Massachusetts Water Resources Authority


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June 22, 2000

MWRA Completes Mining of MetroWest Tunnel's Eastern Segment

On Friday evening, June 16, the Massachusetts Water Resources Authority (MWRA) reached yet another significant milestone in constructing the 17.6 mile MetroWest Water Supply Tunnel. Shea-Traylor-Healy, the joint venture contractor, completed mining the second of the project’s four major tunnel legs. The 0.8 mile long eastern tunnel segment was mined using a 16-foot diameter tunnel boring machine. Mining began in January 2000 from Shaft 5A in Weston, adjacent to the Massachusetts Turnpike/Rte. 128 interchange. The eastern segment will link the MetroWest tunnel to the MWRA’s Loring Road covered storage tanks and the existing City Tunnel.

Mining of the MetroWest Water Supply Tunnel’s first leg from Framingham to Southborough was completed in July 1999. Only 600’ of the 4.9-mile western segment from Southborough to Marlborough remain unmined. The final leg from Framingham to Weston is expected to be completed by the end of the year and will mark the completion of all project mining. Over the next three years, the tunnel, ranging in depth from 200 to 400 feet, will be lined with concrete, pressure tested and disinfected before put into service.

Construction progress of the MWWST stands at 60%. The project is on time and projected to be completed for less than the original $728 million estimate. Once complete in 2003, the 60-year-old Hultman Aqueduct will be taken out of service and rehabilitated to reinforce and enhance the entire water transmission system. The tunnel project is just one part of the MWRA’s $1.7 billion water supply improvement program which includes watershed protection, local distribution pipe upgrades and construction of a new, state-of-the-art water treatment plant and covered storage facilities.