Slower and marshier than the Potomac, the "Eastern Branch," or Anacostia River, suffered greatly under expanding urbanization after the Civil War. Seeing the river as polluted and sluggish, the creators of the McMillan Plan advocated transforming the Anacostia into a large, urban-scale water park to provide city residents with a venue for boating and swimming. The U.S. Army Corps of Engineers made some effort toward dredging and constructed dams to make the area available for recreation, but funding shortages and intervening national crises prevented the fulfillment of the objectives as outlined by the McMillan Plan commissioners.
In the late twentieth century, the government of the District of Columbia spearheaded an effort to coordinate between the various governing agencies and adjacent jurisdictions to restore the Anacostia to a vibrant and clean waterway. Progress has been made, but the river still suffers from its long history of pollution and neglect.