Hi again, Ron,
The comments and advice from Andre and Jerry are excellent.
A few additional observations based on a lot of experience there:
1. Take the information from the telephone 'hotline' with a bag of salt. They purport to give, in a recording made at 5 p.m., the power generation schedule for the following day. Some times they stick to it; others they don't. The demands of the electric grid may demand changes in their announced schedule, and all bets are off. Of course, when they open some dam gates, fish go through and don't survive, and become the floaters that eagles, herons and cormorants grab. The more 'units' of power they generate, the better for photographers.
2. Want an eagle to swoop down in front of you and offer the photo of a lifetime? Take a lunch break, a porta-potty break, get involved in a real good conversation, or engage in some 'chimping.' :bg3: That brings the eagles every time.
3. Seriously, it pays to pay attention to the water, and not the (especially on weekends) mob scene distractions along the fence. Regulars know what I mean.
4. While the 'peak' can be late November to late December, eagles are there most every day. You may not see them, but they're present, often hidden in the trees on the hills in back of the parking lot. They can dive to the water right in front of you, with zero lead time. Thus the importance of watching the water as much as you can stand to do so.
5. Also, as noted above, be sure to change your camera settings as you go from river shots to flight shots. I've goofed on that one more times than I wish to recall.
6. Even on non-peak 'slow' days, you can get some good photos. Here's one I got last Monday, very late in a very dull day, devoid of action until then.
Have a great time when you go, Ron !