The first scheme was proposed by a group of Taunton men who invited the famous canal engineer, James Brindley, to investigate the possibility of a canal from Uphill, near Weston-super-Mare, to Burrow Bridge, then using the Tone navigation to Taunton, with another canal from Taunton to Exeter. Under Brindley's supervision, the survey was carried out in 1769 by Robert Whitwell, who also put forward an alternative scheme for a canal from Langport to Seaton. Nothing more was done until 1792, when a Bristol and Western Canal was proposed from the Avon, at Morgan's Pill, near Bristol, to Taunton, but this met with strong opposition from landowners who feared that the drainage of their lands might be affected. In 1796, however, after the Canal Mania of the years 1793-5 and when interest in canal building was declining, an Act was obtained to construct the Grand Western Canal from the river Tone at Taunton to Topsham on the Exe estuary, with branches to Tiverton and CuIlompton. Work on this canal did not begin until 1810 when a detached section from Tiverton to Holcombe Rogus, 11 miles all on one level, took four years to complete, but remained isolated until 1838 through lack of funds.

Meanwhile, the engineer of the Grand Western, John Rennie, had also undertaken the construction of the Kennet and Avon Canal from Bath to Reading. He realised the possibilities of a link between these two canals by means of a Taunton­Bristol section, and in 1811 an Act was passed to authorise this, with branches to Nailsea and Cheddar. Thus, it was hoped, a connection would be established by waterway between Exeter, Taunton, Bristol, Bath, Reading and London. Difficulties arose with the Conservators of the river Tone who felt that their navigation would no longer be needed. In 1822, after purchasing the financial interest of the Conservators, who, however, retained some control over the navigation, the Canal Company began the cutting of the Taunton­Bridgwater section of the proposed canal to Bristol. In 1827 the canal was opened from the Parrett, at Huntworth near Bridgwater, to the Tone, at Firepool near Taunton. Disputes which continued over the navigation rights on the Tone were finally settled in 1832, and in 1837 the canal was extended through Bridgwater to a new dock where ships could unload in safety instead of lying at riverside wharves, subjected to fast-running tides and the bore. This venture proved financially successful and in its best year, 1847, carried as much as 79,000 tons, mainly of coal from South Wales. When, in 1866, the Bristol and Exeter Railway bought the canal, a special Act was passed, mainly through the insistence of the Conservators of the river Tone, to ensure that there should always be 'a good and sufficient water communication between the towns of Taunton and Bridgwater'. The B. & E. made full use of the canal and the docks, but when taken over by the GWR the canal was neglected, though it still survives as part of a flood relief scheme, and is used by small pleasure boats and canoes.

The Grand Western, of which the Tiverton-Holcombe Rogus section had not proved successful, attracted the interest of the engineer, James Green, after the opening of the Taunton­Bridgwater canal. He put forward a modified plan for a narrow canal with 8 ton tubboats to complete the Taunton­Holcombe Rogus section. Instead of locks he proposed the construction of lifts and an inclined plane to secure a total rise of 262 feet. The design of the lifts was probably based on the experimental lift at Mells on the Dorset and Somerset Canal. It involved a carefully controlled counterbalance of two caissons, each in separate but adjoining masonry shafts, and linked by means of a chain and balance wheel. A tub-boat could be floated into the caisson at either the upper or lower levels of the canal. When the lift was worked by adding 2 ins of water, weighing about 1 ton, to the upper caisson, the greater weight gradually raised the lower caisson to the top of the lift and the boat could be floated out. Each lift did the work of several locks, using less water and saving time in the operation. However, much difficulty was experienced in making the lifts work and only part of the canal was opened in 1835, after nearly five years' work, as far as Bradford on Tone. Green was dismissed when the inclined plane at Wellisford failed to work by water power. In 1838 a steam engine was purchased to operate the plane and the canal was opened through to Tiverton. There was a short period of modest success until the branch railway reached Tiverton in 1848. After several years of competition and price cutting, the canal was leased in 1853 to the railway who bought it out in 1865 and closed down the Somerset section in 1867.

The Tone navigation had provided the inspiration for the diagonal line to link the two Channels. It was the Parrett navigation which gave rise to the schemes for the north­south link. In 1707 the Langport firm of Stuckey and Bagehot, who also traded from Bridgwater by sea and up the Severn, took over and developed most of the trade on the Parrett. In 1794 an Act was passed to authorise a canal from Langport, where the bridge made it necessary to unload the larger river boats, to Ilchester, but though some work was done in 1797 it was never completed. In 1836 an Act was obtained to improve the Parrett between Burrow Bridge and Langport, rebuild the bridge at Langport, and construct a canal to Westport. This was completed in 1840 and proved a profitable venture, but quickly met with competition from the Durston­Yeovil railway begun in 1847 and opened in 1853. Trade on the river and the canal gradually declined until 1875 when drainage problems became more important than the navigation.

The Parrett navigation had formed an important part of the plan put forward in 1768 for the inter-Channel canal to Seaton. During the Canal Mania in 1793 this plan was revived as a Chard Canal with connections to Bristol, and in 1809 the plan was again discussed as the English and Bristol Channels Canal at a meeting in Chard. James Rennie, who surveyed the proposed line, recommended a canal for small ships of 120 tons, from a harbour at Combwich on the Parrett to Seaton. The next move came in 1821 when Green, who had just completed the Bude Canal, suggested a tub-boat canal with inclined planes from the Tone to Beer. In 1824 Thomas Telford surveyed a line for a ship canal, 15 feet deep with 30 locks to take vessels of 200 tons, from Stolford on the coast of Somerset to Beer, via Creech St Michael, Ilminster and Chard. Harbours were to be constructed at Stolford and Beer, and a full-size branch to be extended to Taunton. An Act was passed in 1825, but financial difficulties put an end to the scheme. Several similar schemes were put forward for building canals between the two Channels, even as late as 1870, but none succeeded.

Chard had been included in many of the plans for the interChannel canal; and when these all failed, local people began to look for a link with the existing waterways. Of these the Taunton­Bridgwater Canal, opened in 1827, and the Westport Canal from Langport, first proposed in 1831, offered alternatives. Support came from the Taunton­Bridgwater Company and an Act was obtained in 1834 for a branch canal from Creech St Michael to Ilminster and Chard. In the 13½ miles of canal there were to be three tunnels, one of which was 1800 yards long, and four inclined planes. An additional Act was necessary to raise more money in 1840 to complete the complicated engineering work, and in 1842 the canal was opened. It was built for small tub-boats which alone could use the planes. For the first few years it was successful, but competition from the Bristol and Exeter railway (opened to Taunton in 1842) and from the Westport Canal (completed in 1840), soon began to threaten its existence. It continued in operation, serving many of the small towns and villages to the south of Chard with coal, fertilizers, salt, bricks, slates and timber, until bought by the Bristol and Exeter Railway in 1867 and closed in the following year.

To the east of the county another canal, the Dorset and Somerset, had been promoted during the Canal Mania in 1792 to link Poole and Bristol, by way of Wareham, Wincanton, Frome and the river Avon at Bath, with a branch to the Mendip collieries at Nettlebridge. In effect, this scheme was planned as an inter-Channel link and, like the others, was never completed. An Act was obtained in 1796 and work began on the branch from the collieries to Frome. Some experiments were made with lifts using the principle of counterbalanced open caissons which was adopted successfully later by Green, but the canal was never completed and the whole project was abandoned early in the nineteenth century. In the same part of the county, the Somersetshire Coal Canal, promoted in 1793 and authorized by an Act of 1794, formed part of the Bristol­London system. Its construction involved two interesting but unsuccessful experiments, one a lift and the other an inclined plane. The boat lift consisted of a watertight box, the caisson, into which a boat with its cargo and crew could be floated. The caisson then was raised or lowered by means of rack and pinion gears, within a masonry chamber full of water in which the caisson was completely immersed. At the top and bottom, closely fitted sliding doors in the lock and the caisson enabled the boat to enter or leave while the lock chamber remained full of water. The total height of the structure was over 80 ft with an operating height of about 60 ft. Though successful in many demonstrations, including one in the presence of the Prince of Wales in April 1799, difficulties arose through weaknesses in the caisson and in the masonry structure of the lock, and this project was also abandoned. An unsuccessful attempt was then made to construct an inclined plane, to be operated on the 'container' principle by which coal at the pit-head was put into boxes each containing one ton which could be loaded onto tramway trucks and transferred by crane to carriages on the incline. These were attached to an endless chain which passed round a drum to control the movement of the carriages descending by the force of gravity and pulling up carriages on the other side of the incline. At the bottom, the boxes were again lifted from the carriages into canal boats. This experiment was also a failure, and eventually a flight of 22 locks with a total rise of 154 ft was constructed. Most of the coal was brought on tramways from various collieries to the terminal basin at Paulton but for a time a branch canal was opened to Radstock though that, too, was converted to a tramway. The Somersetahire Coal Canal proved a most successful undertaking and carried more than 138,000 tons in its best year, 1838. Competition from railways brought about its gradual decline, though it continued to operate until 1898.