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1.
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
2.
A modified DRASTIC model for groundwater vulnerability assessment (abbreviated as DRARCH model by combining the first letters
of its six assessment indices) was proposed. It is essentially the specific application of DRASTIC model rather than a new
model. Both natural hydrogeological conditions that prevent groundwater from contamination and important intrinsic hydrogeochemical
properties of sediments in vadose zone that are related to the retardation of contaminants were considered as vulnerability
indices. The DRARCH model consists of six indices: (1) Depth to the water table, (2) net Recharge, (3) Aquifer thickness,
(4) Ratio of cumulative thickness of clay layers to total thickness of vadose zone, (5) Contaminant adsorption coefficient
of sediment in vadose zone, and (6) Hydraulic conductivity of aquifer. The rating values and the weights of these vulnerability
indices were obtained by contaminant transport simulation and factor analysis method respectively. Furthermore, the DRARCH
model was applied to evaluate the groundwater vulnerability to arsenic contamination in Taiyuan basin, northern China, where
groundwaters with high arsenic concentration occur in some localities. GIS-based mapping of groundwater vulnerability using
this model indicates that the distribution of very high and high-vulnerability areas corresponds well to that of high-arsenic
groundwaters. The DRARCH model is therefore reliable and useful for guiding groundwater environment management. 相似文献
3.
Monitoring and methods to analyse the groundwater quality degradation risk in coastal karstic aquifers (Apulia,Southern Italy) 总被引:1,自引:0,他引:1
A multi-methodological approach based on monitoring and spatio-temporal analysis of groundwater quality changes is proposed.
The presented tools are simple, quick and cost-effective to give service to all sorts of users. The chief purpose of the monitoring
network is the detection of the piezometric or potenziometric level in the aquifer. The spatial and multi-temporal analysis
of usual chemical and physical data provides both an assessment of the spatial vulnerability of the aquifer to seawater intrusion,
defining a salinity threshold between fresh groundwater and brackish groundwater and of the water quality trend in terms of
salinity. The evaluation of the salinity trend or of salinity-correlated parameters highlights the effects of groundwater
mismanagement. The multiparameter logging provides a rapid groundwater quality classification for each well. The whole approach
allows evaluating the effects of current management criteria and designing more appropriate management targets. The Apulian
karstic coastal aquifers have been selected as a case study (Southern Italy). Three types of aquifer zones can be distinguished:
(1) areas with low vulnerability to seawater intrusion, (2) areas with high vulnerability and (3) areas with variable vulnerability
in which the salt degradation largely depends on the ability to manage the well discharge. The water quality degradation caused
by seawater intrusion appears to be a combined effect of an anomalous succession of drought periods observed from about 1980
onwards and increased groundwater pumping, particularly during drought periods. A management criterion based on aquifer zones
is proposed. 相似文献
4.
Standardization of vulnerability maps 总被引:3,自引:0,他引:3
Groundwater vulnerability assessment schemes are used for the estimation of potential groundwater contamination at different
scales and on different administrative levels. However, the term vulnerability is not standardized and the available methods
are not able to give a unique assessment of vulnerability creating thus uncertainty in the interpretation and in further application
concerning decision creation processes. To judge the information of vulnerability maps certainly and to value the general
trends of vulnerability assessment of different methods, four different vulnerability methods of the parametric system group
have been applied on a karst area in southwestern Germany to perform a comparative assessment and correlation of these vulnerability
assessment methods, namely DRASTIC, PI, EPIK, and GLA. It is shown that by means of simple statistical considerations the
first highly different vulnerability maps could be made more coherent after reclassification. The reclassified vulnerability
assessments show a more consistent vulnerability distribution pattern and provide the possibility of area-wide validation
of the maps as the chosen vulnerability classification is theoretically connected to the mean transit time of percolation
water and is largely independent of the applied vulnerability assessment method. 相似文献
5.
Assessing aquifer vulnerability to pollutants by electrical resistivity tomography (ERT) at a nitrate vulnerable zone in NE Spain 总被引:1,自引:0,他引:1
There is an increasing demand for groundwater vulnerability maps which illustrate the exposure of aquifers against pollution.
These maps show areas of greatest potential for groundwater contamination on the basis of local subsurface conditions. Parameters
affecting vulnerability are mainly permeability and thickness of each protective layer. For unconsolidated sediments, the
permeability is strongly related to the clay content, which can be deduced from indirect resistivity methods, like electrical-imaging.
Such geophysical methods can be of great help in groundwater vulnerability studies because they disturb neither the structure
nor the dynamics of the soil. Sensibility analysis was performed of the electrical resistivity tomography method for accurately
mapping soil media. Managers and public administrators may effectively use this method for assessing the potential risk of
groundwater contamination. In the studied zone, electrical resistivity exhibits a wide range of variability that can be easily
correlated to soil parameters, such as clay content and hydraulic conductivity. A numerical index of protection has been assessed
from the geophysical information derived from 2D electrical resistivity tomography. This work represents a preliminary approach
on the natural vulnerability evaluation of shallow aquifers at the Empordà basin (NE Spain) that is highly affected by diffuse
pollution by nitrates. 相似文献
6.
《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
7.
8.
Groundwater vulnerability assessment in shallow aquifer of Kathmandu Valley using GIS-based DRASTIC model 总被引:1,自引:0,他引:1
Dhundi Raj Pathak Akira Hiratsuka Isao Awata Luonan Chen 《Environmental Geology》2009,57(7):1569-1578
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
9.
The Quaternary deposits of the Ebro Basin in the surroundings of Zaragoza (Spain) form an unconfined alluvial aquifer with
a high degree of permeability and low thickness of unsaturated materials. This fact causes a high degree of vulnerability
to contamination, which implies consequences for land-use decisions and the risk management of existing industrial facilities.
In addition, in the last decades the intense irrigation and the use of pesticides is threatening the quality of the groundwater
and as a consequence the amount of usable groundwater at a low cost. Thus, the development of groundwater vulnerability maps
has great importance in a regional planning process. Consequently, groundwater vulnerability maps have been developed following
a method proposed by the German State Geological Surveys. In this paper the methodology developed within ArcGIS and Gocad,
a two- and three-dimensional software, respectively, is presented. Although the results obtained within GIS (Geographical
Information System) are acceptable it is to say that the 3D-model improves considerably the final product. 相似文献
10.
Vulnerability mapping of shallow groundwater aquifer using SINTACS model in the Jordan Valley area, Jordan 总被引:1,自引:0,他引:1
Jordan Valley is one of the important areas in Jordan that involves dense agricultural activities, which depend on groundwater resources. The groundwater is exploited from an unconfined shallow aquifer which is mainly composed of alluvial deposits. In the vicinity of the Kafrein and South Shunah, the shallow aquifer shows signs of contamination from a wide variety of non-point sources. In this study, a vulnerability map was created as a tool to determine areas where groundwater is most vulnerable to contamination. One of the most widely used groundwater vulnerability mapping methods is SINTACS, which is a point count system model for the assessment of groundwater pollution hazards. SINTACS model is an adaptation for Mediterranean conditions of the well-known DRASTIC model. The model takes into account several environmental factors: these include topography, hydrology, geology, hydrogeology, and pedology. Spatial knowledge of all these factors and their mutual relationships is needed in order to properly model aquifer vulnerability using this model. Geographic information system was used to express each of SINTACS parameters as a spatial thematic layer with a specific weight and score. The final SINTACS thematic layer (intrinsic vulnerability index) was produced by taking the summation of each score parameter multiplied by its specific weight. The resultant SINTACS vulnerability map of the study area indicates that the highest potential sites for contamination are along the area between Er Ramah and Kafrein area. To the north of the study area there is a small, circular area which shows fairly high potential. Elsewhere, very low to low SINTACS index values are observed, indicating areas of low vulnerability potential. 相似文献
11.
Lukas Plan Kurt Decker Robert Faber Michael Wagreich Bernhard Grasemann 《Environmental Geology》2009,58(2):285-297
High alpine karst plateaus are recharge areas for major drinking water resources in the Alps and many other regions. Well-established
methods for the vulnerability mapping of groundwater to contamination have not been applied to such areas yet. The paper characterises
this karst type and shows that two common vulnerability assessment methods (COP and PI) classify most of the areas with high
vulnerability classes. In the test site on the Hochschwab plateau (Northern Calcareous Alps, Austria), overlying layers are
mostly absent, not protective or even enhance point recharge, where they have aquiclude character. The COP method classifies
82% of the area as highly or extremely vulnerable. The resulting maps are reasonable, but do not differentiate vulnerabilities
to the extent that the results can be used for protective measures. An extension for the upper end of the vulnerability scale
is presented that allows identifying ultra vulnerable areas. The proposed enhancement of the conventional approach points out that infiltration conditions are of key importance
for vulnerability. The method accounts for karst genetical and hydrologic processes using qualitative and quantitative properties
of karst depressions and sinking streams including parameters calculated from digital elevations models. The method is tested
on the Hochschwab plateau where 1.7% of the area is delineated as ultra vulnerable. This differentiation could not be reached
by the COP and PI methods. The resulting vulnerability map highlights spots of maximum vulnerability and the combination with
a hazard map enables protective measures for a manageable area and number of sites. 相似文献
12.
Water vulnerability assessment in karst environments: a new method of defining protection areas using a multi-attribute approach and GIS tools (EPIK method) 总被引:42,自引:12,他引:30
Groundwater resources from karst aquifers play a major role in the water supply in karst areas in the world, such as in Switzerland.
Defining groundwater protection zones in karst environment is frequently not founded on a solid hydrogeological basis. Protection
zones are often inadequate and as a result they may be ineffective. In order to improve this situation, the Federal Office
for Environment, Forests and Landscape with the Swiss National Hydrological and Geological Survey contracted the Centre of
Hydrogeology of the Neuchatel University to develop a new groundwater protection-zones strategy in karst environment. This
approach is based on the vulnerability mapping of the catchment areas of water supplies provided by springs or boreholes.
Vulnerability is here defined as the intrinsic geological and hydrogeological characteristics which determine the sensitivity
of groundwater to contamination by human activities. The EPIK method is a multi-attribute method for vulnerability mapping
which takes into consideration the specific hydrogeological behaviour of karst aquifers. EPIK is based on a conceptual model
of karst hydrological systems, which suggests considering four karst aquifer attributes: (1) Epikarst, (2) Protective cover,
(3) Infiltration conditions and (4) Karst network development. Each of these four attributes is subdivided into classes which
are mapped over the whole water catchment. The attributes and their classes are then weighted. Attribute maps are overlain
in order to obtain a final vulnerability map. From the vulnerability map, the groundwater protection zones are defined precisely.
This method was applied at several sites in Switzerland where agriculture contamination problems have frequently occurred.
These applications resulted in recommend new boundaries for the karst water supplies protection-zones.
Received: 27 October 1997 · Accepted: 4 July 1998 相似文献
13.
14.
Quantitative Calculation of Groundwater Vulnerability Assessment Based on Quantification Theory III
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There are a lot of key qualitative variables in factors affecting groundwater vulnerability. The processing of qualitative variables of the existing superimposed index method generally relies on experience, so the results are normally subjective. Quantitative theory can handle qualitative variables quantitatively, achieve the unity of quantitative and qualitative indicators, highlight the decisive role of the main factors and reflect the actual situation more objectively. We took Yulin City as the research area to verify the feasibility and applicability of quantitative theory III, which is used for the quantitative evaluation of groundwater vulnerability. The results show that it has obvious advantage in the screening of indicators and the groundwater vulnerability partition, so it can be used as a quantitative calculation method of groundwater vulnerability assessment 相似文献
15.
This study outlines an improved method, MLPI (modified leaching potential index) model, for delineating and mapping groundwater vulnerability and assessing groundwater vulnerability to contaminants, including degradable contaminants, radioactive elements and nondegradable pollutants. The primary objective is to produce specific sensitivity maps at city or county scale that can be used for recognition of aquifer sensitivity and for protection of groundwater quality. Groundwater vulnerability assessment using the MLPI method is applied to Datong city, Shanxi Province, with the following conclusions: (1) specific vulnerability was differentiated and ; (2) groundwater vulnerability is of temporal variation. 相似文献
16.
Using groundwater levels to estimate recharge 总被引:24,自引:4,他引:24
Accurate estimation of groundwater recharge is extremely important for proper management of groundwater systems. Many different
approaches exist for estimating recharge. This paper presents a review of methods that are based on groundwater-level data.
The water-table fluctuation method may be the most widely used technique for estimating recharge; it requires knowledge of
specific yield and changes in water levels over time. Advantages of this approach include its simplicity and an insensitivity
to the mechanism by which water moves through the unsaturated zone. Uncertainty in estimates generated by this method relate
to the limited accuracy with which specific yield can be determined and to the extent to which assumptions inherent in the
method are valid. Other methods that use water levels (mostly based on the Darcy equation) are also described. The theory
underlying the methods is explained. Examples from the literature are used to illustrate applications of the different methods.
Electronic Publication 相似文献
17.
Assessment of shallow groundwater vulnerability in Dahei River Plain based on AHP and DRASTIC
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Based on the special hydrogeological conditions of the Dahei River Plain in the Inner Mongolia area, assessment of shallow groundwater vulnerability is conducted based on DRASTIC model. Each evaluation indicator weight is determined by using analytic hierarchy process (AHP). The most important indicators are lithology in soil media and vadose zone. Assessment model of shallow groundwater vulnerability of the Dahei River plain is constructed. Distribution map of vulnerability index in this area is made with the spatial analysis function of ARCGIS. The results show that the particularly sensitive area is the piedmont of the Daqing Mountain, where the upstream place of the groundwater and the south-central place of the plain has the lowest vulnerability. The assessment results are more in accordance with the actual vulnerability conditions of this area by using analytic hierarchy process, and is helpful for groundwater protection. 相似文献
18.
Main concepts of the "European approach" to karst-groundwater-vulnerability assessment and mapping 总被引:4,自引:1,他引:3
D. Daly A. Dassargues D. Drew S. Dunne N. Goldscheider S. Neale I. Popescu F. Zwahlen 《Hydrogeology Journal》2002,10(2):340-345
In order to achieve some consistency in the establishment of groundwater intrinsic vulnerability maps in Europe, a new approach
is proposed by Working Group 1 of the European COST Action 620 on "Vulnerability mapping for the protection of carbonate (karst)
aquifers". A general procedure is offered which provides consistency while allowing the required flexibility for application
to a continent and under conditions of varying geology, scale, information availability, time, and resources.
The proposed methodology is designed to be clearly more physically based than the existing vulnerability-mapping techniques.
It takes the specificity of the karstic environments into account without necessarily excluding the applicability to other
geological conditions. Combined "core factors" for overlying layers and for concentration of flow account for the relative
protection of groundwater from contamination while taking into account any bypass of the overlying layers.
A precipitation factor is distinguished for describing characteristics of the input of water to the system. Differentiation
is made between groundwater resource intrinsic vulnerability mapping and source intrinsic vulnerability mapping. For the latter,
a factor describing the karst network development is relevant. This short technical note describes a first step in the work
program of Working Group 1 of the COST Action 620. Future steps are now in progress to quantify the approach and to apply
it in various European pilot areas.
Electronic Publication 相似文献
19.
Many cities in developing countries are dependent upon groundwater for water supply. Frequently this groundwater is pumped
from semi-confined aquifers in alluvial deposits. These deeper aquifers are often considered to be protected from polluted
shallow water by intervening less-permeable layers. However, where groundwater is pumped from a semi-confined aquifer immediately
beneath a city, significant induced leakage of contaminated shallow water can occur. This may lead to a serious deterioration
of water quality in deeper aquifers in the longer-term. A simple model has been developed which provides insight into the
hydraulic controls on water quality in such semi-confined aquifers. The model provides a tool for the initial assessment and
prediction of the impact of urbanization on groundwater quality. Also, the model characterizes the key hydrogeological behaviour
through a single parameter, here termed the ‘city leakage factor’, which can be used to assess the vulnerability to contamination
by leakage. A case study of a city in Thailand illustrates the use of this model.
相似文献
Résumé Beaucoup de villes des pays en développement dépendent de l’eau souterraine pour leur alimentation en eau. Cette eau souterraine est souvent pompée dans des aquifères alluviaux semi-captifs. Ces aquifères plus profonds sont souvent considérés comme protégés des eaux peu profondes et polluées, grace à des couches intercalaires moins perméables. Cependant, dans le cas où l’eau souterraine est pompée à partir d’un aquifère semi-captif situé directement sous une ville, une drainance importante des eaux peu profondes et polluées peut être induite. Ceci peut entra?ner, à long terme, une détérioration significative de la qualité de l’eau dans les aquifères plus profonds. Un modèle simple a été construit fournissant un aper?u des contr?les hydrauliques agissant sur la qualité de l’eau dans des aquifères semi-captifs. Ce modèle est un outil permettant d’évaluer l’état initial et de prédire l’impact de l’urbanisation sur la qualité de l’eau souterraine. Le modèle caractérise également les comportements hydrogéologiques majeurs à travers un unique paramètre, nommé dans cette étude facteur de drainance de la ville“, et qui peut être utilisé pour évaluer la vulnérabilité de l’aquifère face à une contamination par drainance. L’étude de cas d’une ville en Tha?lande illustre l’utilisation de ce modèle.
Resumen Muchas ciudades de paises en desarrollo dependen del agua subterránea para el abastecimiento de agua. Frecuentemente el agua subterránea se bombea de acuíferos semi-confinados en depósitos aluviales. Estos acuíferos más profundos se protegen frecuentemente de agua somera contaminada mediante la intervencción de capas menos permeables. Sin embargo, donde el agua subterránea se bombea de un acuífero semi-confinado inmediatamente debajo de una ciudad, pueden ocurrir fugas significativas inducidas de agua somera contaminada. Esto puede conducir a un serio deterioro de calidad de agua en acuíferos más profundos en el largo plazo. Se ha desarrollado un modelo simple el cual aporta idea acerca de los controles hidráulicos en la calidad del agua en tales acuíferos semi-confinados. El modelo aporta una herramienta para la evaluación inicial y predicción del impacto de urbanización en la calidad del agua subterránea. El modelo también caracteriza el comportamiento hidrogeológico clave a traves de un solo parámetro, que aquí se denomina ′factor de fuga de la ciudad′el cual puede usarse para evaluar la vulnerabilidad a la contaminación por fuga. El uso de este modelo se ilustra con un estudio de caso de una ciudad en Tailandia.
相似文献
20.
The use of geoprocessing to assess vulnerability on the east coast aquifers of Rio de Janeiro State,Brazil 总被引:1,自引:0,他引:1
Vinicius Silva Seabra Gerson Cardoso da SilvaJr Carla Bernadete Madureira Cruz 《Environmental Geology》2009,57(3):665-674
The east coast of Rio de Janeiro State, Brazil, shows a worrying overlap between areas with intrinsic groundwater vulnerability
and the most significant urban expansion zones. It experienced a rapid population growth in recent years, mainly due to the
tourism industry, resulting in a significant pressure on drinking groundwater resources. In this regard, development and use
of techniques to control and protect areas susceptible to contamination is crucial. The elaboration of aquifer vulnerability
maps is thus extremely helpful to support water resources management. The aim of the work is to present the methodological
approach in the use of Geoprocessing techniques to obtain a suitable groundwater vulnerability model in Rio de Janeiro east
coast. Considering the existing problems and the current land use and characteristics of the study region, it is clear that
the most vulnerable areas (that is, “extreme” and “very high” vulnerability areas), coincide with the most significant zones
of urban occupation, corresponding to 11% of the total study area, demanding adoption of urgent measures in the near future.
Geoprocessing tools and remote sensing for characterization of Rio de Janeiro’s east coast aquifer vulnerability gave good
results, representing a satisfactory method for management actions at low cost. 相似文献