Pergolas are what I plan to do over my ponds as well. I am going to use grape vines, I have a friend who has had these for years over his pond. They grow fast and provide shade and fruit. You can cut them back and they will fill in every spring.
I heard of a vineyard in Cal. that thought it was wild turkeys that were eating the grapes. They set up a camera to monitor the vines and saw that it actually was raccoons that did the majority of damage.