Misplaced Pages

#405594

76-579: The 1,576 kilometres (979 mi) long Kafue River is the longest river lying wholly within Zambia. Its water is used for irrigation and for generating hydroelectric power . It is the largest tributary of the Zambezi , and of Zambia 's principal rivers, it is the most central and the most urban . More than 50% of Zambia's population live in the Kafue River Basin and of these around 65% are urban. It has

152-521: A national monument . In the Copperbelt, water is taken from the river to irrigate small farms and market gardens . At Kitwe it changes course to the south-west and flows through forest and areas of flat rock over which it floods in the wet season, keeping to a channel about 50 m wide in the dry season. The river again develops intricate meanders and a maze of channels in a swampy floodplain, with oxbow lakes and lagoons. It flows 20 km west of

228-540: A ball drive, gear drive, or impact mechanism. Rotors can be designed to rotate in a full or partial circle. Guns are similar to rotors, except that they generally operate at very high pressures of 275 to 900 kPa (40 to 130 psi) and flows of 3 to 76 L/s (50 to 1200 US gal/min), usually with nozzle diameters in the range of 10 to 50 mm (0.5 to 1.9 in). Guns are used not only for irrigation, but also for industrial applications such as dust suppression and logging . Sprinklers can also be mounted on moving platforms connected to

304-419: A circular or semi-circular pattern. Traveling Sprinklers: These move along the hose path on their own, watering as they go, ideal for covering long, narrow spaces. Each type offers different advantages based on garden size and shape, water pressure, and specific watering needs. Subirrigation has been used for many years in field crops in areas with high water tables . It is a method of artificially raising

380-589: A clock or timer. Most automatic systems employ electric solenoid valves . Each zone has one or more of these valves that are wired to the controller. When the controller sends power to the valve, the valve opens, allowing water to flow to the sprinklers in that zone. There are two main types of sprinklers used in lawn irrigation, pop-up spray heads and rotors. Spray heads have a fixed spray pattern, while rotors have one or more streams that rotate. Spray heads are used to cover smaller areas, while rotors are used for larger areas. Golf course rotors are sometimes so large that

456-426: A computerized set of valves . In sprinkler or overhead irrigation, water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns. A system using sprinklers, sprays, or guns mounted overhead on permanently installed risers is often referred to as a solid-set irrigation system. Higher pressure sprinklers that rotate are called rotors and are driven by

532-459: A depth of less than a metre in the rainy season (deeper in some lagoons and permanently swampy areas), and drying out to a clayey black soil in the dry season. The Kafue Flats are the third major wildlife area of the river. Tens of thousands of Kafue Lechwe live on the Kafue Flats and are adapted to wading the flooded areas. This area also has one of the greatest variety and concentrations of birds in

608-494: A direct financial cost to the farmer. Irrigation often requires pumping energy (either electricity or fossil fuel) to deliver water to the field or supply the correct operating pressure. Hence increased efficiency will reduce both the water cost and energy cost per unit of agricultural production. A reduction of water use on one field may mean that the farmer is able to irrigate a larger area of land, increasing total agricultural production. Low efficiency usually means that excess water

684-416: A flood (spate), water is diverted to normally dry river beds (wadis) using a network of dams, gates and channels and spread over large areas. The moisture stored in the soil will be used thereafter to grow crops. Spate irrigation areas are in particular located in semi-arid or arid, mountainous regions. Micro-irrigation , sometimes called localized irrigation , low volume irrigation , or trickle irrigation

760-688: A full account. It was opened in 1906 to connect Kafue with Mazabuka and was originally meant to be part of the Cape to Cairo Railway . The first road bridge across the Kafue was originally built across the Thames in London during the Second World War. After the war, it was dismantled and installed some 9 km downstream from the railway bridge. Previously, road traffic crossed the river by pontoon. The T3 road crosses

836-409: A higher profit than potatoes. The land is flood irrigated twice a day to simulate tidal flooding; the water is pumped from the sea using wind power. Additional benefits are soil remediation and carbon sequestration . Until the 1960s, there were fewer than half the number of people on the planet as of 2024. People were not as wealthy as today, consumed fewer calories and ate less meat , so less water

SECTION 10

#1732844368406

912-519: A mean flow rate of 320 cubic metres per second (11,000 cu ft/s) through its lower half, with high seasonal variations. The river discharges 10 cubic kilometres (2.4 cu mi) per year into the Zambezi River . The Kafue River rises at an elevation of 1,350 metres (4,430 ft) on the relatively flat plateau just south the border between Zambia and the Democratic Republic of

988-424: A rectangular or square pattern. They are good for covering large, flat areas evenly. Impact (or Pulsating) Sprinklers: These create a rotating, pulsating spray, which can cover a circular or semi-circular area. They are useful for watering large lawns. Stationary Sprinklers: These have a fixed spray pattern and are best for smaller areas or gardens. Rotary Sprinklers: These use spinning arms to distribute water in

1064-708: A result of irrigation and the subsequent effects on natural and social conditions in river basins and downstream of an irrigation scheme . The effects stem from the altered hydrological conditions caused by the installation and operation of the irrigation scheme. Amongst some of these problems is depletion of underground aquifers through overdrafting . Soil can be over-irrigated due to poor distribution uniformity or management wastes water, chemicals, and may lead to water pollution . Over-irrigation can cause deep drainage from rising water tables that can lead to problems of irrigation salinity requiring watertable control by some form of subsurface land drainage . In 2000,

1140-424: A single sprinkler is combined with a valve and called a 'valve in head'. When used in a turf area, the sprinklers are installed with the top of the head flush with the ground surface. When the system is pressurized, the head will pop up out of the ground and water the desired area until the valve closes and shuts off that zone. Once there is no more pressure in the lateral line, the sprinkler head will retract back into

1216-405: A small reed platform about 3  square at the margin of the vegetation, with a tube in the center down to the water. They cover themselves and the tube with blankets, blocking out light as the adjacent vegetation does and enabling them to see the fish in the river clearly. They then spear the fish with bident and trident spears up to 6 m long, and occasionally longer, depending on the depth of

1292-533: A trickle from the marshy dambos (the Munyanshi Swamp is a tributary) and with little slope to speed up river flow, it meanders south-eastwards sluggishly and within 50 kilometres (31 mi) has the character of a mature river. The area receives about 1,200 millimetres (47 in) of rain in the rainy season, and the river's channel soon reaches 100 metres (330 ft) wide with a floodplain of fluvial dambos 1 to 2 kilometres (0.62 to 1.24 mi) wide. Before

1368-399: Is supplementary to rainfall as happens in many parts of the world, or whether it is ' full irrigation' whereby crops rarely depend on any contribution from rainfall. Full irrigation is less common and only happens in arid landscapes experiencing very low rainfall or when crops are grown in semi-arid areas outside of any rainy seasons. Surface irrigation, also known as gravity irrigation, is

1444-480: Is a form of sprinkler irrigation utilising several segments of pipe (usually galvanized steel or aluminium) joined and supported by trusses , mounted on wheeled towers with sprinklers positioned along its length. The system moves in a circular pattern and is fed with water from the pivot point at the center of the arc. These systems are found and used in all parts of the world and allow irrigation of all types of terrain. Newer systems have drop sprinkler heads as shown in

1520-503: Is a system where water is distributed under low pressure through a piped network, in a pre-determined pattern, and applied as a small discharge to each plant or adjacent to it. Traditional drip irrigation use individual emitters, subsurface drip irrigation (SDI), micro-spray or micro-sprinklers, and mini-bubbler irrigation all belong to this category of irrigation methods. Drip irrigation, also known as microirrigation or trickle irrigation, functions as its name suggests. In this system, water

1596-415: Is also the means of delivery of fertilizer. The process is known as fertigation . Deep percolation, where water moves below the root zone, can occur if a drip system is operated for too long or if the delivery rate is too high. Drip irrigation methods range from very high-tech and computerized to low-tech and labor-intensive. Lower water pressures are usually needed than for most other types of systems, with

SECTION 20

#1732844368406

1672-422: Is common in many parts of the world as rainfed agriculture , or it can be full irrigation, where crops rarely rely on any contribution from rainfall. Full irrigation is less common and only occurs in arid landscapes with very low rainfall or when crops are grown in semi-arid areas outside of rainy seasons. The environmental effects of irrigation relate to the changes in quantity and quality of soil and water as

1748-422: Is delivered at or near the root zone of plants, one drop at a time. This method can be the most water-efficient method of irrigation, if managed properly; evaporation and runoff are minimized. The field water efficiency of drip irrigation is typically in the range of 80 to 90% when managed correctly. In modern agriculture, drip irrigation is often combined with plastic mulch , further reducing evaporation, and

1824-457: Is dependent upon farmers having sufficient access to water. However, water scarcity is already a critical constraint to farming in many parts of the world. There are several methods of irrigation. They vary in how the water is supplied to the plants. The goal is to apply the water to the plants as uniformly as possible, so that each plant has the amount of water it needs, neither too much nor too little. Irrigation can also be understood whether it

1900-424: Is less expensive to install than a center pivot, but much more labor-intensive to operate – it does not travel automatically across the field: it applies water in a stationary strip, must be drained, and then rolled to a new strip. Most systems use 100 or 130 mm (4 or 5 inch) diameter aluminum pipe. The pipe doubles both as water transport and as an axle for rotating all the wheels. A drive system (often found near

1976-556: Is lost through seepage or runoff, both of which can result in loss of crop nutrients or pesticides with potential adverse impacts on the surrounding environment. Kafwe Twa The Twa of the Kafue Flats wetlands of Zambia are one of several fishing and hunter-gatherer castes living in a patron-client relationship with farming Bantu peoples across central and southern Africa. In Southern Province , where swampy terrain means that large-scale crops cannot be planted near

2052-421: Is often no alternative for farmers but to use water polluted with urban waste directly to water their crops. There can be significant health hazards related to using untreated wastewater in agriculture. Municipal wastewater can contain a mixture of chemical and biological pollutants. In low-income countries, there are often high levels of pathogens from excreta. In emerging nations , where industrial development

2128-443: Is often the irrigation choice for developing nations, for low value crops and for large fields. Where water levels from the irrigation source permit, the levels are controlled by dikes ( levees ), usually plugged by soil. This is often seen in terraced rice fields (rice paddies), where the method is used to flood or control the level of water in each distinct field. In some cases, the water is pumped, or lifted by human or animal power to

2204-422: Is outpacing environmental regulation, there are increasing risks from inorganic and organic chemicals. The World Health Organization developed guidelines for safe use of wastewater in 2006, advocating a ‘multiple-barrier' approach wastewater use, for example by encouraging farmers to adopt various risk-reducing behaviors. These include ceasing irrigation a few days before harvesting to allow pathogens to die off in

2280-581: Is practiced in the vineyards at Lanzarote using stones to condense water. Fog collectors are also made of canvas or foil sheets. Using condensate from air conditioning units as a water source is also becoming more popular in large urban areas. As of November 2019 a Glasgow-based startup has helped a farmer in Scotland to establish edible saltmarsh crops irrigated with sea water. An acre of previously marginal land has been put under cultivation to grow samphire , sea blite , and sea aster ; these plants yield

2356-478: Is similar in principle and action to subsurface basin irrigation. Another type of subirrigation is the self-watering container, also known as a sub-irrigated planter . This consists of a planter suspended over a reservoir with some type of wicking material such as a polyester rope. The water is drawn up the wick through capillary action. A similar technique is the wicking bed ; this too uses capillary action. Modern irrigation methods are efficient enough to supply

Kafue River - Misplaced Pages Continue

2432-437: Is supplied at one end using a large hose. After sufficient irrigation has been applied to one strip of the field, the hose is removed, the water drained from the system, and the assembly rolled either by hand or with a purpose-built mechanism, so that the sprinklers are moved to a different position across the field. The hose is reconnected. The process is repeated in a pattern until the whole field has been irrigated. This system

2508-496: Is the oldest form of irrigation and has been in use for thousands of years. In sprinkler irrigation , water is piped to one or more central locations within the field and distributed by overhead high-pressure water devices. Micro-irrigation is a system that distributes water under low pressure through a piped network and applies it as a small discharge to each plant. Micro-irrigation uses less pressure and water flow than sprinkler irrigation. Drip irrigation delivers water directly to

2584-583: Is used for irrigation in agriculture, the nutrient (nitrogen and phosphorus) content of the treated wastewater has the benefit of acting as a fertilizer . This can make the reuse of excreta contained in sewage attractive. In developing countries , agriculture is increasingly using untreated municipal wastewater for irrigation – often in an unsafe manner. Cities provide lucrative markets for fresh produce, so they are attractive to farmers. However, because agriculture has to compete for increasingly scarce water resources with industry and municipal users, there

2660-556: Is usually not considered as a form of irrigation. Rainwater harvesting is the collection of runoff water from roofs or unused land and the concentration of this. Irrigation with recycled municipal wastewater can also serve to fertilize plants if it contains nutrients, such as nitrogen, phosphorus and potassium. There are benefits of using recycled water for irrigation, including the lower cost compared to some other sources and consistency of supply regardless of season, climatic conditions and associated water restrictions. When reclaimed water

2736-590: The Itezhi-Tezhi Dam . Commercial plantations , especially those bordering the Kafue flats take large quantities of water for irrigation. Chief of these is the Nakambala Sugar Estate, which draws in excess of 720,000 m per day to irrigate 134.13 square kilometres of land to grow sugar cane. Irrigation There are several methods of irrigation that differ in how water is supplied to plants. Surface irrigation , also known as gravity irrigation,

2812-559: The United States , China , and European countries like the United Kingdom , also fund and organize some schemes within other nations. By 2021 the global land area equipped for irrigation reached 352 million ha, an increase of 22% from the 289 million ha of 2000 and more than twice the 1960s land area equipped for irrigation. The vast majority is located in Asia (70%), where irrigation

2888-573: The commercial greenhouse production, usually for potted plants . Water is delivered from below, absorbed by upwards, and the excess collected for recycling. Typically, a solution of water and nutrients floods a container or flows through a trough for a short period of time, 10–20 minutes, and is then pumped back into a holding tank for reuse. Sub-irrigation in greenhouses requires fairly sophisticated, expensive equipment and management. Advantages are water and nutrient conservation, and labor savings through reduced system maintenance and automation . It

2964-686: The Congo 120 kilometres (75 mi) north-west of Chingola in the Copperbelt Province . The source of the Kafue River is in the North-western Province of Zambia. The area is Miombo woodland on the Congo-Zambezi watershed, with many branching dambos lying 10 to 20 metres (33 to 66 ft) lower than the highest ground, producing a very gently undulating topography . The river starts as

3040-575: The Lukanga Swamp help silt and pollution settle out so that the river becomes clear downstream. A report in April 2002 said: … natural wetlands are quite effective at controlling water pollution from mining in the Copperbelt … Tests show the Kafue to be clean of mining pollutants downstream from the Copperbelt. In the Kafue flats , the discharge of phosphates in excess fertiliser run-off from commercial farming and

3116-567: The Nakambala Sugar Estate can cause algal blooms and weed growth, reducing fish populations. Effluent from mining containing cadmium, lead and mercury have degraded the Kafue River Municipal water supply had to be suspended when the Kafue River turned blue due to slurry discharge Because of its size and geographic location, the Kafue River basin is an ecosystem that provides services and support to communities and industries that have different and sometimes conflicting interests in usage of

Kafue River - Misplaced Pages Continue

3192-727: The Nile river in Egypt and Sudan; and in the Mississippi-Missouri river basin, the Southern Great Plains, and in parts of California in the United States. Smaller irrigation areas are spread across almost all populated parts of the world. By 2012, the area of irrigated land had increased to an estimated total of 3,242,917 km (801 million acres), which is nearly the size of India. The irrigation of 20% of farming land accounts for

3268-461: The Zambian Cabinet approved a revised National Water policy that "aims to improve water resources management by establishing institutional coordination, engaging in modern methods of integrated water resource management while decentralising government policy to address diverse interests within the water sector". These have had major negative environmental effects on the river — see main article on

3344-469: The center pivot. This type of system is known as LEPA (Low Energy Precision Application). Originally, most center pivots were water-powered. These were replaced by hydraulic systems ( T-L Irrigation ) and electric-motor-driven systems (Reinke, Valley, Zimmatic). Many modern pivots feature GPS devices. A series of pipes, each with a wheel of about 1.5 m diameter permanently affixed to its midpoint, and sprinklers along its length, are coupled together. Water

3420-485: The centre of the wheel line) rotates the clamped-together pipe sections as a single axle, rolling the whole wheel line. Manual adjustment of individual wheel positions may be necessary if the system becomes misaligned. Wheel line systems are limited in the amount of water they can carry, and limited in the height of crops that can be irrigated. One useful feature of a lateral move system is that it consists of sections that can be easily disconnected, adapting to field shape as

3496-711: The components of these irrigation systems are hidden under ground, since aesthetics are important in a landscape. A typical lawn sprinkler system will consist of one or more zones, limited in size by the capacity of the water source. Each zone will cover a designated portion of the landscape. Sections of the landscape will usually be divided by microclimate , type of plant material, and type of irrigation equipment. A landscape irrigation system may also include zones containing drip irrigation, bubblers, or other types of equipment besides sprinklers. Although manual systems are still used, most lawn sprinkler systems may be operated automatically using an irrigation controller , sometimes called

3572-408: The crop or field requirements. Increasing the application efficiency means that the amount of crop produced per unit of water increases. Improved efficiency may either be achieved by applying less water to an existing field or by using water more wisely thereby achieving higher yields in the same area of land. In some parts of the world, farmers are charged for irrigation water hence over-application has

3648-410: The entire field uniformly with water, so that each plant has the amount of water it needs, neither too much nor too little. Water use efficiency in the field can be determined as follows: Increased irrigation efficiency has a number of positive outcomes for the farmer, the community and the wider environment. Low application efficiency infers that the amount of water applied to the field is in excess of

3724-502: The exception of low-energy center pivot systems and surface irrigation systems, and the system can be designed for uniformity throughout a field or for precise water delivery to individual plants in a landscape containing a mix of plant species. Although it is difficult to regulate pressure on steep slopes, pressure compensating emitters are available, so the field does not have to be level. High-tech solutions involve precisely calibrated emitters located along lines of tubing that extend from

3800-534: The ground. In flower beds or shrub areas, sprinklers may be mounted on above ground risers or even taller pop-up sprinklers may be used and installed flush as in a lawn area. Hose-end sprinklers are devices attached to the end of a garden hose, used for watering lawns, gardens, or plants. They come in a variety of designs and styles, allowing you to adjust the water flow, pattern, and range for efficient irrigation. Some common types of hose-end sprinklers include: Oscillating Sprinklers: These spray water back and forth in

3876-409: The image that follows. As of 2017 most center pivot systems have drops hanging from a U-shaped pipe attached at the top of the pipe with sprinkler heads that are positioned a few feet (at most) above the crop, thus limiting evaporative losses. Drops can also be used with drag hoses or bubblers that deposit the water directly on the ground between crops. Crops are often planted in a circle to conform to

SECTION 50

#1732844368406

3952-490: The irrigation results in flooding or near flooding of the cultivated land. Historically, surface irrigation is the most common method of irrigating agricultural land across most parts of the world. The water application efficiency of surface irrigation is typically lower than other forms of irrigation, due in part to the lack of control of applied depths. Surface irrigation involves a significantly lower capital cost and energy requirement than pressurised irrigation systems. Hence it

4028-399: The level of the land. Surface irrigation is even used to water urban gardens in certain areas, for example, in and around Phoenix, Arizona . The irrigated area is surrounded by a berm and the water is delivered according to a schedule set by a local irrigation district . A special form of irrigation using surface water is spate irrigation , also called floodwater harvesting. In case of

4104-441: The line is moved. They are most often used for small, rectilinear, or oddly-shaped fields, hilly or mountainous regions, or in regions where labor is inexpensive. A lawn sprinkler system is permanently installed, as opposed to a hose-end sprinkler, which is portable. Sprinkler systems are installed in residential lawns, in commercial landscapes, for churches and schools, in public parks and cemeteries, and on golf courses . Most of

4180-601: The main rivers, only the Twa fish. They exchange their catch for agricultural produce from their Bantu/village patrons, the Tonga and perhaps the Ila , who build villages at the ecotone on the margins of the floodplain, which they call Butwa "Twa country". The Kafue Twa have a dark-hut method of fishing unique in Africa. The sides of the river are covered with a thick mat of vegetation. The Twa raise

4256-435: The oldest form of irrigation and has been in use for thousands of years. In surface ( furrow, flood , or level basin ) irrigation systems, water moves across the surface of agricultural lands, in order to wet it and infiltrate into the soil. Water moves by following gravity or the slope of the land. Surface irrigation can be subdivided into furrow, border strip or basin irrigation . It is often called flood irrigation when

4332-436: The overarching goal of increasing self-sufficiency. Irrigation water can come from groundwater (extracted from springs or by using wells ), from surface water (withdrawn from rivers , lakes or reservoirs ) or from non-conventional sources like treated wastewater , desalinated water , drainage water , or fog collection . While floodwater harvesting belongs to the accepted irrigation methods, rainwater harvesting

4408-471: The permanent part of the Lukanga Swamp which fills a circular depression, and which drains through a channel into the Kafue. The area between the swamp and river is flood plain and when that and surrounding areas are inundated in the rainy season, the combined wetland exceeds 6,000 km. This is the first of the three main wildlife areas of the river, and the least surveyed and protected. The character of

4484-567: The production of 40% of food production. The scale of irrigation increased dramatically over the 20th century. In 1800, 8 million hectares globally were irrigated, in 1950, 94 million hectares, and in 1990, 235 million hectares. By 1990, 30% of the global food production came from irrigated land. Irrigation techniques across the globe includes canals redirecting surface water, groundwater pumping, and diverting water from dams. National governments lead most irrigation schemes within their borders, but private investors and other nations, especially

4560-697: The rainy season the Lufupa floods the plain. Like the upper Zambezi, Okavango and Cuando rivers, the Kafue used to flow south all the way to Lake Makgadikgadi and on to the Limpopo River , but the land in that area was uplifted . A rift valley formed running due east of where the Kafue National Park is now, and the Kafue river eroded a channel called the Itezhi-Tezhi Gap through a ridge of hills about 100 m high, flowing eastwards. The Itezhi-Tezhi Dam

4636-470: The regions saw increases in the area equipped for irrigation, with Africa growing the fastest (+29%), followed by Asia (+25%), Oceania (+24%), the Americas (+19%) and Europe (+2%). Irrigation enables the production of more crops, especially commodity crops in areas which otherwise could not support them. Countries frequently invested in irrigation to increase wheat , rice , or cotton production, often with

SECTION 60

#1732844368406

4712-633: The river changes again, as it forms a less meandering dry-season channel with sandy banks and islands. Continuing south-west it enters the Kafue National Park , second largest national park in Africa, where it receives its two largest tributaries, the Lunga and Lufupa rivers, also from the north. The Kafue skirts the south-east edge of the Busanga Plain, one of Africa's premier wildlife areas, known for large herds of cape buffalo , zebra and antelope . In

4788-523: The river drops 550 metres (1,800 ft) over 60 kilometres (37 mi) through the Kafue Gorge . A second dam, the Kafue Gorge Dam , with a smaller reservoir, generates electricity. The lower Zambezi (originally a separate river) cut back through the rift valleys and eventually captured the Kafue. Their confluence is about 20 kilometres (12 mi) north of Chirundu . See Kafue Railway Bridge for

4864-552: The river in-between Chililabombwe and Chingola as well as in the city of Kitwe , both in the Copperbelt Province . The T2 road ( Cape to Cairo Road ) crosses the river 10 km south of the Kafue town centre. The Lusaka–Mongu Road crosses the river as the Kafue Hook Bridge in the Kafue National Park . As it flows through the Copperbelt the Kafue River is at great risk of pollution , not just from urban waste but from copper mine tailings . The swampy areas west of

4940-517: The river reaches the Copperbelt towns, however, it loses its wide floodplain, the channel narrows to 30–40 m and it meanders less, in a shallow valley only 40 m or so lower than the surrounding plateau. It flows close to the Copperbelt towns of Chililabombwe , Chingola and Mufulira , and through the outskirts of Kitwe . The popular picnic spot the Hippo Pool north of Chingola is protected as

5016-660: The river resources. In 1999, the World Wildlife Fund (WWF) initiated dialogue between the Zambian Government, the Zambia Electricity Supply Corporation (ZESCO) and local people to restore a more natural flow pattern to water releases from the Itezhi-Tezhi Dam built on the Kafue River. This project heavily influenced development of Zambian Government policy on water resources and in February 2010,

5092-555: The root zone of plants. Subirrigation has been used in field crops in areas with high water tables for many years. It involves artificially raising the water table to moisten the soil below the root zone of plants. Irrigation water can come from groundwater (extracted from springs or by using wells ), from surface water (withdrawn from rivers , lakes or reservoirs ) or from non-conventional sources like treated wastewater , desalinated water , drainage water , or fog collection . Irrigation can be supplementary to rainfall , which

5168-400: The sprinkler arrives back at the reel the system shuts off. This type of system is known to most people as a "waterreel" traveling irrigation sprinkler and they are used extensively for dust suppression, irrigation, and land application of waste water. Other travelers use a flat rubber hose that is dragged along behind while the sprinkler platform is pulled by a cable. Center pivot irrigation

5244-493: The sunlight; applying water carefully so it does not contaminate leaves likely to be eaten raw; cleaning vegetables with disinfectant; or allowing fecal sludge used in farming to dry before being used as a human manure. Irrigation water can also come from non-conventional sources like treated wastewater , desalinated water , drainage water , or fog collection . In countries where humid air sweeps through at night, water can be obtained by condensation onto cold surfaces. This

5320-733: The total fertile land was 2,788,000 km (689 million acres) and it was equipped with irrigation infrastructure worldwide. About 68% of this area is in Asia, 17% in the Americas, 9% in Europe, 5% in Africa and 1% in Oceania. The largest contiguous areas of high irrigation density are found in Northern and Eastern India and Pakistan along the Ganges and Indus rivers; in the Hai He, Huang He and Yangtze basins in China; along

5396-405: The water source by a hose. Automatically moving wheeled systems known as traveling sprinklers may irrigate areas such as small farms, sports fields, parks, pastures, and cemeteries unattended. Most of these use a length of polyethylene tubing wound on a steel drum. As the tubing is wound on the drum powered by the irrigation water or a small gas engine, the sprinkler is pulled across the field. When

5472-414: The water table to allow the soil to be moistened from below the plants' root zone. Often those systems are located on permanent grasslands in lowlands or river valleys and combined with drainage infrastructure. A system of pumping stations, canals, weirs and gates allows it to increase or decrease the water level in a network of ditches and thereby control the water table. Subirrigation is also used in

5548-399: The world. The Lochinvar and Blue Lagoon National Parks have been established on the flats. Around Mazabuka as the river gets closer to the town of Kafue , sugar plantations and other large agricultural estates have been established on the fertile black soil and use water from the river in the dry season. The Kafue Flats end at Kafue town and from there, as the rift valley gets deeper,

5624-413: Was a key component of the green revolution; the Americas account for 16% and Europe for 8% of the world total. India (76 million ha) and China (75 million ha) have the largest equipped area for irrigation, far ahead of the United States o fAmerica (27 million ha). China and India also have the largest net gains in equipped area between 2000 and 2020 (+21 million ha for China and +15 million ha for India). All

5700-548: Was built in 1977 at the gap and now forms a reservoir 50 km long and up to 10 km wide. Further east, the river flows sluggishly across a flat plain called the Kafue Flats (formerly Butwa after the Twa people ) and for the third time develops intricate meanders in a maze of swampy channels and lagoons. This time however it also has an immense shallow flood plain which no roads or railways cross, 240 kilometres (150 mi) long and about 50 kilometres (31 mi) wide, flooded to

5776-666: Was needed to produce their food. They required a third of the volume of water humans presently take from rivers. Today, the competition for water resources is much more intense, because there are now more than seven billion people on the planet, increasing the likelihood of overconsumption of food produced by water-thirsty animal agriculture and intensive farming practices. This creates increasing competition for water from industry , urbanisation and biofuel crops . Farmers will have to strive to increase productivity to meet growing demands for food , while industry and cities find ways to use water more efficiently. Successful agriculture

#405594