As part of the program to improve water quality in Narragansett Bay, the Narragansett Bay Commission has issued to CB3A joint-venture notice to proceed with the work on the Pawtucket Tunnel Project. This joint venture comprises CBNA, a US-based subsidiary of Bouygues Travaux Publics, and local civil works contractor Barletta Heavy Division. The contract is worth €394M (Bouygues Travaux Publics’ share is €256M).
Located in the Rhode Island Delta, approximately 75km south of Boston, the Pawtucket Tunnel Project is the first part of phase 3 of the Bay’s water management modernization program (Phase IIIA). CB3A is responsible for the design and construction of the tunnel and its ancillary structures.
The 3.5km long (11,600ft) main tunnel will be excavated along the Seekonk River using a TBM specially designed to accommodate the varied geology of the route. Its 9m (30ft) internal diameter will enable it to collect and store a significant proportion of the region’s rainwater, waste water and industrial water pending treatment by the water treatment plant.
The project also involves the excavation of three main shafts, one of which will serve as a pumping station and supply the existing treatment plant. 4 drop shafts will also be built to collect water, as well as their connecting tunnels to the main tunnel.
Carried out in the heart of an urban residential area, the project will be subject to measures designed to protect the environment and minimize the impact of the work on local residents.
CB3A will be supported by engineering company Aecom to carry out the design and will also promote local employment and the integration of local businesses when organizing the work.
The contract is for a period of 48 months.
The three-phase CSO program kicked off in 2001 with construction of a three-mile long, 26ft wide deep-rock tunnel under Providence to store stormwater runoff. Phase II, completed in 2015, added CSO interceptors to the Providence Tunnel, several sewer separation projects, and a wetlands storage facility. The final phase is focused on the construction of the Pawtucket Tunnel underneath the communities of Pawtucket and Central Falls. The tunnel, which will be is designed to store 58.5 million gallons of combined sewer overflows.
The tunnel is expected to be operational in 2026.