What do a Roman Emperor, the Magna Carta and the Northwest Land Ordinance have to do with the Cannon River and its classification under Minnesota’s Wild and Scenic River Act? They all have ties to the Public Trust Doctrine—one of the major reasons why rivers and lakes cannot be privately owned.  The Public Trust Doctrine is a national doctrine that cannot be changed by individual states.  The basic premise of it is that any navigable waterway is ‘held in trust’ by the states for the public.