121-588: The Tavistock Canal is a canal in the county of Devon in England . It was constructed early in the 19th century to link the town of Tavistock to Morwellham Quay on the River Tamar , where cargo could be loaded into ships. The canal is still in use to supply water to a hydro-electric power plant at Morwellham Quay, and forms part of the Cornwall and West Devon Mining Landscape World Heritage Site . It
242-732: A UNESCO World Heritage Site as part of the Cornwall and West Devon Mining Landscape . In November 2013, South West Water was fined £50,000 after it admitted permitting the discharge of sewage from its Camels Head treatment plant into a tributary of the River Tamar for eight years. Together, the Tamar, Tavy and Lynher form the Tamar Valley National Landscape, a designated Area of Outstanding Natural Beauty . The Tamar Valley Area of Outstanding Natural Beauty covers around 195 km (75 sq mi) around
363-547: A caisson of water in which boats float while being moved between two levels; and inclined planes where a caisson is hauled up a steep railway. To cross a stream, road or valley (where the delay caused by a flight of locks at either side would be unacceptable) the valley can be spanned by a navigable aqueduct – a famous example in Wales is the Pontcysyllte Aqueduct (now a UNESCO World Heritage Site ) across
484-510: A drainage divide atop a ridge , generally requiring an external water source above the highest elevation . The best-known example of such a canal is the Panama Canal . Many canals have been built at elevations, above valleys and other waterways. Canals with sources of water at a higher level can deliver water to a destination such as a city where water is needed. The Roman Empire 's aqueducts were such water supply canals. The term
605-415: A "cistern", or depressed area just downstream from the fall, to "cushion" the water by providing a deep pool for its kinetic energy to be diffused in. Vertical falls work for drops of up to 1.5 m in height, and for discharge of up to 15 cubic meters per second. The transport capacity of pack animals and carts is limited. A mule can carry an eighth-ton [250 pounds (113 kg)] maximum load over
726-470: A Roman settlement named Tamaris, but it is unclear to which of those towns along the Tamar this refers. Plymouth , Launceston and the Roman fort at Calstock have been variously suggested. The river (and/or land on its banks) is designated as a Site of Special Scientific Interest (SSSI), a European Special Area of Conservation, and an Area of Outstanding Natural Beauty. A part of it is also designated as
847-498: A canal from there. The project however advanced no further than Gunnislake , with work ceasing in 1808. Barges of up to 30 tons could then proceed as far as Gunnislake New Bridge, bypassing the weir (above Weir Head) via a 500-yard canal to the west of the river. As the only completed work of the original project, this short canal became known as the Tamar Manure (Navigation) Canal. It had one lock allowing vessels to rise from
968-496: A canal has a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as slack water levels , often just called levels . A canal can be called a navigation canal when it parallels a natural river and shares part of the latter's discharges and drainage basin , and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its valley . A canal can cut across
1089-413: A combination of the three, depending on available water and available path: Smaller transportation canals can carry barges or narrowboats , while ship canals allow seagoing ships to travel to an inland port (e.g., Manchester Ship Canal ), or from one sea or ocean to another (e.g., Caledonian Canal , Panama Canal ). At their simplest, canals consist of a trench filled with water. Depending on
1210-458: A ditch. From here a pipe carries the water under the highway and the infant river Tamar is on its way to the sea at Plymouth." The Upper Tamar Lake and Lower Tamar Lake are two small reservoirs on the Tamar's upper course. The Lower Lake was constructed in the 1820s to feed the Bude Canal ; it is now a nature reserve. The Upper Lake was constructed in the 1970s and supplies fresh water to
1331-475: A flow of water along the canal, which aided the passage of boats towards the quay, and also helped to power waterwheels along the route. Between 1817 and 1819, a 2-mile (3.2 km) extension was constructed to slate quarries and a general wharf at Mill Hill . This cost £8,000, and because there was a lack of water to supply locks, the difference in level was accommodated by building a counterbalanced, double track inclined plane. Boats were loaded onto cradles, and
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#17327718284351452-549: A journey measured in days and weeks, though much more for shorter distances and periods with appropriate rest. Besides, carts need roads. Transport over water is much more efficient and cost-effective for large cargoes. The oldest known canals were irrigation canals, built in Mesopotamia c. 4000 BC , in what is now Iraq . The Indus Valley civilization of ancient India ( c. 3000 BC ) had sophisticated irrigation and storage systems developed, including
1573-463: A line running at the centre of the river — where the river is tidal, it is the centre of the low water channel. This "centre of river" arrangement ends just upstream of the Tamar Bridge at Saltash , downstream of which the counties officially extend only to their respective (tidal) bank's low water mark. The river is dammed at two points of its upper course, forming two reservoirs in place of
1694-614: A rail connection from Plymouth to London was opened, and fresh produce could be landed at the Devonport steamer quays in the evening and be on sale in London by the next morning. The growing city population created a large demand for sightseeing cruises on the river; this was a significant source of traffic from 1823, with the launch of the Cornish steam packet Sir Francis Drake , until the outbreak of World War II . Mineral traffic on
1815-581: A rather low gradient for its time. The canal is still in use after renovation. In the Middle Ages , water transport was several times cheaper and faster than transport overland. Overland transport by animal drawn conveyances was used around settled areas, but unimproved roads required pack animal trains, usually of mules to carry any degree of mass, and while a mule could carry an eighth ton, it also needed teamsters to tend it and one man could only tend perhaps five mules, meaning overland bulk transport
1936-570: A spell on Tamara, turning her into a bubbling spring, which produced the Tamar river and flowed all the way to the sea. Tawradge awoke to find his beloved had become a river; in despair, he sought the advice of a magician, who turned him into a river (the River Torridge and the River Taw ) so that he could hope to reunite with Tamara. Tawradge was never able to find and merge with his beloved Tamara, instead turning north toward Bideford and
2057-459: A uniform altitude. Other, generally later, canals took more direct routes requiring the use of various methods to deal with the change in level. Canals have various features to tackle the problem of water supply. In cases, like the Suez Canal, the canal is open to the sea. Where the canal is not at sea level, a number of approaches have been adopted. Taking water from existing rivers or springs
2178-558: A waste product but later offering an important source of revenue as copper and tin extraction declined in profitability. The refined product was exported worldwide, in particular to the southern United States, where it was used as an insecticide in the cotton fields. In the 13th century lead and silver output from the royal mines on the Bere peninsula (between the Tamar and the Tavy ) was significant, and production continued intermittently until
2299-464: A water supply. The power plant and canal now belong to South West Water , and still feed power to the National Grid . A programme of archaeological and historical research was carried out around Morwellham Quay between 2002 and 2010. Excavations in 2006–2007 uncovered the tunnel on the second inclined plane, part of which is now being restored. Morwellham Quay is now an open-air museum. Part of
2420-506: Is a river in south west England that forms most of the border between Devon (to the east) and Cornwall (to the west). A large part of the valley of the Tamar is protected as the Tamar Valley National Landscape (an Area of Outstanding Natural Beauty ), and some is included in the Cornwall and West Devon Mining Landscape (a World Heritage Site ) due to its historic mining activities. The Tamar's source
2541-608: Is a weir just downstream of the village of Gunnislake . Waterborne traffic through the Hamoaze is controlled by the Queen's Harbour Master for Plymouth, who is responsible for managing navigation along the entire tidal Tamar. The Royal Navy has one of its three main naval bases at Devonport , situated on the Hamoaze, upstream of which the river is now used largely by recreational craft. Excursions operate (April to October only) on
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#17327718284352662-422: Is a channel that cuts across a drainage divide , making a navigable channel connecting two different drainage basins . Both navigations and canals use engineered structures to improve navigation: Since they cut across drainage divides, canals are more difficult to construct and often need additional improvements, like viaducts and aqueducts to bridge waters over streams and roads, and ways to keep water in
2783-474: Is another notable structure on the Tamar, being 120 feet (37 m) high with twelve 60-foot (18 m) wide arches, of which three of the piers stand in the river, and was built between 1904 and 1907. The total length of the tidal river (which, like other tidal waters in England, has public right of navigation) is 19.2 miles (30.9 km). The normal tidal limit (noted on Ordnance Survey maps as 'NTL')
2904-468: Is at Horsebridge (1437), and the next oldest is Greystone Bridge near Lawhitton — this arched stone bridge was built in 1439. Gunnislake New Bridge was built in 1520 by Sir Piers Edgcumbe, the owner of Cotehele and Mount Edgcumbe. The Gunnislake bridge was a main route into south east Cornwall and the lowest bridge over the Tamar until the Tamar Bridge at Saltash was opened in 1962. The lower Tamar
3025-479: Is less than 6 km (3.7 mi) from the north Cornish coast, but it flows southward across the peninsula to the south coast. The total length of the river is 61 miles (98 km). At its mouth, the Tamar flows into the Hamoaze before entering Plymouth Sound , a bay in the English Channel . Tributaries of the river include the rivers Inny , Ottery , Kensey and Lynher (or St Germans River ) on
3146-490: Is on display at Morwellham Quay Museum and recent archaeological survey work has found more wrought iron plates within the canal tunnel. A report from 1888 describes the boats as 30 feet (9.1 m) in length, 5 feet (1.5 m) in width, and made of rivetted iron, while an earlier description from 1826 gives the dimensions as 4 feet 6 inches (1.37 m) wide by 2 feet 6 inches (0.76 m) deep. These iron barges were first referred to in 1811, when one
3267-701: Is presumed, introduced in Italy by Bertola da Novate in the 16th century. This allowed wider gates and also removed the height restriction of guillotine locks . To break out of the limitations caused by river valleys, the first summit level canals were developed with the Grand Canal of China in 581–617 AD whilst in Europe the first, also using single locks, was the Stecknitz Canal in Germany in 1398. In
3388-599: Is rarely less than 30 metres (98 ft) wide. In the 5th century BC, Achaemenid king Xerxes I of Persia ordered the construction of the Xerxes Canal through the base of Mount Athos peninsula, Chalkidiki , northern Greece. It was constructed as part of his preparations for the Second Persian invasion of Greece , a part of the Greco-Persian Wars . It is one of the few monuments left by
3509-629: Is spanned also by the Royal Albert Bridge (built 1859), a rail bridge now adjacent to the newer Tamar Bridge. Both of these bridges are between Saltash (known as the 'Gateway to Cornwall') and Plymouth. Further downstream, crossing the Hamoaze , is the Torpoint Ferry — a chain ferry connecting Torpoint to Devonport — and at the most downstream part of the Hamoaze there is also the Cremyll Ferry . The Calstock Viaduct
3630-418: Is steeper than the desired canal gradient. They are constructed so the falling water's kinetic energy is dissipated in order to prevent it from scouring the bed and sides of the canal. A canal fall is constructed by cut and fill . It may be combined with a regulator, bridge, or other structure to save costs. There are various types of canal falls, based on their shape. One type is the ogee fall, where
3751-452: Is the pound lock , which consists of a chamber within which the water level can be raised or lowered connecting either two pieces of canal at a different level or the canal with a river or the sea. When there is a hill to be climbed, flights of many locks in short succession may be used. Prior to the development of the pound lock in 984 AD in China by Chhaio Wei-Yo and later in Europe in
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3872-727: Is the final place to turn boats; it was from here that smaller craft could begin their journey on the Tamar Manure Canal . In 1794 the Tamar Manure Navigation Company was formed to extend navigation inland for a further 30 miles, to Tamerton Bridge in North Tamerton . An Act of Parliament of 1796 authorised the works, with the company empowered to improve and manage navigation on the Tamar from Morwellham Quay upstream to Boat Pool, at Blanchdown (just upstream of Gunnislake), and to construct
3993-408: Is unusual for a canal, as it has a gentle slope over its length, resulting in a considerable flow of water. Morwellham Quay is on the River Tamar , and although it is about 23 miles (37 km) from the sea, the river is still tidal there. The quay was the furthest point inland to which the river was navigable, and it had served Tavistock as a port since the 12th century. Ships of 200 tons were using
4114-461: The Baltic , in large baulks for use as pit props in the mines, and coal from Wales to supply the mine pumping engines. Tavistock was one of the three stannary towns of Devon, and large quantities of refined tin ore were exported through Morwellham from the 12th century until 1838, when the requirement to pay duty on the metal at one of the specified towns was relaxed. The opening in 1817 of
4235-597: The Bristol Channel and is still said to mourn his love, the Tamar. This legend explains why the River Torridge, which rises only 500 metres from the Tamar, veers away from the Tamar and forms a huge arc, eventually flowing to the North Devon coast. The other giant, Tavy, also awoke in despair and sought the aid of his own father, also a powerful magician. His father turned Tavy into a river as well, and
4356-512: The Bude area, as well as having some recreational use. The east bank of the Tamar was fixed as the border of Cornwall by King Athelstan in the year 936. Several villages north of Launceston , to the west of the Tamar, were transferred to Devon at some point in the eleventh century when the border was changed to follow the River Ottery westward, rather than the Tamar. The county boundary
4477-658: The Elbe , Oder and Weser being linked by canals. In post-Roman Britain, the first early modern period canal built appears to have been the Exeter Canal , which was surveyed in 1563, and open in 1566. The oldest canal in the European settlements of North America, technically a mill race built for industrial purposes, is Mother Brook between the Boston, Massachusetts neighbourhoods of Dedham and Hyde Park connecting
4598-543: The Naviglio Grande built between 1127 and 1257 to connect Milan with the river Ticino . The Naviglio Grande is the most important of the lombard " navigli " and the oldest functioning canal in Europe. Later, canals were built in the Netherlands and Flanders to drain the polders and assist transportation of goods and people. Canal building was revived in this age because of commercial expansion from
4719-545: The Phoenix metropolitan area was the most complex in ancient North America. A portion of the ancient canals has been renovated for the Salt River Project and now helps to supply the city's water. The Sinhalese constructed the 87 km (54 mi) Yodha Ela in 459 A.D. as a part of their extensive irrigation network which functioned in a way of a moving reservoir due to its single banking aspect to manage
4840-528: The River Brue at Northover with Glastonbury Abbey , a distance of about 1.75 kilometres (1,900 yd). Its initial purpose is believed to be the transport of building stone for the abbey, but later it was used for delivering produce, including grain, wine and fish, from the abbey's outlying properties. It remained in use until at least the 14th century, but possibly as late as the mid-16th century. More lasting and of more economic impact were canals like
4961-691: The River Severn by John Wilkinson of Broseley Ironworks, Shropshire, is now thought to have been of cast iron plates, bolted together. The main line of the canal starts at the Abbey Weir in Tavistock , where water is taken from the River Tavy . Passing through wharfs in Tavistock, it proceeds towards Morwellham Quay in a fairly straight line, with a large horseshoe loop when it meets
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5082-614: The Songhai Empire of West Africa, several canals were constructed under Sunni Ali and Askia Muhammad I between Kabara and Timbuktu in the 15th century. These were used primarily for irrigation and transport. Sunni Ali also attempted to construct a canal from the Niger River to Walata to facilitate conquest of the city but his progress was halted when he went to war with the Mossi Kingdoms . Around 1500–1800
5203-616: The Tavistock Canal , between Tavistock and Morwellham, facilitated traffic. Later, the East Cornwall Mineral Railway provided an outlet through the quays of Calstock from the Cornish side of the valley. Other significant cargoes exported were quarried granite, and later, copper, lead and manganese ores, with their important by-product of arsenic . Arsenic was extracted from mispickel , once regarded as
5324-413: The estuary narrows into the tidal river, some 8.4 miles (13.5 km) upstream from Plymouth Sound. Vessels of 300 tons sailed as far inland as Morwellham, 17.2 miles (27.7 km) along the river from the sea. A further stretch of 1.8 miles (2.9 km) upstream to Weir Head, near Gunnislake, is accessible to smaller boats. Weir Head is just downstream of the weir at Gunnislake (the tidal limit) and
5445-556: The reservoirs built at Girnar in 3000 BC. This is the first time that such planned civil project had taken place in the ancient world. In Egypt , canals date back at least to the time of Pepi I Meryre (reigned 2332–2283 BC), who ordered a canal built to bypass the cataract on the Nile near Aswan . In ancient China , large canals for river transport were established as far back as the Spring and Autumn period (8th–5th centuries BC),
5566-675: The stannary town of Tavistock was added to the World Heritage List during the 30th Session of the UNESCO World Heritage Committee in Vilnius, July 2006. The Environment Agency measures the water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at
5687-404: The stratum the canal passes through, it may be necessary to line the cut with some form of watertight material such as clay or concrete. When this is done with clay, it is known as puddling . Canals need to be level, and while small irregularities in the lie of the land can be dealt with through cuttings and embankments, for larger deviations other approaches have been adopted. The most common
5808-411: The " Three Towns " (Plymouth, Devonport and Stonehouse ) at the mouth of the river offered an important market for the valley's agricultural produce, needed in particular to serve the victualling requirements of the royal dockyard , and this was always carried by boat. In 1820 or 1821 the first paddle steamer on the Tamar inaugurated a service between Calstock and Devonport to deliver foodstuffs. In 1859
5929-471: The 12th century. River navigations were improved progressively by the use of single, or flash locks . Taking boats through these used large amounts of water leading to conflicts with watermill owners and to correct this, the pound or chamber lock first appeared, in the 10th century in China and in Europe in 1373 in Vreeswijk , Netherlands. Another important development was the mitre gate , which was, it
6050-472: The 15th century, either flash locks consisting of a single gate were used or ramps, sometimes equipped with rollers, were used to change the level. Flash locks were only practical where there was plenty of water available. Locks use a lot of water, so builders have adopted other approaches for situations where little water is available. These include boat lifts , such as the Falkirk Wheel , which use
6171-427: The 19th century. The Johnson Matthey smelting works at Weir Quay extracted silver and lead not only from local ore, but also from ore imported by sea from Europe and from as far away as Newfoundland . Fluorspar from the lead mine tailings was exported to France for use in the manufacture of glassware. The old ferry crossings developed into the busy river quays of the 18th and 19th centuries. The development of
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#17327718284356292-626: The Cornish side and the Deer and Tavy on the Devon side. The name Tamar (or Tamare) was mentioned by Ptolemy in the 2nd century AD in his Geography . The name is said to mean "great water". The Tamar is one of several British rivers whose ancient name is assumed by some to be derived from a prehistoric river word apparently meaning "dark flowing" and which it shares with the River Thames . The seventh-century Ravenna Cosmography mentions
6413-597: The Mill Hill Branch of the canal still survives, from the junction near the Lumburn aqueduct to the A390 Tavistock to Liskeard road. The bed can be seen along this length, although it is dry. The next section is marked by the tramroad that ran to Millhill crossroads, but the canal bed is not obvious. Beyond the road, there is no evidence of the inclined plane, nor of the route from the top of the incline to
6534-669: The Millhill slate quarries would be served by a branch from the main line. It would carry copper ore, from both the Wheal Friendship and the Wheal Crowndale mine which had recently opened nearer to Tavistock. Other cargo would include slate, limestone and general goods. The canal would be suitable for tub boats , and would be built entirely on land owned by the Duke of Bedford, who approved of the project. The estimated cost
6655-590: The Persian Empire in Europe . Greek engineers were also among the first to use canal locks , by which they regulated the water flow in the Ancient Suez Canal as early as the 3rd century BC. There was little experience moving bulk loads by carts, while a pack-horse would [i.e. 'could'] carry only an eighth of a ton. On a soft road a horse might be able to draw 5/8ths of a ton. But if
6776-785: The Southwest by 1300 CE. Archaeologists working at a major archaeological dig in the 1990s in the Tucson Basin, along the Santa Cruz River, identified a culture and people that may have been the ancestors of the Hohokam. This prehistoric group occupied southern Arizona as early as 2000 BCE, and in the Early Agricultural period grew corn, lived year-round in sedentary villages, and developed sophisticated irrigation canals. The large-scale Hohokam irrigation network in
6897-671: The Tamar Estuary Nature Reserve, owned by the Cornwall Wildlife Trust . The site was designated in 1991 for its biodiversity and varying habitats that support a large number of wader and wildfowl species, as well as the special interest of its marine biology. The site supports a nationally important wintering population of avocet and supports species such as black-tailed godwit , Eurasian whimbrel , greenshank , spotted redshank , green sandpiper and golden plover . Throughout human history
7018-414: The Tamar are very unusual and support species such as the hydroid Cordylophora caspia . The Tamar is one of a few estuaries where zonation of rocky habitats (intertidal and subtidal) can be observed along an estuarine gradient. The Tamar–Tavy Estuary is a Site of Special Scientific Interest (SSSI) covering the tidal estuaries of the River Tamar and the River Tavy . Part of the Tamar estuary also forms
7139-484: The Tamar crossings. In medieval times the transport of goods to supply the Benedictine abbey at Tavistock , four miles by track from the river port of Morwellham, was significant. Sea sand from the coast was imported to spread on farmland, until in the 18th century a dressing of lime was found to be more beneficial. Large quantities of limestone and coal were then imported to burn in the numerous limekilns on
7260-463: The Tamar was an important river for shipping copper from ports such as Morwellham Quay , Calstock and New Quay (Devon) to south Wales where it would be smelted. The valley forms district A10i of the Cornwall and West Devon Mining Landscape . The river has long been famous for the quality of its salmon whilst the valley was known nationally for the high quality, and early, soft fruit and market gardens sheltered by its steeply winding slopes. There
7381-484: The Tavy river as far as Lydford , and burned Ordwulf 's monastery at Tavistock . During the English Civil War , Cornwall was entirely loyal to King Charles I and the Royalist cause. However, Devon was primarily Parliamentarian ; thus the River Tamar became the site of many battles, such as the Battle of Gunnislake New Bridge on 20 July 1664. Each side of the Tamar understood that if they were either to invade or to defend themselves, they had to have control of
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#17327718284357502-453: The banks of the river. A traditional Cornish tale claims that the devil would never dare to cross the River Tamar into Cornwall for fear of ending up as a pasty filling. Though unusual landscape features are often named after the devil (e.g. devil's frying pan) it used to be said that the devil never came to Cornwall: he once reached Torpoint and immediately noticed that various kinds of pie were customary; he feared that devilly pie might be
7623-422: The border follows the river (from source to sea) currently exist, all of which are upstream of the confluence of the River Deer , in the upper course of the Tamar. Part of the Cornish civil parish of North Tamerton extends east across the river, whilst parts of the Devon civil parishes of Bridgerule and Pancrasweek extend west across the Tamar. Where the border does follow the Tamar, it is defined as being along
7744-415: The canal closed to navigation it continued to be used to supply water to various industrial activities at Morwellham Quay . The last of these was to operate a tin and wolfram mill at the Bedford United Mine , a supply which ceased in 1930. In 1933 the canal was purchased by the West Devon Electric Supply Co. Ltd, who constructed a hydro-electric power plant at Morwellham Quay using the canal and tunnel as
7865-436: The canal pressure with the influx of water. It was also designed as an elongated reservoir passing through traps creating 66 mini catchments as it flows from Kala Wewa to Thissa Wawa . The canal was not designed for the quick conveying of water from Kala Wewa to Thissa Wawa but to create a mass of water between the two reservoirs, which would in turn provided for agriculture and the use of humans and animals. They also achieved
7986-418: The canal to form a dam. They are generally placed in pre-existing grooves in the canal bank. On more modern canals, "guard locks" or gates were sometimes placed to allow a section of the canal to be quickly closed off, either for maintenance, or to prevent a major loss of water due to a canal breach. A canal fall , or canal drop, is a vertical drop in the canal bed. These are built when the natural ground slope
8107-462: The canal. Where large amounts of goods are loaded or unloaded such as at the end of a canal, a canal basin may be built. This would normally be a section of water wider than the general canal. In some cases, the canal basins contain wharfs and cranes to assist with movement of goods. When a section of the canal needs to be sealed off so it can be drained for maintenance stop planks are frequently used. These consist of planks of wood placed across
8228-418: The canal. However, in 1857–58 the mining company built a tramway from the mine to the quay. It arrived above the quay on the 400-foot (120 m) contour, and a second inclined plane was constructed, which ran through a tunnel beneath the village green. In 1859, the railways arrived at Tavistock, in the form of the South Devon and Tavistock Railway . In order to remain competitive, £300 was spent on renewing
8349-409: The channel. There are two broad types of canal: Historically, canals were of immense importance to commerce and the development, growth and vitality of a civilization. In 1855 the Lehigh Canal carried over 1.2 million tons of anthracite coal; by the 1930s the company which built and operated it for over a century ceased operation. The few canals still in operation in our modern age are a fraction of
8470-401: The construction of the canal. The land was donated by the Duke, who took 125 of the 1,000 shares. Taylor, who also managed Wheal Friendship mine, acted as engineer, and work started in August 1803. The largest engineering feature of the canal was a tunnel under Morwell Down. When cutting of it began, copper ore was discovered close to the Tavistock end, and this became the Wheal Crebor mine, which
8591-399: The drop follows an s-shaped curve to create a smooth transition and reduce turbulence . However, this smooth transition does not dissipate the water's kinetic energy, which leads to heavy scouring. As a result, the canal needs to be reinforced with concrete or masonry to protect it from eroding. Another type of canal fall is the vertical fall, which is "simple and economical". These feature
8712-452: The equipment on the inclined plane, and thought was given to buying a tug. However, Mr T. Knight proposed a system of ropes powered by waterwheels to pull the boats through the tunnel, and the machinery was installed. After less than a year it was acknowledged that the system was a failure, but the committee failed to find a way to dispose of the rope, although they tried for many years. Traffic and profits continued to fall, despite reductions in
8833-476: The export of bricks and granite along this short navigation proved profitable for many years. The navigation from Launceston to Tamerton was completed in 1826 as part of a separate project, the Bude Canal . The Tamar Manure Navigation ceased functioning in 1929 and the company was wound up in 1942. In 997 according to the Anglo-Saxon Chronicle , raiding Vikings travelled up the Tamar and then
8954-670: The first summit level canal to use pound locks in Europe was the Briare Canal connecting the Loire and Seine (1642), followed by the more ambitious Canal du Midi (1683) connecting the Atlantic to the Mediterranean. This included a staircase of 8 locks at Béziers , a 157 metres (515 ft) tunnel, and three major aqueducts. Canal building progressed steadily in Germany in the 17th and 18th centuries with three great rivers,
9075-485: The foresight and determination of John Taylor. Driving a tunnel of such length through solid and often hard rock required new drainage techniques, and finishing it off with "the greatest inclined plane in Southern England" required great boldness. It carried slate, silver-lead ore and copper ore from the Tavistock area to the quay, and general goods including limestone, coal, iron and timber for Tavistock in
9196-462: The freedom to make deliveries well away from rail lined road beds or ditches in the dirt which could not operate in the winter. The longest extant canal today, the Grand Canal in northern China, still remains in heavy use, especially the portion south of the Yellow River . It stretches from Beijing to Hangzhou at 1,794 kilometres (1,115 miles). Canals are built in one of three ways, or
9317-451: The giants on a dance, but never let them touch her, instead darting out of reach whenever they came too close. Tamara's father, who had been out looking for her, located her just as the giants finally caught up with her near Morwenstow . He flew into a rage and used a spell to put Tavy and Tawradge into a deep sleep. This infuriated Tamara, who subsequently refused to return to the underworld with her father. He became even more enraged and cast
9438-624: The heat of the Earth's core, which gave rise to ores containing tin , copper , tungsten , lead and other minerals in the Valley. The medieval estate of Cotehele , owned by the Edgcumbe family, was a significant producer of silver for the Royal Mint . During the industrial revolution, there was significant mining activity near the river, between Gunnislake and Weir Quay. During this period,
9559-708: The higher waters of the Charles River and the mouth of the Neponset River and the sea. It was constructed in 1639 to provide water power for mills. In Russia, the Volga–Baltic Waterway , a nationwide canal system connecting the Baltic Sea and Caspian Sea via the Neva and Volga rivers, was opened in 1718. River Tamar The Tamar ( / ˈ t eɪ m ɑːr / ; Cornish : Dowr Tamar )
9680-489: The level by 237 feet (72 m) to the quay at Morwellham. There were two tracks, one running to the quay, and a second which ended some 30 feet (9.1 m) higher at ore-chutes above the Lower Copper Quay. The rails were initially L-shaped cast-iron plate rails, spaced 46 inches (1,200 mm) apart between the flanges, although trough-shaped rails were used in places on the quay, particularly where roads crossed
9801-549: The load were carried by a barge on a waterway, then up to 30 tons could be drawn by the same horse. — technology historian Ronald W. Clark referring to transport realities before the industrial revolution and the Canal age . Hohokam was a society in the North American Southwest in what is now part of Arizona , United States, and Sonora , Mexico. Their irrigation systems supported the largest population in
9922-505: The loaded boats passing down the incline raised the unladen ones, with three horses assisting if necessary. The incline was relatively shallow, as it was 936 feet (285 m) long and only rose by 19.5 feet (5.9 m) over this length. The rails were of "L" section, made of cast iron, and spaced 70.5 inches (1.79 m) between the flanges. The cradle was about 20 feet (6.1 m) long and ran on 24-inch (0.61 m) cast iron wheels. The branch appears to have closed around 1831, but in 1844,
10043-480: The longest canal in the world today and the oldest extant one. It is 1,794 kilometres (1,115 mi) long and was built to carry the Emperor Yang Guang between Zhuodu ( Beijing ) and Yuhang ( Hangzhou ). The project began in 605 and was completed in 609, although much of the work combined older canals, the oldest section of the canal existing since at least 486 BC. Even in its narrowest urban sections it
10164-534: The longest one of that period being the Hong Gou (Canal of the Wild Geese), which according to the ancient historian Sima Qian connected the old states of Song, Zhang, Chen, Cai, Cao, and Wei. The Caoyun System of canals was essential for imperial taxation, which was largely assessed in kind and involved enormous shipments of rice and other grains. By far the longest canal was the Grand Canal of China , still
10285-573: The lower Tamar (below Launceston ) and its tributaries the Tavy and the Lynher . It was first proposed in 1963, but was not designated until 1995. The highest point in the AONB is Kit Hill , 334 metres above sea level. The Tamar Discovery Trail is a 35-mile hiking route following the course of the Tamar through the valley. The Plymouth Sound and Estuaries are a Special Area of Conservation . Rocky reefs in low salinity estuarine conditions far inland on
10406-547: The natural river: at Upper Tamar Lake the border follows the line of the river as it was prior to the construction of the reservoir (therefore now within the lake), whilst at the older Lower Tamar Lake the border was re-aligned along a (now disused) re-routing of the river to the reservoir's west side, placing the lake in Devon. List of crossings of the River Tamar The river has 22 road crossings, including some medieval stone bridges. The oldest bridge still extant
10527-554: The next kind so returned to Devon. This legend is set to music in the traditional Cornish folk song Fish and Tin and Copper . The legend behind the name involves a nymph by the name of Tamara, who lived in the underworld. Tamara wanted to wander freely in the mortal world, against the advice of her parents. One day, wandering in Dartmoor , she happened to meet two giants called Tavy and Torridge (or Tawradge). Both giants became smitten with Tamara and vied for her affections. Tamara led
10648-506: The numbers that once fueled and enabled economic growth, indeed were practically a prerequisite to further urbanization and industrialization. For the movement of bulk raw materials such as coal and ores are difficult and marginally affordable without water transport. Such raw materials fueled the industrial developments and new metallurgy resulting of the spiral of increasing mechanization during 17th–20th century, leading to new research disciplines, new industries and economies of scale, raising
10769-481: The outside world only through the port of Calstock, was extended to the Plymouth, Devonport and South Western Junction Railway at Bere Alston . Tourist and market traffic on the river, using purpose-built or converted steamers, remained substantial until the Devonport piers were closed and the ships requisitioned on the outbreak of war in 1939. Rocks around the edge of Dartmoor were mineralised by fluids driven by
10890-471: The owners of a new slate quarry at Mill Hill requested that the company re-open the canal or replace it with a tramway . The canal above the Gunnislake to Tavistock road crossing was relaid as a tramway at a cost of £1,381, but the quarry was not a success, and only shipped slates between 1848 and 1850. Despite its modest length, the canal's design and execution was a remarkable achievement, owing much to
11011-400: The parish of Bridgerule to Devon and part of the parish of North Tamerton to Cornwall — these latter transfers created two of the present-day 'exceptions' to the river boundary. The modern administrative border between Devon and Cornwall more closely follows the Tamar and Hamoaze than the 'historic' county border (of the 11th to 19th centuries). Only three 'exceptions' to the rule that
11132-604: The pre-railroad days of the industrial revolution, water transport was the gold standard of fast transportation. The first artificial canal in Western Europe was the Fossa Carolina built at the end of the 8th century under personal supervision of Charlemagne . In Britain, the Glastonbury Canal is believed to be the first post-Roman canal and was built in the middle of the 10th century to link
11253-483: The quantity and varieties of invertebrates , angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail. According to Ordnance Survey mapping, the source of the Tamar is at Woolley Moor, approximately 3.5 miles (5.6 km) from the north Cornish coast, at 50°55′06″N 4°27′48″W / 50.9184°N 4.4633°W / 50.9184; -4.4633 . The location of
11374-406: The quarry. Download coordinates as: Canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation ) or for conveyancing water transport vehicles (e.g. water taxi ). They carry free, calm surface flow under atmospheric pressure , and can be thought of as artificial rivers . In most cases,
11495-510: The quay by 1800, and there was a growing trade in copper, which was being mined locally, particularly since the Wheal Friendship mine had opened around 1797. In 1802, John Taylor , a local civil engineer with interests in the mining of metal ores, surveyed the route for a canal to run from Tavistock to Morwellham, and it was discussed at a meeting in March 1803 in Tavistock. The canal would be 16 feet (4.9 m) wide and 3 feet (0.9 m) deep, and
11616-474: The reverse direction. For nearly 40 years it was a profitable concern, carrying over one million tons of cargo during this period. In 1844, the largest lode of copper ore in Europe was discovered just 4 miles (6.4 km) from Morwellham Quay , but the canal was unable to profit from the discovery, as the ore, which was mined by the Devon Great Consols company, lay in a different direction from
11737-516: The river between Plymouth and Calstock ; excursions used to operate as far as Morwellham Quay , but were suspended indefinitely in 2016. A passenger ferry also operates April to October between Cotehele Quay and Calstock. A typical Tamar vessel was a sailing barge , built on the open river bank, of up to 60 tons, with a peaked, gaff-rigged mainsail and a fore staysail . The Tamar was navigable by seagoing ships of up to 400 register tons as far inland as Weir Quay , near Bere Alston , where
11858-490: The river diminished towards the end of the 19th century, after the Plymouth, Devonport and South Western Junction Railway reached Tavistock in 1859 (so making the Tavistock Canal to Morwellham redundant for transport, although it remains in use as a source of hydropower ) and as the copper and tin mines became exhausted. The decline accelerated from 1894, when the East Cornwall Mineral Railway , until then linked to
11979-403: The river quays; the lime had to be made locally as it was not slaked before application, and was too chemically reactive for transport by water after burning. Later, street sweepings and other refuse from Plymouth and Devonport , together with bones for the newly discovered bone fertiliser , were carried inland to manure the fields. Other regular imports were timber from British Columbia and
12100-403: The spring is a "high windswept plateau largely devoid of farmland, and inhabited by stunted trees and wiry undergrowth." The exact source of the river is difficult to pinpoint, because it arises "from a boggy morass . . . behind a hedge near some willow trees at Woolley Barrows . . . A small square stone culvert drains the first tentative trickle of water away from the bog, through a hedge and into
12221-480: The standard of living for any industrialized society. Most ship canals today primarily service bulk cargo and large ship transportation industries, whereas the once critical smaller inland waterways conceived and engineered as boat and barge canals have largely been supplanted and filled in, abandoned and left to deteriorate, or kept in service and staffed by state employees, where dams and locks are maintained for flood control or pleasure boating. Their replacement
12342-591: The tidal Tamar to the water level above the weir. A salmon ladder bypassed the lock. The navigable route along the Tamar and the Manure Canal that was managed by the company (from Morwellham Quay upstream to Blanchdown) was known as the Tamar Manure Navigation and was 3.0 miles (4.8 km) in length. The import of fertilizer (at the time of the construction of the canal all types of which were typically referred to as "manure") and coal and
12463-419: The tolls. The company petitioned the duke in 1866 to reduce tolls for the use of Morwellham Quay, but he did not respond. In 1870, they offered all of the shares to the duke, at a price of £10 each, but again the duke did not show interest. Two years later, the duke made an offer of £8 per share, providing that the company paid half of the cost of an act of Parliament to authorise transfer of ownership to him. This
12584-417: The tracks. Four-wheeled tipping wagons which had larger wheels at the front than at the rear were used on the twin tracks, which operated independently. The system was powered by a large overshot waterwheel, 28 feet (8.5 m) in diameter and 4 feet (1.2 m) wide, situated alongside the winding house at the head of the incline, which was fed with water from the canal. It drove a declutchable winch, to which
12705-625: The valley has been almost continuously exploited for its rich mineral and metal deposits including silver, tin, lead and arsenic leaving a unique archaeological landscape which forms a significant part of the Cornwall and West Devon Mining Landscape. Remains include wheal or engine houses, deep and open cast mines dating from the Bronze Age through to the medieval and modern era, the export docks at Morwellham Quay were once an international centre of trade in copper, lead and arsenic. The valley, with
12826-573: The valley of the River Dee . Another option for dealing with hills is to tunnel through them. An example of this approach is the Harecastle Tunnel on the Trent and Mersey Canal . Tunnels are only practical for smaller canals. Some canals attempted to keep changes in level down to a minimum. These canals known as contour canals would take longer, winding routes, along which the land was
12947-529: The valley of the River Lumburn , which it crosses by a large aqueduct. The two mile Mill Hill branch turned off immediately after the aqueduct. After about 3 miles (4.8 km) the main line reaches the northern portal of the Morwell Down tunnel, which emerges 1.5 miles (2.4 km) later above the quay. A short length of canal after the tunnel brought boats to the top of the inclined plane. After
13068-403: The wagons were attached by chains. Wagons arriving at the top of the incline passed onto a sloping platform, which moved to a horizontal position due to the weight of the wagon, and this disconnected the waterwheel from the drum holding the chain. The rails were later replaced by wrought iron edge rails, and the chains by cables. The main line of the canal was formally opened on 24 June 1817; this
13189-423: The workings drained, and the other to clean the air. Both were powered by water wheels , driven by the canal water. The tunnel, which was driven through elvan rock and killas clay-slate , is 360 feet (110 m) below Morwell Down at its deepest point, and it was finished in 1816. At the tunnel's southern end, the canal was on the 250-foot (76 m) contour, and Taylor constructed an inclined plane to drop
13310-532: Was accepted, and the Tavistock Canal Act 1873 ( 36 & 37 Vict. c. xvi) was obtained in May 1873, after which the duke paid £3,200 to the shareholders. Although he had no responsibility to keep the canal open, it was listed as being open in official returns for 1883, but not in 1898. None of the boats used on the canal has survived completely, but a wrought iron rudder found in the tunnel in 1976
13431-466: Was also expensive, as men expect compensation in the form of wages, room and board. This was because long-haul roads were unpaved, more often than not too narrow for carts, much less wagons, and in poor condition, wending their way through forests, marshy or muddy quagmires as often as unimproved but dry footing. In that era, as today, greater cargoes, especially bulk goods and raw materials , could be transported by ship far more economically than by land; in
13552-458: Was an option in some cases, sometimes supplemented by other methods to deal with seasonal variations in flow. Where such sources were unavailable, reservoirs – either separate from the canal or built into its course – and back pumping were used to provide the required water. In other cases, water pumped from mines was used to feed the canal. In certain cases, extensive "feeder canals" were built to bring water from sources located far from
13673-470: Was gradual, beginning first in the United States in the mid-1850s where canal shipping was first augmented by, then began being replaced by using much faster , less geographically constrained & limited, and generally cheaper to maintain railways . By the early 1880s, canals which had little ability to economically compete with rail transport, were off the map. In the next couple of decades, coal
13794-424: Was increasingly diminished as the heating fuel of choice by oil, and growth of coal shipments leveled off. Later, after World War I when motor-trucks came into their own, the last small U.S. barge canals saw a steady decline in cargo ton-miles alongside many railways, the flexibility and steep slope climbing capability of lorries taking over cargo hauling increasingly as road networks were improved, and which also had
13915-522: Was launched on the canal on Easter Monday. In all, nine were built between then and 1817, when 300 invited guests were carried along the canal in them on the occasion of the grand opening. They are of considerable international importance as they appear to be the earliest boats of any sort to have been built of wrought iron, the second earliest having been launched on the Forth & Clyde Canal in 1816. The earliest iron boat of all, built in 1787 and launched on
14036-431: Was managed as a separate project. It had its own entrance, by the tunnel entrance, and used water-powered machinery, driven by water flowing along the canal. The canal from Tavistock to the tunnel mouth, including an aqueduct which carried it over the River Lumburn , was opened in 1805. The 2,540-yard (2.32 km) tunnel was cut through rock, was of small bore, and required Taylor to construct two types of pump, one to keep
14157-447: Was marked by ships on the River Tamar firing a 21-gun salute. A "persistent legend" states that much of the construction work had been done by French prisoners of war , but the canal committee's annual account of construction progress makes no reference to this. The canal is unusual in that it was built with a gentle slope of about 1 ft per mile (20 cm per km). This was designed to attract industry to its banks, as it resulted in
14278-426: Was once used to describe linear features seen on the surface of Mars , Martian canals , an optical illusion. A navigation is a series of channels that run roughly parallel to the valley and stream bed of an unimproved river. A navigation always shares the drainage basin of the river. A vessel uses the calm parts of the river itself as well as improvements, traversing the same changes in height. A true canal
14399-489: Was restored to the Tamar in 1966, when the civil parishes of North Petherwin and Werrington were transferred from Devon to Cornwall. The Counties (Detached Parts) Act 1844 ensured parishes were entirely within one county. It transferred a part of the Rame Peninsula (on the west side of the Hamoaze ) from Devon to Cornwall (namely, parts of the parishes of Maker and St John ). The Act also transferred part of
14520-457: Was the speedy Tamar, which divides The Cornish and the Devonish confines; Through both whose borders swiftly downe it glides. And, meeting Plim, to Plimmouth thence declines: And Dart, nigh chockt with sands of tinny mines; From "Rivers of England" by Edmund Spenser The Alliterative Morte Arthure states that the mortal combat of King Arthur and Mordred took place close to
14641-484: Was £40,000, which included provision for testing any mineral lodes which were found during its construction, and the rights to those minerals, together with dues payable to the Duke for their extraction, were negotiated before the project began. An act of Parliament , the Tavistock Canal Act 1803 ( 43 Geo. 3 . c. cxxx), was obtained which gave the proprietors the power to raise £50,000 in £50 shares for
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