Since 2006, the City of Chicago, has undertaken a massive, ongoing $60 million manhole rehabilitation project to address the City's aging system. In late July, 2010, four years following the beginning of the project, an unusually heavy rainfall dumped 7 in. in just a few hours. In early August, the already overburdened sewer system - which carries sanitary waste and stormwater through the same pipes - experienced another significant storm event.This time, infiltration and erosion undermined a major sewer line. Its subsequent failure led to a dramatic collapse of a section of sewer line on Mar-quette Avenue in Chicago's busy downtown. Portions of the street dropped 2 ft. Repairs took weeks and drew widespread attention to the aging, brick-and-mortar sewer system. But it also drew attention to the success of the ongoing repair project when the rehabilitated manhole in the section of collapsed sewer pipe remained structurally sound, significantly reducing the cost and time of the sewer repair.
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