The aqueduct was designed by civil engineer Thomas Telford[1] for the Ellesmere Canal. The resident engineer was M. Davidson who also acted as resident engineer on a number of Telford's other works.[1] The foundation stone was laid on 17 June 1796 and it was completed in 1801.[2] It has a cast iron trough within which the water is contained. The masonry walls hide the cast iron interior. The aqueduct followed Telford's innovative Longdon-on-Tern Aqueduct on the Shrewsbury Canal, and was a forerunner of the Pontcysyllte Aqueduct, also on the Llangollen Canal.[3] The aqueduct was briefly the tallest navigable one ever built, and it now is Grade II* listed in both England and Wales.[4][5] It forms part of the Pontcysyllte Aqueduct World Heritage Site.[5]
Description
The aqueduct consists of ten arches, each with a span of 40 feet (12 m). The water level is 65 feet (20 m) above the ground and 70 feet (21 m) above the River Ceiriog.[2] The stone work is yellow sandstone.[5]William Hazledine provided the ironwork for the aqueduct.[6] Originally built with iron plates only at the base of the trough, iron side plates were added to the aqueduct in 1870 to alleviate leakage.[7][8]
The Chirk Tunnel starts at the north end of the Chirk Aqueduct, allowing the canal to continue on towards Llangollen.[5]Chirk Railway Viaduct was built later alongside the aqueduct. It is slightly higher than the aqueduct.[8]
As is true for the entire Llangollen Canal, a steady current flows in the aqueduct with the narrow cross-section of the aqueduct's trough amplifying this flow.