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Stormwater Review

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In July 2011, Winnetka was impacted by a significant rainfall that overwhelmed the Village’s sewer systems and led to severe flash flooding and basement flooding throughout the Village. A Cook County Precipitation Network rain gauge located in southwestern Winnetka, recorded a total of 6.61 inches by the end of the storm event.

With the exception of a narrow strip along and west of Green Bay Road, Winnetka is what is known as a “separate-sewer” community—meaning that there are two separate sewer systems. The storm sewer system collects stormwater runoff from streets and yards, downspouts, and sump pump discharges, while the sanitary sewer system collects wastewater from interior plumbing systems. The Village’s storm sewers drain either to the Skokie River and its tributary, the East Diversion Ditch, or to Lake Michigan. Although the two watersheds are generally divided by the Union Pacific Railroad tracks, an area around North Shore Country Day School does drain east under the railroad towards Lake Michigan. The Village’s sanitary sewers drain to a network of intercepting sewers operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRD). These intercepting sewers convey wastewater to the North Side Treatment Plant located near Howard Street and McCormick Boulevard in Skokie, where it is treated and discharged to the North Shore Channel, and ultimately, to the North Branch of the Chicago River.

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In 2009, Christopher B. Burke Engineering, Ltd. (CBBEL) was hired by the Village to conduct a Flood Risk Reduction Assessment of the western Winnetka study area, in response to widespread flooding in September 2008. Also in 2009 and just before the July 2011 event, CBBEL had designed 10-year level flood protection projects for eight areas that flooded significantly during heavy rains. Immediately following the July 2011 storms, the CBBEL study was expanded to analyze 25-, 50-, and 100-year design storm events and to recommend alternatives to reduce the risk of future flooding. Ultimately, the Village has adopted a Stormwater Management Program that outlines $41.4 million in stormwater infrastructure improvements, which it is anticipated will significantly reduce structural flooding in Winnetka by 2017.

Monthly Stormwater Reports

On a monthly basis, the Village’s Stormwater Project Manager, provides a report to the Winnetka Village Council—updating them on the status of key projects, schedule of stormwater-related meetings, and project budget to-date. These reports are useful resources in understanding the numerous, interrelated projects that currently make-up the Village’s plan for stormwater improvements and can be found on the Documents & Forms page.

Stormwater Questions and Comments

Winnetka’s Village Council and staff welcome resident input regarding stormwater mitigation efforts. All residents are encouraged to share thoughts and suggestions by submitting them to: Stormwatercomments@winnetka.org.

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