Viewpoint: Protecting Montana’s water quality needs sound science

Montana’s Department of Environmental Quality (DEQ) is now accepting public comment — through Feb. 8 — on a proposed new rule to limit the impact of nutrient pollution on Montana’s waterways. . The regulations are the result of Senate Bill 358, which was passed by the legislature in 2021.

SB 358 sought to repeal Montana’s existing “numerical” nutrient standards, which set quantifiable limits on the amount of nutrient pollution that can be discharged into waterways, and directed DEQ to revert to using so-called “narrative” standards, which say rather vaguely that discharges should not create problems in our waterways.

SB 358’s proposed changes have met with resistance from clean water advocates because in the past, these vague, narrative standards often failed to protect Montana’s high-quality waters from nutrient pollution, leading to blooms. harmful and toxic algae, low oxygen levels and negative impacts on our fisheries.

Narrative norms have also resulted in ineffective and incremental efforts to clean up degraded waterways. Wastewater engineers working for regulated dumpers designed and built a system that reduced nutrients somewhat, but proved insufficient to correct the problem. Engineers should therefore redesign and rebuild. Does that sound expensive to you? You bet it was.

To fix this, engineers told water scientists that a digital target was needed so they could design for it. Montana water scientists, myself included, have spent decades studying nutrient levels, algae levels, and other measures of water quality in healthy bodies of water. and nutrient contaminated water bodies throughout Montana. Using this data and laboratory studies relating these measurements to each other, scientists have developed numerical nutritional standards.

These standards were reviewed and approved by other scientists, accepted by the EPA, and eventually Montana’s approach was considered a model and adopted by other states struggling with nutrient pollution. Recently, the Montana legislature proposed to reverse course. While the details of a new narrative rule have yet to be fleshed out, one thing is certain: Without numerical goals, Montana will go back to letting our high-quality waters degrade until problems are evident, and engineers will go back to guessing what might work and trying again and again.

A better way would be to continue to use the scientific information we already have to develop nutrient loading targets for water bodies. This approach could divide water bodies into 3 groups: 1) water bodies where nutrient targets are met and should be maintained; 2) water bodies where objectives are not met and resulting water quality problems require a management plan to reduce loadings; and 3) water bodies where nutrient targets are not being met, but do not have nutrient-related water quality issues and can simply continue to monitor for issues.

In some bodies of water, other factors limit the growth of algae, which explains the third group. For water bodies in the second group, additional site-specific data is needed to inform management plans so that they are as effective as possible.

Such an approach would use existing and relevant scientific information to prioritize the water bodies most susceptible to nutrient-related issues and most likely to respond to nutrient management. It would also give engineers and land managers a meaningful target when designing systems to fix an existing problem or prevent degradation during a new development – ​​as required by the Clean Water Act.

Other technical issues are debated, but the big picture is this: Montana should not abandon decades of science-based nutrient targets developed to protect high-quality waters and restore degraded waters. You can express your views in writing or orally – this DEQ website explains how.

About Nereida Nystrom

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