I have only lost one anchor in the clinch and it was during a spilling episode, right above the jail. I dropped anchor to help net a fish, and the current wouldn't allow it to catch until it wedged in cut in one of the ledges. It **** near yanked us out of the boat. The solution was easy in a drift boat, I simply released the anchor catch and let all the rope feed out. Went back a week later and got everything back.
I would not recommend anchoring on spilling water levels or sluicing water levels. However, I have never had issues with 2 generator flows, and do it routinely when I am out on those flows.
If you are smart about it, and know the warning signs of a dangerous situation it is very easy to either cut the rope or let it slip through to avoid getting dumped.