U.S. Supreme Court Opinion in Montana v. Wyoming, et al., No. 137 Original
On May 2, 2011 the United States Supreme Court issued an opinion in the interstate water suit, Montana v. Wyoming, et al., No. 137 Original. The case concerns alleged violations of the Yellowstone River Compact that was entered into among the States of Montana, Wyoming and North Dakota. Montana brought the suit alleging that, among other things, Wyoming was breaching the 61-year-old agreement by increasing its farm and ranch water use efficiency. Interestingly, Wyoming water users had not increased the amount of their diversions in violation of the Compact, but rather as those users became more efficient, the amount of return flow declined. Montana made the novel argument that the Compact apportioned the water between the States based upon the amount they were consuming in the 1950s, not the amount they were diverting. The Special Master appointed to the case dismissed that claim and the Supreme Court affirmed his ruling. Justice Scalia filed a solo dissent. The case will now go back to the Special Master for additional proceedings to address other alleged Compact violations.