The Neath and Tennant Canals are two independent but linked canals in South Wales that are usually regarded as a single canal. The Neath Canal was opened from Glynneath to Melincryddan, to the south of Neath, in 1795 and extended to Giant's Grave in 1799, in order to provide better shipping facilities. With several small later extensions it reached its final destination at Briton Ferry. No traffic figures are available, but it was successful, as dividends of 16 per cent were paid on the shares. The canal was long and included 19 locks.
The Tennant Canal was a development of the Glan-y-wern Canal, which was built across Crymlyn Bog to transport coal from a colliery on its northern edge to a creek on the River Neath called Red Jacket Pill. It closed after 20 years, but was enlarged and extended by George Tennant in 1818, to provide a navigable link from the River Neath to the River Tawe at Swansea docks. In order to increase trade, he built an extension to Aberdulais basin, where it linked to the Neath Canal. The extension was built without an act of Parliament and there was a long delay while Tennant attempted to resolve a dispute with a landowner over the routing of the canal. Once opened, much of the Neath traffic used the Tennant Canal, as Swansea provided better facilities for transferring cargo to ships.
Use of the canals for navigation ceased in the 1930s, but they were retained as water channels to supply water to local industries and to Swansea docks. The first attempts at restoration began in 1974 with the formation of the Neath and Tennant Canals Society. The section north of Resolven was restored in the late 1980s, and the canal from Neath to Abergarwed has been restored more recently. This project involved the replacement of Ynysbwllog aqueduct, which carries the canal over the river Neath, with a new plate girder structure, believed to be the longest single-span aqueduct in Britain. Some obstacles remain to its complete restoration. In 2003 a feasibility study was published, suggesting that the canal could become part of a small network, if it was linked through Swansea docks to a restored Swansea Canal.
Neath Canal Encouraged by the recent grant of an act of Parliament to authorise the building of the Glamorganshire Canal, it was resolved at a meeting at the Ship & Castle public house in Neath on 12 July 1790 to build a canal from Pontneddfechan to Neath, and another from Neath to Giant's Grave. Among those attending was Lord Vernon, who had already built a short canal near Giant's Grave to connect the River Neath to furnaces at Penrhiwtyn. Thomas Dadford was asked to survey a course, and he was assisted by his father and brother. He proposed a route which required 22 locks, part of which was a conventional canal, while other parts used the River Neath. Dadford costed the project at £25,716, but in early 1791 Lord Vernon's agent, Lewis Thomas, proposed two new cuts, and the idea of using the river was dropped soon afterwards.
The canal was authorised by an act of Parliament, the (31 Geo. 3. c. 85), passed on 6 June 1791, which created The Company and Proprietors of the Neath Canal Navigation, who had powers to raise £25,000 by the issue of shares, and an additional £10,000 if necessary. As well as building the canal, the canal company could build inclined planes, railways or rollers if required, and could optionally use the bed of the River Neath. The canal was to run from Glynneath (called Abernant at the time), which was not as far up the valley as Pontneddfechan, to Melincryddan Pill at Neath, where it would join the river. Thomas Dadford was employed as engineer, and construction started from Neath, northwards towards Glynneath. The canal had reached the River Neath at Ynysbwllog by 1792, when Dadford resigned to take up work on the Monmouthshire Canal. He was replaced by Thomas Sheasby, who failed to complete the canal by the November 1793 deadline given to him, and was arrested in 1794 for irregularities in the accounts of the Glamorganshire Canal. The canal company completed the building work by 1795, using direct labour, although the lock into the river was never built. Rebuilding of locks and other improvements continued to be made for several years afterwards.
There was no immediate pressure to extend the canal to Giant's Grave, as access to Neath for coastal vessels of up to had been improved in 1791 by the construction of the Neath Navigable Cut. However, a second Neath Canal Act, the (38 Geo. 3. c. xxx) was passed on 26 May 1798, to authorise an extension of about to Giant's Grave, where better facilities for transferring goods to seagoing vessels were available. Thomas Dadford again surveyed the route, but Edward Price from Gofilon acted as engineer. This part of the canal was financed by Lord Vernon, although he was also paid £600 for his Penrhiwtyn canal, which became part of the main line. The extension was completed on 29 July 1799, and terminated at a basin close to Giant's Grave Pill. Flood gates on the canal enabled water to be released into the pill to scour it of silt. The total cost of the project was about £40,000, which included 19 locks and a number of access tramways. Between 1815 and 1842, additional docks and wharfs were built at Giant's Grave, extending the canal slightly, and the canal was extended to Briton Ferry by the construction in 1832 of the Jersey Canal, which was about long, and was built without an Act of Parliament by the Earl of Jersey. Another short extension was made around 1842. The final length of the canal was .
From the northern terminus, a tramway connected the canal to iron works at Aberdare and Hirwaun. This was built in 1803, and included an incline just north of Glynneath, which was powered by a high-pressure Trevithick steam engine. The Tappenden brothers had bought into the iron industry in 1802, and built the tramway because of high tolls on the Glamorganshire Canal, but by 1814 they were bankrupt, and had no further connections with the canal.
Operation Mineral resources near the top end of the canal included ironstone, which was normally extracted by scouring. This caused problems for the canal, as silt was deposited in the feeders and the top pounds. The Fox family, who were based at Neath Abbey, but who were scouring ironstone further up the valley, agreed to construct a new feeder in 1807 to mitigate the problem. Protests made to the Tappendens, who were scouring at Pen-rhiw and Cwm Gwrelych, were less successful. As the pounds were silting up, the company took legal action in 1811. The court found in their favour, recognising that the canal would soon be useless unless something was done.
Trade steadily grew. Three small private branches were built to serve the industries of the valley. Near the top of the canal, a branch was constructed in 1800, which ran towards Maesmarchog, and was connected to collieries by nearly of tramroad. At Aberclwyd, a branch built in 1817 served the Cnel Bach limekiln on the river bank. Below Neath, a branch left the main line at Court Sart to connect to a tramroad serving the collieries at Eskyn. Although there are no figures for the tonnage carried, apart from a mention of 90,000 tons of coal in 1810, receipts increased from £2,117 in 1800 to £6,677 in 1830. Subscribers had paid a total of £107.50 for their shares, and dividends were paid from 1806, rising from £2 in 1806 to £18 in 1840. Based on the receipts, it has been estimated that some 200,000 tons of coal were carried when trade was at its peak, supplemented by iron, ironstone and fire clay.
Facilities at Giant's Grave improved, and included jetties to enable ships' ballast to be landed and dumped, rather than being thrown overboard. This latter approach had caused problems at Newport for the Monmouthshire and Brecon Canal, where ballast had been thrown into the river, and at Cardiff for the Glamorganshire Canal, where it had been thrown into the canal basin. Efforts were also made to improve the facilities at Neath. From 1818, a Harbour Board was established, and banks of copper slag, marked with buoys, were used to confine the channel. This enabled ships of over 300 tons to reach Neath quays on spring tides, although on neap tides Giant's Grave still had to be used. From 1824, when the connection to the Tennant Canal opened, much of the trade crossed the river and passed down the western bank to the port of Swansea.
Glan-y-wern Canal The Glan-y-wern Canal was built to connect Richard Jenkins' colliery at Glan-y-wern with the River Neath at Trowman's Hole, an inlet across the mud flats from the main channel of the river Neath, which was later known as Red Jacket Pill. Jenkins obtained a lease to build it from Lord Vernon on 14 August 1788, but died on the same day. Edward Elton took over management of the colliery, and the canal was constructed by 1790, although there was no actual connection to the river. At Red Jacket, cargos were transhipped from the small boats used on the canal to larger vessels in the pill, which was tidal. The canal remained in use for about 20 years. Elton became bankrupt and died in 1810 after which Lord Vernon, who had leased the land on which the canal was built to Elton, placed a distraint on the wharves at Red Jacket and on the barges and it became disused.
George Tennant incorporated the southern section into his Tennant Canal. The northern branch over the Crymlyn Bog was derelict by 1918. It branches northwards in Crymlyn Burrows and terminates at the Crymlyn Bog nature reserve, now a Site of Special Scientific Interest (SSSI). The SSSI covers an area of , and has been designated because of the presence of fen and wet woodland habitats. It is also a Ramsar site and a Special Area of Conservation. Rare flora and fauna include slender cottongrass, the fen raft spider, and groupings of rare and scarce invertebrates. Crymlyn Bog is now one of NRW's Lifequake Projects, and the Glan-y-wern Canal is scheduled to be cleared of overgrowth to improve drainage. Following this it will be linked to the Tennant Canal by a bridge, opening up access across the site. https://naturalresourceswales.gov.uk/about-us/news-blog-and-statements/news/lifequake-project-launch/?lang=en
The Tennant Canal George Tennant, born in 1765 and the son of a solicitor in Lancashire, moved to the area in 1816, after he had bought the Rhydings estate. The Glan-y-wern Canal was unused at the time, following Lord Vernon's distraint, but Tennant, who had no previous experience with canals, decided to lease it, enlarge it and extend it. He planned to make it suitable for barges of , which would gain access to the river Neath through a lock at Red Jacket. Where the canal turned northwards across Crymlyn Bog, he would extend it to the west, to terminate at a lock into the River Tawe, near Swansea harbour. He believed that Swansea docks would provide a better shipping point than Neath or Giant's Grave, and hoped that the canal would encourage the development of the corridor through which it ran. He attempted to gain support for the scheme from local landowners, but when none was forthcoming, he decided to fund the project himself. Lord Vernon's estate had been inherited by the Earl of Jersey in 1814, and so Tennant leased the Glan-y-wern Canal from him.