Ancient Monuments

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Canal, lock, island and salmon keeping pond known collectively as the Tamar Canal

A Scheduled Monument in Calstock, Cornwall

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Latitude: 50.5179 / 50°31'4"N

Longitude: -4.2075 / 4°12'27"W

OS Eastings: 243598.804665

OS Northings: 71002.388699

OS Grid: SX435710

Mapcode National: GBR NS.JR31

Mapcode Global: FRA 272P.GNL

Entry Name: Canal, lock, island and salmon keeping pond known collectively as the Tamar Canal

Scheduled Date: 23 February 1976

Source: Historic England

Source ID: 1007302

English Heritage Legacy ID: CO 984

County: Cornwall

Civil Parish: Calstock

Traditional County: Cornwall

Lieutenancy Area (Ceremonial County): Cornwall

Church of England Parish: Calstock

Church of England Diocese: Truro


Thr monument includes a canal basin, lock, island and salmon-keeping pond associated with a weir on the River Tamar at Gunnislake. The island survives as a low lying area between the canal basin and the River Tamar which contains the salmon-keeping pond and was produced by the construction of a canal to allow navigation upstream beyond the weir. The canal has a relatively wide stone-built basin of about 25m long with narrow lock and partially surviving gates and winding gear to the south. The northern end has granite-built walls but no surviving gates. The salmon-keeping pond was built to provide an extra income from management of the salmon stocks in the river which might otherwise have been disrupted by the weir and canal.

Built by the Tamar Coal Manure and General Mercantile Company the canal was designed to carry agricultural fertilizers, in this case lime, inland. The River Tamar had been navigable since the 12th century as far as Morwellham but there were proposals in 1796 to build a public Devonshire Canal to provide a tub boat canal which would link with the Bude Canal in north Cornwall and Devon, incorporating both navigable river stretches and canals. This was never completed and the Tamar river section was only improved for a distance of 2.75 miles. The canal did support major industries including the Bone Manure works, Bealswood Brickworks and Gunnislake Gasworks up until 1914. According to the 1881 census six or more sea going vessels were tied up at the quays upstream. These quays supported two lime kilns, a large mine, two quarries and other industrial features and linked them to the sea enabling export. The company owning the canal was liquidated in 1942. The canal is known locally as the 'Tamar Manure Navigation'. It closed for commercial traffic in around 1929.

The lock and weir head are listed Grade II (60893) and the lock keeper's cottage (excluded from the scheduling) is also Listed Grade II (60892).

Sources: HER:-
PastScape Monument No:-438034

Source: Historic England

Reasons for Scheduling

Inland navigation using rivers originated in Britain in the prehistoric period and continues in use to the present day. From the Roman period, both canals (artificial waterways constructed primarily for navigation purposes) and river navigations (improvements to existing waterways to make navigation easier) were constructed, and medieval canals such as the navigable dykes dug by the monks in Holderness or the Exeter Canal are known. The full advantages of canals and inland waterways for the inexpensive and safe transportation of heavy, bulky or fragile goods were not recognised commercially in England until 1759 when the principal age of canal building began with the construction of the Bridgewater Canal by James Brindley, which opened in 1761. Canal construction brought with it the requirement for a whole range of associated structures. Many of these, such as bridges, canal workers' houses, warehouses, wet docks, dry docks, locks and water management systems involved the development of such structures and introduced the need for major technological innovation. The great age of canals lasted until about the 1840s, when their utility was eroded by the huge expansion of railways with their quick and cheap transportation of people and goods. During their relatively brief period of use, however, canals became the most important method of industrial transportation, making a major contribution to England's Industrial Revolution. The canal, lock, island and salmon keeping pond known collectively as the Tamar Canal survive well and were vital for enabling sea going transport to many industries in the area. Although originally designed as part of a much more ambitious scheme which was never completed this particular section was of major significance and facilitated commercial access to markets on a global scale. The surviving portions will contain archaeological and environmental evidence relating to the construction, function, social, political and economic significance of this important maritime link and the agricultural and industrial dependencies placed on it.

Source: Historic England

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