Impacts of Declining Groundwater Levels on Wood-Pile Supported … · 2019-10-25 · Good...
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Impacts of Declining Groundwater Levels on Wood-Pile Supported Historic Buildings in Boston – A Unique Case Study in Urban Groundwater Management (Speaker) Boston Groundwater Trust Haley & Aldrich December 2006
Transcript of Impacts of Declining Groundwater Levels on Wood-Pile Supported … · 2019-10-25 · Good...
Impacts of Declining Groundwater Levels on Wood-Pile Supported Historic Buildings in Boston – A Unique Case Study in Urban Groundwater Management
(Speaker) Boston Groundwater Trust Haley & Aldrich December 2006
From USGS, 2005
From USGS, 2005
Colonial Shoreline
From USGS, 2005
Profile A
10-30 Ft
5-30 Ft
0-25 Ft
40-140 Ft
0-10 Ft
5-30 Ft
Typical Thickness
Timber Piles
Rock Socketed Caisson/Drilled
Shaft
PIFs
Friction Piles
End Bearing
Piles
Belled Caissons
Footings
Groundwater Conditions
Generally shallow (5 ft to 15 ft depth) Deeper in permeable material (sands) Shallow in less permeable material (silts and clays) Gradient is downward (groundwater elevations are
lower with increasing depth)
Wood Piles
Back Bay, Boston
Signs of Foundation Distress
Untreated Wood Piles
Must remain submerged below groundwater levels
Post Timber
Pile
From Aldrich And Lambrechts, 1986
From Aldrich And Lambrechts, 1986
From Aldrich and Lambrechts, 1986
Steps to Address the Problem
Boston Groundwater Trust created in 1986 Political support, funding, led to expansive
monitoring well network Memorandum of Understanding developed among
key stakeholders in the City New Bylaw requirements –
– require recharge – No negative effects on groundwater levels
Most importantly, it has people thinking about ways to correct the problem.
Summary
Historical and modern development has lowered groundwater levels
In filled areas, historic structures founded on wood piles have been damaged or are at risk
Steps taken by the City and BGWT may keep the problem from getting worse
Innovative thinking is still needed to raise water levels in problem areas!
Good references on Boston Groundwater and Wood Piles Seasholes, N.S., 2003, Gaining Ground, A History of
Landmaking in Boston, MIT Press. Aldrich, H.L. and Lambrechts, J.R., 1986, Back Bay
Boston, Part II – Groundwater levels: Civil Engineering Practice, v. 1, no. 2, p. 31-64.
USGS, 2005, Water Resources and the Urban Environment, Lower Charles River Watershed, Massachusetts, 1630-2005, Circular 1280.
Boston Ground Water Trust website – www.bgwt.org
