The Montana Department of Environmental Quality is delaying implementation of revised water quality standards following a letter from federal regulators warning that some of the changes violate the U.S. Clean Water Act, state officials said this week.

In the mean time, Montana’s existing numeric standards for nitrogen and phosphorous pollution in the state’s wadeable streams and rivers will remain in effect, another twist in what’s been a lengthy and contentious effort to lift the so-called numeric nutrient criteria in favor of more flexible narrative standards as per GOP-backed legislation passed last year.

Last week’s letter from the Environmental Protection Agency asserted that despite the state’s claims otherwise, the legislation, Senate Bill 358, constituted a revision of water quality standards that’s subject to federal review. Indeed, EPA found the bill removed the numeric criteria outside of the normal process “without adequate information to demonstrate that the narrative criteria alone protect designated uses.”

The state will still forge ahead with rulemaking under the provisions of that bill, but it must do so in a way that passes muster with the EPA, which has authority to disapprove revisions to state and tribal water quality standards, DEQ said this week.

Exactly how DEQ will walk that tightrope remains to be seen: on one hand, the agency is required under SB358 to remove the numeric criteria and develop a process to implement narrative standards; on the other, EPA has now said on the record that provisions of the bill itself are inconsistent with the Clean Water Act.

“I don’t see how we’re going to get away from the explicit items that were found to be inadequate to protect Montana’s designated uses,” said Guy Alsentzer, director of Upper Missouri Waterkeeper and an opponent of SB358, at a meeting Tuesday of the Nutrient Work Group, a stakeholder panel formed to guide implementation of the bill. “What’s going to fundamentally change that’s going to resolve these issues?”

Nutrient pollution impairs 35% of river miles in the state, something that in high enough quantities can cause harmful algal blooms, fish kills and more. The criteria in question here only affect wadeable, small and medium-sized streams and rivers, as well as portions of the Yellowstone and other larger bodies.

Alsentzer and other environmental advocates have argued that narrative standards, which rely on descriptive evaluations of water health, are too subjective and too reactive to protect water quality compared to more precise concentration measurements taken at the source. His group in March sued the EPA to force it to acknowledge SB358 as a water quality revision and evaluate it for compliance with the CWA. The lawsuit is ongoing, though Alsentzer said last week that EPA’s action “appears to be a response to our lawsuit.”

Water quality standards, per the Clean Water Act, define in state or federal law certain designated uses for a water body, either numeric or narrative criteria to protect those designated uses and provisions to stop water quality degradation.

They govern discharge permits to point-source polluters like sewage treatment plants, municipal governments and others. Montana in 2014 was one of the first states to heed years of urging from the EPA and adopt numeric criteria to protect and restore river health from nutrient loading.

However, regulated entities in Montana argued numeric standards were too costly to meet with current technology, leading first to a variance program and eventually to SB358.

DEQ has already developed a draft rule package laying out the broad strokes of how narrative criteria under the legislation will translate to permit limits for dischargers in various watersheds. Now, however, completion of that rulemaking will be postponed, and in June, DEQ and the stakeholder group will begin laying out a new variance scheme that will allow permittees to gradually meet the numeric standards. New permits or permit renewals are otherwise to be issued in accordance with the state’s EPA-approved numeric criteria, the EPA said.

DEQ still plans to finish developing rules to remove the numeric criteria and implement the standards in SB358, but will now do so on an indeterminate timeline.

“EPA’s letter acknowledged DEQ’s ability to move forward with different water quality standards as long as we demonstrate that those standards are protective of beneficial usages,” DEQ Water Quality Division administrator Amy Steinmetz said Tuesday. “Because state law directs us…we will continue to move forward with that process.”

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