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Groundwater Exploitation
Overdrafting is the process of extracting groundwater beyond the equilibrium yield of an aquifer. Groundwater is one of the largest sources of fresh water and is found underground. Groundwater depletion is comparable to a bank account in which more money is withdrawn than deposited. The primary cause of groundwater depletion is the excessive pumping of groundwater up from underground aquifers. There are two sets of yields: safe yield and sustainable yield. Safe yield is the amount of groundwater that can be withdrawn over a period of time without exceeding the long-term recharge rate or affecting the aquifer integrity. Sustainable yield is the amount of water extraction that can be sustained indefinitely without negative hydrological impacts, taking into account both recharge rate and surface water impacts. There are two types of aquifers: confined and unconfined. In confined aquifers, there is an overbearing layer called aquitard, which contains impermeable materials through whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precipitation
In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers. Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In Bangladesh
Irrigation (also referred to as watering) 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 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 is supplied to plants. Surface irrigation, also known as gravity irrigation, is the oldest form of irrigation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In Iran
Irrigation in Iran covers 89,930 km2 making it the fifth ranked country in terms of irrigated area. Tidal irrigation at Abadan island, Iran The Abadan Island (Fig. 1) in Khūzestān Province is situated between the Arvand and Bahmanshir rivers. The Arvand river (in Arabic: Shatt al-Arab) forms the boundary between Iran and Iraq and collects the waters from the Euphrates and Tigris rivers. On the island extensive orchards of date palm are found thriving on tidal irrigation in the desert climate, although many date palms were destroyed during the Iran–Iraq War. Palm tree belt The palm tree belt stretches along the Arvand River from Abadan south-east over a distance of about 40 km and is bounded in the interior by a road. The width of the belt varies from 2 to 6 km, and on average it is 4 km. The width is greater in the concave parts of the river bends and smaller in the convex parts. The convex parts have higher river levees and topography. The total area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In Pakistan
According to the United Nations' "UN World Water Development Report", the total actual renewable water resources increased from 2,961 m³ per capita in 2000. A more recent study indicates an available supply of water of little more than 1,000 m³ per person, which puts Pakistan in the category of a high stress country. Using data from the Pakistani federal government's Planning and Development Division, the overall water availability has decreased from 1,299 m³ per capita in 1996-97 to 1,101 m³ per capita in 2004-05. In view of growing population, urbanization and increased industrialization, the situation is likely to get worse. Nevertheless, excessive mining of groundwater goes on. Despite a lowering water table, the annual growth rate of electric tubewells has been indicated to 6.7% and for diesel tubewells to about 7.4%. In addition, increasing pollution and saltwater intrusion threaten the country's water resources. About 36% of the groundwater is classified as highly sali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In China
China primarily produces rice, wheat, potatoes, tomato, sorghum, peanuts, tea, millet, barley, cotton, oilseed, corn and soybeans. History The development of farming over the course of China's history has played a key role in supporting the growth of what is now the largest population in the world. Archaeology Analysis of stone tools by Professor Liu Li and others has shown that hunter-gatherers 23,000–19,500 years ago ground wild plants with the same tools that would later be used for millet and rice. Domesticated millet varieties ''Panicum miliaceum'' and ''Setaria italica'' may have originated in Northern China. Remains of domesticated millet have been found in northern China at Xinglonggou, Yuezhang, Dadiwan, Cishan, and several Peiligang sites. These sites cover a period over 7250-6050 BCE. The amount of domesticated millet eaten at these sites was proportionally quite low compared to other plants. At Xinglonggou, millet made up only 15% of all plant remains ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In The United States
Irrigation (also referred to as watering) 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 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 is supplied to plants. Surface irrigation, also known as gravity irrigation, is the oldest form of irrigation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In India
Irrigation in India includes a network of major and minor canals from Indian rivers, groundwater well based systems, tanks, and other rainwater harvesting projects for agricultural activities. Of these groundwater system is the largest. In 2013–14, only about 36.7% of total agricultural land in India was reliably irrigated, and remaining 2/3 cultivated land in India is dependent on monsoons. 65% of the irrigation in India is from groundwater. Currently about 51% of the agricultural area cultivating food grains is covered by irrigation. The rest of the area is dependent on rainfall which is most of the times unreliable and unpredictable. Indian government launched a demand side water management plan costing INR6000 crore or USD854 million across 8,350 water stressed villages of 78 districts in seven states – Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh – over five years from 2021–2022 to 2026–27, with the view to harvest rainwat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is about and one hectare contains about . In 1795, when the metric system was introduced, the ''are'' was defined as 100 square metres, or one square decametre, and the hectare ("hecto-" + "are") was thus 100 ''ares'' or km2 (10,000 square metres). When the metric system was further rationalised in 1960, resulting in the International System of Units (), the ''are'' was not included as a recognised unit. The hectare, however, remains as a non-SI unit accepted for use with the SI and whose use is "expected to continue indefinitely". Though the dekare/decare daa (1,000 m2) and are (100 m2) are not officially "accepted for use", they are still used in some contexts. Description The hectare (), although not a unit of SI, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, 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 revegetation, revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation 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 is supplied to plants. Surface irrigation, also known as gravity irri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Climate Change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane. Greenhouse gases absorb some of the heat that the Earth radiates after it warms from sunlight. Larger amounts of these gases trap more heat in Earth's lower atmosphere, causing global warming. Due to climate change, deserts are expanding, while heat waves and wildfires are becoming more common. Increased warming in the Arctic has contributed to melting permafrost, glacial retreat and sea ice loss. Higher temperatures are also causing m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater-related Subsidence
Groundwater-related subsidence is the subsidence (or the sinking) of land resulting from groundwater extraction. It is a growing problem in the developing world as cities increase in population and water use, without adequate pumping regulation and enforcement. One estimate has 80% of serious U.S. land subsidence problems associated with the excessive extraction of groundwater, making it a growing problem throughout the world. Groundwater can be considered one of the last free resources, as anyone who can afford to drill can usually draw up merely according to their ability to pump (depending on local regulations). However, as seen in the figure, pumping-induced Drawdown (hydrology), draw down causes a depression of the groundwater surface around the production well. This can ultimately affect a large region by making it more difficult and expensive to pump the deeper water. Thus, the extraction of groundwater becomes a tragedy of the commons, with resulting economic externalities. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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