Water Supply
The Lake Tunnel in Chicago
The Two-Mile Crib
In the mid-nineteenth century, Chicago was one of America's fastest growing cities. Lake Michigan provided a plentiful and easily accessible supply of fresh water. But the city dumped its sewage into the Chicago River, and since the river ran into the lake, the water supply near shore grew increasingly contaminated. Pipes that drew water from 150 feet offshore and even 600 feet out into the lake proved inadequate by the 1850s, when spring rains carrying pollution from Chicago's sewers, distilleries, and slaughterhouses contaminated the water supply.
Ellis S. Chesbrough solved the problem in 1863 by designing a tunnel under the lake that would bring fresh water from two miles offshore. The tunnel was to be 5 feet wide and lined with brick, and would extend through the clay bed of Lake Michigan to a distance of 10,567 feet. Work started in 1864, and was far enough along by 1867 that this pamphlet could give a detailed description of the progress. A notable feature of the plan was the Two-Mile Crib, a mammoth timber intake structure launched in 1865 and placed in clean, deep waters on top of the lake-end of the tunnel. It is shown here in cross section, along with the tunnel under the lake.
Digging the Lake Tunnel
The two-mile tunnel under Lake Michigan proposed by Ellis Chesbrough in 1863 brought him international fame when it was completed and, with its remarkable Two-mile Crib intake structure, was heralded as the eighth wonder of the world. Tunnel construction began in May 1864 and then continued for 24 hours a day and six days a week. A lower semicircular arch was dug and built about six feet in advance of the upper arch. Two men could work side by side, with the miners in front and the masons laying brick about 10-20 feet behind.
Two small mules were found to work in the tunnel, pulling railroad cars to move clay out and building materials in. Digging proceeded first from the shore end and later from the lake end of the tunnel. Chesbrough and a few other dignitaries descended into the tunnel to remove the final inches separating the two tunnels in November 1866. The mayor placed the final masonry stone, and fresh water from the lake entered the tunnel for the first time with great fanfare in March 1867, bringing pure unpolluted water into the city through the structure.
Chicago Water Tower
The success of the water supply system designed by Ellis Chesbrough for Chicago made it a model for other cities that border large bodies of fresh water, as well as a precedent for expansion of Chicago's system. By 1905 when the City Engineer wrote this report and gave this copy to the ASCE, Chicago had five cribs for taking water from the lake and used multiple pumping stations.
The Chicago Water Tower and pumping station is a familiar landmark at North Michigan and Chicago avenues that was completed in 1869 as part the plan for the water supply system. The tower housed a vertical standpipe 138 feet tall that relieved excess pressure in the distribution lines. Designed in a Gothic style by architect William Boylington and built of stone, it was one of a few buildings to survive the great Chicago fire of 1871, and remains today as a symbol of one of the remarkably successful civil engineering projects of the nineteenth century.