What happens to waterways with no water? Stream Team wants to know

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A University of Louisiana at Lafayette hydrologist is among a team of researchers that has secured $3 million in federal funds to examine what happens to waterways – and the creatures that reside within them – as they dry.

In a National Science Foundation-funded study, investigators plan to examine intermittent waterways, which dry or stop flowing periodically, as well as perennial streams that flow continuously, said Dr. Katie H. Costigan.

The assistant professor in UL Lafayette’s School of Geosciences will share $1.6 million with researchers from the University of California, Berkeley; Northern Arizona University; Virginia Tech; and the University of Arizona. The University of Oklahoma received $1.4 million from NSF for the same project.

“We are trying to understand why these streams dry and why streams often behave differently even though they may be very close to one another,” Costigan said.

“The goal is to answer what happens when rivers run dry. We are looking at how rivers dry as a function of space and time, and what happens to the life in these streams when this happens.”

The funds Costigan and the stream team will share are part of a $9 million round of funding NSF awarded earlier this month. The grants went to researchers nationwide who are examining how organisms respond to environmental changes.

Dr. Daniel C. Allen, an assistant professor of biology at the University of Oklahoma, is leading the streams initiative to which Costigan is contributing. In a press release, he said researchers want “to change the way we think about streams.”

“For decades, we have studied the ecology of streams that always have flowing water, while largely ignoring those that do not, but only 40 percent of U.S. streams always flow. This project will be one of the first to study both,” Allen said.

When streams dry, invertebrates and other creatures that dwell within them are affected, so researchers will study how drying influences ecology as well.

Fieldwork will take place at 100 sites in the central, southern and western United States. Costigan will conduct field research in Mississippi and Georgia, and will collect hydrological and ecological data at each site.

Some study sites are part of the NSF-funded National Ecological Observatory Network, which uses sensors to monitor water chemistry and nutrients, and populations of invertebrates, fish and algae.

Researchers will use data taken from the monitors and collected during their fieldwork to create hydrological models that can simulate different climate scenarios.

What researchers find could hold implications for water management and flood mitigation locally, Costigan said.

Although Louisiana’s residents often think of the implications of overflowing waterways, the other side of the coin – when rivers dry – is equally important.

“Worldwide, more than half of all streams dry, even in Louisiana,” Costigan said.  


Photo caption: The Arikaree River in eastern Colorado is an example of an intermittent waterway, one that dries or stops flowing periodically. (Photo courtesy of Dr. Katie Costigan)