Muskingum River Sanitary Sewer Force Main Project—Key Concepts for a Successful HDD River Crossing Project from the Owner’s Perspective

The city of Marietta, Ohio, was facing significant challenges to replace an aging 10-inch diameter cast iron sanitary sewer force main that was installed under the Muskingum River in the 1950s. The existing force main was in poor condition and significantly undersized and at least partially responsible for causing sanitary sewer overflows along Gilman Avenue on the west side of Marietta during relatively minor wet weather flows. City officials authorized a sanitary sewer study and modeling and final report which recommended the replacement of the aged, undersized 10-inch cast iron force main. During construction, 1,960 lineal feet of a larger 16-inch diameter fusible polyvinyl chloride pipe (FPVCP) DR-21 force main was installed adjacent to the Harmar Lift Station and very near the confluence of the Ohio River. This horizontal directionally drilled (HDD) river crossing project was very complex and had many scheduling and site constraints and challenges; however, it was completed on time and under budget. This was accomplished by having the city select and obtain the right team of professionals including AECOM as Engineer of Record, DRS Enterprises, Inc. as HDD contractor, Inrock Guidance Systems, Inc. as specialty subcontractor responsible for steering, guidance, and tracking services, Underground Solutions, Inc. as supplier and specialty subcontractor responsible for staging, assembly, and installation of the 16” diameter FPVCP force main, and Pickering Associates as the consultant to provide construction management and inspection services. This paper will summarize the key concepts that were critical to the success of this extremely challenging HDD project under the Muskingum River and its location at the river’s confluence with the Ohio River. This project also required the FPVCP to be assembled and staged along the very popular Multi-Use River Trail in the heart of the historic downtown district during peak tourism season for the city of Marietta.