March 16, 1937 -- Work Begins on the Chicago River Lock

March 16, 1937 -- Workmen begin driving 1,600 piles that will form a coffer dam a third of a mile east of the outer drive bridge. Ultimately 32,000 tons of concrete will rest on the piles, serving as support for the steel gates that will lie at the east west end of the lock intended to control the flow of water from Lake Michigan into the Chicago River. The work comes as a result of a 1930 U. S. Supreme Court decision that ordered installation of such a lock with a deadline of December 31, 1938. Today an estimated 50,000 vessels and 900,000 passengers go through the lock each year. It is one of two entrances to the Illinois Waterway system from the Great Lakes. The other is the Thomas J. O'Brien lock on the Calumet River.