I'm not a Libertarian, but as Revoltingest would say, the upstream neighbor is swinging on the downstream neighbor's nose, which violates the "my rights end where you nose begins" thingy he says. And, indeed, many Libertarians do support a similar mindset, but it's also true that many don't.
Wags will say that libertarians oppose all regulation, but
is this just a straw man? Perhaps they believe that libertarians
are anarchists who oppose all regulation & even government.
If that were so, we'd call ourselves "anarchists"
Maximizing social & economic liberty means establishing boundaries
such that crossing them begins to harm others. This is better than
anarchy, wherein on has no redress of grievances except for personal
action against the transgressor. We know that can turn violent.
To such wags, I ask....
Which libertarians oppose such useful environmental regulation?
Name & quote them, & I'll address their claims.