Montana v. Wyoming
Headline: Court finds Wyoming violated the Yellowstone River Compact, orders payment to Montana, and imposes rules protecting Montana’s pre-1950 water rights and Tongue River reservoir operations.
Holding: The Court awards Montana damages and costs for Wyoming’s Compact violations, orders payment into Montana’s Tongue River reservoir fund, and enters a decree defining when Montana may call for water and limiting Wyoming storage.
- Orders Wyoming to pay $20,340 plus interest and $67,270.87 in costs within 90 days.
- Requires payments be used for Tongue River Reservoir improvements in Montana.
- Limits Wyoming’s storage during Montana’s water calls and sets reservoir operation rules.
Summary
Background
The State of Montana sued neighboring states under the Yellowstone River Compact, claiming Wyoming reduced water flowing in the Tongue River at the Montana–Wyoming stateline in 2004 and 2006. The Special Master’s report was filed, and the Court entered a judgment finding that Wyoming reduced available water by specified acre‑feet and awarding Montana damages, interest, and costs to be paid into an account for Tongue River Reservoir improvements.
Reasoning
The Court addressed whether Wyoming’s actions violated Article V(A) of the Compact, which protects Montana users who had water rights before 1950. The Court awarded Montana money for the specific reductions and entered a detailed decree explaining how the Compact works. The decree explains when Montana may “place a call” (a request for water), how Wyoming must respond, how pre‑1950 rights are prioritized, limits on Wyoming storage during active calls, and rules for operating the Tongue River Reservoir and sharing water‑administration information.
Real world impact
Practically, Montana can make calls to protect older water users and Wyoming must limit storage or deliver water when required. The Court ordered Wyoming to pay specified damages, interest, and costs within 90 days and directed that the funds be used for reservoir improvements in Montana. The decree also leaves Indian tribal water rights undetermined and keeps the Court’s oversight open, so the Court can revisit enforcement or amend the decree if needed.
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