The monumental feat of reversing the flow of the Chicago
River, so that it now flows from Lake Michigan into the Mississippi,
involved not only canal building, but also river dredging and bridge and
road building. The final 15 miles were dug through rock with the help of
dynamite and steam shovels mounted on rails in the trench to remove the
debris. This digging technique was adopted a few years later in the Panama
Canal dig.
Extensive dredging of the Chicago River was also required
in order to reverse its flow. When the canal's gates were opened at
Lockport in January 1900, the river changed its direction as planned and
sewage stopped flowing into Lake Michigan. Dilution and natural biological
processes were adequate to render the sewage harmless to downstream
communities until the 1920s, when treatment plants were constructed. The
Sanitary and Ship Canal continues to carry drainage and barge traffic,
operating as originally conceived.
