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Sustainable Idaho: Intermittent Streams

Intermittent Stream Pic.jpg
Xander Lacy

I officially finished our Drought series last week after talking about the impacts of fire on forests and human health. Even so, the effects of drought are seemingly inescapable in Southern Idaho. For this episode, I invited graduate student, Justin Miller, to come to talk about his research on intermittent streams and as you’ve guessed, they are impacted by drought.

First I asked for the big overview. What is the focus of the research? Miller explained that he focuses on intermittent streams as opposed to perennial ones. Intermittent streams are streams that don’t continually flow throughout the year. Perennial streams do. But if streams are not flowing year-round, are they important? Well according to the Environmental Protection Agency, or EPA, almost 60% of all streams in the U.S. excluding Alaska, don’t flow year-round. A 2008 EPA report found that intermittent streams “provide the same ecological and hydrological functions as perennial streams by moving water, nutrients, and sediment throughout the watershed.” So it turns out that understanding these streams is incredibly important to understanding whole watersheds and water quality.

That said, Miller’s focus is actually on how intermittent streams affect carbon cycles. Studying the global carbon cycle is just studying how carbon atoms move throughout the Earth and its atmosphere. After Miller explained what exactly the global carbon cycle is, I had to ask what his research has shown. How do intermittent streams affect this cycle?

Well as it turns out, whether or not an intermittent stream is a carbon sink or source really depends on a number of factors, like time of year for example. In areas surrounding Pocatello, there are plenty of opportunities for intermittent stream research. Miller’s research takes place at Gibson Jack Creek and he’s been studying this particular area since May.

He then spoke about the drought and what he’s learned about it through his research. Because of the drought, streams that dry seasonally are only increasing in number. This adds more reason to why intermittent stream research is important. Miller also made the point that this research is important because intermittent and perennial streams don’t see the same governmental protections.

Miller elaborated on the differences in protections between stream types. To recap what Miller said, ephemeral streams, or rain-dependent streams, and intermittent streams, or seasonal streams, haven’t seen the same treatment as year-round, perennial streams in the past. As of right now, ephemeral streams are excluded from the Navigable Waters Protection Rule, NWPR, published in 2020, which means they are not protected under the Clean Water Act. Whether this is good or bad is up for debate.

So overall, we’ve learned the differences between intermittent, ephemeral, and perennial streams, the importance of intermittent streams when studying waterways and carbon cycles, and again, how drought is making an impact on Idaho’s landscape. Miller concluded by reiterating the importance of recognizing and protecting seasonal and rain flow streams.

To learn more about the official definition of Waters of the United States and what the Navigable Waters Protection Rule changed, visit our page on to see links for additional information. Thanks for listening and again, for those interested in ISU’s Sustainability Club, please email

Sources:2008 EPA Report

Waters of the United States Definition

Opinion: NWPR Changes Leave U.S. Waters Vulnerable

Ailie Maclean was born and raised in Alaska but moved to Kimberly, Idaho right before high school. Ailie is an undergraduate Political Science and Global Studies major at ISU. She is going into her last year at ISU as Vice President of Idaho State’s student government, ASISU, and has served as an Honors Program Mentor, Communications Envoy, and ASISU Supreme Court Justice in past years. In her free time she enjoys reading, longboarding, hiking, watching anime, and swimming in unique places (Silfra in Iceland for example). Ailie plans on studying environmental, or some variation of international law, after taking a gap year to travel and work abroad.