Few functions of the American Federal system seem less suited physically to state boundaries than the management of our water resources. The reason is readily apparent. Water flows according to drainage districts and not the riverbounded or rectilinear areas of the American states. Nevertheless, it takes more than topography to delineate the states or provinces of a nation; there are historical and constitutional factors to consider. Once provincial areas are established as states under a national constitution, and, such functions as water supply are assigned to these states, it is not only difficult but it may also be disruptive to withdraw such a function from them, even though physical facts and technological changes cry for this solution.