Wilson Avenue Crib Lighthouse

How did a lighthouse end up miles offshore in the middle of Lake Michigan? Here at the Wilson Avenue Crib Lighthouse, the answer isn’t about guiding ships but quenching the thirst of a growing metropolis. The Wilson Avenue Crib Lighthouse, completed in 1918, isn’t just a lighthouse. It’s a vital piece of Chicago’s history, a monument to engineering ingenuity, and a silent guardian of the city’s water supply. It stands as a testament to the lengths Chicago went to secure clean, fresh water. The Wilson Avenue Crib, as it’s also known, is one of several water intake cribs built to draw potable water from Lake Michigan. This ingenious system allowed Chicago to tap into the vast freshwater resource while avoiding the polluted Chicago River. Work on the Wilson Avenue Crib began in 1915. A massive steel caisson, ninety feet in diameter, was sunk into the lakebed. Then, square-hewn granite blocks formed the superstructure, housing the inner well chamber and the quarters for the city employees who staffed the plant and tended the light. The light, mounted atop a red circular tower, served as a navigational aid, warning boats away from the structure. A fascinating anecdote from the crib’s construction involves a settling caisson. Midway through the project, engineers discovered that the caisson had settled unevenly, causing the superstructure to lean. They ingeniously corrected this by boring holes beneath the low side and pumping in hydraulic cement, essentially jacking the structure back to level. Eight miles of tunnels, hand-dug through bedrock beneath Lake Michigan, connected the crib to the shore, a herculean feat of engineering and labor. These tunnels carried the precious lake water to the city’s pumping stations and subsequently to purification plants. The crib also housed a fog bell, which sounded regularly during periods of low visibility. For decades, crews of four to five men lived on the cribs, maintaining the equipment, tending the light, and ensuring the water flowed uninterrupted. Supplies and crew changes arrived via water department tugs, making the crib a self-contained community amidst the vastness of Lake Michigan. Today, the Wilson Avenue Crib Lighthouse, although designated as a standby crib, remains a striking landmark on the lake. It’s a reminder of Chicago’s innovative spirit and determination to provide for its citizens, a beacon of ingenuity in the heart of the Great Lakes.