US Army Corps of Engineers
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Des Plaines River - Phase II


Water Resources Development Act 1999, Section 419


The Des Plaines River flows from southeast Wisconsin to northeast Illinois. It is 67 miles long, flowing through 33 municipalities. There is frequent flooding. In 1986, the flood of record occurred and affected 15,000 residents, their dwellings and businesses, as well as the area’s transportation network. This study expands the area of concern from the mainstem in Illinois to include the entire Upper Des Plaines watershed, comprised of 15 tributaries in Illinois and Wisconsin. In addition to flood risk management, the purpose of this study also includes ecosystem restoration, water quality and recreation features. There are over 43 municipalities in the watershed that contend with flood damages from the Des Plaines River and its tributaries. 

Recent flood events include a new flood of record in April 2013, along with previous events that occurred in May 2004, August 2007, September 2008, and December 2008, each of which resulted in significant flood damages and disaster declarations. The Phase II study had three primary objectives: further reduction of main stem flooding; reduction of tributary flooding; and environmental restoration of degraded ecosystems within the basin. The study considered sites located within tributary watersheds and along the main stem for both Flood Risk Management (FRM) and Ecosystem Restoration potential. The effects of FRM sites within tributary watersheds on main stem flooding were also evaluated.

The Upper Des Plaines River and Tributaries, IL & WI Integrated Feasibility Report and Environmental Assessment was released Sept. 3, 2013, for public comment and a Documentation of Changes was released for public comment Jan. 17, 2014.

The plans recommended by the study report propose the construction of levees, reservoirs and other features to reduce flood damages in the Upper Des Plaines River watershed. If approved, the projects will reduce flood risk in communities across the watershed, providing approximately $6.8 million annual net economic benefits.


Total Project Cost:

  $ 12,944,000

Federal Cost:

  $ 6,713,000

Non-Federal Cost:

  $ 6,231,000


This project was authorized for construction in Section 1401 WRDA(WIIN) 2016.  It authorized the construction of a system of 3 levees and 2 reservoirs along with over 300 non-structural sites throughout Cook and Lake County for flood risk management.  In addition, 7 ecological restoraion sites in Cook, Lake and Kenosha County were authorized for construction.  The total authorized cost is $315,502,000.