This SAWS joint bid project (CoSA) for the 2017-2022 Bond Program included CIPP rehabilitation of 505 LF of 27-inch RCP along French Creek. The roadway and drainage improvements eliminated an existing low water crossing for O.P. Schnabel Park and improve ingress/egress for park users and the YMCA facilities. The roadway and drainage improvements included adding eight new concrete culverts, headwalls, toe-downs, and aprons. The new roadway and drainage structure was constructed directly over the existing 27-inch sanitary sewer line, further creating future challenges for the existing line. Our design team developed recommendations to support the existing line and its long-term effectiveness, given the collection system area it serves. Ultimately, we recommended the most cost-effective solution, which included CIPP rehabilitation of the existing line and placement of concrete saddles just under the proposed toe-down walls over the pipe. To accomplish the work, the team developed a significant bypass pumping plan within the creek. We coordinated with the City’s Parks Department to maintain access to the existing hike and bike trail network within the project limits, and the improvements had no adverse environmental impacts. A portion of the existing trail system was closed during the sewer construction to ensure a safe work zone for contractors and the public users of the trail network. WGI established armament details to protect four reconstructed manholes within French Creek through coordination with SAWS engineering and the inspection department. WGI performed construction phase and closeout services and oversee completion of the improvements to achieve the proposed design.

Project Highlights:

• Total length: 505 LF
• Pipe size: 27-inch (large diameter)
• Drainage structure conflicts/ floodplain mitigation
• Agency coordination
• Public Coordination for Construction Updates
• Large diameter bypass pumping
• Low-impact rehabilitation design
• Large-diameter sanitary sewer
• CIPP to minimize construction footprint
• Protect sewer line under drainage structure
• Environmental constraints