Narrowboat crossing the World Heritage Pontcysyllte Aqueduct in Wales

Navigable aqueducts (sometimes called navigable water bridges or canal bridges) are bridge structures that carry navigable waterway canals over other rivers, valleys, railways or roads. They are primarily distinguished by their size. They carry a larger cross-section of water than most water-supply aqueducts. Roman aqueducts were created in ancient Rome. They were used to transport water. The 662-metre (2,172ft) long steel Briare aqueduct carrying the Canal latéral à la Loire over the River Loire was built in 1896. It was ranked as the longest navigable aqueduct in the world for more than a century. In the early 21st century, the Magdeburg Water Bridge in Germany was constructed, which became the new longest navigable aqueduct in the world.

Early aqueducts such as the three on the Canal du Midi had stone or brick arches. The longest span was 18.3 metres (60ft) on the Cesse Aqueduct, built in 1690. But, the weight of the construction to support the trough with the clay or other lining to make it waterproof made these structures clumsy. In 1796 Longdon-on-Tern Aqueduct, the first large cast iron aqueduct was built by Thomas Telford at Longdon-on-Tern on the Shrewsbury Canal. It has a total length of 57 metres (187ft) across three intermediate piers. Within ten years, Telford had completed the Pontcysyllte Aqueduct in Wales on the Llangollen Canal over the River Dee valley, with a total length of 307 metres, and a height of 38 metres. This made it the tallest navigable aqueduct in the world. Other cast-iron aqueducts followed, such as the single-span Stanley Ferry Aqueduct on the Calder and Hebble Navigation in 1839, with its 50-metre (160ft) through arch design.

There were 32 navigable aqueducts on the Erie Canal, constructed 1817–1825 in New York State, United States.

Notable [ according to whom? ] navigable aqueducts

Out-of-use cast-iron Longdon-on-Tern Aqueduct
The Magdeburg Water Bridge seen from the shores of the Elbe

Gallery

  • Passenger (packet) boat on the Monocacy Aqueduct of the Chesapeake and Ohio Canal
  • The wall of the Conococheague Creek aqueduct collapsed when a boat hit it, shutting down navigation until repaired.
  • The captain jumped off the boat before the wall went out, dumping the boat into the creek below. There were no casualties in this accident.
  • The Seneca Aqueduct was a lift lock as well as an aqueduct.
  • This wooden aqueduct carried the Morris Canal over the Pompton River.

See also