Commonwealth Wind collecting soil borings around Barnstable as permitting process gets under way 

Workers are collecting soil borings in Barnstable as part of Avangrid Renewables LLC’s proposed Commonwealth Wind project to develop an offshore wind farm south of Martha’s Vineyard and to land transmission cables at Dowses Beach.

The geotechnical onshore survey work is taking place in Osterville, Centerville, Marstons Mills and West Barnstable, and is projected to continue through Dec. 16.

“Commonwealth Wind has been undertaking geotechnical surveys via soil borings off Dowses beach, in the Dowses Beach parking lot and within potential public roadways in the town of Barnstable that could host the underground concrete duct bank for offshore wind electricity transmission,” Avangrid spokesman Craig Gilvarg said.

Duct banks provide protection for electric and data cable run underground, usually encasing a conduit housing the cables within a duct of reinforced concrete. Borings are taken beneath the ground or seafloor to determine geological features such as sand, soil and rock type mix. The borings help to determine the viability of installing a duct bank and cable system under public roadways, Gilvarg said.

“This data informs preliminary engineering plans and preliminary permitting documents for the Commonwealth Wind project,” he said. “Similar nearshore geotechnical surveys were conducted for Vineyard Wind 1 off of Covell’s Beach in July 2019, for Park City Wind off of Craigville Beach in May of 2021, and for Commonwealth Wind off of Dowses Beach in May and June of 2022.”

Onshore geotechnical surveys were also conducted within roadways in Centerville and Hyannis in 2019 and 2021.

Oregon-based Avangrid Renewables is a division of Avangrid Inc., which is part of the Spain-based Iberdrola SA Group. On Cape Cod, a single truck moves to each of the 19 sampling locations, taking three to four hours to complete each soil boring. The locations include several divided between two potential routes for the transmission lines to follow from Dowses Beach to a substation in West Barnstable should the project complete its permitting.

The “Main Street route” would wend its way along the Dowses Beach causeway to East Bay Road or Wianno Avenue, then Main Street, Osterville/West

Barnstable Road, Old Falmouth Road, Old Stage Road, Oak Street and Service Road. The “Old Mill Road route” would go from the causeway to East Bay Road, Old Mill Road, Bumps River Road, and Lumbert Mill Road to converge with the Main Street route at Old Falmouth Road Avangrid plans to present both routes as possibilities as the permitting process gets started.

The Main Street route would ultimately be more beneficial to the town because the town plans to install a sewer line under Main Street “to address a significant degradation in water quality in Osterville estuaries, including Three Bays, which is among the most threatened water bodies on Cape Cod,” according to the town’s Comprehensive Wastewater Management Plan, No such plans exist for Old Mill Road. By piggybacking on the Commonwealth Wind duct bank work, the town could save millions on the cost of road opening and repaving that could be completed at Avangrid’s expense instead.

Similar tandem work is being done as part of the ongoing Vineyard Wind project, which is bringing an offshore wind power cable ashore at Covell Beach. That project, of which Avangrid owns a 50% interest, the company is also replacing thousands of feet of water mains. The Commonwealth Wind project could potentially provide the same benefit under Osterville’s Main Street, where the water mains are more than 90 years old.

Soil borings begin

Avangrid began collecting soil borings in November, but paused the work last week because of the holiday. Soil borings locations include the following: In Osterville — Dowses Beach parking lot and causeway, East Bay Road near the boat ramps, Wianno Avenue just north of its intersection with East Bay Road and just south of its intersection with Bates Street, Main Street just south of the fire station and just north of its intersection with Admirals Lane, Old Mill Road, south of its intersection with Josh Lumbert Road and just north of its intersection with Swift Avenue, Five Corners Road, south of its intersection with Lumbert Mill Road, West Barnstable Road just north of its intersection with Bumps River Road and just north of its intersection with Pennycress Drive, and Lumbert Mill Road near its intersection with Nye Road and near its intersection with Ensign Road.

In Marstons Mills — Old Falmouth Road just south of its intersection with Fairhaven Lane and near its intersection with Steere Way.

In West Barnstable — Oak Street near its intersection with Sesame Street and near its intersection with Allan Road, and Service Road just west of its intersection with Oak Street.

Mixed reaction from residents

Avangrid is considering Dowses Beach to land three power cables from its Commonwealth Wind project, one of several commercial-scale, offshore wind projects looking to harness the winds south of Martha’s Vineyard. Barnstable is also the landing location for Vineyard Wind at Covell Beach and Avangrid’s Park City Wind at Craigville Beach.

The proposed 1,232 megawatt Commonwealth Wind project, the largest of the three, is just starting the permitting process, having recently filed an environmental notification form to begin a formal review. A number of residents are actively opposing the proposed landing at Dowses Beach.

Although they support sustainable energy and offshore wind in general, the residents said the estuarine environment at Dowses is too fragile for such a large project. They formed an ad hoc community group called Save Greater Dowses Beach, and circulated a petition, both on paper and online via Change.org, to stop the company’s proposed plans for the beach.

A Gofundme campaign is also underway to help the group hire its own environmental expert, and to pay for an attorney if necessary.

Susanne Conley, one of the leaders of the Save Greater Dowses Beach group, said they’ve collected more than 1,000 signatures, and hope to reach 2,000 by the end of December.

“This is going to be a long, drawn-out fight over the next year and maybe longer,” she wrote in an email.

But not everyone feels the same as the Save Greater Dowses Beach group.

Anca Vlasopolos, a self-described birder and environmentalist who lives in Osterville, said while she would feel “bereft of access to the beach” during the installation of cables, “I fully understand the longterm damage done to all life by our continued use of fossil-fuel energy.”

And though associated roadwork would be an inconvenience, and there are concerns about the temporary impact it might have on businesses, there are residents who feel the pluses outweigh the minuses and are very supportive of the project’s potential for bringing sewerage along Main Street and, ultimately, addressing degradation the beach and estuarine system are already experiencing, she said.

People would be able to access Dowses Beach and its parking lot year-round, “with the exception of a 4to 6-week period in the winter” when the company would be installing the duct bank underneath the East Bay Road causeway, according to Avangrid’s FAQ sheet about the project.

Also, the beach will not be dug up. Instead, engineers would employ trenchless horizontal directional drilling with conduit installation beginning from the parking lot and tunneling under the beach at a depth of about 50 feet at the tideline, to about 1,000 feet offshore — just under a quarter of a mile, Avangrid said.

“This minimizes disturbance to the beach or the nearshore area,” the company said.

During installation, according to Avangrid, two portions of the Dowses Beach parking lot would be temporarily fenced off and excavated in phases “to install the transition vaults underneath the parking lot and install the cable casing pipe deep under the beach.”