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1.
S. A. Alagbe 《Environmental Geology》2006,51(1):39-45
Hydrochemical investigations in the Kalambaina Formation have been initiated to determine potability and suitability of the shallow groundwater for domestic and agricultural uses. This limestone formation is an extensive aquifer supplying water to livestock and domestic wells in its outcrop areas. The aquifer is recharged by rainfall and discharges mainly into the Sokoto–Rima River system and lakes at Kware, Gwadabawa and Kalmalo in Nigeria. Because recharge to the aquifer is mainly from rainfall, the quality of the groundwater is controlled essentially by chemical processes in the vadose zone and locally by human activities. Water samples were taken at 11 sites comprising boreholes, dug wells and a spring and were chemically analysed for their major ion components. Hydrochemical results show water of fairly good quality. It is, however, hard and generally of moderate dissolved solids content. Concentration of the total dissolved solids is between 130 and 2,340 mg/l. Concentrations of ions vary widely but a high concentration of K+ is found in places. NO3− is on the higher side of the World Health Organization (WHO) permissible limits, indicating pollution in such areas. Groundwater chemistry is predominantly of two facies, namely the calcium–magnesium–bicarbonate and calcium–magnesium–sulphate–chloride facies. These facies probably evolved primarily as a result of dissolution of calcium and magnesium carbonates as well as some human/land-use activities. 相似文献
2.
The Heretaunga Plains, Hawke's Bay, New Zealand, is underlain by Quaternary fluvial, estuarine-lagoonal, and marine deposits
infilling a subsiding syncline. Within the depositional sequence, river-channel gravels form one of the most important aquifer
systems in New Zealand. An interconnected unconfined–confined aquifer system contains groundwater recharged from the Ngaruroro
River bed at the inland margin of the plain, 20 km from the coast. At the coast, gravel aquifers extend to a depth of 250 m.
In 1994–95, 66 Mm3 of high quality groundwater was abstracted for city and rural water supply, agriculture, industry, and horticulture. Use
of groundwater, particularly for irrigation, has increased in the last 5 years. Concern as to the sustainability of the groundwater
resource led to a research programme (1991–96). This paper presents the results and recommends specific monitoring and research
work to refine the groundwater balance, and define and maintain the sustainable yield of the aquifer system. Three critical
management factors are identified. These are (1) to ensure maintenance of consistent, unimpeded groundwater recharge from
the Ngaruroro River; (2) to specifically monitor groundwater levels and quality at the margins of the aquifer system, where
transmissivity is <5000 m2/d and summer groundwater levels indicate that abstraction exceeds recharge; (3) to review groundwater-quality programs to
ensure that areas where contamination vulnerability is identified as being highest are covered by regular monitoring.
Received, January 1998 / Revised, August 1998, March 1999 / Accepted, April 1999 相似文献
3.
H. Khérici-Bousnoubra N. Khérici E. F. Derradji C. Rousset R. Caruba 《Environmental Geology》2009,57(7):1619-1624
Industrial wastewater is characterised by the presence of a great quantity of metallic micro-pollutants, among which chromium
by its mobility, contaminates the surface and groundwater. The study of different aquifers within the area of Annaba (Algeria)
shows extremely variable chromium concentrations in the unconfined aquifer (0–0.22 mg l−1), which becomes practically null in dry period; on the other hand, they remain relatively constant in the deep confined aquifer
(about 0.04 mg l−1). To specify the mechanisms of chromium migration in the aquifer system, a study of space–time evolution of chromium concentrations
in unconfined aquifer was undertaken, while considering the kinetics of diffusion in the deeper aquifer. Chromium, indirectly
reduced microbiologically by sulphate-reducer bacteria in the upper aquifer, is likely to anticipate the auto-depuration capacity
of the ground and to reduce the quality of groundwater. 相似文献
4.
Hydrochemical evolution and water quality along the groundwater flow path in the Sandıklı plain, Afyon, Turkey 总被引:1,自引:0,他引:1
M. Afşin 《Environmental Geology》1997,31(3-4):221-230
An unconfined aquifer system suggests an open system in the study area. Hydrochemical evolution is related to the flow path
of groundwater. The groundwaters are divided into two hydrochemical facies in the study area, 1) Ca–Mg–HCO3 and 2) Ca–Mg–SO4HCO3. Facies 1 has shallow (young) waters which dominate in recharge areas during rapid flow conditions, whereas facies 2 may
show shallow and mixed waters which dominate intermediate or discharge areas during low flow conditions. Ionic concentrations,
TDS, EC and water quality are related to groundwater residence time and groundwater types. The groundwaters in the plain are
chemically potable and suitable for both domestic and agricultural purposes.
Received: 20 May 1996 · Accepted: 30 July 1996 相似文献
5.
Paula Galego Fernandes Paula Carreira Manuel Oliveira da Silva 《Mathematical Geology》2006,38(6):765-780
The Sines coastal sedimentary basin, a tectonic trough with a NE-SW orientation filled with Mesozoic and Cenozoic deposits,
has two hydrogeological systems: the Mio-Pliocene and the Jurassic. Both systems are supplying water to the entire region
with highly populated and industrialized areas. The aquifers are recharged in the outcrop areas, although the Jurassic aquifer
also receives some contribution from the overlying Miocene rocks. The main groundwater flow direction in the Jurassic aquifer
is E to W towards the Atlantic Ocean.
In order to understand the influence of anthropogenic activities on the water quality, a statistical principal components
analysis (PCA) was performed on the physical–chemical data from groundwater samples in both aquifers. Four components were
obtained in the Jurassic and three in the Miocene. The principal components analyses indicate water–rock interactions as the
major mechanism responsible for the groundwater solutes (mainly calcium-bicarbonate type), from the calcareous and dolomitic
units. Anthropogenic contamination was identified in the influence of the water compositions, corresponding to local polluting
inputs. These were magnesium, sulfate, nitrate, iron and copper for PC 3 in the Jurassic and sodium, chloride, nitrate and
manganese for PC 2 in the Miocene. These account for about 13% of the system total variance in the Jurassic aquifer and near
23% in the Miocene one. 相似文献
6.
Sanjiang Plain-Amur River Basin aquifer is the aquifer shared by China and Russia, which is of great significance to water sources management for both countries, acting as a focused area by China and Russia. In this paper, the hydrogeological characteristics of the Sanjiang Plain-Amur River Basin is studied, aiming at understanding the differences as well as similarities of aquifer classification, chemical characteristics of groundwater, quantity of groundwater and groundwater evaluation methods of two countries, which will lay a solid foundation to further holistic study of the trans-boundary aquifer in the Sanjiang Plain-Amur River Basin. 相似文献
7.
Waleed K. Zubari 《Hydrogeology Journal》1999,7(2):197-208
Over-abstraction of the Dammam aquifer, the principal aquifer in Bahrain, by the agricultural and domestic sectors, has led
to its salinization by adjacent brackish and saline water bodies. A hydrochemical study identified the locations of the sources
of aquifer salinization and delineated their areas of influence. The investigation indicates that the aquifer water quality
is significantly modified as groundwater flows from the northwestern parts of Bahrain, where the aquifer receives its water
by lateral underflow from eastern Saudi Arabia, to the southern and southeastern parts. Four types of salinization of the
aquifer are identified: brackish-water up-flow from the underlying brackish-water zones in north-central, western, and eastern
regions; seawater intrusion in the eastern region; intrusion of sabkha water in the southwestern region; and irrigation return
flow in a local area in the western region. Four alternatives for the management of groundwater quality that are available
to the water authorities in Bahrain are discussed and their priority areas are proposed, based on the type and extent of each
salinization source, in addition to groundwater use in that area. The effectiveness of the proposed management options in
controlling the degradation of water quality in the Dammam aquifer should be evaluated using simulation modeling.
Received: June 1998 Revised: November 1998 Accepted: December 1998 相似文献
8.
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
9.
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
10.
Jinlong Zhou Guomin Li Feng Liu Yiping Wang Xiaojing Guo 《Environmental Earth Sciences》2010,60(5):1055-1063
According to the characteristics of groundwater in arid area, this paper proposes DRAV model for groundwater vulnerability
assessment, where D is groundwater depth, R is the net recharge of aquifer, A is the aquifer characteristics, and V is the lithology of vadose zone. As a case study, the paper assesses the vulnerability of pore phreatic water in Tarim Basin
of Xinjiang, China by using the DRAV model. The results indicate that the areas of phreatic water with vulnerability index
ranges of 2–4, 4–6, 6–8 and >8 accounting for 10.1, 80.4, 9.2 and 0.2% of the total plain area of the Tarim Basin respectively,
and the areas with the latter two vulnerability ranges (6–8 and >8) are mainly located in the irrigation districts with thin
soil layer (20–30 cm thick surface soil of vadose zone, mainly with underlying sandy gravel) and with silty and fine sand
layer. Such vadose zone generally lacks sandy loam and clayey soil and has larger recharge by infiltration of irrigation water. 相似文献
11.
An extension to the DRASTIC model is proposed in order to assess aquifer vulnerability to pollution. In contrast to the DRASTIC
model, which considers the unsaturated and saturated zones together and computes a global intrinsic vulnerability index, the
suggested approach discriminates between the aquifer vertical vulnerability (a concept related to the pollutant percolation)
and the groundwater susceptibility (a concept that depends on the behaviour and uses of the groundwater). This approach is
applied to the Haouz aquifer (Morocco) that supplies water to the Marrakech area. This aquifer is widely overexploited and
there is evidence that the groundwater quality is threatened by various sources of pollution. Evaluation of the vertical vulnerability
indicates that the aquifer mainly presents a moderate-to-weak vertical vulnerability. The zones potentially most favourable
to pollutant percolation are mainly located in Central Haouz, along or near the surface wadis. The aquifer susceptibility
is high in places located near the N’Fis, Baaja and Issil wadis. Everywhere else, low-to-moderate susceptibility is observed.
This new approach therefore enables areas of vertical vulnerability and areas of susceptibility to be delineated separately.
As a result, it constitutes a valuable decision-making tool for optimising the management of aquifer water resources and land-use
planning. 相似文献
12.
Forecasting of groundwater level in hard rock region using artificial neural network 总被引:2,自引:0,他引:2
In hardrock terrain where seasonal streams are not perennial source of freshwater, increase in ground water exploitation has
already resulted here in declining ground water levels and deteriorating its’ quality. The aquifer system has shown signs
of depletion and quality contamination. Thus, to secure water for the future, water resource estimation and management has
urgently become the need of the hour. In order to manage groundwater resources, it is vital to have a tool to predict the
aquifer response for a given stress (abstraction and recharge). Artificial neural network (ANN) has surfaced as a proven and
potential methodology to forecast the groundwater levels. In this paper, Feed-Forward Network based ANN model is used as a
method to predict the groundwater levels. The models are trained with the inputs collected from field and then used as prediction
tool for various scenarios of stress on aquifer. Such predictions help in developing better strategies for sustainable development
of groundwater resources. 相似文献
13.
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
14.
V. S. Singh 《Environmental Geology》1999,38(2):168-170
Estimation of aquifer parameters is vital for the assessment of groundwater potential and groundwater flow regime. On an
oceanic island where fresh water lens is fragile and sensitive to various stresses, it is even more essential that in order
to assess the potential of fresh water lens and the effect of various stresses on the fresh groundwater regime the parameters
should be representative to the field hydrogeological set up. Pumping tests conducted on existing large diameter wells on
an oceanic island have been analyzed. A finite difference method has been used to take into account the well storage, partial
penetration and upconing effect into the aquifer. Forward modeling has been carried out to estimate aquifer parameters from
the pumping test data. Field examples are described.
Received: 15 June 1998 · Accepted: 25 August 1998 相似文献
15.
Analyses of 126 samples collected from 18 dug wells in the shallow basaltic aquifer over a period of 7 months have revealed
spatial as well as temporal changes in the chemical properties of groundwater. While the temporal changes have been attributed
to dilution and concentration phenomena governed by climatic factors, the spatial variations in the geochemical characteristics
of groundwater appeared to be related to pollution due to effluents from the Mula Sugar Factory. The cause of groundwater
pollution is the effluent carried by a stream flowing through the area. Fluctuations in the groundwater table, influent water
quality character of the stream, less capacity to accommodate large volume of effluent and occurrence of zero base flow (under
natural conditions) in the stream are the factors favoring infiltration of constituents of waste water into the underlying
weathered basaltic aquifer. Pollutants have entered into the shallow aquifer by downward percolation through the zone of aeration
to form a recharge mound at the water table and, further, lateral movement below the water table. The plume of polluted groundwater
has a lateral extent of a few meters in the upstream area and more than 400 m on either side of the stream in the downstream
part. The zone of polluted groundwater has an areal extent of more than 3.5 km2. Groundwater is the only source available for drinking and agricultural purposes. It is recommended that the base of the
lagoons and the stream used for release of plant effluent should be waterproofed for the protection of groundwater in the
Sonai area.
Received: 30 April 1997 · Accepted: 23 September 1997 相似文献
16.
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
17.
A data-driven approach for analyzing dynamics of tide–aquifer interaction in coastal aquifer systems
Analysis of tidal effects on aquifer systems plays an important role in coastal aquifer management owing to various hydrological,
engineering and environmental problems in coastal areas. Using the real-world data of unconfined and confined aquifers, a
data-driven approach is presented in this study for the analysis of tide–aquifer interaction in coastal aquifers. Six analytical
tide–aquifer interaction models were selected which take into account the effects of vertical beach, sloping beach, tidal
loading, aquifer leakage, outlet capping, and combined leakage and outlet capping on tide-induced groundwater fluctuations.
The tide–aquifer interaction datasets were obtained from the Konan groundwater basin (unconfined aquifer) of Japan and the
Dridrate groundwater basin (confined aquifer) of Morocco. The analysis of the results obtained by the sloping beach model
revealed that for a given beach slope, the amplitude of groundwater level increases with an increase in aquifer diffusivity
and a decrease in aquifer thickness. However, no significant effect of beach slope was observed in this study at unconfined
sites for all the datasets. The influence of tidal loading was found to be considerably less for all the three confined sites.
Further, the analysis of the results of the leakage model indicated that with an increase in leakage into the aquifer, the
amplitude of groundwater level as well as the phase shift (time lag) decreases. Of all the confined and unconfined datasets,
only two confined sites were found to be affected by outlet capping. Overall, it is concluded that the coastal beach bordering
the Konan basin is not significantly sloping, the contribution of tidal loading to tide-induced groundwater fluctuations in
the Dridrate aquifer is not appreciable, and that the aquifer leakage and outlet capping do not exist at the unconfined sites
under investigation. 相似文献
18.
Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA 总被引:3,自引:1,他引:3
Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater
from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions
affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate
reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and
(4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers
are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting,
at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in
the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water
from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone
Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20–30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during
the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰.
Electronic Publication 相似文献
19.
Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields 总被引:2,自引:0,他引:2
Yonghong Hao Tian-Chyi J. Yeh Caihong Hu Yanrong Wang Xia Li 《Environmental Geology》2006,50(3):415-422
In a semiarid region, the karst aquifer generally forms a large groundwater reservoir that can play an important role in regional water supply. But because of the specific physical properties of karst aquifers, they are vulnerable to pollution and anthropogenic impacts. Karst groundwater management strategies are vital. As representative of karst springs in a semiarid area, Niangziguan Springs is located in the east of Shanxi Province, China with an annual average rate of discharge of 10.34 m3/s (1956–2003) (Y. Liang, unpublished data). The Niangziguan Spring Basin covers an area of 7,394 km2 with an annual average precipitation of 535 mm (1958–2003) (Hao et al. in Carsologica Sinica 23(1):43–47, 2004). Over the past three decades, accelerated groundwater exploitation has caused water-table decline in the aquifer, reduction of the spring discharge, and deterioration of water quality. In this study, three protection zones were defined to ensure the quality and capacity of this resource. The confluence of the 11 spring systems and the discharge areas were defined as I protection zone, the recharge basin was II protection zone, and the slack water area where there is little surface recharge was the III protection zone. Management strategies for each zone were suggested and evaluated to provide a scientific foundation for sustainable utilization. 相似文献
20.
The study was carried out in order to investigate existing hydrogeochemical relationships between groundwater environment
and geological units in the Kazan trona deposit area, Ankara, Turkey. Evaluations indicate that concentrations of alkalinity,
boron, chloride and sodium in the upgradient groundwater of the Eocene sedimentary units gradually increase toward downgradient
by the interactions of saline minerals (searlesite, shortite, northupite and pyrite) present in the secondary structures (microfractures
and irregular voids) at various levels. Inverse modeling calculations suggest that the range of dissolved mass amounts in
millimoles per kilogram of water for searlesite, shortite and northupite minerals are 0.05–28.67, 2.62–24.39 and 0.01–24.19,
respectively, in the aquifer between the upgradient and downgradient locations. The ranges of accompanying calcite and dolomite
precipitations are 4.54–48.71 and 2.16–24.08 mmol per kg of water, respectively. Chemical composition of the groundwater in
the overlying Neogene sedimentary unit includes also higher concentrations of the major ions as measured in groundwater of
the underlying units. However the lack of saline mineral zones in the Neogene unit indicates that upward groundwater mixing
takes place from the underlying aquifer as also suggested by the measured upward gradient. The mixing percentage of the underlying
groundwater as determined from the nested wells ranges from 2.7 to 48.3%, from upgradient to downgradient, respectively. The
unconfined alluvium aquifer overlying the Neogene unit includes relatively dilute groundwater except in two locations, where
high-ion concentrations detected in groundwater of the underlying units are also high in these locations, suggesting upward
groundwater mixing from the underlying aquifer due to upward gradient. However, groundwater input investigations from the
alluvium aquifer to the nearby Ova stream indicate that the detected high concentrations in these locations are diluted or
sorbed by the aquifer material toward downgradient (Ova Stream). 相似文献