The Black River Tunnel in Lorain, Ohio, is a combined sewage overflow (CSO) storage tunnel that extends through bedrock over 150 ft below ground along the bank of the Black River, helping to keep sewage overflows out of the Black River and Lake Erie.
In 2008, NTH Consultants was chosen to provide geotechnical and tunnel engineering services, including a two-phase geotechnical and hydrogeologic investigation, design of the temporary and permanent liner systems for the tunnels and shafts, preparation of technical specifications, and opinions of probable construction costs. NTH assisted the City of Lorain with initial route planning for the tunnel. Based largely on NTH’s advice and input from the City, the team chose an alignment that maximized the use of the City’s existing easements and eliminated crossings under the Black River.
Over the next few years, NTH completed a two-phase geotechnical investigation that included over 900 lf of soil drilling and 1,300 lf of rock drilling. With the field investigation underway, the NTH tunnel team began designing the primary and secondary lining systems for both the tunnel and the shaft structures. Construction began in 2012 by Super Excavators using a Robbins TBM.
Now the over 1-mile long, 23-ft diameter Black River Tunnel is nearing completion. The 19-ft diameter cast-in-place final tunnel lining is expected to be complete in April, and the concrete lining of the shafts is nearly finished as well. Final completion is scheduled for December 2016.