I encourage your insightful queries, discussion, and skilled technical abilities. In these FReeper discussions, and in decades of complex failure analysis, I have found the best input from great souls such as these discussions have yielded. No need for disclaimers here (degree/expertise/etc) & no questions/comments should be inhibited by such. btw- often times, it is a technician or some other person who notices something unusual, yet crucial to the failure investigation, that experts (some not all) have discounted. That is why I will interview the tech’s after getting the initial failure crisis challenge explained by the experts.
I don’t know my amphibolite from a hole in the ground!!!
1. All of the remaining spillway is damaged or undermined beyond repair. There is just too much bad construction and damage to be sure that a patch job will not fail in the future.
2. I am very concerned about the main spillway gate structure. There is some limited information that it is weeping more than expected or designed to.
3. The e spill is a joke and needs to be seriously evaluated and dealt with.
I think the prudent course of action is the construct a new spillway - including a gate structure - adjacent to the existing one using modern techniques and design. This would allow the project to go through another wet cycle using the damaged system, in the meantime, if needed. Caisson pier system and pressure grouting the “bedrock” down to a 100 feet of so would stabilize the area significantly. Modern rebar specifications and concrete technology. They are not going to catch any breaks on this situation. The geology and past sins are an too big of a hill to climb