 Work on the diameter crib began in 1915 and was completed May 1, 1918 after a delay to correct an out-of-plumb structure due to settling.The superstructure is rough-hewn granite block atop a steel caisson enclosing a diameter inner well chamber.Originally supplying eight miles of water tunnels, the crib has since been designated as a standby crib and is scheduled for demolition in the city's 2015-19 Capital Improvement Program.