Hi Dan, I like the composition a great deal and think the top third works very well to provide depth and context.
Did you try a print with slightly less contrast? Although I like the strength of the contrast you have I would love to see a little bit of detail on the tidal flat behind the S puddle.
I think it can be cropped either way, but keeping the top third gives a sense of scale. I like the contrast level, never be afraid of the dark. Very nice.