3. CASE STUDIES AND PRACTICAL EXPERIENCES GREECE 3.1. Sarigkiol basin 3.1.1 Vulnerability assessment 3.1.1.1 Short description Sarigkiol basin is located in the north­eastern part of Kozani Prefecture, Western Macedonia region, Greece, covering an area of 423 km 2. The mean altitude of the basin is about 952 m. The alluvial aquifer of the Sarigkiol basin covers an area of 60 km 2 and its maximum depth reach at 110 m below ground surface. In alluvial deposits a phreatic aquifer superimposed on successive confined aquifers is developed. Despite the documented heterogeneities however, it is suggested that on a regional scale a uniform aquifer may be considered. 3.1.1.2 Available data Data concerning required parameters were collected from previous studies, MSc and PhD thesis: a) Hydrogeological, hydrometeorologic and geological data. b) Drilling data including geological and hydrogeological information (depth and type of geological formations, aquifer, depth of unsaturated zone etc). c) Static water levels measurements d) Pumping test data to calculate the hydraulic parameters. The data collected are analytically presented in report on the Hydrometeorologic and geological data (Deliverable 3.1). 3.1.1.3 Results­ Elaboration of the vulnerability map Depth to groundwater (D) The water level map of the Sarigkiol basin was obtained from previous hydrogeological studies (Koumantakis 1999; Patsios, 2006). The depth to groundwater in the alluvial aquifer of Sarigkiol basin ranges from less than 7 to more than 75 m below ground surface (Fig. 1). Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 1: Depth to groundwater rating curve and water level sites position (above) and the depth to water table rating map (below). Net recharge (infiltration) (R) The variable R was calculated from rainfall data and the coefficients of infiltration of geological formations. The annual rainfall is 643 mm. Fig. 2: Net annual recharge rating curve (above) and the recharge rating map (below). Aquifer material or media (A) Aquifer media have been identified from the borehole data and 179 lithological profiles. Based on these profiles, the aquifer media was classified as: 1) Gravel, 2) Sand and Gravel, 3) Sandstone and conglomerate, 4) Sand, 5) Sand, gravel and clay, 6) Clay, sand and gravel. 1 Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 3: Aquifer media rating map. Soil media (S) The variable S (Soil type) was obtained from soil classification maps (IGME). The density of soil samples was 5 samples / Km 2 and the depth 0­30 cm from the ground surface. Based on results from soil analyses, the predominant soil types are: Clay, Silty­clay, Sandy­clay, Sandy­loam, Silty, Silty­loam, Loamy. 2 Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 4: Sampling soil position (above) and the soil media rating map (below). Topography (T) The variable T (Topography) was obtained from elevation points, using the triangulation method in ARC/INFO system (Fig. 5). The topography of the Sarigkiol basin is for the most part a flat plain, slope being generally low (1­3%), whereas a small area in the northern part of the basin reaches almost 10%. Fig. 5: Slop rating map. Impact of the vadose zone (I) The evaluation of variable I was based on data from lithological profiles. The vadose zone rating map is presented in Fig. 6. The existence of clay materials is recorded in the southern part of the basin, which result in low vulnerability values. 3 Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 6: Vadose zone rating map. Hydraulic conductivity (C) The variable C was calculated from pumping test data and bibliography data based on the properties of the aquifer materials, as well as from pumping test analyses. The hydraulic conductivity rating map is presented in Fig. 7. Fig. 7: Hydraulic conductivity rating map. DRASTIC index vulnerability The vulnerability index values were calculated using the formula 2.2.1 (Table 2). The final vulnerability DRASTIC map was produced using the international colour code and GIS (Fig. 8). 4 Programme INTEREG IIIB ARCHIMED: WATER MAP Table 2: DRASTIC index worksheet (not all sites are included). X Y DrxDwTrxTwArxAw SrxSw IrxIw CrxCw RrxRw DRASTIC 316398.744 4472665.938 40 10 12 4 4 18 6 94 316479.421 4471011.955 20 9 8 4 4 15 6 70 317426.791 4470922.928 30 9 8 8 8 15 6 84 315585.998 4471989.000 10 10 16 2 2 21 6 77 314441.005 4471462.000 5 9 12 4 4 21 6 69 313385.033 4473472.839 20 9 12 2 2 18 6 79 312072.378 4474147.961 20 9 10 12 12 15 15 89 310915.305 4473669.457 5 6 14 6 6 18 6 67 310212.055 4476978.515 40 6 8 8 8 15 6 107 308738.289 4477028.339 5 6 8 10 10 15 6 78 324183.456 4471655.376 20 10 12 4 4 18 6 90 323352.360 4471719.099 40 9 12 8 8 18 6 109 322811.001 4470114.730 10 6 10 10 10 15 6 65 322097.354 4472368.593 30 9 12 6 6 21 6 100 323104.107 4473249.190 40 8 14 6 6 24 6 130 322603.000 4473938.626 10 8 14 4 4 24 6 94 321414.315 4474388.865 10 8 10 8 8 15 6 65 Fig. 8: Vulnerability map of the Sarigkiol basin. The highest vulnerability values in the Sarigkiol basin are associated with shallow aquifers without great depth of the vadose zone. Low and very low values of vulnerability are located in the southern part of the basin in which the aquifer has great depth of vadose zone with layers of clay and silt and great depth to groundwater level (Fig. 9). 5 Programme INTEREG IIIB ARCHIMED: WATER MAP 3.2. Florina basin Florina basin is located in the central part of Florina Prefecture, Western Macedonia region, Greece, covering an area about of 319 km 2. The mean altitude of the basin is about 620 m and the mean slope 1.5%. In the area developed two aquifer systems, one alluvial aquifer covering an area about 180 km 2 and a second one in neogene deposits covering an area about 149 km 2 . 3.2.1 Elaboration of the vulnerability map Depth to groundwater (D) The depth to groundwater in the alluvial aquifer of Florina basin ranges from 0 to more than 25 m below ground surface (Fig. 9). Fig. 9: Depth to water table rating map. In general, the deeper the water levels are, the longer the pollutant takes to reach the groundwater table. Net recharge (infiltration) (R) The variable R was calculated from rainfall data and the coefficients of infiltration of geological formations. The annual rainfall is 643 mm. 6 Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 10: Net annual recharge rating curve and the recharge rating map. Aquifer material or media (A) Aquifer media have been identified from the borehole data and 85 lithological profiles. Based on these profiles, the aquifer media was classified as (Fig. 11): 1) Gravel, 2) Sand and Gravel, 3) Sandstone and conglomerate, 4) Sand, 5) Sand, gravel and clay, 6) Clay, sand and gravel. Fig. 11: Aquifer media rating map. Soil media (S) The variable S (Soil type) was obtained from soil classification maps (IGME). The density of soil samples was 5 samples / Km 2 and the depth 0­30 cm from the ground surface. Based 7 Programme INTEREG IIIB ARCHIMED: WATER MAP on results from soil analyses, the predominant soil types are: Clay, Silty­clay, Sandy­clay, Sandy­loam, Silty, Silty­loam, Loamy. Fig. 12: Soil media rating map (below). Topography (T) The variable T (Topography) was obtained from elevation points, using the triangulation method in ARC/INFO system (Fig. 13). The topography of the Florina basin is for the most part a flat plain, slope being generally low (0­3%), whereas a small area in the central part of the basin reaches almost 10%. Fig. 13: Slop rating map. 8 Programme INTEREG IIIB ARCHIMED: WATER MAP Impact of the vadose zone (I) The vadose zone is the zone of subsoil above the water table, which is unsaturated. The characteristics of the vadose zone determine the pathway and concentration of a pollutant. The evaluation of variable I was based on data from lithological profiles (Fig. 14). The vadose zone rating map is presented in Fig. 15. Fig. 14: Litholog of one representative borehole in Florina basin. Fig. 15: Vadose zone rating map. 9 Programme INTEREG IIIB ARCHIMED: WATER MAP Hydraulic conductivity (C) The variable C was calculated from pumping test data and bibliography data based on the properties of the aquifer materials, as well as from pumping test analyses. Fig. 16: Hydraulic conductivity rating map. DRASTIC index vulnerability The final vulnerability DRASTIC map was produced using the international colour code (Fig. 17). The highest vulnerability values in the Florina basin are associated with shallow aquifers without great depth of the vadose zone. Low and very low values of vulnerability are located in the center of the basin in which the aquifer has great depth of vadose zone with layers of clay and silt and great depth to groundwater level. Regional assessment of groundwater vulnerability is a useful tool for groundwater resources management and protection zoning. The results provide important information and the vulnerability maps could be used by local authorities and decision makers. The proposed methodology will be applied in other areas with similar characteristics. 10 Programme INTEREG IIIB ARCHIMED: WATER MAP Fig. 17: Vulnerability map of the Florina basin. 11 Programme INTEREG IIIB ARCHIMED: WATER MAP 3.3 Mouriki basin Mouriki basin is located in the North part of Kozani Prefecture,Western Macedonia region, Greece, covering an area of 133.6 km 2 (Fig.18).