"FOC" (First Overflow Channel)

Depending upon which gates on the dam are open/releasing, there may be different options available for whitewater play. A decent-sized island splits the overflow ('non-power-generating') channel, and another larger island divides this area from the outflow of the Xcel Energy Hydro plant. It may be possible to explore some combination of channels.
The "First (rightmost) Overflow Channel" will be the easiest to explore, since you will be parking and accessing the river from that side.
Exploring any other channels will require being able to land and carry up on any of these islands.
Some great drone-video, at a time of very-high flow, is available at: https://youtu.be/yZxq_EowoC8(I've cued the link to cut out the first 1:40 of video of the drone taking off and flying to the channels.)