here is the thing just because property is behind your house doesn't mean it belongs to you.
According to the federal navigability laws , which the states have no right to supercede, all water ways that can be floated in a boat are navigable and therefore public property held in trust by the states expressly for public use.. up to the normal high water mark.

That is the federal law that the states have no right to supercede. However they supercede it all the time..