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:
1. Air
2. Surface
3.Below the ground (Underground); and
4. Oceans
It is distributed through WATER CYCLE
HOW DOES WATER MOVE FROM THE ATMOSPHERE TO THE GROUND AND BACK?
PRECIPITATION:
This is an important form of available freshwater
About 40% of precipitation has previously evaporated from the oceans; the rest from the land.
Varies greatly around the world.
EVAPORATION:
1/3 of the precipitation returns to the atmosphere.
The drier the climate, the higher the proportion if precipitation returns to the atmosphere.
HOW MUCH FRESHWATER IS FOUND AT THE EARTH'S SURFACE?
About 68.7% of the world's freshwater is frozen in ice sheets and glaciers.
Most remains inaccessible in the Arctic, Antarctica, or Greenland
The land-based glaciers and permanent snow and ice supply water in many countries.
SURFACE WATER - ABOUT 0.3%
- 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.