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Ottawa CSO - LTCP - City of Ottawa

Ottawa, Illinois

The purpose of this project was to develop and gain Illinois Environmental Protection Agency (IEPA) approval of a CSO (Combined Sewer Overflow) Long Term Control Plan (LTCP). The challenge was to find a cost-effective way of reducing an average of 26 CSOs per year to the IEPA limit of four. The project involved comprehensive system characterization of the combined sewer network, water quality sampling of two rivers, and complex modeling of both the collection system and receiving waters. The detailed investigation, modeling and creative engineering solutions provided the city with the most cost-effective program that complied with regulatory policy. The plan was defensible and also resulted in an extended schedule for compliance, easing the overall burden to the community and its residents.