Where Does Groundwater Go?
Water does not stay underground forever, it eventually returns to the surface. Some ways this can happen are:
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Where the water table is shallow enough trees can tap groundwater. Most of the water is evaporated by the leaves. |
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In the dry season many rivers, swamps, and wetlands, particularly in northern areas, rely heavily on ground water discharge as a source of water. |
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Springs are natural outlets for ground water, either simple overflow as shown in example on the left or escape along a fault as in the right hand example. |
Much like the flow of water in a river, groundwater is subject to gravity and is almost always in motion, flowing from high areas to lower areas.
The rate of flow is very slow compared to the flow of water on the surface. It is typically in the range of several millimetres per year to several metres per year.
The time that passes between rainwater entering an aquifer and discharging back to the surface varies between tens of years to tens of thousands of years.
In the higher rainfall areas in the north, tens to hundreds of years is typical. In the arid areas of the south, thousands to tens of thousands of years is typical.
