State of Montana Officially Declares Gallatin River ‘Impaired’

Nutrient pollution levels too high to support aquatic life, recreation

Today, the Department of Environmental Quality (DEQ) formally declared the middle segment of the Gallatin River ‘impaired’ by algal blooms under Section 303(d) of the federal Clean Water Act (CWA).

“This decision is a clear victory for the Gallatin River, our blue-ribbon fishery, and all those that depend on it,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “DEQ must now provide a transparent and enforceable game plan to cleaning up the river, including developing a pollution diet and reducing nutrient pollution discharges that are a primary source contributing to noxious algal blooms for too long.”

In June 2022, DEQ made a preliminary finding that the Gallatin River merits a Category 5 impairment designation as the river’s designated uses (recreation, aquatic life) have not been attainable due to excessive levels of nitrogen and phosphorus. The determination comes in response to a petition submitted by Upper Missouri Waterkeeper and conservation partners in March 2022 that requested the department determine the middle segment of the Gallatin River ‘impaired’ by nutrient pollution. 

Miles-long neon-green algal blooms, triggered by human-made nutrient pollution from sprawl development and inadequate waste management, have degraded water quality and aquatic habitat in the Gallatin River every summer since 2018. This formal impairment designation under the CWA will prompt the formation of a Total Maximum Daily Load (TMDL), a science-based, proven and effective planning tool used to identify pollution sources, and prevent, reduce, or clean up excess pollution, all towards restoring the health of a waterway. 

Waterkeeper compiled an FAQ document on the impairment designation here.

This impairment designation means that, pending creation of a pollution diet for the Gallatin, the agency must stop authorizing new discharge of nutrient pollution, like it just did for the Quarry development last month. 

Waterkeeper is encouraged by this determination and will continue to advocate for a healthier future for the Gallatin River.