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Montgomeryshire Canal
Llanymynech to Newtown, Powys, Wales, UK
Montgomeryshire Canal
associated engineer
John Dadford
Thomas Dadford jnr
Josias Jessop
date  1794 -1797, 1815 - 1821
UK era  Georgian  |  category  Canal/Navigation works  |  reference  SJ252197
ICE reference number  HEW 1205
photo  © Crown copyright: Royal Commission on the Ancient and Historical Monuments of Wales | © Hawlfraint y Goron: Comisiwn Brenhinol Henebion Cymru
The Montgomeryshire Canal — ‘the Monty’, or the Montgomery Canal as it's now known — ran in its original configuration from a junction with the Ellesmere Canal at Llanymynech south to Newtown, in Powys, Wales. The canal is narrow, 41.5km long, and was constructed in two stages. Now only partly navigable, it is undergoing restoration.
Like other canals of the period, the Montgomeryshire Canal was built to transport goods and materials. In this case, the principal cargo was lime for the improvement of agricultural land in the rural Upper Severn Valley. Promoters of the canal included local landowners, hoping to maximise their investment from greater crop yields.
In 1792, a canal from Llanymynech, which is on the Wales-England border, southwards to Welshpool was suggested as an extension of the Ellesmere Canal (proposed 1791, Llanymynech Branch completed 1796). By 1793, it had been decided that the new canal should continue as far as Newtown.
In 1794, An act for making a navigable Canal from or near Porthywaen Lime Rocks in the parish of Llanyblodwell, in the county of Salop, to or near Newtown, in the county of Montgomery, and also certain collateral Cuts from the said Canal was passed. The canal company was authorised to raise £72,000 from shares, with a further £20,000 if required.
John Dadford (1769-1809) was appointed engineer on 18th July 1794, with his elder brother Thomas Dadford junior (c.1760-1801) as his assistant and advisor. However, Thomas probably didn't spend too much time on the Montgomeryshire Canal as he was concurrently engineering the Leominster, Monmouthshire and Brecknock & Abergavenny canals.
The canal follows a near level course along the Severn Valley for three quarters of its length. The largest earthwork on its route is a 1.1km embankment (SJ253134) carrying the water channel over Bele Brook Valley at Wern. Another substantial embankment, 350m long, 6m high and 30m wide, adjoins the Vyrnwy Canal Aqueduct (SJ254196). It has seven arches to let river floodwater through.
Difficulties during construction of the masonry aqueducts at Vyrnwy and Berriew (SJ188006) led to parts of the structures collapsing. John Dadford resigned in 1796, and was replaced by his father Thomas Dadford senior (1730-1809). Eminent canal engineer William Jessop (1745-1814) was called in to advise on remedial works.
By August 1797, 26km had been built, from Llanymynech — joining the Ellesmere Canal above Carreghofa Top Lock — to Garthmyl, with a 3.5km branch to Guilsfield. However, funding ran out and construction halted about 11km short of Newtown.
In 1815, an Act of Parliament was passed to raise £40,000 in new shares to complete the canal. The remaining 12km, from Garthmyl to Newtown, was constructed between 1815 and 1819 by a new organisation, the Montgomeryshire Canal (Western Branch) Company. The earlier stretch then became known as the Eastern Branch.
William Jessop's son, Josias Jessop (1781-1826), designed the Western Branch. It includes six locks 1.4m deep and 4.6m wide at the bottom. His three-arch aqueduct at Aberbechan (SO142935) suffered from similar defects as the aqueducts on the Eastern Branch.
The Western Branch had to be profitable, to merge with the Eastern Branch, so higher tonnage charges were imposed on cargoes. Nevertheless, the canals were a cheaper and more dependable way to transport heavy loads than the toll roads of the period.
In 1821, a further parliamentary Act sanctioned the altering the route of the Tanat feeder, to supply the water pound above Carreghofa Locks, and to make a navigable cut from the Guilsfield Branch. This consolidated the merger of the Eastern and Western branches, and fixed the official commencement of the Eastern Branch at 32m from the sill of the upper gate of the higher of the two Carreghofa Locks.
During the 1820s, the Vyrnwy Aqueduct underwent extensive repairs with cast iron strengthening bars. The Aberbechan Aqueduct was repaired, and partially rebuilt in the 1850s.
In 1840, there were as many as 92 lime kilns along the canal. They were supplied from limestone quarries at Llanymynech. The canal also powered a total of eight watermills — at Aberbechan, Berriew, Welshpool (three), Domen, Wern and Carreghofa.
The Shropshire Union Railways & Canal Company purchased the Eastern Branch in 1847 and the Western Branch in 1850. The Montgomeryshire Canal became part of the Shropshire Union network. It remained profitable until after World War I (1914-18) but trade dwindled thereafter.
In 1936, a breach near Frankton Junction on the Llangollen Branch of the Shropshire Union Canal separated the Montgomeryshire Canal from the national canal network. In 1944, Parliament passed an Act of Abandonment for the canal.
The route in Welshpool was threatened by road building in 1968 and, in October 1969, more than 200 volunteers from the Shropshire Union Canal Society cleared the channel through the town. Since then the society has been engaged in reinstating the canal, and its line has been partially restored.
The 1987 and 1988 British Waterways Acts conferred powers to restore and operate the canal, and renamed it the Montgomery Canal. In 2012, the Canal & River Trust took over from British Waterways.
By 2014, around half of the route had been fully renovated. From Llanymynech to Arddleen, for almost 10km, the canal is always in water. Five bridges have been decreased in height for road crossings. Between Arddleen and Efail Fach 17.7km of waterway are navigable. From Efail Fach to Freestone Lock, about 10km of the canal is in water, with five more dropped-height bridges. Towpaths between Newtown and Welshpool have been upgraded.
Future works to enable through travel will include re-opening 4.8km of dry canal north east of Llanymynech and towpath improvements between Welshpool and Llanymynech.
The canal’s abundant aquatic flora has led to its designation as a Site of Special Scientific Interest in England and a Special Area of Conservation in Wales. It is said to be one of the most beautiful waterways in Britain and its restoration will preserve many rare natural habitats.
Resident engineer (1815-21): John Williams
Research: ECPK
"The Archaeology of the Montgomeryshire Canal" by Stephen R. Hughes, Royal Commission on Ancient and Historical Monuments in Wales, 1989
reference sources   CEH W&WCEH Wales

Montgomeryshire Canal