Civil Engineering Details of the Canal
Plans were drawn up to construct a canal 28 miles long, 202 feet wide and 24 feet deep connecting the Chicago River and the Des Plaines River. Locks were also planned at the two places where the Chicago River met the Michigan lake so that water inflow in to and out of the lake could be controlled. Besides river dredging and canal building, the work also involved construction of roads and bridges. A fifteen mile stretch of the canal was through rock and had to be removed by dynamite. Steams shovels mounted on rails were used to remove the debris from the blasting operations.
Altogether 43,000,000 cubic yards of stone and dirt were excavated over a period of eight years from the main canal itself and at a cost of $70 million. Most of the labor used on the project involved people of African-American origin; at least that is what photographic records of the day seem to suggest. Equipment used was mechanical shovels and excavators and even ropeways to remove the dirt and stones. A lot of the techniques perfected by the engineers of the time were used in operations for making the Panama Canal following the completion of this canal. The Army Corp of Engineers had responsibility for most of the works on the canal.
Thirteen bridges were also built over the canal. They were all movable bridges so that canal boats could pass through. Seven sluice gates each thirty feet wide were built at Lockport to regulate the amount of water flowing through the main canal. A 160-foot dam that was also movable was part of this construction.
The vertical height of the dam was 17 feet, and it consisted of two huge iron sheet plates joined by hinges. The lower plate was firmly anchored, while the upper one could be raised or lowered according to requirement. The power used for this mechanism was through special conduits and valves that used the power of the water current. This ingenious mechanism was a source of wonder to engineers the world over.
Image Source: Wikimedia: Canal and Bridges