A U.S. Geological Survey study shows that coalbed methane development has changed the chemistry of the surface water in parts of the Powder River. CBM wastewater was often discharged directly or indirectly into the stream.
The study analyzed three decades of data and determined that after extraction activities, the water contained more sodium and bicarbonate, which are compounds commonly found in CBM wastewater.
Report author Steve Sando says high sodium levels can be bad for irrigation, but he says the concentrations in the Powder River are not alarmingly high.
“With respect to use of the Powder River water for irrigation purposes, that is not going to be crossing some key threshold where we’ve got a problem,” Sando said.
He adds that the compounds in question are naturally occurring in groundwater, especially along coal seams; they just aren’t usually found in such high concentrations in surface water.