Notes on Rivers as Boundaries

Abstract

In the middle ages rivers which separated alien peoples or tribes were looked upon as neutral barriers rather than areas susceptible of nice division and capable of ownership. There gradually arose, however, a sense of the necessity for the assertion of control over such waters; but there was confusion of thought as to the nature and extent of that control. Rivers served as natural arteries of commerce as well as natural boundaries. The matter of navigation was of as great moment as that of territorial limits. For that reason, early writers announced the principle of co-dominion, which assigned to the opposite riparian proprietors rights of sovereignty over the entire stream. Men found it difficult to reconcile the claim of exclusive sovereignty asserted by one state over any portion of the stream, with the claim of another to exercise rights of navigation therein. No doubt the latter claim had a marked effect upon the scope of the former. Nevertheless, rights of navigation were not decisive of the problem whether a line of division might be drawn through the waters of a river in recognition of exclusive sovereign rights of the states on either side thereof. It came to be understood that such a line could be drawn. In accordance with the views of Grotius and Vattel, nations were agreed that it should pass through the middle of the stream. This method of division proved, however, to be unsatisfactory in the case of navigable rivers; for, in disregarding the course of the principal channel, it was likewise heedless of the equities of the state that happened to be the more remote therefrom. Nor did it adapt itself to gradual changes which such channel might undergo. As a result, at the beginning of the nineteenth century, riparian states began to conclude treaties which proposed a different method of division and which has since become the accepted mode of indicating the frontier.