Modeling Sediment Dynamics St. Croix River

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Recent studies have shown that junvenile mussel density is decreasing in native mussel communities that harbor Federally-listed mussel species. These declines have been accompanied by increased fine sediment deposition at these locations in the St. Croix National Scenic Riverway. One location is listed as an Essential Habitat Area in the Higgins Eye Recovery Plan. Other monitoring sites on the river have not experienced the decline in juvenile mussels or in sediment fining. Sites that have experienced declines are found in a ten-mile stretch of river downstream of the hydroelectric dam at St. Croix Falls, Wisconsin. We will develop a model decribing the relationship between discharge and sediment transport, monitor suspended sediment transport, and examine sediment cores from the reservoir above the dam as well as the forces of shear-stress above and below the dam.

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