This makes no sense to me at all, so I wonder if either the paper is misreading the law, or (probably just as likely) this is the law, however inane it may be. Ephermeral streams are a nearly constant prescence in a mountainous area, with little ones down every hollow on ridge-slope. Such a law would exclude human prescence from most of the mountains- probably the goal, aye?
IMO the press is incapable of reporting accurately on any legal issue more complicated than a jury saying guilty or not guilty.