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Mass Ave. Sewer Separation Project

street level view Newbury Street
Mass Ave.


The Boston Water and Sewer Commission's (the Commission) Mass Ave. Dorchester and Roxbury Projects involve separating the combined sewer system in the Massachusetts Avenue area of Dorchester and Roxbury.The purpose of this project is to reduce pollution levels in Boston Harbor by substantially decreasing the number and volume of combined sewer overflows (CSOs) into the Fort Point Channel and Boston Harbor.The work is being completed under two contracts.

Combined sewers are found in many older cities and carry both sanitary sewage and stormwater in the same pipe. During dry weather, sanitary flows are conveyed to interceptor sewers that transport the sewage flows to a wastewater treatment facility. During wet weather, the stormwater gradually takes up the greater portion of the space in the pipe and, depending upon the duration and intensity of the storm, may exceed the capacity of the combined sewer system. The excess combined flows are transported to overflow conduits that discharge into a local body of water, in this case the Fort Point Channel and Boston Harbor.The resulting discharge of both sanitary sewage and stormwater flows from these overflow pipes is known as a CSO (combined sewer overflow).

Overflows from the Mass Ave. Dorchester and Roxbury area discharge to the Fort Point Channel through the BOS 070 outfall. This sewer separation project will replace the existing single combined system with two separate systems one for sanitary sewage and one for stormwater. When construction is complete, sanitary sewage will be conveyed to the MWRA's Deer Island Wastewater Treatment Plant, while stormwater will be discharged to the Fort Point Channel via the Dorchester Brook Conduit resulting in a substantial reduction in CSOs. As a result, the impact on the Fort Point Channel and Boston Harbor from the harmful effects of pollution from CSOs will be substantially reduced.

In addition, the Commission is concurrently replacing water mains in the area to minimize impacts by reducing the need to return at a later date to complete the work.

Project Area

The Mass Ave. Dorchester Sewer Separation Project encompasses an area roughly bounded by Massachusetts Avenue to the south, Columbia Road and Roseclair Street to the east, Mt. Vernon Street and Enterprise Street to the north and South Bay Center to the west. The Mass Ave. Roxbury Project encompasses an area roughly bounded by Norfolk Avenue to the south, South Bay Center to the east, Southampton Street to the north and Gerard Street to the west. A map of the contract areas is attached for reference. Land use in the project area is characterized by residential neighborhoods, commercial and industrial businesses, distribution centers, food wholesalers and small businesses.

Scope of Work

The work includes installation of the following:

Mass Ave. Dorchester (#12-309-008)

  • 11,700 linear feet of sewers and drains
  • 3,870 linear feet of water mains

Mass Ave. Roxbury (#12-309-004)

  • 19,795 linear feet of sewers and drains
  • 9,660 linear feet of water mains

Building Disconnections

In addition to separating combined sewers in the street, this project will disconnect as many individual building downspouts and laterals from sewers as is cost effective. Building laterals are pipes that connect a building's internal plumbing to pipes in the street. Many older buildings in the area have an internal pipe that collects stormwater from the roof and discharges it into the building sewer lateral. Downspouts also collect stormwater from the roof in pipes that run down the sides of buildings. In some cases, these downspouts discharge into the sewer, rather than splashing to the ground. Since the purpose of this project is to remove as much stormwater from the sewer system as possible, these building downspouts will be disconnected, where feasible. This work will be coordinated individually with building owners, as necessary.

Mass Ave.

Temporary Restoration

Temporary restoration of roadways, sidewalks and other areas disturbed by construction will be completed under this contract. Permanent restoration will occur under a separate paving contract.

Overall Schedule

Construction start (both contracts) June 2012

Construction completion:

  • Mass Ave. Dorchester spring 2013
  • Mass Ave. Roxbury spring 2015

Project Coordination and Activity

The Commission is committed to working closely with the Mayor's Office; elected officials; Boston Public Works Department (BPWD), Boston Transportation Department (BTD) and other City departments; the Massachusetts Bay Transportation Authority; the MWRA and other public and private utility companies; state and federal regulatory agencies; and, most importantly, with abutters to ensure the project is successfully completed. Extensive coordination with National Grid and NSTAR will be required to facilitate utility relocations or replacements, as necessary. Effective coordination will also help mitigate many short-term construction related impacts that may be associated with the project.

The Commission will adhere to all city and state regulations and ordinances governing construction in public roadways. All dust, debris and excavate will be strictly controlled and monitored.

Community Relations

The Commission is committed to a proactive community relations program during construction of this project. The program is designed to keep residents, businesses and elected officials informed about the project by holding public meetings, placing notices in local newspapers and posting updates on the project webpage, which can be found on the Commission's website at Prior to the start of construction, public meetings will be held to introduce the contractor and provide specific information and anticipated schedules for upcoming work. In addition, before construction begins on a street, a notice will be sent in the mail announcing the work to be performed on the street. Project staff will meet periodically with residents, businesses, civic groups, and elected officials to provide updates, as requested or appropriate. Commission staff will work closely with affected neighborhoods regarding issues such as pedestrian and vehicular traffic management, access to residences and business establishments, and maintaining access for deliveries and trash and snow removal.


For further information or questions please contact the following:

Boston Water and Sewer Commission - 617-989-7000

Irene McSweeney, Director of Construction

Steve Callaghan, Project Engineer Mass Ave. Dorchester

Steve Johnson, Project Engineer - Mass Ave. Roxbury

Sean Canty, Intergovernmental Relations Manager

If you have questions or concerns about construction, please contact:

Project Field Office:

Myles F. Johnson, Construction Manager

CDM Smith

50 Newmarket Square, 2nd Floor 617-592-5823

In an emergency, contact BWSC's 24-hour, 7-day a week number at 617-989-7000.