Washington, D.C., has ambitious plans to turn the sullied Anacostia River into a showcase along the lines of its better-known counterpart, the Potomac. Could be great for the city, but what about the low-income residents who live along the river now? As restoration and redevelopment get under way in a long-neglected area of the city, some locals and activists worry that a spruced-up Anacostia will leave them without a place to call home. Ethan Goffman explains the dilemma.