Planned revisions to water quality standards adopted to address phosphorus pollution within the Illinois River watershed received mixed reviews.

Some who participated in the virtual stakeholders meeting Tuesday night said the presentation of the draft criterion language revealed Tuesday was clear. They also appreciated the opportunity to offer written questions, which were relayed during intermittent breaks during the presentation and answered. 

Proposed revisions to the phosphorus standard would apply only to the Illinois River, Flint Creek and the Barren Fork Creek. The revised criterion would preserve a key part of the 0.037 mg/L standard adopted in 2003 for Oklahoma's scenic rivers, but make adjustments to other components, which caused concerns for some. 

The existing phosphorus standard for scenic rivers was validated in 2012 by a review committee and again in 2016 upon the completion of a stressor-response study. That study was undertaken in 2014 as part of an agreement between the states of Arkansas and Oklahoma in an effort to avoid litigation arising from water quality concerns.

The six-member panel's recommendations to the governors of Arkansas and Oklahoma affirmed, with slight variations, the validity of the numeric standard adopted in 2003 for Oklahoma scenic rivers. The recommendation provided for a "six-month average total phosphorus level not to exceed 0.035 mg/L based on water samples taken" when surface runoff is not a dominant factor of river flow rates or algal growth production. 

Becky Veiga Nascimento, environmental specialist at the Oklahoma Water Resources Board, said she and others at OWRB have been working since then with several partners to address the panel's recommendations. Most of that work, she said, has focused on factors that affect monitoring because the magnitude value of 0.037 mg/L will remain unchanged.

The draft language, which will be presented formally in December during the agency's rulemaking process, would limit exceedences of the "six-month rolling average of 0.037 mg/L" for total phosphorus to no "more than once in a one-year period and not more than three times in a five-year period."

Nascimento said the proposed revisions, described as an "outgrowth" of the joint study recommendations, introduces a new term to Oklahoma's water quality standards. She said a "lot of understanding and work has been going in" the term "critical conditions." 

The term, Nascimento said, was introduced by the joint study committee in its final report. The committee defined the term as "conditions where surface runoff is not the dominant influence of total flow and stream ecosystem processes." 

The operational effect of including the term in the revised phosphorus standards being proposed for the Illinois River watershed would "limit the total phosphorus data that can be used for water quality assessment." Nascimento said samples from high-flow events would no longer be used to assess compliance with water quality standards. 

Nascimento said the proposed revisions were designed to help achieve the long-term solution of "attaining the water quality criterion." The one-year and five-year benchmarks set as part frequency criterion are intended to "make sure we sustain the protections once we are back to attaining the beneficial uses."

Mark Derichswieler, legislative co-chair of the Sierra Club's Oklahoma Chapter, said the move "away from monitoring high-flow runoff periods" would be a step backward. He said a "conscious decision" was made a few years before the existing phosphorus standard for scenic rivers was adopted in an effort to assess the extent of nonpoint sources from agricultural practices and urban development. 

"For the  lake downstream the problem is mass loading -- the pounds per year that settle in -- and we know that is influenced by these high-flow events," Derichswieler said. "We may be protecting the river, but the lake is another problem."

Derichswieler said ignoring high-flow events "will put the entire burden" of reducing the phosphorus load within the watershed on point-source polluters. Point-source discharges within the watershed, he said, can be traced primarily to municipal wastewater treatment facilities. 

Ed Fite, vice president of scenic rivers for the Grand River Dam Authority, said the Oklahoma Scenic Rivers Commission changed its water monitoring contract specifically to sample high-flow events when that decision was made. 

Fite said more than a year's worth of phosphorus can move through the Illinois River Basin during a single high-flow event than what might flow at base flow for a full year. He said the runoff from high-flow events carries into the river "legacy phosphorus" that remains in the soil due to past agricultural practices. 

Fite encouraged others to participate in two upcoming stakeholder webinars scheduled at 7 p.m. Sept. 22 and Oct. 6. A link to the webinars will be posted along with other information about the proposed revisions at the OWRB's website,


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