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Oroville Dam History Images - Reveals Heavy soil migration from internal leakage erosion - Differential settlement Twin Columns - Potent Green Leakage area today

More discussion: This Historical sequence of Images reveals strong evidential behavior and existence of a persistent Leakage problem within Oroville Dam. This original leakage behavior of the first "settlement" phases of the dam, caused "twin columns" of strong seepage which deposited thick soil patches from internal dam soils migration. The "twin columns" of this large seepage were centered on the original "hump" layer which induced differential settlement stresses to the core region resulting in the mirrored hillside saturation. Note that there is NO greening along the other areas of the dam - as an example of the "rainfall" theory proposed by DWR. The early problem Green Wet Area was in its infancy in seepage as illustrated by the dark patches near the left abutment of the dam. Image item (1) shows NO greening or soil "patches" in the original construction.

After the significant seepage of the vertical twin columns (2), large internal soil deposition "patches" are observable that resulted from the prior "significant dam seepage" (3). These 'soils' are from within the internal dam and were migrated by a persistent leakage flow leading to a thick deposition at the surface slope. NOTE: rains would have had to concentrate, then "upwell" (not likely), to form such a collection of soils from the zone 3 shell layer, yet fluid flow physics defies how these oval formed patches could occur from an "even slope rainfall" theory. ONLY an internal flow path (inside to the outer surface layer) could form such a concentration and pattern of soil. The fact that there are twin soil patches, centered over the original "hump" toe axis layer, strongly supports a differential settlement leakage path through the core in two regions of the upper twin columns. Over years, these soil patches have been washed away as the internal seepage condition "sealed itself" (i.e. Zone 2 silts, sands, migrating into the core to reseal as designed) and the "differential settlement" over the toe axis "hump" balanced out.

Yet, there is an area that continued to experience "differential settlement". That was along the steep slope of the left abutment. Thus the internal seepage and erosion developed early and is continuing today to pipe soil material -along with the increased presence of water flow- to facilitate large vegetative growth (greening) on the dam face. (See 2nd image from April 2017). Because of the physics of the internal phreatic shelf (waterflow shelf) inside this long developing internal erosion channel (longitudinal seams leaking within), there likely is seepage flow that is "unseen" at the surface. This would be due to a seepage percolation through the erosion soil shelf that curves in a subsurface flow (parallel but under the surface of the "downhill erosion channels". What determines how much leakage and what volume reaches the Green Area Wet Spot is due to reservoir levels, how long the reservoir has increased the pore pressure within the core regions, and the hydration state of the outer zone 3 material.

These factors would affect an assessment of seasonal greening assuming the cause to be from seasonal weather. But the internals are more complex. Essentially, the phreatic line (water level) and its curvature are dependent on these factors. When the conditions are suitable, the phreatic curvature leakage upon the erosion soil migration "shelf" determines the point at which the leakage at the outer surface intensifies, then "greening" accelerates, thus giving a "seasonal" association.

Original leakage behavior of the first "settlement" phases of the dam, caused "twin columns" of strong seepage which deposited thick soil patches from internal dam soils migration. Soils were concentrated forming two "patches". ONLY internal core flows may cause this result. (not rainfall).

Heavy Greening and Leakage in 2017 (conflicts with "rainfall" theory). Unknown total flow rate and extent of internal uncertainties to the erosion channels makes this situation an unknown risk. Leakage, strong dam face erosion channels, soil base, large greening all above steep slope transition (differential settlement dam risk).

As usual, excellent information and analysis.

Key unasked question: Is there currently detectable water flowing from the dense green area through the easily visible erosion channels?

If so, how much?

If not, was there when the lake was at a higher level than it is right now?

It seems it must be one or the other, or both. Otherwise, how did the multiple obvious erosion channels form? They clearly originate in the green area, they are not visible elsewhere on the dam, and it was NOT rain.

The green area is growing, which means the water flow is increasing.

So... HOW MUCH WATER?

Presumably the DWR knows the answer and has chosen not to tell us. It’s even worse if they DON’T.

I've gathered monthly precipitation and lake elevation data for the past ten years. If dated photographs of the dam can be obtained it may help determine whether it is precipitation or raised lake elevations which most closely correlate with appearance and size of the green area.

                                        Precipitation

       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
2007   0.0   5.7   0.4   1.7   0.6   0.5   0.4   0.0   0.3   1.3   0.8   4.1
2008   4.5   3.6   0.2   0.3   0.0   0.0   0.0   0.0   0.0   1.8   2.5   2.7
2009   2.2   6.6   2.1   0.4   1.9   0.2   0.0   0.0   0.6   1.7   1.4   3.8
2010   8.0   3.1   2.3   4.5   1.4   0.0   0.0   0.0   0.0   2.6   2.6   7.2   
2011   1.8   4.1   6.9   0.6   2.7   1.1   0.1   0.0   0.0   2.1   1.6   0.3
2012   4.4   1.1   5.8   2.2   0.0   0.1   0.0   0.0   0.0   1.4   4.4   7.2
2013   0.7   0.5   2.0   0.8   0.3   0.6   0.0   0.0   0.8   0.1   1.5   0.3 
2014   0.4   6.1   5.2   0.3   0.3   0.0   0.0   0.2   0.7   1.2   2.6   8.9
2015   0.1   2.5   0.4   1.5   0.0   0.0   0.0   0.1   0.1   0.2   2.7   2.9 
2016   7.2   0.7   6.8   1.1   0.4   0.1   0.0   0.0   0.0   3.2   2.2   5.5
2017   7.5   8.6   2.9   3.0   

precip inches rounded to tenths

https://www.wunderground.com/history/airport/KOVE


                                   Avg Elev Lake Oroville

       Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec
2007   850   858   866   871   866   852   818   782   748   730   713   699
2008   703   716   737   753   757   748   718   693   680   675   667   661
2009   661   679   758   787   804   799   760   724   712   708   695   674
2010   675   704   732   769   813   838   833   803   770   754   749   767
2011   811   830   854   869   888   897   899   892   876   860   853   838
2012   827   830   840   875   898   891   860   819   789   770   762   812
2013   834   848   857   868   859   842   813   777   751   741   724   711
2014   703   711   739   765   764   745   714   688   677   668   651   686
2015   719   744   760   763   748   729   702   679   673   670   658   656
2016   690   754   829   881   890   875   836   787   753   738   733   755
2017   834   861   851                           

lake elevation rounded to feet

https://cdec.water.ca.gov/cgi-progs/queryMM

Station ID   ORO      Sensor Number   6       Date    04/17       Span   144

I'm confused why the DWR engineers wouldn't be more curious about anomalies in the location of the actual phreatic line, especially in cases like this. One can theorize all they want, but in the end this is something that looks like it can be determined fairly easily with readily-available instrumentation.

Peizometers are not exactly rocket science. Pneumatic ones are less than $200 apiece, and plenty of data logging or real-time electronic ones are less than $1000. For some modest investment (let's say < $275M) you could have a fairly robust, high-resolution, real-time picture of the way your dam was performing rather than relying on weeds, as-designed hopium or the blatherings of your PR spokesperson.

Laying a grid of 20 or so of these across a suspicious area shouldn't be that big of a deal to the dam operators. They could probably get a grant for a university and have it done for free, including slave labor. Is it lack of intellectual curiosity, or is there some other reason DWR wouldn't want this done at Oroville?

Has anyone ever instrumented a dam like this ER333, or is there an assumption that the phreatic line should be nearly vertical and too deep inside the dam to measure? I understand why they didn't bother doing this in 1965, but not doing it today on the tallest earth-fill dam here with 'issues' seems a little like depraved indifference.

Bravo for DWR managing a grand total of one monitoring well over what looks like a former erosion channel on the abutment to confirm their 'natural spring' theory, but really?

Maybe I'm oversimplifying this, but I don't see the need for a year-long project to install a thousand individual 300' deep monitoring wells on the downstream slope. Sinking a dozen or two drive-point piezometers into a grid on the hillside near the green spot would take a week. Two weeks if you use grad students because they're always late.

Either the water is there or it's not. If it's not, then DWR management can crow about their engineering genius. If it *IS* there, then maybe they could actually address the issue. Foisting it off on their PR spokesperson so the hostile crowd doesn't string them up on lampposts seems a bit... self-serving.