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
Sea water 3613 1338000 96.5
Ground water 13480 23400 1.7 30.1
fresh groundwater 12870 0.94
Soil water 8200 16.5 0.001 0.05
Glaciers and snow-capped mountains 1622.75 24064.1 1.74 68.7
Soil bottom ice 2100 300.00 0.222 0.86
Lake water 206.87 176.40 0.013 0.26
Fresh lake water 123.64 91.00 0.007
Swamp water 268.26 11.47 0.0008 0.03
River water 14880 2.12 0.0002 0.006
Biological water 51000 1.12 0.0001 0.003
Atmospheric Water 51000 12.90 0.001 0.001