If you do not want to get in the water, no problem but I do not see an issue code wise about running it under the walk way. It looks to be above the water anyway in your picture but there is no code reason why it can't be underwater if it had to be. It is still a wet location.
I do agree with Reno, PVC will never look great if you have to look at it but those PVC 2 hole straps do not hold up. I would use something else.

Call the AHJ and ask what he wants to see. This can't be the only dock they have wired around there.


Greg Fretwell