Sanitation District No.1’s Western Regional Conveyance and Storage Tunnel, Charting a New Direction for Control of Sanitary Sewer Overflows

Sanitation District No. 1 Northern Kentucky (SD1) is responsible for the collection and treatment of Northern Kentucky's wastewater, as well as regional storm water management. SD1 is the second largest public sewer utility in Kentucky with a wastewater service area that covers approximately 187 square miles and a storm water service area that covers approximately 217 square miles. These services are provided to more than 29 municipalities and unincorporated portions of Boone, Campbell and Kenton counties. SD1 had been experiencing sanitary sewer overflows from their collection system in the Lakeview Pump Station Area.SD1 planned a new Western Regional Water Reclamation Facility (WRWRF) on the banks of the Ohio River. The challenge was to convey flows from the collection system, especially the Lakeview area to the WRWRF. The District evaluated both a force main and a tunnel option and concluded that a storage and conveyance tunnel would give them more flexibility and the option to store excess wet weather flows. The concept was that the tunnel would relieve stress on the current system and add capacity for future growth. The tunnel provides 14 million gallons of wet weather storage. Flow from the existing interceptor system has been diverted to the tunnel and fourteen older pump stations are planned to be eliminated, thus increasing energy efficiency.The tunnel construction began in June 2009 and ended in Aril 2012, the total construction cost was $110 million. The depth of the tunnel is 300 feet at the deepest section and is tunneled through Kope Formation Shale and limestone.