Combined Sewer Overflow in Boston’s North Dorchester Bay

Sorensen Installs Control Systems for Hydraulically Operated Gates In Tunnel

Combined Sewer Overflow hydraulic gate control panels

Barletta Company of Massachusetts selected Sorensen Systems to furnish six hydraulic gate operating systems as part of the North Dorchester Bay Combined Sewer Overflow (CSO) Tunnel Project. The tunnel project was one of the final phases of the Boston “Big-Dig” project. The CSO project provided a system to hold up to 19 million gallons of combined sewer and storm water overflow. At the time, it was the most expensive public works project in the United States.

Combined Sewer Overflow Part of the Big Dig

The sewer overflow project was part of the Central Artery/Tunnel Project. Which was known unofficially as the Big Dig. The CSO project rerouted part of Interstate 93. Then, with the construction of the Ted Williams tunnel, extended Interstate 90 to Logan International airport. Finally, the project contributed to the creation of the Rose Kennedy greenway. A major concern for the state was how the combined sewer overflows currently discharged. At the time, there were six outfalls along South Boston’s public beaches. The design of the sewer tunnel eliminated the combined sewer overflow to the Bay. Which then protected beaches, shellfish beds, and other sensitive waters.

Combined Sewer Overflow precast concrete vaults containing hydraulic gate control systems

Precast Concrete Vaults Contain Gate Operating Control System

First, Sorensen Systems needed to discover a method for equipping six precast concrete vaults with a hydraulically operated stainless steel gate operating system. This system comprised a hydraulic power unit, hydraulic accumulator, remote control panel, accumulator isolation ball valve, and associated wiring and accessories. Subsequently, Sorensen Systems placed each operating unit inside the precast concrete vaults. Then, the team transported the individual vaults to Sorensen System headquarters in Northborough, Mass. They proceeded to outfit each vault with the operating system one at a time. Since each vault exceeded the size limits of the fabrication facility’s overhead door, they installed a larger door to accommodate the oversized vault. Upon finishing each unit, the company delivered them to the installation site. Sorensen Systems took responsibility for conducting on-site start-up and providing O&M training.