DRASTIC parameter: S (Soil media). Upper Guadiana Basin (UGB).

S refers to the uppermost part of the vadose zone, which is characterized by significant biological activity. The different type of soils are classified into eleven ranges and a rate is assigned to each class: Thin or absent: [10] Gravel: [10] Sand: [9] Peat: [8] Shrinking and/or aggregated clay: [7] Sandy loam: [6] Loam: [5] Silty loam: [4] Clay loam: [3] Muck: [2] Nonshrinking and nonaggregated clay: [1] The soils in the basin mainly belong to the cambisol group according to the FAO classification. It can also be found Regosol and others such as luvisol and podzol in the southeast area. The soil texture in the northern area is predominantly silty-loam, whereas the soil in the southern area is composed by peat.