Tiber Creek, first known in the original Maryland cession as Goose Creek, flowed from a headwaters near Petworth and along the present-day National Mall before discharging into the Potomac near the site of the Washington Monument. Originally lined with tulip poplar, magnolia, and wild azalea, the low-lying watercourse was rationalized into a barge canal that reached almost to the site of the Capitol as the area faced increased urbanization.
The architect Benjamin Henry Latrobe, who was at work on the Navy Yard when the canal was first proposed, contributed to the design that would transform the Tiber into a working canal. When thinking about the design, Latrobe noted that flat-bottomed Potomac boats had no problem navigating the river at Georgetown and above, but struggled in the more open water below the confluence of Rock Creek. He also observed that larger, oceangoing vessels had trouble navigating as far upriver as the Georgetown docks. His solution, a canal that allowed the smaller vessels to reach the "Eastern Branch" or Anacostia River, would extend the zone of commerce, becoming a place where import and export craft could meet. Latrobe himself supervised the crews of Irish workers that dug the canal and closely watched the construction of the locks.
However, the soil of the old Tiber Creek was notoriously unstable, and soon after the canal's construction the structure began to decay and fall into disuse. Before long, the canal's prism in effect turned into an open sewer and became a hazard at night for mules and for inebriated people who left taverns on Pennsylvania Avenue. Declared unsanitary, city officials cited problems with typhoid and other diseases when calling for the eventual filling in of this waterway.