On March 15, the NEORSD Board of Trustees awarded the construction contract for the next of its tunnels, the Westerly Storage Tunnel (WST) to a joint venture of Jay Dee/Obayashi. Jay Dee/Obayashi’s bid was $135,000,000. The project includes approximately 9,600ft (2.92km) of 25ft (7.62m) i.d. CSO storage tunnel excavated in rock and supported with a steel fiber reinforced precast segmental lining.
In addition to the tunnel, there are three deep shafts of varying diameters and depths (WST-1, -2 and -3). Ancillary work includes gate structures and gate control structures, at both the WST-2 and WST-3 sites, to regulate flow entering the tunnel, approximately 90ft (27.4m) of 46-in (1.17m) diameter sewer, and miscellaneous modifications to existing sewers. The design contract for WST was awarded to a joint venture of Mott MacDonald and MWH Global/Stantec in 2015.