July 24, 2008
Mr. Jay Rourke, Senior Project Manager
Boston Redevelopment Authority
One City Hall Square
Boston, MA 02201-1007
Subject: 350 Boylston Street
Dear Mr. Rourke:
Thank you for the opportunity to comment on the Draft Project Impact Report for 350 Boylston Street. The Boston Groundwater Trust was established by the Boston City Council to monitor groundwater levels in the area of the City where the integrity of building foundations is threatened by low groundwater levels and to make recommendations for solving the problem. Therefore, my comments are limited to groundwater related issues.
I am pleased with the responsiveness of the proponent to the groundwater related issues that were raised during the PNF process and the subsequent scoping session for the DPIR. The proponent has confirmed that their recharge system will be 110% of the size required by Article 32 for projects located in the Groundwater Conservation Overlay District so that it can recharge not only rainwater that falls on the roof but any seepage removed by the underdrain system. They have also confirmed that the recharge system will be put into operation before the excavation for the garage and will recharge the effluent from dewatering during the excavation process.
The proponent has also confirmed that the below ground portions of the project will be waterproofed and that they will use a slurry wall system installed from the ground surface and sealed into the relatively impervious clay. This type of construction is designed so that there can be no path along the wall from the critical upper aquifer through the impervious layer to draw down groundwater levels.
I am also pleased that the proponent has installed a groundwater observation well in Providence Street that will be turned over to the Trust for incorporation into the observation well network after construction. The proponent has committed to monitor groundwater levels from this and other wells before and during construction and to report the results to the Authority and the Trust soon after the data is gathered.
I am pleased, as well, that the proponent has committed that "Performance criteria will be established for protection of groundwater levels in the vicinity of the Project. The contractor will be required to modify construction methods and take necessary steps during the work to not lower groundwater levels outside the limits of the site."
I look forward to continuing to work with the proponent and the Authority to assure that this project can have only positive impacts on groundwater levels in the area.
Very truly yours,
Elliott Laffer
Executive Director
Cc: Kathleen Pederson, BRA
Maura Zlody, BED
