From the Trib article (http://www.chicagotribune.com/news/local/breaking/chi-chicago-river...):

Beginning this weekend, the city will be raising bridges across the Chicago River to allow sailboats to migrate from Lake Michigan.

Bridges across the main and south branches of the river will be raised on Wednesdays and Saturdays to allow the boats to head to storage yards for the winter.

Each of the city's 27 movable bridges will be raised for about 8 to 12 minutes, according to the city's Department of Transportation.

Bridge lifts start at Lake Shore Drive at about 9 a.m. on Saturday, starting at the same time each Saturday until Nov. 10. The lifts will start at 9:30 a.m. next Wednesday and each Wednesday until Nov. 14.