Oakley Station CSO 551 and CSO 553 Separation Sewer

Cincinnati’s Hamilton County was encumbered by a legacy sewer system where two Combined Sewer Overflows (CSOs) discharged more than 66 million gallons of polluted water into the Duck Creek each year. MSDGC’s long-term goal for these two CSOs was to eliminate 80% of the annual CSO volume by 2020, the trenchless approach completely eliminates any CSOs at these two locations. The proposed solution in the Long Term Control Plan was projected to cost $17.5 million.

During the design of the adjacent 75-acre Oakley Station project, IBI Group recognized that there was an opportunity to separate a significant portion of the storm water that is tributary to the CSOs. By changing the drainage pattern and intercepting the drainage with a large storm sewer constructed using trenchless approaches, the project and adjacent areas could drain directly to the creek, bypassing the combined system.

This was the first design-build procurement for the MSDGC and this delivery method allowed IBI Group to propose a fast-tracked plan that would enable the client to reach this goal seven years ahead of schedule and at less than half the budget. In addition to the savings to the client, 462 million gallons of combined sewer overflow was prevented from entering Duck Creek.