Hi jpal, Query: Where have these 3 design concepts been proposed? Are these early designs that have been released by DWR engineers? Or are they from discussions?
Your insight in the description of the situation is accurate to the engineering challenges they face. I would add that there are additional dimensions to the choices & difficult tradeoffs that are faced. If you were to create a cross-matrix array of the interdependencies of design, funding, politics, time crunch, and the "hand of God via nature - weather", you would end up with a dynamic project that must be adaptable.
On one hand, they must protect the public from catastrophic event(s) - thus the need to emergency repair & armor the Emergency Spillway as there is an unknown to the integrity of the upper main spillway's health.
On the other hand, they must plan for the ultimate restoration to adequate safety factor ratings to the Maximum Probable Flood levels. How they get there from now to the ultimate restoration almost assuredly requires flexibility in interim options.
I wouldn't be at all surprised if an option develops where a "flip" is used to a secondary lower spillway where the secondary lower spillway is built to dissipate the "capture" of the lift and transport it to another form of a dissipation block system @ the Feather river.
In any case, keep the wheels turning... we'll see what is going to be proposed soon. Let's hope the hand of God in Nature will be amenable (for the sake of many below the dam).
and Keep posting...
A question if you please.
It would appear that the upper portion of the spill way is compromised, most likely fatally, but the DWR is pretty much stuck with it for the foreseeable future.
I have seen on highway overpasses here in KC where the DOT has placed an epoxy coating on the roadway. This coating has been in place for at least 5 years and seems to be holding up rather well. I would guess that this process could be done rather quickly and given the massive amounts of money already spent fairly cheaply:-)
In your opinion do you think this would work as a sealant to stop/reduce water infiltration through the spill way?
Regards
alfa6 ;>}