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UW water study helps resolve interstate legal battle

Water is precious. So much so that it can even lead to arguments between states.

Volume 14 | Number 2 | January 2013

By Ron Podell
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Water is precious. So much so that it can even lead to arguments between states.

That’s what happened when Montana became concerned that water produced along with coalbed methane in Wyoming could flow into rivers and be carried into Montana, potentially making it too salty and not optimal for irrigation.

After Montana passed regulations to address its concerns, the U.S. District Court for the District of Wyoming objected, ruling that the Cowboy State’s neighbors to the north had not shown that their regulations were based on appropriate scientific and technical data.

That’s when University of Wyoming geology professor Carol Frost and her students stepped in to help settle the issue. They collected 30 water samples on the Powder River, along its course from central Wyoming to Montana, to its confluence with the Yellowstone River, and measured carbon isotope levels during both the spring and fall.

Their findings, says Frost, supplied the critical scientific information that dispelled Montana’s notion.

“Water from the coalbed methane wells was different than the Powder River water. As you follow the river downstream, the carbon isotope values of the river go up because of the presence of coalbed methane-produced water,” says Frost, who also serves as UW’s vice president of special projects. “But, further downstream, other tributaries come in and carry fresh water. By the time the water enters Montana, the isotope levels are back down to a normal range.”

When water crosses state lines, Frost acknowledges that the downstream state (in this case, Montana) can hold the upstream state responsible. But, she says, the parameters Montana used to determine agricultural use aren’t distinct between produced water from coalbed methane and ordinary surface waters.

Under the Clean Water Act, the Environmental Protection Agency (EPA) approved Montana’s water regulations in 2003 and 2006, respectively. Montana intended the regulations to address the possible impacts of coalbed methane gas development in Wyoming on water quality.

Subsequently, four separate actions were filed and later consolidated, which sought review of the EPA’s approval of Montana’s water quality standards. In October 2009, the U.S. District Court for the District of Wyoming vacated the EPA’s approval of Montana’s 2003 and 2006 water quality standards. The court remanded the matter to the EPA with instructions to consider the 2003 administrative record and determine whether the 2003 numeric standards were based upon appropriate technical and scientific data.

“Our work showed that the parameters Montana was regulating weren’t the parameters that would allow them to identify the source of the problem,” Frost says. “When we identified a suitable parameter —carbon isotopes—we established that water quality degradation in Montana was not the result of coalbed methane production in Wyoming.”

Rather, saline levels in Montana’s portion of the Powder River were found to be caused by agricultural practices, such as how much fertilizer was applied to crops, Frost says.

The state of Montana took its case to court, but the court ruled that Montana’s regulations were not based on science. As a result, the case was thrown out, Frost says. Montana is sticking to its argument based on its water quality regulations, which are under EPA review. 

“Basically, we’ve produced a better chemical discriminant for identifying when coalbed methane water is in the surface water,” Frost says of the court actions.

The UW College of Law published an article about the subject in Wyoming Law Review in 2011.

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