|Four Mile Crib, IL|
Description: 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.
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.
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.
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.”
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.
Four Mile Crib
This crib, the second built to supply water for Chicago, was built farther out in the lake to avoid contaminants fed into Lake Michigan by the Chicago River. Completed in 1891, the stone and brick crib alone cost $472,890.93, but the total cost of the system, which included two six-foot-diameter tunnels connected to pumping stations at Park arrow and Indiana Avenue, came to $1,526,143.68.
Located just over three miles offshore from Meigs Field and Navy Pier in Chicago. The lighthouse is owned by the Chicago Department of Water Management. Tower closed.
The lighthouse is owned by the Chicago Department of Water Management. Tower closed.
Pictures on this page copyright Kraig Anderson, used by permission.