Posts Tagged by Boston Ground Water Trust

Tonight I attended the meeting of the Trustees of the Boston Groundwater Trust, and learned about their mission to save historic homes and buildings in the city of Boston.

Much of Boston is build on landfill in an area that used to be tidal marsh and mud flats.  In order to construct large multi-story buildings over this type of material, wood pile foundations were constructed. Workers would drive wooden logs through the soft fill and marsh peat until they reached hard clay, some 30 or 40 feet below, which was capable of supporting heavy structures. Buildings were erected this way up through the early part of the 20th century.

This was a sound engineering practice as logs will not rot as long as they are submerged in groundwater, but as Boston modernized it implemented practices that caused the groundwater table to drop.  Dirt and gravel roads and open fields were paved over for car transportation and parking, ensuring that the water that used to infiltrate now ran directly to the Charles River or the ocean.  Municipal and storm water sewers were constructed below the water table, and if they were leaky, water drained from the ground into the pipes, and was quickly transported out to sea.  Tunnels were constructed for trains, cars, and gas and electricity as well, which also served to drain groundwater.  These new technologies drew down the groundwater table below the tops of many wood piles.  Now the top of the logs were exposed to the air and could rot, threatening the integrity of the structure that they were supporting.  Wood piles can be repaired by sending work crews beneath the foundation of a building to replace the rotting wood with concrete and steel, but this process is not cheap.  Furthermore, if water levels continued to drop the issues would just get worse.

In 1986, Boston City Council founded the Boston Ground Water Trust to study and monitor this issue.  In 2005, the City-State Groundwater Working Group was created, an agency that brought together all public agencies with underground tunnels in the City of Boston, to collaborate on raising the groundwater table.  These include the Massachusetts Bay Transit Authority, the Boston Water and Sewer Commission, the Massachusetts Water Resource Authority, and the Massachusetts Department of Transportation.  At the meeting, the trustees said that this working group proceeded with surprising unity, in contrast to the often rancorous political climate in Boston, to save the historic buildings.   The Working Group is sealing tunnels, and in some cases, pumping municipal water directly into the ground.

More information on the Boston Groundwater Trust and the City-State Groundwater Working Group is available at www.bostongroundwater.org.  Maps of well locations and groundwater elevation data can also be downloaded.