page_title: Canal
section_title: Middle Ages
hierarchical_section_title: Canal / History / Middle Ages
caption_attribution_description: English: It is a view of Thal Canal from a bridge in Mianwali city.
context_page_description: Canals are waterways channels, or artificial waterways, for water conveyance, or to service water transport vehicles. They may also help with irrigation. It can be thought of as an artificial version of a river.
  In most cases, the engineered works will have 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 is also known as a navigation when it parallels a river and shares part of its waters 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.
  In contrast, a canal cuts across a drainage divide atop a ridge, generally requiring an external water source above the highest elevation.
  Many canals have been built at elevations towering over valleys and other water ways crossing far below.
  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.
context_section_description: 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 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 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 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 the Naviglio Grande built between 1127 and 1257 to connect Milan with the Ticino River. 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 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 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.
caption: Thal Canal, Punjab, Pakistan.
exif: {"Image ImageDescription": "OLYMPUS DIGITAL CAMERA", "Image Make": "OLYMPUS_IMAGING_CORP.", "Image Model": "X450,D535Z,C370Z", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "1.4", "Image DateTime": "2053:04:21 09:56:46", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "568", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 50, 53, 48, 0, 0, 20, 0, 1, 0, 20, 0, ... ]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "2284", "Thumbnail JPEGInterchangeFormatLength": "9257", "EXIF ExposureTime": "71/50000", "EXIF FNumber": "41/10", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "64", "EXIF ExifVersion": "0221", "EXIF DateTimeOriginal": "2053:04:21 09:56:46", "EXIF DateTimeDigitized": "2053:04:21 09:56:46", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "307/100", "EXIF MeteringMode": "CenterWeightedAverage", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "29/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "640", "EXIF ExifImageLength": "480", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "2160", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal"}