Tunnel and Reservoir Plan
The Tunnel and Reservoir Plan (abbreviated TARP and more commonly known as the Deep Tunnel Project or the Chicago Deep Tunnel) is a large
History
19th century
The Deep Tunnel Project is the latest in a series of civil engineering projects dating back to 1834. Many of the problems experienced by the city of Chicago are directly related to its low level topography and the fact that the city is largely built upon marsh or wet prairie. This combined with a temperate wet climate and the human development of open land, leads to substantial water runoff. Lake Michigan was ineffective in carrying sewage away from the city, and in the event of a rainstorm, the water pumps that provided drinking water to Chicagoans became contaminated with sewage. Though no epidemics were caused by this system (see Chicago 1885 cholera epidemic myth), it soon became clear that the sewage system needed to be diverted to flow away from Lake Michigan in order to handle an increasing population's sanitation needs. [dubious ]
Between 1864 and 1867, under the leadership of
In 1871, the deepening of the Illinois and Michigan Canal was completed to reverse the flow of the Chicago River to drain diluted sewage southwest away from Lake Michigan. However, the canal only had the capacity to drain to the Des Plaines River during dry weather; during heavy rains, the Des Plaines would flood and overflow into the canal, reversing its flow back into the lake.[4] In 1900, to improve general health standards, the flow of the main branch of the Chicago River was permanently reversed with the construction of the Chicago Sanitary and Ship Canal. This further improved the sanitation of Lake Michigan and helped to prevent further waterborne epidemic scares.
20th century
The construction of the
Surrounding farmland also engaged in flood control projects. The Illinois Farm Drainage Act of 1879 established drainage districts. These districts were generally named for the basin they drained—for example, the Fox River Drainage District. After World War II, suburban communities began to realize the benefits of separating stormwater from sewage water and began to construct separate sewer and storm drainage lines. The primary benefit of wastestream separation is that storm water requires less treatment than sewage before being returned to the environment.
Flood damage grew markedly after 1938, when surrounding natural drainage areas were lost to development and human activity. Serious flooding has occurred in the Chicago metropolitan area in 1849, 1855, 1885, 1938, 1952, 1954, 1957, 1961, 1973, 1979, 1986, 1987, 1996, 2007, and 2008—but most record-setting
In the 1960s, the concept of Deep Tunnel was studied and recommended as a solution to continuing flooding issues.
Status
Phase 1, the creation of 109.4 mi (176.1 km) of drainage tunnels ranging from 9 to 33 ft (2.7 to 10.1 m) in diameter, up to 350 ft (110 m) underground, was adopted in 1972, commenced in 1975, and completed and operational by 2006. Phase 2, creation of reservoirs primarily intended for flood control, remains underway with an expected completion date of 2029. Currently, up to 2.3×10 9 US gal (8.7×10 9 L) of sewage can be stored and held in the tunnels themselves while awaiting processing at sewage treatment plants, which release treated water into the Calumet and Des Plaines rivers.[5]
Additional sewage is stored at the 7.9×10 9 US gal (30×10 9 L) Thornton Composite Reservoir, and the 350×10 6 US gal (1,300×10 6 L) Gloria Alitto Majewski Reservoir near O'Hare International Airport. The 3.5×10 9 US gal (13×10 9 L) McCook Reservoir was completed in 2017 and will be expanded to 10×10 9 US gal (38×10 9 L) by 2029.[6][7] Because the reservoirs are decommissioned quarries, construction has been delayed by decreased demand for the quarried gravel. Upon completion, the TARP system will have a storage capacity of 17.5×10 9 US gal (66×10 9 L).
Reservoirs
Name | Location | Coordinates | Maximum Capacity (gallons) |
Status | Notes |
---|---|---|---|---|---|
Gloria Alitto Majewski Reservoir | Elk Grove Village, IL
|
42°01′03″N 87°56′42″W / 42.01750°N 87.94500°W | 350,000,000 | Completed in 1998.[8] | |
McCook Reservoir | McCook, IL
|
41°46′22″N 87°50′24″W / 41.77278°N 87.84000°W | 3,500,000,000 | First phase completed in 2017.[9] | Second phase will expand the reservoir's capacity to 10 billion gallons by 2029. |
Thornton Composite Reservoir | Thornton, IL
|
41°34′55″N 87°37′05″W / 41.58194°N 87.61806°W | 7,900,000,000 | Completed in 2015. | Formerly part of Thornton Quarry. |
Effects
Severe weather events have forced water management agencies to pump excess wastewater into the lake and river in order to prevent flooding. These incidents have decreased in frequency as more of the Deep Tunnel system has become operational. Long considered an open sewer, the Chicago River now hosts more than 60 fish species and increased wildlife along its shores. Substantial development is occurring along many portions of the riverfront. Canoeing is once again allowed on the waterway, but swimming is still prohibited due to high pollution levels.
On October 3, 1986, a heavy thunderstorm drenched the southern portion of the Deep Tunnel area with several inches of rain in a short period of time. While the Deep Tunnel system performed satisfactorily by absorbing excess water, water within the system itself rushed past the north side of Chicago and near the
During the
Since the tunnels became operational, combined sewer overflows have been reduced from an average of 100 days per year to 50. Since Thornton Reservoir came online in 2015 combined sewer overflows have been nearly eliminated.[11]
Sources
- Horan, Deborah (March 14, 2005). "Deep Tunnel, Deep Ties". Chicago Tribune. Retrieved 2021-08-04.
- "Featured Underground: TARP Torrence Avenue Tunnel". American Underground Construction Association. August 1999. Archived from the original on 2000-08-23. Retrieved December 23, 2005.
- "Deep Tunnel Project". Village of South Holland. Archived from the original on 2013-09-19. Retrieved December 23, 2005.
- Schmidt, Elaine (August 2004). "Chicago's Tunnel, Reservoir Plan". McGraw-Hill Construction. Archived from the original on 2011-07-17. Retrieved December 23, 2005.
- "Tunnel and Reservoir Plan (TARP)". The Metropolitan Water Reclamation District of Greater Chicago. Retrieved July 30, 2021.
- Jones, Steve; Waller, John (2006). Down the Drain Five: Deep Tunnel (Report). Chicago Public Library. Archived from the original on 2007-09-29.
References
- ^ Lydersen, Kari (2011-05-17). "Chicago River on National Endangered List". Chicago News Cooperative. Archived from the original on 15 March 2012. Retrieved 2011-06-06.
- ^ Sanders, Steve (2005-10-10). "WGN-TV CoverStories: Deep Tunnel". WGN-TV. Archived from the original on 2005-11-05. Retrieved 2005-12-23.
- ^ Chicago Department of Public Works. Chicago Public Works: A History. 1973.
- ^ Capano, Daniel E. "Chicago's War With Water: On its way to pioneering our modern sewer system, Chicago survived epidemics, floods, and countless bad plans". www.inventionandtech.com. American Heritage's Invention & Technology. Retrieved 4 August 2023.
- ^ "TARP at 50: How one of the world's largest public works projects for water has protected the Chicago region" (PDF). Metropolitan Water Reclamation District of Greater Chicago. 31 October 2022. Retrieved 7 June 2023.
- ^ Hawthorne, Michael (December 4, 2017). "McCook Reservoir to open soon, holding sewage and runoff until storms pass". Chicago Tribune. Archived from the original on 2018-11-30. Retrieved 2018-11-29.
- ^ "McCook Reservoir to Greatly Boost Flood Storage Capacity". Tunnel Business Magazine. January 1, 2018. Archived from the original on 2018-11-30. Retrieved 2018-11-29.
- ^ "Massive New Reservoir To Help Alleviate Chicago Area Flooding". CBS Chicago. 1 September 2015. Archived from the original on 3 September 2019. Retrieved 28 August 2019.
- ^ Meincke, Paul (4 December 2017). "McCook Reservoir opens, seeks to alleviate flooding". ABC Chicago. Archived from the original on 3 September 2019. Retrieved 28 August 2019.
- ^ Karwath, Rob (1986-10-17). "Tunnel's Geyser Effect Still Puzzling". Chicago Tribune. Archived from the original on 2018-08-04. Retrieved 2017-07-04.
- ^ "TARP Fact Sheet" (PDF). Metropolitan Water Reclamation District of Greater Chicago. n.d. Retrieved 22 March 2023.