Table 4 Principal types of land use and their assigned ratings and weight provided by the Instituto Geogrà fico Português (2001)
From: DRASTIC, GOD, and SI approaches for assessing groundwater vulnerability to pollution: a review
Land use parameter | Rating | Weight |
|---|---|---|
Agricultural areas | 0.222 | |
 Irrigation perimeters (annual crops), paddy fields | 90 | |
 Permanent crops (orchards, vineyards) | 70 | |
 Heterogeneous agricultural areas | 50 | |
 Pastures and agro-forested areas | 50 | |
Artificial areas | ||
 Industrial waste discharges, landfills | 100 | |
 Quarries, shipyards, open-air mines | 80 | |
 Continuous urban areas, airports, harbors, (rail)roads, areas with industrial or commercial activity, laid out green space | 75 | |
 Discontinuous urban areas | 70 | |
Natural area | ||
 Aquatic environments (salt marshes, salinas, intertidal zones) | 50 | |
 Forests and semi-natural zones | 0 | |
 Water bodies | 0 | |