H         Dams

Canal dams are of more significance when considered as part of an overall canal scheme than as isolated structures significant in the history of technology. Outside the world of artificial navigations the first known dam was built near Helwan, some 20 miles south of Cairo at a date between 2950 and 2750 BC.⁷⁴ This was built to create a reservoir for irrigation purposes in the Wadi el-Garawi with a crest length of 106m and a base length of 81m, and a maximum height of 11.3m. Twin dry-stone masonry walls, each 24m in thickness, had a core of gravel 36m in thickness. Substantial remains of this structure have a gap in them 46m across with a lack of silt, suggesting a wash-out of the unmortared structure soon after construction.

Until the 19th century dams were of massive construction, using the weight of the structure to counteract the force exerted by the water contained. It was in France that the theory of the lightweight arched dam evolved, making the construction of dams easier and quicker, although by this time most dams were provided for non-navigational purposes. The Rideau Canal in early 19th-century Canada consisted partly of lakes created behind arched dams (notably at Jones Falls).

French engineers built an arch dam on the Rio Grande, 11.6m high and 2.35m thick, in 1888 as part of their work on the Panama Canal. The arch design was not to influence European dam construction until later, but this type of dam was soon widely built in North America and Australia.⁷⁵

S I T E S

i	Alresford Dam, Itchen Navigation (UK), built 1189-1200 (see "Reservoirs").
	The water from two small streams is contained by an earth embankment 76m long, 18m thick at its base and 9m at its crest, with a maximum height of 6m. The dam is now overgrown and, owing to the formation of swallow holes, the reservoir now holds back 24ha of water rather than the original 80ha.

ii	Grand Canal Dam (China), second water-feeder dam built (see "Reservoirs").

iii	St Ferréol Dam, Canal du Midi (France), built 1667-1671.
Grading: 1. *; 2. ***; 3. ***; 4. *. Total: 8
	Built on the first heavily engineered, and hugely influential, canal of the modern period (see "Canal du Midi" in Section 3). To the north of the canal's summit, suitable sources of water were found in the rivers of the Montagne Noire, the only drawback being that more water than was needed was available in the winter, and less in the summer. Pierre-Paul Riquet therefore took the logical step of building a reservoir to store the surplus winter run-off for use during the following summer. The dam of St Ferréol was built across the river Laudot about 2 miles south-east of Revel. A wide and shallow valley and the availability of suitable materials allowed Riquet to build an earth dam of impressive size, holding 5400 acre-feet capacity. The dam of St Ferréol is 780m long at its crest, has a maximum height of 32m above the river-bed, and at the centre has a base thickness of more than 137m. Two low masonry revetment walls flank an earthen core, capped in clay, which encases a full-height central wall. All three walls penetrate into bedrock for a depth of 3-4m.76 The 18th-century (1777-81) masonry buttress dam on the Canal du Midi feeder system at Lampy is also of some significance and was the second of its type to be built in Europe. In fact the whole water supply system, which extended about 15km from the dam to the canal, is of considerable significance.

Figure 6 Jones Falls Dam, one of a series erected to create large sheets of navigable water along the line of the pioneering Rideau Canal, Ontario (Canada), 1826-32

iv	Jones Falls Dam, Rideau Canal, Ontario (Canada), 1826-32. [Figure 6]
Grading: 1. **; 2. **; 3. ***. Total: 7
	The Rideau Canal was a canalized waterway consisting largely of channels linking a series of lakes artificially created and heightened by the construction of some 52 dams and embankments in the Canadian wilderness. The highest is at Jones Falls, located 43km north of Kingston, at the junction of Sand and Whitefish lakes, where a 2.5km long set of rapids fell 18m, the largest drop between Ottawa and Kingston. The dam rises 19m from a narrow rocky ravine and was double the height of any other dam existing in North America at that time. The dam measures 107m along its crest, which curves to a radius of 53.4m and is arched in plan and concave in profile, thus giving the appearance of a true arched dam. The ratio of base width to height of 0.44 falls short of the minimum accepted ratio for a gravity dam and may explain why the Royal Engineers strengthened its upstream side with a considerable earth bank extending beyond the clay-puddled core. The dam survives in very good condition and is maintained by Parks Canada.77

 

I         Weirs

The submerged type of low dam with water continually flowing over the top, known as a weir, was also quite important. Weirs were a major feature of river navigations. Needle weirs, developed from flash-lock technology, can still be found on navigable rivers in central and southern France and on the Naviglio Grande in Italy; they have disappeared from northern Europe because they are difficult to operate in icy winter conditions. Weirs have often been rebuilt as water-flow conditions and demands have changed. However, some old weirs still remain. At Gathurst, near Wigan (UK), one of the weirs of the Douglas Navigation still survives. A stepped stone weir, built in 1741, the navigation ceased operation in the 1780s, though this weir was needed for access to colliery wharves by boats passing through a lock between the canal and the river. It was probably isolated and taken out of use in the 19th century. For weirs on the Vltava (Czech Republic), see "Rafting."

 

J         Overflow weirs

Canals, despite their main use as navigable channels, are also an important feature of land drainage. During wet weather their water-levels rise, which could result in breaching of the canal banks. Overflow weirs are a vital stabilizing device which keeps water-levels in artificial channels at the height required.

The first recorded use of these was in ancient China. Early examples were set in the Kuanhsien Irrigation System and the Ling Chhu Transport Canal. In Sung Period texts the terms shih- to and shui-to were mentioned many times, often in connection with the Pien or Grand Canal, which in some sections had rows of ten or thirteen spillways, one after the other, along it. Side sluice stop-log gates (cha) were in common use for the rapid evacuation of flood water.⁷⁸

Perhaps the most famous overflow weir was that which was originally installed at Castlefield, Manchester (UK). It was of clover-leaf formation, an optimum design as the volume of water which an overflow weir can handle depends upon its length. Using a clover-leaf shape maximized the length of the overflow, but kept the area it occupied to a minimum. The water passing over the weir drained into the river Medlock through a shaft and tunnel built in the centre of the clover-leaf. Unfortunately it has been rebuilt to a more standard design.

 

K         Outlet sluices

Any artificial waterway had to have a mechanism by which it could be quickly emptied in the case of a breach, flood, the sinking of a vessel, or for purposes of cleaning.

The early terminology of ancient Chinese canals is complex, but some names used such as shih-tha-yen (stone gate dam) suggest heavy sluice drainage gates: this particular dam impounded the Khun-ming Chhih Lake south-west of Chhang-an, a stretch of water created in 120 BC for naval combat exercises. The same term is used later, as at Haichow in AD 1020 when Wang Kuan-Chih wanted to take water from such a spillway dam for the Grand Canal. Smaller-scale culvert spillways (tung), of stone, 3-4ft square, were often placed at suitable heights in the embankments enclosing a canal.

An emergency release sluice was also an early development in China. A pa (flying dyke) was a very long shallow U-shaped spillway with a stone revetment and masonry cheeks, running along the bund of a canal or lake. Usually this was full of reed bundles, fascines, earth, etc, forming part of the embankment. In times of emergency a small breach could intentionally be made in the centre of the fill, whereupon the force of the water would quickly wash it all away, flood and debris discharging together through previously prepared channels. Eleven flying dykes of this kind, built between 1680 and 1757, in the defences of the Hung-Tse Hu (lake) and the Grand Canal, measured an average length of 122m and an average height of 2.75m.⁷⁹ Good examples of these need to be identified on the Grand Canal if possible.

Many later canals were provided with drainage sluices, built into the bed of the canal, which drained into culverts passing under the canal. On 18th and early 19th century canals, the plugs which sealed these drains were made from wood and were hinged. An iron chain was attached which allowed them to be raised, thus draining the section of canal. Groves were provided at bridges and other points into which wooden stop-planks could be inserted. This ensured that only short sections of canal needed to be drained, and helped to conserve water. A good example can be found on the Manchester, Bolton and Bury Canal (UK), next to the Clifton Aqueduct.

Stop planks were also provided at either end of embankments or at places where the canal was in danger of breaching, such as in coal-mining areas throughout Europe. In some cases, automatic gates were built in their place, such that when there was a breach, the flow of water would close the gates and thus save water and damage. Examples can be seen on the Leeds and Liverpool Canal, Burnley (UK), although they are not now in use.

Culverts into which the canal drained were often used for allowing streams to pass under the canal. They were also built specifically for this purpose. If they were not built, the construction of the canal would interfere with land drainage, the land on the higher side of the canal becoming inundated. This could cause failure of the canal banks.

 

L         Accommodation bridges

These are a very common type of feature, to accommodate existing tracks, roads, and rights-of-way and to connect lands divided by the new waterway. The outstandingly important Grand Canal in China has some particularly elegant large stone-arched examples. The historic Canal du Midi by contrast had 139 road bridges over its course, which are of surprisingly modest dimensions and with a towing-path underneath that is not large enough for a horse.

Most of these 17th-century stone-arched bridges have a height from water-level to the underside of the crown of the arch of 3.25m (10 ft 91 in), not much larger than the later typical broad-canal bridges used in the Industrial Revolution in Britain. However, the over-bridges on any canal could be a mixture of stone- or brick-arched bridges and draw (lift) and swing bridges. Many British canals in the Industrial Revolution were originally built with lifting or swing bridges. Arch bridges replaced them as road traffic increased during the late 18th and 19th centuries.

One important development of the canal age in Britain and Ireland was the skew bridge, first introduced by Chapman in 1808 on the Naas branch of the Grand Canal in Ireland. In a conventional bridge the arch is at right-angles to the canal and springs from a flat bed. In a true skew bridge, the arch is not at right-angles, so the beds of the arch are not directly opposite each other, but are slightly staggered along the line of the canal. The bed of the arch is also angled from the horizontal so that the forces act through the centre of the bridge. Brick bridges built on this principle are now widespread, and one can be found on the main line of the Grand Canal (Ireland), near Sallins, where the canal to Naas branched off. Unfortunately, the original ones have been rebuilt. Angled bridges were also built using a conventional right-angled arch, but with additional angled stone or brickwork at each side of the bridge. A typical example can be seen at Eanam Wharf, Blackburn (UK), built in 1810, on the Leeds and Liverpool Canal, though there are other examples throughout the British canal system. Such angled bridges are not as strong as a true skew arch because the forces do not act through the centre of the bridge.

Later came iron-girder and iron-arch bridges. There was a "Bridge of the Iron Window Lintels" built over a water-course in China about AD 1000, and the first known cast-iron bridge in the modern world, the Iron Bridge in Shropshire (UK), now part of a World Heritage site, spanned the navigable river Severn. The first iron bridge over a navigable canal was appropriately one of those built in the then iron-smelting centre of the world in Merthyr Tydfil, Wales (UK), for the opening of the Glamorganshire Canal in 1794. The Coalbrookdale Company cast two overbridges for the opening of the Kennet and Avon Canal in 1800; these are sited in the 18th-century Sydney Gardens in the World Heritage Site city of Bath. Telford also built two composite bridges with iron ribs supporting shallow stone-arches at the Trefor Basin to the north of the Pontcysyllte Aqueduct in 1805.

S I T E S

i	Notable overbridges on the Grand Canal (China).
Grading: 1. * 3. ***; 4. **. Total: 6
	There are a large number of high-arched masonry bridges surviving along the line of the Grand Canal.

ii	Original overbridges on the Canal du Midi (France).
Grading: 1. *; 2. *; 3. ***. Total: 5
	The features of this canal inspired succeeding developments on waterways of the modern period.

iii	Rhyd-y-car Iron Bridge, Glamorganshire Canal, Merthyr Tydfil, Wales (UK), 1790-94.
Grading: 1. ***; 2. ***; 3. **; 4. *. Total: 9
	Erected by the local engineering genius Watkin George in 1790-94 in what was then the world centre of the iron industry. This was the first iron-girder bridge in the modern world. The sides of the bridge are single rectangular castings with two intermediate uprights and an enclosed arch with radial struts. Lobes underneath formed mortises for the tenons of the deck girders (now renewed) in a continuance of the use of woodworking-type joints by the earlier builders in cast iron. The bridge has been resited with other conserved canal remains at Chapel Row, Georgetown, Merthyr Tydfil. This bridge with Pont y Cafnau (see "Aqueducts") forms part of the integrated industrial landscape of Merthyr Tydfil that has already been considered by TICCIH as one of the 28 industrial sites of outstanding international importance.

iv	Sydney Gardens overbridges, Kennet & Avon Canal, Bath (UK), 1800.
Grading: 3. ***; 4. *. Total: 4
	Cast in 1800 by the Coalbrookdale Company to span the canal in this elegant 18th-century pleasure garden, now part of the World Heritage city of Bath. One of the bridges is a footbridge of about 7m span and 3.05m width, with cast-iron deck and railings supported by four arched ribs, cast in two sections with compressive rings in the spandrels. The bridge was restored in 1978. The second bridge crosses the canal at an oblique angle in spans of over 9.15m (30ft) and carries a 5.8m (19ft) wide roadway. The face ribs are solid panelled in two sections and there are five interior ribs of T- or +- section carrying 3.05m (10ft) wide deck plates set parallel to the canal. The cast-iron parapets have diamonds superimposed on crosses.80

v	Trefor Basin overbridges, Ellesmere (Llangollen) Canal, Trefor, Ruabon, Wales (UK), 1805.
Grading: 2. *; 3. ***; 4. *. Total: 5
	Thomas Telford took advantage of the new adjacent Plas Kynaston Foundry where William Hazeldine was casting the deck of the Pontcysyllte Aqueduct in 1805 to produce cast-iron arched ribs to support the elegant segmental arches of masonry of the two canal overbridges at the north end of the aqueduct. Both bridges still carry public roads.

vi	Galton Bridge, Birmingham Canal (UK), 1827-30. [Figure 7]
Grading: 2. *; 3. ***; 4. *. Total: 5
	The deep cutting proposed by Telford for the new low summit-level of the Birmingham Canal Navigation necessitated the use of the early type of large-span cast-iron arched-bridge developed by Telford in association with the ironfounder William Hazeldine. This was in order to carry a road across the canal. This remained in use for traffic until 1974 and the bridge has been retained as a footway. The bridge is flanked by huge, finely detailed, stone and brick abutments standing on the upper slopes of the deep cutting (see the new Birmingham Canal mainline in "Technologically significant canals").81

Figure 7 The substantial 46m cast-iron span of the Galton Bridge carries an 8m wide earlier public road over the 22m deep new canal to Wolverhampton: Birmingham, England (UK), 1827-30

 

M         Tunnels

The civil-engineering technology applied to canal tunnels was not an innovation: Roman water-supply and lake-drainage tunnels of quite large section were not uncommon. That built in AD 41-52 to drain Lake Fucino was 5.5km long and 6m high and had some 40 construction shafts on its line. The surviving Cloaca Maxima draining the Forum area of Rome (a World Heritage site) was large enough to take boats used in periodic cleaning of the silt. There were even Roman road transport tunnels. One such carried traffic through the Posillipo Hill between Naples and Pozzuoli. It was driven through tufa bedrock and was 915m long and 7.6m wide. To try and admit light to the interior, the roof and floor converged towards the middle from the portals, which are no less than 23m high. It is thought to date from the time of Augustus (31 BC-AD 14).⁸² Tunnels used by boats led into the city of Damascus from the river.

The Canal du Midi was the first heavily engineered summit canal of the modern age and enormously influential in the construction of waterways during the world's first Industrial Revolution. The Duke of Bridgewater saw the large Malpas tunnel on the Canal du Midi and was inspired to build the first heavily engineered modern canal in Britain, which terminated in canal systems at both ends.

The British canal network was notable for the extent of tunnelling needed to adequately serve the upland districts at the heart of the Industrial Revolution. The origin of this use may have been in flooded mining tunnels or "levels" where boats were used as a convenience on the large amounts of mine drainage water. One such at the then world copper-smelting centre of Swansea, Wales (UK), was constructed to supply coal to a new copper smelter constructed in 1748 and was reported on by the Swedish industrial spy Svedenstierna in 1803-04. At the Worsley Collieries end of the Bridgewater Canal (1759-60) the waterway was tunnelled into a hill for a at least a mile to drive directly into colliery workings. By 1878 it extended for a total of 40 miles underground on three levels connected by winding shafts and an inclined plane, and this well publicized system was widely copied in Britain and on the mainland of Europe.

At the Bridgewater Canal's other terminus in Manchester it terminated in a tunnel under Castle Hill, from whence coal was wound up for sale via a vertical shaft. A second longer tunnel of this type was added later.

While working on the Bridgewater Canal, its engineer, James Brindley, agreed to carry out a much larger canal, the Grand Trunk, traversing the centre of England to connect the large Trent and Mersey rivers. Near the middle, just north of the potteries at Stoke-on-Trent, was the Harecastle Ridge. This was the first intermediate tunnel on a British canal (1766-77) and the first large-length tunnel on any waterway in the world, and Brindley's opponents saw it as evidence of his insanity. More details of this work are given below. It is now impassable, as are the earlier Worsley mine tunnels, but still accessible are the slightly later (1775-92) Dudley limestone mining canals and associated Dudley Canal Tunnel, near Birmingham (see description below).

Some large waterway areas are characterized by a low use of canal tunnelling activity, notably India and North America, with only one substantial canal tunnel built in each. However, the unfinished Marshall canal tunnel on the Kanawha Canal in the USA provides a valuable time-capsule of 19th-century tunnelling methods.

S I T E S

i	Malpas Tunnel, Canal du Midi (France), 1681-83. [Figure 8]
Grading: 1. ***; 2. ***; 3. ***; 4.*. Total: 10
	Built as part of the first heavily engineered summit canals of the modern age, this was the first navigable canal tunnel built and the first tunnel to be excavated by gunpowder, the use of which represented a most significant advance in rock tunnelling. Situated at Malpas, about 6 miles from Béziers, the tunnel is 157m long, 6.7m (22ft) wide, and 8.2m (27ft) high. After two years' work it was finished in 1681 and arched some ten years later.83 Some 15.5m beneath is an earlier tunnel into which a shaft drains. This was built to drain the Étang de Montardy in 1247 and is an underground water-drainage culvert 1.5m (5ft), 2m wide, and 1360m long which is still in use.84

ii	Worsley Colliery Canal Levels, Bridgewater Canal, Lancashire (UK), 1759-.
Grading: 1. **; 2. ***; 3. ***; 4. **. Total: 10
	This is the largest and earliest internationally known example of the extensive use of canal tunnels in a mine and it is important for being part of the most influential canal built as part of the Industrial Revolution (see "Technologically significant canals"). The entrance basin, surrounding quarry faces, bridges, and tunnel entrances are conserved and protected monuments.

iii	Harecastle Tunnels, Trent & Mersey Canal, Stoke-on-Trent (UK), 1766-77 & 1825-27.
Grading: 1. *; 2. ***; 3. ***. Total: 7
	Built 1766-77 by James Brindley, the first intermediate tunnel on a British canal and the first intermediate long-length canal tunnel (2635m long) in the world. Excavation was effected in both directions from a number of shafts sunk to the tunnel's course, the spoil being loaded into buckets that were drawn up the shafts by horse-powered windlasses (horse gins). A new technology of civil-engineering pumping was being deployed. First, wind- and water-driven pumps were installed to deal with the small quantities of water that were encountered. As the shafts penetrated deeper into the hill, water was met with in quantities sufficient to drown the bottom of the shafts, and also methane gas, which made working difficult. Only 374m of canal were driven in two years. Consequently windmill-driven ventilation was introduced and a Newcomen atmospheric (early low-pressure) steam engine was erected to pump the shafts dry. However, Brindley had known of the high water-table and relied on it to feed the summit-level of the new canal. Contemporaries called it "the eighth wonder of the world," and after Brindley's death in 1772 it was completed by his brother-in-law Hugh Henshall. It was 2.7m (9ft) high and 2.7m wide. Coal was found during the driving of the tunnel and side tunnels were driven along the coal seams at right-angles, so that 10-tonne boats could bring the coal out. In 1827 Thomas Telford opened a larger parallel tunnel which had a horse towpath and one-way traffic was introduced on both tunnels. Subsidence is now affecting Brindley's tunnel and only Telford's is still in use.85 Both tunnels are important in illustrating the early and progressive development of canal tunnelling technology.

Figure 8 The first known canal tunnel at Malpas, Béziers, Canal du Midi (France), 1681-83

iv	Dudley Limestone Mining Canals and Dudley Tunnel, near Birmingham (UK), 1775-92
Grading: Grading :2. *; 3. ***. Total: 4
	Parts of the mining system are maintained and are accessible by special trip-boats, and the main canal tunnel has been consolidated as part of the main canal system. Lord Ward's Canal was built from Brindley's adjacent Birmingham Canal in 1775-78 and penetrated through a 206m tunnel to terminate in underground limestone workings. The main canal tunnel that absorbed this was commenced through the 2.8km to the Dudley Canal in 1785-92. The 4.3m (14ft) high, 2.7m (9ft) wide tunnel was constructed with Abraham Lees as resident engineer and Thomas Dadford Senior (who had worked with James Brindley) as consultant. By 1790 two areas of limestone workings had opened up parts of the tunnel and a branch canal had been built along one of the limestone beds. This eventually extended for three-quarters of a mile with junctions, tramways, passing bays, and even a roving bridge. This is the system still accessible via a new section of tunnel. Among other canal branches is the 1084m tunnel driven westward to limestone mines under Wrens Nest Hill.86

v	Saint Quentin (Le Grand Souterrain de Riqueval), Canal de St Quentin (France).
Grading: 1. *; 2. *; 3. ***. Total: 5
	The tunnel at St Quentin is 5670m long and was opened in 1810 by Napoleon I. Until 1864, boats were moved through the tunnel by gangs of seven or eight men. In 1864 chain towage was introduced, the chain tug using a horse gin built on board to pull the tug and vessels in tow. From 1874, steam-powered chain tugs were used, and these were replaced in 1910 by electrically powered chain tugs, which are still operating. During World War I the tunnel was used as a hospital, with additional side tunnels being built to accommodate the wards.

vi	Marshall Canal Tunnel, Kanawha Canal, Virginia (USA).
Grading: 3. ***; 4. *. Total: 4
	The Kanawha Canal's Unfinished Division from Eagle Rock to Buchanan in Virginia was begun in 1851 and abandoned in 1856, leaving locks, culverts, aqueducts, and tunnels in an incomplete state. The unfinished 571m long Marshall Tunnel, like the rest of the canal, is a valuable time-capsule on canal construction strategy. There were three intermediate shafts to provide ventilation and from which construction could proceed. That on the east was in part at least a natural sinkhole (this is now filled with clay). The central shaft was some 30m deep and construction in the two headings at the bottom proceeded for about 41m (the shaft is now infilled). The western shaft is shallower and only about 30m from the mouth of the western heading, from which some 64m of tunnel was driven. From the east heading 138m of tunnel was driven as far as the natural eastern shaft. The processes of tunnelling with hand drills and black powder are clearly illustrated by this untouched time-capsule. Most of the canal remains were designated the Upper James Scenic River by the Virginia General Assembly in 1985.87

 

N         Cargo handling

The ease of loading and unloading cargoes from inland vessels is one of the most important factors in the decision to send goods by water. Treadmill cranes were often used on early waterways, the example at Gda_sk (Poland) also being used for removing and fitting the masts of sailing ships. Several examples of smaller treadmill cranes can be found alongside German waterways, in Lüneburg, Stade, Würzburg, and Rüdesheim. Trier (Germany) retains two large cranes on the banks of the Moselle (see below). Small cast-iron-framed cranes can be found in many places, particularly on the British canal system (one at Worsley on the Bridgewater Canal). Steam-powered cranes are also widespread across Europe. More unusual, and particularly noteworthy, is the compartment boat hoist at Goole (UK). The last remaining of five such hydraulically powered lifts, it unloaded specially built coal carrying compartment boats. The system was in use from 1863 to 1986. When the Dortmund-Ems Canal (Germany) was being designed in the 1880s, the system was studied, though not used. A similar, but more developed, system of compartment boats was used on waterways linked to the Mitteland Canal (Germany) between 1941 and the 1980s.

S I T E S

i	Trier Cranes, Rhineland-Palatinate (Germany), 1413 & 1774.
Grading: 3. ***. Total: 3
	Trier was a capital of the western Roman Empire, situated on the navigable river Moselle. The river was always important to the wine trade and two old cranes, dating from 1413 and 1774, survive on the river bank at Trier that were largely used for loading casks of wine. Both are sited in squat circular masonry towers with high conical roofs constructed in two sections. The upper, turning, sections each have two angled 13m long jibs protruding. These could be used both to serve boats on the river and the road on the bank simultaneously. Each crane was powered by two treadwheels, 4.2m in diameter and 1.2m wide.88

 

O         Warehouses

Warehouses of one sort or another to hold high-value and perishable goods must be a building type as old as inland, coastal, and maritime shipping itself. One particularly notable range of warehouses was arranged round the Roman Emperor's great new octagonal port basin at Portus, west of Rome. All canals built in the modern industrial period have warehousing provision.

In Europe, there are fine early (16th-18th century) examples of salt warehouses in Lübeck and Regensburg (Germany). Early merchandise warehouses can be found in the old ports, such as Hoorn and Harlingen, around the former Zuider Zee (now the _sselmeer) in The Netherlands. Although designed for Dutch East India Company trade, they were often alongside canals and were probably used in conjunction with the trekvaart system.

The development of warehouses following the Industrial Revolution in Britain is best illustrated by structural evolution in that country. Early examples of British warehouses have unsupported wooden beams. Later, to increase the width, wooden and then cast-iron columns were introduced. At first, no external awnings were provided so that cargoes were unloaded in the open.

A development of the late 18th century on British canals was the use of "boat holes" - large arched openings on the ground floors of warehouses that gave access to an internal boat-loading dock with a hoist to the upper floors. This type originated on the pioneering Bridgewater Canal at Manchester, where in 1765 the canal was extended underground by tunnel to give access to a haulage shaft up street level that was driven by a waterwheel operated by surplus water flowing out of the canal. In the 1770s a dry-goods warehouse was built by the canal engineer James Brindley over the mouth of the access tunnel; this winding shaft and the waterwheel were then adapted to drive the hoists in the new warehouse. Some canalside warehouses were the earliest such structures having railways going into them. They are described in the "Early railways" section below. External awnings began to be provided on canal warehouses generally following the stimulus to competition provided by railways in the later 19th century.

Steel and brick had replaced iron and stone as structural materials by the start of the 20th century, with concrete being used later. The warehouses of the Leeds and Liverpool Canal (UK), built between the opening of the canal in 1773 and the 1920s, exhibit all these features. Good examples of early 20th century warehousing can be seen in the Westhaven, Berlin (Germany) of 1914-1923, with its associated port administration buildings, and in the haven of Prague (Czech Republic). Both these sites had railway connections, as is usual in Europe for inland ports built after the late 19th century.

S I T E S

i	Bridgewater Canal Warehouses, Manchester (UK), 1770s; 1827-28.
Grading: 1. **; 2. ***; 3. **; 4. *. Total: 8
	The Manchester canal warehouses exhibit innovation in the introduction of internal boat unloading and the facility for goods movement from the waterways at the front through to cart loading at the rear.89 i.a Dry Goods or "Grocers" Warehouse, Castlefields, Manchester, 1770s. [Figure 9] Designed by James Brindley at the Manchester end of the Bridgewater Canal and extended in a large range eastwards by 1829. In 1960 much of the original building was demolished, except for the back and side walls, unloading basins and the shipping holes where boats drew in to be unloaded and originally continued to the vertical shaft where coal was hoisted to an upper coal wharf; the wheel-pit and underground channels for powering the warehouse and shaft hoist also survived. In 1986 this served as the basis for a partial reconstruction of the warehouse, waterwheel, and hoist.90 This site could be combined with any designation of the Bridgewater Canal (see "Technologically significant canals"). i.b-d Merchants' Warehouse, Bridgewater Canal, and other waterways warehouses at Manchester. The last intact early 19th-century warehouse to survive at the Manchester end of the Bridgewater Canal, it was built in 1827-28, mainly in brick. Two central high-arched shipping holes allow canal boats into the centre of the four-storey warehouse where an internal hoist could unload them. Four full-height loading bays on the front facade also facilitated external loading. Internally brick cross- walls both supported the floors and reduced the likely spread of any fire. The building has recently been renovated and entered re-use. The later, but still early 19th-century Middle Warehouse at Manchester has been renovated and converted to apartments. It retains a huge arch spanning the two former boat holes in the centre of the building. All these warehouses could also be combined with any designation of the Bridgewater Canal which they served (see "Technologically significant canals").91 The Old Quay Company's New Botany Warehouse of 1824, on the banks of the Irwell Navigation nearby, exhibits a mature use of cast-iron internal columns and could be grouped with these other Manchester waterways warehouses.92 This warehouse has also been recently renovated and entered reuse.

Figure 9 "Merchants" and Middle Warehouses, Castlefields Basin, Bridgewater Canal, Manchester, England (UK): part of a series of innovative late 18th and early 19th century warehouses with internal boat- unloading docks (prior to restoration)


 

P         Canal railways and railway/waterway warehouses

Most considerations of the railway heritage are preoccupied solely with the development of the modern locomotive railway, which is generally agreed to have started with the building of the Liverpool and Manchester Railway in 1830. However, railways were common underground in the Middle Ages in mines in the German-speaking areas of Europe. In 1603 the first substantial above-ground railway was constructed at Wollaton (UK) and from then until 1800 such lines were generally short transport ways connecting mines to the nearest navigable water. They were traffic feeders to the existing waterways, with which they formed an integrated transport system. Always horse-drawn, they developed considerably in sophistication in Britain during the period 1800-30, with experimentation in types of mechanical propulsion and iron track. Again they were generally part of a larger system based on navigable waterways. After the construction of the Liverpool and Manchester Railway in 1830 they spread world-wide as a more rapid arterial transport system that in many areas rivalled and even superseded water-borne transport in the later 19th century.

The interchange warehouses on early 19th century railways were important structures, not least because they form the first warehouses on railway systems. Even as railways became independent arterial systems of transport in their own right, interchange points still remained of great importance, especially with the larger canals bringing goods from abroad.

S I T E S

i	Railway Warehouses on and around the Brecknock and Abergavenny Canal, Wales (UK).
Grading: Grading: 1. **; 2. *; 3. ***; 4. *. Total: 7
	The Brecknock and Abergavenny Canal has a series of warehouses at interchange points with horse-drawn railways feeding traffic from nearby ironworks. These warehouses, all standing on canal wharves, are some of the earliest railway warehouses built. They are all part of one of the 28 industrial landscapes and sites already recommended by TICCIH as being of prime importance. A fourth early railway warehouse 9 miles to the west of the Canal at Brecon was linked to the Swansea Canal over the mountain. i.a Bailey's and Brewer's iron warehouses (now known as Auckland House), Gilwern, 1819 & 1820. The warehouses on the canal bank were connected to the Clydach Rail Road (Railway) which was completed in 1794. The Baileys, ironmasters at nearby Nant-y-glo, were given permission to erect a warehouse on the new wharf at Llanelly at a maximum cost of ?120 in August 1819. A second warehouse was built at Gilwern when another ironmaster, George Brewer, of nearby Coalbrook Vale Ironworks also requested warehouse accommodation on Llanelly Wharf on 17 January 1820. New railways built from the rival Monmouthshire Canal to Coalbrook Vale in 1828 made the second warehouse redundant. Both these two-storey stone-built warehouses have survived in use as domestic accommodation. Multiple arches, now blocked, once allowed railways into their interior. An impressive bank of early 19th-century canalside railway-fed limekilns survives alongside. i.b Baileys' iron-warehouse, Govilon. Another pig-iron and iron-castings warehouse was built at the end of a new railway built from the Baileys' Nant-y-glo blast-furnaces to the Brecknock & Abergavenny Canal at Govilon, opened on 6 December 1821. This railway ended against the eastern wall of the canalside warehouse and a second railway of a different gauge, leading to towns and cities to the east, ended against the western wall. The three-storeyed rubble-sandstone warehouse has important cast-iron fittings: a loading-crane anchorage and loading platform. The building has been sympathetically converted to British Waterways canal offices. Another impressive bank of early 19th-century limekilns survives nearby. i.c Hill's iron-warehouse, Llanfoist. [Figure 10] This warehouse was completed in 1820-21 at the end of the ironmaster Anthony Hill's railway to the Brecknock & Abergavenny Canal wharf at Llanfoist. The ground-floor was open and supported on pillars: grooves were cut into the rock over which the warehouse was built, conforming to the 2ft (0.61m) gauge of the railway. The two-storey stone-built structure is built into a hillside and another railway branch probably ran along the terrace at the rear of the upper storey of the structure. There is a central boat loading-door on the upper storey which is supported by large timber beams spanning the stone pillars of the ground-floor. The upper floor of the warehouse has been converted into a house. i.d Castell-du warehouse, Sennybridge. This warehouse of 1834 is sited 9 miles west of the Brecon end of the Brecknock & Abergavenny Canal, at the northern roadside terminus of a railway from the Swansea Canal to the south. A now blocked stone arch gave this horse-drawn line access into the warehouse interior for the storage of valuable goods coming from the canal to the south. This two-storeyed stone-built structure is used as a farmhouse with early railway stables, offices, and limekilns attached to one side.93

ii	Gare Maritime and Tours et Taxis Warehouse, Brussels (Belgium).
Grading: 2. *; 3. ***; 4. *. Total: 5
	This warehouse complex impressively illustrates the later important relationship between ship canals and inland locomotive-railway transport. The canal from Willebroek and the sea was opened in the 16th century, and extended beyond Brussels to Charleroi in 1827-32, with a widening carried out in the early 20th century. Between the Avenue du Port and the Rue Picard is the Gare Maritime built between 1902 and 1910 by the architects C Bosmans and H Van de Veld, and the Tours et Taxis freight company public warehouse built between 1904 and 1907 by E Van Humbeek. This latter includes three huge freight-handling sheds with cast-iron roofs. The complex has continued in use as a railway goods depot.94 There is now a proposal to re-use part of the buildings as a concert-hall. This is one of the 28 industrial archaeological sites recommended by TICCIH as being of outstanding importance.

Figure 10 Hills iron-warehouse, Powys, Wales (UK), 1820-21: one of a series along the Brecknock and Abergavenny Canal that were served by associated horse- drawn railways


 

Q         Limekilns

Many canals carried coal and limestone for the use of the surrounding agricultural community. Lime was an important cargo for mid-18th century canals in Britain. It was the agricultural revolution which had brought about a large demand for lime as a fertilizer. More lime was also needed for use as a mortar to construct the new workers' housing in the Industrial Revolution. Inside, lime was also used as limewash to make the rooms light enough in the north of England for weaving. Limekilns stood alongside the canals, and some horse-drawn railways also brought limestone and coal down to the canal bank so that the lime produced could be distributed via the canal. It would be difficult to identify one set of limekilns as being of particular technological significance. Rather, they are important for being part of the cultural landscape of the canal.

 

R         Passenger carrying

Canals have always been used for transporting passengers. Indeed, many of the earliest canals in China were designed for carrying troops. This military use continued into the 19th century, with Sweden and Britain, at least, having inland "Royal Retreats" with associated barrack complexes accessible via their inland waterway systems.

Civilian passenger traffic generally developed on a more ad hoc basis, with organized services probably starting on the Willebroek Canal, 30km north of Brussels, in 1618. By 1628 there were services between Groningen and Zuidbroek and from Utrecht to Amsterdam, the latter service operating on a new, and specially built, canal. These services, known as the trekvaart, were to spread all over the Low Countries, with timetables introduced which allowed people to travel widely, regularly, and speedily. The system was one of the most important reasons for the economic development of the 17th-century Netherlands in much the same way as British canals were to serve during the Industrial Revolution in 18th and early 19th century Britain.

In Britain and Ireland similar services grew with the canal system. Many canals had important services, but those on the Grand Canal in Ireland and on the Lancaster Canal in north-western England were particularly influential in the early industrial period. In Ireland, along the Grand Canal, the large hotels built for passengers are still standing, while the Packet Houses in Lancaster and Leeds have recently been restored. In the USA the many waterway passenger routes included the spectacular Pennsylvania Main Line (see "Inclined planes"). Passenger services over the vast distances of China, Russia, the USA, and Canada were particularly important in the process of nation-building. The importance of this type of passenger service declined rapidly with the advent of rail travel but remained of significance on the large waterways of the USA, eastern Europe, and India.

Even today there are many regular services, and although most are for pleasure, there are still some commuter passenger services. In Moscow the Northern River Terminal, built in the 1930s, still serves as a terminus for both pleasure and commuter services. There is also an impressive passenger station at Galati (Romania) on the Danube.

S I T E S

i	Grand Canal Passenger Hotels (Ireland), 1800-10.
Grading: 3. ***; 4. **. Total: 5
	The 127km of the Grand Canal mainline were built between 1755 and 1804. Six passenger "passage boats" were operating by 1790, and lighters with both common and state cabins were introduced in 1834. Five hotels in fine classical style with central pediments and features were built in the first decade of the 19th century and three of these remain at Portobello in Dublin, Robertstown and Shannon Harbour.95

ii	Northern River Terminal, Moscow (Russia), 1930s.
Grading: 3. **; 4. **. Total: 4
	In Moscow, the Northern River Terminal, built in the 1930s, still serves as a terminus for both pleasure and commuter services. The Moscow-Volga Canal, completed from the enlargement of earlier canals and navigations, was 128km long and 5.5m deep and is remarkable for both the elaboration and the size of its structures. It was planned to carry 5 million passengers a year and 3.6 million tonnes of goods traffic and to generate electricity at its eleven locks that could take passenger vessels up to 290m long and 30m wide. It is illustrative of the large scale of waterways traffic on the bigger navigations of the world.96

 

S         Rafting Timber

Many waterways were used for rafting and storing timber. On river navigations, weirs were often designed with sections which could be used by rafts. The weirs on the Vltava, in Prague (Czech Republic), are good examples of those which still have slopes built into them. The large rafts could pass down these without being split into smaller sections.

Many early versions of North American river navigations were specifically built for this trade using rafts or primitive vessels that were broken up for their timber on arrival at their downstream terminus.

Two European canals were built specifically for this trade. The Gaujau Daugava Canal, Riga (Latvia), built between 1899 and 1903, includes what is probably the world's longest lock, over 1km in length. Small rafts brought down the Gauja could be collected together and floated through the canal system, which linked several small lakes, for eventual use in factories in Riga or for export from the port (information from Andris Biedrins, Riga). The canal could be used by conventional boats, unlike the Schwarzenberger Schwemmkanal, crossing the Austrian-Czech border near Aigen (Austria), which was purely for rafting timber. The logs were floated down the canal individually, with "locks" controlling the flow of water; there is even a tunnel. The first section opened in 1793 and the canal was last used in 1961.⁹⁷

 

T         Canal-trade complexes

Canal ports evolved at strategic points on every canal and waterway as trade developed. There were docks for boat building, stabling, workers' housing, and a range of other functions.

i	Worsley canal complex, Bridgewater Canal, Manchester (UK).
Grading: 1. *; 3. **; 4. **. Total: 5
	Adjacent to the conserved twin entrances to the Worsley canal mines are two original masonry overbridges. Between these is the packet house and restored steps from which the early passenger service on the canal was run. Nearby are a crane, an early dry-dock, and a large granary and warehouse; the latter two have been converted into apartments. There are the remains of a limekiln and two large ranges of housing for the workers who toiled at the joint canal and colliery yard alongside the canal. The Earl of Ellesmere's castellated boathouse still stands, from which his passenger barge emerged to convey Queen Victoria along the canal. The surroundings of this complex were later formed into a garden village. The complex is important for being at one of the centres of the Industrial Revolution.

ii	Lauenburg (Germany).
Grading: 1. *; 3. **; 4. *. Total: 4
	In Germany there are still many canal communities as, unlike those in Holland and Belgium, it is traditional for boatmen to have their own house. Many of these communities had boatmen's associations or societies, some dating back to the 13th century. Lauenburg, on the Elbe and at one end of the pioneering Stecknitz Canal (see "Locks" and "Summit level canals"), is one of the oldest such communities. The old town, close to the river, has many houses dating back to the 17th century. The town still has a boating community and there is also a large shipbuilding yard.98

74      N Smith, op.cit., 1.
75      Ibid., 207.
76      Ibid., 160-61.
77      D Newell, The Rideau Canal, in D Newell and R Greenhill, op.cit., 19-45.
78      J Needham, op.cit., 362.
79      Ibid.
80      W J Sivewright, op.cit, 113-14.
81      J H Andrew, The Canal at Smethwick - under, over and finally through the high ground, Industrial Archaeology Review, 17.2, Spring 1995, 171-92.
82      P Beaver, A History of Tunnels, 26: London, 1972.
83      Ibid., 31.
84      L T C Rolt, op.cit., 138.
85      Ibid., 33, and C Hadfield, op.cit., 1976, Site 32.
86      P W Dodds and R W Jones, Dudley Tunnel, 3rd ed, 1-4: Dudley, 1977.
87      The Upper James Atlas (unfinished division): Historic River Sites in the Blue Ridge and Beyond', advance copy of the Atlas prepared for the 1995 Annual Meeting of the Virginia Canals & Navigations Society.
88      R Hohmann, Moselle, River, in B Trinder, op.cit., 478.
89      R S Fitzgerald, Liverpool Road Station, Manchester: Manchester, 1980.
90      D Brumhead & T Wyke, A Walk Round Castlefield, 19-20: Manchester, 1979.
91      Ibid., 17-8.
92      R S Fitzgerald, op.cit., 32.
93      S R Hughes, The Archaeology of an Early Railway System: The Brecon Forest Tramroads, 311-40: Aberystwyth, 1990.
94      B Trinder (ed.), op.cit., 112.
95      Ibid., 306-07.
96      C Hadfield, op.cit., 1986, 180.
97      W Kogler, Der Schwarzenbergsche Schwemmkanal: Vienna, 1993.
98      Correspondence from W Hinsch, Verein zur Förderung des Lauenburger Elbeschiffahrtsmuseum, CV.