Across the top of the map, above the Arctic’s Mer Glaciale, there floats a banner inscribed with a legend that in translation reads “New Discovery of Many Nations in New France in the years 1673 and 1674.” This legend is a bit misleading. Although the terrestrial features seem to have been distorted by a fun-house mirror, the aquatic features are strikingly recognizable and strikingly out of scale, as if we were peering down through a magnifying glass poised over the Great Lakes. Read the semi-legible calligraphic names along the coasts and riverbanks, and you begin to perceive that this isn’t really a map of North America nor of New France. It’s a navigation chart and a relic of a time when waterways assumed out-of-scale proportions in our geographies.
The map was hand-drawn by the explorer Louis Joliet. On the return leg of their 1673 expedition to the Mississippi and back, Joliet and his traveling companion, Père Marquette, made a discovery, a long-sought trade route through the heart of the continent by which — Joliet later reported — “a bark” could sail “by very easy navigation” from “New France” to “Florida,” or as we would put it, from Canada to the Gulf Coast. It is this discovery, this route, that Joliet’s hand-drawn navigation chart illustrates.
There was just one small obstacle to overcome, identified on his map by the word “portage,” written at the site of present-day Chicago. There, at the southwestern tip of Lake Michigan, the explorers had been obliged to lug their cargo and canoes across the “half a league” of prairie separating a tributary of the Mississippi, now known as the Des Plaines River, from the Chicago River, which in 1673 still flowed east into the nearby lake. Joliet, however, had an idea: “It would only be necessary,” he suggested, “to make a canal.” This suggestion would eventually alter the history of the continent, as well as its ecology. We are still reckoning with the consequences in 2015.
Geologically speaking, what the French explorers discovered at the southern tip of Lake Michigan was a low point on the subcontinental divide that for thousands of years had separated the Mississippi Basin from the Great Lakes. Joliet, although he didn’t know it, was proposing to reconnect them.
The canal he imagined exists today, but not for the reasons he suggested it, not exactly. With the arrival of rail, the need for navigable trade routes was less pressing. What Chicago really needed was a sewer. Lacking one, it used the Chicago River, which emptied into Lake Michigan, the city’s water supply. The Chicago Sanitary and Ship Canal (shovel day: Sept. 3, 1892) would connect the Great Lakes to the Mississippi Valley, but it would also reverse the course of the Chicago River, flushing the city’s sewage south. The idea when first proposed seemed a folly, a boondoggle in the making. Reverse a river! You might as well part the waters of Lake Michigan or turn back time. But in low-lying Chicago, the plan’s proponents demonstrated, this miracle of engineering could in fact be performed: Dig a channel deep enough through the subcontinental divide, and gravity would do the rest. Continue reading the main story
The excavation lasted eight years and cost $33 million. On the eve of its completion, word came from St. Louis that attorneys were preparing to petition the Supreme Court, seeking an injunction to shut down the canal before it opened. The trustees of Chicago’s sanitary district responded not with legal actions of their own but by overseeing the destruction by dynamite and steam-powered dredge of the sole remaining barrier holding back the waters of the Chicago River.
Two days later, The Chicago Record delivered good news: “Clear water in the Chicago River — water that was actually blue in color and had blocks of ice of a transparent green hue floating in it — caused people who crossed bridges over the Chicago River yesterday to stop and stare in amazement.” The news from Missouri was gloomier: “Windy City Sewage Now Headed This Way” ran a headline in The St. Louis Star.
The Sanitary and Ship Canal was heralded as a triumph of that heroic age of American civil engineering in which technological progress and industrial might promised to deliver us from nature’s tyranny. If we could reverse the course of rivers, what couldn’t we bend to our will?
In 1955, the American Society of Civil Engineers named Chicago’s sanitation system to its list of seven modern wonders. Also included: the Empire State Building and Hoover Dam. “Man, modern man — the scientist, the explorer, the builder of bridges and waterways and steam engines, the visionary entrepreneur — had become the central creative force,” David McCullough wrote in “The Path Between the Seas,” his history of the Panama Canal (also on the list).
The view from 2015 is muddier. Like many modern wonders, Chicago’s canal solved the problem it was engineered to solve — the city’s sewage crisis — but it did so by sending the consequences downstream, to the Mississippi Valley and, in unanticipated ways, to all of us. In hindsight, it looks less like a triumph of the heroic age of civil engineering than like a prologue to the chastening age we live in now, the epoch geologists have proposed calling the Anthropocene, the age of the sixth extinction. One cause of this extinction: the trade routes and flight paths and navigable waterways with which we stitched continents and basins together. Thanks to us, species that evolved in isolation now collide, at times with devastating effects on ecosystems.
A hundred or so years after it opened, Chicago’s canal has been making news again. “Asian Carp DNA Found in Downtown Chicago, a Block From Lake Michigan” read a typical headline this past January. You’ve most likely seen footage of the slapstick scenes in which boaters motor through a storm of airborne fish. The aerialists in those videos are all silver carp, the only of the four invasive species of Asian carp that exhibits the entertaining fright response so popular on YouTube. Another of the four, the bighead carp, is constitutionally furtive, difficult to catch or detect. By the time the Asian carp footage went viral on the Internet, both species had already gone viral in the Mississippi watershed. Voracious planktivores, they reproduce quickly. Fully grown, they have no natural predators except humans. Commercial fishermen on the Illinois River now catch 25,000 pounds of Asian carp per day, with little discernible effect on the reproducing population. Continue reading the main story Continue reading the main story Continue reading the main story
Ecologists will tell you that it’s impossible to predict just how much havoc the Asian carp might wreak on the ecosystem of the Great Lakes, home to a $7 billion fishery; they will also tell you that we have more than carp to worry about. A 2011 report commissioned by the U.S. Army Corps of Engineers estimates that 87 species in the Great Lakes are at risk of invading the Mississippi and another 57 are threatening to travel in the other direction. They have colorful names: the spiny water flea, the bloody red shrimp, the northern snakehead, the red-rim melania. Those numbers do not include the 103 other species — the round goby, the zebra mussel — for which, according to the report, “any dispersal control mechanism is already too late.”
When dynamite and the steam-powered dredge breached the subcontinental divide in 1900, it also breached thousands of years of evolutionary history. Ecologists and political leaders in Great Lakes states downstream from Chicago argue that as long as the canal remains open, the invasions will continue. The best permanent solution, they say, is “hydroseparation.” In other words, we need to part the waters, restore the continental divide.
Last year, in a much-anticipated report with a misleadingly bland title, “The Great Lakes and Mississippi River Interbasin Study,” the U.S. Army Corps of Engineers affirmed the feasibility of hydroseparation but has yet to make a recommendation to Congress. Whatever recommendation it makes, the very prospect of re-engineering the canal suggests something about the ways our geographies and our own out-of-scale place in them have changed.
“The canal is the only remaining link wanting to complete the most stupendous chain of inland communications in the world,” one visitor to Chicago wrote in 1834. That use of the word “communications” sounds archaic to our ears, but there’s a furtive meaning bottom-dwelling in those etymological channels. Ideas, goods, images, species — everything is communicable now. In shortening distances, we’ve accelerated processes — climatological, evolutionary — to a pace even our own species, the most adaptable, invasive one on the planet, is struggling to keep up with.
Don’t ask just the ecologists. Ask the engineers. Increasingly, it’s the consequences of our own past creations they’re seeking to deliver us from. That report published last year celebrates the Army Corps’s recent “efforts to restore the natural characteristics of aquatic systems.” Those efforts include “hydrologic regime re-establishment, dam removal, river meandering, reconnecting floodplains, reintroduction of fire, etc.” More than 1,000 dams have been removed from American rivers in the past century, 72 of them last year. Homesteaders drained wetlands; after Hurricanes Katrina and Sandy, we’re building them. Battling the effects of climate change is now central to the Army Corps’s mission. Having spent centuries trying to bring natural forces under our control, our civil engineers are now declaring peace with them, or at least establishing diplomatic relations.
It’s enough to make you wonder if water might once again assume a place of prominence in our geographies, which is not to say that we should throw away our Global Positioning Systems and go back to using Joliet’s hand-drawn navigation chart. No matter how accurate or beautiful, all of those old maps leave out a crucial dimension, one that computer models of planetary processes have only recently added to ours: time. On our best maps, the rivers move. ------------------------------------- Donovan Hohn is the author of “Moby-Duck: The True Story of 28,800 Bath Toys Lost at Sea and of the Beachcombers, Oceanographers, Environmentalists, and Fools, Including the Author, Who Went in Search of Them.”