water penetration at the expansion joint seams of the concrete slabs. What is not shown in the FRpost modern design drawing is the same type of downslope "collector" drains. This would be the same as done in the Oroville design (gravity flow collectors to sidewall outlet drains).

note: the worst case 40% thinning reference has been found to be up to 60% thinning due to the bell coupling dimensions + the 6" VCP pipe upsizing from the original spec 4" VCP pipe blueprint drawings. The Board Of Consultants have confirmed the "thinning" problem (but did not go into further specifics - likely a hot topic structural design flaw if revealed to the press/public).

Modern Spillway Design vs Oroville Design - 2 Dam Failures, Drain Pipe, Rebar, "Hydraulic Jacking", "Void" Finding by Radar

[EarthResearcher333]

= = Off topic note: = =

My posting updates may become sporadic. Another heart arrhythmia condition is recurring and may require a new operation (after a history of multiple ablations). I apologize if I am unable to respond to queries in a timely manner.

[Repeal The 17th]

Thanks!

[Repeal The 17th]

Take care of yourself.
I’ll offer up a prayer.

[mad_as_he$$]

Health first! We will be here when you get back(but we will miss you).

[mad_as_he$$]

For next Friday and into the following weekend, it is likely that
the AR will finally move into the West Coast. Current forecasts
favor the Pacific Northwest; however, intensity and especially
latitude are still in the realm of lower predictability with the
main question revolving around how far south the moisture and jet
stream drop. Increased chances are not a guarantee, but definitely
worth keeping an eye on as a direct hit from another AR would
again increase flooding concerns in the region. Snyder/Tolby

http://www.wrh.noaa.gov/total_forecast/getprod.php?prod=XXXAFDREV&wfo=REV

[Jim W N]

I hope and pray for the best for you.

Thanks for your thorough analysis. Dunno who can step in while you’re gone. Anyway, hope all goes well.