## Facts

- Mono Lake is a saline, closed-basin, navigable lake whose tributary inflows support significant bird habitat and related scenic and recreational uses.
- Beginning in 1940, California agencies issued permits allowing the City of Los Angeles Department of Water and Power (LADWP) to appropriate and divert virtually the entire flows of four Mono Lake tributaries into the Owens Valley aqueduct system.
- By the 1970s, LADWP was diverting nearly all tributary flows, contributing to a substantial decline in lake level and surface area, increased ecological stress, and threats to nesting birds due to changed island conditions.
- In 1979, the National Audubon Society, the Mono Lake Committee, and others sued in superior court to enjoin the diversions, alleging violations of the public trust doctrine.
- The Alpine County Superior Court ruled that the public trust doctrine was absorbed into the statutory appropriative water rights system and that plaintiffs were required to exhaust administrative remedies before the State Water Resources Control Board (Board).
- Petitioners sought an original writ in the California Supreme Court to set aside those rulings and clarify the relationship between the public trust doctrine and California water rights law.

## Issues

1. Whether the public trust doctrine operates as an independent limitation on California’s appropriative water rights system when diversions harm a navigable waterbody’s trust uses.
2. Whether previously granted appropriative rights remain subject to continuing state supervision and modification to avoid or reduce harm to public trust resources where feasible.
3. Whether plaintiffs must exhaust administrative remedies before the Board, or whether courts have jurisdiction to adjudicate public trust claims alongside administrative processes.

## Decision

- The California Supreme Court issued a writ directing the superior court to vacate its rulings that the public trust doctrine was subsumed by the statutory system and that plaintiffs were barred by an exhaustion requirement as imposed by the superior court.
- The court held that the public trust doctrine remains an independent constraint on water allocation decisions and limits appropriative water rights.
- The court held that appropriative rights are held subject to continuing state authority to reconsider and, when appropriate, modify past allocations to protect public trust uses.
- The court recognized that water supply needs may justify diversions that cause some environmental harm, but decision-makers must seek feasible means to avoid or reduce harm to trust uses.
- The court held that the Board has primary responsibility for technical and allocation determinations, while courts retain authority to adjudicate public trust claims and review or compel agency action.

## Legal Principles

- The state holds navigable waters and their beds in trust for the public and retains continuing supervisory control to prevent substantial impairment of trust uses.
- The public trust doctrine extends beyond navigation, commerce, and fishing to include protection of scenic, recreational, and ecological values in navigable waters.
- Appropriative water rights are acquired and exercised subject to the public trust; statutory water allocation schemes do not displace the trust duty.
- Previously issued water rights and permits may be reconsidered and adjusted when necessary to protect public trust resources, based on current information and conditions.
- Public trust protection requires a balancing of competing needs; diversions may proceed if decision-makers pursue feasible measures to minimize harm to trust resources.
- The Board and courts have concurrent roles: the Board is the principal forum for allocation and permit modification, and courts may enforce public trust duties through adjudication and judicial review.

## Conclusion

The court integrated the public trust doctrine into California water law by holding that trust duties independently limit appropriative rights and impose an ongoing obligation to protect navigable waters’ ecological and recreational uses when feasible, with enforcement shared between administrative and judicial institutions.


National Audubon Soc'y v. Superior Ct., 33 Cal. 3d 419, 658 P.2d 709 (Cal. 1983)