The river that was made to flow the other way

In 1887 it was decided to attempt a bold engineering feat and reverse the flow of the Chicago River. Rudolph Hering, chief engineer of the drainage and water supply commission, noted that the Great Lakes drainage system was separated from the Mississippi River drainage system by a summit or ridge approximately 8 feet high located some 12 miles west of the lake shore. A plan was evolved to cut through that ridge with a canal from the southerly tip of the south branch of the Chicago River and carry the wastes away from the lake and down to the Mississippi River through the Des Plaines and Illinois rivers. The Metropolitan Sanitary District of Greater Chicago was created in 1889 under a law passed by the state legislature to effect this plan.

To reverse the flow of the Chicago River, a 28-mile canal was built from the south branch of the river through the low summit and down to Lockport. It was completed in 1900. The flow in this canal, commonly known as the Sanitary and Ship Canal or main channel, is controlled by locks at the mouth of the Chicago River and at Lockport. Thus, Chicago had built the first of its own rivers to dispose of waste waters.