Paul :

I was hoping someone else would give their advice. Maybe they will yet.

I have used Roundup on small areas around the ponds once or twice. I would not use it much or often around the pond edge. That does not mean it is unsafe or that others don't use it. If I were going to spray around more than a small area around the pond with glyphosate I would use one that was approved for water use. See this link for several.

http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=14;t=000247