BOSTON, MA — Stantec has been selected to lead design services on Phase IV of the Boston Water and Sewer Commission’s (BWSC) East Boston Sewer Separation project. The project is part of a comprehensive 30-year initiative to reduce pollutants discharged to Boston Harbor and its tributary waters and to modernize water infrastructure in the rapidly developing neighborhood.

Historic cities like Boston face a unique challenge in effectively managing stormwater as many older systems feature combined sewers that carry both stormwater and sewage. During heavy rainfall, these systems are prone to being overloaded and are designed to release excess flows into local bodies of water. To better manage overflows and protect water quality — particularly as rainfall events are becoming more frequent and more intense — the Massachusetts Water Resources Authority is implementing a Combined Sewer Overflow (CSO) Control Program that involves modernizing this infrastructure with the latest technology. East Boston is among the communities at the center of this effort.

“In collaboration with the Massachusetts Water Resources Authority as part of its CSO Control Program, the East Boston Sewer Separation project represents a critical step toward improving water quality in Boston Harbor,” said John Sullivan, BWSC Chief Engineer.

The work will enhance water, sewer, and storm drainage infrastructure, which is vital in supporting the ongoing growth and prosperity of the East Boston community. Phase IV of the project involves separating approximately 230 acres of combined sewer area, along with installing new storm drains, updating existing sewers, replacing adjacent aging water mains, and modifying existing regulator structures. As lead designer, the Stantec team will complete conceptual designs, hydraulic modeling, master planning, and final design documents, including pre-construction services.

“Water infrastructure plays a crucial role in a city like Boston, where factors such as climate change, population growth, and new development only further stress existing resources,” said Mike Carroll, Stantec Project Manager. “We’re proud to continue a decades-long relationship with the BWSC to improve the historic and essential waterways while helping modernize this infrastructure across several neighborhoods to support residents and businesses into the future.”

Stantec has partnered with the BWSC for more than 30 years, collaborating to complete some of Boston's most complex and demanding sewer separation and infrastructure improvement projects. Stantec has supported the BWSC with planning, design, and construction phase services on more than 40 contracts with a combined value of $420 million. The scope of these projects includes installing 51 miles of water main piping, 29 miles of new sanitary sewer, and 41 miles of new storm drain.

Most recently, the team completed work on Phase III of the East Boston Sewer Separation project where planning and design services were completed in accordance with a fast-track schedule. Using the commission’s hydrologic/hydraulic model, Stantec prepared plans for the installation of 9,000 feet of new water main, 4,000 feet of new sewer, and 7,300 feet of new storm drain. The project also involved the rehabilitation of 2,300 feet of existing wastewater piping and the modification of three regulator manholes to improve hydraulic performance and reduce overflows.