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Brynich Aqueduct
Llanfrynach, Brecon, Powys, Wales, UK
Brynich Aqueduct
associated engineer
Thomas Dadford jnr
date  April 1796 - 1800
UK era  Georgian  |  category  Aqueduct  |  reference  SO078273
ICE reference number  HEW 337
photo  © Crown copyright: Royal Commission on the Ancient and Historical Monuments of Wales | © Hawlfraint y Goron: Comisiwn Brenhinol Henebion Cymru
Brynich Aqueduct carries the Brecknock & Abergavenny Canal over the River Usk near Brecon. Now refurbished, the aqueduct is a substantial masonry structure with towpaths alongside the water trough. The canal, which is still in water, runs for 53km through the Brecon Beacons National Park. In Pontypool it joins the Monmouthshire Canal, and the two waterways are now known collectively as the Monmouthshire & Brecon Canal.
The "Company of Proprietors of Brecknock and Abergavenny Canal Navigation" was incorporated under a Parliamentary Act of 28th March 1793, and the cutting of the canal began in April 1796. Canal builder Thomas Dadford junior (1760-1801) acted as the company’s engineer from 1794, and was officially appointed on 1st January 1796. He retained the post until his death.
At the time he designed the aqueduct, Dadford was working on a number of other canal projects. Possibly he was overstretched because Benjamin Outram (1764-1805), another engineer with canal expertise, was asked to advise on the construction of the Brecknock & Abergavenny Canal.
In Observations on the Brecknock and Abergavenny Canal and Railways, dated 1st July 1799, Outram wrote of the aqueduct: "I have particularly examined the other parts of the Line proposed for the Canal between Tal-y-bont [Talybont-on-Usk] and Brecon, and advise a small deviation at the crossing of the Usk. I recommend the aqueduct to be erected upon a rock about two hundred yards below the New Bridge, instead of the situation above the bridge before proposed".
Following this recommendation, the aqueduct was constructed at Cefn Brynich about 3km east of Brecon, on the stretch of canal running south east from Brecon to Gilwern (completed by December 1800). The late 18th century New Bridge he mentioned still stands, also known as Lock Road Bridge (SO077272), and it carries the B4558 over the river on the west side of the aqueduct.
The reported timing of events shows little time was lost. On 8th July 1799, a contract of £2,200 was let for building Brynich Aqueduct, with completion stipulated by 29th September 1800.
The masonry structure is 64m long and 9.4m wide overall. It has four segmental elliptical arches each spanning 11m, separated by three 2.3m wide piers with straight pointed cutwaters up to voussoir level. The west elevation is higher as it incorporates a parapet wall. The canal channel narrows to a trough 3.65m wide over the aqueduct and has paths on both sides, with the west side towpath wider than the other. The water level of the canal is about 14.3m above the river bed. The east side of the aqueduct has metal railings of unknown date.
The Brecknock & Abergavenny Canal was extended from Gilwern to Govilon by 1804 and, in 1812, it was connected to the Monmouthshire Canal (completed 1799) at Pontymoile in Pontypool.
Some time in the late 19th or early 20th century, some of the arches were lined in black brick. In 1996-7, the whole aqueduct was restored.
Brynich Aqueduct, now owned by the Canal & River Trust, is a scheduled monument. The aqueduct and Lock Road Bridge are both Grade II* listed structures.
Contractors: Benjamin James and Walter Walters
Research: ECPK
reference sources   CEH W&WCEH WalesBDCE1

Brynich Aqueduct