Last updated: January 20, 2024
Article
The Big Dig and Spectacle Island's Environmental Restoration
Boston Globe Photo
When construction on the Central Artery/Tunnel Project (known as "The Big Dig"), began in 1991, the city of Boston undertook one of the largest infrastructure projects in its history. The project had two main goals: to alleviate traffic on an overburdened, elevated highway that had begun deteriorating, and to extend I-90 from south of downtown Boston. To achieve these goals, engineers planned to create an underground highway mostly consisting of tunnels. The project quickly became one of the most expensive and complicated in the world. Construction began in 1991 and finished in 2006, eight years behind schedule. The project cost nearly 15 billion dollars when finished, instead of the projected 2.6 billion.[1]
Once finished, the tunnels did alleviate congestion. Carbon emissions in Boston dropped by 12% because cars were moving instead of idling in traffic.[2] The project also included the Zakim Bridge—which has become an iconic part of the Boston skyline—and the Ted Williams Tunnel, which runs under Boston Harbor and connects Downtown Boston to Logan Airport.
The Big Dig also created 300 acres of green spaces. The Rose Fitzgerald Kennedy Greenway replaced the old highway with its lush vegetation and park spaces. Spectacle Island, Millennium Park, and Memorial Stadium Park received soil from the Big Dig, which excavated more than 16 million cubic yards of soil. Almost a quarter of that dirt went to Spectacle Island. This influx of soil transformed the landscape of the island into what visitors see today.[3]
Long before the Big Dig, Spectacle Island had served as the city dump from 1921 to 1959. The abandoned island produced so much methane gas by the 1960s that underground fires broke out and burned for many years. Selected as a prime candidate for the dirt from the Big Dig, the city shipped barges across the harbor filled with dirt for Spectacle’s “capping” project. This process entailed placing a half-meter clay liner to cap the dump. First capped with the clay, workers then added an additional two to five feet of topsoil on top. The fill changed the topography of the island, making the north drumlin the highest point in the harbor.
NPS Photo
Once capped, planting began. Over the course of 15 years, landscape architect Clarissa Rowe led the planting of more than 2,400 trees and 26,000 shrubs on Spectacle Island. Only shallow-rooted trees were planted, so roots would not pierce the seal over the landfill below. Species were carefully selected in order to restore the island’s natural ecosystem.[4]
NPS Photo
Today, the trees, shrubs, and grasses attract different types of birds, including osprey, mockingbirds, red-tailed hawks, redwing blackbirds, and even turkeys. The flowering plants attract pollinators like bees and butterflies. Small mammals and rodents have returned to the island, and larger mammals like coyotes, deer, and raccoons are also spotted from time to time. The careful restoration of Spectacle Island has not only made it into an attractive recreation area for visitors, but it also restored a diverse ecosystem where wildlife thrives. This amazing feat of environmental reclamation is a testament to hard work, dedication, and a vision for a cleaner future.
Footnotes
[1] Virginia Greiman, "The Big Dig: Learning from a Mega Project," last modified July 15, 2010, The Big Dig: Learning from a Mega Project | APPEL Knowledge Services; "The Big Dig: Project Background," Mass.gov, accessed April 14, 2023, The Big Dig: project background | Mass.gov.
[2] Justine Hofherr, "Can We Talk Rationally About the Big Dig Yet?," last modified January 5, 2015, Can We Talk Rationally About the Big Dig Yet?.
[3] "The Big Dig: Facts and Figures," accessed April 14, 2023, The Big Dig: facts and figures | Mass.gov.
[4] Ashira Morris, "Where Does the Dirt Go?," Silica Mag, May 25, 2020, Silica Mag — Where Does the Dirt Go?; Donna M. Keefe, "Green Line Extension and the Big Dig," accessed April 14, 2023, Spectacle Island | Boston's Big Dig | Historical Fiction.