In 1817, the Erie Canal was established under the management of the Erie Canal Commission, dug from Albany to Buffalo 4’ deep and 40’ wide with stone locks 15’ x 90’, and its success led to additional canals and a statewide network built to similar dimensions. In 1836, an enlargement program on the main Erie Canal straightened the canal, increased the channel to 7’ x 70’, and enlarged the locks to 18’ x 110’, allowing much larger boats on the Erie, Champlain, Cayuga-Seneca, and Oswego canals. To compete with the railroad, work began on a twentieth century canal with cast concrete structures and electric controls, and the Barge Canal System, using canalized rivers and lakes and enlarged sections of the Erie Canal, opened in 1918. Operating today as the New York State Canal System, it continued to use several old routes and, on January 11, 2017, was listed as a National Historic Landmark made up of the Erie, Champlain, Oswego, and Cayuga-Seneca canals. Spanning 450 miles, these waterways link the Atlantic Ocean to the Hudson River, Mohawk River, Lake Champlain, Lake Ontario, the Finger Lakes, Niagara River, and Lake Erie, and the system is owned and operated by the New York State Canal Coporation, a sub-agency if the New York Power Authority. Just north of this location, the first English settler, Edward Rexford, bought 300 acres that became known as Rexford Flats, and William Alexander built the first bridge here in 1804. In 1825, the first aqueduct, the Upper Mohawk, was constructed west of the Rexford Aqueduct. The Rexford Aqueduct was built in 1841-1842 as part of the Erie Canal to carry vessels over the Mohawk River. Its center section was removed in 1914 for the Barge Canal, and the center span was replaced by a small bridge so the towpath could continue in use and new barge traffic could move through the canal. When the Warren Truss Bridge was built in 1964, most of the aqueduct was dismantled, but three of the original fourteen arches were preserved in place, one at the north end in Rexford and two at the south end in Niskayuna. In 1969, the Rexford Aqueduct was documented in the Library of Congress as Historic American Engineering Record #12. In 2017, a multi-girder four span bridge was built just west of the 1964 Warren Truss Bridge, with construction carefully avoiding and protecting the aqueduct and the remains of the Erie Canal. One northern pier of the 1964 truss bridge was left in place to shield the aqueduct remains from ice jams, the bridge replacement project added a roundabout to ease congestion at the southern end, and a new multi-use path over the bridge provides a pedestrian and cyclist connection from the Mohawk-Hudson Bike-Hike Trail in the Town of Niskayuna to the Town of Clifton Park.
