DRASTIC parameter: A (Aquifer media). Upper Guadiana Basin (UGB).

A refers to the consolidated or unconsolidated medium that composes the aquifer. The different materials are classified into ten ranges and a rate is assigned to each class: Metamorphic/Igneous: [2] Weathered metamorphic/Igneous: [3] Thin bedded sandstone, Limestone: [4] Shale sequences: [6] Massive sandstone: [6] Massive limestone: [6] Sand and gravel: [8] Basalt: [9] Karst limestone: [10] In the Upper Guadiana Basin pilot, the geology is complex, including detrital and carbonated aquifers and the groundwater connectivity between the Upper Guadiana’s aquifer is also structurally complex. In the southern half of the Upper Guadiana Basin the aquifers are predominantly composed by limestones, with many karstified zones. Many areas in the central aquifer are formed by tertiary detrital materials. The northern aquifers are more heterogeneous. There are no large karstified areas and other formations of metamorphic materials can be found in these aquifers.