Hydrology of and Current Monitoring Issues for the Chicago Area Waterway System, Northeastern Illinois

Scientific Investigations Report 2015-5115
Prepared in cooperation with the U.S. Environmental Protection Agency– Great Lakes Restoration Initiative
By:  and 



The Chicago Area Waterway System (CAWS) consists of a combination of natural and manmade channels that form an interconnected navigable waterway of approximately 90-plus miles in the metropolitan Chicago area of northeastern Illinois. The CAWS serves the area as the primary drainage feature, a waterway transportation corridor, and recreational waterbody. The CAWS was constructed by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC). Completion of the Chicago Sanitary and Ship Canal (initial portion of the CAWS) in 1900 breached a low drainage divide and resulted in a diversion of water from the Lake Michigan Basin. A U.S. Supreme Court decree (Consent Decree 388 U.S. 426 [1967] Modified 449 U.S. 48 [1980]) limits the annual diversion from Lake Michigan. While the State of Illinois is responsible for the diversion, the MWRDGC regulates and maintains water level and water quality within the CAWS by using several waterway control structures. The operation and control of water levels in the CAWS results in a very complex hydraulic setting characterized by highly unsteady flows. The complexity leads to unique gaging requirements and monitoring issues. This report provides a general discussion of the complex hydraulic setting within the CAWS and quantifies this information with examples of data collected at a range of flow conditions from U.S. Geological Survey streamflow gaging stations and other locations within the CAWS. Monitoring to address longstanding issues of waterway operation, as well as current (2014) emerging issues such as wastewater disinfection and the threat from aquatic invasive species, is included in the discussion.

Suggested Citation

Duncker, J.J. and Johnson, K.K., 2015, Hydrology of and current monitoring issues for the Chicago Area Waterway System, northeastern Illinois: U.S. Geological Survey Scientific Investigations Report 2015–5115, 48 p., http://dx.doi. org/10.3133/sir20155115.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Chicago Area Hydrology
  • Current Monitoring Issues for the Chicago Area Waterway System
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Hydrology of and Current Monitoring Issues for the Chicago Area Waterway System, Northeastern Illinois
Series title Scientific Investigations Report
Series number 2015-5115
DOI 10.3133/sir20155115
Year Published 2015
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Illinois Water Science Center
Description vi, 48 p.
Country United States
State Illinois
City Chicago
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details