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.

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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.

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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.

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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).

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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).

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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.

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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.

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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.

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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.

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Fig. 17: Vulnerability map of the Florina basin.

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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). The mean altitude of the basin is about 875 m and the mean slope is about 26.1%. The lowland area where the Drastic method had been applied covers an area of 33 km 2, with mean altitude 665m and is intensively cultivated. The main aquifer system is developed in Holocene deposits (above Neogene deposits). The depth of aquifer reaches at 160 m below ground surface.

Fig. 18: Location of Mouriki basin

3.3.1 Elaboration of the vulnerability map Depth to groundwater (D) In Holocene deposits, a sandy­clay formation superimposed on successive layers of sand­ conglomerate –gravel. Due to the existence of the sandy –clay formation, the top of main aquifer is assumed as the depth of water table. Data concerning the depth of the water table were obtained by 37 drills section (Fig. 19).

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Fig. 19: 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 lowlands of Mouriki basin with mean altitude 665 m is closed to gauge station of Ptolemaida (650m) so the data of Ptolemaida station are representative.

Fig. 20: Mean monthly rainfall (mm) fluctuation at Ptolemaida station.

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Fig. 21: Recharge rating map.

Aquifer material or media (A) Aquifer media have been identified from 35 drills section data. Based on these data, the aquifer media was classified as: 1) Conglomerates and Gravels, 2) Gravel and Sand, 3) Coarse grained sand, 4) Sand, 5) Sand and Conglomerate and Clay, 6) Sand and Clay.

Fig. 22: Aquifer media rating map.

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Soil media (S) The variable S (Soil texture) was obtained by 12 soil samples that were collected in the frame of WATER MAP project (depth 0­70 cm). According to the soil sample analysis the soil type in Mouriki basin is mainly loam sandy and sandy loam.

Fig. 23: 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. 24).

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Fig. 24: Slope 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. 25.

Fig. 25: Vadose zone rating map.

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Figure 26: Typical lithology section of drill at Mouriki basin

Hydraulic conductivity (C) The hydraulic conductivity values were calculated from the pumping tests after calculating the transmissivity, which ascribes the combination of the hydraulic conductivity (C) and the thickness (D) of the aquifer (C=T/D). Furthermore, the calculation of C was based on the specific capacity, when transmissivity data are not available. Specific capacity is defined as the ratio of discharge (Q) to drawdown (s) at the pumping borehole for a given time and is related to transmissivity by the formula T=b(Q/s), where b is a coefficient depending on the type of the aquifer and it ranges between 1.2 and 1.6.

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Fig. 27: Hydraulic conductivity rating map.

DRASTIC index vulnerability The final vulnerability DRASTIC map was produced using the international colour code (Fig. 28).

Fig. 27: Vulnerability map of the Mouriki basin.

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The highest vulnerability values in the Mouriki basin are associated with shallow aquifers without great depth of the upper sandy – clay formation. Low values of vulnerability are located in the NW and in the SE part of the basin where the vadose zone consisting of sandy and clay alternations, has great depth.

3.1.2 Remarks

3.1.2.1 Difficulties­Practical solutions to difficulties

We have faced difficulties with the parameter of hydraulic conductivity, because there were insufficient data from pumping test analyses. Data from international bibliography related hydraulic conductivity with lithological formations were used. Furthermore, during an adequate pumping period, the constant rate (Q) is estimated using a volumetric pan, while the drawdown (s) is measured. The ratio Q/s provides the aquifer transmissivity (T) at the borehole surroundings. The transimissivity, divided by the saturated depth (D) allow the determine the hydraulic conductivity: k=T/D

3.1.2.2 Quality of results

As it was aforementioned, vulnerability maps should be carefully illustrated and their reliability fully tested. The first will be a validation study, which will analyze what relationship exists between map results and groundwater quality data collected within recent years. By analyzing the statistical relationship, it is hoped that a better understanding of the relative importance of each parameter in determine the vulnerability of groundwater against external pollutants (WWRC, 1998). The quality and accuracy of data should be improved in the future. It is pointed out that, the vulnerability methods must not replace the field studies. The maps could be used as a general guide both for technicians and administrators. The choice of parameter rating should be based on prolonged studies of the hydro­geological conditions. Further investigations are required in order to understand the mechanisms of groundwater recharge and pollutant transport in the aquifer.

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3.1.2.3 Practical utility of results

The results provide important information and the vulnerability maps could be used by local authorities, regulators, managers of land and water resources and decision makers. The vulnerability maps provide a relative indication of where groundwater contamination is more likely to occur. It allows to know and to point out where the protection of groundwater must be a determinant factor to consider in order to preserve the soil and the quality of aquifers. The vulnerability map should be overlaid on the pollution sources map. This is essential step in order to find out whether any possible pollution sources (e.g. farm, factory etc) lay within the high vulnerability zones. Furthermore, WATER­MAP project has the following specific objectives: • To establish a network of the Archimed areas that face similar risks of groundwater pollution. • To exchange information on the existing level of knowledge on the state of groundwater resources and their vulnerability in the participating regions, as well as on existing policies and legislation. • To incorporate the produced results in a spatial monitoring system for the identification of environmental risks. Finally, the vulnerability map will be a useful both for researchers and for water managers and will contribute to the protection and conservation of the most precious natural resource: the water.

3.1.2.4 Tools for the practical management of groundwater resources

Based on results of WATER map project, a rational management should be applied in the study areas. The following recommendations are proposed in order to protect the groundwater quality in pilot areas: • To present the network’s results to regional policy makers. • To develop a Decision Support System that will use all information and offer water management guidance. • To disseminate all information and consult with the public through the organization of special events and through the establishment of a public dialogue mechanism. • To incorporate groundwater management considerations in regional and spatial development policies. 20 Programme INTEREG IIIB ARCHIMED: WATER MAP

• To extent the network to additional local and regional authorities, industry, NGOs, educational and research institutions, etc. • Training courses should be organized in order to educate people in using methods to optimize water use. • Planning of surface water protection measures, such as industrial and domestic effluent disposal in torrents, as well as construction of proper landfills, which are environmentally compatible. References

Al­Adamat, R.A.N., Foster, I.D.L., Baban, S.M.J. (2003): Groundwater vulnerability and risk mapping for the basaltic aquifer of the Azraq basin of Jordan using GIS, Remote sensing and DRASTIC. Applied Geography 23, 303­324. Aller, L., Bennet, T., Lehr, JH., Petty, RJ., Hackett, G. (1987): DRASTIC: a standardized system for evaluating groundwater pollution potential using hydrogeological setting. EPA/600/2­87/035. US Environmental Protection Agency, 163 p. Al­Zabet, T. (2002): Evaluation of aquifer vulnerability to contamination potential using the DRASTIC method. Environmental Geology 43, 203­208. Civita, M. (1994): Le carte della vulnerabilità degli acquiferi all’ inquinamento. Teoria & practica. (Aquifer vulnerability maps to pollution). Pitarora Ed., Bologna (in Italian). Civita, M., Regibus, C. (1995): Sperimentazione di alcune metodologie per la valutazione della vulnerabilita degli aquiferi. Quaderni di Geologia Applicata, Pitarora Ed., Bologna (in Italian). Corniello, A., Ducci, D., Napolitano, P. (1997): Comparison between parametric methods to evaluate aquifer pollution vulnerability using GIS: an example in the Piana Campana, Southern Italy. In: Marinos P., Koukis G., Tsiambaos G., Stournaras G. (Eds). Engineering Geology and the Environment, Balkema, Rotterdam, 1721­1726. Cost Action 620 (2003): Vulnerability and Risk Mapping for the Protection of Carbonate (Karst) aquifers. Final report. Francois Zwahlen (Chairman, Editor in Chief). Dimitrakopoulos, D. (2001): Hydrogeological conditions of Amyntaion pit. PhD Thesis, Technical University of Athens. Dept. of Mechanical and Metallurgical Eng. 204 p. Diputacion de Alicante (2004): Vulnerability map to groundwater pollution. DRASTIC method. www.dip­alicante.es. Doerfliger, N., Jeannin, P.Y., Zwahlen, F. (1999): Water vulnerability assessment in karst environments: a new method of defining protection areas using a multi­attribute approach and GIS tools (EPIK method). Env. Geology 39 (2), 165­176. Gogu, R.C. & Dessargues, A. (2000): Sensitivity analysis for the EPIK method of vulnerability assessment in a small karstic aquifer, S. Belgium. Hydrogeology Journal (2000) 8:337­345. Institute of Geological and Mineral Exploration, IGME (2001): Quality control and hydrogeological study of Western Macedonia. IGME, Technical report (Unpublished). Institute of Geological and Mineral Exploration IGME (2001): Soil and Soil­chemical study of Kozani­Ptolemaida­Amyntaion region. Technical report (Unpublished). Koumantakis, J. (1999): Assessment and water resources management in Sarigkiol basin, Kozani prefecture. Technical report. National Technical University, Athens (in Greek, Unpublished). Panagopoulos, G., Antonakos, A., Lambrakis, N. (2005): Optimization of the DRASTIC method for groundwater vulnerability assessment via the use of simple statistical methods and GIS. Hydrogeology Journal, DOI 10.1007/s10040­005­0008­x. Patsios, E. (2006): Application of DRASTIC method to assess the groundwater vulnerability: A case study from alluvial aquifer of Sarigkiol basin. M.Sc. dissertation submitted to Dept. of Geology, Aristotle University of Thessaloniki (supervisor K. Voudouris). Stamou A. (2001): Hydrogeological study of the alluvial aquifer in Sarigkiol basin. Institute of Geological and Mineral Exploration (IGME) (in Greek).

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Secunda, S., Collin, M.L., Melloul, A. (1998): Groundwater vulnerability assessment using a composite model combining DRASTIC with extensive agricultural land use in Israel’s Sharon region. Journal of Environmental Management 54, 39­57. Uricchio, V.F., Giordano, R., Lopez, N. (2004): A fuzzy knowledge­based decision support system for groundwater pollution risk evaluation. Journal of Environmental Management 73, 189­197. Voudouris, K., Mandilaras, D. (2004): Evaluation of groundwater vulnerability using the DRASTIC method: Case study of alluvial aquifer of Glafkos basin, Achaia. Hydrotechnika. Journal of the Hellenic Hydrotechnical Association. Vol. 14, December 2004, 17­30 (in Greek). Wyoming Water Resources Center (WWRC) (1998): Wyoming groundwater vulnerability assessment handbook. SDVC, Report 98­01. Zektser, I.S., Everett, L.G. (2004): Groundwater resources of the world and their use. UNESCO. IHP­ VI, Series on groundwater No 6.

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