Earlier quoted context omitted.
Which makes sense because water flows underground.
It also makes it impossible for someone to decide ex ante if their property is a wetland, a problem with the current process SCOTUS called out. Namely, the government wouldn’t tell you if your property was a wetland until after it thought you’d violated the law.
I can look up a map of what the State and Federal government consider a wetland on my property. If I need to do eg construction within 100 feet of such an area on the map, I'm supposed to call in the local DEC and they -- for free -- come in and tell me the boundaries of the wetland based on local vegetation.
Isn't that how it works everywhere?