Groundwater has been used for domestic and irrigation needs from time immemorial. It is a component of the hydrological cycle, vital for human sustenance. Unlike surface water, groundwater cannot be readily observed. Consequently, it was long considered to be mysterious or even occult in nature, influencing legal decisions relating to groundwater ownership and use.
Its annual renewability from precipitation is limited, and its chemical quality is vulnerable to degradation by human action. In many parts of the world, groundwater extraction is known to greatly exceed its renewability. Consequently, its rational management to benefit present and future generations is a matter of deep concern for many nations.
Historically, large scale extraction neccessitated formation of laws to regulate groundwater usage and ownership.The collective contributions of Arago, Darcy and Dupuit, embellished by the observations of Chamberlain and Darton, have inspired the modern conceptual framework for an integrated understanding of three-dimensional groundwater flow patterns in groundwater basins, driven by precipitation recharge, gravity, and by evapotranspiration discharge.
Groundwater exploration, drilling methods, well construction techniques and the mathematical theory of aquifer hydraulics was the focus of groundwater study till 1950s. But later it became a part of the environmental movement as its pollution aspects were highlighted. Saltwater ingress, depletion due to overextraction, pollution through toxic chemicals and effects on wildlife are some of the main issues.
Global warming has direct implications on groundwater through the hydrological cycle. Changing patterns of precipitation and evapotranspiration changing groundwater depletion-recharge and saltwater intrustion in coastal basins due to rising sea levels are some of them. Groundwater management is a challenging venture, requiring an integration of scientific knowledge with communal will to adapt to constraints of a finite common resource.
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