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.
I agree with you on "head" reservoir levels and a corresponding "flow" rate. Essentially, there is much information that should be swiftly determined regarding this issue at the dam as there is likely more "internal" factors in the dam at play that may be "unseen" (per the prior discussion of the metric of Green Area surface observations).
I believe this issue will now become forefront with the public. Documents now establish that DWR (and indirectly FERC) are tied to a disaster potential liability that would be sustained in a court of law - if anything were to occur - from this form of "negligent" inaction (based on evidence of such a high potential risk factor).
Because of the "unknowns" (i.e. greater flows "unseen") and the resilience of the Wet area even in hot dry drought conditions, there is strong evidence there is something larger at play. This fact alone may force the question - Should the dam be only allowed to operate below this "wet area"? Or more harsh, Without the ability to assess the structural stability of the internal state of the dam with zero function safety device sensory Piezometers, should the dam be lowered to a level to "make safe" for the structural lower part of the dam to insure a safety margin?
There are other dams that are operating under these exact lower reservoir level limitations due to issues related to insuring a "safety margin".
Oroville dam's release capacity at the Hyatt power plant is the problem. The dam can't keep up with high levels of inflow. Thus, to insure that the dam does not exceed the "leakage area", does that mean the reservoir level has to be far lower to account for an inflow? (this could effectively force the dam to operate with extremely low levels in this case).
No easy answers right now.
The August 1, 1975 Oroville earthquake investigations
by California. Dept. of Water Resources
Published 1979
https://archive.org/details/august11975orovi20378cali