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1.
The present work attempts to interpret the groundwater vulnerability of the Melaka State in peninsular Malaysia. The state of groundwater pollution in Melaka is a critical issue particularly in respect of the increasing population, and tourism industry as well as the agricultural, industrial and commercial development. Focusing on this issue, the study illustrates the groundwater vulnerability map for the Melaka State using the DRASTIC model together with remote sensing and geographic information system (GIS). The data which correspond to the seven parameters of the model were collected and converted into thematic maps by GIS. Seven thematic maps defining the depth to water level, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity were generated to develop the DRASTIC map. In addition, this map was integrated with a land use map for generating the risk map to assess the effect of land use activities on the groundwater vulnerability. Three types of vulnerability zones were assigned for both DRASTIC map and risk map, namely, high, moderate and low. The DRASTIC map illustrates that an area of 11.02 % is low vulnerability, 61.53 % moderate vulnerability and 23.45 % high vulnerability, whereas the risk map indicates that 14.40 % of the area is low vulnerability, 47.34 % moderate vulnerability and 38.26 % high vulnerability in the study area. The most vulnerability area exists around Melaka, Jasin and Alor Gajah cities of the Melaka State.  相似文献   

2.
The protection and preservation of groundwater resources are compulsory, particularly in the arid and semiarid countries where the waters are scarce. The effects of increasing urbanization, economic development, and agricultural activities, along with the erratic and scarce rainfall, contribute to the quantitative and qualitative deterioration of these resources. This paper attempts to produce groundwater vulnerability and risk maps for the Angad transboundary aquifer using DRASTIC model. The data which correspond to the seven parameters of the model were collected and converted to thematic maps in Geographic Information System environment. The modified DRASTIC map, which is the summation of the DRASTIC index and the network fractures maps, shows two degreed of vulnerability: medium and high. This map is then integrated with a land use map to assess the potential risk of groundwater to pollution in the Angad transboundary aquifer. There are three risk zones that are identified: moderate, high, and very high.  相似文献   

3.
Groundwater is a very important resource across Ismailia area as it is used in domestic, agricultural, and industrial purposes. This makes it absolutely necessary that the effects of land use change on groundwater resources are considered when making land use decisions. Careful monitoring of groundwater resource helps minimize the contamination of this resource. This study developed a GIS-based model to assess groundwater contamination in the West Ismailia area based on its hydrochemical characteristics. The model incorporated five different factors which are standardized to a common evaluation scale. The produced factor maps include the depth to the water table, the potential recharge, the soil type, the topography, and the thickness of saturation. These maps are combined in ERDAS Imagine, ARC INFO, and ARC GIS software using geostatistics and a weighted overlay process to produce the final groundwater potential risk map. The model output is then used to determine the vulnerability of groundwater to contamination by domestic, agricultural, and industrial sources. The produced risk maps are then combined with the groundwater contamination potentiality map using an arithmetic overlay in order to identify areas which were vulnerable to contamination. The results of this study revealed that the groundwater is highly vulnerable to contamination that may result from the inappropriate application of agrichemicals and domestic and industrial activities. The produced integrated potential contamination maps are very useful tools for a decision maker concerned with groundwater protection and development.  相似文献   

4.
Increasing pressure on water resources worldwide has resulted in groundwater contamination, and thus the deterioration of the groundwater resources and a threat to the public health. Risk mapping of groundwater contamination is an important tool for groundwater protection, land use management, and public health. This study presents a new approach for groundwater contamination risk mapping, based on hydrogeological setting, land use, contamination load, and groundwater modelling. The risk map is a product of probability of contamination and impact. This approach was applied on the Gaza Strip area in Palestine as a case study. A spatial analyst tool within Geographical Information System (GIS) was used to interpolate and manipulate data to develop GIS maps of vulnerability, land use, and contamination impact. A groundwater flow model for the area of study was also used to track the flow and to delineate the capture zones of public wells. The results show that areas of highest contamination risk occur in the southern cities of Khan Yunis and Rafah. The majority of public wells are located in an intermediate risk zone and four wells are in a high risk zone.  相似文献   

5.
Groundwater vulnerability assessments calculate the sensitivity of quality of groundwater to an imposed contaminant load which is essential element of the aquifer management plans. Seventy five groundwater samples have been analyzed for different chemical parameters to understand the groundwater quality of the lower Varuna river basin, Uttar Pradesh, India. The intrinsic groundwater vulnerability map of the lower Varuna catchment area in the north of the city of Varanasi (India) shows a high dependency on the depth to groundwater. The topmost layer of alluvial silty clay, protects the groundwater against contamination in this urban area, but the retention time in the unsaturated zone can be estimated to several months only. The input dataset is very sparse i.e. groundwater levels were measured twice (pre- and post-monsoon 2009) and the geological map shows only alluvium as the outcrop. Several boreholes in this area show, that the alluvium has a thickness of about 4 m and below that are fine grained sands. The surface information does not allow the development of a risk map since land use changes very fast and contamination areas can not be identified accurately. The vulnerability maps developed in this study have become important tools for environmental planning and predictive management of the groundwater resources in the fast urbanizing region in the Varanasi area.  相似文献   

6.
Groundwater vulnerability and risk mapping is a relatively new scientific approach for facilitating planning and decision making processes in order to protect this valuable resource. Pan European methodology for aquifers vulnerability has recently been developed by assessing all the existing relevant techniques and emphasizing on karstic environments. In the particular study, state-of-the-art methods and tools have been implemented such as remote sensing, isotopic investigations and GIS to map the groundwater vulnerability and pollution risk in a geologically complex area of W. Greece. The updated land use map has been developed from a Landsat 7+TM image elaborated with image analysis software, while the detailed hydrogeologic properties of the area have been recorded with an intensive isotopic study. The local groundwater vulnerability map has been produced following the aforementioned Pan European method, in a GIS environment while the risk map, which was the final product of the study, has been developed after combining the vulnerability and the land use maps. The results indicated that the areas comprised of highly tectonized calcareous formations represented high vulnerability and risk zones while forested areas away from the karstic aquifer illustrated moderate to low vulnerability. Moreover, human activities increase the pollution risk in lowland areas consisting of sedimentary deposits that have been classified as moderate vulnerability. The particular methodology operated efficiently in this study and due to its accuracy and relatively easy implementation can be used as a decision support tool for local authorities.  相似文献   

7.
GIS Techniques for Mapping Groundwater Contamination Risk   总被引：11，自引：0，他引：11  
Ducci  Daniela 《Natural Hazards》1999,20(2-3):279-294
The groundwater contamination risk map of a samplealluvial area was produced by using the IlwisGeographical Information System (GIS) to construct andto overlay thematic maps. The risk map has beenderived from the vulnerability map, the hazard map,where the potential contaminating sources wereidentified, and the socio-economic value of thegroundwater resource, represented by the wells. Thegroundwater quality map allowed thereliability of hazard and risk maps to be tested.The final map shows interesting results and stressesthe need for the GIS to test and improve on thegroundwater contamination risk assessment methods.  相似文献   

8.
A DRASTIC-model method based on a geographic information system (GIS) was used to study groundwater vulnerability in Egirdir Lake basin (Isparta, Turkey), an alluvial area that has suffered agricultural pollution. ‘Lineament’ and ‘land use’ were added to the DRASTIC parameters, and an analytic hierarchy process (AHP) method determined the rating coefficients of each parameter. The effect of lineament and land-use parameters on the resulting vulnerability maps was determined with a single-parameter sensitivity analysis. Of the DRASTIC parameters, land use affects the aquifer vulnerability map most and lineament affects it least, after topography. A simple linear regression analysis assessed the statistical relation between groundwater nitrate concentration and the aquifer vulnerability areas; the highest R 2 value was obtained with the modified-DRASTIC-AHP method. The DRASTIC vulnerability map shows that only the shoreline of Egirdir Lake and the alluvium units have high contamination potential. In this respect, the modified DRASTIC vulnerability map is quite similar. According to the modified-DRASTIC-AHP method, the lakeshore areas of Senirkent-Uluborlu and Hoyran plains, and all of the Yalvaç-Gelendost plain, have high contamination potential. Analyses confirm that groundwater nitrate content is high in these areas. By comparison, the modified-DRASTIC-AHP method has provided more valid results.  相似文献   

9.
A detailed hydrogeological and hydrochemical study was carried out in Yamuna-Krishni sub-basin which is a part of the vast central Ganga plain. Groundwater is the major source of water supply for agricultural, domestic and industrial uses. The excess use of groundwater has resulted in depletion of water levels. The groundwater quality, too, has deteriorated in areas dominated by industrial activity. This has led to the preparation of a groundwater vulnerability map in relation to contamination. Groundwater vulnerability maps are valuable derivative maps that show, quantitatively or qualitatively, certain characteristics of the sub-surface environment that determine vulnerability of groundwater to contamination. The modified DRASTIC method was used to prepare vulnerability map. The parameters like depth to water, net recharge, aquifer media, soil media, impact of vadose zone, hydraulic conductivity and land use pattern, owing to its bearing on groundwater regime, were considered to prepare vulnerability map. The vulnerability index is computed as the sum of the products of weight and rating assigned to each of the input considered as above. The vulnerability index ranges from 140 to 180, and is classified into four classes i.e. 140–150, 150–160, 160–170 and 170–180 corresponding to low, medium, high and very high vulnerability zones respectively. Using this index, a groundwater vulnerability potential map was generated which shows that 7%, 40% and 53% of the study area falls in low, medium and high to very high vulnerability zones respectively. The map, thus generated, can be used as a tool for protection and management of aquifers from contamination.  相似文献   

10.
The use of indices, describing aquifer vulnerability and the risk of groundwater pollution, is a basic tool for the implementation of a sound water management plan, especially in densely populated and intensely cultivated areas. In this study, the groundwater contamination risk of the Caserta Plain (Southern Italy) was assessed through the integration of hazards defined on the basis of the different land uses, of the intrinsic vulnerability calculated by applying the SINTACS model and of the groundwater value evaluated by considering water wells density. In order to evaluate the evolution of the risk of groundwater pollution, the proposed methods were applied in the study area for both 2001 and 2009. The resulting specific vulnerability (SINTACS-L) and the risk (GRA) maps, created in a GIS environment, were validated by the comparison with the nitrate concentration distribution. The application of the proposed approach to the study area highlighted the strengths and weaknesses of each method and, at the same time, showed that their combination can provide an overall view of the threats posed to groundwater resources by the human activities affecting the territory. Considering both the benefits and the issues of the proposed approach, overall, the groundwater risk map is thought to be a robust tool to support water managers in defining future plans for water resources exploitation and land use.  相似文献   

11.
《地学前缘(英文版)》2020,11(5):1805-1819
In Punjab(Pakistan),the increasing population and expansion of land use for agriculture have severely exploited the regional groundwater resources.Intensive pumping has resulted in a rapid decline in the level of the water table as well as its quality.Better management practices and artificial recharge are needed for the development of sustainable groundwater resources.This study proposes a methodology to delineate favorable groundwater potential recharge zones(FPRI) by integrating maps of groundwater potential recharge index(PRI) with the DRASTIC-based groundwater vulnerability index(VI).In order to evaluate both indexes,different thematic layers corresponding to each index were overlaid in ArcGIS.In the overlay analysis,the weights(for various thematic layers) and rating values(for sub-classes) were allocated based on a review of published literature.Both were then normalized and modified using the analytical hierarchical process(AHP) and a frequency ratio model respectively.After evaluating PRI and FPRI,these maps were validated using the area under the curve(AUC) method.The PRI map indicates that 53% of the area assessed exists in very low to low recharge zones,22% in moderate,and 25% in high to excellent potential recharge zones.The VI map indicates that 38% of the area assessed exists in very low to low vulnerability,33% in moderate,and 29% in high to very high vulnerability zones.The FPRI map shows that the central region of Punjab is moderately-to-highly favorable for recharge due to its low vulnerability and high recharge potential.During the validation process,it was found that the AUC estimated with modified weights and rating values was 79% and 67%,for PRI and VI indexes,respectively.The AUC was less when evaluated using original weights and rating values taken from published literature.Maps of favorable groundwater potential recharge zones are helpful for planning and implementation of wells and hydraulic structures in this region.  相似文献   

12.
The Nubian Sandstone Aquifer (NSSA) is the main groundwater resource of the El-Bahariya Oasis, which is located in the middle of the Western Desert of Egypt. This aquifer is composed mainly of continental clastic sediments of sandstone with shale and clay intercalations of saturated thickness ranging between 100 and 1500 m. Vulnerability assessment to delineate areas that are more susceptible to contamination from anthropogenic sources has become an important element for sustainable resources management and land use planning. Accordingly, this research aims to estimate the vulnerability of NSSA by applying the DRASTIC model as well as utilising sensitivity analyses to evaluate the relative importance of the model parameters for aquifer vulnerability in the study area. The main objective is to demonstrate the combined use of the DRASTIC and the GIS techniques as an effective method for groundwater pollution risk assessment, and mapping the areas that are prone to deterioration of groundwater quality and quantity. Based on DRASTIC index (DI) values, a groundwater vulnerability map was produced using the GIS. The aquifer analysis in the study area highlighted the following key points: the northeastern and western parts of the NSSA were dominated by ‘High’ vulnerability classes while the northwestern and southeastern parts were characterised by ‘Medium’ vulnerability classes. The elevated central part of the study area displayed ‘Low’ aquifer vulnerability. The vulnerability map shows a relatively greater risk imposed on the northeastern part of the NSSA due to the larger pollution potential of intensive vegetable cultivation. Depth-to-water, topography and hydraulic conductivity parameters were found to be more effective in assessing aquifer vulnerability.  相似文献   

13.
The area of Thal Doab is located in the Indus Basin and is underlain by a thick alluvial aquifer called the Thal Doab aquifer (TDA). The TDA is undergone intense hydrological stress owing to rapid population growth and excessive groundwater use for livestock and irrigated agricultural land uses. The potential impact of these land uses on groundwater quality was assessed using a DRASTIC model in a Geographic Information System environment. Seven DRASTIC thematic maps were developed at fixed scale and then combined into a groundwater vulnerability map. The resultant vulnerability index values were grouped into four zones as low, moderate, high and very high. The study has established that 76% of the land area that is underlain by the TDA has a high to very high vulnerability to groundwater contamination mainly because of a thin soil profile, a shallow water table and the presence of soils and sediments with high hydraulic conductivity values. In addition, only 2 and 22% of the total area lie in low and moderate vulnerability zones, respectively. The outcomes of this study can be used to improve the sustainability of the groundwater resource through proper land-use management.  相似文献   

14.
The study region comprises the Sidi Bouzid shallow aquifer, which is located in the western part of Central Tunisia. It is mainly occupied by agricultural land with intensive use of chemical fertilizers especially nitrates. For this reason, nitrate measurement was performed in 38 water samples to evaluate and calibrate the obtained models. Several environmental parameters were analyzed using groundwater nitrate concentrations, and different statistical approaches were applied to assess and validate the groundwater vulnerability to nitrate pollution in the Sidi Bouzid shallow aquifer. Multiple linear regression (MLR), analyses of covariance (ANCOVA), and logistic regression (LR) were carried out for studying the nitrate effects on groundwater pollution. Statistical analyses were used to identify major environmental factors that control the groundwater nitrate concentration in this region. Correlation and statistical analyses were conducted to examine the relationship between the nitrate (dependent variable) and various environmental variables (independent variables). All methods show that “groundwater depth” and “land use” parameters are statistically significant at 95% level of confidence. Groundwater vulnerability map was obtained by overlaying these two thematic layers which were obtained in the GIS environment. It shows that the high vulnerability area coincides with the likelihood that nitrate concentration exceeds 24.5 mg/l in groundwater. The relationship between the groundwater vulnerability classes and the nitrate concentrations provides satisfactory results; it showed an Eta-squared correlation coefficient of 64%. So, the groundwater vulnerability map can be used as a synthetic document for realistic management of groundwater quality.  相似文献   

15.
In this paper, groundwater aquifer vulnerability map has been developed by incorporating the major geological and hydro-geological factors that affect and control the groundwater contamination using GIS based DRASTIC model. This work demonstrates the potential of GIS to derive a map by overlying various spatially referenced digital data layers that portrays cumulative aquifer sensitivity ratings across the Kathmandu Valley, Nepal, providing a relative indication of groundwater vulnerability to contamination. In fact, the groundwater is the major natural resources in Kathmandu for drinking purpose. The decline in groundwater levels due to the over exploitation and thus extracted water from shallow aquifer has been contaminated by the infiltration of pollutants from polluted river and land surface is continuous and serious. As the demand for water for human and industrial use has escalated and at the same time, the engineering and environmental costs are much higher for new water supplies than maintaining the existing sources already in use. Management of groundwater source and protecting its quality is therefore essential to increase efficient use of existing water supplies. Aquifer vulnerability maps developed in this study are valuable tools for environmental planning and predictive groundwater management. Further, a sensitivity analysis has been performed to evaluate the influence of single parameters on aquifer vulnerability assessment such that some subjectivity can be reduced to some extent and then new weights have been computed for each DRASTIC parameters.  相似文献   

16.
This paper mainly deals with the integrated approach of remote sensing and Geographical Information System (GIS) to delineate groundwater prospective zones in Narava basin, Visakhapatnam region. The various thematic maps generated for delineating groundwater potential zones are geomorphology, geology, lineament density, drainage density, slope and land use/land cover (LULC). Weighted index overlay (WIO) technique is used to investigate a number of choice possibilities and evaluate suitability according to the associated weight of each unit. The integrated map of the area shows different zones of groundwater prospects, viz. very good (18.9% of the area), good (26.4% of the area), moderate (17.1% of the area) and poor (37.6% of the area). The categorization of groundwater potential was in good agreement with the available water column in the basin area.  相似文献   

17.
Risk assessment of land subsidence at Tianjin coastal area in China   总被引：5，自引：0，他引：5  
Risk assessment and zoning are very important to risk management. In this study, a land subsidence risk assessment index was proposed based on the Disaster Risk Index. The cumulative subsidence volume, the land subsidence velocity, and the groundwater exploitation intensity were collected, analyzed, and put together to create a land subsidence hazard evaluation map in Tianjin coastal area. The population density, Gross Domestic Product per square kilometer, and construction land proportion were adopted as indexes to create the vulnerability map. In addition, the capability of land subsidence prevention and reduction was also assessed. Finally, the land subsidence risk map was created by combing the hazard, vulnerability, and the capability of land subsidence prevention and reduction map. Specifically, the land subsidence risk was classified into five levels, i.e., very high, high, medium, low, and very low. The result of this research could provide a solid basis for the sustainable development as well as disaster prevention policy-making of Tianjin city.  相似文献   

18.
The existing different human activities and planned land uses put the groundwater resources in Jordan at considerable risk. There are evidences suggesting that the quality of groundwater supplies in north Jordan is under threat from a wide variety of point and non-point sources including agricultural, domestic, and industrial. Vulnerability maps are designed to show areas of greatest potential for groundwater contamination on the basis of hydrogeological conditions and human impacts. DRASTIC method incorporates the major geological and hydrogeological factors that affect and control groundwater movement: depth to groundwater (D), net recharge (R), lithology of the aquifer (A), soil texture (S), topography (T), lithology of vadose zone (I), and hydraulic conductivity (C). The main goal of this study is to produce vulnerability maps of groundwater resources in the Yarmouk River basin by applying the DRASTIC method to determine areas where groundwater protection or monitoring is critical. ArcGIS 9.2 was used to create the groundwater vulnerability maps by overlaying the available hydrogeological data. The resulting vulnerability maps were then integrated with lineament and land use maps as additional parameters in the DRASTIC model to assess more accurately the potential risk of groundwater to pollution. The general DRASTIC index indicates that the potential for polluting groundwater is low in the whole basin, whereas the resulting pesticide DRASTIC vulnerability map indicates that about 31% of the basin is classified as having moderate vulnerability, which may be attributed to agricultural activities in the area. Although high nitrate concentrations were found in areas of moderate vulnerability, DRASTIC method did not depict accurately the nitrate distribution in the area.  相似文献   

19.
Coastal aquifer of northern Sfax (Tunisia) suffers from the high risk to seawater intrusion and the water quality degradation due to the overexploitation. Hence, assessing the study area vulnerability to pollution is highly crucial so as to protect the groundwater resources. The assessment has been performed by applying the GALDIT method using Geographic Information System (GIS) software and multi-criteria evaluation techniques, and the sensitivity analysis approach to evaluate the effect of each GALDIT parameter on the vulnerability assessment. The GALDIT vulnerability map classifies the study area into three vulnerability classes: low vulnerability (30–50), moderate vulnerability (50–70), and high vulnerability (70–90), which represent 5, 30, and 65 % of the study area, respectively. The map illustrates that the coastal zones of the aquifer are the most threatened areas. The sensitivity analysis results show that the aquifer hydraulic conductivity (A) and the thickness of the aquifer (T) represent the determining factors in the modified vulnerability model. The real weight was used to elaborate the modified GALDIT model which was correlated with resistivity values for validation. This study could serve as a scientific basis for sustainable land planning and groundwater management in the study area.  相似文献   

20.
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.  相似文献   

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