Ellis Sylvester Chesbrough is one of Chicago's famous engineers. In 1855, the Chicago Board of Sewage Commissioners selected him to solve Chicago's public health crisis. He designed and oversaw construction of the nation's first comprehensive sewer system, allowing the city to continue to grow. His planned system relied on gravity flow, but downtown streets were too low to drain into the river. Large brick sewers were built above the existing ground level and then covered, raising the city's street level as much as ten feet. Sewage still flowed into the lake, however, in 1864, he began a two mile tunnel, sixty feet under the lake, out to a new intake crib. A crib takes water from the lake and goes to the pumping station to get purified. Today, Chicago gets its water from a series of "Cribs" initially designed by Chesbrough. This brought the city pure, clean water and was said to be an engineering wonder. Also, he is known for his successful river reversal in 1871 with the Illinois and Michigan Canal. He is important to Chicago because he created a system were the water gets clean so people could drink it. He also saved lives because people were getting very sick from the water and some were even dieing. He had a lot of impact on the city because we still use the Cribs he built to keep are water clean. His Cribs didn't really work, but now they do because we changed them a little so we wouldn't have had the problems he did.