The Salisbury and Southampton Canal was intended to be a 13-mile long canal in Hampshire and Wiltshire, southern England. Its proposed route ran from Redbridge, now a western suburb of Southampton at the head of Southampton Water, to Salisbury, and connecting with the Andover Canal at a junction near Mottisfont. Another section, through Southampton, was to connect via a tunnel to the River Itchen. Part of the canal was built and was in use by 1803, but it closed amid financial failure in 1806.
History The idea of a canal from Salisbury to Redbridge was announced in 1768, after the canal engineer James Brindley had made a survey of a possible route. Two years later, Robert Whitworth was working on plans for a canal from Andover to Redbridge, and the Salisbury Committee wanted Brindley to survey an amended route that would join Whitworth's Canal at Kimbridge. Brindley was too busy and so sent one of his assistants, but the scheme foundered in 1772 when the Andover bill was not presented to Parliament.
The route was surveyed in 1793 and authorised by an act of Parliament, the (35 Geo. 3. c. 51). The proprietors appointed Joseph Hill as the surveyor, who estimated that the project would cost around £50,000. Although the canal had initially attracted strong support from merchants in Bristol, who saw it as part of a link between Bristol and Southampton, many of the shareholders did not respond to the calls for money, and so the company was always short of working capital. The job of constructing the tunnel in Southampton was given to Thomas Jenkins, but the work did not go well, and John Rennie was asked to inspect it. His report highlighted serious deficiencies with the work.
Hill resigned from the project shortly afterwards. A new act of Parliament, the Itchen Navigation Act 1800 (39 & 40 Geo. 3. c. cviii) was obtained, which authorised the raising of additional capital, but although the company found it difficult to obtain extra shareholders, they appointed George Jones as the resident engineer, and some progress was made. By January 1803, the canal was in use from the west end of the tunnel to Redbridge, where it joined the Andover Canal, and from Kimbridge, further north on the Andover Canal, to West Grimstead, to the east of Salisbury. The company struggled to find the money to continue construction, and sheriffs seized parts of the canal after Jones sued the company for failing to pay his salary and won the court action.
Tolls were collected until at least the end of 1804, and the canal was still being used for some months after that, but a lack of maintenance and some wilful damage resulted in the canal being closed in 1806. The company was defunct by 1808. Parts of the Salisbury arm soon became dry, and others became a small stream, but the section in Southampton became a stagnant ditch. In 1841 a woman drowned in the canal, after which the council took action and filled it in. Raising money and getting the legal powers, through the Southampton Marsh Act 1844, to fill canal in delayed work until 1846 and the final grassing over didn't take place until 1851.
Although some of this section was re-used by the Southampton and Dorchester Railway when it was constructed, plans to re-use the tunnel were abandoned when it was found to be unsuitable. A new, larger, railway tunnel was excavated on a different alignment and at a slightly higher level which resulted in the partial removal of the canal bore.Castlemans Corkscrew, Volume 1, The Nineteenth Century, B L Jackson, Oakwood Press 2007
Route
Southampton branch Very little remains of the Southampton Branch of the canal. In 1966, Edwin Welch produced a short book for the Southampton Records Office, the research for which included the production of annotated maps, based on 2.5-inch Ordnance Survey maps from the 1930s, to document the route. Development was rapidly obliterating what few remains there were.
The branch from the Test started close to God's House Tower, which at the time was on the riverbank; this area has changed a great deal, with reclamation of land for the ferry terminal.Ordnance Survey, 1:2500 map, 1897 and 2012 From there it headed due north. The street names of Canal Walk and Lower Canal Walk give some clues to the route, but the canal was filled in haphazardly in the middle of the 19th century, and was then built over. The street plans were altered significantly after the Second World War, when Queensway was built. When the Palmerston House housing project was being built on Queensway in 1961, excavations for the foundations located part of a wharf, but no drawings were made before it was buried beneath concrete.
The Test branch met the Itchen branch at the eastern end of the canal tunnel through the high ground to the west; the junction was just to the south of the railway's later Southampton Tunnel on the eastern edge of what is now Palmerston Park. The Itchen branch curved to the north-east to reach a lock in the vicinity of the wharf which was downstream of Northam Bridge. Construction of the Southampton and Dorchester Railway in 1846 and of a gasworks in 1848 destroyed much of the route, and excavations along this length in the 1960s failed to find any trace of it. Around 1998, a section was found during the construction of St Mary's Stadium and now lies beneath a railway footbridge. The tunnel beneath the Marlands area headed westwards from the junction. A depression in the ground on the Eastern side of Palmerstone Park now marks the site of this eastern tunnel portal which can be seen on old maps and plans and contemporary documentation. The 1846 street map of Southampton shows a row of houses at this location named "Canal View". The incomplete tunnel alignment followed a straight line to the western portal, its length recorded on contemporary company plans as either or .
The western portal was on the far side of the intervening high ground to the north of the current Kingsbridge Lane. The canal tunnel proved difficult and expensive to construct and canal company records indicate it was neither fully completed or used for traffic. Several sections sank or collapsed during construction due to geological conditions, poor materials or improper supervision of the works.
In the 1840s the Southampton and Dorchester Railway constructed a railway tunnel through this same high ground, cutting through the route of the canal tunnel at an acute angle towards the western portal. Early reports by the railway's engineer suggested it might be possible to use the canal tunnel in some way for the construction of the railway but by the time the bill for construction was placed before Parliament this idea had been rejected and a new alignment with a shorter tunnel was proposed. A contemporary cross-sectional drawing, made in June 1847, shows that close to the point at which the two tunnels met the base of the canal tunnel was only slightly lower than that of the railway tunnel, and that the level of the water it contained was at a similar level to the base of the new tunnel. The alignments and levels of the two tunnels meant that water was able to accumulate beneath the level of the newer, larger, structure and saturate the surrounding gravels and clays. Just before the railway tunnel's planned opening date, saturation of the ground around the area of the old canal tunnel was reported to be responsible for a collapse of a recently constructed 100-yard section at London Road on 23 April 1847.Hampshire Advertiser 2 May 1847 After repairs were completed and a formal inspection had taken place, a further 60-yard section began to sink and opening was delayed for two months whilst this was also dealt with. Captain Coddington, the Government Surveyor of Railways visited the site to report on the situation and recorded what had become of the canal tunnel:
"About 50 or 60 years ago a Tunnel was constructed for canal purposes which proved a failure and was abandoned, its direction was such as to cross very obliquely the line of the New Railway Tunnel and its level was about a foot below the level of the new tunnel. I enquired what precautions had been taken at the crossing, and was informed that the old Tunnel had been completely taken out...and in addition a length of 20 feet of the old tunnel on each side of the new one had been built up solid with rubble masonry...
"It appears that Mr Peto the contractor, for the accommodation of those parties whose property lies above the line of the old Tunnel...agreed to strengthen it by building a certain number of cross walls at short intervals...The mode adopted in doing it was to drive a small gallery laterally from the side of the new Tunnel to reach the old one at a point some distance beyond the 20 feet which had been solidly built up. Through this gallery the materials were introduced and 3, 4 or more cross walls about 10 feet apart were built within it...
"The old tunnel having been on a level and open at its extremities whatever percolation of water entered it either from the sides or above flowed out at both ends. The crossing of the new tunnel in no way affected this drainage...so the soil (a black Clay) continued firm enough to support the brickwork laid upon it. But by the filling up solid of a portion of it, leaving a hollow interval...the accumulation of water in seeking an egress has entered into, saturated, and sodden the clay on which the new Tunnel stands, and it is now incapable of supporting its weight."
The situation below ground caused problems when the foundations for Marland House were being dug in 1963, and the heading was reopened between the railway tunnel and the canal tunnel in 1965. This revealed that the brickwork was still in good condition at that point, but that the tunnel was largely filled with rubble as reported in 1847, and contained water below the level of the adjacent railway tunnel. The heading was sealed behind a partial relining of this section of the railway tunnel in 1983.
Further ground movements in 1975 led the city council to dig shafts at the former King Edward's School building on Havelock Road, and to drill boreholes into the remaining sections of the canal tunnel, to investigate the situation. The tunnel was entered via these shafts towards the western end and was pumped out. This allowed recording, measuring and photography before the tunnel was filled with flyash to prevent further ground movement. At this time, the former western tunnel portal lay beneath the then R J Mitchell museum to the north of Kingsbridge Lane. This area is today bounded by a multi-storey car park, a BBC site and Kingsbridge Lane pedestrian area. Early maps of this area show a water feature in the grounds of Kingsfield, and later Kingsbridge House and the school on the site. This appears on both the 1846 street map of Southampton and the 25 inch Ordnance Survey map dated 1897. A line drawn between this and an earthwork feature shown on the 1846 map in what later became Palmerston Park approximates to the documented length of the canal tunnel of between 560 or 580 yards. This earthwork feature lay just to the north of "Canal View" on this map, but no other details of the canal are shown around the tunnel area.
Ground movement within the railway tunnel has caused issues for the railway line since the 1960s when the invert was found to be rising, with work in 1965, 1983 and 2009. In 2009, freight trains were recorded as hitting the side of the tunnel as the track bed moved and works were done in conjunction with lowering the railway level by installing integral track in a new concrete base at the invert.