Water Cycles - Hydrogeology: Objectives, Methods, Applications - page 20

Table 1 Estimated Global Distribution of Water on Earth.

Volume of water stored
Total Freshwater

in 10 3 km 3 in 10 3 km 3 in % of total freshwater

OCEANS
and salty ice fl oes 1,350,000

SALTY LAKES 100

ICE:
icecaps, glaciers, snow,
permafrost

23,000 23,000 60

WATER BELOW GROUND

Aquifers
0-800 m below ground 8,000 16,000 39

> 800 m below ground 8,000

Soil moisture 16 16

CONTINENTAL SURFACE WATER
Lakes

176 176

Riverbeds 2 2

1

ATMOSPHERE 13 13

BIOLOGICAL WATER 1 1

HYDROSPHERE 1,390,000 40,200 100

GLOBAL (0.3 % of the
mantle)

2,000,000

According to the BRGM, there are around 200 exploitable regional aquifers in France,
ranging from 100 to 100,000 km 2 , and containing some 2,000 km 3 of water. It is estimated
that 100 km 3 per year fl ow out to springs and rivers, and that 7 km 3 per year are drawn from
these aquifers.

Figure 6 Solar radiation.