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Feds reject plan to pump Moneta oilfield waste into potential drinking water

At Moneta Divide field in Fremont County, EPA says plan by driller Aethon doesn’t meet standards to exempt Madison underground aquifer from protection.

On the Wind River Indian Reservation, Fort Washakie is home to nearly 1,800 people. (Matthew Copeland/WyoFile)

by Angus M. Thuermer Jr., WyoFile

Federal environmental officials have rejected a request by Aethon Energy to pump Moneta Divide oilfield wastewater into the Madison aquifer, saying the deep reservoir could be used for drinking water, especially by tribal nations on the Wind River Indian Reservation.

The Wyoming Oil and Gas Conservation Commission in November 2020 approved wastewater disposal into the 15,000-foot deep well, but the U.S. Environmental Protection Agency said last week the state’s decision did not align with federal rules.

Aethon’s plan does not support a finding “that the aquifer cannot now and will not in the future serve as a source of drinking water,” the EPA wrote in a 20-page record of decision. Aethon argued, and the Wyoming commission agreed 4-1, that the underground Madison formation was too deep and remote to be used for drinking water.

The EPA relied on the Safe Drinking Water Act as the authority under which to protect the aquifer. It also cited climate, environmental justice and tribal interests in its decision, pointing to the nearby Wind River Indian Reservation as a community that could use the water.

“We have to make sure our future generations have a reliable source of clean water.”


“The significance of that is the EPA finally didn’t wimp out on us,” said Wes Martel, a member of the Wind River Water Resources Control Board. “We’re just glad they now have some people in place following up on their Indian policy.”

The Eastern Shoshone and Northern Arapaho Tribes “foresee increased reliance on groundwater for drinking water purposes and anticipate needing to access deeper aquifers, such as the Madison aquifer, as the climate changes and water resources grow scarcer,” the EPA wrote in a 94-page analysis of tribal interests. The agency cited historic cultural and spiritual ties to the land and water and tribes’ status as sovereign nations in its decision.

“We have to make sure our future generations have a reliable source of clean water,” Martel said. “Our reservation, this is all we have left. We’ve got to do our best to protect it.”

The Powder River Basin Resource Council, along with the Wyoming Outdoor Council and others, has spent years monitoring discharge reports and industry permits and was vital in challenging pollution threats, Martel said.

The EPA understood that science, and the law did not support Aethon’s request, said Shannon Anderson, organizing director and staff attorney with the resource council. “They recognized the value of our groundwater resources and the need to protect those into the future,” she said, hailing the decision.

Vast quantities of water

Aethon must find a way to dispose of produced water — a brine pumped from energy wells to release gas and oil — as it expands the Moneta Divide field by 4,500 wells. The U.S. Bureau of Land Management authorized that expansion in 2020, leaving the question of water disposal to Wyoming, which has authority over surface and underground water quality under overarching federal standards.

Aethon must find a way to dispose of the equivalent of 120 Olympic-sized swimming pools full of produced water a day to expand the field. Aethon and Burlington Resources, a co-producer at Moneta, could generate $182 million a year in federal royalties, $87.5 million a year in Wyoming severance taxes and $106 million annually in County Ad Valorem taxes from the expansion.

An elk skull adorns a fencepost near the Eastern Shoshone’s buffalo management land on the Wind River Indian Reservation. (Katie Klingsporn/WyoFile)

But Aethon has violated state permits that allow it to pump some produced water into Alkali and Badwater creeks that flow into Boysen Reservoir, a drinking water source for the town of Thermopolis. Wyoming’s Department of Environmental Quality has notified the Dallas-based investment company of its infraction and has required Aethon to reduce the salinity of surface discharges this year.

The DEQ this year listed the two creeks as “impaired” and unable to sustain aquatic life. Underground injection of wastewater into the Madison was to be a new component of the disposal program.

The EPA cited climate change, drought, increasing temperatures and use of reservation surface water by others as some of the reasons to preserve the Madison aquifer.

“Removing the existing statutory and regulatory protections for a potential source of high-quality drinking water for the rural and overburdened communities in Fremont County and on the WRIR would further exacerbate existing inequities particularly with respect to historic and ongoing adverse and cumulative impacts to water resources and community health,” the EPA wrote.

“Thus, equity and environmental justice considerations, which include Tribal interest considerations, support maintaining the existing [Safe Drinking Water Act] protections that apply to the aquifers consistent with Congressional intent to protect both current and potential future sources of drinking water,” EPA documents state.

Neither Aethon nor a representative of the Oil and Gas Conservation Commission responded immediately to a request for comment Wednesday. But WyoFile received this response from Tom Kropatsch, oil and gas supervisor for the Wyoming Oil and Gas Conservation Commission, shortly after publication:

“We do not agree with EPA’s decision on this application. We are still reviewing their decision and the information utilized by EPA in support of their decision. Much of this information was not part of the original application or a part of the record. EPA did not follow the standard procedure of allowing the WOGCC and the applicant to review and respond to the additional information they had available prior to making their final decision. EPA evaluated data that differs in its geographic, geologic, engineering, and other technical information. EPA also inappropriately related the proposed injection location to other areas of the state. Since the data EPA reviewed does not accurately reflect the conditions at the location of the proposed disposal well it is not appropriate to rely on it for a decision on this application. The WOGCC is reviewing EPA’s decision and weighing its options for further action.”

This article was originally published by WyoFile and is republished here with permission. WyoFile is an independent nonprofit news organization focused on Wyoming people, places and policy.