C&O Canal Locks 3 & 4 Rehabilitation

The C&O Canal was constructed as America’s first nationally funded infrastructure project between 1828 and 1850. Its most visible piece of engineering are the lift locks. Given the irregular terrain of Georgetown, four locks were built to transfer vessels from one water level to another. For nearly 100 years, this canal operated as an industrial entity until it was damaged in the 1924 Flood and effectively replaced by railroads for transporting coal and other commodities.

McMullan was the SEOR for the rehabilitation of these two stone masonry locks constructed in 1832 and located between 30th and 31st Streets NW. Lock No. 3 required complete reconstruction to address tilting walls due to failure of its timber foundation. The timber lock gates were removed; the 15-foot-high ashlar laid stone masonry walls were disassembled, marked, and temporarily stored; and the timber lock foundation was removed. After a concrete mat foundation was installed, the original lock walls were reconstructed with the stones in their original position. Lock No. 4 required repairs to address water leakage through the masonry and deteriorated timber gates. Repairs included partial replacement of deteriorated stones, repointing, and replacement of the wood lock gates and associated hardware.

After construction of the lock masonry, timber lock gates were installed at the upstream and downstream end of the locks. The gates were tested by loading them with a full height of water and determined to successfully support that load. As a result, these locks are available once more for the Georgetown Canal boat that is operated by the National Park Service in the summer months.

(Above Photo Credits - © Geoff Livingston Photography, National Park Service & JMT)

Awards

• SEAMW Excellence in Structural Engineering Outstanding Specialized (Non-building) Structure Award

CANAL PROJECTS