Winnetka explores stormwater tunnel
Updated: October 21, 2012 1:11PM
The Village Council’s ongoing look at flood relief plans includes a possible $34.6 million stormwater tunnel beneath Willow Road.
A proposed eight-foot diameter storm sewer would run under Willow Road from Glendale Avenue east toward Lake Michigan with new lateral stormwater systems feeding into it.
If approved, it would take up to 60 months to engineer and construct, and would use gravity to deposit rainwater from a large portion of the village into Lake Michigan.
According to Village Engineer Steve Saunders, the proposed project would provide potential flood relief for five of the eight drainage areas the council has previously looked at.
The council asked if the project was feasible considering all the permits, funding and potential construction issues to be encountered, but Saunders believes the project is doable.
The village would need permits or agreements with the state’s Environmental Protection Agency and Department of Natural Resources, the U.S. Army Corps of Engineers and Union Pacific Corp., as the tunnel would reside 18 feet below railroad tracks.
“They did spend quite a bit of time walking through the various regulations with us,” Saunders said, referring to the IEPA. “They gave us guidance on how to go through the permitting process, but they didn’t say we can’t do it. We didn’t get a stop sign which is good news.”
The project would cost an estimated $8-10 million less than trying to purchase more land to the west for water detention. The gravity system requires no pumping of water, which would not be possible if the water were directed west.
Though no official vote was taken during the council’s Sept. 11 study session, the trustees permitted Saunders to explore whether the underground tunnel could be constructed under Ash Street instead of Willow Road. Village staffers are curious whether moving the project one block north to Ash would result in significant savings and fewer construction headaches. ~.