DRASTIC parameter: I (Impact of vadose zone). Upper Guadiana Basin (UGB).

I parameter represents the unsaturated zone above the water table. The values of the vadose zone materials are classified into ten classes and a rate is assigned to each class: Silt/Clay: [1] Shale: [3] Limestone: [6] Sandstone: [6] Bedded limestone, sandstone, shale: [6] Sand and gravel with significant silt and clay: [6] Metamorphic/Igneous: [4] Sand and gravel: [8] Basalt: [9] Karst limestone: [10] In the Upper Guadiana Basin pilot, the unsaturated zone is formed by poorly permeable lithologies in the northern area and higher permeability values can be found in the sourthern part.