基于地下水流数值模型的改进DRASTIC方法

地下水脆弱性评价作为地下水资源保护和地下水开发利用规划的一个重要工具,被广泛的应用于实际工作中。尝试利用地下水数值模型为改进的DRASTIC方法提供数据支持,并以北京市平原区为例探讨地下水脆弱性评价方法。评价结果与传统方法在高值区和低值区具有很好的对应性,而基于模型的方法在地下水水位计算、含水层介质和水力传导系数确定上较传统方法更具优势,如地下水位的计算上较传统方法更为客观地体现含水介质对地下水运动的影响,且能够方便地获得模拟期内任意时间的流场数据;经由模型调试后的含水层参数数据,较传统方法更为准确。评价结果分区之间的变化较传统方法更为平滑,更符合水文地质条件渐变的特性。     

A GIS-based DRASTIC model for assessing groundwater vulnerability in the Ordos Plateau, China

Groundwater plays a key role in arid regions as the majority of water is supplied by it. Groundwater pollution is a major issue, because it is susceptible to contamination from land use and other anthropogenic impacts. A study was carried out to build a vulnerability map for the Ordos Plateau using the DRASTIC model in a GIS environment. The map was designed to show the areas of the highest potential for groundwater pollution based on hydrogeological conditions. Seven environmental parameters, such as depth to water table, net recharge, aquifer media, soil media, topography, impact of the vadose zone media, and hydraulic conductivity of the aquifer, were incorporated into the DRASTIC model and GIS was used to create a groundwater vulnerability map by overlaying the available data. The results of this study show that 24.8 % of the study area has high pollution potential, 24.2 % has moderate pollution potential, 19.7 % has low pollution potential, and the remaining 31.3 % of the area has no risk of groundwater pollution. The regional distribution of nitrate is well correlated with the DRASTIC vulnerability index. In contrast to this, although the DRASTIC model indicated that the western part had no risk, nitrate concentrations were higher in some of these areas. In particular, higher nitrate concentrations were recorded along river valleys and around lakes, such as the Mulin River valley. This is mainly caused by the intensive agricultural development and favorable conditions for recharge along river valleys.     

A GIS-based DRASTIC model for assessing shallow groundwater vulnerability in the Zhangye Basin,northwestern China

Groundwater vulnerability is a cornerstone in evaluating the risk of groundwater contamination and developing management options to preserve the quality of groundwater. Based on the professional model (DRASTIC model) and geographical information system (GIS) techniques, this paper carries out the shallow groundwater vulnerability assessment in the Zhangye Basin. The DRASTIC model uses seven environmental parameters (depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, and hydraulic conductivity) to characterize the hydrogeological setting and evaluate aquifer vulnerability. According to the results of the shallow groundwater vulnerability assessment, the Zhangye Basin can be divided into three zones: low groundwater vulnerability risk zone (risk index <120); middle groundwater vulnerability risk zone (risk indexes 120–140) and high risk zone (risk index >140). Under the natural conditions, the middle and high groundwater vulnerability risk zones of the Zhangye Basin are mainly located in the groundwater recharge zones and the important cities. The high, middle and low groundwater vulnerability risk zones of the Zhangye Basin cover around 17, 21 and 62% of study area, respectively.     

Evaluation of groundwater vulnerability to pollution using DRASTIC framework and GIS

Groundwater management has a prominent role in the world especially in arid and semi-arid areas which have a shortage of water, and due to this serious problem, many researchers work on that for prevention and managing the water recourses to conserve and monitor sources. DRASTIC index can be put forward for estimating of groundwater vulnerability to such pollution. The main purpose of using the groundwater vulnerability model is to map groundwater susceptibility to pollution in different areas. However, this method has been used in various areas without modification, disregarding the effects of pollution type and characteristics. Thus, this technique must be standardized and approved for Kerman plain. Vulnerability evaluation to explain areas that are more vulnerable to contamination from anthropogenic sources has become a prominent element for land use planning and tangible resource management. This contribution aims at evaluating groundwater vulnerability by applying the DRASTIC index as well as employ sensitivity analyses to evaluate the comparative prominent of the model parameters for groundwater vulnerability in Kerman plain in the southeastern part of Iran. Moreover, the potential of vulnerability to pollution is more accurately assessed by optimizing the weights of the DRASTIC parameters with the single-parameter sensitivity analysis (SPSA). The new weights were calculated. The result of the study revealed that the DRASTIC-Sensitivity analysis exhibit more efficiently than the traditional method for a nonpoint source pollution. Observation of ultimate nitrate showed the result of DRASTIC-SPSA has more accuracy. The GIS method offers an efficient environment for carrying out assessments and greater capabilities for dealing with a huge quantity of spatial data.     

地下水易污性评价方法——DRASTIC指标体系

本文较详细地介绍了目前欧美国家在地下水易污性评价中所广泛采用的ＤＲＡＳＴＩＣ指标体系方法,对其中所含的地下水埋深,含水层的净补给,岩性,土壤类型,渗流区介质,水力传导系数７个参数的评分以及在评分过程中所应注意的问题进行了具体的阐述,最后简要介绍了ＤＲＡＳＴＩＣ易污性指标体系法在大连沿海地区地下水易污性评价中应用的情况,实际应用表明该方法可适用于我国广大地区的地下水易污性评价工作。     

DRASTIC评价模型在台州市浅层地下水脆弱性评价中的应用

本文介绍了DRASTIC评价体系在台州市浅层地下水的脆弱性评价中的应用.根据台州市的地质背景、水文地质条件等,对DRASTIC评价指标进行改进,选择了地下水埋深等4个参数作为研究区地下水脆弱性评价因子,建立了台州市浅层地下水脆弱性评价模型.结合GIS技术对该地区的地下水脆弱性进行了评价,编制了地下水脆弱性评价图.综合评价的结果表明改进的DScTI评价模型能合理的反映台州市浅层地下水环境脆弱性的高低.     

Assessing groundwater vulnerability using GIS-based DRASTIC model for Ahmedabad district,India

The present research aims to derive the intrinsic vulnerability of groundwater against contamination using the GIS platform. The study applies DRASTIC model for Ahmedabad district in Gujarat, India. The model uses parameters like depth, recharge, aquifer, soil, topography, vadose zone and hydraulic conductivity, which depict the hydrogeology of the area. The research demonstrates that northern part of district with 46.4% of area is under low vulnerability, the central and southern parts with 48.4% of the area are under moderate vulnerability, while 5.2% of area in the south-east of district is under high vulnerability. It is observed from the study that lower vulnerability in northern part may be mostly due to the greater depth of vadose zone, deeper water tables and alluvial aquifer system with minor clay lenses. The moderate and high vulnerability in central and southern parts of study area may be due to lesser depth to water tables, smaller vadose zone depths, unconfined to semi-confined alluvial aquifer system and greater amount of recharge due to irrigation practices. Further, the map removal and single-parameter sensitivity analysis indicate that groundwater vulnerability index has higher influence of vadose zone, recharge, depth and aquifer parameters for the given study area. The research also contributes to validating the existence of higher concentrations of contaminants/indicators like electrical conductivity, chloride, total dissolved solids, sulphate, nitrate, calcium, sodium and magnesium with respect to groundwater vulnerability status in the study area. The contaminants/indicators exceeding the prescribed limits for drinking water as per Indian Standard 10500 (1991) were mostly found in areas under moderate and high vulnerability. Finally, the research successfully delineates the groundwater vulnerability in the region which can aid land-use policies and norms for activities related to recharge and seepage with respect to existing status of groundwater vulnerability and its quality.     

The DRASTIC-Sg model: an extension to the DRASTIC approach for mapping groundwater vulnerability in aquifers subject to differential land subsidence,with application to Mexico City

Mexico City relies on groundwater for most of its domestic supply. Over the years, intensive pumping has led to significant drawdowns and, subsequently, to severe land subsidence. Tensile cracks have also developed or reactivated as a result. All such processes cause damage to urban infrastructure, increasing the risk of spills and favoring contaminant propagation into the aquifer. The effects of ground deformation are frequently ignored in groundwater vulnerability studies, but can be relevant in subsiding cities. This report presents an extension to the DRASTIC methodology, named DRASTIC-Sg, which focuses on evaluating groundwater vulnerability in urban aquifers affected by differential subsidence. A subsidence parameter is developed to represent the ground deformation gradient (Sg), and then used to depict areas where damage risk to urban infrastructure is higher due to fracture propagation. Space-geodetic SqueeSAR data and global positioning system (GPS) validation were used to evaluate subsidence rates and gradients, integrating hydrogeological and geomechanical variables into a GIS environment. Results show that classic DRASTIC approaches may underestimate groundwater vulnerability in settings such as the one at hand. Hence, it is concluded that the Sg parameter is a welcome contribution to develop reliable vulnerability assessments in subsiding basins.     

Assessment of groundwater vulnerability to pollution in Dire Dawa,Ethiopia using DRASTIC

Assessment of groundwater vulnerability to pollution is an effective tool for the delineation of groundwater protection zones. DRASTIC approach was used to determine vulnerability zones in Dire Dawa groundwater basin, a semiarid region of Ethiopia. Maps of the seven DRASTIC parameters were prepared. GIS-ArcView was used for mapping and performing weighted-overlay analysis. The result of the analysis indicated that eastern part of the study area, in which Dire Dawa town is located, is highly vulnerable. A low aquifer vulnerability class was determined for the western portion of the study area as a result of greater groundwater depths, higher relative soil-clay content, and relatively low recharge rates for this area. The area between the two zones is of medium vulnerability. Observed nitrate concentrations in boreholes are in accordance with the vulnerability map. Some of the boreholes in the Sabian well field (Dire Dawa area) already deliver groundwater with nitrate levels significantly exceeding health standards set by the World Health Organization, while boreholes in the western part (low vulnerability zone) contain almost no nitrate. The result of this study is useful for risk assessments and for the development of effective groundwater management strategies for this region and others like it.     

改进的DRASTIC模型在地下水易污染性模糊评价中的应用

为了有效避免地下水系统遭受污染,保护地下水资源,采用改进的DRASTIC模型对地下水易污染性进行了评价.鉴于DRASTIC模型的诸多缺陷,将模糊综合评价方法运用到模型中,构建了各评价指标于各个级别的最优相对隶属度矩阵;引用语气算子确定指标权重,计算出了研究区样本集的级别特征值向量.将样本的易污染性进行排序,用研究区样段的水质评价结果进行了验证,结果证明,易污染性程度越高的地区综合评价水质越差;为进一步验证评价方法的真实性,将易污染性排序结果与传统DRASTIC法评价排序结果进行对比,两种方法排序一致.可见,本次改进的模型在克服了DRASTIC的诸多缺陷的同时,使得计算结果真实、可靠,且更加体现了计算过程的科学性与合理性.     

An extension to the DRASTIC model to assess groundwater vulnerability to pollution: application to the Haouz aquifer of Marrakech (Morocco)

An extension to the DRASTIC model is proposed in order to assess aquifer vulnerability to pollution. In contrast to the DRASTIC model, which considers the unsaturated and saturated zones together and computes a global intrinsic vulnerability index, the suggested approach discriminates between the aquifer vertical vulnerability (a concept related to the pollutant percolation) and the groundwater susceptibility (a concept that depends on the behaviour and uses of the groundwater). This approach is applied to the Haouz aquifer (Morocco) that supplies water to the Marrakech area. This aquifer is widely overexploited and there is evidence that the groundwater quality is threatened by various sources of pollution. Evaluation of the vertical vulnerability indicates that the aquifer mainly presents a moderate-to-weak vertical vulnerability. The zones potentially most favourable to pollutant percolation are mainly located in Central Haouz, along or near the surface wadis. The aquifer susceptibility is high in places located near the N’Fis, Baaja and Issil wadis. Everywhere else, low-to-moderate susceptibility is observed. This new approach therefore enables areas of vertical vulnerability and areas of susceptibility to be delineated separately. As a result, it constitutes a valuable decision-making tool for optimising the management of aquifer water resources and land-use planning.     

溶地下水脆弱性评价“二元法”及其在重庆金佛山的应用

岩溶地下水脆弱性评价是基于保护岩溶含水层从而有效地管理和利用地下水提出的有效方法和手段。我国西南岩溶区极大多数地区缺少应有的地下水保护带,地下水比较容易受到污染。本文论述了一种脆弱性的评价的简单方法— —基于径流特征和覆盖层厚度的二元法,并利用该法对重庆金佛山典型岩溶区进行了地下水脆弱性评价。结果表明,药池坝洼地和生态石林区脆弱性较高。究其原因,尽管药池坝洼地底部土壤层覆盖较厚,但存在地表径流集中排向落水洞,生态石林分布区地表裂隙、溶沟发育,可直接接受雨水入渗,因而污染物极易通过降雨和地表径流过程进入含水层。这一方法输入数据量小,对岩溶含水层普遍适用,为地下水资源可持续利用和土地利用管理提供了强有力的工具。      

GIS-based DRASTIC model for groundwater vulnerability and pollution risk assessment in the Peshawar District,Pakistan

Groundwater is the most economic natural source of drinking in urban and rural areas which are degraded due to high population growth and increased industrial development. We applied a GIS-based DRASTIC model in a populated urban area of Pakistan (Peshawar) to assess groundwater vulnerability to pollution. Six input parameters—depth to phreatic/groundwater level, groundwater recharge, aquifer material, soil type, slope, and hydraulic conductivity—were used in the model to generate the groundwater vulnerable zones. Each parameter was divided into different ranges or media types, and ratings R?=?1?–?10 were assigned to each factor where 1 represented the very low impact on pollution potential and 10 represented very high impact. Weight multipliers W?=?1?–?5 were also used to balance and enhance the importance of each factor. The DRASTIC model scores obtained varied from 47 to 147, which were divided into three different zones: low, moderate, and high vulnerability to pollution. The final results indicate that about 31.22, 39.50, and 29.27% of the total area are under low, moderate, and high vulnerable zones, respectively. Our method presents a very simple and robust way to assess groundwater vulnerability to pollution and helps the decision-makers to select appropriate landfill sites for waste disposals, and manage groundwater pollution problems efficiently.     

Transport and fate of chloride from road salt within a mixed urban and agricultural watershed in Illinois (USA): assessing the influence of chloride application rates

In a typical winter season, approximately 471,000 tons of road salt are deposited along roadways in Illinois, USA. An estimated 45% of the deposited road salt will infiltrate through the soils and into shallow aquifers. Transported through shallow aquifers, chloride associated with the road salts has the potential to reside within groundwater for years based on the pathway, the geologic material, and the recharge rate of the aquifer system. Utilizing MODFLOW and MT3D, simulations employing various road-salt application rates were conducted to assess the net accumulation of chloride and the residence times of chloride in an agriculture-dominated watershed that originates in an urban area. A positive-linear relationship was observed between the application rate of chloride and both the maximum chloride concentration and total mass accumulated within the watershed. Simulated annual recharge rates along impacted surfaces ranged from 1,000 to 10,000 mg/L. After 60 years of application, simulated chloride concentrations in groundwater ranged from 197 to 1,900 mg/L. For all application rates, chloride concentrations within the groundwater rose at an annual rate of >3 mg/L. While concentrations increase throughout the system, the majority of chloride accumulation occurs near the roads and the urban areas. Model simulations reveal a positive relationship between application rate and residence time of chloride (1,123–1,288 days based on application rate). The models indicate that continued accumulation of chloride in shallow aquifers can be expected, and methods that apply less chloride effectively need to be examined.

     

Development of a GIS-based catastrophe theory model (modified DRASTIC model) for groundwater vulnerability assessment

This study developed a new paradigm for groundwater vulnerability assessment by modifying the standard DRASTIC index (DI) model based on catastrophe theory. The developed paradigm was called the catastrophe theory-based DI (CDI) model. The proposed model was applied to assess groundwater vulnerability to pollution index (GVPI) in Perak Province, Malaysia. The area vulnerability index was modeled by considering the DRASTIC multiple vulnerability causative factors (VCFs) obtained from different data sources. The weights and ranking of the VCFs were computed by using the inner fuzzy membership mechanism of the CDI model. The estimated vulnerability index values of the CDI model were processed in a geographic information system (GIS) environment to produce a catastrophe theory–DRASTIC groundwater vulnerability to pollution index (CDGVPI) map, which demarcated the area into five vulnerability zones. The produced CDGVPI map was validated by applying the water quality status–vulnerability zone relationship (WVR) approach and the relative operating characteristic (ROC) curve method. The performance of the developed CDI model was compared with that of the standard DI model. The validation results of the WVR approach exhibits 89.29% prediction accuracy for the CDI model compared with 75% for the DI model. Meanwhile, the ROC validation results for the CDI and DI models are 88.8% and 78%, respectively. The GIS-based CDI model demonstrated better performance than the DI model. The GVPI maps produced in this study can be used for precise decision making process in environmental planning and groundwater management.     

Estimating groundwater vulnerability to pollution using a modified DRASTIC model in the Kerman agricultural area,Iran

Groundwater contamination from intensive fertilizer application affects conservation areas in a plain. The DRASTIC model can be applied in the evaluation of groundwater vulnerability to such pollution. The main purpose of using the DRASTIC model is to map groundwater susceptibility to pollution in different areas. However, this method has been used in various areas without modification, thereby disregarding the effects of pollution types and their characteristics. Thus, this technique must be standardized and be approved for applications in aquifers and particular types of pollution. In this study, the potential for the more accurate assessment of vulnerability to pollution is achieved by correcting the rates of the DRASTIC parameters. The new rates were calculated by identifying the relationships among the parameters with respect to the nitrate concentration in groundwater. The methodology was implemented in the Kerman plain in the southeastern region of Iran. The nitrate concentration in water from underground wells was tested and analyzed in 27 different locations. The measured nitrate concentrations were used to associate and correlate the pollution in the aquifer to the DRASTIC index. The Wilcoxon rank-sum nonparametric statistical test was applied to determine the relationship between the index and the measured pollution in Kerman plain. Also, the weights of the DRASTIC parameters were modified through the sensitivity analysis. Subsequently, the rates and weights were computed. The results of the study revealed that the modified DRASTIC model performs more efficiently than the traditional method for nonpoint source pollution, particularly in agricultural areas. The regression coefficients showed that the relationship between the vulnerability index and the nitrate concentration was 82 % after modification and 44 % before modification. This comparison indicated that the results of the modified DRASTIC of this region are better than those of the original method.     

Comparison of DRASTIC and DC resistivity modeling for assessing aquifer vulnerability in the central Nile Delta,Egypt

DRASTIC indexing and integrated electrical conductivity (IEC) modeling are approaches for assessing aquifer vulnerability to surface pollution. DRASTIC indexing is more common, but IEC modeling is faster and more cost-effective because it requires less data and fewer processing steps. This study aimed to compare DRASTIC indexing with IEC modeling to determine whether the latter is sufficient on its own. Both approaches are utilized to determine zones vulnerable to groundwater pollution in the Nile Delta. Hence, assessing the nature and degree of risk are important for realizing effective measures toward damage minimization. For DRASTIC indexing, hydrogeological factors such as depth to aquifer, recharge rate, aquifer media, soil permeability, topography, impact of the vadose zone, and hydraulic conductivity were combined in a geographical information system environment for assessing the aquifer vulnerability. For IEC modeling, DC resistivity data were collected from 36 surface sounding points to cover the entire area and used to estimate the IEC index. Additionally, the vulnerable zones identified by both approaches were tested using a local-scale resistivity survey in the form of 1D and 2D resistivity imaging to determine the permeable pathways in the vadose zone. A correlation of 0.82 was obtained between the DRASTIC indexing and IEC modeling results. For additional benefit, the obtained DRASTIC and IEC models were used together to develop a vulnerability map. This map showed a very high vulnerability zone, a high-vulnerability zone, and moderate- and low-vulnerability zones constituting 19.89, 41, 27, and 12%, respectively, of the study area. Identifying where groundwater is more vulnerable to pollution enables more effective protection and management of groundwater resources in vulnerable areas.     

Optimization of the DRASTIC method for groundwater vulnerability assessment via the use of simple statistical methods and GIS

The assessment of groundwater vulnerability to pollution has proved to be an effective tool for the delineation of protection zones in areas affected by groundwater contamination due to intensive fertilizer applications. By modifying and optimizing the well known and widely used DRASTIC model it was possible to predict the intrinsic vulnerability to pollution as well as the groundwater pollution risk more accurately. This method incorporated the use of simple statistical and geostatistical techniques for the revision of the factor ratings and weightings of all the DRASTIC parameters under a GIS environment. The criterion for these modifications was the correlation coefficient of each parameter with the nitrates concentration in groundwater. On the basis of their statistical significance, some parameters were subtracted from the DRASTIC equation, while land use was considered as an additional DRASTIC parameter. Following the above-mentioned modifications, the correlation coefficient between groundwater pollution risk and nitrates concentration was considerably improved and rose to 33% higher than the original method. The model was applied to a part of Trifilia province, Greece, which is considered to be a typical Mediterranean region with readily available hydrogeological and hydrochemical data.

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Resumen La evaluación de vulnerabilidad del agua subterránea a la contaminación ha demostrado ser una herramienta efectiva para la delimitación de zonas de protección en áreas afectadas por contaminación de aguas subterráneas debido a aplicaciones intensivas de fertilizantes. Mediante la modificación y optimización del bien conocido y ampliamente utilizado modelo DRASTIC fue posible predecir la vulnerabilidad intrínseca a la contaminación así como el riesgo a la contaminación del agua subterránea con mayor precisión. Este método incorporó el uso de técnicas estadísticas y geoestadísticas simples para la revisión del pesaje y establecimiento de rangos de factores de todos los parámetros DRASTIC bajo un ambiente SIG. El criterio para estas modificaciones fue el coeficiente de correlación de cada parámetro con las concentraciones de nitraros en agua subterránea. En base al grado significativo estadístico algunos parámetros fueros sustraídos de la ecuación DRASTIC, mientras que se consideró el uso de la tierra como un parámetro adicional de DRASTIC. Siguiendo las modificaciones antes mencionadas se mejoró considerablemente el coeficiente de correlación entre el riesgo a la contaminación del agua subterránea y las concentraciones de nitratos incrementando en 33% su valor en relación al método original. El modelo se aplicó en una parte de la provincia Trifilia, Grecia, la cual se considera ser una región Mediterránea típica con datos hidroquímicos e hidrogeológicos fácilmente disponibles.

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Résumé L’évaluation de la vulnérabilité des eaux souterraines à la pollution a montré qu’elle est un outil efficace pour délimiter les zones de protection dans les zones affectées par la contamination des eaux souterraines due à l’utilisation intensive de fertilisants. En modifiant et optimisant le modèle DRASTIC, bien connu et souvent utilisé, il a été possible de prédire la vulnérabilité intrinsèque à la pollution, et de définir plus précisément le risque de pollution. Cette méthode incorpore l’utilisation de simples techniques statistiques et géostatistiques, pour la révision des facteurs d’estimation et de pondération de tous les paramètres de DRASTIC sous S.I.G. Le critère de ces modifications était le coefficient de corrélation de chaque paramètre avec la concentration en nitrates dans les eaux souterraines. Sur la base de leur signification statistique, certains paramètres ont été soustraits de l’équation DRASTIC. Suivant les modifications mentionnées ci-dessus, le coefficient de corrélation entre les concentrations en nitrate et le risque de pollution des eaux souterraines a été considérablement amélioré de 33% par rapport à la méthode originale. Le modèle a été appliqué sur une partie de la province de Trifilia en Grèce, qui est considérée comme une région typiquement méditerranéenne avec des données hydrogéologiques et hydrochimiques aisément accessibles.

     

Assessing groundwater vulnerability and its inconsistency with groundwater quality,based on a modified DRASTIC model: a case study in Chaoyang District of Beijing City

Depth to water, net recharge, aquifer media, soil media, topography, impact of the vadose zone media, and hydraulic conductivity of the aquifer (DRASTIC) model based on a geographic information system (GIS) is the most widely adopted model for the evaluation of groundwater vulnerability. However, the model had its own disadvantages in various aspects. In this work, several methods and the technologies have been introduced to improve on the traditional model. The type of the aquifer was replaced by the thickness of the aquifer, and the index of topography was removed. The indexes of the exploitation of the groundwater and the type of land use that reflected the special vulnerability were added to the system. Furthermore, considering the wideness of the study area, the fixed weights in the DRASTIC model were not suitable. An analytic hierarchy process (AHP) method and an entropy weight (Ew) method were introduced to calculate the weights of parameters. Then, the Spearman Rho correlation coefficients between IVI and the Nemerow synthetical pollution index (NI) of the groundwater quality were significantly improved, after the four steps of modification. The level differences with little gaps between Nemerow comprehensive pollution indexes and groundwater vulnerability occupied the proportion of the area from 75.68 to 84.04%, and finally, a single-parameter sensitivity analysis for the two models was used to compute the effective weights of these parameters. By comparison, the DRMSICEL model seems to perform better than the DRASTIC model in the study area. And the results show discrepancies between the vulnerability indices and groundwater quality as indicated by existence of vulnerable areas with bad water quality and vice versa.