Enjoy Me Now, I may not make it back...

I'm going to go white water rafting on the Lochsa this weekend. They sent me a check list and it pretty much said write your will, because your going to die.

I was hoping to take care of  some of my Lay Off List  care of specifically #3. Now I'm worried that I won't ever finish my list...

I'm not afraid of water, I can swim like fish. I am a swim teacher for god sakes, but I am scared of head injuries. I have a huge head and it is always the first thing to hit. This explains my varied past full of concussions. 

Any survival suggestions?