Follow-up: The “security weakness” is real. (1) They should enhance security access routes to the dam (military grade security to stop kinetic vehicular breach attempts). (2) they should consider backup power only operation for MS (layer of redundancy).
I think I understand what you mean. And if it is what I’m thinking, it’s not the only place that it could happen. But the results would be pretty significant at this location.
As far as the spillway gates, if it’s like the dams (well, some of our dams) in the TVA system, they have on-site diesel generators specifically for the purpose of allowing starting the plant in a total blackout situation. I’m not sure about gate operation under those conditions, but many of our dams have a crane-rack type of mechanism that is moved from gate to gate to open or close the individual gates. A semi-manual operation, but it still requires power. I honestly don’t know if they are set up to operate with the diesel as the only power source or not, but I suspect that that can be done.
If I think of it, I’ll ask one of the hydro operators on Monday. They would know.
Here’s a quick video of the Chickamauga Dam near Chattanooga, TN, with some of the spill gates opened. This is about 10 miles from my house, and I have been deep inside of it. Incidentally, there’s a bit of water seepage inside, but it’s apparently considered “normal” and according to old timers, has been like that as long as they remember.
https://www.youtube.com/watch?v=Q0Rn7G8CRUg