The Montana Department of Environmental Quality (DEQ) is seeking public comments on the Draft Eutrophication Assessment Method for Wadeable Streams and Medium Rivers.
“Eutrophication” is the fancy scientific word describing the over-saturation of a waterbody with nutrients, including nitrogen and phosphorus, resulting in unhealthy ecological conditions.
The Draft Eutrophication Assessment Method is being proposed by DEQ to determine whether a waterbody threatened by nutrient pollution is meeting Montana’s water quality standards and supporting aquatic life and recreation, or whether it’s not, and is therefore impaired. If a waterbody is determined to be “impaired,” it is added to Montana’s list of impaired waters in the biannual Water Quality Integrated Report, and a “pollution diet” or total maximum daily load (TMDL) is developed to limit the pollutant causing impairment and to restore waterway health.
This draft Method will serve as one of DEQ’s narrative nutrient regulatory tools following the Montana Legislature’s 2025 elimination of numeric nutrient water quality standards to protect our waterways. Core issues with the Method is that it, rather than addressing the most pervasive source of pollution degrading Montana’s waterways, requires nutrient pollution to actually harm our rivers and streams while simultaneously making it even more difficult to detect, measure, and identify pollution, including weakening the thresholds for action.
Here are five key issues with the draft Eutrophication Method:
- It reacts to pollution instead of preventing it – This method is purely reactionary and provides no mechanism for preventing degradation, despite the law requiring a precautionary approach.
- The pollution thresholds are too high – The proposed limits for nutrients, dissolved oxygen, algae, and macroinvertebrates are too high, or weak, to reliably protect rivers and sensitive species from nutrient pollution. The only streams and rivers that may be identified as impaired are those that show consistent signs of severe nutrient pollution.
- It does not require adequate monitoring – The Method allows inadequate sampling (such as assessing nitrogen and phosphorus with as few as 3 samples over 2 years, or not requiring sampling for nutrients at all), which will allow harm from nutrient pollution to go undetected for years.
- There is a high chance of failing to identify nutrient impairment – When impairment goes undetected, nutrient pollution will continue to contribute to ongoing and worsening degradation. Where impairment is detected, any response will be slow and inconsistent.
- It fails to protect downstream uses – The method fails to account for communities, businesses, and other downstream uses that depend on clean water and healthy rivers.
Montana DEQ is accepting public comments on the proposed rule revisions now through September 11. Use your voice to speak up for the importance of protective, science-based eutrophication assessment methods for our waterways – you can submit comments to DEQ here.