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.

[janetjanet998]

confirmed now 2000cfs flowing out of power plant

I’m not sure if the seismic network will be able to detect the blasting, (it did at the rock quarry and has micro earthquakes as small as .4 the past few days on the map now)..

but none at the Dam so far

after mon-weds light-mod rain event(1/4 inch at DAM and 1-2 in mts) this mornings GFS model and other models from last night continue to build high pressure off the west coast causing the energy from future storms to be well north of CA....

(this pattern also means a very stormy pattern for the central and eastern US)

[EarthResearcher333]

"I assume that there is still some slippage of that wall even at these lower levels...the longer it runs the more it slips."

Simple Answer: On average, yes.

Subtleties: The "failing" of what is causing the "slip" is more complex and likely is different depending on the hydrostatic flow weight on the slab, rock, and tension of the slab anchor rods to rock securement. At 35,000 cfs the hydrostatic flow weight of the water is near 1.366 million lbs applied to the 50ft long by 178ft wide damaged chute section. At 50,000 cfs the weight is near 1.952 million lbs. A 30% increase in weight.

I suspect the key factor to the "slip" is the complex slab flexure, from this weight, that slightly bends open the myriad of micro cracks in the spillway. This determines the volume of pressurized water that is washing below in void areas under the concrete slabs. This erosion, pressurized water penetration into the fractured rock, and vertical pressure from the weight of the water on top of the chute slabs, will combine in a stress to the foundation of the damaged area.

The 30% difference in weight could make a notable difference in the "slight bending" and water penetration via the opening of the micro-cracks. Thus there could be a significant reduction in the rate of pressurized water penetration that is key in exacerbating (accelerates) the "slip" damage. This is called a non-linear relationship (curve).

** (178ft wide x 50ft slab x velocity x height), 62.458 lbs sq foot, equal linear flow (cross sectional w/ no differential velocities), flow velocity in ft/s from high speed video of 50 ft section @ 35,000 cfs.

[EarthResearcher333]

I dunno... KC Burke's secret high tech fix is out... they may implement this to ruin your estimate...

KC Burke's secret high technology "fix"

[mad_as_he$$]

lol..We’re gonna need a bigger - band aid.

[janetjanet998]

5 more pics just added to the DWR website...none of the main spillway or emergency spillway hillsides

saw a pic on another forum of some water(wet spots) running down the hillside of the shorcrete of the ES dated 4-14 from a KCRA helo shot ...could have been just rainwater runoff though

[EarthResearcher333]

Waterflow under Emergency Spillway? - Notable flow exiting emplaced Corrugated Steel Pipe - April 14

I've been waiting for a better "dry" day to get a capture of this water "underflow" behind the emergency spillway Weir from an earlier emplaced corrugated steel pipe. The outlet elevation of this pipe is 797ft. Reservoir levels were near 866 ft at the time of this image (April 14). Thus, given the amount of the observed seepage flow, this may be an indicator of a "piping source" or "sources" through the grout curtain under the Emergency spillway. The dried shotcrete contrasts well with this waterflow, revealing the extent of the amount of water collecting in this basin area underneath the shotcrete "armoring". (If this flow were to be from nearby ground water from percolation through soil, there would have to be a high saturation of the soil in the exposed hillsides in addition to the unusual flow angles necessary to reach the upslope inlet of the steel pipe). All indictors point to seepage from the reservoir & underneath the emergency spillway.

This is another inferred link to why DWR was conducting all of the core sample drilling in front of the Emergency Spillway - an investigation into "piping" which would answer the large air "bubbles" (reservoir side) observed shortly after the overflow of the Emergency Spillway.

Coring/Drilling in Front of Emergency Spillway - Most Likely Trying to Understand "This" (submerged flow paths - troubling "piping" under/through weathered rock & grout curtain)

Waterflow Seepage Under the Emergency Spillway Armoring at elev 797ft - Potential "piping" from the reservoir side

[janetjanet998]

That is about where the underground pipe was under the old roadway before the ES was used i think

Could it just be rainfall water the collected on the opposite side of the rebuilt road hidden from view draining off?

If rain hits the ES ledge it would drain off it and perhaps get dammed up behind the road in that low spot..so perhaps they put a drainage pipe under that road????

[janetjanet998]

well disregarded previous post
there might not be much of a low spot anymore

your 4-15 pic
http://www.freerepublic.com/focus/f-news/3524221/posts?page=3138#3138

[EarthResearcher333]

Hi janetjanet998, they armored the full basin at the road just behind the ES Weir spillway. There are no dark streaks or dark areas showing a water pooling or collection (to go to a "pipe"). If they were to place a pipe that allows water penetration from an Emergency Spillway Overflow, this penetration could be a weak point (pipe)- if it fails. Installing a pipe in the upstream road bank risks allowing an erosion flow underneath the shotcrete armoring, thus creating an erosion collapse via voiding under the armoring. This failure could defeat a large section of the armoring fairly quickly, leading to a "back head cutting" failure mode that caused the emergency evacuation of 188,000 people. A fully armored basin at the road will force waterflow to topple over the road, thus indirectly acting as an energy dissipator. note: I could be wrong, but if someone decided to insert a "failure" source into all of that expensive rock emplacement and shotcrete blanketing, someone should be "shotcreted"…

Note: (KC Burke) - the video shows the trucks creeping very very slowly, only one at a time & centered on the spillway bridge. Notice the other trucks are waiting for their turn to cross. That bridge has to have been enduring a significant load flexure repeated stressing from all of the heavy loads of rock, concrete trucks, etc during this whole crisis. This pic gave me a chance to point out (image) what I had mentioned upthread on the bridge.

[EarthResearcher333]

Yes, that picture shows it best (full sealing & no dark streaks from pooling).

[KC Burke]

It’s so super strong from being doubled that I can’t imagine it won’t be as big a success as some of the other measures utilized.

[KC Burke]

That corrugated pipe could have been placed there under a condition as follows. There was a “wet area” that was not removed but was not dry when the gunite was placed and they placed a pipe as a “weep”.

Now, I would have just dug out the wet material, but the pipe obviously is there for some dang reason.

[EarthResearcher333]

Water Seepage from Emergency Spillway "Weathered Rock" - Weir "Box" Drains designed for seepage to flow under rock+shotcrete "Armoring"

More Discussion: DWR photo reveals seepage from openface "weathered rock" at the end footing junction of the large Concrete Weir. Half pipe material placed around "Box" drain outlets of Emergency Spillway inferred to protect from being sealed by the shotcrete process. Photo shows the spaced "box" drain outlet locations (where the half pipe material protrudes above the shotcrete finish level.

The Large Concrete "Gravity Ogee Weir" has horizontal drain channels along the length of the center of the Weir (see blueprints). These channels connect at junctions to the outgoing channel "box drains". The drains were designed using wood planks, forming a box "void" channel upwards from the surface of the base rock. This original construction approach was used to accommodate the uneven rock surface. Hand placed concrete stabilized the wooden shapes before the large pour of the main solid concrete Weir. The design incorporated a horizontal drain collection near the center (bottom) of the Weir which the box drain outlets would intersect and allow any footing collected seepage to outflow via these outlets.

After full armoring in "emergency repair" of the lower footing of the Large Gravity Ogee Weir was completed, wood forms were built around the weathered rock abutment for concrete "walling" of the face. An April 3 DWR photo reveals construction workers concrete sealing the full face of the weathered rock "hill" abutment. Photo also reveals a persistent flow of seepage that left a residual orange mineral colored sediment flow pattern on the shotcrete. The source of this "seepage" is at the junction of the Ogee Weir abutment to the reddish/orange weathered rock. DWR has discovered that the large concrete weir is not anchored to the base rock footing (assumed "weathered rock" base). This is in contrast with HYD-510 Hydraulics study blueprints denoting a solid "keying" protrusion into the rock in their Weir design drawings. This "keying" protrusion is a method to anchor the Weir into the rock to resist against lateral forces. As constructed, the Weir is simply sitting flat upon a bench of rock footing - as also denoted in the main blueprints. This "non anchoring" flaw is why DWR's new concept drawing has heavy "Buttressing" layers of RCC on the backside of the Weir.

(1) The strategic placement of the Steel Corrugated Pipe, at a low basin point & downslope to a flow channel center, infers an intent to transfer any underflow of water to the gunite shotcrete armoring surface. (2) Images reveal there are no "dark area" waterflow inlets upslope to the pipe (i.e. shotcrete bright & dry). (3) A collection of all of the inferred evidence only establishes the attention to facilitate any seepage from the Weir drains underneath the large rocks (base) with gunite shotcrete overtop layering. (4) IF the box drain flows, along all of the footings of the length of the Weir, are reflective of the seepage at the Weir abutment, there could be a notable seepage that could collect in a basin area in the weathered rock. (5) There is evidence of potential "piping" revealed by the "bubbling" episode on the reservoir side of the Emergency Spillway. This demonstrates a porosity of the general area in and around the Ogee Weir.

Another consideration is that the "armoring" is not completely without small cracks. Rainfall could collect & provide a subsurface water source. However, the noted waterflow of the drain should correspond to puddles and wet areas of the shotcrete. At the time of the photo, the apron was bright and dry with no dark areas.

Just another puzzle- but (1)-(5) point to a degraded sealing (grout curtain) of the Emergency Spillway linear zone of rock. How it gets from point A to B only H2O knows.

note: Original construction archives resolved a question on the aggregate vs concrete blueprint markings of tiny rock illustration. The Weir is solid concrete with a 4 ft outer shell of enriched concrete. A prior thread posting (mine) is incorrect on the discussion notation of "aggregate" only filled shell.

Solid Concrete Gravity Ogee Weir with bottom drain design. Weir is not anchored. DWR's new concept design addresses this flaw with heavy buttressing of RCC concrete. HYD-510 design had a "key" to anchor - DWR's blueprint design did not incorporate this "key" in the footing (introduced a "flaw").

"Box" drain formed out of 3 wood planks (bottom has "spacer" wood pieces). This drain design accommodated the rough rock surface.

Half pipe material emplaced at "box" drain outlets to protect these drains from being sealed by gunite shotcrete armoring (emergency repairs to armor ES). Box drain seepage flow enters beneath the large rock & aggregate base. Note seepage at the junction of Weir footing and weathered rock face.

Notable seepage orange residue flow path left on shotcrete surface - originating at the footing of the abutment of the Weir and weathered rock. Construction workers sealing the face of the weathered rock via concrete filling in a wood form wall around the face.

[EarthResearcher333]

No Specs for Rebar in Solid Concrete Gravity Ogee Weir - Water from tiered slab pour show leakage via crack/seams when reservoir is high

Perhaps another reason for the RCC Buttressing in the New Concept design for the Emergency Spillway Repair is to address a design issue "flaw" to protect against "shear fracture". Throughout all of the construction blueprints, construction archive pour descriptions, the Hydraulic Study HYD-510 report, there are no markings or descriptions of any "mesh" or "rebar" within the "Solid Concrete" Ogee Weir. There already is a known "flaw" to the Weir in that it is not anchored. Images reveal that water is leaking in linear sections at the crack/seam pour layer locations on the large concrete Weir. note: These linear leaking seams are at or below the reservoir level at that time. This infers that longitudinal cracks are present in the solid pour concrete such that water is penetrating through the concrete via crack/seams. IF there is no metal re-inforcement emplaced within the original pour of the Emergency Spillway Weir, there is a risk of shear fracturing in the case of a seismic event. A lesser risk, but still real, is the head pressure & flow shear force of a high reservoir level & flood level flow. The "anchoring" flaw + the likely "shear fracture" issue, from non reinforcement metal, is a good basis in reasoning as to why the New Concept Emergency Spillway Design incorporates a large RCC Buttress layer on the backside of the Ogee Weir. In fact, DWR's new design report stated: "This is common to dam engineering an normally referred to as buttressing the dam to ensure the structural integrity of the weir under flood flows and future possible seismic loading conditions."

Essentially, from a different perspective, DWR's new design is fixing these flaws (anchoring flaw & shear fracture flaw) without fully pointing out these "flaws" in the report (even though "flood flow" & "seismic" are both noted in the statement).

Water is leaking via the linear crack/seams from the tiered slab pour of the Large Gravity Ogee Weir. Note the reservoir - seam/crack water leakage at or below the reservoir water level. No rebar or mesh found in any of the myriad of archive documents. Likely just solid concrete w/ no rebar or mesh.

New Concept Design incorporates an "RCC Buttress". Note the height of the buttress. Goes to the upper layers of the Weir. This buttress "fix" covers the anchoring "flaw" and evidence/documentation inferred "flaw" of shear fracture risk of the concrete Weir.

[KC Burke]

Note the height of the buttress. Goes to the upper layers of the Weir. This buttress "fix" covers the anchoring "flaw" and evidence/documentation inferred "flaw" of shear fracture risk of the concrete Weir.

I agree. It just piles a massive Roller Compacted Concrete mass against a flawed weir in an effort to make a combined structure of such magnitude that its occasional use under extreme flood will be infrequent enough that the combined mass structure will stand up to a temporary mass flow during a flood event.

The drain leaks in the sink. We will add a flat plastic stopper on top of the leaking stopper, add a heavy skillet at the center of the pile of dirty dishes and make it full of soapy water, all to make the drain hold long enough to wash the Christmas dishes. We never fill the sink this full because the whole family only comes over once a year.

It is simply too much effort and time in this old kitchen to get under the sink and tear out the corroded drain and redo all the plumbing in time for Christmas dinner -- its Christmas Eve tomorrow.

[Ray76]

The weir was full of water.

They dodged a BIG bullet.

[EarthResearcher333]

I agree.

[Ray76]

That sums it up perfectly.

[abb]

From over on Metabunk

https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-41#post-205116

Dan Brekke
New Member

Boilermaker said: #8593

...Maybe the only item of interest in this is that the DWR spokesperson repeats the comment made by Mr Croyle two press briefings ago that there was a lot more concrete used than the original construction specs refer to. She said that this was in the area of the spillway “core” without saying (or being asked) where that is. I’ve taken this to refer to backfill on the rock surface under the deck but if so a lot of it must have got washed away.

I asked DWR the week before last to expand on the claim about the thicker concrete. Here’s part of an email exchange with the person who’s been put in charge of responding to most spillway questions:

Q. Director Croyle mentioned that drilling on the upper spillway has revealed areas with 4 or 5 feet of concrete. How extensive are those areas? Earlier reports from Board of Consultants and others stated the slab was 9 to 15 inches thick (depending on placement of sub-slab herringbone drains). Were those reports essentially accurate?

A. A number of holes have been drilled in the upper portion of the gated flood control spillway and more will be drilled in order to assess geological conditions. Some bore holes show concrete that is four to five feet thick, some do not.

And that’s all the department’s communications apparatus chooses to say on that subject. I don’t know if you could be less informative if you tried, but I’m guessing that’s precisely the department’s intention. It would be easier if they’d just say “take our word for it.”

Dan Brekke, 24 minutes ago

[EarthResearcher333]

Quick answer to this posturing (i.e. Thick concrete) is: So, if you're saying there are "thick" sections, inferring, something "good" or "better", then why is it there are drain cracks in every single slab in nearly every single drain run for the full length of the upper spillway? OR for that matter, the entire spillway?

Are you now inferring you have "rotten concrete" just like the "rotten rock"?