Second breakthrough for DC CSO mega-project
DC Water records its second major TBM breakthrough as part of the US$2.6 billion effort to reduce CSO overflows and flooding in Washington DC.
Excavation of First Street Tunnel completed
The refurbished Herrenknecht EPBM, owned by the Skanska/Jay Dee contractor joint venture that was awarded the accelerated contract in October 2013, broke through into the reception shaft at the end of its seven month long, 823m drive, on December 22 (2015).
TBM Lucy mined under First Street, NW, from Channing Street to Rhode Island Avenue, to complete the drive. The contract was broken out early from the 7,925m long Northeast Boundary Tunnel that it will ultimately connect with. These tunnels, along with the completed 7,200m Blue Plains Tunnel and the under construction 3,800m Anacostia Tunnel will create a continuous 20km connection with the Blue Plain Wastewater Treatment facility by 2022.
“We are pleased to reach this important milestone in the project and are grateful for the continued patience of the impacted community,” said DC Water CEO and General Manager George Hawkins. “We will continue to work with the neighborhood to complete this essential project as soon as possible to provide flood relief for residents.”
When it is commissioned later this year the First Street Tunnel will store and then pump combined sewage up into the existing sewer system during and after rainstorms to keep it off of streets and out of basements. It is designed to mitigate flooding from undersized sewers in the Bloomingdale and LeDroit Park neighborhoods.
Scott Hoffman, Skanska/Jay Dee Project Manager for the First Street Tunnel, said: “We’re proud of the end result, and the positive impact it will have on the community: it’s a great accomplishment.”
TBM Lucy is the second machine to complete her drive this year. In July, TBM Lady Bird completed a two-year, 7,200m drive to complete excavation of the Blue Plains Tunnel.
TBM Lucy will now be dismantled and 99% recycled. Work now continues to connect the existing sewers along First Street, NW, to the new tunnel.
6 Jan 2016