Groundwater - Groundwater overdraft. Groundwater is a highly useful and abundant resource, but in arid or semi-arid regions it cannot renew itself as rapidly as it is being withdrawn by humans. If groundwater is extracted intensively from water wells, as for irrigation or municipal use in arid or semi-arid regions, it may not recover to its pre-development state. The most evident problem that may result from this is a lowering of the water table beyond the reach of existing wells. Wells must consequently be deepe ...

See also:

Groundwater, Groundwater - Problems with groundwater, Groundwater - Groundwater overdraft, Groundwater - Subsidence, Groundwater - Seawater intrusion, Groundwater - Mining groundwater, Groundwater - Groundwater pollution

Read more here: » Groundwater: Encyclopedia II - Groundwater - Problems with groundwater

See also:

Groundwater flow equation, Groundwater flow equation - Mass Balance, Groundwater flow equation - Diffusion Equation Transient Flow, Groundwater flow equation - Rectangular Cartesian Coordinates, Groundwater flow equation - Circular Cylindrical Coordinates, Groundwater flow equation - Polar Coordinates, Groundwater flow equation - Assumptions, Groundwater flow equation - Laplace Equation Steady-State Flow

Read more here: » Groundwater flow equation: Encyclopedia II - Groundwater flow equation - Laplace Equation Steady-State Flow

Mass can be represented as density times volume, and under most conditions, water can be considered incompressible (density does not depend on pressure). The mass fluxes across the boundaries then become volume fluxes (as are found in Darcy's law). Using Taylor series to represent the in and out flux terms across the boundaries of the control volume, and using the divergence theorem to turn the flux across the boundary into a flux over the entire volume, the final form of ...

See also:

Groundwater flow equation, Groundwater flow equation - Mass Balance, Groundwater flow equation - Diffusion Equation Transient Flow, Groundwater flow equation - Rectangular Cartesian Coordinates, Groundwater flow equation - Circular Cylindrical Coordinates, Groundwater flow equation - Polar Coordinates, Groundwater flow equation - Assumptions, Groundwater flow equation - Laplace Equation Steady-State Flow

Read more here: » Groundwater flow equation: Encyclopedia II - Groundwater flow equation - Diffusion Equation Transient Flow

Most land areas on Earth have some form of aquifer underlying them, sometimes at significant depths. Fresh water aquifers, especially those with limited recharge by meteoric water, can be over-exploited and, depending on the local hydrogeology, may draw in non-potable water or saltwater (saltwater intrusion) from hydraulically connected aquifers or surface water bodies. This can be a serious problem especially in coasta ...

See also:

Aquifer, Aquifer - Aquifer classification, Aquifer - Saturated versus unsaturated, Aquifer - Aquifers versus aquitards, Aquifer - Confined versus unconfined, Aquifer - Human dependence on groundwater, Aquifer - Subsidence, Aquifer - Examples

Read more here: » Aquifer: Encyclopedia II - Aquifer - Human dependence on groundwater

To use the groundwater flow equation to estimate the distribution of hydraulic heads, or the direction and rate of groundwater flow, this partial differential equation (PDE) must be solved. The most common means of analytically solving the diffusion equation in the hydrogeology literature are: Laplace and Fourier transforms (to reduce the number of dimensions of the PDE), similarity transform (also called the Boltzmann transform) is commonly how the Theis solution is derived, separation of variables, which is m ...

See also:

Hydrogeology, Hydrogeology - Introduction, Hydrogeology - Hydrogeology in relation to other fields, Hydrogeology - Definitions and material properties, Hydrogeology - Hydraulic head, Hydrogeology - Porosity, Hydrogeology - Water content, Hydrogeology - Hydraulic conductivity, Hydrogeology - Specific storage and specific yield, Hydrogeology - Governing equations, Hydrogeology - Darcy's Law, Hydrogeology - Groundwater flow equation, Hydrogeology - Calculation of groundwater flow, Hydrogeology - Analytic methods, Hydrogeology - Numerical methods

Read more here: » Hydrogeology: Encyclopedia II - Hydrogeology - Calculation of groundwater flow

An aquifer is an underground layer of water-bearing permeable rock, or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. A common misconception is that groundwater exists in underground rivers (e.g. caves where water flows freely underground), while the truth is that the pore spaces of rocks in the subsurface are simply saturated with water — like a kitchen sponge, which can be pumped out and used for agricultural, industrial or municipal uses. The stud ...

Including:

Aquifer - Aquifer classification
Aquifer - Saturated versus unsaturated Aquifer - Aquifers versus aquitards Aquifer - Confined versus unconfined
Aquifer - Human dependence on groundwater Aquifer - Subsidence Aquifer - Examples

Read more here: » Aquifer: Encyclopedia - Aquifer

The Mahomet Aquifer supplies approximately 850,000 people with water. The Illinois Bureau of the Budget [1] projects that the population could increase to about 910,000 people by 2020. An estimated 100 million gallons a day (MGD) of groundwater is pumped from the aquifer to supply municipal, agricultural, commercial, industrial, and rural domestic users (Larson et al, 2003). Approximately 45% of the water withdrawn is consumed by the public, 29% by industry, and 18% by commercial users (Panno and Korab, 2000). The remaining percentage ...

See also:

Mahomet Aquifer, Mahomet Aquifer - Hydrogeologic setting, Mahomet Aquifer - Groundwater use, Mahomet Aquifer - Water quality, Mahomet Aquifer - Mahomet Aquifer Consortium

Read more here: » Mahomet Aquifer: Encyclopedia II - Mahomet Aquifer - Groundwater use

Attenuation is the decrease of the amount, force, magnitude, or value of something. For example, In biology, attenuation is a mechanism in the regulation of gene expression In ecology and geochemistry, attenuation is the ability to withhold contaminants in soil and groundwater by various mechanisms like adsorption, dilution, dispersion or biological degradation (biodegradation, bioremediation), causing a decrease in concentration and toxicity compared to the total amount of the contaminant. In envir

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The Berkeley Pit is a gigantic former open pit copper mine located in Butte, Montana, and is the largest Superfund site. It was opened in 1955 and operated by the Anaconda Mining Company and later by ARCO the Atlantic Richfield Company, until its closure in 1982. When the pit was closed, the water pumps at the bottom were also turned off, which caused groundwater from the surrounding basin to leak into the pit. The water seeped through metal deposits, causing it to become heavily acidic and laden with heavy metals and dangerous chemic ...

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Water content is a ratio used in hydrogeology and soil mechanics to indicate the amount of water a porous medium contains. In fully saturated groundwater aquifers, all the available pore spaces are filled with water (volumetric water content = porosity). Above the capillary fringe, some of the pore spaces have air in them too. When the porous medium in question is soil, water content is synonymous with soil moisture. Water content can either be the volumetric (by volume) or gravimetric (by weight) fraction of the total rock whi ...

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A water well is an artificial excavation or structure put down by any method such as digging, boring or drilling for the purposes of withdrawing water from underground aquifers. Water well - Types of water wells. Until recent centuries, all artificial wells were pumpless dug wells of varying degrees of formality. Their indispensibility has produced numerous literary references, literal and figurative, to them, including the Christian Bible story of Jesus meeting a woman at Jacob's well (John 4:6) and the "D ...

Including:

Water well - Types of water wells
Water well - Aquifer classification Water well - Use classification
Water well - Drawing Water Water well - Possible contamination Water well - History Water well - Cultural References

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The water table is the upper limit of abundant groundwater. In the vadose zone, above the water table, the interstices between particles of earth are filled by air, or by air and water (with the exception of the capillary fringe). Below it, every available space is saturated with water. A large amount of water within a body of sand or rock below the water table is called an aquifer. A so-called "perched aquifer" (or perched water table) occurs when the descent of water percolating fro ...

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Escherichia coli (usually abbreviated to E. coli) is one of the main species of bacteria that live in the lower intestines of warm-blooded animals (including birds and mammals) and are necessary for the proper digestion of food. Its presence in groundwater is a common indicator of fecal contamination. ("Enteric" is the adjective that describes organisms that live in the intestines. "Fecal" is the adjective for organisms that live in feces, so it is often a synonym for "enteric.") The name comes from its discoverer, Theodor Escherich. It belongs among the Enterobacteriaceae, and is com ...

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Water resources are sources of water that are useful or potentially useful to humans. It is important because it is needed for life to exist. Many uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water. Only 3% of water on the Earth is fresh water, and over two thirds of this is frozen in glaciers and polar ice caps. Water demand already exceeds supply in many parts of the world, and many more areas are expected to experience this imba ...

Including:

Water resources - Water and conflict Water resources - Sources of fresh water
Water resources - Surface water Water resources - Sub-surface water Water resources - Desalination Water resources - Frozen water
Water resources - Threats to fresh water
Water resources - Climate change Water resources - Depletion of aquifiers Water resources - Pollution and water protection
Water resources - Uses of fresh water
Water resources - Agricultural Water resources - Industrial Water resources - Household Water resources - Recreation Water resources - Environmental
Water resources - World water supply and distribution

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Any aquifer, and here specifically the High Plains Aquifer, is a storage reservoir in the water cycle. The USGS has performed several studies of the aquifer, to determine what is coming in (groundwater recharge from the surface), what is leaving (pumping and baseflow to streams) and what the net changes in storage are (have water levels risen, fallen or stayed the same — see figure above). Simply put, water in, less the water out, is equal to the change in water stored in the aquifer. This type of mass-balance "accounting" is how hydrologic budgets are performed, and is a crucial fir ...

See also:

Ogallala Aquifer, Ogallala Aquifer - General characteristics, Ogallala Aquifer - Aquifer water balance, Ogallala Aquifer - Groundwater recharge, Ogallala Aquifer - Groundwater discharge, Ogallala Aquifer - Change in groundwater storage

Read more here: » Ogallala Aquifer: Encyclopedia II - Ogallala Aquifer - Aquifer water balance

Water fluoridation controversy refers to the debate surrounding the health benefits of governments fluoridating water supplies. Water fluoridation controversy - Overview. Fluoride is a naturally-occurring mineral found in all water sources (lakes, rivers, groundwater and oceans). Community water fluoridation is the process of adding industrial fluoride to drinking water supplies to a level claimed to be optimal for oral health. Advocates of water fluoridation claim that this is similar to fortifying ...

Including:

Water fluoridation controversy - Overview
Water fluoridation controversy - Benefits Water fluoridation controversy - Risks Water fluoridation controversy - Politics
Water fluoridation controversy - Controversy
Water fluoridation controversy - Scientific Debate Water fluoridation controversy - Court cases Water fluoridation controversy - Medical approval
Water fluoridation controversy - Implementation
Water fluoridation controversy - USA Water fluoridation controversy - Canada Water fluoridation controversy - Rest of world
Water fluoridation controversy - Notes

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The deposition of the aquifer material dates back to late Miocene to early Pliocene age when the Rocky Mountains were being uplifted. As the land to the west rose, rivers and streams cut channels in a generally west to east or southeast direction. Erosion of the Rockies provided alluvial and eolian sediment that filled the ancient channels and eventually covered the entire area of the present-day aquifer, forming the water-bearing Ogallala Formation. The depth of the formation varies with the shape of the pre-Ogallala surface, being deepest ...

See also:

Ogallala Aquifer, Ogallala Aquifer - General characteristics, Ogallala Aquifer - Aquifer water balance, Ogallala Aquifer - Groundwater recharge, Ogallala Aquifer - Groundwater discharge, Ogallala Aquifer - Change in groundwater storage

Read more here: » Ogallala Aquifer: Encyclopedia II - Ogallala Aquifer - General characteristics

This diagram indicates typical flow directions in a cross-sectional view of a simple confined/unconfined aquifer system (two aquifers with one aquitard between them, surrounded by aquiclude) which is in contact with a stream (typical in humid regions). The water table and unsaturated zone are also illustrated. Aquifer - Saturated versus unsaturated. Groundwater can be found at nearly every point in the earth's shallow subsurface, to some degree; although aquifers do not necessarily contain fresh water. The ...

See also:

Aquifer, Aquifer - Aquifer classification, Aquifer - Saturated versus unsaturated, Aquifer - Aquifers versus aquitards, Aquifer - Confined versus unconfined, Aquifer - Human dependence on groundwater, Aquifer - Subsidence, Aquifer - Examples

Read more here: » Aquifer: Encyclopedia II - Aquifer - Aquifer classification

The Mahomet Aquifer consists of sand and gravel deposited by glacial meltwater flowing westward along the Mahomet Bedrock Valley during the pre-Illinois glacial episode. This bedrock valley forms the western part of the Teays-Mahomet Bedrock Valley System that extends into Illinois from Indiana (Larson et al, 2003). Most of the sand and gravel of the Mahomet Aquifer is from the lower half of the Banner Formation and belongs to the Mahomet Sand Member which is buri ...

See also:

Mahomet Aquifer, Mahomet Aquifer - Hydrogeologic setting, Mahomet Aquifer - Groundwater use, Mahomet Aquifer - Water quality, Mahomet Aquifer - Mahomet Aquifer Consortium

Read more here: » Mahomet Aquifer: Encyclopedia II - Mahomet Aquifer - Hydrogeologic setting

The change in level of a lake is controlled by the difference between the sources of inflow and outflow, compared to the total volume of the lake. The significant input sources are precipitation onto the lake; runoff carried by streams and channels from the lake's catchment area; groundwater channels and aquifers, and man-made sources from outside the catchment area. Output sources are evaporation from the lake; surface and groundwater flows, and any extraction of lake water by humans. As climate conditions and human water requirements vary, these wil ...

See also:

Lake, Lake - Origin of natural lakes, Lake - Characteristics, Lake - Types of lakes, Lake - Artificial lakes, Lake - Abiotic and biotic limnology, Lake - How lakes disappear, Lake - Extraterrestrial lakes, Lake - Notable lakes

Read more here: » Lake: Encyclopedia II - Lake - Characteristics