I fished (from shore)the Hidden Falls side of the river to the dam for a couple hours yesterday and was skunked. I was there mid morning until noon and only tried jig and plastics. A different time of day and different presentation might make all the difference.
You can walk out to the confluence from the Ft. Snelling area but it’s a pretty good hike. I only tried it once last year without success, but that doesn’t mean it’s not good to try! Please report back.