Fasinating ,the Nigra falls power is the generater for the Flight locks ,absolutely amazing if you ever go over ,I sailed on two specific Lakers ,right up to Deluth ,I was gobsmacked to know that where we got to the trappers took their furs many years ago ,very interesting place ,and the fresh water that is the Lakes is lovely to drink .As I said I was up there in the first convoy in 1965 ,freezing .