The Brecon and Abergavenny Canal compared to most proved quite difficult to build. As a result of this it also proved much more costly.
Many small aqueducts were needed because the route tended to go up small hills and down valleys. An aqueduct is a type of bridge which carries water deep enough for a canal barge, rather than a road or a railway track. The Brynich aqueduct is shown in this photograph.

At all times the engineers had to keep the waterway level. There were also several embankments which were mounds of earth built for the canal to pass over.

This is the Brynich aqueduct shown on an early map dated 1888. It was a four arched structure which took the Brecon and Abergavenny Canal over the river Usk just below Brecon.
There is another aqueduct at Gilwern with only one arch.

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