Canal Drain to W of embanked Aqueduct

This dry dock and associated canal drain were constructed in 1805 as part of the Brecknock and Abergavenny Canal, under the direction of Thomas Cartwright. The dry dock, a rectangular structure situated west of the embanked aqueduct, was designed to be sealed off from the canal using stop planks, allowing water to drain into a stream via a trapezoidal-shaped sluice to the east. These two features are connected by a low bank built of rubble. The dry dock has undergone repairs, including a concrete facing. A footbridge spans the sluice, and both the dock and the sluice are controlled by two surviving rack-and-pinion paddles. Historically, a windlass also operated a drain plug within the canal. A parapet continues as a low rubble wall beyond the sluice.

The Brecknock and Abergavenny Canal, promoted in 1792 to connect the upper Usk valley to the Monmouthshire Canal, underwent construction stages between 1797 and 1812, with different engineers involved. The canal facilitated trade in iron, lime, and coal, linked to tramroads, and was eventually absorbed into the Monmouthshire and Brecon Canal Company in 1865. Later, it was purchased by the Great Western Railway before being abandoned in 1962. Restoration work commenced in 1964 and continues today. The dry dock and canal drain are included on the list for their group value alongside the embanked aqueduct and other canal structures, representing a significant surviving element of this early 19th-century canal network.