DC Clean Rivers CSO mega-project
  • Herrenknecht

28 October 2015: Excavation is progressing in Washington DC, USA, on the 823m long First Street Tunnel by the Skanska/Jay Dee JV, using a refurbished Herrenknecht EPBM. The short stretch of CSO tunnel, which will eventually be part of a 19,750m-long continuous network of new conveyance tunnels under the US capital, was broken out of the larger North East Boundary Tunnel (NEBT) contract in order to facilitate earlier completion in what is a particularly flood-prone neighborhood. Ground freezing is being used to support unstable water-bearing soils in the upper level drop shaft excavations that also form part of the First Street works. A total of four tunnels are either completed, in construction, or entering procurement. Future construction of the planned Potomac Tunnel is not yet finalized.

References
DC calls qualifiers for city’s longest tunnel - TunnelTalk, September 2015
DC prepares for Anacostia EPBM launch - TunnelTalk, January 2015
DC Water scales back CSO tunnel plans - TunnelTalk, January 2014
Green surge threatens CSO storage solution - TunnelTalk, June 2013

Snapshot

DC Clean Rivers CSO mega-project

John McClung for TunnelCast
Project: Clean Rivers, Washington DC
Total Cost: US$2.6 billion
Client: DC Water
First Street Tunnel:
(in construction)		 823m x 7.1m i.d., US$157m
Skanska/Jay Dee JV
TBM Lucy
(refurbished Herrenknecht EPBM)
Anacostia Tunnel:
(in construction)		 3,800m x 7.1m i.d, US$253.9m
Impregilo/Healy/Parsons JV
TBM Nannie
(Herrenknecht EPBM)
Blue Plains Tunnel:
(completed June 2015)		 7,193m x 7.1m i.d., US$330.5m
Traylor/Skanska/Jay Dee JV
TBM Lady Bird
(Herrenknecht EPBM)
NE Boundary Tunnel:
(in procurement)		 7,925m x 7.1m i.d., US$500 million (estimated)
Interviewed: George Hawkins
DC Water CEO
Carlton Ray
Director, Clean Rivers Project
Scott Hoffman
Project Manager, Skanska/Jay Dee