Gilwern canal embankment

button-theme-canalGilwern canal embankment

gilwern_canal_embankment_drawingHere the Monmouthshire & Brecon Canal crosses the Clydach Gorge on a towering embankment, visible in the drawing by the late Mike Blackmore.

The canal was engineered in the 1790s to parallel the river Usk, largely avoiding expensive infrastructure across valleys, but here the river Clydach had to be crossed. Bridging the gap with a high aqueduct was beyond the technology of the time. Taking the canal down a flight of locks to a low-level aqueduct and back up another flight of locks would have been expensive to build and maintain, and would have consumed water and boat crews’ time.

Engineer Thomas Dadford designed an embankment of rock and earth, c.25 metres high and 100 metres long. It was built in 1797 by contractors Thomas Powell of Abergavenny and William Watkins of Llanvihangel Talyllyn. Today its slopes are thickly wooded.

Benjamin James of Blaenavon built an arch over the river for the embankment to rest on. It is c.90 metres long, as the base of the embankment is much wider than the top.

He also created a tunnel at the north end of the embankment for the Clydach Railroad, which connected Beaufort to Glangrwyne and was also engineered by Thomas Dadford. It was built in 1794. The horse-drawn wagons ran on bar-type rails, with flanges on the wheels to keep the wagons on the track (most other tramroads had flanges along the rails instead). A footpath now runs through the tunnel.

Another wagonway, the Llam-march tramroad, met the canal at a wharf south of the embankment. It was built in 1795 to carry lime and coal from the Llanelly Hill area to Clydach ironworks, and extended in 1803 down the gorge to Gilwern.

Today the navigable section of the Monmouthshire & Brecon Canal is looked after by the charity Glandwr Cymru the Canal & River Trust in Wales.

With thanks to the archive of the Monmouthshire, Brecon and Abergavenny Canals Trust and the family of Mike Blackmore

Postcode: NP7 OEP    View Location Map

Canal & River Trust website – Monmouthshire & Brecon Canal

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