Water can be found everywhere on earth, as most of the earth consists of water; namely the oceans. On land water cannot only be found in taps and toilets, but also outside the house in streams, lakes, wetlands and reservoirs. This is called surface water.
What we cannot see with our own eyes is that water can also be found in the ground, this is called groundwater. Groundwater is rainwater that infiltrates into the soil and is stored in pores. The soil consists of different layers, the so-called aquifers, that all contain certain amounts of water. The layer that consists mainly of groundwater is called the saturation layer. When rain falls the saturation layer will grow wider as a result of an expanding amount of groundwater.
Finally water can be found in gaseous state in the sky as moist or in cloud form.
| The freshwater we use from the surface first arrives as a result of rainfall, known as precipitation. Part of the precipitation falls on land and infiltrates into the ground. Another part of the precipitation evaporates and thereby returns to the atmosphere, to fall down again when it is raining. The last part of the precipitation is called surface run-off. Surface run-off flows directly into streams, lakes, wetlands and reservoirs. |
The precipitation that infiltrates into the ground moves downwards through pores, which are small voids in the soil. The precipitation moves towards a zone that consists merely of water, and then becomes groundwater. Groundwater slowly moves towards surface water in streams and lakes. Eventually all the precipitation will end up in surface waters at some point. Then the top layer of the water evaporates and rises up into the sky to form clouds. When the pressure builds due to increasing amounts of water, the clouds move inland and it starts to rain. The whole cycle as described here starts over again and will go on and on.
Click here for a schematic representation of the water cycle
The ground is made up of different types of layers vertically, called the aquifers. Groundwater spreads through the ground horizontally; it moves from the area of infiltration through an aquifer and out to a discharge area, as a part of the water cycle. This can be a well, a lake, a stream or even an ocean. Groundwater normally moves from points of high elevation and pressure to points of lower elevation and pressure. This movement is quite slow, typically only 1 meter or so per year and rarely more than 0.3 meter per day.
For water terminology check out our Water Glossary or go back to water FAQ overview
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