Water is the world's most important resource, without it life on Earth would not exist. We rely on it for everything from drinking supplies, to its use in agriculture, to supporting animal and plant life around the world. Approximately 71% of the Earth's surface is covered by water but not all of it is available to us for use.
Over 96% of the world water is held in our oceans and only 2.5% of Earth's water is freshwater. Of this 2.5% of freshwater the majority is trapped in glaciers and ice-caps with the remainder being groundwater or surface water such as lakes and rivers.
In Ireland we rely heavily on groundwater, it supplies 20-25% of our drinking water supplies and in some counties it supplies up to 50%. In rural areas not served by water schemes it is the only source of drinking water with these areas relying on wells and springs.
The Water Cycle
The Earth's water is always moving and changing state from liquid to vapour to ice and back again. This process is known as the water cycle or the hydrologic cycle, it has been working for billions of years and all life on Earth depends on it. The water cycle shows the circulation of water from Earth's oceans to the atmosphere to the land and back again.
Water from the oceans and the land is evaporated by the sun, as it rises it cools and condenses forming clouds, when the clouds get too dense they drop this water as rain. As the rain falls it can either run off the land and return to the ocean or it can soak into the ground and be stored in underground reservoirs known as aquifers.