When Chicago was incorporated as a town in 1833, it had a population of just 350, and the town’s inhabitants used the Chicago River as the source of its drinking water. Over the next seven years, the population swelled more than tenfold, and the river had become contaminated.

1866 Two Mile Crib

In 1842, local businessmen formed the Chicago City Hydraulic Company, which tapped the seemingly endless supply of fresh water available in Lake Michigan. A wooden intake pipe was run roughly 150 feet offshore, and a steam-powered pump was used to draw water into an elevated wooden tank from which it was fed to a network of wooden water pipes. The City of Chicago purchased the Hydraulic Company in 1852, and over the next decade, the water system had grown to include three half-million-gallon wrought iron reservoirs and over ninety-five miles of cast iron distribution pipes.

By 1860, the city’s population had burgeoned to over 100,000, and the Chicago River had become a veritable cesspool as raw sewage and waste from the numerous slaughter houses and other industries flowed freely into it. With a significant number of its citizens dying from cholera and typhoid fever, the city hired Ellis Chesbrough in 1861 to serve as the Chief Engineer of the newly formed Board of Sewage Commissioners and tasked him with improving the city’s water supply and sanitary systems.

Chesbrough’s plan called for the excavation of a supply tunnel to connect a pumping station situated five miles inland to an intake crib located two miles out into Lake Michigan, well beyond the increasingly polluted shoreline. Dull & Gowan of Harrisburg, Pennsylvania signed a contract for the massive project on October 28, 1863, and work got underway the following May.

A wooden, double-walled crib, pentagonal in shape and with a height of forty feet, was built on shore and then towed into the lake by steam tugs and sunk in position by filling its hollow walls with stone. A cast-iron caisson was lowered inside the intake crib, appropriately named Two Mile Crib, and then driven into the lake floor. After the water was evacuated from the caisson, workers entered and excavated a vertical shaft to the prescribed depth before tunneling horizontally to meet the passageway being extended from shore.

Centered atop the crib was a rectangular building that contained a kitchen and bedrooms for the crib keepers along with storage space. Above this structure was a square tower that supported a birdcage lantern for displaying a light to warn mariners away from the manmade navigational hazard. The crib was also equipped with a fog bell that was struck once every minute during periods of poor visibility. Keepers lived on the crib year-round to tend the light and fog bell, and to operate the intake doors in the crib and keep ice from forming inside the crib.

Two Mile Crib in 1910 Photograph courtesy Library of Congress

The tunnel was completed on November 30, 1866, and the water system commenced operation the following year. Although the City of Chicago was responsible for maintaining the light and fog bell on the crib, these navigational aids did appear on the Lighthouse Service’s official List of Lights. In 1877, the Lighthouse Board noted that a proper light should “be placed upon the crib at the outer end of the tunnel of the Chicago water-works, to replace the present inefficient one, not under the control of the Light-house Establishment.” Four years later, the Board noted that they had reached an agreement with the City of Chicago to furnish the crib “with a third-order lens, lamps, &c, and set them in working order when the city builds the tower and lantern.”

As the population of Chicago continued to grow, additional cribs were built offshore. In 1898, the existing eight water intake cribs were capable of supplying the city with nearly a billion gallons of water each day. The cribs that exist today are Four Mile Crib (1891), 68th Street Crib (1892), Carter H. Harrison (1900), Edward F. Dunne Crib (1909), Wilson Avenue Crib (1918), and William E. Dever Crib (1935). The final crew of keepers was withdrawn from duty in 1990.

To thwart terrorist activity, security systems were installed on all the intake cribs in 2002. These systems include motion detectors, video cameras, and door sensors, and are linked to the Chicago Police through a microwave link. Vessels are prohibited from entering a buoyed zone around each crib.

Wilson Avenue Crib

Work on this circular crib, located roughly three miles offshore from the eastern end of the avenue for which it was named, began in 1915 with the sinking of a steel caisson having a diameter of ninety feet. Built using square-hewn granite blocks, the superstructure protects the inner well chamber that has a diameter of forty feet. An eight-mile-long tunnel connected the crib with the onshore pumping station.

On October 23, 1915, Wilson Avenue Intake Crib Light was established to mark the new crib during its construction. The fixed white light was suspended from a wooden post on a timber platform and had a focal plane of thirty-five feet. A fog bell was also installed to sound a single stroke every fifteen seconds.

When the crib was nearing completion, it was discovered that the superstructure was eighteen inches out of plumb. The concrete joining the superstructure to the steel caisson was blasted away, and three hundred jacks were used to level the superstructure. This delicate work delayed the completion of the crib until May 1, 1918.

A red circular tower topped by a lantern room was mounted atop the center of the crib’s roof to serve as a permanent navigational aid. This tower initially exhibited an acetylene light that was visible for up to eight miles. A fog bell, struck a double blow every twenty seconds, was used during low visibility.

References

1. “The Engineering Marvel of Chicago’s Water Intake Cribs,” Terry Pepper, The Beacon, Winter, 2009.
2. Annual Report of the Light-House Board.
3. Report of the Commissioner of Lighthouses.

Wilson Avenue Crib Light is best seen by boat or plane.

The lighthouse is owned by the Chicago Department of Water Management. Tower closed.

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