Boston's lack of groundwater threatens foundations
Cristina Kumka
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Owning property in Boston's most elite neighborhoods can be a dream come true....or a complete nightmare. It seems that a lack of groundwater is contributing to the silent deterioration of some of the oldest properties in the Back Bay, Beacon Hill, the South End and Chinatown.
Brian Perry, a Beacon Street guesthouse manager, said the danger lurking under his century-old property is not going away. He said the issue needs to be made more public. "That one issue may affect Back Bay the most...it may not be this year or in ten years...but that particular issue [groundwater] is the most important," Perry said.
Groundwater is essential in stabilizing the foundations of Boston's historic buildings. But a lack of it has been plaguing homeowners and the city for decades.
A new study released by the Boston Groundwater Trust, an organization composed of engineers and other specialists, said that as much as 70 percent of landfill in Boston isn't stable enough to support a building's wood pilings from deteriorating.
 Media Credit: Cristina Kumka The Trinity Church was once threatened by sinking groundwater levels. |
In the past two centuries, many residences and monuments such as the Trinity Church and the Boston Public Library, were constructed atop wood pilings driven into the ground as their foundations. These pilings, which were to last 1000 years if immersed in water, remained stable enough to support the buildings until water table in many of Boston's neighborhoods dropped and exposed the pilings to air and eventually to wood bacteria, fungi and rot. Walls started cracking, beams became weak, and property owners were faced with the daunting and costly task of replacing their foundations.
The change in groundwater levels in neighborhoods around the city is due to obstructions or blocks in the natural flow of water such as construction projects or developed land. Tunnels, highways, and other signs of urban development impeded the natural flow of water, hindering it from seeping back into the ground. After World War II, Boston went through a depression that lasted until the early '60s, where some city development ceased. However, the massive construction projects that followed changed Boston's landscape and its groundwater level.
"The Boston Public Library was affected...it was actually the first big building to have a problem," said Elliot Laffer, executive director of the Boston Groundwater Trust. In 1929, soon after inspectors discovered that the library was in structural danger due to rotting wood pilings, the process of underpinning began. The rotting, bacteria ridden pilings were cut down and replaced with metal and concrete.
 Media Credit: Cristina Kumka Elliott Laffer, executive director of the Boston Groundwater Ttrust |
But unfortunately many property owners in the South End, Back Bay and Chinatown could not afford such a massive reconstruction. According to an article in the Back Bay Courant, four buildings in Chinatown were torn down in the 1980s due to foundation problems that could be blamed on rotting pilings.
The financial burden has proven to be too heavy for many small property owners. The price of fixing their foundations through underpinning as they did with the Boston Public Library is too high; often costing much more than what they initially paid for the property. "I would imagine the cost to be in upwards of a quarter of a million dollars," Perry said.
The problem started raising eyebrows in the 1980s when water levels became severely low. City councilors and neighborhood activists demanded that the city take action and a municipal trust was established in 1986 called the Boston Groundwater Trust. After falling inactive, Mayor Thomas M. Menino reactivated the Trust and funds from the state and local government flowed. The state has donated approximately $1.6m and the city has funded such projects as the installation of wells to keep track of the rise and fall of water levels throughout the city. Laffer said the Trust hopes to have installed 800 monitoring wells by the end of this year.
 Media Credit: Boston Public Library The Boston Public Library |
Laffer said it is hard to tell how many buildings are being affected because many property owners don't know they have a problem or if they do they aren't coming forward. "So far as we know, insurance doesn't pay for it," he said.
Laffer said the key to balancing the water table under one's property is to fix any leaks, not pump the excess water to the surface. The water may not have another chance to soak back down into the ground and wood pilings, he said. Homeowners could install dry wells to collect rainwater drainage from their roofs and redirect the water underground. Laffer said making neighbors aware is also key in preventing the disappearance of groundwater. Using a pump can lower the water table under all surrounding properties and affect everyone.