ANALYSIS OF HYDRAULIC MEASURES TO REDUCE THE IMPACT CAUSED BY STRUCTURAL METHODS TO CONTROL AQUATIC NUISANCE SPECIES (ANS) MIGRATION IN CHICAGO AREA WATERWAY SYSTEM (CAWS)

The Chicago Area Waterway System (CAWS) is a set of manmade channels that is controlled by hydraulic structures whose operation is primarily based on water levels, power generation and water quality conditions. A hydrologic management plan has been proposed to mitigate the migration of Aquatic Nuisance Species with the help of control sections to hydraulically separate the Mississippi River watershed from the Great Lakes (U.S. Army Corps of Engineers 2014). Certain operational rules were proposed to the existing hydraulic structures plus some additional ones proposed for the control sections to guarantee navigation along the system and to mitigate flooding in some areas in the CAWS. The analysis was performed using the METROFLOW Urban Hydrology model developed by the University of Illinois (UIUC-MWRD, 2014) along with the one-dimensional HEC-RAS river model (US Army Corps of Engineers 2010), assuming that the Tunnel and Reservoir Plan (TARP), for flood reduction and CSO’s control, is fully operational by 2029. The analysis was performed for critical lake elevations under both dry and wet weather conditions, on a monthly time scale. These numerical simulations demonstrate the importance of the operation of the controlling structures at lakefront in extreme lake levels to mitigate the impact of flooding and to maintain navigation along the CAWS while preventing the potential migration of ANS.