LONGDON-ON-TERN AQUEDUCT 1796 Shropshire Thomas Telford HEW280 SJ617 156 N52o 44’ 8.8” W2o 34’ 6.6” This historic aqueduct is on private land and is well fenced off to discourage curious trespassers. One can glimpse it through a gap in the hedgerow along B5063 about five miles northwest of Wellington.
This was the first canal aqueduct to be made of cast iron. Telford, who had recently been appointed the Shropshire County Engineer, was responsible for completing the aqueduct which had been begun in masonry by his predecessor to carry the Shrewsbury Canal over the River Tern. The trough is three feet deep and nine feet wide, the iron section being 186 feet long. The slim ironwork section on its cast iron supports seems very unsubstantial between those two very substantial arched brick approaches. However, his design has stood the test of time.
It is interesting to note that the concept of creating an iron “box” carrying water supported on diagonal cast iron supports was probably borrowed by Telford from a very original aqueduct/bridge, Pont y Cafnu, designed and built in 1793 by Watkins George, chief engineer at the Cyfarthfa Iron Works. It is known that Shropshire iron master William Reynolds sketched that Pont-y-Cafnau bridge/aqueduct in 1794 and Reynolds worked with Telford to build this Longdon-on-Tern aqueduct in 1795.