Table 1 Significant methods for evaluating groundwater vulnerability to contamination for resource protection (adapted from [56])
From: DRASTIC, GOD, and SI approaches for assessing groundwater vulnerability to pollution: a review
Methods | Equation | Parameters | Aquifer type | Source |
|---|---|---|---|---|
DRASTIC | \(\mathrm{DRASTIC Index}={\sum }_{i=1}^{7}W\mathrm{iRi}\) | Wi and Ri weight and rating for the ith parameter, respectively (range of parameters are given [5] | Â | [5] |
GOD | IvGOD = GR × OR × DR | G = groundwater type, O = lithology for unsaturated zone, D = depth of groundwater, R = rating of parameters |  | [31] |
SI | IvSI = DnDp + RnRp + AnAp + TnTp + LUnLUp | D = depth to water table, R = net recharge, A = water ground media, T = topography, LU = land use, n = score for each parameter, p = weighting factor given to each parameter |  | [69] |
SINTACS | \(Iv= \sum_{i=1}^{7}\sum_{j=1}^{n}(\mathrm{Pi }\times \mathrm{Wi})\) | Pi = rating for the ith parameter, and Wj = associated weight for the jth weight classification | Porous media aquifers | [18] |
GALDIT | \({I}_{GALDIT} = \frac{{\sum }_{i=1}^{6}(Wi\times Ri)}{{\sum }_{i=1}^{6}Wi}\) | Wi = weight of the ith indicator; Ri = rating of the ith indicator |  | [16] |
AVI Rating system | \(c ={\sum }_{i =1}^{n}\frac{dj}{ki}\) | n = number of sedimentary layers above the aquifer; d = thickness of each sedimentary unit, and k = estimated hydraulic conductivity of each sedimentary unit |  | [85] |