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


A Chief's report for the Upper Des Plaines River and Tributaries Feasibility Study was signed on June 8, 2015. This report was passed on to the Assistant Secretary of the Army (Civil Works) and Office of Management and Budget for approval, which was received on December 18, 2015. The final report was transmitted to Congress on January 29, 2016. Congress authorized construction in Section 1401 of WRDA/WIIN 2016. The $315M proposed project would have $10M in flood reduction benefits and restore over 6,800 acres of land.