By Arlan Juhl, P.E., Office of Water Resources
The Chicagoland area is topographically dominated by the glacial Lake Chicago plain encompassing the Chicago River, Des Plaines River, and the Calumet River. Early explorers discovered the Chicago Portage, an area within Mud Lake which was only 15 feet above the level of Lake Michigan and on the watershed divide between the Mississippi River basin and the Great Lakes basin.
The Chicagoland area experienced many early drainage challenges. The natural condition was swampy and Chicago streets were poorly drained and muddy. The level of Lake Michigan was only two feet below the river banks, making subsurface drainage ineffective. Sewage discharged into the Chicago River created health hazards for the region.
In 1834, the first attempt to solve the sanitation problem of Chicago included a drainage ditch dug down State Street and emptying into the Chicago River. Later, the City of Chicago raised streets, then buildings eight to ten feet above natural ground level. This helped to drain the streets and to get the sewage to the river more efficiently, but the river could not cleanse itself of the sewage due to the high level of Lake Michigan.
The Illinois and Michigan Canal was authorized by Congress on March 2, 1827. The canal had a summit level eight feet above lake level, with water being supplied to the summit level from
1) the Calumet Feeder Canal bringing Little Calumet River water through Sag Valley and Ausaganaskee Swamp to the summit level at Sag Bridge,
2) the Des Plaines River (the canal and the Des Plaines River ran together at Sag Bridge, but the river supplied little water during low flow), and
3) two steam pumps at Bridgeport which could lift about 100 cubic feet of water per second from the South Branch Chicago River to the summit level. The Illinois and Michigan Canal, completed in 1848, flowed from present day Summit to LaSalle. From 1861 through 1870, the City of Chicago paid to operate the Bridgeport pumps an additional 45 days per year to flush sewage from the Chicago River and away from the lake. Between 1867 and 1871, the city deepened the canal between Bridgeport and Lockport to eliminate the summit level, providing gravity flow from the lake to Lockport at the rate of 160 to 550 cubic feet per second. The first recorded reversal of the Chicago River flow was in 1871.
The 1872 flood diverted almost all the Des Plaines River flows into the Chicago River through the Ogden-Wentworth Ditch, causing significant pollution within the Chicago River when the sewage could no longer be sent downstream. A dam was constructed across OgdenWentworth Ditch to prevent future diversions of Des Plaines River flows.
A new steam pump and guard lock was installed at Bridgeport in 1884, reestablishing the summit level. Pumping capacity was 1,000 cubic feet per second at normal lake level. At the request of Indiana, the Calumet Feeder had been abandoned and the Little Calumet River dam removed in 1874. The Bridgeport pumps were the main source of water to the canal until 1900, averaging 500 cubic feet per second.
In 1885. a large rainfall washed sewage and refuse out of Chicago and the Chicago River into Lake Michigan, polluting the cities water supply. In 1887 the Drainage and Water Supply Commission recommended a major plan for collecting and disposing of Chicago's sewage.
The Illinois General Assembly authorized the establishment of the Sanitary District of Chicago in 1889 to implement the construction of the Sanitary and Ship Canal to carry away waste from the city and to dilute it as it flowed downstream. Construction began in 1892, and flow through the Sanitary and Ship Canal began January 17, 1900. The North Shore Channel enlargement, begun in 1907and completed in 1910, diverted more lake water to aid in dilution, and the Chicago River was enlarged in 1912. Construction of the Cal-Sag Channel began in 1911 and was completed in 1922, causing the reversal of flow in the Calumet River away from Lake Michigan. A Supreme Court decree in 1933 ordered the construction of the Chicago River lock and controlling works which was completed in 1938. The Chicagoland area outside of the City of Chicago experienced many drainage alterations as well. Much of the South Branch Chicago River and the Little Calumet River basins were poorly drained in their natural setting. Agricultural and developmental interests constructed miles of drainage ditches, constructed as 'parallel ditches" with the excavated material being deposited between the ditches to be used as roadways.
The Farm Drainage Act of 1879 established the authority to create drainage districts, marking the beginning of a period of significant drainage modifications in agricultural areas. The number of drainage districts and the acreage served by these districts grew rapidly. By 1929, 88 drainage districts covered 177,595 acres of the Chicago River, Little Calumet River, Des Plaines River, DuPage River and Fox River basins. By 1971, 180 drainage districts were listed in an "Inventory of Drainage and Levee Districts" within Cook, DuPage, Lake, McHenry, Kane and Will Counties.
As more land became developed with housing, streets and shopping areas, a greater amount of runoff from this developed ground ran to the sewers. Sewers became overloaded and frequently backed up into low areas, basements and underpasses, then over-flowed to the local streams, carrying polluted waters with it. The storm water runoff, mixed with sanitary sewage and became combined sewage, a large and difficult problem in the Chicagoland area. Suburban communities which developed after World War II realized the value of separate sewer systems to handle sanitary sewage and stormwater runoff. Suburban communities have installed countless miles of storm sewers to accommodate the modern drainage needs of the communities and replacing the drainage systems provided by drainage districts. Most storm sewer systems are able to handle the runoff from low intensity rainfall events before the area begins to show its historically swampy nature.
Studies in the late 1960's recommended the Tunnel and Reservoir Plan (TARP) as a means to solve this problem. TARP tunnels include the Mainstem, Calumet, Des Plaines and Upper Des Plaines systems, totally 109 miles of tunnels. These tunnels capture 85% of the combined sewer over-flows which had been discharging into the rivers and streams. TARP's three reservoirs , when completed, will provide significant flood control and eliminate the remaining 15% of combined sewer over-flows.
Flooding of rivers in the Chicagoland area is a natural phenomenon. Agricultural areas flooded along with natural wetlands. The magnitude of these floods and the effects upon man grew as the metropolitan area developed. Flood events of historical significance have occurred across the region during 1848, 1855, 1885, 1938, 1952, 1954, 1957, 1961, 1973, 1979, 1986, 1987, and 1996. Most record setting flood stages and discharges in the region have been recorded since 1948.
Flood control and watershed planning in the Chicagoland region is managed by a group of federal, state and local agencies. These include the U.S. Army Corps of Engineers, the U.S,D.A., Natural Resource Conservation Service, the U.S. Environmental Protection Agency, the Illinois Department of Natural Resources, Office of Water Resources, the Metropolitan Water Reclamation District of Greater Chicago, the Cook County Stormwater Management Committee, the DuPage County Stormwater Management Division, the Kane County Department of Environmental Management, the Lake County Stormwater Management Commission, the McHenry County Stormwater Management Division, and the Will County Stormwater Management Division.
By the early 1980's several watershed plans were developed to address flood problems along the North Branch Chicago River, Upper Des Plaines River, Lower Des Plaines Tributaries, Poplar Creek, Upper Salt Creek and the Little Calumet River. When completed, these plans will have resulted in the implementation of 43.9 miles of channel modifications and 41,128 acre-feet (1 3.4 billion gallons) of floodwater storage facilities, including the Tunnel and Reservoir Plan. Flooding remains a serious problem along the main channel of the Des Plaines River and the Little Calumet River and many smaller Chicagoland streams. A 1998 estimate puts annual flood damages at $41,459,000 in the Chicagoland area, affecting nearly 20,000 homes and businesses.
Local, state and federal agencies and individuals have become increasingly aware of the unmitigated impacts of urbanization on drainage and flooding. The Metropolitan Water Reclamation District implemented the first stormwater detention ordinance in 1972. This ordinance required new developments to detain a portion of the increased runoff and to restrict the outlet capacity of the detention basin to a predevelopment discharge. In the Chicagoland area it has now become standard practice to provide stormwater detention within new subdivisions to control the rate of runoff to predevelopment rates. However, as new rooftops and parking lots are constructed, the previously permeable soil can no longer absorb rainfall, increasing the volume of stormwater to be drained from the land. The streams, forced to carry increasing volumes of runoff, flood and create renewed interests in watershed management. Record-setting floods occurred throughout the region in 1986 and 1987. The 1986 flood was triggered by widespread regional rainfall with varying intensity and duration which had been preceded by two weeks of nearly continuous rain falling across northern regions of the Des Plaines, North Branch Chicago, and Fox River watersheds. Flooding in rivers and streams across Lake, McHenry, northern Cook, northern DuPage and northern Kane Counties resulted. The 1987 flood was generated by localized, high intensity and shorter duration rainfall which dropped up to 13 inches of rainfall in some regions in less than 24 hours. This rainfall was concentrated across Cook and DuPage counties. Record river stages and flows were recorded throughout the northeastern Illinois region during the 1986 and 1987 flood events. Flood damages were great, leaving many residents and motoring public stranded and without access to services. The 1986 and 1987 floods generated enough public awareness of the continued problems of drainage and flooding for the Illinois General Assembly to pass legislation authorizing the formation of countrywide stormwater management programs. Such programs, in conjunction with state and federal programs, are providing stormwater management planning, watershed planning, regulation of construction within floodplain areas, and new sources of funding to manage local drainage and flooding problems.
"The Metropolitan Water Reclamation District of Greater Chicago", a pamphlet describing the duties and projects of the Metropolitan Water Reclamation District of Greater Chicago.
"Sanitary Strategy for a Lakefront Metropolis, The Case of Chicago", Louis Cain, Northern Illinois University Press, 1978
"Lake Diversion at Lake Michigan", Bruce Barker, P.E., Illinois Department of Transportation, Division of Water Resources. 1985
"Engineering and Legal Aspects of Land Drainage in Illinois", G.W. Pickels and F. B. Leonard, State of Illinois, Department of Registration and Education, Division of State Geological Survey, Bulletin No. 42, 1929
"The Sanitary District of Chicago: A Case Study of Water Use and Conservation", Louis Perkins Cain, 111, Northwestern University, June, 1969
"History of Chicago from the Earliest Period to the Present Time", Volume 1, A.T. Andreas, 1884
"History of Chicago, Historical and Commercial Statistics", William Bross, 1876
"In The Supreme Court of the United States, October Term 1966, Report of Albert B. Marris, Special master", December 8, 1966