Water
Water
RESOURCES
RESOURCES
DISTRIBUTION OF WATER ON EARTH
WHERE AND IN WHAT FORMS IS WATER AVAILABLE ON EARTH?
Earth's water exists naturally in different forms and locations:
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1. Air
2. Surface
3.Below the ground (Underground); and
4. Oceans
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It is distributed through WATER CYCLE
HOW DOES WATER MOVE FROM THE ATMOSPHERE TO THE GROUND AND BACK?
PRECIPITATION:
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This is an important form of available freshwater
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About 40% of precipitation has previously evaporated from the oceans; the rest from the land.
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Varies greatly around the world.
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EVAPORATION:
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1/3 of the precipitation returns to the atmosphere.
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The drier the climate, the higher the proportion if precipitation returns to the atmosphere.
HOW MUCH FRESHWATER IS FOUND AT THE EARTH'S SURFACE?
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About 68.7% of the world's freshwater is frozen in ice sheets and glaciers.
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Most remains inaccessible in the Arctic, Antarctica, or Greenland
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The land-based glaciers and permanent snow and ice supply water in many countries.
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SURFACE WATER - ABOUT 0.3%
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- Lakes, ponds, rivers, streams, and wetlands.
- Represent about 80% of the renewable surface water and groundwater that is available in a given year.
- River basins are a useful "natural unit" for the management of water resources.