Yesterday TBM Elaine broke through after excavating a 2km tunnel more than 30.5m below the city’s North Hill neighbourhood.

The machine was launched in April this year to build Akron’s second largest storage tunnel. The 5m-diameter tunnel has a 10.3 gallon capacity to hold and convey combined sewage during heavy rain events until it can be treated at the Water Reclamation Facility.

The tunnel is expected to go into operation in December of 2026.   

The Northside Interceptor Tunnel is the penultimate project required by the city’s federal consent decree with the Ohio Environmental Protection Agency (EPA) and the US EPA. The final project remains subject to court proceedings.  

“The city’s first tunnel, the OCIT, has had significant positive impacts to both our waterways and our residents,” said Mayor Shammas Malik. “During heavy rain events, we are able to keep 467 million gallons of combined sewer overflow out of our waterways. With the addition of the NSIT, we will be able to capture and treat 99.7% of combined sewer overflow events in a typical year. This is an outstanding achievement and one we are incredibly proud of. As we approach the end of our massive sewer system overhaul, I want to thank all our employees, the Ohio EPA, the US EPA, and all the stakeholders from our community who have made this incredible transformation a reality here in Akron.”   

Originally the tunnel was to be 6m in diameter and 3km long to hold 23 million gallons but the city sought the support of Ohio EPA and the US EPA to ‘right-size’ the tunnel to provide similar environmental impacts at a fraction of the cost to ratepayers. In April 2023, the Court issued an order amending the city’s Consent Decree to save ratepayers US$40m in costs.  

The TBM was named after Elaine Marsh, who worked with communities, regulators, and local governments to do the complex, collaborative work of dam removal and waterway renewal all along the Cuyahoga River.  

Crews will now complete the tunnel shafts and finalise connections to the tunnel before it goes into operation.