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Driving down 127th Street, you might not notice the hill Blue Island sits on–even though it’s about 50 feet high, a mile wide, and six miles long north to south. According to A.T. Andreas’s 1884 History of Cook County, Blue Island got its name because weary voyageurs sick to death of flat, swampy prairie sometimes had the illusion that its heavily wooded north end was floating on a distant, shimmering lake.

At its southern end the ridge met the sluggish Little Calumet River, spawning first a speculators’ paper city, “Portland,” and then a real one. Those who know Blue Island today think of it as an old railroad town down on its luck, like Galesburg or Burlington. But Blue Island was a canal town before the Rock Island line ever arrived. The “Calumet feeder” between the Little Calumet and the old Illinois and Michigan Canal was dug between 1846 and 1848, and first filled with water June 12, 1849. This wasn’t the last time people tried to improve the waterways around Blue Island. The latest attempt–a scenic pollution-control device invented by Mother Nature and reinvented by the Metropolitan Water Reclamation District–was dedicated, coincidentally, on June 12, 1992.

As the metropolitan area grew in the late 1800s, the eerie flatness that had once been psychologically oppressive became menacing–the rivers never had enough current to carry away everyone’s sewage. In 1889 the state legislature finally authorized the creation of the Sanitary District of Chicago, which would send the region’s sewage downstate via a “sanitary and ship canal,” well diluted with clean lake water.

Most of us have heard of the pioneering ten-year task of reversing the Chicago River that followed: digging the canal, at times through solid rock, and surreptitiously opening the gates one day before Saint Louis could file suit against the project. Popular history ends there, but the district kept on. Besides the Sanitary and Ship Canal, it also dug the North Shore Channel (connecting the North Branch of the Chicago River to the lake near the Baha’i temple in Wilmette) and the Calumet Sag Channel, which runs roughly from Argonne National Laboratory to just east of Lake Calumet.

By 1911, when the district began digging the Cal Sag, its engineers were aware of other ways to deal with sewage. But they knew best how to dilute it and flush it downstream, and besides, another canal would help create a barge highway running from the Illinois River to Calumet Harbor on Lake Michigan. Finished in 1922, the channel sent sewage away from the lake, and also gave cargo en route from the Mississippi to the Great Lakes a way to bypass the Loop.

As the century wore on, the Sanitary District–enlarged and renamed the Metropolitan Sanitary District of Greater Chicago–went beyond the dilution solution and built sewage-treatment plants, collecting the outflow from millions of toilets and making it less noxious. After being allowed to sit around and settle out, and then being aerated and digested by microbes, the wastewater went back into the district’s waterways, where natural processes would supposedly finish the job. They did, but in the early days the water had to flow most of the way to Peoria before the natural processes were finished. The name Sanitary and Ship Canal was a misnomer for those downriver, and the water in the Cal Sag Channel was, if possible, worse. Even carp couldn’t live in it.

Sewage doesn’t just smell bad. The microbes that reduce it to a relatively benign state consume oxygen–just like fish, clams, and protozoa. But water can dissolve only a limited amount of oxygen. At 70 degrees under ideal conditions, it can hold about eight parts of oxygen per million parts of water. At 90, it can hold only seven. The more sewage there is, the less of that oxygen is available to things like fish. And, most relevant to northeastern Illinois, the flatter the channel, the less its natural flow will be able to stir up the water, aerating it naturally. The waterway of which the Cal Sag is a part is almost as flat as a lake–it falls only eight feet in the 40 miles from Lake Michigan to Lockport.

The water got cleaner as sewage-treatment technology improved and as the district’s Deep Tunnel came into operation. (Deep Tunnel enables the district to store excess sewer water for future treatment, rather than let it bypass overloaded treatment plants and dump straight into the waterways.) The district figures that the water coming out of its treatment plants is 95 percent cleaner than what came in. But even so, the Cal Sag couldn’t meet the standard the state set for it: at least three parts oxygen per million parts water.

The district’s engineers expected to have to filter the remaining gunk out using elaborate and expensive “advanced treatment” systems. (The last few percent are always the most expensive.) Then, about ten years ago, the Sanitary District began getting double-barreled bad news from the EPA. The new filtration systems cost too much and accomplished too little, so the feds decided not to finance them. But they still expected the district to upgrade its artificial waterways. Somehow.

If necessity was the mother of invention, then perhaps district engineer Bill Macaitis was its midwife. He knew the reason for filtering was simply to keep those last few solids from consuming scarce dissolved oxygen. Why not leave the solids in and simply dissolve more oxygen in the channels? Sometime in 1983 he sketched a deceptively simple way of doing that: raise the water with a pump and then drop it back through the air. In other words: build a waterfall.

On June 12, 143 years to the day after Blue Island got its first canal, the town got its first waterfall–on the north side of the channel, at the foot of the Blue Island hill, just east of the Metra station and the Western Avenue bridge. Because this is the 20th century, it is officially known as a Sidestream Elevated Pool Aeration Station (and the district is now known as the Metropolitan Water Reclamation District). The dedication ceremony had hot sun, a school band, and a priest who likened the Cal Sag Channel to the River Jordan. Missing was the state EPA, which had approved the design and come up with three-quarters of the $39 million cost.

What makes it a waterfall and not just a SEPAS is its parklike eight-and-a-half-acre setting. The pump house contains four huge screw pumps, each ten feet in diameter, that are big enough to lift 40 percent of the Cal Sag’s flow 15 feet to the top of the waterfall. Its limestone walls, steep roof, and turn-of-the-century wooden arbor in front make the pump house look so much like a church that during construction some locals asked to reserve it for a wedding.

From the pump house a slightly sunken path, reminiscent of the old Illinois and Michigan Canal with its waist-high walls of tawny limestone blocks, leads to the waterfall itself–an amphitheater that faces the channel. Visitors stand along the top looking over a railing as the dark green water surges out beneath the walkway, down over three half-circle cascades, and back into the channel.

According to district plans, the Blue Island waterfall and four companions should each roughly double the dissolved-oxygen content in the channel. Upstream are two Chicago stations, at 127th Street and at Torrence Avenue, both under construction. Below Blue Island are the Worth station, which was dedicated June 26, and the Canal Junction station, which is under construction near 107th and Route 83. At the June 12 ceremony, which was attended by officials from Wisconsin and Minnesota considering similar projects, the trout-loving Macaitis went out on a limb and predicted that the Cal Sag would soon contain “bass, pickerel, and, I hope, a couple of steelhead.”

Macaitis, accustomed to working on the often-controversial Deep Tunnel, is pleased that no one opposed his creation. The five waterfalls-cum-parks were some $270 million cheaper than advanced filtration would have been, though he is quick to point out that without good sewage-treatment plants and the Deep Tunnel, an urban waterfall wouldn’t help much: it would probably foam and stink. “When it’s 95 percent clean already, then you can do something like this. This is the last little kick that gets us there.”

The worst you can say about urban waterfalls is that they don’t address tougher kinds of pollution, like toxic chemicals. But anyone who has wrestled with an overflowing toilet will appreciate the difficulties of coping with sewage. And the idea of engineers mimicking nature–even when alleviating human-made pollution of a human-made waterway–is nice to hang on to. After all, how many other sewage-treatment officials can say people have asked to get married at their facility?

Art accompanying story in printed newspaper (not available in this archive): photo/John Sundlof.