Table 3.10 Grades for pollution prevention performance of vadose zone
Grade
Permeability of vadose zone rocks (soils)
Score
Strong
Thickness of single rock (soil) layer (Mb) ! 1.0 m, permeability
coefficient (K)
10
−7 cm/s, and continuous and stable distribution
1
Moderate
Thickness of single rock (soil) layer 0.5 m
Mb < 1.0 m,
permeability coefficient (K)
10
−7 cm/s, and continuous and stable
distribution.
Thickness of single rock (soil) layer (Mb) ! 1.0 m, permeability
coefficient of 10
−7 cm/s < K
10
−4 cm/s, and continuous and stable
distribution
Weak
The rock (soil) layer does not satisfy the above-mentioned conditions
for grades “strong” and ”moderate”
0
Table 3.11 Weights for vadose zone vulnerability assessment indicators
Groundwater
types
Characteristics
of overlying
vadose zone
Types of
vadose zone
Main factors and their weights
Pore water
Monolithologic
Monolithologic
Maximum pollution thickness(5),
permeability of rocks and soils(4),
adsorption of rocks and soils(3),
degradability of rocks and soils(2)
Bi-lithologic
Bi-lithologic
Maximum pollution thickness(5),
clay layer thickness(5), equivalent
permeability of clay layer(4),
permeability of sand layer(2), clay
adsorption(3), degradability of rocks
and soils(1)
Multi-lithologic
Multi-lithologic
Maximum pollution thickness(5),
cumulative thickness of clay layer
(5), equivalent permeability of clay
layer(4), equivalent permeability of
sand layer(2), clay adsorption(3),
degradability of rocks and soils(1)
Fissure water
Weathering
fissure
Bi-lithologic
Maximum pollution thickness(5),
permeability(4)
Tectonic fissure
Monolithologic
Maximum pollution thickness(5),
permeability(4)
Karst water
Bare karst
Monolithologic
Maximum pollution thickness(5),
permeability(4)
Covered karst
Bi-lithologic
Maximum pollution thickness(5),
permeability(4)
Karst-hole
Preferential
migration
passage
Pollution prevention of the vadose
zone not considered
3.2 Method of Groundwater Pollution Source Intensity Rating …
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