Mapping of groundwater quality in the Turonian aquifer of Oum Er-Rabia Basin, Morocco: a case study

This study takes the groundwater of the Moroccan limestone aquifer of Oum Er-Rabia as an example of statistical and cartographical approaches in water resources management. Statistical analyses based on frequency distribution and PCA methods revealed the homogeneity of waters with the existence of abnormal points and have helped to assess correlations between the studied variables. The mapping approach illustrated that waters are influenced by the lithology of the surrounding rocks and are of Ca–Mg–HCO₃, Ca–Mg–Cl–SO₄, and mixed types according to the Piper classification. The quality of water is of high to medium, north of the basin, but it is of medium to bad, NE and south, due to excessive contents of chloride, sulfate and nitrate. According to the US Salinity Laboratory classification, water used for irrigation in the eastern and the southern parts of the basin should take into consideration the drainage conditions, the nature of plants and the addition of gypsum doses.

Monotoring shallow groundwater quality in agricultural watersheds in Denmark

Monitoring of shallow groundwater quality is part of the Danish Agricultural Watershed Monitoring Programme. The monitoring program provides fast and field-related information on impacts of changes in agricultural practices on a watershed scale. The monitoring concept described is carried out in six well-defined hydrological basins and includes new types of groundwater nests and soil water stations. Results from the first three years are presented through examples from the clayey till watershed Lillebæk and the sandy watershed Barslund Bæk. By averaging concentrations of solutes in groundwater sampled at the same depth on a monthly basis, it is possible to evaluate trends in the overall impact of climate and different agricultural practices in a watershed on the groundwater quality. Characteristic seasonal variations in nitrate concentrations related to water level fluctuations was observed. The monitoring has demonstrated significantly higher nitrate concentrations in groundwater sampled downgradient of fields receiving manure than in groundwater sampled downgradient of fertilized fields. Significant vertical nitrate reduction downgradient of manured fields was observed in both the sandy and the clayey watershed though above the redoxcline. In the clayey till watershed fast vertical transport and insignificant nitrate reduction was observed downgradient of fertilized fields probably due to fracture and macro-pore flow.     

Comparative analysis of bacterial contamination in tap and groundwater: A case study on water quality of Quetta City,an arid zone in Pakistan

Water is an essential element on earth, which provides human a variety of services in domestic use, agriculture, or industries. However, some serious health risks of drinking water are associated with microbial contamination, particularly with fecal matter. Therefore, microbial quality assessment is considered to be a necessary component of water quality assessment. This study investigates microbial contamination of water distributary system around the city by comparing groundwater (GW) and tap water (TW) quality in Quetta city. 31 GW samples and 31 TW samples were collected in the study area during the months of September, October, and November. Fecal coliform test was carried out in laboratory and their average total coliform contamination was computed. Results showed that the TW sample were all contaminated by coliform except for Chiltan town, hence are not considered suitable for drinking without any treatment according to WHO drinking water quality standards. The average coliform concentrations were 12 in Quetta main city, 11.6 in Jinnah town, 5.3 in Satallite town, 10 in Shahbaz town and 5 in Brewery town (0/100 mL CFU) and the TW samples from the three towns were even more contaminated with E.coli. Whereas among the GW, average microbial concentrations were 1.8 in Quetta main city, 2 in Satallite town, 1.4 in Shahbaz town, and 0.4 in Chiltan town (0/100 mL CFU), respectively, which shows that the contamination is occurring within the water distributary pipeline system when the water flows through the pipelines. Moreover, this research will be valuable for researchers and administrative authorities to conduct elaborative studies, and develop new policies to prevent further deterioration of drinking water in the water distribution system by pathogenic microorganisms and ensure safe drinking water to the public of Quetta city.     

Evaluation of groundwater quality and pollution in Daqing Oilfield

Daqing Oilfield is located in the northeast of Songnen Plain in Daqing City, Heilongjiang Province, which is a petrochemical industry gathering place based on petroleum refining, chemical industry, chemical fiber and fertilizer. In recent years, the quantity demand of petroleum and petrochemical production for groundwater in Daqing Oilfield is growing, and it’s of great significance to analyze and study the quality and pollution degree of groundwater for groundwater exploitation, utilization and protection. In this paper, groundwater quality of Daqing Oilfield evaluated by Nemerow Index is poor, and most points are Class IV groundwater; When evaluating groundwater pollution by hierarchical ladder method, the results show that the severe and extremely severe pollution points account for 34.48% in shallow phreatic water and 20% in deep confined water, showing that shallow groundwater is more seriously polluted than the deep. The main components influencing the quality of groundwater in the study area are total hardness, total dissolved solids, Cl-, SO42- and so on, which are affected by both the native environment and human activities; The main pollution components in groundwater are nitrite and nitrate nitrogen which are affected by human activities. Daqing Oilfield groundwater pollution is characterized by inorganic pollution, while organic components related to human activities contribute less to the groundwater pollution currently.     

Evaluation of groundwater quality in coastal areas: implications for sustainable agriculture

Seawater intrusion is a problem in the coastal areas of Korea. Most productive agricultural fields are in the western and southern coastal areas of the country where irrigation predominantly relies on groundwater. Seawater intrusion has affected agricultural productivity. To evaluate progressive encroachment of saline water, the Korean government established a seawater intrusion monitoring well network, especially in the western and southern part of the peninsula. Automatic water levels and EC monitoring and periodic chemical analysis of groundwater help track salinization. Salinization of fresh groundwater is highly associated with groundwater withdrawal. A large proportion of the groundwaters are classified as Na–Cl and Ca–Cl types. The Na–Cl types represent effects of seawater intrusion. The highest EC level was over 1.6 km inland and high Cl values were observed up to 1.2 km inland. Lower ratios of Na/Cl and SO₄/Cl than seawater values indicate the seawater encroachment. A linear relation between Na and Cl represents simple mixing of the fresh groundwater with the seawater. The saline Na–Cl typed groundwaters showed Br/Cl ratios similar to or less than seawater values. The Ca–HCO₃ type groundwaters had the highest Br/Cl ratios. Substantial proportions of the groundwaters showed potential for salinity and should be better managed for sustainable agriculture.     

Salinity mapping of coastal groundwater aquifers using hydrogeochemical and geophysical methods: a case study from north Kelantan,Malaysia

Integrated hydrogeochemical and geophysical methods were used to study the salinity of groundwater aquifers along the coastal area of north Kelantan. For the hydrogeochemical investigation, analysis of major ion contents of the groundwater was conducted, and other chemical parameters such as pH and total dissolved solids were also determined. For the geophysical study, both geoelectrical resistivity soundings and reflection seismic surveys were conducted to determine the characteristics of the subsurface and groundwater contained within the aquifers. The pH values range from 6.2 to 6.8, indicating that the groundwater in the study area is slightly acidic. Low content of chloride suggests that the groundwater in the first aquifer is fresh, with an average concentration of about 15.8 mg/l and high geoelectrical resistivity (>45 ohm m). On the other hand, the groundwater in the second aquifer is brackish, with chloride concentration ranging from 500 mg/l to 3,600 mg/l and very low geoelectrical resistivity (<45 ohm m) as well as high concentration of total dissolved solids (>1,000 mg/l). The groundwater in the third aquifer is fresh, with chloride concentrations generally ranging from 2 mg/l to 210 mg/l and geoelectrical resistivity of greater than 45 ohm m. Fresh and saltwater interface in the first aquifer is generally located directly in the area of the coast, but, for the second aquifer, both hydrogeochemical and geoelectrical resistivity results indicate that the fresh water and saltwater interface is located as far as 6 km from the beach. The considerable chloride ion content initially suggests that the salinity of the groundwater in the second aquifer is probably caused by the intrusion of seawater. However, continuous monitoring of the chloride content of the second aquifer indicated no significant changes with time, from which it can be inferred that the salinity of the groundwater is not affected by seasonal seawater intrusion. Schoeller diagrams illustrate that sulphate concentrations of the groundwater of the second aquifer are relatively low compared to those of the recent seawater. Therefore, this result suggests that the brackish water in the second aquifer is probably from ancient seawater that was trapped within the sediments for a long period of time, rather than due to direct seawater intrusion.     

Identification and mapping of chromium (VI) plume in groundwater for remediation: A case study at Kanpur,Uttar Pradesh

With only twenty five percent population living in urban areas, India has cities amongst the biggest in the world. Urban growth in most of Indian cities is concomitant with rise in water demand for community, as well as, for industrial purposes. The complex situation resulting from indiscriminate disposal of waste and its severe impact on groundwater quality is set for continuous worsening mainly for want of sustained effort aimed at site-specific remediation. The study, a prerequisite for actual remediation in an industrial city of Kanpur, India, envisages detailed investigation about pollutant transport, evaluation of concept of Bio-remediation and a range of other options and finally full scale implementation of the best suited. Drilling of piezometers and resistivity survey indicates that the area is constituted of alluvial sands, gravels and their various admixtures. Chemical analysis of water samples collected from piezometers and hand pumps shows the presence of hexavalent chromium rich horizons at various depths. The alarming concentration of this carcinogenic heavy metal of the order of 16.3 mg/l against the permissible concentration (of 0.05 mg/l) for drinking water and high concentration within sediments of the area poses a major threat to the entire ecosystem. The projection of migration contaminant plume of hexavalent chromium as depicted in the paper is indicative of a concentrated extent of core zone existing in shallow alluvial aquifer, which may be targeted for interception by remedial measures. The present work, elaborating on the source, potential and monitoring the migration of the pollutant plume is the first field scale study of its kind in the country. The findings of these studies are of strong relevance in addressing the ground water pollution due to indiscriminate disposal practices of hazardous waste in areas located within the alluvial zones.     

Determination of groundwater availability in shallow arid region aquifers utilizing GIS technology: a case study in Hada Al-Sham, Western Saudi Arabia

A simple, physically based method is developed in this paper to assist in the allocation of areas with high groundwater potential and for the determination of maximum allowed pumping rate to ensure proper groundwater management. This method utilizes the aquifer physical properties as well as GIS technology to accomplish this purpose. The design of this method was considered to be applicable in areas with little data, such as in most arid regions. This technique was applied to a catchment in an arid environment where qualitative as well as quantitative analyses of the results were undertaken. Locations of available groundwater and rates of maximum allowable pumping were compared with observations and experiments in the field and a good agreement was found. It was concluded that the best groundwater location was in the alluvial area, which represents only 16% of the total aquifer, which is a typical case in arid region catchments. The rate of maximum pumping was estimated to be 65 m³/h. However, to benefit 55% of the area, the maximum pumping rate should only be 40 m³/h with an average rate throughout the area (55%) of about 24 m³/h.This revised version was published online in December 2004 with corrections to the category.     

Groundwater quality in a coastal area: a case study from Andhra Pradesh, India

Over-exploitation of groundwater results in decline of water levels, leading to intrusion of salt water along the coastal region, which is a natural phenomenon. A groundwater quality survey has been carried out to assess such phenomena along the coast of Visakhapatnam, Andhra Pradesh, India. Brackish groundwaters are observed in most of the wells. The rest of the wells show a fresh water environment. The factors responsible for the brackish groundwater quality with respect to the influence of seawater are assessed, using the standard ionic ratios, such as Ca²⁺:Mg²⁺, TA:TH and Cl⁻:HCO⁻ ₃. Results suggest that the brackish nature in most of the groundwaters is not due to the seawater influence, but is caused by the hydrogeochemical process. Some influence of seawater on the groundwater quality is observed along the rock fractures. The combined effect of seawater and urban wastewaters is due to the inferior quality of groundwater in a few wells, where they are at topographic lows close to the coast.     

Identification of sources of chemical constituents in groundwater from the Vilnius wellfields, Lithuania

The only source of drinking water in Vilnius City, Lithuania's capital, is groundwater. It can be supplied from 20 wellfields situated in the City or its environs. About half of them (11) are located in the valley of the Neris River crossing the City. The exploited aquifers were formed by melting continental glaciers and modified by the river. Until 1990 groundwater resources had not been conserved—the per capita consumption for domestic use in Vilnius reached 350 l/day. After 1990, due to the increasing cost of supplying drinking water, its consumption was reduced by a factor of three. As pumping rates of wellfields in Vilnius were increased or decreased, the groundwater quality was changed significantly. It is mainly affected by the surface water and shallow aquifers of the hydrologic system. The unoxidised organic matter that enters the exploitable aquifers from rivers and polluted shallow groundwater consumes scarce oxygen resources, thus creating anoxic conditions favourable for increasing the accumulation of iron, manganese and ammonium. Modelling and monitoring data show that the concentrations of sulphates and chlorides in Vilnius wellfields indicate not only the rise of brackish water from below, but also downward seepage of polluted surface water into the aquifers.     

Assessment of groundwater quality for drinking and irrigation purposes: a case study of Peddavanka watershed, Anantapur District, Andhra Pradesh, India

In India, the quantity and quality of water available for irrigation is variable from place to place. Assessment of water quality has been carried out to determine the sources of dissolved ions in groundwater. Quality of groundwater in a 398 km² Peddavanka watershed of a semi-arid region of south India is evaluated for its suitability for drinking and irrigation purposes. The middle Proterozoic Cuddapah Supergroup and Kurnool Group of rocks underlie most of the watershed. The main lithologic units consist chiefly of quartzite, limestone, and shale. Seventy-six water samples were collected from open-wells and bore-holes. Water samples were collected representative of the post-monsoon (winter) and pre-monsoon (summer). The quality assessment is made through the estimation of Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, SO₄²⁻, CO₃²⁻, HCO₃⁻, total hardness as CaCO₃, TDS, EC, and pH. Based on these analyses, parameters like sodium adsorption ratio, % sodium, residual sodium carbonate, non-carbonate hardness, potential salinity, Kelley’s ratio, magnesium ratio, index of base exchange and permeability index were calculated. According to Gibbs‘ ratio samples in both seasons fall in the rock dominance field. The overall quality of waters in the study area in post-monsoon season is high for all constituents ruling out pollution from extraneous sources.     

洞庭湖区浅层地下水质量现状与安全供水研究

通过对1720个水质分析样品资料的深入分析与计算,系统地评价了洞庭湖区浅层地下水质量,指出了浅层地下水安全供水方向,并提出了安全供水措施及建议。计算结果认为,洞庭湖区浅层地下水中的污染因子主要为Fe、Mn、PH、NH4-N及NO2-N,其次为NO3-N、Be、COD,共8个因子,基本上没有遭受重金属污染;湖区浅层地下水水质整体较好,以优质水为主,占39.37%,合格水占26.04%;不合格水(较差水)占34.59%。     

Using soil and Quaternary geological information to assess the intrinsic groundwater vulnerability of shallow aquifers: an example from Lithuania

Lithuania, in the Baltic region of northern Europe, is heavily dependent on groundwater resources for its public water supply, with a large proportion, especially in rural areas, derived from shallow Quaternary aquifers. A national groundwater-vulnerability methodology, based upon the UK approach, has been developed on behalf of the Lithuanian Ministry of Environmental Protection as a possible basis for the future protection of shallow groundwater resources for the rural inhabitants. Some modifications to the UK methodology were required to enable archive data to be used. The four aquifer classes depicted on the final groundwater vulnerability map are based upon the assessed relative permeabilities of the uppermost Quaternary deposits. The derivation of the classification of soil-leaching potential required a reassessment of Soviet-based soil wetness and particle-size classes and a calculation of subsoil-saturated hydraulic conductivity. A preliminary validation of the final maps against available shallow groundwater samples suggests that the methodology satisfactorily predicts the intrinsic groundwater vulnerability. The final methodology, based upon its low-cost approach using archive data, is relevant to the current needs of Lithuania and can be applied in other regions of similar geology and climate. Electronic Publication     

Geographic Information System and groundwater quality mapping in Panvel Basin,Maharashtra, India

Panvel Basin of Raigarh district, Maharashtra, India is the study area for groundwater quality mapping using the Geographic Information System (GIS). The study area is typically covered by Deccan basaltic rock types of Cretaceous to Eocene age. Though the basin receives heavy rainfall, it frequently faces water scarcity problems as well as water quality problems in some specific areas. Hence, a GIS based groundwater quality mapping has been carried out in the region with the help of data generated from chemical analysis of water samples collected from the basin. Groundwater samples show quality exceedence in terms of chloride, hardness, TDS and salinity. These parameters indicate the level of quality of groundwater for drinking and irrigation purposes. Idrisi 32 GIS software was used for generation of various thematic maps and for spatial analysis and integration to produce the final groundwater quality map. The groundwater quality map shows fragments pictorially representing groundwater zones that are desirable and undesirable for drinking and irrigation purposes.     

Vulnerability mapping of shallow groundwater aquifer using SINTACS model in the Jordan Valley area, Jordan

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.     

Non-point pollution of groundwater from agricultural activities in Mediterranean Spain: the Balearic Islands case study

Mediterranean Spain is a region with intensive agricultural production combined with an important seasonal water demand for water supply. High application rates of inorganic nitrogen fertiliser, input of plant protection products and intensive irrigation, sometimes with treated wastewater, is a common practice. As a result, most aquifers show nitrate contamination problems of agricultural origin. Data on pesticide residues is scarce, as systematic monitoring is not currently done. In Majorca Island, values up to 700 mg/l of nitrate in groundwater have been observed. To analyse the current situation derived from non-point pollution, several actions have been taken at different scales: declaration of a nitrate vulnerable zone, field experiments to evaluate nitrogen transport to the aquifer and the development of a GIS-simulation model to generate nitrate risk maps.     

考虑样本差异的一种地下水质模糊评判方法与应用

应用传统模糊评判方法评价地下水质量时,通常以地下水质量标准为参考进行权重赋值,没有考虑由于水质复杂而引起的评价地区内部各取样点测试指标值之间的差异,评价结果极有可能出现一个样本因某项指标的相对含量较大而被列为水质较差级别的现象,不能为水资源缺乏地区水资源管理提供客观的依据。本文针对传统模糊评判的不足,选用广义权海明距离公式为评价公式,用样本权重来表达样本差异程度,再和标准权重相结合作为总的权重,建立了考虑样本差异的地下水质模糊评判体系。选择pH、溶解性总固体、总硬度、Cl-、SO42-和NO3-作为评价指标,分别运用传统模糊评判和考虑样本差异的模糊评判法对鄂尔多斯白垩系自流水盆地的环河组含水岩组进行地下水质量评价。评价结果表明,考虑样本差异的模糊评判所得的Ⅳ、Ⅴ类水分布面积明显小于传统模糊评判所得的结果,环河组含水岩组地下水水质的Ⅰ、Ⅱ、Ⅲ级主要分布在盆地的北部,盆地南部的地下水质明显劣于盆地北部。影响水质分布的因素主要有水化学场、水动力场、岩相古地理等。     

Pumping decisions for sustainable development of groundwater resources in areas of grassland degradation: a case study in Lanqi Banner, Inner Mongolia, China

The best planting alternatives for satisfying high water use demands of forage and fodder crops in a region of Inner Mongolia, China, were determined by a multiobjective distributed-parameter groundwater management model. These alternatives took account of different cropping patterns and pumping decisions associated with both temporal and spatial aspects of water allocation. The model was developed for phreatic, homogenous, and isotropic aquifers using the response matrix technique of quadratic programming theory and, in this case, using the alternative direction implicit (ADI) scheme. Model solutions using effective rainfall with a probability of 50%, show that average water table drawdown in the planning period (2006–2017) is 0.22 m and the groundwater fluctuation in each pumping well is very low. In order to evaluate the pumping decisions under an effective rainfall with a probability of 75%, a sensitive analysis was also conducted. Analysis shows that it is useful to apply the results from the proposed model to control the landscape degradation due to overgrazing and overpumping activities.     

Hydrogeological mapping as a basis for establishing site-specific groundwater protection zones in Denmark

The water supply in Denmark is based on high-quality groundwater, thus obviating the need for complex and expensive purification. Contamination from urban development and agricultural sources, however, increasingly threatens the groundwater resource. In 1995 the Danish Government thus launched a 10-point plan to improve groundwater protection. In 1998 this was followed by a decision to instigate spatially dense hydrogeological mapping of the groundwater resource within the 37% of Denmark designated as particularly valuable water-abstraction areas. The maps will be used to establish site-specific groundwater protection zones and associated regulation of land use to prevent groundwater contamination. Traditional mapping based solely on borehole data is too inaccurate for this purpose. The work will take 10 years and cost an estimated DKK 920 million, equivalent to 120 million euro (€). To fund this, consumers will pay a € 0.02 surcharge per m³ of drinking water during the 10-year period. This review of the Danish strategy to protect the groundwater resource demonstrates why dense mapping with newly developed geophysical measurement methods in large contiguous areas accords geophysics a highly central role in the forthcoming hydrogeological mapping. It is illustrated by examples of spatially dense, large-scale geophysical mapping carried out in the Aarhus area.

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Resumen El abastecimiento de agua en Dinamarca está basado en agua subterránea de alta calidad, evitando de esta manera la necesidad de una purificación compleja y cara. Sin embargo, la contaminación a través del desarrollo urbano y de fuentes agrícolas, ha incrementado la amenaza para el recurso de agua subterránea. Entonces en 1995 el gobierno lanzó un plan de 10 puntos para mejorar la protección del agua subterránea. Este fue seguido en 1998 por la decisión para promover una cartografía hidrogeológica espacialmente detallada, para el recurso agua subterránea dentro del 37% de las áreas de extracción consideradas por Dinamarca con una importancia especial. Los mapas serán usados para establecer zonas específicas de protección para puntos de agua subterránea y una regulación asociada al uso del territorio, para prevenir la contaminación del agua subterránea. La cartografía tradicional basada exclusivamente en datos de la perforación es muy inexacta para este propósito. Este trabajo tomará 10 años y costará aproximadamente DKK 920 millones, equivalentes a 120 millones de Euros (€). Para financiar esto los consumidores pagarán un sobreprecio de € 0.02 por m³ de agua potable durante un periodo de 10 años. Este análisis de la estrategia Danesa para proteger el recurso agua subterránea, demuestra porque la cartografía detallada, hecha con nuevos avances en métodos de medición geofísica, aplicados a grandes áreas aledañas, otorgan a la geofísica un papel altamente importante en el futuro de la cartografía hidrogeológica. Esto está ilustrado con ejemplos de cartografía geofísica a gran escala y espacialmente detallada, llevados a cabo en el área de Aarhus.

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Résumé Lalimentation en eau au Danemark suppose une haute qualité des eaux souterraines, en éliminant ainsi le coûteux processus dépuration. Néanmoins, la qualité des sources souterraines est menacée par la pollution provoquée par le développement urbain et agricole. En 1995 le gouvernement danois a lancé un plan en 10 points pour améliorer la protection des eaux souterraines. En 1999 ce plan a été suivi par la décision de promouvoir une cartographie hydrogéologique à grande densité sur 37% du territoire du Danemark où se trouvent des zones de captages importantes. Les cartes seront utilisées pour établir les zones de protection des eaux souterraines, en tenant compte des conditions locales du site ainsi que des règlements conjoints dutilisation des territoires, afin de prévenir la pollution des eaux souterraines. La cartographie traditionnelle, basée seulement sur les données des forages, est trop imprécise pour ce but. Les travaux vont durer 10 ans avec un coût estimé à 120 millions deuros (€). Pour ces travaux les consommateurs vont payer une surcharge de € 0.02 par m³ deau potable, ceci pendant 10 ans. Cette révision de la stratégie du Danemark concernant la protection des ressources en eaux souterraines a démontré les raisons pour lesquelles on a accordé un rôle central aux nouvelles méthodes géophysiques dans la future cartographie hydrogéologique de vaste régions. On présente un exemple de cartographie géophysique réalisée dans la région dAarhus.