According to the state of Idaho, there are exactly two waterfalls of any size in the entire state that have not been diverted for irrigation (I learned this the hard way back in 1977, when I made my way down a treacherous and lousy road to see the supposed "200-foot-high Shoshone Falls of the Snake River," only to discover a dam across the top of a dry cliff). Here they are.
Lower Mesa Falls, seen from the viewpoint along the official scenic highway through the national forest.
Upper Mesa Falls, seen from a small Forest Service park that for some reason charges three bucks "parking" fee (not that there's any way you could get to this place without having to park a vehicle). I committed a mild act of Civil Disobedience upon leaving this little park, handing my "parking pass" to another rider who was on his way in.
Don't tell the Feds...