The Tidal Reservoir of Washington, DC

The confluence of the Anacostia and Potomac Rivers were initially wetlands, but the development of Washington, DC required navigable shipping channels and flooding control. After a major flood in 1881, the Army Corps of Engineers used dredged Potomac River sediment to fill the swampland and build a pond. The Tidal Reservoir, now known as the Tidal Basin, helps control tidal flow and prevent flooding.

In The Hesperus Prophecy, on the night of the Obturavi attack in 1898, Thomas Edison has a boat waiting in the Tidal Reservoir to whisk away the Powell family. Unfortunately, Father doesn’t join them, staying to defend the Library of the Ages and Sanctuary of the Epistolith.

Same view of Washington, DC 150 years apart. The National Mall runs horizontal. In the 1862 map, the Potomac’s shore lies just west of the White House Ellipse. Compare with the modern map’s added green land where the Lincoln Memorial resides and forms the Tidal Basin.