Regular visitors to D.C.’s Shaw-Howard University Metro Station will be familiar with the water. Year-round, a soft trickling sound can be heard in the damp station, and sometimes the water visibly flows over the southbound rail bed. In the photo to the right, the flow has slowed leaving a series of puddles. Although the station is much newer than most others in the system (it opened in 1991), the cement walls are stained with algae and mineral residue left by water. The picture above shows a valve installed directly into the wall to drain water from behind the cement.
All the water is partly due to the station’s construction. It was built just beneath the road surface through a cut-and-cover technique where a hole is excavated and then a roof constructed to create a tunnel. Although the much deeper stations like Dupont Circle also have water problems, they were constructed by drilling directly into bedrock and thus insulated somewhat from subsurface flow. Shaw’s water might have another cause: it is barely one block from a historical stream noteworthy enough to be one of two named streams on eary versions of the L’Enfant Plan.
Labeled “Reedy Branch,” early maps show the stream flowing east from 7th and S st NW in Shaw to join Tiber Creek, and then flowing south just east of North Capitol Street to the Mall. Another version of the L’Enfant plan drawn by Andrew Ellicott in 1792, and shown below, adds the note to the Reedy Branch that “This branch of the Tiber may be conveyed to the Presidents house,” suggesting it is possible the water in the Shaw Station — just south of the natural riverbed — could indeed be the stream.
H-DC has a good listing of D.C.-specific online mapping resources