Water Sources
Water covers 71% of the Earth's surface; about 97% of which exist in the ocean as saltwater. The remaining 3% represents the amount of freshwater on the planet. Unfortunately, however, 90% of this freshwater is inaccessible for human use because it is trapped in glaciers and ice caps.
Groundwater and fresh water are useful or potentially useful to humans as water resources. Ultimately though, only 0.014% of the earth's total volume of water is easily available to us for agricultural, industrial, and domestic purposes. This water exists in a variety of forms, including soil moisture, groundwater, water vapor, and lakes and streams.
The collective mass of water found on, under, and over the surface of a planet is called hydrosphere.
| Water Source | Water volume (cubic miles) |
Percent of total water |
|---|---|---|
| Oceans | 317,000,000 | 97.24% |
| Glaciers & icecaps | 7,000,000 | 2.14% |
| Groundwater | 2,000,000 | 0.61% |
| Fresh-water lakes | 30,000 | 0.009% |
| Inland seas | 25,000 | 0.008% |
| Soil moisture | 16,000 | 0.005% |
| Atmosphere | 3,100 | 0.001% |
| Rivers | 300 | 0.0001% |
| Total water volume | 326,000,000 | 100% |
(Source: USA National Weather Service)
