Ranger,
There are so many varieties. All I have experience with did not grow in water & did not even grow to the edge of water. It likes moist soil but also likes it's feet dry. There may be some that will I don't know. As I said earlier I won't plant it where I can't control it with a bush-hog. It can be invasive on land over a period of years. I'm sorry I can't comment on the amount of water intake or the litter. I'm still learning too.
Robert,
It can't be carried from pond to pond by birds, boats or whatever. It will only cause a problem if left neglected in suitable soils where your plant it.
Ric
