I would appreciate an explanation of why it does not matter.
If I own some land with a lake on it and you own some land where waterfowl like to nest because of that lake. And, if I drain that lake thereby driving all your waterfowl to nest elsewhere, that's too bad. You can't tell me that I have to leave the lake intact just because it will change the wildlife on your land. It's my lake. I own it. Therefore, I have complete control over it. Your rights don't extend over into my rights. If the situation were reversed, you would have the same right to keep or destroy your lake and I would simply have to deal with the consequences.
You're wasting your breath, FirstAscent. We've already been through this - you'd have to sign a contract with him where you promise not to pollute the lake, and he promises to keep it in good condition. I never did understand what's to stop the guys upstream pissing in the river though (in *their* property). FredericBastiat did say, at least, that polluting someone else's property is equivalent to trespass though the issue seems far from resolved:
Does someone have to own the sea as well? And all the ocean? Do you have to enter into a contract with people on the other side of the ocean in the event your pollution should cause damage there?
If you don't own it, and I don't own it, and nobody owns it, then who cares. I know your answer. You do care; so go homestead it, occupy it and claim it for your own, and then complain at me when I provably pollute it (equivalent to trespass).