33 Cal. 3d 419, 189 Cal. Rptr. 346, 658 P.2d 709 (Cal. 1983)
National Audubon Society v. Superior Court, widely known as the Mono Lake case, is a cornerstone of California water law and environmental law.
Does the public trust doctrine restrict state-sanctioned diversions from non-navigable tributaries that degrade a navigable water body, and do courts have authority to require reconsideration of previously granted water rights and to provide interim protection while the State Water Resources Control Board exercises its primary jurisdiction?
Under the public trust doctrine, the state, as sovereign trustee, has a continuing, affirmative duty to protect navigable waters and their underlying beds for public uses, including navigation, commerce, fishing, ecological, recreational, and aesthetic values. The state may authorize appropriations of water, but it cannot abdicate its trust obligations; water rights are held subject to the trust and the constitutional reasonable use mandate (Cal. Const. art. X, § 2). Diversions from non-navigable tributaries that substantially impair navigable waters are subject to the public trust. Courts have concurrent jurisdiction to adjudicate public trust claims and provide interim relief, while the State Water Resources Control Board has primary jurisdiction to allocate water and to reconsider and modify existing rights to protect trust uses to the extent feasible.
Yes. The public trust doctrine applies to state-authorized diversions that reduce inflows to navigable Mono Lake, including diversions from non-navigable tributaries. The state retains a continuing duty to consider and protect trust uses and may reconsider and modify previously granted water rights where feasible to avoid or mitigate harm. Courts may hear public trust claims and issue interim protective orders, but should ordinarily stay proceedings to allow the State Water Resources Control Board to exercise its primary jurisdiction to reevaluate the relevant water rights.
National Audubon is the leading California authority integrating the public trust doctrine with the state's water law framework. It establishes that water rights—new and old—are subject to ongoing public trust oversight and the reasonable use mandate, and that diversions from tributaries are constrained when they impair navigable waters. The case is a blueprint for balancing environmental protection against consumptive use, clarifies court-agency coordination via primary jurisdiction, and has influenced later cases applying trust principles to other hydrologic contexts. For law students, it exemplifies how courts reconcile common law doctrines with complex regulatory systems and how public values can reshape long-standing property entitlements.