AHP-GIS Based DRASTIC Model for Groundwater Vulnerability to Pollution Assessment: A Case Study of Hazaribag District, Jharkhand, India

Transcription

1 AHP-GIS Based DRASTIC Model fo Goundate Vulneability to Pollution Assessment: A Case Study of Hazaibag Distict, Jhakhand, India P. Tikey, A. K. Goai, J. Iqbal* Envionmental Science & Engineeing Goup, Bila Institute of Technology, Mesa, Ranchi , India * jaed@bitmesa.ac.in Abstact- Goundate pollution due to anthopogenic activities is one of the most seious envionmental poblems in uban/industial aeas. Goundate is one of the main souces of dinking ate in Hazaibag Distict and hence its vulneability assessment to delineate aeas that ae moe susceptible to contamination is vey impotant. The pesent study aims to demonstate AHP-GIS based DRASTIC model to estimate the elative pobability of contamination of the goundate esouces in the selected study aea. The study esult eveals that the vulneability index vaying fom 4.53 to 9.47 (Scale: Minimum possible Index and Maximum possible index- 9.84). The ange of the vulneability index has been classified into five classes (lo, modeately lo, modeate, modeately high, and high) and accodingly the hole study aea is classified into five types of zones on the basis of vulneability index. The study esults delineate aeas that ae moe susceptible to contamination due to the existing hydo-geologic factos and sho aeas of geatest potential fo goundate contamination. Keyods- AHP; Goundate Vulneability Assessment; DRASTIC; GIS; Hazaibag Distict I. INTRODUCTION Goundate is the most impotant ate esouce on eath [1]. The quality of goundate is geneally unde a consideable potential of contamination especially in agicultue-dominated aeas ith intense activities that involve the use of fetilizes and pesticides [2-6]. The issue of potection of goundate against pollution is of cucial significance [7]. The concept of goundate vulneability is a conestone in the evaluation of the isk of goundate contamination and in the development of management options to peseve the quality of goundate [8-10]. Goundate vulneability studies ae based on the idea that specific land aeas ae moe vulneable to goundate contamination than othes [11]. Hence, goundate vulneability assessment delineates aeas that ae moe susceptible to contamination due to the hydogeologic factos and anthopogenic souces and shos aeas of geatest potential fo goundate contamination. In geneal, this connotes the estimation of the potential fo contaminants to migate fom the land suface though the unsatuated zone (chaacteised by poe spaces that ae incompletely filled ith ate) until eaching the aeas of inteest [12]. As such, the concept of goundate vulneability is impotant fo a ational management of goundate esouces and subsequent land use planning [12-14]. Goundate vulneability maps povide useful infomation to potect goundate esouces and evaluate the potential fo ate quality impovement ith changes in agicultual pactices and land use applications [12-15]. The use of goundate vulneability assessment in planning, policy analysis, and decision making vaies and eflects diffeent aspects including (but not limited to): (i) advising decision makes of the need fo adopting specific management options to mitigate the quality of goundate esouces; (ii) elucidating the implications and consequences of thei decisions; (iii) poviding diection fo allotting ate esouces; (iv) enlightening decisions about land use pactices and activities; and (v) educating the geneal public about the potential fo goundate contamination thoughout public aaeness campaigns [16]. The concept of aquife vulneability to extenal pollution as intoduced in 1960s by Magat, 1968 [17], ith seveal systems of aquife vulneability assessment developed in the folloing yeas (Alle et. al., 1987 [18]; Civita, 1994 [19]; Vba & Zapoozec, 1994 [20]; Sinan & Razack, 2009 [21]; Polemio et. al., 2009 [22]; Foste, 1987 [23]). They found that the eason behind the diffeent vulneability is the diffeent hydo-geological settings. Many appoaches have been developed to evaluate aquife vulneability. These include pocess based methods, statistical methods, and ovelay/index methods [24, 25]. The pocess based methods use simulation models to estimate the contaminant migation [26]. Statistical methods use statistics to detemine associations beteen the spatial vaiables and the actual occuence of pollutants in the goundate. While the ovelay/index methods use location specific vulneability indices based on the factos contolling movement of pollutants fom the gound suface to the ate beaing stata. Of these majo appoaches, the ovelay/index method has been the most idely adopted appoach fo lage scale aquife sensitivity and goundate vulneability assessments. Scientists stated to give pedictions of goundate pollution potential based on hydo-geological settings [22, 27-38]. In this pape, AHP-GIS based

2 DRASTIC model is demonstated fo the study. The main objective of this pape is to assess goundate vulneability to pollution of the aquife situated in the study aea using the AHP-GIS based DRASTIC model in combination. II. STUDY AREA Hazaibag Distict as shon in Fig. 1 as taken up fo this study. It is a medium-size fast going uban cente Jhakhand State in India. The study aea is situated in N and E. It coves appoximately 4500 km 2 of aea. The distict compises of 11 blocks, namely Hazaibagh, Chaupaan, Bahi, Padma, Ichak, Bakatha, Bishungah, Katkamsandi, Keedai, Bakagaon and Chuchu as shon in Fig. 1. Fig. 1 Study aea map The aveage annual ainfall is 1347 mm. The maximum tempeatue duing peak summe goes up to 46 0 C and minimum duing peak inte dops don to 4 0 C. The aveage elevation of Hazaibagh Distict vaies fom m fom mean sea level. Geologically the aea is undelain by Chotanagpu ganite gneiss, phyllite mica-schist. It is unifomly ovelain by loe Gondana fomations consisting of sandstone, shales and coal seams. Ganite ocks shoed maximum thickness of eatheed mantle in favouable topogaphic and dainage condition. To types of aquifes (unconfined and confined) ae mainly obseved in both Ganite-gneiss and Gondana ocks. Unconfined aquife (an aquife undelain by an impemeable statum, but the top of the aquife consists of soil layes that ae pemeable enough to povide easy passage of ate) is obseved in eatheed fomations heeas semi-confined (an aquife undelain by an impemeable statum and bounded at the top by soil layes of elatively lo pemeability) to confined aquifes (an aquife bounded both at the bottom and at the top by an impemeable statum and fully filled ith ate hich is usually unde pessue) ae in deepe factues. Wate levels in unconfined aquifes vay beteen 3-10 mbgl. Piezometic head in Ganite-gneiss vaies beteen 2-9 mbgl. In Gondana ocks it vaies beteen mbgl in Bhukunda aea and 6-9 mbgl in Ghato, Banji aea. III. MATERIALS AND METHODOLOGY Goundate vulneability of the study aea as evaluated using hydogeologic paametes that can affect the contaminants tanspot though the vadose zone to the ate table using DRASTIC method [18]. Each of the seven DRASTIC hydogeological paametes (Depth to ate table, Net echage, Aquife media, Soil media, Topogaphy, Impact of vadose zone and Hydaulic conductivity) is mapped and classified eithe into anges o into significant media types, hich have an impact on pollution potential. Each facto o paamete is assigned a subjective ating. Weight multiplies ae then used fo each facto to balance and enhance its impotance. The final vulneability map is based on the DRASTIC Index (DI) hich is computed as the eighted sum ovelay of the seven layes using the folloing equation: DI D D R R A A S S T T I I C C (1) Whee, D, R, A, S, T, I, and C epesents the seven paametes, is the ating value, and the eight assigned to each paamete. Whee; D = Ratings to the depth to ate table D = Weights assigned to the depth to ate table R = Ratings fo anges of aquife echage R = Weights fo the aquife echage A = Ratings assigned to aquife media A = Weights assigned to aquife media S = Ratings fo the soil media

3 S = Weights fo soil media T = Ratings fo topogaphy (slope) T = Weights assigned to topogaphy I = Ratings assigned to vadose zone I = Weights assigned to vadose zone C = Ratings fo ates of hydaulic conductivity C = Weights given to hydaulic conductivity The flo chat in Fig. 2 shos the geneal ovevie of the oking methodology. Identification of input hydo-geological paametes Seconday data collection fo each hydogeological paamete Classification of the existing condition into Ranges and assign Ratings as pe DRASTIC model Detemination of eightage fo each input paamete using Analytical Hieachy Pocess (AHP) Geneation of thematic layes fo each input paamete in GIS Ovelaying each laye to obtain the final vulneability map Fig. 2 Flo chat of the oking methodology The ok has been completed ith the folloing steps: A. Page Layout IV. ASSESSMENT OF AQUIFER VULNERABILITY TO POLLUTION The data has been geneated fom vaious published epots/maps of CGWB, JSAC and satellite data, etc. Vaious data types and thei souces to geneate the thematic layes of diffeent hydogeological paametes ae shon in Table 1. B. Assigning Ranges and Ratings TABLE 1 DATA TYPES AND ITS SOURCES FOR CREATION OF OUTPUT LAYERS Sl. No. Data Type Souce Output Laye 1 Well data CGWB, Ranchi Depth to ate 2 Aveage annual ainfall CGWB, Ranchi Net echage 3 Geologic map JSAC Aquife media 4 Soil map JSAC Soil media 5 SRTM data USGS GLOVIS visualisation viee Topogaphy 6 Soil map JSAC Impact of vadose zone 7 Geologic map JSAC Hydaulic conductivity The anges and atings fo each paamete have been assigned similaly to the standadized DRASTIC system given by [18] fo evaluating goundate pollution potential using diffeent hydogeologic settings. Each DRASTIC facto has been divided into eithe anges o significant media types that affect goundate vulneability. The media types such as aquife mateial, soil type and impact of vadose zone, cannot be measued numeically. Each ange of each DRASTIC paamete has been evaluated ith espect to the othes to detemine its elative significance to pollution potential, and has been assigned a ating of 1 to 10. The most vulneable ange is given the ating 10, and the least vulneable the ating 1. Evey paamete in the model has a fixed eight indicating the elative influence of the paamete in tanspoting contaminants to the goundate. The DRASTIC paametes D, R, A, S, T, I and C have been assigned one value each ange o a typical value. Ratings of each paamete ae shon in Table 2, hich vay fom 1 to 10, ith highe values descibing geate pollution potential. The numeical atings, hich ee established using the Delphi technique [18], ae ell defined and have been used oldide [14, 39-42]. The atings fo each paamete ae listed in Table 2 fo all the anges and types

4 TABLE 2 RANGES AND RATINGS FOR VARIOUS HYDRO-GEOLOGICAL SETTINGS [18] Depth to Goundate Net Rechage Ranges (m) Ratings (D ) Sub-Index (D *D ) Ranges (cm) Ratings (R ) Sub-Index (R *R ) Weight (D ) 5 Weight (R ) 4 Aquife Type Soil type Type Ratings (A ) Sub-Index (A *A ) Type Ratings (S ) Sub-Index (S *S ) Massive Shale 2 6 Thin o absent Metamophic/ Igneous 3 9 Gavel Weatheed Metamophic/ Igneous 4 12 Sand 9 18 Glacial Till 5 15 Peat 8 16 Bedded sandstone, Shinking and/o Limestone and Shale 6 18 Aggegated Clay sequences 7 14 Massive Sandstone 6 18 Sandy Loam 6 12 Massive Limestone 6 18 Loam 5 10 Sand and Gavel 8 24 Silty Loam 4 08 Basalt 9 27 Clay loam 3 06 Kast Limestone Muck 2 04 Non-shinking and Weight (A ) 3 Non-aggegated Clay 1 02 Topogaphy o slope Weight (S ) 2 Ranges (in Pecent) Ratings (T ) Sub-Index (T *T ) Impact of Vadose Zone Type Ratings (I ) Sub-Index (I *I ) Confining laye Silt/ Clay Shale Limestone 6 30 Weight (T ) 1 Sandstone 6 30 Hydaulic Conductivity Bedded Limestone, Sandstone, Shale 6 30 Sand and Gavel Range (m/d) Ratings (C ) Sub-Index (C *C ) ith significant Silt 6 30 and Clay Metamophic/ Igneous Sand and Gavel Basalt Kast Limestone Weight (C ) 3 Weight (I ) 5 1) Detemination of Weightage fo Each Paamete: Analytical Hieachical Pocess (AHP) is an appoach to decision making that involves stuctuing multiple choice citeia onto a hieachy, assessing the elative impotance of these citeia, compaing altenatives fo each citeion and detemining an oveall anking of the altenatives. The foundation of the Analytic Hieachy Pocess (AHP) is a set of axioms that caefully delimits the scope of the poblem envionment [43]. It is based on the ell-defined mathematical stuctue of consistent matices and thei associated ight eigenvecto's ability to geneate tue o appoximate eights, [44-46]. The AHP methodology compaes citeia, o altenatives ith espect to a citeion, in a natual, pai ise mode. To do so, the AHP uses a fundamental scale of absolute numbes that have been poven in pactice and validated by physical and decision poblem expeiments. The fundamental scale has been shon to be a scale that captues individual pefeences ith espect to quantitative and qualitative attibutes just as ell o bette than othe scales [45, 46]. It convets individual pefeences into atio scale eights that can be combined into a linea additive eight (a) fo each altenative a. The esultant (a) can be used to compae and ank the altenatives, and hence assist the decision make in making a choice. Given that the thee basic steps ae easonable desciptos of ho an individual comes natually to esolve a multi-citeia decision poblem, then the AHP can be consideed to be both a desciptive and pesciptive model of decision making. The AHP is pehaps the most idely used decision making appoach in the old today. Its validity is based on the many hundeds (no thousands) of actual applications in hich the AHP esults ee accepted and used by the cognizant decision makes (DMs) [46]. Each input paamete has a pedetemined, fixed and elative eight that eflects its elative impotance of goundate

5 vulneability to pollution. The most significant factos have a highe eight and vice-vesa. The pollutant s eights have been detemined using AHP. The detailed methodology is explained belo to detemine the elative eightage of each pollutant. The eightage of individual pollutants can be found out using AHP. AHP is a systematic method fo compaing a list of objectives o altenatives. This method foms a pai-ise compaison matix A as shon belo, hee the numbe in the i th o and j th column gives the elative impotance of individual paamete P i as compaed ith Pj. The compaison matix geneated by autho s expetise using Saaty s scale [45] is shon belo in matix A. The elative eightage can be impoved by taking the expets vies. A = [ ] The sum of each column and then division of each column by the coesponding sum ae computed to obtain the nomalize eights, the nomalized matix N, thus obtained is epesented in matix N as given belo. N = [ ] The elative eight vecto W fo the pollutants is given by the aveage of the o elements in matix N as Thus, the sum of the eightage of the pollutants obtained as by hee, CI CR CI RI max n n 1 n RI n Since, CR < 0.1, the judgements ae acceptable A n n ) Geneation of Thematic Layes fo Each Dastic Paamete: 7. The consistency ation of the matix can be checked Thema tic layes fo each hydogeological paamete ee geneated using Ac GIS softae. Diffeent souces of a data (mentioned above) have been used fo the geneation of individual thematic laye. The flo chat fo the geneation of layes is shon in Fig

6 Ra Data Depth to ate table Pocessing in GIS to Geneate Thematic Layes Depth to ate table Ovelaying each layes to obtain Final Output Rainfall & Evapo-tanspiation Geological Repot Soil Data Topogaphy Net Rechage Aquife Media Soil Media Slope Goundate Vulneability to Pollution Map Soil Data Geogaphical Repot Impact of Vadose zone Hydaulic Conductivity Fig. 3 Flo chat fo geneation of layes fo input paametes using Ac GIS The detailed methodology fo geneation of thematic layes is given belo: Depth to Wate Table: The depth-to-ate table paamete as deived fom ate level data collected fom Cental Gound Wate Boad (CGWB), Ranchi. The depth-to-ate table is shallo and has a ange of mbgl. The ell data as then used to geneate the map fo depth to ate table contoued by intepolating using Invese Distance Weighted method. The study aea as extacted using the distict bounday as a mask. The map thus obtained as eclassified into thee anges that fit the DRASTIC model. The thee eclassification anges and thei assigned atings ae shon in Table 3. The map thus geneated fo depth to ate is shon in Fig. 4. TABLE 3 RANGES AND RATINGS FOR VARIOUS HYDRO-GEOLOGICAL SETTINGS USING DRASTIC DATA FOR THE STUDY AREA Depth to Goundate Ratings Ranges (m) (D ) Sub-Index (D *D ) Net Rechage Ratings Ranges (cm) (R ) Sub-Index (R *R ) Weight (D ) Weight (R ) Aquife Media Soil Media Ratings Sub-Index Ratings Sub-Index Type Type (A ) (A *A ) (S ) (S *S ) Metamophic /igneous Coase Loamy Weatheed metamophic igneous Loamy & loamy skeletal Bedded sandstone, shale sequences & massive sandstone Fine & fine loamy Sand & Gavel Basalt Weight (A ) Weight (S ) Topogaphy o slope Ratings Ranges (in Pecent) (T ) Sub-Index (T *T ) Type Impact of Vadose Zone Ratings (I ) Sub-Index (I *I ) Fine & fine loamy Loamy Loamy skeletal & coase loamy Weight (T ) Hydaulic Conductivity Ratings Range (m/d) (C ) Sub-Index (C *C ) Weight (C ) Weight (I )

7 Fig. 4 Depth to ate table Net Rechage: The map fo pecipitation as geneated using the ainfall data collected fom CGWB, Ranchi. The evapotanspiation map as pepaed consideing evapotanspiation as 5% of the pecipitation (value taken fom a epot of Bisa Agicultual Univesity (BAU) fo ainfall and evapotanspiation elationship in Jhakhand State). The unoff coefficient anges fom 0-1 depending on the land use type. Due to lack of data the unoff coefficient fo this study has been consideed as 0.5. Then the map fo net echage as geneated using aste calculato by the fomula of net echage as the amount of pecipitation minus evapotanspiation and unoff. The eclassification as done accoding to the anges and coesponding atings. Due to homogeneity in net echage fo the entie distict has single ange (25.4+) ith ating (9) as in Table 2 and the subindex of the same is epoted in Table 3. The map thus geneated fo net echage is shon in Fig. 5. Fig. 5 Net echage Aquife Media: Aquife media map as pepaed fom the geologic map of Jhakhand. The study aea consists of diffeent types of aquife media hich ee eclassified into five types and thei coesponding ating as assigned fo each aquife media as given in Table 3. The map thus geneated is shon in Fig. 6. Soil Media: Soil media map as pepaed fom the soil map of Jhakhand. The study aea consists of fine to coase loamy type soil. The soil type existing in the study aea as classified into thee types and thei coesponding atings ee assigned fo each type of soil media as given in Table 3. The map geneated fo soil media is shon in Fig. 7. Topogaphy: The topogaphy map as pepaed using the Shuttle Rada Topogaphy Mission (SRTM) data. The pecentage slope aste file as ceated fom Digital Elevation Model (DEM) using Spatial Analyst. The slope in the study

8 aea vaies fom 0-18 pecent. Reclassification as done fo the pecent slope aste in the anges of 0 to 18% into five classes and assigned thei coesponding atings as given in Table 3. The map of topogaphy is shon in Fig. 8. Fig. 6 Aquife media Fig. 7 Soil media Fig. 8 Slope map

9 Impact of vadose zone: Due to unavailability of Vadose Zone data in the study aea, infomation of the soil media as used to deive the appoximate atings fo Vadose zone. The map as conveted to a aste data by defining atings fo the vadose zone media (using soil media data) (Table 3 & Fig. 7). The map of impact of vadose zone is shon in Fig. 9. Hydaulic Conductivity: Due to unavailability of hydaulic conductivity data in the study aea, infomation of the aquife media as used to deive the appoximate atings fo hydaulic conductivity. It as conveted to a aste data accoding to the defined atings. The atings of the hydaulic conductivity ee assigned (using aquife media data instead hee) in Table 3. The map of hydaulic conductivity is shon in Fig. 10. Fig. 9 Impact of Vadoze zone Fig. 10 Hydaulic conductivity V. RESULTS AND DISCUSSION The hydogeological settings of Hazaibag Distict ith thei anges and atings ae listed in Table 3. The final vulneability map as obtained by unning the model in the AcGIS 9.2 envionment by using the seven hydo-geological data layes. The map thus obtained is shon in Fig. 11. The vulneability index as eclassified into five classes that descibe the elative pobability of contamination of the goundate esouces. These five classes ae: lo, modeately lo, modeate, modeately high, and high. A egional scale has been used fo compaing the elative vulneability of goundate esouces. The vulneability index class fo final vulneability map is given belo in Table 4. The esult of goundate vulneability to pollution assessment shos index values hich vay fom 4.53 to The possible vulneability indices vay fom 1 to 9.84, if calculated fom Table 2. The maximum and minimum vulneability indices ae calculated by sum of the poduct of maximum and minimum atings fo all the paametes ith its coesponding eightage espectively. The esults of the goundate vulneability assessment sho that the study aea has been divided into five zones of elative vulneability: lo goundate vulneability isk zone (index: <5.36); modeately lo vulneability isk

10 zone (index: ), modeate vulneability zone (index: ), modeately high vulneability zone (index: ), and high vulneability zone (index: >7.46) hich is shon in Table 4. Fig. 11 Relative potential of goundate vulneability to pollution map TABLE 3 RANGES, RATINGS AND WEIGHTAGE OF DRASTIC PARAMETERS = = 8.47 = = 4.53 TABLE 4 VULNERABILITY INDEX, CLASS AND CORRESPONDING AREA Vulneability Class DRASTIC Index Aea in km 2 Pecentage of aea Lo < Modeately Lo Modeate Modeately High High Total Aea It is vey difficult to say the ole of paticula paamete on the spatial changes in the vulneability index. But the vulneability map clealy eveals that the depth to goundate has significant ole in spatial changes in vulneability index. It is clea fom the map that the highe the goundate depth (15-30 ft), the loe the vulneability class. Since, the net echage facto is constant thoughout the study aea and thus does not have any influence on the spatial changes in the vulneability index. The highe class of vulneability index is moe o less influenced by soil media and aquife media. The total aea unde diffeent vulneability classes and thei coesponding pecentages is epoted in Table 4. The esults evel that the pecentages of aea (total aea) unde diffeent vulneability class ae 18% ( km 2 ), 57.9% ( km 2 ), 11% ( km 2 ), 10.3% ( km 2 ), and 2.8% ( km 2 ) fo lo, modeately lo, modeate, modeately high and high espectively. The high vulneability zones ae mainly lie in the blocks of Ichak, Katkamsandi, and Sada. VI. CONCLUSION Goundate plays an impotant ole in dinking ate supply in Hazaibag Distict. This study utilized DRASTIC model and GIS technique to assess the aquife vulneability in the study aea. Seven envionmental paametes hich include depth to ate, net echage, aquife media, soil media, topogaphy, impact of vadose zone, and hydaulic conductivity ee used to epesent the hydo geological setting of the study aea. The esult of goundate vulneability to pollution assessment shos index values hich vay fom 4.53 to 8.47 (Scale: Min- 1 and Max- 8.16). Accoding to the esults of the goundate vulneability assessment, the study aea has been divided into five zones of elative vulneability: lo, modeately lo,

11 modeate, modeately high and high vulneability zone. The maximum aea has fallen unde modeately lo vulneable zone, accounting fo 57.9% ( km 2 ). The study suggests that the DRASTIC model can be used fo pioitization of vulneable aeas in ode to pevent the futhe pollution to aleady moe polluted aeas. Thee is a need to develop a system that can be used to identify aeas hee attention o potection effot is equied. Thee should be a detailed and fequent monitoing in high and modeately high vulneable zones in ode to monito the changing level of pollutants. The above study also helps fo sceening the site selection fo aste dumping. The measuement of elative gound-ate vulneability to pollution may be one of many citeia used in siting decisions, but should not be the sole citeia. ACKNOWLEDGEMENT The authos ish to thank Diecto JSAC, CGWB & BAU fo the data equied to accomplish the ok. REFERENCES [1] J. P. Villeneuve, O. Banton, and P. Lafance, A pobabilistic appoach fo the goundate vulneability to contamination by pesticides: The VULPEST model. Ecological Modelling, vol. 51, pp , [2] T. W. Giambelluca, K. Loague, Geen R E, and M. A. Nullet, Uncetainty in echage estimation: Impact on goundate vulneability assessments fo the Peal Habo Basin, O ahu, Haai i, USA. Jounal of Contaminant Hydology, vol. 23, pp , [3] M. Soutte, and A. Musy, Coupling 1D Monte-Calo simulations and geostatistics to assess goundate vulneability to pesticide contamination on a egional scale. Jounal of Contaminant Hydology, vol. 32. pp , [4] I. R. Lake, A. A. Lovett, K. M. Hiscock, M. Betson, A. Foley, G. Sunnenbeg, S. Eves, and S. Fletche, Evaluating factos influencing goundate vulneability to nitate pollution: Developing the potential of GIS. Jounal of Envionmental Management, vol. 68, pp , [5] A. Thapinta, and P. Hudak, Use of geogaphic infomation systems fo assessing goundate pollution potential by pesticides in Cental Thailand. Envionmental Intenational, vol. 29, pp , [6] G. Chae, K. Kim, S. Yun, S. Kim, B. Choi, H. Kim, and C. W. Rhee, Hydogeochemisty of alluvial goundate in an agicultual aea: An implication fo goundate contamination susceptibility. Chemosphee, vol. 55, pp , [7] I. S. Zektse, O. A. Kaimova, J. Bujuoli, and M. Bucci, Regional estimation of fesh goundate vulneability: methodological aspects and pactical applications. Wate Resouces, vol. 31, pp , [8] B. Fobe, and M. Goossens, The goundate vulneability map fo the Flemish egion: its pinciples and uses. Engineeing Geology, vol. 29, pp , [9] F. Woall, T. Besien, and D. D. Kolpin, Goundate vulneability: Inteactions of chemical and site popeties. The Science of the Total Envionment, vol. 299, pp , [10] F. Woall, and T. Besien, The vulneability of goundate to pesticide contamination estimated diectly fom obsevations of pesence o absence in ells. Jounal of Hydology, vol. 303, pp , [11] R. C. Gogu, and A. Dassagues, Cuent tends and futue challenges in goundate vulneability assessment using ovelay and index methods. Envionmental Geology, vol. 39, pp , [12] L. D. Connell, and G. Daele, A quantitative appoach to aquife vulneability mapping. Jounal of Hydology, vol. 276, pp , [13] M. G. Rupet, Calibation of the DRASTIC goundate vulneability mapping method. Gound Wate, vol. 39, pp , [14] I. S. Babike, A. M. Mohamed, T. Hiyama, and K. Kato, A GIS-based DRASTIC model fo assessing aquife vulneability in Kakamigahaa Heights, Gifu Pefectue, Cental Japan. Science Total Envionment, vol. 345, pp , [15] M. R. Bukat, and J. Fehe, Regional estimation of goundate vulneability to non-point souces of agicultual chemicals. Wate Science and Technology, vol. 33, pp , [16] National Reseach Council (NRC) (1993) Goundate Vulneability Assessment: Pedicting Relative Contamination Potential unde Conditions of Uncetainty. National academy pess, Washington. [17] J. Magat, Goundate vulneability to contamination. 68, BRGM, Oleans, Fance. In: Massone et. al., (2010) Enhanced goundate vulneability assessment in geological homogeneous aeas: A case study fom the Agentine Pampas. Hydogeol J. vol. 18, pp , [18] L. Alle, T. Bennett, J. H. Leh, and R. J. Petty (1987) DRASTIC: A standadized system fo evaluating goundate pollution potential using hydogeologic settings. USEPA, Robet S. Ke Envionmental Reseach Laboatoy, Ada, OK. EPA/600/2 85/0108 [19] M. Civita (1994) Le cate della vulneabilità degli acquifei all inquinamento. Teoia and pactica. (Aquife pollution vulneability maps). Pitaoa Ed., Bologna (in Italian) [20] J. Vba, A. Zapoozec (1994) Guidebook on mapping goundate vulneability. Int. Association of Hydogeologists. Int. Contibutions to Hydogeology; 16. Velag Heinz Heise, Hannove. [21] Sinan Mohamed, and Moumtaz Razack, An extension to the DRASTIC model to assess goundate vulneability to pollution: application to the Haouz aquife of Maakech (Moocco). Envion Geol, vol. 49, pp , [22] M. Polemio, D. Casaano, and P. P. Limoni, Kastic aquife vulneability assessment methods and esults at a test site (Apulia, southen Italy). Natual Hazads and Eath System Sciences, vol. 9, pp ,

12 [23] S. S. D. Foste, Fundamental concepts in aquife vulneability, pollution isk and potection stategy. In : TNO Committee on Hydological Reseach, the Hague, Poceedings and Infomation, Ed. by: van Duijvenbooden, W. and van Waegeningh, G. H., vol. 38, pp , [24] R. Zhang, J. D. Hamelinck, S. P. Gloss, and L. Munn, Detemination of nonpoint-souce pollution using GIS and numeical models. Jounal of Envionmental Quality, vol. 25, pp , [25] A. J. Tesoieo, E. L. Inkpen, and F. D. Voss, Assessing goundate vulneability using logistic egession. Poceedings fo the Souce Wate Assessment and Potection 98 Confeence, Dallas, TX, pp , [26] J. E. Babash, and E. A. Resek, Pesticides in goundate: Distibution, tends, and govening factos. Pesticides in the Hydologic System Seies, vol. 2, p. 590, [27] N. Almasi Mohammad, Assessment of intinsic vulneability to contamination fo Gaza coastal aquife, Palestine. Jounal of Envionmental Management, vol. 88, pp , [28] K. Bekhoff, Spatially explicit goundate vulneability assessment to suppot the implementation of the Wate Fameok Diective a pactical appoach ith stakeholdes. Hydol. Eath Syst. Sci., vol. 12, pp , [29] A. Rahman, A GIS based DRASTIC model fo assessing goundate vulneability in shallo aquife in Aligah, India, Applied Geogaphy, vol. 28, pp , [30] H. Massone, M. Q. Londoño, and D. Matínez, Enhanced goundate vulneability assessment in geological homogeneous aeas: A case study fom the Agentine Pampas. Hydogeol J. vol. 18, pp , [31] K. Kansiiikul, F. S. Singhaajaapan, R. Mackay, T. Ramingong, and P. Wongponchai, Vulneability Assessment Of Goundate Resouces In The Lampang Basin Of Nothen Thailand. Jounal of Envionmental Hydology, vol. 12, iss. 23, pp. 1-15, [32] Y. J. Kim, and S. Hamm, Assessment of the potential fo goundate contamination using the DRASTIC/EGIS technique, Cheongju aea, South Koea. Hydogeology Jounal, vol. 7, pp , [33] S. Secunda, M. Collin, and A. J. Mellou, Goundate vulneability assessment using a composite model combining DRASTIC ith extensive land use in Isael. Jounal of Envionmental Management, vol. 54, pp , [34] J. M. Vias, B. Andeo, M. J. Peles, and F. Caasco, A compaative study of fou schemes fo goundate vulneability mapping in a diffuse flo cabonate aquife unde Mediteanean climatic conditions. Envion Geol, vol. 47, pp , [35] Bosig Kaolin, T. Geye, A. Subah, and M. Saute, Tavel time based appoach fo the assessment of vulneability of kast goundate: The Tansit Time Method. Envion Geol, vol. 54, pp , [36] J. P. Lobo Feeia, and M. Oliveia Manuel, Goundate vulneability assessment in Potugal. Geofísica Intenacional, vol. 43, pp , [37] J. Noui, S. Malmasi, The ole of goundate vulneability in uban development planning. Ameican Jounal of Env. Sc., vol. 1, pp , [38] Helinge J R, and Antonio Pedo Vieo, Goundate vulneability assessment in coastal plain of Rio Gande do Sul State, Bazil, using dastic and adsoption capacity of soils. Envion Geol, vol. 52, pp , [39] R. A. N. Al-Adamat, I. D. L. Foste, and S. M. J. Baban, Goundate vulneability and isk mapping fo the basaltic aquife of the Azaq basin of Jodan using GIS, emote sensing and DRASTIC. Applied Geogaphy, vol. 23, pp , [40] M. C. Ana, Pem, and V. B. Rao (2003) Evaluation of goundate potential of Musi Rive catchment using DRASTIC index model. In: Venkatesha B R, Ram M K, Saala C S, Raju C (Eds.), Hydology and ateshed management. Poceedings of the Intenational Confeence 18 20, 2002, B S Publishes, Hydeabad. [41] Chandashekha H, Adiga S, Lakshminaayana V, Jagdeesha C J, Nataaju C (1999) A case study using the model DRASTIC fo assessment of goundate pollution potential. In Poceedings of the ISRS national symposium on emote sensing applications fo natual esouces, June 19 21, Bangaloe. [42] B. Dixon, Goundate vulneability mapping: A GIS and fuzzy ule based integated tool. Applied Geogaphy, vol. 25, pp , [43] T. L. Saaty, Axiomatic foundation of the analytic hieachy pocess. Management Science, vol. 32, pp , [44] B. G. Mekin (1979) Goup Choice. John Wiley & Sons, NY. [45] T. L. Saaty (1980) The analytic hieachy pocess. McGa Hill, Ne Yok. [46] T. L. Saaty, Ho to make a decision: The analytic hieachy pocess. Intefaces, vol. 24, pp ,