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Montana v. Wyoming

ELR Citation: 48 ELR 20028
Nos. 137, (U.S., 02/20/2018)

The U.S. Supreme Court, in an unsigned judgment and decree, ordered Wyoming to pay Montana $20,340 in damages, plus $67,270.87 in costs, for reducing the amount of water available in the Tongue River in violation of the Yellowstone River Compact. The Compact protects pre-1950 appropriative rights to the beneficial uses of water of the Yellowstone River System. Montana filed suit against Wyoming in 2007, alleging it violated the Compact by allowing residents to use more efficient irrigation systems on their land. The irrigation systems resulted in less runoff flowing back into the river, which resulted in less water for Montana. A Special Master appointed by the Court determined that the amount of water available to Montana was reduced by 1,300 acre feet in 2004 and 56 acre feet in 2006, and recommended damages and costs be paid. The Supreme Court then entered judgment based on the Special Master's recommendations.