The Boston Architectural College's Green Alley project demonstrates that immediate and long-term environmental challenges facing the City of Boston can be met through creative partnerships between experts and institutions. Its success extends beyond the intelligent beautification of a single area of the campus. It is a replicable design with potentially far-reaching effects.
Below is a real-time display, that shows various environmental conditions through data derived from a monitoring well installed on BAC campus.
Permeable paving allows water to percolate downward into the earth below rather than be conveyed across a paved surface to the Charles River via a conventional storm sewer. Both permeable asphalt and permeable unit paver systems were installed over a large common gravel bed designed to collect, store, and drain rain water from the alley surfaces and two BAC rooftops. Below ground, designers and construction managers on the project had to work around many existing utilities, including the infrastructure of the recently installed geothermal wells. The longer-term vision for the Green Alley effort includes the connection of the geothermal well system to serve the College's core buildings and lead the BAC toward a net zero campus energy goal.
Geothermal wells use the earth's core energy, roughly 55 degrees, to pump water through a series of pipes into a heat pump within the building to heat and cool the building using the earth's core temperature to either inject or reject heat. The earth's core temperature is a renewable resource that is actually solar energy that is stored within the earth's crust. Geothermal energy is a renewable resource that has been deemed most efficient to heat and cool buildings. This renewable resource is similar to solar and wind, and in some NE climates it is actually more efficient because it does not depend on the variable aspects of wind of the sun. The earth's core temperature is stable.
The objectives of the BAC Green Alley Initiative are three-fold: The first is to recharge the groundwater by increasing rainwater infiltration through permeable paving, the second is to clean the rainwater as it enters the watershed, and finally, to create educational outreach to the school and public.
The scope of work for the groundwater recharge entailed removal of the existing paving surface as well as the base material, and the installation of a new paving section that is comprised of a reservoir layer of crushed stone, a filtering layer of well-graded sand and stone, and a permeable paver paving treatment. In addition, the rainwater from the downspouts of surrounding buildings was directed into the reservoir layer to increase the amount of storm water that is allowed to infiltrate into the ground water.
The Green Alley is located on BAC campus in Public Alley 444, in between the College's 951 Boylston Street building and 320 Newbury Street building.