Confluence was never closed.
What your friend is confused by is a closed sign put on the foot bridge just before Confluence.....but it didn't refer to Confluence Park.
They have been working on putting in another foot bridge about 1/4 mile below Confluence Park. The pushed some gravel in the river bank, changed the river flow a little, and to cover their ass, they declared the river closed at that point. They did this a little more than a year ago. Then a flood washed out their gravel pile so they delayed construction for a year--the whole time keeping the closed sign up.
And we wonder why government instructions don't have much credibility........
900 cfs is a bit much for confluence park. It may be washed out. Some of the drops for the 1/2 mile below confluence may be real good. There is a tressle bridge about 3/4 of a mile below confluence which gets a real good wave at this level.
Enjoy, and don't believe all the hype about the poison water at confluence. It's only a true a small amount.