Construction will begin for a stormwater diversion tunnel that MWH was retained to design in order to alleviate the chronic, damaging flooding in the Albany Park neighborhood in the City of Chicago.
This $55 million rock tunnel is intended to move excess water from the North Branch of the Chicago River into the North Shore Channel, part of the Chicago Area Waterways System. The 18 foot finished diameter tunnel will be 5,700 feet long, going through bedrock approximately 140 feet below grade. The project is being completed by the City of Chicago Department of Transportation in partnership with the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC).
Flooding in the area occurs when excessive rains cause the flow in the Chicago River to overtop its banks. During the past 10 years, residents of the Albany Park neighborhood have had to deal with the aftermath of severe flooding on multiple occasions. The stormwater diversion tunnel concept developed and designed by MWH is intended to effectively reduce the risk of this hardship for events up to a 100-year design flood.
The new project’s flow diversion structure will capture more than half of the river’s design flood flow (2,300 cubic feet per second), and direct it into the tunnel via an inlet dropshaft. The flow will discharge downstream of the restrictive, flood prone reach of the river through an energy dissipation structure, and adjacent Chicago neighborhoods will be spared from the impacts of frequent overbank flooding.
- Geotechnical investigations and development of GBR (Geotechnical Baseline Report)
- Detailed geotechnical design of tunnel and shafts
- Comprehensive open-channel hydraulic modeling
- Structural design incorporating CFD (computational fluid dynamic) 3-D modeling for inlet and outlet structures
- Geotechnical support during construction
- Permitting and public outreach
- Urban Wet Weather Management and Flood Relief Project.
- Innovative plan to control overbank flooding relying on a passive system that relieves the North Branch of the Chicago River through an 18-foot bedrock tunnel directly under a busy urban corridor.
- Detailed Geotechnical investigations and tunnel design
- Complex hydraulic modeling and design
- Extensive permitting support
- Aggressive design schedule
“We have to find a solution. We got our engineers together and came up with a significant engineering feat that is actually quite elegant and simple in design,” said Transportation Commissioner Rebekah Scheinfeld. “We’ll be building a storm water diversion tunnel that will be over a mile in length. We’re [going to] go down 150 feet below the surface, tunnel through bedrock, then up on the south side of Foster over by the North Shore Channel where overflow water will then be bypassing the North Branch of the Chicago River.”
Read about Mayor of Chicago, Rahm Emanuel, endorsing the $55 million tunnel to relieve flooding in Albany Park, Chicago: Construction to begin on $55 million pipeline to relieve flooding in Albany Park.
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Albany Park Stormwater Diversion Tunnel Overall Plan
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