Water, air and sunlight consist of the three basic elements for plants and animals life. simply put, water make the existence of the human race on the earth. With few exceptions, it almost has been a natural resource that people take for granted. Now, the global water resource situation has changed, many areas face to water crisis. It reports that there are 80 countries have water shortages and 2 billion people lack access to clean water.
Approximately 70% of the Earth’s surface is covered water, the remaining 30% of the land surface of the earth, but also present water. Total water volume is 138.6 × 108 m3 , including 3.5 × 108 m3 fresh water, about 2.53% of total reserves. On other hand, due to the development of technical and economic limited, up to now, sea water, deep ground water and ice water has rarely been directly used. The most closely human life and production are lakes, rivers and shallow groundwater, it about 104.6 × 104 m3, only 0.34% of total water reserves lower than one millionth.
Global Water Reserves Of Different Water Types
|Water Type||Distribution area||Water Reserves||Accounting of total water||Accounting of total fresh water|
|Glaciers and snow-capped mountains||1622.75||24064.1||1.74||68.7|
|Soil bottom ice||2100||300.00||0.222||0.86|
|Fresh lake water||123.64||91.00||0.007|