In February 2019, Boston College began construction of a road salt storage facility on the rear parking lot of the land it owns in Webster Woods.
In November 2018, Boston College filed plans with the City of Newton to construct the salt storage facility. Neither the Newton Conservation Commission nor any other city department had the authority to prevent the construction of this facility. Construction began in February 2019, and was substantially complete by June.
This facility threatens Webster Woods because of the likelihood of runoff of salt-contaminated rainwater from the site, and because of the likelihood that flaws in the parking lot will allow infiltration of salt water into the ground. The “Parking Lot Cores and Stormwater Infiltration Summary” prepared in May 2018 by the engineering firm Haley & Aldrich states the following:
“The thin section of pavement encountered near [test boring sites] PC-1 and PC-4 and the fine-grained subbase could result in pavement cracking and pothole development because of future heavy wheel loading within the pavement footprint. This may require regular maintenance in the future. However, this maintenance may be far less expensive than a full pavement and subbase replacement project and further discussion with the Project Civil Engineer is recommended.” (emphasis added)
In other words, Boston College decided to save money on construction by tolerating a significant risk of salt-water contamination of the soil under the parking lot. And once salt water reaches the soil below the parking lot, it could be carried onto surrounding land, including the vernal pool Bare Pond, which is only 100 feet from the parking lot.
The site plan filed with the city shows that a portion of the parking lot will be used for uncovered snow storage. Another area, in the spot closest to Bare Pond, will be used for “ancillary uncovered storage.” The plans do not indicate whether salt or other materials will be stored in this location.
The plans include measures to control runoff of salt water, including “vertical granite curbing to prevent stormwater runoff overland,” “silt sock/ silt fence erosion-control barrier,” “subsurface infiltration system (infiltrates stormwater with overflow to outlet pipe),” and “overflow flared end section with stone protection to prevent erosion”. The plans do not indicate under what circumstances “overflow” of salt-laden stormwater might be expected to leave the parking lot and flow into the woods.