Stata Center Underground Detention image courtesy of Judith Nitsch

Stata Center Underground Detention image courtesy of Judith Nitsch

Article taken from The Environment at MIT

MIT has constructed the Stata Center, a major research facility designed by Frank Gehry. The site of the Stata Center is urbanized, and is located at the site of former Building No. 20 (razed in 1999). Prior to the commencement of construction activities, site conditions directed stormwater from the site into storm drainage pipes that connected to the City of Cambridge’s combined drainage/ sanitary sewers located in Vassar and Main Streets. Ultimately, the water flowed to the MWRA treatment plant or, during heavy flows, into the Charles River itself. The Vassar/Main Street intersection is prone to flooding, especially during severe storm events.

MIT now mitigates stormwater runoff from the renovated site by an innovative, state-of-the art (for an urban area) stormwater control and treatment system. Approximately one half of the Stata Center site is drained to a “biofiltration” swale located between Buildings No. 57 and 56. The biofiltration swale is constructed with soils and vegetated with plant species designed to provide natural biofiltration. The plant species employed are capable of filtering oil and grease as well as suspended solids from stormwater. Runoff entering this swale filters through the vegetation and is detained below grade in a galley chamber.

Original system plans identified the galley chamber as a system of 3 interconnected 48-inch pipes, however, new technologies were adopted that perform the same task more efficiently. Rather than the 3 tube system, a high-density, recycled plastic, lattice work system (rainstor) was installed to contain runoff water.

The rainstor is capable of holding the same volume of water (50,000 gallons)as the pipe system but with a much smaller footprint. This resulted in less excavation required and less impact on surrounding infrastructure systems. Outflow from the galley chamber is discharged at a controlled and reduced rate of flow by an effluent stormwater pumping station via a force main into the Vassar Street storm drain line, which will connect to the new stormdrain being constructed beneath Massachusetts Avenue.

Based on hydrologic modeling, this process will yield a 50% or more reduction in the peak stormwater flow rate compared to pre-development levels, and will achieve improved Total Suspended Solids removal from the runoff as well. The system is designed to achieve an 80 percent reduction in Total Suspended Solids. Finally, as presently constructed, the stormwater collection system also serves as a rainwater harvester – collecting rainwater, storing it, and reusing it within the Stata building for flushingwater.  The collected rainwater supplements the potable city water for all toilet-flushing activities.  It is estimated that the Stata building will consume approximately 5,000 gallons per day for flushing water, suggesting that the stormwater collection/ rainwater harvesting system will yield a discharge to the Vassar Street storm drain line.