Story by: Michael Wright, Bozeman Daily Chronicle.

The federal government will pay $1 million to the Gardiner-Park County Water and Sewer District to settle a lawsuit the district filed over high levels of arsenic coming into its system from Yellowstone National Park.

The settlement agreement brings an end to the lawsuit the district filed in U.S. District Court in 2018 alleging that poor pipe maintenance resulted in high levels of arsenic getting into the district’s sewage ponds. Having arsenic in the ponds makes cleaning sludge out of the ponds more expensive and complicated.

After more than a year-and-a-half of legal wrangling and settlement talks, the two sides signed an agreement in February that the government would pay the district $1 million. Judge Susan P. Waters signed an order dismissing the case because of the settlement in mid-March.

A payment to the sewer district for the town at the park’s northern gate has already been made. Todd Shea, the attorney who represented the district, declined to comment.

Yellowstone National Park spokeswoman Linda Veress said in an email Friday morning that the money will pay for rehabilitating the district’s septic system “after years of naturally-occurring arsenic flowed out of Yellowstone National Park and caused deposits in Gardiner’s sewer lines and holding pond.”

“The park is pleased to have resolved this matter with the neighboring community of Gardiner,” Veress wrote.

Yellowstone has used the Gardiner-Park County Water and Sewer District’s sewage treatment plant for many years, according to court documents. The district uses sludge ponds to treat wastewater, and the ponds have to be emptied periodically.

High arsenic levels change where the sludge can be dumped, affecting the cost of removing it. The cost of emptying the ponds was estimated at more than $2 million in March 2015.

An engineer at the district told the district in 2015 that high levels of arsenic coming from the park were getting into the sewage treatment facility.

The lawsuit says the arsenic wasn’t coming directly from the park’s wastewater but likely from a different source, like leaky pipes or manholes inside the park. The district’s engineer recommended dealing with the arsenic infiltration problem before removing any of the sludge.

The district sent multiple letters to park officials in 2015 and 2016 seeking some resolution to the arsenic problem but received no written response until fall 2016, according to the lawsuit.

In separate discussions with the agency, however, park officials acknowledged the high levels of arsenic were coming from the park and said the National Park Service would help pay for sludge removal.

In a September 2016 letter, the park acknowledged the problems with its pipes but said it likely wouldn’t have money available to pay for the repairs until this year. The letter also acknowledged the agency was responsible for the sludge removal costs but didn’t say when that money would be available.

The park pledged to replace the sewer line in 2017, and a park spokeswoman said at the time that the money for the project was available.