Water gets really complicated, legally, going back to the Romans. Water being on your property doesn’t really mean much. Imagine if you were allowed to buy 100 feet next to a river and damn it, for example.
Curses and hexes are not prohibited by the law. If you want to damn a river, damn it. You don't even need to buy the land first.
to those who say "it's better to light one candle than to curse the darkness" I say "Damn the darkness!"