Planning Board hears multi-utility update on sewer, water mains, electric grid and district energy

Cambridge Planning Board members heard detailed briefings June 10 on sewer and drainage planning, water‑main replacement projects, transmission and distribution plans from Eversource, and Vicinity Energy’s electrification projects in Kendall Square.

Board Chair Mary Flynn opened the utility update, which combined reports from the Department of Public Works (DPW), the Water Department, Eversource, and district‑energy provider Vicinity Energy. Presenters described completed work and projects planned over the next decade, highlighted where city funding supports construction, and answered questions from board members about flood risk, sewer separation, and grid capacity.

The update matters because the projects affect flood risk and water quality, the city’s ability to support new development, and the local transition from fossil fuels to electric heat sources. DPW Commissioner Kathy Watkins told the board the city is pursuing a 10‑year approach to sewer and drainage projects while also operating five‑ and 10‑year plans for sidewalks, streets and lighting. She said a new sidewalk inventory rated about 43% of sidewalks as in good condition, 49% in fair condition and 7% in poor condition; the city also identified more than 3,000 pedestrian ramps that do not meet current accessibility standards and is planning targeted contracts to upgrade ramps.

On combined sewer overflow (CSO) work, DPW described a coordinated plan with the Massachusetts Water Resources Authority (MWRA) and Somerville. Staff said the city has reduced CSO discharge volumes over the last 30 years — about an 85% reduction to the Alewife Brook and a 98% reduction to the Charles River — and is developing a Long‑Term Control Plan that will be drafted by the end of 2025 and finalized by January 2027. The plan will combine sewer separation where feasible, green stormwater infrastructure, inflow and infiltration repairs, storage and conveyance projects. DPW highlighted large projects already under way, including stormwater retention and infiltration measures constructed with new school work (a 100,000‑gallon retention area and a roughly 1,250,000‑gallon underground stormwater tank at the Tobin School site) and a Parking Lot 6 tank in the Port/Central Square area that activates for large storm events.

Watkins also reviewed sea‑level rise and storm‑surge planning. The city is planning improvements around the Amelia Earhart and Charles River dams and evaluating pathways where harbor water could enter the city; those studies feed both infrastructure designs and project prioritization.

Water Department director Rich Holly provided an overview of recent and planned water‑main replacements, the reasons the department replaces mains (age, leak history, water quality and fire flows), and recent project outcomes. In‑house work on Maple Avenue installed 1,500 feet of 8‑inch ductile iron main and raised local hydrant flows from about 900 gallons per minute (gpm) to about 1,900 gpm. Montgomery Street work transferred service from an 1870 six‑inch cast iron main to a 12‑inch main, increasing hydrant flows in that area from the mid‑900s gpm to about 1,600 gpm. Upcoming or ongoing projects noted by the department include Dana Street (replacement of a 10‑inch cast iron main with an 8‑inch ductile iron main), Sharapas Street (about 2,000 feet of 8‑inch replacement scheduled for fall, with 22 lead services to be removed), and a Mass. Ave. project replacing roughly 1,900 feet of main at intersections that will accommodate floating bus stops and the corridor’s planned redevelopment. Holly summarized the water‑department work planned for the year as about 1.28 miles of new main.

On financing, DPW said the bulk of routine infrastructure work is funded by the city through tax revenues and municipal bonds, supplemented by state Chapter 90 funds for roadwork and targeted federal grants when available; both DPW and the water department noted some federal grants are at risk due to changing national budgets.

Eversource representatives described the company’s Electric Sector Modernization Plan (ESMP) and a 10‑year planning horizon for distribution and transmission upgrades. Jason Wright (community relations) and Sofia Zhang (forecasting) said growth in electrical demand in Cambridge is currently driven mainly by large commercial development, particularly life‑science projects. Eversource’s near‑term transmission investments are driven by “step loads” — large, concentrated new demand that can require additional substation capacity or upgrades — and the utility forecasts that winter peaks (driven by electrified heating and EV charging) may supplant summer peaks by about 2035. Eversource highlighted two regional capital programs important to Cambridge: the Greater Cambridge Energy Program (a new underground substation in Kendall Square intended to relieve local substations and support regional growth) and the Underground Cable Modernization Program (UCMP), which replaces aging high‑pressure fluid‑filled transmission cables with modern cross‑linked polyethylene (XLPE) cables. Eversource said Greater Cambridge construction work began in 2025, vault installations are in progress and initial energization is targeted for 2029, and that UCMP route‑selection work and community outreach are underway with construction of selected segments aimed at later years of the plan.

Eversource also outlined its advanced metering infrastructure (AMI) program. The company said network device work on poles will begin in 2025–26 and meter installations in Cambridge are expected to start in mid‑2027; AMI will enable remote outage reporting, near‑real‑time usage data and remote connect/disconnect functions.

Vicinity Energy reported progress on its Kendall Square projects. Chief Sustainability Officer Matt O’Malley said the 42‑megawatt electric boiler in Kendall was commissioned and has been operating since November 2024. Don Sylvia (regional operations) and the Vicinity team described plans for a large water‑source heat pump — a city‑scale system that will extract thermal energy from the Charles River and is targeted for operation by 2028 — and longer‑term thermal‑storage concepts designed to capture low‑cost, renewable electricity (for example, nighttime wind) and shift energy delivery to morning peaks. Vicinity said its Kendall plant has an existing transmission interconnection capability and worked with Eversource and city officials on distribution upgrades to support new customer connections.

Public commenter Heather Hoffman of Hurley Street raised Alewife CSO concerns and said she hoped the city would avoid raw‑sewage discharges into basements and open space. She also asked that decorative light replacements at Lechmere Canal Park match original fixtures and urged removal of double‑pull utility hardware she found unsightly.

Board members asked clarifying questions about funding sources, CSO backflow into private basements, and the pace of sewer separation. DPW responded that most funding for routine projects comes from city sources and municipal bonds, supplemented by Chapter 90 and, where available, federal grants; staff emphasized that a home or building with lower‑level fixtures should install backflow prevention devices because backups can happen when the sewer system is overwhelmed for many reasons. DPW said full citywide sewer separation is not feasible on a short timeline: projects are prioritized for greatest benefit, and some combined areas remain because separation becomes progressively more complex and costly. Eversource said transmission upgrades are a key element of enabling long‑term clean energy imports to the metro area and that the ESMP sets out the company’s path to meet anticipated step‑load and electrification needs.

What’s next: DPW and utilities will continue community and stakeholder outreach; the CSO Long‑Term Control Plan draft is expected by the end of 2025 with a final plan in early 2027; Eversource and Vicinity will continue project‑level outreach for UCMP routing and Kendall system expansions. Several board members asked for repeated updates as projects advance.

Ending: The board took no formal action on the presentations; presenters were invited to return with technical updates and follow‑up answers to specific questions.