Explain about ' Groundwater' .

Groundwater (or ground water) is water present beneath the Earth's surface in soil pore spaces and in the fractures of rock formations. 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, And eventually flows to, the surface naturally; Often OCCURS discharge naturally at springs and seeps, and can form oases or wetlands. Also Often groundwater is withdrawn for agricultural, municipal, and industry use by constructing and operating extraction wells.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 flowing-through shallow water aquifers, but, in the technical sense, it can Also Contain soil moisture, permafrost (frozen soil), immobile water in very low permeability bedrock, and deep geothermal water or oil formation. Groundwater is hypothesized to Provide lubrication That can possibly influence the movement of faults. It is likely That much of Earth's subsurface contains some water, Which May be mixed With other fluids in some instances. Groundwater May not be confined only to Earth. The formation of some of the landforms Observed on Mars May Have Been Influenced by groundwater. Also there is evidence That May Also liquid water exist in the subsurface of Jupiter's moon Europa.

Often groundwater is cheaper, more convenient and vulnerable to pollution than surface water less. THEREFORE, it is Commonly used for public water supplies. For example, groundwater Provides the largest source of usable water storage in the United States and California Withdrawals Annually the largest amount of groundwater of all the states. Underground water reservoirs Contain far more than the capacity of all surface reservoirs and lakes in the US, Including the Great Lakes. Many local water supplies are derived from Solely groundwater.

Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers and lakes. MOST Often groundwater pollution results from improper disposal of wastes on land. Major sources include industry and household chemicals and garbage landfills, excessive fertilizers and pesticides used in agriculture and industrial waste lagoons, tailings and process wastewater from mines, oil field brine pits, leaking underground oil storage tanks and pipelines, sewage sludge and septic systems.