Table 4.3
Model for assessment of inherent groundwater vulnerability
Model
Parameters
Description
Application
GOD
Groundwater type (G), overburden layer
(O), depth to water table (D)
The mitigation index D
i = G*O* D, but in the case of
confined aquifer, O is ignored, that is, D
i = G*D. The
parameter value ranges from 0 to 1
Unconfined water and
confined water in porous
media (empirical method)
Legrand
Depth to water table (D), vadose zone media
(S), hydraulic conductivity (C), hydraulic
gradient (G), horizontal distance of solid
waste discharge site (H)
D
i = D + S + C + G + H. A higher D
i value implies better
mitigation performance, and vice versa
Lots that may be affected
by solid waste discharge
sites
EPIK
Epikarst (E), protective cover
(P), infiltration conditions (I), karst network
development (K)
D
i =
aE +
bP +
cI +
dK, wherein
a, b, c, d are parameter
weights. A higher D
i value implies better mitigation
performance and less vulnerability of the aquifer to
contamination
Karst water
OCP
Overburden layer (O), current
(C), precipitation (P), karst water network
development (K)
The results are obtained by coupling various parameters.
The coupling method is determined according to the
hydrogeological characteristics of assessed area, which can
make the sum or product. O, C, and P are selected
when assessing the mitigation performance of resources, and
O, C, P and K when assessing the performance in protection
of water sources
Karst water
LEA
Overburden factor (O), current (C)
It follows the concept of the PI method, but it is simplified
with no numerical indicators. It produces qualitative and
relative classification results, and more applies to resource
vulnerability assessment
Areas with small data
volumes
DRASTIC
Depth to water table (D), net recharge of the
aquifer (R), aquifer media (A),soil media
(S), topography (T), impact of vadose zone
media (I), hydraulic conductivity of the
aquifer (C)
V
i = D
w D
r + R
w R
r + A
w A
r + S
w S
r + T
w T
r + I
w I
r + C
w C
r .
A larger V
i values indicates more vulnerability to
contamination
Unconfined water and
confined water in porous
media
(continued)
82
4 Risk Assessment of Groundwater Contamination Sites
Model for assessment of inherent groundwater vulnerability
Model
Parameters
Description
Application
GOD
Groundwater type (G), overburden layer
(O), depth to water table (D)
The mitigation index D
i = G*O* D, but in the case of
confined aquifer, O is ignored, that is, D
i = G*D. The
parameter value ranges from 0 to 1
Unconfined water and
confined water in porous
media (empirical method)
Legrand
Depth to water table (D), vadose zone media
(S), hydraulic conductivity (C), hydraulic
gradient (G), horizontal distance of solid
waste discharge site (H)
D
i = D + S + C + G + H. A higher D
i value implies better
mitigation performance, and vice versa
Lots that may be affected
by solid waste discharge
sites
EPIK
Epikarst (E), protective cover
(P), infiltration conditions (I), karst network
development (K)
D
i =
aE +
bP +
cI +
dK, wherein
a, b, c, d are parameter
weights. A higher D
i value implies better mitigation
performance and less vulnerability of the aquifer to
contamination
Karst water
OCP
Overburden layer (O), current
(C), precipitation (P), karst water network
development (K)
The results are obtained by coupling various parameters.
The coupling method is determined according to the
hydrogeological characteristics of assessed area, which can
make the sum or product. O, C, and P are selected
when assessing the mitigation performance of resources, and
O, C, P and K when assessing the performance in protection
of water sources
Karst water
LEA
Overburden factor (O), current (C)
It follows the concept of the PI method, but it is simplified
with no numerical indicators. It produces qualitative and
relative classification results, and more applies to resource
vulnerability assessment
Areas with small data
volumes
DRASTIC
Depth to water table (D), net recharge of the
aquifer (R), aquifer media (A),soil media
(S), topography (T), impact of vadose zone
media (I), hydraulic conductivity of the
aquifer (C)
V
i = D
w D
r + R
w R
r + A
w A
r + S
w S
r + T
w T
r + I
w I
r + C
w C
r .
A larger V
i values indicates more vulnerability to
contamination
Unconfined water and
confined water in porous
media
(continued)
82
4 Risk Assessment of Groundwater Contamination Sites