Winnetka Village Council hires firm for storm master plan
Updated: July 2, 2012 12:18PM
Flash flooding last July overwhelmed Winnetka’s stormwater drains and sewers, causing water to rise up front yards ,and in some cases, burst through window wells.
All five Winnetka District 36 schools experienced flooding, as did New Trier Township High School and the Winnetka Public Library.
So members of the Winnetka Village Council are eager to get going on a Stormwater Master Plan that will provide a framework for managing stormwater detention and drainage throughout the village.
On Tuesday, the council in a 7-0 vote awarded a contract to Baxter and Woodman to prepare a master plan, which also will examine areas left out of earlier studies and look at financing options. Town Meetings will be held to elicit residents’ input and educate homeowners.
The consultant’s costs have been capped at $101,220.
The flash flooding of July 2011 marked the third extreme rain event in the past several years, and a flood control study already was underway at that time. A 2009 study of one area of west Winnetka by Christopher B. Burke Engineering showed the stormwater infrastructure had less capacity than was needed to handle a five-year storm, that is, one with a 20 percent chance of occurring in a single year. The firm was then retained to look at six additional areas and found the other sections of the village also had less than a five-year capacity; some could not handle a two-year storm, or one with a 50 percent chance of occurring each year.
Following the July 2011 flood, when seven inches of rain fell on the Winnetka-Northfield area, the village expanded the firm’s work to cover more more extreme storms that occur every 25, 50 and 100 years.
The village has begun work on some of the recommended improvements, but full financing of projects estimated to cost $39 million has yet to be determined. If the improvements are financed through general obligation bonds repaid with property taxes, a $40 million bond issue would cost, on average, an additional $658 a year per parcel over each of the next 20 years, according to a village analysis last fall. The village also plans to conduct a stormwater utility rate study that will look at financing improvements through higher charges for water and sewer service.