Watershed, Stormwater, & Integrated Water Management
- Sustainable Design Consultant for:
- MIT Ray & Maria Stata Center Stormwater Management System
Cambridge, Massachusetts
the challenge The Massachusetts Institute of Technology (MIT) in Cambridge hired Frank O. Gehry & Associates to design a new complex dedicated to offices, research institutes, and laboratories for computer, information, and intelligence sciences and to serve as an interdisciplinary incubator for new ideas. When watershed and stormwater management requirements presented major hurdles to approval of the project, The Bioengineering Group was hired to supplement the original consulting team and serve as sustainable design consultant and urban stormwater specialist for evaluation and design of the overall stormwater management and water reuse systems. The goal was to develop a viable stormwater management system that eliminated runoff releases from the site up to the 100-year storm, thus minimizing pollutant loading to the Charles River watershed and overloading of an old and undersized local stormwater handling system.
the interdisciplinary approach The Bioengineering Group evaluated the pre-development water budget for the site to guide selection of a sustainable management strategy, essentially quantifying the portion of the total annual precipitation that had been infiltrated, versus leaving the site through evapotranspiration or runoff. Since the site occupied filled former tidelands with poor infiltration capacity, alternatives to infiltration were prioritized, such as capture, storage, evapotranspiration, and water harvesting for re-use as well as runoff reduction. We identified opportunities for applying green roofs and selecting permeable paver systems for plaza areas, but the top priority emerged as harvesting stormwater runoff for use in toilet flushing and irrigation of landscape plantings.
The Bioengineering Group conducted hydrologic modeling to determine runoff and water quality output, and for an array of alternatives to determine how best to meet the design objectives. A vertical flow wetland over a subterranean storage/detention vault concept proved to be the most cost effective approach to meet multiple objectives. Using the selected treatment option we then generated estimated water quality outputs plus estimates of pollutant-loading reduction. Our team also worked with the engineers and the landscape architects to integrate the system into the site landscape design, prepared concept design documents, and developed specifications for earthwork, soil mixtures, and installation of the photovoltaic pump used to recycle and treat water for toilet flushing in the new building.
the resultsThe final design features a permanently moist biofiltration swale vegetated with a stunning wetland plant community, a visual focal point of an avant garde quadrangle that has won acclaim from facility users and the academic community in general. The thoughtful and creative technologies have become a point of pride for MIT, and are used as curriculum elements in urban design and engineering courses. The additional stormwater harvesting measures were found to have a three-year return on investment, and promise to continue saving money on water bills for decades to come, not to mention conserving water in a region of limited supply. Significantly, the project has raised the bar in the region regarding what it means to manage stormwater runoff “to the fullest extent practicable” and is seen as a key instigator to local municipalities including Cambridge and Boston adopting municipal sustainable design ordinances.