I have floated / fished this river hard for the last 10 years, what you saw is not rare but also tough to witness, do not expect action every time you go out. The other day I lost count at about 40 goldeye they were taking streamers, dries, nymphs whatever you threw. The next day I floated the same area same conditions and caught nada. Goldeye are out now.
I have not heard of too many big brown being caught since the flood, my numbers have been down somewhat and so have the sizes. I curious how Jenzen is fairing this year, I have only seen him once.
Before the flood we were averaging 22" to 24" with none being under 20". Now I have not caught one over 20" this is a good thing I believe though.
Im at the dam most Thursday and Sunday nights 9 or so to catch the late hatch and yes I know of the bruisers you speak of, I have caught a couple over the years but its about a 25% catch ratio. Ive hooked them several times but 5X Fluro carbon is not match for a +25" reddeer brown. They seem to be a lot more wary then the bow river fish.
I have witnessed the catch of one nice rainbow at the dam and only one. They are there but you will not find this to be a regular catch.
The only tip I can give people at the dam...DO NOT GO IN THE WATER.... you will spook them for the night even if you think you are being cat-like. I remember a couple guys standing up to their chests and after getting skunked watching us catch fish they still didnt believe us.
They were from Calgary and fished it like the bow.