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Aquifer
An aquifer is an underground layer of water-bearing material, consisting of permeability (Earth sciences), permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The study of water flow in aquifers and the characterization of aquifers is called ''hydrogeology''. Related concepts include aquitard, a bed (geology), bed of low permeability along an aquifer, and aquiclude (or ''aquifuge''), a solid and impermeable region underlying or overlying an aquifer, the pressure of which could lead to the formation of a confined aquifer. Aquifers can be classified as saturated versus unsaturated; aquifers versus aquitards; confined versus unconfined; isotropic versus anisotropic; porous, karst, or fractured; and transboundary aquifer. Groundwater from aquifers can be sustainably harvested by humans through the use of qanats leading to a well. This groundwater is a major source of fresh water for many regions, althoug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquifer En
An aquifer is an underground layer of water-bearing material, consisting of permeable or fractured rock, or of unconsolidated materials (gravel, sand, or silt). Aquifers vary greatly in their characteristics. The study of water flow in aquifers and the characterization of aquifers is called ''hydrogeology''. Related concepts include aquitard, a bed of low permeability along an aquifer, and aquiclude (or ''aquifuge''), a solid and impermeable region underlying or overlying an aquifer, the pressure of which could lead to the formation of a confined aquifer. Aquifers can be classified as saturated versus unsaturated; aquifers versus aquitards; confined versus unconfined; isotropic versus anisotropic; porous, karst, or fractured; and transboundary aquifer. Groundwater from aquifers can be sustainably harvested by humans through the use of qanats leading to a well. This groundwater is a major source of fresh water for many regions, although it can present various challenges, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water 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 Groundwater recharge, recharged from the surface; it may discharge from the surface naturally at spring (hydrosphere), springs and Seep (hydrology), seeps, and can form oasis, oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction water well, wells. The study of the distribution and movement of groundwater is ''hydrogeology'', also called groundwater hydrology. Typically, groundwater is thought o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogeology
Hydrogeology (''hydro-'' meaning water, and ''-geology'' meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rock (geology), rocks of the Earth's crust (geology), crust (commonly in aquifers). The terms groundwater hydrology, geohydrology, and hydrogeology are often used interchangeably, though hydrogeology is the most commonly used. Hydrogeology is the study of the laws governing the movement of subterranean water, the mechanical, chemical, and thermal interaction of this water with the porous solid, and the transport of energy, chemical constituents, and particulate matter by flow (Domenico and Schwartz, 1998). Groundwater engineering, another name for hydrogeology, is a branch of engineering which is concerned with groundwater movement and design of Well, wells, Pump, pumps, and drains. The main concerns in groundwater engineering include groundwater contamination, conservation of suppli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Pollution
Groundwater pollution (also called groundwater contamination) occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution (or contamination) can also occur from naturally occurring contaminants, such as arsenic contamination of groundwater, arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease (Waterborne diseases, water-borne diseases). The pollutant often produces a contaminant Plume (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overdrafting
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. The primary cause of groundwater depletion is the excessive pumping of groundwater up from underground aquifers. Insufficient recharge can lead to depletion, reducing the usefulness of the aquifer for humans. Depletion can also have impacts on the environment around the aquifer, such as soil compression and land subsidence, local climatic change, soil chemistry changes, and other deterioration of the local environment. 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 recha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saltwater Intrusion
Saltwater intrusion is the movement of saline water into freshwater aquifers, which can lead to groundwater quality degradation, including drinking water sources, and other consequences. Saltwater intrusion can naturally occur in coastal aquifers, owing to the hydraulic connection between groundwater and seawater. Because saline water has a higher mineral content than freshwater, it is denser and has a higher water pressure. As a result, saltwater can push inland beneath the freshwater. In other topologies, submarine groundwater discharge can push fresh water into saltwater. Certain human activities, especially groundwater pumping from coastal freshwater wells, have increased saltwater intrusion in many coastal areas. Water extraction drops the level of fresh groundwater, reducing its water pressure and allowing saltwater to flow further inland. Other contributors to saltwater intrusion include navigation channels or agricultural and drainage channels, which provide conduits for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Table
The water table is the upper surface of the phreatic zone or zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with groundwater, which may be fresh, saline, or brackish, depending on the locality. It can also be simply explained as the depth below which the ground is saturated. The portion above the water table is the vadose zone. It may be visualized as the "surface" of the subsurface materials that are saturated with groundwater in a given vicinity. In coarse soils, the water table settles at the surface where the water Hydraulic head, pressure head is equal to the atmospheric pressure (where gauge pressure = 0). In soils where capillary action is strong, the water table is pulled upward, forming a capillary fringe. The groundwater may be from precipitation or from more distant groundwater flowing into the aquifer. In areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overexploitation
Overexploitation, also called overharvesting or ecological overshoot, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term applies to natural resources such as water aquifers, grazing pastures and forests, wild medicinal plants, fish stocks and other wildlife. In ecology, overexploitation describes one of the five main activities threatening global biodiversity. Ecologists use the term to describe populations that are harvested at an unsustainable rate, given their natural rates of mortality and capacities for reproduction. This can result in extinction at the population level and even extinction of whole species. In conservation biology, the term is usually used in the context of human economic activity that involves the taking of biological resources, or organisms, in larger numbers than their populations can withstand. The term i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Qanats
A qanāt () or kārīz () is a water supply system that was developed in ancient Iran for the purpose of transporting usable water to the surface from an aquifer or a well through an underground aqueduct. Originating approximately 3,000 years ago, its function is essentially the same across the Middle East and North Africa, but it is known by a variety of regional names beyond today's Iran, including: kārēz in Afghanistan and Pakistan; foggāra in Algeria; khettāra in Morocco; falaj in Oman and the United Arab Emirates; and ʿuyūn in Saudi Arabia. In addition to those in Iran, the largest extant and functional qanats are located in Afghanistan, Algeria, China (i.e., the Turpan water system), Oman, and Pakistan. Proving crucial to water supply in areas with hot and dry climates, a qanat enables water to be transported over long distances by largely eliminating the risk of much of it evaporating on the journey. The system also has the advantage of being fairly resistant to Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food energy or organic micronutrients. Its chemical formula, , indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. In liquid form, is also called "water" at standard temperature and pressure. Because Earth's environment is relatively close to water's triple point, water exists on Earth as a solid, a liquid, and a gas. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permeability (Earth Sciences)
In fluid mechanics, materials science and Earth sciences, the permeability of porous media (often, a rock or soil) is a measure of the ability for fluids (gas or liquid) to flow through the media; it is commonly symbolized as ''k''. Fluids can more easily flow through a material with high permeability than one with low permeability. The permeability of a medium is related to the '' porosity'', but also to the shapes of the pores in the medium and their level of connectedness. Fluid flows can also be influenced in different lithological settings by brittle deformation of rocks in fault zones; the mechanisms by which this occurs are the subject of fault zone hydrogeology. Permeability is also affected by the pressure inside a material. The SI unit for permeability is the square metre (m2). A practical unit for permeability is the '' darcy'' (d), or more commonly the ''millidarcy'' (md) The name honors the French Engineer Henry Darcy who first described the flow of wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
