Not if you install a good apron.
Good examples of apron installation, tho I'd not recommend 1/2" HC...go with 14ga 1x2 or 1x1, will hold up much longer and is easier to lay flat.
http://www.backyardchickens.com/t/1110498/wire-around-coop#post_17093528...
They do need a landing area.
Best to put roosts as low as possible, but above other things.
Here's some tips:
https://www.backyardchickens.com/articles/coop-stack-up-how-high-should-stuff-be.73427/
As to your watery world, make sure the coop and run doesn't flood from surrounding run off...