Lee Sandlin was born in Wildwood, Illinois, grew up in the suburbs of Chicago, and currently lives in Chicago proper. He’s written feature journalism, historical studies, and opera and classical-music reviews—mostly for the Reader, where he has also covered TV. Wicked River is his second book.

There is a tributary of the Mississippi River running through my neighborhood in Chicago. It’s not easy to spot; you have to know just where to look. It’s by the bus stop on a cluttered commercial block. Right at the curb is a manhole. The manhole cover is embossed with a decorative pattern of fish, and it carries the message dump no waste! drains to waterways! Down below is water bound for the Mississippi.

Sometimes when I’m waiting for the bus, I pass the time by imagining the course the water is running. It’s invisible at street level, but there is a maze of piping underneath Chicago: water mains and sewer mains and gas mains, electrical conduit and fiber-optic cabling. The water is gurgling through this spaghetti tangle for mile after mile, below the ranges of high rises and the decaying industrial districts and the limitless veldts of bungalows. It doesn’t surface until it reaches a pumping station past the southern city limits. There it empties into the Illinois River. The Illinois runs in a meandering course roughly southwest, past the suburban counties around Chicago, out through the exurban fringe, then south through the farm country in the middle of the state, and then west again, until at last, just north of Saint Louis, it drains into the Mississippi.

This is a serpentine route, but it’s not an unusual one. There are countless streams just like it. In the 19th century, it was estimated that the Mississippi had roughly one hundred thousand natural tributaries—that is, there were a hundred thousand distinct, individually named brooks, creeks, rivulets, and rivers emptying their waters into its gargantuan current. Today there are far more than a hundred thousand, and the majority of them are artificial. They’re like the manhole by the bus stop: they’re conduits and cisterns and sewage pipes, obscure canals and neglected culverts and out-of-the-way storm drains. The Mississippi is surrounded by a vast network of concealed plumbing that underlies the whole of the American midwest.

As for the great river at the heart of this maze, it is now for all intents and purposes a man-made artifact. Every inch of its course from its headwaters to its delta is regulated by synthetic means—by locks and dams and artificial lakes, revetments and spillways and control structures, chevrons and wing dams and bendway weirs. The resulting edifice can barely be called a river at all, in any traditional sense. The Mississippi has been dredged, and walled in, and reshaped, and fixed; it has been turned into a gigantic navigation canal, or the world’s largest industrial sewer. It hasn’t run wild as a river does in nature for more than a hundred years.

Its waters are notoriously foul. In the 19th century, the Mississippi was well known for its murkiness and filth, but today it swirls with all the effluvia of the modern age. There’s the storm runoff, thick with the glistening sheen of automotive waste. The drainage from the enormous mechanized farms of the heartland, and from millions of suburban lawns, is rich with pesticides and fertilizers like atrazine, alachlor, cyanazine, and metolachlor. A ceaseless drizzle comes from the chemical plants along the riverbanks that manufacture polychloroprene and other performance elastomers, as well as refrigerants. And then there are the waste products of steel mills, of sulfuric acid regeneration facilities, and of the refineries that produce gasoline, fuel oil, asphalt, propane, propylene, isobutane, kerosene, and coke. The Mississippi is one of the busiest industrial corridors in the world.

I get a little reminder of the health of this system every time I pass by that bus stop. There’s a reason why the one particular manhole stands out among all the clutter of ancient grilles and grates along the block. It reeks. Winter and summer, it emits a peculiar odor, a compound of sewer gas, stale grease, and some kind of pungent chemical reminiscent of sour mint. I can tell how bad it is on any given day by the behavior of the people waiting at the curb. Sometimes they have to hang so far back that the bus blows past the corner without a pause.

Of course it seems all wrong to think of the Mississippi River this way, as an industrial drainage system the length of a continent. It’s not how we want to picture Old Man River—the river of the paddle-wheel steamboats, the river that Huck and Jim escaped down when they rode their raft to freedom. That river, we like to imagine, is still running wild the way it always was. The wistful old song “Moon River,” popular back in the 60s, caught the feeling perfectly:

Moon River, wider than a mile,

I’m crossing you in style some day.

When Andy Williams crooned this, he was obviously not thinking about something as prosaic as driving across the Eads Bridge at Saint Louis. He was singing about the mythical river of Mark Twain (“my huckleberry friend,” the song calls it, just so we don’t miss the point): he was crossing a river bound for the rainbow’s end, not one to be found on the interstate map.

This is the image of the river that I grew up with. I knew all about Twain’s river long before I ever saw the actual Mississippi. In fact, I knew about Tom Sawyer and Huckleberry Finn before I learned how to read. My mother had an old illustrated edition of Twain, and sometimes when I was a little kid, she would take it down from its high shelf to show me the pictures. The book was filled with glossy plates, each protected by a thin sheet of brittle tissue, which she would delicately peel back to reveal the gorgeously colored image underneath. It never failed to astonish me. I was used to modern picture books, where pop art squiggles were at play in a featureless smear of watercolors, like a cartoon guide to subatomic physics. But here with dream-vivid clarity was Tom Sawyer in church, squirming through the sermon between two pillowy matrons in spectacular floral dresses; there was Huckleberry Finn in overalls, sitting on a barrel on the levee, smoking his corncob pipe, posed against the steepled skyline of Hannibal, Missouri, with a sun-rayed billow of cumulus behind. . . .

There was nothing remotely like it in the Illinois suburb where I grew up. The one river I knew was a dinky, puttering brook that meandered through a nearby forest preserve. It was opaque, it smelled putrid, and its surface was fluorescent green. We were told to stay out of it, because if its water even touched our skin, we’d have to go to the hospital.

Twain’s Mississippi was obviously something different, something wholly other. I was haunted by the thought that it was close by, running deep within the landscape, past the last franchise strip and the last strand of freeway. Sometimes I imagined it as a kind of secret subterranean presence flowing around the walls of basement rec rooms. On the maps in my schoolbooks it seemed to cut through the whole of the midwest like the dark central vein in a leaf: I thought that if I ever managed to reach it, I would be swallowed up in a kind of hidden inland sea, endlessly unfolding from within, dotted everywhere by the glorious islands of the steamboats, edged by the silhouettes of forests against a sunset sky.

That image was so alive to me that it easily survived my real-world encounters with the river. My parents would sometimes take me on trips to visit my great-aunts and great-uncles, who lived on the Illinois side of the Mississippi near Saint Louis. The drive led us from the Chicago suburbs down the new interstate—a summer morning’s glide through the furrowed green oceans of the farm country, our car and the cars all around us swooping effortlessly along the arrow of highway like an invading army of flying saucers. My gaze was invariably fixed on the horizon, where the grain silos and water towers were creeping past each other like pieces in a titanic board game. I remember a thunderstorm rising up above the horizon line, one of those towering prairie storm fronts that to this day make me think of God long before I think of rain. We were heading straight into it. The highway stretched before us in a brilliant swath of humid yellow sunlight, while ahead was a wall of blackness. We swept into the storm in a furious rush; the car didn’t slow at all, even though the windshield wipers were frantically shoving the surging sheaths of rainwater aside as though they were combing the sea. On the far side of the storm front, the world was a sulking monochrome. Off the interstate we headed down a main highway hemmed in by franchise strips, discount furniture stores, and new-car lots; the rain was descending in thin curtains over sodden hills of subdivisions. The road took a bend, and there was the Mississippi.

It was gray. It was hurrying. It was huge. Its surface was mottled and stippled with countless flickering motes of black, like the seethe of snow on a TV screen. It had nothing to do with the river I had imagined. It didn’t even seem to be a natural phenomenon. It was an interruption in the landscape, a flood, a mob trampling through a barricade, an endless, purposeless stampede of water. A half a mile off in the deep channel was a gigantic industrial barge shrouded by rain. On the remoteness of the far bank, more than a mile away, was a line of gaunt dead trees.