Kansas v. Colorado
Headline: Court finds Colorado’s post-Compact well pumping violated the Arkansas River Compact, upholds Special Master’s liability findings, and rejects reservoir and storage claims that lacked proof of material depletion to Kansas users.
Holding:
- Requires Colorado to account for post-Compact well pumping reducing water to Kansas
- Says reservoir operating departures must show actual material depletion to be a violation
- Remands case for remedy phase to calculate relief for Kansas water users
Summary
Background
This case is between the State of Kansas, the State of Colorado, and the United States about how water from the Arkansas River is shared under the Arkansas River Compact. Kansas said that after the Compact was adopted, increased groundwater well pumping in Colorado and operations of some federal reservoirs reduced the amount of usable river water reaching the Colorado-Kansas border. A Special Master held a liability trial and issued a detailed report finding that post-Compact well pumping had materially depleted usable flows but that Kansas had not proved claims about the Winter Water Storage Program and the Trinidad Reservoir.
Reasoning
The Court focused on whether any development in Colorado had materially depleted the river’s usable flow, as Article IV-D of the Compact bars significant reductions in usable water at the state line. The Justices agreed with the Special Master’s factual findings and accepted the Durbin method as modified by Larson to measure usable flow. The Court allowed 15,000 acre-feet as the pre-Compact pumping baseline, rejected Colorado’s delay (laches) defense, and concluded that benefits from the 1980 operating plan do not offset proven Compact violations. The Court dismissed claims that relied only on departures from operating principles because Kansas failed to show actual material depletion.
Real world impact
The Court’s ruling decides the liability question and sends the case back to the Special Master to determine remedies. Practically, the decision may lead to adjustments or compensation for Kansas water users, closer limits or accounting for Colorado well pumping, and continued oversight of reservoir storage under the Compact. The liability ruling is final, but specific relief and implementation will be determined in the remedy phase.
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