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1.
Flow and transport model of a polder area in the Belgian coastal plain: example of data integration 总被引：1，自引：1，他引：0
Alexander Vandenbohede Klaus Hinsby Carolien Courtens Luc Lebbe 《Hydrogeology Journal》2011,19(8):1599-1615
Tracer data can serve to derive parameters related to groundwater systems or can be used in the calibration of transport and flow models. Temperature, 3H/3He (age dating) and hydrochemical data, together with head measurements, borehole logs and an aquifer test, were used to obtain insight into the flow and transport of a Quaternary aquifer system located in the Belgian polder area. Flow and transport model code SEAWAT acted as the integration medium for the different data. Each type of data has its own interpretation technique and adds components to the model. Additionally, different types of data aid in verification of the results. For instance, fluxes from temperature logs (used with the SEAWAT model), and water quality and age dating all provide information on flow to and velocities in the vicinity of drainage ditches. Different data also provide information on different scales. Temperature logs and aquifer tests act on a small scale, groundwater age is influenced by larger-scale flow, and water quality is determined by the general flow of the area. Integration of different kinds of geological, hydrological, geophysical and geochemical data is shown to be an important way forward in the efforts to model real-world cases. 相似文献
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3.
A geophysical and geochemical approach for seawater intrusion assessment in the Acquedolci coastal aquifer (Northern Sicily) 总被引：2，自引：0，他引：2
Vertical electrical sounding (VES’) surveys and chemical analyses of groundwater have been executed in the coastal plain of
Acquedolci (Northern Sicily), with the aim to circumscribe seawater intrusion phenomena. This urbanized area is representative
of a more general problem interesting most of Mediterranean littoral areas, where intensive overdraft favors a heavy seawater
intrusion through the coastline. Aquifer resistivity seems decisively to be conditioned by the chlorine and magnesium content
in the main aquifer of the region. Schlumberger VES’, together with piezometric and chemical–physical information of groundwater,
allowed us to perform hydrogeological and geophysical elaborations, to propose the occurrence of a relatively narrow belt
marked by fresh–salt water mixing. In the considered plain, pollution risk studies have been already realized by authors with
the proposal to identify—by parametric and synthetic zoning of significant hydrogeological elements—the most vulnerable sectors.
In detail, an intrinsic vulnerability mapping has been already performed, applying the well-known SINTACS system. This paper
intends to give—in this sector of Sicily—an example of integration of different methodologies, showing the role of geophysics
to describe the degradation of aquifers on the whole as well as to assess their pollution risk better. 相似文献
4.
The Memphis aquifer in southwestern Tennessee is a confined to semi-confined unconsolidated sand aquifer and is the primary
municipal water source for the Memphis metropolitan area. Leakage of modern water from shallow unconfined aquifers through
the upper Claiborne confining unit locally degrades water quality in the Memphis aquifer and makes the aquifer more vulnerable
to contamination. Major solute chemistry, tritium, and 3H/3He data were used to investigate the source and mixing proportions of modern water in the Memphis aquifer in the Davis well
field, Memphis, Tennessee. Water quality in several production wells in the Davis well field has declined over the past 30 years,
mainly through increased total dissolved solids, iron, alkalinity, and hardness. Trends in chemical data, tritium, and other
hydrogeologic data support a source for the leakage from the Mississippi River Valley Alluvial aquifer. Mixing proportions
of alluvial water in production well water obtained by inverse chemical modeling with PHREEQCi range from 7 to 45%. For two
of the production wells, MLGW 414 and 432, 3H/3He data yield mixing ratios similar to those obtained from PHREEQCi in three of four cases; the dissimilar ratio is likely
due to a poor solution from the PHREEQCi inverse modeling. Modeling of the age distribution obtained from MLGW 414 and 432
using an exponential-piston flow model (EPM) with an inverse solution computer code yielded mixed results. The EPM solution
obtained for MLGW 414 converged with difficulty only for a 5-year transit time in the shallow aquifer and is consistent with
a source from the Mississippi River Valley Alluvial aquifer; however, the modeled age of the water is greater than that observed.
In comparison, the EPM solution for MLGW 432 converged for the 5- and 7-year transit periods in the shallow aquifer and yielded
model ages consistent with observed 3H/3He ages; however, the extent of the maximum radii for infiltration source is not consistent with a Mississippi River Valley
Alluvial aquifer source. Other potential sources for leakage to MLGW 432 include water from the Fluvial-terrace aquifer migrating
along a fault east of the well field or infiltration of water from a lake south of the well field. 相似文献
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The Southern Aravalli Fold Belt represents a geologically complex terrain comprising migmatites, gneisses, low-grade metasediments
and intrusive granites. Processing and interpretation of the existing aeromagnetic data using modern techniques has helped
in understanding the geological complexity of the area. High quality aeromagnetic maps — total intensity, vertical derivative,
analytic signal and 3D Euler depth — have been produced from the digitally processed data to augment visualisation and interpretation
of the data. Strong east-west to northeast-southwest long strike-length anomalies in the southern part within the gneissic/granitic
terrain indicate presence of narrow bands of high-susceptibility (magnetic) materials probably along regional lineaments.
The thick sequence (> 1 km) of magnetically transparent sedimentary cover in the Rajgad basin is better visualised in the
analytic signal and Euler Depth maps. The sediments in the northern part of the basin are deposited in a grabben formed by
a northwest-southeast trending marginal fault in the north and an intrabasinal east-west fault in the south as demonstrated
in the Euler 3D map. The Lunavada and Champaner Groups are separated by a shear zone comprising en-echelon shears clearly
indicated in the shaded relief and vertical derivative maps. Interpretation of magnetic relief of the aeromagnetic data reveals
that the area comprises of five distinct litho-tectonic units. This study demonstrates that the old aeromagnetic data acquired
few decades back can provide valuable geological information, if processed using modern techniques. 相似文献
7.
L. W. Daesslé L. G. Mendoza-Espinosa V. F. Camacho-Ibar W. Rozier O. Morton L. Van Dorst K. C. Lugo-Ibarra A. L. Quintanilla-Montoya A. Rodríguez-Pinal 《Environmental Geology》2006,51(1):151-159
The Guadalupe Valley aquifer is the only water source for one of the most important wine industries in Mexico, and also the main public water supply for the nearby city of Ensenada. This groundwater is monitored for major ion, N-NO3, P-PO4, Fe, As, Se, Mo, Cd, Cu, Pb, Zn and Sb concentrations, as well as TDS, pH, dissolved oxygen and temperature. High concentrations of N-NO3 (26 mg l−1), Se (70 μg l−1), Mo (18 μg l−1) and Cu (4.3 μg l−1) suggest that groundwater is being polluted by the use of fertilizers only in the western section of the aquifer, known as El Porvenir graben. Unlike the sites located near the main recharge area to the East of the aquifer, the water in El Porvenir graben has low tritium concentrations (<1.9 TU), indicating a pre-modern age, and thus longer water residence time. No significant variations in water quality (generally <10%) were detected throughout 2001–2002 in the aquifer, suggesting that reduced rainfall and recharge during this dry period did not significantly affect water quality. However, the wells nearest to the main recharge area in the Eastern aquifer show a slight but constant increase in TDS with time, probably as a result of the high (∼200 L S−1) uninterrupted extraction of water at this specific recharge site. Relatively high As concentrations for the aquifer (10.5 μg l−1) are only found near the northern limit of the basin associated with a geological fault. 相似文献
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为准确获取水文地质参数,进而为矿井防治水、矿井涌水量计算以及地下水评价等提供可靠的参数,以煤田地质勘探中实测的人工井液电阻率测井曲线为依据,结合岩心精细描述、抽水试验、常规地球物理测井等技术获得的资料进行综合分析。研究表明:人工井液电阻率测井技术在煤田水文地质勘探中不仅可以准确划分含隔水层的性质,确定其位置,分析含水层之间的补给关系,检查钻孔止水效果,计算各含水层钻孔截面流量,亦可研究地下水流体特征,评价地下水水质参数以及监测生产矿井导水裂隙带高度。因此,人工井液电阻率测井能够提高煤田水文地质勘探成果利用率,实现地质勘探信息的最大化利用,从而更好地为矿井设计、建设及矿井生产服务,保障矿井安全。 相似文献
10.
Engineering geophysics provides valuable and continuous information for the planning and execution of tunnel construction
projects. For geotechnical purposes special high-resolution geophysical methods have been developed during the last decades.
The importance of applying geophysical methods in addition to usually used geological and geotechnical exploration techniques
is increasing. The main goal is to achieve an accurate and continuous model of the subsurface in a relative short period of
operation time. The routine application of engineering geophysical methods will increase in the coming years. Due to the high
acceptance of engineering geophysics at construction sites, much wider application of geophysical investigations is expected.
The combination of different methods—geophysics, geology, and geotechnics as well as the so-called joint interpretation techniques—will
be of essential importance. Engineering geophysics will play an important role during the three phases: geological investigation,
tunnel planning, and execution of tunnel construction. If hazards are well known in advance of a tunnel project the safety
of workers will essentially be increased and geological risks will be minimized by means of successful and interdisciplinary
cooperation. 相似文献
11.
A case study was conducted to find the groundwater potential zones in an area between the Serang and Bogowonto rivers, Kulon Progo Regency, Java, Indonesia. The objectives of this study were to delineate the groundwater potential zone based on a number of groundwater parameters that can be surveyed in the field and to incorporate the geomorphological conditions into these data. The geomorphology interpretation was conducted using the landform approach. This approach begins by preparing supporting data such as an Indonesian Topographic Map containing contour and land use data; a regional geology map containing lithology type and geology structures; and soil, climate, and hydrological data. The determination of the geomorphology unit was conducted manually by the visual interpretation of Digital Landsat ETM+ with some image interpretation keys. Four groundwater parameters were surveyed in the field: (a) depth to the water table, (b) water table fluctuation, (c) fluid electrical conductivity to represent groundwater quality, and (d) aquifer thickness. The groundwater potential zones were obtained by overlaying all the groundwater field parameters in terms of weighted overlay methods using the spatial analysis tool in ArcGIS 9.2. During the weighted overlay analysis, rankings were produced for each individual parameter of each groundwater field parameter, and weights were assigned based on the amount of influence they had (i.e., depth to the water table—30 %, water table fluctuation—20 %, aquifer thickness—30 %, and fluid conductivity—20 %). We then found the good, moderate, and poor zones in terms of groundwater potential, which had areas of 5.83, 4.53, and 2.36 km2, respectively. Areas with good groundwater potential are located largely within sand dunes, beach ridges, beaches, and fluviomarine plain landforms, which are characterized by a shallow water table, low fluctuation, thick aquifer, and low EC value. Moderate groundwater zones are generally characterized by poor water quality (high EC value), which is found to some degree in the alluvial plain. The regions with poor groundwater potential are spread mainly across the landforms composed of igneous rock (thin aquifers), such as denudational hills, which act as run-off zones due to their steep slope. 相似文献
12.
The present work was conducted in the Sinai Peninsula (1) to identify the recharge and flow characteristics and to evaluate
the continuity of the Lower Cretaceous Nubian Sandstone aquifer; and (2) to provide information for the aquifer's rational
appraisal. Isotopic and hydrochemical compositions combined with the geological and hydrogeological settings were used for
this purpose.
A considerable depletion in isotopic content (oxygen-18 and deuterium) and low d-excess values exist in the studied groundwater,
reflecting the contribution of old meteoric water that recharged the aquifer in pluvial times. Modern recharge also occurs
from precipitation that falls on the aquifer outcrops. The wide scatter of the data points around the two meteoric lines,
the global meteoric water line (GMWL) and Mediterranean meteoric water line (MMWL), in the δ18O–δD diagram indicates considerable variation in recharge conditions (amount, altitude, temperature, air masses, distances
from catchment, overland flow, etc.). The isotopic composition in the El-Bruk area is minimum (18O=–9.53‰), very close to the average value of the Western Desert Nubian Sandstone (18O=–10‰), where the local structural and lithologic conditions retard groundwater flow and the main bulk of water becomes noncyclic.
The continuity of the aquifer in northern and central Sinai is evidenced by the isotopic similarity between samples taken
from above and below the central Sinai Ragabet El-Naam fault, the distribution of potentiometric head, and hydrogeological
cross sections.
The combination of isotopic composition in terms of 18O and chemical composition in terms of TDS and salt contents is the basis for separating the studied groundwater into groups
that reflect the recharge sources and isotopic and chemical modifications during flow.
Electronic Publication 相似文献
13.
为实现青藏高原矿山地质环境影响调查项目从论证-设计-调查-成果4个阶段全过程的数据标准化、规范化录入、使用和管理,基于Microsoft Windows XP、Windows7操作系统开发了"青藏高原矿产资源开发地质环境影响调查信息系统",系统包括数据录入、数据集成、评价管理3个模块。数据录入模块实现了各阶段数据的规范录入,数据集成模块实现了将各个工作项目录入数据进行集成的功能,评价管理模块实现了对调查数据、测试数据进行自动评价并将调查矿山信息在GIS图上进行定位、查询及分析的功能,系统的研发和应用为矿山地质环境调查全流程实现信息化管理服务提供了平台。 相似文献
14.
Hydrochemical framework of the aquifer in and around East Kolkata Wetlands,West Bengal,India 总被引：1，自引：0，他引：1
The area lies between Hugli river in the northwest and Bidyadhari river in the east and includes the East Kolkata Wetlands.
The East Kolkata Wetlands is included in the List of Wetlands of International Importance (“Ramsar List”), as per the Convention
on Wetlands signed in Ramsar, Iran, in 1971. This wetland has been declared as a Ramsar site on the 19th August 2002 (Ramsar
site no. 1208) and therefore has acquired an international status. The area is a part of the lower deltaic plain of the Bhagirathi–Ganga
river system and is generally flat in nature. The sub-surface geology of the area is completely blanketed by the Quaternary
fluviatile sediments comprising a succession of clay, silty clay, sand and sand mixed with occasional gravel. The Quaternary
aquifer is sandwiched between two clay sequences. The confined aquifer is made up of moderately well sorted sand and reflects
fluviatile environment of deposition. The regional groundwater flow direction is from east to west. Detailed geochemical investigations
of 40 groundwater samples along with statistical analysis (for example, correlation and principal component analysis) on these
chemical data reveal: (i) four types of groundwater quality, for example, good, poor, very poor and water unsuitable for drinking
purpose, (ii) four hydrochemical facies which may be assigned to three broad types such as “fresh”, “blended”, and “brackish”
waters, (iii) the evolution of the “blended” water is possibly due to hydraulic mixing of “fresh” and “brackish” waters within
the aquifer matrix and/or in well mixing, and (iv) absence of Na–Cl facies indicates continuous flushing of the aquifer. 相似文献
15.
Systematic GIS-based landslide inventory as the first step for effective landslide-hazard management 总被引：1，自引：1，他引：1
The purpose of the so-called IFFI project (Inventario dei Fenomeni Franosi in Italia—Inventory of Landslides in Italy) and of many other related activities carried out by the Centro Regionale per le Ricerche Territoriali e Geologiche of ARPA Piemonte (Agenzia Regionale per la Protezione Ambientale—Regional Agency for Environmental Protection), is to map all the existing landslides in Piemonte (including both results of monitoring data and available historical data). ARPA carried out new systematic surveys using
airphoto interpretation and created a specific alphanumeric geological information systems (GIS)-based database to store and
process all the collected data. In order to obtain proper landslide-hazard zoning, it is necessary to provide a landslide
inventory and to define the relationship between landslides and geological setting. A landslide inventory represents a fundamental
base of knowledge, is a very basic tool for land planning, and strongly helps the local authorities in their decision making. 相似文献
16.
The demand for water resources in the area south of the Dead Sea due to continued development, especially at the Arab Potash
Company (APC) works necessitates that water quality in the area be monitored and evaluated based on the local geology and
hydrogeology. The objective of this paper is to provide information on the past and present status of the main aquifers under
exploitation or planned for future development. Two main aquifers are discussed: the Safi water field, presently being operated,
and the Dhiraa water field, which is being developed. The aquifer developed in the Safi water field is shallow and fed by
the Hasa fault system, which drains a significant portion of the Karak mountains. This aquifer seems to be well replenished
within the core, where no obvious long-term degradation in water quality can be identified. However, in the low recharge areas
within the distal portions of the alluvial fan, there has been a degradation in water quality with time. The degradation is
caused by the dissolution of the Lisan Marl, which is present at the outskirts of the fan system, based on hydrochemistry
of water in the wells. The Dhiraa field is a deep (800–950 m) aquifer drilled specifically for the extraction of brackish
water present in the Kurnub aquifer. Available data indicate that there are at least three distinct water types within this
field. These water types are variable in quality, and there may be potential for mixing of these waters, thus affecting the
quality of the freshest waters presently available. Tritium and oxygen isotope analysis indicate that the water is old and
possibly nonrenewable.
Received: 24 July 1995 · Accepted: 26 September 1995 相似文献
17.
The evaluation of the vulnerability of the karst aquifer and the source in the Coteţul Dobreştilor system was performed on
the basis of geological, hydrogeological and pedological data. The methods proposed in the Final Report of COST Action 620
were used. The available field data resulted in assessing the parameters P, I and in characterizing the saturated aquifer karstic network parameter (K). The soil cover over the carbonate deposits is generally shallow and easily bypassed by the superficial flow, the protection
of the karstic aquifer and the source thus being minimal. 相似文献
18.
A Methodology for Establishing a Data Reliability Measure for Value of Spatial Information Problems 总被引：2，自引：0，他引：2
We propose a value of information (VOI) methodology for spatial Earth problems. VOI is a tool to determine whether purchasing
a new information source would improve a decision-makers’ chances of taking the optimal action. A prior uncertainty assessment
of key geologic parameters and a reliability of the data to resolve them are necessary to make a VOI assessment. Both of these
elements are challenging to obtain, as this assessment is made before the information is acquired. We present a flexible prior
geologic uncertainty modeling scheme that allows for the inclusion of many types of spatial parameter. Next, we describe how
to obtain a physics-based reliability measure by simulating the geophysical measurement on the generated prior models and
interpreting the simulated data. Repeating this simulation and interpretation for all datasets, a frequency table can be obtained
that describes how many times a correct or false interpretation was made by comparing them to their respective original model.
This frequency table is the reliability measure and allows a more realistic VOI calculation. An example VOI calculation is
demonstrated for a spatial decision related to aquifer recharge where two geophysical techniques are considered for their
ability to resolve channel orientations. As necessitated by spatial problems, this methodology preserves the structure, influence
and dependence of spatial variables through the prior geological modeling and the explicit geophysical simulation and interpretations. 相似文献
19.
Eleonora S. Carol Eduardo E. Kruse Patricia C. Laurencena Adolfo Rojo Marta H. Deluchi 《Environmental Earth Sciences》2012,65(2):421-428
The phreatic aquifer beneath the Pampean plain, in eastern central Argentina, constitutes a relevant source of water supply
in the area. The objective of this work was to assess the significance of the cation exchange processes in the hydrochemical
evolution of this aquifer, based on a study case located in the middle and upper basin of the El Pescado creek. Results indicate
that Ca2+/Na+ exchange is the main process determining the evolution of groundwater from the recharge areas (Ca–HCO3) towards the local discharge areas (Na–HCO3), as well as representing a source of Na+ contribution to the water in the aquifer. This hydrochemical characteristic is central to the identification of local discharge
areas within a plain environment which extends regionally. The ion exchange capacity of these discharge areas has environmental
importance, due to its influence on groundwater quality and potential groundwater uses. These results may be applied to any
aquifer sharing similar hydrogeological characteristics. 相似文献
20.
《Chemie der Erde / Geochemistry》2014,74(4):671-680
The Janah alluvial aquifer is located in southern Iran with an arid climate. The type of groundwater in this aquifer is dominantly of sodium chloride and total dissolved solid of groundwater samples range from 1.63 to 335 g/L which confirms that groundwater quality has been severely degraded by salinization. Hydrogeochemical and isotopic investigations were conducted to identify the source of salinity. Total dissolved solids and major ion concentrations were measured at 51 selected sampling sites including springs, wells and surface waters. In addition stable isotopic composition (oxygen-18 and deuterium) was measured in 6 sampling points.The study indicates that the sources of salinity of the Janah aquifer include dissolution of salt diapir and evaporite rocks, a geothermal spring and intrusion of the river water which function individually or together in different parts of the aquifer. Based on the hydrogeochemical and geological studies conceptual flow models were prepared for different parts of the aquifer which illustrate how each source of salinity deteriorates the quality of the alluvial aquifer. We proposed few remediation methods including construction of cemented channel and sealed basins to improve groundwater quality. These methods would prevent infiltration of low quality water into the alluvial aquifer. 相似文献