Interjurisdictional Boundaries in Tidal and Non-Tidal Rivers

This paper is concerned with the delimitation of inter-jurisdictional boundaries in tidal and non-tidal rivers. Inter-jurisdictional boundaries are defined, for the purpose of this paper to mean boundaries dividing public regimes as opposed to private interests. The paper addresses legal principles and describes survey methodologies used to cartographically depict such boundaries. Although inter-jurisdictional boundaries fall within the domain of public law, it is often necessary to resort to private law principles to interpret their statutory descriptions. Insofar as non-tidal rivers are concerned, the ad medium filum aquae rule is well founded in the common law. In contrast, the law with respect to tidal rivers is less clear. The paper attempts to shed some light on this subject by examining relevant legal authorities. The paper also describes delimitation methodologies and discusses issues such as mathematical computations versus graphical solutions, the importance of monumentation and the moving nature of unmonumented river boundaries.