Transbay Transit Center

Transbay Transit Center

Transit Hub Public Rooftop Park

The Transbay Transit Center, located in downtown San Francisco, will centralize the region’s transportation network by housing eleven transportation systems under one roof, connecting eight counties and the state of California. Above this public transportation hub, a 5.4-acre living roof will provide a much-needed public park for downtown residents.  The project encompasses a large-scale integrated water management system that treats combined graywater and stormwater to high standards using biological, mechanical and chemical water treatment systems. At the rooftop park, a subsurface constructed wetland performs polishing treatment of graywater. The subsurface wetland, also called the Water Reuse Garden, presents a unique opportunity for public education and engagement while creating a rich and diverse habitat island within the dense urban landscape.  At the end of conveyance, storage filtering and treatment processes, the graywater will be reused for toilet flushing. The total water related savings are estimated at almost $50,000 per year, given the reduced demand for freshwater on-site as well as reduced stormwater runoff. As designed, stormwater and graywater reuse saves approximately 2.85 million gallons of potable water from being used and discharged into the storm drains annually. This $4 billion project will serve as a model for future developments in California that strive to conserve valuable natural resources and reduce negative impacts to the San Francisco Bay watershed.  California ecosystems were referenced to determine which habitats were applicable to the Transit Center roof. By fostering a strong connection to local ecosystems, ecological design strategies will help create a unique sense of place and provide educational opportunities for visitors as well as residents of the San Francisco community.




Transbay Joint Powers Authority


San Francisco, CA


Pelli Clark Pelli Architects, Adamson Associates, ARUP, Peter Walker + Partners, BVM Engineering, Inc., Flack + Kurtz, Thornton Tomasetti, Atelier Ten, Henshell + Buccellato, Green Building Consultants