## Facts

- Farmers in Cassia County, Idaho pumped irrigation water from a shared limestone aquifer primarily recharged by precipitation.
- By the late 1950s and early 1960s, development of roughly twenty wells led to summer withdrawals that exceeded the aquifer’s average annual recharge, causing declining water levels.
- Senior groundwater appropriators (including Baker) alleged that junior pumping impaired their wells’ production and sought an injunction to stop junior pumping until senior wells returned to normal production.
- After a bench trial centered on competing hydrology experts, the district court found that total pumping exceeded average annual recharge and that continued pumping constituted “mining” the aquifer.
- The district court established a priority order among wells, enjoined certain junior wells to prevent withdrawals exceeding recharge and interfering with seniors, and assigned ongoing administration (including future recharge determinations and adjustments) to the Idaho Department of Water Administration.

## Issues

1. Whether Idaho’s Ground Water Act allows groundwater withdrawals in excess of the aquifer’s average future recharge when such withdrawals deplete the aquifer and impair senior rights.
2. Whether groundwater in a common aquifer is governed by prior appropriation (priority) or by correlative rights (proportional sharing among users).
3. Whether the trial court properly granted injunctive relief curtailing junior pumping and assigned continuing administration of the decree to the state water agency.

## Decision

- The Idaho Supreme Court affirmed the judgment.
- The court held the Ground Water Act does not permit “mining” an aquifer by pumping beyond the average rate of future recharge when that practice depletes the supply and impairs senior appropriators.
- The court rejected a correlative-rights allocation and applied prior appropriation to groundwater, permitting curtailment of juniors before seniors in a shortage.
- The court upheld the injunction limiting junior pumping and approved reliance on the state water agency for continuing, technical administration of recharge and pumping limits.

## Legal Principles

- Under Idaho’s Ground Water Act, groundwater development must be consistent with maintaining reasonable pumping levels; withdrawals exceeding the average rate of future recharge that deplete the aquifer and harm senior rights are unlawful.
- Idaho applies the doctrine of prior appropriation to groundwater; in times of insufficient supply, junior appropriators may be enjoined or curtailed to protect senior rights from material interference.
- Courts may impose injunctive pumping restrictions in an overdrawn aquifer and may assign ongoing implementation and adjustment of technical hydrologic determinations to the responsible state water agency.

## Conclusion

The court sustained a priority-based curtailment regime for an overdrawn aquifer, holding that the Ground Water Act bars recharge-exceeding withdrawals that deplete groundwater and injure senior users, and approving administrative oversight to manage changing hydrologic conditions.


Baker v. Ore-Ida Foods, Inc., 513 P.2d 627 (Idaho 1973)