Category: Heritage

IWA’s Heritage Advisory Panel supported the North and East London Branch in objecting to a proposal from Canal and River Trust to dispose of the strip of land alongside Commercial Road Lock on the Regent’s Canal. IWA felt that disposal of this land threatened the canal’s heritage setting and amenity value.   

Taking Limehouse Basin as a meeting place for boats between the tidal Thames and the inland canals, this lock stands as a gateway to the canal system.  The two lock chambers fit neatly into the space between two historic bridges, twin arches of the Commercial Road Bridge and the fine single arch of the docks railway, now DLR. This canalscape is very important to the character of the designated Regent’s Canal Conservation Area and we felt that anything built on the site would inevitably damage these views.   

Additionally we believe that it is inappropriate to dispose of any land that forms part of the operational environment for a canal lock. The second chamber is an important heritage feature, and it deserves to be kept to show how the canal operated in its busy commercial days. It is also important to make sure that restoring the second chamber is possible in the future, even if not currently an option. 

Objections were also raised by the Friends of Regent’s Canal, the Commercial Boat Operators Association, the Lower Regents Coalition and the Greater London Industrial Archaeology Society. The Canal and River Trust responded to the objections saying that they have “carefully considered the various representations made”, and “accept that that the sale of this land on a freehold basis is not in the best interests of the Trust and we will not be progressing it.” 

IWA’s West Riding Branch heritage champions have saved this lock cottage near Halifax on the Calder and Hebble, at the last minute, from the auctioneer’s hammer.

IWA felt that in this case sale into private ownership was not the best future for the property as it is an integral part of the Salterhebble Basin and would compromise planned ambitions for regeneration of the local area. The basin consists of three distinctively different locks and a mooring pound for 10 boats. Outside of the basin, there is also an underused canal arm that could accommodate 10 more boats, and an unused dry dock in an area where these facilities are in high demand. It is also the step off point for the popular Hebble Trail. Access to the cottage is over a footbridge over the top lock and there is no road access for a cottage resident and it was felt that the health and safety restrictions that this would bring to Towpath users and boaters had also not been taken into account.

Salterhebble discussions are now in progress between IWA, the Canal and River Trust and the local council to develop the area and turn the heritage building in into a community centre for the local area, and the regeneration of the area will now be co-ordinated with the current and planned road improvements and planned national cycle routes. Initially the main focus will be on building a team from the local community, and education and practical skills experience will be top of the agenda. Everything will revolve around the canal environment and for the younger participants they will work towards bringing their learning to life using canal related activities such as C&RT Explorers. . For everyone else the focus is on boating, history and heritage – telling the story of the basin and looking to the future. If you would like to get involved, contact westriding@waterways.org.uk.

We have objected to plans to replace the historic Boxted bridge over the River Stour in North Essex, in support of a local campaign to protect the structure. Essex Highways has proposed demolishing the bridge and replacing it with a wider one.

Boxted bridge is in the heart of the Dedham Vale, a designated Area of Outstanding Natural Beauty. It is a steel girder bridge built in 1897 and an important part of the waterways heritage of the area. The river is popular for navigation by small craft such as canoes and paddleboards.

Replacing the bridge with a new and much wider bridge would be harmful to the setting of Boxted Mill. It would result in loss of a structure of intrinsic historic significance.

Alongside the community, we feel that the bridge should be repaired and retained, not replaced.

The answer is that they are places with aqueducts where one navigable waterway crosses over another. In fact, those six locations are the only places where this occurs on the main connected inland waterway network of Britain. The current structures all date from the 19th century and have listed status.

Three of these special aqueducts are on the BCN within about 4 miles of each other:

• Steward Aqueduct – Old Main Line crossing the New Main Line just before the top of Spon Lane Locks
• Telford Aqueduct – Engine Arm crossing over the New Main Line (near Smethwick).
• Tividale Aqueduct – Old Main Line crossing the Netherton Tunnel Branch

The next two are also geographically quite close to each other, and were both built by the Trent & Mersey Canal Company:

• Hazelhurst Aqueduct – Leek Arm crossing over the main line of the Caldon Canal
• Poole Aqueduct – Hall Green Branch of the Trent & Mersey Canal crossing over the main line of the Trent & Mersey Canal

And finally, the biggest and most well known…

• Barton Swing Aqueduct – Bridgewater Canal crossing the Manchester Ship Canal

Telford Aqueduct (1825)

The Engine Branch was built in 1789 to improve the water supply to the summit level of the Birmingham Canal (now known as the Old Main Line). This was originally from a pumping engine which gave the branch its name.

The cast iron aqueduct was built when Thomas Telford’s New Main Line was constructed through a cutting in this area. It was forged in 1825 by Horseley Ironworks in nearby Tipton. At this time, the Engine Branch was extended to carry water from the new Edgbaston Reservoir, part of Telford’s scheme.

The aqueduct is Grade II* Listed and also a Scheduled Ancient Monument. The aqueduct consists of a 52 ft cast iron trough supported by a stone arch. It carries the Engine Arm (which is on the Wolverhampton Level, 473 ft above sea level) over the New Main Line (otherwise known as the Birmingham Level, 453 ft above sea level).

Steward Aqueduct (1828)

Also known as Stewart or Stewards Aqueduct, this Grade II Listed aqueduct was built in 1828 by Thomas Telford. It was to carry the old line of James Brindley’s earlier Birmingham Canal over his New Main Line, at Spon Lane, Smethwick. Later, in 1852, it had a railway bridge built adjacent to it. The railway line ran parallel to, but much higher up than, the New Main Line. In about 1970, the M5 was built over the top, at a higher level still. The aqueduct is made of brick with sandstone dressings.

Poole Aqueduct (1828)

Most people think of this aqueduct as being the place where the Macclesfield Canal passes over the Trent & Mersey Canal. However, it is the Hall Green Branch of the Trent & Mersey Canal crossing the main line of that canal. The branch canal crosses the main line by the brick built aqueduct immediately downstream of Poole Lock, just the second lock down from the summit and the junction of the two canals.

The Trent & Mersey Canal Company’s Act of 1827 authorised them to build the first 1½ miles of the Macclesfield Canal’s line, and to charge tolls on cargo carried on it. The aqueduct was built in 1828 of red brick with a stone parapet, and is Grade II Listed. The Hall Green Branch, including Poole Aqueduct, was opened in 1831, at the same time as the Macclesfield Canal itself.

Hazelhurst Aqueduct (1841)

This aqueduct was part of the third arrangement of canals in the area around Hazelhurst and Hollinhurst on the Caldon Canal. When the canal was first built in 1778 the summit level was less than 2 miles long. However, it was extended when the Leek Arm was added (to supply water from Rudyard Reservoir) in 1801. This included a new staircase of 3 locks being built at Hazelhurst. The Leek Arm crossed the valley on a huge earth and stone embankment, joining the main line at a junction immediately above the staircase.

40 years later in 1841, the original line of the canal was reinstated. This was as a result of the staircase causing a bottleneck for traffic and being replaced by Hazelhurst New Locks. (3 separate locks actually at Hollinhurst, half a mile away). The embankment was pierced with a new aqueduct, taking the Leek Arm over the main line of the canal. The aqueduct is Grade II Listed and consists of a single arch in painted brickwork with stone dressings.

Tividale Aqueduct (1890s)

The Netherton Tunnel Branch (including the tunnel) was built in 1858 to improve communications between the Dudley and Birmingham canals. The original aqueduct on this site carried the original Birmingham Canal over the new branch canal. This was just a few hundred yards before the newer canal heads underground through Netherton Hill.

The aqueduct was rebuilt in the 1890s and the current structure is made of brick with sandstone keystones. It has two arches either side of a toll island, used for gauging boat traffic, and is Grade II Listed. An interesting feature, the water was run through pipes in the aqueduct from the higher canal through a turbine that drove a dynamo for the electric lighting in Netherton Tunnel. The pipes can still be seen on the south side of the aqueduct.

Barton Swing Aqueduct (1893)

The Barton Swig Aqueduct carries the Leigh Branch of the Bridgewater Canal over the Manchester Ship Canal. Often referred to as one of the wonders of the waterways, it was designed by Sir Edward Leader Williams. Completed in 1893, it was officially opened for commercial traffic on New Year’s Day 1894.

It consists of a 235ft long trough, weighing 1450 tons, that swings through 90 degrees on a central island. This allows unrestricted navigable headroom along the Manchester Ship Canal. The water in the higher canal is sealed off with gates at either end, and the aqueduct is swung using hydraulic power. The swing aqueduct is Grade II* Listed.

It dates from the building of the Manchester Ship Canal, and replaced an earlier aqueduct by James Brindley. The previous aqueduct, built in 1761, had been the first canal aqueduct in Britain. This original Barton Aqueduct carried the Bridgewater Canal over the Mersey & Irwell Navigation. So in itself, it was another, and indeed the first, crossing point of one navigable waterway over another.

We are delighted to hear that Shardlow has been awarded Inland Heritage Port status. IWA supported an application to the Maritime Heritage Trust earlier this year.   

Shardlow, close to where the Trent & Mersey Canal joins the River Trent, is thought to be England’s earliest most complete surviving example of an inland canal port. The village sprung up around James Brindley’s canal after it was completed in 1777, as part of his linking of the Trent and Mersey rivers by canal.  

Local IWA members supported the scheme, led by a local resident, for Shardlow to receive Heritage Inland Port status from the Maritime Heritage Trust. The Trust has already designated a number of Heritage Harbours around the coast. Recently, Chester became the first place on the inland waterways to become a Heritage Inland Port.   

We are campaigning for increased heritage protection on the waterways. The Shardlow Inland Port Steering Group will organise an annual festival and campaign for repairs to some of the village’s historic canalside buildings by encouraging investment through funding and grants. We hope that this, along with its conservation status and listed buildings designations, will help protect Shardlow’s unique heritage.

IWA volunteers in Scotland are campaigning for the repair of Dunardry Bridge on the Crinan Canal.

The only hand-operated rolling bridge which goes across a lock chamber, it is a unique example of waterways heritage. Whilst there are other moveable bridges across lock chambers and other rolling bridges, Dunardry Bridge is the only example of both.

Alison Smedley, then IWA Campaigns & Public Affairs Manager, said: “IWA believes that waterways heritage needs protecting. As part of our campaign to call for local authorities and navigation authorities to better protect waterways heritage, we are asking people to investigate their local canal or river in more detail than perhaps they ever have before and find items of interest. We want to make sure the quirky features of the waterways such as Dunardry Bridge are retained, ideally in working order, and are not forgotten in the future.”

Jonathan Mosse, IWA’s representative in Scotland added: “Whilst there are other moveable bridges across lock chambers and other rolling bridges, Dunardry Bridge is the only example of both. As such, we are working with Scottish Canals to explore options for how to repair it. We understand that Scottish Canals needs to concentrate its expenditure on improvements to navigation but IWA will fully support any heritage funding bid undertaken by Scottish Canals to reinstate the bridge.”

Find out more about hidden waterways heritage.

IWA’s Sue O’Hare walks us through the history and heritage of Britain’s bridges, how they have developed over time and highlights some fascinating but lesser-known bridges as well as better-known ones.

Bridge, Aqueduct, Tunnel?

The Oxford English Dictionary defines a bridge as “a structure carrying a road, path, railway, etc. across a stream, river, ravine, road, railway etc.” For the purposes of this article we will focus on bridges over waterways, rather than aqueducts carrying waterways themselves. Of course there are also aqueducts which carry one waterway over another. The main connected inland waterway network of Britain has six examples of these. But even having narrowed our scope, it is still a bit blurry. When does a bridge become a tunnel?

The Earliest River Crossings

Places where rivers could be crossed are historically important as they often developed into settlements. Many town or village names reflect these origins (for instance, both Cambridge and Oxford).

The earliest river crossings were probably fords, shallow places where people, animals and vehicles could cross. The Romans sometimes paved the fords to make crossing easier. For example, this was done at Littleborough between Torksey and Gainsborough, probably the lowest crossing of the Trent.

Ferries were the next stage of evolution and also have a long history. The Queensferry Passage route across the Firth of Forth dates from the 11th century. A river crossing service across the Mersey is said to have operated since the 1150s.

Medieval River Bridges

Bridges were much more expensive than fords or ferries. That said, they were safer, had higher capacity and could be used in most conditions. The Romans built many bridges in the UK, but they were constructed of timber and none have survived. Again on the Trent, there was a Roman bridge just below the site of the current Cromwell Lock at the head of the tidal section.

Our oldest surviving waterway bridges are medieval in origin. Perhaps the oldest is High Bridge in Lincoln, which was built about 1160 and carries the High Street across the Witham Navigation. It is likely that it replaced a timber bridge carrying the Roman road Ermine Street, possibly originally built as early as the 1st century AD. The bridge now supports a row of Tudor timber-framed shops. Bridges like this were common in the Middle Ages, the best known being the old London Bridge.

Most medieval bridges were removed a long time ago because they obstructed the river flow and shipping. Only High Bridge and Pulteney Bridge in Bath survive in Britain as waterway bridges with buildings on them. The narrow, crooked arch of High Bridge is often called the ‘Glory Hole’. It was also called the ‘Murder Hole’ in the medieval period, when it was said that murder victims would be dropped in the river there and eventually float out to sea. The bridge limits the size of boats that can navigate between the Fossdyke at Brayford Pool and Boston and the sea.

Ferrybridge in Yorkshire demonstrates the evolution from ferry to bridge in its name. It stands where the Great North Road (the A1) crosses the River Aire. The first bridge was built in 1198 but collapsed in 1228, resulting in the drowning of crusaders passing over at the time. In 1804, a larger bridge replaced the rebuilt bridge. Architect John Carr of York designed it to accommodate the increasing traffic on both the road and the Aire and Calder Navigation. In turn this was superseded by the modern A1 bridge in 1967.

The River Avon has a good number of bridges of medieval origins, some of which can be quite challenging to both boaters and vehicle drivers. A good example is Bidford Bridge in Bidford-on-Avon, remembered by Shakespeare as “drunken Bidford”, where the single navigation arch is unusually close to one bank of the river. Similarly the navigation arch of the medieval bridge over the River Medway at East Farleigh in Kent is not in line with the adjacent lock. The bridge dates from the 14th century. It is set amid orchards and oasthouses and has been described as ‘the finest bridge in the south of England’. Cromwell’s parliamentary troops marched over it in 1648 on their way to fight the Royalists in Maidstone.

On the Thames the oldest bridge is at Radcot, near the junction with the Thames and Severn Canal at Lechlade. The three-arch bridge now crosses a backwater. It is believed to date from the early 13th century, slightly pre-dating New Bridge further downstream near the confluence of the Thames and the Windrush. The Nene also has some old bridges, the most notable being at Irthlingborough with 19 arches and built during the 14th century.

On the River Dee in Chester a bridge was recorded in the Domesday Book, and the Old Dee Bridge was rebuilt in 1387 from red sandstone with seven arches, all with different dimensions. Cambridge offers the unique experience for powered craft of navigating the Backs. This is the stretch of the River Cam flowing behind several of the colleges, giving the classic view of King’s College Chapel. There are many old bridges to negotiate as well as punt traffic, so it is only permitted in winter.

Role of the Church

In medieval England it was often religious communities which built and maintained bridges. This is because they possessed the capacity to raise finance and the necessary architects and builders. Abingdon Bridge on the Thames was built in 1446 by the Fraternity of the Holy Cross. Radcot Bridge used to be surmounted by a cross, in accordance with the sacred character of bridges. Indeed indulgences were granted by the Church to those who contributed to bridge building and repairing.

It was common across Europe to build chapels on or near bridges. They catered for the spiritual needs of travellers and pilgrims. Many chapels were established as chantries, where a priest would say masses for passers-by and for the repose of the souls of the bridge’s benefactors. They were swept away by the Reformation through the Abolition of Chantries Acts of 1547 and 1549. Only four survive – at Bradford-on-Avon; St Ives on the River Great Ouse; Wakefield on the River Calder; and Rotherham on the River Don.

There was relatively little further major bridge building activity for the next two hundred years. The coming of the canals changed all that.

Canal Bridges

The cutting of canals across the landscape divided estates and farms as well as roads and tracks. Canal builders had to reconnect them by providing large numbers of bridges. We are fortunate that many of the bridges have survived in their original form. Sometimes the canal engineer was responsible for the design of the bridges and there are examples by Brindley, Rennie and Telford. However they were often subcontracted to local builders. Constructed from local materials, they blend into the surroundings in a way which has been enhanced by weathering and mellowing over time.

Canal bridges are many and varied (Canal and River Trust alone is responsible for over 3,000). Most were built during the 80 years from 1760 to 1840. There are two basic types: fixed and moveable.

Fixed Canal Bridges

The single-arched humpback bridge is by far the most common type, carrying a minor road or providing agricultural access. Local materials include stone (in the north of England and the Cotswolds); red brick (in the Midlands and the south); Birmingham ‘blue brick’; and later cast iron. More recent additions or replacements have used modern materials such as reinforced concrete or steel.

Even the simple humpback bridge can be visually striking. Brindley’s unusually wide arch at Great Haywood Junction in Staffordshire must be one of the most frequently photographed.

The high bridges spanning the Shropshire Union Canal’s deep cuttings are up to four times as high as normal bridges. Early bridges were all aligned so that they crossed the canal at right angles. However, in 1797 William Jessop designed the first true skew bridge, March Barn Bridge on the Rochdale Canal. Jessop used the method developed by William Chapman for the Kildare Canal in Ireland, with winding courses of stone to solve the problem of the angle.

Where canals crossed estates whose owners needed to be kept happy, much grander designs of bridges were used. Examples include Cassiobury Park at Watford on the Grand Union Canal and Chillington near Brewood on the Shropshire Union Canal. There is also the Gothic-style Drayton Turret footbridge over a swivel bridge on the Birmingham & Fazeley Canal near Sir Robert Peel’s Drayton Manor.

The unusually-shaped Cherry Eye Bridge on the Caldon Canal is also thought to be in deference to the local landowner (its name comes from a condition of the local ironstone miners’ eyes).

Many interesting and distinctive features of canal bridges were developed because they were needed to work the canals.

• Wear: Generally the towpath continues through the arch of the bridge, but this soon led to wear from constant abrasion by boat lines. Cast-iron protection plates were later installed on the bridge sides, which in turn acquired deep grooves.
• Dealing with towropes: Sometimes the narrowness of the arch did not allow for a towpath, and a narrow arch or small tunnel was provided for the horse. One way of dealing with the towrope in this situation was to use a split bridge with twin arms leaving a central gap for the rope. Examples of this can be seen on the Stratford-upon-Avon Canal in particular. Where the towpath changes from one side of the canal to another, a special form of bridge was designed to stop the towrope being tangled. These are known as roving, turnover or ‘snake’ bridges and are especially common on the Macclesfield Canal. They have such beautifully flowing lines that they are one of the most attractive waterway features.
• Crossing locks: Many locks have small bridges at the tail to avoid the need to use the walkways on the gates. These may be wooden, brick or concrete.
• Night navigation: On some canals such as the Leeds and Liverpool the bridge arches were whitewashed and the centre of the navigable bridge hole marked with a vertical stripe. These features can still be seen.

Once the use of cast iron for bridges was established at Ironbridge on the River Severn in 1781, it became an increasingly common material for canal bridges. Its strength and lightness enabled longer, flatter arches. The Horseley Ironworks of Toll End in Birmingham developed a signature bridge design. This was used widely around the BCN over the period 1820-30, and at Braunston Junction between the Oxford and Grand Union Canals. Another notable example is the Britannia Foundry Derby bridge at Hawkesbury Junction between the Coventry and Oxford Canals.

Later canals have grand bridges across deep cuttings. Perhaps most famous is Telford’s Galton Bridge, 75 feet above the Birmingham Main Line. The design is similar to his Holt Fleet Bridge and Mythe Bridge over the Severn. These were later followed by William Tierney Clark’s designs for Marlow Suspension Bridge; the original Hammersmith Suspension Bridge over the Thames; and perhaps most impressively by Brunel’s Clifton Suspension Bridge over the Avon Gorge below Bristol.

The coming of the railways brought new forms of bridge to the canal, starting at Patricroft Bridge on the Bridgewater Canal. This was designed by George Stephenson to carry the first passenger railway (the Liverpool and Manchester Railway) across the first major industrial canal. Some spectacular bridges and viaducts followed, including two particularly striking Pennine examples, both skewed: the castellated Gauxholme Viaduct over the Rochdale Canal near Todmorden; and the Saddleworth Viaduct carrying the railway over the Huddersfield Narrow Canal near Uppermill, which itself is crossing the River Tame on the Saddleworth Aqueduct. Also memorable are Brunel’s red-brick railway bridges over the Thames at Moulsford, Basildon and Maidenhead.

Completing the picture are the bridges that carry pipes and other industrial features over waterways. They range from simple pipes, to the Tata chemicals works that straddle the Trent and Mersey Canal at Wincham near Northwich.

Moveable Canal Bridges

Moveable bridges are cheaper to build but more expensive to maintain, and can cause delays for both boats and traffic crossing the bridge. They tend to be mainly used for farm or pedestrian access and on navigations used by large ships. In England and Wales moveable bridges are generally operated by the boat user except on the large navigations, whereas in Scotland this has been much less common.

There are three main types:

Bascule bridges or drawbridges
These are often referred to as lift bridges and lift up from one side of the waterway. They are counterweighted and usually operated manually or with a windlass. Most are found on narrow canals such as the Llangollen Canal and South Oxford Canal. However the broad Basingstoke Canal has a powered lift bridge at North Warnborough. Broad lift bridges are also used on the Lowland Canals in Scotland.

Swing, swivel or turnbridges
These are simpler, turning round a single point. Usually they are pivoted on one bank, though there was a railway swing bridge at Endon on the Caldon Canal which pivoted in the middle of the waterway. Swing bridges are especially common on the Leeds and Liverpool Canal, where many have been converted to electrical operation. They are also common on waterways used by tall vessels, such as the Gloucester and Sharpness Canal, the Manchester Ship Canal, the disused Sankey Canal, the Yorkshire waterways and the Weaver Navigation.

When railways were first built they generally crossed canals on the level in order to avoid the need for earthworks and gradients. For this reason they used swing bridges, as can be seen near each end of the Caledonian Canal at Banavie and Clachnaharry. The early exception was George Stephenson’s Liverpool and Manchester Railway, which crossed the Sankey Canal on the 1830 Sankey Viaduct near Earlestown – the earliest major railway viaduct in the world.

Vertical lift bridges
Here the bridge deck remains horizontal while being lifted vertically. The Huddersfield Broad Canal has the Turnbridge, also known as the Locomotive Lift Bridge, which was originally operated by windlass but is now electrified. In 1934 West Riding County Council built an electric lift bridge across the Barnsley Canal near Royston, but the canal was abandoned in 1953. Also opened in 1934, the Tees Newport Bridge was the first large vertical-lift bridge in Britain. It links Middlesbrough with Stockton-on-Tees. It no longer lifts, but still acts as a road bridge.

Two modern examples have been built across the Manchester Ship Canal. The Centenary Bridge is a road bridge linking Eccles with Trafford Park. It was opened in 1994 as part of the Manchester Ship Canal’s centenary celebrations. The Salford Quays Millennium Bridge, also known as the Lowry Bridge, is a footbridge opened in 2000 beside the Lowry Centre. It links Salford Quays with Trafford Wharf and the Imperial War Museum North. It has a lift of 60 feet and a custom lighting system, and is featured in the opening of the BBC North West Tonight TV news show.

Other rarer types of moveable bridge include:

Transporter bridges
These carry a gondola across a waterway, suspended from a tall span on wires or a metal frame. The concept was invented in 1873 by Charles Smith, the manager of an engine works in Hartlepool. It was useful in locations where it was impractical to build the long approach ramps needed to reach a high span, and in places where ferries are not easily able to cross. However transporter bridges can carry only a limited load and the idea has been little used since traffic grew.

The Widnes and Runcorn Transporter Bridge was Britain’s first transporter bridge and the largest of its type ever built in the world. Completed in 1905, it crossed the River Mersey and the Manchester Ship Canal. The two towers were 180 feet high and the transporter car was designed to carry 4 two-horse farm wagons and 300 passengers. It took 2½ minutes to cross in reasonable conditions. It continued in use until 1961, when it was replaced by the conventional Silver Jubilee Bridge and demolished.

There are only three remaining transporter bridges in the UK: the Tees Transporter Bridge in Middlesbrough, the Newport Transporter Bridge across the River Usk in Wales (currently closed for restoration) and the Warrington Transporter Bridge (now disused). The Royal Victoria Dock Bridge in East London is a modern footbridge designed to allow use as a transporter bridge but currently only used as a high-level footbridge.

Roller bridges
This is another way to tackle the problem of crossing navigable water in flat surroundings without needing earthworks and excessive gradients to reach a high bridge. An amateur industrial archaeologist recently rediscovered a railway rolling bridge across the abandoned Ulverston Canal in Cumbria. The bridge was built in 1883 by the engineer Frank Stileman. It carried the railway track diagonally and crossed the canal at towpath level. To enable boats to pass, the central part of the bridge was rolled back on wheels into a small dock built into one bank. The bridge was listed in 2012 and is believed to be the only surviving example of its kind in Europe. There is also a modern rolling footbridge across the Forth and Clyde Canal at Speirs Wharf in Glasgow.

Modern Bridges

In the 20th century the focus on building and improving roads led to the upgrading of existing bridges and the building of new ones. Highway authorities started replacing or widening original canal bridges before the Second World War, often with rather utilitarian structures. The motorway network then made a substantial impact. The first section of the M1, opened in 1959, included a crossing of the Northampton Arm of the Grand Union Canal almost above Lock 12. The concrete pipe-like structure has been considerably enlivened by murals depicting the history of Northampton and the canal’s natural history, painted by local school children working with the IWA Northampton Branch.

On the BCN the elevated section of the M5 runs to the north west of the city centre across Titford Pools and is built directly above the Old Main Line in Oldbury. There is an unusual juxtaposition of transport routes where Telford’s Steward Aqueduct carries the Old Main Line across his New Main Line, which in turn is crossed by the Birmingham and Wolverhampton section of the West Coast Main Line railway and above that the M5.

The M5/M6 junction at Gravelly Hill north east of Birmingham city centre, known as Spaghetti Junction, is more or less directly above Salford Junction. Again this is a fascinating story of Britain’s transport infrastructure, on multiple levels. The Grand Union Canal, Tame Valley Canal and Birmingham & Fazeley Canal meet at Salford Junction, as do the motorways, the A38 and A5127 roads, the Cross-City and Walsall railway lines, the Rivers Tame and Rea and Hockley Brook, as well as electricity lines and gas pipelines. The design requirements included the placing of the pillars to allow a horse-drawn narrowboat to pass without its towrope being fouled.

Perhaps the most intriguing media appearance of Spaghetti Junction is in the 1973 film Take Me High, when Cliff Richard sped below it on a hovercraft. This little-known film foresaw the regeneration of Birmingham around its canals, as well as the gourmet burger!

One of the most recent motorway bridges is the M5 culvert on the Droitwich Junction Canal. This originally carried the Body Brook and now has another role as part of the restored canal. It has an exceptionally low air draft of a nominal 6 feet, which can be further reduced by the flow into the canal from the Brook.

The Millennium in 2000 brought a wide range of interesting new bridges, including Millennium Bridges in Exeter, Glasgow, London, Teesquay (Stockton-on-Tees) and York. A particularly unusual example is the Gateshead Millennium Bridge. This is a tilt bridge, with a deck for pedestrians and cyclists and a supporting arch. To allow boats to pass, the arches rotate together around a pivot on each side of the river – hence its nickname of the ‘winking bridge’. Only two others of this type are known, both in Belgium.

Innovative bridges are also popular as part of regeneration programmes, as at Salford Quays.

Other examples include

• Merchant’s Bridge across the Bridgewater Canal at Castlefield in Manchester
• Islington Place Bridge over the Birmingham & Fazeley Canal at Farmer’s Bridge in Birmingham
• Diglis Bridge across the Severn in Worcester
• The Infinity Bridge in Stockton-on-Tees, named because the bridge and its reflection make up an infinity symbol.

Paddington Basin on the Paddington Arm of the Grand Union Canal in London has two unusual bridges. It used to have a third, the Helix Bridge, but this was removed in 2013. It was a glass and steel pedestrian bridge with a helical frame which rotated as the bridge retracted, to look as if it was corkscrewing across the canal. The two remaining bridges act as both pedestrian crossings and moving pieces of public art. The Fan Bridge splays like a fan as it rises, while the Rolling Bridge curls itself up into a ball.

Britain’s canals and rivers are a unique, living heritage – they tell the story of our industrial past. Yet that heritage is at risk – from urban development, lack of protection, loss of skills and knowledge and climate change.

IWA has launched a campaign to raise awareness of the heritage that makes our waterways so unique, from the variety of smaller details and marks to the impressive feats of industrial engineering. And more than this – it’s the culture, crafts and skills – that make our inland waterways a living heritage.

Our Waterways: A living heritage

Hear from Giles, Matthew, Abbey, Charlotte and Simon about their passion for Britain’s unique industrial heritage. This new video highlights the importance of protecting the heritage features that can be found along the waterways as well as the skills and traditions that live on today.

Save waterways heritage

There are four easy ways that you can help to Save Waterways Heritage.

1. You can help save waterways heritage by discovering hidden gems near you. Sign up to receive our ‘waterways heritage spotter guide’ – plus the latest heritage updates, and inspiration
2. Explore your local waterway for examples of hidden heritage that you might not have spotted before and capture them
3. Share your hidden heritage gems with us and post them to social media with #SaveWaterwaysHeritage
4. Make a donation to our Save Waterways Heritage appeal

Perhaps you already have a good story to share about something local to you – or you might find something unusual that we can help identify. We will be sharing examples of these intriguing marks and details that tell their own special stories through our social media channels.

Find out more about waterways hidden heritage.

IWA Navigation Committee’s Sue O’Hare guides us through the oldest, longest, widest and brightest tunnels on the canals.  Read on to find out about the tunnel that contained a canal and railway side by side and the tunnel that is now the site of Europe’s largest bat colony.

Tunnels are a fascinating part of canal cruising, a separate world seen only by boaters and wildlife. But just how much do we know about them?

When is a tunnel not a tunnel?

A tunnel is defined by the Oxford English Dictionary as “an artificial underground passage, especially one built through a hill or under a building, road, or river”. So how does the 25-yard Dunsley Tunnel on the Staffordshire & Worcestershire Canal qualify as a tunnel, when modern motorway bridges such as the culvert under the M5 on the Droitwich Canal do not? Is it perhaps because the Dunsley Tunnel goes through the ground as opposed to a man-made structure? Then why is Deansgate Tunnel carrying the Rochdale Canal underneath Deansgate in Manchester a tunnel?

Following in the footsteps of the Persians

In the 1st millennium BC the Persian people developed a system of qanāts, gently sloping tunnels to transport water from underground sources for irrigation and domestic use. The idea spread throughout the Middle East and North Africa and qanāts are still in use today.

The first canal tunnel

The first navigable canal tunnel was the Malpas Tunnel, built in 1679 to enable the Canal du Midi to pass under the hill d’Ensérune in the department of Hérault in the south of France. The chief engineer Pierre-Paul Riquet was able to overcome the challenge of tunnelling through brittle sandstone by lining the tunnel with stone vaulting, creating a wide and high 180-yard tunnel. The hill was already the site of a tunnel dug in the Middle Ages to drain the Étang de Montady, and this is said to have provided inspiration for Riquet.

Mines and tunnels

It was almost 100 years later that the first navigable tunnels were built in the UK, first in connection with mines and then on canals built for other purposes. The link with mining was obvious: miners were the only people with digging skills, and mines needed both transport and drainage.
Wet Earth Colliery in Clifton to the north west of Manchester was the location for the earliest water-carrying tunnels, engineered by James Brindley to drain the mine. Brindley designed a complex scheme involving a weir on the River Irwell to create a head of water, which was carried under the river into the mine through an inverted siphon sinking to a depth of 53 feet. It then turned a waterwheel which drove an underground beam pump. The system was completed in 1756 and was so successful that the basic components continued in use for 170 years. The remains can still be seen in what is now Clifton Country Park.

When Francis Egerton became the 3rd Duke of Bridgewater and hired John Gilbert as factor for his estates, they realised the need to improve the productivity of the mines to meet the increasing demand for coal in Manchester. Inspired by Brindley’s work at Clifton, they hired him as surveyor. The first part of their solution was to build the Bridgewater Canal from Worsley to Salford to provide better transport for coal. The other part was to extend the canal underground at Worsley Delph, an old sandstone quarry. This work was started around 1760 and created a multi-functional ‘Navigable Level’ which could drain the mines, provide an integrated transport system, and provide a water supply for the canal. An underground canal network was developed as new coal seams were discovered. Special boats nicknamed ‘starvationers’ were used, 4½ feet wide with protruding ribs inside. By the time coal transport along the Navigable Levels ended in 1887, there were about 47 miles of underground canal on four different levels, connected by a water powered inclined plane and lifts. The system continued to be used for drainage with regular inspections by boat until it was finally closed in 1968.

In a similar way limestone was transported out of the quarries at Dudley along branches dug from the Dudley Tunnel on the Dudley No. 1 Canal, and coal at Harecastle on the Trent and Mersey. Ironically it was mining, one of the original reasons and enablers for tunnels, which led to the downfall of many tunnels through subsidence. Unlike its neighbour the Lapal Tunnel, the Dudley Tunnel survived subsidence, only to be closed through disuse. Through a huge effort by the Dudley Canal Trust it was reopened and is now the second-longest surviving tunnel. It is a particularly intriguing place to visit, with its basins open to the air, its limestone caverns and its network of side tunnels. While it is open to navigation, it is very low and no engines are permitted, so most visitors take an electric trip boat operated by the Trust.

Tunnel Mania

As canals spread so too did tunnels. The Trent and Mersey Canal is well known as a pioneer, boasting perhaps the first of all navigable tunnels to be opened on the main system at Armitage in 1770 – though this no longer exists as a tunnel, having been opened out in the 1970s after subsidence caused by coal mining. The southern section of the Staffordshire and Worcestershire Canal with its short tunnels opened in the same year.

^{Photo: Armitage Tunnel during removal of the tunnel roof in 1971. Photo by Harry Arnold, Waterways Images.}

The three tunnels on the northern Trent and Mersey at Preston Brook, Saltersford and Barnton were among the earliest tunnels of substantial length, and are well known for their lack of straightness. Brindley’s first tunnel at Harecastle on the same canal is often thought of as an early leader for length at 2,880 yards, although his Norwood Tunnel on the Chesterfield Canal predated Harecastle as well as being the longest canal tunnel in Britain when it was opened in May 1775. Subsidence from nearby mining caused sections to sink and it eventually collapsed completely after heavy rain in 1907. The western end was filled in to enable the M1 to be built, although the eastern end is still in remarkably good condition and CRT invited members of the public to explore it during the 10-yearly inspection in 2016. The Chesterfield Canal Trust continues to develop options for replacing the tunnel in order to re-open the whole of the 46 miles of the canal, facilitated by the recent confirmation of a new route for the West Midlands to Leeds HS2 line around Norwood, running over the line of the Chesterfield Canal restoration on an embankment. The Chesterfield Canal Trust supported by IWA and CRT has proposed that the embankment be replaced by a viaduct, so that the canal could be restored on an east-west alignment giving fantastic views out to the west. The tunnel could be opened out again as a tribute to Brindley’s original work, and it might be possible to use the old canal line and reservoirs to drain the HS2 track and keep the restored canal locks topped up – and James Brindley would have the last laugh!

^{Photo: Norwood tunnel portal on the Chesterfield Canal line.}

On the Cromford Canal in Derbyshire, the Butterley Tunnel of 1794 was at the time the third longest. It included an underground wharf where narrowboats were loaded with coal. Vertical shafts above the wharf enabled goods to be transported between the canal and the Butterley Company’s works on the hill above the tunnel, using a system of ‘tram boxes’ which were containers used on the Little Eaton tramway as well as carts on roads, narrowboats on the Chesterfield Canal and barges on the Derby Canal. Mining-related subsidence again claimed this tunnel.

In Shropshire a network of ‘tub boat’ canals was built to transport coal, limestone and ironstone from mines and quarries to blast furnaces producing cast iron and wrought iron. The tub boats were built of wrought iron and were rectangular, about 20 feet long and 6 feet wide, and were pulled in trains of up to 20. The 970-yard Berwick Tunnel was opened in 1797 and was the first of any length to be built with a towpath. The tunnel was not straight and it was not possible to see the far end, so a byelaw was introduced giving right of way to whichever boat reached the centre mark first while the other boat had to reverse out of the tunnel before trying again. The tunnel remains, although both ends have been bricked up.

As tunnels became more widespread, so they began to develop from the early narrow, mine-like structures. First towpaths spread, then came wide tunnels such as Sapperton Tunnel on the Thames and Severn Canal, Wast Hill on the Worcester & Birmingham Canal, Foulridge on the Leeds & Liverpool Canal, and Braunston and Blisworth on the Grand Union Canal. ‘Second generation’ tunnels were built to augment the capacity of the existing ones: firstly Telford’s tunnel alongside Brindley’s at Harecastle, and finally the last tunnel to be dug in the canal age, Netherton Tunnel which was opened in 1858. With its twin towpaths, gas lighting throughout and navigable width of 17 feet, Netherton was intended to alleviate the pressure on the narrow Dudley Tunnel and duly became one of the busiest routes in the Birmingham area.

^{Photo: Air shaft in Netherton Tunnel. Photo by Peter Evans.}

In most cases the method of construction was by digging vertical shafts down to the required level from above and then working sideways from the shafts, using them to remove the spoil. Some of the shafts would often be left for ventilation. The ‘cut and cover’ method was used In a few cases where ground conditions were particularly difficult, notably Foulridge Tunnel.

The most well-known technique of propelling boats through tunnels is legging, whereby boatmen lay on boards across the boat and walked along the tunnel walls or roof. A range of other methods was used, including poles or shafts, chains or rails, towpaths in a few tunnels, and later steam or electric tugs. An unusual system was devised by Thomas Brewin for the long, narrow Lapal Tunnel on the Dudley No 2 Canal. A pump and stop locks at each end were used to create a current to push boats through in either direction, halving the transit time from 4 hours to 2 hours. The system proved effective and continued in use from 1841 until shortly before the tunnel was closed in 1917 after a collapse.

Facts and Figures

At the time of publication in 1976 of the definitive John Gagg’s Book of Canal Tunnels there were 46 tunnels still in use, 5 tunnels that had been opened out, and over 40 disused tunnels including the four longest ever built. Interestingly there were also two on now-abandoned canals that had never been used. The Salisbury and Southampton Canal was planned to connect with the River Itchen through a tunnel at Southampton, but despite John Rennie being called in the works were never finished. The 1,250-yard Southnet Tunnel on the Leominster Canal was completed but collapsed in 1795 before the canal was opened the following year, and was never repaired.

Like the earliest canal tunnel, the longest and largest canal tunnel built to date is in France. The Rove Tunnel was opened in 1927 on the Canal de Marseille au Rhône, connecting Marseille to the River Rhône. It is almost 7,800 yards long, 72 feet wide and 27 feet high, with a water depth of 13 feet. After a partial collapse it was closed in 1963.

Restoration

Happily the situation since John Gagg wrote has improved, with the reopening of two significant tunnels. Standedge Tunnel on the Huddersfield Narrow Canal is the longest canal tunnel built in the UK at 5,698 yards, having taken 17 years and over £120,000 to construct. It is also the highest above sea level (644 feet) and the deepest underground (more than 600 feet in places). It was officially closed along with the rest of the canal in 1944, although Robert Aickman, Tom Rolt and senior IWA members famously made a difficult passage through it on ‘Ailsa Craig’ in 1948. After a £5 million project it reopened in May 2001 as part of the restoration of the entire canal. For the first few years no internal combustion engines were allowed and visiting narrowboats were towed through in convoys by an electric tug which also acted as an observation boat for the crews. Despite the provision of rubber sheets to cover boats, they were liable to be damaged in transit, and when one of the tugs needed substantial repairs British Waterways carried out a trial run for self-steer operation. Since 2009 boats have been allowed to travel through the tunnel under their own power. Numbers are limited, advance booking is needed, and a CRT chaperone travels on the boat with a service vehicle following through a parallel disused railway tunnel.

^{Photo: Standedge Tunnel on the Huddersfield Canal. Photo by Bob Haigh.}

In addition the 696-yard Falkirk Tunnel on the Union Canal in Scotland was restored as part of the Millennium Link, a project to restore the Union Canal and Forth and Clyde Canal which joined them by means of a new short tunnel at Roughcastle and the Falkirk Wheel boat lift.
There are plans to restore or bypass other tunnels including the 3,817-yard Sapperton Tunnel on the Thames and Severn Canal. Passage through this tunnel is described vividly by C. S Forester in his 1953 historical novel Hornblower and the Atropos, when Captain Horatio Hornblower helps with the legging. Meanwhile the Lichfield & Hatherton Canals Restoration Trust is progressing an ambitious fundraising programme led by David Suchet, to build new tunnels under the new Lichfield Southern Bypass as well as the Cross-City railway line from Lichfield to Birmingham.

New Uses for Old Tunnels

There are several examples of unexpected new uses for both operational and derelict tunnels.

Greywell Tunnel on the Basingstoke Canal was closed in 1932 after a roof fall. It became a well-used home for bats and is now the site of Europe’s largest bat colony, with as estimated 12,500 bats of at least five species.

^{Photo: Eastern Portal of Greywell Tunnel. Photo by John O’Hare}

Perhaps surprisingly, the second longest tunnel after Standedge was Strood Tunnel on the Thames and Medway Canal in Kent. The canal was envisaged as a short (7-mile) passage between the Rivers Thames and Medway for both naval and commercial craft, avoiding the much longer journey around the Hoo Peninsula. The major engineering challenge was the chalk ridge of the North Downs, which was met with a tunnel of notable dimensions. Strood Tunnel was 4,012-yards long, completely straight, and the widest of all UK tunnels at 30 feet including a 6-feet wide towpath. Owing to the solidity of the chalk, no lining was needed, and as a result the exposed chalk reflected light so well that it was never completely dark in the tunnel during daytime. It was only wide enough for one barge and so there was a timed entry system. The tunnel soon became a bottleneck and a 150-yard section was opened out to create a passing place, resulting in two separate tunnels (the Higham Tunnel at the northern end and the longer Strood Tunnel at the southern end). When the railways arrived the Gravesend & Rochester Railway was built parallel to the canal along its length. Remarkably the single railway line shared the canal tunnel, partly supported by the towpath and partly by wooden piles driven into the canal bed. The sight of barges and trains running side by side within the tunnels must have been spectacular, but it only lasted for a couple of years before the decision was made to create a double-track railway. The canal bed within the tunnels was filled in and converted to a railway line in 1847. The tunnels are still in use and can be traversed on trains on the North Kent Line between St Pancras International and Margate – and viewed from both Higham and Strood stations.

^{Photo: Higham Tunnel. Phot by John O’Hare.}

The Union Canal between Edinburgh and Falkirk has links with the murderers Burke and Hare, who came from Ireland as navvies to work on the canal between 1818 and 1822. They subsequently killed 16 people to earn money by selling fresh corpses for medical experimentation at Edinburgh University. When the canal was restored a new LED lighting system was installed in the Falkirk Tunnel which reveals details including candle-holders, dynamite stores and shafts, and lends itself to artistic and theatrical events. In August 2017 the tunnel became a pop-up theatre venue for a play about Burke and Hare called “The Resurrection”, in a collaboration between Scottish Canals and The Walking Theatre Company.

On a much more upbeat note, Dudley Tunnel is probably unique among canal tunnels in being licensed for civil weddings. The bride arrives on a Dudley Canal Trust tug and the ceremony is performed in the Singing Cavern, with room for 50 guests on land and a further 50 on a boat.

_{Photo-top: Shrewley tunnel, Grand Union Canal, Dawn. Photo by Robert Silverwood}

The word aqueduct is thought to have first appeared in the 16th century, as the Latin aquaeductus. It is from ‘aqua’ water, and ‘ducere’ to convey. Appropriately Roman, as Romans were the master exploiters of aqueducts.

Early Aqueducts

Crete has early examples of simple water channelling systems from the Minoan period. Similarly, Egypt & China both had their quanats to carry water underground. The first long-distance canal systems were constructed by the Assyrians in the 9th century BC.

In the 7th century BC Assyrian king Sennacherib constructed a wide canal with a 920ft (280m) long white stone ‘bridge’ to bring water to Nineveh. The Jerwan aqueduct is acknowledged as the first large above-ground aqueduct.

The Greeks then got in on the act, with places like Athens being supplied by long distance aqueduct systems in the 6th century BC.

Roman Aqueducts

When in Rome, what did the Romans do? Some Roman aqueducts are still in use in Rome today! They provided drinking water to inhabitants – a million of them at its peak – up to 1 cubic metre (1 tonne) each every day. This is about five times what we in the UK use on average today. The Roman aqueducts not only provided drinking water for the Romans but also supplied the bath houses with ample water. Others acted as indoor sewer systems that carried water away from the city. The water flowed and emptied by gravity into giant cisterns in the city, distributed by lead pipes to most parts.

The invading Goths and Visigoths knew the importance of water supplies to Rome, and systematically destroyed them. The structures were not put back into use until the Renaissance period.

canal aqueducts in Britain

Brindley’s Barton Aqueduct

Completed in 1761 and opened on 17th July to cross the River Irwell, this was the first canal aqueduct in Britain. The stone aqueduct was about 600’ in length and 36’ in width at the top, the waterway being 18ft (5m) wide and about 4 1/2ft (1m) deep carried in a puddle channel across the structure. James Brindley is said to have ‘retired to his bed for several days’ when it opened, as it sagged a bit. However it was still in good condition when replaced in 1893 by the Barton Swing Aqueduct. Designed by Sir Edward Leader Williams when constructing the Manchester Ship Canal, it is still going strong today.

The aqueduct was high and finely built, to leave space for the Mersey and Irwell Navigation boats to pass. Perhaps as a result of the sagging, Brindley’s aqueducts from then on were very squat and massively constructed, as can be seen in his longest remaining one carrying the Trent and Mersey Canal over the River Dove, north of Burton on Trent with its 23 arches.

Royal Gunpowder Mills

The Royal Gunpowder Mills in Waltham Abbey had their own canal system. It began with the Millhead Stream, used for the smooth and safe delivery of raw materials and collection of gunpowder. This finally extended to a system over 5 miles long linking all the buildings involved in making gunpowder.

The cast iron aqueduct was one of two aqueducts built in 1878-9 to carry the extended high level canal system over the natural waters of the original River Lea. Both these aqueducts are made from three huge cast iron plates (the base and two sides) brought by barge and then lifted and riveted on site. There is a third aqueduct near Newton’s Pool of a slightly different design. There are only 26 cast iron aqueducts in Britain. Three of these are in the Gunpowder Mills.

Telford’s first Iron Canal Aqueduct

The Shrewsbury Canal was originally constructed with Josiah Clowes as Chief Engineer, however he died in 1795 part way through construction. Thomas Telford, who was at the time Shropshire’s County Surveyor and already engaged on the Ellesmere Canal, took over.

One of Telford’s first tasks was to rebuild a stone aqueduct over the River Tern at Longdon-on-Tern. It had been built by Clowes but swept away by floods in February 1795. Telford originally intended to replace like for like. However the influence of Shropshire Ironmasters such as William Reynolds in the Shrewsbury Canal Company may have led Telford to jointly design the simple cast iron trough with Reynolds. The design used cast iron trough sections from Reynolds’ Ketley ironworks bolted together on site in 1796. The main trough was 62 yards long (57m), 7.5ft (2.3m) wide and 4.5ft (1.4m) deep, with a half height narrower trough to one side which formed the towpath.

The aqueduct was the world’s first large-scale iron navigable aqueduct, though it was narrowly beaten by a much smaller 44ft long (13m) structure on the Derby Canal built by Benjamin Outram.  The Derby Canal aqueduct itself was removed from site for safe keeping when the canal was filled in by Derby City Council, however the ironwork went missing possibly scrapped during a clearout. Never throw anything away!

The largest aqueduct in Britain

Pontcysyllte Aqueduct, designed and built by Telford and overseen by Jessop, is the largest aqueduct in Britain. It is 1,007ft long and carries the Llangollen Canal (originally the Ellesmere Canal) over the valley of the River Dee. It is constructed of local stone with a cast iron trough 11ft 10in (3.6m) wide and 5ft 3in (1.6m) deep which extends under the towpath.  The aqueduct holds 1.5 million litres of water and takes two hours to drain.

The pillars were constructed to a hollow and tapered design, to reduce the overall weight of the structure and size of the pier foundations.  Mortar used was mixed from ox blood, lime and water and the sealant for joining the cast iron aqueduct plates from Welsh flannel and a mixture of white lead and swarf from boring waste. Begun in 1795 it was completed in 1805 and cost a total of £47,018 6 shillings and 7 pence. ‘Pontcysyllte’ means “Cysyllte Bridge”.

Stratford Canal’s Edstone Aqueduct

Edstone Aqueduct, Stratford Canal. Photo by Dr Neil Clifton

The 475ft (145m) Edstone Aqueduct is the longest aqueduct in England. It takes the Stratford Canal over the tracks of the former Alcester Railway line. Locomotive firemen would often top up their boilers via a convenient pipe feeding down from the aqueduct!

The Canal Network’s First Ancient Monument

Rennie’s Dundas Aqueduct carries the Kennet & Avon Canal over the River Avon and the Wessex Main Line railway from Bath to Westbury, near Limpley Stoke in Wiltshire, England. It is named after Charles Dundas, the first chairman of the Kennet and Avon Canal Company.

Closed in 1954, for a while in the 1960s and 1970s the canal was dry and it was possible to walk along the bed on each side of the river as well as through the aqueduct itself. The aqueduct was relined, with polythene and concrete and restored, reopening in 1984.

It is Grade I Listed, and the first canal structure to be designated as a Scheduled Ancient Monument in 1951.

And the most elaborate aqueduct?

The aqueduct carrying the Engine Arm over the Birmingham Main Line was one of the later cast iron examples. It is a single span cast at Horsley Iron Works. It is ornately decorated with a gothic ‘blind arcade’- a series of pillars linked by arches. Painted as it is today, this looks very impressive.