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]

Hi KC Burke, Here is a pic that caught my eye regarding "swirls". Reminded me of the finisher machines. I haven't searched through all of the pics to see what equipment they are using. Besides the "swirl" patterns, the fact that the finish layer was below the form peak edges also caught my eye.

This means some level of expertise & technique (equipment) was being applied to assure a level (with respect to downslope "level") surface was consistent inside this form.

I also thought I saw that "side-by-side" slabs had a gap between them. I suspect this "gap" is for another pour to where the "water stops" will be in place as a single strip pour with a divider gap material will separate the junction of the two slabs.

"Swirl finish pattern" on the surface of the new slab. Zoom picture - requires good display to discern.

[EarthResearcher333]

Sub Drain Design revealed. Filter Gravel surrounds a large plastic pipe. Tape strips (temporary) covers the pipe end. Wasn't able to discern any drain holes in the lower part of the exposed pipe.

This image, with the shovel as a reference, reveals the large size of the epoxy coated steel anchor bar, plates, and nut. A sizable increase from the original spillway design.

[KC Burke]

The way I view that pic, the sub drain is in the mud slab or rock base entirely below the slab itself thereby causing no slab thinning, the feature of the old spillway I found totally non-standard for any sub-drain months ago.

[Ray76]

Vertical rebar panels are put in place to reinforce the new concrete walls on the upper chute of the Lake Oroville flood control spillway in Butte County, California. Photo taken August 7, 2017.

[EarthResearcher333]

How Good - or Bad - is using a Toe Drain to detect Dam Anomalies? (When you don't have any working piezometers in the dam)

This will be a series of posts in discussing this question as DWR has zero working (non-useful) piezometers** in Oroville Dam. All of the array of these very important instrument sensors have been allowed to expire in usefulness without replacements. Thus, this issue directly relates to the Green Spot discussion as a decision was eventually made to use the Dam's Toe drain seepage as an "anomaly detector" to any internal issues with the dam. FERC has repeatedly asked DWR that they be able to measure the internal water levels (Phreatic level) and conditions (Phreatic condition) internal to the dam (translation, please install piezometers).

Since DWR hasn't followed FERC's requests, the only "trigger" detector to any internal dam problem, such as leakage increases or changes, is anticipated to be caught by the toe drain pipe at the bottom of the dam (downstream "Toe" of the Dam).

A Cross section side view of Oroville Dam is shown in Fig 1. Orange & Brown colored vertical sections are designed to work together to retain the reservoir water. A Clay/Clayey Core (orange) is the plastic material that is the most waterproof. But this highly compacted material requires stability support as it can bend or arc without a "sandwich" type of side compressive support. The Brown layers next to the core are called the Transition zones where they provide an immediate abutting mechanical stability/support with the ultimate help of the massive Zone 3 outer zones/layers. The transition (Zone 2) layers also perform an important function of (1) maintaining a soil particle/materials "compatibility" between the Core and the Zone 3 different compositions and (2) the Zone 2 layer can "heal" any imperfection cracks in the clay/clayey core by allowing silts/sands within the Zone 2 layer to migrate into the Core if a small crack (leak) develops. Migrating materials to seal these cracks are carried by the leakage water. Note: The upstream Zone 2 layer provides most/all of (2) as the water pressure & flow is upstream to downstream (left to right in image).

Even a near perfect Earthen dam will leak given a very large surface area. A process of high water pressure differential causes a slow migration of moisture between the tiny grains of the Core and Zone 2 layers - even though the tiny grains remain in place. This is considered normal seepage through the core.

To maintain the structural integrity of the downstream massive Zone 3 "sandwich" layer, it is important to keep the Zone 3 layer from becoming saturated, -or- keep it in a somewhat "dry" state. This is accomplished by making the Zone 3 layer such that water can migrate through it by incorporating "voids" into the materials. Thus the smallest material mixed within is sand (in combination with Boulders, cobbles, rocks, and gravels). Rainfall thus will migrate as shown in the light blue arrows in Fig 1.

The other key to keeping the Zone 3 layer from being saturated is in using a "Vertical Drain Chimney" of Boulders, cobbles, rocks, gravels (20 feet thick - all along the backside of Zone 2) that allows any normal seepage from the Core & Zone 2 layers to be drained into this chimney down to the secondary part of the drain - the horizontal drain zone (10 feet thick). See the dark blue arrows in Fig 1 for the ideal (non clogged) flows.

At the lower right hand side of Fig 1 is where all of this collected seepage (through the core and rainfall) would be trapped in a mini "barrier dam" and a 30 inch RCP pipe (Reinforced Concrete Pipe) would transmit this "seepage" flow to a meter station where flows are measured in gallons per minute (gpm).

Keep in mind that ANY seepage, core or rainfall, relies on the left and right canyon abutments (canyon walls) to help "channel" this flow towards the narrow horizontal drain channel at the bottom (near the "v" bottom in the canyon). This "horizontal" drain channel is not much wider than the original Feather River channel width (at bottom). See post 4,117, Fig 1.

To "detect" any internal problems with leakage in the dam by using the "Toe Drain" seepage flows requires an understanding of all of the possible internal dam issues that could affect this flow - such that may introduce errors in interpretation.

Over the years, The Division of Safety of Dams (DSOD), DWR, & O&M, should have records of the Toe Drain seepage flows in known reservoir levels and rainfall conditions. If a good history of measurements were conducted consistently over the years, a "profile" of expected performance could be compared against.

NOTE: DWR is using both the Toe Drain seepage and the Right and Left Gallery drain seepage channels to form a "sense of health" of the dam. For this discussion (Green Spot), only the Toe Drain is the point of focus (gallery drains are mainly "core" and Zone 2 canyon wall side abutment seepages from the reservoir and or "springs" at these tunnel locations).

(**Piezometer = sensor, detects water presence and water pore pressure levels).

Fig 1. Cross section side view of Oroville Dam. Orange & Brown colored vertical sections are designed to work together to retain the reservoir water.

[abb]

Obliquely related to our issue here, I think. Bureaucrats lie in Louisiana, too.

http://www.theadvocate.com/new_orleans/news/politics/article_54ba059c-7c8a-11e7-b749-6719f4973a1f.html

New Orleans flood fallout: Officials lose jobs; revelation of inoperable pumps ‘insulting to the public’

JEFF ADELSON | jadelson@theadvocate.com
8/8/17 - 8:30 PM

Pumping stations serving the two New Orleans neighborhoods hit hardest by Saturday’s flood were operating at barely above half their full capacity, officials admitted Tuesday, directly contradicting assurances offered earlier by the Sewerage & Water Board and leading Mayor Mitch Landrieu to purge several top city officials.

The acknowledgement that critical portions of the mammoth system of pumps and canals intended to deal with heavy rainfall were down, pulled from S&WB officials during hours of testimony before the City Council on Tuesday afternoon, came after the agency had spent three days telling residents the pumps were operating to their fullest extent.

Cedric Grant, one of Mayor Mitch Landrieu’s highest-ranking deputies and the head of the Sewerage & Water Board, said he would retire at the end of hurricane season this fall, admitting that the public had lost confidence in his agency.

Public Works Director Mark Jernigan, who came under fire amid questions about whether his agency had done enough to clean the catch basins that feed the drainage system, submitted his resignation shortly after testifying to the City Council.

Landrieu said he would ask members of the S&WB this week to fire two other high-ranking officials, including the agency’s general superintendent, Joe Becker.

Not seeing the video below? Click here.

The flooding in New Orleans on Saturday happened even though the drainage system was working…

Dani Galloway will become acting director of public works. Landrieu suggested that Robert Miller could take the helm at the S&WB after Grant’s departure.

During a grueling interrogation by City Council members at a public hearing, Becker was forced to withdraw repeated assertions that the city’s drainage pumps were operating at “full capacity” as the water rose Saturday. He acknowledged instead that the pumps were operating at the “capacity they had available to them,” drawing laughs and catcalls in a packed council chamber.

As it turned out, pumping stations in the hardest-hit areas of the city had lost more than a third of their capacity as a result of repairs and maintenance work. And issues traced back to the S&WB’s power plant on South Claiborne Avenue meant the pumps had to rely on Entergy for power, requiring power to be rationed in a way that cut further into the ability to move water through the complicated drainage system.

Overall, it took 14 hours to fully dry out the city from rainfall that ranged between 1 and 10 inches at various locations.

The drainage system is designed to handle 1 inch of rain in the first hour and a half-inch each hour after that.

Becker, at times visibly pained by comments from angry residents behind him, insisted that the system would need to be hugely expanded to handle the amount of rain that fell Saturday without any flooding.

His comments did not satisfy council members, who clearly felt the answers they were getting were evasive if not downright false.

“If I didn’t follow up with you, I might have thought that less than a third (of capacity) was lost,” Councilman James Gray told Becker at one point. “The way my parents raised me, once they caught me not telling the truth, they didn’t believe anything I said.”

It was an unusually assertive display of anger from council members, and an embarrassing episode for Landrieu, who has sought during more than seven years in office to project an image of competence and sure-footedness in a crisis.

He has rarely criticized the work of his own staff, but he said during a news conference after Tuesday’s hearing that Becker had “danced around” the council’s questions.

While watching New Orleans Councilman James Gray’s growing exasperation as he grilled Sewera…

“The obfuscation we saw today, it’s insulting to the public,” Landrieu said. “Being open, honest and truthful is critically important.”

Although he has fired other officials, Landrieu’s administration has generally been very stable, and this purge was unlike anything seen in the first seven years of his tenure. He leaves office in nine months.

Beyond the resignations and firings, Landrieu said he has called for a full report from city officials on the response to the flooding as well as a third-party analysis of exactly what happened on Saturday and how that may have affected the amount and duration of the flooding.

Throughout his comments, Landrieu made clear that deception was the main issue in the terminations, repeatedly returning to the idea that “Mother Nature overwhelmed parts of our system” and that even at peak performance, the drainage system could not have prevented all the flooding.

That’s largely been the opinion of other experts as well, including meteorologists and outside agencies. More than 9 inches of rain was dumped on Mid-City in about four hours, nearly four times the amount the drainage system could handle in that time.

“In order to build a pumping system that would clear it out in three hours would cost a gargantuan amount of money. I can’t even imagine how much,” Landrieu said.

During the hearing, frustration built as council members interrogated Becker over which pumps were offline and how much pumping capacity was lost as a result. The picture that emerged was significantly different from what officials had portrayed over the weekend. Even so, it remained unclear how much flooding could have been prevented or mitigated by a fully operational system.

Over the weekend, Grant and other officials said publicly that the pumps were working at full capacity. Then on Monday, Becker told the media that while seven of the city’s 121 pumps were out of service for maintenance, that did not affect how much water the agency could move out of the city within a given time.

On Tuesday, Becker finally acknowledged that 20 pumps were inoperable, though he said the extra dozen were low-capacity pumps typically used to move runoff when the bigger pumps aren’t needed.

What proved explosive, however, was the revelation that some of the out-of-service pumps were in Mid-City and Lakeview and that they represented a big chunk of overall capacity in those hard-hit neighborhoods. In Lakeview, capacity at one point dropped to 52 percent because of the electrical issues.

In Mid-City, the pumps operated throughout the storm at about 63 percent of their total capacity. Other issues also caused one additional pump to go down for 20 minutes, though it was not clear exactly what impact that had on the overall amount of water pumped through that station.

The details came out only after extended questioning from council members.

Gray, in particular, had a change of heart over the course of the frustrating exchanges. He said that he initially was sympathetic to Grant, in particular after hearing shortly before the meeting began that he would retire.

Gray suggested he had thought some concerns expressed by many members of the public were overblown but those sentiments evaporated as he sought to pull information from Becker.

“I thought we were on a witch hunt, but I feel like we found witches,” Gray said.

Landrieu spokesman Tyronne Walker said the mayor’s office became aware of the extent of the problems late Monday, after Landrieu got back in town from a weekend trip to Aspen, Colorado. Walker said the mayor’s office asked the S&WB for the logs from the pumps and realized “there were more pumps down than we had known.”

Sometime Monday evening, Grant also began discussing the possibility of his retirement as executive director of the S&WB and overall coordinator of all city infrastructure projects.

The pumping problems were among a litany of complaints raised by council members about the flood.

Some criticized the city’s Office of Homeland Security and Emergency Preparedness for waiting until the National Weather Service put out a flash flood warning to alert residents to the danger, even though 911 had received calls about flooding a half-hour earlier.

Others focused their ire on Jernigan and the Department of Public Works for failing to clean catch basins efficiently, which can keep water from getting into the drainage system in the first place. And more concerns were raised when it came out that the S&WB had not just misled the public but failed to notify the Emergency Preparedness office that not all pumps could be turned on.

Other concerns were raised about the lack of barricades to prevent cars from driving into flooded areas.

“Before we talk about spending an extra penny, we want to make sure that every dime we’ve spent so far is being used adequately,” Councilman Jason Williams said. “People are angry. They feel like they haven’t gotten answers. It doesn’t make anything better to hear that things are working when things are not working.”

The entire episode could have a major impact on the quasi-independent S&WB, though exactly what will happen to the agency is unclear.

Grant has been a pillar of the administration since the beginning of Landrieu’s first term in 2010, when he was appointed deputy mayor overseeing all capital and infrastructure projects.

Then, when the former head of the S&WB retired, Grant, with Landrieu’s backing, became the head of that agency while still keeping his infrastructure role, an attempt to better coordinate the work of two departments focused on construction. At the same time, changes were made to the membership of the civilian board that oversees the S&WB.

Tuesday’s revelations, and the overall lack of trust in the agency, could serve as a catalyst for a further overhaul.

When asked whether he would seek any changes to the S&WB’s governance or seek to align it even closer to City Hall, Landrieu said, “I think the board and the City Council are going to have to think through that. Everything should be on the table.”

[EarthResearcher333]

Sad. Painful for people in flooding damage (homes, cars, keepsakes, cost).

[abb]

There’s an election coming up. That’s the only time politicians get scared.

[EarthResearcher333]

DWR tells another Whopper? Reporter corners DWR on FERC PFMA on Spillway - DWR says full spillway was built on "good competent rock"

A nearly Unbelievable Answer from DWR: Reporter Dan Brekke at KQED news is on a roll. Corners DWR & DWR responded with what only can be categorized as a "whopper". This is beginning to feel like the saga of what the definition of "is" "is".

Erin Mellon (spokesperson for DWR) stated that historical documents of geologic studies, included in a Potential Failure Mode Analysis (PFMA) in 2014, were looked at and it was concluded by this evidence that the Spillway rock beneath it was extremely competent.

This now has to be the biggest provable "whopper" from DWR to date. The reporter tried to contact the four consultants that did this PFMA of the main spillway breaking and then the Emergency Spillway dangerously eroding, but these consultants did not respond back (no surprise?).

Here is the "Whopper" and why it is such. DWR's own historical Final Geology Report Spec 65-09 documents a massive seam of clay/clayey foundation (intensely weathered rock = hard clay) EXACTLY starting at the blowout failure area (and going upslope to the point of the upper spillway remains). Below is a picture of this from their own report. Prof Robert Bea & the team of contributors documented this in the July 20 Failure Analysis Report. (picture is from Appendix B, Fig B.21).

Erin Mellon must be unaware that even the DWR Field engineers told contractors NOT to excavate down to hard competent rock - that they felt the contractors were trying to get extra $'s by backfilling concrete at $30 cu/yd. Told the contractors to dig only "to grade". (See Fig B.17 below)

Erin Mellon must be unaware that DWR Field engineer's orders meant that the Final Geology Report's noting of massive clay seam areas were left "as-is" as identified by the Final Geology Report Spec 65-09. (See Fig B.21 below)

Erin Mellon must be unaware that DWR anticipated in placing anchor bars in clay seams as they tested the bars in clay to test in "the worst foundation available". (See Fig B.20 below)

Erin Mellon must be unaware that the "blowout failure" of the Main spillway occurred EXACTLY at the seam boundary of this clay/clayey foundation (i.e. "worst foundation available" as noted by DWR's Final Construction Report 65-09 - Fig B.20). Blowout - see Fig. B.10.

I certainly hope the Forensic Team picks up on what is being said. If not, they could be caught up in this extreme dichotomy of truths, non-truths, fact, and fiction.

Note: Much more in Dan Brekke's article - read the full story at the link (only one main issue brought up in this post).

= = Article Clip: (Whopper by DWR's spokesperson) (emphasis mine):

"Department of Water Resources spokeswoman Erin Mellon said in an email Monday the evidence presented for the potential failure mode analysis included a site inspection and historical documents including past geologic studies of the area." "While not offering specifics about the data considered, Mellon said “the information gathered showed the spillway was in good condition and the rock beneath it was extremely competent.”

= = end clips More at Link:

Panel Weighed Oroville Spillway Failure in 2014 - and Called It Unlikely

https://ww2.kqed.org/news/2017/08/09/oroville-dam-spillway-ferc-safety-review-2014-ruled-out-spillway-failure/

Professor Robert Bea CCRM et al Final Report link (team of 14 contributors): sections above from Appendix B:

https://drive.google.com/open?id=0Bz1I1mIutSEnbFJuVUJZWWNNVlU

Fig. B.21. DWR Final Geology Report Spec 65-09 denotes the foundation geology of the subgrade quality of foundation material that the invert concrete chute was constructed upon. The Seam (marked as a series of "S"'s) follows the dashed line seam in Fig. B.10. This drawing reveals the same foundation structural integrity transition region of the quality of the foundation material as in the blowout failure erosion images in Fig. B.10 and Fig. B.11. This geologic report drawing identifies that DWR was aware of the type of foundation material at this future blowout location. DWR BOC report Memorandum No. 1 notes that "Compacted clay is also a term sometimes used to describe highly weathered rock."

Fig. B.17. Dispute arose between original specifications intended to excavate the spillway to strong fresh rock or strong weathered rock. Specification stated: "Excavation for the chute shall be to fresh or moderately weathered rock that cannot be further removed by heavy duty power excavating equipment." DWR Field Engineer intervened and directed the contractor to only "excavate to the grades shown on the drawings". The contractor was following specifications to where any poor foundation material would be backfilled with concrete to "grade level".

This report statement infers that DWR believed the contractor was using this specification in a desire for the additional pay of $30 per cubic yard of concrete in backfill work. This DWR Field Engineer intervention "orders", in contrast to the accuracy of the "specifications" in excavation, is evidence that a financial decision was a basis to not excavate to strong competent rock. If this "intervention" by DWR Field Engineer had not occurred, it may be possible that the large seams of highly erodible soil-like foundation material would have been fully repaired to competent backfill of concrete. The DWR Field Engineer's "intervention" evidences that a serious flaw was introduced that was a primary cause for the instability and the subsequent "blowout failure".

Fig. B.10. Initiating Failure Hole location reveals a deep seam of highly erodible foundation material (incompetent rock) that is many feet deeper than the grouted 5 foot deep slab anchor bars. Angle of seam inferred by dashed line. Image reveals the nature of why the "hole" location and the full 178 foot wide seam area was a structural problem area. The upslope "soil-like" foundation material is in a transition zone between the incompetent rock and the competent rock (downslope from the dashed line). Thus, the "communicating" slab forces through the load transfer bars would have experienced a differential in structural integrity or stability.

Fig. B.20. DWR Final Construction Report FCR 65-09. Critical Design Flaw linked to blowout failure. DWR reveals that the spillway foundation will include anchor bars emplaced in "clay seams". This evidences that DWR was allowing the slab design to have anchor bars to function from the "worst foundation available". This would include poor foundation materials such areas of clay and areas of soil-like highly erodible extensively weathered rock. The blowout failure area reveals this type of material (poor foundation materials). This evidences the non-ability of the anchor bars to maintain the integrity of anchorage in these clay and soil-like foundation materials. These materials are highly erodible in subsurface slab water flow. Scouring erosion would remove these seams of materials rendering a significant loss of pounds per square inch in anchorage strength of the anchor bars.

[Ray76]

New DWR vid shows rebar assembly

https://www.youtube.com/watch?v=JEC84KcBQdc

[EarthResearcher333]

#2 How Good - or Bad - is using a Toe Drain to detect Dam Anomalies? (When you don't have any working piezometers in the dam)

Oroville Dam seems to have an unusual behavior in its Toe Drain numbers (gallons per minute). How? By observing reservoir level data + rainfall amounts (4 month total inches) + combining the residual "drainage" factor of the Zone 3 sands, gravel, cobble, boulder "drying out" seepage.

In fact, the Division of Safety of Dams (DSOD) started noticing a change in the dam around 2003. DSOD started recording inspection statements in their reports on the overall low seepage and the low toe drain seepage of the Dam. In 2003 DSOD noted that Oroville dam's Toe Drain seepage is "low considering the high reservoir level" (898.96 ft). Then in 2005, DSOD noted "seepage is exceptionally low for a dam of this size".. Then again in 2009, DSOD noted "the seepage rate remains very low for such a large dam".

Whenever there is a change in patterns to the point to where DSOD inspectors are making such comments, this is usually an indicator of an internal change within the dam. Yet, the numbers were low, so no investigation was initiated.

Interestingly, at the same 2003 timeframe, DSOD started noting the Lush Greening in the Wet Spot on the left embankment of the dam. The "Wet Spot" photographs and inspection commentary continued in DSOD reports to 2016. Prior to 2003, there were NO mentions of ANY items regarding the Green Wet Area.. Driving this point home, the last two 2002 inspections (Jan 29, 2002 and June 13, 2002) both stated "No indications of seepage were observed on the dam embankment or groins." Then in 2003, in a June 19, Inspection report, "The thick grass and weeds at the left side of the dam…of the documented seepage area." appears in a DSOD report.

As Rainfall is a good indicator to the collection and drainage of this moisture to the toe drain, Rainfall should influence the toe drain seepage amounts such that this could give a useful indicator to a properly tuned "detector" to any sudden leakage problem developments. DWR is absolutely depending upon seepage, including the toe drain, as a method of getting around their lost piezometer instrument sensors (dead). As Rainfall will be absorbed and flow at different "conductivity" (ability to flow easily) rates within the fine voids of the sands and gravels in the Zone 3 embankment, depending on the internal moisture saturation levels to near dry conditions, an overall decay curve results in absorption, transmission (conductivity), and dehydration within the embankment to the toe drain can take a number of months to completely empty into the toe drain.

To get an idea as to how well the Toe Drain may act as an "indicator sensor", data was collected from 17 year span of DSOD inspection reports. This was correlated with historical archives of rainfall in Oroville, using the total inches of rain for the prior 4 months to the DSOD date of inspection. Note: Not all DSOD inspections reported the toe drain seepage. Thus the plot is based on the DSOD inspections over this 17 year span that did include the Toe Drain seepage gallons per minute (gpm).

The results are startling. In 1998 and 1999 the gpm toe drain output was identical at 23 gpm. Since the historical rainfall didn't go back to the 4 mo prior date in 1998, it wasn't included in this plot. But, the same 23 gallons per minute with very close lake levels in 1998 & 1999 indicated a good reference to reservoir level(s).

For some reason, the toe drain seepage dropped to a "trickle" (zero gallons per minute) in 2005. This was preceded by a near 50% drop in 2000. The reservoir levels were 768.86ft and 883.5ft respectively. This is a significant indicator of a problem, usually related to water not getting to the toe drain.

The greatest indication of a problem was in 2005 with a 768.86ft reservoir level, 16.27 inches of total rainfall in the prior 4 months (very rainy period), yet the toe drain was at ZERO output. After 2005, the dam has averaged a gpm rate that is over 50% lower than the 1998, 1999, reference point. Something has changed within the dam (indicator based on this pattern - perhaps DWR will soon provide information to explain the behavior change as DSOD continually noted how low the seepage is for such a large dam starting in 2003).

Summary:

Oroville Dam, based on this sampling of data, indicates that (1) using the Toe Drain as an "indicator" is not a wise choice and (2) there already may be an undetectable "leakage" path of drainage that is bypassing the toe drain. A common cause to this condition is from "clogging" of the original drainage zones to where water is flowing in areas to where an alternate "bypass" of the drains could form within the Zone 3 material (through an erosion effect called suffusion). All it takes is just a few feet above the mini-barrier dam to be "suffused", with the horizontal drain clogged at the mini-barrier dam, and large amounts of seepage could flow over and down into the Zone 3 & riprap are of the toe of the dam at the Feather River without even being noticed. IN this case, an internal fluctuations or larger flows that could be feeding the Green Wet Area could be completely missed.

Until DWR investigates and explains the extremely low seepage numbers (and the highly erratic behavior), and DWR explains the DSOD notations of "very low seepage for such a large dam", DWR cannot rely on seepage to be a substitute for detecting a serious internal failure mechanism (internal erosive leaking).

Fig 1. Highly Erratic Toe Drain. Infers an internal problem to the dam, the drainage system, the toe drain itself, or a combination thereof. DWR/DSOD could be "missing" large flows of water as these numbers are too low for such a large dam. (besides the erratic non-correlation)

[EarthResearcher333]

DWR's new "narrative" on the Green Spot - Back to "Rain" again - natural spring seems to be "out".

Erin Mellon, DWR's spokesperson, revealed a "new narrative" on the Green Spot (article Aug 9 below). Says that it's caused by Rain falling above the Green Spot and then internal soils mixed in the dam's construction brings this Rain down & out to the Green Spot causing grasses to grow.

Looks like the "natural spring" explanation fell by the wayside after pointing out that water does not flow uphill.

At least the constantly changing "narrative" is revealing DWR is trying to put together an explanation that doesn't immediately fall flat from engineering scrutiny.

However, this new "narrative" falls apart from DSOD Inspection data where the Green Spot was saturated (wet) during an extreme drought and 81 days of no prior rain. DSOD Inspectors, at that extreme drought condition, noted that the wet spot was tied to the reservoir level.

The second "twist" to the "new narrative" was lost in translation between Erin and the Reporter. Erin was trying to buttress the point that water was not flowing through the dam (i.e. causing the Green Spot) as a "drainage system" would capture this through-the-dam leakage.

This became garbled coming out as "there's a drainage system in place between the dam and the hillside and that drainage system collects any seepage that might be occurring".

To correct what was likely intended the rewording would be "there's a drainage system in place between the core of the dam and the dam's backside embankment and that drainage system collects any seepage that might be occurring through the core".

DWR's position is Revealing - they are putting some pieces together, but still falling short

This new "position" or narrative is revealing. (1) DWR is now properly looking at the flow direction towards the long horizontal strip of the Green Wet Area as HAVING to come from the center axis of the dam. (2) To block the narrative that this direction flow AND the source is "through horizontal cracks in the dam's core", they are taking the position that the vertical drainage system would capture any "through the dam core leakage". (3) DWR also is properly recognizing the existence of a soil based platform that "guides" the higher up water source (rain fall) outward to the Green Spot, except this platform is being explained as pre-existing soil material in the original construction. (4) Thus the "soils" from original construction are staying put and feeding the growth of grasses when the uphill rainfall resurfaces at this area.

What DWR is still missing

DWR is not "thinking" that the drainage zone (vertical 20 ft wide drain chimney) is "clogged" by transported silts, sands, clay/clayey materials from core & Zone 2 leakage. This "clogging" is typical from horizontal core cracking** that migrates "soils" into the drain zone (drain zone consists of gravels, cobbles, boulders). The soils create a "bridge" where water bypasses through the drainage zone and flows into the Zone 3 embankment (See Fig. 2). These same transported soils will form an outward "sheet" of clogging, like a horizontal shelf, to where it reaches the outer surface of the embankment. In this case, the Green Spot. These "soils" are resupplied as this leakage continues - and has been for decades (slowly). DWR is partially correct on the contribution of minor fines (soil particles) in the original construction as "black areas" were observed on the backside face of the embankment in the early days of operation. These black areas are likely from black sands from the placer mining of gold tailings from the Gold Dredge borrow area.

However, today, the Green Spot area shows brown colored soil, not the original black sands that leached out from early rains. So the soil base that maintains the Green Spot has to be replenished. Proof of this process is shown in the early "twin" settlement of the dam causing large green wet areas. (See Fig. 1). The early "through the dam" leakage of the "twin" differential settlement points caused large brown patches, or dirt patches. AS the dam settled out in this "twin" area (balanced in even settlement), the dirt patches were washed away and there is no longer any intense greening at these locations. Yet, the Green Spot continued to develop over time as the sharp slope/flat slope differential settlement on the left abutment continued to strain the core into causing horizontal cracking. Thus the leakage through the core eventually clogged the vertical drain chimney and the soils migrated to the Green Spot face.

An important factor to this internal dam leakage is that the leakage is eroding the sands in the Zone 3 embankment below the surface (the Green Spot is just part of this leakage or a "branch" to this leakage downward curve). This is the key to how the stark "erosion channels" formed below the Green Spot. Deeper below, sands have been migrated to allow the upper surface sands to percolate downward into these deeper voids - thus forming the erosion channels from simple rainfall over time.

DWR still hasn't explained where all the erosion channel "sands" have gone If you carefully measure the total length, width, depth of these erosion channels below the Green spot, you can conservatively come up with 22 dump truck loads of sand that has disappeared (219 cu/yds with a 10 cu/yd commercial avg dump truck). Where did all of this sand go?

To understand the potential magnitude of this situation, if the sand is downwardly percolating into the dam embankment, then a series of equivalent cubic yards of "voids" must be created to accommodate the downward percolation. Using a 3 inch conservative depth of the erosion channels, this represents a massive amount of sand "fines" material that has "disappeared". Is there a significant fissure that is transporting materials into the Feather river? Where could all of this material go? It certainly is eye opening considering the mystery DSOD finds in zero toe drain leakage (2005). How much leakage is there and where is it going?

The prior posting of the erratic behavior of the toe drain and its very low seepage output is explainable by shifting materials "clogging" sections within the dam. If DWR doesn't recognize all of these interrelationship threats as a serious issue, in time, the dam could risk failure modes - with not much warning.

**Core cracking Induced by Differential Settlement of the sharp slope hillside adjacent to a near flat slope hillside transition. A well known and documented earthen dam failure mechanism causing internal core cracking, erosion, and potential loss of dam if not mitigated before a critical erosion point. (See Fig. 2).

= = Article clip: "Erin Mellon with the California Department of Water Resources said there are actually several green spots on the dam where the type of soil used during construction allows rainwater from above to seep out, which contributes to more grass in those areas." "In the early days of construction, those green spots still existed. The second most important thing to notice about these green spots is there's a drainage system in place between the dam and the hillside and that drainage system collects any seepage that might be occurring," Mellon said."

= = end clip More at link:

Oroville Dam's Green Spot: Innocent Pool Or Big Problem?

http://www.capradio.org/articles/2017/08/09/oroville-dams-green-spot-innocent-pool-or-big-problem/

Fig 1. The proof history of early differential settlement, the "twin" green spots, and the future Green Spot showing "black sands" from internal seepage.

Fig 2. Differential Settlement Slowly Cracking the Core - Known Catastrophic Failure Mode to Dams - Soils being transported to Green Spot as the Drainage gravels are "clogged" - deeper flow of leakage eroded sand "fines" in Zone 3 allowing Erosion Channels to form over time from rainfall

[abb]

http://www.mercurynews.com/2017/08/10/oroville-dam-review-board-concerned-about-concrete-used-in-spillway-reconstruction/

Review board concerned about concrete used in spillway reconstruction

By Chico Enterprise-Record Staff Reports | Mercury News
PUBLISHED: August 10, 2017 at 7:06 am

Oroville – The independent consultants reviewing plans for the Oroville Dam main spillway reconstructions expressed some concerns in two recent memos about construction of the center part of the project.

That part of the spillway will get a temporary fix this year with roller compacted concrete (RCC), which isn’t as strong at the structural concrete that will ultimately surface the faces of the spillway chute.

The Board of Consultants’ ninth and 10th memos were posted on the Department of Water Resources’ website Wednesday, and both raised questions about the RCC.

Kiewit, the contractor handling the reconstruction has removed 2,270 feet of the damaged spillway. The top 870 feet and the bottom 350 are currently being filled with leveling concrete, with a layer of structural concrete going on top.

The 1,050 feet between will be filled with RCC this year. Next year it will be shaved back to allow structural concrete to be put on top.

http://www.water.ca.gov/oroville-spillway/pdf/2017/BOC%20Memo%209.pdf

http://www.water.ca.gov/oroville-spillway/pdf/2017/BOC%20Memo%2010.pdf

[abb]

http://www.vcstar.com/story/news/2017/08/09/federal-funds-help-oroville-dam-crisis/554868001/

Federal funds to help with Oroville Dam crisis
Tribune Content Agency Published 9:16 p.m. PT Aug. 9, 2017

SACRAMENTO - Federal disaster officials have agreed to chip in $22.8 million to help California pay the estimated $500 million cost of the Oroville Dam crisis.

Victor Inge, a spokesman for the Federal Emergency Management Agency, said Wednesday that the reimbursement is to cover some costs associated with the emergency as well as for removing the massive pile of debris that washed down from the spillway and plugged the Feather River channel below the dam.

Inge said the state’s requests for reimbursement still are being reviewed, and additional payouts could take several more months.

[EarthResearcher333]

U.C. Berkeley Interview with Prof Robert Bea on Oroville Dam & recent Report

An eye opening interview. Clips below. Prof Robert Bea's hard work has been well appreciated, even though he has taken heat in bringing the message and the uphill battle against instituting change for the good.

Be sure to read the last section where dam engineers and managers from all around the country have responded.

= = Article clip:

Bea and CCRM colleague Tony Johnson then launched an exhaustive study of the Oroville incident. The document resulting from that inquiry—Root Causes Analyses of the Oroville Dam Gated Spillway Failures and Other Developments—has just been released, and it makes for a riveting read. The paper not only dissects Oroville’s dire design and management problems in detail, but it also obliquely indicts America’s engineering culture as insensitive to risk, championing a certain cowboy élan and “get ‘er done” attitude over public safety.

We recently spoke to Bea about his findings. The conversation has been edited and condensed for clarity.

CALIFORNIA: You investigated some of the nation’s most spectacular disasters, including Hurricane Katrina, Deepwater Horizon, and the Challenger space shuttle. How would a major breach at Oroville compare to those incidents? And is such a failure even possible?

Bea: Yes, it is possible. And it would be worse than any of them. A breach at Oroville would send a wall of water down the Feather River, through the Sacramento Valley and ultimately into the Sacramento/San Joaquin Delta. It would destroy towns along the Feather and Sacramento Rivers, flood major portions of Sacramento, and blow out levees throughout the Delta, permanently flooding much of the region. The huge government pumps near Tracy that send water to Southern California cities and farms would be incapacitated. There would be tremendous loss of life and property, and it would be years before a permanent water delivery system to the south state could be reestablished.

Furthermore, it wouldn’t necessarily take a tremendous amount of rain and uncontrolled releases as we saw in February to trigger such a failure. It could happen on a bright, sunny summer’s day. The situation is that serious.

You had expressed concern about Oroville’s status prior to the spillway issues and evacuation. Is there anything you discovered in your most recent research that surprised you?

We were able to obtain some important documents and photographs we hadn’t seen before, and we learned a few things that, frankly, shocked me. One thing I had always wondered about was the construction of the primary spillway. The original design specified construction on rock and concrete, but the documents confirmed it was built on graded fill. I’d always suspected something like that, but had never found any corroboration. Graded fill simply doesn’t provide the strength and stability that rock and concrete provide, as we saw in February, when huge portions of the spillway were destroyed and tremendous erosion occurred.

The report also concludes that DWR has been aware of Oroville’s problems for many years, correct?

The main portion of the spillway that blew out is a section known as Station 3300. We found documents and photographs dating all the way back to a 1998 inspection report that confirmed there were major problems with this section. Essentially, they were screams for help that went largely ignored. DWR tried patching cracks, even filling up voids, but on that structure, finding the hollow areas is like trying to find a stud behind a wall by tapping it with a hammer. There’s a lot of room for error, and the repairs were far from adequate. Also, some of the patches actually trapped water so it couldn’t drain out, and that further compromised structural integrity. All this has been going on since at least 1998, so it’s no surprise that things went wrong at Station 3300.

What else did you find that concerns you?

There are very serious problems with the headgates [the structures that control water releases from the dam]. There is a lot of corrosion, and there are large cracks in two gate control tendons. Some of the gates don’t even open and close all the way. They’re like refrigerator doors that just stay ajar.

Also, we were alarmed by green grass growing on the abutments. That’s because the grass shouldn’t be green in that part of California during the summer and fall. It should be brown, so when you see lush green grass, it indicates there’s seepage through the dam face. What’s particularly worrisome is evidence we found indicating this seepage has been going on for about 50 years. DWR says that it’s just some ‘natural springs,’ and that’s it’s no cause for worry. But a ‘natural spring’ in that area would have to flow uphill, which runs counter to the laws of physics. And understand this: Any seepage through an earth-fill dam is extremely worrisome.

. . .

So what’s next for you? Are you going to continue your work on Oroville?

I don’t think so. Both Tony and I are getting up in years, and candidly, I’m getting tired, a bit worn out. I’m running out of teachable moments. I’m usually an optimistic guy, but I’ll be honest, what we’ve found with Oroville has been deeply discouraging. Since word of our work has gotten out, we’ve had engineers and water managers contacting us from all around the country, and the basic message is ‘Holy Crap! We’re having the same problems with our dams.’ Oroville is just the most obvious signal of a national, systemic problem.

= = end clip More at link:

Bob Bea Takes Us on a Deep Dive Through His Dire Oroville Report

http://alumni.berkeley.edu/california-magazine/just-in/2017-07-27/bob-bea-takes-us-deep-dive-through-his-dire-oroville-report

[EarthResearcher333]

Semi Tractor Trailer Driving through Oroville Spillway Gate

The size of the Semi Truck in contrast with the Spillway Gate Inlet seems to miniaturize the truck.

[Ray76]

Excellent research regarding the toe drain flow.

[The Westerner]

These dams are some of the world's greatest engineering feats! This picture of a truck at the spillway gates puts the size of the dam into perspective better than any so far. And this is only the spillway?

I well understand Professor Bea's weariness at explaining “it once more Like the Gods of the Copybook Headings.”.

I recommend to all who read this comment that you read the Prof's prediction of what will happen when or if Oroville fails. It's two or three posts back, posted by ER333. I also recommend that journalists repeat his prediction so all who live below are aware.

[EarthResearcher333]

A heartfelt Thanks. It is frustrating to have so much inside information locked away or blocked by CEII. When a person is able to painstakingly cobble together key data points, there's usually a pattern (change and/or erratic) that shows up where it explains the unusual commentary (DSOD Inspectors). So too with the Green Wet Area and internal Dam clogging association.

The Oroville archives reveal that the left abutment is riddled with seams, cracks, and fractured rock. A 1 inch crack in the left abutment rock in Diversion Tunnel 2 Rock excavation forced the contractor to alter construction. Then there is the near 100,000 cubic yard massive slide that occurred in the left canyon abutment (near the core, slightly upstream) in rock that was thought to be completed & ready (slightly fractured/weathered) AND the slide went up to 700 ft in elevation (highest point).

The original Hyatt Powerhouse access tunnel was moved based on "seams" and cracks in the left abutment.

It would not be surprising if there is a potential significant fissure or a cluster of cracks that may be porting material and water away from the bottom (near toe & Hyatt power plant access tunnel) Zone 3 left side embankment.

I find it very interesting that the dam is now at 1/2 the toe seepage rate it was in 1998-1999. It is almost as if one side of the dam may have clogged itself such that the clogged half has found an alternate drainage - thus the 50% drop change.

There should not be any unknowns in a high risk dam, especially when it comes to a potential of an internal erosion condition & possible destabilization of such a huge dam.

A hidden leakage path should scare the heck out of anyone living below the dam. I remember a public meeting with DWR in attendance where a citizen asked the DWR panel to raise their hands if they lived below the dam. The citizen had an excellent point in doing so.

[EarthResearcher333]

A heartfelt Thanks. It is frustrating to have so much inside information locked away or blocked by CEII. When a person is able to painstakingly cobble together key data points, there's usually a pattern (change and/or erratic) that shows up where it explains the unusual commentary (DSOD Inspectors). So too with the Green Wet Area and internal Dam clogging association.

The Oroville archives reveal that the left abutment is riddled with seams, cracks, and fractured rock. A 1 inch crack in the left abutment rock in Diversion Tunnel 2 Rock excavation forced the contractor to alter construction. Then there is the near 100,000 cubic yard massive slide that occurred in the left canyon abutment (near the core, slightly upstream) in rock that was thought to be completed & ready (slightly fractured/weathered) AND the slide went up to 700 ft in elevation (highest point).

The original Hyatt Powerhouse access tunnel was moved based on "seams" and cracks in the left abutment.

It would not be surprising if there is a potential significant fissure or a cluster of cracks that may be porting material and water away from the bottom (near toe & Hyatt power plant access tunnel) Zone 3 left side embankment.

I find it very interesting that the dam is now at 1/2 the toe seepage rate it was in 1998-1999. It is almost as if one side of the dam may have clogged itself such that the clogged half has found an alternate drainage - thus the 50% drop change.

There should not be any unknowns in a high risk dam, especially when it comes to a potential of an internal erosion condition & possible destabilization of such a huge dam.

A hidden leakage path should scare the heck out of anyone living below the dam. I remember a public meeting with DWR in attendance where a citizen asked the DWR panel to raise their hands if they lived below the dam. The citizen had an excellent point in doing so.