Muddying the Waters: Sixty-One Years of Doctrinal Uncertainty in Montana Water Law

Abstract

The development of water law in the western United States is a valuable case study in the refinement and abrogation of the common law in the face of customary practices and their comparative suitability to the climactic and institutional conditions in the arid West. These conditions frequently meant the prevailing water doctrine became prior appropriation, a change which required the abrogation of the common law riparian doctrine. The development of Montana’s water rights regime over sixty-one years provides an extended context through which to view the iterative process by which this change occurred. Unlike a number of other western states that confronted this legal dilemma, Montana did not clearly adopt the prior appropriation doctrine, which meant the Supreme Court of Montana, in keeping with the canons of judicial deference and avoidance of legal conflict, had to reconcile conflicting statutory requirements regarding riparian and prior appropriative rights over six decades. In resolving cases in a manner faithful to statutory requirements, equitable resolution for the interests of the participants, and avoidance of legal conflict, the Court slowly removed components of the riparian doctrine until prior appropriation was the de facto law of the land. Our survey of the extended judicial development of Montana’s water rights regime emphasizes the lessons that unclear statutes can have enduring consequences, judicial reconciliation of conflicting law can ultimately rewrite the law itself, and scarcity drives changes in property rights that can be determined in part by the coordinative choices of those subject to the legal ambiguity itself.

Keywords: Property Rights, Property Law, Private Ordering, Water Rights, Prior Appropriation, Common law, Riparian, Legal Conflict, Legal Ambiguity, Judicial Interpretation, Law and Economics

JEL Classification: H79, K11, K49, N51, N91, O13