Environmental Engineering Reference
In-Depth Information
Figure 26.15
The consumption of water in some
Mediterranean countries.
Table 26.2 Principal Mediterranean aquifers
Permeability (m day
−1
)
Type
Porosity (%)
Shallow alluvium
30-40
10-1000
Sandstone
10-30
0·1-10
Limestone
5-30
0·1-50
Karstic limestone
5-25
100-10000
Basalt
2-15
0·1-1000
Fresh igneous/metamorphic
2
0·000001
Weathered igneous/ metamorphic
10-20
0·1-2
In sub-humid Mediterranean environments, however, the hydrological cycle is less
continuous. Higher rates of surface evaporation mean that smaller amounts of water are
available for underground storage. As illustrated in Figure 26.16a, low rainfall is subject
to loss by high rates of evaporation and evapotranspiration. The remainder runs off the
surface, evaporates at the surface or infiltrates locally. There is some groundwater flow,
and in coastal
