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The ground b elow our feet acts as a vast store of water, nearly 30% of all freshwater resources on earth are found underground . This ‘groundwater ’ exists in the pores between grains of rock or soil, within fractures in the rock , or even in large cave systems . Groundwater originates as rainfall or snowmelt that soaks into the ground continuing downwards , under the influence of gravity , until it reaches a zone in which all the available spaces are saturated with water – the top of this zone is called the water table. The level of the water tab le varies across different terrains, climates and rock types, and over time. Rocks that store and transmit important quantities of ground water and provide critical resources are called aquifers. |
