Stantec has advanced its partnership with the City of Lynchburg, Virginia, US, by providing key services for the Blackwater combined sewer overflows (CSO) Tunnel project. 

Construction has already commenced on the $104m project. 

Stantec is delivering construction management, engineering services during construction, and inspection services for the project.  

As climate change leads to more intense rainfall and increased wet weather flow, the initiative is a part of Lynchburg's strategy to mitigate CSO effects.  

The Blackwater CSO Tunnel is expected to help direct overflow away from a local park, reducing discharge frequency and volume. 

The nearly mile-long tunnel, with a finished diameter of 12ft, will be situated between 70ft and 120ft underground in rock formations.  

This will provide approximately 4.7 million gallons of storage capacity.  

Stantec completed the expedited design for the tunnel and pump station in late 2023, after securing a master services agreement with the city in 2022. 

The expedited design is said to have been crucial to align with the construction timeline required by the American Rescue Plan Act (ARPA) grant funding.  

Upon completion, the tunnel is expected to achieve a 98% reduction in CSO systemwide, which will enhance water quality in local waterways and public health along the trail.  

Furthermore, the capacity improvement will support Lynchburg's infrastructure needs for anticipated urban development and growth. 

The Blackwater CSO Tunnel is part of the city’s long-term control plan for CSO and the Virginia Department of Environmental Quality consent order.  

The city is planning to use ARPA grant funds in conjunction with Virginia’s State Revolving Fund to meet its CSO consent order obligations within the next five years. 

Stantec vice-president and wet weather flow sector leader Lin Liang said: “We’re eager to continue supporting the City of Lynchburg to complete its CSO programme. 

“I’m proud of our team’s capability to deliver a fast-paced design project like this. This is a complex project that requires creative thinking and ideas as well as industry-leading experience in deep rock tunnel and pump station design.” 

This development follows Stantec's selection by the Port Authority of New York and New Jersey to lead the preliminary and final design for elements of the Newark AirTrain replacement project last month.