Then and Now - the Brecon Canal

The Monmouthshire & Brecon Canal, known affectionately as the Mon & Brec, began life as two separate canals – the Monmouthshire Canal and the Brecknock & Abergavenny Canal. Although the two were joined in 1812 at Pontymoile, this year’s anniversary celebrates the completion of the more northern Brecon Canal twelve years earlier.

Each month heritage consultant David Viner is taking a look back at how the canal has evolved to become the much loved waterway it is today flowing through the Bannau Brycheiniog National Park, from its construction taking it from Gilwern all the way to Brecon.

Gilwern

In 1793 an Act was passed for the creation of the Brecknock & Abergavenny Canal, running 35-mile (56 km) between Brecon and the Monmouthshire Canal at Pontymoile, with additional powers for the company to build tramroads up to eight miles from the canal.

Unusually, the directors decided to start operations by first building a tramroad as a way of raising extra revenue.

Within a year horse-drawn ‘drams’ were delivering coal from the Gelli-felen colliery near Bryn-Mawr down the Clydach valley and over the Usk to an iron forge at Glangrwyney. It wasn’t until 1797 that work actually started on the canal, commencing at Gilwern where it intersected with the tramroad and needed to cross a deep gorge carrying the River Clydach.

Company engineer Thomas Dadford solved the problem by engaging a contractor, Thomas Powell of Abergavenny, to build a rock and earth embankment 100 metre long and 25 metres high, burying the river in a deep tunnel.

A second tunnel through the embankment enabled the tramroad to pass under the canal.

This enormous undertaking became the Gilwern Aqueduct, an outstanding feature of the canal today.

Llangattock

When work started on the Brecknock & Abergavenny Canal at Gilwern in 1797, the canal company required the nineteen-mile length to the terminus at Brecon to be built first. The lower section to a junction with the existing Monmouthshire Canal at Pontymoile would come later.

Within a year the new canal had passed Llangattock, where the limestone high above the village at Daren Cilau was already being quarried for agriculture and industry.

After burning in kilns with coal, it was reduced to quicklime for use as fertiliser, mortar for building and an ingredient in the iron making process. The completed canal with its tramroad extensions to collieries and quarries greatly improved transport of coal and limestone, enabling large-scale production in new wharfside kilns.

The corrosive quicklime was then stored in barrels for despatch by cart or boat. The first limekiln at Llangattock appeared in 1815, expanding later to become the biggest of ten sites along the canal.

Although a major industry in the canal era, lime production quickly declined towards the end of the nineteenth century with the arrival of imported fertilisers. The scale of the surviving kilns gives some idea of their former importance.

Llangynidr

Construction of the canal under company engineer Thomas Dadford proceeded rapidly and by the end of 1797 eight and half miles had been completed from Gilwern to the village of Llangynidr.

This was excellent progress considering the difficult hilly terrain to be crossed on the way to Brecon. By routing the canal around the twisting contours of the hills Dadford managed to keep it on one level, an impressive engineering achievement giving some spectacular views across the Usk valley.

Llangynidr also provided a source of water for filling the canal, where it crossed the fast-flowing Afon Crawnon. Beyond this point the ground rose steeply and his only option was to install a series of five locks, lifting the canal a total of 55 feet.

Between the top two locks, he added a side pond ensuring an adequate reserve of water for their operation. Here was an opportunity for the village inn to cater for the labouring ‘navvies’ and later for the resting boatmen. It was a useful place as well to install a company depot, which is still there today alongside what is now Lock 65.