Lledan Brook Aqueduct and Weir

The Lledan Brook Aqueduct and Weir is a notable structure associated with the Montgomeryshire Canal, which was built between 1794 and 1797. The original aqueduct at this location was replaced in 1836 by J.A.S. Sword, the canal company's engineer since 1833. Its design was inspired by an earlier aqueduct constructed by George Buck at Brithdir in 1819.

The aqueduct features a base and sides made from a series of bolted cast-iron plates, with paths supported by brick arches. These arches are designed with conventional segmental shapes and rusticated stone voussoirs. Above the western arch, there is an inscribed tablet that reads 'J. Sword, Engineer, 1836'. The tow-path side is topped with cast-iron railings that have a trellised decoration, set between panelled ashlar terminal piers that have domed caps.

On the western side of the aqueduct, brick retaining walls line both banks of the brook, framing a pool beneath a circular weir. This weir was likely rebuilt alongside the aqueduct in 1836 and was used to divert water to the Domen cornmill.

The aqueduct is an excellent example of the engineering related to the Montgomeryshire Canal, showcasing both its engineering significance and architectural character. Together with the weir, it is an important part of a group of structures located at the major canal wharf in Welshpool.