Note: The Draft Feasibility Report and Appendices have been updated. For this reason, the public comment period has been extended to September 22, 2018.
AUTHORITY: Section 206, Flood Control Act of 1958
DESCRIPTION: The DuPage River and tributaries drain approximately 353 square miles in suburban Cook, DuPage and Will Counties in Metropolitan Chicago. The study area has experienced rapid development over the past several decades, and currently includes 40 communities affecting approximately 4,300,000 people. Major storm events occurred in the basin in 1996, 2008, 2009, and most recently in April 2013, resulting in significant overbank flooding in over 20 communities and significant damage to residential and non-residential structures and critical infrastructure and the closure of two major interstate highways (I-80 and I-55) for several days. Average annual flood damages are currently estimated at $30 million.
The DuPage River, Illinois Feasibility Study investigated overbank and backwater flooding along the DuPage River and its major tributaries, focusing on prioritizing high risk areas and developing a range of possible structural and non-structural alternatives to address flooding. A range of possible solutions were evaluated including floodwater storage, levees or floodwalls, diversion channels, channel modifications, flow control structures, flood-proofing, structure elevations and buyouts.
STUDY AREA: The DuPage River and tributaries drain approximately 353 square miles in suburban Cook, DuPage and Will Counties in Illinois. The study area has experienced rapid development over the past two decades, and currently includes 40 communities and approximately 900,000 residents. Major storm events resulting in overbank flooding in the basin occurred in 1996, 2008, 2009, and most recently in April 2013. The April 2013 flood impacted at least 20 communities and caused significant damage to residential and non-residential structures, critical infrastructure and the closure of two major interstate highways (I-80 and I-55) for several days.
Communities within DuPage County where flooding will be evaluated include, but are not limited to: Bartlett, Carol Stream, Glen Ellyn, Hanover Park, Lisle, Lombard, Naperville, Roselle, Warrenville, West Chicago, Westmont, Winfield and Woodridge. Communities within Will County include, but are not limited to: Bolingbrook, Joliet, Romeoville, Crest Hill, Plainfield, Minooka, Channahon, Plainfield Township, and Wheatland Township.
CURRENT STATUS: On July 31, 2018, the U.S. Army Corps of Engineers, Chicago District released for public review the “DuPage River Draft Detailed Project Report and Integrated Environmental Assessment.” The report is available for review under the “Study Documents” tab.
Two public meetings were held at 6 p.m. CST, Wednesday, Aug. 15, 2018, at the Auditorium of DuPage County’s JTK Administration Building, 421 N. County Farm Road, Wheaton, IL 60187; and 6 p.m. CST, Thursday, Aug. 16, 2018, at the Plainfield Public Works Building, 14400 Coil Plus Drive, Plainfield, IL 60544. The purpose of the meeting was to provide the public with information about the project, and seek input from members of the community and other stakeholders on the recommended plan.
The Army Corps of Engineers is accepting comments on the report from July 31, 2018, through Sept. 22, 2018. Comments may be submitted by e-mail to firstname.lastname@example.org or mailed to: U.S. Army Corps of Engineers, Chicago District, 231 S. LaSalle Street, Ste. 1500, Chicago, IL 60604, ATTN: DuPage River. Emailed comments must be received by Sept. 22, 2018, and mailed comments must be postmarked by Sept. 22, 2018.
HISTORY: On July 14, 2015, the U.S. Army Corps of Engineers, Chicago District, signed a Feasibility Cost Share Agreement (FCSA) with the DuPage County Stormwater Management Planning Committee and Will County Executive Office, which initiated the study.
During the initial phase of the study, the partners collected available data and developed preliminary alternatives to address the flood risks. This initial phase included public scoping as required by the National Environmental Policy Act (NEPA) and coordination with Federal, state, and local resource agencies. Once the scoping phase was completed, the Corps and the non-Federal sponsors began the process of developing computer models to simulate flooding and flood impacts in the watershed. The computer models use rainfall estimates, river capacity, and inventories of structures and infrastructure at risk to estimate potential impacts. These models allowed the study team to estimate the likely extent of flood risks and evaluate how effective proposed projects would be for managing those risks.
The study team also identified possible solutions to flood problems. The potential projects included levees, floodwalls, storage reservoirs, changes to bridges that obstruct the river, changes to the channel to increase its capacity, diversions to redirect floodwater around areas at risk of flooding, and non-structural measures such as buyouts and floodproofing. All of the information developed for the study has been coordinated with representatives of the communities at risk of flooding.
The quantity, frequency, and intensity of rainfall is a significant input to the computer models. An accurate estimate is important for capturing the likely extent of flooding. The rainfall estimates used in the State of Illinois for planning purposes are based on long-term rainfall records for the region, but haven’t been updated since 1989. Recently the Illinois State Water Survey conducted a review of rainfall trends in northeast Illinois and determined that the overall quantity of rainfall as well as the intensity of individual events is increasing. To support planning for the current conditions and future trends, the State of Illinois is updating the current rainfall estimates and developing future rainfall estimates.
The study team determined that this new data was be critical for estimating the current and future impacts of flooding in watershed communities. To allow for consideration of the increased rainfall trends in plan selection, the study schedule was extended to allow for inclusion of the State of Illinois updates.
PRESENTATIONS FROM INITIAL PUBLIC MEETINGS NOVEMBER 2015:
Public meetings were held Monday, November 16 in Bolingbrook, Ill., and Tuesday, November 17 in Wheaton, Ill., and Wednesday, November 18 in Shorewood, Ill.
Copies of the presentations from those meetings:
U.S. Army Corps of Engineers presentation about the DuPage River study
Presentation from DuPage County Stormwater Management
Presentation from Will County
NONFEDERAL SPONSORS: DuPage County and Will County