Well, if there isn't a log and I don't have any spare footwear or a pair I'm willing to get wet, I just roll through it barefoot. A little slippery sometimes, but all the more reason for my to take my time.

I used to bring along a pair of shoes just for that purpose that I didn't care would get wet and just change into them at crossings. Nowadays I bring along my Merrel water shoes I bought since they tend to be work just fine to walk in, water or not, if I were to get tired of my boots.