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.

[KC Burke]

For others I will add that the thumbnail standards are related to compaction test measurements. Compaction as Standard Proctor (the test method) is without soil being brought to optimum moisture content for the specific material used and compaction at Modified Proctor requires you measure how you approach the optimum moisture content for the tested soil type and then you measure compaction as a percentage of ideal compaction at that moisture content. You end up with something like 98% Modified Proctor under a strict standard.

In certain conditions, you want to wet or dry out the soil during compaction procedures to reach that optimum moisture as lab tested for that soil being used.

[KC Burke]

As an “armchair engineer” I will make some comments that may simplify this into what I call “the classic comic” version in honor of the old comics that simplified complex stories in the 50s. I will add to the above that placing the materials in proper lift thickness and measuring and repeating proper compaction yields an “engineered fill” rather than a bank fill or a non-compacted fill.

An engineered fill will perform to a certain standard and characteristics like “differential settlement” (the variation in settlement amounts over a certain time and load in different parts of a fill or earth mass) in a predictable, reliable and allowable manner.

When ER talks about differential settlement he is talking about settlement that is one amount in one area of the dam fill and a different amount in another area and the difference produces a shear or twist between them or other areas not settling. This produces a weakened path for water or stress to work its way through the material.

[meyer]

Looks like the spillway is now open again as promised.

[EarthResearcher333]

Piece by piece Clues to the Erosion Channels under the Green Wet Area - What is Differential Settlement? Can it crack the core?

Differential "Settlement" is an uneven rate of a compaction/consolidation of the dam from gravitational, hydraulic, and structural forces over time. "Differential settlement" effects could be from construction defects in non uniform material emplacement or from the construction compaction process itself. Earthen dams are carefully constructed to assure that the Zone fill materials and the construction compaction process are precisely controlled and monitored. However, one engineering consideration of an earthen dam is that there is a potential risk, from the undesired "differential settlement", due to sharp irregular changes in the canyon wall slopes. The ideal canyon would have even slope angles from the top of the dam to the bottom, or toe, of the dam. Earthen dams require a strong rock base in the canyon walls to form the left and right abutments where the future dam will be compacted within the canyon. (One of the reasons for having a density of the rock of a canyon base to the Zone fill density ratio is for seismic stability (liquefaction phenomenon for one)).

Over time, the Zone fill materials will "move downward" and slightly deform into the canyon in a tighter bunching of the earth dam materials. This is called "settlement". Survey markers -noted as monuments - are cemented into the surface of the dam to enable future survey measurements for monitoring the state of this normal "settlement" process. Why? This is an important safety factor to determine the "health" of earthen dams. Any sudden shift of a slope area, or an unexpected shift rate, indicates a potential threat to the dam from a possible "slope instability", or an another indicator of an internal anomaly. These survey markers allow periodic measurements to detect small changes for this reason.

One danger to Earthen dams is inducement of "Differential Settlement" from a canyon wall that has an irregular slope change. This is called a "steep rock abutment" transition slope from a "less steep, or more 'flat' slope" along the elevations in the canyon. Why is this a danger to earthen dams? It is because the steeper slope Zone fill area will experience different compression stresses than the 'flatter slope' compression. As sections of the Zone fill material respond to these different forces, the steeper area may induce an "pulling" or "dragging" shear type of force within the internal Transition layer to core layer boundaries. This effect has been known to cause horizontal seams (longitudinal) to be pulled open in the dam core (similar to a sewn clothing seam being pulled apart, leaving a rip along the sewn seam). This is a known failure mode to earthen dams and is taken very seriously [1][2][3].

Oroville dam is constructed upon a sharp slope transition boundary. This boundary is on the left abutment of the dam. The same side as where the Green Wet Area is precisely located (at this "differential settlement" transition region in a sharp slope change boundary).

So what does the survey data show? Oroville dam has "Differential Settlement" above the Green Wet Area. At the row of emplaced 750ft elevation survey markers, actual survey data from 1970 to 1975 reveals a sharp transition of "differential settlement" measurements that uncover this effect at Oroville dam. This settlement profile most likely is continuing today as the "settlement" process will continue for the life of the dam.

Is this a problem? Only if "sign" of leakage, unexplained wet spots, or unexplained "erosion sign" develop. The failure mode of internal leakage is that the erosion process within the core region could develop and escalate to where there is no ability to arrest the escalation. References below have noted that this "failure mode condition" may exist for years, until a sudden transition point to failure. Piezometers within the dam typically would measure the internal saturation or leakage from such a condition. However, DWR has sliced bundles of the hydraulic tubing to their broken Piezometers in addition to the last 3 piezometers being non-meaningful in their ability to measure correctly. Thus DWR has zero functional piezometers within the dam to monitor or detect any internal anomalies from a defective phreatic water level seeping into areas and at volumes of flow that pose a potential threat.

In normal circumstances, from a critical safety operational criteria, a dam would not be allowed to operate without these important Piezometer Sensors. An earthquake could induce a defect within the dam that would be "undetectable" without these sensors. The 1975 Oroville earthquake caused sharp pressure rise of 54 feet of piezometer pressure in one area in the central core of the dam. The dam withstood the forces, but without these Piezometers, the engineers would not have had the ability to do a stability risk assessment. Today, if an earthquake of a given size were to occur, DWR would not have the ability to assess the danger within the dam to warn or inform the public.

[1] Design and Construction of Embankment Dams - Differential Settlement Failure/Cracking Fig 2.4(a) sharp abutment change - http://aitech.ac.jp/~narita/tembankmentdam1.pdf

[2] Embankment Dams-Design Standards No. 13 - Longitudinal Cracking from Differential Settlement pg 5 - http://www.damsafety.org/media/Documents/DownloadableDocuments/ResourcesByTopic/DS13-11.pdf

[3] Lessons Learned from Dam Incidents and Failures - Steep rock abutments leading to "differential settlement, cracking, and failure by internal erosion - http://damfailures.org/wp-content/uploads/2015/07/Lessons-Learned-Complete-List.pdf

Oroville dam survey data revealing "differential settlement" directly above the "Green Wet Area" - Known failure mode to Earth Fill dams if any core shear stress induced internal defects erode to an escalation point.

DWR is operating the dam with none of its original critical safety Piezometer instruments working - either broken or non-functional. DWR is unable to detect any internal phreatic surface water flow anomalies inside the dam. FERC has been asking DWR to put in new Piezometers (phreatic surface monitoring) for many years.

[KC Burke]

differential settlement

[KC Burke]

Paste this into a browser or click:
http://damfailures.org

[EarthResearcher333]

Piece by piece Clues to the Erosion Channels under the Green Wet Area - Erosion Channels, where did the "fines" go?

As evidence has been presented that the Erosion channels are slowly getting wider, yet DSOD Inspectors have not been able to observe any water in these channels when the Green Wet area is saturated, what is happening? Processed imagery data reveals that "fines" (sands, & tiny minus gravel) are being removed and causing the underlying cobble & rock to be further exposed & remain or even loosen and tumble. Yet the channels are gradually deepening and widening (Imagery data). Where are these "fines" going?

DSOD inspection reports do not reveal any discovery of piled up "sands" accumulating at the bottom seam of the hillside. With the numerous individual Erosion channels averaging from 5 feet to 7 feet wide, and the combining of these erosion channels measuring from 20.55 ft wide and greater; with the length of the channels, the depth (from shadows & cobble boulder increased exposure), surely there must be a volume of accumulation of material somewhere?

Could it be possible that the "fines" are migrating downward in a form of an "intergranular seepage"? If so, this would require a "granular" migration chain reaction from a subsurface sequence of "void" channels that these "fines" may migrate into. Then what formed these deeper "granular voids"?

Eventually rainfall percolation movement of these "fines" should eventually stack up and backfill to the surface. If so, then why do the Erosion channels keep growing? The only answer would be that a bigger subsurface condition has either already occurred or is continuing to occur. This "subsurface" condition would had to have been a large area migration of deep subsurface "fines" that were ported deeply downward & went somewhere. Looking at the full square footage of the Erosion channel area, if this whole swath was scoured in a capillary type of vertical downward migration erosion of "fines", this would allow the individual Erosion channels to form as they have - naturally from rainfall. The key difference is that the rainfall is not "pushing" the fines downhill, but is facilitating the "percolation migration" of these fines into the Zone 3 fill.

The original forces of a large hillside saturation, and likely combined with some rainfall at the time, are the only positive hydraulic pore pressure conditions that could upwardly "disassociate" the original construction consolidation of the fines in the Zone 3 fill. More so, the saturation likely was from a wide area subsurface flow. This subsurface flow, of a higher hydraulic pore pressure, would have the ability to "migrate fines" downward in a bottom-up back erosion condition where the "fines" ended up inside of the bottom horizontal Drain Zone. This Drain Zone would easily accept the migration of "fines", from a strong subsurface flow, as the Drain Zone is comprised of gravels, cobbles, and boulders - plenty of space for a large volume of "fines" to be deposited. As long as the Drain Zone is able to accept this continued "depositing", the upper strata of Zone 3 areas will be micro honeycombed with flow channels for more "fines" - simply by a mix of rainfall entering the erosion channels, eroding & migrating more surface fines into the channels + then percolation downward. This process also deepens the channels as more fines are eroded and carried downward via percolation. (note: the average "flow" of water would be thin as there would be a continuous percolation absorption compared to a normally "combined" flow in a typical channel - thus the missing DSOD information on why there are no "piles" of accumulation at the bottom of the hillside seam.. the "thinness" of a channel flow, in a heavy rainstorm, would be determined by the percolation rate absorption to sq ft deposition rate of the precipitation).

What this reveals is that there is likely a wide area "flow" condition below the Green Wet Area that is unseen. If this subsurface flow contains silts, soils, clays or clayey "fines" from the Transition Zone or the Core, this too would be "unseen" as this flow over time would be deep under the Zone 3 surface. This a key reason why there are no thick greening areas in these "Erosion channels" - there is no upward surface deposition of a vegetative soil base. All of the "fines" migration is evidenced as a downward percolation flow.

[EarthResearcher333]

Piece by piece Clues to the Erosion Channels under the Green Wet Area - Proof that the Reservoir is the source to Green Area Seepage?

Simply, Yes. The simple assumed "test" has been - If you have rainfall, how do you know the greening is not from the rain?

This all started from DWR's PR town hall & press release meme of "rain falls…then grass grows".

I personally appreciate everyone putting up with my "extensive" guided tour. Sometimes this is necessary when dealing with a highly subtle and complex interrelationship puzzle. After all, the best have been puzzled at DWR for decades over this problem.

I have a few more posts to go. But I'd like to share something now that reveals what DWR already knows (or should know) - that the reservoir is linked to the Green Wet Area seepage. This information also reveals that DWR's intention of trying to directly limit the association of water at the seepage area to "only rain" - and avoid their own DSOD inspector's evidence - is highly misleading to the public.

Yes the grass browns in the late summer, I will have an extensive post on all of this as to what is going on. But water DOES exist at the seepage area - EVEN IN DROUGHT conditions (i.e. zero precipitation for 81 days & a hot summer). DSOD has documented this in 2015.

Thus all of the boaters driving by wouldn't know this as the grass was brown, yet the water was still percolating and present. DSOD knew this as they discovered it AND noted it with regard to the lake elevation level at the time of the inspection.

This evidence strongly minimizes the "natural spring" and "rainfall" posited theories by DWR ("natural spring" self eliminates by the "uphill" water flow necessary to reach the upward horizontal greening elevation progression).

DSOD's own evidence that the Seepage at the wet area is from the reservoir. July 20, 2015 DSOD Inspection report notes Seepage in the Wet area even in drought conditions (grass brown). Yet this has not been revealed to the public.

Precipitation to Lake Level elevation chart noting the Inspection date. Original Graph courtesy of Freeper Ray76.

[meyer]

Thank you for your research and continued explanations. The stuff is fascinating to me.

Meanwhile, on the spillway (and I hope I’m not repeating a prior post)...

http://www.water.ca.gov/oroville-spillway/pdf/2017/Memorandum_050517.pdf

[janetjanet998]

drone video of the spill
https://www.youtube.com/watch?list=PLeod6x87Tu6eVFnSyEtQeOVbxvSWywPlx&v=avOwvE7yfso

at 3:09 you can see the stripes on the inside north wall they still look straight(unless they reset them recently)

[meyer]

Thanks, Janet.

Despite the damage, the video is still impressive to watch.

Seems that other than a little rinse, the water flow is again fairly clean at 30,000.

[meyer]

Correction - according to the daily report, the spillway is at 25,000 and the Hyatt Powerplant is at 5000.

[jpal]

To EarthResearcher333: as always, I am amazed at the breath and depth of your posts.

However, I would appreciate a point of clarification:

I’m not sure I’m correctly interpreting the “differential settlement diagram” from DWR that you provided in post 3624.  
It appears that the scale on the right of this plot is in tenths of feet (of settlement, I assume).  If so, your small circled arrow on the right appears to indicate about .03’ settlement at around station 65, and the larger circled arrow to the left indicates around .18’ settlement at station 57.  That would be less than 2” differential settlement across that distance, which doesn’t seem sufficient to shear the dam and induce cracks that water could flow through.

Am I not interpreting this diagram correctly?  
What is the actual magnitude of differential strain in the dam that would cause the phenomenon that you describe?

[EarthResearcher333]

"That would be less than 2” differential settlement across that distance, which doesn’t seem sufficient to shear the dam and induce cracks that water could flow through."

If you'll notice in the text overlaid in the settlement plot you quote, this plot was for a short window of time (i.e. 5 years verses the 50 year life of the dam) thus 90% of the 100% of the actual settlement data is not shown in this plot. (I would suggest that an inferred conclusion. when missing 90% of 100% of the data, may be premature.)

Given this, there is a clue that may help understand just how much "surface" measured "settlement" translates into an internal effect in the actual dam leakage penetration and volumetric resulting flow.

If you look at the top crest survey data (922ft elev), at 55+00 to 57+00 to 59+00 - there is a residual downward "V" in 6-1971.

IN 1972 and 1973 this "V" balances out or levels out (overall slope angle). What this "V" is is the remainder of one of the two original "differential settlements" from 1967+ early years that is missing (early plot data not available in the referenced report). BUT the "V" reveals the leftover results that caused the massive saturation, of the left side, of the two "twin" flows within the dam leakage noted in prior images (the first Greening Areas of the dam - that no longer exist today) (see image below).

"Back extrapolating" the plot, these twin differential settlement shear areas - located on both sides centered over the toe axis dam hump layer - would be near 3 to 4 inches from an external reference AND at the crest of the dam. The "crest" is located atop the core region (monuments emplaced in downslope edge side near the crest dam road).

Translating "external surface" measurements to actual potential "seam widths" is a complex venture. In this case, when the measurements are on the "top" of the core, is this "closer to the downstream transition zone - or centered exactly on the core?" either way, it is difficult to extrapolate the actual equivalent "opening" width. But the data is useful in that this "residual V" is tied to observable results/effects in documented history leakage. You can see the dramatic effects of this (image below). The internal flows were completely saturating nearly the entire downslope Zone 3 fill. This can only be done by a POSITIVE hydraulic pore pressure such that upward + diagonal flow exists, even if rainfall were contributing, the "upward" pore pressure existence of the Zone 3 fill deeper saturation kept the hillside from percolating the moisture downward (note the clean areas that did percolate properly IF rain present). The leftover "dirt patches" revealed the extent of porting of internal core materials and the positive pore pressures to port the material(s) to the Zone 3 surface. Fortunately, this "twin" differential settlement "closed" by the balancing out of the combined vertical Zone fill - this was facilitated by the fact that these areas were in the central part of the dam and that the "hump" was a temporary densification "fulcrum" that assimilated into the rest of the layer 1 "settlement". Upstream Zone 2 Transition zone silts assisted in the sealing of the core seams.

(side note: this reveals how "irregularities" in the base & abutments of an earth fill dam can be so dangerous - KC Burke provided a link where you can search out dam failures from hard conduit structures that caused "differential settlement" failure of the earthen dams [hydraulic fracturing of the above embankment - fulcrum forces]. If the toe axis "hump" fill were to be rock, Oroville dam would not exist today.)

So this gives a person "actual" reference information as to what results may occur via "external surface" data with respect to the "internal effects" regarding a volumetric flow response.

What makes the current "Green Wet Area" problematic for a continued "differential settlement" is that the left rock abutment will not "balance" out as did the original toe axis "hump" - i.e. the rock hillside wins. Thus the differential settlement will always be present.

It becomes a game of how much transport material may be provided by the upstream Transition zone to continue to "heal" leakage in the core. Keep in mind that this "transport" is from an erosion fill of the core to where the core eroded away more of its plastic seal base. Eventually, the structural integrity of this plastic base becomes compromised as the "silts" fill volume increases. It's a chain reaction. DWR has no idea how much internal waterflow which may be occurring that is "unseen".

Early Dam operation reveals massive internal flows, reaching the Zone 3 surface, depositing "growth medium favorable" internal Core material - forming the first Greening Areas. Settlement (external) back extrapolated to be near 3 inches at dam crest for these twin seam area leakage defects (since collapsed & healed).

[EarthResearcher333]

Hi meyer, there are a few interesting "new" items in this report that are very unusual. They state that there was a "contributing" waterflow source. This may be in reference to the spring that is 200 ft slightly upslope and West of the failure area. I suspect this comment of "contributing" is relating to a historic spring waterflow that cut across the foundation causing the high volume of weathered rock. This "percolation" seam is in one of the early dam construction photos (imaged processed) posted upthread.

I have new evidence that sheds light on what may have plugged the drains in the failed zone. p.s. it was not from tree roots...

When I get around to it I'll try to post this new information.

[EarthResearcher333]

Piece by piece Clues to the Erosion Channels under the Green Wet Area - How does Green Wet Area become Brown Grass damp Area?

During periods of hot, dry conditions, both cool- and warm-season grasses can go dormant as a protective measure. If grass receives sufficient moisture, growth slows and blades remain green. History of DSOD inspection reports reveal a direct relationship to these factors: Example: - DSOD 2/2/2011 Inspection report "The usual green vegetation on the left side of the embankment is visible near the center of the picture. The area tends to dry out in the late summer".

First, where did the "dirt" come from?

Oroville has a seasonal weather pattern that is hot and dry in the summer and late summer times. However, one of the first questions that should be investigated is - "How did so much rich "favorable" growth soils occur in the large 164,648 sq foot area of the Green Wet region?" Was this through collection of fine trace soil particles from the upper Zone 3 hillside? There is evidence of wispy grass growth based sustaining material in the Zone 3 fill as seasonal rains reveal these wispy grasses on the full area of the slopes. Yet, rainfall will percolate downward into the Zone 3 fill by design (sands, gravels, cobbles, boulders). To form such a soil densified surface layer of 164,648 sq foot area of the Green Wet Area seems improbable for any "smart" rain "lateral" transport and focus to create such a large 164,648 sq ft "dirt spot" base. If you estimate the depth of this deposition, the cubic yards of material wouldn't add up from any upper Zone 3 migration scenario no matter how strange the rain could redirect its percolation back to focus on this area. (even at a fraction of an inch in depth over this sq foot area, the volume is significant [cubic yards]). Where did the growth medium come from? Has it been "ported" from the core region over these many years?

Back to the Grass…

When grasses reach a "Heat stress" condition, the response by the grass to these high temperatures, is to preserve itself and become dormant (i.e. turns brown). Some grasses are more resilient to heat stress as their photosynthesis processes are different and they thrive longer before becoming dormant. One example is the notorious pesky crabgrass. The key onset of heat stress-to-dormancy transition is 90 degrees Fahrenheit. One more step is required to "factor in" for the actual temperature conditions the grass may experience. That additional factor is from the sunlight thermal absorption in the Zone 3 materials. As the downstream dam face is southern, and the dam face is angled upward to the sun elevation angle, the efficiency of absorption of thermal energy is significant. The average daytime temperature in Oroville in July is 95F. Given a bleached light color of the Zone 3 fill cobbles, gravels, sand, boulders, a comparable energy absorption surface temperature increase would be similar to a concrete surface. Animal researchers, determining safety levels for pets, have tested the thermal rise on different surfaces during the hours of the day. This chart (below) is a very close match to the peak day temperature (95F) to Oroville's July peak day "average" temperature (95F). Using the concrete elevated surface temperature conversion, this would evidence that the Zone 3 surface would be at/near 125F. This is well above the 90F transition temperature that grasses trigger into self preservation "dormancy". If you use the "Grass in the Sun" conversion, the temperature is 105F. Still well above the 90F transition temperature into dormancy.

What about the Water?

The next factor to sustaining any greening, even with hardy warm-weather tolerant grasses, is the sustained water base. Yet, with Zone 3 fill surface temperatures at/near 125F, what happens to the evaporation rate of any upward and/or diagonal percolation of subsurface water? When you mix in the very arid typical summer conditions at Oroville, a 3 to 5 mph wind, and 125F surface temperature of the Zone 3 fill, the lbs per hour of water evaporation is significant. Depending on slight variations on these variables (such as wind speed), the evaporation rate could remove up to hundreds of gallons per minute for the full 164,648 sq foot Green Wet Area region. Certainly this moisture removal capacity would swiftly influence any grass growth transition into dormancy. The surface area of the Zone 3 fill would have the most intense effect of this moisture evacuation. Yet, there is no complete information as to "how" and "what" the mechanism is in how the moisture "reaches" the extreme lateral reach to the outside surface of the Zone 3 face. It could be possible that there is a plurality of "water flow" at different depths within the Zone 3 surface to where the outer layer is dissipated swifter compared to an inferred heavier "main" flow deeper below. So, in essence, the Greening is likely not a direct measure of the full seepage flow. The Greening is the result of a partial amount of the flow that moisturizes and wets the "growth medium". Seeking to extract a definitive assessment using Greening and Lake levels, are fraught with the more dominant effects of the "partial reach", the "strong evaporative losses" of the surface layer, and the "heat stress + aridity" that triggers Greening dormancy.

DSOD has already established that in "on-going drought conditions" that there is seepage present in the Wet Area. As this observation was done in an inspection with 81 days of zero precipitation, in the peak heat of Oroville avg (95F July 19) and the Inspection was done July 20, the presence of seepage at a 125F surface, with the evaporative power of removing up to hundreds of gallons per minute, is a testimony to what is really going on with an evidenced supported strong internal water source. (note: the grass was brown at the time of the inspection)

Oroville weather average temperature chart. Grasses transition to "dormant" (i.e. turn brown) at a threshold of 90F. Elevated Zone 3 fill temperatures in the peak summer are from 105F (grass surface) to 125F (Zone 3 surface) from direct sunlight thermal absorption.

Surface temperature graph (animal safety research - taking your pet for a walk) - sunlight on different surfaces - ambient temperature, grass temperature, Zone 3 equivalent absorption rate referenced to concrete surface.

[EarthResearcher333]

Piece by piece Clues to the Erosion Channels under the Green Wet Area - Guided Waterflow "Steps" from layered sections?

Keys to all of the mysteries of these outstanding sets of questions & evidence point to a "guided" water flow in the form of "steps" in the Zone 3 fill. These "steps" are at the seam boundaries of the original sectional layered construction elevations. Seasonal rains would have enabled a densification of the compaction process where hydration of the fill material, as its being roller or sheepsfoot compressed, will densify greater when the material has a higher hydration. Since the seasonal rains are typically in the cooler period of Oroville's weather, the densification is effective. Thus, having densified strata at these seams, water flow is less pervious as this layer has a level of resistance to the percolation rate. Another factor that comes into play is that any trace "soils" in the Zone 3 "lifts" that were compressed would tend to concentrate these trace soils to the compression surface. This illustration is the culmination of the "Mystery of the Erosion Channels". Oroville dam has a leak source, pointing directly to the core, that is a threat to the dam. Not rain. Not a natural spring. DWR is "flying blind" with no working Piezometers. The Green Wet area is a form of a tip of an iceberg… what is really going in further inside the dam? High risk infrastructure cannot tolerate a PR campaign of "rain falls…then grass grows" in light of all of the extensive evidence.

illustration is the culmination of the "Mystery of the Erosion Channels". Evidence for behavior of Early dam operation - saturation of hillside showing construction seams - greening areas from soil depositions + saturation. Same pattern & characteristics following today in the Green Wet Area".

Early Dam operation reveals massive internal flows, reaching the Zone 3 surface, depositing "growth medium favorable" internal Core material - forming the first Greening Areas. Early dam operation - saturation of hillside showing construction seams - greening areas from soil depositions + saturation. Same pattern & characteristics following today in the Green Wet Area".

[jpal]

EarthResearcher333:

One thing that struck me regarding the DWR settlement report that you cite was that the date of the last survey was apparently mid July of 1975.  Wasn’t the Oroville earthquake on August 1 of 1975? Assuming that it took a few weeks to generate this report, then it would have come out right after the earthquake.  I would think they would have included at least one more survey to assess the pre-quake settlement to the post-quake settlement, which most plausibly was greater than 2”.  

DWR’s data collection, management, and reporting practices are a mystery to me.

I also find it amazing that DWR could just “loose” most of these survey monuments.   Them loosing functionality of piezos buried in the dam is at least fathomable, but loosing monuments on the surface?  I would think any decent survey crew armed with the original notes should be able to forensically find some or most of them.  As you indicate, knowing what that settlement is today would be quite a useful piece of this puzzle.  

You cite a July 2015 DSOD report that says there was still noticeable but “relatively low” seepage, even when the lake was at 700’.   Isn’t the elevation of the green spot around 660’?  If the wet spot has noticeable seepage with only 40’ of head, then it should be flowing a lot better at 900’, with 6 times that head, like it for had much of 2011.

In one of Scott Cahill’s latest videos https://www.youtube.com/watch?v=y-7DSoTlc_Y , at around 10:25, his wife quotes an October 2011 DSOD report that says the wet spot still had “lush vegetation that should be trimmed”.  She even remarks on how unusual this was for October.  

I haven’t been able to find this DSOD report.  However, 2011 was the highest the lake has been through the summer, so if the green spot still had lush vegetation at that date, then the water had to be coming from the lake.  I guess it could be that all my boating buddies were just too drunk to notice.

Do you have access to this Oct 2011 DSOD report?  If so, could you please post a link to it?  

It appears that most of the DSOD reports repeatedly call for DWR to actively monitor this wet spot, which they have repeatedly ignored. There are relatively cheap wireless moisture and temperature sensors which are used in agriculture that could be placed in this area. If that data were correlated with solar intensity, wind speed, humidity, rain fall, and lake level, then it should be possible to get a better handle on how much water is coming thorough. Hopefully, getting DWR to install better instrumentation will be a positive outcome of this effort.

However, in my mind, “lush vegetation” growing in October would be definitive proof that the wet spot water is seeping from the lake.  

Then there is still the question of how the vertical channels underneath formed, which I’m hoping you’ll elucidate further.

[EarthResearcher333]

FYI - Professor Robert Bea testified today at 1pm in a legislative hearing. Most likely, there will be new news articles about this hearing forthcoming. Below is his commentary regarding the dam leak issue yesterday - before todays hearing (interviewed on the new prelim spillway failure analysis).

Oroville Dam: Potential causes of spillway collapse released

--- Article clip (emphasis mine):

Bea would like to see a shift in the way DWR and the Federal Energy Regulatory Commission operate, to own up to mistakes, try to learn from them and be more transparent going forward. “They want the public to like them, so they call seepage from a dam a ‘natural spring,’ say no reports show any sign of distress,” he said. “That’s distortion of truth and fact. This is a time for honest people to stand up and the other ones should sit down and shut up, (or) we’ll be destined to keep repeating these things.” Bea will speak at a legislative hearing at 1 p.m. Thursday regarding the Oroville Dam on a panel with Butte County Supervisor Bill Connelly and Ron Stork of Friends of the River.

-- end clip

[EarthResearcher333]

Hi jpal, you are correct on the earthquake date. The plots in the report only have survey data to July. I believe the survey was done as an annual inspection function, rather than data for "after" earthquake settlement. I will check on the October 2011 DSOD report to see if I have this copy. Give me a few minutes....