## Facts

- A ditch-and-tunnel system constructed in the early 1900s diverted water from windward Oʻahu streams and connected groundwater to leeward Oʻahu for plantation agriculture.
- The diversions reduced windward stream flows and affected ecological conditions and community uses associated with the Kāneʻohe Bay watershed.
- After the end of major sugar operations in 1993, multiple parties asserted competing claims to continued or increased offstream diversions, including agricultural interests and municipal suppliers.
- Windward community, Native Hawaiian, and environmental parties sought restoration of instream flows and protection of traditional and customary practices dependent on stream conditions.
- The Commission on Water Resource Management conducted a consolidated contested case under the Hawaiʻi Water Code addressing (1) water use permits for offstream diversions, (2) amendments to interim instream flow standards, and (3) petitions for water reservations.
- The Commission issued a final decision allocating water among instream and offstream uses, revising certain interim instream flow standards, and addressing claimed “system losses” and certain well-permit matters.
- Multiple parties appealed, challenging both the Commission’s legal framework and specific findings and allocations.

## Issues

1. Whether and how Hawaiʻi’s constitutional public trust doctrine governs allocation and permitting of surface and groundwater in the Waiāhole system.
2. What burdens of proof and decision standards apply to offstream diverters and to the Commission when setting interim instream flow standards and allocating water amid scientific uncertainty.
3. Whether the Commission’s specific determinations (including interim instream flow standards, offstream permits, treatment of “system losses,” and certain well-permit actions) satisfied constitutional and statutory requirements and were supported by adequate findings.

## Decision

- The Hawaiʻi Supreme Court affirmed in part, reversed in part, and vacated and remanded in part the Commission’s decision and order.
- The court held that Hawaiʻi’s fresh waters, including connected surface and groundwater, are public trust resources held by the State for the benefit of the people.
- The court approved the Commission’s general recognition that protection of public trust resources is a precondition to other allocation decisions, and treated that priority as a constitutional obligation.
- The court required a heightened showing by offstream users seeking to divert public trust water and directed the Commission to apply a protective, precautionary approach where information about impacts is incomplete.
- The court remanded for reconsideration and improved findings on several matters, including justification of interim instream flow standards, scrutiny of certain offstream allocations, and quantification and minimization of claimed “system losses,” as well as related well-permit issues.

## Legal Principles

- The State holds waters of the State in a constitutional public trust; private and permitted uses are qualified by ongoing trust limitations.
- The Commission, as trustee, has an affirmative duty to investigate, evaluate, and protect public trust purposes; it is not limited to resolving disputes among private claimants.
- Public trust purposes include, at minimum, ecological integrity and maintenance of waters, traditional and customary Native Hawaiian practices, appurtenant and riparian interests, and public recreational and related values.
- Offstream applicants bear a heightened burden to prove their proposed use is reasonable and beneficial, that practicable alternatives have been considered, and that the diversion will not unduly impair public trust uses, including instream values.
- When science is uncertain or data are incomplete, the Commission must resolve doubt in favor of protecting the resource and public trust uses rather than allowing diversions by default.
- Interim instream flow standards must be developed and refined using the best information reasonably available and may not rest on historically depressed, diversion-era conditions without adequate justification.
- Statutory standards in the Water Code must be construed consistently with the constitutional public trust; statutory permitting cannot authorize impairment of trust purposes.

## Conclusion

The court treated Hawaiʻi water allocation as a constitutional trust function requiring priority protection of instream and other public trust uses, imposed a heightened justification requirement on offstream diverters, and required precaution in the face of uncertainty; it therefore upheld parts of the Commission’s order but vacated and remanded multiple allocations and findings for stricter application of these duties.


In re Water Use Permit Applications (Waiāhole Ditch), 94 Haw. 97, 9 P.3d 409 (Haw. 2000)