106-884: The Bocholt–Herentals Canal (also known locally as the Kempisch Kanaal or the Maas-Scheldekanaal ) is a canal in Belgium that links the Zuid-Willemsvaart at Bocholt with the Albert Canal in Herentals , with a length of slightly over 60 kilometres. It is one of the seven canals linking the rivers Meuse and Scheldt . During the Second World War the canal was an important launch point for Operation Market Garden . The canal
212-547: 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
318-510: 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
424-399: A lock has to be provided alongside the weir, or in a side channel, to provide for the passage of vessels. A river is thereby converted into a succession of fairly level reaches rising in steps up-stream, providing still-water navigation comparable to a canal; but it differs from a canal in the introduction of weirs for keeping up the water-level, in the provision for the regular discharge of
530-415: 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
636-496: 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
742-413: 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
848-431: A flood-dam or confined within continuous embankments on both sides. By placing these embankments somewhat back from the margin of the river-bed, a wide flood-channel is provided for the discharge of the river as soon as it overflows its banks, while leaving the natural channel unaltered for the ordinary flow. Low embankments may be sufficient where only exceptional summer floods have to be excluded from meadows. Occasionally
954-429: A high flood to places on the lower river, weir-keepers are enabled to fully open the movable weirs beforehand to permit the passage of the flood, and riparian inhabitants receive timely warning of the impending inundation. Where portions of a riverside town are situated below the maximum flood-level, or when it is important to protect land adjoining a river from inundations, the overflow of the river must be diverted into
1060-549: 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
1166-399: A moderate fall and a fair discharge at their lowest stage, for with a large fall the current presents a great impediment to up-stream navigation, and there are generally great variations in water level, and when the discharge becomes very small in the dry season. It is impossible to maintain a sufficient depth of water in the low-water channel. The possibility to secure uniformity of depth in
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#17327874504511272-581: 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
1378-407: A river by lowering the shoals obstructing the channel depends on the nature of the shoals. A soft shoal in the bed of a river is due to deposit from a diminution in velocity of flow, produced by a reduction in fall and by a widening of the channel, or to a loss in concentration of the scour of the main current in passing over from one concave bank to the next on the opposite side. The lowering of such
1484-476: A shoal by dredging merely effects a temporary deepening, for it soon forms again from the causes which produced it. The removal, moreover, of the rocky obstructions at rapids, though increasing the depth and equalizing the flow at these places, produces a lowering of the river above the rapids by facilitating the efflux, which may result in the appearance of fresh shoals at the low stage of the river. Where, however, narrow rocky reefs or other hard shoals stretch across
1590-440: A stream's natural bottom lands so that the bulk of such lands can be made available for agriculture. A third reason is flood control, with the idea of giving a stream a sufficiently large and deep channel so that flooding beyond those limits will be minimal or nonexistent, at least on a routine basis. One major reason is to reduce natural erosion ; as a natural waterway curves back and forth, it usually deposits sand and gravel on
1696-459: 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
1802-414: Is 33 meters, which means the canal consists of 10 locks . These locks mostly remain in their original condition, except for "Sas 10" which dates back to the 1930s. Due to significant differences in altitude, staircase locks were constructed up until "Sas 3" (1A, 2A, and 3A). They eventually fell out of favor, which meant the old locks fell into disuse. Conventional locks were built next to the old ones around
1908-422: 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
2014-399: Is avoided, as is the danger of breaches in the banks from an unusually high flood-rise and rapid flow, with their disastrous effects. A most serious objection to the formation of continuous, high embankments along rivers bringing down considerable quantities of detritus, especially near a place where their fall has been abruptly reduced by descending from mountain slopes onto alluvial plains,
2120-399: Is held back and released more slowly. The removal of obstructions, natural or artificial (e.g., trunks of trees, boulders and accumulations of gravel) from a river bed furnishes a simple and efficient means of increasing the discharging capacity of its channel. Such removals will consequently lower the height of floods upstream. Every impediment to the flow, in proportion to its extent, raises
2226-486: Is liable to be stopped during the descent of high floods, which in many cases rise above the locks; and it is necessarily arrested in cold climates on all rivers by long, severe frosts, and especially by ice. Many small rivers, like the Thames above its tidal limit, have been rendered navigable by canalization, and several fairly large rivers have thereby provided a good depth for vessels for considerable distances inland. Thus
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#17327874504512332-401: Is loss of wetlands . Wetlands are an excellent habitat for many forms of wildlife, and additionally serve as a "filter" for much of the world's surface fresh water. Another is the fact that channelized streams are almost invariably straightened. For example, the channelization of Florida's Kissimmee River has been cited as a cause contributing to the loss of wetlands. This straightening causes
2438-701: 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
2544-432: Is rapid near their source and gradually diminishes, with occasional irregularities, until, in traversing plains along the latter part of their course, their fall usually becomes quite gentle. Accordingly, in large basins, rivers in most cases begin as torrents with a very variable flow, and end as gently flowing rivers with a comparatively regular discharge. The irregular flow of rivers throughout their course forms one of
2650-599: 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
2756-418: 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
2862-452: 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
2968-544: Is the danger of their bed being raised by deposit, producing a rise in the flood-level, and necessitating a raising of the embankments if inundations are to be prevented. Longitudinal sections of the Po River, taken in 1874 and 1901, show that its bed was materially raised during this period from the confluence of the Ticino to below Caranella , despite the clearance of sediment effected by the rush through breaches. Therefore,
3074-480: Is the study of how rivers change their form over time. Fluvial geomorphology is the cumulation of a number of sciences including open channel hydraulics , sediment transport , hydrology , physical geology, and riparian ecology. River engineering practitioners attempt to understand fluvial geomorphology, implement a physical alteration, and maintain public safety. The size of rivers above any tidal limit and their average freshwater discharge are proportionate to
3180-448: Is thought to occur because of reduction in habitat, elimination of riffles and pools, greater fluctuation of stream levels and water temperature, and shifting substrates. The rate of recovery for a stream once it has been dredged is extremely slow, with many streams showing no significant recovery 30 to 40 years after the date of channelization. For the reasons cited above, in recent years stream channelization has been greatly curtailed in
3286-463: The Chariton River in northern Missouri , United States, found that the channelized section of the river contained only 13 species of fish, whereas the natural segment of the stream was home to 21 species of fish. The biomass of fish able to be caught in the dredged segments of the river was 80 percent less than in the natural parts of the same stream. This loss of fish diversity and abundance
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3392-658: 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
3498-543: 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
3604-545: 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
3710-617: The Rhine , the Danube and the Mississippi . River engineering works are only required to prevent changes in the course of the stream, to regulate its depth, and especially to fix the low-water channel and concentrate the flow in it, so as to increase as far as practicable the navigable depth at the lowest stage of the water level. Engineering works to increase the navigability of rivers can only be advantageously undertaken in large rivers with
3816-528: 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
3922-614: 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
4028-556: 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),
4134-404: 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
4240-604: The "alteration of the hydrologic characteristics of coastal and non-coastal waters, which in turn could cause degradation of water resources." River engineering has often resulted in unintended systematic responses, such as reduced habitat for fish and wildlife, and alterations of water temperature and sediment transport patterns. Beginning in the late 20th century, the river engineering discipline has been more focused on repairing hydromodified degradations and accounting for potential systematic response to planned alterations by considering fluvial geomorphology . Fluvial geomorphology
4346-471: 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
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4452-472: 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
4558-710: The 1920s (1N, 2N, and 3N). On 10 September 1944 British troops managed to capture bridge number 9 in Lommel intact. This cut off the retreat of German soldiers, who were heavily fighting a bit to the South, in Hechtel . In spite of fervent fighting the Germans could not recapture the bridge. For one week, the front line was on the canal, from Neerpelt to Lommel. On 17 September, British forces started Operation Market Garden from bridge number 9, dubbing it Joe's Bridge . Besides
4664-727: The Albert Canal and the Zuid-Willemsvaart, the canal also connects to some other canals; these were built soon after it, creating a network of canals in the Kempen area. Recently, the canal gained importance for recreation, given the increasing number of yachts on the canals of Belgium and the Netherlands. Berthings were created in Herentals, Geel-Ten Aard, Lommel-Kolonie and Neerpelt. Like on many waterways, each side of
4770-461: The Army Corps with EPA participation. Rivers whose discharge is liable to become quite small at their low stage, or which have a somewhat large fall, as is usual in the upper part of rivers, cannot be given an adequate depth for navigation purely by works which regulate the flow; their ordinary summer level has to be raised by impounding the flow with weirs at intervals across the channel, while
4876-590: 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
4982-785: 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
5088-486: The U.S., and in some instances even partially reversed. In 1990 the United States Government published a " no net loss of wetlands" policy, whereby a stream channelization project in one place must be offset by the creation of new wetlands in another, a process known as "mitigation." The major agency involved in the enforcement of this policy is the same Army Corps of Engineers, which for many years
5194-508: The available fall is exceptionally small, as in land originally reclaimed from the sea, such as the English Fenlands , and where, in consequence, the drainage is in a great measure artificial, straight channels have been formed for the rivers. Because of the perceived value in protecting these fertile, low-lying lands from inundation, additional straight channels have also been provided for the discharge of rainfall, known as drains in
5300-406: The bottom of a river and present obstacles to the erosion by the current of the soft materials forming the bed of the river above and below, their removal may result in permanent improvement by enabling the river to deepen its bed by natural scour. The capability of a river to provide a waterway for navigation during the summer or throughout the dry season depends on the depth that can be secured in
5406-582: The canal has a good quality cyclepath over the full length; these also are mainly meant for recreational use. 51°11′13″N 5°33′59″E / 51.1869°N 5.5664°E / 51.1869; 5.5664 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,
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#17327874504515512-436: 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
5618-418: 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
5724-462: 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
5830-404: The canalized Seine has secured a navigable depth of 10 1 ⁄ 2 feet (3.2 metres) from its tidal limit up to Paris, a distance of 135 miles, and a depth of 6 3 ⁄ 4 feet (2.06 metres) up to Montereau, 62 miles higher up. As rivers flow onward towards the sea, they experience a considerable diminution in their fall, and a progressive increase in the basin which they drain, owing to
5936-405: The channel as a whole, and in the case of a large river with a considerable flow it is very difficult to maintain a straight cut owing to the tendency of the current to erode the banks and form again a sinuous channel. Even if the cut is preserved by protecting the banks, it is liable to produce changes shoals and raise the flood-level in the channel just below its termination. Nevertheless, where
6042-480: The channel at the low stage by low-dipping cross dikes extending from the river banks down the slope and pointing slightly up-stream so as to direct the water flowing over them into a central channel. The needs of navigation may also require that a stable, continuous, navigable channel is prolonged from the navigable river to deep water at the mouth of the estuary . The interaction of river flow and tide needs to be modeled by computer or using scale models, moulded to
6148-496: The channel at the lowest stage. The problem in the dry season is the small discharge and deficiency in scour during this period. A typical solution is to restrict the width of the low-water channel, concentrate all of the flow in it, and also to fix its position so that it is scoured out every year by the floods which follow the deepest part of the bed along the line of the strongest current. This can be effected by closing subsidiary low-water channels with dikes across them, and narrowing
6254-469: 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
6360-493: The completion of the embankments, together with their raising, would only eventually aggravate the injuries of the inundations they have been designed to prevent, as the escape of floods from the raised river must occur sooner or later. In the UK, problems of flooding of domestic properties around the turn of the 21st century have been blamed on inadequate planning controls which have permitted development on floodplains. This exposes
6466-486: The course, characteristics, or flow of a river with the intention of producing some defined benefit. People have intervened in the natural course and behaviour of rivers since before recorded history—to manage the water resources , to protect against flooding , or to make passage along or across rivers easier. Since the Yuan Dynasty and Ancient Roman times, rivers have been used as a source of hydropower . From
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#17327874504516572-399: 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
6678-422: The embankments are raised high enough to retain the floods during most years, while provision is made for the escape of the rare, exceptionally high floods at special places in the embankments, where the scour of the issuing current is guarded against, and the inundation of the neighboring land is least injurious. In this manner, the increased cost of embankments raised above the highest flood-level of rare occurrence
6784-478: The extent of their basins and the amount of rain which, after falling over these basins, reaches the river channels in the bottom of the valleys, by which it is conveyed to the sea. The basin of a river is the expanse of country bounded by a watershed (called a "divide" in North America) over which rainfall flows down towards the river traversing the lowest part of the valley, whereas the rain falling on
6890-476: The far slope of the watershed flows away to another river draining an adjacent basin. River basins vary in extent according to the configuration of the country, ranging from the insignificant drainage areas of streams rising on high ground very near the coast and flowing straight down into the sea, up to immense tracts of great continents, where rivers rising on the slopes of mountain ranges far inland have to traverse vast stretches of valleys and plains before reaching
6996-554: The fens. Even extensive modification of the course of a river combined with an enlargement of its channel often produces only a limited reduction in flood damage. Consequently, such floodworks are only commensurate with the expenditure involved where significant assets (such as a town) are under threat. Additionally, even when successful, such floodworks may simply move the problem further downstream and threaten some other town. Recent floodworks in Europe have included restoration of natural floodplains and winding courses, so that floodwater
7102-670: 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,
7208-402: The flood-level upstream. Regulations for the management of rivers may include stringent prohibitions with regard to pollution , requirements for enlarging sluice-ways and the compulsory raising of their gates for the passage of floods, the removal of fish traps , which are frequently blocked up by leaves and floating rubbish, reduction in the number and width of bridge piers when rebuilt, and
7314-448: The flow, primarily for navigation purposes, although power generation is often an important factor. The former is known in the US as channelization and the latter is generally referred to as canalization . Reducing the length of the channel by substituting straight cuts for a winding course is the only way in which the effective fall can be increased. This involves some loss of capacity in
7420-462: 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
7526-458: The gradient or slope. When two rivers of different sizes have the same fall, the larger river has the quicker flow, as its retardation by friction against its bed and banks is less in proportion to its volume than is the case with the smaller river. The fall available in a section of a river approximately corresponds to the slope of the country it traverses; as rivers rise close to the highest part of their basins, generally in hilly regions, their fall
7632-400: The gradual reduction in fall, and, consequently, in the transporting force of the current. Accordingly, under ordinary conditions, most of the materials brought down from the high lands by torrential water courses are carried forward by the main river to the sea, or partially strewn over flat alluvial plains during floods; the size of the materials forming the bed of the river or borne along by
7738-418: The height of the floods at these places, can be ascertained. With the help of these records, and by observing the times and heights of the maximum rise of a particular flood at the stations on the various tributaries, the time of arrival and height of the top of the flood at any station on the main river can be predicted with remarkable accuracy two or more days beforehand. By communicating these particulars about
7844-741: 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 engineering River engineering is a discipline of civil engineering which studies human intervention in
7950-570: The influx of tributaries subject to different conditions, so that the Rhone below Lyon has a more uniform discharge than most rivers, as the summer floods of the Arve are counteracted to a great extent by the low stage of the Saône flowing into the Rhone at Lyon, which has its floods in the winter when the Arve, on the contrary, is low. Another serious obstacle encountered in river engineering consists in
8056-409: The inside of the corners where the water flows slowly, and cuts sand, gravel, subsoil , and precious topsoil from the outside corners where it flows rapidly due to a change in direction. Unlike sand and gravel, the topsoil that is eroded does not get deposited on the inside of the next corner of the river. It simply washes away. Channelization has several predictable and negative effects. One of them
8162-531: The large quantity of detritus they bring down in flood-time, derived mainly from the disintegration of the surface layers of the hills and slopes in the upper parts of the valleys by glaciers, frost and rain. The power of a current to transport materials varies with its velocity , so that torrents with a rapid fall near the sources of rivers can carry down rocks, boulders and large stones , which are by degrees ground by attrition in their onward course into slate , gravel , sand and silt , simultaneously with
8268-529: The late 20th century, the practice of river engineering has responded to environmental concerns broader than immediate human benefit. Some river engineering projects have focused exclusively on the restoration or protection of natural characteristics and habitats . Hydromodification encompasses the systematic response to alterations to riverine and non-riverine water bodies such as coastal waters ( estuaries and bays ) and lakes. The U.S. Environmental Protection Agency (EPA) has defined hydromodification as
8374-470: The level of the river above it so as to produce the additional artificial fall necessary to convey the flow through the restricted channel, thereby reducing the total available fall. Human intervention sometimes inadvertently modifies the course or characteristics of a river, for example by introducing obstructions such as mining refuse, sluice gates for mills, fish-traps, unduly wide piers for bridges and solid weirs . By impeding flow these measures can raise
8480-549: 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
8586-480: 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
8692-534: 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
8798-466: The main difficulties in devising works for mitigating inundations or for increasing the navigable capabilities of rivers. In tropical countries subject to periodical rains, the rivers are in flood during the rainy season and have hardly any flow during the rest of the year, while in temperate regions, where the rainfall is more evenly distributed throughout the year, evaporation causes the available rainfall to be much less in hot summer weather than in
8904-541: The most heavily channelized areas in the United States is West Tennessee , where every major stream with one exception (the Hatchie River ) has been partially or completely channelized. Channelization of a stream may be undertaken for several reasons. One is to make a stream more suitable for navigation or for navigation by larger vessels with deep draughts. Another is to restrict water to a certain area of
9010-462: The national territory, in exchange for Luyksgestel , this removed the last obstacle. The canal was created by one Kümmer starting in 1843, construction took three years. The canal connected to the Zuid-Willemsvaart near Bocholt and to the river Nete near Herentals . Apart from its transportation function, the canal also served to irrigate the dry Kempen region with water from the Meuse. The canal
9116-506: 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
9222-407: The ocean. The size of the largest river basin of any country depends on the extent of the continent in which it is situated, its position in relation to the hilly regions in which rivers generally arise and the sea into which they flow, and the distance between the source and the outlet into the sea of the river draining it. The rate of flow of rivers depends mainly upon their fall, also known as
9328-604: 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
9434-630: The properties on the floodplain to flood, and the substitution of concrete for natural strata speeds the run-off of water, which increases the danger of flooding downstream. In the Midwestern United States and the Southern United States the term for this measure is channelization. Much of it was done under the auspices or overall direction of the United States Army Corps of Engineers . One of
9540-450: The river at the weirs, and in the two sills of the locks being laid at the same level instead of the upper sill being raised above the lower one to the extent of the rise at the lock, as usual on canals. Canalization secures a definite available depth for navigation; and the discharge of the river generally is amply sufficient for maintaining the impounded water level, as well as providing the necessary water for locking. Navigation, however,
9646-629: The rivers are high and subject to occasional heavy floods after a considerable rainfall during the cold period in most years. The only exceptions are rivers which have their sources amongst mountains clad with perpetual snow and are fed by glaciers ; their floods occur in the summer from the melting of snow and ice, as exemplified by the Rhône above the Lake of Geneva , and the Arve which joins it below. But even these rivers are liable to have their flow modified by
9752-480: 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
9858-468: The stream is gradually reduced on proceeding seawards, so that in the Po River in Italy, for instance, pebbles and gravel are found for about 140 miles below Turin , sand along the next 100 miles, and silt and mud in the last 110 miles (176 km). Improvements can be divided into those that are aimed at improving the flow of the river, particularly in flood conditions, and those that aim to hold back
9964-541: The streams to flow more rapidly, which can, in some instances, vastly increase soil erosion. It can also increase flooding downstream from the channelized area, as larger volumes of water traveling more rapidly than normal can reach choke points over a shorter period of time than they otherwise would, with a net effect of flood control in one area coming at the expense of greatly aggravated flooding in another. In addition, studies have shown that stream channelization results in declines of river fish populations. A 1971 study of
10070-414: The substitution of movable weirs for solid weirs. By installing gauges in a fairly large river and its tributaries at suitable points, and keeping continuous records for some time of the heights of the water at the various stations, the rise of the floods in the different tributaries, the periods they take in passing down to definite stations on the main river, and the influence they severally exercise on
10176-411: The successive influx of their various tributaries. Thus, their current gradually becomes more gentle and their discharge larger in volume and less subject to abrupt variations; and, consequently, they become more suitable for navigation. Eventually, large rivers, under favorable conditions, often furnish important natural highways for inland navigation in the lower portion of their course, as, for instance,
10282-573: 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
10388-460: The winter months, so that the rivers fall to their low stage in the summer and are very liable to be in flood in the winter. In fact, with a temperate climate, the year may be divided into a warm and a cold season, extending from May to October and from November to April in the Northern hemisphere respectively; the rivers are low and moderate floods are of rare occurrence during the warm period, and
10494-466: 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
10600-458: 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
10706-563: Was created as part of the link from the river Scheldt to the Meuse that Napoleon Bonaparte planned as the Grand Canal du Nord , but only the stretches Lommel - Beringen en Venlo - Neuss were built, with a part of the present Zuid-Willemsvaart between Lanaken and Bocholt . Linking the Scheldt with the Meuse remained important though, to serve the heavy industry in and around Liège . The 1807 Treaty of Fontainebleau added Lommel to
10812-550: Was enlarged, both in width and in draught, in 1928. As a link between Scheldt and Meuse, the canal lost much of its importance when the Albert Canal was opened in 1940: this was shorter and faster, and offered greater capacity. Some industry had already been settled however, and was to stay: one example is the Umicore (Union Minière) zinc works in Overpelt , dating from 1888. The difference in height between Bocholt and Herentals
10918-407: 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
11024-424: 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
11130-426: 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
11236-735: Was the primary promoter of wide-scale channelization. Often, in the instances where channelization is permitted, boulders may be installed in the bed of the new channel so that water velocity is slowed, and channels may be deliberately curved as well. In 1990 the U.S. Congress gave the Army Corps a specific mandate to include environmental protection in its mission, and in 1996 it authorized the Corps to undertake restoration projects. The U.S. Clean Water Act regulates certain aspects of channelization by requiring non-Federal entities (i.e. state and local governments, private parties) to obtain permits for dredging and filling operations. Permits are issued by
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