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90-678: The Tarbela Dam is located on the Indus River near the village of Tarbela in Bara, approximately 30 kilometers from the town of Attock. Positioned where the Indus River emerges from the foothills of the Himalayas and enters the Potwar Plateau, the dam features a reservoir for water storage. The average annual flow available is 101 billion cubic meters (3221 m/sec). It stands 143 meters tall and covers an area of 243 square kilometers. It has

180-540: 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

270-419: 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

360-589: 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

450-426: 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

540-494: 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

630-638: A discharge capacity of 18,406 cubic metres per second (650,000 cu ft/s) and the auxiliary spillway, 24,070 cubic metres per second (850,000 cu ft/s). Annually, over 70% of water discharged at Tarbela passes over the spillways and is not used for hydropower generation. Five large tunnels were constructed as part of the outlet works . Hydroelectricity is generated from turbines in tunnel 1 through 3, while tunnels 4 and 5 were designed for irrigation use. Both tunnels are to be converted to hydropower tunnels to increase Tarbela's electricity-generating capacity. These tunnels were originally used to divert

720-416: 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

810-409: 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

900-424: 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

990-708: 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,

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1080-424: 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

1170-711: A small discharge to each plant. Micro-irrigation uses less pressure and water flow than sprinkler irrigation. Drip irrigation delivers water directly to 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

1260-421: A storage capacity of 11.9 billion cubic meters of water and has nine gates to control the outflow of water. The dam was completed in 1976 and was designed to utilize water from the Indus River for irrigation , flood control , and the generation of hydroelectric power by storing flows during the monsoon period while subsequently releasing stored water during the low flow period in winter. The installed capacity of

1350-420: A surface area of 250 square kilometres (97 sq mi). The reservoir initially stored 11,600,000 acre-feet (14.3 km) of water, with a live storage of 9,700,000 acre-feet (12.0 km), though this figure has been reduced over the subsequent 35 years of operation to 6,800,000 acre-feet (8.4 km) due to silting. The maximum elevation of the reservoir is 1,550 ft (470 m) above MSL and

1440-399: 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

1530-480: 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

1620-503: 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

1710-441: Is also employed to protect crops from frost , suppress weed growth in grain fields, and prevent soil consolidation . It is also used to cool livestock , reduce dust , dispose of sewage , and support mining operations. Drainage , which involves the removal of surface and sub-surface water from a given location, is often studied in conjunction with irrigation. There are several methods of irrigation that differ in how water

1800-415: 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

1890-422: 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

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1980-422: 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

2070-457: 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

2160-621: Is discharged over spillways, while only a portion of the remaining 30% is used for hydropower generation. The Water and Power Development Authority in Pakistan says the third and last unit at its 1,410-MW Tarbela 4th Extension Hydropower Project has been synchronized with the National Grid. With this extension, the installed capacity of the Tarbela Hydel Power Station has increased to 4,888 MW. The project's cost

2250-424: 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

2340-419: 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. Salini Impregilo Webuild SpA (formerly Salini Impregilo SpA ; Italian: [saˈliːni impreˈdʒiːlo] ) is an Italian industrial group specialising in construction and civil engineering . The company was formally founded in 2014 as

2430-421: 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

2520-443: 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

2610-492: Is organised into four business areas: Dams, hydroelectric plants and hydraulic works; Motorways and airports; Railways and undergrounds; Civil and industrial buildings. The company's projects include 257 dams and hydroelectric plants; 6,830 kilometres (4,240 miles) of railway lines; 1,450 kilometres (900 miles) of underground works, 400 of which subway lines; 51,660 kilometres (32,100 miles) of roads and highways; and 350 bridges and viaducts. The sustainability rating assigned to

2700-422: 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

2790-586: 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

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2880-478: 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

2970-437: 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

3060-419: Is supplied to plants. Surface irrigation , also known as gravity irrigation, 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

3150-432: Is the practice of applying controlled amounts of water to land to help grow crops , landscape plants , and lawns . Irrigation has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation

3240-583: 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

3330-556: 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

3420-551: The Hazara Division within the Khyber Pakhtunkhwa province of Pakistan . The main dam wall, built of earth and rock fill, stretches 2,743 metres (8,999 ft) from the island to river right, standing 148 metres (486 ft) high. A pair of concrete auxiliary dams spans the river from the island to river left. The dam's two spillways are on the auxiliary dams rather than the main dam. The main spillway has

3510-541: The Siran River near Tarbela . Tarbela Dam was constructed as part of the Indus Basin Project after signing of the 1960 Indus Waters Treaty between India and Pakistan . The purpose was to compensate for the loss of water supplies of the eastern rivers ( Ravi , Sutlej and Beas ) that were designated for exclusive use by India per terms of the treaty. By the mid-1970s, power generation capacity

3600-577: 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

3690-573: 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

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3780-544: The 4,888 MW Tarbela hydroelectric power stations will increase to 6,418 MW after completion of the planned fifth extension financed by Asian Infrastructure Investment Bank and the World Bank . Then, it will be the 12th largest hydroelectric dam in the world, for electricity production capacity. The dam is at a narrow spot in the Indus River valley, named after the town of Tarbela in the Haripur District of

3870-417: The Indus River while the dam was being constructed. MA hydroelectric power plant on the right side of the main dam houses 14 generators fed with water from outlet tunnels 1, 2, and 3. There are four 175 MW generators on tunnel 1, six 175 MW generators on tunnel 2, and four 432 MW generators on tunnel 3, for a total generating capacity of 3,478 MW. Tarbela Reservoir is 80.5 kilometres (50.0 mi) long, with

3960-509: The Indus river remained diverted through the diversion channel. By the end of construction works in stage 2, tunnels had been built for diversion purposes. Stage 2 construction took 3 years to complete. Under the third stage of construction, works were carried out on the closure of the diversion channel and construction of the dam in that portion while the river was made to flow through diversion tunnels. The remaining portion of upstream blanket and

4050-760: The International Bank for Reconstruction and Development (IBRD), with a variable spread and 20-year maturity, including a six-year grace period. This will be the first World Bank-supported project in South Asia to be jointly financed with the Asian Infrastructure Investment Bank (AIIB) which will be providing $ 300m and the Government of Pakistan $ 133.5m. The total cost of the project is $ 823.5m. Irrigation Irrigation (also referred to as watering of plants )

4140-760: 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

4230-653: The Tarbela Reservoir or in adjacent higher valleys. For the land and built-up property acquired under the Land Acquisition Act of 1984, a cash compensation of Rs 469.65 million was paid to those affected. In the absence of a national policy, the resettlement concerns of the people displaced by the Tarbela Dam were addressed on an ad hoc basis. In 2011, many such people had still not been resettled or given land in compensation for their losses by

4320-522: The World Bank's International Bank for Reconstruction and Development . Pakistan's Water and Power Development Authority was to provide the remaining $ 74 million required for construction, before the project's cost was downwardly revised by $ 277 million. Interest costs for the loans are estimated to cost $ 83.5 million. Because of revised lower costs to $ 651 million from $ 928 million, the World Bank permitted Pakistani officials to expedite completion of

4410-518: The board approved Salini’s offer to buy the rest of Impregilo. Pietro Salini became chief executive. A few months later, the board approved Salini’s plan. In 2013, Salini launched a tender offer to buy the remaining ordinary shares in Impregilo. In January 2014 the transaction was completed forming Salini Impregilo. In 2016, it acquires Lane Industries, based in Connecticut . In May 2020,

4500-469: 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

4590-485: 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

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4680-589: The company was rebranded as Webuild. In November 2020, Webuild acquired a 65% shareholding in Astaldi . In November 2022, Webuild announced that, subject to due diligence, it would acquire the Australian based company Clough Group . The company undertakes the following types of works: dams, hydroelectric power plants, railways, tunnels, undergrounds, bridges, viaducts, highways, roads, ports, airports and prestigious residential and office complexes. The group

4770-711: 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

4860-408: 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

4950-410: 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

5040-502: 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

5130-610: The fifth phase extension will use the second irrigation tunnel. Pakistan's Water and Power Development Authority sought expressions of interest for the Tarbela-V Extension Project in August 2014, and was given final consent for construction in September 2015. The hydropower project of tunnel 5 has two major components: power generation facilities and power evacuation facilities. The major works included under

5220-519: The following year. The acquisition set a precedent in Italy because it was the first proxy fight for control of a company to occur in the country. Despite the opposition it faced from a group of investors, Salini managed to convince enough shareholders at an assembly in July 2012 to approve its proposal to replace Impregilo’s board of directors with its own list of candidates. Once in place, these new members of

5310-526: The government of Pakistan, in accordance with its contractual obligations with the World Bank. Because the source of the Indus River is glacial meltwater from the Himalayas , the river carries huge amounts of sediment , with an annual suspended sediment load of 200 million tons. Live storage capacity of Tarbela reservoir had declined more than 33.5 per cent to 6.434 million acre feet (MAF) against its original capacity of 9.679 MAF because of sedimentation over

5400-534: 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

5490-409: 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

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5580-482: The installation of three turbines with a capacity of 510 MW each in Tarbela's fifth tunnel which was previously dedicated to agricultural use. Upon completion, the total power generating capacity of Tarbela Dam will increase to 6,418 MW. In November 2015, the World Bank affirmed that it would finance at least $ 326 million of the project's estimated $ 796 million cost which includes $ 126 million of funding that

5670-490: 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

5760-399: 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

5850-441: 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

5940-407: The main dam at higher levels was also completed as part of stage 3 works, which were concluded in 1976. An area of about 260 square kilometers and about 82,000 acres (33,000 ha) of land was acquired for construction. The large reservoir of the dam submerged 135 villages, which resulted in the displacement of a population of about 96,000 people, many of whom were relocated to townships surrounding

6030-531: The minimum operating elevation is 1,392 ft (424 m) above MSL. The catchment area upriver of the Tarbela Dam is spread over 168,000 square kilometres (65,000 sq mi) of land largely supplemented by snow and glacier melt from the southern slopes of the Himalayas . There are two main Indus River tributaries upstream of the Tarbela Dam. These are the Shyok River , joining near Skardu , and

6120-435: 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

6210-436: 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

6300-614: The past 38 years. The useful life of the dam and reservoir was estimated to be approximately 50 years. However, sedimentation has been much lower than predicted, and it is now estimated that the useful lifespan of the dam will be 85 years, to about 2060. Pakistan plans to construct several large dams upstream of Tarbela, including the Diamer-Bhasha Dam . Upon completion of the Diamer-Bhasha dam, sediment loads into Tarbela will be decreased by 69%. In addition to fulfilling

6390-461: The primary purpose of the dam, i.e., supplying water for irrigation, Tarbela Power Station has generated 341.139 billion kWh of hydro-electric energy since commissioning. A record annual generation of 16.463 billion kWh was recorded during 1998–99. Annual generation during 2007–08 was 14.959 billion kWh while the station shared peak load of 3702 MW during the year, which was 23.057% of total WAPDA system peak. Tarbela dam extension-IV

6480-567: 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

6570-514: The project are modifications to tunnel 5 and building a new power house and its ancillaries to generate about 1,800GWh of power annually, a new 50 km of 500kV double-circuit transmission line from Tarbela to the Islamabad West Grid Station for power evacuation, and a new 500kV Islamabad West Grid Station. Construction commenced in August 2021 and will require an estimated 3.5 years for completion. The project will require

6660-498: The project by 8 months at a cost of an additional $ 51 million. Pakistani officials were also permitted to divert $ 126 million towards the Tarbela-V Extension Project . The Tarbela Dam was built with five original tunnels, with the first three dedicated to hydropower generation, and the remaining two slated for irrigation use. The fourth phase extension project uses the first of the two irrigation tunnels, while

6750-475: 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

6840-698: The result of the merger by incorporation of Salini into Impregilo. Webuild is the largest Italian engineering and general contractor group and a global player in the construction sector. The company is active in over 50 countries of 5 continents (Africa, America, Asia, Europe, Oceania) with more than 85,000 employees. Its experience ranges from the construction of dams, hydroelectric plants and hydraulic structures, water infrastructures and ports, to roads, motorways, railways, metro systems and underground works, to airports, hospitals and public and industrial buildings, to civil engineering for waste-to-energy plants and environmental protection initiatives. It takes first place in

6930-445: The right bank where a 1,500 feet (460 meters) long and 694.8 feet (211.8 meters) wide diversion channel was being excavated along with a 105 feet (32 meters) high buttress dam that was also being constructed. Stage 1 construction lasted approximately 2½ years. The main embankment dam and the upstream blanket were constructed across the main valley of the river Indus as part of the second stage of construction. During this time, water from

7020-400: 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

7110-493: 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

7200-812: 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

7290-610: The water sector of the Engineering News-Record rankings, the benchmark for the entire construction industry. The company is listed on the Borsa Italiana . It is directed by Pietro Salini . The company was founded as Impregilo in 1959 and expanded following a merger with Cogefar-Impresit S.p.A., Girola S.p.A. and Lodigiani S.p.A. in 1990. In 2011 Salini, privately held, began its acquisition of Impregilo with an initial purchase of shares, reaching 25%

7380-405: 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

7470-414: 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

7560-413: 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

7650-501: Was added in three subsequent hydro-electrical project extensions which were completed in 1992, installing a total of 3,478 MW generating capacity. Construction of Tarbela Dam was carried out in three stages to meet the diversion requirements of the river. Construction was undertaken by the Italian firm Salini Impregilo . In the first stage, the Indus River was allowed to flow in its natural channel, while construction works commenced on

7740-564: Was completed in February 2018. This project was constructed on Tunnel No. 4 of Tarbela Dam. It consists of three turbine-generator units, each with a capacity of 470 MW. The project is expected to provide an average of 3.84 billion units of electricity annually to the National Grid. It is intended to help supplement electricity supply during the high-demand summer months. Annual benefits of the project were estimated at Rs. 30.7 billion. On an annual basis, over 70% of water passing through Tarbela

7830-411: Was diverted from the $ 840 million fourth phase extension project after costs for that project were revised downwards. In September 2016, the World Bank approved an additional financing of $ 390 million for the fifth extension hydropower project of Tarbela dam that will support the scaling up of the power generation capacity by adding 1,530 megawatts to the existing tunnel 5. The project will be financed by

7920-459: Was initially estimated to be $ 928 million, but the cost was revised downwards to $ 651 million. The World Bank had agreed to provide an $ 840 million loan for the project in June 2013. The loan had two components: The first is a $ 400 million International Development Association loan , which will be lent as a concessional loan at low interest rates. The second portion consists of a $ 440 million from

8010-666: 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

8100-521: Was planned in June, 2012, and PC-1 was developed for the project. US ambassador Richard Olson offered aid for construction of this project during his visit to Pakistan, in March, 2013. In September 2013, Pakistan's Water and Power Development Authority signed a Rs. 26.053 billion contract with Chinese firm Sinohydro and Germany's Voith Hydro for executing civil works on the 1,410 MW Tarbela-IV Extension Project. Construction commenced in February 2014, and

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