Forest Preserve District of Cook County, Illinois
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The Des Plaines River -- Part One
Nature Bulletin No. 606   May 28, 1960
Forest Preserve District of Cook County
Daniel Ryan, President
Roberts Mann, Conservation Editor
David H. Thompson, Senior Naturalist

Chicago was incorporated as a village in 1833 and in less than 100 years it had become one of the world's great cities. Four unique natural features have contributed to its phenomenal growth.

The first is Lake Michigan. Chicago is strategically located at the south end of it, deep in the heart of the continent and the vast central lowland -- bread-basket of our nation. The lake provides an inexhaustible supply of fresh water and a highway for water-borne commerce. Since the completion of the St. Lawrence Seaway, Chicago has also become a port for ocean going ships.

The second is the broad, remarkably flat Chicago plain that, originally, was the bed of Lake Chicago -- glacial ancestor of Lake Michigan. When its swamps and wet prairies were properly drained this plain became ideal for industrial, commercial and residential developments.

The third is a low continental divide between the St. Lawrence and Mississippi drainage systems. Northeast of Summit it is only 15 feet above the level of Lake Michigan. Drainage of the Chicago Plain, and an outlet other than Lake Michigan for the city's sewage, and a deep waterway to the Illinois River, were all accomplished by constructing a canal through that divide and utilizing another natural feature: the Des Plaines River.

The Des Plaines is a placid prairie stream that, from swampy sources in Kenosha and Racine counties, Wisconsin, meanders southward through a flat valley roughly parallel to the shore of Lake Michigan. Its most important tributaries are Salt Creek and the Du Page River.

Below River Grove the Des Plaines flows southward -- except for two hairpin bends at Riverside -- across the Chicago Plain until, near Summit, it turns southwest into a deep valley. Mighty torrents from Lake Chicago poured through that valley, and the Sag valley which joins it at Sag Bridge, when the last glacier melted away. That is the Chicago Outlet, one of five great "keys to the continent": the best natural pass to the Mississippi valley.

From U. S. 66 to Romeo the river flows in a diversion channel constructed with a levee to keep it from overflowing into the Sanitary and Ship Canal completed in 1900. From Romeo it flows south and drops 80 feet until, near Joliet, it joins the canal. At Brandon Road lock and dam, south of Joliet, the canal ends and the Des Plaines, widened and deepened as part of the Illinois Deep Waterway, continues southwest until it joins with the Kankakee to form the Illinois River.

Just below U. S. 66 the Des Plaines originally angled southeast. Near Harlem Ave. south of Santa Fe railroad, instead of flowing eastward to Lake Michigan it turned southwest into the Chicago Outlet valley. That area has been designated a national historic site commemorating The Chicago Portage.

East of Harlem Ave. there was a swamp called Mud Lake. That was the Chicago Portage, a route followed by the Illinois and Michigan Canal completed in 1848, by the Ogden-Wentworth Ditch draining Mud Lake, and by two railroads. Occasionally, during floods, the Des Plaines would pour eastward across the low continental divide, through Mud Lake and the South Branch of the Chicago River, into Lake Michigan.

One of those floods in August, 1885, swept so much sewage out into the lake that the city's water supply was terribly polluted and a great many deaths resulted. Shortly after, the Sanitary District of Chicago was established and, in 1892, construction began on the Sanitary and Ship Canal from the South Branch, near Damen Avenue, to Lockport - - 28 miles, much of it through solid rock.

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