The Montana Department of Environmental Quality approved four new septic systems for a residential and commercial development along Highway 191 near the town of Big Sky. Septic systems can increase nutrient pollution that can deteriorate water quality issues and cause harmful algal blooms.
Guy Alsentzer, with Upper Missouri Waterkeeper, filed suit against DEQ. He says the agency failed to assess how nutrient pollution will harm the Gallatin River.
"The river is already over its tipping point, which is to say it's had neon green algal blooms several years. And those big, neon green, multi-mile-long algal blooms represent we don't have any carrying capacity in the river to handle more nutrient pollution."
The Gallatin is classified as an impaired river. Alsentzer says DEQ's approval of the septic systems is illegal and violates Montanans' constitutional right to a clean and healthy environment.
The lawsuit also challenges a state law allowing for developments to use septic systems if they are a certain distance from surface water.
DEQ was unable to comment due to the litigation.
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