Combined Sewer Overflow (image) Cary Institute of Ecosystem Studies Share Print E-Mail Caption This is a combined sewer overflow on Chicago's North Shore channel. Credit John Kelly Usage Restrictions To be used to promote this press release. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.