Table 2.

Weight and numerical rating values of the groundwater recharge conditioning factors

Groundwater recharge factorsWeightClassRateGroundwater recharge possibility (%)
Outcrop lithology5Beach and coastal dunes0.720.7
Dunes0.760.65
Alluvium0.80.6
Alluvium and gypsum0.750.57
Sandstone and conglomerates0.60.5
Limestone0.330.4
Green clay0.350.25
Marl and sandstone0.30.2
Slope (%)30–50.80.75
5–100.50.42
10–150.40.3
>150.350.28
Soil typeGypsum0.350.25
Clays–silt0.290.2
Silt–sands0.820.72
Sands–conglomerates0.550.45
Drainage density (m km−2)20–1.50.20.1
1.5–30.420.25
3–4.50.50.45
4.5–60.540.6
>60.60.7
Land cover3Water0.320.28
Agricultural zone0.540.43
Bare land0.450.51
Urban zone0.180.2
Lineament density (m km−2)200.120.1
0–10.20.15
1–20.310.26
2–30.420.38
3–40.460.52
Aquifer medium3Coastal dunes0.750.78
Alluvium and sand0.830.8
Alluvium and sandstone0.70.75
Vadose zone impact4Sand and gravel0.750.8
Fine sand and sandstone0.60.73
Clay sand and gravel0.450.32
Coarse sandstone0.50.47
Hydraulic head (m)52–200.80.83
20–400.750.8
40–600.650.77
60–800.60.65
80–1000.450.5
>1000.40.34
Hydraulic conductivity (m s−1)4<10−60.40.37
10−6–10−40.550.6
10−4–10−10.80.79