The Monmouthshire Canal

This canal was authorised by an Act of Parliament, passed on 3 June 1792, which created the Company of Proprietors of the Monmouthshire Canal Navigation and empowered them to raise £120,000 by the issuing of shares, and a further £60,000 if required. The act stated that the canal would run from Pontnewynydd to the River Usk near Newport, and would include a branch from Crindau to Crumlin Bridge. The Company also had powers to construct railways from the canal to any coal mines, ironworks or limestone quarries which were within eight miles (13 km) of it.

Connstruction of the canal was supervised by Thomas Dadford, Jr., and further Acts of Parliament were obtained as the work progressed. An act of 4 July 1797 gave the Company powers to extend the navigation, which resulted in the Newport terminus being moved southwards to Potter Street, while a third act of 26 June 1802 authorised specific railways, and allowed the Company to raise additional finance.

As built, the main line, which was opened in February 1796 and was 12.5 miles (20.1km) long, ran from Newport to Pontnewynydd, via Pontymoile, rising by 447 feet (136.3m) through 42 locks. The 11 mile (17.7km) Crumlin Arm left the main line at Crindau, rising 358 feet (109m) through 32 locks to Crumlin (including the Cefn flight of Fourteen Locks), and was opened in 1799. In the late 1840s, a short extension joined the canal to Newport Docks, and hence to the River Usk. Because the canal was isolated from other similar undertakings, Dadford was free to set the size of the locks, and they were designed to take boats with a maximum width of 9 feet 2 inches (2.8m), a length of 63 feet (19 m) and a draught of three feet (0.9m).

On the main line, railway branches were constructed from near Pontypool to Blaen-Din Works and Trosnant Furnace. From Crumlin a railway was built to Beaufort Iron Works, which was 10 miles (16km) long and rose by 619 ft (188.8m), and there were additional branches to Sorwy Furnace, Nantyglo Works, and the Sirhowy Railway at Risca.

The Brecknock and Abergavenny Canal

This canal was first proposed in 1792 as a separate venture, to link Brecon to the River Usk near Caerleon. The Monmouthshire proprietors invited their potential competitors to alter the plans to create a junction with the Monmouthshire Canal at Pontymoile near Pontypool and share the navigation from there to Newport. An Act of Parliament was obtained on 28 March 1793, allowing the newly formed Canal Company to raise £100,000 in shares, with an additional £50,000 if required, and to construct railways to link the canal to mines, quarries and iron works.

Initially work concentrated on the railways, with John Dadford overseeing the construction of lines from the collieries at Gellifelen to Llangrwyney Forge, and on to the Abergavenny to Brecon turnpike road. The line was opened in 1794, and later served the canal at Gilwern. It was not until 1795 that Thomas Dadford was appointed as the engineer for the canal itself and construction began in earnest at Penpedairheol near Crickhowell. Work began in 1796 and by late 1797, the canal was open from Gilwern to Llangynidr in Brecknockshire and much of the rest was in hand. However costs, as usual, were higher than expected and, in 1799, the engineer, Dadford, stated that further money was needed to complete the section from Clydach to Brecon. Benjamin Outram was called in to inspect the work and to advise on substituting a railway between Gilwern and Pont-y-Moel. Outram recommended several improvements, in particular the partial rebuilding of the Ashford Tunnel. He was also somewhat critical of the existing railways.

The canal was completed and opened to Talybont-on-Usk in late 1799 and through to Brecon in December 1800. Thomas Dadford died in 1801, and was replaced as engineer by Thomas Cartwright. The Canal Company obtained another Act of Parliament on 3 May 1804, to authorise the raising of more capital, and the section to Govilon, near Abergavenny was completed in 1805, but the company failed to raise the finance authorised by the 1804 act, and so construction stopped. The company then concentrated on running the canal and railways so far opened, and were running twenty boats by 1806, carrying coal and limestone as their main cargoes.

By 1809 the Monmouthshire Canal was threatening litigation about the uncompleted connection from Gilwern. Help came from Richard Crawshay, the Merthyr Tydfil ironmaster and a major force on the Glamorganshire Canal, who provided a loan of £30,000. This sum enabled the canal company to appoint William Crosley to complete the work, which opened in February 1812.

From the Pontymoile junction, the Brecknock and Abergavenny runs through Llanfoist near Abergavenny and Talybont, ending at a basin in Brecon. The canal is 33 miles (53km) long and is level for the first 23 miles (37km) to Llangynidr, where there are five locks. Two miles (3.2km) below Brecon, the canal crosses the River Usk on an aqueduct at Brynich, and a final lock brings the total rise to 68 ft (20.7m). The River Usk provides the main water supply for the canal. A weir near the Brecon Promenade controls the water levels on the river, and half a mile (0.8km) of underground culvert brings water through the town to the Theatre Basin. Additional water is taken from a number of streams, where part of the flow is diverted into the canal and the rest flows under an aqueduct to reach the River Usk.