Nov 11, 2020

ISU Researchers Study how Intermittent Streams Affect Water Quality

An Idaho State University research team has received a $1.3 million grant to study how streams affect downstream water quality. 

idaho water quality

An Idaho State University research team received a $1.3 million grant to study how streams that typically go dry for much of the year affect downstream water quality. 

The four-year project involves eight universities sharing $6 million in National Science Foundation funding, according to the Idaho State Journal. 

Researchers say their work could also help water users better understand their supply outlook. 

The researchers will focus on three streams in three different regions: the western mountains, the central plains and the southeastern forests. The mountain streams include Gibson Jack. 

In 2015, the Obama Administration's EPA approved revisions to the Waters of the U.S. Clean Water Rule, which requires permits for discharges, dredging or dirt fill of regulated waters. The 2015 Rule specified that any waterway with a bed, a bank and a high-water mark, would be subject to regulation. A repeal of the rule by President Donald Trump took effect on Dec. 23, 2019, revising the definition of "Waters of the U.S." to cover only streams that flow and are connected to navigable waters in a typical year.

The ISU team's co-lead investigators are Sarah Godsey, an associate professor of geosciences, and Rebecca Hale, an assistant professor of biological sciences specializing in water quality. The team also includes; Professor Kathleen Lohse, who is an ecosystem scientist; Ken Aho, an associate professor of community ecology and statistics; and Yaqi You, a visiting assistant professor who recently left for New York but will remain involved in the project. 

Godsey and Hale conducted a pilot project in summer 2019, evaluating the impact of intermittent tributaries on the water quality in Gibson Jack Creek in Pocatello.

"Our pilot data suggests that intermittent headwater streams, even though they're tiny and not flowing all the time, may have an outside impact on downstream, perennial water quality," said Godsey. "That's surprising."

According to Godsey, intermittent streams may support different populations of microbes that break down leaves and other material in streams. The intermittent streams may also cause leaves, debris, manure and other materials that build up over time to flush all at once. This would temporarily elevate nutrient concentrations downstream.

Although there is a national database of intermittent streams, about half of them are incorrectly classified, according to Godsey.

"I definitely hope we're going to help improve the models that say when and where the streams are drying," Godsey said.

The data will be pooled with research by investigators from: University of Kansas, Haskell Indian Nations University, Kansas State University, University of Alabama, University of Mississippi, University of Oklahoma, Alabama A&M and University of Southern Mississippi. 

Students with the Shoshone-Bannock Youth Program in Fort Hall will be invited to help with water sampling and to learn about the water quality research.

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