Geography Reference
In-Depth Information
Table 5. Description of DRASTIC and Pesticide DRASTIC parameters
Parameter
Description
Relative Weight
DRASTIC
DRASTIC-P
Represents the depth from the
ground surface to the water table,
deeper water table levels imply
lesser chance for contamination
to occur.
Depth to
Water
5
5
Represents the amount of water
which penetrates the ground
surface and reaches the water
table, recharge water represents
the vehicle for transporting
pollutants.
Net Recharge
4
4
Refers to the saturated zone
material properties, which
controls the pollutant attenuation
processes.
Aquifer
Media
3
3
Represents the uppermost
weathered portion of the
unsaturated zone and controls the
amount of recharge that can
infiltrate downward.
Soil Media
2
5
Refers to the slope of the land
surface, it dictates whether the
runoff will remain on the surface
to allow contaminant percolation
to the saturated zone.
Topography
1
3
Is defined as the unsaturated zone
material, it controls the passage
and attenuation of the
contaminated material to the
saturated zone.
Impact of
Vadose Zone
5
4
Indicates the ability of the aquifer
to transmit water, hence
determines the rate of flow of
contaminant material within the
groundwater system.
Hydraulic
Conductivity
3
2
After Aller et al., 1987.
