Canal

A canal can cut across a drainage divide atop a ridge, generally requiring an external water source above the highest elevation.

The movement of bulk raw materials such as coal and ores—practically a prerequisite for further urbanization and industrialization—were difficult and only marginally affordable to move without water transport.

Their replacement was gradual, beginning first in the United Kingdom in the 1840s, where canal shipping was first augmented by, and later superseded by the much faster, less geographically constrained, and generally cheaper to maintain railways.

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.

Taking water from existing rivers or springs was an option in some cases, sometimes supplemented by other methods to deal with seasonal variations in flow.

These feature 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.

A mule can carry an eighth-ton[4] [250 pounds (113 kg)] maximum load over a journey measured in days and weeks,[4] though much more for shorter distances and periods with appropriate rest.

[6] In ancient China, large canals for river transport were established as far back as the Spring and Autumn period (8th–5th centuries BC), 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.

[7] 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.

But if 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.

[14] 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.

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 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.

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.

The first artificial canal in Western Europe was the Fossa Carolina built at the end of the 8th century under personal supervision of Charlemagne.

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.

In 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.

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.

It came into being because the Industrial Revolution (which began in Britain during the mid-18th century) demanded an economic and reliable way to transport goods and commodities in large quantities.

In Staffordshire the famous potter Josiah Wedgwood saw an opportunity to bring bulky cargoes of clay to his factory doors and to transport his fragile finished goods to market in Manchester, Birmingham or further away, by water, minimizing breakages.

The Erie Canal with its easy connections to most of the U.S. mid-west and New York City soon quickly paid back all its invested capital (US$7 million) and started turning a profit.

For example, Lowell, Massachusetts, considered to be "The Cradle of the American Industrial Revolution," has 6 miles (9.7 km) of canals, built from around 1790 to 1850, that provided water power and a means of transportation for the city.

The canals caused price convergence between different regions because of their reduction in transportation costs, which allowed Americans to ship and buy goods from farther distances much cheaper.

In France, a steady linking of all the river systems – Rhine, Rhône, Saône and Seine – and the North Sea was boosted in 1879 by the establishment of the Freycinet gauge, which specified the minimum size of locks.

Twenty years later, an expansionist United States, that just acquired colonies after defeating Spain in the 1898 Spanish–American War, and whose Navy became more important, decided to reactivate the project.

[34] The narrow early industrial canals, however, have ceased to carry significant amounts of trade and many have been abandoned to navigation, but may still be used as a system for transportation of untreated water.

Canals have found another use in the 21st century, as easements for the installation of fibre optic telecommunications network cabling, avoiding having them buried in roadways while facilitating access and reducing the hazard of being damaged from digging equipment.

An extensive canal system exists within the Imperial Valley in the Southern California desert to provide irrigation to agriculture within the area.

Suzhou was dubbed the "Venice of the East" by Marco Polo during his travels there in the 13th century, with its modern canalside Pingjiang Road and Shantang Street becoming major tourist attractions.

Other cities with extensive canal networks include: Alkmaar, Amersfoort, Bolsward, Brielle, Delft, Den Bosch, Dokkum, Dordrecht, Enkhuizen, Franeker, Gouda, Haarlem, Harlingen, Leeuwarden, Leiden, Sneek and Utrecht in the Netherlands; Brugge and Gent in Flanders, Belgium; Birmingham in England; Saint Petersburg in Russia; Bydgoszcz, Gdańsk, Szczecin and Wrocław in Poland; Aveiro in Portugal; Hamburg and Berlin in Germany; Fort Lauderdale and Cape Coral in Florida, United States, Wenzhou in China, Cần Thơ in Vietnam, Bangkok in Thailand, and Lahore in Pakistan.