## Facts

- In spring 2008, juvenile salmonids in the Russian River stream system were found fatally stranded after rapid water-level drops during frost events in a dry year.
- Fisheries scientists attributed the stranding to simultaneous, high-rate frost-protection pumping that drained streams and sprayed water on vineyards and orchards.
- The State Water Resources Control Board adopted California Code of Regulations, title 23, section 862 (Regulation 862) to address frost-protection diversions in the Russian River watershed.
- Regulation 862 required Water Demand Management Programs (WDMPs) administered locally and approved by the Board to coordinate frost diversions.
- The regulation declared frost-protection diversions “an unreasonable use of water” unless conducted in compliance with a Board-approved WDMP.
- The regulation applied to riparian users and pre-1914 appropriators, groups generally outside the Board’s ordinary permitting scheme.
- Riparian landowners and other growers challenged the regulation as an unlawful, permit-like constraint that altered seniority and delegated Board authority.
- The trial court invalidated Regulation 862 on grounds including lack of Board authority, violation of priority, improper delegation, and insufficient evidentiary support.

## Issues

1. Whether the Board may regulate unreasonable use and unreasonable methods of diversion by riparian and pre-1914 appropriative right holders through Regulation 862.
2. Whether Regulation 862 unlawfully нарушes the rule of priority among water right holders.
3. Whether requiring locally administered WDMPs constitutes an unlawful delegation of the Board’s regulatory authority.
4. Whether substantial evidence supported the Board’s finding that unmanaged frost-protection diversions posed a threat to salmonids warranting the regulation.

## Decision

- The Court of Appeal reversed the judgment invalidating Regulation 862 and upheld the regulation in major part.
- The court held the Board has constitutional and statutory authority to regulate unreasonable use and unreasonable methods of diversion by all classes of right holders, including riparian users and pre-1914 appropriators.
- The court held Regulation 862 did not violate the rule of priority because priority governs allocation among lawful uses and does not authorize unreasonable diversion methods.
- The court held the WDMP framework was not an unlawful delegation because programs require Board approval and remain subject to Board control and enforcement.
- The court held the administrative record contained substantial evidence that uncoordinated frost-protection pumping could cause abrupt flow reductions that strand juvenile salmonids and that coordinated management could mitigate the harm.

## Legal Principles

- California Constitution article X, section 2 limits all water rights—riparian and appropriative alike—by prohibiting waste and “unreasonable use” and “unreasonable method of diversion.”
- The Board’s authority to prevent unreasonable use is not confined to the statutory permitting system and may reach riparian and pre-1914 uses when the method of diversion is unreasonable.
- The rule of priority does not protect any user, regardless of seniority, in engaging in an unreasonable use or unreasonable method of diversion; seniority operates within the bounds of constitutional reasonableness.
- Public trust considerations, including protection of fish and wildlife habitat, may be weighed in determining whether a use or method of diversion is reasonable.
- A regulatory scheme using local entities to develop management programs is permissible when the agency retains final approval, oversight, and enforcement authority, and the local role is implementation rather than independent lawmaking.
- Substantial evidence review sustains an agency regulation when the record reasonably supports the agency’s predictive and scientific judgments about harm prevention and workable mitigation measures.

## Conclusion

The court held that Regulation 862 validly applied the constitutional reasonable-use limitation to frost-protection diversions by riparian and pre-1914 right holders, did not disrupt priority rules, permissibly used Board-approved local WDMPs, and was supported by substantial evidence of harm to salmonids from abrupt, coordinated pumping.


Light v. State Water Res. Control Bd., 226 Cal. App. 4th 1463 (Cal. Ct. App. 2014)