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Credit Hour Discusses the Missouri River with Professor Mark Sweeney

Mark Sweeney The USD Podcast Credit Hour interviewed Mark Sweeney, associate professor of sustainability and environment.

Vermillion, S.D. – Mark Sweeney, associate professor of sustainability and environment, discusses the effect of accumulating sediment on the Missouri River during the latest episode of Credit Hour, the University of South Dakota’s official podcast.

Sweeney addresses how sediment issues can cause problems in downstream areas like the Lewis and Clark Lake near Yankton. Because the Gavin’s Point Dam blocks the natural flow of the river, sediment builds up behind the dam, which will, in time, cause the lake to fill in.

“If you fill in that reservoir with sediment, you’re going to eventually reduce the hydroelectric capacity of the dam and reduce boating and other recreational opportunities on the lake, which could potentially have devastating economic impact to the surrounding towns,” Sweeney said.

To better understand the problems with sediment, Sweeney studies the river’s tributaries to learn where the sediment is coming from. The largest tributary, the Niobrara River in Nebraska, contributes the most sediment into the reservoir. The Missouri River itself also carries a significant amount of sediment with it in its flow.

A solution Sweeney discussed is to plant vegetation along the banks of the river to prolong the life of the reservoir.

“Mark does an excellent job explaining how lakes like Lewis and Clark near Yankton are affected by years of downstream sediment accumulation,” said Michael Ewald, host of Credit Hour. “While the problem may take years to grow, it has the potential to impact hydroelectric power generation, recreation and natural river environments and habitat."

Credit Hour is available on Apple podcasts, Stitcher, Google Play and


Founded in 1862 and the first university in the Dakotas, the University of South Dakota is the only public liberal arts university in the state, with 202 undergraduate and 84 graduate programs in the College of Arts & Sciences, School of Education, Knudson School of Law, Sanford School of Medicine, School of Health Sciences, Beacom School of Business and College of Fine Arts. With an enrollment of nearly 10,000 students and more than 400 faculty, USD has a 16:1 student/faculty ratio, and it ranks among the best in academics and affordability. USD’s 18 athletic programs compete at the NCAA Division I level.


Hanna DeLange
USD News