The Marblehead Pipeline Replacement Project in Massachusetts has earned a National Recognition Award from the American Council of Engineering Companies (ACEC) in its 2017 Engineering Excellence Awards competition.
The ACEC award is the latest in a growing list of accolades that the project has earned since its completion in August 2015. Previous awards include American Public Works Association’s 2016 Public Works Projects of the Year and a Silver Award fro ACEC-Massachusetts, which made it eligible for the national ACEC awards competition.
The National Recognition Award will be presented at the ACEC’s gala dinner and awards program on April 25 in Washington, D.C.
“This project removed two badly corroded ductile-iron pipelines from service, ending the risk of a major leak of sewage into Salem Harbor,” said Christopher Barnett, principal-in-charge for the project. “In addition, the new pipes provide improved capacity and redundancy, and are made of high-density polyethylene [HDPE] and other materials selected to provide service for well over 50 years.”
WSP was the prime consultant for the condition assessment, evaluation of alternatives, preliminary and final design and construction services for the Marblehead Pipeline, twin pressure sewers that deliver all wastewater from the Town of Marblehead to the South Essex Sewerage District’s wastewater treatment facility, in Salem. Services also included underwater site investigations, specialized analyses, project management, environmental permit and grant support, cost estimating/scheduling, and construction/resident engineering.
Working out of the firm’s Boston office, the project team included Rachel Burckardt, project manager; and Scott Williamson, project engineer; with help from Michael Berman in the Newark office and Shui-Tuang Cheng in St. Louis.
The nearly $10 million project marked a number of “firsts” in the region.
“This was the first major subsea sewer in New England installed by the ‘float and sink’ method,” Barnett said. “It was also the first major HDPE marine pressure main in Massachusetts.”
He said that HDPE provides longer service life than alternative pipe materials, and avoided the need for marine pile driving associated with conventional ductile iron or concrete pipelines.
The project included successful environmental mitigation measures and monitoring during construction, as evidenced by protection of sensitive eel grass beds close to the pipeline alignment. The project team was also required to look for archeological resources along the pipeline route.
“It was one of the first marine archeology programs focused on identifying Paleolithic soil materials that could indicate human habitation of harbor areas during the period following the last ice age, when sea levels were low enough that present harbor bottom was dry land,” Burckardt said. “Protection of the harbor and its natural and economic resources was a key consideration in planning and execution of this project.”
Construction posed some challenges in an active harbor used regularly by commercial shipping and recreational boating, and careful attention was spent negotiating the concerns of marine fisheries and cultural resource protection agencies.
“The pipelines were installed in one of the busiest recreational harbors in the nation, requiring careful scheduling to minimize conflicts with over 100 small-craft moorings, recreational boating and commercial shipping,” Barnett said.
It was actually a recreational harbor lobsterman who first noticed a potential problem with the pipe in the winter of 2013, when he saw an unusual patch where the ice had melted away, and with seagulls dive-bombing the opening,” Barnett said. South Essex Sewerage District officials soon determined that the melting was caused by a sewer pipe leak underneath the harbor.
Design challenges included the lack of redundancy in the existing sewer system, which required installation of a 6,000-foot temporary bypass pipeline to provide uninterrupted sewer service to 20,000 residents and businesses in Marblehead during the replacement of the pipeline.
The temporary bypass pipeline allowed removal of the existing pipes in nearshore areas, and the connection of the bypass was made “live” using a wet tap into existing sewer.
The WSP team had to anticipate and take on technical and permitting challenges through design and construction to deliver a high-quality project on schedule and within budget.
Barnett was glad that he and his team were able to contribute to the success of the Marblehead project.
“Rachel, Scott and I have been involved in infrastructure projects that protect and improve the environment for over 25 years,” he said. “This project was very much a continuation of this.”
“It was very satisfying to have that sense of ownership from inception through completion – to see the original concept reach its fruition,” Burckardt added. “Receiving the ACEC National Recognition Award is a recognition of the partnership between the South Essex Sewerage District engineers and our team. Together, we started with a near environmental disaster, analyzed the situation, developed a solution, and then executed this highly successful and innovative project.”
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