The Massachusetts Water Resources Authority on June 25 awarded a $4.9-million contract to the Boston office of Stantec for engineering services on the 45-year old, 60-mgd West Roxbury Wastewater Tunnel. The 12-in thick cast-in-place concrete lining in the 12,500-ft long, 84-in dia. rock tunnel, which serves about 125,000 homes and businesses, is eroded due to hydrogen sulfide corrosion.
J.F. White, Framingham, Mass., will inspect the tunnel, which has two portals and a 220-ft deep shaft, this fall to help determine the extent of the problem and the relining solution. "The 12-in liner is structural and as of a decade ago the concrete was compromised for the first 1,500 ft from the New Haven Street junction chamber," says William B. Powers, Stantec project manager. "Other portions show only corrosion to the veneer." Stantec is working with local offices of Hatch Mott MacDonald for possible new tunnel routes and Brown and Caldwell for hydraulic modeling.