Locks on the D&R Canal

The Delaware and Raritan Canal was engineered as a series of flat water levels connected by locks so boats could move through a waterway with a constant depth despite natural changes in elevation. Lift locks held back water, adjusted for changes in the land, and raised or lowered boats between levels by closing the gates, changing the water level inside the lock, and then reopening the gates; for upstream travel, the process was reversed. Bypass channels carried canal water downstream when locks were in use. Outer locks, which were not true lift locks, connected the canal with a river or other body of water and accommodated changing water levels or tides; on the Delaware and Raritan Canal, outlet locks were at Bordentown, New Brunswick, and Lambertville. Guard locks, used in infrequently traveled areas, had one pair of miter gates and worked with another structure to regulate downstream water, protect the canal from floods, and allow occasional boat passage; on this canal they were at Bulls Island and Prallsville. Water entered the Feeder Canal at Bulls Island about 67 feet above sea level, dropped to about 55.7 feet at Lambertville lock, and stayed at that level to the Main Canal at Trenton. From that summit, the Main Canal descended through seven locks toward near sea level at Bordentown and through seven more toward near sea level at New Brunswick, while the section defined by Lambertville Lock, Lock 7 in Trenton, and Lock 8 in Kingston served as a reservoir for the Main Canal. The canal used miter gates, which were vertically hinged in pairs to form a V-shape and opened upstream with balance beams, and drop gates, which were hinged at the bottom, placed at the upstream end of a lock, and lowered to the canal floor, usually by chain and wheel. Constructed from 1831 to 1834 with 15 lift locks and 2 guard locks, the canal later saw changes including a replacement Bordentown lock in 1847 to 1848 after the original sank, an outlet lock at Lambertville in 1848 for a cable ferry that operated until 1912 to 1913, conversion of head gates to drop gates in 1849, lengthening of Main Canal locks in 1853, addition of a second lock at New Brunswick in 1866, cessation of canal operations in 1932, filling of the Trenton section in 1936, creation of Delaware and Raritan Canal State Park in 1974, destruction of more than a mile near New Brunswick in 1980 for New Jersey Highway 18, and restoration of the last mile and Lock 14 in 1998 as part of Boyd Park in New Brunswick.

South Bound Brook, New Jersey · United States