Swimming

I was swimming back from Seattle, on the river that runs to Wenatchee.  It was a broad, deep river, and the current wasn't very strong.  Eventually, I came to a water fall.  It was a rather large waterfall, at least 1000 ft, and there was a huge pool at the bottom.  I got onto the diving board, and prepared to jump.  The bottom was a mere blur, obscured by the vast distance.  I readied myself, and jumped.
As I fell, I realized that there was a pontoon in my way, with people on it.  I tried to move, so as to not hit it, and destroy it, but it kept moving to match my movements.  I was forced to slow myself, almost to a stop.  Eventually, I evaded it, and landed in the pool.  I decided I was done with swimming for a while, and got out of the pool, and went into the men's changing area, that was carved into the cliff face.  Though it was in a cave, all of the walls were made of wood.  I got changed, and walked into a room with lots of people in it, from my past.