Manchester city leaders and engineers broke ground Monday on the Cemetery Brook Drain Tunnel Project, a major stormwater infrastructure effort designed to prevent street flooding during heavy rains and reduce sewage spills into the Merrimack River. The project, more than a decade in the planning stages, will use a tunnel-boring machine to excavate a new stormwater tunnel more than 2 miles beneath the city.
Background and purpose
Officials say the new tunnel will separate stormwater flows from the citys combined sewer system in parts of Manchester where heavy rains have historically overwhelmed the sewer network. According to Dave Polcari, senior vice president of engineering firm CDM Smith, the project has been on the books since about 2010 and is intended to improve water quality in the Merrimack River while preventing road and property flooding.
"This project has been on the books since probably 2010," said Dave Polcari, senior vice president of CDM Smith.
Mayor Jay Ruais emphasized the local impacts, noting that repeated backing up of sewers during storms will be addressed by the new conduit. "Any time it rained, people had backing up in the sewers in that area," Ruais said. "This is what is going to alleviate the struggles in the long term."
Construction plan and schedule
Crews will operate a large tunnel-boring machine that will run roughly six days per week to excavate the stormwater tunnel. Project leaders expect the drill to reach its two-mile destination in less than a year. The work begins this week and will proceed under planned schedules that engineers say are designed to minimize long-term disruption.
- Project name: Cemetery Brook Drain Tunnel Project
- Primary goal: Separate stormwater from sewer system; reduce sewage overflows and prevent road flooding
- Length: More than 2 miles
- Expected drilling schedule: Six days per week; completion of tunneling in less than a year
Local implications
For residents, the tunnel promises both immediate and long-term effects. In the near term, tunneling operations may bring traffic changes, construction staging, and work-related noise in neighborhoods along the alignment. In the longer term, separating stormwater may reduce sewer backups into basements and decrease the frequency of road flooding during heavy storms. City officials are also pointing to improved river water quality as a public-health and environmental benefit.
Polcari and city leaders framed the work as solving a recurring infrastructure problem: when stormwater enters the combined sewer system during heavy precipitation, the system can be overwhelmed and allow sewage to spill into the Merrimack River. The new dedicated stormwater tunnel is intended to carry excess rainwater away from the system, reducing that overflow risk.
| Item | Detail |
|---|---|
| Project start | Groundbreaking and tunneling began this week |
| Planned tunneling frequency | Approximately six days per week |
| Length | More than 2 miles |
| Expected tunneling completion | Less than a year |
What comes next
After tunneling is complete, additional work will be required to connect the new stormwater tunnel to the existing drainage network, implement any necessary road restorations and complete environmental mitigation measures. City officials and the project team have said the long-term payoff is fewer flooding incidents and improved water quality, but they also caution that significant construction is required before those benefits are fully realized.
Officials involved in the project have highlighted its long planning timeline and said the tunnel represents a strategic investment in Manchesters infrastructure. Residents affected by construction or concerned about flooding or water quality can look for project updates from city communications and CDM Smith as work progresses.
