Laura Triplett

| Geology

John Leaf '09 collecting sediment from a bluff along the LeSueur River in 2008.

Sources of sediment in the Minnesota River

Sediment eroded from the Minnesota River watershed is a major contributor to water quality impairment downstream in the Mississippi River and Lake Pepin. Traditional thinking was that most of this sediment was eroded from agricultural fields, but there is new evidence that sediments eroding from stream channels, ravines and bluffs are much more signficant sources. 

In one project, we used the geochemical signatures of sediment in the LeSueur River watershed to attempt to differentiate topsoil from streambank and bluff sediment, and to thereby quantify the relative importance of those two potential sediment sources.  In other work, we are monitoring flow and sediment fluxes in streams and ravines to better understand geomorphic and hydrologic processes controlling sediment mobilization