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Historic Resources: Not Just Static—Boston’s Longstanding Groundwater Issues

HRC JAN 2022

Boston Groundwater Trust (BGwT)

  • COST

    Free and open to the public.

  • TYPE

    Knowledge Community



In January, the HRC welcomes Christian Simonelli, Executive Director of the Boston Groundwater Trust, to discuss with us Boston’s groundwater and wood piling problems which, in truth, go back to the geography that defines our city. The original town was located on the Shawmut Peninsula, a relatively small near-island connected to the Roxbury mainland by a narrow neck, located along present day Washington Street near where it crosses the present-day Mass Turnpike, that was barely a block wide and often flooded at high tide. The Charles Street edge of the Boston Common and Beacon Hill was waterfront property, as was the Congress Street area behind the present City Hall. As the town grew into the thriving City of Boston, it became increasingly crowded and needed space to grow. Entire neighborhoods were created by making new land along tidal flats and in marshy areas but the filled areas could not support heavy structures. Before about 1920, the only way to build substantial buildings in these areas was to support them on wood pilings driven to a level where the underlying ground was strong enough to carry the weight; a typical row house might require 100 pilings, and Trinity Church is supported on almost 5000 of the inverted tree trunks.
In Europe, it had been known for centuries that keeping pilings submerged in groundwater protected them from rot and (even though the mechanism was not fully understood at the time) that dropping groundwater levels could lead to building settlement and ultimate collapse. Although Boston architects and builders generally kept piling caps low enough to keep them submerged, subsequent infrastructure like sewers, tunnels, and below-ground garages inevitably caused leaks that could draw groundwater away and blockages that could impede the underground flow. At the same time, paving for streets, alleys and sidewalks reduced the flow of rainwater that could replenish the aquifer, and storm drains directed the water into the river and harbor. Over time, groundwater levels dropped in many areas. Established by the Boston City Council in 1986, the Trust finally took shape as an active, collaborative institution in 1997. The Trust’s efforts to protect Boston’s legacy of nationally significant buildings and neighborhoods currently focus on maintaining the commitment to monitoring, problem-solving and cooperation.
Christian Simonelli holds a degree in Environmental Engineering from Wentworth Institute of Technology. Hired by the Trust in 1999 as a Field Engineer, Mr. Simonelli was promoted in 2002 to Technical & Recharge Coordinator; in this role, he established the layout and supervised the installation of over 600 observation wells, performed groundwater level readings for every well located in the Trust’s observation well network, advocated for groundwater recharge in all the areas of the City with wood pile supported structures, and acquired information about buildings, infrastructure, and soil conditions to obtain a better understanding of the ground water issue in Boston. Mr. Simonelli was appointed Executive Director in 2014 and runs the day-to-day operations of the organization.