## Facts

- Multiple parties, including the City of Fort Collins and private landowners, sought decrees changing points of diversion from the Cache la Poudre River.
- Existing ditch, reservoir, and municipal appropriators opposed the changes, alleging potential injury to their vested rights.
- Two distinct requests were litigated:
  - Jackson Ditch phase: Fort Collins had contracts to purchase 3.2 c.f.s. associated with Priority No. 3 (June 10, 1861) historically delivered through the Jackson (formerly Dry Creek) Ditch.
  - Coy Ditch phase: landowners held a decree for 16 c.f.s. (June 9, 1881) through the Coy Ditch; Fort Collins contracted to acquire 8 c.f.s. and sought an upstream diversion for municipal use.
- Prior litigation had adjudicated the nature and extent of rights of users receiving Jackson/Dry Creek Ditch water “without charge,” treating them as contract-based consumers rather than owners of an independent appropriative right.
- Evidence showed no more than 8 c.f.s. of the Coy Ditch’s decreed 16 c.f.s. had ever been applied to beneficial use on the relevant lands.
- The district court denied the Jackson Ditch change and limited any Coy Ditch change to 8 c.f.s.; it also characterized the unused portion as “abandoned.”
- The applicants appealed; the Colorado Supreme Court affirmed.

## Issues

1. Whether successors to users of Jackson/Dry Creek Ditch water could treat the supply as a transferable appropriative right and obtain a change in point of diversion, or whether prior adjudications and the contractual nature of the interest barred the claim under res judicata.
2. Whether a decreed Coy Ditch right of 16 c.f.s. could be transferred and changed in diversion point beyond the quantity historically applied to beneficial use.
3. Whether a change in point of diversion may be decreed if it enlarges historical use or injuriously affects other appropriators, including junior priorities.
4. Whether labeling the unused portion of a decreed amount as “abandoned” is legally operative where that portion never ripened into a water right through beneficial use.

## Decision

- The court affirmed the judgment.
- Jackson Ditch phase: the claim to change diversion was denied because the applicants’ interest was contractual and the controlling issues had been previously adjudicated; res judicata barred relitigation.
- Coy Ditch phase: the transferable/changeable right was limited to 8 c.f.s., the maximum quantity shown to have been historically applied to beneficial use.
- The trial court’s “abandonment” finding as to the excess over 8 c.f.s. was treated as harmless surplusage because a right that never came into being cannot be abandoned.
- The court upheld the limitation of any approved change to historical beneficial use to prevent injury to other appropriators.

## Legal Principles

- A person receiving water under a ditch arrangement “without charge” may hold only contract-based consumption rights, not an independent appropriative water right; successors take the same contractual interest.
- Res judicata applies in water proceedings: if prior litigation between the parties or their privies adjudicated the nature and scope of the claimed interest, a later change-of-diversion proceeding cannot relitigate it.
- A water decree protects only the quantity that has actually been applied to beneficial use; the enforceable right is bounded by historical beneficial use rather than the paper decree alone.
- Water not historically applied to beneficial use does not ripen into a water right; therefore, the unused portion cannot be abandoned because it never existed as a vested right.
- A change in point of diversion must not enlarge historical use or injure other appropriators’ vested rights, even if those other rights are junior in priority.

## Conclusion

The court rejected an attempted change of diversion for Jackson Ditch water because the claim was contractual and barred by res judicata, and it limited the Coy Ditch change to the 8 c.f.s. historically put to beneficial use, confirming that decreed amounts exceeding actual beneficial use do not create transferable rights and that changes must be confined to non-injurious historical use.


Green v. Chaffee Ditch Co., 371 P.2d 775 (Colo. 1962)