## Facts

- Multiple irrigation districts, water companies, and landowners used surface flows and groundwater in the Kaweah River delta for irrigation and related needs.
- The Kaweah River entered an alluvial “delta” where surface diversions and irrigation return flows affected groundwater conditions; the dispute involved both river flows and a connected underground basin.
- An irrigation district located outside the Kaweah watershed planned to install large-scale wells in the delta, pump groundwater, and transport it out of the basin for use on lands within its own district.
- Delta users alleged the pumping-and-export plan would reduce the common supply supporting their established riparian and appropriative uses and would worsen existing shortages.
- Evidence showed the exporting district’s member lands practiced heavy winter flood-irrigation that was substantially motivated by pest control (e.g., gophers), with uncertain agronomic benefit and high water consumption.
- The trial court quieted title in favor of the delta users, enjoined the exporting district from pumping and exporting groundwater, and limited its surface diversions to water needed for riparian use on its riparian lands within the delta.
- The exporting district appealed, challenging the legal treatment of groundwater, the reasonable-use analysis, and the scope of injunctive relief.

## Issues

1. Whether groundwater within a defined basin that is hydraulically connected to a surface stream may be treated as part of a common supply protected by existing water-right holders.
2. Whether a junior user may pump and export groundwater out of the basin when doing so materially impairs established in-basin riparian and appropriative uses.
3. Whether asserted uses (including heavy winter flood-irrigation primarily for pest control) are limited by the requirement that water be put to reasonable and beneficial use.
4. Whether an injunction barring pumping/export and restricting surface diversions to riparian needs on in-basin riparian lands was proper in scope.

## Decision

- The Supreme Court of California affirmed the judgment in favor of the delta users, with modifications to conform the decree to the evidence and constitutional reasonable-use limits.
- The court held that the connected groundwater in the delta constituted part of a common source of supply supporting the river system and dependent users.
- The court upheld injunctive relief preventing the exporting district from pumping groundwater for transport out of the basin where such pumping would materially impair existing users’ rights.
- The court sustained findings that the exporting district’s winter flood-irrigation, justified largely as pest control with uncertain crop-related benefit, exceeded reasonable and beneficial use when it contributed to shortages and harmed other lawful users.
- The court approved limiting the exporting district’s surface diversions to amounts required for riparian purposes on its riparian lands within the delta.

## Legal Principles

- Groundwater in a defined basin that is hydraulically connected to a surface stream may be treated, for rights and remedies, as part of a single common water supply rather than as wholly separate “percolating” water.
- Both riparian and appropriative rights are subject to a continuing limitation that water use must be reasonable and beneficial; waste and unreasonable use are not protected even if a claimed right is otherwise valid.
- A junior appropriator may be enjoined from pumping or exporting water when the activity materially and substantially impairs senior riparian or appropriative users drawing from the same common supply.
- Water export from a basin is permissible only if consistent with reasonable use and noninjury to existing lawful users; otherwise, equitable relief may bar export.
- Injunctive relief in water disputes must be tailored to protect established rights while preventing waste and restraining uses found unreasonable under the governing standard.

## Conclusion

The court treated hydraulically connected groundwater and surface water in the Kaweah delta as a common supply and affirmed broad equitable protection for established in-basin users, holding that junior pumping and export—and water-intensive practices lacking sufficient beneficial justification—may be enjoined when they cause material injury and constitute unreasonable use.


Tulare Irrigation Dist. v. Lindsay-Strathmore Irrigation Dist., 3 Cal. 2d 489, 45 P.2d 972 (Cal. 1935)