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Willow Road STADI Project

Council Suspends Work on STADI Project- September, 2015

In 2014, after exploring a host of potential solutions to alleviate structural flooding even after major, 100-year storms, the Village hired an engineering firm to proceed with preliminary engineering and 30 percent design of a large diameter tunnel that would run beneath Willow Road and convey water from a roughly 900-acre drainage area on Winnetka’s west side eastward towards Lake Michigan.

The Village Council and staff worked closely with the engineering firm to evaluate project costs to determine whether the project was financially feasible.

In April 2015, the engineering firm provided cost estimates that were significantly higher than initial, conceptual estimates originally drafted in 2011-12. The Village then asked a separate engineering consultant to provide an independent cost evaluation of the increased estimate. That review resulted in an even higher cost estimate, putting the price tag for the Willow Road STADI project at approximately $81 million dollars.

Given that the tunnel project does not appear financially feasible at this stage, Village Council members decided to table this option in favor of taking a fresh look at non-tunneling options to address flooding issues in western and southwestern Winnetka. That process begins this fall and will include ample opportunities for residents to share their ideas about how to best deliver relief from structural flooding.


Willow Road Stormwater Tunnel and Area Drainage Improvements -- Review Point #2

On January 21, 2014, the Village awarded a contract to MWH Americas, Inc. to provide engineering services for the proposed Willow Road Stormwater Tunnel and Area Drainage Improvements (STADI) project. 

At the time the contract was awarded, the project was at a conceptual engineering stage—requiring MWH to undertake significant design and engineering to advance the project to a stage where permits could be submitted.  Importantly, the Council recognized the many complex steps and questions to be answered through the process, and therefore structured the contract with MWH to recognize decision, or “review points.”  The review points advance the project on a step-by-step basis without obligating the Village to the complete engineering services.

Review Point #1 occurred on June 24, 2014, when MWH submitted a Concept Review, Permit Plan, and Hydrologic/Hydraulic Model Verification.  Please see links below to access the agenda materials from Review Point #1:

At the conclusion of Review Point #1, MWH concluded the STADI project could achieve the Village’s desired flood reduction risks.  The Village Council authorized MWH to proceed with preliminary engineering and permitting tasks that were outlined in their original scope of work, and also authorized the implementation of a supplemental water quality sampling program.  Since last June, MWH has been focused on field investigations, water quality sampling, preliminary 30% design, and draft permit applications.

The Village Council will hold a special meeting on Tuesday, April 28, beginning at 7:00 p.m., at which MWH will present Review Point #2.  Due to the amount of size and materials, the Agenda documents are provided individually below.  Please keep in mind that some of these documents are still large files and may take time to download.

 Complete hard copy materials are also available for inspection at the following locations:

  • Winnetka Village Hall, 2nd Floor Administration (510 Green Bay Road)
  • Winnetka Public Works Yards (1390 Willow Road)
  • Winnetka-Northfield Public Library, Reference Desk (768 Oak Street)

April 28, 2015 Special Meeting Staff Agenda Report

MWH Materials Volume 1:

MWH Materials Volume 2:

April 28 Special Meeting Summary

MWH PowerPoint Presetation (PDF)

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