BILLINGS – Attorneys from Montana and Wyoming are scheduled to square off before the U.S. Supreme Court on Monday in a cross-border dispute over the region’s scarce water supplies.
In a lawsuit dating to 2007, Montana accuses its southern neighbor of taking too much water from the Tongue and Powder rivers in violation of a 1950 agreement.
The issue before the court centers on a claim that Wyoming is using more water on crops due to advances in irrigation methods.
A court-appointed special master rejected that claim last year, but Montana Attorney General Steve Bullock challenged the ruling, setting the stage for Monday’s oral arguments.
Bullock does not say Wyoming farmers are diverting more water from the rivers. Rather, he says their use of more efficient irrigation methods has reduced runoff from agricultural fields — runoff that in the past flowed downstream into Montana for use by its farmers.
The special master, Stanford University law professor Barton Thompson, Jr., ruled last year that Wyoming could not be faulted for embracing irrigation improvements that encourage increased conservation.
The office of the U.S. Solicitor General has sided with Wyoming on the issue, although it has backed Montana in others aspects of the case.
Once the irrigation issue is resolved, the broader question of Wyoming’s overall water use still needs to be settled.
Attorneys for Wyoming contend some water uses by its residents and businesses was not covered by the 1950 agreement, known as the Yellowstone River Compact.
Justices in October ruled that Montana has raised a valid issue with its lawsuit and rejected Wyoming’s attempt to dismiss the case.
But Montana has yet to make its case in terms of quantifying how much water Wyoming is actually using. State officials say that won’t happen until further legal issues are resolved.
The lawsuit also could have consequences for Wyoming’s natural gas industry. Over the last decade, companies seeking a type of gas known as coal-bed methane have pumped billions of gallons of water from underground aquifers shared by the two states.
Montana contends the companies are draining water that would otherwise feed the Tongue and Powder rivers. A Texas-based energy company, Anadarko, attempted to intervene in the case but was denied in October.
Attorneys expect the case to grind on possibly for years before a final ruling.
North Dakota is also listed as a defendant because it is a party to the Yellowstone Compact. However, no claims have been made against it and the outcome of the lawsuit is likely to have little bearing on the state.
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