As part of a series of stories following the path of the "Father of Waters,” aka the Mississippi River, Minnesota Public Radio's Art Hughes has this Mainstreet report on the he U.S. Army Corps, which vigorously controls the river in the southeastern part of Minnesota. That has come at a environmental cost…a loss of diversity.

The U.S. Army Corps of Engineers (CORE) is the primary controlling force for the Mississippi River between St. Paul and the Gulf of Mexico. The corps first constructed a series of rock structures, then larger, more efficient dams and locks, all to keep barges moving unobstructed. For a century and a half, the river's flow has been directly manipulated by human hands. Now, as environmental consequences become more and more obvious, agencies and individuals are struggling to find ways to strike a balance between commerce and ecology.