Updated 11:45 a.m. Monday, March 7

By Amanda Eggert EBS Staff Writer

BIG SKY – The discharge of treated wastewater from a Yellowstone Club holding pond that began March 3 stopped at 4:30 a.m. this morning, according to an email sent to EBS from Stephanie Lynn, education and communications coordinator with the Gallatin River Task Force.

Last Thursday, a 24-inch pipe exiting the pond burst, sending as many as 30 million gallons of treated wastewater into a tributary of the Gallatin River. A diversion rerouted 5 million gallons of wastewater to a lower golf course pond until it reached capacity.

According to a webpage dedicated to the incident on the Big Sky Water and Sewer District website, YC crews brought in heating equipment on Sunday to melt the ice around the standpipe so they could better assess the damage. The team of engineers was scheduled to meet Monday morning to begin working on a repair.

Montana Department of Environmental Quality officials have been collecting water samples of affected waterways through the weekend and sending them to a lab for analysis.

Most results from the samples are not yet available from the lab, although some turbidity readings were made public by the DEQ. Turbidity refers to the suspended particles in a liquid and is considered an important marker of water quality.

In a press release obtained by EBS this morning, Kristi Ponozzo, Montana DEQ’s public policy director said, “The turbidity is lowering in the creeks closest to the source while the turbidity in the surface water further away is increasing slightly. According to the sampling team this is normal as the turbidity in the streams closest to the point of discharge slowly clear and sediment moves down stream. The turbidity readings are still well above the standard of an increase of 5 NTU.”

The highest turbidity reading the DEQ has taken so far was a reading of 1688 NTU, or nephelometric turbidity units, from Second Yellow Mule Creek, which was the first waterway impacted by the wastewater. That reading of 1688 NTU was taken Saturday. Sunday it dropped to 740 NTU at the same site.

Grant Burroughs, the Big Sky Water and Sewer District’s wastewater treatment specialist, said so far the transport of YC’s wastewater to the BSWSD sewer main is proceeding without incident. The transport is being accomplished with licensed septic haulers. Burroughs said the plant has plenty of capacity at this point to handle the additional wastewater.

A special section of EBS with in-depth coverage of the spill and its impacts will be distributed in Big Sky on Wednesday, March 9.