Department of Civil, Construction, and Environmental Engineering

7-19-07

Contacts:
Dana Schmidt, CCEE communications specialist, (515) 294-8312, schmidtdiastate.edu
Chris Rehmann, CCEE assistant professor, (515) 294-1203, rehmanniastate.edu
Danielle Wain, CCEE graduate student, (515) 294-6346, wainiastate.edu

CCEE Researchers Earn NSF Grant to Study Iowa Lakes

Ames, Iowa – Iowa State University researchers are spending their summers on Iowa’s lakes. But these researchers aren’t cruising around on high-speed jet skis or soaking up the sun’s rays. Chris Rehmann, assistant professor of environmental engineering, and Danielle Wain, PhD student in environmental engineering, as well as three undergraduate research assistants are studying the lakes’ internal movements to better understand how nutrients and pollutants are transported from the lake’s boundaries to its interior.

With the help of a new, highly competitive $482,115 National Science Foundation (NSF) grant, Rehmann and his research team are conducting tests on Ada Hayden lake in Ames, Iowa, this summer, and will study West Okoboji Lake in Dickinson County, Iowa, next summer. While they’re conducting research, Wain says the researchers will run a Web site that provides real-time information to local community members about lake conditions—wind, water temperature, and so on, and educate the community about the research being conducted.

“Although much recent work has focused on boundary mixing processes, less has studied the ultimate fate of the mixed fluid,” says Rehmann. “We’re trying to answer the question: How do fluid mixed boundaries move into the interior?”

In lakes and other bodies of water, waves not only occur on the surface, but also under the surface. Those waves break along the sides of the lake, causing turbulence in the water and mixing of sediments and other nutrients or pollutants present as well as the transport of heat. This process is called boundary mixing. When the waves break on the shoreline or side of the lake, the materials they transport are dispersed back into the lake in intrusions.

Tracking these intrusions, as well as measuring the water temperature, wind speed, lake depth, velocity of particles in the water, and solar radiation, helps researchers understand what happens to the mixed materials when they’re dispersed into the lake.

Rehmann and Wain’s research is only a small piece of the puzzle for oceanographers and environmental engineers. If researchers can determine where the intrusions go in the interior of lakes, they’ll be able to determine where contaminants will end up if the water is polluted, as well as apply this research to oceans and other bodies of water.

“This is the first time researches have put together the pieces,” says Wain. “Other researchers have done studies in other contexts, and we’re trying to connect the dots other researchers haven’t been able to connect yet.”

Additionally, understanding how fluid boundaries move into the interior of a body of water, and thus how the heat is balanced, can help researchers by improving the climate modeling techniques used to study global warming.

Closer to home, Iowa middle school and high school students will benefit from the knowledge gained in this study. Rehmann and his research team plan to provide outreach activities for young students to teach them about water quality issues. The researchers also will hold a class at the Iowa Lakeside Laboratory, an organization run cooperatively by Iowa State University, the University of Iowa, the University of Northern Iowa, and the Board of Regents, State of Iowa.

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