Metadata 1576

This is the fourth parameter for the DRASTIC groundwater vulnerability assessment (Aller et al. 1987) applied at the HOVER WP7 pilot area Tønder (Denmark).

This is the fifth parameter for the DRASTIC groundwater vulnerability assessment (Aller et al. 1987) applied at the HOVER WP7 pilot area Tønder (Denmark).

The Lower Oder / Odra pilot area is the only transboundary region assessing the groundwater vulnerability in GeoERA HOVER WP7 applying the DRASTIC methodology. The pilot area has an extent of about 7374 km2 and comprises parts of the groundwater catchment of the Middle and Lower Oder river of Western Poland and Eastern Germany. The considered near-surface strata consist of Cenozoic unconsolidated sediment. The assessment aims on the groundwater vulnerability to pollution of the upper useful aquifer, which ...

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 groundw...

C parameter refers to the ability of the aquifer materials to transmit water. The values of the conductivity (m/s) are classified into eight classes and a rate is assigned to each class: < 5.0*10-7: [1] 5.0*10-7 - 5.0*10-5: [2] > 5.0*10-5 - 1.5*10-4: [3] > 1.5*10-4- 3.5*10-4: [4] > 3.5*10-4- 5.0*10-4: [6] > 5.0*10-4- 1.0*10-3: [8] > 1.0*10-3 - 1.0*10-2: [9] > 1.0*10-2: [10] In the Upper Guadiana Basin pilot, the conductivity in the Upper Guadiana Basin takes values in all the ranges proposed for the classi...

D parameter represents the depth of the surface below the ground level where all the pore spaces are filled with water. The values of the depth to water (m) are classified into seven classes and a rate is assigned to each class (<1.5 m = [10]; 1.5 - 5 = [9]; 5 - 10 [7]; 10 - 15: [5]; 15 - 25: [3]; 25 - 50: [2]; >50 = [1]). In the Upper Guadiana Basin pilot, depth to water table is higher than 15 meters in most of the pilot area due to the intensive groundwater withdrawal since the early 1970s.

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 n...

R parameter represents the net recharge per unit area. The values of the recharge (mm) are classified into six classes and a rate is assigned to each class (<50 mm = [1]; 50 - 100 = [3]; 100 - 175 = [6]; 175 - 250 = [8]; 250 - 500 = [9]; >500 = [10]). In the Upper Guadiana Basin pilot, rainfall is the main source of aquifers recharge. The mean annual recharge varies between 45 and 70 mm/year.

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 ca...

T parameter represents the slope of the land surface . The values of the slope (%) are classified into five classes and a rate is assigned to each class (0 - 2 m = [10]; 2 - 6 = [9]; 6 - 12 = [5]; 12 - 18 = [3]; >18 = [1]). In the Upper Guadiana Basin pilot, the land surface is predominantly flat, sloping gently over 150 km, from the northeast (elevation 730 m.a.s.l.) to the southwest (600 m.a.s.l.).