Cloudy Waters: USU Scientist Studies Minnesota's Le Sueur River

Ever wonder why most buttons have a pearlescent appearance? It’s because today’s buttons, usually made of plastic, are modeled after buttons of old made from freshwater mussels.

 

During the late 19th century, German-born button maker Johann Böpple pioneered the manufacture of buttons from mussels collected from the upper Mississippi River Valley. The industry thrived well into the mid-20th century, providing an important source of jobs for people throughout the region, including residents of the Minnesota River Basin.

 

But no more, says Utah State University researcher Patrick Belmont, who has studied streams and rivers in the basin since 2007. Populations of freshwater mussels began to decline in the mid-1900s due to such factors as over-harvesting, dams and other diversions that caused sediment loading and altered habitats, along with runoff and pollution from agriculture and industry.

 

“The Minnesota River and its tributaries have an unusually heavy sediment load,” says Belmont, an affiliate scientist with the National Science Foundation-funded National Center for Earth-surface Dynamics. “Working with state agencies, agricultural producers and private industry, we’re trying to find out why.”

 

Belmont, who joined USU’s Department of Watershed Sciences as an assistant professor in Dec. 2009, is developing a sediment budget for southern Minnesota’s Le Sueur River, a tributary of the Blue Earth River and, subsequently, the Minnesota River.

 

Developing a sediment budget is a challenge, he says, because measuring where the sediment comes from and the amount of sediment is complicated.

 

“We have to measure how much sediment is contributed from agricultural fields and streambanks and how much is deposited and stored in floodplains,” Belmont says. “These measurements are tricky but we’re approaching them with new, innovative approaches.”

 

Among the tools Belmont will use are global positioning system technology with centimeter accuracy, 3-D cameras and scanners that precisely document year-to-year erosion and deposition, along with geochemical tracers that fingerprint sediment sources.

 

Since recorded history, the region’s rivers have always been muddy. The name Minnesota comes from a Dakota word that roughly translates as “water reflecting a cloudy sky.” Yet the stripping of native vegetation and draining of wetlands to allow farming and community development has accelerated erosion, resulting in degraded aquatic habitats and polluted waters deemed unsafe for swimming, boating and fishing.

 

Despite its impaired status, people want to live on the river, he says. Over the last 13,000 years, the lower reaches of the Le Sueur have cut through the flat, plains landscape, leaving nearly vertical 60 to 100 feet-high bluffs. Waterfront homes provide a beautiful view but often require expensive retaining walls.

 

“There’s a lot of finger pointing and disagreement about how much sediment is normal and healthy for the river,” says Belmont, whose research, in addition to the NSF, is funded by the Minnesota Pollution Control Agency and the Minnesota Department of Agriculture. “But there’s also a lot of interest in rehabilitating the river.”

 

Along with his Minnesota research, Belmont is studying erosional processes in eastern Idaho’s Lemhi Range and California’s Death Valley.

 

At Utah State, he looks forward to teaching and conducting research with access to USU’s Luminescence Laboratory, which offers optically stimulated luminescence dating capabilities.

 

“It’s great to be at Utah State where there’s a lot of geomorphology research involving varied disciplines,” Belmont says. “There’s no shortage of interesting questions to pursue.”

 

 

Contact: Patrick Belmont, 435-797-3794, patrick.belmont@usu.edu