Water Sources

Water Sources

Hydrologic Cycle
Hydrologic cycle (source: Bogardi et al., 2012, Water security for planet under pressure)

Of all of the water that is on the planet, an estimated 0.77% is available as freshwater.  More than 98% of the water is in the ocean and polar ice caps/glaciers, making freshwater relatively scarce.

With an estimated 10.8 million cubic kilometers of freshwater available, conservation and management of this precious resource is becoming a key policy issue for governments throughout the world.

It is estimated that there is 12,700 to 12,900 cubic kilometers of renewable freshwater available in the atmosphere, and hence, there is a great opportunity to harvest this renewable resource to address water stress and strain.

Estimation of Global Water Distribution (percentages are rounded up, so will not add to 100)

Water Source

Water Volume in Cubic Kilometers

Percent of Freshwater

Percent of Total Water

Oceans, Seas, & Bays

1,338,000,000

--

96.54

Ice caps, Glaciers, & Permanent Snow

24,064,000

68.7

1.74

Groundwater

23,400,000

--

1.69

Fresh

10,530,000

30.1

0.76

Saline

12,870,000

--

0.93

Soil Moisture

16,500

0.05

0.001

Ground Ice & Permafrost

300,000

0.86

0.022

Lakes

176,400

--

0.013

Fresh

91,000

0.26

0.007

Saline

85,400

--

0.006

Atmosphere

12,900

0.04

0.001

Swamp Water

11,470

0.03

0.0008

Rivers

2,120

0.006

0.0002

Biological Water

1,120

0.003

0.0001

Source: Igor Shiklomanov's chapter "World fresh water resources" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh, as cited by US Geological Service