I just read _The Great River_ by Boyce Upholt, a history of the Mississippi river and human management thereof. It was funny how the railroads were used as a bo

I just read _The Great River_ by Boyce Upholt, a history of the Mississippi river and human management thereof. It was funny how the railroads were used as a bogeyman to justify continued building of locks, dams, and other control structures on the Mississippi and its tributaries, long after shipping commodities down river had been supplanted by the railroads.