The site’s complex, conflicting grade changes drove design decisions too, out of which the team developed a chain of bioswales—they call them a “treatment train”—to direct water into the roundabout. Whereas a concrete roundabout would have presented enormous runoff issues, Greenmeme’s design, developed in collaboration with the ecologist and designer Brent Bucknum of Hyphae Design Laboratory in Oakland, California, conveys half the runoff from the overhead Riverside Bridge, as well as surrounding streets, including busy thoroughfares such as Figueroa Street and San Fernando Road. Overflow is directed to the Los Angeles River. “If you want to revitalize the L.A. River, you have to regenerate upstream interventions as well,” Bucknum says. “The roundabout does that.”