The Chicago River: A Transnational Matrix of Place

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The Chicago River is one of those little rivers that has a big history. This is largely because a megalopolis grew up around it. Indeed, the humble fluvial characteristics of this river belie what we call a “technological matrix of place.” In this post, we’ll discuss some of the themes we explored in a recently published chapter.[i] We examine three infrastructural networks that intersect at the Chicago River: the Chicago Diversion, Enbridge’s Lakehead pipeline system, and the electric fish barrier system. 

ASEH field trip along the Chicago River at ASEH 2017. Photo by Daniel Macfarlane.

All three of these matrices are meant to be largely unseen and are emblematic of “disguised design”. Yet, though they intersect at discrete places at or in the Chicago River, these matrices are also part of enormous border-spanning networks that affect the flows of water, fossil fuels, and invasive species across the continent. 

Matrix #1: Chicago Diversion

The Chicago River was famously reversed in the last decade of the nineteenth century. This was done as part of creating the Chicago Sanitary and Ship Canal.[ii] The main purpose was to shunt disease-causing polluted water south – by withdrawing water from Lake Michigan and sending it across the Great Lakes hydrological divide to the Mississippi River basin. The “Chicago Diversion” referred to the volume of water the city could legally withdraw, with the canal capable of up to 10,000 cubic feet per second (cfs).

Canada and the U.S. Great Lakes states have strenuously objected to the Chicago Diversion since it opened. They argued that it lowered Great Lakes water levels. This required hydroelectric works, such as those at Niagara Falls, to compensate. Deeper dredging became essential for industrial shipping in rivers like the St. Clair and Detroit. 

Construction of the Chicago Sanitary and Ship Canal in the 1890s.

The diversion became a perennial thorn in U.S.-Canadian diplomacy. It factored into negotiations over the 1909 Boundary Waters Treaty, and was part of the reason that this treaty didn’t include Lake Michigan. Between 1912 and 1924 Canada filed six diplomatic objections to the diversion, and it factored into the defeat of the Great Lakes Waterway Treaty of 1932. To compensate for lower levels in the lower lakes, Ontario built the Ogoki-Long Lac diversions.

In the 1950s, the Chicago Diversion reared its head during the negotiations for the St. Lawrence Seaway and Power Project.  The US Supreme Court eventually lowered the diversion limits, but the matter remained a political football. More recently, Illinois’s refusal to consider any changes to the diversion nearly sank a decade of negotiations for the 2008 Great Lakes–St. Lawrence River Water Resources Basin Compact. 

Such iterative actions and reactions make visible an underwater infrastructure matrix in which a technological “butterfly” flapping its wings in one place had distant hydrological, political, and economic impacts elsewhere in the system.

Matrix #2: Enbridge Pipelines

Like water flows from the Chicago Diversion, oil flows through the Chicago region are mostly invisible. At the canal near the Chicago suburb of Romeoville, Enbridge pipeline 6A makes a rare above ground appearance. 

Pipeline 6A arching over the waterway. Photo by Lynne Heasley.

6A is part of a latticework of North American pipeline infrastructure taking oil from Alberta to the Great Lakes region and beyond. From the Canadian prairies, Enbridge’s main line runs to the far western tip of Lake Superior. There the Lakehead system forks into Line 5 and Line 6A (built in 1953 and 1960 respectively).

Line 6A is Enbridge’s largest oil artery supplying its U.S. market. Line 6A goes southeast through Wisconsin and Illinois. Near the Chicago Sanitary and Ship Canal, 6A runs underground, then soars briefly over the canal as aerial pipes. In April 2010 at Romeoville, municipal employees, rather than Enbridge itself, discovered a six thousand barrel spill from Line 6A. 

Map of pipelines in the. Great Lakes region, by Jason Glatz (WMU Libraries)

Line 6A ends southwest of the canal at Griffith, Indiana. From there its sister line, 6B, continues on through Michigan, passing under the St. Clair River to Sarnia, Ontario. Line 6B was the infamous pipeline of the July 2010 Enbridge oil spill into a tributary of the Kalamazoo River – over 1.2 million gallons of tar sands dilbit (incidentally, this was the second-largest inland oil spill in US history, and took place just east of where the authors of this post live). Line 5, for its part, infamously runs under Michigan’s magnificent Straits of Mackinac (though the Michigan Governor has ordered this closed in 2021). 

These canal, straits, and rivers are among the thousands of places where oil crosses above or beneath water. Each is a submerged technological matrix, a vulnerable hybrid of engineered and natural hydrological systems. Collectively they form an interconnected network in which leaks and spills are the norm

Matrix #3: Asian Carp Barriers

The Chicago Sanitary and Ship Canal was built to send pollution south to the Mississippi. But now a different type of pollution threatens to move in the opposite direction. The “biological pollution” in question is Asian Carp. Since the 1970s, they’ve migrated up the Mississippi River system, decimating aquatic food webs along the way. In many parts of the Mississippi basin, silver and bighead carp constitute up to 95 percent of the total aquatic biomass. (And silver carp famously jump out of the water when startled).

Fish barrier. Photo by Lynne Heasley

What stands between these invasive fish and the Great Lakes? Electric barriers in the Chicago Sanitary and Ship Canal. Built by the U.S. Army Corps of Engineers, these electrified fish barriers form another disguised infrastructure, a matrix at once powerful and vulnerable.

Smith-Root, Inc. was the Corps’ sole contractor to design and build the dispersal barrier system.  This company accidentally stumbled onto the fish deterrence technology decades ago. From 1988 through 2016, Smith-Root filed six patents for some version of electric dispersal fish barrier systems. 

As the barrier prototypes evolved, controlling the fish depended on the precise application of current running through water. This in turn depended on intimate knowledge of how electricity passes through a moving animal’s body and shapes its behavior. For instance, in their 2005 patent, the team noted problematic aspects of electricity–fish interfaces: “Because a fish has salts and electrolytes within its body . . . a fish’s body acts as a ‘voltage divider’ when swimming through fresh water.”[iii] Precision could never be wholly achieved, because these were real-world uncontrolled experiments.

Diagram of barrier patent. Source: U.S. Army Corps of Engineers

It turned out that juvenile fish could withstand a higher level of pain. Over and over they probed and tested the barriers, finding less discomfort closer to the surface and toward the canal edges. Acoustic bubbles or bubble barriers near canal walls might address this particular vulnerability. But there were other potential ways for the fish to get through or around, such as drafting along with barges and vessels.

Map of Chicago Waterway System and Barriers. By Jason Glatz (WMU Libraries)

Today the system consists of barriers placed at intervals in the canal near Romeoville, Illinois. Barrier I had been tried on a demonstration basis starting in 2002. Barrier IIA became operational in 2009, and IIB in 2011. The Trump administration put on hold the Corps’ proposal for another electric barrier farther south. Asian Carp are now within just a few miles of Lake Michigan, and eDNA has been found in the lake. It’s just a matter of time until the fish get in – and then likely spread across the basin and ravage food webs. The safer, longer-term solution would be to re-separate the Mississippi and Great Lakes basins. 


In Nature’s Metropolis, William Cronon’s classic study of nineteenth-century Chicago, the city was the gateway through which railways and shipping lanes funneled and dispersed commodities.[iv] The three matrices we explore have a similar metropolitan-hinterland relationship. But pipelines and canals moving fossil fuels, fish, and water – rather than railways moving pork and lumber – constitute the visual spiderweb taking commodities in and out of the Windy City. 

Cronon also posited a “second nature,” a city built from nature transformed. Since then, a robust envirotech scholarship has approached landscapes and waterscapes as intertwined hybrids of nature and technologies. This is certainly the case for the Chicago River, where boundaries between the natural world and technology are porous; where water, oil, and fish were built into the infrastructures of canal, pipeline, and barrier; and where the infrastructure itself became part of a multidisciplinary scientific enterprise. 

Section where the electric barriers, diversion, and Pipeline 6A intersect. Photo by Daniel Macfarlane.

By design, however, these water diversions, buried pipelines, and fish barriers are unseen. Disguised infrastructures have virtues. But they also submerge risk. The risk is that something supposedly confined and safe will escape its scripted boundaries. Those taking risks with hydrology, oil spills, and aquatic ecosystems won’t have to bear the full brunt of disasters. Any economic or ecological fallout will be at once highly localized and widely regionalized. 

[i] This chapter can be found in the 2020 edited collection titled City of Lake and Prairie: Chicago’s Environmental History.

[ii] On the dyeing of the Chicago River green for St. Patrick’s Day, see this 2017 NiCHE post.

[iii] Smith-Root, Inc. [inventors David V. Smith and Lee Roy Carstensen], Electric Fish Barrier for Water Intakes at Various Depths, U.S. Patent US6978734 B1, December 27, 2005.

[iv] William Cronon, Nature’s Metropolis (New York: W. W. Norton, 1992).

Feature image by Daniel Macfarlane.

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Daniel Macfarlane & Lynne Heasley

Daniel Macfarlane and Lynne Heasley are both professors in the Institute of the Environment and Sustainability and Western Michigan University. Together they edited "Border Flows: A Century of the Canadian-American Water Relationship."

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