DEQ Proposal Disregards Best Available Science
This week, conservation groups Upper Missouri Waterkeeper and the Montana Environmental Information Center submitted a comment letter to the Montana Department of Environmental Quality (DEQ) highlighting major deficiencies in the proposed assessment methodology for pH and the department’s disregard for scientific and legal requirements.
“It’s no secret that Montana’s waterways and fisheries are already under extreme stress; yet instead of ensuring our monitoring can identify – and prevent – harmful conditions, DEQ is proposing weak assessment methods that fail to detect when harm is occurring,” said Guy Alsentzer, Executive Director of Upper Missouri Waterkeeper. “Despite being the agency charged with protecting water quality, DEQ’s proposal does the opposite – undermining Montanans’ constitutional rights and pushing our rivers further toward their tipping point.”
Water quality assessment methods determine how the state evaluates whether waters are meeting water quality standards and supporting aquatic life. Developing strong assessment methods is critical to maintaining high quality waters and efficiently identifying degraded water quality. The pH assessment methodology currently being updated by DEQ includes several scientific and legal flaws that will not afford Montana surface waters the necessary management capable of maintaining and preserving high-quality water or accurately and efficiently identifying degraded water quality.
Key Scientific Issues in DEQ’s Proposed pH Assessment Methodology:
- Inadequate sampling – limited grab samples and off-season monitoring cannot detect pH variability or impairment, which is almost always associated with algal blooms during the growing season.
- Does not account for precipitation events or mining impacts – Montana’s history of mining means pH can vary widely based on past mining activity, but the methodology applies a single one-size-fits-all approach statewide.
- Relies on methods that contradict DEQ’s own scientific findings about what constitutes representative water quality sampling.
- Would reduce DEQ’s ability to identify impaired waters, allowing degradation to go unaddressed and harm to continue.
Suggested Improvements:
- Require continuous pH monitoring, including measurements before dawn and in the late afternoon when harmful extremes typically occur.
- Conduct multi-day monitoring during peak algal growth periods, with frequent measurements to capture true variability.
- Require continuous monitoring before removing waters from the impaired list to ensure improvements are real and lasting.
- Increase sampling during and after storm events, especially in waters affected by historic mining, to capture pH crashes.
In addition to the scientific flaws identified, the comment letter likewise highlights legal issues with the proposed assessment methodology. DEQ’s revisions would implement standards of general applicability without formal rulemaking, in violation of the Montana Administrative Procedures Act and the Montana Water Quality Act. Because the proposed assessment methods directly affect how water quality standards are applied, including whether assessed waters are listed as impaired, the changes legally qualify as new or revised water quality standards, which must go through public rulemaking and federal review under the Clean Water Act.
Furthermore, Montana’s Constitution requires the State to “maintain and improve a clean and healthful environment” and assure its actions afford “protections which are both anticipatory and preventative,” but DEQ’s proposal will fail to detect harmful pH levels, and as a result, are incapable of adequately identifying or preventing harm to the environment.
The groups request DEQ withdraw its proposals and reconsider the assessment methodology, addressing the scientific, public policy, and legal issues noted by the groups.
DEQ also requested public comment on Montana’s 2022-2024 Draft Water Quality Integrated Report and called for data and surface water assessment requests for the next integrated report. Waterkeeper submitted comments and re-submitted the Petition for a Nutrient Impairment Designation on the Big Hole River along with all nutrient and water quality data, photo/video evidence of algal blooms, and a macroinvertebrate study to DEQ supporting the request.
Waterkeeper originally petitioned the department to declare the Big Hole River as impaired last April, but the petition was denied after DEQ refused to assess the numeric nutrient data demonstrating sections of the river are nutrient impaired and failing to support designated uses. Waterkeeper is again formally requesting the Department fulfill its duty to identify the Big Hole River (and other qualifying waterbody segments) as impaired due to widespread algal blooms fueled by excessive pollutants, including nitrogen, phosphorus, temperature, dissolved oxygen and sediment, as required under the Clean Water Act.