The City of Columbus Lower Olentangy Tunnel: Selecting an Alignment to Extend the OARS Tunnel

This presentation will discuss the Planning and Detailed Design phases of the Lower Olentangy Tunnel (LOT) project, which is an extension of the OARS tunnel that began operation in 2017. Both projects are a major component of the City of Columbus's efforts to reduce sewer overflows and improve surface water quality as mandated by the City's two Consent Orders with the Ohio EPA. Once completed, LOT will eliminate combined sewer overflows (CSOs) to the Olentangy River for the typical-year storm and help achieve a 10-year level of service for Designated Sanitary Relief structures (DSRs), Water in Basements (WIBs), and manhole flooding within designated problem areas.