Photographs of Froncysyllte Aquaduct

Click on an image to see the full picture

The Froncysyllte Aquaduct is a navigable aqueduct that carries the Llangollen Canal over the valley of the River Dee in Wrexham County Borough in North East Wales. Built by Thomas Telford and completed in 1805, it is the longest and highest aqueduct in Britain. The trough sides rise only about 6 inches (15cm) above the water level, less than the depth of freeboard of an empty narrow boat, so the helmsman of the boat has no visual protection from the impression of being at the edge of an abyss. Every five years the ends of the aqueduct are closed and a plug in one of the highest spans is opened to drain the canal water into the River Dee below, for inspection and maintenance of the trough.