## Facts

- John Crowley held a prior, adjudicated appropriation of Madison River water for irrigation and used an established diversion system (wing dam and ditches).
- Crowley sued Montana Power Company and others for damages, alleging dam operations interfered with his irrigation supply in 1935, 1936, and 1937.
- The amended complaint pleaded nine causes of action, grouped into three theories by year.
- The second group (causes 2, 5, and 8) alleged defendants impounded the river’s natural flow so the water surface at Crowley’s diversion point was too low for his reasonably adequate, long-established diversion works to divert water.
- The second group further alleged Crowley could access water only by making large expenditures to build a new diversion system capable of diverting the reduced flow.
- The district court sustained general demurrers to the second group but overruled demurrers to the first and third groups.
- Crowley sought an original writ proceeding requesting supervisory control to require the district court to vacate its ruling and overrule the demurrers to causes 2, 5, and 8.

## Issues

1. Whether causes of action alleging that a junior user’s dam operations lowered the river level so a senior appropriator could not divert water through reasonably adequate existing works, absent costly reconstruction, state a claim for actionable interference with a prior water right.
2. Whether supervisory control is an appropriate remedy to correct the district court’s sustaining of general demurrers to those causes of action.

## Decision

- The Montana Supreme Court granted supervisory control and ordered the district court to revoke its order sustaining the demurrers to causes 2, 5, and 8 and to overrule those demurrers.
- The Court held the second-group allegations stated a legally sufficient claim for interference with Crowley’s prior appropriative right, even if some water continued to pass downstream.
- The Court overruled respondents’ motion to quash and dismiss the original proceeding.
- Justice Morris dissented.

## Legal Principles

- A senior appropriator states a claim for interference when a junior user’s operations materially change stream conditions so that the senior cannot make beneficial use through reasonably adequate, established diversion works.
- The existence of some downstream flow does not defeat a claim if the water is rendered practically unavailable at the senior’s point of diversion due to the junior’s impoundment or operational practices.
- A senior appropriator is not required, as a matter of law, to undertake large capital expenditures to reconstruct diversion facilities to accommodate stream-level changes caused by a junior user.
- Supervisory control may be used to correct significant legal error at the pleading stage when ordinary appellate remedies are inadequate to prevent improper truncation of claims.

## Conclusion

The court required the district court to reinstate Crowley’s demurred causes of action, holding that a senior water right is infringed when a junior dam operator lowers the river level so the senior’s reasonably adequate existing diversion cannot access the water without substantial reconstruction, and that supervisory control was appropriate to correct the pleading-stage error.


State ex rel. Crowley v. District Court, 108 Mont. 89, 88 P.2d 23 (Mont. 1939)