Visitors and businesses along the waterfront will catch a break this spring, as repairs to the Water Street sewer line will be postponed until after Thanksgiving because of a dispute between the town and a contractor over the latest turn in the long-running project.
Work to address the settling of underground piping was expected to start in February, but the contractor, Northern Construction, and the town have been unable to reach agreement over how – and even if – the repairs should be done. While both parties continue to talk, the dispute has delayed the project to the point where it’s too late to start without disrupting the tourist season.
“We made a commitment to the businesses on the waterfront that we would not be doing any work after Memorial Day,” said Town Manager Derek Brindisi. “The work could take three months or more, depending on what they find when they start. And when you look at the calendar now, the right thing to do is to wait until winter.”
The issue is that part of the new sewer line has settled several inches, creating a section of pipe with a low point and an upward pitch. That’s a problem for a line that depends on gravity to keep waste flowing downhill.
“We can’t accept it as is,” said William Coyle, director of the town’s Department of Public Works.
The Water Street project – which has doubled in cost – has a long and troubled history.
With a low bid of $4.5 million Northern Construction of Palmer won the contract in 2022 to install a quarter-mile section of 30-inch sewer pipe under Water Street to replace the 1960s vintage sewer line that runs under the edge of the harbor. The town was worried that if the old line failed and spewed sewage into the harbor it would create an environmental disaster and be difficult to repair.
Work began in December 2022 and was supposed to be finished by the end of June 2023. But in March 2023, during the first phase of excavation, groundwater problems, shifting soils, and damage to the street, sidewalks, and five buildings on Water and Chilton streets forced a shutdown of the project.
One building was damaged so badly that it had to be razed. The owners of the affected buildings are suing both the town and Northern Construction, seeking more than $5 million in damages.
It is that first section of pipe, from just south of the rotary near the visitors center along Water Street to in front of Mamma Mia’s restaurant, that has settled.
After the March 2023 debacle, an engineering review led to changes in construction methods, with additional groundwater monitoring and relief wells placed within the working trench to prevent further damage. With those modifications in place, the project resumed briefly but was put on hold for the 2023 tourist season. Work resumed in January 2024 and proceeded without major problems. The line was finished in May 2024. By then, the settlement issue was already being tracked.
In a June 24, 2024, letter to Northern Construction, the town’s engineering firm (Environmental Partners) reported that a survey of the line found an “upward pitch” between two manholes in the first section installed, “resulting in a stagnation or slow movement of wastewater flows, thereby increasing the likelihood for deposition of solids within the sewer (pipe) and the potential for an (overflow) event to occur. The differences in elevations are not acceptable. Therefore, we direct that Northern expeditiously, and no later than 10 days of receipt of this letter, submit a corrective work plan and a schedule that outlines the approach for performing this corrective work.”
Northern Construction disputed that notice and did not submit a repair plan.
“Collectively, the Town of Plymouth, Environmental Partners and Northern all watched this area of the project progressively settle since it was installed in early 2023,” Northern Construction wrote in an October 8, 2024, letter to the town’s engineer. “At no point during those discussions did Environmental Partners or the Town ever state or otherwise indicate that Northern was at fault or obligated to correct the issue. While we agree that the current vertical position for portions of the (pipe) differ from the positions depicted in the design documents, we disagree that the current position is the result of noncompliant construction.”
Northern Construction told the town the settlement was minor. It said repairs were not necessary and could be counterproductive, causing more settlement and potential property damage. Instead, the company suggests periodic maintenance of the sewer line, to remove solids that build up in the settled area. That would be sufficient to keep the system operating properly, it said.
The town rejects the maintenance approach, because just cleaning the line twice a year won’t fix the underlying problem, Coyle said. Beyond the cleaning costs, which he estimated would be $10,000 to $15,000 per year, every year the line operates, allowing solids to build-up reduces the diameter of the pipe, and thereby the flow capacity of the line.
“The pipe is functioning now, but given the way the town is growing, we are going to need that capacity in 20 or 30 years down the road,” Coyle said.
Before proceeding with repairs, Northern Construction wanted a new engineering review of the subsurface site conditions in light of the settlement problem and adjoining property damage. It hired GZA GeoEnvironmental Inc. of Providence, RI, which completed its report in January. The firm found that previously unknown soil conditions in the area likely caused the settlement problem. It advised against digging another trench to try and repair the pipe.
“As indicated by GZA in its letter, Northern would likely experience similar settlement issues if it proceeds with the cut and cover design. Consequently, GZA is unwilling to provide us with a dewatering plan that would ensure that the reinstalled pipe and manhole would not settle,” Northern Construction wrote to the town’s engineer on Jan. 21. “We therefore reiterate our request that the Town either agree to leave the sewer line as is or provide a redesign utilizing alternative methods such as micro tunneling or pipe jacking,”
When the sewer line project was first proposed, town engineers explored various methods of construction. Micro tunneling and pipe jacking. – which involves digging a pit at one end of the site, then boring horizontally through the ground and pushing sections of pipe into place – was considered but rejected in favor of the “cut and cover” approach. That entailed digging a deep trench, installing the pipe, and then backfilling the trench.
While Coyle was not working for the town when that decision was made, he said micro tunneling and pipe jacking were far more expensive and ultimately would still have been disruptive to the Water Street area. He also questioned the accuracy of those approaches to place the pipe precisely where needed. The town’s decision to choose the cut and cover method “was the right choice for both cost and constructability,” Coyle said.
Town officials also dispute the premise that “unknown” soil conditions were the cause of the settlement and adjoining property damage. The town asserts the repair work can be completed with the same “cut and cover” method, because the water management changes put in place after the March 2023 incident worked well.
“It was a complete contrast with what happened in the second phase of the work, which was accomplished without any problems,” Brindisi said. “We expect the project to be completed as designed.”
Northern Construction still disputes the need for repairs and has put the town on notice that it is “proceeding under protest and expressly reserve all rights under the contract and at law. Nothing contained in this letter shall be construed as a waiver of any such rights.”
Next week, a survey crew from Northern Construction is expected to open the manholes on Water Street and measure the elevations of the sewer line again by laser, to try and pin down how many linear feet of the line needs to be reset.
Throughout the starts and stops of the troubled project, Northern Construction claimed the original cost of the project had doubled to $9 million. The town ultimately settled with the company, agreeing to pay an additional $2 million above the original $4.5 million price tag.
Repair costs will be covered by $1.6 million the town has held back from Northern Construction, pending the post-construction inspection period, to cover potential issues like the settlement defect.
There is no date set yet for the winter work to begin. When it happens, sewage will be redirected through the old pipe, which remains under the harbor.
“We have had some hiccups, but I believe this is the one of the most important environmental projects the town has done in decades,” Brindisi said.
Michael Cohen can be reached at michael@plymouthindependent.org.