June 15, 2010
Mr. Ian A. Bowles, Jr., Secretary
Executive Office of Energy and Environmental Affairs
Attn: MEPA Office - Aisling Eglington
EOEEA #14597
100 Cambridge St., Suite 900
Boston, MA 02114
Subject: Liberty Mutual, 157 Berkeley Street
Dear Secretary Bowles:
Thank you for the opportunity to comment on the Environmental Notification Form for 157 Berkeley Street. The Boston Groundwater Trust was established by the Boston City Council to monitor groundwater levels in sections 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 was pleased that the proponent and his consultants met with me to discuss their plans for addressing potential groundwater related issues before filing the ENF. I appreciate their acknowledgement of the importance of the issue and the careful plans that they laid out to prevent reduction of groundwater levels in the area. The project will include a four level underground parking/mechanical space, so care must be taken to assure that it cannot cause a groundwater drawdown. This is especially true because the project is located in an area in which our existing monitoring wells indicate a history of low groundwater levels, and, as noted in the ENF, there are nearby buildings supported on wood pilings.
The project will, according to the ENF, include a slurry wall or similar system sealed into the underlying impervious clay to prevent groundwater infiltration. While there will be an underdrain pressure relief system, any water captured there will be recirculated into the recharge system and ultimately will be recharged into the shallow water table that is critical for preservation of wood pilings. Although the best alternative for assuring that there will be no reduction in groundwater levels is to eliminate the underdrain system, the approach outlined in the PNF may be acceptable if properly engineered and installed. The steps to be taken to assure the desired outcome should be included in the required engineer’s stamped report showing how the project will not cause a reduction in groundwater levels on the site or adjacent lots as specified in Article 32 of the Boston Zoning Code.
The recharge system is planned to include a storage tank sized to meet the requirements of the Groundwater Conservation Overlay District and a series of injection wells to recharge the water into the ground. The wells are likely to be on public property because the building will occupy virtually its entire site.
The proponent has committed to provide two new groundwater observation wells on the south side of Columbus Avenue across from the site. I look forward to working with the development team to confirm the site of the wells. I also appreciate the commitment that the proponent will replace the Trust’s well located at the corner of Berkeley Street and Columbus Avenue immediately beyond the site boundaries if the well is damaged during construction.
The project will be seeking designation as a Planned Development Area, and will therefore not go before the Board of Appeals to deal with zoning issues. Therefore, it is critical that the project file its letter detailing no harm to groundwater stamped by a Professional Engineer with the BRA and the Trust, receive its approval letter for the recharge system from the Boston Water and Sewer Commission, and receive any necessary approval for the injection wells from the Public Improvement Commission before zoning is finalized.
I look forward to continuing to work with the proponent to assure that the project can have only positive impacts on groundwater levels in the area.
Very truly yours,
Elliott Laffer
Executive Director
