Abstract
In the past decade, continuously rising water levels in Lake Michigan have been threatening lakefront areas, especially in metropolitan regions like the Greater Chicago area. This provides the motivation to analyze the
impact that high lake levels have on the Chicago Area Waterway System (CAWS). As the only primary free connection between the CAWS and Lake Michigan, the Calumet Area waterway subsystem plays a key and unique role. In this work, a numerical model covering the Calumet subsystem and having Lake Michigan as a boundary condition, is set up, calibrated, and validated using limited field observations. It is found that the Calumet subsystem has become bidirectional, where both discharge and flow directions are controlled by lake levels. When lake levels are below -0.15 m (-0.5 ft, Chicago City Datum, CCD), the discharge in the Grand Calumet River is around zero, with water flowing along its east branch towards Indiana. When lake levels are above +0.46 m (+1.5 ft, CCD), the flow reverses direction and drains west into Illinois. In 2020, the mean lake-level was at +1.07 m (+3.5 ft, CCD), and the base discharge in the Grand Calumet River was approximately 8.5 m3 /s (300 ft3/s). The higher Lake Michigan’s level is, the larger the discharge would be into Illinois. Potential impact of this extra discharge on Lake Michigan Diversion Accounting (LMDA) of the State of Illinois and flood management in the Chicago Sanitary and Ship Canal (CSSC), is analyzed; while the nature of the bidirectional flows is characterized with the intent of shedding light on this complex phenomenon.
Bio
Dongchen Wang is a Ph.D. candidate in the department of Civil and Environmental Engineering at University of Illinois. Under the supervision of Prof. Marcelo H. Garc´ıa, his research topic focuses on understanding the
density effects in the mixing process in the environmental flows via numerical models, field measured data and remote sensing data. Prior to this, he worked two years at National Laboratory for Hydraulics and Environment
(LNHE) near Paris on the development of Navier-Stokes and Shallow Water equations coupled with Exner equation High Performance Computing solver OpenTelemac. He received a Bachelor’s degree in Mechanical Engineering from University of Science and Technology Beijing, China, and a Master’s degree in Hydraulic Engineering from Ecole Polytechnique in France.
