Winnetka Considers a $34.6 Million Stormwater Tunnel

Winnetka trustees could consider installing new storm sewers beneath Willow Road to ease the village’s flooding issues after hearing a presentation by the village engineer Tuesday. 

The proposed Willow Road Tunnel project would install an eight-foot diameter storm sewer underneath Willow Road from Glendale Avenue to Lake Michigan that would use gravity to move water from a roughly 900-acre drainage area in west Winnetka eastward toward Lake Michigan. 

“The various hurdles that I could imagine and (the engineering firm) could imagine would stop this projects in its track don’t seem to be an issue in terms of the ultimate piece of the project,” said Village Engineer Steve Saunders. 

Winnetka contracted engineering firm Christopher B. Burke Engineering to present a feasibility report for the proposed Willow Road Tunnel project. The Rosemont-based firm has worked with the village on past storm sewer-related projects. 

Provide Flood Relief to Five Areas

The proposed Willow Road Tunnel project is estimated to cost about $34.6 million and would include new lateral stormwater systems feeding into it. The project could be executed in conjunction with the village’s  between Forestway Drive and Provident Avenue.

Saunders told trustees that the proposal could provide flood relief to five drainage areas; north and south of Willow Road, Provident Avenue area, Cherry Street Outlet and the underpass area near . 

The proposed tunnel could also eliminate the need for stormwater storage on or Cook County Forest Preserve District properties. 

“This project is significantly less expensive than the estimated cost to provide the same level of protection if we were to go west and use the distributed detention approach, about $7 million in savings with the tunnel method and it doesn’t require all the intergovernmental land acquisitions,” Saunders said.

Village Seeks Other Cost-Saving Opportunities 

Village trustees did not officially vote to approve the project but directed Saunders to explore whether there are other cost-savings by relocating a portion of the tunnel one block north to Ash Street. Village documents shows that moving a section of the tunnel could eliminate some of the necessary connecting pipe runs and allow a different tunneling method.

If the Village Council approves the project, it could take between 60 to 66 months to negotiate the required permits, engineer and construct, Saunders said.

In order to start the project, Winnetka would need permits or agreements with Illinois Environmental Protection Agency, the U.S. Army Corp of Engineers, Illinois Department of Natural Resources and Union Pacific Corporation, since the proposed tunnel route crosses under the Union Pacific Railroad at Willow Road.

“The IEPA was the most difficult to pin down,” Saunders said. “They gave us guidance on the permitting process and the one thing they didn’t tell us, was that we couldn’t do it ....They didn’t give us the stop sign, which is good news.”

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